diff --git a/doc/bird.sgml b/doc/bird.sgml
index f10b15e2..6d9847dc 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -252,16 +252,9 @@ The global best route selection algorithm is (roughly) as follows:
 </itemize>
 
 <p><label id="dsc-table-sorted">Usually, a routing table just chooses a selected
-route from a list of entries for one network. But if the <cf/sorted/ option is
-activated, these lists of entries are kept completely sorted (according to
-preference or some protocol-dependent metric). This is needed for some features
-of some protocols (e.g. <cf/secondary/ option of BGP protocol, which allows to
-accept not just a selected route, but the first route (in the sorted list) that
-is accepted by filters), but it is incompatible with some other features (e.g.
-<cf/deterministic med/ option of BGP protocol, which activates a way of choosing
-selected route that cannot be described using comparison and ordering). Minor
-advantage is that routes are shown sorted in <cf/show route/, minor disadvantage
-is that it is slightly more computationally expensive.
+route from a list of entries for one network. Optionally, these lists of entries
+are kept completely sorted (according to preference or some protocol-dependent
+metric). See <ref id="rtable-sorted" name="sorted"> table option for details.
 
 <sect>Routes and network types
 <label id="routes">
@@ -628,18 +621,73 @@ include "tablename.conf";;
 	<cf/protocol/ times, and the <cf/iso long ms/ format for <cf/base/ and
 	<cf/log/ times.
 
-	<tag><label id="opt-table"><m/nettype/ table <m/name/ [sorted]</tag>
-	Create a new routing table. The default routing tables <cf/master4/ and
-	<cf/master6/ are created implicitly, other routing tables have to be
-	added by this command.  Option <cf/sorted/ can be used to enable sorting
-	of routes, see <ref id="dsc-table-sorted" name="sorted table">
-	description for details.
+	<tag><label id="opt-table"><m/nettype/ table <m/name/ [ { <m/option/; [<m/.../] } ]</tag>
+	Define a new routing table. The default routing tables <cf/master4/ and
+	<cf/master6/ are defined implicitly, other routing tables have to be
+	defined by this option. See the <ref id="rtable-opts"
+	name="routing table configuration section"> for routing table options.
 
 	<tag><label id="opt-eval">eval <m/expr/</tag>
 	Evaluates given filter expression. It is used by the developers for testing of filters.
 </descrip>
 
 
+<sect>Routing table options
+<label id="rtable-opts">
+
+<p>Most routing tables do not need any options and are defined without an option
+block, but there are still some options to tweak routing table behavior. Note
+that implicit tables (<cf/master4/ and <cf/master6/) can be redefined in order
+to set options.
+
+<descrip>
+	<tag><label id="rtable-sorted">sorted <m/switch/</tag>
+	Usually, a routing table just chooses the selected (best) route from a
+	list of routes for each network, while keeping remaining routes unsorted.
+	If enabled, these lists of routes are kept completely sorted (according
+	to preference or some protocol-dependent metric).
+
+	This is needed for some protocol features (e.g. <cf/secondary/ option of
+	BGP protocol, which allows to accept not just a selected route, but the
+	first route (in the sorted list) that is accepted by filters), but it is
+	incompatible with some other features (e.g. <cf/deterministic med/
+	option of BGP protocol, which activates a way of choosing selected route
+	that cannot be described using comparison and ordering). Minor advantage
+	is that routes are shown sorted in <cf/show route/, minor disadvantage
+	is that it is slightly more computationally expensive. Default: off.
+
+	<tag><label id="rtable-trie">trie <m/switch/</tag>
+	BIRD routing tables are implemented with hash tables, which is efficient
+	for exact-match lookups, but inconvenient for longest-match lookups or
+	interval lookups (finding superprefix or subprefixes). This option
+	activates additional trie structure that is used to accelerate these
+	lookups, while using the hash table for exact-match lookups.
+
+	This has advantage for <ref id="rpki" name="RPKI"> (on ROA tables),
+	for <ref id="bgp-gateway" name="recursive next-hops"> (on IGP tables),
+	and is required for <ref id="bgp-validate" name="flowspec validation">
+	(on base IP tables). Another advantage is that interval results (like
+	from <cf/show route in .../ command) are lexicographically sorted. The
+	disadvantage is that trie-enabled routing tables require more memory,
+	which may be an issue especially in multi-table setups. Default: off.
+
+	<tag><label id="rtable-min-settle-time">min settle time <m/time/</tag>
+	Specify a minimum value of the settle time. When a ROA table changes,
+	automatic <ref id="proto-rpki-reload" name="RPKI reload"> may be
+	triggered, after a short settle time. Minimum settle time is a delay
+	from the last ROA table change to wait for more updates. Default: 1 s.
+
+
+	<tag><label id="rtable-max-settle-time">max settle time <m/time/</tag>
+	Specify a maximum value of the settle time. When a ROA table changes,
+	automatic <ref id="proto-rpki-reload" name="RPKI reload"> may be
+	triggered, after a short settle time. Maximum settle time is an upper
+	limit to the settle time from the initial ROA table change even if
+	there are consecutive updates gradually renewing the settle time.
+	Default: 20 s.
+</descrip>
+
+
 <sect>Protocol options
 <label id="protocol-opts">
 
@@ -2290,6 +2338,7 @@ avoid routing loops.
 <item> <rfc id="8092"> - BGP Large Communities Attribute
 <item> <rfc id="8203"> - BGP Administrative Shutdown Communication
 <item> <rfc id="8212"> - Default EBGP Route Propagation Behavior without Policies
+<item> <rfc id="9117"> - Revised Validation Procedure for BGP Flow Specifications
 </itemize>
 
 <sect1>Route selection rules
@@ -2674,7 +2723,7 @@ using the following configuration parameters:
 
 	<tag><label id="bgp-error-wait-time">error wait time <m/number/,<m/number/</tag>
 	Minimum and maximum delay in seconds between a protocol failure (either
-	local or reported by the peer) and automatic restart. Doesn't apply
+	local or reported by the peer) and automatic restart. Doesn not apply
 	when <cf/disable after error/ is configured. If consecutive errors
 	happen, the delay is increased exponentially until it reaches the
 	maximum. Default: 60, 300.
@@ -2852,6 +2901,31 @@ be used in explicit configuration.
 	explicitly (to conserve memory). This option requires that the connected
 	routing table is <ref id="dsc-table-sorted" name="sorted">. Default: off.
 
+	<tag><label id="bgp-validate">validate <m/switch/</tag>
+	Apply flowspec validation procedure as described in <rfc id="8955">
+	section 6 and <rfc id="9117">. The Validation procedure enforces that
+	only routers in the forwarding path for a network can originate flowspec
+	rules for that network. The validation procedure should be used for EBGP
+	to prevent injection of malicious flowspec rules from outside, but it
+	should also be used for IBGP to ensure that selected flowspec rules are
+	consistent with selected IP routes. The validation procedure uses an IP
+	routing table (<ref id="bgp-base-table" name="base table">, see below)
+	against which flowspec rules are validated. This option is limited to
+	flowspec channels. Default: off (for compatibility reasons).
+
+	Note that currently the flowspec validation does not work reliably
+	together with <ref id="bgp-import-table" name="import table"> option
+	enabled on flowspec channels.
+
+	<tag><label id="bgp-base-table">base table <m/name/</tag>
+	Specifies an IP table used for the flowspec validation procedure. The
+	table must have enabled <cf/trie/ option, otherwise the validation
+	procedure would not work. The type of the table must be <cf/ipv4/ for
+	<cf/flow4/ channels and <cf/ipv6/ for <cf/flow6/ channels. This option
+	is limited to flowspec channels. Default: the main table of the
+	<cf/ipv4/ / <cf/ipv6/ channel of the same BGP instance, or the
+	<cf/master4/ / <cf/master6/ table if there is no such channel.
+
 	<tag><label id="bgp-extended-next-hop">extended next hop <m/switch/</tag>
 	BGP expects that announced next hops have the same address family as
 	associated network prefixes. This option provides an extension to use
diff --git a/filter/data.h b/filter/data.h
index bb815c34..4cb6b7a8 100644
--- a/filter/data.h
+++ b/filter/data.h
@@ -140,18 +140,23 @@ struct f_tree {
   void *data;
 };
 
+#define TRIE_STEP		4
+#define TRIE_STACK_LENGTH	33
+
 struct f_trie_node4
 {
   ip4_addr addr, mask, accept;
-  uint plen;
-  struct f_trie_node4 *c[2];
+  u16 plen;
+  u16 local;
+  struct f_trie_node4 *c[1 << TRIE_STEP];
 };
 
 struct f_trie_node6
 {
   ip6_addr addr, mask, accept;
-  uint plen;
-  struct f_trie_node6 *c[2];
+  u16 plen;
+  u16 local;
+  struct f_trie_node6 *c[1 << TRIE_STEP];
 };
 
 struct f_trie_node
@@ -168,9 +173,20 @@ struct f_trie
   u8 zero;
   s8 ipv4;				/* -1 for undefined / empty */
   u16 data_size;			/* Additional data for each trie node */
+  u32 prefix_count;			/* Works only for restricted tries (pxlen == l == h) */
   struct f_trie_node root;		/* Root trie node */
 };
 
+struct f_trie_walk_state
+{
+  u8 ipv4;
+  u8 accept_length;			/* Current inter-node prefix position */
+  u8 start_pos;				/* Initial prefix position in stack[0] */
+  u8 local_pos;				/* Current intra-node prefix position */
+  u8 stack_pos;				/* Current node in stack below */
+  const struct f_trie_node *stack[TRIE_STACK_LENGTH];
+};
+
 struct f_tree *f_new_tree(void);
 struct f_tree *build_tree(struct f_tree *);
 const struct f_tree *find_tree(const struct f_tree *t, const struct f_val *val);
@@ -181,9 +197,70 @@ void tree_walk(const struct f_tree *t, void (*hook)(const struct f_tree *, void
 struct f_trie *f_new_trie(linpool *lp, uint data_size);
 void *trie_add_prefix(struct f_trie *t, const net_addr *n, uint l, uint h);
 int trie_match_net(const struct f_trie *t, const net_addr *n);
+int trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr_ip4 *dst, ip4_addr *found0);
+int trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr_ip6 *dst, ip6_addr *found0);
+void trie_walk_init(struct f_trie_walk_state *s, const struct f_trie *t, const net_addr *from);
+int trie_walk_next(struct f_trie_walk_state *s, net_addr *net);
 int trie_same(const struct f_trie *t1, const struct f_trie *t2);
 void trie_format(const struct f_trie *t, buffer *buf);
 
+static inline int
+trie_match_next_longest_ip4(net_addr_ip4 *n, ip4_addr *found)
+{
+  while (n->pxlen)
+  {
+    n->pxlen--;
+    ip4_clrbit(&n->prefix, n->pxlen);
+
+    if (ip4_getbit(*found, n->pxlen))
+      return 1;
+  }
+
+  return 0;
+}
+
+static inline int
+trie_match_next_longest_ip6(net_addr_ip6 *n, ip6_addr *found)
+{
+  while (n->pxlen)
+  {
+    n->pxlen--;
+    ip6_clrbit(&n->prefix, n->pxlen);
+
+    if (ip6_getbit(*found, n->pxlen))
+      return 1;
+  }
+
+  return 0;
+}
+
+
+#define TRIE_WALK_TO_ROOT_IP4(trie, net, dst) ({		\
+  net_addr_ip4 dst;						\
+  ip4_addr _found;						\
+  for (int _n = trie_match_longest_ip4(trie, net, &dst, &_found); \
+       _n;							\
+       _n = trie_match_next_longest_ip4(&dst, &_found))
+
+#define TRIE_WALK_TO_ROOT_IP6(trie, net, dst) ({		\
+  net_addr_ip6 dst;						\
+  ip6_addr _found;						\
+  for (int _n = trie_match_longest_ip6(trie, net, &dst, &_found); \
+       _n;							\
+       _n = trie_match_next_longest_ip6(&dst, &_found))
+
+#define TRIE_WALK_TO_ROOT_END })
+
+
+#define TRIE_WALK(trie, net, from) ({				\
+  net_addr net;							\
+  struct f_trie_walk_state tws_;				\
+  trie_walk_init(&tws_, trie, from);				\
+  while (trie_walk_next(&tws_, &net))
+
+#define TRIE_WALK_END })
+
+
 #define F_CMP_ERROR 999
 
 const char *f_type_name(enum f_type t);
diff --git a/filter/test.conf b/filter/test.conf
index f902f99f..484628e5 100644
--- a/filter/test.conf
+++ b/filter/test.conf
@@ -499,6 +499,33 @@ prefix set pxs;
 
 	bt_assert(1.2.0.0/16 ~ [ 1.0.0.0/8{ 15 , 17 } ]);
 	bt_assert([ 10.0.0.0/8{ 15 , 17 } ] != [ 11.0.0.0/8{ 15 , 17 } ]);
+
+	/* Formatting of prefix sets, some cases are a bit strange */
+	bt_assert(format([ 0.0.0.0/0 ]) = "[0.0.0.0/0]");
+	bt_assert(format([ 10.10.0.0/32 ]) = "[10.10.0.0/32{0.0.0.1}]");
+	bt_assert(format([ 10.10.0.0/17 ]) = "[10.10.0.0/17{0.0.128.0}]");
+	bt_assert(format([ 10.10.0.0/17{17,19} ]) = "[10.10.0.0/17{0.0.224.0}]"); # 224 = 128+64+32
+	bt_assert(format([ 10.10.128.0/17{18,19} ]) = "[10.10.128.0/18{0.0.96.0}, 10.10.192.0/18{0.0.96.0}]"); # 96 = 64+32
+	bt_assert(format([ 10.10.64.0/18- ]) = "[0.0.0.0/0, 0.0.0.0/1{128.0.0.0}, 0.0.0.0/2{64.0.0.0}, 0.0.0.0/3{32.0.0.0}, 10.10.0.0/16{255.255.0.0}, 10.10.0.0/17{0.0.128.0}, 10.10.64.0/18{0.0.64.0}]");
+	bt_assert(format([ 10.10.64.0/18+ ]) = "[10.10.64.0/18{0.0.96.0}, 10.10.64.0/20{0.0.31.255}, 10.10.80.0/20{0.0.31.255}, 10.10.96.0/20{0.0.31.255}, 10.10.112.0/20{0.0.31.255}]");
+
+	bt_assert(format([ 10.10.160.0/19 ]) = "[10.10.160.0/19{0.0.32.0}]");
+	bt_assert(format([ 10.10.160.0/19{19,22} ]) = "[10.10.160.0/19{0.0.32.0}, 10.10.160.0/20{0.0.28.0}, 10.10.176.0/20{0.0.28.0}]"); # 28 = 16+8+4
+	bt_assert(format([ 10.10.160.0/19+ ]) = "[10.10.160.0/19{0.0.32.0}, 10.10.160.0/20{0.0.31.255}, 10.10.176.0/20{0.0.31.255}]");
+
+	bt_assert(format([ ::/0 ]) = "[::/0]");
+	bt_assert(format([ 11:22:33:44:55:66:77:88/128 ]) = "[11:22:33:44:55:66:77:88/128{::1}]");
+	bt_assert(format([ 11:22:33:44::/64 ]) = "[11:22:33:44::/64{0:0:0:1::}]");
+	bt_assert(format([ 11:22:33:44::/64+ ]) = "[11:22:33:44::/64{::1:ffff:ffff:ffff:ffff}]");
+
+	bt_assert(format([ 11:22:33:44::/65 ]) = "[11:22:33:44::/65{::8000:0:0:0}]");
+	bt_assert(format([ 11:22:33:44::/65{65,67} ]) = "[11:22:33:44::/65{::e000:0:0:0}]"); # e = 8+4+2
+	bt_assert(format([ 11:22:33:44:8000::/65{66,67} ]) = "[11:22:33:44:8000::/66{::6000:0:0:0}, 11:22:33:44:c000::/66{::6000:0:0:0}]"); # 6 = 4+2
+	bt_assert(format([ 11:22:33:44:4000::/66- ]) = "[::/0, ::/1{8000::}, ::/2{4000::}, ::/3{2000::}, 11:22:33:44::/64{ffff:ffff:ffff:ffff::}, 11:22:33:44::/65{::8000:0:0:0}, 11:22:33:44:4000::/66{::4000:0:0:0}]");
+	bt_assert(format([ 11:22:33:44:4000::/66+ ]) = "[11:22:33:44:4000::/66{::6000:0:0:0}, 11:22:33:44:4000::/68{::1fff:ffff:ffff:ffff}, 11:22:33:44:5000::/68{::1fff:ffff:ffff:ffff}, 11:22:33:44:6000::/68{::1fff:ffff:ffff:ffff}, 11:22:33:44:7000::/68{::1fff:ffff:ffff:ffff}]");
+	bt_assert(format([ 11:22:33:44:c000::/67 ]) = "[11:22:33:44:c000::/67{::2000:0:0:0}]");
+	bt_assert(format([ 11:22:33:44:c000::/67{67,71} ]) = "[11:22:33:44:c000::/67{::2000:0:0:0}, 11:22:33:44:c000::/68{::1e00:0:0:0}, 11:22:33:44:d000::/68{::1e00:0:0:0}]");
+	bt_assert(format([ 11:22:33:44:c000::/67+ ]) = "[11:22:33:44:c000::/67{::2000:0:0:0}, 11:22:33:44:c000::/68{::1fff:ffff:ffff:ffff}, 11:22:33:44:d000::/68{::1fff:ffff:ffff:ffff}]");
 }
 
 bt_test_suite(t_prefix_set, "Testing prefix sets");
@@ -578,6 +605,12 @@ prefix set pxs;
 	bt_assert(2000::/29 !~ pxs);
 	bt_assert(1100::/10 !~ pxs);
 	bt_assert(2010::/26 !~ pxs);
+
+	pxs = [ 52E0::/13{13,128} ];
+	bt_assert(52E7:BE81:379B:E6FD:541F:B0D0::/93 ~ pxs);
+
+	pxs = [ 41D8:8718::/30{0,30}, 413A:99A8:6C00::/38{38,128} ];
+	bt_assert(4180::/9 ~ pxs);
 }
 
 bt_test_suite(t_prefix6_set, "Testing prefix IPv6 sets");
diff --git a/filter/trie.c b/filter/trie.c
index 1a4e1ac3..12ba0b82 100644
--- a/filter/trie.c
+++ b/filter/trie.c
@@ -1,7 +1,8 @@
 /*
  *	Filters: Trie for prefix sets
  *
- *	Copyright 2009 Ondrej Zajicek <santiago@crfreenet.org>
+ *	(c) 2009--2021 Ondrej Zajicek <santiago@crfreenet.org>
+ *	(c) 2009--2021 CZ.NIC z.s.p.o.
  *
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
@@ -9,53 +10,68 @@
 /**
  * DOC: Trie for prefix sets
  *
- * We use a (compressed) trie to represent prefix sets. Every node
- * in the trie represents one prefix (&addr/&plen) and &plen also
- * indicates the index of the bit in the address that is used to
- * branch at the node. If we need to represent just a set of
- * prefixes, it would be simple, but we have to represent a
- * set of prefix patterns. Each prefix pattern consists of
- * &ppaddr/&pplen and two integers: &low and &high, and a prefix
- * &paddr/&plen matches that pattern if the first MIN(&plen, &pplen)
- * bits of &paddr and &ppaddr are the same and &low <= &plen <= &high.
+ * We use a (compressed) trie to represent prefix sets. Every node in the trie
+ * represents one prefix (&addr/&plen) and &plen also indicates the index of
+ * bits in the address that are used to branch at the node. Note that such
+ * prefix is not necessary a member of the prefix set, it is just a canonical
+ * prefix associated with a node. Prefix lengths of nodes are aligned to
+ * multiples of &TRIE_STEP (4) and there is 16-way branching in each
+ * node. Therefore, we say that a node is associated with a range of prefix
+ * lengths (&plen .. &plen + TRIE_STEP - 1).
  *
- * We use a bitmask (&accept) to represent accepted prefix lengths
- * at a node. As there are 33 prefix lengths (0..32 for IPv4), but
- * there is just one prefix of zero length in the whole trie so we
- * have &zero flag in &f_trie (indicating whether the trie accepts
- * prefix 0.0.0.0/0) as a special case, and &accept bitmask
+ * The prefix set is not just a set of prefixes, it is defined by a set of
+ * prefix patterns. Each prefix pattern consists of &ppaddr/&pplen and two
+ * integers: &low and &high. The tested prefix &paddr/&plen matches that pattern
+ * if the first MIN(&plen, &pplen) bits of &paddr and &ppaddr are the same and
+ * &low <= &plen <= &high.
+ *
+ * There are two ways to represent accepted prefixes for a node. First, there is
+ * a bitmask &local, which represents independently all 15 prefixes that extend
+ * the canonical prefix of the node and are within a range of prefix lengths
+ * associated with the node. E.g., for node 10.0.0.0/8 they are 10.0.0.0/8,
+ * 10.0.0.0/9, 10.128.0.0/9, .. 10.224.0.0/11. This order (first by length, then
+ * lexicographically) is used for indexing the bitmask &local, starting at
+ * position 1. I.e., index is 2^(plen - base) + offset within the same length,
+ * see function trie_local_mask6() for details.
+ *
+ * Second, we use a bitmask &accept to represent accepted prefix lengths at a
+ * node. The bit is set means that all prefixes of given length that are either
+ * subprefixes or superprefixes of the canonical prefix are accepted. As there
+ * are 33 prefix lengths (0..32 for IPv4), but there is just one prefix of zero
+ * length in the whole trie so we have &zero flag in &f_trie (indicating whether
+ * the trie accepts prefix 0.0.0.0/0) as a special case, and &accept bitmask
  * represents accepted prefix lengths from 1 to 32.
  *
- * There are two cases in prefix matching - a match when the length
- * of the prefix is smaller that the length of the prefix pattern,
- * (&plen < &pplen) and otherwise. The second case is simple - we
- * just walk through the trie and look at every visited node
- * whether that prefix accepts our prefix length (&plen). The
- * first case is tricky - we don't want to examine every descendant
- * of a final node, so (when we create the trie) we have to propagate
- * that information from nodes to their ascendants.
+ * One complication is handling of prefix patterns with unaligned prefix length.
+ * When such pattern is to be added, we add a primary node above (with rounded
+ * down prefix length &nlen) and a set of secondary nodes below (with rounded up
+ * prefix lengths &slen). Accepted prefix lengths of the original prefix pattern
+ * are then represented in different places based on their lengths. For prefixes
+ * shorter than &nlen, it is &accept bitmask of the primary node, for prefixes
+ * between &nlen and &slen - 1 it is &local bitmask of the primary node, and for
+ * prefixes longer of equal &slen it is &accept bitmasks of secondary nodes.
  *
- * Suppose that we have two masks (M1 and M2) for a node. Mask M1
- * represents accepted prefix lengths by just the node and mask M2
- * represents accepted prefix lengths by the node or any of its
- * descendants. Therefore M2 is a bitwise or of M1 and children's
- * M2 and this is a maintained invariant during trie building.
- * Basically, when we want to match a prefix, we walk through the trie,
- * check mask M1 for our prefix length and when we came to
- * final node, we check mask M2.
+ * There are two cases in prefix matching - a match when the length of the
+ * prefix is smaller that the length of the prefix pattern, (&plen < &pplen) and
+ * otherwise. The second case is simple - we just walk through the trie and look
+ * at every visited node whether that prefix accepts our prefix length (&plen).
+ * The first case is tricky - we do not want to examine every descendant of a
+ * final node, so (when we create the trie) we have to propagate that
+ * information from nodes to their ascendants.
  *
- * There are two differences in the real implementation. First,
- * we use a compressed trie so there is a case that we skip our
- * final node (if it is not in the trie) and we came to node that
- * is either extension of our prefix, or completely out of path
- * In the first case, we also have to check M2.
+ * There are two kinds of propagations - propagation from child's &accept
+ * bitmask to parent's &accept bitmask, and propagation from child's &accept
+ * bitmask to parent's &local bitmask. The first kind is simple - as all
+ * superprefixes of a parent are also all superprefixes of appropriate length of
+ * a child, then we can just add (by bitwise or) a child &accept mask masked by
+ * parent prefix length mask to the parent &accept mask. This handles prefixes
+ * shorter than node &plen.
  *
- * Second, we really need not to maintain two separate bitmasks.
- * Checks for mask M1 are always larger than &applen and we need
- * just the first &pplen bits of mask M2 (if trie compression
- * hadn't been used it would suffice to know just $applen-th bit),
- * so we have to store them together in &accept mask - the first
- * &pplen bits of mask M2 and then mask M1.
+ * The second kind of propagation is necessary to handle superprefixes of a
+ * child that are represented by parent &local mask - that are in the range of
+ * prefix lengths associated with the parent. For each accepted (by child
+ * &accept mask) prefix length from that range, we need to set appropriate bit
+ * in &local mask. See function trie_amask_to_local() for details.
  *
  * There are four cases when we walk through a trie:
  *
@@ -65,8 +81,32 @@
  * - we are beyond the end of path (node length > &plen)
  * - we are still on path and keep walking (node length < &plen)
  *
- * The walking code in trie_match_prefix() is structured according to
- * these cases.
+ * The walking code in trie_match_net() is structured according to these cases.
+ *
+ * Iteration over prefixes in a trie can be done using TRIE_WALK() macro, or
+ * directly using trie_walk_init() and trie_walk_next() functions. The second
+ * approach allows suspending the iteration and continuing in it later.
+ * Prefixes are enumerated in the usual lexicographic order and may be
+ * restricted to a subset of the trie (all subnets of a specified prefix).
+ *
+ * Note that the trie walk does not reliably enumerate `implicit' prefixes
+ * defined by &low and &high fields in prefix patterns, it is supposed to be
+ * used on tries constructed from `explicit' prefixes (&low == &plen == &high
+ * in call to trie_add_prefix()).
+ *
+ * The trie walk has three basic state variables stored in the struct
+ * &f_trie_walk_state -- the current node in &stack[stack_pos], &accept_length
+ * for iteration over inter-node prefixes (non-branching prefixes on compressed
+ * path between the current node and its parent node, stored in the bitmap
+ * &accept of the current node) and &local_pos for iteration over intra-node
+ * prefixes (stored in the bitmap &local).
+ *
+ * The trie also supports longest-prefix-match query by trie_match_longest_ip4()
+ * and it can be extended to iteration over all covering prefixes for a given
+ * prefix (from longest to shortest) using TRIE_WALK_TO_ROOT_IP4() macro. There
+ * are also IPv6 versions (for practical reasons, these functions and macros are
+ * separate for IPv4 and IPv6). There is the same limitation to enumeration of
+ * `implicit' prefixes like with the previous TRIE_WALK() macro.
  */
 
 #include "nest/bird.h"
@@ -86,7 +126,10 @@
 #define ipa_mkmask(x) ip6_mkmask(x)
 #define ipa_masklen(x) ip6_masklen(&x)
 #define ipa_pxlen(x,y) ip6_pxlen(x,y)
-#define ipa_getbit(x,n) ip6_getbit(x,n)
+#define ipa_getbit(a,p) ip6_getbit(a,p)
+#define ipa_getbits(a,p,n) ip6_getbits(a,p,n)
+#define ipa_setbits(a,p,n) ip6_setbits(a,p,n)
+#define trie_local_mask(a,b,c) trie_local_mask6(a,b,c)
 
 #define ipt_from_ip4(x) _MI6(_I(x), 0, 0, 0)
 #define ipt_to_ip4(x) _MI4(_I0(x))
@@ -109,10 +152,11 @@ f_new_trie(linpool *lp, uint data_size)
 }
 
 static inline struct f_trie_node4 *
-new_node4(struct f_trie *t, int plen, ip4_addr paddr, ip4_addr pmask, ip4_addr amask)
+new_node4(struct f_trie *t, uint plen, uint local, ip4_addr paddr, ip4_addr pmask, ip4_addr amask)
 {
   struct f_trie_node4 *n = lp_allocz(t->lp, sizeof(struct f_trie_node4) + t->data_size);
   n->plen = plen;
+  n->local = local;
   n->addr = paddr;
   n->mask = pmask;
   n->accept = amask;
@@ -120,10 +164,11 @@ new_node4(struct f_trie *t, int plen, ip4_addr paddr, ip4_addr pmask, ip4_addr a
 }
 
 static inline struct f_trie_node6 *
-new_node6(struct f_trie *t, int plen, ip6_addr paddr, ip6_addr pmask, ip6_addr amask)
+new_node6(struct f_trie *t, uint plen, uint local, ip6_addr paddr, ip6_addr pmask, ip6_addr amask)
 {
   struct f_trie_node6 *n = lp_allocz(t->lp, sizeof(struct f_trie_node6) + t->data_size);
   n->plen = plen;
+  n->local = local;
   n->addr = paddr;
   n->mask = pmask;
   n->accept = amask;
@@ -131,24 +176,24 @@ new_node6(struct f_trie *t, int plen, ip6_addr paddr, ip6_addr pmask, ip6_addr a
 }
 
 static inline struct f_trie_node *
-new_node(struct f_trie *t, int plen, ip_addr paddr, ip_addr pmask, ip_addr amask)
+new_node(struct f_trie *t, uint plen, uint local, ip_addr paddr, ip_addr pmask, ip_addr amask)
 {
   if (t->ipv4)
-    return (struct f_trie_node *) new_node4(t, plen, ipt_to_ip4(paddr), ipt_to_ip4(pmask), ipt_to_ip4(amask));
+    return (struct f_trie_node *) new_node4(t, plen, local, ipt_to_ip4(paddr), ipt_to_ip4(pmask), ipt_to_ip4(amask));
   else
-    return (struct f_trie_node *) new_node6(t, plen, ipa_to_ip6(paddr), ipa_to_ip6(pmask), ipa_to_ip6(amask));
+    return (struct f_trie_node *) new_node6(t, plen, local, ipa_to_ip6(paddr), ipa_to_ip6(pmask), ipa_to_ip6(amask));
 }
 
 static inline void
 attach_node4(struct f_trie_node4 *parent, struct f_trie_node4 *child)
 {
-  parent->c[ip4_getbit(child->addr, parent->plen) ? 1 : 0] = child;
+  parent->c[ip4_getbits(child->addr, parent->plen, TRIE_STEP)] = child;
 }
 
 static inline void
 attach_node6(struct f_trie_node6 *parent, struct f_trie_node6 *child)
 {
-  parent->c[ip6_getbit(child->addr, parent->plen) ? 1 : 0] = child;
+  parent->c[ip6_getbits(child->addr, parent->plen, TRIE_STEP)] = child;
 }
 
 static inline void
@@ -160,10 +205,182 @@ attach_node(struct f_trie_node *parent, struct f_trie_node *child, int v4)
     attach_node6(&parent->v6, &child->v6);
 }
 
+
+/*
+ * Internal prefixes of a node a represented by the local bitmask, each bit for
+ * one prefix. Bit 0 is unused, Bit 1 is for the main prefix of the node,
+ * remaining bits correspond to subprefixes by this pattern:
+ *
+ *          1
+ *      2       3
+ *    4   5   6   7
+ *   8 9 A B C D E F
+ *
+ * E.g. for 10.0.0.0/8 node, the 10.64.0.0/10 would be position 5.
+ */
+
+/*
+ * Compute appropriate mask representing prefix px/plen in local bitmask of node
+ * with prefix length nlen. Assuming that nlen <= plen < (nlen + TRIE_STEP).
+ */
+static inline uint
+trie_local_mask4(ip4_addr px, uint plen, uint nlen)
+{
+  uint step = plen - nlen;
+  uint pos = (1u << step) + ip4_getbits(px, nlen, step);
+  return 1u << pos;
+}
+
+static inline uint
+trie_local_mask6(ip6_addr px, uint plen, uint nlen)
+{
+  uint step = plen - nlen;
+  uint pos = (1u << step) + ip6_getbits(px, nlen, step);
+  return 1u << pos;
+}
+
+/*
+ * Compute an appropriate local mask (for a node with prefix length nlen)
+ * representing prefixes of px that are accepted by amask and fall within the
+ * range associated with that node. Used for propagation of child accept mask
+ * to parent local mask.
+ */
+static inline uint
+trie_amask_to_local(ip_addr px, ip_addr amask, uint nlen)
+{
+  uint local = 0;
+
+  for (uint plen = MAX(nlen, 1); plen < (nlen + TRIE_STEP); plen++)
+    if (ipa_getbit(amask, plen - 1))
+      local |= trie_local_mask(px, plen, nlen);
+
+  return local;
+}
+
+/*
+ * Compute a bitmask representing a level of subprefixes (of the same length),
+ * using specified position as a root. E.g., level 2 from root position 3 would
+ * be bit positions C-F, returned as bitmask 0xf000.
+ */
+static inline uint
+trie_level_mask(uint pos, uint level)
+{
+  return ((1u << (1u << level)) - 1) << (pos << level);
+}
+
+
 #define GET_ADDR(N,F,X) ((X) ? ipt_from_ip4((N)->v4.F) : ipa_from_ip6((N)->v6.F))
 #define SET_ADDR(N,F,X,V) ({ if (X) (N)->v4.F =ipt_to_ip4(V); else (N)->v6.F =ipa_to_ip6(V); })
 
-#define GET_CHILD(N,F,X,I) ((X) ? (struct f_trie_node *) (N)->v4.c[I] : (struct f_trie_node *) (N)->v6.c[I])
+#define GET_LOCAL(N,X) ((X) ? (N)->v4.local : (N)->v6.local)
+#define ADD_LOCAL(N,X,V) ({ uint v_ = (V); if (X) (N)->v4.local |= v_; else (N)->v6.local |= v_; })
+
+#define GET_CHILD(N,X,I) ((X) ? (struct f_trie_node *) (N)->v4.c[I] : (struct f_trie_node *) (N)->v6.c[I])
+
+
+static void *
+trie_add_node(struct f_trie *t, uint plen, ip_addr px, uint local, uint l, uint h)
+{
+  uint l_ = l ? (l - 1) : 0;
+  ip_addr amask = (l_ < h) ? ipa_xor(ipa_mkmask(l_), ipa_mkmask(h)) : IPA_NONE;
+  ip_addr pmask = ipa_mkmask(plen);
+  ip_addr paddr = ipa_and(px, pmask);
+  struct f_trie_node *o = NULL;
+  struct f_trie_node *n = &t->root;
+  int v4 = t->ipv4;
+
+  /* Add all bits for each active level (0x0002 0x000c 0x00f0 0xff00) */
+  for (uint i = 0; i < TRIE_STEP; i++)
+    if ((l <= (plen + i)) && ((plen + i) <= h))
+      local |= trie_level_mask(1, i);
+
+  DBG("Insert node %I/%u (%I %x)\n", paddr, plen, amask, local);
+  while (n)
+    {
+      ip_addr naddr = GET_ADDR(n, addr, v4);
+      ip_addr nmask = GET_ADDR(n, mask, v4);
+      ip_addr accept = GET_ADDR(n, accept, v4);
+      ip_addr cmask = ipa_and(nmask, pmask);
+      uint nlen = v4 ? n->v4.plen : n->v6.plen;
+
+      DBG("Found node %I/%u (%I %x)\n",
+	  naddr, nlen, accept, v4 ? n->v4.local : n->v6.local);
+
+      if (ipa_compare(ipa_and(paddr, cmask), ipa_and(naddr, cmask)))
+        {
+	  /* We are out of path - we have to add branching node 'b'
+	     between node 'o' and node 'n', and attach new node 'a'
+	     as the other child of 'b'. */
+	  int blen = ROUND_DOWN_POW2(ipa_pxlen(paddr, naddr), TRIE_STEP);
+	  ip_addr bmask = ipa_mkmask(blen);
+	  ip_addr baddr = ipa_and(px, bmask);
+
+	  /* Merge accept masks from children to get accept mask for node 'b' */
+	  ip_addr baccm = ipa_and(ipa_or(amask, accept), bmask);
+	  uint bloc = trie_amask_to_local(naddr, accept, blen) |
+	              trie_amask_to_local(paddr, amask, blen);
+
+	  struct f_trie_node *a = new_node(t, plen, local, paddr, pmask, amask);
+	  struct f_trie_node *b = new_node(t, blen, bloc, baddr, bmask, baccm);
+	  attach_node(o, b, v4);
+	  attach_node(b, n, v4);
+	  attach_node(b, a, v4);
+	  t->prefix_count++;
+
+	  DBG("Case 1\n");
+	  return a;
+	}
+
+      if (plen < nlen)
+	{
+	  /* We add new node 'a' between node 'o' and node 'n' */
+	  amask = ipa_or(amask, ipa_and(accept, pmask));
+	  local |= trie_amask_to_local(naddr, accept, plen);
+	  struct f_trie_node *a = new_node(t, plen, local, paddr, pmask, amask);
+	  attach_node(o, a, v4);
+	  attach_node(a, n, v4);
+	  t->prefix_count++;
+
+	  DBG("Case 2\n");
+	  return a;
+	}
+
+      if (plen == nlen)
+	{
+	  /* We already found added node in trie. Just update accept and local mask */
+	  accept = ipa_or(accept, amask);
+	  SET_ADDR(n, accept, v4, accept);
+
+	  if ((GET_LOCAL(n, v4) & local) != local)
+	    t->prefix_count++;
+
+	  ADD_LOCAL(n, v4, local);
+
+	  DBG("Case 3\n");
+	  return n;
+	}
+
+      /* Update accept mask part M2 and go deeper */
+      accept = ipa_or(accept, ipa_and(amask, nmask));
+      SET_ADDR(n, accept, v4, accept);
+      ADD_LOCAL(n, v4, trie_amask_to_local(paddr, amask, nlen));
+
+      DBG("Step %u\n", ipa_getbits(paddr, nlen));
+
+      /* n->plen < plen and plen <= 32 (128) */
+      o = n;
+      n = GET_CHILD(n, v4, ipa_getbits(paddr, nlen, TRIE_STEP));
+    }
+
+  /* We add new tail node 'a' after node 'o' */
+  struct f_trie_node *a = new_node(t, plen, local, paddr, pmask, amask);
+  attach_node(o, a, v4);
+  t->prefix_count++;
+
+  DBG("Case 4\n");
+  return a;
+}
+
 /**
  * trie_add_prefix
  * @t: trie to add to
@@ -180,7 +397,6 @@ attach_node(struct f_trie_node *parent, struct f_trie_node *child, int v4)
  * a pointer to the root node is returned. Returns NULL when called with
  * mismatched IPv4/IPv6 net type.
  */
-
 void *
 trie_add_prefix(struct f_trie *t, const net_addr *net, uint l, uint h)
 {
@@ -190,9 +406,23 @@ trie_add_prefix(struct f_trie *t, const net_addr *net, uint l, uint h)
 
   switch (net->type)
   {
-  case NET_IP4: px = ipt_from_ip4(net4_prefix(net)); v4 = 1; break;
-  case NET_IP6: px = ipa_from_ip6(net6_prefix(net)); v4 = 0; break;
-  default: bug("invalid type");
+  case NET_IP4:
+  case NET_VPN4:
+  case NET_ROA4:
+    px = ipt_from_ip4(net4_prefix(net));
+    v4 = 1;
+    break;
+
+  case NET_IP6:
+  case NET_VPN6:
+  case NET_ROA6:
+  case NET_IP6_SADR:
+    px = ipa_from_ip6(net6_prefix(net));
+    v4 = 0;
+    break;
+
+  default:
+    bug("invalid type");
   }
 
   if (t->ipv4 != v4)
@@ -203,112 +433,97 @@ trie_add_prefix(struct f_trie *t, const net_addr *net, uint l, uint h)
       return NULL;
   }
 
+  DBG("\nInsert net %N (%u-%u)\n", net, l, h);
+
   if (l == 0)
     t->zero = 1;
-  else
-    l--;
 
   if (h < plen)
     plen = h;
 
-  ip_addr amask = ipa_xor(ipa_mkmask(l), ipa_mkmask(h));
-  ip_addr pmask = ipa_mkmask(plen);
-  ip_addr paddr = ipa_and(px, pmask);
-  struct f_trie_node *o = NULL;
-  struct f_trie_node *n = &t->root;
+  /* Primary node length, plen rounded down */
+  uint nlen = ROUND_DOWN_POW2(plen, TRIE_STEP);
 
-  while (n)
-    {
-      ip_addr naddr = GET_ADDR(n, addr, v4);
-      ip_addr nmask = GET_ADDR(n, mask, v4);
-      ip_addr accept = GET_ADDR(n, accept, v4);
-      ip_addr cmask = ipa_and(nmask, pmask);
-      uint nlen = v4 ? n->v4.plen : n->v6.plen;
+  if (plen == nlen)
+    return trie_add_node(t, nlen, px, 0, l,  h);
 
-      if (ipa_compare(ipa_and(paddr, cmask), ipa_and(naddr, cmask)))
-        {
-	  /* We are out of path - we have to add branching node 'b'
-	     between node 'o' and node 'n', and attach new node 'a'
-	     as the other child of 'b'. */
-	  int blen = ipa_pxlen(paddr, naddr);
-	  ip_addr bmask = ipa_mkmask(blen);
-	  ip_addr baddr = ipa_and(px, bmask);
+  /* Secondary node length, plen rouned up */
+  uint slen = nlen + TRIE_STEP;
+  void *node = NULL;
 
-	  /* Merge accept masks from children to get accept mask for node 'b' */
-	  ip_addr baccm = ipa_and(ipa_or(amask, accept), bmask);
+  /*
+   * For unaligned prefix lengths it is more complicated. We need to encode
+   * matching prefixes of lengths from l to h. There are three cases of lengths:
+   *
+   * 1) 0..nlen are encoded by the accept mask of the primary node
+   * 2) nlen..(slen-1) are encoded by the local mask of the primary node
+   * 3) slen..max are encoded in secondary nodes
+   */
 
-	  struct f_trie_node *a = new_node(t, plen, paddr, pmask, amask);
-	  struct f_trie_node *b = new_node(t, blen, baddr, bmask, baccm);
-	  attach_node(o, b, v4);
-	  attach_node(b, n, v4);
-	  attach_node(b, a, v4);
-	  return a;
-	}
+  if (l < slen)
+  {
+    uint local = 0;
 
-      if (plen < nlen)
-	{
-	  /* We add new node 'a' between node 'o' and node 'n' */
-	  amask = ipa_or(amask, ipa_and(accept, pmask));
-	  struct f_trie_node *a = new_node(t, plen, paddr, pmask, amask);
-	  attach_node(o, a, v4);
-	  attach_node(a, n, v4);
-	  return a;
-	}
+    /* Compute local bits for accepted nlen..(slen-1) prefixes */
+    for (uint i = 0; i < TRIE_STEP; i++)
+      if ((l <= (nlen + i)) && ((nlen + i) <= h))
+      {
+	uint pos = (1u << i) + ipa_getbits(px, nlen, i);
+	uint len = ((nlen + i) <= plen) ? 1 : (1u << (nlen + i - plen));
 
-      if (plen == nlen)
-	{
-	  /* We already found added node in trie. Just update accept mask */
-	  accept = ipa_or(accept, amask);
-	  SET_ADDR(n, accept, v4, accept);
-	  return n;
-	}
+	/* We need to fill 'len' bits starting at 'pos' position */
+	local |= ((1u << len) - 1) << pos;
+      }
 
-      /* Update accept mask part M2 and go deeper */
-      accept = ipa_or(accept, ipa_and(amask, nmask));
-      SET_ADDR(n, accept, v4, accept);
+    /* Add the primary node */
+    node = trie_add_node(t, nlen, px, local, l,  nlen);
+  }
 
-      /* n->plen < plen and plen <= 32 (128) */
-      o = n;
-      n = GET_CHILD(n, c, v4, ipa_getbit(paddr, nlen) ? 1 : 0);
-    }
+  if (slen <= h)
+  {
+    uint l2 = MAX(l, slen);
+    uint max = (1u << (slen - plen));
 
-  /* We add new tail node 'a' after node 'o' */
-  struct f_trie_node *a = new_node(t, plen, paddr, pmask, amask);
-  attach_node(o, a, v4);
+    /* Add secondary nodes */
+    for (uint i = 0; i < max; i++)
+      node = trie_add_node(t, slen, ipa_setbits(px,  slen - 1, i), 0, l2,  h);
+  }
 
-  return a;
+  return node;
 }
 
+
 static int
 trie_match_net4(const struct f_trie *t, ip4_addr px, uint plen)
 {
-  ip4_addr pmask = ip4_mkmask(plen);
-  ip4_addr paddr = ip4_and(px, pmask);
-
   if (plen == 0)
     return t->zero;
 
   int plentest = plen - 1;
+  uint nlen = ROUND_DOWN_POW2(plen, TRIE_STEP);
+  uint local = trie_local_mask4(px, plen, nlen);
   const struct f_trie_node4 *n = &t->root.v4;
 
   while (n)
   {
-    ip4_addr cmask = ip4_and(n->mask, pmask);
-
     /* We are out of path */
-    if (ip4_compare(ip4_and(paddr, cmask), ip4_and(n->addr, cmask)))
+    if (!ip4_prefix_equal(px, n->addr, MIN(plen, n->plen)))
       return 0;
 
+    /* Check local mask */
+    if ((n->plen == nlen) && (n->local & local))
+      return 1;
+
     /* Check accept mask */
     if (ip4_getbit(n->accept, plentest))
       return 1;
 
     /* We finished trie walk and still no match */
-    if (plen <= n->plen)
+    if (nlen <= n->plen)
       return 0;
 
     /* Choose children */
-    n =  n->c[(ip4_getbit(paddr, n->plen)) ? 1 : 0];
+    n =  n->c[ip4_getbits(px, n->plen, TRIE_STEP)];
   }
 
   return 0;
@@ -317,33 +532,34 @@ trie_match_net4(const struct f_trie *t, ip4_addr px, uint plen)
 static int
 trie_match_net6(const struct f_trie *t, ip6_addr px, uint plen)
 {
-  ip6_addr pmask = ip6_mkmask(plen);
-  ip6_addr paddr = ip6_and(px, pmask);
-
   if (plen == 0)
     return t->zero;
 
   int plentest = plen - 1;
+  uint nlen = ROUND_DOWN_POW2(plen, TRIE_STEP);
+  uint local = trie_local_mask6(px, plen, nlen);
   const struct f_trie_node6 *n = &t->root.v6;
 
   while (n)
   {
-    ip6_addr cmask = ip6_and(n->mask, pmask);
-
     /* We are out of path */
-    if (ip6_compare(ip6_and(paddr, cmask), ip6_and(n->addr, cmask)))
+    if (!ip6_prefix_equal(px, n->addr, MIN(plen, n->plen)))
       return 0;
 
+    /* Check local mask */
+    if ((n->plen == nlen) && (n->local & local))
+      return 1;
+
     /* Check accept mask */
     if (ip6_getbit(n->accept, plentest))
       return 1;
 
     /* We finished trie walk and still no match */
-    if (plen <= n->plen)
+    if (nlen <= n->plen)
       return 0;
 
     /* Choose children */
-    n =  n->c[(ip6_getbit(paddr, n->plen)) ? 1 : 0];
+    n =  n->c[ip6_getbits(px, n->plen, TRIE_STEP)];
   }
 
   return 0;
@@ -378,6 +594,412 @@ trie_match_net(const struct f_trie *t, const net_addr *n)
   }
 }
 
+
+/**
+ * trie_match_longest_ip4
+ * @t: trie
+ * @net: net address
+ * @dst: return value
+ * @found0: optional returned bitmask of found nodes
+ *
+ * Perform longest prefix match for the address @net and return the resulting
+ * prefix in the buffer @dst. The bitmask @found0 is used to report lengths of
+ * prefixes on the path from the root to the resulting prefix. E.g., if there is
+ * also a /20 shorter matching prefix, then 20-th bit is set in @found0. This
+ * can be used to enumerate all matching prefixes for the network @net using
+ * function trie_match_next_longest_ip4() or macro TRIE_WALK_TO_ROOT_IP4().
+ *
+ * This function assumes IPv4 trie, there is also an IPv6 variant. The @net
+ * argument is typed as net_addr_ip4, but would accept any IPv4-based net_addr,
+ * like net4_prefix(). Anyway, returned @dst is always net_addr_ip4.
+ *
+ * Result: 1 if a matching prefix was found, 0 if not.
+ */
+int
+trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr_ip4 *dst, ip4_addr *found0)
+{
+  ASSERT(t->ipv4);
+
+  const ip4_addr prefix = net->prefix;
+  const int pxlen = net->pxlen;
+
+  const struct f_trie_node4 *n = &t->root.v4;
+  int len = 0;
+
+  ip4_addr found = IP4_NONE;
+  int last = -1;
+
+  while (n)
+  {
+    /* We are out of path */
+    if (!ip4_prefix_equal(prefix, n->addr, MIN(pxlen, n->plen)))
+      goto done;
+
+    /* Check accept mask */
+    for (; len < n->plen; len++)
+    {
+      if (len > pxlen)
+	goto done;
+
+      if (ip4_getbit(n->accept, len - 1))
+      {
+	/* len is always < 32 due to len < n->plen */
+	ip4_setbit(&found, len);
+	last = len;
+      }
+    }
+
+    /* Special case for max length, there is only one valid local position */
+    if (len == IP4_MAX_PREFIX_LENGTH)
+    {
+      if (n->local & (1u << 1))
+	last = len;
+
+      goto done;
+    }
+
+    /* Check local mask */
+    for (int pos = 1; pos < (1 << TRIE_STEP); pos = 2 * pos + ip4_getbit(prefix, len), len++)
+    {
+      if (len > pxlen)
+	goto done;
+
+      if (n->local & (1u << pos))
+      {
+	/* len is always < 32 due to special case above */
+	ip4_setbit(&found, len);
+	last = len;
+      }
+    }
+
+    /* Choose child */
+    n = n->c[ip4_getbits(prefix, n->plen, TRIE_STEP)];
+  }
+
+done:
+  if (last < 0)
+    return 0;
+
+  *dst = NET_ADDR_IP4(ip4_and(prefix, ip4_mkmask(last)), last);
+
+  if (found0)
+    *found0 = found;
+
+  return 1;
+}
+
+
+/**
+ * trie_match_longest_ip6
+ * @t: trie
+ * @net: net address
+ * @dst: return value
+ * @found0: optional returned bitmask of found nodes
+ *
+ * Perform longest prefix match for the address @net and return the resulting
+ * prefix in the buffer @dst. The bitmask @found0 is used to report lengths of
+ * prefixes on the path from the root to the resulting prefix. E.g., if there is
+ * also a /20 shorter matching prefix, then 20-th bit is set in @found0. This
+ * can be used to enumerate all matching prefixes for the network @net using
+ * function trie_match_next_longest_ip6() or macro TRIE_WALK_TO_ROOT_IP6().
+ *
+ * This function assumes IPv6 trie, there is also an IPv4 variant. The @net
+ * argument is typed as net_addr_ip6, but would accept any IPv6-based net_addr,
+ * like net6_prefix(). Anyway, returned @dst is always net_addr_ip6.
+ *
+ * Result: 1 if a matching prefix was found, 0 if not.
+ */
+int
+trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr_ip6 *dst, ip6_addr *found0)
+{
+  ASSERT(!t->ipv4);
+
+  const ip6_addr prefix = net->prefix;
+  const int pxlen = net->pxlen;
+
+  const struct f_trie_node6 *n = &t->root.v6;
+  int len = 0;
+
+  ip6_addr found = IP6_NONE;
+  int last = -1;
+
+  while (n)
+  {
+    /* We are out of path */
+    if (!ip6_prefix_equal(prefix, n->addr, MIN(pxlen, n->plen)))
+      goto done;
+
+    /* Check accept mask */
+    for (; len < n->plen; len++)
+    {
+      if (len > pxlen)
+	goto done;
+
+      if (ip6_getbit(n->accept, len - 1))
+      {
+	/* len is always < 128 due to len < n->plen */
+	ip6_setbit(&found, len);
+	last = len;
+      }
+    }
+
+    /* Special case for max length, there is only one valid local position */
+    if (len == IP6_MAX_PREFIX_LENGTH)
+    {
+      if (n->local & (1u << 1))
+	last = len;
+
+      goto done;
+    }
+
+    /* Check local mask */
+    for (int pos = 1; pos < (1 << TRIE_STEP); pos = 2 * pos + ip6_getbit(prefix, len), len++)
+    {
+      if (len > pxlen)
+	goto done;
+
+      if (n->local & (1u << pos))
+      {
+	/* len is always < 128 due to special case above */
+	ip6_setbit(&found, len);
+	last = len;
+      }
+    }
+
+    /* Choose child */
+    n = n->c[ip6_getbits(prefix, n->plen, TRIE_STEP)];
+  }
+
+done:
+  if (last < 0)
+    return 0;
+
+  *dst = NET_ADDR_IP6(ip6_and(prefix, ip6_mkmask(last)), last);
+
+  if (found0)
+    *found0 = found;
+
+  return 1;
+}
+
+#define SAME_PREFIX(A,B,X,L) ((X) ? ip4_prefix_equal((A)->v4.addr, net4_prefix(B), (L)) : ip6_prefix_equal((A)->v6.addr, net6_prefix(B), (L)))
+#define GET_NET_BITS(N,X,A,B) ((X) ? ip4_getbits(net4_prefix(N), (A), (B)) : ip6_getbits(net6_prefix(N), (A), (B)))
+
+/**
+ * trie_walk_init
+ * @s: walk state
+ * @t: trie
+ * @net: optional subnet for walk
+ *
+ * Initialize walk state for subsequent walk through nodes of the trie @t by
+ * trie_walk_next(). The argument @net allows to restrict walk to given subnet,
+ * otherwise full walk over all nodes is used. This is done by finding node at
+ * or below @net and starting position in it.
+ */
+void
+trie_walk_init(struct f_trie_walk_state *s, const struct f_trie *t, const net_addr *net)
+{
+  *s = (struct f_trie_walk_state) {
+    .ipv4 = t->ipv4,
+    .accept_length = 0,
+    .start_pos = 1,
+    .local_pos = 1,
+    .stack_pos = 0,
+    .stack[0] = &t->root
+  };
+
+  if (!net)
+    return;
+
+  /* We want to find node of level at least plen */
+  int plen = ROUND_DOWN_POW2(net->pxlen, TRIE_STEP);
+  const struct f_trie_node *n = &t->root;
+  const int v4 = t->ipv4;
+
+  while (n)
+  {
+    int nlen = v4 ? n->v4.plen : n->v6.plen;
+
+    /* We are out of path */
+    if (!SAME_PREFIX(n, net, v4, MIN(net->pxlen, nlen)))
+      break;
+
+    /* We found final node */
+    if (nlen >= plen)
+    {
+      if (nlen == plen)
+      {
+	/* Find proper local_pos, while accept_length is not used */
+	int step = net->pxlen - plen;
+	s->start_pos = s->local_pos = (1u << step) + GET_NET_BITS(net, v4, plen, step);
+	s->accept_length = plen;
+      }
+      else
+      {
+	/* Start from pos 1 in local node, but first try accept mask */
+	s->accept_length = net->pxlen;
+      }
+
+      s->stack[0] = n;
+      return;
+    }
+
+    /* Choose child */
+    n = GET_CHILD(n, v4, GET_NET_BITS(net, v4, nlen, TRIE_STEP));
+  }
+
+  s->stack[0] = NULL;
+  return;
+}
+
+#define GET_ACCEPT_BIT(N,X,B) ((X) ? ip4_getbit((N)->v4.accept, (B)) : ip6_getbit((N)->v6.accept, (B)))
+#define GET_LOCAL_BIT(N,X,B) (((X) ? (N)->v4.local : (N)->v6.local) & (1u << (B)))
+
+/**
+ * trie_walk_next
+ * @s: walk state
+ * @net: return value
+ *
+ * Find the next prefix in the trie walk and return it in the buffer @net.
+ * Prefixes are walked in the usual lexicographic order and may be restricted
+ * to a subset of the trie during walk setup by trie_walk_init(). Note that the
+ * trie walk does not iterate reliably over 'implicit' prefixes defined by &low
+ * and &high fields in prefix patterns, it is supposed to be used on tries
+ * constructed from 'explicit' prefixes (&low == &plen == &high in call to
+ * trie_add_prefix()).
+ *
+ * Result: 1 if the next prefix was found, 0 for the end of walk.
+ */
+int
+trie_walk_next(struct f_trie_walk_state *s, net_addr *net)
+{
+  const struct f_trie_node *n = s->stack[s->stack_pos];
+  int len = s->accept_length;
+  int pos = s->local_pos;
+  int v4 = s->ipv4;
+
+  /*
+   * The walk has three basic state variables -- n, len and pos. In each node n,
+   * we first walk superprefixes (by len in &accept bitmask), and then we walk
+   * internal positions (by pos in &local bitmask). These positions are:
+   *
+   *          1
+   *      2       3
+   *    4   5   6   7
+   *   8 9 A B C D E F
+   *
+   * We walk them depth-first, including virtual positions 10-1F that are
+   * equivalent of position 1 in child nodes 0-F.
+   */
+
+  if (!n)
+  {
+    memset(net, 0, v4 ? sizeof(net_addr_ip4) : sizeof(net_addr_ip6));
+    return 0;
+  }
+
+next_node:;
+  /* Current node prefix length */
+  int nlen = v4 ? n->v4.plen : n->v6.plen;
+
+  /* First, check for accept prefix */
+  for (; len < nlen; len++)
+    if (GET_ACCEPT_BIT(n, v4, len - 1))
+    {
+      if (v4)
+	net_fill_ip4(net, ip4_and(n->v4.addr, ip4_mkmask(len)), len);
+      else
+	net_fill_ip6(net, ip6_and(n->v6.addr, ip6_mkmask(len)), len);
+
+      s->local_pos = pos;
+      s->accept_length = len + 1;
+      return 1;
+    }
+
+next_pos:
+  /* Bottom of this node */
+  if (pos >= (1 << TRIE_STEP))
+  {
+    const struct f_trie_node *child = GET_CHILD(n, v4, pos - (1 << TRIE_STEP));
+    int dir = 0;
+
+    /* No child node */
+    if (!child)
+    {
+      /* Step up until return from left child (pos is even) */
+      do
+      {
+	/* Step up from start node */
+	if ((s->stack_pos == 0) && (pos == s->start_pos))
+	{
+	  s->stack[0] = NULL;
+	  memset(net, 0, v4 ? sizeof(net_addr_ip4) : sizeof(net_addr_ip6));
+	  return 0;
+	}
+
+	/* Top of this node */
+	if (pos == 1)
+	{
+	  ASSERT(s->stack_pos);
+	  const struct f_trie_node *old = n;
+
+	  /* Move to parent node */
+	  s->stack_pos--;
+	  n = s->stack[s->stack_pos];
+	  nlen = v4 ? n->v4.plen : n->v6.plen;
+
+	  pos = v4 ?
+	    ip4_getbits(old->v4.addr, nlen, TRIE_STEP) :
+	    ip6_getbits(old->v6.addr, nlen, TRIE_STEP);
+	  pos += (1 << TRIE_STEP);
+	  len = nlen;
+
+	  ASSERT(GET_CHILD(n, v4, pos - (1 << TRIE_STEP)) == old);
+	}
+
+	/* Step up */
+	dir = pos % 2;
+	pos = pos / 2;
+      }
+      while (dir);
+
+      /* Continue with step down to the right child */
+      pos = 2 * pos + 1;
+      goto next_pos;
+    }
+
+    /* Move to child node */
+    pos = 1;
+    len = nlen + TRIE_STEP;
+
+    s->stack_pos++;
+    n = s->stack[s->stack_pos] = child;
+    goto next_node;
+  }
+
+  /* Check for local prefix */
+  if (GET_LOCAL_BIT(n, v4, pos))
+  {
+    /* Convert pos to address of local network */
+    int x = (pos >= 2) + (pos >= 4) + (pos >= 8);
+    int y = pos & ((1u << x) - 1);
+
+    if (v4)
+      net_fill_ip4(net, !x ? n->v4.addr : ip4_setbits(n->v4.addr, nlen + x - 1, y), nlen + x);
+    else
+      net_fill_ip6(net, !x ? n->v6.addr : ip6_setbits(n->v6.addr, nlen + x - 1, y), nlen + x);
+
+    s->local_pos = 2 * pos;
+    s->accept_length = len;
+    return 1;
+  }
+
+  /* Step down */
+  pos = 2 * pos;
+  goto next_pos;
+}
+
+
 static int
 trie_node_same4(const struct f_trie_node4 *t1, const struct f_trie_node4 *t2)
 {
@@ -392,7 +1014,11 @@ trie_node_same4(const struct f_trie_node4 *t1, const struct f_trie_node4 *t2)
       (! ip4_equal(t1->accept, t2->accept)))
     return 0;
 
-  return trie_node_same4(t1->c[0], t2->c[0]) && trie_node_same4(t1->c[1], t2->c[1]);
+  for (uint i = 0; i < (1 << TRIE_STEP); i++)
+    if (! trie_node_same4(t1->c[i], t2->c[i]))
+      return 0;
+
+  return 1;
 }
 
 static int
@@ -409,7 +1035,11 @@ trie_node_same6(const struct f_trie_node6 *t1, const struct f_trie_node6 *t2)
       (! ip6_equal(t1->accept, t2->accept)))
     return 0;
 
-  return trie_node_same6(t1->c[0], t2->c[0]) && trie_node_same6(t1->c[1], t2->c[1]);
+  for (uint i = 0; i < (1 << TRIE_STEP); i++)
+    if (! trie_node_same6(t1->c[i], t2->c[i]))
+      return 0;
+
+  return 1;
 }
 
 /**
@@ -431,30 +1061,70 @@ trie_same(const struct f_trie *t1, const struct f_trie *t2)
     return trie_node_same6(&t1->root.v6, &t2->root.v6);
 }
 
-static void
-trie_node_format4(const struct f_trie_node4 *t, buffer *buf)
-{
-  if (t == NULL)
-    return;
 
-  if (ip4_nonzero(t->accept))
-    buffer_print(buf, "%I4/%d{%I4}, ", t->addr, t->plen, t->accept);
-
-  trie_node_format4(t->c[0], buf);
-  trie_node_format4(t->c[1], buf);
-}
+static const u8 log2[16] = {0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3};
 
 static void
-trie_node_format6(const struct f_trie_node6 *t, buffer *buf)
+trie_node_format(const struct f_trie_node *n, buffer *buf, int v4)
 {
-  if (t == NULL)
+  if (n == NULL)
     return;
 
-  if (ip6_nonzero(t->accept))
-    buffer_print(buf, "%I6/%d{%I6}, ", t->addr, t->plen, t->accept);
+  if (v4)
+  {
+    if (ip4_nonzero(n->v4.accept))
+      buffer_print(buf, "%I4/%d{%I4}, ", n->v4.addr, n->v4.plen, n->v4.accept);
+  }
+  else
+  {
+    if (ip6_nonzero(n->v6.accept))
+      buffer_print(buf, "%I6/%d{%I6}, ", n->v6.addr, n->v6.plen, n->v6.accept);
+  }
 
-  trie_node_format6(t->c[0], buf);
-  trie_node_format6(t->c[1], buf);
+  int nlen = v4 ? n->v4.plen : n->v6.plen;
+  uint local = v4 ? n->v4.local : n->v6.local;
+
+  for (int i = (nlen ? 0 : 1); i < TRIE_STEP; i++)
+    if (GET_ACCEPT_BIT(n, v4, nlen + i - 1))
+      local &= ~trie_level_mask(1, i);
+
+  for (int pos = 2; local && (pos < (1 << TRIE_STEP)); pos++)
+    if (local & (1u << pos))
+    {
+      int lvl = log2[pos];
+      int plen = nlen + lvl;
+
+      int i;
+      for (i = 0; lvl + i < TRIE_STEP; i++)
+      {
+	uint lmask = trie_level_mask(pos, i);
+
+	if ((local & lmask) != lmask)
+	  break;
+
+	local &= ~lmask;
+      }
+
+      uint addr_bits = pos & ((1u << lvl) - 1);
+      uint accept_bits = (1u << i) - 1;
+      int h = plen + i - 1;
+
+      if (v4)
+      {
+	ip4_addr addr = ip4_setbits(n->v4.addr, plen - 1, addr_bits);
+	ip4_addr mask = ip4_setbits(IP4_NONE, h - 1, accept_bits);
+	buffer_print(buf, "%I4/%d{%I4}, ", addr, plen, mask);
+      }
+      else
+      {
+	ip6_addr addr = ip6_setbits(n->v6.addr, plen - 1, addr_bits);
+	ip6_addr mask = ip6_setbits(IP6_NONE, h - 1, accept_bits);
+	buffer_print(buf, "%I6/%d{%I6}, ", addr, plen, mask);
+      }
+    }
+
+  for (int i = 0; i < (1 << TRIE_STEP); i++)
+    trie_node_format(GET_CHILD(n, v4, i), buf, v4);
 }
 
 /**
@@ -472,10 +1142,7 @@ trie_format(const struct f_trie *t, buffer *buf)
   if (t->zero)
     buffer_print(buf, "%I/%d, ", t->ipv4 ? IPA_NONE4 : IPA_NONE6, 0);
 
-  if (t->ipv4)
-    trie_node_format4(&t->root.v4, buf);
-  else
-    trie_node_format6(&t->root.v6, buf);
+  trie_node_format(&t->root, buf, t->ipv4);
 
   if (buf->pos == buf->end)
     return;
diff --git a/filter/trie_test.c b/filter/trie_test.c
index b2b36716..cae86995 100644
--- a/filter/trie_test.c
+++ b/filter/trie_test.c
@@ -14,9 +14,12 @@
 #include "conf/conf.h"
 
 #define TESTS_NUM		10
-#define PREFIXES_NUM 		10
+#define PREFIXES_NUM 		32
 #define PREFIX_TESTS_NUM 	10000
+#define PREFIX_BENCH_NUM 	100000000
 
+#define TRIE_BUFFER_SIZE	1024
+#define TEST_BUFFER_SIZE	(1024*1024)
 #define BIG_BUFFER_SIZE		10000
 
 /* Wrapping structure for storing f_prefixes structures in list */
@@ -31,146 +34,860 @@ xrandom(u32 max)
   return (bt_random() % max);
 }
 
+static inline uint
+get_exp_random(void)
+{
+  uint r, n = 0;
+
+  for (r = bt_random(); r & 1; r = r >> 1)
+    n++;
+
+  return n;
+}
+
 static int
-is_prefix_included(list *prefixes, struct f_prefix *needle)
+compare_prefixes(const void *a, const void *b)
+{
+  return net_compare(&((const struct f_prefix *) a)->net,
+		     &((const struct f_prefix *) b)->net);
+}
+
+static inline int
+matching_ip4_nets(const net_addr_ip4 *a, const net_addr_ip4 *b)
+{
+  ip4_addr cmask = ip4_mkmask(MIN(a->pxlen, b->pxlen));
+  return ip4_compare(ip4_and(a->prefix, cmask), ip4_and(b->prefix, cmask)) == 0;
+}
+
+static inline int
+matching_ip6_nets(const net_addr_ip6 *a, const net_addr_ip6 *b)
+{
+  ip6_addr cmask = ip6_mkmask(MIN(a->pxlen, b->pxlen));
+  return ip6_compare(ip6_and(a->prefix, cmask), ip6_and(b->prefix, cmask)) == 0;
+}
+
+static inline int
+matching_nets(const net_addr *a, const net_addr *b)
+{
+  if (a->type != b->type)
+    return 0;
+
+  return (a->type == NET_IP4) ?
+    matching_ip4_nets((const net_addr_ip4 *) a, (const net_addr_ip4 *) b) :
+    matching_ip6_nets((const net_addr_ip6 *) a, (const net_addr_ip6 *) b);
+}
+
+static int
+is_prefix_included(list *prefixes, const net_addr *needle)
 {
   struct f_prefix_node *n;
   WALK_LIST(n, *prefixes)
-  {
-    ip6_addr cmask = ip6_mkmask(MIN(n->prefix.net.pxlen, needle->net.pxlen));
-
-    ip6_addr ip = net6_prefix(&n->prefix.net);
-    ip6_addr needle_ip = net6_prefix(&needle->net);
-
-    if ((ipa_compare(ipa_and(ip, cmask), ipa_and(needle_ip, cmask)) == 0) &&
-	(n->prefix.lo <= needle->net.pxlen) && (needle->net.pxlen <= n->prefix.hi))
+    if (matching_nets(&n->prefix.net, needle) &&
+	(n->prefix.lo <= needle->pxlen) && (needle->pxlen <= n->prefix.hi))
     {
-      bt_debug("FOUND\t" PRIip6 "/%d %d-%d\n", ARGip6(net6_prefix(&n->prefix.net)), n->prefix.net.pxlen, n->prefix.lo, n->prefix.hi);
+      char buf[64];
+      bt_format_net(buf, 64, &n->prefix.net);
+      bt_debug("FOUND %s %d-%d\n", buf, n->prefix.lo, n->prefix.hi);
+
       return 1; /* OK */
     }
-  }
+
   return 0; /* FAIL */
 }
 
-static struct f_prefix
-get_random_ip6_prefix(void)
+static void
+get_random_net(net_addr *net, int v6)
 {
-  struct f_prefix p;
-  u8 pxlen = xrandom(120)+8;
-  ip6_addr ip6 = ip6_build(bt_random(),bt_random(),bt_random(),bt_random());
-  net_addr_ip6 net6 = NET_ADDR_IP6(ip6, pxlen);
-
-  p.net = *((net_addr*) &net6);
-
-  if (bt_random() % 2)
+  if (!v6)
   {
-    p.lo = 0;
-    p.hi = p.net.pxlen;
+    uint pxlen = xrandom(24)+8;
+    ip4_addr ip4 = ip4_from_u32((u32) bt_random());
+    net_fill_ip4(net, ip4_and(ip4, ip4_mkmask(pxlen)), pxlen);
   }
   else
   {
-    p.lo = p.net.pxlen;
-    p.hi = net_max_prefix_length[p.net.type];
+    uint pxlen = xrandom(120)+8;
+    ip6_addr ip6 = ip6_build(bt_random(), bt_random(), bt_random(), bt_random());
+    net_fill_ip6(net, ip6_and(ip6, ip6_mkmask(pxlen)), pxlen);
   }
-
-  return p;
 }
 
 static void
-generate_random_ipv6_prefixes(list *prefixes)
+get_random_prefix(struct f_prefix *px, int v6, int tight)
 {
-  int i;
-  for (i = 0; i < PREFIXES_NUM; i++)
+  get_random_net(&px->net, v6);
+
+  if (tight)
   {
-    struct f_prefix f = get_random_ip6_prefix();
-
-    struct f_prefix_node *px = calloc(1, sizeof(struct f_prefix_node));
-    px->prefix = f;
-
-    bt_debug("ADD\t" PRIip6 "/%d %d-%d\n", ARGip6(net6_prefix(&px->prefix.net)), px->prefix.net.pxlen, px->prefix.lo, px->prefix.hi);
-    add_tail(prefixes, &px->n);
+    px->lo = px->hi = px->net.pxlen;
+  }
+  else if (bt_random() % 2)
+  {
+    px->lo = 0;
+    px->hi = px->net.pxlen;
+  }
+  else
+  {
+    px->lo = px->net.pxlen;
+    px->hi = net_max_prefix_length[px->net.type];
   }
 }
 
+static void
+get_random_ip4_subnet(net_addr_ip4 *net, const net_addr_ip4 *src, int pxlen)
+{
+  *net = NET_ADDR_IP4(ip4_and(src->prefix, ip4_mkmask(pxlen)), pxlen);
+
+  if (pxlen > src->pxlen)
+  {
+    ip4_addr rnd = ip4_from_u32((u32) bt_random());
+    ip4_addr mask = ip4_xor(ip4_mkmask(src->pxlen), ip4_mkmask(pxlen));
+    net->prefix = ip4_or(net->prefix, ip4_and(rnd, mask));
+  }
+}
+
+static void
+get_random_ip6_subnet(net_addr_ip6 *net, const net_addr_ip6 *src, int pxlen)
+{
+  *net = NET_ADDR_IP6(ip6_and(src->prefix, ip6_mkmask(pxlen)), pxlen);
+
+  if (pxlen > src->pxlen)
+  {
+    ip6_addr rnd = ip6_build(bt_random(), bt_random(), bt_random(), bt_random());
+    ip6_addr mask = ip6_xor(ip6_mkmask(src->pxlen), ip6_mkmask(pxlen));
+    net->prefix = ip6_or(net->prefix, ip6_and(rnd, mask));
+  }
+}
+
+static void
+get_random_subnet(net_addr *net, const net_addr *src, int pxlen)
+{
+  if (src->type == NET_IP4)
+    get_random_ip4_subnet((net_addr_ip4 *) net, (const net_addr_ip4 *) src, pxlen);
+  else
+    get_random_ip6_subnet((net_addr_ip6 *) net, (const net_addr_ip6 *) src, pxlen);
+}
+
+static void
+get_inner_net(net_addr *net, const struct f_prefix *src)
+{
+  int pxlen, step;
+
+  if (bt_random() % 2)
+  {
+    step = get_exp_random();
+    step = MIN(step, src->hi - src->lo);
+    pxlen = (bt_random() % 2) ? (src->lo + step) : (src->hi - step);
+  }
+  else
+    pxlen = src->lo + bt_random() % (src->hi - src->lo + 1);
+
+  get_random_subnet(net, &src->net, pxlen);
+}
+
+static void
+swap_random_bits_ip4(net_addr_ip4 *net, int num)
+{
+  for (int i = 0; i < num; i++)
+  {
+    ip4_addr swap = IP4_NONE;
+    ip4_setbit(&swap, bt_random() % net->pxlen);
+    net->prefix = ip4_xor(net->prefix, swap);
+  }
+}
+
+static void
+swap_random_bits_ip6(net_addr_ip6 *net, int num)
+{
+  for (int i = 0; i < num; i++)
+  {
+    ip6_addr swap = IP6_NONE;
+    ip6_setbit(&swap, bt_random() % net->pxlen);
+    net->prefix = ip6_xor(net->prefix, swap);
+  }
+}
+
+static void
+swap_random_bits(net_addr *net, int num)
+{
+  if (net->type == NET_IP4)
+    swap_random_bits_ip4((net_addr_ip4 *) net, num);
+  else
+    swap_random_bits_ip6((net_addr_ip6 *) net, num);
+}
+
+static void
+get_outer_net(net_addr *net, const struct f_prefix *src)
+{
+  int pxlen, step;
+  int inside = 0;
+  int max = net_max_prefix_length[src->net.type];
+
+  if ((src->lo > 0) && (bt_random() % 3))
+  {
+    step = 1 + get_exp_random();
+    step = MIN(step, src->lo);
+    pxlen = src->lo - step;
+  }
+  else if ((src->hi < max) && (bt_random() % 2))
+  {
+    step = 1 + get_exp_random();
+    step = MIN(step, max - src->hi);
+    pxlen = src->hi + step;
+  }
+  else
+  {
+    pxlen = src->lo + bt_random() % (src->hi - src->lo + 1);
+    inside = 1;
+  }
+
+  get_random_subnet(net, &src->net, pxlen);
+
+  /* Perhaps swap some bits in prefix */
+  if ((net->pxlen > 0) && (inside || (bt_random() % 4)))
+    swap_random_bits(net, 1 + get_exp_random());
+}
+
+static list *
+make_random_prefix_list(linpool *lp, int num, int v6, int tight)
+{
+  list *prefixes = lp_allocz(lp, sizeof(struct f_prefix_node));
+  init_list(prefixes);
+
+  for (int i = 0; i < num; i++)
+  {
+    struct f_prefix_node *px = lp_allocz(lp, sizeof(struct f_prefix_node));
+    get_random_prefix(&px->prefix, v6, tight);
+    add_tail(prefixes, &px->n);
+
+    char buf[64];
+    bt_format_net(buf, 64, &px->prefix.net);
+    bt_debug("ADD %s{%d,%d}\n", buf, px->prefix.lo, px->prefix.hi);
+  }
+
+  return prefixes;
+}
+
+static struct f_trie *
+make_trie_from_prefix_list(linpool *lp, list *prefixes)
+{
+  struct f_trie *trie = f_new_trie(lp, 0);
+
+  struct f_prefix_node *n;
+  WALK_LIST(n, *prefixes)
+    trie_add_prefix(trie, &n->prefix.net, n->prefix.lo, n->prefix.hi);
+
+  return trie;
+}
+
+/*
+ * Read sequence of prefixes from file handle and return prefix list.
+ * Each prefix is on one line, sequence terminated by empty line or eof.
+ * Arg @plus means prefix should include all longer ones.
+ */
+static list *
+read_prefix_list(linpool *lp, FILE *f, int v6, int plus)
+{
+  ASSERT(!v6);
+
+  uint a0, a1, a2, a3, pl;
+  char s[32];
+  int n;
+
+  list *pxlist = lp_allocz(lp, sizeof(struct f_prefix_node));
+  init_list(pxlist);
+
+  errno = 0;
+  while (fgets(s, 32, f))
+  {
+    if (s[0] == '\n')
+      return pxlist;
+
+    n = sscanf(s, "%u.%u.%u.%u/%u", &a0, &a1, &a2, &a3, &pl);
+
+    if (n != 5)
+      bt_abort_msg("Invalid content of trie_data");
+
+    struct f_prefix_node *px = lp_allocz(lp, sizeof(struct f_prefix_node));
+    net_fill_ip4(&px->prefix.net, ip4_build(a0, a1, a2, a3), pl);
+    px->prefix.lo = pl;
+    px->prefix.hi = plus ? IP4_MAX_PREFIX_LENGTH : pl;
+    add_tail(pxlist, &px->n);
+
+    char buf[64];
+    bt_format_net(buf, 64, &px->prefix.net);
+    bt_debug("ADD %s{%d,%d}\n", buf, px->prefix.lo, px->prefix.hi);
+  }
+
+  bt_syscall(errno, "fgets()");
+  return EMPTY_LIST(*pxlist) ? NULL : pxlist;
+}
+
+/*
+ * Open file, read multiple sequences of prefixes from it. Fill @data with
+ * prefix lists and @trie with generated tries. Return number of sequences /
+ * tries. Use separate linpool @lp0 for prefix lists and @lp1 for tries.
+ * Arg @plus means prefix should include all longer ones.
+ */
 static int
-t_match_net(void)
+read_prefix_file(const char *filename, int plus,
+		 linpool *lp0, linpool *lp1,
+		 list *data[], struct f_trie *trie[])
+{
+  FILE *f = fopen(filename, "r");
+  bt_syscall(!f, "fopen(%s)", filename);
+
+  int n = 0;
+  list *pxlist;
+  while (pxlist = read_prefix_list(lp0, f, 0, plus))
+  {
+    data[n] = pxlist;
+    trie[n] = make_trie_from_prefix_list(lp1, pxlist);
+    bt_debug("NEXT\n");
+    n++;
+  }
+
+  fclose(f);
+  bt_debug("DONE reading %d tries\n", n);
+
+  return n;
+}
+
+/*
+ * Select random subset of @dn prefixes from prefix list @src of length @sn,
+ * and store them to buffer @dst (of size @dn). Prefixes may be chosen multiple
+ * times. Randomize order of prefixes in @dst buffer.
+ */
+static void
+select_random_prefix_subset(list *src[], net_addr dst[], int sn, int dn)
+{
+  int pn = 0;
+
+  if (!dn)
+    return;
+
+  /* Compute total prefix number */
+  for (int i = 0; i < sn; i++)
+    pn += list_length(src[i]);
+
+  /* Change of selecting a prefix */
+  int rnd = (pn / dn) + 10;
+  int n = 0;
+
+  /* Iterate indefinitely over src array */
+  for (int i = 0; 1; i++, i = (i < sn) ? i : 0)
+  {
+    struct f_prefix_node *px;
+    WALK_LIST(px, *src[i])
+    {
+      if (xrandom(rnd) != 0)
+	continue;
+
+      net_copy(&dst[n], &px->prefix.net);
+      n++;
+
+      /* We have enough */
+      if (n == dn)
+	goto done;
+    }
+  }
+
+done:
+  /* Shuffle networks */
+  for (int i = 0; i < dn; i++)
+  {
+    int j = xrandom(dn);
+
+    if (i == j)
+      continue;
+
+    net_addr tmp;
+    net_copy(&tmp, &dst[i]);
+    net_copy(&dst[i], &dst[j]);
+    net_copy(&dst[j], &tmp);
+  }
+}
+
+/* Fill @dst buffer with @dn randomly generated /32 prefixes */
+static void
+make_random_addresses(net_addr dst[], int dn)
+{
+  for (int i = 0; i < dn; i++)
+    net_fill_ip4(&dst[i], ip4_from_u32((u32) bt_random()), IP4_MAX_PREFIX_LENGTH);
+}
+
+static void
+test_match_net(list *prefixes, struct f_trie *trie, const net_addr *net)
+{
+  char buf[64];
+  bt_format_net(buf, 64, net);
+  bt_debug("TEST %s\n", buf);
+
+  int should_be = is_prefix_included(prefixes, net);
+  int is_there  = trie_match_net(trie, net);
+
+  bt_assert_msg(should_be == is_there, "Prefix %s %s match", buf,
+		(should_be ? "should" : "should not"));
+}
+
+static int
+t_match_random_net(void)
 {
   bt_bird_init();
   bt_config_parse(BT_CONFIG_SIMPLE);
 
-  uint round;
-  for (round = 0; round < TESTS_NUM; round++)
+  int v6 = 0;
+  linpool *lp = lp_new_default(&root_pool);
+  for (int round = 0; round < TESTS_NUM; round++)
   {
-    list prefixes; /* of structs f_extended_prefix */
-    init_list(&prefixes);
-    struct f_trie *trie = f_new_trie(config->mem, 0);
+    list *prefixes = make_random_prefix_list(lp, PREFIXES_NUM, v6, 0);
+    struct f_trie *trie = make_trie_from_prefix_list(lp, prefixes);
 
-    generate_random_ipv6_prefixes(&prefixes);
-    struct f_prefix_node *n;
-    WALK_LIST(n, prefixes)
+    for (int i = 0; i < PREFIX_TESTS_NUM; i++)
     {
-      trie_add_prefix(trie, &n->prefix.net, n->prefix.lo, n->prefix.hi);
+      net_addr net;
+      get_random_net(&net, v6);
+      test_match_net(prefixes, trie, &net);
     }
 
-    int i;
-    for (i = 0; i < PREFIX_TESTS_NUM; i++)
-    {
-      struct f_prefix f = get_random_ip6_prefix();
-      bt_debug("TEST\t" PRIip6 "/%d\n", ARGip6(net6_prefix(&f.net)), f.net.pxlen);
-
-      int should_be = is_prefix_included(&prefixes, &f);
-      int is_there  = trie_match_net(trie, &f.net);
-      bt_assert_msg(should_be == is_there, "Prefix " PRIip6 "/%d %s", ARGip6(net6_prefix(&f.net)), f.net.pxlen, (should_be ? "should be found in trie" : "should not be found in trie"));
-    }
-
-    struct f_prefix_node *nxt;
-    WALK_LIST_DELSAFE(n, nxt, prefixes)
-    {
-      free(n);
-    }
+    v6 = !v6;
+    lp_flush(lp);
   }
 
   bt_bird_cleanup();
   return 1;
 }
 
+static int
+t_match_inner_net(void)
+{
+  bt_bird_init();
+  bt_config_parse(BT_CONFIG_SIMPLE);
+
+  int v6 = 0;
+  linpool *lp = lp_new_default(&root_pool);
+  for (int round = 0; round < TESTS_NUM; round++)
+  {
+    list *prefixes = make_random_prefix_list(lp, PREFIXES_NUM, v6, 0);
+    struct f_trie *trie = make_trie_from_prefix_list(lp, prefixes);
+
+    struct f_prefix_node *n = HEAD(*prefixes);
+    for (int i = 0; i < PREFIX_TESTS_NUM; i++)
+    {
+      net_addr net;
+      get_inner_net(&net, &n->prefix);
+      test_match_net(prefixes, trie, &net);
+
+      n = NODE_VALID(NODE_NEXT(n)) ? NODE_NEXT(n) : HEAD(*prefixes);
+    }
+
+    v6 = !v6;
+    lp_flush(lp);
+  }
+
+  bt_bird_cleanup();
+  return 1;
+}
+
+static int
+t_match_outer_net(void)
+{
+  bt_bird_init();
+  bt_config_parse(BT_CONFIG_SIMPLE);
+
+  int v6 = 0;
+  linpool *lp = lp_new_default(&root_pool);
+  for (int round = 0; round < TESTS_NUM; round++)
+  {
+    list *prefixes = make_random_prefix_list(lp, PREFIXES_NUM, v6, 0);
+    struct f_trie *trie = make_trie_from_prefix_list(lp, prefixes);
+
+    struct f_prefix_node *n = HEAD(*prefixes);
+    for (int i = 0; i < PREFIX_TESTS_NUM; i++)
+    {
+      net_addr net;
+      get_outer_net(&net, &n->prefix);
+      test_match_net(prefixes, trie, &net);
+
+      n = NODE_VALID(NODE_NEXT(n)) ? NODE_NEXT(n) : HEAD(*prefixes);
+    }
+
+    v6 = !v6;
+    lp_flush(lp);
+  }
+
+  v6 = !v6;
+  bt_bird_cleanup();
+  return 1;
+}
+
+/*
+ * Read prefixes from @filename, build set of tries, prepare test data and do
+ * PREFIX_BENCH_NUM trie lookups. With @plus = 0, use random subset of known
+ * prefixes as test data, with @plus = 1, use randomly generated /32 prefixes
+ * as test data.
+ */
+static int
+benchmark_trie_dataset(const char *filename, int plus)
+{
+  int n = 0;
+  linpool *lp0 = lp_new_default(&root_pool);
+  linpool *lp1 = lp_new_default(&root_pool);
+  list *data[TRIE_BUFFER_SIZE];
+  struct f_trie *trie[TRIE_BUFFER_SIZE];
+  net_addr *nets;
+
+  bt_reset_suite_case_timer();
+  bt_log_suite_case_result(1, "Reading %s", filename, n);
+  n = read_prefix_file(filename, plus, lp0, lp1, data, trie);
+  bt_log_suite_case_result(1, "Read prefix data, %d lists, ", n);
+
+  size_t trie_size = rmemsize(lp1).effective * 1000 / (1024*1024);
+  bt_log_suite_case_result(1, "Trie size %u.%03u MB",
+			   (uint) (trie_size / 1000), (uint) (trie_size % 1000));
+
+  int t = PREFIX_BENCH_NUM / n;
+  int tb = MIN(t, TEST_BUFFER_SIZE);
+  nets = lp_alloc(lp0, tb * sizeof(net_addr));
+
+  if (!plus)
+    select_random_prefix_subset(data, nets, n, tb);
+  else
+    make_random_addresses(nets, tb);
+
+  bt_log_suite_case_result(1, "Make test data, %d (%d) tests", t, tb);
+  bt_reset_suite_case_timer();
+
+  /*
+  int match = 0;
+  for (int i = 0; i < t; i++)
+    for (int j = 0; j < n; j++)
+      test_match_net(data[j], trie[j], &nets[i]);
+  */
+
+  int match = 0;
+  for (int i = 0; i < t; i++)
+    for (int j = 0; j < n; j++)
+      if (trie_match_net(trie[j], &nets[i % TEST_BUFFER_SIZE]))
+	match++;
+
+  bt_log_suite_case_result(1, "Matching done, %d / %d matches", match, t * n);
+
+  rfree(lp0);
+  rfree(lp1);
+
+  return 1;
+}
+
+static int UNUSED
+t_bench_trie_datasets_subset(void)
+{
+  bt_bird_init();
+  bt_config_parse(BT_CONFIG_SIMPLE);
+
+  /* Specific datasets, not included */
+  benchmark_trie_dataset("trie-data-bgp-1", 0);
+  benchmark_trie_dataset("trie-data-bgp-10", 0);
+  benchmark_trie_dataset("trie-data-bgp-100", 0);
+  benchmark_trie_dataset("trie-data-bgp-1000", 0);
+
+  bt_bird_cleanup();
+
+  return 1;
+}
+
+static int UNUSED
+t_bench_trie_datasets_random(void)
+{
+  bt_bird_init();
+  bt_config_parse(BT_CONFIG_SIMPLE);
+
+  /* Specific datasets, not included */
+  benchmark_trie_dataset("trie-data-bgp-1", 1);
+  benchmark_trie_dataset("trie-data-bgp-10", 1);
+  benchmark_trie_dataset("trie-data-bgp-100", 1);
+  benchmark_trie_dataset("trie-data-bgp-1000", 1);
+
+  bt_bird_cleanup();
+
+  return 1;
+}
+
+
 static int
 t_trie_same(void)
 {
   bt_bird_init();
   bt_config_parse(BT_CONFIG_SIMPLE);
 
-  int round;
-  for (round = 0; round < TESTS_NUM*4; round++)
+  int v6 = 0;
+  linpool *lp = lp_new_default(&root_pool);
+  for (int round = 0; round < TESTS_NUM*4; round++)
   {
-    struct f_trie * trie1 = f_new_trie(config->mem, 0);
-    struct f_trie * trie2 = f_new_trie(config->mem, 0);
-
-    list prefixes; /* a list of f_extended_prefix structures */
-    init_list(&prefixes);
-    int i;
-    for (i = 0; i < 100; i++)
-      generate_random_ipv6_prefixes(&prefixes);
+    list *prefixes = make_random_prefix_list(lp, 100 * PREFIXES_NUM, v6, 0);
+    struct f_trie *trie1 = f_new_trie(lp, 0);
+    struct f_trie *trie2 = f_new_trie(lp, 0);
 
     struct f_prefix_node *n;
-    WALK_LIST(n, prefixes)
-    {
+    WALK_LIST(n, *prefixes)
       trie_add_prefix(trie1, &n->prefix.net, n->prefix.lo, n->prefix.hi);
-    }
-    WALK_LIST_BACKWARDS(n, prefixes)
-    {
+
+    WALK_LIST_BACKWARDS(n, *prefixes)
       trie_add_prefix(trie2, &n->prefix.net, n->prefix.lo, n->prefix.hi);
-    }
 
     bt_assert(trie_same(trie1, trie2));
 
-    struct f_prefix_node *nxt;
-    WALK_LIST_DELSAFE(n, nxt, prefixes)
-    {
-      free(n);
-    }
+    v6 = !v6;
+    lp_flush(lp);
   }
 
+  bt_bird_cleanup();
+  return 1;
+}
+
+static inline void
+log_networks(const net_addr *a, const net_addr *b)
+{
+  if (bt_verbose >= BT_VERBOSE_ABSOLUTELY_ALL)
+  {
+    char buf0[64];
+    char buf1[64];
+    bt_format_net(buf0, 64, a);
+    bt_format_net(buf1, 64, b);
+    bt_debug("Found %s expected %s\n", buf0, buf1);
+  }
+}
+
+static int
+t_trie_walk(void)
+{
+  bt_bird_init();
+  bt_config_parse(BT_CONFIG_SIMPLE);
+
+  linpool *lp = lp_new_default(&root_pool);
+  for (int round = 0; round < TESTS_NUM*8; round++)
+  {
+    int level = round / TESTS_NUM;
+    int v6 = level % 2;
+    int num = PREFIXES_NUM * (int[]){1, 10, 100, 1000}[level / 2];
+    int pos = 0, end = 0;
+    list *prefixes = make_random_prefix_list(lp, num, v6, 1);
+    struct f_trie *trie = make_trie_from_prefix_list(lp, prefixes);
+    struct f_prefix *pxset = malloc((num + 1) * sizeof(struct f_prefix));
+
+    struct f_prefix_node *n;
+    WALK_LIST(n, *prefixes)
+      pxset[pos++] = n->prefix;
+    memset(&pxset[pos], 0, sizeof (struct f_prefix));
+
+    qsort(pxset, num, sizeof(struct f_prefix), compare_prefixes);
+
+
+    /* Full walk */
+    bt_debug("Full walk (round %d, %d nets)\n", round, num);
+
+    pos = 0;
+    uint pxc = 0;
+    TRIE_WALK(trie, net, NULL)
+    {
+      log_networks(&net, &pxset[pos].net);
+      bt_assert(net_equal(&net, &pxset[pos].net));
+
+      /* Skip possible duplicates */
+      while (net_equal(&pxset[pos].net, &pxset[pos + 1].net))
+	pos++;
+
+      pos++;
+      pxc++;
+    }
+    TRIE_WALK_END;
+
+    bt_assert(pos == num);
+    bt_assert(pxc == trie->prefix_count);
+    bt_debug("Full walk done\n");
+
+
+    /* Prepare net for subnet walk - start with random prefix */
+    pos = bt_random() % num;
+    end = pos + (int[]){2, 2, 3, 4}[level / 2];
+    end = MIN(end, num);
+
+    struct f_prefix from = pxset[pos];
+
+    /* Find a common superprefix to several subsequent prefixes */
+    for (; pos < end; pos++)
+    {
+      if (net_equal(&from.net, &pxset[pos].net))
+	continue;
+
+      int common = !v6 ?
+	ip4_pxlen(net4_prefix(&from.net), net4_prefix(&pxset[pos].net)) :
+	ip6_pxlen(net6_prefix(&from.net), net6_prefix(&pxset[pos].net));
+      from.net.pxlen = MIN(from.net.pxlen, common);
+
+      if (!v6)
+	((net_addr_ip4 *) &from.net)->prefix =
+	  ip4_and(net4_prefix(&from.net), net4_prefix(&pxset[pos].net));
+      else
+	((net_addr_ip6 *) &from.net)->prefix =
+	  ip6_and(net6_prefix(&from.net), net6_prefix(&pxset[pos].net));
+    }
+
+    /* Fix irrelevant bits */
+    if (!v6)
+      ((net_addr_ip4 *) &from.net)->prefix =
+	ip4_and(net4_prefix(&from.net), ip4_mkmask(net4_pxlen(&from.net)));
+    else
+      ((net_addr_ip6 *) &from.net)->prefix =
+	ip6_and(net6_prefix(&from.net), ip6_mkmask(net6_pxlen(&from.net)));
+
+
+    /* Find initial position for final prefix */
+    for (pos = 0; pos < num; pos++)
+      if (compare_prefixes(&pxset[pos], &from) >= 0)
+	break;
+
+    int p0 = pos;
+    char buf0[64];
+    bt_format_net(buf0, 64, &from.net);
+    bt_debug("Subnet walk for %s (round %d, %d nets)\n", buf0, round, num);
+
+    /* Subnet walk */
+    TRIE_WALK(trie, net, &from.net)
+    {
+      log_networks(&net, &pxset[pos].net);
+      bt_assert(net_equal(&net, &pxset[pos].net));
+      bt_assert(net_in_netX(&net, &from.net));
+
+      /* Skip possible duplicates */
+      while (net_equal(&pxset[pos].net, &pxset[pos + 1].net))
+	pos++;
+
+      pos++;
+    }
+    TRIE_WALK_END;
+
+    bt_assert((pos == num) || !net_in_netX(&pxset[pos].net, &from.net));
+    bt_debug("Subnet walk done for %s (found %d nets)\n", buf0, pos - p0);
+
+    lp_flush(lp);
+  }
+
+  bt_bird_cleanup();
+  return 1;
+}
+
+static int
+find_covering_nets(struct f_prefix *prefixes, int num, const net_addr *net, net_addr *found)
+{
+  struct f_prefix key;
+  net_addr *n = &key.net;
+  int found_num = 0;
+
+  net_copy(n, net);
+
+  while (1)
+  {
+    struct f_prefix *px =
+      bsearch(&key, prefixes, num, sizeof(struct f_prefix), compare_prefixes);
+
+    if (px)
+    {
+      net_copy(&found[found_num], n);
+      found_num++;
+    }
+
+    if (n->pxlen == 0)
+      return found_num;
+
+    n->pxlen--;
+
+    if (n->type == NET_IP4)
+      ip4_clrbit(&((net_addr_ip4 *) n)->prefix, n->pxlen);
+    else
+      ip6_clrbit(&((net_addr_ip6 *) n)->prefix, n->pxlen);
+  }
+}
+
+static int
+t_trie_walk_to_root(void)
+{
+  bt_bird_init();
+  bt_config_parse(BT_CONFIG_SIMPLE);
+
+  linpool *lp = lp_new_default(&root_pool);
+  for (int round = 0; round < TESTS_NUM * 4; round++)
+  {
+    int level = round / TESTS_NUM;
+    int v6 = level % 2;
+    int num = PREFIXES_NUM  * (int[]){32, 512}[level / 2];
+    int pos = 0;
+    int st = 0, sn = 0, sm = 0;
+
+    list *prefixes = make_random_prefix_list(lp, num, v6, 1);
+    struct f_trie *trie = make_trie_from_prefix_list(lp, prefixes);
+    struct f_prefix *pxset = malloc((num + 1) * sizeof(struct f_prefix));
+
+    struct f_prefix_node *pxn;
+    WALK_LIST(pxn, *prefixes)
+      pxset[pos++] = pxn->prefix;
+    memset(&pxset[pos], 0, sizeof (struct f_prefix));
+
+    qsort(pxset, num, sizeof(struct f_prefix), compare_prefixes);
+
+    int i;
+    for (i = 0; i < (PREFIX_TESTS_NUM / 10); i++)
+    {
+      net_addr from;
+      get_random_net(&from, v6);
+
+      net_addr found[129];
+      int found_num = find_covering_nets(pxset, num, &from, found);
+      int n = 0;
+
+      if (bt_verbose >= BT_VERBOSE_ABSOLUTELY_ALL)
+      {
+	char buf[64];
+	bt_format_net(buf, 64, &from);
+	bt_debug("Lookup for %s (expect %d)\n", buf, found_num);
+      }
+
+      /* Walk to root, separate for IPv4 and IPv6 */
+      if (!v6)
+      {
+	TRIE_WALK_TO_ROOT_IP4(trie, (net_addr_ip4 *) &from, net)
+	{
+	  log_networks((net_addr *) &net, &found[n]);
+	  bt_assert((n < found_num) && net_equal((net_addr *) &net, &found[n]));
+	  n++;
+	}
+	TRIE_WALK_TO_ROOT_END;
+      }
+      else
+      {
+	TRIE_WALK_TO_ROOT_IP6(trie, (net_addr_ip6 *) &from, net)
+	{
+	  log_networks((net_addr *) &net, &found[n]);
+	  bt_assert((n < found_num) && net_equal((net_addr *) &net, &found[n]));
+	  n++;
+	}
+	TRIE_WALK_TO_ROOT_END;
+      }
+
+      bt_assert(n == found_num);
+
+      /* Stats */
+      st += n;
+      sn += !!n;
+      sm = MAX(sm, n);
+    }
+
+    bt_debug("Success in %d / %d, sum %d, max %d\n", sn, i, st, sm);
+
+    lp_flush(lp);
+  }
+
+  bt_bird_cleanup();
   return 1;
 }
 
@@ -179,8 +896,15 @@ main(int argc, char *argv[])
 {
   bt_init(argc, argv);
 
-  bt_test_suite(t_match_net, "Testing random prefix matching");
+  bt_test_suite(t_match_random_net, "Testing random prefix matching");
+  bt_test_suite(t_match_inner_net, "Testing random inner prefix matching");
+  bt_test_suite(t_match_outer_net, "Testing random outer prefix matching");
   bt_test_suite(t_trie_same, "A trie filled forward should be same with a trie filled backward.");
+  bt_test_suite(t_trie_walk, "Testing TRIE_WALK() on random tries");
+  bt_test_suite(t_trie_walk_to_root, "Testing TRIE_WALK_TO_ROOT() on random tries");
+
+  // bt_test_suite(t_bench_trie_datasets_subset, "Benchmark tries from datasets by random subset of nets");
+  // bt_test_suite(t_bench_trie_datasets_random, "Benchmark tries from datasets by generated addresses");
 
   return bt_exit_value();
 }
diff --git a/lib/birdlib.h b/lib/birdlib.h
index 431b7c0d..81d4908a 100644
--- a/lib/birdlib.h
+++ b/lib/birdlib.h
@@ -32,6 +32,9 @@ struct align_probe { char x; long int y; };
 #define MAX(a,b) MAX_(a,b)
 #endif
 
+#define ROUND_DOWN_POW2(a,b)  ((a) & ~((b)-1))
+#define ROUND_UP_POW2(a,b)  (((a)+((b)-1)) & ~((b)-1))
+
 #define U64(c) UINT64_C(c)
 #define ABS(a)   ((a)>=0 ? (a) : -(a))
 #define DELTA(a,b) (((a)>=(b))?(a)-(b):(b)-(a))
diff --git a/lib/ip.h b/lib/ip.h
index 5b179acb..9eef2e16 100644
--- a/lib/ip.h
+++ b/lib/ip.h
@@ -279,11 +279,35 @@ static inline uint ip6_pxlen(ip6_addr a, ip6_addr b)
   return 32 * i + 31 - u32_log2(a.addr[i] ^ b.addr[i]);
 }
 
+static inline int ip4_prefix_equal(ip4_addr a, ip4_addr b, uint n)
+{
+  return (_I(a) ^ _I(b)) < ((u64) 1 << (32 - n));
+}
+
+static inline int ip6_prefix_equal(ip6_addr a, ip6_addr b, uint n)
+{
+  uint n0 = n / 32;
+  uint n1 = n % 32;
+
+  return
+    ((n0 <= 0) || (_I0(a) == _I0(b))) &&
+    ((n0 <= 1) || (_I1(a) == _I1(b))) &&
+    ((n0 <= 2) || (_I2(a) == _I2(b))) &&
+    ((n0 <= 3) || (_I3(a) == _I3(b))) &&
+    (!n1 || ((a.addr[n0] ^ b.addr[n0]) < (1u << (32 - n1))));
+}
+
 static inline u32 ip4_getbit(ip4_addr a, uint pos)
-{ return _I(a) & (0x80000000 >> pos); }
+{ return (_I(a) >> (31 - pos)) & 1; }
+
+static inline u32 ip4_getbits(ip4_addr a, uint pos, uint n)
+{ return (_I(a) >> ((32 - n) - pos)) & ((1u << n) - 1); }
 
 static inline u32 ip6_getbit(ip6_addr a, uint pos)
-{ return a.addr[pos / 32] & (0x80000000 >> (pos % 32)); }
+{ return (a.addr[pos / 32] >> (31 - (pos % 32))) & 0x1; }
+
+static inline u32 ip6_getbits(ip6_addr a, uint pos, uint n)
+{ return (a.addr[pos / 32] >> ((32 - n) - (pos % 32))) & ((1u << n) - 1); }
 
 static inline u32 ip4_setbit(ip4_addr *a, uint pos)
 { return _I(*a) |= (0x80000000 >> pos); }
@@ -297,6 +321,13 @@ static inline u32 ip4_clrbit(ip4_addr *a, uint pos)
 static inline u32 ip6_clrbit(ip6_addr *a, uint pos)
 { return a->addr[pos / 32] &= ~(0x80000000 >> (pos % 32)); }
 
+static inline ip4_addr ip4_setbits(ip4_addr a, uint pos, uint val)
+{ _I(a) |= val << (31 - pos); return a; }
+
+static inline ip6_addr ip6_setbits(ip6_addr a, uint pos, uint val)
+{ a.addr[pos / 32] |= val << (31 - pos % 32); return a; }
+
+
 static inline ip4_addr ip4_opposite_m1(ip4_addr a)
 { return _MI4(_I(a) ^ 1); }
 
diff --git a/lib/ip_test.c b/lib/ip_test.c
index 36d10d68..eee0a427 100644
--- a/lib/ip_test.c
+++ b/lib/ip_test.c
@@ -167,6 +167,70 @@ t_ip6_ntop(void)
   return bt_assert_batch(test_vectors, test_ipa_ntop, bt_fmt_ipa, bt_fmt_str);
 }
 
+static int
+t_ip4_prefix_equal(void)
+{
+  bt_assert( ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x1234ffff), 16));
+  bt_assert(!ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x1234ffff), 17));
+  bt_assert( ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x12345000), 21));
+  bt_assert(!ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x12345000), 22));
+
+  bt_assert( ip4_prefix_equal(ip4_from_u32(0x00000000), ip4_from_u32(0xffffffff),  0));
+  bt_assert( ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x12345678),  0));
+
+  bt_assert( ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x12345678),  32));
+  bt_assert(!ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x12345679),  32));
+  bt_assert(!ip4_prefix_equal(ip4_from_u32(0x12345678), ip4_from_u32(0x92345678),  32));
+
+  return 1;
+}
+
+static int
+t_ip6_prefix_equal(void)
+{
+  bt_assert( ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x1234ffff, 0xfefefefe, 0xdcdcdcdc),
+			      48));
+
+  bt_assert(!ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x1234ffff, 0xfefefefe, 0xdcdcdcdc),
+			      49));
+
+  bt_assert(!ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20020db8, 0x12345678, 0xfefefefe, 0xdcdcdcdc),
+			      48));
+
+  bt_assert( ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x12345678, 0xfefefefe, 0xdcdcdcdc),
+			      64));
+
+  bt_assert(!ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x1234567e, 0xfefefefe, 0xdcdcdcdc),
+			      64));
+
+  bt_assert( ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20002020),
+			      ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      106));
+
+  bt_assert(!ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20002020),
+			      ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      107));
+
+  bt_assert( ip6_prefix_equal(ip6_build(0xfeef0db8, 0x87654321, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x12345678, 0xfefefefe, 0xdcdcdcdc),
+			      0));
+
+  bt_assert( ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      128));
+
+  bt_assert(!ip6_prefix_equal(ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202020),
+			      ip6_build(0x20010db8, 0x12345678, 0x10101010, 0x20202021),
+			      128));
+
+  return 1;
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -176,6 +240,8 @@ main(int argc, char *argv[])
   bt_test_suite(t_ip6_pton, "Converting IPv6 string to ip6_addr struct");
   bt_test_suite(t_ip4_ntop, "Converting ip4_addr struct to IPv4 string");
   bt_test_suite(t_ip6_ntop, "Converting ip6_addr struct to IPv6 string");
+  bt_test_suite(t_ip4_prefix_equal, "Testing ip4_prefix_equal()");
+  bt_test_suite(t_ip6_prefix_equal, "Testing ip6_prefix_equal()");
 
   return bt_exit_value();
 }
diff --git a/lib/net.h b/lib/net.h
index 8eb4c7b9..9f4a00ad 100644
--- a/lib/net.h
+++ b/lib/net.h
@@ -38,6 +38,7 @@
 
 #define NB_IP		(NB_IP4 | NB_IP6)
 #define NB_VPN		(NB_VPN4 | NB_VPN6)
+#define NB_ROA		(NB_ROA4 | NB_ROA6)
 #define NB_FLOW		(NB_FLOW4 | NB_FLOW6)
 #define NB_DEST		(NB_IP | NB_IP6_SADR | NB_VPN | NB_MPLS)
 #define NB_ANY		0xffffffff
diff --git a/nest/config.Y b/nest/config.Y
index 7ead8589..72bc7930 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -17,6 +17,7 @@ CF_HDR
 
 CF_DEFINES
 
+static struct rtable_config *this_table;
 static struct proto_config *this_proto;
 static struct channel_config *this_channel;
 static struct iface_patt *this_ipatt;
@@ -117,13 +118,14 @@ CF_KEYWORDS(IPV4, IPV6, VPN4, VPN6, ROA4, ROA6, FLOW4, FLOW6, SADR, MPLS)
 CF_KEYWORDS(RECEIVE, LIMIT, ACTION, WARN, BLOCK, RESTART, DISABLE, KEEP, FILTERED, RPKI)
 CF_KEYWORDS(PASSWORD, KEY, FROM, PASSIVE, TO, ID, EVENTS, PACKETS, PROTOCOLS, CHANNELS, INTERFACES)
 CF_KEYWORDS(ALGORITHM, KEYED, HMAC, MD5, SHA1, SHA256, SHA384, SHA512, BLAKE2S128, BLAKE2S256, BLAKE2B256, BLAKE2B512)
-CF_KEYWORDS(PRIMARY, STATS, COUNT, BY, FOR, COMMANDS, PREEXPORT, NOEXPORT, EXPORTED, GENERATE)
-CF_KEYWORDS(BGP, PASSWORDS, DESCRIPTION, SORTED)
+CF_KEYWORDS(PRIMARY, STATS, COUNT, BY, FOR, IN, COMMANDS, PREEXPORT, NOEXPORT, EXPORTED, GENERATE)
+CF_KEYWORDS(BGP, PASSWORDS, DESCRIPTION)
 CF_KEYWORDS(RELOAD, IN, OUT, MRTDUMP, MESSAGES, RESTRICT, MEMORY, IGP_METRIC, CLASS, DSCP)
 CF_KEYWORDS(TIMEFORMAT, ISO, SHORT, LONG, ROUTE, PROTOCOL, BASE, LOG, S, MS, US)
 CF_KEYWORDS(GRACEFUL, RESTART, WAIT, MAX, FLUSH, AS)
 CF_KEYWORDS(MIN, IDLE, RX, TX, INTERVAL, MULTIPLIER, PASSIVE)
 CF_KEYWORDS(CHECK, LINK)
+CF_KEYWORDS(SORTED, TRIE, MIN, MAX, SETTLE, TIME)
 
 /* For r_args_channel */
 CF_KEYWORDS(IPV4, IPV4_MC, IPV4_MPLS, IPV6, IPV6_MC, IPV6_MPLS, IPV6_SADR, VPN4, VPN4_MC, VPN4_MPLS, VPN6, VPN6_MC, VPN6_MPLS, ROA4, ROA6, FLOW4, FLOW6, MPLS, PRI, SEC)
@@ -141,7 +143,7 @@ CF_ENUM_PX(T_ENUM_AF, AF_, AFI_, IPV4, IPV6)
 %type <s> optproto
 %type <ra> r_args
 %type <sd> sym_args
-%type <i> proto_start echo_mask echo_size debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_mode limit_action net_type table_sorted tos password_algorithm
+%type <i> proto_start echo_mask echo_size debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_mode limit_action net_type tos password_algorithm
 %type <ps> proto_patt proto_patt2
 %type <cc> channel_start proto_channel
 %type <cl> limit_spec
@@ -206,16 +208,37 @@ CF_ENUM(T_ENUM_NETTYPE, NET_, IP4, IP6, VPN4, VPN6, ROA4, ROA6, FLOW4, FLOW6, IP
 
 conf: table ;
 
-table_sorted:
-	  { $$ = 0; }
- | SORTED { $$ = 1; }
+table: table_start table_sorted table_opt_list ;
+
+table_start: net_type TABLE symbol {
+   this_table = rt_new_table($3, $1);
+   }
  ;
 
-table: net_type TABLE symbol table_sorted {
-   struct rtable_config *cf;
-   cf = rt_new_table($3, $1);
-   cf->sorted = $4;
+table_sorted:
+   /* empty */
+ | SORTED { this_table->sorted = 1; }
+ ;
+
+table_opt:
+   SORTED bool { this_table->sorted = $2; }
+ | TRIE bool {
+     if (!net_val_match(this_table->addr_type, NB_IP | NB_VPN | NB_ROA | NB_IP6_SADR))
+       cf_error("Trie option not supported for %s table", net_label[this_table->addr_type]);
+     this_table->trie_used = $2;
    }
+ | MIN SETTLE TIME expr_us { this_table->min_settle_time = $4; }
+ | MAX SETTLE TIME expr_us { this_table->max_settle_time = $4; }
+ ;
+
+table_opts:
+   /* empty */
+ | table_opts table_opt ';'
+ ;
+
+table_opt_list:
+   /* empty */
+ | '{' table_opts '}'
  ;
 
 
@@ -621,14 +644,22 @@ r_args:
      $$ = $1;
      if ($$->addr) cf_error("Only one prefix expected");
      $$->addr = $2;
+     $$->addr_mode = RSD_ADDR_EQUAL;
    }
  | r_args FOR r_args_for {
      $$ = $1;
      if ($$->addr) cf_error("Only one prefix expected");
-     $$->show_for = 1;
      $$->addr = $3;
+     $$->addr_mode = RSD_ADDR_FOR;
    }
- | r_args TABLE CF_SYM_KNOWN {
+ | r_args IN net_any {
+     $$ = $1;
+     if ($$->addr) cf_error("Only one prefix expected");
+     if (!net_type_match($3, NB_IP)) cf_error("Only IP networks accepted for 'in' argument");
+     $$->addr = $3;
+     $$->addr_mode = RSD_ADDR_IN;
+   }
+| r_args TABLE CF_SYM_KNOWN {
      cf_assert_symbol($3, SYM_TABLE);
      $$ = $1;
      rt_show_add_table($$, $3->table->table);
diff --git a/nest/route.h b/nest/route.h
index f5fc9e31..7930058a 100644
--- a/nest/route.h
+++ b/nest/route.h
@@ -20,7 +20,10 @@ struct proto;
 struct rte_src;
 struct symbol;
 struct timer;
+struct fib;
 struct filter;
+struct f_trie;
+struct f_trie_walk_state;
 struct cli;
 
 /*
@@ -49,7 +52,7 @@ struct fib_iterator {			/* See lib/slists.h for an explanation */
   uint hash;
 };
 
-typedef void (*fib_init_fn)(void *);
+typedef void (*fib_init_fn)(struct fib *, void *);
 
 struct fib {
   pool *fib_pool;			/* Pool holding all our data */
@@ -149,6 +152,7 @@ struct rtable_config {
   int gc_min_time;			/* Minimum time between two consecutive GC runs */
   byte sorted;				/* Routes of network are sorted according to rte_better() */
   byte internal;			/* Internal table of a protocol */
+  byte trie_used;			/* Rtable has attached trie */
   btime min_settle_time;		/* Minimum settle time for notifications */
   btime max_settle_time;		/* Maximum settle time for notifications */
 };
@@ -158,6 +162,7 @@ typedef struct rtable {
   node n;				/* Node in list of all tables */
   pool *rp;				/* Resource pool to allocate everything from, including itself */
   struct fib fib;
+  struct f_trie *trie;			/* Trie of prefixes defined in fib */
   char *name;				/* Name of this table */
   list channels;			/* List of attached channels (struct channel) */
   uint addr_type;			/* Type of address data stored in table (NET_*) */
@@ -180,13 +185,20 @@ typedef struct rtable {
   btime gc_time;			/* Time of last GC */
   int gc_counter;			/* Number of operations since last GC */
   byte prune_state;			/* Table prune state, 1 -> scheduled, 2-> running */
+  byte prune_trie;			/* Prune prefix trie during next table prune */
   byte hcu_scheduled;			/* Hostcache update is scheduled */
   byte nhu_state;			/* Next Hop Update state */
   struct fib_iterator prune_fit;	/* Rtable prune FIB iterator */
   struct fib_iterator nhu_fit;		/* Next Hop Update FIB iterator */
+  struct f_trie *trie_new;		/* New prefix trie defined during pruning */
+  struct f_trie *trie_old;		/* Old prefix trie waiting to be freed */
+  u32 trie_lock_count;			/* Prefix trie locked by walks */
+  u32 trie_old_lock_count;		/* Old prefix trie locked by walks */
 
   list subscribers;			/* Subscribers for notifications */
   struct timer *settle_timer;		/* Settle time for notifications */
+  list flowspec_links;			/* List of flowspec links, src for NET_IPx and dst for NET_FLOWx */
+  struct f_trie *flowspec_trie;		/* Trie for evaluation of flowspec notifications */
 } rtable;
 
 struct rt_subscription {
@@ -196,6 +208,13 @@ struct rt_subscription {
   void *data;
 };
 
+struct rt_flowspec_link {
+  node n;
+  rtable *src;
+  rtable *dst;
+  u32 uc;
+};
+
 #define NHU_CLEAN	0
 #define NHU_SCHEDULED	1
 #define NHU_RUNNING	2
@@ -262,6 +281,7 @@ typedef struct rte {
     struct {
       u8 suppressed;			/* Used for deterministic MED comparison */
       s8 stale;				/* Route is LLGR_STALE, -1 if unknown */
+      struct rtable *base_table;	/* Base table for Flowspec validation */
     } bgp;
 #endif
 #ifdef CONFIG_BABEL
@@ -315,8 +335,12 @@ void rt_preconfig(struct config *);
 void rt_commit(struct config *new, struct config *old);
 void rt_lock_table(rtable *);
 void rt_unlock_table(rtable *);
+struct f_trie * rt_lock_trie(rtable *tab);
+void rt_unlock_trie(rtable *tab, struct f_trie *trie);
 void rt_subscribe(rtable *tab, struct rt_subscription *s);
 void rt_unsubscribe(struct rt_subscription *s);
+void rt_flowspec_link(rtable *src, rtable *dst);
+void rt_flowspec_unlink(rtable *src, rtable *dst);
 rtable *rt_setup(pool *, struct rtable_config *);
 static inline void rt_shutdown(rtable *r) { rfree(r->rp); }
 
@@ -324,7 +348,8 @@ static inline net *net_find(rtable *tab, const net_addr *addr) { return (net *)
 static inline net *net_find_valid(rtable *tab, const net_addr *addr)
 { net *n = net_find(tab, addr); return (n && rte_is_valid(n->routes)) ? n : NULL; }
 static inline net *net_get(rtable *tab, const net_addr *addr) { return (net *) fib_get(&tab->fib, addr); }
-void *net_route(rtable *tab, const net_addr *n);
+net *net_get(rtable *tab, const net_addr *addr);
+net *net_route(rtable *tab, const net_addr *n);
 int net_roa_check(rtable *tab, const net_addr *n, u32 asn);
 rte *rte_find(net *net, struct rte_src *src);
 rte *rte_get_temp(struct rta *);
@@ -356,6 +381,18 @@ void rt_prune_sync(rtable *t, int all);
 int rte_update_out(struct channel *c, const net_addr *n, rte *new, rte *old0, int refeed);
 struct rtable_config *rt_new_table(struct symbol *s, uint addr_type);
 
+static inline int rt_is_ip(rtable *tab)
+{ return (tab->addr_type == NET_IP4) || (tab->addr_type == NET_IP6); }
+
+static inline int rt_is_vpn(rtable *tab)
+{ return (tab->addr_type == NET_VPN4) || (tab->addr_type == NET_VPN6); }
+
+static inline int rt_is_roa(rtable *tab)
+{ return (tab->addr_type == NET_ROA4) || (tab->addr_type == NET_ROA6); }
+
+static inline int rt_is_flow(rtable *tab)
+{ return (tab->addr_type == NET_FLOW4) || (tab->addr_type == NET_FLOW6); }
+
 
 /* Default limit for ECMP next hops, defined in sysdep code */
 extern const int rt_default_ecmp;
@@ -372,6 +409,8 @@ struct rt_show_data {
   struct rt_show_data_rtable *tab;	/* Iterator over table list */
   struct rt_show_data_rtable *last_table; /* Last table in output */
   struct fib_iterator fit;		/* Iterator over networks in table */
+  struct f_trie_walk_state *walk_state;	/* Iterator over networks in trie */
+  struct f_trie *walk_lock;		/* Locked trie for walking */
   int verbose, tables_defined_by;
   const struct filter *filter;
   struct proto *show_protocol;
@@ -379,9 +418,10 @@ struct rt_show_data {
   struct channel *export_channel;
   struct config *running_on_config;
   struct krt_proto *kernel;
-  int export_mode, primary_only, filtered, stats, show_for;
+  int export_mode, addr_mode, primary_only, filtered, stats;
 
   int table_open;			/* Iteration (fit) is open */
+  int trie_walk;			/* Current table is iterated using trie */
   int net_counter, rt_counter, show_counter, table_counter;
   int net_counter_last, rt_counter_last, show_counter_last;
 };
@@ -398,6 +438,11 @@ struct rt_show_data_rtable * rt_show_add_table(struct rt_show_data *d, rtable *t
 #define RSD_TDB_SET	  0x1		/* internal: show empty tables */
 #define RSD_TDB_NMN	  0x2		/* internal: need matching net */
 
+/* Value of addr_mode */
+#define RSD_ADDR_EQUAL	1		/* Exact query - show route <addr> */
+#define RSD_ADDR_FOR	2		/* Longest prefix match - show route for <addr> */
+#define RSD_ADDR_IN	3		/* Interval query - show route in <addr> */
+
 /* Value of export_mode in struct rt_show_data */
 #define RSEM_NONE	0		/* Export mode not used */
 #define RSEM_PREEXPORT	1		/* Routes ready for export, before filtering */
@@ -718,6 +763,9 @@ rta_set_recursive_next_hop(rtable *dep, rta *a, rtable *tab, ip_addr gw, ip_addr
 static inline void rt_lock_hostentry(struct hostentry *he) { if (he) he->uc++; }
 static inline void rt_unlock_hostentry(struct hostentry *he) { if (he) he->uc--; }
 
+int rt_flowspec_check(rtable *tab_ip, rtable *tab_flow, const net_addr *n, rta *a, int interior);
+
+
 /*
  *	Default protocol preferences
  */
diff --git a/nest/rt-fib.c b/nest/rt-fib.c
index a7f70371..1690a8f6 100644
--- a/nest/rt-fib.c
+++ b/nest/rt-fib.c
@@ -331,7 +331,7 @@ fib_get(struct fib *f, const net_addr *a)
 
   memset(b, 0, f->node_offset);
   if (f->init)
-    f->init(b);
+    f->init(f, b);
 
   if (f->entries++ > f->entries_max)
     fib_rehash(f, HASH_HI_STEP);
diff --git a/nest/rt-show.c b/nest/rt-show.c
index 7691878d..f8b7ba51 100644
--- a/nest/rt-show.c
+++ b/nest/rt-show.c
@@ -15,6 +15,7 @@
 #include "nest/cli.h"
 #include "nest/iface.h"
 #include "filter/filter.h"
+#include "filter/data.h"
 #include "sysdep/unix/krt.h"
 
 static void
@@ -110,10 +111,9 @@ rt_show_net(struct cli *c, net *n, struct rt_show_data *d)
   ASSUME(!d->export_mode || ec);
 
   int first = 1;
+  int first_show = 1;
   int pass = 0;
 
-  bsnprintf(ia, sizeof(ia), "%N", n->n.addr);
-
   for (e = n->routes; e; e = e->next)
     {
       if (rte_is_filtered(e) != d->filtered)
@@ -187,10 +187,17 @@ rt_show_net(struct cli *c, net *n, struct rt_show_data *d)
 	goto skip;
 
       if (d->stats < 2)
+      {
+	if (first_show)
+	  net_format(n->n.addr, ia, sizeof(ia));
+	else
+	  ia[0] = 0;
+
 	rt_show_rte(c, ia, e, d, (e->net->routes == ee));
+	first_show = 0;
+      }
 
       d->show_counter++;
-      ia[0] = 0;
 
     skip:
       if (e != ee)
@@ -212,9 +219,12 @@ rt_show_cleanup(struct cli *c)
   struct rt_show_data_rtable *tab;
 
   /* Unlink the iterator */
-  if (d->table_open)
+  if (d->table_open && !d->trie_walk)
     fit_get(&d->tab->table->fib, &d->fit);
 
+  if (d->walk_lock)
+    rt_unlock_trie(d->tab->table, d->walk_lock);
+
   /* Unlock referenced tables */
   WALK_LIST(tab, d->tables)
     rt_unlock_table(tab->table);
@@ -224,12 +234,13 @@ static void
 rt_show_cont(struct cli *c)
 {
   struct rt_show_data *d = c->rover;
+  struct rtable *tab = d->tab->table;
 #ifdef DEBUGGING
   unsigned max = 4;
 #else
   unsigned max = 64;
 #endif
-  struct fib *fib = &d->tab->table->fib;
+  struct fib *fib = &tab->fib;
   struct fib_iterator *it = &d->fit;
 
   if (d->running_on_config && (d->running_on_config != config))
@@ -240,7 +251,22 @@ rt_show_cont(struct cli *c)
 
   if (!d->table_open)
   {
-    FIB_ITERATE_INIT(&d->fit, &d->tab->table->fib);
+    /* We use either trie-based walk or fib-based walk */
+    d->trie_walk = tab->trie &&
+      (d->addr_mode == RSD_ADDR_IN) &&
+      net_val_match(tab->addr_type, NB_IP);
+
+    if (d->trie_walk && !d->walk_state)
+      d->walk_state = lp_allocz(c->parser_pool, sizeof (struct f_trie_walk_state));
+
+    if (d->trie_walk)
+    {
+      d->walk_lock = rt_lock_trie(tab);
+      trie_walk_init(d->walk_state, tab->trie, d->addr);
+    }
+    else
+      FIB_ITERATE_INIT(&d->fit, &tab->fib);
+
     d->table_open = 1;
     d->table_counter++;
     d->kernel = rt_show_get_kernel(d);
@@ -253,16 +279,44 @@ rt_show_cont(struct cli *c)
       rt_show_table(c, d);
   }
 
-  FIB_ITERATE_START(fib, it, net, n)
+  if (d->trie_walk)
   {
-    if (!max--)
+    /* Trie-based walk */
+    net_addr addr;
+    while (trie_walk_next(d->walk_state, &addr))
     {
-      FIB_ITERATE_PUT(it);
-      return;
+      net *n = net_find(tab, &addr);
+      if (!n)
+	continue;
+
+      rt_show_net(c, n, d);
+
+      if (!--max)
+	return;
     }
-    rt_show_net(c, n, d);
+
+    rt_unlock_trie(tab, d->walk_lock);
+    d->walk_lock = NULL;
+  }
+  else
+  {
+    /* fib-based walk */
+    FIB_ITERATE_START(fib, it, net, n)
+    {
+      if ((d->addr_mode == RSD_ADDR_IN) && (!net_in_netX(n->n.addr, d->addr)))
+	goto next;
+
+      if (!max--)
+      {
+	FIB_ITERATE_PUT(it);
+	return;
+      }
+      rt_show_net(c, n, d);
+
+    next:;
+    }
+    FIB_ITERATE_END;
   }
-  FIB_ITERATE_END;
 
   if (d->stats)
   {
@@ -271,7 +325,7 @@ rt_show_cont(struct cli *c)
 
     cli_printf(c, -1007, "%d of %d routes for %d networks in table %s",
 	       d->show_counter - d->show_counter_last, d->rt_counter - d->rt_counter_last,
-	       d->net_counter - d->net_counter_last, d->tab->table->name);
+	       d->net_counter - d->net_counter_last, tab->name);
   }
 
   d->kernel = NULL;
@@ -402,7 +456,7 @@ rt_show(struct rt_show_data *d)
 
   rt_show_prepare_tables(d);
 
-  if (!d->addr)
+  if (!d->addr || (d->addr_mode == RSD_ADDR_IN))
   {
     WALK_LIST(tab, d->tables)
       rt_lock_table(tab->table);
@@ -420,7 +474,7 @@ rt_show(struct rt_show_data *d)
       d->tab = tab;
       d->kernel = rt_show_get_kernel(d);
 
-      if (d->show_for)
+      if (d->addr_mode == RSD_ADDR_FOR)
 	n = net_route(tab->table, d->addr);
       else
 	n = net_find(tab->table, d->addr);
diff --git a/nest/rt-table.c b/nest/rt-table.c
index 390b3277..a10979e6 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -26,6 +26,66 @@
  * (see the route attribute module for a precise explanation) holding the
  * remaining route attributes which are expected to be shared by multiple
  * routes in order to conserve memory.
+ *
+ * There are several mechanisms that allow automatic update of routes in one
+ * routing table (dst) as a result of changes in another routing table (src).
+ * They handle issues of recursive next hop resolving, flowspec validation and
+ * RPKI validation.
+ *
+ * The first such mechanism is handling of recursive next hops. A route in the
+ * dst table has an indirect next hop address, which is resolved through a route
+ * in the src table (which may also be the same table) to get an immediate next
+ * hop. This is implemented using structure &hostcache attached to the src
+ * table, which contains &hostentry structures for each tracked next hop
+ * address. These structures are linked from recursive routes in dst tables,
+ * possibly multiple routes sharing one hostentry (as many routes may have the
+ * same indirect next hop). There is also a trie in the hostcache, which matches
+ * all prefixes that may influence resolving of tracked next hops.
+ *
+ * When a best route changes in the src table, the hostcache is notified using
+ * rt_notify_hostcache(), which immediately checks using the trie whether the
+ * change is relevant and if it is, then it schedules asynchronous hostcache
+ * recomputation. The recomputation is done by rt_update_hostcache() (called
+ * from rt_event() of src table), it walks through all hostentries and resolves
+ * them (by rt_update_hostentry()). It also updates the trie. If a change in
+ * hostentry resolution was found, then it schedules asynchronous nexthop
+ * recomputation of associated dst table. That is done by rt_next_hop_update()
+ * (called from rt_event() of dst table), it iterates over all routes in the dst
+ * table and re-examines their hostentries for changes. Note that in contrast to
+ * hostcache update, next hop update can be interrupted by main loop. These two
+ * full-table walks (over hostcache and dst table) are necessary due to absence
+ * of direct lookups (route -> affected nexthop, nexthop -> its route).
+ *
+ * The second mechanism is for flowspec validation, where validity of flowspec
+ * routes depends of resolving their network prefixes in IP routing tables. This
+ * is similar to the recursive next hop mechanism, but simpler as there are no
+ * intermediate hostcache and hostentries (because flows are less likely to
+ * share common net prefix than routes sharing a common next hop). In src table,
+ * there is a list of dst tables (list flowspec_links), this list is updated by
+ * flowpsec channels (by rt_flowspec_link() and rt_flowspec_unlink() during
+ * channel start/stop). Each dst table has its own trie of prefixes that may
+ * influence validation of flowspec routes in it (flowspec_trie).
+ *
+ * When a best route changes in the src table, rt_flowspec_notify() immediately
+ * checks all dst tables from the list using their tries to see whether the
+ * change is relevant for them. If it is, then an asynchronous re-validation of
+ * flowspec routes in the dst table is scheduled. That is also done by function
+ * rt_next_hop_update(), like nexthop recomputation above. It iterates over all
+ * flowspec routes and re-validates them. It also recalculates the trie.
+ *
+ * Note that in contrast to the hostcache update, here the trie is recalculated
+ * during the rt_next_hop_update(), which may be interleaved with IP route
+ * updates. The trie is flushed at the beginning of recalculation, which means
+ * that such updates may use partial trie to see if they are relevant. But it
+ * works anyway! Either affected flowspec was already re-validated and added to
+ * the trie, then IP route change would match the trie and trigger a next round
+ * of re-validation, or it was not yet re-validated and added to the trie, but
+ * will be re-validated later in this round anyway.
+ *
+ * The third mechanism is used for RPKI re-validation of IP routes and it is the
+ * simplest. It is just a list of subscribers in src table, who are notified
+ * when any change happened, but only after a settle time. Also, in RPKI case
+ * the dst is not a table, but a channel, who refeeds routes through a filter.
  */
 
 #undef LOCAL_DEBUG
@@ -44,6 +104,7 @@
 #include "lib/hash.h"
 #include "lib/string.h"
 #include "lib/alloca.h"
+#include "lib/flowspec.h"
 
 #ifdef CONFIG_BGP
 #include "proto/bgp/bgp.h"
@@ -62,41 +123,184 @@ static void rt_update_hostcache(rtable *tab);
 static void rt_next_hop_update(rtable *tab);
 static inline void rt_prune_table(rtable *tab);
 static inline void rt_schedule_notify(rtable *tab);
+static void rt_flowspec_notify(rtable *tab, net *net);
 
 
-/* Like fib_route(), but skips empty net entries */
-static inline void *
-net_route_ip4(rtable *t, net_addr_ip4 *n)
+static void
+net_init_with_trie(struct fib *f, void *N)
 {
-  net *r;
+  rtable *tab = SKIP_BACK(rtable, fib, f);
+  net *n = N;
 
-  while (r = net_find_valid(t, (net_addr *) n), (!r) && (n->pxlen > 0))
+  if (tab->trie)
+    trie_add_prefix(tab->trie, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);
+
+  if (tab->trie_new)
+    trie_add_prefix(tab->trie_new, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);
+}
+
+static inline net *
+net_route_ip4_trie(rtable *t, const net_addr_ip4 *n0)
+{
+  TRIE_WALK_TO_ROOT_IP4(t->trie, n0, n)
   {
-    n->pxlen--;
-    ip4_clrbit(&n->prefix, n->pxlen);
+    net *r;
+    if (r = net_find_valid(t, (net_addr *) &n))
+      return r;
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return NULL;
+}
+
+static inline net *
+net_route_vpn4_trie(rtable *t, const net_addr_vpn4 *n0)
+{
+  TRIE_WALK_TO_ROOT_IP4(t->trie, (const net_addr_ip4 *) n0, px)
+  {
+    net_addr_vpn4 n = NET_ADDR_VPN4(px.prefix, px.pxlen, n0->rd);
+
+    net *r;
+    if (r = net_find_valid(t, (net_addr *) &n))
+      return r;
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return NULL;
+}
+
+static inline net *
+net_route_ip6_trie(rtable *t, const net_addr_ip6 *n0)
+{
+  TRIE_WALK_TO_ROOT_IP6(t->trie, n0, n)
+  {
+    net *r;
+    if (r = net_find_valid(t, (net_addr *) &n))
+      return r;
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return NULL;
+}
+
+static inline net *
+net_route_vpn6_trie(rtable *t, const net_addr_vpn6 *n0)
+{
+  TRIE_WALK_TO_ROOT_IP6(t->trie, (const net_addr_ip6 *) n0, px)
+  {
+    net_addr_vpn6 n = NET_ADDR_VPN6(px.prefix, px.pxlen, n0->rd);
+
+    net *r;
+    if (r = net_find_valid(t, (net_addr *) &n))
+      return r;
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return NULL;
+}
+
+static inline void *
+net_route_ip6_sadr_trie(rtable *t, const net_addr_ip6_sadr *n0)
+{
+  TRIE_WALK_TO_ROOT_IP6(t->trie, (const net_addr_ip6 *) n0, px)
+  {
+    net_addr_ip6_sadr n = NET_ADDR_IP6_SADR(px.prefix, px.pxlen, n0->src_prefix, n0->src_pxlen);
+    net *best = NULL;
+    int best_pxlen = 0;
+
+    /* We need to do dst first matching. Since sadr addresses are hashed on dst
+       prefix only, find the hash table chain and go through it to find the
+       match with the longest matching src prefix. */
+    for (struct fib_node *fn = fib_get_chain(&t->fib, (net_addr *) &n); fn; fn = fn->next)
+    {
+      net_addr_ip6_sadr *a = (void *) fn->addr;
+
+      if (net_equal_dst_ip6_sadr(&n, a) &&
+	  net_in_net_src_ip6_sadr(&n, a) &&
+	  (a->src_pxlen >= best_pxlen))
+      {
+	best = fib_node_to_user(&t->fib, fn);
+	best_pxlen = a->src_pxlen;
+      }
+    }
+
+    if (best)
+      return best;
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return NULL;
+}
+
+static inline net *
+net_route_ip4_fib(rtable *t, const net_addr_ip4 *n0)
+{
+  net_addr_ip4 n;
+  net_copy_ip4(&n, n0);
+
+  net *r;
+  while (r = net_find_valid(t, (net_addr *) &n), (!r) && (n.pxlen > 0))
+  {
+    n.pxlen--;
+    ip4_clrbit(&n.prefix, n.pxlen);
+  }
+
+  return r;
+}
+
+static inline net *
+net_route_vpn4_fib(rtable *t, const net_addr_vpn4 *n0)
+{
+  net_addr_vpn4 n;
+  net_copy_vpn4(&n, n0);
+
+  net *r;
+  while (r = net_find_valid(t, (net_addr *) &n), (!r) && (n.pxlen > 0))
+  {
+    n.pxlen--;
+    ip4_clrbit(&n.prefix, n.pxlen);
+  }
+
+  return r;
+}
+
+static inline net *
+net_route_ip6_fib(rtable *t, const net_addr_ip6 *n0)
+{
+  net_addr_ip6 n;
+  net_copy_ip6(&n, n0);
+
+  net *r;
+  while (r = net_find_valid(t, (net_addr *) &n), (!r) && (n.pxlen > 0))
+  {
+    n.pxlen--;
+    ip6_clrbit(&n.prefix, n.pxlen);
+  }
+
+  return r;
+}
+
+static inline net *
+net_route_vpn6_fib(rtable *t, const net_addr_vpn6 *n0)
+{
+  net_addr_vpn6 n;
+  net_copy_vpn6(&n, n0);
+
+  net *r;
+  while (r = net_find_valid(t, (net_addr *) &n), (!r) && (n.pxlen > 0))
+  {
+    n.pxlen--;
+    ip6_clrbit(&n.prefix, n.pxlen);
   }
 
   return r;
 }
 
 static inline void *
-net_route_ip6(rtable *t, net_addr_ip6 *n)
+net_route_ip6_sadr_fib(rtable *t, const net_addr_ip6_sadr *n0)
 {
-  net *r;
-
-  while (r = net_find_valid(t, (net_addr *) n), (!r) && (n->pxlen > 0))
-  {
-    n->pxlen--;
-    ip6_clrbit(&n->prefix, n->pxlen);
-  }
-
-  return r;
-}
-
-static inline void *
-net_route_ip6_sadr(rtable *t, net_addr_ip6_sadr *n)
-{
-  struct fib_node *fn;
+  net_addr_ip6_sadr n;
+  net_copy_ip6_sadr(&n, n0);
 
   while (1)
   {
@@ -105,13 +309,13 @@ net_route_ip6_sadr(rtable *t, net_addr_ip6_sadr *n)
 
     /* We need to do dst first matching. Since sadr addresses are hashed on dst
        prefix only, find the hash table chain and go through it to find the
-       match with the smallest matching src prefix. */
-    for (fn = fib_get_chain(&t->fib, (net_addr *) n); fn; fn = fn->next)
+       match with the longest matching src prefix. */
+    for (struct fib_node *fn = fib_get_chain(&t->fib, (net_addr *) &n); fn; fn = fn->next)
     {
       net_addr_ip6_sadr *a = (void *) fn->addr;
 
-      if (net_equal_dst_ip6_sadr(n, a) &&
-	  net_in_net_src_ip6_sadr(n, a) &&
+      if (net_equal_dst_ip6_sadr(&n, a) &&
+	  net_in_net_src_ip6_sadr(&n, a) &&
 	  (a->src_pxlen >= best_pxlen))
       {
 	best = fib_node_to_user(&t->fib, fn);
@@ -122,38 +326,52 @@ net_route_ip6_sadr(rtable *t, net_addr_ip6_sadr *n)
     if (best)
       return best;
 
-    if (!n->dst_pxlen)
+    if (!n.dst_pxlen)
       break;
 
-    n->dst_pxlen--;
-    ip6_clrbit(&n->dst_prefix, n->dst_pxlen);
+    n.dst_pxlen--;
+    ip6_clrbit(&n.dst_prefix, n.dst_pxlen);
   }
 
   return NULL;
 }
 
-void *
+net *
 net_route(rtable *tab, const net_addr *n)
 {
   ASSERT(tab->addr_type == n->type);
 
-  net_addr *n0 = alloca(n->length);
-  net_copy(n0, n);
-
   switch (n->type)
   {
   case NET_IP4:
+    if (tab->trie)
+      return net_route_ip4_trie(tab, (net_addr_ip4 *) n);
+    else
+      return net_route_ip4_fib (tab, (net_addr_ip4 *) n);
+
   case NET_VPN4:
-  case NET_ROA4:
-    return net_route_ip4(tab, (net_addr_ip4 *) n0);
+    if (tab->trie)
+      return net_route_vpn4_trie(tab, (net_addr_vpn4 *) n);
+    else
+      return net_route_vpn4_fib (tab, (net_addr_vpn4 *) n);
 
   case NET_IP6:
+    if (tab->trie)
+      return net_route_ip6_trie(tab, (net_addr_ip6 *) n);
+    else
+      return net_route_ip6_fib (tab, (net_addr_ip6 *) n);
+
   case NET_VPN6:
-  case NET_ROA6:
-    return net_route_ip6(tab, (net_addr_ip6 *) n0);
+    if (tab->trie)
+      return net_route_vpn6_trie(tab, (net_addr_vpn6 *) n);
+    else
+      return net_route_vpn6_fib (tab, (net_addr_vpn6 *) n);
 
   case NET_IP6_SADR:
-    return net_route_ip6_sadr(tab, (net_addr_ip6_sadr *) n0);
+    if (tab->trie)
+      return net_route_ip6_sadr_trie(tab, (net_addr_ip6_sadr *) n);
+    else
+      return net_route_ip6_sadr_fib (tab, (net_addr_ip6_sadr *) n);
 
   default:
     return NULL;
@@ -162,7 +380,35 @@ net_route(rtable *tab, const net_addr *n)
 
 
 static int
-net_roa_check_ip4(rtable *tab, const net_addr_ip4 *px, u32 asn)
+net_roa_check_ip4_trie(rtable *tab, const net_addr_ip4 *px, u32 asn)
+{
+  int anything = 0;
+
+  TRIE_WALK_TO_ROOT_IP4(tab->trie, px, px0)
+  {
+    net_addr_roa4 roa0 = NET_ADDR_ROA4(px0.prefix, px0.pxlen, 0, 0);
+
+    struct fib_node *fn;
+    for (fn = fib_get_chain(&tab->fib, (net_addr *) &roa0); fn; fn = fn->next)
+    {
+      net_addr_roa4 *roa = (void *) fn->addr;
+      net *r = fib_node_to_user(&tab->fib, fn);
+
+      if (net_equal_prefix_roa4(roa, &roa0) && rte_is_valid(r->routes))
+      {
+	anything = 1;
+	if (asn && (roa->asn == asn) && (roa->max_pxlen >= px->pxlen))
+	  return ROA_VALID;
+      }
+    }
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return anything ? ROA_INVALID : ROA_UNKNOWN;
+}
+
+static int
+net_roa_check_ip4_fib(rtable *tab, const net_addr_ip4 *px, u32 asn)
 {
   struct net_addr_roa4 n = NET_ADDR_ROA4(px->prefix, px->pxlen, 0, 0);
   struct fib_node *fn;
@@ -194,7 +440,35 @@ net_roa_check_ip4(rtable *tab, const net_addr_ip4 *px, u32 asn)
 }
 
 static int
-net_roa_check_ip6(rtable *tab, const net_addr_ip6 *px, u32 asn)
+net_roa_check_ip6_trie(rtable *tab, const net_addr_ip6 *px, u32 asn)
+{
+  int anything = 0;
+
+  TRIE_WALK_TO_ROOT_IP6(tab->trie, px, px0)
+  {
+    net_addr_roa6 roa0 = NET_ADDR_ROA6(px0.prefix, px0.pxlen, 0, 0);
+
+    struct fib_node *fn;
+    for (fn = fib_get_chain(&tab->fib, (net_addr *) &roa0); fn; fn = fn->next)
+    {
+      net_addr_roa6 *roa = (void *) fn->addr;
+      net *r = fib_node_to_user(&tab->fib, fn);
+
+      if (net_equal_prefix_roa6(roa, &roa0) && rte_is_valid(r->routes))
+      {
+	anything = 1;
+	if (asn && (roa->asn == asn) && (roa->max_pxlen >= px->pxlen))
+	  return ROA_VALID;
+      }
+    }
+  }
+  TRIE_WALK_TO_ROOT_END;
+
+  return anything ? ROA_INVALID : ROA_UNKNOWN;
+}
+
+static int
+net_roa_check_ip6_fib(rtable *tab, const net_addr_ip6 *px, u32 asn)
 {
   struct net_addr_roa6 n = NET_ADDR_ROA6(px->prefix, px->pxlen, 0, 0);
   struct fib_node *fn;
@@ -244,9 +518,19 @@ int
 net_roa_check(rtable *tab, const net_addr *n, u32 asn)
 {
   if ((tab->addr_type == NET_ROA4) && (n->type == NET_IP4))
-    return net_roa_check_ip4(tab, (const net_addr_ip4 *) n, asn);
+  {
+    if (tab->trie)
+      return net_roa_check_ip4_trie(tab, (const net_addr_ip4 *) n, asn);
+    else
+      return net_roa_check_ip4_fib (tab, (const net_addr_ip4 *) n, asn);
+  }
   else if ((tab->addr_type == NET_ROA6) && (n->type == NET_IP6))
-    return net_roa_check_ip6(tab, (const net_addr_ip6 *) n, asn);
+  {
+    if (tab->trie)
+      return net_roa_check_ip6_trie(tab, (const net_addr_ip6 *) n, asn);
+    else
+      return net_roa_check_ip6_fib (tab, (const net_addr_ip6 *) n, asn);
+  }
   else
     return ROA_UNKNOWN;	/* Should not happen */
 }
@@ -974,6 +1258,9 @@ rte_announce(rtable *tab, uint type, net *net, rte *new, rte *old,
 
     if (tab->hostcache)
       rt_notify_hostcache(tab, net);
+
+    if (!EMPTY_LIST(tab->flowspec_links))
+      rt_flowspec_notify(tab, net);
   }
 
   rt_schedule_notify(tab);
@@ -1035,6 +1322,10 @@ rte_validate(rte *e)
 
   if (net_type_match(n->n.addr, NB_DEST) == !e->attrs->dest)
   {
+    /* Exception for flowspec that failed validation */
+    if (net_is_flow(n->n.addr) && (e->attrs->dest == RTD_UNREACHABLE))
+      return 1;
+
     log(L_WARN "Ignoring route %N with invalid dest %d received via %s",
 	n->n.addr, e->attrs->dest, e->sender->proto->name);
     return 0;
@@ -1878,6 +2169,90 @@ rt_unsubscribe(struct rt_subscription *s)
   rt_unlock_table(s->tab);
 }
 
+static struct rt_flowspec_link *
+rt_flowspec_find_link(rtable *src, rtable *dst)
+{
+  struct rt_flowspec_link *ln;
+  WALK_LIST(ln, src->flowspec_links)
+    if ((ln->src == src) && (ln->dst == dst))
+      return ln;
+
+  return NULL;
+}
+
+void
+rt_flowspec_link(rtable *src, rtable *dst)
+{
+  ASSERT(rt_is_ip(src));
+  ASSERT(rt_is_flow(dst));
+
+  struct rt_flowspec_link *ln = rt_flowspec_find_link(src, dst);
+
+  if (!ln)
+  {
+    rt_lock_table(src);
+    rt_lock_table(dst);
+
+    ln = mb_allocz(src->rp, sizeof(struct rt_flowspec_link));
+    ln->src = src;
+    ln->dst = dst;
+    add_tail(&src->flowspec_links, &ln->n);
+  }
+
+  ln->uc++;
+}
+
+void
+rt_flowspec_unlink(rtable *src, rtable *dst)
+{
+  struct rt_flowspec_link *ln = rt_flowspec_find_link(src, dst);
+
+  ASSERT(ln && (ln->uc > 0));
+
+  ln->uc--;
+
+  if (!ln->uc)
+  {
+    rem_node(&ln->n);
+    mb_free(ln);
+
+    rt_unlock_table(src);
+    rt_unlock_table(dst);
+  }
+}
+
+static void
+rt_flowspec_notify(rtable *src, net *net)
+{
+  /* Only IP tables are src links */
+  ASSERT(rt_is_ip(src));
+
+  struct rt_flowspec_link *ln;
+  WALK_LIST(ln, src->flowspec_links)
+  {
+    rtable *dst = ln->dst;
+    ASSERT(rt_is_flow(dst));
+
+    /* No need to inspect it further if recalculation is already active */
+    if ((dst->nhu_state == NHU_SCHEDULED) || (dst->nhu_state == NHU_DIRTY))
+      continue;
+
+    if (trie_match_net(dst->flowspec_trie, net->n.addr))
+      rt_schedule_nhu(dst);
+  }
+}
+
+static void
+rt_flowspec_reset_trie(rtable *tab)
+{
+  linpool *lp = tab->flowspec_trie->lp;
+  int ipv4 = tab->flowspec_trie->ipv4;
+
+  lp_flush(lp);
+  tab->flowspec_trie = f_new_trie(lp, 0);
+  tab->flowspec_trie->ipv4 = ipv4;
+}
+
 static void
 rt_free(resource *_r)
 {
@@ -1940,16 +2315,31 @@ rt_setup(pool *pp, struct rtable_config *cf)
 
   fib_init(&t->fib, p, t->addr_type, sizeof(net), OFFSETOF(net, n), 0, NULL);
 
+  if (cf->trie_used)
+  {
+    t->trie = f_new_trie(lp_new_default(p), 0);
+    t->trie->ipv4 = net_val_match(t->addr_type, NB_IP4 | NB_VPN4 | NB_ROA4);
+
+    t->fib.init = net_init_with_trie;
+  }
+
+  init_list(&t->channels);
+  init_list(&t->flowspec_links);
+  init_list(&t->subscribers);
+
   if (!(t->internal = cf->internal))
   {
-    init_list(&t->channels);
     hmap_init(&t->id_map, p, 1024);
     hmap_set(&t->id_map, 0);
 
-    init_list(&t->subscribers);
-
     t->rt_event = ev_new_init(p, rt_event, t);
     t->last_rt_change = t->gc_time = current_time();
+
+    if (rt_is_flow(t))
+    {
+      t->flowspec_trie = f_new_trie(lp_new_default(p), 0);
+      t->flowspec_trie->ipv4 = (t->addr_type == NET_FLOW4);
+    }
   }
 
   return t;
@@ -2012,6 +2402,13 @@ rt_prune_table(rtable *tab)
 
     FIB_ITERATE_INIT(fit, &tab->fib);
     tab->prune_state = 2;
+
+    if (tab->prune_trie)
+    {
+      /* Init prefix trie pruning */
+      tab->trie_new = f_new_trie(lp_new_default(tab->rp), 0);
+      tab->trie_new->ipv4 = tab->trie->ipv4;
+    }
   }
 
 again:
@@ -2020,17 +2417,17 @@ again:
       rte *e;
 
     rescan:
+      if (limit <= 0)
+      {
+	FIB_ITERATE_PUT(fit);
+	ev_schedule(tab->rt_event);
+	return;
+      }
+
       for (e=n->routes; e; e=e->next)
       {
 	if (e->sender->flush_active || (e->flags & REF_DISCARD))
 	  {
-	    if (limit <= 0)
-	      {
-		FIB_ITERATE_PUT(fit);
-		ev_schedule(tab->rt_event);
-		return;
-	      }
-
 	    rte_discard(e);
 	    limit--;
 
@@ -2039,13 +2436,6 @@ again:
 
 	if (e->flags & REF_MODIFY)
 	  {
-	    if (limit <= 0)
-	      {
-		FIB_ITERATE_PUT(fit);
-		ev_schedule(tab->rt_event);
-		return;
-	      }
-
 	    rte_modify(e);
 	    limit--;
 
@@ -2059,6 +2449,12 @@ again:
 	  fib_delete(&tab->fib, n);
 	  goto again;
 	}
+
+      if (tab->trie_new)
+      {
+	trie_add_prefix(tab->trie_new, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);
+	limit--;
+      }
     }
   FIB_ITERATE_END;
 
@@ -2072,6 +2468,37 @@ again:
   /* state change 2->0, 3->1 */
   tab->prune_state &= 1;
 
+  if (tab->trie_new)
+  {
+    /* Finish prefix trie pruning */
+
+    if (!tab->trie_lock_count)
+    {
+      rfree(tab->trie->lp);
+    }
+    else
+    {
+      ASSERT(!tab->trie_old);
+      tab->trie_old = tab->trie;
+      tab->trie_old_lock_count = tab->trie_lock_count;
+      tab->trie_lock_count = 0;
+    }
+
+    tab->trie = tab->trie_new;
+    tab->trie_new = NULL;
+    tab->prune_trie = 0;
+  }
+  else
+  {
+    /* Schedule prefix trie pruning */
+    if (tab->trie && !tab->trie_old && (tab->trie->prefix_count > (2 * tab->fib.entries)))
+    {
+      /* state change 0->1, 2->3 */
+      tab->prune_state |= 1;
+      tab->prune_trie = 1;
+    }
+  }
+
   if (tab->prune_state > 0)
     ev_schedule(tab->rt_event);
 
@@ -2089,6 +2516,72 @@ again:
   return;
 }
 
+/**
+ * rt_lock_trie - lock a prefix trie of a routing table
+ * @tab: routing table with prefix trie to be locked
+ *
+ * The prune loop may rebuild the prefix trie and invalidate f_trie_walk_state
+ * structures. Therefore, asynchronous walks should lock the prefix trie using
+ * this function. That allows the prune loop to rebuild the trie, but postpones
+ * its freeing until all walks are done (unlocked by rt_unlock_trie()).
+ *
+ * Return a current trie that will be locked, the value should be passed back to
+ * rt_unlock_trie() for unlocking.
+ *
+ */
+struct f_trie *
+rt_lock_trie(rtable *tab)
+{
+  ASSERT(tab->trie);
+
+  tab->trie_lock_count++;
+  return tab->trie;
+}
+
+/**
+ * rt_unlock_trie - unlock a prefix trie of a routing table
+ * @tab: routing table with prefix trie to be locked
+ * @trie: value returned by matching rt_lock_trie()
+ *
+ * Done for trie locked by rt_lock_trie() after walk over the trie is done.
+ * It may free the trie and schedule next trie pruning.
+ */
+void
+rt_unlock_trie(rtable *tab, struct f_trie *trie)
+{
+  ASSERT(trie);
+
+  if (trie == tab->trie)
+  {
+    /* Unlock the current prefix trie */
+    ASSERT(tab->trie_lock_count);
+    tab->trie_lock_count--;
+  }
+  else if (trie == tab->trie_old)
+  {
+    /* Unlock the old prefix trie */
+    ASSERT(tab->trie_old_lock_count);
+    tab->trie_old_lock_count--;
+
+    /* Free old prefix trie that is no longer needed */
+    if (!tab->trie_old_lock_count)
+    {
+      rfree(tab->trie_old->lp);
+      tab->trie_old = NULL;
+
+      /* Kick prefix trie pruning that was postponed */
+      if (tab->trie && (tab->trie->prefix_count > (2 * tab->fib.entries)))
+      {
+	tab->prune_trie = 1;
+	rt_schedule_prune(tab);
+      }
+    }
+  }
+  else
+    log(L_BUG "Invalid arg to rt_unlock_trie()");
+}
+
+
 void
 rt_preconfig(struct config *c)
 {
@@ -2104,21 +2597,6 @@ rt_preconfig(struct config *c)
  * triggered by rt_schedule_nhu().
  */
 
-static inline int
-rta_next_hop_outdated(rta *a)
-{
-  struct hostentry *he = a->hostentry;
-
-  if (!he)
-    return 0;
-
-  if (!he->src)
-    return a->dest != RTD_UNREACHABLE;
-
-  return (a->dest != he->dest) || (a->igp_metric != he->igp_metric) ||
-    (!he->nexthop_linkable) || !nexthop_same(&(a->nh), &(he->src->nh));
-}
-
 void
 rta_apply_hostentry(rta *a, struct hostentry *he, mpls_label_stack *mls)
 {
@@ -2210,9 +2688,27 @@ no_nexthop:
     }
 }
 
+static inline int
+rta_next_hop_outdated(rta *a)
+{
+  struct hostentry *he = a->hostentry;
+
+  if (!he)
+    return 0;
+
+  if (!he->src)
+    return a->dest != RTD_UNREACHABLE;
+
+  return (a->dest != he->dest) || (a->igp_metric != he->igp_metric) ||
+    (!he->nexthop_linkable) || !nexthop_same(&(a->nh), &(he->src->nh));
+}
+
 static inline rte *
 rt_next_hop_update_rte(rtable *tab UNUSED, rte *old)
 {
+  if (!rta_next_hop_outdated(old->attrs))
+    return NULL;
+
   rta *a = alloca(RTA_MAX_SIZE);
   memcpy(a, old->attrs, rta_size(old->attrs));
 
@@ -2229,6 +2725,152 @@ rt_next_hop_update_rte(rtable *tab UNUSED, rte *old)
   return e;
 }
 
+
+#ifdef CONFIG_BGP
+
+static inline int
+net_flow_has_dst_prefix(const net_addr *n)
+{
+  ASSUME(net_is_flow(n));
+
+  if (n->pxlen)
+    return 1;
+
+  if (n->type == NET_FLOW4)
+  {
+    const net_addr_flow4 *n4 = (void *) n;
+    return (n4->length > sizeof(net_addr_flow4)) && (n4->data[0] == FLOW_TYPE_DST_PREFIX);
+  }
+  else
+  {
+    const net_addr_flow6 *n6 = (void *) n;
+    return (n6->length > sizeof(net_addr_flow6)) && (n6->data[0] == FLOW_TYPE_DST_PREFIX);
+  }
+}
+
+static inline int
+rta_as_path_is_empty(rta *a)
+{
+  eattr *e = ea_find(a->eattrs, EA_CODE(PROTOCOL_BGP, BA_AS_PATH));
+  return !e || (as_path_getlen(e->u.ptr) == 0);
+}
+
+static inline u32
+rta_get_first_asn(rta *a)
+{
+  eattr *e = ea_find(a->eattrs, EA_CODE(PROTOCOL_BGP, BA_AS_PATH));
+  u32 asn;
+
+  return (e && as_path_get_first_regular(e->u.ptr, &asn)) ? asn : 0;
+}
+
+int
+rt_flowspec_check(rtable *tab_ip, rtable *tab_flow, const net_addr *n, rta *a, int interior)
+{
+  ASSERT(rt_is_ip(tab_ip));
+  ASSERT(rt_is_flow(tab_flow));
+  ASSERT(tab_ip->trie);
+
+  /* RFC 8955 6. a) Flowspec has defined dst prefix */
+  if (!net_flow_has_dst_prefix(n))
+    return 0;
+
+  /* RFC 9117 4.1. Accept  AS_PATH is empty (fr */
+  if (interior && rta_as_path_is_empty(a))
+    return 1;
+
+
+  /* RFC 8955 6. b) Flowspec and its best-match route have the same originator */
+
+  /* Find flowspec dst prefix */
+  net_addr dst;
+  if (n->type == NET_FLOW4)
+    net_fill_ip4(&dst, net4_prefix(n), net4_pxlen(n));
+  else
+    net_fill_ip6(&dst, net6_prefix(n), net6_pxlen(n));
+
+  /* Find best-match BGP unicast route for flowspec dst prefix */
+  net *nb = net_route(tab_ip, &dst);
+  rte *rb = nb ? nb->routes : NULL;
+
+  /* Register prefix to trie for tracking further changes */
+  int max_pxlen = (n->type == NET_FLOW4) ? IP4_MAX_PREFIX_LENGTH : IP6_MAX_PREFIX_LENGTH;
+  trie_add_prefix(tab_flow->flowspec_trie, &dst, (nb ? nb->n.addr->pxlen : 0), max_pxlen);
+
+  /* No best-match BGP route -> no flowspec */
+  if (!rb || (rb->attrs->source != RTS_BGP))
+    return 0;
+
+  /* Find ORIGINATOR_ID values */
+  u32 orig_a = ea_get_int(a->eattrs, EA_CODE(PROTOCOL_BGP, BA_ORIGINATOR_ID), 0);
+  u32 orig_b = ea_get_int(rb->attrs->eattrs, EA_CODE(PROTOCOL_BGP, BA_ORIGINATOR_ID), 0);
+
+  /* Originator is either ORIGINATOR_ID (if present), or BGP neighbor address (if not) */
+  if ((orig_a != orig_b) || (!orig_a && !orig_b && !ipa_equal(a->from, rb->attrs->from)))
+    return 0;
+
+
+  /* Find ASN of the best-match route, for use in next checks */
+  u32 asn_b = rta_get_first_asn(rb->attrs);
+  if (!asn_b)
+    return 0;
+
+  /* RFC 9117 4.2. For EBGP, flowspec and its best-match route are from the same AS */
+  if (!interior && (rta_get_first_asn(a) != asn_b))
+    return 0;
+
+  /* RFC 8955 6. c) More-specific routes are from the same AS as the best-match route */
+  TRIE_WALK(tab_ip->trie, subnet, &dst)
+  {
+    net *nc = net_find_valid(tab_ip, &subnet);
+    if (!nc)
+      continue;
+
+    rte *rc = nc->routes;
+    if (rc->attrs->source != RTS_BGP)
+      return 0;
+
+    if (rta_get_first_asn(rc->attrs) != asn_b)
+      return 0;
+  }
+  TRIE_WALK_END;
+
+  return 1;
+}
+
+#endif /* CONFIG_BGP */
+
+static rte *
+rt_flowspec_update_rte(rtable *tab, rte *r)
+{
+#ifdef CONFIG_BGP
+  if ((r->attrs->source != RTS_BGP) || !r->u.bgp.base_table)
+    return NULL;
+
+  const net_addr *n = r->net->n.addr;
+  struct bgp_proto *p = (void *) r->attrs->src->proto;
+  int valid = rt_flowspec_check(r->u.bgp.base_table, tab, n, r->attrs, p->is_interior);
+  int dest = valid ? RTD_NONE : RTD_UNREACHABLE;
+
+  if (dest == r->attrs->dest)
+    return NULL;
+
+  rta *a = alloca(RTA_MAX_SIZE);
+  memcpy(a, r->attrs, rta_size(r->attrs));
+  a->dest = dest;
+  a->aflags = 0;
+
+  rte *new = sl_alloc(rte_slab);
+  memcpy(new, r, sizeof(rte));
+  new->attrs = rta_lookup(a);
+
+  return new;
+#else
+  return NULL;
+#endif
+}
+
+
 static inline int
 rt_next_hop_update_net(rtable *tab, net *n)
 {
@@ -2241,9 +2883,14 @@ rt_next_hop_update_net(rtable *tab, net *n)
     return 0;
 
   for (k = &n->routes; e = *k; k = &e->next)
-    if (rta_next_hop_outdated(e->attrs))
+  {
+    if (!net_is_flow(n->n.addr))
+      new = rt_next_hop_update_rte(tab, e);
+    else
+      new = rt_flowspec_update_rte(tab, e);
+
+    if (new)
       {
-	new = rt_next_hop_update_rte(tab, e);
 	*k = new;
 
 	rte_trace_in(D_ROUTES, new->sender, new, "updated");
@@ -2262,6 +2909,7 @@ rt_next_hop_update_net(rtable *tab, net *n)
 	e = new;
 	count++;
       }
+  }
 
   if (!count)
     return 0;
@@ -2309,6 +2957,9 @@ rt_next_hop_update(rtable *tab)
     {
       FIB_ITERATE_INIT(fit, &tab->fib);
       tab->nhu_state = NHU_RUNNING;
+
+      if (tab->flowspec_trie)
+	rt_flowspec_reset_trie(tab);
     }
 
   FIB_ITERATE_START(&tab->fib, fit, net, n)
@@ -2397,6 +3048,22 @@ rt_unlock_table(rtable *r)
     }
 }
 
+static int
+rt_reconfigure(rtable *tab, struct rtable_config *new, struct rtable_config *old)
+{
+  if ((new->addr_type != old->addr_type) ||
+      (new->sorted != old->sorted) ||
+      (new->trie_used != old->trie_used))
+    return 0;
+
+  DBG("\t%s: same\n", new->name);
+  new->table = tab;
+  tab->name = new->name;
+  tab->config = new;
+
+  return 1;
+}
+
 static struct rtable_config *
 rt_find_table_config(struct config *cf, char *name)
 {
@@ -2426,28 +3093,19 @@ rt_commit(struct config *new, struct config *old)
     {
       WALK_LIST(o, old->tables)
 	{
-	  rtable *ot = o->table;
-	  if (!ot->deleted)
-	    {
-	      r = rt_find_table_config(new, o->name);
-	      if (r && (r->addr_type == o->addr_type) && !new->shutdown)
-		{
-		  DBG("\t%s: same\n", o->name);
-		  r->table = ot;
-		  ot->name = r->name;
-		  ot->config = r;
-		  if (o->sorted != r->sorted)
-		    log(L_WARN "Reconfiguration of rtable sorted flag not implemented");
-		}
-	      else
-		{
-		  DBG("\t%s: deleted\n", o->name);
-		  ot->deleted = old;
-		  config_add_obstacle(old);
-		  rt_lock_table(ot);
-		  rt_unlock_table(ot);
-		}
-	    }
+	  rtable *tab = o->table;
+	  if (tab->deleted)
+	    continue;
+
+	  r = rt_find_table_config(new, o->name);
+	  if (r && !new->shutdown && rt_reconfigure(tab, r, o))
+	    continue;
+
+	  DBG("\t%s: deleted\n", o->name);
+	  tab->deleted = old;
+	  config_add_obstacle(old);
+	  rt_lock_table(tab);
+	  rt_unlock_table(tab);
 	}
     }
 
diff --git a/proto/babel/babel.c b/proto/babel/babel.c
index 1e87212c..e43818f5 100644
--- a/proto/babel/babel.c
+++ b/proto/babel/babel.c
@@ -63,7 +63,7 @@ static inline void babel_iface_kick_timer(struct babel_iface *ifa);
  */
 
 static void
-babel_init_entry(void *E)
+babel_init_entry(struct fib *f UNUSED, void *E)
 {
   struct babel_entry *e = E;
 
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index 15713b63..1f927cbd 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -1683,6 +1683,10 @@ bgp_preexport(struct proto *P, rte **new, struct linpool *pool UNUSED)
   if (src == NULL)
     return 0;
 
+  /* Reject flowspec that failed validation */
+  if ((e->attrs->dest == RTD_UNREACHABLE) && net_is_flow(e->net->n.addr))
+      return -1;
+
   /* IBGP route reflection, RFC 4456 */
   if (p->is_internal && src->is_internal && (p->local_as == src->local_as))
   {
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index b6f21bc6..619a816b 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -101,6 +101,7 @@
  * RFC 8203 - BGP Administrative Shutdown Communication
  * RFC 8212 - Default EBGP Route Propagation Behavior without Policies
  * RFC 8654 - Extended Message Support for BGP
+ * RFC 9117 - Revised Validation Procedure for BGP Flow Specifications
  * draft-ietf-idr-ext-opt-param-07
  * draft-uttaro-idr-bgp-persistence-04
  * draft-walton-bgp-hostname-capability-02
@@ -1740,6 +1741,9 @@ bgp_channel_init(struct channel *C, struct channel_config *CF)
 
   if (cf->igp_table_ip6)
     c->igp_table_ip6 = cf->igp_table_ip6->table;
+
+  if (cf->base_table)
+    c->base_table = cf->base_table->table;
 }
 
 static int
@@ -1755,6 +1759,12 @@ bgp_channel_start(struct channel *C)
   if (c->igp_table_ip6)
     rt_lock_table(c->igp_table_ip6);
 
+  if (c->base_table)
+  {
+    rt_lock_table(c->base_table);
+    rt_flowspec_link(c->base_table, c->c.table);
+  }
+
   c->pool = p->p.pool; // XXXX
   bgp_init_bucket_table(c);
   bgp_init_prefix_table(c);
@@ -1839,6 +1849,12 @@ bgp_channel_cleanup(struct channel *C)
   if (c->igp_table_ip6)
     rt_unlock_table(c->igp_table_ip6);
 
+  if (c->base_table)
+  {
+    rt_flowspec_unlink(c->base_table, c->c.table);
+    rt_unlock_table(c->base_table);
+  }
+
   c->index = 0;
 
   /* Cleanup rest of bgp_channel starting at pool field */
@@ -1886,6 +1902,25 @@ bgp_default_igp_table(struct bgp_config *cf, struct bgp_channel_config *cc, u32
   cf_error("Undefined IGP table");
 }
 
+static struct rtable_config *
+bgp_default_base_table(struct bgp_config *cf, struct bgp_channel_config *cc)
+{
+  /* Expected table type */
+  u32 type = (cc->afi == BGP_AF_FLOW4) ? NET_IP4 : NET_IP6;
+
+  /* First, try appropriate IP channel */
+  u32 afi2 = BGP_AF(BGP_AFI(cc->afi), BGP_SAFI_UNICAST);
+  struct bgp_channel_config *cc2 = bgp_find_channel_config(cf, afi2);
+  if (cc2 && (cc2->c.table->addr_type == type))
+    return cc2->c.table;
+
+  /* Last, try default table of given type */
+  struct rtable_config *tab = cf->c.global->def_tables[type];
+  if (tab)
+    return tab;
+
+  cf_error("Undefined base table");
+}
 
 void
 bgp_postconfig(struct proto_config *CF)
@@ -2030,6 +2065,14 @@ bgp_postconfig(struct proto_config *CF)
 	cf_error("Mismatched IGP table type");
     }
 
+    /* Default value of base table */
+    if ((BGP_SAFI(cc->afi) == BGP_SAFI_FLOW) && cc->validate && !cc->base_table)
+      cc->base_table = bgp_default_base_table(cf, cc);
+
+    if (cc->base_table && !cc->base_table->trie_used)
+      cf_error("Flowspec validation requires base table (%s) with trie",
+	       cc->base_table->name);
+
     if (cf->multihop && (cc->gw_mode == GW_DIRECT))
       cf_error("Multihop BGP cannot use direct gateway mode");
 
@@ -2098,7 +2141,7 @@ bgp_reconfigure(struct proto *P, struct proto_config *CF)
   return same;
 }
 
-#define IGP_TABLE(cf, sym) ((cf)->igp_table_##sym ? (cf)->igp_table_##sym ->table : NULL )
+#define TABLE(cf, NAME) ((cf)->NAME ? (cf)->NAME->table : NULL )
 
 static int
 bgp_channel_reconfigure(struct channel *C, struct channel_config *CC, int *import_changed, int *export_changed)
@@ -2109,6 +2152,7 @@ bgp_channel_reconfigure(struct channel *C, struct channel_config *CC, int *impor
   struct bgp_channel_config *old = c->cf;
 
   if ((new->secondary != old->secondary) ||
+      (new->validate != old->validate) ||
       (new->gr_able != old->gr_able) ||
       (new->llgr_able != old->llgr_able) ||
       (new->llgr_time != old->llgr_time) ||
@@ -2116,8 +2160,9 @@ bgp_channel_reconfigure(struct channel *C, struct channel_config *CC, int *impor
       (new->add_path != old->add_path) ||
       (new->import_table != old->import_table) ||
       (new->export_table != old->export_table) ||
-      (IGP_TABLE(new, ip4) != IGP_TABLE(old, ip4)) ||
-      (IGP_TABLE(new, ip6) != IGP_TABLE(old, ip6)))
+      (TABLE(new, igp_table_ip4) != TABLE(old, igp_table_ip4)) ||
+      (TABLE(new, igp_table_ip6) != TABLE(old, igp_table_ip6)) ||
+      (TABLE(new, base_table) != TABLE(old, base_table)))
     return 0;
 
   if (new->mandatory && !old->mandatory && (C->channel_state != CS_UP))
@@ -2531,6 +2576,9 @@ bgp_show_proto_info(struct proto *P)
 
       if (c->igp_table_ip6)
 	cli_msg(-1006, "    IGP IPv6 table: %s", c->igp_table_ip6->name);
+
+      if (c->base_table)
+	cli_msg(-1006, "    Base table:     %s", c->base_table->name);
     }
   }
 }
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 08e751e7..4969c0b9 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -147,6 +147,7 @@ struct bgp_channel_config {
   u8 mandatory;				/* Channel is mandatory in capability negotiation */
   u8 gw_mode;				/* How we compute route gateway from next_hop attr, see GW_* */
   u8 secondary;				/* Accept also non-best routes (i.e. RA_ACCEPTED) */
+  u8 validate;				/* Validate Flowspec per RFC 8955 (6) */
   u8 gr_able;				/* Allow full graceful restart for the channel */
   u8 llgr_able;				/* Allow full long-lived GR for the channel */
   uint llgr_time;			/* Long-lived graceful restart stale time */
@@ -160,6 +161,7 @@ struct bgp_channel_config {
 
   struct rtable_config *igp_table_ip4;	/* Table for recursive IPv4 next hop lookups */
   struct rtable_config *igp_table_ip6;	/* Table for recursive IPv6 next hop lookups */
+  struct rtable_config *base_table;	/* Base table for Flowspec validation */
 };
 
 #define BGP_PT_INTERNAL		1
@@ -341,6 +343,7 @@ struct bgp_channel {
 
   rtable *igp_table_ip4;		/* Table for recursive IPv4 next hop lookups */
   rtable *igp_table_ip6;		/* Table for recursive IPv6 next hop lookups */
+  rtable *base_table;			/* Base table for Flowspec validation */
 
   /* Rest are zeroed when down */
   pool *pool;
@@ -451,6 +454,7 @@ struct bgp_parse_state {
   jmp_buf err_jmpbuf;
 
   struct hostentry *hostentry;
+  struct rtable *base_table;
   adata *mpls_labels;
 
   /* Cached state for bgp_rte_update() */
@@ -517,7 +521,7 @@ struct rte_source *bgp_get_source(struct bgp_proto *p, u32 path_id);
 static inline int
 rte_resolvable(rte *rt)
 {
-  return rt->attrs->dest == RTD_UNICAST;
+  return rt->attrs->dest != RTD_UNREACHABLE;
 }
 
 
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 7cbc9985..241aa7c2 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -31,7 +31,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	STRICT, BIND, CONFEDERATION, MEMBER, MULTICAST, FLOW4, FLOW6, LONG,
 	LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL, SETS,
 	DYNAMIC, RANGE, NAME, DIGITS, BGP_AIGP, AIGP, ORIGINATE, COST, ENFORCE,
-	FIRST, FREE)
+	FIRST, FREE, VALIDATE, BASE)
 
 %type <i> bgp_nh
 %type <i32> bgp_afi
@@ -256,6 +256,11 @@ bgp_channel_item:
  | GATEWAY DIRECT { BGP_CC->gw_mode = GW_DIRECT; }
  | GATEWAY RECURSIVE { BGP_CC->gw_mode = GW_RECURSIVE; }
  | SECONDARY bool { BGP_CC->secondary = $2; }
+ | VALIDATE bool {
+    BGP_CC->validate = $2;
+    if (BGP_SAFI(BGP_CC->afi) != BGP_SAFI_FLOW)
+      cf_error("Validate option limited to flowspec channels");
+   }
  | GRACEFUL RESTART bool { BGP_CC->gr_able = $3; }
  | LONG LIVED GRACEFUL RESTART bool { BGP_CC->llgr_able = $5; }
  | LONG LIVED STALE TIME expr { BGP_CC->llgr_time = $5; }
@@ -279,6 +284,16 @@ bgp_channel_item:
     else
       cf_error("Mismatched IGP table type");
    }
+ | BASE TABLE rtable {
+    if (BGP_SAFI(BGP_CC->afi) != BGP_SAFI_FLOW)
+      cf_error("Base table option limited to flowspec channels");
+
+    if (((BGP_CC->afi == BGP_AF_FLOW4) && ($3->addr_type == NET_IP4)) ||
+        ((BGP_CC->afi == BGP_AF_FLOW6) && ($3->addr_type == NET_IP6)))
+      BGP_CC->base_table = $3;
+    else
+      cf_error("Mismatched base table type");
+   }
  ;
 
 bgp_channel_opts:
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index 21052186..f13625e2 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -1018,6 +1018,23 @@ bgp_apply_mpls_labels(struct bgp_parse_state *s, rta *a, u32 *labels, uint lnum)
   }
 }
 
+static void
+bgp_apply_flow_validation(struct bgp_parse_state *s, const net_addr *n, rta *a)
+{
+  struct bgp_channel *c = s->channel;
+  int valid = rt_flowspec_check(c->base_table, c->c.table, n, a, s->proto->is_interior);
+  a->dest = valid ? RTD_NONE : RTD_UNREACHABLE;
+
+  /* Set rte.bgp.base_table later from this state variable */
+  s->base_table = c->base_table;
+
+  /* Invalidate cached rta if dest changes */
+  if (s->cached_rta && (s->cached_rta->dest != a->dest))
+  {
+    rta_free(s->cached_rta);
+    s->cached_rta = NULL;
+  }
+}
 
 static int
 bgp_match_src(struct bgp_export_state *s, int mode)
@@ -1383,6 +1400,7 @@ bgp_rte_update(struct bgp_parse_state *s, const net_addr *n, u32 path_id, rta *a
   e->pflags = 0;
   e->u.bgp.suppressed = 0;
   e->u.bgp.stale = -1;
+  e->u.bgp.base_table = s->base_table;
   rte_update3(&s->channel->c, n, e, s->last_src);
 }
 
@@ -1897,6 +1915,10 @@ bgp_decode_nlri_flow4(struct bgp_parse_state *s, byte *pos, uint len, rta *a)
     net_fill_flow4(n, px, pxlen, pos, flen);
     ADVANCE(pos, len, flen);
 
+    /* Apply validation procedure per RFC 8955 (6) */
+    if (a && s->channel->cf->validate)
+      bgp_apply_flow_validation(s, n, a);
+
     bgp_rte_update(s, n, path_id, a);
   }
 }
@@ -1985,6 +2007,10 @@ bgp_decode_nlri_flow6(struct bgp_parse_state *s, byte *pos, uint len, rta *a)
     net_fill_flow6(n, px, pxlen, pos, flen);
     ADVANCE(pos, len, flen);
 
+    /* Apply validation procedure per RFC 8955 (6) */
+    if (a && s->channel->cf->validate)
+      bgp_apply_flow_validation(s, n, a);
+
     bgp_rte_update(s, n, path_id, a);
   }
 }
@@ -2438,6 +2464,8 @@ bgp_decode_nlri(struct bgp_parse_state *s, u32 afi, byte *nlri, uint len, ea_lis
   s->last_id = 0;
   s->last_src = s->proto->p.main_source;
 
+  s->base_table = NULL;
+
   /*
    * IPv4 BGP and MP-BGP may be used together in one update, therefore we do not
    * add BA_NEXT_HOP in bgp_decode_attrs(), but we add it here independently for
diff --git a/proto/pipe/pipe.c b/proto/pipe/pipe.c
index 3532f114..f991d09a 100644
--- a/proto/pipe/pipe.c
+++ b/proto/pipe/pipe.c
@@ -81,7 +81,10 @@ pipe_rt_notify(struct proto *P, struct channel *src_ch, net *n, rte *new, rte *o
 #ifdef CONFIG_BGP
       /* Hack to cleanup cached value */
       if (e->attrs->src->proto->proto == &proto_bgp)
+      {
 	e->u.bgp.stale = -1;
+	e->u.bgp.base_table = NULL;
+      }
 #endif
 
       src = a->src;
diff --git a/test/birdtest.c b/test/birdtest.c
index a1da078f..6ad743ce 100644
--- a/test/birdtest.c
+++ b/test/birdtest.c
@@ -309,6 +309,12 @@ bt_log_suite_case_result(int result, const char *fmt, ...)
   }
 }
 
+void
+bt_reset_suite_case_timer(void)
+{
+  clock_gettime(CLOCK_MONOTONIC, &bt_suite_case_begin);
+}
+
 int
 bt_test_suite_base(int (*fn)(const void *), const char *id, const void *fn_arg, int forked, int timeout, const char *dsc, ...)
 {
@@ -501,6 +507,15 @@ bt_fmt_ipa(char *buf, size_t size, const void *data)
     bsnprintf(buf, size, "(null)");
 }
 
+void
+bt_format_net(char *buf, size_t size, const void *data)
+{
+  if (data)
+    bsnprintf(buf, size, "%N", (const net_addr *) data);
+  else
+    bsnprintf(buf, size, "(null)");
+}
+
 int
 bt_is_char(byte c)
 {
diff --git a/test/birdtest.h b/test/birdtest.h
index caec529b..ad5f8f9c 100644
--- a/test/birdtest.h
+++ b/test/birdtest.h
@@ -32,6 +32,7 @@ extern const char *bt_test_id;
 
 void bt_init(int argc, char *argv[]);
 int  bt_exit_value(void);
+void bt_reset_suite_case_timer(void);
 int bt_test_suite_base(int (*test_fn)(const void *), const char *test_id, const void *test_fn_argument, int forked, int timeout, const char *dsc, ...);
 static inline u64 bt_random(void)
 { return ((u64) random() & 0xffffffff) | ((u64) random() << 32); }
@@ -165,6 +166,8 @@ struct bt_batch {
 void bt_fmt_str(char *buf, size_t size, const void *data);
 void bt_fmt_unsigned(char *buf, size_t size, const void *data);
 void bt_fmt_ipa(char *buf, size_t size, const void *data);
+void bt_format_net(char *buf, size_t size, const void *data);
+
 int bt_assert_batch__(struct bt_batch *opts);
 int bt_is_char(byte c);