Merge branch 'mq-aggregator-for-v3' into thread-next

conf/cf-lex.l

@@ -934,6 +934,10 @@ cf_symbol_class_name(struct symbol *sym)
       return "routing table";
     case SYM_ATTRIBUTE:
       return "custom attribute";
+    case SYM_MPLS_DOMAIN:
+      return "MPLS domain";
+    case SYM_MPLS_RANGE:
+      return "MPLS label range";
     case SYM_KEYWORD:
       return "symbol";
     case SYM_CONSTANT_RANGE:

conf/conf.c

@@ -49,6 +49,7 @@
 #include "nest/route.h"
 #include "nest/protocol.h"
 #include "nest/iface.h"
+#include "nest/mpls.h"
 #include "lib/resource.h"
 #include "lib/string.h"
 #include "lib/event.h"
@@ -141,6 +142,7 @@ config_parse(struct config *c)
   cf_lex_init(0, c);
   sysdep_preconfig(c);
   protos_preconfig(c);
+  mpls_preconfig(c);
   rt_preconfig(c);
   cf_parse();
   rt_postconfig(c);
@@ -300,6 +302,7 @@ config_do_commit(struct config *c, int type)
   int force_restart = sysdep_commit(c, old_config);
   DBG("global_commit\n");
   force_restart |= global_commit(c, old_config);
+  mpls_commit(c, old_config);
   DBG("rt_commit\n");
   rt_commit(c, old_config);
   DBG("protos_commit\n");
@@ -548,6 +551,7 @@ order_shutdown(int gr)
   memcpy(c, config, sizeof(struct config));
   init_list(&c->protos);
   init_list(&c->tables);
+  init_list(&c->mpls_domains);
   init_list(&c->symbols);
   memset(c->def_tables, 0, sizeof(c->def_tables));
   c->shutdown = 1;

conf/conf.h

@@ -21,6 +21,7 @@ struct config {
   linpool *mem;				/* Linear pool containing configuration data */
   list protos;				/* Configured protocol instances (struct proto_config) */
   list tables;				/* Configured routing tables (struct rtable_config) */
+  list mpls_domains;			/* Configured MPLS domains (struct mpls_domain_config) */
   list logfiles;			/* Configured log files (sysdep) */
   list tests;				/* Configured unit tests (f_bt_test_suite) */
   list symbols;				/* Configured symbols in config order */
@@ -133,6 +134,8 @@ struct symbol {
     const struct filter *filter;	/* For SYM_FILTER */
     struct rtable_config *table;	/* For SYM_TABLE */
     struct ea_class *attribute;		/* For SYM_ATTRIBUTE */
+    struct mpls_domain_config *mpls_domain;	/* For SYM_MPLS_DOMAIN */
+    struct mpls_range_config *mpls_range;	/* For SYM_MPLS_RANGE */
     struct f_val *val;			/* For SYM_CONSTANT */
     uint offset;			/* For SYM_VARIABLE */
     const struct keyword *keyword;	/* For SYM_KEYWORD */
@@ -173,6 +176,8 @@ extern linpool *global_root_scope_linpool;
 #define SYM_ATTRIBUTE 6
 #define SYM_KEYWORD 7
 #define SYM_METHOD 8
+#define SYM_MPLS_DOMAIN 9
+#define SYM_MPLS_RANGE 10
 
 #define SYM_VARIABLE 0x100	/* 0x100-0x1ff are variable types */
 #define SYM_VARIABLE_RANGE SYM_VARIABLE ... (SYM_VARIABLE | 0xff)

conf/confbase.Y

@@ -44,6 +44,8 @@ static inline void cf_assert_symbol(const struct symbol *sym, uint class) {
     case SYM_FILTER: cf_assert(sym->class == SYM_FILTER, "Filter name required"); break;
     case SYM_TABLE: cf_assert(sym->class == SYM_TABLE, "Table name required"); break;
     case SYM_ATTRIBUTE: cf_assert(sym->class == SYM_ATTRIBUTE, "Custom attribute name required"); break;
+    case SYM_MPLS_DOMAIN: cf_assert(sym->class == SYM_MPLS_DOMAIN, "MPLS domain name required"); break;
+    case SYM_MPLS_RANGE: cf_assert(sym->class == SYM_MPLS_RANGE, "MPLS range name required"); break;
     case SYM_VARIABLE: cf_assert((sym->class & ~0xff) == SYM_VARIABLE, "Variable name required"); break;
     case SYM_CONSTANT: cf_assert((sym->class & ~0xff) == SYM_CONSTANT, "Constant name required"); break;
     default: bug("This shall not happen");

lib/ip.h

@@ -385,7 +385,13 @@ static inline ip6_addr ip6_hton(ip6_addr a)
 static inline ip6_addr ip6_ntoh(ip6_addr a)
 { return _MI6(ntohl(_I0(a)), ntohl(_I1(a)), ntohl(_I2(a)), ntohl(_I3(a))); }
 
-#define MPLS_MAX_LABEL_STACK 16
+#define MPLS_MAX_LABEL 0x100000
+
+#define MPLS_MAX_LABEL_STACK 8
+typedef struct mpls_label_stack {
+  uint len;
+  u32 stack[MPLS_MAX_LABEL_STACK];
+} mpls_label_stack;
 
 static inline int
 mpls_get(const char *buf, int buflen, u32 *stack)

lib/route.h

@@ -452,6 +452,12 @@ u32 rt_get_igp_metric(const rte *rt);
 /* From: Advertising router */
 extern struct ea_class ea_gen_from;
 
+
+/* MPLS Label, Policy and Class */
+extern struct ea_class ea_gen_mpls_label,
+       ea_gen_mpls_policy, ea_gen_mpls_class;
+
+
 /* Source: An old method to devise the route source protocol and kind.
  * To be superseded in a near future by something more informative. */
 extern struct ea_class ea_gen_source;

lib/type.h

@@ -91,6 +91,7 @@ enum btype {
 
   T_ENUM_RTS = 0x31,
   T_ENUM_SCOPE = 0x33,
+  T_ENUM_MPLS_POLICY = 0x35,
   T_ENUM_RTD = 0x37,
   T_ENUM_ROA = 0x39,
   T_ENUM_NETTYPE = 0x3b,

nest/Doc

@@ -6,6 +6,7 @@ D proto.sgml
 S proto.c
 S proto-hooks.c
 S iface.c
+S mpls.c
 S neighbor.c
 S cli.c
 S locks.c

nest/Makefile

@@ -1,7 +1,8 @@
-src := cli.c cmds.c iface.c locks.c neighbor.c password.c proto.c proto-build.c rt-attr.c rt-dev.c rt-fib.c rt-show.c rt-table.c
+src := cli.c cmds.c iface.c locks.c mpls.c neighbor.c password.c proto.c proto-build.c rt-attr.c rt-dev.c rt-fib.c rt-show.c rt-table.c
 obj := $(src-o-files)
 $(all-daemon)
 $(cf-local)
+$(conf-y-targets): $(s)mpls.Y
 
 $(o)proto-build.c: Makefile $(lastword $(MAKEFILE_LIST)) $(objdir)/.dir-stamp
 	$(E)echo GEN $@

nest/config.Y

@@ -12,6 +12,7 @@ CF_HDR
 #include "nest/rt-dev.h"
 #include "nest/password.h"
 #include "nest/cmds.h"
+#include "nest/mpls.h"
 #include "lib/lists.h"
 #include "lib/mac.h"
 
@@ -164,6 +165,7 @@ CF_KEYWORDS(GRACEFUL, RESTART, WAIT, MAX, AS)
 CF_KEYWORDS(MIN, IDLE, RX, TX, INTERVAL, MULTIPLIER, PASSIVE)
 CF_KEYWORDS(CHECK, LINK)
 CF_KEYWORDS(CORK, SORTED, TRIE, MIN, MAX, ROA, ROUTE, REFRESH, SETTLE, TIME, GC, THRESHOLD, PERIOD)
+CF_KEYWORDS(MPLS_LABEL, MPLS_POLICY, MPLS_CLASS)
 
 /* 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)
@@ -174,6 +176,7 @@ CF_ENUM(T_ENUM_SCOPE, SCOPE_, HOST, LINK, SITE, ORGANIZATION, UNIVERSE, UNDEFINE
 CF_ENUM(T_ENUM_RTD, RTD_, BLACKHOLE, UNREACHABLE, PROHIBIT)
 CF_ENUM(T_ENUM_ROA, ROA_, UNKNOWN, VALID, INVALID)
 CF_ENUM_PX(T_ENUM_AF, AF_, AFI_, IPV4, IPV6)
+CF_ENUM(T_ENUM_MPLS_POLICY, MPLS_POLICY_, NONE, STATIC, PREFIX, AGGREGATE)
 
 %type <i32> idval
 %type <f> imexport
@@ -181,7 +184,7 @@ 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 debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_mode limit_action net_type tos password_algorithm
+%type <i> proto_start debug_mask debug_list debug_flag mrtdump_mask mrtdump_list mrtdump_flag export_mode limit_action net_type net_type_base tos password_algorithm
 %type <ps> proto_patt proto_patt2
 %type <cc> channel_start proto_channel
 %type <cl> limit_spec
@@ -227,7 +230,7 @@ gr_opts: GRACEFUL RESTART WAIT expr ';' { new_config->gr_wait = $4; } ;
 
 /* Network types (for tables, channels) */
 
-net_type:
+net_type_base:
    IPV4 { $$ = NET_IP4; }
  | IPV6 { $$ = NET_IP6; }
  | IPV6 SADR { $$ = NET_IP6_SADR; }
@@ -237,6 +240,10 @@ net_type:
  | ROA6 { $$ = NET_ROA6; }
  | FLOW4{ $$ = NET_FLOW4; }
  | FLOW6{ $$ = NET_FLOW6; }
+ ;
+
+net_type:
+   net_type_base
  | MPLS { $$ = NET_MPLS; }
  ;
 
@@ -340,7 +347,7 @@ proto_item:
  ;
 
 
-channel_start: net_type
+channel_start: net_type_base
 {
   $$ = this_channel = channel_config_get(NULL, net_label[$1], $1, this_proto);
 };

nest/mpls.Y

@@ -0,0 +1,141 @@
+/*
+ *	BIRD Internet Routing Daemon -- MPLS Structures
+ *
+ *	(c) 2022 Ondrej Zajicek <santiago@crfreenet.org>
+ *	(c) 2022 CZ.NIC z.s.p.o.
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+CF_HDR
+
+#include "nest/mpls.h"
+
+CF_DEFINES
+
+static struct mpls_domain_config *this_mpls_domain;
+static struct mpls_range_config *this_mpls_range;
+
+#define MPLS_CC ((struct mpls_channel_config *) this_channel)
+
+CF_DECLS
+
+CF_KEYWORDS(MPLS, DOMAIN, LABEL, RANGE, STATIC, DYNAMIC, START, LENGTH, POLICY, PREFIX, AGGREGATE)
+
+%type <i> mpls_label_policy
+%type <cc> mpls_channel_start mpls_channel
+
+CF_GRAMMAR
+
+conf: mpls_domain;
+
+mpls_domain: mpls_domain_start mpls_domain_opt_list mpls_domain_end;
+
+mpls_domain_start: MPLS DOMAIN symbol { this_mpls_domain = mpls_domain_config_new($3); };
+
+mpls_domain_opt:
+   mpls_range
+ ;
+
+mpls_domain_opts:
+   /* empty */
+ | mpls_domain_opts mpls_domain_opt ';'
+ ;
+
+mpls_domain_opt_list:
+   /* empty */
+ | '{' mpls_domain_opts '}'
+ ;
+
+mpls_domain_end: { mpls_domain_postconfig(this_mpls_domain); this_mpls_domain = NULL; };
+
+
+mpls_range: mpls_range_start mpls_range_opt_list mpls_range_end;
+
+mpls_range_start: LABEL RANGE symbol
+{
+  if (($3->class == SYM_KEYWORD) && ($3->keyword->value == STATIC))
+    this_mpls_range = this_mpls_domain->static_range;
+  else if (($3->class == SYM_KEYWORD) && ($3->keyword->value == DYNAMIC))
+    this_mpls_range = this_mpls_domain->dynamic_range;
+  else
+    this_mpls_range = mpls_range_config_new(this_mpls_domain, $3);
+};
+
+mpls_range_opt:
+   START expr { this_mpls_range->start = $2; if ($2 >= MPLS_MAX_LABEL) cf_error("MPLS label range start must be less than 2^20"); }
+ | LENGTH expr { this_mpls_range->length = $2; if ($2 >= MPLS_MAX_LABEL) cf_error("MPLS label range length must be less than 2^20"); if (!$2) cf_error("MPLS label range length must be nonzero"); }
+ ;
+
+mpls_range_opts:
+   /* empty */
+ | mpls_range_opts mpls_range_opt ';'
+ ;
+
+mpls_range_opt_list:
+   /* empty */
+ | '{' mpls_range_opts '}'
+ ;
+
+mpls_range_end:
+{
+  struct mpls_range_config *r = this_mpls_range;
+
+  if ((r->start == (uint) -1) || (r->length == (uint) -1))
+    cf_error("MPLS label range start and length must be specified");
+
+  if (r->start + r->length > MPLS_MAX_LABEL)
+    cf_error("MPLS label range end must be less than 2^20");
+
+  this_mpls_range = NULL;
+};
+
+
+mpls_channel: mpls_channel_start mpls_channel_opt_list mpls_channel_end;
+
+mpls_channel_start: MPLS
+{
+  $$ = this_channel = channel_config_get(&channel_mpls, net_label[NET_MPLS], NET_MPLS, this_proto);
+
+  if (EMPTY_LIST(new_config->mpls_domains))
+    cf_error("No MPLS domain defined");
+
+  /* Default values for new channel */
+  if (!MPLS_CC->domain)
+  {
+    MPLS_CC->domain = cf_default_mpls_domain(new_config);
+    MPLS_CC->label_policy = MPLS_POLICY_PREFIX;
+  }
+};
+
+mpls_label_policy:
+   STATIC { $$ = MPLS_POLICY_STATIC; }
+ | PREFIX { $$ = MPLS_POLICY_PREFIX; }
+ | AGGREGATE { $$ = MPLS_POLICY_AGGREGATE; }
+ ;
+
+mpls_channel_opt:
+   channel_item
+ | DOMAIN CF_SYM_KNOWN { cf_assert_symbol($2, SYM_MPLS_DOMAIN); MPLS_CC->domain = $2->mpls_domain; }
+ | LABEL RANGE CF_SYM_KNOWN { cf_assert_symbol($3, SYM_MPLS_RANGE); MPLS_CC->range = $3->mpls_range; }
+ | LABEL RANGE STATIC  { MPLS_CC->range = MPLS_CC->domain->static_range; }
+ | LABEL RANGE DYNAMIC { MPLS_CC->range = MPLS_CC->domain->dynamic_range; }
+ | LABEL POLICY mpls_label_policy { MPLS_CC->label_policy = $3; }
+ ;
+
+mpls_channel_opts:
+   /* empty */
+ | mpls_channel_opts mpls_channel_opt ';'
+ ;
+
+mpls_channel_opt_list:
+   /* empty */
+ | '{' mpls_channel_opts '}'
+ ;
+
+mpls_channel_end: { mpls_channel_postconfig(this_channel); } channel_end;
+
+
+CF_CODE
+
+CF_END

nest/mpls.c

@@ -0,0 +1,995 @@
+/*
+ *	BIRD Internet Routing Daemon -- MPLS Structures
+ *
+ *	(c) 2022 Ondrej Zajicek <santiago@crfreenet.org>
+ *	(c) 2022 CZ.NIC z.s.p.o.
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+/**
+ * DOC: MPLS
+ *
+ * The MPLS subsystem manages MPLS labels and handles their allocation to
+ * MPLS-aware routing protocols. These labels are then attached to IP or VPN
+ * routes representing label switched paths -- LSPs. MPLS labels are also used
+ * in special MPLS routes (which use labels as network address) that are
+ * exported to MPLS routing table in kernel. The MPLS subsystem consists of MPLS
+ * domains (struct &mpls_domain), MPLS channels (struct &mpls_channel) and FEC
+ * maps (struct &mpls_fec_map).
+ *
+ * The MPLS domain represents one MPLS label address space, implements the label
+ * allocator, and handles associated configuration and management. The domain is
+ * declared in the configuration (struct &mpls_domain_config). There might be
+ * multiple MPLS domains representing separate label spaces, but in most cases
+ * one domain is enough. MPLS-aware protocols and routing tables are associated
+ * with a specific MPLS domain.
+ *
+ * The MPLS domain has configurable label ranges (struct &mpls_range), by
+ * default it has two ranges: static (16-1000) and dynamic (1000-10000). When
+ * a protocol wants to allocate labels, it first acquires a handle (struct
+ * &mpls_handle) for a specific range using mpls_new_handle(), and then it
+ * allocates labels from that with mpls_new_label(). When not needed, labels are
+ * freed by mpls_free_label() and the handle is released by mpls_free_handle().
+ * Note that all labels and handles must be freed manually.
+ *
+ * Both MPLS domain and MPLS range are reference counted, so when deconfigured
+ * they could be freed just after all labels and ranges are freed. Users are
+ * expected to hold a reference to a MPLS domain for whole time they use
+ * something from that domain (e.g. &mpls_handle), but releasing reference to
+ * a range while holding associated handle is OK.
+ *
+ * The MPLS channel is subclass of a generic protocol channel. It has two
+ * distinct purposes - to handle per-protocol MPLS configuration (e.g. which
+ * MPLS domain is associated with the protocol, which label range is used by the
+ * protocol), and to announce MPLS routes to a routing table (as a regular
+ * protocol channel).
+ *
+ * The FEC map is a helper structure that maps forwarding equivalent classes
+ * (FECs) to MPLS labels. It is an internal matter of a routing protocol how to
+ * assign meaning to allocated labels, announce LSP routes and associated MPLS
+ * routes (i.e. ILM entries). But the common behavior is implemented in the FEC
+ * map, which can be used by the protocols that work with IP-prefix-based FECs.
+ *
+ * The FEC map keeps hash tables of FECs (struct &mpls_fec) based on network
+ * prefix, next hop eattr and assigned label. It has three labeling policies:
+ * static assignment (%MPLS_POLICY_STATIC), per-prefix policy (%MPLS_POLICY_PREFIX),
+ * and aggregating policy (%MPLS_POLICY_AGGREGATE). In per-prefix policy, each
+ * distinct LSP is a separate FEC and uses a separate label, which is kept even
+ * if the next hop of the LSP changes. In aggregating policy, LSPs with a same
+ * next hop form one FEC and use one label, but when a next hop (or remote
+ * label) of such LSP changes then the LSP must be moved to a different FEC and
+ * assigned a different label.
+ *
+ * The overall process works this way: A protocol wants to announce a LSP route,
+ * it does that by announcing e.g. IP route with %EA_MPLS_POLICY attribute.
+ * After the route is accepted by filters (which may also change the policy
+ * attribute or set a static label), the mpls_handle_rte() is called from
+ * rte_update2(), which applies selected labeling policy, finds existing FEC or
+ * creates a new FEC (which includes allocating new label and announcing related
+ * MPLS route by mpls_announce_fec()), and attach FEC label to the LSP route.
+ * After that, the LSP route is stored in routing table by rte_recalculate().
+ * Changes in routing tables trigger mpls_rte_insert() and mpls_rte_remove()
+ * hooks, which refcount FEC structures and possibly trigger removal of FECs
+ * and withdrawal of MPLS routes.
+ *
+ * TODO:
+ *  - show mpls labels CLI command
+ *  - label range non-intersection check
+ *  - better range reconfigurations (allow reduce ranges over unused labels)
+ *  - protocols should do route refresh instead of resetart when reconfiguration
+ *    requires changing labels (e.g. different label range)
+ *  - registering static allocations
+ *  - checking range in static allocations
+ *  - special handling of reserved labels
+ */
+
+#include "nest/bird.h"
+#include "nest/route.h"
+#include "nest/mpls.h"
+
+static struct mpls_range *mpls_new_range(struct mpls_domain *m, struct mpls_range_config *cf);
+static struct mpls_range *mpls_find_range_(list *l, const char *name);
+static int mpls_reconfigure_range(struct mpls_domain *m, struct mpls_range *r, struct mpls_range_config *cf);
+static void mpls_remove_range(struct mpls_range *r);
+
+
+/*
+ *	MPLS domain
+ */
+
+list mpls_domains;
+
+void
+mpls_init(void)
+{
+  init_list(&mpls_domains);
+}
+
+struct mpls_domain_config *
+mpls_domain_config_new(struct symbol *s)
+{
+  struct mpls_domain_config *mc = cfg_allocz(sizeof(struct mpls_domain_config));
+  struct mpls_range_config *rc;
+
+  cf_define_symbol(new_config, s, SYM_MPLS_DOMAIN, mpls_domain, mc);
+  mc->name = s->name;
+  init_list(&mc->ranges);
+
+  /* Predefined static range */
+  rc = mpls_range_config_new(mc, NULL);
+  rc->name = "static";
+  rc->start = 16;
+  rc->length = 984;
+  mc->static_range = rc;
+
+  /* Predefined dynamic range */
+  rc = mpls_range_config_new(mc, NULL);
+  rc->name = "dynamic";
+  rc->start = 1000;
+  rc->length = 9000;
+  mc->dynamic_range = rc;
+
+  add_tail(&new_config->mpls_domains, &mc->n);
+
+  return mc;
+}
+
+void
+mpls_domain_postconfig(struct mpls_domain_config *cf UNUSED)
+{
+  /* Add label range non-intersection check */
+}
+
+static struct mpls_domain *
+mpls_new_domain(struct mpls_domain_config *cf)
+{
+  struct pool *p = rp_new(&root_pool, the_bird_domain.the_bird, "MPLS domain");
+  struct mpls_domain *m = mb_allocz(p, sizeof(struct mpls_domain));
+
+  m->cf = cf;
+  m->name = cf->name;
+  m->pool = p;
+
+  lmap_init(&m->labels, p);
+  lmap_set(&m->labels, 0);
+
+  init_list(&m->ranges);
+  init_list(&m->handles);
+
+  struct mpls_range_config *rc;
+  WALK_LIST(rc, cf->ranges)
+    mpls_new_range(m, rc);
+
+  add_tail(&mpls_domains, &m->n);
+  cf->domain = m;
+
+  return m;
+}
+
+static struct mpls_domain *
+mpls_find_domain_(list *l, const char *name)
+{
+  struct mpls_domain *m;
+
+  WALK_LIST(m, *l)
+    if (!strcmp(m->name, name))
+      return m;
+
+  return NULL;
+}
+
+static int
+mpls_reconfigure_domain(struct mpls_domain *m, struct mpls_domain_config *cf)
+{
+  cf->domain = m;
+  m->cf->domain = NULL;
+  m->cf = cf;
+  m->name = cf->name;
+
+  /* Reconfigure label ranges */
+  list old_ranges;
+  init_list(&old_ranges);
+  add_tail_list(&old_ranges, &m->ranges);
+  init_list(&m->ranges);
+
+  struct mpls_range_config *rc;
+  WALK_LIST(rc, cf->ranges)
+  {
+    struct mpls_range *r = mpls_find_range_(&old_ranges, rc->name);
+
+    if (r && mpls_reconfigure_range(m, r, rc))
+    {
+      rem_node(&r->n);
+      add_tail(&m->ranges, &r->n);
+      continue;
+    }
+
+    mpls_new_range(m, rc);
+  }
+
+  struct mpls_range *r, *r2;
+  WALK_LIST_DELSAFE(r, r2, old_ranges)
+    mpls_remove_range(r);
+
+  add_tail_list(&m->ranges, &old_ranges);
+
+  return 1;
+}
+
+static void
+mpls_free_domain(struct mpls_domain *m)
+{
+  ASSERT(m->use_count == 0);
+  ASSERT(m->label_count == 0);
+  ASSERT(EMPTY_LIST(m->handles));
+
+  struct config *cfg = m->removed;
+
+  m->cf->domain = NULL;
+  rem_node(&m->n);
+  rfree(m->pool);
+
+  config_del_obstacle(cfg);
+}
+
+static void
+mpls_remove_domain(struct mpls_domain *m, struct config *cfg)
+{
+  m->removed = cfg;
+  config_add_obstacle(cfg);
+
+  if (!m->use_count)
+    mpls_free_domain(m);
+}
+
+void
+mpls_lock_domain(struct mpls_domain *m)
+{
+  m->use_count++;
+}
+
+void
+mpls_unlock_domain(struct mpls_domain *m)
+{
+  ASSERT(m->use_count > 0);
+
+  m->use_count--;
+  if (!m->use_count && m->removed)
+    mpls_free_domain(m);
+}
+
+void
+mpls_preconfig(struct config *c)
+{
+  init_list(&c->mpls_domains);
+}
+
+void
+mpls_commit(struct config *new, struct config *old)
+{
+  list old_domains;
+  init_list(&old_domains);
+  add_tail_list(&old_domains, &mpls_domains);
+  init_list(&mpls_domains);
+
+  struct mpls_domain_config *mc;
+  WALK_LIST(mc, new->mpls_domains)
+  {
+    struct mpls_domain *m = mpls_find_domain_(&old_domains, mc->name);
+
+    if (m && mpls_reconfigure_domain(m, mc))
+    {
+      rem_node(&m->n);
+      add_tail(&mpls_domains, &m->n);
+      continue;
+    }
+
+    mpls_new_domain(mc);
+  }
+
+  struct mpls_domain *m, *m2;
+  WALK_LIST_DELSAFE(m, m2, old_domains)
+    mpls_remove_domain(m, old);
+
+  add_tail_list(&mpls_domains, &old_domains);
+}
+
+
+/*
+ *	MPLS range
+ */
+
+struct mpls_range_config *
+mpls_range_config_new(struct mpls_domain_config *mc, struct symbol *s)
+{
+  struct mpls_range_config *rc = cfg_allocz(sizeof(struct mpls_range_config));
+
+  if (s)
+    cf_define_symbol(new_config, s, SYM_MPLS_RANGE, mpls_range, rc);
+
+  rc->domain = mc;
+  rc->name = s ? s->name : NULL;
+  rc->start = (uint) -1;
+  rc->length = (uint) -1;
+
+  add_tail(&mc->ranges, &rc->n);
+
+  return rc;
+}
+
+static struct mpls_range *
+mpls_new_range(struct mpls_domain *m, struct mpls_range_config *cf)
+{
+  struct mpls_range *r = mb_allocz(m->pool, sizeof(struct mpls_range));
+
+  r->cf = cf;
+  r->name = cf->name;
+  r->lo = cf->start;
+  r->hi = cf->start + cf->length;
+
+  add_tail(&m->ranges, &r->n);
+  cf->range = r;
+
+  return r;
+}
+
+static struct mpls_range *
+mpls_find_range_(list *l, const char *name)
+{
+  struct mpls_range *r;
+
+  WALK_LIST(r, *l)
+    if (!strcmp(r->name, name))
+      return r;
+
+  return NULL;
+}
+
+static int
+mpls_reconfigure_range(struct mpls_domain *m UNUSED, struct mpls_range *r, struct mpls_range_config *cf)
+{
+  if ((cf->start > r->lo) || (cf->start + cf->length < r->hi))
+    return 0;
+
+  cf->range = r;
+  r->cf->range = NULL;
+  r->cf = cf;
+  r->name = cf->name;
+  r->lo = cf->start;
+  r->hi = cf->start + cf->length;
+
+  return 1;
+}
+
+static void
+mpls_free_range(struct mpls_range *r)
+{
+  ASSERT(r->use_count == 0);
+  ASSERT(r->label_count == 0);
+
+  r->cf->range = NULL;
+  rem_node(&r->n);
+  mb_free(r);
+}
+
+static void
+mpls_remove_range(struct mpls_range *r)
+{
+  r->removed = 1;
+
+  if (!r->use_count)
+    mpls_free_range(r);
+}
+
+void
+mpls_lock_range(struct mpls_range *r)
+{
+  r->use_count++;
+}
+
+void
+mpls_unlock_range(struct mpls_range *r)
+{
+  ASSERT(r->use_count > 0);
+
+  r->use_count--;
+  if (!r->use_count && r->removed)
+    mpls_free_range(r);
+}
+
+
+/*
+ *	MPLS handle
+ */
+
+struct mpls_handle *
+mpls_new_handle(struct mpls_domain *m, struct mpls_range *r)
+{
+  struct mpls_handle *h = mb_allocz(m->pool, sizeof(struct mpls_handle));
+
+  h->range = r;
+  mpls_lock_range(h->range);
+
+  add_tail(&m->handles, &h->n);
+
+  return h;
+}
+
+void
+mpls_free_handle(struct mpls_domain *m UNUSED, struct mpls_handle *h)
+{
+  ASSERT(h->label_count == 0);
+
+  mpls_unlock_range(h->range);
+  rem_node(&h->n);
+  mb_free(h);
+}
+
+
+/*
+ *	MPLS label
+ */
+
+uint
+mpls_new_label(struct mpls_domain *m, struct mpls_handle *h)
+{
+  struct mpls_range *r = h->range;
+  uint n = lmap_first_zero_in_range(&m->labels, r->lo, r->hi);
+
+  if (n >= r->hi)
+    return 0;
+
+  m->label_count++;
+  r->label_count++;
+  h->label_count++;
+
+  lmap_set(&m->labels, n);
+  return n;
+}
+
+void
+mpls_free_label(struct mpls_domain *m, struct mpls_handle *h, uint n)
+{
+  struct mpls_range *r = h->range;
+
+  ASSERT(lmap_test(&m->labels, n));
+  lmap_clear(&m->labels, n);
+
+  ASSERT(m->label_count);
+  m->label_count--;
+
+  ASSERT(r->label_count);
+  r->label_count--;
+
+  ASSERT(h->label_count);
+  h->label_count--;
+}
+
+
+/*
+ *	MPLS channel
+ */
+
+static void
+mpls_channel_init(struct channel *C, struct channel_config *CC)
+{
+  struct mpls_channel *c = (void *) C;
+  struct mpls_channel_config *cc = (void *) CC;
+
+  c->domain = cc->domain->domain;
+  c->range = cc->range->range;
+  c->label_policy = cc->label_policy;
+}
+
+static int
+mpls_channel_start(struct channel *C)
+{
+  struct mpls_channel *c = (void *) C;
+
+  mpls_lock_domain(c->domain);
+  mpls_lock_range(c->range);
+
+  return 0;
+}
+
+/*
+static void
+mpls_channel_shutdown(struct channel *C)
+{
+  struct mpls_channel *c = (void *) C;
+
+}
+*/
+
+static void
+mpls_channel_cleanup(struct channel *C)
+{
+  struct mpls_channel *c = (void *) C;
+
+  mpls_unlock_range(c->range);
+  mpls_unlock_domain(c->domain);
+}
+
+static int
+mpls_channel_reconfigure(struct channel *C, struct channel_config *CC, int *import_changed UNUSED, int *export_changed UNUSED)
+{
+  struct mpls_channel *c = (void *) C;
+  struct mpls_channel_config *new = (void *) CC;
+
+  if ((new->domain->domain != c->domain) ||
+      (new->range->range != c->range) ||
+      (new->label_policy != c->label_policy))
+    return 0;
+
+  return 1;
+}
+
+void
+mpls_channel_postconfig(struct channel_config *CC)
+{
+  struct mpls_channel_config *cc = (void *) CC;
+
+  if (!cc->domain)
+    cf_error("MPLS domain not specified");
+
+  if (!cc->range)
+    cc->range = (cc->label_policy == MPLS_POLICY_STATIC) ?
+      cc->domain->static_range : cc->domain->dynamic_range;
+
+  if (cc->range->domain != cc->domain)
+    cf_error("MPLS label range from different MPLS domain");
+
+  if (!cc->c.table)
+    cf_error("Routing table not specified");
+}
+
+struct channel_class channel_mpls = {
+  .channel_size =	sizeof(struct mpls_channel),
+  .config_size =	sizeof(struct mpls_channel_config),
+  .init =		mpls_channel_init,
+  .start =		mpls_channel_start,
+//  .shutdown =		mpls_channel_shutdown,
+  .cleanup =		mpls_channel_cleanup,
+  .reconfigure =	mpls_channel_reconfigure,
+};
+
+
+/*
+ *	MPLS FEC map
+ */
+
+#define NET_KEY(fec)		fec->net, fec->path_id, fec->hash
+#define NET_NEXT(fec)		fec->next_k
+#define NET_EQ(n1,i1,h1,n2,i2,h2) h1 == h2 && i1 == i2 && net_equal(n1, n2)
+#define NET_FN(n,i,h)		h
+
+#define NET_REHASH		mpls_net_rehash
+#define NET_PARAMS		/8, *2, 2, 2, 8, 24
+
+
+#define RTA_KEY(fec)		fec->rta
+#define RTA_NEXT(fec)		fec->next_k
+#define RTA_EQ(r1,r2)		r1 == r2
+#define RTA_FN(r)		r->hash_key
+
+#define RTA_REHASH		mpls_rta_rehash
+#define RTA_PARAMS		/8, *2, 2, 2, 8, 24
+
+
+#define LABEL_KEY(fec)		fec->label
+#define LABEL_NEXT(fec)		fec->next_l
+#define LABEL_EQ(l1,l2)		l1 == l2
+#define LABEL_FN(l)		u32_hash(l)
+
+#define LABEL_REHASH		mpls_label_rehash
+#define LABEL_PARAMS		/8, *2, 2, 2, 8, 24
+
+
+HASH_DEFINE_REHASH_FN(NET, struct mpls_fec)
+HASH_DEFINE_REHASH_FN(RTA, struct mpls_fec)
+HASH_DEFINE_REHASH_FN(LABEL, struct mpls_fec)
+
+
+static void mpls_withdraw_fec(struct mpls_fec_map *m, struct mpls_fec *fec);
+static struct ea_storage * mpls_get_key_attrs(struct mpls_fec_map *m, ea_list *src);
+
+struct mpls_fec_map *
+mpls_fec_map_new(pool *pp, struct channel *C, uint rts)
+{
+  struct pool *p = rp_new(pp, the_bird_domain.the_bird, "MPLS FEC map");
+  struct mpls_fec_map *m = mb_allocz(p, sizeof(struct mpls_fec_map));
+  struct mpls_channel *c = (void *) C;
+
+  m->pool = p;
+  m->channel = C;
+
+  m->domain = c->domain;
+  mpls_lock_domain(m->domain);
+
+  m->handle = mpls_new_handle(c->domain, c->range);
+
+  /* net_hash and rta_hash are initialized on-demand */
+  HASH_INIT(m->label_hash, m->pool, 4);
+
+  m->mpls_rts = rts;
+
+  return m;
+}
+
+void
+mpls_fec_map_free(struct mpls_fec_map *m)
+{
+  /* Free stored rtas */
+  if (m->attrs_hash.data)
+  {
+    HASH_WALK(m->attrs_hash, next_k, fec)
+    {
+      ea_free(fec->rta->l);
+      fec->rta = NULL;
+    }
+    HASH_WALK_END;
+  }
+
+  /* Free allocated labels */
+  HASH_WALK(m->label_hash, next_l, fec)
+  {
+    if (fec->policy != MPLS_POLICY_STATIC)
+      mpls_free_label(m->domain, m->handle, fec->label);
+  }
+  HASH_WALK_END;
+
+  mpls_free_handle(m->domain, m->handle);
+  mpls_unlock_domain(m->domain);
+
+  rfree(m->pool);
+}
+
+static slab *
+mpls_slab(struct mpls_fec_map *m, uint type)
+{
+  ASSERT(type <= NET_VPN6);
+  int pos = type ? (type - 1) : 0;
+
+  if (!m->slabs[pos])
+    m->slabs[pos] = sl_new(m->pool, sizeof(struct mpls_fec) + net_addr_length[pos + 1]);
+
+  return m->slabs[pos];
+}
+
+struct mpls_fec *
+mpls_find_fec_by_label(struct mpls_fec_map *m, u32 label)
+{
+  return HASH_FIND(m->label_hash, LABEL, label);
+}
+
+struct mpls_fec *
+mpls_get_fec_by_label(struct mpls_fec_map *m, u32 label)
+{
+  struct mpls_fec *fec = HASH_FIND(m->label_hash, LABEL, label);
+
+  if (fec)
+    return fec;
+
+  fec = sl_allocz(mpls_slab(m, 0));
+
+  fec->label = label;
+  fec->policy = MPLS_POLICY_STATIC;
+
+  DBG("New FEC lab %u\n", fec->label);
+
+  HASH_INSERT2(m->label_hash, LABEL, m->pool, fec);
+
+  return fec;
+}
+
+struct mpls_fec *
+mpls_get_fec_by_net(struct mpls_fec_map *m, const net_addr *net, u32 path_id)
+{
+  if (!m->net_hash.data)
+    HASH_INIT(m->net_hash, m->pool, 4);
+
+  u32 hash = net_hash(net) ^ u32_hash(path_id);
+  struct mpls_fec *fec = HASH_FIND(m->net_hash, NET, net, path_id, hash);
+
+  if (fec)
+    return fec;
+
+  fec = sl_allocz(mpls_slab(m, net->type));
+
+  fec->hash = hash;
+  fec->path_id = path_id;
+  net_copy(fec->net, net);
+
+  fec->label = mpls_new_label(m->domain, m->handle);
+  fec->policy = MPLS_POLICY_PREFIX;
+
+  DBG("New FEC net %u\n", fec->label);
+
+  HASH_INSERT2(m->net_hash, NET, m->pool, fec);
+  HASH_INSERT2(m->label_hash, LABEL, m->pool, fec);
+
+  return fec;
+}
+
+struct mpls_fec *
+mpls_get_fec_by_destination(struct mpls_fec_map *m, ea_list *dest)
+{
+  if (!m->attrs_hash.data)
+    HASH_INIT(m->attrs_hash, m->pool, 4);
+
+  struct ea_storage *rta = mpls_get_key_attrs(m, dest);
+  u32 hash = rta->hash_key;
+  struct mpls_fec *fec = HASH_FIND(m->attrs_hash, RTA, rta);
+
+  if (fec)
+  {
+    ea_free(rta->l);
+    return fec;
+  }
+
+  fec = sl_allocz(mpls_slab(m, 0));
+
+  fec->hash = hash;
+  fec->rta = rta;
+
+  fec->label = mpls_new_label(m->domain, m->handle);
+  fec->policy = MPLS_POLICY_AGGREGATE;
+
+  DBG("New FEC rta %u\n", fec->label);
+
+  HASH_INSERT2(m->attrs_hash, RTA, m->pool, fec);
+  HASH_INSERT2(m->label_hash, LABEL, m->pool, fec);
+
+  return fec;
+}
+
+void
+mpls_free_fec(struct mpls_fec_map *m, struct mpls_fec *fec)
+{
+  if (fec->state != MPLS_FEC_DOWN)
+    mpls_withdraw_fec(m, fec);
+
+  DBG("Free FEC %u\n", fec->label);
+
+  mpls_free_label(m->domain, m->handle, fec->label);
+  HASH_REMOVE2(m->label_hash, LABEL, m->pool, fec);
+
+  switch (fec->policy)
+  {
+  case MPLS_POLICY_STATIC:
+    break;
+
+  case MPLS_POLICY_PREFIX:
+    HASH_REMOVE2(m->net_hash, NET, m->pool, fec);
+    break;
+
+  case MPLS_POLICY_AGGREGATE:
+    ea_free(fec->rta->l);
+    HASH_REMOVE2(m->attrs_hash, RTA, m->pool, fec);
+    break;
+
+  default:
+    bug("Unknown fec type");
+  }
+
+  sl_free(fec);
+}
+
+static inline void mpls_lock_fec(struct mpls_fec_map *x UNUSED, struct mpls_fec *fec)
+{ if (fec) fec->uc++; }
+
+static inline void mpls_unlock_fec(struct mpls_fec_map *x, struct mpls_fec *fec)
+{ if (fec && !--fec->uc) mpls_free_fec(x, fec); }
+
+struct mpls_fec_tmp_lock {
+  resource r;
+  struct mpls_fec_map *m;
+  struct mpls_fec *fec;
+};
+
+static void
+mpls_fec_tmp_lock_free(resource *r)
+{
+  struct mpls_fec_tmp_lock *l = SKIP_BACK(struct mpls_fec_tmp_lock, r, r);
+  mpls_unlock_fec(l->m, l->fec);
+}
+
+static void
+mpls_fec_tmp_lock_dump(resource *r, unsigned indent UNUSED)
+{
+  struct mpls_fec_tmp_lock *l = SKIP_BACK(struct mpls_fec_tmp_lock, r, r);
+  debug("map=%p fec=%p label=%u", l->m, l->fec, l->fec->label);
+}
+
+static struct resclass mpls_fec_tmp_lock_class = {
+  .name = "Temporary MPLS FEC Lock",
+  .size = sizeof(struct mpls_fec_tmp_lock),
+  .free = mpls_fec_tmp_lock_free,
+  .dump = mpls_fec_tmp_lock_dump,
+};
+
+static void
+mpls_lock_fec_tmp(struct mpls_fec_map *m, struct mpls_fec *fec)
+{
+  if (!fec)
+    return;
+
+  fec->uc++;
+
+  struct mpls_fec_tmp_lock *l = ralloc(tmp_res.pool, &mpls_fec_tmp_lock_class);
+  l->m = m;
+  l->fec = fec;
+}
+
+static inline void
+mpls_damage_fec(struct mpls_fec_map *m UNUSED, struct mpls_fec *fec)
+{
+  if (fec->state == MPLS_FEC_CLEAN)
+    fec->state = MPLS_FEC_DIRTY;
+}
+
+static struct ea_storage *
+mpls_get_key_attrs(struct mpls_fec_map *m, ea_list *src)
+{
+  EA_LOCAL_LIST(4) ea = {
+    .l.flags = EALF_SORTED,
+  };
+
+  uint last_id = 0;
+  #define PUT_ATTR(cls)	do { \
+    ASSERT_DIE(last_id < (cls)->id); \
+    last_id = (cls)->id; \
+    eattr *a = ea_find_by_class(src, (cls)); \
+    if (a) ea.a[ea.l.count++] = *a; \
+  } while (0)
+
+  PUT_ATTR(&ea_gen_nexthop);
+  PUT_ATTR(&ea_gen_hostentry);
+  ea.a[ea.l.count++] = EA_LITERAL_EMBEDDED(&ea_gen_source, 0, m->mpls_rts);
+  PUT_ATTR(&ea_gen_mpls_class);
+
+  return ea_get_storage(ea_lookup(&ea.l, 0));
+}
+
+static void
+mpls_announce_fec(struct mpls_fec_map *m, struct mpls_fec *fec, ea_list *src)
+{
+  /* Check existence of hostentry */
+  const struct eattr *heea = ea_find_by_class(src, &ea_gen_hostentry);
+  if (heea) {
+    /* The same hostentry, but different dependent table */
+    struct hostentry_adata *head = SKIP_BACK(struct hostentry_adata, ad, heea->u.ad);
+    struct hostentry *he = head->he;
+    ea_set_hostentry(&src, m->channel->table, he->owner, he->addr, he->link,
+	HOSTENTRY_LABEL_COUNT(head), head->labels);
+  }
+
+  net_addr_mpls n = NET_ADDR_MPLS(fec->label);
+
+  rte e = {
+    .src = m->channel->proto->main_source,
+    .attrs = src,
+  };
+
+  fec->state = MPLS_FEC_CLEAN;
+  rte_update(m->channel, (net_addr *) &n, &e, m->channel->proto->main_source);
+}
+
+static void
+mpls_withdraw_fec(struct mpls_fec_map *m, struct mpls_fec *fec)
+{
+  net_addr_mpls n = NET_ADDR_MPLS(fec->label);
+
+  fec->state = MPLS_FEC_DOWN;
+  rte_update(m->channel, (net_addr *) &n, NULL, m->channel->proto->main_source);
+}
+
+static void
+mpls_apply_fec(rte *r, struct mpls_fec *fec)
+{
+  ea_set_attr_u32(&r->attrs, &ea_gen_mpls_label, 0, fec->label);
+  ea_set_attr_u32(&r->attrs, &ea_gen_mpls_policy, 0, fec->policy);
+}
+
+
+void
+mpls_handle_rte(struct mpls_fec_map *m, const net_addr *n, rte *r)
+{
+  struct mpls_fec *fec = NULL;
+
+  /* Select FEC for route */
+  uint policy = ea_get_int(r->attrs, &ea_gen_mpls_policy, 0);
+  switch (policy)
+  {
+  case MPLS_POLICY_NONE:
+    return;
+
+  case MPLS_POLICY_STATIC:;
+    uint label = ea_get_int(r->attrs, &ea_gen_mpls_label, 0);
+
+    if (label < 16)
+      return;
+
+    fec = mpls_get_fec_by_label(m, label);
+    mpls_damage_fec(m, fec);
+    break;
+
+  case MPLS_POLICY_PREFIX:
+    fec = mpls_get_fec_by_net(m, n, r->src->private_id);
+    mpls_damage_fec(m, fec);
+    break;
+
+  case MPLS_POLICY_AGGREGATE:
+    fec = mpls_get_fec_by_destination(m, r->attrs);
+    break;
+
+  default:
+    log(L_WARN "Route %N has invalid MPLS policy %u", n, policy);
+    return;
+  }
+
+  /* Temporarily lock FEC */
+  mpls_lock_fec_tmp(m, fec);
+
+  /* Apply FEC label to route */
+  mpls_apply_fec(r, fec);
+
+  /* Announce MPLS rule for new/updated FEC */
+  if (fec->state != MPLS_FEC_CLEAN)
+    mpls_announce_fec(m, fec, r->attrs);
+}
+
+static inline struct mpls_fec_tmp_lock
+mpls_rte_get_fec_lock(const rte *r)
+{
+  struct mpls_fec_tmp_lock mt = {
+    .m = SKIP_BACK(struct proto, sources, r->src->owner)->mpls_map,
+  };
+
+  if (!mt.m)
+    return mt;
+
+  uint label = ea_get_int(r->attrs, &ea_gen_mpls_label, 0);
+  if (label < 16)
+    return mt;
+
+  mt.fec = mpls_find_fec_by_label(mt.m, label);
+  return mt;
+}
+
+void
+mpls_rte_preimport(rte *new, const rte *old)
+{
+  struct mpls_fec_tmp_lock new_mt = {}, old_mt = {};
+
+  if (new)
+    new_mt = mpls_rte_get_fec_lock(new);
+
+  if (old)
+    old_mt = mpls_rte_get_fec_lock(old);
+
+  if (new_mt.fec == old_mt.fec)
+    return;
+
+  if (new_mt.fec)
+    mpls_lock_fec(new_mt.m, new_mt.fec);
+
+  if (old_mt.fec)
+    mpls_unlock_fec(old_mt.m, old_mt.fec);
+}
+
+struct ea_class ea_gen_mpls_policy = {
+  .name = "mpls_policy",
+  .type = T_ENUM_MPLS_POLICY,
+};
+
+struct ea_class ea_gen_mpls_class = {
+  .name = "mpls_class",
+  .type = T_INT,
+};
+
+struct ea_class ea_gen_mpls_label = {
+  .name = "mpls_label",
+  .type = T_INT,
+};

nest/mpls.h

@@ -0,0 +1,166 @@
+/*
+ *	BIRD Internet Routing Daemon -- MPLS Structures
+ *
+ *	(c) 2022 Ondrej Zajicek <santiago@crfreenet.org>
+ *	(c) 2022 CZ.NIC z.s.p.o.
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_MPLS_H_
+#define _BIRD_MPLS_H_
+
+#include "nest/bird.h"
+#include "lib/bitmap.h"
+#include "lib/hash.h"
+#include "nest/route.h"
+#include "nest/protocol.h"
+
+
+#define MPLS_POLICY_NONE	0
+#define MPLS_POLICY_STATIC	1
+#define MPLS_POLICY_PREFIX	2
+#define MPLS_POLICY_AGGREGATE	3
+
+#define MPLS_FEC_DOWN		0
+#define MPLS_FEC_CLEAN		1
+#define MPLS_FEC_DIRTY		2
+
+
+struct mpls_domain_config {
+  node n;				/* Node in config.mpls_domains */
+  struct mpls_domain *domain;		/* Our instance */
+  const char *name;
+
+  list ranges;				/* List of label ranges (struct mpls_range_config) */
+  struct mpls_range_config *static_range;  /* Default static label range */
+  struct mpls_range_config *dynamic_range; /* Default dynamic label range */
+};
+
+struct mpls_domain {
+  node n;				/* Node in global list of MPLS domains (mpls_domains) */
+  struct mpls_domain_config *cf;	/* Our config */
+  const char *name;
+  pool *pool;				/* Pool for the domain and associated objects */
+
+  struct lmap labels;			/* Bitmap of allocated labels */
+  uint label_count;			/* Number of allocated labels */
+  uint use_count;			/* Reference counter */
+
+  struct config *removed;		/* Deconfigured, waiting for zero use_count,
+					   while keeping config obstacle */
+
+  list ranges;				/* List of label ranges (struct mpls_range) */
+  list handles;				/* List of label handles (struct mpls_handle) */
+};
+
+struct mpls_range_config {
+  node n;				/* Node in mpls_domain_config.ranges */
+  struct mpls_range *range;		/* Our instance */
+  struct mpls_domain_config *domain;	/* Parent MPLS domain */
+  const char *name;
+
+  uint start;				/* Label range start, (uint) -1 for undefined */
+  uint length;				/* Label range length, (uint) -1 for undefined */
+};
+
+struct mpls_range {
+  node n;				/* Node in mpls_domain.ranges */
+  struct mpls_range_config *cf;		/* Our config */
+  const char *name;
+
+  uint lo, hi;				/* Label range interval */
+  uint label_count;			/* Number of allocated labels */
+  uint use_count;			/* Reference counter */
+  u8 removed;				/* Deconfigured, waiting for zero use_count */
+};
+
+struct mpls_handle {
+  node n;				/* Node in mpls_domain.handles */
+
+  struct mpls_range *range;		/* Associated range, keeping reference */
+  uint label_count;			/* Number of allocated labels */
+};
+
+
+void mpls_init(void);
+struct mpls_domain_config * mpls_domain_config_new(struct symbol *s);
+void mpls_domain_postconfig(struct mpls_domain_config *cf);
+struct mpls_range_config * mpls_range_config_new(struct mpls_domain_config *m, struct symbol *s);
+void mpls_preconfig(struct config *c);
+void mpls_commit(struct config *new, struct config *old);
+uint mpls_new_label(struct mpls_domain *m, struct mpls_handle *h);
+void mpls_free_label(struct mpls_domain *m, struct mpls_handle *h, uint n);
+
+static inline struct mpls_domain_config *cf_default_mpls_domain(struct config *cfg)
+{ return EMPTY_LIST(cfg->mpls_domains) ? NULL : HEAD(cfg->mpls_domains); }
+
+
+struct mpls_channel_config {
+  struct channel_config c;
+
+  struct mpls_domain_config *domain;
+  struct mpls_range_config *range;
+
+  uint label_policy;
+};
+
+struct mpls_channel {
+  struct channel c;
+
+  struct mpls_domain *domain;
+  struct mpls_range *range;
+
+  uint label_policy;
+};
+
+
+void mpls_channel_postconfig(struct channel_config *CF);
+extern struct channel_class channel_mpls;
+
+
+struct mpls_fec {
+  u32 label;				/* Label for FEC */
+  u32 hash;				/* Hash for primary key (net / rta) */
+  u32 uc;				/* Number of LSPs for FEC */
+  union {				/* Extension part of key */
+    u32 path_id;			/* Source path_id */
+  };
+
+  u8 state;				/* FEC state (MPLS_FEC_*) */
+  u8 policy;				/* Label policy (MPLS_POLICY_*) */
+
+  struct mpls_fec *next_k;		/* Next in mpls_fec.net_hash/rta_hash */
+  struct mpls_fec *next_l;		/* Next in mpls_fec.label_hash */
+  union {				/* Primary key */
+    struct ea_storage *rta;
+    net_addr net[0];
+  };
+};
+
+struct mpls_fec_map {
+  pool *pool;				/* Pool for FEC map */
+  slab *slabs[4];			/* Slabs for FEC allocation */
+  HASH(struct mpls_fec) net_hash;	/* Hash table for MPLS_POLICY_PREFIX FECs */
+  HASH(struct mpls_fec) attrs_hash;	/* Hash table for MPLS_POLICY_AGGREGATE FECs */
+  HASH(struct mpls_fec) label_hash;	/* Hash table for FEC lookup by label */
+
+  struct channel *channel;		/* MPLS channel for FEC announcement */
+  struct mpls_domain *domain;		/* MPLS domain, keeping reference */
+  struct mpls_handle *handle;		/* Handle for allocation of labels */
+
+  u8 mpls_rts;				/* Source value used for MPLS routes (RTS_*) */
+};
+
+
+struct mpls_fec_map *mpls_fec_map_new(pool *p, struct channel *c, uint rts);
+void mpls_fec_map_free(struct mpls_fec_map *m);
+struct mpls_fec *mpls_find_fec_by_label(struct mpls_fec_map *x, u32 label);
+struct mpls_fec *mpls_get_fec_by_label(struct mpls_fec_map *m, u32 label);
+struct mpls_fec *mpls_get_fec_by_net(struct mpls_fec_map *m, const net_addr *net, u32 path_id);
+struct mpls_fec *mpls_get_fec_by_destination(struct mpls_fec_map *m, ea_list *dest);
+void mpls_free_fec(struct mpls_fec_map *x, struct mpls_fec *fec);
+void mpls_handle_rte(struct mpls_fec_map *m, const net_addr *n, rte *r);
+void mpls_rte_preimport(rte *new, const rte *old);
+
+#endif

nest/proto.c

@@ -18,6 +18,7 @@
 #include "conf/conf.h"
 #include "nest/route.h"
 #include "nest/iface.h"
+#include "nest/mpls.h"
 #include "nest/cli.h"
 #include "filter/filter.h"
 #include "filter/f-inst.h"
@@ -1283,7 +1284,7 @@ channel_config_new(const struct channel_class *cc, const char *name, uint net_ty
     if (!net_val_match(net_type, proto->protocol->channel_mask))
       cf_error("Unsupported channel type");
 
-    if (proto->net_type && (net_type != proto->net_type))
+    if (proto->net_type && (net_type != proto->net_type) && (net_type != NET_MPLS))
       cf_error("Different channel type");
 
     tab = rt_get_default_table(new_config, net_type);
@@ -1502,6 +1503,71 @@ proto_configure_channel(struct proto *p, struct channel **pc, struct channel_con
   return 1;
 }
 
+/**
+ * proto_setup_mpls_map - automatically setup FEC map for protocol
+ * @p: affected protocol
+ * @rts: RTS_* value for generated MPLS routes
+ * @hooks: whether to update rte_insert / rte_remove hooks
+ *
+ * Add, remove or reconfigure MPLS FEC map of the protocol @p, depends on
+ * whether MPLS channel exists, and setup rte_insert / rte_remove hooks with
+ * default MPLS handlers. It is a convenience function supposed to be called
+ * from the protocol start and configure hooks, after reconfiguration of
+ * channels. For shutdown, use proto_shutdown_mpls_map(). If caller uses its own
+ * rte_insert / rte_remove hooks, it is possible to disable updating hooks and
+ * doing that manually.
+ */
+void
+proto_setup_mpls_map(struct proto *p, uint rts)
+{
+  struct mpls_fec_map *m = p->mpls_map;
+  struct channel *c = p->mpls_channel;
+
+  if (!m && c)
+  {
+    /*
+     * Note that when called from a protocol start hook, it is called before
+     * mpls_channel_start(). But FEC map locks MPLS domain internally so it does
+     * not depend on lock from MPLS channel.
+     */
+    p->mpls_map = mpls_fec_map_new(p->pool, c, rts);
+  }
+  else if (m && !c)
+  {
+    /*
+     * Note that for reconfiguration, it is called after the MPLS channel has
+     * been already removed. But removal of active MPLS channel would trigger
+     * protocol restart anyways.
+     */
+    mpls_fec_map_free(m);
+    p->mpls_map = NULL;
+  }
+  else if (m && c)
+  {
+    // mpls_fec_map_reconfigure(m, c);
+  }
+}
+
+
+/**
+ * proto_shutdown_mpls_map - automatically shutdown FEC map for protocol
+ * @p: affected protocol
+ * @hooks: whether to update rte_insert / rte_remove hooks
+ *
+ * Remove MPLS FEC map of the protocol @p during protocol shutdown.
+ */
+void
+proto_shutdown_mpls_map(struct proto *p)
+{
+  struct mpls_fec_map *m = p->mpls_map;
+
+  if (!m)
+    return;
+
+  mpls_fec_map_free(m);
+  p->mpls_map = NULL;
+}
+
 static void
 proto_cleanup(struct proto *p)
 {
@@ -1534,6 +1600,7 @@ proto_loop_stopped(void *ptr)
   proto_cleanup(p);
 }
 
+
 static void
 proto_event(void *ptr)
 {

nest/protocol.h

@@ -34,6 +34,7 @@ struct channel;
 struct ea_list;
 struct eattr;
 struct symbol;
+struct mpls_fec_map;
 
 
 /*
@@ -161,6 +162,8 @@ struct proto {
   struct iface *vrf;			/* Related VRF instance, NULL if global */
   TLIST_LIST(proto_neigh) neighbors;	/* List of neighbor structures */
   struct iface_subscription iface_sub;	/* Interface notification subscription */
+  struct channel *mpls_channel;		/* MPLS channel, when used */
+  struct mpls_fec_map *mpls_map;	/* Maps protocol routes to FECs / labels */
 
   const char *name;			/* Name of this instance (== cf->name) */
   u32 debug;				/* Debugging flags */
@@ -677,12 +680,16 @@ struct channel {
 struct channel_config *proto_cf_find_channel(struct proto_config *p, uint net_type);
 static inline struct channel_config *proto_cf_main_channel(struct proto_config *pc)
 { return proto_cf_find_channel(pc, pc->net_type); }
+static inline struct channel_config *proto_cf_mpls_channel(struct proto_config *pc)
+{ return proto_cf_find_channel(pc, NET_MPLS); }
 
 struct channel *proto_find_channel_by_table(struct proto *p, rtable *t);
 struct channel *proto_find_channel_by_name(struct proto *p, const char *n);
 struct channel *proto_add_channel(struct proto *p, struct channel_config *cf);
 void proto_remove_channel(struct proto *p, struct channel *c);
 int proto_configure_channel(struct proto *p, struct channel **c, struct channel_config *cf);
+void proto_setup_mpls_map(struct proto *p, uint rts);
+void proto_shutdown_mpls_map(struct proto *p);
 
 void channel_set_state(struct channel *c, uint state);
 void channel_schedule_reload(struct channel *c, struct channel_import_request *cir);

nest/route.h

@@ -7,8 +7,8 @@
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
 
-#ifndef _BIRD_NEST_RT_H_
+#ifndef _BIRD_ROUTE_H_
-#define _BIRD_NEST_RT_H_
+#define _BIRD_ROUTE_H_
 
 #include "lib/lists.h"
 #include "lib/bitmap.h"
@@ -161,6 +161,7 @@ struct rtable_private {
   struct tbf rl_pipe;			/* Rate limiting token buffer for pipe collisions */
 
   struct f_trie *flowspec_trie;		/* Trie for evaluation of flowspec notifications */
+  // struct mpls_domain *mpls_domain;	/* Label allocator for MPLS */
 };
 
 /* The final union private-public rtable structure */
@@ -717,6 +718,8 @@ struct hostentry_adata {
   u32 labels[0];
 };
 
+#define HOSTENTRY_LABEL_COUNT(head)	(head->ad.length + sizeof(struct adata) - sizeof(struct hostentry_adata)) / sizeof(u32)
+
 void
 ea_set_hostentry(ea_list **to, rtable *dep, rtable *tab, ip_addr gw, ip_addr ll, u32 lnum, u32 labels[lnum]);
 

nest/rt-attr.c

@@ -1715,6 +1715,11 @@ rta_init(void)
   ea_register_init(&ea_gen_from);
   ea_register_init(&ea_gen_source);
   ea_register_init(&ea_gen_flowspec_valid);
+
+  /* MPLS route attributes */
+  ea_register_init(&ea_gen_mpls_policy);
+  ea_register_init(&ea_gen_mpls_class);
+  ea_register_init(&ea_gen_mpls_label);
 }
 
 /*

nest/rt-show.c

@@ -41,7 +41,7 @@ rt_show_rte(struct cli *c, byte *ia, rte *e, struct rt_show_data *d, int primary
   ea_list *a = e->attrs;
   int sync_error = d->tab->kernel ? krt_get_sync_error(d->tab->kernel, e) : 0;
   void (*get_route_info)(const rte *, byte *buf);
-  eattr *nhea = net_type_match(e->net, NB_DEST) ?
+  const eattr *nhea = net_type_match(e->net, NB_DEST) ?
     ea_find(a, &ea_gen_nexthop) : NULL;
   struct nexthop_adata *nhad = nhea ? (struct nexthop_adata *) nhea->u.ptr : NULL;
   int dest = nhad ? (NEXTHOP_IS_REACHABLE(nhad) ? RTD_UNICAST : nhad->dest) : RTD_NONE;
@@ -67,7 +67,7 @@ rt_show_rte(struct cli *c, byte *ia, rte *e, struct rt_show_data *d, int primary
   if (d->last_table != d->tab)
     rt_show_table(d);
 
-  eattr *heea;
+  const eattr *heea;
   struct hostentry_adata *had = NULL;
   if (!net_is_flow(e->net) && (dest == RTD_NONE) && (heea = ea_find(a, &ea_gen_hostentry)))
     had = (struct hostentry_adata *) heea->u.ptr;
@@ -96,7 +96,7 @@ static void
 rt_show_net(struct rt_show_data *d, const net_addr *n, const rte **feed, uint count)
 {
   struct cli *c = d->cli;
-  byte ia[NET_MAX_TEXT_LENGTH+1];
+  byte ia[NET_MAX_TEXT_LENGTH+16+1];
   struct channel *ec = d->tab->export_channel;
 
   /* The Clang static analyzer complains that ec may be NULL.
@@ -105,6 +105,7 @@ rt_show_net(struct rt_show_data *d, const net_addr *n, const rte **feed, uint co
 
   int first = 1;
   int first_show = 1;
+  uint last_label = 0;
   int pass = 0;
 
   for (uint i = 0; i < count; i++)
@@ -186,13 +187,21 @@ rt_show_net(struct rt_show_data *d, const net_addr *n, const rte **feed, uint co
 
       if (d->stats < 2)
       {
-	if (first_show)
+	uint label = ea_get_int(e.attrs, &ea_gen_mpls_label, ~0U);
-	  net_format(n, ia, sizeof(ia));
+
+	if (first_show || (last_label != label))
+	{
+	  if (!~label)
+	    net_format(n, ia, sizeof(ia));
+	  else
+	    bsnprintf(ia, sizeof(ia), "%N mpls %d", n, label);
+	}
 	else
 	  ia[0] = 0;
 
 	rt_show_rte(c, ia, &e, d, !d->tab->prefilter && !i);
 	first_show = 0;
+	last_label = label;
       }
 
       d->show_counter++;

nest/rt-table.c

@@ -96,6 +96,7 @@
 #include "nest/route.h"
 #include "nest/protocol.h"
 #include "nest/iface.h"
+#include "nest/mpls.h"
 #include "lib/resource.h"
 #include "lib/event.h"
 #include "lib/timer.h"
@@ -1894,21 +1895,22 @@ channel_preimport(struct rt_import_request *req, rte *new, const rte *old)
 
   int new_in = new && !rte_is_filtered(new);
   int old_in = old && !rte_is_filtered(old);
+  
+  int verdict = 1;
 
   if (new_in && !old_in)
     if (CHANNEL_LIMIT_PUSH(c, IN))
       if (c->in_keep & RIK_REJECTED)
-      {
 	new->flags |= REF_FILTERED;
-	return 1;
-      }
       else
-	return 0;
+	verdict = 0;
 
   if (!new_in && old_in)
     CHANNEL_LIMIT_POP(c, IN);
 
-  return 1;
+  mpls_rte_preimport(new_in ? new : NULL, old_in ? old : NULL);
+
+  return verdict;
 }
 
 void
@@ -1951,6 +1953,9 @@ rte_update(struct channel *c, const net_addr *n, rte *new, struct rte_src *src)
 	    new = NULL;
 	}
 
+      if (new && c->proto->mpls_map)
+	mpls_handle_rte(c->proto->mpls_map, n, new);
+
       if (new)
 	if (net_is_flow(n))
 	  rt_flowspec_resolve_rte(new, c);
@@ -1963,7 +1968,6 @@ rte_update(struct channel *c, const net_addr *n, rte *new, struct rte_src *src)
 	  stats->updates_invalid++;
 	  new = NULL;
 	}
-
     }
   else
     stats->withdraws_received++;
@@ -3471,11 +3475,8 @@ rt_postconfig(struct config *c)
 void
 ea_set_hostentry(ea_list **to, rtable *dep, rtable *src, ip_addr gw, ip_addr ll, u32 lnum, u32 labels[lnum])
 {
-  struct {
+  struct hostentry_adata *head = (struct hostentry_adata *) tmp_alloc_adata(
-    struct adata ad;
+      sizeof *head + sizeof(u32) * lnum - sizeof(struct adata));
-    struct hostentry *he;
-    u32 labels[0];
-  } *head = (void *) tmp_alloc_adata(sizeof *head + sizeof(u32) * lnum - sizeof(struct adata));
 
   RT_LOCKED(src, tab)
     head->he = rt_get_hostentry(tab, gw, ll, dep);

sysdep/unix/krt.Y

@@ -33,6 +33,7 @@ CF_KEYWORDS(KERNEL, PERSIST, SCAN, TIME, LEARN, DEVICE, ROUTES, GRACEFUL, RESTAR
 CF_KEYWORDS(INTERFACE, PREFERRED)
 
 %type <i> kern_mp_limit
+%type <cc> kern_channel
 
 CF_GRAMMAR
 
@@ -53,9 +54,15 @@ kern_mp_limit:
  | LIMIT expr  { $$ = $2; if (($2 <= 0) || ($2 > 255)) cf_error("Merge paths limit must be in range 1-255"); }
  ;
 
+
+kern_channel:
+   proto_channel
+ | mpls_channel
+ ;
+
 kern_item:
    proto_item
- | proto_channel { this_proto->net_type = $1->net_type; }
+ | kern_channel { this_proto->net_type = $1->net_type; }
  | PERSIST bool { THIS_KRT->persist = $2; }
  | SCAN TIME expr {
       /* Scan time of 0 means scan on startup only */

sysdep/unix/main.c

@@ -34,6 +34,7 @@
 #include "nest/route.h"
 #include "nest/protocol.h"
 #include "nest/iface.h"
+#include "nest/mpls.h"
 #include "nest/cli.h"
 #include "nest/locks.h"
 #include "conf/conf.h"
@@ -905,6 +906,7 @@ main(int argc, char **argv)
   rt_init();
   io_init();
   if_init();
+  mpls_init();
 //  roa_init();
   config_init();
 

test/bt-utils.c

@@ -16,6 +16,7 @@
 #include "nest/bird.h"
 #include "nest/route.h"
 #include "nest/protocol.h"
+#include "nest/mpls.h"
 
 #include "sysdep/unix/unix.h"
 #include "sysdep/unix/krt.h"
@@ -66,6 +67,7 @@ bt_bird_init(void)
   log_switch(1, NULL, NULL);
   io_init();
   if_init();
+  mpls_init();
   config_init();
 
   protos_build();