Neighbors: Locking and asynchronous notifications

nest/iface.c

@@ -36,10 +36,12 @@
 
 static pool *if_pool;
 
+DOMAIN(attrs) iface_domain;
 list global_iface_list;
 struct iface default_vrf;
 
 static void if_recalc_preferred(struct iface *i);
+static void ifa_delete_locked(struct ifa *a);
 
 /**
  * ifa_dump - dump interface address
@@ -50,6 +52,7 @@ static void if_recalc_preferred(struct iface *i);
 void
 ifa_dump(struct ifa *a)
 {
+  IFACE_LEGACY_ACCESS;
   debug("\t%I, net %N bc %I -> %I%s%s%s%s\n", a->ip, &a->prefix, a->brd, a->opposite,
 	(a->flags & IA_PRIMARY) ? " PRIMARY" : "",
 	(a->flags & IA_SECONDARY) ? " SEC" : "",
@@ -69,6 +72,7 @@ if_dump(struct iface *i)
 {
   struct ifa *a;
 
+  IFACE_LEGACY_ACCESS;
   debug("IF%d: %s", i->index, i->name);
   if (i->flags & IF_SHUTDOWN)
     debug(" SHUTDOWN");
@@ -110,6 +114,7 @@ if_dump_all(void)
 {
   struct iface *i;
 
+  IFACE_LEGACY_ACCESS;
   debug("Known network interfaces:\n");
   WALK_LIST(i, global_iface_list)
     if_dump(i);
@@ -307,6 +312,9 @@ if_update(struct iface *new)
   if (!new->master)
     new->master = &default_vrf;
 
+  IFACE_LEGACY_ACCESS;
+  IFACE_LOCK;
+
   WALK_LIST(i, global_iface_list)
     if (!strcmp(new->name, i->name))
       {
@@ -328,6 +336,8 @@ if_update(struct iface *new)
 	  }
 
 	if_copy(i, new);
+	IFACE_UNLOCK;
+
 	if (c)
 	  if_notify_change(c, i);
 
@@ -341,6 +351,8 @@ newif:
   init_list(&i->neighbors);
   i->flags |= IF_UPDATED | IF_TMP_DOWN;		/* Tmp down as we don't have addresses yet */
   add_tail(&global_iface_list, &i->n);
+  IFACE_UNLOCK;
+
   return i;
 }
 
@@ -350,6 +362,7 @@ if_start_update(void)
   struct iface *i;
   struct ifa *a;
 
+  IFACE_LEGACY_ACCESS;
   WALK_LIST(i, global_iface_list)
     {
       i->flags &= ~IF_UPDATED;
@@ -361,6 +374,8 @@ if_start_update(void)
 void
 if_end_partial_update(struct iface *i)
 {
+  IFACE_LEGACY_ACCESS;
+
   if (i->flags & IF_NEEDS_RECALC)
     if_recalc_preferred(i);
 
@@ -374,6 +389,7 @@ if_end_update(void)
   struct iface *i;
   struct ifa *a, *b;
 
+  IFACE_LEGACY_ACCESS;
   WALK_LIST(i, global_iface_list)
     {
       if (!(i->flags & IF_UPDATED))
@@ -382,7 +398,11 @@ if_end_update(void)
 	{
 	  WALK_LIST_DELSAFE(a, b, i->addrs)
 	    if (!(a->flags & IA_UPDATED))
-	      ifa_delete(a);
+	    {
+	      IFACE_LOCK;
+	      ifa_delete_locked(a);
+	      IFACE_UNLOCK;
+	    }
 	  if_end_partial_update(i);
 	}
     }
@@ -391,6 +411,7 @@ if_end_update(void)
 void
 if_flush_ifaces(struct proto *p)
 {
+  IFACE_LEGACY_ACCESS;
   if (p->debug & D_EVENTS)
     log(L_TRACE "%s: Flushing interfaces", p->name);
   if_start_update();
@@ -410,6 +431,8 @@ if_feed_baby(struct proto *p)
   struct iface *i;
   struct ifa *a;
 
+  IFACE_LEGACY_ACCESS;
+
   if (!p->if_notify && !p->ifa_notify)	/* shortcut */
     return;
   DBG("Announcing interfaces to new protocol %s\n", p->name);
@@ -435,9 +458,15 @@ if_find_by_index(unsigned idx)
 {
   struct iface *i;
 
+  IFACE_LOCK;
   WALK_LIST(i, global_iface_list)
     if (i->index == idx && !(i->flags & IF_SHUTDOWN))
+    {
+      IFACE_UNLOCK;
       return i;
+    }
+
+  IFACE_UNLOCK;
   return NULL;
 }
 
@@ -454,9 +483,15 @@ if_find_by_name(const char *name)
 {
   struct iface *i;
 
+  IFACE_LOCK;
   WALK_LIST(i, global_iface_list)
     if (!strcmp(i->name, name) && !(i->flags & IF_SHUTDOWN))
+    {
+      IFACE_UNLOCK;
       return i;
+    }
+
+  IFACE_UNLOCK;
   return NULL;
 }
 
@@ -465,17 +500,21 @@ if_get_by_name(const char *name)
 {
   struct iface *i;
 
+  IFACE_LEGACY_ACCESS;
+
   WALK_LIST(i, global_iface_list)
     if (!strcmp(i->name, name))
       return i;
 
   /* No active iface, create a dummy */
+  IFACE_LOCK;
   i = mb_allocz(if_pool, sizeof(struct iface));
   strncpy(i->name, name, sizeof(i->name)-1);
   i->flags = IF_SHUTDOWN;
   init_list(&i->addrs);
   init_list(&i->neighbors);
   add_tail(&global_iface_list, &i->n);
+  IFACE_UNLOCK;
   return i;
 }
 
@@ -561,6 +600,8 @@ if_recalc_all_preferred_addresses(void)
 {
   struct iface *i;
 
+  IFACE_LEGACY_ACCESS;
+
   WALK_LIST(i, global_iface_list)
   {
     if_recalc_preferred(i);
@@ -591,6 +632,8 @@ ifa_update(struct ifa *a)
   struct iface *i = a->iface;
   struct ifa *b;
 
+  IFACE_LEGACY_ACCESS;
+
   WALK_LIST(b, i->addrs)
     if (ifa_same(b, a))
       {
@@ -609,10 +652,12 @@ ifa_update(struct ifa *a)
   if ((a->prefix.type == NET_IP4) && (i->flags & IF_BROADCAST) && ipa_zero(a->brd))
     log(L_WARN "Missing broadcast address for interface %s", i->name);
 
+  IFACE_LOCK;
   b = mb_alloc(if_pool, sizeof(struct ifa));
   memcpy(b, a, sizeof(struct ifa));
   add_tail(&i->addrs, &b->n);
   b->flags |= IA_UPDATED;
+  IFACE_UNLOCK;
 
   i->flags |= IF_NEEDS_RECALC;
   if (i->flags & IF_UP)
@@ -637,6 +682,17 @@ ifa_delete(struct ifa *a)
   WALK_LIST(b, i->addrs)
     if (ifa_same(b, a))
       {
+	IFACE_LOCK;
+	ifa_delete_locked(b);
+	IFACE_UNLOCK;
+	return;
+      }
+}
+
+static void
+ifa_delete_locked(struct ifa *b)
+{
+	struct iface *i = b->iface;
 	rem_node(&b->n);
 
 	if (b->flags & IA_PRIMARY)
@@ -659,7 +715,6 @@ ifa_delete(struct ifa *a)
 
 	mb_free(b);
 	return;
-      }
 }
 
 u32
@@ -668,6 +723,8 @@ if_choose_router_id(struct iface_patt *mask, u32 old_id)
   struct iface *i;
   struct ifa *a, *b;
 
+  IFACE_LEGACY_ACCESS;
+
   b = NULL;
   WALK_LIST(i, global_iface_list)
     {
@@ -715,6 +772,7 @@ if_choose_router_id(struct iface_patt *mask, u32 old_id)
 void
 if_init(void)
 {
+  iface_domain = DOMAIN_NEW(attrs, "Interfaces");
   if_pool = rp_new(&root_pool, &main_birdloop, "Interfaces");
   init_list(&global_iface_list);
   strcpy(default_vrf.name, "default");
@@ -844,6 +902,8 @@ if_show(void)
   struct ifa *a;
   char *type;
 
+  IFACE_LEGACY_ACCESS;
+
   WALK_LIST(i, global_iface_list)
     {
       if (i->flags & IF_SHUTDOWN)
@@ -886,6 +946,8 @@ if_show_summary(void)
 {
   struct iface *i;
 
+  IFACE_LEGACY_ACCESS;
+
   cli_msg(-2005, "%-10s %-6s %-18s %s", "Interface", "State", "IPv4 address", "IPv6 address");
   WALK_LIST(i, global_iface_list)
     {

nest/iface.h

@@ -9,10 +9,20 @@
 #ifndef _BIRD_IFACE_H_
 #define _BIRD_IFACE_H_
 
+#include "lib/event.h"
 #include "lib/lists.h"
 #include "lib/ip.h"
+#include "lib/locking.h"
 
+DEFINE_DOMAIN(attrs);
 extern list global_iface_list;
+extern DOMAIN(attrs) iface_domain;
+
+#define IFACE_LEGACY_ACCESS	ASSERT_DIE(birdloop_inside(&main_birdloop))
+
+#define IFACE_LOCK	  LOCK_DOMAIN(attrs, iface_domain)
+#define IFACE_UNLOCK	UNLOCK_DOMAIN(attrs, iface_domain)
+#define ASSERT_IFACE_LOCKED	ASSERT_DIE(DOMAIN_IS_LOCKED(attrs, iface_domain))
 
 struct proto;
 struct pool;
@@ -131,6 +141,7 @@ typedef struct neighbor {
   struct ifa *ifa;			/* Ifa on related iface */
   struct iface *iface;			/* Interface it's connected to */
   struct iface *ifreq;			/* Requested iface, NULL for any */
+  struct event event;			/* Notification event */
   struct proto *proto;			/* Protocol this belongs to */
   void *data;				/* Protocol-specific data */
   uint aux;				/* Protocol-specific data */

nest/neighbor.c

@@ -59,6 +59,7 @@
 
 static slab *neigh_slab;
 static list neigh_hash_table[NEIGH_HASH_SIZE], sticky_neigh_list;
+static void neigh_do_notify(void *);
 
 static inline uint
 neigh_hash(struct proto *p, ip_addr a, struct iface *i)
@@ -210,36 +211,40 @@ if_intersect(struct iface *ia, struct iface *ib)
 neighbor *
 neigh_find(struct proto *p, ip_addr a, struct iface *iface, uint flags)
 {
-  ASSERT_DIE(birdloop_inside(&main_birdloop));
-
   neighbor *n;
   int class, scope = -1;
   uint h = neigh_hash(p, a, iface);
   struct iface *ifreq = iface;
   struct ifa *addr = NULL;
 
+  IFACE_LOCK;
   WALK_LIST(n, neigh_hash_table[h])	/* Search the cache */
     if ((n->proto == p) && ipa_equal(n->addr, a) && (n->ifreq == iface))
+    {
+      IFACE_UNLOCK;
       return n;
+    }
+
+#define NOT_FOUND goto not_found
 
   if (flags & NEF_IFACE)
   {
     if (ipa_nonzero(a) || !iface)
-      return NULL;
+      NOT_FOUND;
   }
   else
   {
     class = ipa_classify(a);
     if (class < 0)			/* Invalid address */
-      return NULL;
+      NOT_FOUND;
     if (((class & IADDR_SCOPE_MASK) == SCOPE_HOST) ||
 	(((class & IADDR_SCOPE_MASK) == SCOPE_LINK) && !iface) ||
 	!(class & IADDR_HOST))
-      return NULL;			/* Bad scope or a somecast */
+      NOT_FOUND;			/* Bad scope or a somecast */
   }
 
   if ((flags & NEF_ONLINK) && !iface)
-      return NULL;
+    NOT_FOUND;
 
   if (iface)
   {
@@ -253,7 +258,7 @@ neigh_find(struct proto *p, ip_addr a, struct iface *iface, uint flags)
   /* scope >= 0  <=>  iface != NULL */
 
   if ((scope < 0) && !(flags & NEF_STICKY))
-    return NULL;
+    NOT_FOUND;
 
   n = sl_allocz(neigh_slab);
   add_tail(&neigh_hash_table[h], &n->n);
@@ -265,8 +270,23 @@ neigh_find(struct proto *p, ip_addr a, struct iface *iface, uint flags)
   n->proto = p;
   n->flags = flags;
   n->scope = scope;
+  n->event = (event) { .hook = neigh_do_notify, .data = n };
+  ASSERT_DIE(birdloop_inside(p->loop));
 
+  if (p->loop == &main_birdloop)
+    n->event.list = &global_event_list;
+  else
+  {
+    birdloop_link(p->loop);
+    n->event.list = birdloop_event_list(p->loop);
+  }
+
+  IFACE_UNLOCK;
   return n;
+
+not_found:
+  IFACE_UNLOCK;
+  return NULL;
 }
 
 /**
@@ -300,11 +320,15 @@ neigh_dump_all(void)
   neighbor *n;
   int i;
 
+  IFACE_LOCK;
+
   debug("Known neighbors:\n");
   for(i=0; i<NEIGH_HASH_SIZE; i++)
     WALK_LIST(n, neigh_hash_table[i])
       neigh_dump(n);
   debug("\n");
+
+  IFACE_UNLOCK;
 }
 
 static inline void
@@ -313,7 +337,16 @@ neigh_notify(neighbor *n)
   if (!n->proto->neigh_notify)
     return;
 
-  PROTO_LOCKED_FROM_MAIN(n->proto)
+  ev_send(n->event.list, &n->event);
+}
+
+static void
+neigh_do_notify(void *data)
+{
+  neighbor *n = data;
+
+  ASSERT_DIE(birdloop_inside(n->proto->loop));
+
   if (n->proto->proto_state != PS_STOP)
     n->proto->neigh_notify(n);
 }
@@ -351,6 +384,8 @@ neigh_free(neighbor *n)
 {
   rem_node(&n->n);
   rem_node(&n->if_n);
+  ev_postpone(&n->event);
+  birdloop_unlink(n->proto->loop);
   sl_free(neigh_slab, n);
 }
 
@@ -366,6 +401,8 @@ neigh_free(neighbor *n)
 void
 neigh_update(neighbor *n, struct iface *iface)
 {
+  ASSERT_IFACE_LOCKED;
+
   struct proto *p = n->proto;
   struct ifa *ifa = NULL;
   int scope = -1;
@@ -439,6 +476,8 @@ neigh_if_up(struct iface *i)
   neighbor *n;
   node *x, *y;
 
+  IFACE_LOCK;
+
   /* Update neighbors that might be better off with the new iface */
   WALK_LIST(ii, global_iface_list)
     if (!EMPTY_LIST(ii->neighbors) && (ii != i) && if_intersect(i, ii))
@@ -447,6 +486,8 @@ neigh_if_up(struct iface *i)
 
   WALK_LIST2_DELSAFE(n, x, y, sticky_neigh_list, if_n)
     neigh_update(n, i);
+
+  IFACE_UNLOCK;
 }
 
 /**
@@ -463,8 +504,12 @@ neigh_if_down(struct iface *i)
   neighbor *n;
   node *x, *y;
 
+  IFACE_LOCK;
+
   WALK_LIST2_DELSAFE(n, x, y, i->neighbors, if_n)
     neigh_update(n, i);
+
+  IFACE_UNLOCK;
 }
 
 /**
@@ -480,8 +525,12 @@ neigh_if_link(struct iface *i)
   neighbor *n;
   node *x, *y;
 
+  IFACE_LOCK;
+
   WALK_LIST2_DELSAFE(n, x, y, i->neighbors, if_n)
     neigh_notify(n);
+
+  IFACE_UNLOCK;
 }
 
 /**
@@ -501,6 +550,8 @@ neigh_ifa_up(struct ifa *a)
   neighbor *n;
   node *x, *y;
 
+  IFACE_LOCK;
+
   /* Update neighbors that might be better off with the new ifa */
   WALK_LIST(ii, global_iface_list)
     if (!EMPTY_LIST(ii->neighbors) && ifa_intersect(a, ii))
@@ -510,6 +561,8 @@ neigh_ifa_up(struct ifa *a)
   /* Wake up all sticky neighbors that are reachable now */
   WALK_LIST2_DELSAFE(n, x, y, sticky_neigh_list, if_n)
     neigh_update(n, i);
+
+  IFACE_UNLOCK;
 }
 
 void
@@ -519,10 +572,14 @@ neigh_ifa_down(struct ifa *a)
   neighbor *n;
   node *x, *y;
 
+  IFACE_LOCK;
+
   /* Update all neighbors whose scope has changed */
   WALK_LIST2_DELSAFE(n, x, y, i->neighbors, if_n)
     if (n->ifa == a)
       neigh_update(n, i);
+
+  IFACE_UNLOCK;
 }
 
 static inline void
@@ -548,10 +605,14 @@ neigh_prune(void)
   node *m;
   int i;
 
+  IFACE_LOCK;
+
   DBG("Pruning neighbors\n");
   for(i=0; i<NEIGH_HASH_SIZE; i++)
     WALK_LIST_DELSAFE(n, m, neigh_hash_table[i])
       neigh_prune_one(n);
+
+  IFACE_UNLOCK;
 }
 
 /**

nest/rt-attr.c

@@ -86,7 +86,6 @@ const char * rta_dest_names[RTD_MAX] = {
   [RTD_PROHIBIT]	= "prohibited",
 };
 
-DEFINE_DOMAIN(attrs);
 static DOMAIN(attrs) src_domain;
 
 #define SRC_LOCK	LOCK_DOMAIN(attrs, src_domain)

proto/babel/babel.c

@@ -1907,6 +1907,7 @@ babel_reconfigure_ifaces(struct babel_proto *p, struct babel_config *cf)
 {
   struct iface *iface;
 
+  IFACE_LEGACY_ACCESS;
   WALK_LIST(iface, global_iface_list)
   {
     if (!(iface->flags & IF_UP))

proto/ospf/iface.c

@@ -1225,6 +1225,7 @@ ospf_reconfigure_ifaces2(struct ospf_proto *p)
   struct iface *iface;
   struct ifa *a;
 
+  IFACE_LEGACY_ACCESS;
   WALK_LIST(iface, global_iface_list)
   {
     if (! (iface->flags & IF_UP))
@@ -1271,6 +1272,7 @@ ospf_reconfigure_ifaces3(struct ospf_proto *p)
   struct iface *iface;
   struct ifa *a;
 
+  IFACE_LEGACY_ACCESS;
   WALK_LIST(iface, global_iface_list)
   {
     if (! (iface->flags & IF_UP))

proto/radv/radv.c

@@ -663,6 +663,7 @@ radv_reconfigure(struct proto *P, struct proto_config *CF)
   if (!old->propagate_routes && new->propagate_routes)
     channel_request_feeding(p->p.main_channel);
 
+  IFACE_LEGACY_ACCESS;
   struct iface *iface;
   WALK_LIST(iface, global_iface_list)
   {

proto/rip/rip.c

@@ -776,6 +776,7 @@ rip_reconfigure_ifaces(struct rip_proto *p, struct rip_config *cf)
 {
   struct iface *iface;
 
+  IFACE_LEGACY_ACCESS;
   WALK_LIST(iface, global_iface_list)
   {
     if (!(iface->flags & IF_UP))

sysdep/bsd/krt-sock.c

@@ -242,6 +242,7 @@ krt_send_route(struct krt_proto *p, int cmd, const rte *e)
    */
   if (!i)
   {
+    IFACE_LOCK;
     WALK_LIST(j, global_iface_list)
     {
       if (j->flags & IF_LOOPBACK)
@@ -250,6 +251,7 @@ krt_send_route(struct krt_proto *p, int cmd, const rte *e)
         break;
       }
     }
+    IFACE_UNLOCK;
 
     if (!i)
     {

sysdep/linux/netlink.c

@@ -1147,6 +1147,7 @@ kif_do_scan(struct kif_proto *p UNUSED)
       log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);
 
   /* Re-resolve master interface for slaves */
+  IFACE_LEGACY_ACCESS;
   struct iface *i;
   WALK_LIST(i, global_iface_list)
     if (i->master_index)