From 631487aa2d45aa2078a08f1852e4a7482abbc2b5 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Thu, 8 Dec 2011 05:53:53 +0100
Subject: Make NEF_STICKY work with fixed interfaces and allow specifying
 interface names

---
 nest/iface.h    |  2 ++
 nest/neighbor.c | 35 ++++++++++++++++++++++++++---------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/nest/iface.h b/nest/iface.h
index 6d333a1..315dda5 100644
--- a/nest/iface.h
+++ b/nest/iface.h
@@ -106,6 +106,7 @@ typedef struct neighbor {
   node if_n;				/* Node in per-interface neighbor list */
   ip_addr addr;				/* Address of the neighbor */
   struct iface *iface;			/* Interface it's connected to */
+  char bound_iface[16];			/* Name of the interface it's bound to */
   struct proto *proto;			/* Protocol this belongs to */
   void *data;				/* Protocol-specific data */
   unsigned aux;				/* Protocol-specific data */
@@ -118,6 +119,7 @@ typedef struct neighbor {
 
 neighbor *neigh_find(struct proto *, ip_addr *, unsigned flags);
 neighbor *neigh_find2(struct proto *p, ip_addr *a, struct iface *ifa, unsigned flags);
+neighbor *neigh_find_ifname(struct proto *, ip_addr *, char *, unsigned flags);
 
 static inline int neigh_connected_to(struct proto *p, ip_addr *a, struct iface *i)
 {
diff --git a/nest/neighbor.c b/nest/neighbor.c
index cf1b2e9..de75b1d 100644
--- a/nest/neighbor.c
+++ b/nest/neighbor.c
@@ -49,6 +49,9 @@
 static slab *neigh_slab;
 static list sticky_neigh_list, neigh_hash_table[NEIGH_HASH_SIZE];
 
+static neighbor *
+neigh_find_internal(struct proto *p, ip_addr *a, struct iface *ifa, char *bound_iface, unsigned flags);
+
 static inline unsigned int
 neigh_hash(struct proto *p, ip_addr *a)
 {
@@ -108,15 +111,26 @@ if_connected(ip_addr *a, struct iface *i) /* -1=error, 1=match, 0=no match */
 neighbor *
 neigh_find(struct proto *p, ip_addr *a, unsigned flags)
 {
-  return neigh_find2(p, a, NULL, flags);
+  return neigh_find_internal(p, a, NULL, NULL, flags);
 }
 
-
 neighbor *
 neigh_find2(struct proto *p, ip_addr *a, struct iface *ifa, unsigned flags)
+{
+  return neigh_find_internal(p, a, ifa, ifa ? ifa->name : NULL, flags);
+}
+
+neighbor *
+neigh_find_ifname(struct proto *p, ip_addr *a, char *ifname, unsigned flags)
+{
+  return neigh_find_internal(p, a, ifname ? if_find_by_name(ifname) : NULL, ifname, flags);
+}
+
+static neighbor *
+neigh_find_internal(struct proto *p, ip_addr *a, struct iface *ifa, char *ifname, unsigned flags)
 {
   neighbor *n;
-  int class, scope = -1;       ;
+  int class, scope = -1;
   unsigned int h = neigh_hash(p, a);
   struct iface *i;
 
@@ -128,7 +142,7 @@ neigh_find2(struct proto *p, ip_addr *a, struct iface *ifa, unsigned flags)
   if (class < 0)			/* Invalid address */
     return NULL;
   if (((class & IADDR_SCOPE_MASK) == SCOPE_HOST) ||
-      (((class & IADDR_SCOPE_MASK) == SCOPE_LINK) && (ifa == NULL)) ||
+      (((class & IADDR_SCOPE_MASK) == SCOPE_LINK) && (ifa == NULL) && (ifname == NULL)) ||
       !(class & IADDR_HOST))
     return NULL;			/* Bad scope or a somecast */
 
@@ -139,7 +153,7 @@ neigh_find2(struct proto *p, ip_addr *a, struct iface *ifa, unsigned flags)
       if ((scope < 0) && (flags & NEF_ONLINK))
 	scope = class & IADDR_SCOPE_MASK;
     }
-  else
+  else if (ifname == NULL)
     WALK_LIST(i, iface_list)
       if ((scope = if_connected(a, i)) >= 0)
 	{
@@ -162,8 +176,6 @@ neigh_find2(struct proto *p, ip_addr *a, struct iface *ifa, unsigned flags)
     }
   else
     {
-      /* sticky flag does not work for link-local neighbors;
-	 fortunately, we don't use this combination */
       add_tail(&sticky_neigh_list, &n->n);
       ifa = NULL;
       scope = -1;
@@ -174,6 +186,8 @@ neigh_find2(struct proto *p, ip_addr *a, struct iface *ifa, unsigned flags)
   n->aux = 0;
   n->flags = flags;
   n->scope = scope;
+  strncpy(n->bound_iface, ifname ?: "", sizeof(n->bound_iface)-1);
+
   return n;
 }
 
@@ -195,6 +209,8 @@ neigh_dump(neighbor *n)
   debug("%s %p %08x scope %s", n->proto->name, n->data, n->aux, ip_scope_text(n->scope));
   if (n->flags & NEF_STICKY)
     debug(" STICKY");
+  if (*n->bound_iface)
+    debug(" bound to %s", n->bound_iface);
   debug("\n");
 }
 
@@ -230,7 +246,7 @@ neigh_dump_all(void)
  * addresses belonging to prefixes of the interface belonging to @ifa
  * and causes all unreachable neighbors to be flushed
  *
- * A change of the scope of a neighbor is handle as a remove with
+ * A change of the scope of a neighbor is handled as a remove with
  * a consequent add
  */
 void
@@ -262,7 +278,8 @@ neigh_ifa_update(struct ifa *a)
 
   /* Traverse the sticky neighbor list to find neighbors that are reachable now */
   WALK_LIST_DELSAFE(n, next, sticky_neigh_list)
-    if ((scope = if_connected(&n->addr, i)) >= 0)
+    if ((!(*n->bound_iface) || strcmp(n->bound_iface, i->name) == 0)
+	&& (scope = if_connected(&n->addr, i)) >= 0)
       {
 	n->iface = i;
 	n->scope = scope;
-- 
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