From 470740f97bfa61c3c5c79d6f2d92f2014a119031 Mon Sep 17 00:00:00 2001
From: "Ondrej Zajicek (work)" <santiago@crfreenet.org>
Date: Wed, 2 Jan 2019 16:01:21 +0100
Subject: [PATCH] BGP: Better dispatch of incoming connections

Since v2 we have multiple listening BGP sockets, and each BGP protocol
has associated one of them. Use listening socket that accepted the
incoming connection as a key in the dispatch process so only BGP
protocols assocaited with that listening socket can be selected.
This is necesary for proper dispatch when VRFs are used.
---
 proto/bgp/bgp.c  | 18 ++++++++++++------
 sysdep/unix/io.c |  1 +
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index ceeec727..43f9f134 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -188,6 +188,7 @@ bgp_open(struct bgp_proto *p)
   bs->sk = sk;
   bs->uc = 1;
   p->sock = bs;
+  sk->data = bs;
 
   add_tail(&bgp_sockets, &bs->n);
 
@@ -1049,7 +1050,8 @@ bgp_connect(struct bgp_proto *p)	/* Enter Connect state and start establishing c
   s->tos = IP_PREC_INTERNET_CONTROL;
   s->password = p->cf->password;
   s->tx_hook = bgp_connected;
-  BGP_TRACE(D_EVENTS, "Connecting to %I%J from local address %I%J", s->daddr, p->cf->iface,
+  BGP_TRACE(D_EVENTS, "Connecting to %I%J from local address %I%J",
+	    s->daddr, ipa_is_link_local(s->daddr) ? p->cf->iface : NULL,
 	    s->saddr, ipa_is_link_local(s->saddr) ? s->iface : NULL);
   bgp_setup_conn(p, conn);
   bgp_setup_sk(conn, s);
@@ -1083,12 +1085,15 @@ bgp_find_proto(sock *sk)
 {
   struct bgp_proto *p;
 
+  /* sk->iface is valid only if src or dst address is link-local */
+  int link = ipa_is_link_local(sk->saddr) || ipa_is_link_local(sk->daddr);
+
   WALK_LIST(p, proto_list)
     if ((p->p.proto == &proto_bgp) &&
+	(p->sock == sk->data) &&
 	ipa_equal(p->cf->remote_ip, sk->daddr) &&
-	(!p->cf->iface  || (p->cf->iface == sk->iface)) &&
-	(ipa_zero(p->cf->local_ip) || ipa_equal(p->cf->local_ip, sk->saddr)) &&
-	(p->cf->local_port == sk->sport))
+	(!link || (p->cf->iface == sk->iface)) &&
+	(ipa_zero(p->cf->local_ip) || ipa_equal(p->cf->local_ip, sk->saddr)))
       return p;
 
   return NULL;
@@ -1765,8 +1770,9 @@ bgp_postconfig(struct proto_config *CF)
   if (!cf->remote_as)
     cf_error("Remote AS number must be set");
 
-  if (ipa_is_link_local(cf->remote_ip) && !cf->iface)
-    cf_error("Link-local neighbor address requires specified interface");
+  if (!cf->iface && (ipa_is_link_local(cf->local_ip) ||
+		     ipa_is_link_local(cf->remote_ip)))
+    cf_error("Link-local addresses require defined interface");
 
   if (!(cf->capabilities && cf->enable_as4) && (cf->remote_as > 0xFFFF))
     cf_error("Neighbor AS number out of range (AS4 not available)");
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index a511e88e..d1d86e3b 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -1077,6 +1077,7 @@ sk_passive_connected(sock *s, int type)
 
   sock *t = sk_new(s->pool);
   t->type = type;
+  t->data = s->data;
   t->af = s->af;
   t->fd = fd;
   t->ttl = s->ttl;