From 8b258e4e659cd8bacf0f7e3997d30b43561ac3e6 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Fri, 21 Apr 2000 13:01:28 +0000
Subject: LOCAL_PREF is now always present and exported over all ibgp
 connections [draft]

Allow setting of address of the local end of the TCP connection.

Several bug fixes.
---
 proto/bgp/attrs.c  | 31 ++++++++++++++++++++++++-------
 proto/bgp/bgp.c    |  5 ++++-
 proto/bgp/bgp.h    |  1 +
 proto/bgp/config.Y |  3 ++-
 4 files changed, 31 insertions(+), 9 deletions(-)

(limited to 'proto/bgp')

diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index f7d7b78..1a75884 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -6,9 +6,6 @@
  *	Can be freely distributed and used under the terms of the GNU GPL.
  */
 
-/* FIXME: Latest draft says that LOCAL_PREF is mandatory for iBGP */
-/* FIXME: Mandatory attributes may be missing in messages that don't contain NLRI */
-
 #define LOCAL_DEBUG
 
 #include <stdlib.h>
@@ -352,7 +349,7 @@ bgp_get_bucket(struct bgp_proto *p, ea_list *old, ea_list *tmp, int originate)
   new = alloca(ea_scan(tmp));
   ea_merge(tmp, new);
   t->next = NULL;
-  ea_sort(tmp);
+  ea_sort(new);
 
   /* Normalize attributes */
   d = new->attrs;
@@ -470,14 +467,14 @@ bgp_rt_notify(struct proto *P, net *n, rte *new, rte *old, ea_list *tmpa)
 static int
 bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *pool)
 {
-  ea_list *ea = lp_alloc(pool, sizeof(ea_list) + 3*sizeof(eattr));
+  ea_list *ea = lp_alloc(pool, sizeof(ea_list) + 4*sizeof(eattr));
   eattr *a = ea->attrs;
   rta *rta = e->attrs;
 
   ea->next = *attrs;
   *attrs = ea;
   ea->flags = EALF_SORTED;
-  ea->count = 3;
+  ea->count = 4;
 
   a->id = EA_CODE(EAP_BGP, BA_ORIGIN);
   a->flags = BAF_TRANSITIVE;
@@ -502,7 +499,7 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
       a->u.ptr = lp_alloc(pool, sizeof(struct adata) + 4);
       a->u.ptr->length = 4;
       z = a->u.ptr->data;
-      z[0] = 2;				/* AS_SEQUENCE */
+      z[0] = AS_PATH_SEQUENCE;
       z[1] = 1;				/* 1 AS */
       put_u16(z+2, p->local_as);
     }
@@ -519,6 +516,12 @@ bgp_create_attrs(struct bgp_proto *p, rte *e, ea_list **attrs, struct linpool *p
     *(ip_addr *)a->u.ptr->data = p->local_addr;
   else
     *(ip_addr *)a->u.ptr->data = e->attrs->gw;
+  a++;
+
+  a->id = EA_CODE(EAP_BGP, BA_LOCAL_PREF);
+  a->flags = BAF_OPTIONAL;
+  a->type = EAF_TYPE_INT;
+  a->u.data = 0;
 
   return 0;				/* Leave decision to the filters */
 }
@@ -822,6 +825,20 @@ bgp_decode_attrs(struct bgp_conn *conn, byte *attr, unsigned int len, struct lin
       return NULL;
     }
 
+  /* If there's no local preference, define one */
+  if (!(seen[0] && (1 << BA_LOCAL_PREF)))
+    {
+      ea = lp_alloc(pool, sizeof(ea_list) + sizeof(eattr));
+      ea->next = a->eattrs;
+      a->eattrs = ea;
+      ea->flags = 0;
+      ea->count = 1;
+      ea->attrs[0].id = EA_CODE(EAP_BGP, BA_LOCAL_PREF);
+      ea->attrs[0].flags = BAF_OPTIONAL;
+      ea->attrs[0].type = EAF_TYPE_INT;
+      ea->attrs[0].u.data = 0;
+    }
+
   /* Fill in the remaining rta fields */
   e = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
   ASSERT(e);
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 933ced8..27ade8e 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -210,7 +210,10 @@ bgp_connect(struct bgp_proto *p)	/* Enter Connect state and start establishing c
   DBG("BGP: Connecting\n");
   s = sk_new(p->p.pool);
   s->type = SK_TCP_ACTIVE;
-  s->saddr = p->local_addr;
+  if (ipa_nonzero(p->cf->source_addr))
+    s->saddr = p->cf->source_addr;
+  else
+    s->saddr = p->local_addr;
   s->daddr = p->cf->remote_ip;
   s->dport = BGP_PORT;
   bgp_setup_sk(p, conn, s);
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index b8e1abc..2e22111 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -20,6 +20,7 @@ struct bgp_config {
   ip_addr remote_ip;
   int multihop;				/* Number of hops if multihop */
   ip_addr multihop_via;			/* Multihop: address to route to */
+  ip_addr source_addr;			/* Source address to use */
   int next_hop_self;			/* Always set next hop to local IP address */
   int compare_path_lengths;		/* Use path lengths when selecting best route */
   u32 default_local_pref;		/* Default value for LOCAL_PREF attribute */
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 37f90aa..36356c5 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -17,7 +17,7 @@ CF_DECLS
 CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	MULTIHOP, STARTUP, VIA, NEXT, HOP, SELF, DEFAULT, PATH, METRIC,
 	BGP_PATH, BGP_LOCAL_PREF, BGP_MED, BGP_ORIGIN, BGP_NEXT_HOP,
-	BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY)
+	BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS)
 
 CF_GRAMMAR
 
@@ -55,6 +55,7 @@ bgp_proto:
  | bgp_proto PATH METRIC NUM ';' { BGP_CFG->compare_path_lengths = $4; }
  | bgp_proto DEFAULT BGP_MED NUM ';' { BGP_CFG->default_med = $4; }
  | bgp_proto DEFAULT BGP_LOCAL_PREF NUM ';' { BGP_CFG->default_local_pref = $4; }
+ | bgp_proto SOURCE ADDRESS IPA ';' { BGP_CFG->source_addr = $4; }
  ;
 
 CF_ADDTO(dynamic_attr, BGP_PATH
-- 
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