Merge master into int-new

5 files changed, 32 insertions, 20 deletions

diff --git a/doc/bird.sgml b/doc/bird.sgml
index 4bbcb871..01b59c6a 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -2047,8 +2047,9 @@ using the following configuration parameters:
 	<tag><label id="bgp-iface">interface <m/string/</tag>
 	Define interface we should use for link-local BGP IPv6 sessions.
 	Interface can also be specified as a part of <cf/neighbor address/
-	(e.g., <cf/neighbor fe80::1234%eth0 as 65000;/). It is an error to use
-	this parameter for non link-local sessions.
+	(e.g., <cf/neighbor fe80::1234%eth0 as 65000;/). The option may also be
+	used for non link-local sessions when it is necessary to explicitly
+	specify an interface, but only for direct (not multihop) sessions.
 
 	<tag><label id="bgp-direct">direct</tag>
 	Specify that the neighbor is directly connected. The IP address of the
@@ -2232,6 +2233,14 @@ using the following configuration parameters:
 	TX direction. When active, all available routes accepted by the export
 	filter are advertised to the neighbor. Default: off.
 
+	<tag><label id="bgp-allow-local-pref">allow bgp_local_pref <m/switch/</tag>
+	A standard BGP implementation do not send the Local Preference attribute
+	to eBGP neighbors and ignore this attribute if received from eBGP
+	neighbors, as per <rfc id="4271">.  When this option is enabled on an
+	eBGP session, this attribute will be sent to and accepted from the peer,
+	which is useful for example if you have a setup like in <rfc id="7938">.
+	The option does not affect iBGP sessions. Default: off.
+
 	<tag><label id="bgp-allow-local-as">allow local as [<m/number/]</tag>
 	BGP prevents routing loops by rejecting received routes with the local
 	AS number in the AS path. This option allows to loose or disable the
@@ -3991,16 +4000,17 @@ protocol rip [ng] [&lt;name&gt;] {
 
 <p><code>
 protocol rip {
-        debug all;
-        port 1520;
-        period 12;
-        garbage time 60;
-        interface "eth0" { metric 3; mode multicast; };
-        interface "eth*" { metric 2; mode broadcast; };
-        authentication cryptographic;
-        password "secret-shared-key" { algorithm hmac sha256; };
-        import filter { print "importing"; accept; };
-        export filter { print "exporting"; accept; };
+	import all;
+	export all;
+	interface "eth*" {
+		metric 2;
+		port 1520;
+		mode multicast;
+		update time 12;
+		timeout time 60;
+		authentication cryptographic;
+		password "secret" { algorithm hmac sha256; };
+	};
 }
 </code>
 
diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c
index cf9db1c8..882ba44e 100644
--- a/proto/bgp/attrs.c
+++ b/proto/bgp/attrs.c
@@ -358,14 +358,14 @@ bgp_decode_med(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *da
 static void
 bgp_export_local_pref(struct bgp_export_state *s, eattr *a)
 {
-  if (!s->proto->is_interior)
+  if (!s->proto->is_interior && !s->proto->cf->allow_local_pref)
     UNSET(a);
 }
 
 static void
 bgp_decode_local_pref(struct bgp_parse_state *s, uint code UNUSED, uint flags, byte *data, uint len, ea_list **to)
 {
-  if (!s->proto->is_interior)
+  if (!s->proto->is_interior && !s->proto->cf->allow_local_pref)
     DISCARD(BAD_EBGP, "LOCAL_PREF");
 
   if (len != 4)
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 86f7be1b..b9a1d157 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -979,7 +979,7 @@ bgp_find_proto(sock *sk)
   WALK_LIST(p, proto_list)
     if ((p->p.proto == &proto_bgp) &&
 	ipa_equal(p->cf->remote_ip, sk->daddr) &&
-	(!ipa_is_link_local(sk->daddr) || (p->cf->iface == sk->iface)) &&
+	(!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))
       return p;
@@ -1608,11 +1608,8 @@ bgp_postconfig(struct proto_config *CF)
   if (!cf->remote_as)
     cf_error("Remote AS number must be set");
 
-  // if (ipa_is_link_local(c->remote_ip) && !c->iface)
-  //   cf_error("Link-local neighbor address requires specified interface");
-
-  if (!ipa_is_link_local(cf->remote_ip) != !cf->iface)
-    cf_error("Link-local address and interface scope must be used together");
+  if (ipa_is_link_local(cf->remote_ip) && !cf->iface)
+    cf_error("Link-local neighbor address requires specified interface");
 
   if (!(cf->capabilities && cf->enable_as4) && (cf->remote_as > 0xFFFF))
     cf_error("Neighbor AS number out of range (AS4 not available)");
@@ -1630,6 +1627,9 @@ bgp_postconfig(struct proto_config *CF)
 		       ipa_is_link_local(cf->remote_ip)))
     cf_error("Multihop BGP cannot be used with link-local addresses");
 
+  if (cf->multihop && cf->iface)
+    cf_error("Multihop BGP cannot be bound to interface");
+
   if (cf->multihop && cf->check_link)
     cf_error("Multihop BGP cannot depend on link state");
 
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 61d3600d..7ffcb68a 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -105,6 +105,7 @@ struct bgp_config {
   int passive;				/* Do not initiate outgoing connection */
   int interpret_communities;		/* Hardwired handling of well-known communities */
   int allow_local_as;			/* Allow that number of local ASNs in incoming AS_PATHs */
+  int allow_local_pref;			/* Allow LOCAL_PREF in EBGP sessions */
   int gr_mode;				/* Graceful restart mode (BGP_GR_*) */
   int setkey;				/* Set MD5 password to system SA/SP database */
   unsigned gr_time;			/* Graceful restart timeout */
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 63e82285..941ae5b6 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -126,6 +126,7 @@ bgp_proto:
  | bgp_proto INTERPRET COMMUNITIES bool ';' { BGP_CFG->interpret_communities = $4; }
  | bgp_proto ALLOW LOCAL AS ';' { BGP_CFG->allow_local_as = -1; }
  | bgp_proto ALLOW LOCAL AS expr ';' { BGP_CFG->allow_local_as = $5; }
+ | bgp_proto ALLOW BGP_LOCAL_PREF bool ';' { BGP_CFG->allow_local_pref = $4; }
  | bgp_proto GRACEFUL RESTART bool ';' { BGP_CFG->gr_mode = $4; }
  | bgp_proto GRACEFUL RESTART AWARE ';' { BGP_CFG->gr_mode = BGP_GR_AWARE; }
  | bgp_proto GRACEFUL RESTART TIME expr ';' { BGP_CFG->gr_time = $5; }