Merge commit '8f79e6b9' into thread-next

6 files changed, 32 insertions, 5 deletions

diff --git a/doc/bird.sgml b/doc/bird.sgml
index 0cfe19c4..8c882ee6 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -2938,6 +2938,20 @@ be used in explicit configuration.
 	BGP session (if acceptable), or the preferred address of an associated
 	interface.
 
+	<tag><label id="bgp-next-hop-prefer">next hop prefer global</tag>
+	Prefer global IPv6 address to link-local IPv6 address for immediate next
+	hops of received routes. For IPv6 routes, the Next Hop attribute may
+	contain both a global IP address and a link-local IP address. For IBGP
+	sessions, the global IP address is resolved (<ref id="bgp-gateway"
+	name="gateway recursive">) through an IGP routing table
+	(<ref id="bgp-igp-table" name="igp table">) to get an immediate next
+	hop. If the resulting IGP route is a direct route (i.e., the next hop is
+	a direct neighbor), then the link-local IP address from the Next Hop
+	attribute is used as the immediate next hop. This option change it to
+	use the global IP address instead. Note that even with this option
+	enabled a route may end with a link-local immediate next hop when the
+	IGP route has one. Default: disabled.
+
 	<tag><label id="bgp-gateway">gateway direct|recursive</tag>
 	For received routes, their <cf/gw/ (immediate next hop) attribute is
 	computed from received <cf/bgp_next_hop/ attribute. This option
diff --git a/nest/rt-table.c b/nest/rt-table.c
index 8980f147..f4ca9170 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -4740,6 +4740,7 @@ rt_update_hostcache(void *data)
 static struct hostentry *
 rt_get_hostentry(struct rtable_private *tab, ip_addr a, ip_addr ll, rtable *dep)
 {
+  ip_addr link = ipa_zero(ll) ? a : ll;
   struct hostentry *he;
 
   if (!tab->hostcache)
@@ -4748,10 +4749,10 @@ rt_get_hostentry(struct rtable_private *tab, ip_addr a, ip_addr ll, rtable *dep)
   u32 k = hc_hash(a, dep);
   struct hostcache *hc = tab->hostcache;
   for (he = hc->hash_table[k >> hc->hash_shift]; he != NULL; he = he->next)
-    if (ipa_equal(he->addr, a) && (he->tab == dep))
+    if (ipa_equal(he->addr, a) && ipa_equal(he->link, link) && (he->tab == dep))
       return he;
 
-  he = hc_new_hostentry(hc, tab->rp, a, ipa_zero(ll) ? a : ll, dep, k);
+  he = hc_new_hostentry(hc, tab->rp, a, link, dep, k);
   rt_update_hostentry(tab, he);
   return he;
 }
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index f8655d47..2f8da1af 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -2105,6 +2105,10 @@ bgp_postconfig(struct proto_config *CF)
     if (!cc->gw_mode)
       cc->gw_mode = cf->multihop ? GW_RECURSIVE : GW_DIRECT;
 
+    /* Different default for next_hop_prefer */
+    if (!cc->next_hop_prefer)
+      cc->next_hop_prefer = (cc->gw_mode == GW_DIRECT) ? NHP_GLOBAL : NHP_LOCAL;
+
     /* Defaults based on proto config */
     if (cc->gr_able == 0xff)
       cc->gr_able = (cf->gr_mode == BGP_GR_ABLE);
@@ -2235,6 +2239,7 @@ bgp_channel_reconfigure(struct channel *C, struct channel_config *CC, int *impor
     return 0;
 
   if ((new->gw_mode != old->gw_mode) ||
+      (new->next_hop_prefer != old->next_hop_prefer) ||
       (new->aigp != old->aigp) ||
       (new->cost != old->cost))
   {
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index c7b8e40b..b87e0fc4 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -145,6 +145,7 @@ struct bgp_channel_config {
   ip_addr next_hop_addr;		/* Local address for NEXT_HOP attribute */
   u8 next_hop_self;			/* Always set next hop to local IP address (NH_*) */
   u8 next_hop_keep;			/* Do not modify next hop attribute (NH_*) */
+  u8 next_hop_prefer;			/* Prefer global or link-local next hop (NHP_*) */
   u8 mandatory;				/* Channel is mandatory in capability negotiation */
   u8 gw_mode;				/* How we compute route gateway from next_hop attr, see GW_* */
   u8 secondary;				/* Accept also non-best routes (i.e. RA_ACCEPTED) */
@@ -187,6 +188,9 @@ struct bgp_channel_config {
 #define GW_DIRECT		1
 #define GW_RECURSIVE		2
 
+#define NHP_GLOBAL		1
+#define NHP_LOCAL		2
+
 #define BGP_ADD_PATH_RX		1
 #define BGP_ADD_PATH_TX		2
 #define BGP_ADD_PATH_FULL	3
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 9f0d2306..b4edf2c5 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -31,7 +31,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
 	LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL, SETS,
 	DYNAMIC, RANGE, NAME, DIGITS, AIGP, ORIGINATE, COST, ENFORCE,
 	FIRST, FREE, VALIDATE, BASE, ROLE, ROLES, PEER, PROVIDER, CUSTOMER,
-	RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC)
+	RS_SERVER, RS_CLIENT, REQUIRE, BGP_OTC, PREFER, GLOBAL)
 
 %type <i> bgp_nh
 %type <i32> bgp_afi
@@ -264,6 +264,7 @@ bgp_channel_item:
  | NEXT HOP ADDRESS ipa { BGP_CC->next_hop_addr = $4; }
  | NEXT HOP SELF bgp_nh { BGP_CC->next_hop_self = $4; }
  | NEXT HOP KEEP bgp_nh { BGP_CC->next_hop_keep = $4; }
+ | NEXT HOP PREFER GLOBAL { BGP_CC->next_hop_prefer = NHP_GLOBAL; }
  | MANDATORY bool { BGP_CC->mandatory = $2; }
  | MISSING LLADDR bgp_lladdr { log(L_WARN "%s.%s: Missing lladdr option is deprecated and ignored, remove it", this_proto->name, this_channel->name); }
  | GATEWAY DIRECT { BGP_CC->gw_mode = GW_DIRECT; }
diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
index f9c1da41..506268c9 100644
--- a/proto/bgp/packets.c
+++ b/proto/bgp/packets.c
@@ -1028,13 +1028,15 @@ bgp_apply_next_hop(struct bgp_parse_state *s, ea_list **to, ip_addr gw, ip_addr
       WITHDRAW(BAD_NEXT_HOP " - zero address");
 
     rtable *tab = ipa_is_ip4(gw) ? c->igp_table_ip4 : c->igp_table_ip6;
+    ip_addr lla = (c->cf->next_hop_prefer == NHP_LOCAL) ? ll : IPA_NONE;
+
     if (s->mpls)
     {
       u32 labels[BGP_MPLS_MAX];
-      ea_set_hostentry(to, c->c.table, tab, gw, ll, BGP_MPLS_MAX, labels);
+      ea_set_hostentry(to, c->c.table, tab, gw, lla, BGP_MPLS_MAX, labels);
     }
     else
-      ea_set_hostentry(to, c->c.table, tab, gw, ll, 0, NULL);
+      ea_set_hostentry(to, c->c.table, tab, gw, lla, 0, NULL);
   }
 }