BGP: Support for routes with mixed-AF next hops

Covers IPv4/VPNv4 routes with IPv6 next hop (RFC 5549), IPv6 routes with
IPv4 next hop (RFC 4798) and VPNv6 routes with IPv4 next hop (RFC 4659).
Unfortunately it also makes next hop hooks more messy.

Each BGP channel now could have two IGP tables, one for IPv4 next hops,
the other for IPv6 next hops.

1 files changed, 14 insertions, 3 deletions

diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 36fd39e8..6511680d 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -61,7 +61,8 @@ struct bgp_bucket;
 struct bgp_af_desc {
   u32 afi;
   u32 net;
-  int mpls;
+  u8 mpls;
+  u8 no_igp;
   const char *name;
   uint (*encode_nlri)(struct bgp_write_state *s, struct bgp_bucket *buck, byte *buf, uint size);
   void (*decode_nlri)(struct bgp_parse_state *s, byte *pos, uint len, rta *a);
@@ -122,6 +123,7 @@ struct bgp_channel_config {
   struct channel_config c;
 
   u32 afi;
+  const struct bgp_af_desc *desc;
 
   ip_addr next_hop_addr;		/* Local address for NEXT_HOP attribute */
   u8 next_hop_self;			/* Always set next hop to local IP address */
@@ -133,7 +135,9 @@ struct bgp_channel_config {
   u8 ext_next_hop;			/* Allow both IPv4 and IPv6 next hops */
   u8 add_path;				/* Use ADD-PATH extension [RFC 7911] */
 
-  struct rtable_config *igp_table;	/* Table used for recursive next hop lookups */
+  uint rest[0];				/* Remaining items are reconfigured separately */
+  struct rtable_config *igp_table_ip4;	/* Table for recursive IPv4 next hop lookups */
+  struct rtable_config *igp_table_ip6;	/* Table for recursive IPv6 next hop lookups */
 };
 
 #define MLL_SELF 1
@@ -274,7 +278,8 @@ struct bgp_channel {
   HASH(struct bgp_prefix) prefix_hash;	/* Prefixes to be sent */
   slab *prefix_slab;			/* Slab holding prefix nodes */
 
-  rtable *igp_table;			/* Table used for recursive next hop lookups */
+  rtable *igp_table_ip4;		/* Table for recursive IPv4 next hop lookups */
+  rtable *igp_table_ip6;		/* Table for recursive IPv6 next hop lookups */
   ip_addr next_hop_addr;		/* Local address for NEXT_HOP attribute */
   ip_addr link_addr;			/* Link-local version of next_hop_addr */
 
@@ -393,6 +398,12 @@ static inline int bgp_channel_is_ipv4(struct bgp_channel *c)
 static inline int bgp_channel_is_ipv6(struct bgp_channel *c)
 { return BGP_AFI(c->afi) == BGP_AFI_IPV6; }
 
+static inline int bgp_cc_is_ipv4(struct bgp_channel_config *c)
+{ return BGP_AFI(c->afi) == BGP_AFI_IPV4; }
+
+static inline int bgp_cc_is_ipv6(struct bgp_channel_config *c)
+{ return BGP_AFI(c->afi) == BGP_AFI_IPV6; }
+
 static inline uint bgp_max_packet_length(struct bgp_conn *conn)
 { return conn->ext_messages ? BGP_MAX_EXT_MSG_LENGTH : BGP_MAX_MESSAGE_LENGTH; }