bgpd: RFC 5082 Generalized TTL Security Mechanism support
* bgpd: Add support for RFC 5082 GTSM, which allows the TTL field to be used
to verify that incoming packets have been sent from neighbours no more
than X IP hops away. In other words, this allows packets that were sent from
further away (i.e. not by the neighbour with known distance, and so possibly
a miscreant) to be filtered out.
* lib/sockunion.{c,h}: (sockopt_minttl) new function, to set a minimum TTL
using the IP_MINTTL socket opt.
* bgpd.h: (BGP_ERR_NO_EBGP_MULTIHOP_WITH_TTLHACK) define for command
error for minttl.
(struct peer) add a config variable, to store the configured minttl.
(peer_ttl_security_hops_{set,unset}) configuration handlers
* bgpd.c: (peer_group_get) init gtsm_hops
(peer_ebgp_multihop_{un,}set) check for conflicts with GTSM. Multihop and
GTSM can't both be active for a peer at the same time.
(peer_ttl_security_hops_set) set minttl, taking care to avoid conflicts with
ebgp_multihop.
(bgp_config_write_peer) write out minttl as "neighbor .. ttl-security hops X".
* bgp_vty.c: (bgp_vty_return) message for
BGP_ERR_NO_EBGP_MULTIHOP_WITH_TTLHACK
(peer_ebgp_multihop_{un,}set_vty)
* bgp_network.c: (bgp_accept) set minttl on accepted sockets if appropriate.
(bgp_connect) ditto for outbound.
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index a5afaed..39cdf8e 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -303,6 +303,7 @@
/* Peer information */
int fd; /* File descriptor */
int ttl; /* TTL of TCP connection to the peer. */
+ int gtsm_hops; /* minimum hopcount to peer */
char *desc; /* Description of the peer. */
unsigned short port; /* Destination port for peer */
char *host; /* Printable address of the peer. */
@@ -800,7 +801,8 @@
#define BGP_ERR_LOCAL_AS_ALLOWED_ONLY_FOR_EBGP -27
#define BGP_ERR_CANNOT_HAVE_LOCAL_AS_SAME_AS -28
#define BGP_ERR_TCPSIG_FAILED -29
-#define BGP_ERR_MAX -30
+#define BGP_ERR_NO_EBGP_MULTIHOP_WITH_TTLHACK -30
+#define BGP_ERR_MAX -31
extern struct bgp_master *bm;
@@ -953,4 +955,7 @@
extern int peer_clear (struct peer *);
extern int peer_clear_soft (struct peer *, afi_t, safi_t, enum bgp_clear_type);
+extern int peer_ttl_security_hops_set (struct peer *, int);
+extern int peer_ttl_security_hops_unset (struct peer *);
+
#endif /* _QUAGGA_BGPD_H */