BGP: Handle case where capabilites are not used

If peer does not announce capabilities at all, or when we have
capabilities disabled, handle that as implicit IPv4 unicast.
This commit is contained in:
Ondrej Zajicek (work) 2019-03-15 20:54:01 +01:00
parent 5d511948cd
commit 7e5f769d91
3 changed files with 14 additions and 0 deletions

View file

@ -491,6 +491,7 @@ bgp_conn_enter_openconfirm_state(struct bgp_conn *conn)
}
static const struct bgp_af_caps dummy_af_caps = { };
static const struct bgp_af_caps basic_af_caps = { .ready = 1 };
void
bgp_conn_enter_established_state(struct bgp_conn *conn)
@ -541,6 +542,13 @@ bgp_conn_enter_established_state(struct bgp_conn *conn)
const struct bgp_af_caps *loc = bgp_find_af_caps(local, c->afi);
const struct bgp_af_caps *rem = bgp_find_af_caps(peer, c->afi);
/* Use default if capabilities were not announced */
if (!local->length && (c->afi == BGP_AF_IPV4))
loc = &basic_af_caps;
if (!peer->length && (c->afi == BGP_AF_IPV4))
rem = &basic_af_caps;
/* Ignore AFIs that were not announced in multiprotocol capability */
if (!loc || !loc->ready)
loc = &dummy_af_caps;

View file

@ -215,6 +215,7 @@ struct bgp_caps {
u8 llgr_aware; /* Long-lived GR capability, RFC draft */
u16 af_count; /* Number of af_data items */
u16 length; /* Length of capabilities in OPEN msg */
struct bgp_af_caps af_data[0]; /* Per-AF capability data */
};

View file

@ -217,6 +217,7 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf)
struct bgp_af_caps *ac;
uint any_ext_next_hop = 0;
uint any_add_path = 0;
byte *buf_head = buf;
byte *data;
/* Prepare bgp_caps structure */
@ -394,6 +395,8 @@ bgp_write_capabilities(struct bgp_conn *conn, byte *buf)
data[-1] = buf - data;
}
caps->length = buf - buf_head;
return buf;
}
@ -405,6 +408,8 @@ bgp_read_capabilities(struct bgp_conn *conn, struct bgp_caps *caps, byte *pos, i
int i, cl;
u32 af;
caps->length += len;
while (len > 0)
{
if (len < 2 || len < (2 + pos[1]))