Commit 3c360581 authored by Ondřej Zajíček's avatar Ondřej Zajíček

BGP: Mandatory option for channels

Allow to mark channel to be mandatory, and do not allow BGP sessions if
no common AFI/SAFI is established.
parent 7e5f769d
Pipeline #46665 passed with stages
in 5 minutes and 3 seconds
......@@ -2565,6 +2565,15 @@ be used in explicit configuration.
<p>BGP channels have additional config options (together with the common ones):
<descrip>
<tag><label id="bgp-mandatory">mandatory <m/switch/</tag>
When local and neighbor sets of configured AFI/SAFI pairs differ,
capability negotiation ensures that a common subset is used. For
mandatory channels their associated AFI/SAFI must be negotiated
(i.e., also announced by the neighbor), otherwise BGP session
negotiation fails with <it/'Required capability missing'/ error.
Regardless, at least one AFI/SAFI must be negotiated in order to BGP
session be successfully established. Default: off.
<tag><label id="bgp-next-hop-keep">next hop keep <m/switch/|ibgp|ebgp</tag>
Do not modify the Next Hop attribute and advertise the current one
unchanged even in cases where our own local address should be used
......
......@@ -136,6 +136,7 @@ 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 mandatory; /* Channel is mandatory in capability negotiation */
u8 missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
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) */
......
......@@ -29,7 +29,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
SECURITY, DETERMINISTIC, SECONDARY, ALLOW, BFD, ADD, PATHS, RX, TX,
GRACEFUL, RESTART, AWARE, CHECK, LINK, PORT, EXTENDED, MESSAGES, SETKEY,
STRICT, BIND, CONFEDERATION, MEMBER, MULTICAST, FLOW4, FLOW6, LONG,
LIVED, STALE, IMPORT, IBGP, EBGP)
LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY)
%type <i> bgp_nh
%type <i32> bgp_afi
......@@ -223,6 +223,7 @@ 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; }
| MANDATORY bool { BGP_CC->mandatory = $2; }
| MISSING LLADDR SELF { BGP_CC->missing_lladdr = MLL_SELF; }
| MISSING LLADDR DROP { BGP_CC->missing_lladdr = MLL_DROP; }
| MISSING LLADDR IGNORE { BGP_CC->missing_lladdr = MLL_IGNORE; }
......
......@@ -573,6 +573,42 @@ err:
return;
}
static int
bgp_check_capabilities(struct bgp_conn *conn)
{
struct bgp_proto *p = conn->bgp;
struct bgp_caps *local = conn->local_caps;
struct bgp_caps *remote = conn->remote_caps;
struct bgp_channel *c;
int count = 0;
/* This is partially overlapping with bgp_conn_enter_established_state(),
but we need to run this just after we receive OPEN message */
WALK_LIST(c, p->p.channels)
{
const struct bgp_af_caps *loc = bgp_find_af_caps(local, c->afi);
const struct bgp_af_caps *rem = bgp_find_af_caps(remote, c->afi);
/* Find out whether this channel will be active */
int active = loc && loc->ready &&
((rem && rem->ready) || (!remote->length && (c->afi == BGP_AF_IPV4)));
/* Mandatory must be active */
if (c->cf->mandatory && !active)
return 0;
if (active)
count++;
}
/* We need at least one channel active */
if (!count)
return 0;
return 1;
}
static int
bgp_read_options(struct bgp_conn *conn, byte *pos, int len)
{
......@@ -683,6 +719,10 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
if (!id || (p->is_internal && id == p->local_id))
{ bgp_error(conn, 2, 3, pkt+24, -4); return; }
/* RFC 5492 4 - check for required capabilities */
if (p->cf->capabilities && !bgp_check_capabilities(conn))
{ bgp_error(conn, 2, 7, NULL, 0); return; }
struct bgp_caps *caps = conn->remote_caps;
if (caps->as4_support)
......
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