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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.
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@ -2565,6 +2565,15 @@ be used in explicit configuration.
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<p>BGP channels have additional config options (together with the common ones):
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<descrip>
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<tag><label id="bgp-mandatory">mandatory <m/switch/</tag>
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When local and neighbor sets of configured AFI/SAFI pairs differ,
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capability negotiation ensures that a common subset is used. For
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mandatory channels their associated AFI/SAFI must be negotiated
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(i.e., also announced by the neighbor), otherwise BGP session
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negotiation fails with <it/'Required capability missing'/ error.
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Regardless, at least one AFI/SAFI must be negotiated in order to BGP
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session be successfully established. Default: off.
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<tag><label id="bgp-next-hop-keep">next hop keep <m/switch/|ibgp|ebgp</tag>
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Do not modify the Next Hop attribute and advertise the current one
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unchanged even in cases where our own local address should be used
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@ -136,6 +136,7 @@ struct bgp_channel_config {
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ip_addr next_hop_addr; /* Local address for NEXT_HOP attribute */
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u8 next_hop_self; /* Always set next hop to local IP address (NH_*) */
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u8 next_hop_keep; /* Do not modify next hop attribute (NH_*) */
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u8 mandatory; /* Channel is mandatory in capability negotiation */
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u8 missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
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u8 gw_mode; /* How we compute route gateway from next_hop attr, see GW_* */
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u8 secondary; /* Accept also non-best routes (i.e. RA_ACCEPTED) */
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@ -29,7 +29,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
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SECURITY, DETERMINISTIC, SECONDARY, ALLOW, BFD, ADD, PATHS, RX, TX,
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GRACEFUL, RESTART, AWARE, CHECK, LINK, PORT, EXTENDED, MESSAGES, SETKEY,
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STRICT, BIND, CONFEDERATION, MEMBER, MULTICAST, FLOW4, FLOW6, LONG,
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LIVED, STALE, IMPORT, IBGP, EBGP)
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LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY)
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%type <i> bgp_nh
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%type <i32> bgp_afi
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@ -223,6 +223,7 @@ bgp_channel_item:
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| NEXT HOP ADDRESS ipa { BGP_CC->next_hop_addr = $4; }
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| NEXT HOP SELF bgp_nh { BGP_CC->next_hop_self = $4; }
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| NEXT HOP KEEP bgp_nh { BGP_CC->next_hop_keep = $4; }
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| MANDATORY bool { BGP_CC->mandatory = $2; }
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| MISSING LLADDR SELF { BGP_CC->missing_lladdr = MLL_SELF; }
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| MISSING LLADDR DROP { BGP_CC->missing_lladdr = MLL_DROP; }
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| MISSING LLADDR IGNORE { BGP_CC->missing_lladdr = MLL_IGNORE; }
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@ -573,6 +573,42 @@ err:
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return;
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}
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static int
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bgp_check_capabilities(struct bgp_conn *conn)
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{
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struct bgp_proto *p = conn->bgp;
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struct bgp_caps *local = conn->local_caps;
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struct bgp_caps *remote = conn->remote_caps;
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struct bgp_channel *c;
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int count = 0;
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/* This is partially overlapping with bgp_conn_enter_established_state(),
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but we need to run this just after we receive OPEN message */
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WALK_LIST(c, p->p.channels)
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{
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const struct bgp_af_caps *loc = bgp_find_af_caps(local, c->afi);
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const struct bgp_af_caps *rem = bgp_find_af_caps(remote, c->afi);
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/* Find out whether this channel will be active */
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int active = loc && loc->ready &&
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((rem && rem->ready) || (!remote->length && (c->afi == BGP_AF_IPV4)));
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/* Mandatory must be active */
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if (c->cf->mandatory && !active)
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return 0;
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if (active)
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count++;
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}
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/* We need at least one channel active */
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if (!count)
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return 0;
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return 1;
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}
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static int
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bgp_read_options(struct bgp_conn *conn, byte *pos, int len)
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{
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@ -683,6 +719,10 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
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if (!id || (p->is_internal && id == p->local_id))
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{ bgp_error(conn, 2, 3, pkt+24, -4); return; }
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/* RFC 5492 4 - check for required capabilities */
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if (p->cf->capabilities && !bgp_check_capabilities(conn))
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{ bgp_error(conn, 2, 7, NULL, 0); return; }
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struct bgp_caps *caps = conn->remote_caps;
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if (caps->as4_support)
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