diff options
| -rw-r--r-- | doc/bird.sgml | 58 | ||||
| -rw-r--r-- | proto/bgp/bgp.c | 33 | ||||
| -rw-r--r-- | proto/bgp/config.Y | 2 |
3 files changed, 51 insertions, 42 deletions
diff --git a/doc/bird.sgml b/doc/bird.sgml index 421be713..52520a7e 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -1536,33 +1536,37 @@ This allows to set routing policy and all the other parameters differently for each neighbor using the following configuration parameters: <descrip> - <tag>local [<m/ip/] as <m/number/</tag> Define which AS we - are part of. (Note that contrary to other IP routers, BIRD is - able to act as a router located in multiple AS'es - simultaneously, but in such cases you need to tweak the BGP - paths manually in the filters to get consistent behavior.) - Optional <cf/ip/ argument specifies a source address, - equivalent to the <cf/source address/ option (see below). + <tag>local [<m/ip/] as <m/number/</tag> Define which AS we are part + of. (Note that contrary to other IP routers, BIRD is able to act as a + router located in multiple AS'es simultaneously, but in such cases you + need to tweak the BGP paths manually in the filters to get consistent + behavior.) Optional <cf/ip/ argument specifies a source address, + equivalent to the <cf/source address/ option (see below). This + parameter is mandatory. + + <tag>neighbor <m/ip/ as <m/number/</tag> Define neighboring router this + instance will be talking to and what AS it's located in. In case the + neighbor is in the same AS as we are, we automatically switch to iBGP. This parameter is mandatory. - <tag>neighbor <m/ip/ as <m/number/</tag> Define neighboring router - this instance will be talking to and what AS it's located in. Unless - you use the <cf/multihop/ clause, it must be directly connected to one - of your router's interfaces. In case the neighbor is in the same AS - as we are, we automatically switch to iBGP. This parameter is mandatory. - - <tag>multihop [<m/number/]</tag> Configure multihop BGP - session to a neighbor that isn't directly connected. - Accurately, this option should be used if the configured - neighbor IP address does not match with any local network - subnets. Such IP address have to be reachable through system - routing table. For multihop BGP it is recommended to - explicitly configure <cf/source address/ to have it - stable. Optional <cf/number/ argument can be used to specify - the number of hops (used for TTL). Note that the number of - networks (edges) in a path is counted, i.e. if two BGP - speakers are separated by one router, the number of hops is - 2. Default: switched off. + <tag>direct</tag> Specify that the neighbor is directly connected. The + IP address of the neighbor must be from a directly reachable IP range + (i.e. associated with one of your router's interfaces), otherwise the + BGP session wouldn't start but it would wait for such interface to + appear. The alternative is the <cf/multihop/ option. Default: enabled + for eBGP. + + <tag>multihop [<m/number/]</tag> Configure multihop BGP session to a + neighbor that isn't directly connected. Accurately, this option should + be used if the configured neighbor IP address does not match with any + local network subnets. Such IP address have to be reachable through + system routing table. The alternative is the <cf/direct/ option. For + multihop BGP it is recommended to explicitly configure the source + address to have it stable. Optional <cf/number/ argument can be used to + specify the number of hops (used for TTL). Note that the number of + networks (edges) in a path is counted; i.e., if two BGP speakers are + separated by one router, the number of hops is 2. Default: enabled for + iBGP. <tag>source address <m/ip/</tag> Define local address we should use for next hop calculation and as a source address @@ -1609,8 +1613,8 @@ for each neighbor using the following configuration parameters: table, and was used in older versions of BIRD, but does not handle well nontrivial iBGP setups and multihop. Recursive mode is incompatible with <ref id="dsc-sorted" name="sorted - tables">. Default: <cf/direct/ for singlehop eBGP, - <cf/recursive/ otherwise. + tables">. Default: <cf/direct/ for direct sessions, + <cf/recursive/ for multihop sessions. <tag>igp table <m/name/</tag> Specifies a table that is used as an IGP routing table. Default: the same as the table BGP is diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c index cc5318e8..f5b6b8fc 100644 --- a/proto/bgp/bgp.c +++ b/proto/bgp/bgp.c @@ -1006,6 +1006,24 @@ bgp_check_config(struct bgp_config *c) if (c->c.class == SYM_TEMPLATE) return; + + /* EBGP direct by default, IBGP multihop by default */ + if (c->multihop < 0) + c->multihop = internal ? 64 : 0; + + /* Different default for gw_mode */ + if (!c->gw_mode) + c->gw_mode = c->multihop ? GW_RECURSIVE : GW_DIRECT; + + /* Different default based on rs_client */ + if (!c->missing_lladdr) + c->missing_lladdr = c->rs_client ? MLL_IGNORE : MLL_SELF; + + /* Disable after error incompatible with restart limit action */ + if (c->c.in_limit && (c->c.in_limit->action == PLA_RESTART) && c->disable_after_error) + c->c.in_limit->action = PLA_DISABLE; + + if (!c->local_as) cf_error("Local AS number must be set"); @@ -1021,7 +1039,6 @@ bgp_check_config(struct bgp_config *c) if (internal && c->rs_client) cf_error("Only external neighbor can be RS client"); - if (c->multihop && (c->gw_mode == GW_DIRECT)) cf_error("Multihop BGP cannot use direct gateway mode"); @@ -1032,20 +1049,6 @@ bgp_check_config(struct bgp_config *c) if (c->multihop && c->bfd && ipa_zero(c->source_addr)) cf_error("Multihop BGP with BFD requires specified source address"); - - /* Different default based on rs_client */ - if (!c->missing_lladdr) - c->missing_lladdr = c->rs_client ? MLL_IGNORE : MLL_SELF; - - /* Different default for gw_mode */ - if (!c->gw_mode) - c->gw_mode = (c->multihop || internal) ? GW_RECURSIVE : GW_DIRECT; - - /* Disable after error incompatible with restart limit action */ - if (c->c.in_limit && (c->c.in_limit->action == PLA_RESTART) && c->disable_after_error) - c->c.in_limit->action = PLA_DISABLE; - - if ((c->gw_mode == GW_RECURSIVE) && c->c.table->sorted) cf_error("BGP in recursive mode prohibits sorted table"); diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y index 185b1bda..e93501d3 100644 --- a/proto/bgp/config.Y +++ b/proto/bgp/config.Y @@ -34,6 +34,7 @@ CF_ADDTO(proto, bgp_proto '}' { bgp_check_config(BGP_CFG); } ) bgp_proto_start: proto_start BGP { this_proto = proto_config_new(&proto_bgp, sizeof(struct bgp_config), $1); + BGP_CFG->multihop = -1; /* undefined */ BGP_CFG->hold_time = 240; BGP_CFG->connect_retry_time = 120; BGP_CFG->initial_hold_time = 240; @@ -74,6 +75,7 @@ bgp_proto: | bgp_proto STARTUP HOLD TIME expr ';' { BGP_CFG->initial_hold_time = $5; } | bgp_proto CONNECT RETRY TIME expr ';' { BGP_CFG->connect_retry_time = $5; } | bgp_proto KEEPALIVE TIME expr ';' { BGP_CFG->keepalive_time = $4; } + | bgp_proto DIRECT ';' { BGP_CFG->multihop = 0; } | bgp_proto MULTIHOP ';' { BGP_CFG->multihop = 64; } | bgp_proto MULTIHOP expr ';' { BGP_CFG->multihop = $3; if (($3<1) || ($3>255)) cf_error("Multihop must be in range 1-255"); } | bgp_proto NEXT HOP SELF ';' { BGP_CFG->next_hop_self = 1; BGP_CFG->next_hop_keep = 0; } |