BGP: Promiscuous ASN mode (23ee6b1c) · Commits · 戴 / Bird

doc/bird.sgml

+7 −4

Original line number	Diff line number	Diff line
		@@ -2195,12 +2195,15 @@ using the following configuration parameters:
		<cf/local 10.0.0.1; local as 65000;/ are valid). This parameter is
		mandatory.

		<tag><label id="bgp-neighbor">neighbor [<m/ip/] [port <m/number/] [as <m/number/]</tag>
		<tag><label id="bgp-neighbor">neighbor [<m/ip/] [port <m/number/] [as <m/number/] [internal\|external]</tag>
		Define neighboring router this instance will be talking to and what AS
		it is located in. In case the neighbor is in the same AS as we are, we
		automatically switch to iBGP. Optionally, the remote port may also be
		specified. Like <cf/local/ parameter, this parameter may also be used
		multiple times with different sub-options. This parameter is mandatory.
		automatically switch to IBGP. Alternatively, it is possible to specify
		just <cf/internal/ or </cf/external/ instead of AS number, in that case
		either local AS number, or any external AS number is accepted.
		Optionally, the remote port may also be specified. Like <cf/local/
		parameter, this parameter may also be used multiple times with different
		sub-options. This parameter is mandatory.

		<tag><label id="bgp-iface">interface <m/string/</tag>
		Define interface we should use for link-local BGP IPv6 sessions.

proto/bgp/bgp.c

+20 −5

Original line number	Diff line number	Diff line
		@@ -507,6 +507,10 @@ bgp_conn_enter_established_state(struct bgp_conn *conn)
		if (ipa_zero(p->local_ip))
		p->local_ip = conn->sk->saddr;

		/* For promiscuous sessions */
		if (!p->remote_as)
		p->remote_as = conn->received_as;

		/* In case of LLv6 is not valid during BGP start */
		if (ipa_zero(p->link_addr) && p->neigh && p->neigh->iface && p->neigh->iface->llv6)
		p->link_addr = p->neigh->iface->llv6->ip;
		@@ -1754,14 +1758,19 @@ void
		bgp_postconfig(struct proto_config *CF)
		{
		struct bgp_config cf = (void ) CF;
		int internal = (cf->local_as == cf->remote_as);
		int interior = internal \|\| cf->confederation_member;

		/* Do not check templates at all */
		if (cf->c.class == SYM_TEMPLATE)
		return;


		/* Handle undefined remote_as, zero should mean unspecified external */
		if (!cf->remote_as && (cf->peer_type == BGP_PT_INTERNAL))
		cf->remote_as = cf->local_as;

		int internal = (cf->local_as == cf->remote_as);
		int interior = internal \|\| cf->confederation_member;

		/* EBGP direct by default, IBGP multihop by default */
		if (cf->multihop < 0)
		cf->multihop = internal ? 64 : 0;
		@@ -1781,8 +1790,14 @@ bgp_postconfig(struct proto_config *CF)
		if (ipa_zero(cf->remote_ip))
		cf_error("Neighbor must be configured");

		if (!cf->remote_as)
		cf_error("Remote AS number must be set");
		if (!cf->remote_as && !cf->peer_type)
		cf_error("Remote AS number (or peer type) must be set");

		if ((cf->peer_type == BGP_PT_INTERNAL) && !internal)
		cf_error("IBGP cannot have different ASNs");

		if ((cf->peer_type == BGP_PT_EXTERNAL) && internal)
		cf_error("EBGP cannot have the same ASNs");

		if (!cf->iface && (ipa_is_link_local(cf->local_ip) \|\|
		ipa_is_link_local(cf->remote_ip)))
		@@ -2242,7 +2257,7 @@ bgp_show_proto_info(struct proto *P)

		cli_msg(-1006, " BGP state: %s", bgp_state_dsc(p));
		cli_msg(-1006, " Neighbor address: %I%J", p->cf->remote_ip, p->cf->iface);
		cli_msg(-1006, " Neighbor AS: %u", p->cf->remote_as);
		cli_msg(-1006, " Neighbor AS: %u", p->cf->remote_as ?: p->remote_as);

		if (p->gr_active_num)
		cli_msg(-1006, " Neighbor graceful restart active");

proto/bgp/bgp.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -83,6 +83,7 @@ struct bgp_config {
		struct iface iface; / Interface for link-local addresses */
		u16 local_port; /* Local listening port */
		u16 remote_port; /* Neighbor destination port */
		int peer_type; /* Internal or external BGP (BGP_PT_, optional) /
		int multihop; /* Number of hops if multihop */
		int strict_bind; /* Bind listening socket to local address */
		int ttl_security; /* Enable TTL security [RFC 5082] */
		@@ -152,6 +153,9 @@ struct bgp_channel_config {
		struct rtable_config igp_table_ip6; / Table for recursive IPv6 next hop lookups */
		};

		#define BGP_PT_INTERNAL 1
		#define BGP_PT_EXTERNAL 2

		#define NH_NO 0
		#define NH_ALL 1
		#define NH_IBGP 2
		@@ -237,6 +241,7 @@ struct bgp_conn {
		u8 state; /* State of connection state machine */
		u8 as4_session; /* Session uses 4B AS numbers in AS_PATH (both sides support it) */
		u8 ext_messages; /* Session uses extended message length */
		u32 received_as; /* ASN received in OPEN message */

		struct bgp_caps *local_caps;
		struct bgp_caps *remote_caps;

proto/bgp/config.Y

+3 −1

Original line number	Diff line number	Diff line
		@@ -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, MANDATORY)
		LIVED, STALE, IMPORT, IBGP, EBGP, MANDATORY, INTERNAL, EXTERNAL)

		%type <i> bgp_nh
		%type <i32> bgp_afi
		@@ -82,6 +82,8 @@ bgp_nbr_opts:
		/* empty */
		\| bgp_nbr_opts PORT expr { BGP_CFG->remote_port = $3; if (($3<1) \|\| ($3>65535)) cf_error("Invalid port number"); }
		\| bgp_nbr_opts AS expr { BGP_CFG->remote_as = $3; }
		\| bgp_nbr_opts INTERNAL { BGP_CFG->peer_type = BGP_PT_INTERNAL; }
		\| bgp_nbr_opts EXTERNAL { BGP_CFG->peer_type = BGP_PT_EXTERNAL; }
		;

		bgp_cease_mask:

proto/bgp/packets.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -732,13 +732,18 @@ bgp_rx_open(struct bgp_conn conn, byte pkt, uint len)
		if ((as4 != asn) && (asn != AS_TRANS))
		log(L_WARN "%s: Peer advertised inconsistent AS numbers", p->p.name);

		if (as4 != p->remote_as)
		/* When remote ASN is unspecified, it must be external one */
		if (p->remote_as ? (as4 != p->remote_as) : (as4 == p->local_as))
		{ as4 = htonl(as4); bgp_error(conn, 2, 2, (byte *) &as4, 4); return; }

		conn->received_as = as4;
		}
		else
		{
		if (asn != p->remote_as)
		if (p->remote_as ? (asn != p->remote_as) : (asn == p->local_as))
		{ bgp_error(conn, 2, 2, pkt+20, 2); return; }

		conn->received_as = asn;
		}

		/* Check the other connection */

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