BGP: Allow exchanging LOCAL_PREF with eBGP peers (1950a479) · Commits · 戴 / Bird

doc/bird.sgml

+8 −0

Original line number	Diff line number	Diff line
		@@ -2043,6 +2043,14 @@ using the following configuration parameters:
		TX direction. When active, all available routes accepted by the export
		filter are advertised to the neighbor. Default: off.

		<tag><label id="bgp-allow-local-pref">allow bgp_local_pref <m/switch/</tag>
		A standard BGP implementation do not send the Local Preference attribute
		to eBGP neighbors and ignore this attribute if received from eBGP
		neighbors, as per <rfc id="4271">. When this option is enabled on an
		eBGP session, this attribute will be sent to and accepted from the peer,
		which is useful for example if you have a setup like in <rfc id="7938">.
		The option does not affect iBGP sessions. Default: off.

		<tag><label id="bgp-allow-local-as">allow local as [<m/number/]</tag>
		BGP prevents routing loops by rejecting received routes with the local
		AS number in the AS path. This option allows to loose or disable the

+15 −5

Original line number	Diff line number	Diff line
		@@ -306,7 +306,7 @@ static struct attr_desc bgp_attr_table[] = {
		bgp_check_next_hop, bgp_format_next_hop },
		{ "med", 4, BAF_OPTIONAL, EAF_TYPE_INT, 1, /* BA_MULTI_EXIT_DISC */
		NULL, NULL },
		{ "local_pref", 4, BAF_TRANSITIVE, EAF_TYPE_INT, 0, /* BA_LOCAL_PREF */
		{ "local_pref", 4, BAF_TRANSITIVE, EAF_TYPE_INT, 1, /* BA_LOCAL_PREF */
		NULL, NULL },
		{ "atomic_aggr", 0, BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_ATOMIC_AGGR */
		NULL, NULL },
		@@ -821,8 +821,13 @@ bgp_get_bucket(struct bgp_proto p, net n, ea_list *attrs, int originate)
		code = EA_ID(a->id);
		if (ATTR_KNOWN(code))
		{
		if (!bgp_attr_table[code].allow_in_ebgp && !p->is_internal)
		if (!p->is_internal)
		{
		if (!bgp_attr_table[code].allow_in_ebgp)
		continue;
		if ((code == BA_LOCAL_PREF) && !p->cf->allow_local_pref)
		continue;
		}
		/* The flags might have been zero if the attr was added by filters */
		a->flags = (a->flags & BAF_PARTIAL) \| bgp_attr_table[code].expected_flags;
		if (code < 32)
		@@ -1776,8 +1781,13 @@ bgp_decode_attrs(struct bgp_conn conn, byte attr, uint len, struct linpool *po
		{ errcode = 5; goto err; }
		if ((desc->expected_flags ^ flags) & (BAF_OPTIONAL \| BAF_TRANSITIVE))
		{ errcode = 4; goto err; }
		if (!desc->allow_in_ebgp && !bgp->is_internal)
		if (!bgp->is_internal)
		{
		if (!desc->allow_in_ebgp)
		continue;
		if ((code == BA_LOCAL_PREF) && !bgp->cf->allow_local_pref)
		continue;
		}
		if (desc->validate)
		{
		errcode = desc->validate(bgp, z, l);

+1 −0

Original line number	Diff line number	Diff line
		@@ -50,6 +50,7 @@ struct bgp_config {
		int secondary; /* Accept also non-best routes (i.e. RA_ACCEPTED) */
		int add_path; /* Use ADD-PATH extension [RFC7911] */
		int allow_local_as; /* Allow that number of local ASNs in incoming AS_PATHs */
		int allow_local_pref; /* Allow LOCAL_PREF in EBGP sessions */
		int gr_mode; /* Graceful restart mode (BGP_GR_) /
		int setkey; /* Set MD5 password to system SA/SP database */
		unsigned gr_time; /* Graceful restart timeout */

+1 −0

Original line number	Diff line number	Diff line
		@@ -126,6 +126,7 @@ bgp_proto:
		\| bgp_proto ADD PATHS RX ';' { BGP_CFG->add_path = ADD_PATH_RX; }
		\| bgp_proto ADD PATHS TX ';' { BGP_CFG->add_path = ADD_PATH_TX; }
		\| bgp_proto ADD PATHS bool ';' { BGP_CFG->add_path = $4 ? ADD_PATH_FULL : 0; }
		\| bgp_proto ALLOW BGP_LOCAL_PREF bool ';' { BGP_CFG->allow_local_pref = $4; }
		\| bgp_proto ALLOW LOCAL AS ';' { BGP_CFG->allow_local_as = -1; }
		\| bgp_proto ALLOW LOCAL AS expr ';' { BGP_CFG->allow_local_as = $5; }
		\| bgp_proto GRACEFUL RESTART bool ';' { BGP_CFG->gr_mode = $4; }