BGP: Minor cleanups (82f42ea0) · Commits · 戴 / Bird

doc/bird.sgml

+11 −8

Original line number	Diff line number	Diff line
		@@ -2040,6 +2040,16 @@ using the following configuration parameters:
		source address for the BGP session. Default: the address of the local
		end of the interface our neighbor is connected to.

		<tag><label id="bgp-strict-bind">strict bind <m/switch/</tag>
		Specify whether BGP listening socket should be bound to a specific local
		address (the same as the <cf/source address/) and associated interface,
		or to all addresses. Binding to a specific address could be useful in
		cases like running multiple BIRD instances on a machine, each using its
		IP address. Note that listening sockets bound to a specific address and
		to all addresses collide, therefore either all BGP protocols (of the
		same address family and using the same local port) should have set
		<cf/strict bind/, or none of them. Default: disabled.

		<tag><label id="bgp-next-hop-self">next hop self</tag>
		Avoid calculation of the Next Hop attribute and always advertise our own
		source address as a next hop. This needs to be used only occasionally to
		@@ -2112,7 +2122,7 @@ using the following configuration parameters:
		Note that full (ICMP protection, for example) <rfc id="5082"> support is
		provided by Linux only. Default: disabled.

		<tag><label id="bgp-pass">password <m/string/</tag>
		<tag><label id="bgp-password">password <m/string/</tag>
		Use this password for MD5 authentication of BGP sessions (<rfc id="2385">). When
		used on BSD systems, see also <cf/setkey/ option below. Default: no
		authentication.
		@@ -2270,13 +2280,6 @@ using the following configuration parameters:
		This option is relevant to IPv4 mode with enabled capability
		advertisement only. Default: on.

		<tag><label id="bgp-route-limit">route limit <m/number/</tag>
		The maximal number of routes that may be imported from the protocol. If
		the route limit is exceeded, the connection is closed with an error.
		Limit is currently implemented as <cf>import limit <m/number/ action
		restart</cf>. This option is obsolete and it is replaced by
		<ref id="proto-import-limit" name="import limit option">. Default: no limit.

		<tag><label id="bgp-disable-after-error">disable after error <m/switch/</tag>
		When an error is encountered (either locally or by the other side),
		disable the instance automatically and wait for an administrator to fix

proto/bgp/attrs.c

+27 −20

Original line number	Diff line number	Diff line
		@@ -1325,29 +1325,23 @@ bgp_import_control(struct proto P, rte new, ea_list *attrs UNUSED, struct li

		static adata null_adata; /* adata of length 0 */

		static inline void
		bgp_cluster_list_prepend(ea_list *attrs, struct linpool pool, u32 id)
		{
		eattr a = bgp_find_attr(attrs, BA_CLUSTER_LIST);
		adata *d = int_set_add(pool, a ? a->u.ptr : NULL, id);
		bgp_set_attr_ptr(attrs, pool, BA_CLUSTER_LIST, 0, d);
		}

		static ea_list *
		bgp_update_attrs(struct bgp_proto p, struct bgp_channel c, rte e, ea_list attrs, struct linpool *pool)
		bgp_update_attrs(struct bgp_proto p, struct bgp_channel c, rte e, ea_list attrs0, struct linpool *pool)
		{
		struct proto *SRC = e->attrs->src->proto;
		struct bgp_proto src = (SRC->proto == &proto_bgp) ? (void ) SRC : NULL;
		struct bgp_export_state s = { .proto = p, .channel =c, .pool = pool, .src = src, .route = e };
		ea_list *attrs = attrs0;
		eattr *a;
		adata *ad;

		/* ORIGIN attribute - mandatory, attach if missing */
		if (! bgp_find_attr(attrs, BA_ORIGIN))
		if (! bgp_find_attr(attrs0, BA_ORIGIN))
		bgp_set_attr_u32(&attrs, pool, BA_ORIGIN, 0, src ? ORIGIN_INCOMPLETE : ORIGIN_IGP);

		/* AS_PATH attribute */
		a = bgp_find_attr(attrs, BA_AS_PATH);
		adata *ad = a ? a->u.ptr : &null_adata;
		/* AS_PATH attribute - mandatory */
		a = bgp_find_attr(attrs0, BA_AS_PATH);
		ad = a ? a->u.ptr : &null_adata;

		/* AS_PATH attribute - strip AS_CONFED* segments outside confederation */
		if ((!p->cf->confederation \|\| !p->is_interior) && as_path_contains_confed(ad))
		@@ -1374,33 +1368,40 @@ bgp_update_attrs(struct bgp_proto p, struct bgp_channel c, rte e, ea_list at
		bgp_set_attr_ptr(&attrs, pool, BA_AS_PATH, 0, ad);

		/* MULTI_EXIT_DESC attribute - accept only if set in export filter */
		a = bgp_find_attr(attrs, BA_MULTI_EXIT_DISC);
		a = bgp_find_attr(attrs0, BA_MULTI_EXIT_DISC);
		if (a && !(a->type & EAF_FRESH))
		bgp_unset_attr(&attrs, pool, BA_MULTI_EXIT_DISC);
		}

		/* NEXT_HOP attribute - delegated to AF-specific hook */
		a = bgp_find_attr(attrs, BA_NEXT_HOP);
		a = bgp_find_attr(attrs0, BA_NEXT_HOP);
		bgp_update_next_hop(&s, a, &attrs);

		/* LOCAL_PREF attribute - required for IBGP, attach if missing */
		if (p->is_interior && ! bgp_find_attr(attrs, BA_LOCAL_PREF))
		if (p->is_interior && ! bgp_find_attr(attrs0, BA_LOCAL_PREF))
		bgp_set_attr_u32(&attrs, pool, BA_LOCAL_PREF, 0, p->cf->default_local_pref);

		/* IBGP route reflection, RFC 4456 */
		if (src && src->is_internal && p->is_internal && (src->local_as == p->local_as))
		{
		/* ORIGINATOR_ID attribute - attach if not already set */
		if (! bgp_find_attr(attrs, BA_ORIGINATOR_ID))
		if (! bgp_find_attr(attrs0, BA_ORIGINATOR_ID))
		bgp_set_attr_u32(&attrs, pool, BA_ORIGINATOR_ID, 0, src->remote_id);

		/* CLUSTER_LIST attribute - prepend cluster ID */
		a = bgp_find_attr(attrs0, BA_CLUSTER_LIST);
		ad = a ? a->u.ptr : NULL;

		/* Prepend src cluster ID */
		if (src->rr_cluster_id)
		bgp_cluster_list_prepend(&attrs, pool, src->rr_cluster_id);
		ad = int_set_add(pool, ad, src->rr_cluster_id);

		/* Handle different src and dst cluster ID - prepend both ones */
		/* Prepend dst cluster ID if src and dst clusters are different */
		if (p->rr_cluster_id && (src->rr_cluster_id != p->rr_cluster_id))
		bgp_cluster_list_prepend(&attrs, pool, p->rr_cluster_id);
		ad = int_set_add(pool, ad, p->rr_cluster_id);

		/* Should be at least one prepended cluster ID */
		bgp_set_attr_ptr(&attrs, pool, BA_CLUSTER_LIST, 0, ad);
		}

		/* AS4_* transition attributes, RFC 6793 4.2.2 */
		@@ -1421,6 +1422,12 @@ bgp_update_attrs(struct bgp_proto p, struct bgp_channel c, rte e, ea_list at
		}
		}

		/*
		* Presence of mandatory attributes ORIGIN and AS_PATH is ensured by above
		* conditions. Presence and validity of quasi-mandatory NEXT_HOP attribute
		* should be checked in AF-specific hooks.
		*/

		/* Apply per-attribute export hooks for validatation and normalization */
		return bgp_export_attrs(&s, attrs);
		}

proto/bgp/bgp.h

+7 −11

Original line number	Diff line number	Diff line
		@@ -73,7 +73,7 @@ struct bgp_config {
		u16 local_port; /* Local listening port */
		u16 remote_port; /* Neighbor destination port */
		int multihop; /* Number of hops if multihop */
		int strict_bind; /* Bind listening socket to local address XXXX */
		int strict_bind; /* Bind listening socket to local address */
		int ttl_security; /* Enable TTL security [RFC 5082] */
		int compare_path_lengths; /* Use path lengths when selecting best route */
		int med_metric; /* Compare MULTI_EXIT_DISC even between routes from differen ASes */
		@@ -509,22 +509,18 @@ void bgp_update_next_hop(struct bgp_export_state s, eattr a, ea_list **to);
		#define BAF_PARTIAL 0x20
		#define BAF_EXT_LEN 0x10

		#define BA_ORIGIN 0x01 /* [RFC1771] / / WM */
		#define BA_ORIGIN 0x01 /* RFC 4271 / / WM */
		#define BA_AS_PATH 0x02 /* WM */
		#define BA_NEXT_HOP 0x03 /* WM */
		#define BA_MULTI_EXIT_DISC 0x04 /* ON */
		#define BA_LOCAL_PREF 0x05 /* WD */
		#define BA_ATOMIC_AGGR 0x06 /* WD */
		#define BA_AGGREGATOR 0x07 /* OT */
		#define BA_COMMUNITY 0x08 /* [RFC1997] / / OT */
		#define BA_ORIGINATOR_ID 0x09 /* [RFC1966] / / ON */
		#define BA_CLUSTER_LIST 0x0a /* ON */
		/* We don't support these: */
		#define BA_DPA 0x0b /* ??? */
		#define BA_ADVERTISER 0x0c /* [RFC1863] */
		#define BA_RCID_PATH 0x0d
		#define BA_MP_REACH_NLRI 0x0e /* [RFC2283] */
		#define BA_MP_UNREACH_NLRI 0x0f
		#define BA_COMMUNITY 0x08 /* RFC 1997 / / OT */
		#define BA_ORIGINATOR_ID 0x09 /* RFC 4456 / / ON */
		#define BA_CLUSTER_LIST 0x0a /* RFC 4456 / / ON */
		#define BA_MP_REACH_NLRI 0x0e /* RFC 4760 */
		#define BA_MP_UNREACH_NLRI 0x0f /* RFC 4760 */
		#define BA_EXT_COMMUNITY 0x10 /* RFC 4360 */
		#define BA_AS4_PATH 0x11 /* RFC 6793 */
		#define BA_AS4_AGGREGATOR 0x12 /* RFC 6793 */

proto/bgp/packets.c

+21 −12

Original line number	Diff line number	Diff line
		@@ -713,9 +713,13 @@ bgp_rx_open(struct bgp_conn conn, byte pkt, uint len)
		#define REPORT(msg, args...) \
		({ log(L_REMOTE "%s: " msg, s->proto->p.name, ## args); })

		#define DISCARD(msg, args...) \
		({ REPORT(msg, ## args); return; })

		#define WITHDRAW(msg, args...) \
		({ REPORT(msg, ## args); s->err_withdraw = 1; return; })

		#define BAD_AFI "Unexpected AF <%u/%u> in UPDATE"
		#define BAD_NEXT_HOP "Invalid NEXT_HOP attribute"
		#define NO_NEXT_HOP "Missing NEXT_HOP attribute"

		@@ -836,21 +840,27 @@ bgp_update_next_hop_ip(struct bgp_export_state s, eattr a, ea_list **to)
		static uint
		bgp_encode_next_hop_none(struct bgp_write_state s UNUSED, eattr a UNUSED, byte *buf UNUSED, uint size UNUSED)
		{
		// FIXME
		return 0;
		}

		static void
		bgp_decode_next_hop_none(struct bgp_parse_state s UNUSED, byte data UNUSED, uint len UNUSED, rta *a UNUSED)
		{
		// FIXME
		/*
		* Although we expect no next hop and RFC 7606 7.11 states that attribute
		* MP_REACH_NLRI with unexpected next hop length is considered malformed,
		* FlowSpec RFC 5575 4 states that next hop shall be ignored on receipt.
		*/

		return;
		}

		static void
		bgp_update_next_hop_none(struct bgp_export_state s UNUSED, eattr a UNUSED, ea_list **to UNUSED)
		bgp_update_next_hop_none(struct bgp_export_state s, eattr a, ea_list **to)
		{
		// FIXME
		/* NEXT_HOP shall not pass */
		if (a)
		bgp_unset_attr(to, s->pool, BA_NEXT_HOP);
		}


		@@ -1652,15 +1662,15 @@ bgp_create_end_mark(struct bgp_channel c, byte buf)
		}

		static inline void
		bgp_rx_end_mark(struct bgp_proto *p, u32 afi)
		bgp_rx_end_mark(struct bgp_parse_state *s, u32 afi)
		{
		struct bgp_proto *p = s->proto;
		struct bgp_channel *c = bgp_get_channel(p, afi);

		BGP_TRACE(D_PACKETS, "Got END-OF-RIB");

		/* XXXX handle unknown AF in MP__NLRI /
		if (!c)
		return;
		DISCARD(BAD_AFI, BGP_AFI(afi), BGP_SAFI(afi));

		if (c->load_state == BFS_LOADING)
		c->load_state = BFS_NONE;
		@@ -1678,9 +1688,8 @@ bgp_decode_nlri(struct bgp_parse_state s, u32 afi, byte nlri, uint len, ea_lis
		struct bgp_channel *c = bgp_get_channel(s->proto, afi);
		rta *a = NULL;

		/* XXXX handle unknown AF in MP__NLRI /
		if (!c)
		return;
		DISCARD(BAD_AFI, BGP_AFI(afi), BGP_SAFI(afi));

		s->channel = c;
		s->add_path = c->add_path_rx;
		@@ -1791,12 +1800,12 @@ bgp_rx_update(struct bgp_conn conn, byte pkt, uint len)

		/* Check for End-of-RIB marker */
		if (!s.attr_len && !s.ip_unreach_len && !s.ip_reach_len)
		{ bgp_rx_end_mark(p, BGP_AF_IPV4); goto done; }
		{ bgp_rx_end_mark(&s, BGP_AF_IPV4); goto done; }

		/* Check for MP End-of-RIB marker */
		if ((s.attr_len < 8) && !s.ip_unreach_len && !s.ip_reach_len &&
		!s.mp_reach_len && !s.mp_unreach_len && s.mp_unreach_af) /* XXXX See RFC 7606 5.2 */
		{ bgp_rx_end_mark(p, s.mp_unreach_af); goto done; }
		!s.mp_reach_len && !s.mp_unreach_len && s.mp_unreach_af)
		{ bgp_rx_end_mark(&s, s.mp_unreach_af); goto done; }

		if (s.ip_unreach_len)
		bgp_decode_nlri(&s, BGP_AF_IPV4, s.ip_unreach_nlri, s.ip_unreach_len, NULL, NULL, 0);

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