bgpd: Move link_bw from attr_extra to bgp_path_info_extra

attr and attr_extra are "designed" for BGP attributes, but link_bw is not an
actual BGP attribute, it's derived from Extended Community.

Let's move it to bgp_path_info_extra.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

Author: ton31337

bgpd/bgp_attr.c

@@ -1705,8 +1705,6 @@ void bgp_attr_unintern_sub(struct attr *attr)
 
 	bgp_attr_unset_aigp_metric(attr);
 
-	bgp_attr_set_link_bw(attr, 0);
-
 	bgp_attr_set_pmsi_tnl_type(attr, PMSI_TNLTYPE_NO_INFO);
 
 	XFREE(MTYPE_ATTR_EXTRA, attr->extra);
@@ -1842,8 +1840,6 @@ void bgp_attr_flush(struct attr *attr)
 
 	bgp_attr_unset_aigp_metric(attr);
 
-	bgp_attr_set_link_bw(attr, 0);
-
 	bgp_attr_set_pmsi_tnl_type(attr, PMSI_TNLTYPE_NO_INFO);
 
 	XFREE(MTYPE_ATTR_EXTRA, attr->extra);
@@ -3198,14 +3194,6 @@ bgp_attr_ext_communities(struct bgp_attr_parser_args *args)
 	bgp_attr_extcom_tunnel_type(attr, &tun_type);
 	attr->encap_tunneltype = tun_type;
 
-	/* Extract link bandwidth, if any. */
-	{
-		uint64_t link_bw = 0;
-
-		(void)ecommunity_linkbw_present(bgp_attr_get_ecommunity(attr), &link_bw);
-		bgp_attr_set_link_bw(attr, link_bw);
-	}
-
 	return BGP_ATTR_PARSE_PROCEED;
 }
 
@@ -3238,14 +3226,6 @@ bgp_attr_ipv6_ext_communities(struct bgp_attr_parser_args *args)
 		return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
 					  args->total);
 
-	/* Extract link bandwidth, if any. */
-	{
-		uint64_t link_bw = 0;
-
-		(void)ecommunity_linkbw_present(bgp_attr_get_ipv6_ecommunity(attr), &link_bw);
-		bgp_attr_set_link_bw(attr, link_bw);
-	}
-
 	return BGP_ATTR_PARSE_PROCEED;
 
 ipv6_ext_community_ignore:

bgpd/bgp_attr.h

@@ -148,9 +148,6 @@ struct attr_extra {
 	/* For BGP-LS Attribute (RFC 9552) */
 	struct bgp_ls_attr *ls_attr;
 
-	/* Link bandwidth value extracted from ecommunity, if any. */
-	uint64_t link_bw;
-
 	/* SRv6 VPN SID */
 	struct bgp_attr_srv6_vpn *srv6_vpn;
 
@@ -809,25 +806,6 @@ static inline void bgp_attr_set_ls_attr(struct attr *attr, struct bgp_ls_attr *l
 		bgp_attr_unset(attr, BGP_ATTR_LINK_STATE);
 }
 
-static inline uint64_t bgp_attr_get_link_bw(const struct attr *attr)
-{
-	return attr->extra ? attr->extra->link_bw : 0;
-}
-
-static inline void bgp_attr_set_link_bw(struct attr *attr, uint64_t link_bw)
-{
-	uint64_t old = bgp_attr_get_link_bw(attr);
-
-	if (link_bw && !old) {
-		bgp_attr_extra_get(attr)->link_bw = link_bw;
-	} else if (link_bw && old) {
-		attr->extra->link_bw = link_bw; /* replace; refcnt unchanged */
-	} else if (!link_bw && old) {
-		attr->extra->link_bw = 0;
-		bgp_attr_extra_put(attr);
-	}
-}
-
 static inline uint32_t bgp_attr_get_otc(const struct attr *attr)
 {
 	return attr->extra ? attr->extra->otc : 0;

bgpd/bgp_route.c

@@ -433,6 +433,24 @@ uint32_t bgp_path_info_get_srte_color(struct bgp_path_info *bpi)
 	return 0;
 }
 
+/* Extract link bandwidth from the BGP path's extended communities.
+ * Falls back to the IPv6 address-specific extended community when no
+ * link-bandwidth value is encoded in the standard extended community.
+ */
+uint64_t bgp_path_info_get_link_bw(struct bgp_path_info *bpi)
+{
+	uint64_t link_bw = 0;
+
+	if (!bpi || !bpi->attr)
+		return 0;
+
+	(void)ecommunity_linkbw_present(bgp_attr_get_ecommunity(bpi->attr), &link_bw);
+	if (!link_bw)
+		(void)ecommunity_linkbw_present(bgp_attr_get_ipv6_ecommunity(bpi->attr), &link_bw);
+
+	return link_bw;
+}
+
 bool bgp_path_info_has_valid_label(const struct bgp_path_info *path)
 {
 	if (!BGP_PATH_INFO_NUM_LABELS(path))

bgpd/bgp_route.h

@@ -1072,4 +1072,5 @@ extern uint32_t bgp_med_value(struct attr *attr, struct bgp *bgp);
 extern int bgp_dest_set_defer_flag(struct bgp_dest *dest, bool delete);
 extern void bgp_process_main_one(struct bgp *bgp, struct bgp_dest *dest, afi_t afi, safi_t safi);
 extern uint32_t bgp_path_info_get_srte_color(struct bgp_path_info *bpi);
+extern uint64_t bgp_path_info_get_link_bw(struct bgp_path_info *bpi);
 #endif /* _QUAGGA_BGP_ROUTE_H */

bgpd/bgp_zebra.c

@@ -1268,13 +1268,13 @@ static bool update_ipv6nh_for_route_install(int nh_othervrf, struct bgp *nh_bgp,
 	return true;
 }
 
-static bool bgp_zebra_use_nhop_weighted(struct bgp *bgp, struct attr *attr,
+static bool bgp_zebra_use_nhop_weighted(struct bgp *bgp, struct bgp_path_info *bpi,
 					uint64_t *nh_weight)
 {
 	/* zero link-bandwidth and link-bandwidth not present are treated
 	 * as the same situation.
 	 */
-	uint64_t link_bw = bgp_attr_get_link_bw(attr);
+	uint64_t link_bw = bgp_path_info_get_link_bw(bpi);
 
 	if (!link_bw) {
 		/* the only situations should be if we're either told
@@ -1355,22 +1355,7 @@ static void bgp_zebra_announce_parse_nexthop(struct bgp_path_info *info, const s
 		 * in some situations.
 		 */
 		if (do_wt_ecmp == BGP_WECMP_BEHAVIOR_LINK_BW) {
-			/* Extended communities are exported/imported correctly
-			 * between VRFs, but we need to extract the actual link-bandwidth
-			 * value from the extended communities.
-			 */
-			uint64_t link_bw = 0;
-
-			(void)ecommunity_linkbw_present(bgp_attr_get_ecommunity(mpinfo->attr),
-							&link_bw);
-			/* Fallback to IPv6 address-specific extended community */
-			if (!link_bw)
-				(void)ecommunity_linkbw_present(bgp_attr_get_ipv6_ecommunity(
-									mpinfo->attr),
-								&link_bw);
-			bgp_attr_set_link_bw(mpinfo->attr, link_bw);
-			if (!bgp_zebra_use_nhop_weighted(bgp, mpinfo->attr,
-							 &nh_weight))
+			if (!bgp_zebra_use_nhop_weighted(bgp, mpinfo, &nh_weight))
 				continue;
 		} else if (do_wt_ecmp == BGP_WECMP_BEHAVIOR_NNHN_COUNT) {
 			if (bgp_attr_exists(mpinfo->attr, BGP_ATTR_NHC))