bgpd: Add neighbor PEER link-bw-encoding-ieee

This is to avoid breaking changes between existing deployments of
extended community for bandwidth encoding. By default FRR uses uint32
to encode bandwidth, which is not as the draft requires (IEEE floating-point).

This switch enables the required encoding per-peer.

Signed-off-by: Donatas Abraitis <donatas.abraitis@gmail.com>

bgpd/bgp_attr.c

@@ -2311,8 +2311,10 @@ bgp_attr_ext_communities(struct bgp_attr_parser_args *args)
 					  args->total);
 	}
 
-	attr->ecommunity =
-		ecommunity_parse(stream_pnt(peer->curr), length);
+	attr->ecommunity = ecommunity_parse(
+		stream_pnt(peer->curr), length,
+		CHECK_FLAG(peer->flags,
+			   PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE));
 	/* XXX: fix ecommunity_parse to use stream API */
 	stream_forward_getp(peer->curr, length);
 
@@ -2380,7 +2382,10 @@ bgp_attr_ipv6_ext_communities(struct bgp_attr_parser_args *args)
 					  args->total);
 	}
 
-	ipv6_ecomm = ecommunity_parse_ipv6(stream_pnt(peer->curr), length);
+	ipv6_ecomm = ecommunity_parse_ipv6(
+		stream_pnt(peer->curr), length,
+		CHECK_FLAG(peer->flags,
+			   PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE));
 	bgp_attr_set_ipv6_ecommunity(attr, ipv6_ecomm);
 
 	/* XXX: fix ecommunity_parse to use stream API */

bgpd/bgp_ecommunity.c

@@ -201,6 +201,7 @@ ecommunity_uniq_sort_internal(struct ecommunity *ecom,
 
 	new = ecommunity_new();
 	new->unit_size = ecom_size;
+	new->disable_ieee_floating = ecom->disable_ieee_floating;
 
 	for (i = 0; i < ecom->size; i++) {
 		eval = (void *)(ecom->val + (i * ecom_size));
@@ -220,8 +221,9 @@ struct ecommunity *ecommunity_uniq_sort(struct ecommunity *ecom)
 
 /* Parse Extended Communites Attribute in BGP packet.  */
 static struct ecommunity *ecommunity_parse_internal(uint8_t *pnt,
-					unsigned short length,
-					unsigned short size_ecom)
+						    unsigned short length,
+						    unsigned short size_ecom,
+						    bool disable_ieee_floating)
 {
 	struct ecommunity tmp;
 	struct ecommunity *new;
@@ -234,6 +236,7 @@ static struct ecommunity *ecommunity_parse_internal(uint8_t *pnt,
 	   Attribute.  */
 	tmp.size = length / size_ecom;
 	tmp.val = pnt;
+	tmp.disable_ieee_floating = disable_ieee_floating;
 
 	/* Create a new Extended Communities Attribute by uniq and sort each
 	   Extended Communities value  */
@@ -242,17 +245,18 @@ static struct ecommunity *ecommunity_parse_internal(uint8_t *pnt,
 	return ecommunity_intern(new);
 }
 
-struct ecommunity *ecommunity_parse(uint8_t *pnt,
-				    unsigned short length)
+struct ecommunity *ecommunity_parse(uint8_t *pnt, unsigned short length,
+				    bool disable_ieee_floating)
 {
-	return ecommunity_parse_internal(pnt, length, ECOMMUNITY_SIZE);
+	return ecommunity_parse_internal(pnt, length, ECOMMUNITY_SIZE,
+					 disable_ieee_floating);
 }
 
-struct ecommunity *ecommunity_parse_ipv6(uint8_t *pnt,
-					 unsigned short length)
+struct ecommunity *ecommunity_parse_ipv6(uint8_t *pnt, unsigned short length,
+					 bool disable_ieee_floating)
 {
-	return ecommunity_parse_internal(pnt, length,
-					 IPV6_ECOMMUNITY_SIZE);
+	return ecommunity_parse_internal(pnt, length, IPV6_ECOMMUNITY_SIZE,
+					 disable_ieee_floating);
 }
 
 /* Duplicate the Extended Communities Attribute structure.  */
@@ -847,7 +851,8 @@ static uint32_t ieee_float_uint32_to_uint32(uint32_t u)
 	return (uint32_t)f.r;
 }
 
-static int ecommunity_lb_str(char *buf, size_t bufsz, const uint8_t *pnt)
+static int ecommunity_lb_str(char *buf, size_t bufsz, const uint8_t *pnt,
+			     bool disable_ieee_floating)
 {
 	int len = 0;
 	as_t as;
@@ -862,7 +867,8 @@ static int ecommunity_lb_str(char *buf, size_t bufsz, const uint8_t *pnt)
 	as |= (*pnt++);
 	(void)ptr_get_be32(pnt, &bw_tmp);
 
-	bw = ieee_float_uint32_to_uint32(bw_tmp);
+	bw = disable_ieee_floating ? bw_tmp
+				   : ieee_float_uint32_to_uint32(bw_tmp);
 
 	if (bw >= ONE_GBPS_BYTES)
 		snprintf(bps_buf, sizeof(bps_buf), "%.3f Gbps",
@@ -954,8 +960,9 @@ char *ecommunity_ecom2str(struct ecommunity *ecom, int format, int filter)
 				} else if (sub_type ==
 					   ECOMMUNITY_LINK_BANDWIDTH &&
 					   type == ECOMMUNITY_ENCODE_AS) {
-					ecommunity_lb_str(encbuf,
-						sizeof(encbuf), pnt);
+					ecommunity_lb_str(
+						encbuf, sizeof(encbuf), pnt,
+						ecom->disable_ieee_floating);
 				} else
 					unk_ecom = 1;
 			} else {
@@ -1161,7 +1168,8 @@ char *ecommunity_ecom2str(struct ecommunity *ecom, int format, int filter)
 		} else if (type == ECOMMUNITY_ENCODE_AS_NON_TRANS) {
 			sub_type = *pnt++;
 			if (sub_type == ECOMMUNITY_LINK_BANDWIDTH)
-				ecommunity_lb_str(encbuf, sizeof(encbuf), pnt);
+				ecommunity_lb_str(encbuf, sizeof(encbuf), pnt,
+						  ecom->disable_ieee_floating);
 			else
 				unk_ecom = 1;
 		} else {
@@ -1547,7 +1555,10 @@ const uint8_t *ecommunity_linkbw_present(struct ecommunity *ecom, uint32_t *bw)
 			pnt = ptr_get_be32(pnt, &bwval);
 			(void)pnt; /* consume value */
 			if (bw)
-				*bw = ieee_float_uint32_to_uint32(bwval);
+				*bw = ecom->disable_ieee_floating
+					      ? bwval
+					      : ieee_float_uint32_to_uint32(
+							bwval);
 			return eval;
 		}
 	}
@@ -1556,9 +1567,9 @@ const uint8_t *ecommunity_linkbw_present(struct ecommunity *ecom, uint32_t *bw)
 }
 
 
-struct ecommunity *ecommunity_replace_linkbw(as_t as,
-					     struct ecommunity *ecom,
-					     uint64_t cum_bw)
+struct ecommunity *ecommunity_replace_linkbw(as_t as, struct ecommunity *ecom,
+					     uint64_t cum_bw,
+					     bool disable_ieee_floating)
 {
 	struct ecommunity *new;
 	struct ecommunity_val lb_eval;
@@ -1588,8 +1599,8 @@ struct ecommunity *ecommunity_replace_linkbw(as_t as,
 	 */
 	if (cum_bw > 0xFFFFFFFF)
 		cum_bw = 0xFFFFFFFF;
-	encode_lb_extcomm(as > BGP_AS_MAX ? BGP_AS_TRANS : as, cum_bw,
-			  false, &lb_eval);
+	encode_lb_extcomm(as > BGP_AS_MAX ? BGP_AS_TRANS : as, cum_bw, false,
+			  &lb_eval, disable_ieee_floating);
 	new = ecommunity_dup(ecom);
 	ecommunity_add_val(new, &lb_eval, true, true);
 

bgpd/bgp_ecommunity.h

@@ -124,6 +124,9 @@ struct ecommunity {
 
 	/* Human readable format string.  */
 	char *str;
+
+	/* Disable IEEE floating-point encoding for extended community */
+	bool disable_ieee_floating;
 };
 
 struct ecommunity_as {
@@ -214,9 +217,11 @@ static uint32_t uint32_to_ieee_float_uint32(uint32_t u)
  *  bandwidth (bw) is in bytes-per-sec
  */
 static inline void encode_lb_extcomm(as_t as, uint32_t bw, bool non_trans,
-				     struct ecommunity_val *eval)
+				     struct ecommunity_val *eval,
+				     bool disable_ieee_floating)
 {
-	uint32_t bandwidth = uint32_to_ieee_float_uint32(bw);
+	uint32_t bandwidth =
+		disable_ieee_floating ? bw : uint32_to_ieee_float_uint32(bw);
 
 	memset(eval, 0, sizeof(*eval));
 	eval->val[0] = ECOMMUNITY_ENCODE_AS;
@@ -234,9 +239,11 @@ static inline void encode_lb_extcomm(as_t as, uint32_t bw, bool non_trans,
 extern void ecommunity_init(void);
 extern void ecommunity_finish(void);
 extern void ecommunity_free(struct ecommunity **);
-extern struct ecommunity *ecommunity_parse(uint8_t *, unsigned short);
+extern struct ecommunity *ecommunity_parse(uint8_t *, unsigned short,
+					   bool disable_ieee_floating);
 extern struct ecommunity *ecommunity_parse_ipv6(uint8_t *pnt,
-						unsigned short length);
+						unsigned short length,
+						bool disable_ieee_floating);
 extern struct ecommunity *ecommunity_dup(struct ecommunity *);
 extern struct ecommunity *ecommunity_merge(struct ecommunity *,
 					   struct ecommunity *);
@@ -294,7 +301,9 @@ extern void bgp_aggr_ecommunity_remove(void *arg);
 extern const uint8_t *ecommunity_linkbw_present(struct ecommunity *ecom,
 						uint32_t *bw);
 extern struct ecommunity *ecommunity_replace_linkbw(as_t as,
-				struct ecommunity *ecom, uint64_t cum_bw);
+						    struct ecommunity *ecom,
+						    uint64_t cum_bw,
+						    bool disable_ieee_floating);
 
 static inline void ecommunity_strip_rts(struct ecommunity *ecom)
 {

bgpd/bgp_mpath.c

@@ -610,7 +610,8 @@ void bgp_path_info_mpath_update(struct bgp_dest *dest,
 				prev_mpath = cur_mpath;
 				mpath_count++;
 				if (ecommunity_linkbw_present(
-					cur_mpath->attr->ecommunity, &bwval))
+					    cur_mpath->attr->ecommunity,
+					    &bwval))
 					cum_bw += bwval;
 				else
 					all_paths_lb = false;
@@ -699,7 +700,8 @@ void bgp_path_info_mpath_update(struct bgp_dest *dest,
 				mpath_changed = 1;
 				mpath_count++;
 				if (ecommunity_linkbw_present(
-					new_mpath->attr->ecommunity, &bwval))
+					    new_mpath->attr->ecommunity,
+					    &bwval))
 					cum_bw += bwval;
 				else
 					all_paths_lb = false;
@@ -721,9 +723,9 @@ void bgp_path_info_mpath_update(struct bgp_dest *dest,
 
 	if (new_best) {
 		bgp_path_info_mpath_count_set(new_best, mpath_count - 1);
-		if (mpath_count <= 1 ||
-		    !ecommunity_linkbw_present(
-			new_best->attr->ecommunity, &bwval))
+		if (mpath_count <= 1
+		    || !ecommunity_linkbw_present(new_best->attr->ecommunity,
+						  &bwval))
 			all_paths_lb = false;
 		else
 			cum_bw += bwval;

bgpd/bgp_route.c

@@ -2276,7 +2276,9 @@ bool subgroup_announce_check(struct bgp_dest *dest, struct bgp_path_info *pi,
 	    (cum_bw = bgp_path_info_mpath_cumbw(pi)) != 0 &&
 	    !CHECK_FLAG(attr->rmap_change_flags, BATTR_RMAP_LINK_BW_SET))
 		attr->ecommunity = ecommunity_replace_linkbw(
-					bgp->as, attr->ecommunity, cum_bw);
+			bgp->as, attr->ecommunity, cum_bw,
+			CHECK_FLAG(peer->flags,
+				   PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE));
 
 	return true;
 }

bgpd/bgp_routemap.c

@@ -2658,7 +2658,9 @@ route_set_ecommunity_lb(void *rule, const struct prefix *prefix, void *object)
 		bw_bytes *= mpath_count;
 	}
 
-	encode_lb_extcomm(as, bw_bytes, rels->non_trans, &lb_eval);
+	encode_lb_extcomm(as, bw_bytes, rels->non_trans, &lb_eval,
+			  CHECK_FLAG(peer->flags,
+				     PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE));
 
 	/* add to route or merge with existing */
 	old_ecom = path->attr->ecommunity;

bgpd/bgp_vty.c

@@ -6138,6 +6138,29 @@ DEFUN (no_neighbor_disable_connected_check,
 				   PEER_FLAG_DISABLE_CONNECTED_CHECK);
 }
 
+/* link-bw-encoding-ieee */
+DEFUN(neighbor_link_bw_encoding_ieee, neighbor_link_bw_encoding_ieee_cmd,
+      "neighbor <A.B.C.D|X:X::X:X|WORD> disable-link-bw-encoding-ieee",
+      NEIGHBOR_STR NEIGHBOR_ADDR_STR2
+      "Enable IEEE floating-point encoding for extended community bandwidth\n")
+{
+	int idx_peer = 1;
+
+	return peer_flag_set_vty(vty, argv[idx_peer]->arg,
+				 PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE);
+}
+
+DEFUN(no_neighbor_link_bw_encoding_ieee, no_neighbor_link_bw_encoding_ieee_cmd,
+      "no neighbor <A.B.C.D|X:X::X:X|WORD> disable-link-bw-encoding-ieee",
+      NO_STR NEIGHBOR_STR NEIGHBOR_ADDR_STR2
+      "Enable IEEE floating-point encoding for extended community bandwidth\n")
+{
+	int idx_peer = 2;
+
+	return peer_flag_unset_vty(vty, argv[idx_peer]->arg,
+				   PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE);
+}
+
 
 /* enforce-first-as */
 DEFUN (neighbor_enforce_first_as,
@@ -16347,6 +16370,11 @@ static void bgp_config_write_peer_global(struct vty *vty, struct bgp *bgp,
 	if (peergroup_flag_check(peer, PEER_FLAG_DISABLE_CONNECTED_CHECK))
 		vty_out(vty, " neighbor %s disable-connected-check\n", addr);
 
+	/* link-bw-encoding-ieee */
+	if (peergroup_flag_check(peer, PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE))
+		vty_out(vty, " neighbor %s disable-link-bw-encoding-ieee\n",
+			addr);
+
 	/* enforce-first-as */
 	if (peergroup_flag_check(peer, PEER_FLAG_ENFORCE_FIRST_AS))
 		vty_out(vty, " neighbor %s enforce-first-as\n", addr);
@@ -18240,6 +18268,10 @@ void bgp_vty_init(void)
 	install_element(BGP_NODE, &neighbor_disable_connected_check_cmd);
 	install_element(BGP_NODE, &no_neighbor_disable_connected_check_cmd);
 
+	/* "neighbor link-bw-encoding-ieee" commands.  */
+	install_element(BGP_NODE, &neighbor_link_bw_encoding_ieee_cmd);
+	install_element(BGP_NODE, &no_neighbor_link_bw_encoding_ieee_cmd);
+
 	/* "neighbor enforce-first-as" commands. */
 	install_element(BGP_NODE, &neighbor_enforce_first_as_cmd);
 	install_element(BGP_NODE, &no_neighbor_enforce_first_as_cmd);

bgpd/bgpd.c

@@ -4164,6 +4164,7 @@ static const struct peer_flag_action peer_flag_action_list[] = {
 	{PEER_FLAG_LOCAL_AS_NO_PREPEND, 0, peer_change_none},
 	{PEER_FLAG_LOCAL_AS_REPLACE_AS, 0, peer_change_none},
 	{PEER_FLAG_UPDATE_SOURCE, 0, peer_change_none},
+	{PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE, 0, peer_change_none},
 	{0, 0, 0}};
 
 static const struct peer_flag_action peer_af_flag_action_list[] = {

bgpd/bgpd.h

@@ -1283,6 +1283,10 @@ struct peer {
 #define PEER_FLAG_RTT_SHUTDOWN (1U << 26) /* shutdown rtt */
 #define PEER_FLAG_TIMER_DELAYOPEN (1U << 27) /* delayopen timer */
 #define PEER_FLAG_TCP_MSS (1U << 28)	 /* tcp-mss */
+/* Disable IEEE floating-point link bandwidth encoding in
+ * extended communities.
+ */
+#define PEER_FLAG_DISABLE_LINK_BW_ENCODING_IEEE (1U << 29)
 
 	/*
 	 *GR-Disabled mode means unset PEER_FLAG_GRACEFUL_RESTART

tests/bgpd/test_ecommunity.c

@@ -121,7 +121,7 @@ static void parse_test(struct test_segment *t)
 
 	printf("%s: %s\n", t->name, t->desc);
 
-	ecom = ecommunity_parse((uint8_t *)t->data, t->len);
+	ecom = ecommunity_parse((uint8_t *)t->data, t->len, 0);
 
 	printf("ecom: %s\nvalidating...:\n", ecommunity_str(ecom));