Merge pull request #2160 from donaldsharp/prefix_sid

bgpd: Handle multiple PREFIX_SID's at a time.

3 files changed, 99 insertions, 27 deletions

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index b6e9ee3cb2..276a7054e3 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2021,36 +2021,32 @@ static int bgp_attr_encap(uint8_t type, struct peer *peer, /* IN */
 	return 0;
 }
 
-/* Prefix SID attribute
- * draft-ietf-idr-bgp-prefix-sid-05
+/*
+ * Read an individual SID value returning how much data we have read
+ * Returns 0 if there was an error that needs to be passed up the stack
  */
-static bgp_attr_parse_ret_t
-bgp_attr_prefix_sid(struct bgp_attr_parser_args *args,
-		    struct bgp_nlri *mp_update)
+static bgp_attr_parse_ret_t bgp_attr_psid_sub(int32_t type,
+					      int32_t length,
+					      struct bgp_attr_parser_args *args,
+					      struct bgp_nlri *mp_update)
 {
 	struct peer *const peer = args->peer;
 	struct attr *const attr = args->attr;
-	int type;
-	int length;
 	uint32_t label_index;
 	struct in6_addr ipv6_sid;
 	uint32_t srgb_base;
 	uint32_t srgb_range;
 	int srgb_count;
 
-	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID);
-
-	type = stream_getc(peer->curr);
-	length = stream_getw(peer->curr);
-
 	if (type == BGP_PREFIX_SID_LABEL_INDEX) {
 		if (length != BGP_PREFIX_SID_LABEL_INDEX_LENGTH) {
 			zlog_err(
-				"Prefix SID label index length is %d instead of %d",
-				length, BGP_PREFIX_SID_LABEL_INDEX_LENGTH);
-			return bgp_attr_malformed(
-				args, BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
-				args->total);
+				 "Prefix SID label index length is %d instead of %d",
+				 length,
+				 BGP_PREFIX_SID_LABEL_INDEX_LENGTH);
+			return bgp_attr_malformed(args,
+						  BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+						  args->total);
 		}
 
 		/* Ignore flags and reserved */
@@ -2060,9 +2056,8 @@ bgp_attr_prefix_sid(struct bgp_attr_parser_args *args,
 		/* Fetch the label index and see if it is valid. */
 		label_index = stream_getl(peer->curr);
 		if (label_index == BGP_INVALID_LABEL_INDEX)
-			return bgp_attr_malformed(
-				args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
-				args->total);
+			return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_OPT_ATTR_ERR,
+						  args->total);
 
 		/* Store label index; subsequently, we'll check on
 		 * address-family */
@@ -2083,9 +2078,9 @@ bgp_attr_prefix_sid(struct bgp_attr_parser_args *args,
 		if (length != BGP_PREFIX_SID_IPV6_LENGTH) {
 			zlog_err("Prefix SID IPv6 length is %d instead of %d",
 				 length, BGP_PREFIX_SID_IPV6_LENGTH);
-			return bgp_attr_malformed(
-				args, BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
-				args->total);
+			return bgp_attr_malformed(args,
+						  BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+						  args->total);
 		}
 
 		/* Ignore reserved */
@@ -2122,6 +2117,47 @@ bgp_attr_prefix_sid(struct bgp_attr_parser_args *args,
 	return BGP_ATTR_PARSE_PROCEED;
 }
 
+/* Prefix SID attribute
+ * draft-ietf-idr-bgp-prefix-sid-05
+ */
+bgp_attr_parse_ret_t
+bgp_attr_prefix_sid(int32_t tlength, struct bgp_attr_parser_args *args,
+		    struct bgp_nlri *mp_update)
+{
+	struct peer *const peer = args->peer;
+	struct attr *const attr = args->attr;
+	bgp_attr_parse_ret_t ret;
+
+	attr->flag |= ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID);
+
+	while (tlength) {
+		int32_t type, length;
+
+		type = stream_getc(peer->curr);
+		length = stream_getw(peer->curr);
+
+		ret = bgp_attr_psid_sub(type, length, args, mp_update);
+
+		if (ret != BGP_ATTR_PARSE_PROCEED)
+			return ret;
+		/*
+		 * Subtract length + the T and the L
+		 * since length is the Vector portion
+		 */
+		tlength -= length + 3;
+
+		if (tlength < 0) {
+			zlog_err("Prefix SID internal length %d causes us to read beyond the total Prefix SID length",
+				 length);
+			return bgp_attr_malformed(args,
+						  BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+						  args->total);
+		}
+	}
+
+	return BGP_ATTR_PARSE_PROCEED;
+}
+
 /* PMSI tunnel attribute (RFC 6514)
  * Basic validation checks done here.
  */
@@ -2498,7 +2534,8 @@ bgp_attr_parse_ret_t bgp_attr_parse(struct peer *peer, struct attr *attr,
 					     startp);
 			break;
 		case BGP_ATTR_PREFIX_SID:
-			ret = bgp_attr_prefix_sid(&attr_args, mp_update);
+			ret = bgp_attr_prefix_sid(length,
+						  &attr_args, mp_update);
 			break;
 		case BGP_ATTR_PMSI_TUNNEL:
 			ret = bgp_attr_pmsi_tunnel(&attr_args);
diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index d59eae5f14..f17c2a68e4 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -308,6 +308,9 @@ extern int bgp_mp_reach_parse(struct bgp_attr_parser_args *args,
 			      struct bgp_nlri *);
 extern int bgp_mp_unreach_parse(struct bgp_attr_parser_args *args,
 				struct bgp_nlri *);
+extern bgp_attr_parse_ret_t
+bgp_attr_prefix_sid(int32_t tlength, struct bgp_attr_parser_args *args,
+		    struct bgp_nlri *mp_update);
 
 extern struct bgp_attr_encap_subtlv *
 encap_tlv_dup(struct bgp_attr_encap_subtlv *orig);
diff --git a/tests/bgpd/test_mp_attr.c b/tests/bgpd/test_mp_attr.c
index 9e0cb1f5ca..8db1cb2ca1 100644
--- a/tests/bgpd/test_mp_attr.c
+++ b/tests/bgpd/test_mp_attr.c
@@ -945,6 +945,24 @@ static struct test_segment mp_unreach_segments[] = {
 	},
 	{NULL, NULL, {0}, 0, 0}};
 
+static struct test_segment mp_prefix_sid[] = {
+	{
+		"PREFIX-SID",
+		"PREFIX-SID Test 1",
+		{
+			0x01, 0x00, 0x07,
+			0x00, 0x00, 0x00, 0x00,
+			0x00, 0x00, 0x02,
+			0x03, 0x00, 0x08, 0x00,
+			0x00, 0x0a, 0x1b, 0xfe,
+			0x00, 0x00, 0x0a
+		},
+		.len = 21,
+		.parses = SHOULD_PARSE,
+	},
+	{NULL, NULL, { 0 }, 0, 0},
+};
+
 /* nlri_parse indicates 0 on successful parse, and -1 otherwise.
  * attr_parse indicates BGP_ATTR_PARSE_PROCEED/0 on success,
  * and BGP_ATTR_PARSE_ERROR/-1 or lower negative ret on err.
@@ -1000,10 +1018,20 @@ static void parse_test(struct peer *peer, struct test_segment *t, int type)
 
 	printf("%s: %s\n", t->name, t->desc);
 
-	if (type == BGP_ATTR_MP_REACH_NLRI)
+	switch (type) {
+	case BGP_ATTR_MP_REACH_NLRI:
 		parse_ret = bgp_mp_reach_parse(&attr_args, &nlri);
-	else
+		break;
+	case BGP_ATTR_MP_UNREACH_NLRI:
 		parse_ret = bgp_mp_unreach_parse(&attr_args, &nlri);
+		break;
+	case BGP_ATTR_PREFIX_SID:
+		parse_ret = bgp_attr_prefix_sid(t->len, &attr_args, &nlri);
+		break;
+	default:
+		printf("unknown type");
+		return;
+	}
 	if (!parse_ret) {
 		iana_afi_t pkt_afi;
 		iana_safi_t pkt_safi;
@@ -1022,7 +1050,7 @@ static void parse_test(struct peer *peer, struct test_segment *t, int type)
 	if (!parse_ret) {
 		if (type == BGP_ATTR_MP_REACH_NLRI)
 			nlri_ret = bgp_nlri_parse(peer, &attr, &nlri, 0);
-		else
+		else if (type == BGP_ATTR_MP_UNREACH_NLRI)
 			nlri_ret = bgp_nlri_parse(peer, &attr, &nlri, 1);
 	}
 	handle_result(peer, t, parse_ret, nlri_ret);
@@ -1085,6 +1113,10 @@ int main(void)
 		parse_test(peer, &mp_unreach_segments[i++],
 			   BGP_ATTR_MP_UNREACH_NLRI);
 
+	i = 0;
+	while (mp_prefix_sid[i].name)
+		parse_test(peer, &mp_prefix_sid[i++],
+			   BGP_ATTR_PREFIX_SID);
 	printf("failures: %d\n", failed);
 	return failed;
 }