bgpd: fix parser of srv6 infomation

bgpd couldn't parse SRv6 SID Information Sub-TLV correctly.
draft-ietf-bess-srv6-services-07 also defines SRv6 SID Structure
Sub-Sub-TLV. This patch adds the parser for SRv6 SID Structure
Sub-Sub-TLV.

Signed-off-by: Ryoga Saito <contact@proelbtn.com>

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index c4d159afd09181dd4963e16909d365425b729790..1ee92198ddeedb845fdec07bcd0940281ae04cd3 100644 (file)
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2524,6 +2524,152 @@ static int bgp_attr_encap(uint8_t type, struct peer *peer, /* IN */
        return 0;
 }
 
+
+/* SRv6 Service Data Sub-Sub-TLV attribute
+ * draft-ietf-bess-srv6-services-07
+ */
+static bgp_attr_parse_ret_t
+bgp_attr_srv6_service_data(struct bgp_attr_parser_args *args)
+{
+       struct peer *const peer = args->peer;
+       uint8_t type, loc_block_len, loc_node_len, func_len, arg_len,
+               transposition_len, transposition_offset;
+       uint16_t length;
+       size_t headersz = sizeof(type) + sizeof(length);
+
+       if (STREAM_READABLE(peer->curr) < headersz) {
+               flog_err(
+                       EC_BGP_ATTR_LEN,
+                       "Malformed SRv6 Service Data Sub-Sub-TLV attribute - insufficent data (need %zu for attribute header, have %zu remaining in UPDATE)",
+                       headersz, STREAM_READABLE(peer->curr));
+               return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+                                         args->total);
+       }
+
+       type = stream_getc(peer->curr);
+       length = stream_getw(peer->curr);
+
+       if (STREAM_READABLE(peer->curr) < length) {
+               flog_err(
+                       EC_BGP_ATTR_LEN,
+                       "Malformed SRv6 Service Data Sub-Sub-TLV attribute - insufficent data (need %hu for attribute data, have %zu remaining in UPDATE)",
+                       length, STREAM_READABLE(peer->curr));
+               return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+                                         args->total);
+       }
+
+       if (type == BGP_PREFIX_SID_SRV6_L3_SERVICE_SID_STRUCTURE) {
+               loc_block_len = stream_getc(peer->curr);
+               loc_node_len = stream_getc(peer->curr);
+               func_len = stream_getc(peer->curr);
+               arg_len = stream_getc(peer->curr);
+               transposition_len = stream_getc(peer->curr);
+               transposition_offset = stream_getc(peer->curr);
+
+               /* Log SRv6 Service Data Sub-Sub-TLV */
+               if (BGP_DEBUG(vpn, VPN_LEAK_LABEL)) {
+                       zlog_debug(
+                               "%s: srv6-l3-srv-data loc-block-len=%u, loc-node-len=%u func-len=%u, arg-len=%u, transposition-len=%u, transposition-offset=%u",
+                               __func__, loc_block_len, loc_node_len, func_len,
+                               arg_len, transposition_len,
+                               transposition_offset);
+               }
+       }
+
+       else {
+               if (bgp_debug_update(peer, NULL, NULL, 1))
+                       zlog_debug(
+                               "%s attr SRv6 Service Data Sub-Sub-TLV sub-sub-type=%u is not supported, skipped",
+                               peer->host, type);
+
+               stream_forward_getp(peer->curr, length);
+       }
+
+       return BGP_ATTR_PARSE_PROCEED;
+}
+
+/* SRv6 Service Sub-TLV attribute
+ * draft-ietf-bess-srv6-services-07
+ */
+static bgp_attr_parse_ret_t
+bgp_attr_srv6_service(struct bgp_attr_parser_args *args)
+{
+       struct peer *const peer = args->peer;
+       struct attr *const attr = args->attr;
+       struct in6_addr ipv6_sid;
+       uint8_t type, sid_flags;
+       uint16_t length, endpoint_behavior;
+       size_t headersz = sizeof(type) + sizeof(length);
+       char buf[BUFSIZ];
+
+       if (STREAM_READABLE(peer->curr) < headersz) {
+               flog_err(
+                       EC_BGP_ATTR_LEN,
+                       "Malformed SRv6 Service Sub-TLV attribute - insufficent data (need %zu for attribute header, have %zu remaining in UPDATE)",
+                       headersz, STREAM_READABLE(peer->curr));
+               return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+                                         args->total);
+       }
+
+       type = stream_getc(peer->curr);
+       length = stream_getw(peer->curr);
+
+       if (STREAM_READABLE(peer->curr) < length) {
+               flog_err(
+                       EC_BGP_ATTR_LEN,
+                       "Malformed SRv6 Service Sub-TLV attribute - insufficent data (need %hu for attribute data, have %zu remaining in UPDATE)",
+                       length, STREAM_READABLE(peer->curr));
+               return bgp_attr_malformed(args, BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
+                                         args->total);
+       }
+
+       if (type == BGP_PREFIX_SID_SRV6_L3_SERVICE_SID_INFO) {
+               stream_getc(peer->curr);
+               stream_get(&ipv6_sid, peer->curr, sizeof(ipv6_sid));
+               sid_flags = stream_getc(peer->curr);
+               endpoint_behavior = stream_getw(peer->curr);
+               stream_getc(peer->curr);
+
+               /* Log SRv6 Service Sub-TLV */
+               if (BGP_DEBUG(vpn, VPN_LEAK_LABEL)) {
+                       inet_ntop(AF_INET6, &ipv6_sid, buf, sizeof(buf));
+                       zlog_debug(
+                               "%s: srv6-l3-srv sid %s, sid-flags 0x%02x, end-behaviour 0x%04x",
+                               __func__, buf, sid_flags, endpoint_behavior);
+               }
+
+               /* Configure from Info */
+               if (attr->srv6_l3vpn) {
+                       flog_err(EC_BGP_ATTRIBUTE_REPEATED,
+                                "Prefix SID SRv6 L3VPN field repeated");
+                       return bgp_attr_malformed(
+                               args, BGP_NOTIFY_UPDATE_MAL_ATTR, args->total);
+               }
+               attr->srv6_l3vpn = XCALLOC(MTYPE_BGP_SRV6_L3VPN,
+                                          sizeof(struct bgp_attr_srv6_l3vpn));
+               attr->srv6_l3vpn->sid_flags = sid_flags;
+               attr->srv6_l3vpn->endpoint_behavior = endpoint_behavior;
+               sid_copy(&attr->srv6_l3vpn->sid, &ipv6_sid);
+               attr->srv6_l3vpn = srv6_l3vpn_intern(attr->srv6_l3vpn);
+
+               // Sub-Sub-TLV found
+               if (length > BGP_PREFIX_SID_SRV6_L3_SERVICE_SID_INFO_LENGTH)
+                       return bgp_attr_srv6_service_data(args);
+       }
+
+       /* Placeholder code for unsupported type */
+       else {
+               if (bgp_debug_update(peer, NULL, NULL, 1))
+                       zlog_debug(
+                               "%s attr SRv6 Service Sub-TLV sub-type=%u is not supported, skipped",
+                               peer->host, type);
+
+               stream_forward_getp(peer->curr, length);
+       }
+
+       return BGP_ATTR_PARSE_PROCEED;
+}
+
 /*
  * 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
@@ -2539,7 +2685,6 @@ static bgp_attr_parse_ret_t bgp_attr_psid_sub(uint8_t type, uint16_t length,
        uint32_t srgb_range;
        int srgb_count;
        uint8_t sid_type, sid_flags;
-       uint16_t endpoint_behavior;
        char buf[BUFSIZ];
 
        if (type == BGP_PREFIX_SID_LABEL_INDEX) {
@@ -2694,45 +2839,20 @@ static bgp_attr_parse_ret_t bgp_attr_psid_sub(uint8_t type, uint16_t length,
 
        /* Placeholder code for the SRv6 L3 Service type */
        else if (type == BGP_PREFIX_SID_SRV6_L3_SERVICE) {
-               if (STREAM_READABLE(peer->curr) < length
-                   || length != BGP_PREFIX_SID_SRV6_L3_SERVICE_LENGTH) {
-                       flog_err(EC_BGP_ATTR_LEN,
-                                "Prefix SID SRv6 L3-Service length is %hu instead of %u",
-                                length, BGP_PREFIX_SID_SRV6_L3_SERVICE_LENGTH);
+               if (STREAM_READABLE(peer->curr) < length) {
+                       flog_err(
+                               EC_BGP_ATTR_LEN,
+                               "Prefix SID SRv6 L3-Service length is %hu, but only %zu bytes remain",
+                               length, STREAM_READABLE(peer->curr));
                        return bgp_attr_malformed(args,
                                 BGP_NOTIFY_UPDATE_ATTR_LENG_ERR,
                                 args->total);
                }
 
-               /* Parse L3-SERVICE Sub-TLV */
-               stream_getc(peer->curr);               /* reserved  */
-               stream_get(&ipv6_sid, peer->curr,
-                          sizeof(ipv6_sid)); /* sid_value */
-               sid_flags = stream_getc(peer->curr);   /* sid_flags */
-               endpoint_behavior = stream_getw(peer->curr); /* endpoint */
-               stream_getc(peer->curr);               /* reserved  */
-
-               /* Log L3-SERVICE Sub-TLV */
-               if (BGP_DEBUG(vpn, VPN_LEAK_LABEL)) {
-                       inet_ntop(AF_INET6, &ipv6_sid, buf, sizeof(buf));
-                       zlog_debug(
-                               "%s: srv6-l3-srv sid %s, sid-flags 0x%02x, end-behaviour 0x%04x",
-                               __func__, buf, sid_flags, endpoint_behavior);
-               }
+               /* ignore reserved */
+               stream_getc(peer->curr);
 
-               /* Configure from Info */
-               if (attr->srv6_l3vpn) {
-                       flog_err(EC_BGP_ATTRIBUTE_REPEATED,
-                                "Prefix SID SRv6 L3VPN field repeated");
-                       return bgp_attr_malformed(
-                               args, BGP_NOTIFY_UPDATE_MAL_ATTR, args->total);
-               }
-               attr->srv6_l3vpn = XCALLOC(MTYPE_BGP_SRV6_L3VPN,
-                                          sizeof(struct bgp_attr_srv6_l3vpn));
-               attr->srv6_l3vpn->sid_flags = sid_flags;
-               attr->srv6_l3vpn->endpoint_behavior = endpoint_behavior;
-               sid_copy(&attr->srv6_l3vpn->sid, &ipv6_sid);
-               attr->srv6_l3vpn = srv6_l3vpn_intern(attr->srv6_l3vpn);
+               return bgp_attr_srv6_service(args);
        }
 
        /* Placeholder code for Unsupported TLV */

diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index d76b2d500513501f7341c0e714668df8ed6f4017..7eb1c8cf0e03f7d611078c193d543e5e03cd6477 100644 (file)
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -76,6 +76,9 @@
 #define BGP_PREFIX_SID_SRV6_L3_SERVICE_SID_INFO 1
 #define BGP_PREFIX_SID_SRV6_L3_SERVICE_SID_INFO_LENGTH 21
 
+/* SRv6 Service Data Sub-Sub-TLV types */
+#define BGP_PREFIX_SID_SRV6_L3_SERVICE_SID_STRUCTURE 1
+
 #define BGP_ATTR_NH_AFI(afi, attr) \
        ((afi != AFI_L2VPN) ? afi : \
        ((attr->mp_nexthop_len == BGP_ATTR_NHLEN_IPV4) ? AFI_IP : AFI_IP6))