diff options
| -rw-r--r-- | nest/attrs.h | 2 | ||||
| -rw-r--r-- | proto/bgp/attrs.c | 108 | ||||
| -rw-r--r-- | proto/bgp/bgp.c | 2 |
3 files changed, 95 insertions, 17 deletions
diff --git a/nest/attrs.h b/nest/attrs.h index 6f0bc1f..c12ce81 100644 --- a/nest/attrs.h +++ b/nest/attrs.h @@ -13,6 +13,8 @@ #define AS_PATH_SET 1 /* Types of path segments */ #define AS_PATH_SEQUENCE 2 +#define AS_PATH_CONFED_SEQUENCE 3 +#define AS_PATH_CONFED_SET 4 #define AS_PATH_MAXLEN 10000 diff --git a/proto/bgp/attrs.c b/proto/bgp/attrs.c index 91d4d06..b7c5f2e 100644 --- a/proto/bgp/attrs.c +++ b/proto/bgp/attrs.c @@ -77,16 +77,6 @@ bgp_check_as_path(struct bgp_proto *p, byte *a, int len) } static int -bgp_check_as4_path(struct bgp_proto *p, byte *a, int len) -{ - if (bgp_as4_support && (! p->as4_session)) - return bgp_check_path(a, len, 4, 9); - else - return 0; -} - - -static int bgp_check_next_hop(struct bgp_proto *p UNUSED, byte *a, int len) { #ifdef IPV6 @@ -196,8 +186,8 @@ static struct attr_desc bgp_attr_table[] = { bgp_check_unreach_nlri, NULL }, { NULL, }, /* BA_EXTENDED_COMM */ { "as4_path", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_AS4_PATH */ - bgp_check_as4_path, NULL }, - { "as4_aggregator", 8, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_AS4_PATH */ + NULL, NULL }, + { "as4_aggregator", -1, BAF_OPTIONAL | BAF_TRANSITIVE, EAF_TYPE_OPAQUE, 1, /* BA_AS4_PATH */ NULL, NULL } }; @@ -1063,6 +1053,85 @@ bgp_merge_as_paths(struct adata *old2, struct adata *old4, int req_as, struct li return newa; } +static int +as4_aggregator_valid(struct adata *aggr) +{ + if (aggr->length != 8) + return 0; + + u32 *a = (u32 *) aggr->data; + + if ((a[0] == 0) || (a[1] == 0)) + return 0; +} + +static int +as4_path_sanitize_and_get_length(struct adata *path) +{ + int res = 0; + u8 *p, *dst; + int len, plen, copy; + + dst = p = path->data; + len = path->length; + + while (len) + { + if (len <= 2) /* We do not allow empty segments */ + goto inconsistent_path; + + switch (p[0]) + { + case AS_PATH_SET: + plen = 2 + 4 * p[1]; + copy = 1; + res++; + break; + + case AS_PATH_SEQUENCE: + plen = 2 + 4 * p[1]; + copy = 1; + res += p[1]; + break; + + case AS_PATH_CONFED_SEQUENCE: + case AS_PATH_CONFED_SET: + log(L_WARN "BGP: AS4_PATH attribute contains AS_CONFED_* segment, skipping segment"); + plen = 2 + 4 * p[1]; + copy = 0; + break; + + default: + goto unknown_segment; + } + + if (len < plen) + goto inconsistent_path; + + if (copy) + { + if (dst != p) + memmove(dst, p, plen); + dst += plen; + } + + len -= plen; + p += plen; + } + + path->length = dst - path->data; + return res; + + inconsistent_path: + log(L_WARN "BGP: AS4_PATH attribute is inconsistent, skipping attribute"); + return -1; + + unknown_segment: + log(L_WARN "BGP: AS4_PATH attribute contains unknown segment, skipping attribute"); + return -1; +} + + /* Reconstruct 4B AS_PATH and AGGREGATOR according to RFC 4893 4.2.3 */ static void @@ -1072,6 +1141,14 @@ bgp_reconstruct_4b_atts(struct bgp_proto *p, rta *a, struct linpool *pool) eattr *p4 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS4_PATH)); eattr *a2 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AGGREGATOR)); eattr *a4 =ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_AS4_AGGREGATOR)); + int a4_removed = 0; + + if (a4 && !as4_aggregator_valid(a4->u.ptr)) + { + log(L_WARN "BGP: AS4_AGGREGATOR attribute is invalid, skipping attribute"); + a4 = NULL; + a4_removed = 1; + } if (a2) { @@ -1103,7 +1180,7 @@ bgp_reconstruct_4b_atts(struct bgp_proto *p, rta *a, struct linpool *pool) /* Common case, use old AGGREGATOR attribute */ a2->u.ptr = bgp_aggregator_convert_to_new(a2->u.ptr, pool); - if (a2_as == AS_TRANS) + if ((a2_as == AS_TRANS) && !a4_removed) log(L_WARN "BGP: AGGREGATOR attribute contain AS_TRANS, but AS4_AGGREGATOR is missing"); } } @@ -1112,13 +1189,12 @@ bgp_reconstruct_4b_atts(struct bgp_proto *p, rta *a, struct linpool *pool) log(L_WARN "BGP: AS4_AGGREGATOR attribute received, but AGGREGATOR attribute is missing"); int p2_len = as_path_getlen(p2->u.ptr); - int p4_len = p4 ? as_path_getlen(p4->u.ptr) : AS_PATH_MAXLEN; + int p4_len = p4 ? as4_path_sanitize_and_get_length(p4->u.ptr) : -1; - if (p2_len < p4_len) + if ((p4_len <= 0) || (p2_len < p4_len)) p2->u.ptr = bgp_merge_as_paths(p2->u.ptr, NULL, AS_PATH_MAXLEN, pool); else p2->u.ptr = bgp_merge_as_paths(p2->u.ptr, p4->u.ptr, p2_len - p4_len, pool); - } static void diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c index f44d016..41c8d53 100644 --- a/proto/bgp/bgp.c +++ b/proto/bgp/bgp.c @@ -53,7 +53,7 @@ * Unknown transitive attributes are attached to the route as %EAF_TYPE_OPAQUE byte streams. */ -#define LOCAL_DEBUG +#undef LOCAL_DEBUG #include "nest/bird.h" #include "nest/iface.h" |