diff options
| -rw-r--r-- | bgpd/bgp_aspath.c | 131 | ||||
| -rw-r--r-- | bgpd/bgp_aspath.h | 2 | ||||
| -rw-r--r-- | bgpd/bgp_attr.c | 100 |
3 files changed, 105 insertions, 128 deletions
diff --git a/bgpd/bgp_aspath.c b/bgpd/bgp_aspath.c index 5a73eeff..89a27531 100644 --- a/bgpd/bgp_aspath.c +++ b/bgpd/bgp_aspath.c @@ -671,78 +671,77 @@ aspath_hash_alloc (void *arg) return aspath; } -/* parse as-segment byte stream in struct assegment - * - * Returns NULL if the AS_PATH or AS4_PATH is not valid. - */ +/* parse as-segment byte stream in struct assegment */ static struct assegment * -assegments_parse (struct stream *s, size_t length, int use32bit, int as4_path) +assegments_parse (struct stream *s, size_t length, int use32bit) { struct assegment_header segh; struct assegment *seg, *prev = NULL, *head = NULL; + size_t bytes = 0; - assert (length > 0); /* does not expect empty AS_PATH or AS4_PATH */ + /* empty aspath (ie iBGP or somesuch) */ + if (length == 0) + return NULL; if (BGP_DEBUG (as4, AS4_SEGMENT)) zlog_debug ("[AS4SEG] Parse aspath segment: got total byte length %lu", (unsigned long) length); - - /* double check that length does not exceed stream */ - if (STREAM_READABLE(s) < length) + /* basic checks */ + if ((STREAM_READABLE(s) < length) + || (STREAM_READABLE(s) < AS_HEADER_SIZE) + || (length % AS16_VALUE_SIZE )) return NULL; - /* deal with each segment in turn */ - while (length > 0) + while (bytes < length) { int i; size_t seg_size; - /* softly softly, get the header first on its own */ - if (length >= AS_HEADER_SIZE) + if ((length - bytes) <= AS_HEADER_SIZE) { + if (head) + assegment_free_all (head); + return NULL; + } + + /* softly softly, get the header first on its own */ segh.type = stream_getc (s); segh.length = stream_getc (s); seg_size = ASSEGMENT_SIZE(segh.length, use32bit); - /* includes the header bytes */ if (BGP_DEBUG (as4, AS4_SEGMENT)) zlog_debug ("[AS4SEG] Parse aspath segment: got type %d, length %d", segh.type, segh.length); - switch (segh.type) - { - case AS_SEQUENCE: - case AS_SET: - break ; - - case AS_CONFED_SEQUENCE: - case AS_CONFED_SET: - if (!as4_path) - break ; - /* RFC4893 3: "invalid for the AS4_PATH attribute" */ - /* fall through */ - - default: /* reject unknown or invalid AS_PATH segment types */ - seg_size = 0 ; - } ; - } - else - seg_size = 0 ; - - /* Stop now if segment is not valid (discarding anything collected to date) - * - * RFC4271 4.3, Path Attributes, b) AS_PATH: - * - * "path segment value field contains one or more AS numbers" + /* check it.. */ + if ( ((bytes + seg_size) > length) + /* 1771bis 4.3b: seg length contains one or more */ + || (segh.length == 0) + /* Paranoia in case someone changes type of segment length. + * Shift both values by 0x10 to make the comparison operate + * on more, than 8 bits (otherwise it's a warning, bug #564). */ - if ((seg_size == 0) || (seg_size > length) || (segh.length == 0)) + || ((sizeof segh.length > 1) + && (0x10 + segh.length > 0x10 + AS_SEGMENT_MAX))) { + if (head) assegment_free_all (head); return NULL; } - length -= seg_size ; + switch (segh.type) + { + case AS_SEQUENCE: + case AS_SET: + case AS_CONFED_SEQUENCE: + case AS_CONFED_SET: + break; + default: + if (head) + assegment_free_all (head); + return NULL; + } /* now its safe to trust lengths */ seg = assegment_new (segh.type, segh.length); @@ -755,9 +754,11 @@ assegments_parse (struct stream *s, size_t length, int use32bit, int as4_path) for (i = 0; i < segh.length; i++) seg->as[i] = (use32bit) ? stream_getl (s) : stream_getw (s); + bytes += seg_size; + if (BGP_DEBUG (as4, AS4_SEGMENT)) - zlog_debug ("[AS4SEG] Parse aspath segment: length left: %lu", - (unsigned long) length); + zlog_debug ("[AS4SEG] Parse aspath segment: Bytes now: %lu", + (unsigned long) bytes); prev = seg; } @@ -765,42 +766,30 @@ assegments_parse (struct stream *s, size_t length, int use32bit, int as4_path) return assegment_normalise (head); } -/* AS path parse function -- parses AS_PATH and AS4_PATH attributes - * - * Requires: s -- stream, currently positioned before first segment - * of AS_PATH or AS4_PATH (ie after attribute header) - * length -- length of the value of the AS_PATH or AS4_PATH - * use32bit -- true <=> 4Byte ASN, otherwise 2Byte ASN - * as4_path -- true <=> AS4_PATH, otherwise AS_PATH - * - * Returns: if valid: address of struct aspath in the hash of known aspaths, - * with reference count incremented. - * else: NULL - * - * NB: empty AS path (length == 0) is valid. The returned struct aspath will - * have segments == NULL and str == zero length string (unique). - */ +/* AS path parse function. pnt is a pointer to byte stream and length + is length of byte stream. If there is same AS path in the the AS + path hash then return it else make new AS path structure. */ struct aspath * -aspath_parse (struct stream *s, size_t length, int use32bit, int as4_path) +aspath_parse (struct stream *s, size_t length, int use32bit) { struct aspath as; struct aspath *find; - /* Parse each segment and construct normalised list of struct assegment */ - memset (&as, 0, sizeof (struct aspath)); - if (length != 0) - { - as.segments = assegments_parse (s, length, use32bit, as4_path); + /* If length is odd it's malformed AS path. */ + /* Nit-picking: if (use32bit == 0) it is malformed if odd, + * otherwise its malformed when length is larger than 2 and (length-2) + * is not dividable by 4. + * But... this time we're lazy + */ + if (length % AS16_VALUE_SIZE ) + return NULL; - if (as.segments == NULL) - return NULL ; /* Invalid AS_PATH or AS4_PATH */ - } ; + memset (&as, 0, sizeof (struct aspath)); + as.segments = assegments_parse (s, length, use32bit); /* If already same aspath exist then return it. */ find = hash_get (ashash, &as, aspath_hash_alloc); - assert(find) ; /* valid aspath, so must find or create */ - /* aspath_hash_alloc dupes segments too. that probably could be * optimised out. */ @@ -808,6 +797,8 @@ aspath_parse (struct stream *s, size_t length, int use32bit, int as4_path) if (as.str) XFREE (MTYPE_AS_STR, as.str); + if (! find) + return NULL; find->refcnt++; return find; @@ -1631,7 +1622,7 @@ aspath_segment_add (struct aspath *as, int type) struct aspath * aspath_empty (void) { - return aspath_parse (NULL, 0, 1, 0); /* 32Bit ;-) not AS4_PATH */ + return aspath_parse (NULL, 0, 1); /* 32Bit ;-) */ } struct aspath * diff --git a/bgpd/bgp_aspath.h b/bgpd/bgp_aspath.h index d63b914c..b8a5dfab 100644 --- a/bgpd/bgp_aspath.h +++ b/bgpd/bgp_aspath.h @@ -65,7 +65,7 @@ struct aspath /* Prototypes. */ extern void aspath_init (void); extern void aspath_finish (void); -extern struct aspath *aspath_parse (struct stream *, size_t, int, int); +extern struct aspath *aspath_parse (struct stream *, size_t, int); extern struct aspath *aspath_dup (struct aspath *); extern struct aspath *aspath_aggregate (struct aspath *, struct aspath *); extern struct aspath *aspath_prepend (struct aspath *, struct aspath *); diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c index e2b6054b..7a0ab560 100644 --- a/bgpd/bgp_attr.c +++ b/bgpd/bgp_attr.c @@ -746,78 +746,51 @@ bgp_attr_origin (struct peer *peer, bgp_size_t length, return 0; } -/* Parse AS path information. This function is wrapper of aspath_parse. - * - * Parses AS_PATH or AS4_PATH. - * - * Returns: if valid: address of struct aspath in the hash of known aspaths, - * with reference count incremented. - * else: NULL - * - * NB: empty AS path (length == 0) is valid. The returned struct aspath will - * have segments == NULL and str == zero length string (unique). - */ -static struct aspath * + +/* Parse AS path information. This function is wrapper of + aspath_parse. */ +static int bgp_attr_aspath (struct peer *peer, bgp_size_t length, - struct attr *attr, u_char flag, u_char *startp, int as4_path) + struct attr *attr, u_char flag, u_char *startp) { - u_char require ; - struct aspath *asp ; + bgp_size_t total; - /* Check the attribute flags */ - require = as4_path ? BGP_ATTR_FLAG_OPTIONAL | BGP_ATTR_FLAG_TRANS - : BGP_ATTR_FLAG_TRANS ; + total = length + (CHECK_FLAG (flag, BGP_ATTR_FLAG_EXTLEN) ? 4 : 3); - if ((flag & (BGP_ATTR_FLAG_OPTIONAL | BGP_ATTR_FLAG_TRANS)) != require) + /* Flag check. */ + if (CHECK_FLAG (flag, BGP_ATTR_FLAG_OPTIONAL) + || ! CHECK_FLAG (flag, BGP_ATTR_FLAG_TRANS)) { - const char* path_type ; - bgp_size_t total; - - path_type = as4_path ? "AS4_PATH" : "AS_PATH" ; - - if (!CHECK_FLAG(flag, BGP_ATTR_FLAG_TRANS)) zlog (peer->log, LOG_ERR, - "%s attribute flag isn't transitive %d", path_type, flag) ; - - if ((flag & BGP_ATTR_FLAG_OPTIONAL) != (require & BGP_ATTR_FLAG_OPTIONAL)) - zlog (peer->log, LOG_ERR, - "%s attribute flag must %sbe optional %d", path_type, - (flag & BGP_ATTR_FLAG_OPTIONAL) ? "not " : "", flag) ; - - total = length + (CHECK_FLAG (flag, BGP_ATTR_FLAG_EXTLEN) ? 4 : 3); - + "As-Path attribute flag isn't transitive %d", flag); bgp_notify_send_with_data (peer, BGP_NOTIFY_UPDATE_ERR, BGP_NOTIFY_UPDATE_ATTR_FLAG_ERR, startp, total); + return -1; + } - return NULL ; - } ; - - /* Parse the AS_PATH/AS4_PATH body. - * - * For AS_PATH peer with AS4 => 4Byte ASN otherwise 2Byte ASN - * AS4_PATH 4Byte ASN + /* + * peer with AS4 => will get 4Byte ASnums + * otherwise, will get 16 Bit */ - asp = aspath_parse (peer->ibuf, length, - as4_path || CHECK_FLAG (peer->cap, PEER_CAP_AS4_RCV), as4_path) ; + attr->aspath = aspath_parse (peer->ibuf, length, + CHECK_FLAG (peer->cap, PEER_CAP_AS4_RCV)); - if (asp != NULL) - { - attr->flag |= ATTR_FLAG_BIT (as4_path ? BGP_ATTR_AS4_PATH - : BGP_ATTR_AS_PATH) ; - } - else + /* In case of IBGP, length will be zero. */ + if (! attr->aspath) { zlog (peer->log, LOG_ERR, "Malformed AS path length is %d", length); - - /* TODO: should BGP_NOTIFY_UPDATE_MAL_AS_PATH be sent for AS4_PATH ?? */ bgp_notify_send (peer, BGP_NOTIFY_UPDATE_ERR, BGP_NOTIFY_UPDATE_MAL_AS_PATH); - } ; + return -1; + } + + /* Set aspath attribute flag. */ + attr->flag |= ATTR_FLAG_BIT (BGP_ATTR_AS_PATH); - return asp ; + return 0; } static int bgp_attr_aspath_check( struct peer *peer, @@ -875,6 +848,21 @@ static int bgp_attr_aspath_check( struct peer *peer, } +/* Parse AS4 path information. This function is another wrapper of + aspath_parse. */ +static int +bgp_attr_as4_path (struct peer *peer, bgp_size_t length, + struct attr *attr, struct aspath **as4_path) +{ + *as4_path = aspath_parse (peer->ibuf, length, 1); + + /* Set aspath attribute flag. */ + if (as4_path) + attr->flag |= ATTR_FLAG_BIT (BGP_ATTR_AS4_PATH); + + return 0; +} + /* Nexthop attribute. */ static int bgp_attr_nexthop (struct peer *peer, bgp_size_t length, @@ -1613,12 +1601,10 @@ bgp_attr_parse (struct peer *peer, struct attr *attr, bgp_size_t size, ret = bgp_attr_origin (peer, length, attr, flag, startp); break; case BGP_ATTR_AS_PATH: - attr->aspath = bgp_attr_aspath (peer, length, attr, flag, startp, 0); - ret = attr->aspath ? 0 : -1 ; + ret = bgp_attr_aspath (peer, length, attr, flag, startp); break; case BGP_ATTR_AS4_PATH: - as4_path = bgp_attr_aspath (peer, length, attr, flag, startp, 1); - ret = as4_path ? 0 : -1 ; + ret = bgp_attr_as4_path (peer, length, attr, &as4_path ); break; case BGP_ATTR_NEXT_HOP: ret = bgp_attr_nexthop (peer, length, attr, flag, startp); |