On 2016/10/12 18:44, Job Snijders wrote:
> This patch adds support to tcpdump(8) to decode Large BGP
> Communities in human readable form.
>
> Example:
>
> [ snip ] BGP (UPDATE: (Path attributes: (ORIGIN[T] IGP)
> (AS_PATH[T] 65000)
> (NEXT_HOP[T] pxtr-2.meerval.net)
> (COMMUNITIES[OT] 666:666 2914:0)
> (LARGE_COMMUNITIES[OT] 2914:0:666 2914:4294927296:123))
> (NLRI: 9.9.9.10/32)) (DF) (ttl 63, id 2806, len 138)
>
> Kind regards,
>
> Job
OK sthen@.
>
> Index: src/usr.sbin/tcpdump/print-bgp.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/tcpdump/print-bgp.c,v
> retrieving revision 1.18
> diff -u -p -u -r1.18 print-bgp.c
> --- src/usr.sbin/tcpdump/print-bgp.c 20 Oct 2015 11:29:07 -0000 1.18
> +++ src/usr.sbin/tcpdump/print-bgp.c 12 Oct 2016 16:09:51 -0000
> @@ -134,6 +134,7 @@ struct bgp_attr {
> #define BGPTYPE_EXTD_COMMUNITIES 16 /* RFC4360 */
> #define BGPTYPE_AS4_PATH 17 /* RFC4893 */
> #define BGPTYPE_AGGREGATOR4 18 /* RFC4893 */
> +#define BGPTYPE_LARGE_COMMUNITIES 30 /*
> draft-ietf-idr-large-community */
>
> #define BGP_AS_SET 1
> #define BGP_AS_SEQUENCE 2
> @@ -265,7 +266,8 @@ static const char *bgpattr_type[] = {
> "MULTI_EXIT_DISC", "LOCAL_PREF", "ATOMIC_AGGREGATE", "AGGREGATOR",
> "COMMUNITIES", "ORIGINATOR_ID", "CLUSTER_LIST", "DPA",
> "ADVERTISERS", "RCID_PATH", "MP_REACH_NLRI", "MP_UNREACH_NLRI",
> - "EXTD_COMMUNITIES", "AS4_PATH", "AGGREGATOR4",
> + "EXTD_COMMUNITIES", "AS4_PATH", "AGGREGATOR4", NULL, NULL, NULL,
> + NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "LARGE_COMMUNITIES",
> };
> #define bgp_attr_type(x) \
> num_or_str(bgpattr_type, \
> @@ -544,6 +546,21 @@ bgp_attr_print(const struct bgp_attr *at
> }
> tlen -= 4;
> p += 4;
> + }
> + break;
> + case BGPTYPE_LARGE_COMMUNITIES:
> + if (len == 0 || len % 12) {
> + printf(" invalid len");
> + break;
> + }
> + while (tlen>0) {
> + TCHECK2(p[0], 12);
> + printf(" %u:%u:%u",
> + EXTRACT_32BITS(p),
> + EXTRACT_32BITS(p + 4),
> + EXTRACT_32BITS(p + 8));
> + tlen -= 12;
> + p += 12;
> }
> break;
> case BGPTYPE_ORIGINATOR_ID:
>
