/* packet-bgp.c * Routines for BGP packet dissection. * Copyright 1999, Jun-ichiro itojun Hagino * * $Id: packet-bgp.c,v 1.59 2002/05/21 21:55:46 guy Exp $ * * Supports: * RFC1771 A Border Gateway Protocol 4 (BGP-4) * RFC1965 Autonomous System Confederations for BGP * RFC1997 BGP Communities Attribute * RFC2547 BGP/MPLS VPNs * RFC2796 BGP Route Reflection An alternative to full mesh IBGP * RFC2842 Capabilities Advertisement with BGP-4 * RFC2858 Multiprotocol Extensions for BGP-4 * RFC2918 Route Refresh Capability for BGP-4 * RFC3107 Carrying Label Information in BGP-4 * Draft Ramahandra on Extended Communities Extentions * * TODO: * Destination Preference Attribute for BGP (work in progress) * RFC1863 A BGP/IDRP Route Server alternative to a full mesh routing * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #ifdef HAVE_SYS_TYPES_H # include #endif #ifdef HAVE_NETINET_IN_H # include #endif #ifdef HAVE_ARPA_INET_H #include #endif #include #include #ifdef NEED_SNPRINTF_H # include "snprintf.h" #endif #include #include "packet-bgp.h" #include "packet-ipv6.h" #include "afn.h" #include "prefs.h" static const value_string bgptypevals[] = { { BGP_OPEN, "OPEN Message" }, { BGP_UPDATE, "UPDATE Message" }, { BGP_NOTIFICATION, "NOTIFICATION Message" }, { BGP_KEEPALIVE, "KEEPALIVE Message" }, { BGP_ROUTE_REFRESH, "ROUTE-REFRESH Message" }, { BGP_ROUTE_REFRESH_CISCO, "Cisco ROUTE-REFRESH Message" }, { 0, NULL }, }; static const value_string bgpnotify_major[] = { { 1, "Message Header Error" }, { 2, "OPEN Message Error" }, { 3, "UPDATE Message Error" }, { 4, "Hold Timer Expired" }, { 5, "Finite State Machine Error" }, { 6, "Cease" }, { 0, NULL }, }; static const value_string bgpnotify_minor_1[] = { { 1, "Connection Not Synchronized" }, { 2, "Bad Message Length" }, { 3, "Bad Message Type" }, { 0, NULL }, }; static const value_string bgpnotify_minor_2[] = { { 1, "Unsupported Version Number" }, { 2, "Bad Peer AS" }, { 3, "Bad BGP Identifier" }, { 4, "Unsupported Optional Parameter" }, { 5, "Authentication Failure" }, { 6, "Unacceptable Hold Time" }, { 7, "Unsupported Capability" }, { 0, NULL }, }; static const value_string bgpnotify_minor_3[] = { { 1, "Malformed Attribute List" }, { 2, "Unrecognized Well-known Attribute" }, { 3, "Missing Well-known Attribute" }, { 4, "Attribute Flags Error" }, { 5, "Attribute Length Error" }, { 6, "Invalid ORIGIN Attribute" }, { 7, "AS Routing Loop" }, { 8, "Invalid NEXT_HOP Attribute" }, { 9, "Optional Attribute Error" }, { 10, "Invalid Network Field" }, { 11, "Malformed AS_PATH" }, { 0, NULL }, }; static const value_string *bgpnotify_minor[] = { NULL, bgpnotify_minor_1, bgpnotify_minor_2, bgpnotify_minor_3, }; static const value_string bgpattr_origin[] = { { 0, "IGP" }, { 1, "EGP" }, { 2, "INCOMPLETE" }, { 0, NULL }, }; static const value_string as_segment_type[] = { { 1, "AS_SET" }, { 2, "AS_SEQUENCE" }, /* RFC1965 has the wrong values, corrected in */ /* draft-ietf-idr-bgp-confed-rfc1965bis-01.txt */ { 4, "AS_CONFED_SET" }, { 3, "AS_CONFED_SEQUENCE" }, { 0, NULL }, }; static const value_string bgpattr_type[] = { { BGPTYPE_ORIGIN, "ORIGIN" }, { BGPTYPE_AS_PATH, "AS_PATH" }, { BGPTYPE_NEXT_HOP, "NEXT_HOP" }, { BGPTYPE_MULTI_EXIT_DISC, "MULTI_EXIT_DISC" }, { BGPTYPE_LOCAL_PREF, "LOCAL_PREF" }, { BGPTYPE_ATOMIC_AGGREGATE, "ATOMIC_AGGREGATE" }, { BGPTYPE_AGGREGATOR, "AGGREGATOR" }, { BGPTYPE_COMMUNITIES, "COMMUNITIES" }, { BGPTYPE_ORIGINATOR_ID, "ORIGINATOR_ID" }, { BGPTYPE_CLUSTER_LIST, "CLUSTER_LIST" }, { BGPTYPE_MP_REACH_NLRI, "MP_REACH_NLRI" }, { BGPTYPE_MP_UNREACH_NLRI, "MP_UNREACH_NLRI" }, { BGPTYPE_EXTENDED_COMMUNITY, "EXTENDED_COMMUNITIES" }, { 0, NULL }, }; /* Beware : See also MAX_SIZE_OF_EXT_COM_NAMES */ static const value_string bgpext_com_type[] = { { BGP_EXT_COM_RT_0, "Route Target" }, { BGP_EXT_COM_RT_1, "Route Target" }, { BGP_EXT_COM_RO_0, "Route Origin" }, { BGP_EXT_COM_RO_1, "Route Origin" }, { BGP_EXT_COM_LINKBAND, "Link Bandwidth" }, { BGP_EXT_COM_VPN_ORIGIN, "OSPF Domain" }, { BGP_EXT_COM_OSPF_RTYPE, "OSPF Route Type" }, { BGP_EXT_COM_OSPF_RID, "OSPF Router ID" }, { 0, NULL }, }; static const value_string bgpext_ospf_rtype[] = { { BGP_OSPF_RTYPE_RTR, "Router" }, { BGP_OSPF_RTYPE_NET, "Network" }, { BGP_OSPF_RTYPE_SUM, "Summary" }, { BGP_OSPF_RTYPE_EXT, "External" }, { BGP_OSPF_RTYPE_NSSA,"NSSA External" }, { BGP_OSPF_RTYPE_SHAM,"MPLS-VPN Sham" }, { 0, NULL }, }; /* MUST be resized if a longer named extended community is added */ #define MAX_SIZE_OF_EXT_COM_NAMES 20 /* Subsequent address family identifier, RFC2858 */ static const value_string bgpattr_nlri_safi[] = { { 0, "Reserved" }, { SAFNUM_UNICAST, "Unicast" }, { SAFNUM_MULCAST, "Multicast" }, { SAFNUM_UNIMULC, "Unicast+Multicast" }, { SAFNUM_MPLS_LABEL, "MPLS Labeled Prefix"}, { SAFNUM_LBVPNIP, "Labeled VPN-IPv4" }, /* draft-rosen-rfc2547bis-03 */ { 0, NULL }, }; /* ORF Type, draft-ietf-idr-route-filter-04.txt */ static const value_string orf_type_vals[] = { { 2, "Communities ORF-Type" }, { 3, "Extended Communities ORF-Type" }, { 0, NULL }, }; /* ORF Send/Receive, draft-ietf-idr-route-filter-04.txt */ static const value_string orf_send_recv_vals[] = { { 1, "Receive" }, { 2, "Send" }, { 3, "Both" }, { 0, NULL }, }; /* Maximal size of an IP address string */ #define MAX_SIZE_OF_IP_ADDR_STRING 16 static int proto_bgp = -1; static int hf_bgp_type = -1; static gint ett_bgp = -1; static gint ett_bgp_unfeas = -1; static gint ett_bgp_attrs = -1; static gint ett_bgp_attr = -1; static gint ett_bgp_attr_flags = -1; static gint ett_bgp_mp_nhna = -1; static gint ett_bgp_mp_reach_nlri = -1; static gint ett_bgp_mp_unreach_nlri = -1; static gint ett_bgp_mp_snpa = -1; static gint ett_bgp_nlri = -1; static gint ett_bgp_open = -1; static gint ett_bgp_update = -1; static gint ett_bgp_notification = -1; static gint ett_bgp_route_refresh = -1; /* ROUTE-REFRESH message tree */ static gint ett_bgp_as_paths = -1; static gint ett_bgp_communities = -1; static gint ett_bgp_cluster_list = -1; /* cluster list tree */ static gint ett_bgp_options = -1; /* optional parameters tree */ static gint ett_bgp_option = -1; /* an optional parameter tree */ static gint ett_bgp_extended_communities = -1 ; /* extended communities list tree */ /* desegmentation */ static gboolean bgp_desegment = TRUE; /* * Decode an IPv4 prefix. */ static int decode_prefix4(tvbuff_t *tvb, gint offset, char *buf, int buflen) { guint8 addr[4]; /* IP address */ int plen; /* prefix length */ int length; /* number of octets needed for prefix */ /* snarf length */ plen = tvb_get_guint8(tvb, offset); if (plen < 0 || 32 < plen) return -1; length = (plen + 7) / 8; /* snarf prefix */ memset(addr, 0, sizeof(addr)); tvb_memcpy(tvb, addr, offset + 1, length); if (plen % 8) addr[length - 1] &= ((0xff00 >> (plen % 8)) & 0xff); /* hand back a formatted string */ snprintf(buf, buflen, "%s/%d", ip_to_str(addr), plen); return(1 + length); } /* * Decode an IPv6 prefix. */ static int decode_prefix6(tvbuff_t *tvb, gint offset, char *buf, int buflen) { struct e_in6_addr addr; /* IPv6 address */ int plen; /* prefix length */ int length; /* number of octets needed for prefix */ /* snarf length */ plen = tvb_get_guint8(tvb, offset); if (plen < 0 || 128 < plen) return -1; length = (plen + 7) / 8; /* snarf prefix */ memset(&addr, 0, sizeof(addr)); tvb_memcpy(tvb, (guint8 *)&addr, offset + 1, length); if (plen % 8) addr.s6_addr[length - 1] &= ((0xff00 >> (plen % 8)) & 0xff); /* hand back a formatted string */ snprintf(buf, buflen, "%s/%d", ip6_to_str(&addr), plen); return(1 + length); } /* * Decode an MPLS label stack */ static int decode_MPLS_stack(tvbuff_t *tvb, gint offset, char *buf, size_t buflen) { guint32 label_entry; /* an MPLS label enrty (label + COS field + stack bit */ gint index; /* index for the label stack */ char junk_buf[256]; /* tmp */ index = offset ; label_entry = 0x000000 ; buf[0] = '\0' ; while ((label_entry & 0x000001) == 0) { label_entry = tvb_get_ntoh24(tvb, index) ; /* withdrawn routes may contain 0 or 0x800000 in the first label */ if((index-offset)==0&&(label_entry==0||label_entry==0x800000)) { snprintf(buf, buflen, "0 (withdrawn)"); return (1); } snprintf(junk_buf, sizeof(junk_buf),"%u%s", (label_entry >> 4), ((label_entry & 0x000001) == 0) ? "," : " (bottom)"); if (strlen(buf) + strlen(junk_buf) + 1 <= buflen) strcat(buf, junk_buf); index += 3 ; if ((label_entry & 0x000001) == 0) { /* real MPLS multi-label stack in BGP? - maybe later; for now, it must be a bogus packet */ strcpy(junk_buf, " (BOGUS: Bottom of Stack NOT set!)"); if (strlen(buf) + strlen(junk_buf) + 1 <= buflen) strcat(buf, junk_buf); break; } } return((index - offset) / 3); } /* * Decode a multiprotocol address */ static int mp_addr_to_str (guint16 afi, guint8 safi, tvbuff_t *tvb, gint offset, char *buf, int buflen) { int length; /* length of the address in byte */ guint8 ip4addr[4],ip4addr2[4]; /* IPv4 address */ guint16 rd_type; /* Route Distinguisher type */ struct e_in6_addr ip6addr; /* IPv6 address */ length = 0 ; switch (afi) { case AFNUM_INET: switch (safi) { case SAFNUM_UNICAST: case SAFNUM_MULCAST: case SAFNUM_UNIMULC: case SAFNUM_MPLS_LABEL: length = 4 ; tvb_memcpy(tvb, ip4addr, offset, 4); snprintf(buf, buflen, "%s", ip_to_str(ip4addr)); break; case SAFNUM_LBVPNIP: rd_type=tvb_get_ntohs(tvb,offset) ; switch (rd_type) { case FORMAT_AS2_LOC: length = 12; tvb_memcpy(tvb, ip4addr, offset + 8, 4); snprintf(buf, buflen, "Empty Label Stack RD=%u:%u IP=%s", tvb_get_ntohs(tvb, offset + 2), tvb_get_ntohl(tvb, offset + 4), ip_to_str(ip4addr)); break; case FORMAT_IP_LOC: length = 12; tvb_memcpy(tvb, ip4addr, offset + 2, 4); /* IP part of the RD */ tvb_memcpy(tvb, ip4addr2, offset +6, 4); /* IP address of the VPN-IPv4 */ snprintf(buf, buflen, "Empty Label Stack RD=%s:%u IP=%s", ip_to_str(ip4addr), tvb_get_ntohs(tvb, offset + 6), ip_to_str(ip4addr2)); break ; default: length = 0 ; snprintf(buf, buflen, "Unknown labeled VPN-IPv4 address format"); break; } break; default: length = 0 ; snprintf(buf, buflen, "Unknown SAFI value for AFI %u", afi); break; } break; case AFNUM_INET6: length = 16 ; tvb_memcpy(tvb, ip6addr.u6_addr.u6_addr8,offset, sizeof(ip6addr)); snprintf(buf, buflen, "%s", ip6_to_str(&ip6addr)); break; default: length = 0 ; snprintf(buf, buflen, "Unknown AFI value"); break; } return(length) ; } /* * Decode a multiprotocol prefix */ static int decode_prefix_MP(guint16 afi, guint8 safi, tvbuff_t *tvb, gint offset, char *buf, int buflen) { int length; /* length of the prefix in byte */ int plen; /* length of the prefix in bit */ int labnum; /* number of labels */ guint8 ip4addr[4],ip4addr2[4]; /* IPv4 address */ guint16 rd_type; /* Route Distinguisher type */ char lab_stk[256]; /* label stack */ length = 0 ; switch (afi) { case AFNUM_INET: switch (safi) { case SAFNUM_UNICAST: case SAFNUM_MULCAST: case SAFNUM_UNIMULC: length = decode_prefix4(tvb, offset, buf, buflen) - 1 ; break; case SAFNUM_MPLS_LABEL: plen = tvb_get_guint8(tvb,offset) ; labnum = decode_MPLS_stack(tvb, offset + 1, lab_stk, sizeof(lab_stk)); offset += (1 + labnum * 3); plen -= (labnum * 3*8); if (plen < 0 || 32 < plen) { length = 0 ; break ; } length = (plen + 7) / 8; memset(ip4addr, 0, sizeof(ip4addr)); tvb_memcpy(tvb, ip4addr, offset, length); if (plen % 8) ip4addr[length - 1] &= ((0xff00 >> (plen % 8)) & 0xff); snprintf(buf,buflen, "Label Stack=%s IP=%s/%d", lab_stk, ip_to_str(ip4addr), plen); length += (labnum*3) ; break; case SAFNUM_LBVPNIP: plen = tvb_get_guint8(tvb,offset) ; labnum = decode_MPLS_stack(tvb, offset + 1, lab_stk, sizeof(lab_stk)); offset += (1 + labnum * 3); plen -= (labnum * 3*8); rd_type=tvb_get_ntohs(tvb,offset) ; plen -= 8*8; switch (rd_type) { case FORMAT_AS2_LOC: /* Code borrowed from the decode_prefix4 function */ if (plen < 0 || 32 < plen) { length = 0 ; break ; } length = (plen + 7) / 8; memset(ip4addr, 0, sizeof(ip4addr)); tvb_memcpy(tvb, ip4addr, offset + 8, length); if (plen % 8) ip4addr[length - 1] &= ((0xff00 >> (plen % 8)) & 0xff); snprintf(buf,buflen, "Label Stack=%s RD=%u:%u, IP=%s/%d", lab_stk, tvb_get_ntohs(tvb, offset + 2), tvb_get_ntohl(tvb, offset + 4), ip_to_str(ip4addr), plen); length += (labnum * 3 + 8) ; break ; case FORMAT_IP_LOC: /* Code borrowed from the decode_prefix4 function */ tvb_memcpy(tvb, ip4addr, offset + 2, 4); if (plen < 0 || 32 < plen) { length = 0 ; break ; } length = (plen + 7) / 8; memset(ip4addr2, 0, sizeof(ip4addr2)); tvb_memcpy(tvb, ip4addr2, offset + 8, length); if (plen % 8) ip4addr2[length - 1] &= ((0xff00 >> (plen % 8)) & 0xff); snprintf(buf,buflen, "Label Stack=%s RD=%s:%u, IP=%s/%d", lab_stk, ip_to_str(ip4addr), tvb_get_ntohs(tvb, offset + 6), ip_to_str(ip4addr2), plen); length += (labnum * 3 + 8) ; break ; default: length = 0 ; snprintf(buf,buflen, "Unkown labeled VPN-IPv4 address format"); break; } break; default: length = 0 ; snprintf(buf,buflen, "Unkown SAFI value for AFI %u", afi); break; } break; case AFNUM_INET6: length = decode_prefix6(tvb, offset, buf, buflen) - 1 ; break; default: length = 0 ; snprintf(buf,buflen, "Unkown AFI value"); break; } return(1 + length) ; } /* * Dissect a BGP OPEN message. */ static const value_string community_vals[] = { { BGP_COMM_NO_EXPORT, "NO_EXPORT" }, { BGP_COMM_NO_ADVERTISE, "NO_ADVERTISE" }, { BGP_COMM_NO_EXPORT_SUBCONFED, "NO_EXPORT_SUBCONFED" }, { 0, NULL } }; static void dissect_bgp_open(tvbuff_t *tvb, int offset, proto_tree *tree) { struct bgp_open bgpo; /* BGP OPEN message */ int hlen; /* message length */ u_int i; /* tmp */ int ptype; /* parameter type */ int plen; /* parameter length */ int ctype; /* capability type */ int clen; /* capability length */ int cend; /* capabilities end */ int ostart; /* options start */ int oend; /* options end */ int p; /* tvb offset counter */ proto_item *ti; /* tree item */ proto_tree *subtree; /* subtree for options */ proto_tree *subtree1; /* subtree for an option */ proto_tree *subtree2; /* subtree for an option */ proto_tree *subtree3; /* subtree for an option */ guint8 orfnum; /* number of ORFs */ guint8 orftype; /* ORF Type */ guint8 orfsendrecv; /* ORF Send/Receive */ /* snarf OPEN message */ tvb_memcpy(tvb, bgpo.bgpo_marker, offset, BGP_MIN_OPEN_MSG_SIZE); hlen = ntohs(bgpo.bgpo_len); proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_open, bgpo_version), 1, "Version: %u", bgpo.bgpo_version); proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_open, bgpo_myas), 2, "My AS: %u", ntohs(bgpo.bgpo_myas)); proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_open, bgpo_holdtime), 2, "Hold time: %u", ntohs(bgpo.bgpo_holdtime)); proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_open, bgpo_id), 4, "BGP identifier: %s", ip_to_str((guint8 *)&bgpo.bgpo_id)); proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_open, bgpo_optlen), 1, "Optional parameters length: %u %s", bgpo.bgpo_optlen, (bgpo.bgpo_optlen == 1) ? "byte" : "bytes"); /* optional parameters */ if (bgpo.bgpo_optlen > 0) { /* add a subtree and setup some offsets */ ostart = offset + BGP_MIN_OPEN_MSG_SIZE; ti = proto_tree_add_text(tree, tvb, ostart, bgpo.bgpo_optlen, "Optional parameters"); subtree = proto_item_add_subtree(ti, ett_bgp_options); p = offset + ostart; oend = p + bgpo.bgpo_optlen; /* step through all of the optional parameters */ while (p < oend) { /* grab the type and length */ ptype = tvb_get_guint8(tvb, p++); plen = tvb_get_guint8(tvb, p++); /* check the type */ switch (ptype) { case BGP_OPTION_AUTHENTICATION: proto_tree_add_text(subtree, tvb, p - 2, 2 + plen, "Authentication information (%u %s)", plen, (plen == 1) ? "byte" : "bytes"); break; case BGP_OPTION_CAPABILITY: /* grab the capability code */ cend = p - 1 + plen; ctype = tvb_get_guint8(tvb, p++); clen = tvb_get_guint8(tvb, p++); ti = proto_tree_add_text(subtree, tvb, p - 4, 2 + plen, "Capabilities Advertisement (%u bytes)", 2 + plen); subtree1 = proto_item_add_subtree(ti, ett_bgp_option); proto_tree_add_text(subtree1, tvb, p - 4, 1, "Parameter type: Capabilities (2)"); proto_tree_add_text(subtree1, tvb, p - 3, 1, "Parameter length: %u %s", plen, (plen == 1) ? "byte" : "bytes"); p -= 2; /* step through all of the capabilities */ while (p < cend) { ctype = tvb_get_guint8(tvb, p++); clen = tvb_get_guint8(tvb, p++); /* check the capability type */ switch (ctype) { case BGP_CAPABILITY_RESERVED: ti = proto_tree_add_text(subtree1, tvb, p - 2, 2 + clen, "Reserved capability (%u %s)", 2 + clen, (clen == 1) ? "byte" : "bytes"); subtree2 = proto_item_add_subtree(ti, ett_bgp_option); proto_tree_add_text(subtree2, tvb, p - 2, 1, "Capability code: Reserved (0)"); proto_tree_add_text(subtree2, tvb, p - 1, 1, "Capability length: %u %s", clen, (clen == 1) ? "byte" : "bytes"); if (clen != 0) { proto_tree_add_text(subtree2, tvb, p, clen, "Capability value: Unknown"); } p += clen; break; case BGP_CAPABILITY_MULTIPROTOCOL: ti = proto_tree_add_text(subtree1, tvb, p - 2, 2 + clen, "Multiprotocol extensions capability (%u %s)", 2 + clen, (clen == 1) ? "byte" : "bytes"); subtree2 = proto_item_add_subtree(ti, ett_bgp_option); proto_tree_add_text(subtree2, tvb, p - 2, 1, "Capability code: Multiprotocol extensions (%d)", ctype); if (clen != 4) { proto_tree_add_text(subtree2, tvb, p - 1, 1, "Capability length: Invalid"); proto_tree_add_text(subtree2, tvb, p, clen, "Capability value: Unknown"); } else { proto_tree_add_text(subtree2, tvb, p - 1, 1, "Capability length: %u %s", clen, (clen == 1) ? "byte" : "bytes"); ti = proto_tree_add_text(subtree2, tvb, p, clen, "Capability value"); subtree3 = proto_item_add_subtree(ti, ett_bgp_option); /* AFI */ i = tvb_get_ntohs(tvb, p); proto_tree_add_text(subtree3, tvb, p, 2, "Address family identifier: %s (%u)", val_to_str(i, afn_vals, "Unknown"), i); p += 2; /* Reserved */ proto_tree_add_text(subtree3, tvb, p, 1, "Reserved: 1 byte"); p++; /* SAFI */ i = tvb_get_guint8(tvb, p); proto_tree_add_text(subtree3, tvb, p, 1, "Subsequent address family identifier: %s (%u)", val_to_str(i, bgpattr_nlri_safi, i >= 128 ? "Vendor specific" : "Unknown"), i); p++; } break; case BGP_CAPABILITY_ROUTE_REFRESH_CISCO: case BGP_CAPABILITY_ROUTE_REFRESH: ti = proto_tree_add_text(subtree1, tvb, p - 2, 2 + clen, "Route refresh capability (%u %s)", 2 + clen, (clen == 1) ? "byte" : "bytes"); subtree2 = proto_item_add_subtree(ti, ett_bgp_option); proto_tree_add_text(subtree2, tvb, p - 2, 1, "Capability code: Route refresh (%d)", ctype); if (clen != 0) { proto_tree_add_text(subtree2, tvb, p, clen, "Capability value: Invalid"); } else { proto_tree_add_text(subtree2, tvb, p - 1, 1, "Capability length: %u %s", clen, (clen == 1) ? "byte" : "bytes"); } p += clen; break; case BGP_CAPABILITY_COOPERATIVE_ROUTE_FILTERING: ti = proto_tree_add_text(subtree1, tvb, p - 2, 2 + clen, "Cooperative route filtering capability (%u %s)", 2 + clen, (clen == 1) ? "byte" : "bytes"); subtree2 = proto_item_add_subtree(ti, ett_bgp_option); proto_tree_add_text(subtree2, tvb, p - 2, 1, "Capability code: Cooperative route filtering (%d)", ctype); proto_tree_add_text(subtree2, tvb, p - 1, 1, "Capability length: %u %s", clen, (clen == 1) ? "byte" : "bytes"); ti = proto_tree_add_text(subtree2, tvb, p, clen, "Capability value"); subtree3 = proto_item_add_subtree(ti, ett_bgp_option); /* AFI */ i = tvb_get_ntohs(tvb, p); proto_tree_add_text(subtree3, tvb, p, 2, "Address family identifier: %s (%u)", val_to_str(i, afn_vals, "Unknown"), i); p += 2; /* Reserved */ proto_tree_add_text(subtree3, tvb, p, 1, "Reserved: 1 byte"); p++; /* SAFI */ i = tvb_get_guint8(tvb, p); proto_tree_add_text(subtree3, tvb, p, 1, "Subsequent address family identifier: %s (%u)", val_to_str(i, bgpattr_nlri_safi, i >= 128 ? "Vendor specific" : "Unknown"), i); p++; /* Number of ORFs */ orfnum = tvb_get_guint8(tvb, p); proto_tree_add_text(subtree3, tvb, p, 1, "Number of ORFs: %u", orfnum); p++; for (i=0; i= 128 ? "Private use" : "Unknown", ctype); proto_tree_add_text(subtree2, tvb, p - 1, 1, "Capability length: %u %s", clen, (clen == 1) ? "byte" : "bytes"); if (clen != 0) { proto_tree_add_text(subtree2, tvb, p, clen, "Capability value: Unknown"); } p += clen; break; } } break; default: proto_tree_add_text(subtree, tvb, p - 2, 2 + plen, "Unknown optional parameter"); break; } } } } /* * Dissect a BGP UPDATE message. */ static void dissect_bgp_update(tvbuff_t *tvb, int offset, proto_tree *tree) { struct bgp_attr bgpa; /* path attributes */ int hlen; /* message length */ gint o; /* packet offset */ gint q; /* tmp */ gint end; /* message end */ gint ext_com; /* EXTENDED COMMUNITY type */ int len; /* tmp */ int advance; /* tmp */ proto_item *ti; /* tree item */ proto_tree *subtree; /* subtree for attributes */ proto_tree *subtree2; /* subtree for attributes */ proto_tree *subtree3; /* subtree for attributes */ proto_tree *as_paths_tree; /* subtree for AS_PATHs */ proto_tree *as_path_tree; /* subtree for AS_PATH */ proto_tree *communities_tree; /* subtree for COMMUNITIES */ proto_tree *community_tree; /* subtree for a community */ proto_tree *cluster_list_tree; /* subtree for CLUSTER_LIST */ int i, j; /* tmp */ guint8 length; /* AS_PATH length */ guint8 type; /* AS_PATH type */ char *as_path_str = NULL; /* AS_PATH string */ char *communities_str = NULL; /* COMMUNITIES string */ char *cluster_list_str = NULL; /* CLUSTER_LIST string */ char *ext_com_str = NULL; /* EXTENDED COMMUNITY list */ char junk_buf[256]; /* tmp */ guint8 ipaddr[4]; /* IPv4 address */ hlen = tvb_get_ntohs(tvb, offset + BGP_MARKER_SIZE); o = offset + BGP_HEADER_SIZE; /* check for withdrawals */ len = tvb_get_ntohs(tvb, o); proto_tree_add_text(tree, tvb, o, 2, "Unfeasible routes length: %u %s", len, (len == 1) ? "byte" : "bytes"); o += 2; /* parse unfeasible prefixes */ if (len > 0) { ti = proto_tree_add_text(tree, tvb, o, len, "Withdrawn routes:"); subtree = proto_item_add_subtree(ti, ett_bgp_unfeas); /* parse each prefixes */ end = o + len; while (o < end) { i = decode_prefix4(tvb, o, junk_buf, sizeof(junk_buf)); proto_tree_add_text(subtree, tvb, o, i, "%s", junk_buf); o += i; } } else { o += len; } /* check for advertisements */ len = tvb_get_ntohs(tvb, o); proto_tree_add_text(tree, tvb, o, 2, "Total path attribute length: %u %s", len, (len == 1) ? "byte" : "bytes"); /* path attributes */ if (len > 0) { ti = proto_tree_add_text(tree, tvb, o + 2, len, "Path attributes"); subtree = proto_item_add_subtree(ti, ett_bgp_attrs); i = 2; while (i < len) { int alen, aoff; char *msg; guint16 af; guint8 saf; int off, snpa; int nexthop_len; tvb_memcpy(tvb, (guint8 *)&bgpa, o + i, sizeof(bgpa)); /* check for the Extended Length bit */ if (bgpa.bgpa_flags & BGP_ATTR_FLAG_EXTENDED_LENGTH) { alen = tvb_get_ntohs(tvb, o + i + sizeof(bgpa)); aoff = sizeof(bgpa) + 2; } else { alen = tvb_get_guint8(tvb, o + i + sizeof(bgpa)); aoff = sizeof(bgpa) + 1; } /* This is kind of ugly - similar code appears twice, but it helps browsing attrs. */ /* the first switch prints things in the title of the subtree */ switch (bgpa.bgpa_type) { case BGPTYPE_ORIGIN: if (alen != 1) goto default_attribute_top; msg = val_to_str(tvb_get_guint8(tvb, o + i + aoff), bgpattr_origin, "Unknown"); ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), msg, alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_AS_PATH: /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; /* must be freed by second switch! */ /* "alen * 6" (5 digits + space) should be a good estimate of how long the AS path string could be */ as_path_str = malloc((alen + 1) * 6); if (as_path_str == NULL) break; as_path_str[0] = '\0'; /* snarf each AS path */ while (q < end) { type = tvb_get_guint8(tvb, q++); if (type == AS_SET) { snprintf(as_path_str, 2, "{"); } else if (type == AS_CONFED_SET) { snprintf(as_path_str, 2, "["); } else if (type == AS_CONFED_SEQUENCE) { snprintf(as_path_str, 2, "("); } length = tvb_get_guint8(tvb, q++); /* snarf each value in path */ for (j = 0; j < length; j++) { snprintf(junk_buf, sizeof(junk_buf), "%u%s", tvb_get_ntohs(tvb, q), (type == AS_SET || type == AS_CONFED_SET) ? ", " : " "); strncat(as_path_str, junk_buf, sizeof(junk_buf)); q += 2; } /* cleanup end of string */ if (type == AS_SET) { as_path_str[strlen(as_path_str) - 2] = '}'; } else if (type == AS_CONFED_SET) { as_path_str[strlen(as_path_str) - 2] = ']'; } else if (type == AS_CONFED_SEQUENCE) { as_path_str[strlen(as_path_str) - 1] = ')'; } else { as_path_str[strlen(as_path_str) - 1] = '\0'; } } /* check for empty AS_PATH */ if (alen == 0) strncpy(as_path_str, "empty", 6); ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), as_path_str, alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_NEXT_HOP: if (alen != 4) goto default_attribute_top; tvb_memcpy(tvb, ipaddr, o + i + aoff, 4); ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), ip_to_str(ipaddr), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_MULTI_EXIT_DISC: if (alen != 4) goto default_attribute_top; ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %u (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), tvb_get_ntohl(tvb, o + i + aoff), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_LOCAL_PREF: if (alen != 4) goto default_attribute_top; ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %u (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), tvb_get_ntohl(tvb, o + i + aoff), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_ATOMIC_AGGREGATE: if (alen != 0) goto default_attribute_top; ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_AGGREGATOR: if (alen != 6) goto default_attribute_top; tvb_memcpy(tvb, ipaddr, o + i + aoff + 2, 4); ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: AS: %u origin: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), tvb_get_ntohs(tvb, o + i + aoff), ip_to_str(ipaddr), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_COMMUNITIES: if (alen % 4 != 0) goto default_attribute_top; /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; /* must be freed by second switch! */ /* "alen * 12" (5 digits, a :, 5 digits + space ) should be a good estimate of how long the communities string could be */ communities_str = malloc((alen + 1) * 12); if (communities_str == NULL) break; communities_str[0] = '\0'; memset(junk_buf, 0, sizeof(junk_buf)); /* snarf each community */ while (q < end) { /* check for well-known communities */ if (tvb_get_ntohl(tvb, q) == BGP_COMM_NO_EXPORT) strncpy(junk_buf, "NO_EXPORT ", 10); else if (tvb_get_ntohl(tvb, q) == BGP_COMM_NO_ADVERTISE) strncpy(junk_buf, "NO_ADVERTISE ", 13); else if (tvb_get_ntohl(tvb, q) == BGP_COMM_NO_EXPORT_SUBCONFED) strncpy(junk_buf, "NO_EXPORT_SUBCONFED ", 20); else { snprintf(junk_buf, sizeof(junk_buf), "%u:%u ", tvb_get_ntohs(tvb, q), tvb_get_ntohs(tvb, q + 2)); } q += 4; strncat(communities_str, junk_buf, sizeof(junk_buf)); } /* cleanup end of string */ communities_str[strlen(communities_str) - 1] = '\0'; ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), communities_str, alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_ORIGINATOR_ID: if (alen != 4) goto default_attribute_top; tvb_memcpy(tvb, ipaddr, o + i + aoff, 4); ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), ip_to_str(ipaddr), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_CLUSTER_LIST: if (alen % 4 != 0) goto default_attribute_top; /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; /* must be freed by second switch! */ /* "alen * 16" (12 digits, 3 dots + space ) should be a good estimate of how long the cluster_list string could be */ cluster_list_str = malloc((alen + 1) * 16); if (cluster_list_str == NULL) break; cluster_list_str[0] = '\0'; memset(junk_buf, 0, sizeof(junk_buf)); /* snarf each cluster list */ tvb_memcpy(tvb, ipaddr, q, 4); while (q < end) { snprintf(junk_buf, sizeof(junk_buf), "%s ", ip_to_str(ipaddr)); strncat(cluster_list_str, junk_buf, sizeof(junk_buf)); q += 4; } /* cleanup end of string */ cluster_list_str[strlen(cluster_list_str) - 1] = '\0'; ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), cluster_list_str, alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); break; case BGPTYPE_EXTENDED_COMMUNITY: if (alen %8 != 0) goto default_attribute_top; /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; ext_com_str = malloc((alen / 8)*MAX_SIZE_OF_EXT_COM_NAMES); if (ext_com_str == NULL) break; ext_com_str[0] = '\0'; while (q < end) { ext_com = tvb_get_ntohs(tvb, q); snprintf(junk_buf, sizeof(junk_buf), "%s", val_to_str(ext_com,bgpext_com_type,"Unknown")); strncat(ext_com_str, junk_buf, sizeof(junk_buf)); q = q + 8; if (q < end) strncat(ext_com_str, ",", 1); } ti = proto_tree_add_text(subtree,tvb,o+i,alen+aoff, "%s: %s (%u %s)", val_to_str(bgpa.bgpa_type,bgpattr_type,"Unknown"), ext_com_str, alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); free(ext_com_str); break; default: default_attribute_top: ti = proto_tree_add_text(subtree, tvb, o + i, alen + aoff, "%s (%u %s)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), alen + aoff, (alen + aoff == 1) ? "byte" : "bytes"); } /* end of first switch */ subtree2 = proto_item_add_subtree(ti, ett_bgp_attr); /* figure out flags */ junk_buf[0] = '\0'; if (bgpa.bgpa_flags & BGP_ATTR_FLAG_OPTIONAL) { strncat(junk_buf, "Optional, ", 10); } else { strncat(junk_buf, "Well-known, ", 12); } if (bgpa.bgpa_flags & BGP_ATTR_FLAG_TRANSITIVE) { strncat(junk_buf, "Transitive, ", 12); } else { strncat(junk_buf, "Non-transitive, ", 16); } if (bgpa.bgpa_flags & BGP_ATTR_FLAG_PARTIAL) { strncat(junk_buf, "Partial, ", 9); } else { strncat(junk_buf, "Complete, ", 10); } if (bgpa.bgpa_flags & BGP_ATTR_FLAG_EXTENDED_LENGTH) { strncat(junk_buf, "Extended Length, ", 17); } /* stomp last ", " */ j = strlen(junk_buf); junk_buf[j - 2] = '\0'; ti = proto_tree_add_text(subtree2, tvb, o + i + offsetof(struct bgp_attr, bgpa_flags), 1, "Flags: 0x%02x (%s)", bgpa.bgpa_flags, junk_buf); subtree3 = proto_item_add_subtree(ti, ett_bgp_attr_flags); /* add flag bitfield subtrees */ proto_tree_add_text(subtree3, tvb, o + i + offsetof(struct bgp_attr, bgpa_flags), 1, "%s", decode_boolean_bitfield(bgpa.bgpa_flags, BGP_ATTR_FLAG_OPTIONAL, 8, "Optional", "Well-known")); proto_tree_add_text(subtree3, tvb, o + i + offsetof(struct bgp_attr, bgpa_flags), 1, "%s", decode_boolean_bitfield(bgpa.bgpa_flags, BGP_ATTR_FLAG_TRANSITIVE, 8, "Transitive", "Non-transitive")); proto_tree_add_text(subtree3, tvb, o + i + offsetof(struct bgp_attr, bgpa_flags), 1, "%s", decode_boolean_bitfield(bgpa.bgpa_flags, BGP_ATTR_FLAG_PARTIAL, 8, "Partial", "Complete")); proto_tree_add_text(subtree3, tvb, o + i + offsetof(struct bgp_attr, bgpa_flags), 1, "%s", decode_boolean_bitfield(bgpa.bgpa_flags, BGP_ATTR_FLAG_EXTENDED_LENGTH, 8, "Extended length", "Regular length")); proto_tree_add_text(subtree2, tvb, o + i + offsetof(struct bgp_attr, bgpa_type), 1, "Type code: %s (%u)", val_to_str(bgpa.bgpa_type, bgpattr_type, "Unknown"), bgpa.bgpa_type); proto_tree_add_text(subtree2, tvb, o + i + sizeof(bgpa), aoff - sizeof(bgpa), "Length: %d %s", alen, (alen == 1) ? "byte" : "bytes"); /* the second switch prints things in the actual subtree of each attribute */ switch (bgpa.bgpa_type) { case BGPTYPE_ORIGIN: if (alen != 1) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Origin (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } else { msg = val_to_str(tvb_get_guint8(tvb, o + i + aoff), bgpattr_origin, "Unknown"); proto_tree_add_text(subtree2, tvb, o + i + aoff, 1, "Origin: %s (%u)", msg, tvb_get_guint8(tvb, o + i + aoff)); } break; case BGPTYPE_AS_PATH: /* check for empty AS_PATH */ if (alen == 0) { free(as_path_str); break; } ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "AS path: %s", as_path_str); as_paths_tree = proto_item_add_subtree(ti, ett_bgp_as_paths); /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; /* snarf each AS path tuple, we have to step through each one again to make a separate subtree so we can't just reuse as_path_str from above */ while (q < end) { as_path_str[0] = '\0'; type = tvb_get_guint8(tvb, q++); if (type == AS_SET) { snprintf(as_path_str, 2, "{"); } else if (type == AS_CONFED_SET) { snprintf(as_path_str, 2, "["); } else if (type == AS_CONFED_SEQUENCE) { snprintf(as_path_str, 2, "("); } length = tvb_get_guint8(tvb, q++); /* snarf each value in path, we're just going to reuse as_path_str since we already have it malloced */ for (j = 0; j < length; j++) { snprintf(junk_buf, sizeof(junk_buf), "%u%s", tvb_get_ntohs(tvb, q), (type == AS_SET || type == AS_CONFED_SET) ? ", " : " "); strncat(as_path_str, junk_buf, sizeof(junk_buf)); q += 2; } /* cleanup end of string */ if (type == AS_SET) { as_path_str[strlen(as_path_str) - 2] = '}'; } else if (type == AS_CONFED_SET) { as_path_str[strlen(as_path_str) - 2] = ']'; } else if (type == AS_CONFED_SEQUENCE) { as_path_str[strlen(as_path_str) - 1] = ')'; } else { as_path_str[strlen(as_path_str) - 1] = '\0'; } /* length here means number of ASs, ie length * 2 bytes */ ti = proto_tree_add_text(as_paths_tree, tvb, q - length * 2 - 2, length * 2 + 2, "AS path segment: %s", as_path_str); as_path_tree = proto_item_add_subtree(ti, ett_bgp_as_paths); proto_tree_add_text(as_path_tree, tvb, q - length * 2 - 2, 1, "Path segment type: %s (%u)", val_to_str(type, as_segment_type, "Unknown"), type); proto_tree_add_text(as_path_tree, tvb, q - length * 2 - 1, 1, "Path segment length: %u %s", length, (length == 1) ? "AS" : "ASs"); /* backup and reprint path segment value(s) only */ q -= 2 * length; as_path_str[0] = '\0'; for (j = 0; j < length; j++) { snprintf(junk_buf, sizeof(junk_buf), "%u ", tvb_get_ntohs(tvb, q)); strncat(as_path_str, junk_buf, sizeof(junk_buf)); q += 2; } as_path_str[strlen(as_path_str) - 1] = '\0'; proto_tree_add_text(as_path_tree, tvb, q - length * 2, length * 2, "Path segment value: %s", as_path_str); } free(as_path_str); break; case BGPTYPE_NEXT_HOP: if (alen != 4) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Next hop (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } else { tvb_memcpy(tvb, ipaddr, o + i + aoff, 4); proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Next hop: %s", ip_to_str(ipaddr)); } break; case BGPTYPE_MULTI_EXIT_DISC: if (alen != 4) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Multiple exit discriminator (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } else { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Multiple exit discriminator: %u", tvb_get_ntohl(tvb, o + i + aoff)); } break; case BGPTYPE_LOCAL_PREF: if (alen != 4) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Local preference (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } else { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Local preference: %u", tvb_get_ntohl(tvb, o + i + aoff)); } break; case BGPTYPE_ATOMIC_AGGREGATE: if (alen != 0) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Atomic aggregate (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } break; case BGPTYPE_AGGREGATOR: if (alen != 6) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Aggregator (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } else { proto_tree_add_text(subtree2, tvb, o + i + aoff, 2, "Aggregator AS: %u", tvb_get_ntohs(tvb, o + i + aoff)); tvb_memcpy(tvb, ipaddr, o + i + aoff + 2, 4); proto_tree_add_text(subtree2, tvb, o + i + aoff + 2, 4, "Aggregator origin: %s", ip_to_str(ipaddr)); } break; case BGPTYPE_COMMUNITIES: if (alen % 4 != 0) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Communities (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); free(communities_str); break; } ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Communities: %s", communities_str); communities_tree = proto_item_add_subtree(ti, ett_bgp_communities); /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; /* snarf each community */ while (q < end) { /* check for reserved values */ guint32 community = tvb_get_ntohl(tvb, q); if ((community & 0xFFFF0000) == FOURHEX0 || (community & 0xFFFF0000) == FOURHEXF) { proto_tree_add_text(communities_tree, tvb, q - 3 + aoff, 4, "Community: %s (0x%08x)", val_to_str(community, community_vals, "(reserved)"), community); } else { ti = proto_tree_add_text(communities_tree, tvb, q - 3 + aoff, 4, "Community: %u:%u", tvb_get_ntohs(tvb, q), tvb_get_ntohs(tvb, q + 2)); community_tree = proto_item_add_subtree(ti, ett_bgp_communities); proto_tree_add_text(community_tree, tvb, q - 3 + aoff, 2, "Community AS: %u", tvb_get_ntohs(tvb, q)); proto_tree_add_text(community_tree, tvb, q - 1 + aoff, 2, "Community value: %u", tvb_get_ntohs(tvb, q + 2)); } q += 4; } free(communities_str); break; case BGPTYPE_ORIGINATOR_ID: if (alen != 4) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Originator identifier (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); } else { tvb_memcpy(tvb, ipaddr, o + i + aoff, 4); proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Originator identifier: %s", ip_to_str(ipaddr)); } break; case BGPTYPE_MP_REACH_NLRI: /* * RFC 2545 specifies that there may be more than one * address in the MP_REACH_NLRI attribute in section * 3, "Constructing the Next Hop field". * * Yes, RFC 2858 says you can't do that, and, yes, RFC * 2858 obsoletes RFC 2283, which says you can do that, * but that doesn't mean we shouldn't dissect packets * that conform to RFC 2283 but not RFC 2858, as some * device on the network might implement the 2283-style * BGP extensions rather than RFC 2858-style extensions. */ af = tvb_get_ntohs(tvb, o + i + aoff); proto_tree_add_text(subtree2, tvb, o + i + aoff, 2, "Address family: %s (%u)", val_to_str(af, afn_vals, "Unknown"), af); saf = tvb_get_guint8(tvb, o + i + aoff + 2) ; proto_tree_add_text(subtree2, tvb, o + i + aoff + 2, 1, "Subsequent address family identifier: %s (%u)", val_to_str(saf, bgpattr_nlri_safi, saf >= 128 ? "Vendor specific" : "Unknown"), saf); nexthop_len = tvb_get_guint8(tvb, o + i + aoff + 3); ti = proto_tree_add_text(subtree2, tvb, o + i + aoff + 3, 1, "Next hop network address (%d %s)", nexthop_len, plurality(nexthop_len, "byte", "bytes")); subtree3 = proto_item_add_subtree(ti, ett_bgp_mp_nhna); j = 0; while (j < nexthop_len) { advance = mp_addr_to_str(af, saf, tvb, o + i + aoff + 4 + j, junk_buf, sizeof(junk_buf)) ; if (j + advance > nexthop_len) break; proto_tree_add_text(subtree3, tvb,o + i + aoff + 4 + j, advance, "Next hop: %s (%u)", junk_buf, advance); j += advance; } alen -= nexthop_len + 4; aoff += nexthop_len + 4 ; off = 0; snpa = tvb_get_guint8(tvb, o + i + aoff); ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, 1, "Subnetwork points of attachment: %u", snpa); off++; if (snpa) { subtree3 = proto_item_add_subtree(ti, ett_bgp_mp_snpa); for (/*nothing*/; snpa > 0; snpa--) { proto_tree_add_text(subtree3, tvb, o + i + aoff + off, 1, "SNPA length: %u", tvb_get_guint8(tvb, o + i + aoff + off)); off++; proto_tree_add_text(subtree3, tvb, o + i + aoff + off, tvb_get_guint8(tvb, o + i + aoff + off - 1), "SNPA (%u %s)", tvb_get_guint8(tvb, o + i + aoff + off - 1), (tvb_get_guint8(tvb, o + i + aoff + off - 1) == 1) ? "byte" : "bytes"); off += tvb_get_guint8(tvb, o + i + aoff + off - 1); } } alen -= off; aoff += off; ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Network layer reachability information (%u %s)", alen, (alen == 1) ? "byte" : "bytes"); if (alen) { subtree3 = proto_item_add_subtree(ti,ett_bgp_mp_reach_nlri); while (alen > 0) { advance = decode_prefix_MP(af, saf, tvb, o + i + aoff , junk_buf, sizeof(junk_buf)) ; proto_tree_add_text(subtree3, tvb, o + i + aoff, advance, "%s", junk_buf) ; alen -= advance; aoff += advance; } } break; case BGPTYPE_MP_UNREACH_NLRI: af = tvb_get_ntohs(tvb, o + i + aoff); proto_tree_add_text(subtree2, tvb, o + i + aoff, 2, "Address family: %s (%u)", val_to_str(af, afn_vals, "Unknown"), af); saf = tvb_get_guint8(tvb, o + i + aoff + 2) ; proto_tree_add_text(subtree2, tvb, o + i + aoff + 2, 1, "Subsequent address family identifier: %s (%u)", val_to_str(saf, bgpattr_nlri_safi, saf >= 128 ? "Vendor specific" : "Unknown"), saf); ti = proto_tree_add_text(subtree2, tvb, o + i + aoff + 3, alen - 3, "Withdrawn routes (%u %s)", alen - 3, (alen - 3 == 1) ? "byte" : "bytes"); alen -= 3; aoff += 3; if (alen > 0) { subtree3 = proto_item_add_subtree(ti,ett_bgp_mp_unreach_nlri); while (alen > 0) { advance = decode_prefix_MP(af, saf, tvb, o + i + aoff , junk_buf, sizeof(junk_buf)) ; proto_tree_add_text(subtree3, tvb, o + i + aoff, advance, "%s", junk_buf) ; alen -= advance; aoff += advance; } } break; case BGPTYPE_CLUSTER_LIST: if (alen % 4 != 0) { proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Cluster list (invalid): %u %s", alen, (alen == 1) ? "byte" : "bytes"); free(cluster_list_str); break; } ti = proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Cluster list: %s", cluster_list_str); cluster_list_tree = proto_item_add_subtree(ti, ett_bgp_cluster_list); /* (o + i + aoff) = (o + current attribute + aoff bytes to first tuple) */ q = o + i + aoff; end = q + alen; /* snarf each cluster identifier */ while (q < end) { tvb_memcpy(tvb, ipaddr, q, 4); ti = proto_tree_add_text(cluster_list_tree, tvb, q - 3 + aoff, 4, "Cluster identifier: %s", ip_to_str(ipaddr)); q += 4; } free(cluster_list_str); break; case BGPTYPE_EXTENDED_COMMUNITY: if (alen %8 != 0) { proto_tree_add_text(subtree3, tvb, o + i + aoff, alen, "Extended community (invalid) : %u %s", alen, (alen == 1) ? "byte" : "bytes") ; } else { q = o + i + aoff ; end = o + i + aoff + alen ; ext_com_str = malloc(MAX_SIZE_OF_EXT_COM_NAMES+MAX_SIZE_OF_IP_ADDR_STRING*2+1) ; if (ext_com_str == NULL) break ; ti = proto_tree_add_text(subtree2,tvb,q,alen, "Carried Extended communities"); subtree3 = proto_item_add_subtree(ti,ett_bgp_extended_communities) ; while (q < end) { ext_com_str[0] = '\0' ; ext_com = tvb_get_ntohs(tvb,q) ; snprintf(junk_buf, sizeof(junk_buf), "%s", val_to_str(ext_com,bgpext_com_type,"Unknown")); strncat(ext_com_str,junk_buf,sizeof(junk_buf)); switch (ext_com) { case BGP_EXT_COM_RT_0: case BGP_EXT_COM_RO_0: snprintf(junk_buf, sizeof(junk_buf), ": %u%s%d",tvb_get_ntohs(tvb,q+2),":",tvb_get_ntohl(tvb,q+4)); break ; case BGP_EXT_COM_RT_1: case BGP_EXT_COM_RO_1: tvb_memcpy(tvb,ipaddr,q+2,4); snprintf(junk_buf, sizeof(junk_buf), ": %s%s%u",ip_to_str(ipaddr),":",tvb_get_ntohs(tvb,q+6)); break; case BGP_EXT_COM_VPN_ORIGIN: case BGP_EXT_COM_OSPF_RID: tvb_memcpy(tvb,ipaddr,q+2,4); snprintf(junk_buf, sizeof(junk_buf), ": %s",ip_to_str(ipaddr)); break; case BGP_EXT_COM_OSPF_RTYPE: tvb_memcpy(tvb,ipaddr,q+2,4); snprintf(junk_buf, sizeof(junk_buf), ": Area:%s %s",ip_to_str(ipaddr),val_to_str(tvb_get_guint8(tvb,q+6),bgpext_ospf_rtype,"Unknown")); /* print OSPF Metric type if selected */ /* always print E2 even if not external route -- receiving router should ignore */ if ( (tvb_get_guint8(tvb,q+7)) & BGP_OSPF_RTYPE_METRIC_TYPE ) { strcat(junk_buf," E2"); } else if (tvb_get_guint8(tvb,q+6)==(BGP_OSPF_RTYPE_EXT ||BGP_OSPF_RTYPE_NSSA ) ) { strcat(junk_buf, " E1"); } break; case BGP_EXT_COM_LINKBAND: tvb_memcpy(tvb,ipaddr,q+2,4); /* need to check on IEEE format on all platforms */ snprintf(junk_buf, sizeof(junk_buf), ": %f bytes per second",(double)*ipaddr); break; default: snprintf(junk_buf, sizeof(junk_buf), " "); break ; } strncat(ext_com_str,junk_buf,sizeof(junk_buf)); proto_tree_add_text(subtree3,tvb,q,8, "%s",ext_com_str); q = q + 8 ; } free(ext_com_str) ; } break; default: proto_tree_add_text(subtree2, tvb, o + i + aoff, alen, "Unknown (%d %s)", alen, (alen == 1) ? "byte" : "bytes"); break; } /* end of second switch */ i += alen + aoff; } o += 2 + len; /* NLRI */ len = offset + hlen - o; /* parse prefixes */ if (len > 0) { ti = proto_tree_add_text(tree, tvb, o, len, "Network layer reachability information: %u %s", len, (len == 1) ? "byte" : "bytes"); subtree = proto_item_add_subtree(ti, ett_bgp_nlri); end = o + len; while (o < end) { i = decode_prefix4(tvb, o, junk_buf, sizeof(junk_buf)); proto_tree_add_text(subtree, tvb, o, i, "%s", junk_buf); o += i; } } } } /* * Dissect a BGP NOTIFICATION message. */ static void dissect_bgp_notification(tvbuff_t *tvb, int offset, proto_tree *tree) { struct bgp_notification bgpn; /* BGP NOTIFICATION message */ int hlen; /* message length */ char *p; /* string pointer */ /* snarf message */ tvb_memcpy(tvb, bgpn.bgpn_marker, offset, BGP_MIN_NOTIFICATION_MSG_SIZE); hlen = ntohs(bgpn.bgpn_len); /* print error code */ proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_notification, bgpn_major), 1, "Error code: %s (%u)", val_to_str(bgpn.bgpn_major, bgpnotify_major, "Unknown"), bgpn.bgpn_major); /* print error subcode */ if (bgpn.bgpn_major < array_length(bgpnotify_minor) && bgpnotify_minor[bgpn.bgpn_major] != NULL) { p = val_to_str(bgpn.bgpn_minor, bgpnotify_minor[bgpn.bgpn_major], "Unknown"); } else if (bgpn.bgpn_minor == 0) p = "Unspecified"; else p = "Unknown"; proto_tree_add_text(tree, tvb, offset + offsetof(struct bgp_notification, bgpn_minor), 1, "Error subcode: %s (%u)", p, bgpn.bgpn_minor); /* only print if there is optional data */ if (hlen > BGP_MIN_NOTIFICATION_MSG_SIZE) { proto_tree_add_text(tree, tvb, offset + BGP_MIN_NOTIFICATION_MSG_SIZE, hlen - BGP_MIN_NOTIFICATION_MSG_SIZE, "Data"); } } /* * Dissect a BGP ROUTE-REFRESH message. */ static void dissect_bgp_route_refresh(tvbuff_t *tvb, int offset, proto_tree *tree) { u_int i; /* tmp */ /* AFI */ i = tvb_get_ntohs(tvb, offset + BGP_HEADER_SIZE); proto_tree_add_text(tree, tvb, offset + BGP_HEADER_SIZE, 2, "Address family identifier: %s (%u)", val_to_str(i, afn_vals, "Unknown"), i); offset += 2; /* Reserved */ proto_tree_add_text(tree, tvb, offset + BGP_HEADER_SIZE, 1, "Reserved: 1 byte"); offset++; /* SAFI */ i = tvb_get_guint8(tvb, offset + BGP_HEADER_SIZE); proto_tree_add_text(tree, tvb, offset + BGP_HEADER_SIZE, 1, "Subsequent address family identifier: %s (%u)", val_to_str(i, bgpattr_nlri_safi, i >= 128 ? "Vendor specific" : "Unknown"), i); } /* * Dissect a BGP packet. */ static void dissect_bgp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *ti; /* tree item */ proto_tree *bgp_tree; /* BGP packet tree */ proto_tree *bgp1_tree; /* BGP message tree */ int l, i; /* tmp */ int found; /* number of BGP messages in packet */ static u_char marker[] = { /* BGP message marker */ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, }; struct bgp bgp; /* BGP header */ int hlen; /* BGP header length */ char *typ; /* BGP message type */ if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "BGP"); if (check_col(pinfo->cinfo, COL_INFO)) col_clear(pinfo->cinfo, COL_INFO); l = tvb_reported_length(tvb); i = 0; found = -1; /* run through the TCP packet looking for BGP headers */ while (i + BGP_HEADER_SIZE <= l) { tvb_memcpy(tvb, bgp.bgp_marker, i, BGP_HEADER_SIZE); /* look for bgp header */ if (memcmp(bgp.bgp_marker, marker, sizeof(marker)) != 0) { i++; continue; } found++; hlen = ntohs(bgp.bgp_len); /* * Desegmentation check. */ if (bgp_desegment) { if (hlen > tvb_length_remaining(tvb, i) && pinfo->can_desegment) { /* * Not all of this packet is in the data we've been * handed, but we can do reassembly on it. * * Tell the TCP dissector where the data for * this message starts in the data it handed * us, and how many more bytes we need, and * return. */ pinfo->desegment_offset = i; pinfo->desegment_len = hlen - tvb_length_remaining(tvb, i); return; } } typ = val_to_str(bgp.bgp_type, bgptypevals, "Unknown Message"); if (check_col(pinfo->cinfo, COL_INFO)) { if (found == 0) col_add_fstr(pinfo->cinfo, COL_INFO, "%s", typ); else col_append_fstr(pinfo->cinfo, COL_INFO, ", %s", typ); } if (tree) { ti = proto_tree_add_item(tree, proto_bgp, tvb, i, hlen, FALSE); bgp_tree = proto_item_add_subtree(ti, ett_bgp); ti = proto_tree_add_text(bgp_tree, tvb, i, hlen, "%s", typ); /* add a different tree for each message type */ switch (bgp.bgp_type) { case BGP_OPEN: bgp1_tree = proto_item_add_subtree(ti, ett_bgp_open); break; case BGP_UPDATE: bgp1_tree = proto_item_add_subtree(ti, ett_bgp_update); break; case BGP_NOTIFICATION: bgp1_tree = proto_item_add_subtree(ti, ett_bgp_notification); break; case BGP_KEEPALIVE: bgp1_tree = proto_item_add_subtree(ti, ett_bgp); break; case BGP_ROUTE_REFRESH_CISCO: case BGP_ROUTE_REFRESH: bgp1_tree = proto_item_add_subtree(ti, ett_bgp_route_refresh); break; default: bgp1_tree = proto_item_add_subtree(ti, ett_bgp); break; } proto_tree_add_text(bgp1_tree, tvb, i, BGP_MARKER_SIZE, "Marker: 16 bytes"); if (hlen < BGP_HEADER_SIZE || hlen > BGP_MAX_PACKET_SIZE) { proto_tree_add_text(bgp1_tree, tvb, i + offsetof(struct bgp, bgp_len), 2, "Length (invalid): %u %s", hlen, (hlen == 1) ? "byte" : "bytes"); } else { proto_tree_add_text(bgp1_tree, tvb, i + offsetof(struct bgp, bgp_len), 2, "Length: %u %s", hlen, (hlen == 1) ? "byte" : "bytes"); } proto_tree_add_uint_format(bgp1_tree, hf_bgp_type, tvb, i + offsetof(struct bgp, bgp_type), 1, bgp.bgp_type, "Type: %s (%u)", typ, bgp.bgp_type); switch (bgp.bgp_type) { case BGP_OPEN: dissect_bgp_open(tvb, i, bgp1_tree); break; case BGP_UPDATE: dissect_bgp_update(tvb, i, bgp1_tree); break; case BGP_NOTIFICATION: dissect_bgp_notification(tvb, i, bgp1_tree); break; case BGP_KEEPALIVE: /* no data in KEEPALIVE messages */ break; case BGP_ROUTE_REFRESH_CISCO: case BGP_ROUTE_REFRESH: dissect_bgp_route_refresh(tvb, i, bgp1_tree); break; default: break; } } i += hlen; } } /* * Register ourselves. */ void proto_register_bgp(void) { static hf_register_info hf[] = { { &hf_bgp_type, { "BGP message type", "bgp.type", FT_UINT8, BASE_HEX, VALS(bgptypevals), 0x0, "BGP message type", HFILL }}, }; static gint *ett[] = { &ett_bgp, &ett_bgp_unfeas, &ett_bgp_attrs, &ett_bgp_attr, &ett_bgp_attr_flags, &ett_bgp_mp_nhna, &ett_bgp_mp_reach_nlri, &ett_bgp_mp_unreach_nlri, &ett_bgp_mp_snpa, &ett_bgp_nlri, &ett_bgp_open, &ett_bgp_update, &ett_bgp_notification, &ett_bgp_route_refresh, &ett_bgp_as_paths, &ett_bgp_communities, &ett_bgp_cluster_list, &ett_bgp_options, &ett_bgp_option, &ett_bgp_extended_communities }; module_t *bgp_module; proto_bgp = proto_register_protocol("Border Gateway Protocol", "BGP", "bgp"); proto_register_field_array(proto_bgp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); bgp_module = prefs_register_protocol(proto_bgp, NULL); prefs_register_bool_preference(bgp_module, "desegment", "Desegment all BGP messages spanning multiple TCP segments", "Whether the BGP dissector should desegment all messages spanning multiple TCP segments", &bgp_desegment); } void proto_reg_handoff_bgp(void) { dissector_handle_t bgp_handle; bgp_handle = create_dissector_handle(dissect_bgp, proto_bgp); dissector_add("tcp.port", BGP_TCP_PORT, bgp_handle); }