X-Git-Url: http://git.samba.org/samba.git/?a=blobdiff_plain;f=packet-gre.c;h=4d45bfd503d556d60031349a05f67747fcd18f0b;hb=56fbfeb884e75bbfc366171cd2af6209e395726f;hp=fb4faa4425466d139940f941591df9abf3613bc6;hpb=b9f98ccd202b9342401d30e5a5ab6132429441d7;p=obnox%2Fwireshark%2Fwip.git diff --git a/packet-gre.c b/packet-gre.c index fb4faa4425..4d45bfd503 100644 --- a/packet-gre.c +++ b/packet-gre.c @@ -2,23 +2,22 @@ * Routines for the Generic Routing Encapsulation (GRE) protocol * Brad Robel-Forrest * - * $Id: packet-gre.c,v 1.30 2000/11/29 06:17:34 guy Exp $ + * $Id: packet-gre.c,v 1.55 2004/01/29 03:51:25 guy Exp $ * * Ethereal - Network traffic analyzer - * By Gerald Combs + * 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. @@ -28,18 +27,22 @@ # include "config.h" #endif -#ifdef HAVE_SYS_TYPES_H -# include -#endif - -#ifdef HAVE_NETINET_IN_H -#include -#endif #include -#include "packet.h" -#include "packet-ip.h" -#include "packet-ipx.h" +#include #include "packet-wccp.h" +#include "in_cksum.h" +#include "etypes.h" +#include "greproto.h" +#include "ipproto.h" +#include "llcsaps.h" + +/* + * See RFC 1701 "Generic Routing Encapsulation (GRE)", RFC 1702 + * "Generic Routing Encapsulation over IPv4 networks", RFC 2637 + * "Point-to-Point Tunneling Protocol (PPTP)", RFC 2784 "Generic + * Routing Encapsulation (GRE)", and RFC 2890 "Key and Sequence + * Number Extensions to GRE". + */ static int proto_gre = -1; static int hf_gre_proto = -1; @@ -48,6 +51,9 @@ static gint ett_gre = -1; static gint ett_gre_flags = -1; static gint ett_gre_wccp2_redirect_header = -1; +static dissector_table_t gre_dissector_table; +static dissector_handle_t data_handle; + /* bit positions for flags in header */ #define GH_B_C 0x8000 #define GH_B_R 0x4000 @@ -60,267 +66,297 @@ static gint ett_gre_wccp2_redirect_header = -1; #define GH_R_FLAGS 0x00F8 #define GH_B_VER 0x0007 -#define GRE_PPP 0x880B -#define GRE_IP 0x0800 -#define GRE_WCCP 0x883E -#define GRE_IPX 0x8137 - -static void add_flags_and_ver(proto_tree *, guint16, int, int); -static void dissect_gre_wccp2_redirect_header(const u_char *, int, frame_data *, - proto_tree *); +static void add_flags_and_ver(proto_tree *, guint16, tvbuff_t *, int, int); +static void dissect_gre_wccp2_redirect_header(tvbuff_t *, int, proto_tree *); static const value_string typevals[] = { - { GRE_PPP, "PPP" }, - { GRE_IP, "IP" }, - { GRE_WCCP, "WCCP"}, - { GRE_IPX, "IPX"}, - { 0, NULL } + { ETHERTYPE_PPP, "PPP" }, + { ETHERTYPE_IP, "IP" }, + { SAP_OSINL5, "OSI"}, + { GRE_WCCP, "WCCP"}, + { ETHERTYPE_IPX, "IPX"}, + { ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" }, + { GRE_FR, "Frame Relay"}, + { ETHERTYPE_IPv6, "IPv6" }, + { 0, NULL } }; -static dissector_handle_t ip_handle; -static dissector_handle_t ppp_handle; - static void -dissect_gre(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) { - - guint16 flags_and_ver = pntohs(pd + offset); - guint16 type = pntohs(pd + offset + sizeof(flags_and_ver)); +dissect_gre(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ + int offset = 0; + guint16 flags_and_ver; + guint16 type; + gboolean is_ppp = FALSE; + gboolean is_wccp2 = FALSE; + guint len = 4; + proto_item *ti; + proto_tree *gre_tree = NULL; guint16 sre_af; guint8 sre_length; tvbuff_t *next_tvb; - OLD_CHECK_DISPLAY_AS_DATA(proto_gre, pd, offset, fd, tree); + flags_and_ver = tvb_get_ntohs(tvb, offset); + type = tvb_get_ntohs(tvb, offset + sizeof(flags_and_ver)); + + if (check_col(pinfo->cinfo, COL_PROTOCOL)) + col_set_str(pinfo->cinfo, COL_PROTOCOL, "GRE"); - if (check_col(fd, COL_PROTOCOL)) - col_set_str(fd, COL_PROTOCOL, "GRE"); - - if (check_col(fd, COL_INFO)) { - col_add_fstr(fd, COL_INFO, "Encapsulated %s", - val_to_str(type, typevals, "0x%04X (unknown)")); + if (check_col(pinfo->cinfo, COL_INFO)) { + col_add_fstr(pinfo->cinfo, COL_INFO, "Encapsulated %s", + val_to_str(type, typevals, "0x%04X (unknown)")); } - - if (IS_DATA_IN_FRAME(offset) && tree) { - gboolean is_ppp = FALSE; - gboolean is_wccp2 = FALSE; - proto_item * ti; - proto_tree * gre_tree; - guint len = 4; - - if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) - len += 4; - if (flags_and_ver & GH_B_K) + + if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) + len += 4; + if (flags_and_ver & GH_B_K) + len += 4; + if (flags_and_ver & GH_B_S) + len += 4; + switch (type) { + + case ETHERTYPE_PPP: + if (flags_and_ver & GH_P_A) len += 4; - if (flags_and_ver & GH_B_S) + is_ppp = TRUE; + break; + + case GRE_WCCP: + /* WCCP2 puts an extra 4 octets into the header, but uses the same + encapsulation type; if it looks as if the first octet of the packet + isn't the beginning of an IPv4 header, assume it's WCCP2. */ + if ((tvb_get_guint8(tvb, offset + sizeof(flags_and_ver) + sizeof(type)) & 0xF0) != 0x40) { len += 4; - switch (type) { - - case GRE_PPP: - if (flags_and_ver & GH_P_A) - len += 4; - is_ppp = TRUE; - break; - - case GRE_WCCP: - /* WCCP2 apparently puts an extra 4 octets into the header, but uses - the same encapsulation type; if it looks as if the first octet of - the packet isn't the beginning of an IPv4 header, assume it's - WCCP2. */ - if ((pd[offset + sizeof(flags_and_ver) + sizeof(type)] & 0xF0) != 0x40) { - len += 4; - is_wccp2 = TRUE; - } - break; + is_wccp2 = TRUE; } + break; + } - ti = proto_tree_add_protocol_format(tree, proto_gre, NullTVB, offset, len, + if (tree) { + ti = proto_tree_add_protocol_format(tree, proto_gre, tvb, offset, len, "Generic Routing Encapsulation (%s)", val_to_str(type, typevals, "0x%04X - unknown")); gre_tree = proto_item_add_subtree(ti, ett_gre); - add_flags_and_ver(gre_tree, flags_and_ver, offset, is_ppp); - - offset += sizeof(flags_and_ver); - - proto_tree_add_uint(gre_tree, hf_gre_proto, NullTVB, offset, sizeof(type), type); - offset += sizeof(type); + add_flags_and_ver(gre_tree, flags_and_ver, tvb, offset, is_ppp); + } + offset += sizeof(flags_and_ver); - if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) { - guint16 checksum = pntohs(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(checksum), - "Checksum: %u", checksum); - offset += sizeof(checksum); + if (tree) { + proto_tree_add_uint(gre_tree, hf_gre_proto, tvb, offset, sizeof(type), type); + } + offset += sizeof(type); + + if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) { + if (tree) { + guint length, reported_length; + vec_t cksum_vec[1]; + guint16 cksum, computed_cksum; + + cksum = tvb_get_ntohs(tvb, offset); + length = tvb_length(tvb); + reported_length = tvb_reported_length(tvb); + if ((flags_and_ver & GH_B_C) && !pinfo->fragmented + && length >= reported_length) { + /* The Checksum Present bit is set, and the packet isn't part of a + fragmented datagram and isn't truncated, so we can checksum it. */ + + cksum_vec[0].ptr = tvb_get_ptr(tvb, 0, reported_length); + cksum_vec[0].len = reported_length; + computed_cksum = in_cksum(cksum_vec, 1); + if (computed_cksum == 0) { + proto_tree_add_text(gre_tree, tvb, offset, 2, + "Checksum: 0x%04x (correct)", cksum); + } else { + proto_tree_add_text(gre_tree, tvb, offset, 2, + "Checksum: 0x%04x (incorrect, should be 0x%04x)", + cksum, in_cksum_shouldbe(cksum, computed_cksum)); + } + } else { + proto_tree_add_text(gre_tree, tvb, offset, 2, + "Checksum: 0x%04x", cksum); + } } - - if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) { - guint16 rtoffset = pntohs(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(rtoffset), - "Offset: %u", rtoffset); - offset += sizeof(rtoffset); + offset += 2; + } + + if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) { + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 2, + "Offset: %u", tvb_get_ntohs(tvb, offset)); } + offset += 2; + } - if (flags_and_ver & GH_B_K) { - if (is_ppp) { - guint16 paylen; - guint16 callid; - - paylen = pntohs(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(paylen), - "Payload length: %u", paylen); - offset += sizeof(paylen); - - callid = pntohs(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(callid), - "Call ID: %u", callid); - offset += sizeof(callid); + if (flags_and_ver & GH_B_K) { + if (is_ppp) { + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 2, + "Payload length: %u", tvb_get_ntohs(tvb, offset)); } - else { - guint32 key = pntohl(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(key), - "Key: %u", key); - offset += sizeof(key); + offset += 2; + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 2, + "Call ID: %u", tvb_get_ntohs(tvb, offset)); } + offset += 2; } - - if (flags_and_ver & GH_B_S) { - guint32 seqnum = pntohl(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(seqnum), - "Sequence number: %u", seqnum); - offset += sizeof(seqnum); + else { + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 4, + "Key: %u", tvb_get_ntohl(tvb, offset)); + } + offset += 4; } + } - if (is_ppp && flags_and_ver & GH_P_A) { - guint32 acknum = pntohl(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(acknum), - "Acknowledgement number: %u", acknum); - offset += sizeof(acknum); + if (flags_and_ver & GH_B_S) { + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 4, + "Sequence number: %u", tvb_get_ntohl(tvb, offset)); } + offset += 4; + } - if (flags_and_ver & GH_B_R) { - for (;;) { - sre_af = pntohs(pd + offset); - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(guint16), + if (is_ppp && flags_and_ver & GH_P_A) { + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 4, + "Acknowledgement number: %u", tvb_get_ntohl(tvb, offset)); + } + offset += 4; + } + + if (flags_and_ver & GH_B_R) { + for (;;) { + sre_af = tvb_get_ntohs(tvb, offset); + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, sizeof(guint16), "Address family: %u", sre_af); - offset += sizeof(guint16); - proto_tree_add_text(gre_tree, NullTVB, offset, 1, - "SRE offset: %u", pd[offset++]); - sre_length = pd[offset]; - proto_tree_add_text(gre_tree, NullTVB, offset, sizeof(guint8), + } + offset += sizeof(guint16); + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, 1, + "SRE offset: %u", tvb_get_guint8(tvb, offset)); + } + offset += sizeof(guint8); + sre_length = tvb_get_guint8(tvb, offset); + if (tree) { + proto_tree_add_text(gre_tree, tvb, offset, sizeof(guint8), "SRE length: %u", sre_length); - offset += sizeof(guint8); - if (sre_af == 0 && sre_length == 0) - break; - offset += sre_length; } + offset += sizeof(guint8); + if (sre_af == 0 && sre_length == 0) + break; + offset += sre_length; } + } - switch (type) { - case GRE_PPP: - old_call_dissector(ppp_handle, pd, offset, fd, tree); - break; - case GRE_IP: - old_call_dissector(ip_handle, pd, offset, fd, tree); - break; - case GRE_WCCP: - if (is_wccp2) { - dissect_gre_wccp2_redirect_header(pd, offset, fd, gre_tree); - offset += 4; - } - old_call_dissector(ip_handle, pd, offset, fd, tree); - break; - case GRE_IPX: - next_tvb = tvb_create_from_top(offset); - dissect_ipx(next_tvb, &pi, tree); - break; - default: - next_tvb = tvb_create_from_top(offset); - dissect_data(next_tvb, 0, &pi, gre_tree); - break; + if (type == GRE_WCCP) { + if (is_wccp2) { + if (tree) + dissect_gre_wccp2_redirect_header(tvb, offset, gre_tree); + offset += 4; } } + + /* If the S bit is not set, this packet might not have a payload, so + check whether there's any data left, first. + + XXX - the S bit isn't in RFC 2784, which deprecates that bit + and some other bits in RFC 1701 and says that they should be + zero for RFC 2784-compliant GRE; as such, the absence of the + S bit doesn't necessarily mean there's no payload. */ + if (!(flags_and_ver & GH_B_S)) { + if (tvb_reported_length_remaining(tvb, offset) <= 0) + return; /* no payload */ + } + next_tvb = tvb_new_subset(tvb, offset, -1, -1); + if (!dissector_try_port(gre_dissector_table, type, next_tvb, pinfo, tree)) + call_dissector(data_handle,next_tvb, pinfo, gre_tree); } static void -add_flags_and_ver(proto_tree *tree, guint16 flags_and_ver, int offset, int is_ppp) { - +add_flags_and_ver(proto_tree *tree, guint16 flags_and_ver, tvbuff_t *tvb, + int offset, int is_ppp) +{ proto_item * ti; proto_tree * fv_tree; int nbits = sizeof(flags_and_ver) * 8; - - ti = proto_tree_add_text(tree, NullTVB, offset, 2, + + ti = proto_tree_add_text(tree, tvb, offset, 2, "Flags and version: %#04x", flags_and_ver); fv_tree = proto_item_add_subtree(ti, ett_gre_flags); - - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_boolean_bitfield(flags_and_ver, GH_B_C, nbits, "Checksum", "No checksum")); - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_boolean_bitfield(flags_and_ver, GH_B_R, nbits, "Routing", "No routing")); - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_boolean_bitfield(flags_and_ver, GH_B_K, nbits, "Key", "No key")); - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_boolean_bitfield(flags_and_ver, GH_B_S, nbits, "Sequence number", "No sequence number")); - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_boolean_bitfield(flags_and_ver, GH_B_s, nbits, "Strict source route", "No strict source route")); - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_numeric_bitfield(flags_and_ver, GH_B_RECUR, nbits, "Recursion control: %u")); if (is_ppp) { - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_boolean_bitfield(flags_and_ver, GH_P_A, nbits, "Acknowledgment number", "No acknowledgment number")); - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_numeric_bitfield(flags_and_ver, GH_P_FLAGS, nbits, "Flags: %u")); } else { - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_numeric_bitfield(flags_and_ver, GH_R_FLAGS, nbits, "Flags: %u")); } - proto_tree_add_text(fv_tree, NullTVB, offset, sizeof(flags_and_ver), "%s", + proto_tree_add_text(fv_tree, tvb, offset, sizeof(flags_and_ver), "%s", decode_numeric_bitfield(flags_and_ver, GH_B_VER, nbits, "Version: %u")); } static void -dissect_gre_wccp2_redirect_header(const u_char *pd, int offset, frame_data *fd, - proto_tree *tree) +dissect_gre_wccp2_redirect_header(tvbuff_t *tvb, int offset, proto_tree *tree) { proto_item * ti; proto_tree * rh_tree; guint8 rh_flags; - - ti = proto_tree_add_text(tree, NullTVB, offset, 4, "Redirect header"); + + ti = proto_tree_add_text(tree, tvb, offset, 4, "Redirect header"); rh_tree = proto_item_add_subtree(ti, ett_gre_wccp2_redirect_header); - rh_flags = pd[offset]; - proto_tree_add_text(rh_tree, NullTVB, offset, 1, "%s", + rh_flags = tvb_get_guint8(tvb, offset); + proto_tree_add_text(rh_tree, tvb, offset, 1, "%s", decode_boolean_bitfield(rh_flags, 0x80, 8, "Dynamic service", "Well-known service")); - proto_tree_add_text(rh_tree, NullTVB, offset, 1, "%s", + proto_tree_add_text(rh_tree, tvb, offset, 1, "%s", decode_boolean_bitfield(rh_flags, 0x40, 8, "Alternative bucket used", "Alternative bucket not used")); - proto_tree_add_text(rh_tree, NullTVB, offset + 1, 1, "Service ID: %s", - val_to_str(pd[offset + 1], service_id_vals, "Unknown (0x%02X)")); + proto_tree_add_text(rh_tree, tvb, offset + 1, 1, "Service ID: %s", + val_to_str(tvb_get_guint8(tvb, offset + 1), service_id_vals, "Unknown (0x%02X)")); if (rh_flags & 0x40) - proto_tree_add_text(rh_tree, NullTVB, offset + 2, 1, "Alternative bucket index: %u", - pd[offset + 2]); - proto_tree_add_text(rh_tree, NullTVB, offset + 3, 1, "Primary bucket index: %u", - pd[offset + 3]); + proto_tree_add_text(rh_tree, tvb, offset + 2, 1, "Alternative bucket index: %u", + tvb_get_guint8(tvb, offset + 2)); + proto_tree_add_text(rh_tree, tvb, offset + 3, 1, "Primary bucket index: %u", + tvb_get_guint8(tvb, offset + 3)); } - + void proto_register_gre(void) { static hf_register_info hf[] = { { &hf_gre_proto, { "Protocol Type", "gre.proto", FT_UINT16, BASE_HEX, VALS(typevals), 0x0, - "The protocol that is GRE encapsulated"} + "The protocol that is GRE encapsulated", HFILL } }, }; static gint *ett[] = { @@ -329,19 +365,22 @@ proto_register_gre(void) &ett_gre_wccp2_redirect_header, }; - proto_gre = proto_register_protocol("Generic Routing Encapsulation", "gre"); + proto_gre = proto_register_protocol("Generic Routing Encapsulation", + "GRE", "gre"); proto_register_field_array(proto_gre, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); + + /* subdissector code */ + gre_dissector_table = register_dissector_table("gre.proto", + "GRE protocol type", FT_UINT16, BASE_HEX); } void proto_reg_handoff_gre(void) { - old_dissector_add("ip.proto", IP_PROTO_GRE, dissect_gre); + dissector_handle_t gre_handle; - /* - * Get handles for the IP and PPP dissectors. - */ - ip_handle = find_dissector("ip"); - ppp_handle = find_dissector("ppp"); + gre_handle = create_dissector_handle(dissect_gre, proto_gre); + dissector_add("ip.proto", IP_PROTO_GRE, gre_handle); + data_handle = find_dissector("data"); }