From 34450a8a3570e8f03c503d849e78f7a2ac5e9349 Mon Sep 17 00:00:00 2001 From: Gilbert Ramirez Date: Fri, 11 Jun 1999 15:30:55 +0000 Subject: Added PPPoE, PPTP, GRE, and ISAKMP dissectors. svn path=/trunk/; revision=303 --- packet-gre.c | 237 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 237 insertions(+) create mode 100644 packet-gre.c (limited to 'packet-gre.c') diff --git a/packet-gre.c b/packet-gre.c new file mode 100644 index 0000000000..c03d8ddcbf --- /dev/null +++ b/packet-gre.c @@ -0,0 +1,237 @@ +/* packet-gre.c + * Routines for the Generic Routing Encapsulation (GRE) protocol + * Brad Robel-Forrest + * + * $Id: packet-gre.c,v 1.1 1999/06/11 15:30:37 gram Exp $ + * + * 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 + +#ifdef HAVE_SYS_TYPES_H +# include +#endif + +#include +#include +#include "packet.h" + +/* bit positions for flags in header */ +#define GH_B_C 0x8000 +#define GH_B_R 0x4000 +#define GH_B_K 0x2000 +#define GH_B_S 0x1000 +#define GH_B_s 0x0800 +#define GH_B_RECUR 0x0700 +#define GH_P_A 0x0080 /* only in special PPTPized GRE header */ +#define GH_P_FLAGS 0x0078 /* only in special PPTPized GRE header */ +#define GH_R_FLAGS 0x00F8 +#define GH_B_VER 0x0007 + +#define GRE_PPP 0x880B + +static int calc_len(guint16, int); +static void add_flags_and_ver(proto_tree *, guint16, int, int); + +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)); + static const value_string typevals[] = { + { GRE_PPP, "PPP" }, + { 0, NULL } + }; + + if (check_col(fd, COL_PROTOCOL)) + col_add_str(fd, COL_PROTOCOL, "GRE"); + + if (check_col(fd, COL_INFO)) { + if (type == GRE_PPP) + col_add_str(fd, COL_INFO, "Encapsulated PPP"); + else + col_add_str(fd, COL_INFO, "Encapsulated unknown"); + } + + if (fd->cap_len > offset && tree) { + int is_ppp; + proto_item * ti; + proto_tree * gre_tree; + + if (type == GRE_PPP) { + is_ppp = 1; + ti = proto_tree_add_item(tree, offset, calc_len(flags_and_ver, 1), + "Generic Routing Encapsulation (PPP)"); + gre_tree = proto_tree_new(); + proto_item_add_subtree(ti, gre_tree, ETT_GRE); + add_flags_and_ver(gre_tree, flags_and_ver, offset, 1); + } + else { + is_ppp = 0; + ti = proto_tree_add_item(tree, offset, calc_len(flags_and_ver, 1), + "Generic Routing Encapsulation"); + gre_tree = proto_tree_new(); + proto_item_add_subtree(ti, gre_tree, ETT_GRE); + add_flags_and_ver(gre_tree, flags_and_ver, offset, 0); + } + + offset += sizeof(flags_and_ver); + + proto_tree_add_item(gre_tree, offset, sizeof(type), + "Protocol Type: %s (%#04x)", + val_to_str(type, typevals, "Unknown"), type); + offset += sizeof(type); + + if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) { + guint16 checksum = pntohs(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(checksum), + "Checksum: %u", checksum); + offset += sizeof(checksum); + } + + if (flags_and_ver & GH_B_C || flags_and_ver & GH_B_R) { + guint16 rtoffset = pntohs(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(rtoffset), + "Offset: %u", rtoffset); + offset += sizeof(rtoffset); + } + + if (flags_and_ver & GH_B_K) { + if (is_ppp) { + guint16 paylen; + guint16 callid; + + paylen = pntohs(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(paylen), + "Payload length: %u", paylen); + offset += sizeof(paylen); + + callid = pntohs(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(callid), + "Call ID: %u", callid); + offset += sizeof(callid); + } + else { + guint32 key = pntohl(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(key), + "Key: %u", key); + offset += sizeof(key); + } + } + + if (flags_and_ver & GH_B_S) { + guint32 seqnum = pntohl(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(seqnum), + "Sequence number: %u", seqnum); + offset += sizeof(seqnum); + } + + if (is_ppp && flags_and_ver & GH_P_A) { + guint32 acknum = pntohl(pd + offset); + proto_tree_add_item(gre_tree, offset, sizeof(acknum), + "Acknowledgement number: %u", acknum); + offset += sizeof(acknum); + } + + if (flags_and_ver & GH_B_R) { + proto_tree_add_item(gre_tree, offset, sizeof(guint16), + "Address family: %u", pntohs(pd + offset)); + offset += sizeof(guint16); + proto_tree_add_item(gre_tree, offset, 1, + "SRE offset: %u", pd[offset++]); + proto_tree_add_item(gre_tree, offset, 1, + "SRE length: %u", pd[offset++]); + } + + switch (type) { + case GRE_PPP: + dissect_payload_ppp(pd, offset, fd, tree); + break; + default: + dissect_data(pd, offset, fd, gre_tree); + } + } +} + +static int +calc_len(guint16 flags_and_ver, int is_ppp) { + + int len = 4; + + 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; + if (is_ppp && flags_and_ver & GH_P_A) len += 4; + + return len; +} + +static void +add_flags_and_ver(proto_tree *tree, guint16 flags_and_ver, int offset, int is_ppp) { + + proto_item * ti; + proto_tree * fv_tree; + int nbits = sizeof(flags_and_ver) * 8; + + ti = proto_tree_add_item(tree, offset, 2, + "Flags and version: %#08x", flags_and_ver); + fv_tree = proto_tree_new(); + proto_item_add_subtree(ti, fv_tree, ETT_GRE_FLAGS); + + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_boolean_bitfield(flags_and_ver, GH_B_C, nbits, + "Checksum", "No checksum")); + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_boolean_bitfield(flags_and_ver, GH_B_R, nbits, + "Routing", "No routing")); + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_boolean_bitfield(flags_and_ver, GH_B_K, nbits, + "Key", "No key")); + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_boolean_bitfield(flags_and_ver, GH_B_S, nbits, + "Sequence number", "No sequence number")); + proto_tree_add_item(fv_tree, 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_item(fv_tree, 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_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_boolean_bitfield(flags_and_ver, GH_P_A, nbits, + "Acknowledgment number", "No acknowledgment number")); + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_numeric_bitfield(flags_and_ver, GH_P_FLAGS, nbits, + "Flags: %u")); + } + else { + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_numeric_bitfield(flags_and_ver, GH_R_FLAGS, nbits, + "Flags: %u")); + } + + proto_tree_add_item(fv_tree, offset, sizeof(flags_and_ver), "%s", + decode_numeric_bitfield(flags_and_ver, GH_B_VER, nbits, + "Version: %u")); + } + -- cgit v1.2.3