3 * $Id: packet-tripe.c,v 1.4 2004/04/18 18:08:11 mdw Exp $
5 * TrIPE protocol dissector for Ethereal
7 * (c) 2003 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Trivial IP Encryption (TrIPE).
14 * TrIPE is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * TrIPE is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with TrIPE; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Header files ------------------------------------------------------*/
37 #include <netinet/in.h>
41 #include <epan/packet.h>
44 #ifdef ETHEREAL_BUGGERED
45 # define plugin_address_table_t void
46 # define plugin_address_table_init(x)
48 # include <plugins/plugin_api.h>
51 #include "tripe-protocol.h"
53 /*----- Static variables --------------------------------------------------*/
55 static int proto_tripe = -1;
57 static guint hashsz = 20, tagsz = 10, ivsz = 8;
60 int hf, hf_len, hf_val, tt;
63 int hf, hf_len, hf_val, hfx_len, hfx_val, hfy_len, hfy_val, tt;
66 static int hf_tripe_cat = -1;
67 static int hf_tripe_packet_type = -1;
68 static int hf_tripe_ct = -1;
69 static int hf_tripe_ct_seq = -1;
70 static int hf_tripe_ct_iv = -1;
71 static int hf_tripe_ct_ct = -1;
72 static int hf_tripe_ct_tag = -1;
73 static int hf_tripe_kx_type = -1;
74 static hfge hf_tripe_kx_mychal = { -1, -1, -1, -1, -1, -1, -1, -1 };
75 static int hf_tripe_kx_mycookie = -1;
76 static int hf_tripe_kx_yourcookie = -1;
77 static hfmp hf_tripe_kx_check = { -1, -1, -1, -1 };
78 static int hf_tripe_huh = -1;
80 static int tt_tripe = -1;
81 static int tt_tripe_ct = -1;
83 G_MODULE_EXPORT const gchar version[] = VERSION;
85 /*----- Main code ---------------------------------------------------------*/
87 static void prefcb(void) { }
89 static gint gethash(proto_tree *tt, int hf, tvbuff_t *b, gint off)
91 proto_tree_add_item(tt, hf, b, off, hashsz, FALSE);
92 return (off + hashsz);
95 static gint getmp(proto_tree *tt, const hfmp *hf, tvbuff_t *b, gint off)
97 guint16 len = tvb_get_ntohs(b, off);
98 proto_item *ti = proto_tree_add_item(tt, hf->hf, b, off, len + 2, FALSE);
99 tt = proto_item_add_subtree(ti, hf->tt);
100 proto_tree_add_item(tt, hf->hf_len, b, off, 2, FALSE);
101 proto_tree_add_item(tt, hf->hf_val, b, off + 2, len, FALSE);
102 return (off + 2 + len);
105 static gint getge(proto_tree *tt, const hfge *hf, tvbuff_t *b, gint off)
107 guint16 len = tvb_get_ntohs(b, off), len2;
110 r = tvb_length_remaining(b, off);
112 (len2 = tvb_get_ntohs(b, off + 2 + len), r < 4 + len + len2)) {
113 ti = proto_tree_add_item(tt, hf->hf, b, off, len + 2, FALSE);
114 tt = proto_item_add_subtree(ti, hf->tt);
115 proto_tree_add_item(tt, hf->hf_len, b, off, 2, FALSE);
116 proto_tree_add_item(tt, hf->hf_val, b, off + 2, len, FALSE);
119 ti = proto_tree_add_item(tt, hf->hf, b, off, len + len2 + 4, FALSE);
120 tt = proto_item_add_subtree(ti, hf->tt);
121 proto_tree_add_item(tt, hf->hfx_len, b, off, 2, FALSE);
122 proto_tree_add_item(tt, hf->hfx_val, b, off + 2, len, FALSE);
123 proto_tree_add_item(tt, hf->hfy_len, b, off + 2 + len, 2, FALSE);
124 proto_tree_add_item(tt, hf->hfy_val, b, off + 4 + len, len2, FALSE);
125 r = off + len + len2 + 4;
130 static void dissect_tripe(tvbuff_t *b, packet_info *p, proto_tree *t)
135 gint off = tvb_raw_offset(b);
138 /* --- Initialize the summary cells --- */
140 if (check_col(p->cinfo, COL_PROTOCOL))
141 col_set_str(p->cinfo, COL_PROTOCOL, "TrIPE");
142 ty = tvb_get_guint8(b, 0);
143 if (check_col(p->cinfo, COL_INFO)) {
144 col_clear(p->cinfo, COL_INFO);
145 switch (ty & MSG_CATMASK) {
147 switch (ty & MSG_TYPEMASK) {
149 col_set_str(p->cinfo, COL_INFO, "Packet data");
152 col_add_fstr(p->cinfo, COL_INFO,
153 "Packet data, unknown type code %u",
159 switch (ty & MSG_TYPEMASK) {
161 col_set_str(p->cinfo, COL_INFO, "Key exchange, prechallenge");
164 col_set_str(p->cinfo, COL_INFO, "Key exchange, cookie");
167 col_set_str(p->cinfo, COL_INFO, "Key exchange, challenge");
170 col_set_str(p->cinfo, COL_INFO, "Key exchange, reply");
173 col_set_str(p->cinfo, COL_INFO, "Key exchange, switch request");
176 col_set_str(p->cinfo, COL_INFO, "Key exchange, switch response");
179 col_add_fstr(p->cinfo, COL_INFO,
180 "Key exchange, unknown type code %u",
186 col_add_fstr(p->cinfo, COL_INFO,
187 "Unknown category code %u, unknown type code %u",
188 ty & MSG_CATMASK, ty & MSG_TYPEMASK);
193 /* --- Fill in the tree --- */
196 ti = proto_tree_add_item(t, proto_tripe, b, 0, -1, FALSE);
197 tt = proto_item_add_subtree(ti, tt_tripe);
199 proto_tree_add_item(tt, hf_tripe_cat, b, 0, 1, FALSE);
202 switch (ty & MSG_CATMASK) {
204 proto_tree_add_item(tt, hf_tripe_packet_type, b, 0, 1, FALSE);
205 switch (ty & MSG_TYPEMASK) {
213 proto_tree_add_item(tt, hf_tripe_kx_type, b, 0, 1, FALSE);
214 switch (ty & MSG_TYPEMASK) {
216 off = getge(tt, &hf_tripe_kx_mychal, b, off);
219 off = getge(tt, &hf_tripe_kx_mychal, b, off);
220 off = gethash(tt, hf_tripe_kx_yourcookie, b, off);
223 off = getge(tt, &hf_tripe_kx_mychal, b, off);
224 off = gethash(tt, hf_tripe_kx_yourcookie, b, off);
225 off = getmp(tt, &hf_tripe_kx_check, b, off);
228 off = gethash(tt, hf_tripe_kx_mycookie, b, off);
229 off = gethash(tt, hf_tripe_kx_yourcookie, b, off);
230 off = getmp(tt, &hf_tripe_kx_check, b, off);
233 off = gethash(tt, hf_tripe_kx_mycookie, b, off);
234 off = gethash(tt, hf_tripe_kx_yourcookie, b, off);
246 if (tvb_offset_exists(b, off))
250 proto_tree_add_item(tt, hf_tripe_huh, b, off, -1, FALSE);
253 ti = proto_tree_add_item(tt, hf_tripe_ct, b, off, -1, FALSE);
254 seq = tvb_get_ntohl(b, off + tagsz);
255 proto_item_set_text(ti, "Encrypted ciphertext (sequence number %lu)",
257 tt = proto_item_add_subtree(ti, tt_tripe_ct);
259 proto_tree_add_item(tt, hf_tripe_ct_tag, b, off, tagsz, FALSE);
262 proto_tree_add_item(tt, hf_tripe_ct_seq, b, off, 4, FALSE);
265 proto_tree_add_item(tt, hf_tripe_ct_iv, b, off, ivsz, FALSE);
268 proto_tree_add_item(ti, hf_tripe_ct_ct, b, off, -1, FALSE);
274 void proto_register_tripe(void)
278 static value_string vs_kxtype[] = {
279 { KX_PRECHAL, "KX_PRECHAL (prechallenge)" },
280 { KX_COOKIE, "KX_COOKIE (cookie)" },
281 { KX_CHAL, "KX_CHAL (challenge)" },
282 { KX_REPLY, "KX_REPLY (reply)" },
283 { KX_SWITCH, "KX_SWITCH (switch request)" },
284 { KX_SWITCHOK, "KX_SWITCHOK (switch response)" },
288 static hf_register_info hfs[] = {
290 "Message category", "tripe.cat",
291 FT_UINT8, BASE_HEX, 0, MSG_CATMASK
293 &hf_tripe_packet_type, {
294 "Packet message type", "tripe.packet.type",
295 FT_UINT8, BASE_HEX, 0, MSG_TYPEMASK,
296 "This is the TrIPE packet type subcode."
299 "Encrypted ciphertext", "tripe.ct",
300 FT_BYTES, BASE_NONE, 0, 0,
301 "This is an encrypted message."
304 "Ciphertext sequence number", "tripe.ct.seq",
305 FT_UINT32, BASE_DEC, 0, 0,
306 "This is the unique sequence number for the ciphertext."
309 "Ciphertext initialization vector", "tripe.ct.iv",
310 FT_BYTES, BASE_NONE, 0, 0,
311 "This is the initialization vector used for the actual encryption."
314 "Actual encrypted data", "tripe.ct.ct",
315 FT_BYTES, BASE_NONE, 0, 0,
316 "This is the encrypted message. Reading it ought to be hard."
319 "Message authentication code", "tripe.ct.tag",
320 FT_BYTES, BASE_NONE, 0, 0,
321 "This is the message authentication code tag for the ciphertext."
324 "Key-exchange message type", "tripe.kx.type",
325 FT_UINT8, BASE_HEX, vs_kxtype, MSG_TYPEMASK,
326 "This is the TrIPE key-exchange type subcode."
328 &hf_tripe_kx_mychal.hf, {
329 "Sender's challenge data", "tripe.kx.mychal",
330 FT_BYTES, BASE_NONE, 0, 0,
331 "This is the sender's challenge."
333 &hf_tripe_kx_mychal.hf_len, {
334 "Challenge length", "tripe.kx.mychal.len",
335 FT_UINT16, BASE_DEC, 0, 0,
336 "This is the length of the sender's challenge."
338 &hf_tripe_kx_mychal.hf_val, {
339 "Challenge", "tripe.kx.mychal.val",
340 FT_BYTES, BASE_NONE, 0, 0,
341 "This is the value of the sender's challenge."
343 &hf_tripe_kx_mychal.hfx_len, {
344 "Challenge x length", "tripe.kx.mychal.x.len",
345 FT_UINT16, BASE_DEC, 0, 0,
346 "This is the length of the sender's challenge x-coordinate."
348 &hf_tripe_kx_mychal.hfy_val, {
349 "Challenge x value", "tripe.kx.mychal.x.val",
350 FT_BYTES, BASE_NONE, 0, 0,
351 "This is the value of the sender's challenge x-coordinate."
353 &hf_tripe_kx_mychal.hfy_len, {
354 "Challenge y length", "tripe.kx.mychal.y.len",
355 FT_UINT16, BASE_DEC, 0, 0,
356 "This is the length of the sender's challenge x-coordinate."
358 &hf_tripe_kx_mychal.hfx_val, {
359 "Challenge y value", "tripe.kx.mychal.y.val",
360 FT_BYTES, BASE_NONE, 0, 0,
361 "This is the value of the sender's challenge x-coordinate."
363 &hf_tripe_kx_mycookie, {
364 "Sender's hashed cookie", "tripe.kx.mycookie",
365 FT_BYTES, BASE_NONE, 0, 0,
366 "This is the hash of the sender's challenge."
368 &hf_tripe_kx_yourcookie, {
369 "Recipient's hashed cookie", "tripe.kx.yourcookie",
370 FT_BYTES, BASE_NONE, 0, 0,
371 "This is the hash of the recipient's challenge."
373 &hf_tripe_kx_check.hf, {
374 "Challenge check-value", "tripe.kx.check",
375 FT_BYTES, BASE_NONE, 0, 0,
376 "This is an encrypted check-value which proves that the sender "
377 "knows the answer to the challenge, and that it is therefore honest."
379 &hf_tripe_kx_check.hf_len, {
380 "Check-value length", "tripe.kx.check.len",
381 FT_UINT16, BASE_DEC, 0, 0,
382 "This is the length of the encrypted check-value."
384 &hf_tripe_kx_check.hf_val, {
385 "Check-value data", "tripe.kx.check.val",
386 FT_BYTES, BASE_NONE, 0, 0,
387 "This is the actual encrypted check-value."
390 "Unknown data", "tripe.huh",
391 FT_BYTES, BASE_NONE, 0, 0,
392 "I don't know what's meant to appear here."
396 static gint *tts[] = {
399 &hf_tripe_kx_mychal.tt,
400 &hf_tripe_kx_check.tt,
403 proto_tripe = proto_register_protocol("TrIPE", "TrIPE", "tripe");
404 proto_register_field_array(proto_tripe, hfs, array_length(hfs));
405 proto_register_subtree_array(tts, array_length(tts));
407 mod = prefs_register_protocol(proto_tripe, prefcb);
408 prefs_register_uint_preference(mod, "hashsz", "Hash length",
409 "hash function output length (in octets)",
411 prefs_register_uint_preference(mod, "tagsz", "MAC tag length",
412 "MAC tag length (in octets)", 10, &tagsz);
413 prefs_register_uint_preference(mod, "ivsz", "IV length",
414 "block cipher initialization vector length"
419 void proto_reg_handoff_tripe(void)
421 dissector_handle_t dh;
423 dh = create_dissector_handle(dissect_tripe, proto_tripe);
424 dissector_add("udp.port", 22003, dh);
427 G_MODULE_EXPORT void plugin_reg_handoff(void)
429 proto_reg_handoff_tripe();
432 G_MODULE_EXPORT void plugin_init(plugin_address_table_t *pat)
434 plugin_address_table_init(pat);
435 if (proto_tripe == -1)
436 proto_register_tripe();
439 /*----- That's all, folks -------------------------------------------------*/