1/**
2 * Copyright (c) 2012
3 *
4 * Gregory Detal <gregory.detal@uclouvain.be>
5 * Christoph Paasch <christoph.paasch@uclouvain.be>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * 3. Neither the name of the University nor of the Laboratory may be used
19 *    to endorse or promote products derived from this software without
20 *    specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35/* \summary: Multipath TCP (MPTCP) printer */
36
37/* specification: RFC 6824 */
38
39#ifdef HAVE_CONFIG_H
40#include "config.h"
41#endif
42
43#include <netdissect-stdinc.h>
44
45#include "netdissect.h"
46#include "extract.h"
47#include "addrtoname.h"
48
49#include "tcp.h"
50
51#define MPTCP_SUB_CAPABLE       0x0
52#define MPTCP_SUB_JOIN          0x1
53#define MPTCP_SUB_DSS           0x2
54#define MPTCP_SUB_ADD_ADDR      0x3
55#define MPTCP_SUB_REMOVE_ADDR   0x4
56#define MPTCP_SUB_PRIO          0x5
57#define MPTCP_SUB_FAIL          0x6
58#define MPTCP_SUB_FCLOSE        0x7
59
60struct mptcp_option {
61        uint8_t        kind;
62        uint8_t        len;
63        uint8_t        sub_etc;        /* subtype upper 4 bits, other stuff lower 4 bits */
64};
65
66#define MPTCP_OPT_SUBTYPE(sub_etc)      (((sub_etc) >> 4) & 0xF)
67
68struct mp_capable {
69        uint8_t        kind;
70        uint8_t        len;
71        uint8_t        sub_ver;
72        uint8_t        flags;
73        uint8_t        sender_key[8];
74        uint8_t        receiver_key[8];
75};
76
77#define MP_CAPABLE_OPT_VERSION(sub_ver) (((sub_ver) >> 0) & 0xF)
78#define MP_CAPABLE_C                    0x80
79#define MP_CAPABLE_S                    0x01
80
81struct mp_join {
82        uint8_t        kind;
83        uint8_t        len;
84        uint8_t        sub_b;
85        uint8_t        addr_id;
86        union {
87                struct {
88                        uint8_t         token[4];
89                        uint8_t         nonce[4];
90                } syn;
91                struct {
92                        uint8_t         mac[8];
93                        uint8_t         nonce[4];
94                } synack;
95                struct {
96                        uint8_t        mac[20];
97                } ack;
98        } u;
99};
100
101#define MP_JOIN_B                       0x01
102
103struct mp_dss {
104        uint8_t        kind;
105        uint8_t        len;
106        uint8_t        sub;
107        uint8_t        flags;
108};
109
110#define MP_DSS_F                        0x10
111#define MP_DSS_m                        0x08
112#define MP_DSS_M                        0x04
113#define MP_DSS_a                        0x02
114#define MP_DSS_A                        0x01
115
116struct mp_add_addr {
117        uint8_t        kind;
118        uint8_t        len;
119        uint8_t        sub_ipver;
120        uint8_t        addr_id;
121        union {
122                struct {
123                        uint8_t         addr[4];
124                        uint8_t         port[2];
125                } v4;
126                struct {
127                        uint8_t         addr[16];
128                        uint8_t         port[2];
129                } v6;
130        } u;
131};
132
133#define MP_ADD_ADDR_IPVER(sub_ipver)    (((sub_ipver) >> 0) & 0xF)
134
135struct mp_remove_addr {
136        uint8_t        kind;
137        uint8_t        len;
138        uint8_t        sub;
139        /* list of addr_id */
140        uint8_t        addrs_id;
141};
142
143struct mp_fail {
144        uint8_t        kind;
145        uint8_t        len;
146        uint8_t        sub;
147        uint8_t        resv;
148        uint8_t        data_seq[8];
149};
150
151struct mp_close {
152        uint8_t        kind;
153        uint8_t        len;
154        uint8_t        sub;
155        uint8_t        rsv;
156        uint8_t        key[8];
157};
158
159struct mp_prio {
160        uint8_t        kind;
161        uint8_t        len;
162        uint8_t        sub_b;
163        uint8_t        addr_id;
164};
165
166#define MP_PRIO_B                       0x01
167
168static int
169dummy_print(netdissect_options *ndo _U_,
170            const u_char *opt _U_, u_int opt_len _U_, u_char flags _U_)
171{
172        return 1;
173}
174
175static int
176mp_capable_print(netdissect_options *ndo,
177                 const u_char *opt, u_int opt_len, u_char flags)
178{
179        const struct mp_capable *mpc = (const struct mp_capable *) opt;
180
181        if (!(opt_len == 12 && (flags & TH_SYN)) &&
182            !(opt_len == 20 && (flags & (TH_SYN | TH_ACK)) == TH_ACK))
183                return 0;
184
185        if (MP_CAPABLE_OPT_VERSION(mpc->sub_ver) != 0) {
186                ND_PRINT((ndo, " Unknown Version (%d)", MP_CAPABLE_OPT_VERSION(mpc->sub_ver)));
187                return 1;
188        }
189
190        if (mpc->flags & MP_CAPABLE_C)
191                ND_PRINT((ndo, " csum"));
192        ND_PRINT((ndo, " {0x%" PRIx64, EXTRACT_64BITS(mpc->sender_key)));
193        if (opt_len == 20) /* ACK */
194                ND_PRINT((ndo, ",0x%" PRIx64, EXTRACT_64BITS(mpc->receiver_key)));
195        ND_PRINT((ndo, "}"));
196        return 1;
197}
198
199static int
200mp_join_print(netdissect_options *ndo,
201              const u_char *opt, u_int opt_len, u_char flags)
202{
203        const struct mp_join *mpj = (const struct mp_join *) opt;
204
205        if (!(opt_len == 12 && (flags & TH_SYN)) &&
206            !(opt_len == 16 && (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) &&
207            !(opt_len == 24 && (flags & TH_ACK)))
208                return 0;
209
210        if (opt_len != 24) {
211                if (mpj->sub_b & MP_JOIN_B)
212                        ND_PRINT((ndo, " backup"));
213                ND_PRINT((ndo, " id %u", mpj->addr_id));
214        }
215
216        switch (opt_len) {
217        case 12: /* SYN */
218                ND_PRINT((ndo, " token 0x%x" " nonce 0x%x",
219                        EXTRACT_32BITS(mpj->u.syn.token),
220                        EXTRACT_32BITS(mpj->u.syn.nonce)));
221                break;
222        case 16: /* SYN/ACK */
223                ND_PRINT((ndo, " hmac 0x%" PRIx64 " nonce 0x%x",
224                        EXTRACT_64BITS(mpj->u.synack.mac),
225                        EXTRACT_32BITS(mpj->u.synack.nonce)));
226                break;
227        case 24: {/* ACK */
228                size_t i;
229                ND_PRINT((ndo, " hmac 0x"));
230                for (i = 0; i < sizeof(mpj->u.ack.mac); ++i)
231                        ND_PRINT((ndo, "%02x", mpj->u.ack.mac[i]));
232        }
233        default:
234                break;
235        }
236        return 1;
237}
238
239static int
240mp_dss_print(netdissect_options *ndo,
241             const u_char *opt, u_int opt_len, u_char flags)
242{
243        const struct mp_dss *mdss = (const struct mp_dss *) opt;
244
245        /* We need the flags, at a minimum. */
246        if (opt_len < 4)
247                return 0;
248
249        if (flags & TH_SYN)
250                return 0;
251
252        if (mdss->flags & MP_DSS_F)
253                ND_PRINT((ndo, " fin"));
254
255        opt += 4;
256        opt_len -= 4;
257        if (mdss->flags & MP_DSS_A) {
258                /* Ack present */
259                ND_PRINT((ndo, " ack "));
260                /*
261                 * If the a flag is set, we have an 8-byte ack; if it's
262                 * clear, we have a 4-byte ack.
263                 */
264                if (mdss->flags & MP_DSS_a) {
265                        if (opt_len < 8)
266                                return 0;
267                        ND_PRINT((ndo, "%" PRIu64, EXTRACT_64BITS(opt)));
268                        opt += 8;
269                        opt_len -= 8;
270                } else {
271                        if (opt_len < 4)
272                                return 0;
273                        ND_PRINT((ndo, "%u", EXTRACT_32BITS(opt)));
274                        opt += 4;
275                        opt_len -= 4;
276                }
277        }
278
279        if (mdss->flags & MP_DSS_M) {
280                /*
281                 * Data Sequence Number (DSN), Subflow Sequence Number (SSN),
282                 * Data-Level Length present, and Checksum possibly present.
283                 */
284                ND_PRINT((ndo, " seq "));
285		/*
286                 * If the m flag is set, we have an 8-byte NDS; if it's clear,
287                 * we have a 4-byte DSN.
288                 */
289                if (mdss->flags & MP_DSS_m) {
290                        if (opt_len < 8)
291                                return 0;
292                        ND_PRINT((ndo, "%" PRIu64, EXTRACT_64BITS(opt)));
293                        opt += 8;
294                        opt_len -= 8;
295                } else {
296                        if (opt_len < 4)
297                                return 0;
298                        ND_PRINT((ndo, "%u", EXTRACT_32BITS(opt)));
299                        opt += 4;
300                        opt_len -= 4;
301                }
302                if (opt_len < 4)
303                        return 0;
304                ND_PRINT((ndo, " subseq %u", EXTRACT_32BITS(opt)));
305                opt += 4;
306                opt_len -= 4;
307                if (opt_len < 2)
308                        return 0;
309                ND_PRINT((ndo, " len %u", EXTRACT_16BITS(opt)));
310                opt += 2;
311                opt_len -= 2;
312
313                /*
314                 * The Checksum is present only if negotiated.
315                 * If there are at least 2 bytes left, process the next 2
316                 * bytes as the Checksum.
317                 */
318                if (opt_len >= 2) {
319                        ND_PRINT((ndo, " csum 0x%x", EXTRACT_16BITS(opt)));
320                        opt_len -= 2;
321                }
322        }
323        if (opt_len != 0)
324                return 0;
325        return 1;
326}
327
328static int
329add_addr_print(netdissect_options *ndo,
330               const u_char *opt, u_int opt_len, u_char flags _U_)
331{
332        const struct mp_add_addr *add_addr = (const struct mp_add_addr *) opt;
333        u_int ipver = MP_ADD_ADDR_IPVER(add_addr->sub_ipver);
334
335        if (!((opt_len == 8 || opt_len == 10) && ipver == 4) &&
336            !((opt_len == 20 || opt_len == 22) && ipver == 6))
337                return 0;
338
339        ND_PRINT((ndo, " id %u", add_addr->addr_id));
340        switch (ipver) {
341        case 4:
342                ND_PRINT((ndo, " %s", ipaddr_string(ndo, add_addr->u.v4.addr)));
343                if (opt_len == 10)
344                        ND_PRINT((ndo, ":%u", EXTRACT_16BITS(add_addr->u.v4.port)));
345                break;
346        case 6:
347                ND_PRINT((ndo, " %s", ip6addr_string(ndo, add_addr->u.v6.addr)));
348                if (opt_len == 22)
349                        ND_PRINT((ndo, ":%u", EXTRACT_16BITS(add_addr->u.v6.port)));
350                break;
351        default:
352                return 0;
353        }
354
355        return 1;
356}
357
358static int
359remove_addr_print(netdissect_options *ndo,
360                  const u_char *opt, u_int opt_len, u_char flags _U_)
361{
362        const struct mp_remove_addr *remove_addr = (const struct mp_remove_addr *) opt;
363        const uint8_t *addr_id = &remove_addr->addrs_id;
364
365        if (opt_len < 4)
366                return 0;
367
368        opt_len -= 3;
369        ND_PRINT((ndo, " id"));
370        while (opt_len--)
371                ND_PRINT((ndo, " %u", *addr_id++));
372        return 1;
373}
374
375static int
376mp_prio_print(netdissect_options *ndo,
377              const u_char *opt, u_int opt_len, u_char flags _U_)
378{
379        const struct mp_prio *mpp = (const struct mp_prio *) opt;
380
381        if (opt_len != 3 && opt_len != 4)
382                return 0;
383
384        if (mpp->sub_b & MP_PRIO_B)
385                ND_PRINT((ndo, " backup"));
386        else
387                ND_PRINT((ndo, " non-backup"));
388        if (opt_len == 4)
389                ND_PRINT((ndo, " id %u", mpp->addr_id));
390
391        return 1;
392}
393
394static int
395mp_fail_print(netdissect_options *ndo,
396              const u_char *opt, u_int opt_len, u_char flags _U_)
397{
398        if (opt_len != 12)
399                return 0;
400
401        ND_PRINT((ndo, " seq %" PRIu64, EXTRACT_64BITS(opt + 4)));
402        return 1;
403}
404
405static int
406mp_fast_close_print(netdissect_options *ndo,
407                    const u_char *opt, u_int opt_len, u_char flags _U_)
408{
409        if (opt_len != 12)
410                return 0;
411
412        ND_PRINT((ndo, " key 0x%" PRIx64, EXTRACT_64BITS(opt + 4)));
413        return 1;
414}
415
416static const struct {
417        const char *name;
418        int (*print)(netdissect_options *, const u_char *, u_int, u_char);
419} mptcp_options[] = {
420        { "capable", mp_capable_print},
421        { "join",       mp_join_print },
422        { "dss",        mp_dss_print },
423        { "add-addr",   add_addr_print },
424        { "rem-addr",   remove_addr_print },
425        { "prio",       mp_prio_print },
426        { "fail",       mp_fail_print },
427        { "fast-close", mp_fast_close_print },
428        { "unknown",    dummy_print },
429};
430
431int
432mptcp_print(netdissect_options *ndo,
433            const u_char *cp, u_int len, u_char flags)
434{
435        const struct mptcp_option *opt;
436        u_int subtype;
437
438        if (len < 3)
439                return 0;
440
441        opt = (const struct mptcp_option *) cp;
442        subtype = min(MPTCP_OPT_SUBTYPE(opt->sub_etc), MPTCP_SUB_FCLOSE + 1);
443
444        ND_PRINT((ndo, " %s", mptcp_options[subtype].name));
445        return mptcp_options[subtype].print(ndo, cp, len, flags);
446}
447