summaryrefslogtreecommitdiff
path: root/sys/net/npf/npf_connkey.c
blob: 021526e33322e27f814ab7333c131ddfda89aa80 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
/*-
 * Copyright (c) 2014-2020 Mindaugas Rasiukevicius <rmind at netbsd org>
 * Copyright (c) 2010-2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This material is based upon work partially supported by The
 * NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Connection key -- is an n-tuple structure encoding the address length,
 * layer 3 protocol, source and destination addresses and ports (or other
 * protocol IDs) and some configurable elements (see below).
 *
 * Key layout
 *
 *	The single key is formed out of 32-bit integers.  The layout is
 *	as follows (first row -- fields, second row -- number of bits):
 *
 *	| alen | proto |  ckey  | src-id | dst-id | src-addr | dst-addr |
 *	+------+-------+--------+--------+--------+----------+----------+
 *	|   4  |   8   |   20   |   16   |   16   |  32-128  |  32-128  |
 *
 *	The source and destination are inverted if the key is for the
 *	backwards stream (NPF_FLOW_BACK).  The address length depends on
 *	the 'alen' field.  The length is in words and is either 1 or 4,
 *	meaning 4 or 16 in bytes.
 *
 *	The 20-bit configurable key area ('ckey') is for the optional
 *	elements which may be included or excluded by the user.  It has
 *	the following layout:
 *
 *	| direction | interface-id |
 *	+-----------+--------------+
 *	|     2     |      18      |
 *
 *	Note: neither direction nor interface ID cannot be zero; we rely
 *	on this by reserving the zero 'ckey' value to for the case when
 *	these checks are not applicable.
 *
 * Embedding in the connection structure (npf_conn_t)
 *
 *	Two keys are stored in the npf_conn_t::c_keys[] array, which is
 *	variable-length, depending on whether the keys store IPv4 or IPv6
 *	addresses.  The length of the first key determines the position
 *	of the second key.
 *
 * WARNING: the keys must be immutable while they are in conndb.
 */

#ifdef _KERNEL
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: npf_connkey.c,v 1.2 2020/05/30 14:16:56 rmind Exp $");

#include <sys/param.h>
#include <sys/types.h>
#endif

#define __NPF_CONN_PRIVATE
#include "npf_conn.h"
#include "npf_impl.h"

unsigned
npf_connkey_setkey(npf_connkey_t *key, unsigned alen, unsigned proto,
    const void *ipv, const uint16_t *id, const npf_flow_t flow)
{
	const npf_addr_t * const *ips = ipv;
	uint32_t *k = key->ck_key;
	unsigned isrc, idst;

	if (__predict_true(flow == NPF_FLOW_FORW)) {
		isrc = NPF_SRC, idst = NPF_DST;
	} else {
		isrc = NPF_DST, idst = NPF_SRC;
	}

	/*
	 * See the key layout explanation above.
	 */
	KASSERT((alen >> 2) <= 0xf && proto <= 0xff);
	k[0] = ((uint32_t)(alen >> 2) << 28) | (proto << 20);
	k[1] = ((uint32_t)id[isrc] << 16) | id[idst];

	if (__predict_true(alen == sizeof(in_addr_t))) {
		k[2] = ips[isrc]->word32[0];
		k[3] = ips[idst]->word32[0];
		return 4 * sizeof(uint32_t);
	} else {
		const unsigned nwords = alen >> 2;
		memcpy(&k[2], ips[isrc], alen);
		memcpy(&k[2 + nwords], ips[idst], alen);
		return (2 + (nwords * 2)) * sizeof(uint32_t);
	}
}

void
npf_connkey_getkey(const npf_connkey_t *key, unsigned *alen, unsigned *proto,
    npf_addr_t *ips, uint16_t *id)
{
	const uint32_t *k = key->ck_key;

	/*
	 * See the key layout explanation above.
	 */

	*alen = (k[0] >> 28) << 2;
	*proto = (k[0] >> 16) & 0xff;
	id[NPF_SRC] = k[1] >> 16;
	id[NPF_DST] = k[1] & 0xffff;

	switch (*alen) {
	case sizeof(struct in6_addr):
	case sizeof(struct in_addr):
		memcpy(&ips[NPF_SRC], &k[2], *alen);
		memcpy(&ips[NPF_DST], &k[2 + ((unsigned)*alen >> 2)], *alen);
		return;
	default:
		KASSERT(0);
	}
}

static inline void
npf_connkey_setckey(npf_connkey_t *key, unsigned ifid, unsigned di)
{
	if (ifid) {
		/*
		 * Interface ID: the lower 18 bits of the 20-bit 'ckey'.
		 * Note: the interface ID cannot be zero.
		 */
		CTASSERT(NPF_MAX_IFMAP < (1U << 18));
		key->ck_key[0] |= ifid;
	}
	if (di) {
		/*
		 * Direction: The highest 2 bits of the 20-bit 'ckey'.
		 * Note: we rely on PFIL_IN and PFIL_OUT definitions.
		 */
		CTASSERT(PFIL_IN == 0x1 || PFIL_OUT == 0x2);
		KASSERT((di & ~PFIL_ALL) == 0);
		key->ck_key[0] |= ((uint32_t)di << 18);
	}
}

static void
npf_connkey_getckey(const npf_connkey_t *key, unsigned *ifid, unsigned *di)
{
	const uint32_t * const k = key->ck_key;

	*ifid = k[0] & ((1U << 20) - 1);
	*di = (k[0] >> 18) & PFIL_ALL;
}

/*
 * npf_conn_adjkey: adjust the connection key by setting the address/port.
 *
 * => The 'which' must either be NPF_SRC or NPF_DST.
 */
void
npf_conn_adjkey(npf_connkey_t *key, const npf_addr_t *naddr,
    const uint16_t id, const unsigned which)
{
	const unsigned alen = NPF_CONNKEY_ALEN(key);
	uint32_t * const k = key->ck_key;
	uint32_t *addr = &k[2 + ((alen >> 2) * which)];

	KASSERT(which == NPF_SRC || which == NPF_DST);
	KASSERT(alen > 0);
	memcpy(addr, naddr, alen);

	if (id) {
		const uint32_t oid = k[1];
		const unsigned shift = 16 * !which;
		const uint32_t mask = 0xffff0000 >> shift;
		k[1] = ((uint32_t)id << shift) | (oid & mask);
	}
}

static unsigned
npf_connkey_copy(const npf_connkey_t *skey, npf_connkey_t *dkey, bool invert)
{
	const unsigned klen = NPF_CONNKEY_LEN(skey);
	const uint32_t *sk = skey->ck_key;
	uint32_t *dk = dkey->ck_key;

	if (invert) {
		const unsigned alen = NPF_CONNKEY_ALEN(skey);
		const unsigned nwords = alen >> 2;

		dk[0] = sk[1];
		dk[1] = (sk[1] >> 16) | (sk[1] << 16);
		memcpy(&dk[2], &sk[2 + nwords], alen);
		memcpy(&dk[2 + nwords], &sk[2], alen);
	} else {
		memcpy(dk, sk, klen);
	}
	return klen;
}

/*
 * npf_conn_conkey: construct a key for the connection lookup.
 *
 * => Returns the key length in bytes or zero on failure.
 */
unsigned
npf_conn_conkey(const npf_cache_t *npc, npf_connkey_t *key,
    const unsigned di, const npf_flow_t flow)
{
	const npf_conn_params_t *params = npc->npc_ctx->params[NPF_PARAMS_CONN];
	const nbuf_t *nbuf = npc->npc_nbuf;
	const unsigned proto = npc->npc_proto;
	const unsigned alen = npc->npc_alen;
	const struct tcphdr *th;
	const struct udphdr *uh;
	uint16_t id[2] = { 0, 0 };
	unsigned ret;

	if (npc->npc_ckey) {
		/*
		 * Request to override the connection key.
		 */
		const bool invert = flow != NPF_FLOW_FORW;
		return npf_connkey_copy(npc->npc_ckey, key, invert);
	}

	switch (proto) {
	case IPPROTO_TCP:
		KASSERT(npf_iscached(npc, NPC_TCP));
		th = npc->npc_l4.tcp;
		id[NPF_SRC] = th->th_sport;
		id[NPF_DST] = th->th_dport;
		break;
	case IPPROTO_UDP:
		KASSERT(npf_iscached(npc, NPC_UDP));
		uh = npc->npc_l4.udp;
		id[NPF_SRC] = uh->uh_sport;
		id[NPF_DST] = uh->uh_dport;
		break;
	case IPPROTO_ICMP:
		if (npf_iscached(npc, NPC_ICMP_ID)) {
			const struct icmp *ic = npc->npc_l4.icmp;
			id[NPF_SRC] = ic->icmp_id;
			id[NPF_DST] = ic->icmp_id;
			break;
		}
		return 0;
	case IPPROTO_ICMPV6:
		if (npf_iscached(npc, NPC_ICMP_ID)) {
			const struct icmp6_hdr *ic6 = npc->npc_l4.icmp6;
			id[NPF_SRC] = ic6->icmp6_id;
			id[NPF_DST] = ic6->icmp6_id;
			break;
		}
		return 0;
	default:
		/* Unsupported protocol. */
		return 0;
	}

	ret = npf_connkey_setkey(key, alen, proto, npc->npc_ips, id, flow);
	npf_connkey_setckey(key,
	    params->connkey_interface ? nbuf->nb_ifid : 0,
	    params->connkey_direction ? (di & PFIL_ALL) : 0);
	return ret;
}

/*
 * npf_conn_getforwkey: get the address to the "forwards" key.
 */
npf_connkey_t *
npf_conn_getforwkey(npf_conn_t *conn)
{
	return (void *)&conn->c_keys[0];
}

/*
 * npf_conn_getbackkey: get the address to the "backwards" key.
 *
 * => It depends on the address length.
 */
npf_connkey_t *
npf_conn_getbackkey(npf_conn_t *conn, unsigned alen)
{
	const unsigned off = 2 + ((alen * 2) >> 2);
	KASSERT(off == NPF_CONNKEY_V4WORDS || off == NPF_CONNKEY_V6WORDS);
	return (void *)&conn->c_keys[off];
}

/*
 * Connection key exporting/importing.
 */

nvlist_t *
npf_connkey_export(npf_t *npf, const npf_connkey_t *key)
{
	unsigned alen, proto, ifid, di;
	npf_addr_t ips[2];
	uint16_t ids[2];
	nvlist_t *key_nv;

	key_nv = nvlist_create(0);

	npf_connkey_getkey(key, &alen, &proto, ips, ids);
	nvlist_add_number(key_nv, "proto", proto);
	nvlist_add_number(key_nv, "sport", ids[NPF_SRC]);
	nvlist_add_number(key_nv, "dport", ids[NPF_DST]);
	nvlist_add_binary(key_nv, "saddr", &ips[NPF_SRC], alen);
	nvlist_add_binary(key_nv, "daddr", &ips[NPF_DST], alen);

	npf_connkey_getckey(key, &ifid, &di);
	if (ifid) {
		char ifname[IFNAMSIZ];
		npf_ifmap_copyname(npf, ifid, ifname, sizeof(ifname));
		nvlist_add_string(key_nv, "ifname", ifname);
	}
	if (di) {
		nvlist_add_number(key_nv, "di", di);
	}

	return key_nv;
}

unsigned
npf_connkey_import(npf_t *npf, const nvlist_t *key_nv, npf_connkey_t *key)
{
	npf_addr_t const * ips[2];
	size_t alen1, alen2, proto;
	unsigned ret, di, ifid = 0;
	const char *ifname;
	uint16_t ids[2];

	proto = dnvlist_get_number(key_nv, "proto", 0);
	if (proto >= IPPROTO_MAX) {
		return 0;
	}
	ids[NPF_SRC] = dnvlist_get_number(key_nv, "sport", 0);
	ids[NPF_DST] = dnvlist_get_number(key_nv, "dport", 0);
	ips[NPF_SRC] = dnvlist_get_binary(key_nv, "saddr", &alen1, NULL, 0);
	ips[NPF_DST] = dnvlist_get_binary(key_nv, "daddr", &alen2, NULL, 0);
	if (alen1 == 0 || alen1 > sizeof(npf_addr_t) || alen1 != alen2) {
		return 0;
	}
	ret = npf_connkey_setkey(key, alen1, proto, ips, ids, NPF_FLOW_FORW);
	if (ret == 0) {
		return 0;
	}

	ifname = dnvlist_get_string(key_nv, "ifname", NULL);
	if (ifname && (ifid = npf_ifmap_register(npf, ifname)) == 0) {
		return 0;
	}
	di = dnvlist_get_number(key_nv, "di", 0) & PFIL_ALL;
	npf_connkey_setckey(key, ifid, di);

	return ret;
}

#if defined(DDB) || defined(_NPF_TESTING)

void
npf_connkey_print(const npf_connkey_t *key)
{
	unsigned alen, proto, ifid, di;
	npf_addr_t ips[2];
	uint16_t ids[2];

	npf_connkey_getkey(key, &alen, &proto, ips, ids);
	npf_connkey_getckey(key, &ifid, &di);
	printf("\tkey (ifid %u, di %x)\t", ifid, di);
	printf("%s:%u", npf_addr_dump(&ips[0], alen), ids[0]);
	printf("-> %s:%u\n", npf_addr_dump(&ips[1], alen), ids[1]);
}

#endif