/
socks.c
445 lines (395 loc) · 17.8 KB
/
socks.c
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
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
/* Copyright © 2014 Brandon L Black <blblack@gmail.com>
*
* This file is part of gdnsd.
*
* gdnsd 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 3 of the License, or
* (at your option) any later version.
*
* gdnsd 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 gdnsd. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
#include "socks.h"
#include "dnsio_udp.h"
#include "dnsio_tcp.h"
#include <gdnsd/alloc.h>
#include <gdnsd/misc.h>
#include <gdnsd/log.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>
// The "default defaults" for various address-level things
static const dns_addr_t addr_defs_defaults = {
.dns_port = 53U,
.udp_rcvbuf = 0U,
.udp_sndbuf = 0U,
.udp_threads = 2U,
.tcp_timeout = 37U,
.tcp_fastopen = 256U,
.tcp_clients_per_thread = 256U,
.tcp_backlog = 0U,
.tcp_threads = 2U,
.tcp_proxy = false,
.tcp_pad = false,
};
static const socks_cfg_t socks_cfg_defaults = {
.dns_addrs = NULL,
.dns_threads = NULL,
.ctl_addrs = NULL,
.num_dns_addrs = 0U,
.num_dns_threads = 0U,
.num_ctl_addrs = 0U,
.fd_estimate = 0LU,
};
// Generic iterator for catching bad config hash keys in various places below
F_NONNULL
static bool bad_key(const char* key, unsigned klen V_UNUSED, vscf_data_t* d V_UNUSED, const void* which_asvoid)
{
const char* which = which_asvoid;
log_fatal("Invalid %s key '%s'", which, key);
}
F_NONNULL
static void make_addr(const char* lspec_txt, const unsigned def_port, gdnsd_anysin_t* result)
{
const int addr_err = gdnsd_anysin_fromstr(lspec_txt, def_port, result);
if (addr_err)
log_fatal("Could not process listen-address spec '%s': %s", lspec_txt, gai_strerror(addr_err));
}
#define CFG_OPT_UINT_ALTSTORE(_opt_set, _gconf_loc, _min, _max, _store) \
do { \
vscf_data_t* _opt_setting = vscf_hash_get_data_byconstkey(_opt_set, #_gconf_loc, true); \
if (_opt_setting) { \
unsigned long _val; \
if (!vscf_is_simple(_opt_setting) \
|| !vscf_simple_get_as_ulong(_opt_setting, &_val)) \
log_fatal("Config option %s: Value must be a positive integer", #_gconf_loc); \
if (_val < _min || _val > _max) \
log_fatal("Config option %s: Value out of range (%lu, %lu)", #_gconf_loc, _min, _max); \
_store = (unsigned) _val; \
} \
} while (0)
#define CFG_OPT_UINT_ALTSTORE_NOMIN(_opt_set, _gconf_loc, _max, _store) \
do { \
vscf_data_t* _opt_setting = vscf_hash_get_data_byconstkey(_opt_set, #_gconf_loc, true); \
if (_opt_setting) { \
unsigned long _val; \
if (!vscf_is_simple(_opt_setting) \
|| !vscf_simple_get_as_ulong(_opt_setting, &_val)) \
log_fatal("Config option %s: Value must be a positive integer", #_gconf_loc); \
if (_val > _max) \
log_fatal("Config option %s: Value out of range (0, %lu)", #_gconf_loc, _max); \
_store = (unsigned) _val; \
} \
} while (0)
#define CFG_OPT_BOOL_ALTSTORE(_opt_set, _gconf_loc, _store) \
do { \
vscf_data_t* _opt_setting = vscf_hash_get_data_byconstkey(_opt_set, #_gconf_loc, true); \
if (_opt_setting) { \
bool _val; \
if (!vscf_is_simple(_opt_setting) \
|| !vscf_simple_get_as_bool(_opt_setting, &_val)) \
log_fatal("Config option %s: Value must be 'true' or 'false'", #_gconf_loc); \
_store = _val; \
} \
} while (0)
#define CFG_OPT_REMOVED(_opt_set, _gconf_loc) \
do { \
vscf_data_t* _opt_setting = vscf_hash_get_data_byconstkey(_opt_set, #_gconf_loc, true); \
if (_opt_setting) \
log_warn("Config option %s is no longer supported, and will become a syntax error in a future major version upgrade", #_gconf_loc); \
} while (0)
F_NONNULL
static void dns_listen_any(socks_cfg_t* socks_cfg, const dns_addr_t* addr_defs)
{
socks_cfg->num_dns_addrs = 2;
socks_cfg->dns_addrs = xcalloc_n(socks_cfg->num_dns_addrs, sizeof(*socks_cfg->dns_addrs));
dns_addr_t* ac_v4 = &socks_cfg->dns_addrs[0];
memcpy(ac_v4, addr_defs, sizeof(*ac_v4));
make_addr("0.0.0.0", addr_defs->dns_port, &ac_v4->addr);
dns_addr_t* ac_v6 = &socks_cfg->dns_addrs[1];
memcpy(ac_v6, addr_defs, sizeof(*ac_v6));
make_addr("::", addr_defs->dns_port, &ac_v6->addr);
}
F_NONNULL
static void process_listen_hashentry(dns_addr_t* addrconf, const char* lspec, vscf_data_t* addr_opts)
{
if (!vscf_is_hash(addr_opts))
log_fatal("DNS listen address '%s': per-address options must be a hash", lspec);
CFG_OPT_REMOVED(addr_opts, udp_recv_width);
CFG_OPT_BOOL_ALTSTORE(addr_opts, tcp_proxy, addrconf->tcp_proxy);
CFG_OPT_UINT_ALTSTORE(addr_opts, tcp_timeout, 5LU, 1800LU, addrconf->tcp_timeout);
CFG_OPT_UINT_ALTSTORE_NOMIN(addr_opts, tcp_fastopen, 1048576LU, addrconf->tcp_fastopen);
CFG_OPT_UINT_ALTSTORE(addr_opts, tcp_clients_per_thread, 16LU, 65535LU, addrconf->tcp_clients_per_thread);
CFG_OPT_UINT_ALTSTORE_NOMIN(addr_opts, tcp_backlog, 65535LU, addrconf->tcp_backlog);
CFG_OPT_UINT_ALTSTORE(addr_opts, tcp_threads, 1LU, 1024LU, addrconf->tcp_threads);
if (addrconf->tcp_proxy) {
addrconf->udp_threads = 0U;
addrconf->tcp_pad = true;
} else {
CFG_OPT_UINT_ALTSTORE(addr_opts, udp_rcvbuf, 4096LU, 1048576LU, addrconf->udp_rcvbuf);
CFG_OPT_UINT_ALTSTORE(addr_opts, udp_sndbuf, 4096LU, 1048576LU, addrconf->udp_sndbuf);
CFG_OPT_UINT_ALTSTORE(addr_opts, udp_threads, 1LU, 1024LU, addrconf->udp_threads);
}
CFG_OPT_BOOL_ALTSTORE(addr_opts, tcp_pad, addrconf->tcp_pad);
make_addr(lspec, addrconf->dns_port, &addrconf->addr);
if (addrconf->tcp_proxy) {
unsigned lport;
if (addrconf->addr.sa.sa_family == AF_INET) {
lport = addrconf->addr.sin4.sin_port;
} else {
gdnsd_assert(addrconf->addr.sa.sa_family == AF_INET6);
lport = addrconf->addr.sin6.sin6_port;
}
if (lport == 53U)
log_fatal("Cannot configure tcp_proxy mode on port 53");
}
vscf_hash_iterate_const(addr_opts, true, bad_key, addrconf->tcp_proxy
? "per-address listen option with tcp_proxy"
: "per-address listen option");
}
F_NONNULLX(1, 3)
static void fill_dns_addrs(socks_cfg_t* socks_cfg, vscf_data_t* listen_opt, const dns_addr_t* addr_defs)
{
if (!listen_opt) {
log_warn("Defaulting to listen=>any for lack of explicit listen config. Please explicitly configure it, as default behaviors may change in future releases!");
dns_listen_any(socks_cfg, addr_defs);
return;
}
if (vscf_is_simple(listen_opt)) {
const char* simple_str = vscf_simple_get_data(listen_opt);
if (!strcmp(simple_str, "any")) {
dns_listen_any(socks_cfg, addr_defs);
return;
}
}
if (vscf_is_hash(listen_opt)) {
socks_cfg->num_dns_addrs = vscf_hash_get_len(listen_opt);
socks_cfg->dns_addrs = xcalloc_n(socks_cfg->num_dns_addrs, sizeof(*socks_cfg->dns_addrs));
for (unsigned i = 0; i < socks_cfg->num_dns_addrs; i++) {
dns_addr_t* addrconf = &socks_cfg->dns_addrs[i];
memcpy(addrconf, addr_defs, sizeof(*addrconf));
const char* lspec = vscf_hash_get_key_byindex(listen_opt, i, NULL);
vscf_data_t* addr_opts = vscf_hash_get_data_byindex(listen_opt, i);
process_listen_hashentry(addrconf, lspec, addr_opts);
}
} else {
socks_cfg->num_dns_addrs = vscf_array_get_len(listen_opt);
socks_cfg->dns_addrs = xcalloc_n(socks_cfg->num_dns_addrs, sizeof(*socks_cfg->dns_addrs));
for (unsigned i = 0; i < socks_cfg->num_dns_addrs; i++) {
dns_addr_t* addrconf = &socks_cfg->dns_addrs[i];
memcpy(addrconf, addr_defs, sizeof(*addrconf));
vscf_data_t* lspec = vscf_array_get_data(listen_opt, i);
if (!vscf_is_simple(lspec))
log_fatal("Config option 'listen': all listen specs must be strings");
make_addr(vscf_simple_get_data(lspec), addr_defs->dns_port, &addrconf->addr);
}
}
}
F_NONNULLX(1, 3)
static void process_listen(socks_cfg_t* socks_cfg, vscf_data_t* listen_opt, const dns_addr_t* addr_defs)
{
// this fills in socks_cfg->dns_addrs raw data
fill_dns_addrs(socks_cfg, listen_opt, addr_defs);
if (!socks_cfg->num_dns_addrs)
log_fatal("DNS listen addresses explicitly configured as an empty set - cannot continue without at least one address!");
// use dns_addrs to populate dns_threads....
socks_cfg->num_dns_threads = 0;
for (unsigned i = 0; i < socks_cfg->num_dns_addrs; i++)
socks_cfg->num_dns_threads += (socks_cfg->dns_addrs[i].udp_threads + socks_cfg->dns_addrs[i].tcp_threads);
// Because we require thread counts to be non-zero
gdnsd_assert(socks_cfg->num_dns_threads);
socks_cfg->dns_threads = xcalloc_n(socks_cfg->num_dns_threads, sizeof(*socks_cfg->dns_threads));
unsigned tnum = 0;
for (unsigned i = 0; i < socks_cfg->num_dns_addrs; i++) {
dns_addr_t* a = &socks_cfg->dns_addrs[i];
for (unsigned j = 0; j < a->udp_threads; j++) {
dns_thread_t* t = &socks_cfg->dns_threads[tnum++];
t->ac = a;
t->is_udp = true;
t->sock = -1;
}
for (unsigned j = 0; j < a->tcp_threads; j++) {
dns_thread_t* t = &socks_cfg->dns_threads[tnum++];
t->ac = a;
t->is_udp = false;
t->sock = -1;
}
if (a->tcp_proxy) {
gdnsd_assert(!a->udp_threads);
log_info("DNS listener threads (%u TCP PROXY) configured for %s",
a->tcp_threads, logf_anysin(&a->addr));
} else {
log_info("DNS listener threads (%u UDP + %u TCP) configured for %s",
a->udp_threads, a->tcp_threads, logf_anysin(&a->addr));
}
}
gdnsd_assert(tnum == socks_cfg->num_dns_threads);
}
F_NONNULLX(1, 2)
static void process_control_item(ctl_addr_t* item, const char* lspec, vscf_data_t* addr_opts)
{
if (addr_opts) {
if (!vscf_is_hash(addr_opts))
log_fatal("Config option 'tcp_control': per-address config must be a hash");
CFG_OPT_BOOL_ALTSTORE(addr_opts, chal_ok, item->chal_ok);
CFG_OPT_BOOL_ALTSTORE(addr_opts, ctl_ok, item->ctl_ok);
vscf_hash_iterate_const(addr_opts, true, bad_key, "TCP Control Socket");
}
gdnsd_anysin_t* addr = &item->addr;
const int addr_err = gdnsd_anysin_fromstr(lspec, 0, addr);
if (addr_err)
log_fatal("Could not process tcp_control address spec '%s': %s", lspec, gai_strerror(addr_err));
unsigned lport = 0;
if (addr->sa.sa_family == AF_INET) {
lport = addr->sin4.sin_port;
} else {
gdnsd_assert(addr->sa.sa_family == AF_INET6);
lport = addr->sin6.sin6_port;
}
if (!lport)
log_fatal("Could not process tcp_control address spec '%s': port number required", lspec);
}
F_NONNULL
static void process_tcp_control(socks_cfg_t* socks_cfg, vscf_data_t* ctl_opt)
{
if (vscf_is_hash(ctl_opt)) {
socks_cfg->num_ctl_addrs = vscf_hash_get_len(ctl_opt);
if (!socks_cfg->num_ctl_addrs)
return;
socks_cfg->ctl_addrs = xcalloc_n(socks_cfg->num_ctl_addrs, sizeof(*socks_cfg->ctl_addrs));
for (unsigned i = 0; i < socks_cfg->num_ctl_addrs; i++) {
const char* lspec = vscf_hash_get_key_byindex(ctl_opt, i, NULL);
vscf_data_t* addr_opts = vscf_hash_get_data_byindex(ctl_opt, i);
process_control_item(&socks_cfg->ctl_addrs[i], lspec, addr_opts);
}
} else {
socks_cfg->num_ctl_addrs = vscf_array_get_len(ctl_opt);
if (!socks_cfg->num_ctl_addrs)
return;
socks_cfg->ctl_addrs = xcalloc_n(socks_cfg->num_ctl_addrs, sizeof(*socks_cfg->ctl_addrs));
for (unsigned i = 0; i < socks_cfg->num_ctl_addrs; i++) {
vscf_data_t* v_lspec = vscf_array_get_data(ctl_opt, i);
if (!vscf_is_simple(v_lspec))
log_fatal("Config option 'tcp_control': all listen specs must be strings");
process_control_item(&socks_cfg->ctl_addrs[i], vscf_simple_get_data(v_lspec), NULL);
}
}
}
socks_cfg_t* socks_conf_load(const vscf_data_t* cfg_root)
{
gdnsd_assert(!cfg_root || vscf_is_hash(cfg_root));
socks_cfg_t* socks_cfg = xmalloc(sizeof(*socks_cfg));
memcpy(socks_cfg, &socks_cfg_defaults, sizeof(*socks_cfg));
vscf_data_t* listen_opt = NULL;
vscf_data_t* ctl_opt = NULL;
dns_addr_t addr_defs;
memcpy(&addr_defs, &addr_defs_defaults, sizeof(addr_defs));
const vscf_data_t* options = cfg_root ? vscf_hash_get_data_byconstkey(cfg_root, "options", true) : NULL;
if (options) {
CFG_OPT_REMOVED(options, udp_recv_width);
CFG_OPT_UINT_ALTSTORE(options, dns_port, 1LU, 65535LU, addr_defs.dns_port);
CFG_OPT_UINT_ALTSTORE(options, udp_rcvbuf, 4096LU, 1048576LU, addr_defs.udp_rcvbuf);
CFG_OPT_UINT_ALTSTORE(options, udp_sndbuf, 4096LU, 1048576LU, addr_defs.udp_sndbuf);
CFG_OPT_UINT_ALTSTORE(options, udp_threads, 1LU, 1024LU, addr_defs.udp_threads);
CFG_OPT_UINT_ALTSTORE(options, tcp_timeout, 5LU, 1800LU, addr_defs.tcp_timeout);
CFG_OPT_UINT_ALTSTORE_NOMIN(options, tcp_fastopen, 1048576LU, addr_defs.tcp_fastopen);
CFG_OPT_UINT_ALTSTORE(options, tcp_clients_per_thread, 16LU, 65535LU, addr_defs.tcp_clients_per_thread);
CFG_OPT_UINT_ALTSTORE_NOMIN(options, tcp_backlog, 65535LU, addr_defs.tcp_backlog);
CFG_OPT_UINT_ALTSTORE(options, tcp_threads, 1LU, 1024LU, addr_defs.tcp_threads);
listen_opt = vscf_hash_get_data_byconstkey(options, "listen", true);
ctl_opt = vscf_hash_get_data_byconstkey(options, "tcp_control", true);
}
process_listen(socks_cfg, listen_opt, &addr_defs);
if (ctl_opt)
process_tcp_control(socks_cfg, ctl_opt);
// Estimate the number of socket fds needed, for later rlimit auto-tuning:
for (unsigned i = 0; i < socks_cfg->num_dns_addrs; i++) {
const dns_addr_t* da = &socks_cfg->dns_addrs[i];
socks_cfg->fd_estimate += da->udp_threads; // listener
socks_cfg->fd_estimate +=
(da->tcp_threads * (da->tcp_clients_per_thread + 5U));
// Note for TCP threads, there will be up to a few miscellaneous fds
// from the eventloop and polling mechanisms, separately from the
// listen socket, hence the constant "5" buffer there.
}
// There's no actual limit on client connections to control sockets, but
// let's estimate that 16 clients is enough for a default here.
socks_cfg->fd_estimate += (socks_cfg->num_ctl_addrs * 17U);
return socks_cfg;
}
void socks_bind_sock(const char* desc, const int sock, const gdnsd_anysin_t* sa)
{
int bind_errno = 0;
// Immediate, simple success
if (!bind(sock, &sa->sa, sa->len))
return;
bind_errno = errno;
#if defined IP_FREEBIND || (defined IP_BINDANY && defined IPV6_BINDANY) || defined SO_BINDANY
// first bind() attempt failed. in the case of non-ANY addresses, where
// the OS has support for freebind/bindany, try it before failing hard
if (errno == EADDRNOTAVAIL && !gdnsd_anysin_is_anyaddr(sa)) {
const int opt_one = 1;
# if defined IP_FREEBIND
// Linux
const int bindlev = IPPROTO_IP;
const int bindopt = IP_FREEBIND;
const char* bindtxt = "IP_FREEBIND";
# elif defined IP_BINDANY && defined IPV6_BINDANY
// FreeBSD, untested
const bool isv6 = sa->sa.sa_family == AF_INET6 ? true : false;
const int bindlev = isv6 ? IPPROTO_IPV6 : IPPROTO_IP;
const int bindopt = isv6 ? IPV6_BINDANY : IP_BINDANY;
const char* bindtxt = isv6 ? "IPV6_BINDANY" : "IP_BINDANY";
# elif defined SO_BINDANY
// OpenBSD equiv?
const int bindlev = SOL_SOCKET;
const int bindopt = SO_BINDANY;
const char* bindtxt = "SO_BINDANY";
# endif
if (setsockopt(sock, bindlev, bindopt, &opt_one, sizeof(opt_one)) == -1) {
// Don't even re-attempt the bind if we can't set the option, just
// warn about the setsockopt() and fail out at the bottom with the
// original errno from bind():
log_warn("Failed to set %s on %s socket %s: %s", bindtxt, desc, logf_anysin(sa), logf_errno());
} else {
if (!bind(sock, &sa->sa, sa->len)) {
// Success, after setting IP_FREEBIND or similar
log_warn("%s socket %s bound via %s, address may not (yet!) exist on the host", desc, logf_anysin(sa), bindtxt);
return;
}
// Second attempt failed, update bind_errno and fail out below
bind_errno = errno;
}
}
#endif
// If initial bind attempt failed, and the above freebind stuff either
// failed or isn't available, fail hard:
log_fatal("bind() failed for %s socket %s: %s", desc, logf_anysin(sa), logf_strerror(bind_errno));
}
void socks_dns_lsocks_init(socks_cfg_t* socks_cfg)
{
for (unsigned i = 0; i < socks_cfg->num_dns_threads; i++) {
dns_thread_t* t = &socks_cfg->dns_threads[i];
if (t->is_udp)
udp_sock_setup(t);
else
tcp_dns_listen_setup(t);
}
}