3
4/*
5 * Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19
20#include <syslog.h>
21
22#include <sys/ioctl.h>
23#include <sys/types.h>
24#include <sys/socket.h>
25
26#include <net/if.h>
27#include <net/pfvar.h>
28#include <netinet/in.h>
29#include <netinet/tcp.h>
30#include <arpa/inet.h>
31
32#include <err.h>
33#include <errno.h>
34#include <fcntl.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38#include <unistd.h>
39
40#include "filter.h"
41
42/* From netinet/in.h, but only _KERNEL_ gets them. */
43#define satosin(sa) ((struct sockaddr_in *)(sa))
44#define satosin6(sa) ((struct sockaddr_in6 *)(sa))
45
46enum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE };
47
48int prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *,
49 u_int16_t, u_int8_t);
50int server_lookup4(struct sockaddr_in *, struct sockaddr_in *,
51 struct sockaddr_in *, u_int8_t);
52int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *,
53 struct sockaddr_in6 *, u_int8_t);
54
55static struct pfioc_pooladdr pfp;
56static struct pfioc_rule pfr;
57static struct pfioc_trans pft;
58static struct pfioc_trans_e pfte[TRANS_SIZE];
59static int dev, rule_log;
60static char *qname;
61
62int
63add_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src,
64 struct sockaddr *dst, u_int16_t d_port, u_int8_t proto)
65{
66 if (!src || !dst || !d_port || !proto) {
67 errno = EINVAL;
68 return (-1);
69 }
70
71 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port, proto) == -1)
72 return (-1);
73
74 pfr.rule.direction = dir;
75 if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
76 return (-1);
77
78 return (0);
79}
80
81int
82add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst,
83 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low,
84 u_int16_t nat_range_high, u_int8_t proto)
85{
86 if (!src || !dst || !d_port || !nat || !nat_range_low || !proto ||
87 (src->sa_family != nat->sa_family)) {
88 errno = EINVAL;
89 return (-1);
90 }
91
92 if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port, proto) == -1)
93 return (-1);
94
95 if (nat->sa_family == AF_INET) {
96 memcpy(&pfp.addr.addr.v.a.addr.v4,
97 &satosin(nat)->sin_addr.s_addr, 4);
98 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4);
99 } else {
100 memcpy(&pfp.addr.addr.v.a.addr.v6,
101 &satosin6(nat)->sin6_addr.s6_addr, 16);
102 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16);
103 }
104 if (ioctl(dev, DIOCADDADDR, &pfp) == -1)
105 return (-1);
106
107 pfr.rule.rpool.proxy_port[0] = nat_range_low;
108 pfr.rule.rpool.proxy_port[1] = nat_range_high;
109 if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
110 return (-1);
111
112 return (0);
113}
114
115int
116add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst,
117 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port, u_int8_t proto)
118{
119 if (!src || !dst || !d_port || !rdr || !rdr_port || !proto ||
120 (src->sa_family != rdr->sa_family)) {
121 errno = EINVAL;
122 return (-1);
123 }
124
125 if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port, proto) == -1)
126 return (-1);
127
128 if (rdr->sa_family == AF_INET) {
129 memcpy(&pfp.addr.addr.v.a.addr.v4,
130 &satosin(rdr)->sin_addr.s_addr, 4);
131 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4);
132 } else {
133 memcpy(&pfp.addr.addr.v.a.addr.v6,
134 &satosin6(rdr)->sin6_addr.s6_addr, 16);
135 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16);
136 }
137 if (ioctl(dev, DIOCADDADDR, &pfp) == -1)
138 return (-1);
139
140 pfr.rule.rpool.proxy_port[0] = rdr_port;
141 if (ioctl(dev, DIOCADDRULE, &pfr) == -1)
142 return (-1);
143
144 return (0);
145}
146
147int
148do_commit(void)
149{
150 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1)
151 return (-1);
152
153 return (0);
154}
155
156int
157do_rollback(void)
158{
159 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1)
160 return (-1);
161
162 return (0);
163}
164
165void
166init_filter(char *opt_qname, int opt_verbose)
167{
168 struct pf_status status;
169
170 qname = opt_qname;
171
172 if (opt_verbose == 1)
173 rule_log = PF_LOG;
174 else if (opt_verbose == 2)
175 rule_log = PF_LOG_ALL;
176
177 dev = open("/dev/pf", O_RDWR);
178 if (dev == -1) {
179 syslog(LOG_ERR, "can't open /dev/pf");
180 exit(1);
181 }
182 if (ioctl(dev, DIOCGETSTATUS, &status) == -1) {
183 syslog(LOG_ERR, "DIOCGETSTATUS");
184 exit(1);
185 }
186 if (!status.running) {
187 syslog(LOG_ERR, "pf is disabled");
188 exit(1);
189 }
190}
191
192int
193prepare_commit(u_int32_t id)
194{
195 char an[PF_ANCHOR_NAME_SIZE];
196 int i;
197
198 memset(&pft, 0, sizeof pft);
199 pft.size = TRANS_SIZE;
200 pft.esize = sizeof pfte[0];
201 pft.array = pfte;
202
203 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
204 getpid(), id);
205 for (i = 0; i < TRANS_SIZE; i++) {
206 memset(&pfte[i], 0, sizeof pfte[0]);
207 strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE);
208 switch (i) {
209 case TRANS_FILTER:
210 pfte[i].rs_num = PF_RULESET_FILTER;
211 break;
212 case TRANS_NAT:
213 pfte[i].rs_num = PF_RULESET_NAT;
214 break;
215 case TRANS_RDR:
216 pfte[i].rs_num = PF_RULESET_RDR;
217 break;
218 default:
219 errno = EINVAL;
220 return (-1);
221 }
222 }
223
224 if (ioctl(dev, DIOCXBEGIN, &pft) == -1)
225 return (-1);
226
227 return (0);
228}
229
230int
231prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src,
232 struct sockaddr *dst, u_int16_t d_port, u_int8_t proto)
233{
234 char an[PF_ANCHOR_NAME_SIZE];
235
236 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) ||
237 (src->sa_family != dst->sa_family)) {
238 errno = EPROTONOSUPPORT;
239 return (-1);
240 }
241
242 memset(&pfp, 0, sizeof pfp);
243 memset(&pfr, 0, sizeof pfr);
244 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR,
245 getpid(), id);
246 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE);
247 strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE);
248
249 switch (rs_num) {
250 case PF_RULESET_FILTER:
251 pfr.ticket = pfte[TRANS_FILTER].ticket;
252 break;
253 case PF_RULESET_NAT:
254 pfr.ticket = pfte[TRANS_NAT].ticket;
255 break;
256 case PF_RULESET_RDR:
257 pfr.ticket = pfte[TRANS_RDR].ticket;
258 break;
259 default:
260 errno = EINVAL;
261 return (-1);
262 }
263 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1)
264 return (-1);
265 pfr.pool_ticket = pfp.ticket;
266
267 /* Generic for all rule types. */
268 pfr.rule.af = src->sa_family;
269 pfr.rule.proto = proto;
270 pfr.rule.src.addr.type = PF_ADDR_ADDRMASK;
271 pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK;
272 if (src->sa_family == AF_INET) {
273 memcpy(&pfr.rule.src.addr.v.a.addr.v4,
274 &satosin(src)->sin_addr.s_addr, 4);
275 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4);
276 memcpy(&pfr.rule.dst.addr.v.a.addr.v4,
277 &satosin(dst)->sin_addr.s_addr, 4);
278 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4);
279 } else {
280 memcpy(&pfr.rule.src.addr.v.a.addr.v6,
281 &satosin6(src)->sin6_addr.s6_addr, 16);
282 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16);
283 memcpy(&pfr.rule.dst.addr.v.a.addr.v6,
284 &satosin6(dst)->sin6_addr.s6_addr, 16);
285 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16);
286 }
287 pfr.rule.dst.port_op = PF_OP_EQ;
288 pfr.rule.dst.port[0] = htons(d_port);
289
290 switch (rs_num) {
291 case PF_RULESET_FILTER:
292 /*
293 * pass quick [log] inet[6] proto tcp \
294 * from $src to $dst port = $d_port flags S/SAFR keep state
295 * (max 1) [queue qname]
296 */
297 pfr.rule.action = PF_PASS;
298 pfr.rule.quick = 1;
299 pfr.rule.log = rule_log;
300 pfr.rule.keep_state = 1;
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310 pfr.rule.max_states = 1;
311 if (qname != NULL)
312 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname);
313 break;
314 case PF_RULESET_NAT:
315 /*
316 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat
317 */
318 pfr.rule.action = PF_NAT;
319 break;
320 case PF_RULESET_RDR:
321 /*
322 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr
323 */
324 pfr.rule.action = PF_RDR;
325 break;
326 default:
327 errno = EINVAL;
328 return (-1);
329 }
330
331 return (0);
332}
333
334int
335server_lookup(struct sockaddr *client, struct sockaddr *proxy,
336 struct sockaddr *server, u_int8_t proto)
337{
338 if (client->sa_family == AF_INET)
339 return (server_lookup4(satosin(client), satosin(proxy),
340 satosin(server), proto));
341
342 if (client->sa_family == AF_INET6)
343 return (server_lookup6(satosin6(client), satosin6(proxy),
344 satosin6(server), proto));
345
346 errno = EPROTONOSUPPORT;
347 return (-1);
348}
349
350int
351server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy,
352 struct sockaddr_in *server, u_int8_t proto)
353{
354 struct pfioc_natlook pnl;
355
356 memset(&pnl, 0, sizeof pnl);
357 pnl.direction = PF_OUT;
358 pnl.af = AF_INET;
359 pnl.proto = proto;
360 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4);
361 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4);
362 pnl.sport = client->sin_port;
363 pnl.dport = proxy->sin_port;
364
365 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1)
366 return (-1);
367
368 memset(server, 0, sizeof(struct sockaddr_in));
369 server->sin_len = sizeof(struct sockaddr_in);
370 server->sin_family = AF_INET;
371 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4,
372 sizeof server->sin_addr.s_addr);
373 server->sin_port = pnl.rdport;
374
375 return (0);
376}
377
378int
379server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy,
380 struct sockaddr_in6 *server, u_int8_t proto)
381{
382 struct pfioc_natlook pnl;
383
384 memset(&pnl, 0, sizeof pnl);
385 pnl.direction = PF_OUT;
386 pnl.af = AF_INET6;
387 pnl.proto = proto;
388 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6);
389 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6);
390 pnl.sport = client->sin6_port;
391 pnl.dport = proxy->sin6_port;
392
393 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1)
394 return (-1);
395
396 memset(server, 0, sizeof(struct sockaddr_in6));
397 server->sin6_len = sizeof(struct sockaddr_in6);
398 server->sin6_family = AF_INET6;
399 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6,
400 sizeof server->sin6_addr);
401 server->sin6_port = pnl.rdport;
402
403 return (0);
404}
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