1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <errno.h>
4 #include <stdbool.h>
5 #include <stdio.h>
6 #include <stdint.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <string.h>
10 #include <time.h>
11 #include <arpa/inet.h>
12
13 #include <libmnl/libmnl.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter/nfnetlink.h>
16 #include <linux/netfilter/nfnetlink_queue.h>
17
18 struct options {
19 bool count_packets;
20 bool gso_enabled;
21 bool failopen;
22 int verbose;
23 unsigned int queue_num;
24 unsigned int timeout;
25 uint32_t verdict;
26 uint32_t delay_ms;
27 };
28
29 static unsigned int queue_stats[5];
30 static struct options opts;
31
help(const char * p)32 static void help(const char *p)
33 {
34 printf("Usage: %s [-c|-v [-vv] ] [-o] [-t timeout] [-q queue_num] [-Qdst_queue ] [ -d ms_delay ] [-G]\n", p);
35 }
36
parse_attr_cb(const struct nlattr * attr,void * data)37 static int parse_attr_cb(const struct nlattr *attr, void *data)
38 {
39 const struct nlattr **tb = data;
40 int type = mnl_attr_get_type(attr);
41
42 /* skip unsupported attribute in user-space */
43 if (mnl_attr_type_valid(attr, NFQA_MAX) < 0)
44 return MNL_CB_OK;
45
46 switch (type) {
47 case NFQA_MARK:
48 case NFQA_IFINDEX_INDEV:
49 case NFQA_IFINDEX_OUTDEV:
50 case NFQA_IFINDEX_PHYSINDEV:
51 case NFQA_IFINDEX_PHYSOUTDEV:
52 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
53 perror("mnl_attr_validate");
54 return MNL_CB_ERROR;
55 }
56 break;
57 case NFQA_TIMESTAMP:
58 if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
59 sizeof(struct nfqnl_msg_packet_timestamp)) < 0) {
60 perror("mnl_attr_validate2");
61 return MNL_CB_ERROR;
62 }
63 break;
64 case NFQA_HWADDR:
65 if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
66 sizeof(struct nfqnl_msg_packet_hw)) < 0) {
67 perror("mnl_attr_validate2");
68 return MNL_CB_ERROR;
69 }
70 break;
71 case NFQA_PAYLOAD:
72 break;
73 }
74 tb[type] = attr;
75 return MNL_CB_OK;
76 }
77
queue_cb(const struct nlmsghdr * nlh,void * data)78 static int queue_cb(const struct nlmsghdr *nlh, void *data)
79 {
80 struct nlattr *tb[NFQA_MAX+1] = { 0 };
81 struct nfqnl_msg_packet_hdr *ph = NULL;
82 uint32_t id = 0;
83
84 (void)data;
85
86 mnl_attr_parse(nlh, sizeof(struct nfgenmsg), parse_attr_cb, tb);
87 if (tb[NFQA_PACKET_HDR]) {
88 ph = mnl_attr_get_payload(tb[NFQA_PACKET_HDR]);
89 id = ntohl(ph->packet_id);
90
91 if (opts.verbose > 0)
92 printf("packet hook=%u, hwproto 0x%x",
93 ntohs(ph->hw_protocol), ph->hook);
94
95 if (ph->hook >= 5) {
96 fprintf(stderr, "Unknown hook %d\n", ph->hook);
97 return MNL_CB_ERROR;
98 }
99
100 if (opts.verbose > 0) {
101 uint32_t skbinfo = 0;
102
103 if (tb[NFQA_SKB_INFO])
104 skbinfo = ntohl(mnl_attr_get_u32(tb[NFQA_SKB_INFO]));
105 if (skbinfo & NFQA_SKB_CSUMNOTREADY)
106 printf(" csumnotready");
107 if (skbinfo & NFQA_SKB_GSO)
108 printf(" gso");
109 if (skbinfo & NFQA_SKB_CSUM_NOTVERIFIED)
110 printf(" csumnotverified");
111 puts("");
112 }
113
114 if (opts.count_packets)
115 queue_stats[ph->hook]++;
116 }
117
118 return MNL_CB_OK + id;
119 }
120
121 static struct nlmsghdr *
nfq_build_cfg_request(char * buf,uint8_t command,int queue_num)122 nfq_build_cfg_request(char *buf, uint8_t command, int queue_num)
123 {
124 struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
125 struct nfqnl_msg_config_cmd cmd = {
126 .command = command,
127 .pf = htons(AF_INET),
128 };
129 struct nfgenmsg *nfg;
130
131 nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
132 nlh->nlmsg_flags = NLM_F_REQUEST;
133
134 nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
135
136 nfg->nfgen_family = AF_UNSPEC;
137 nfg->version = NFNETLINK_V0;
138 nfg->res_id = htons(queue_num);
139
140 mnl_attr_put(nlh, NFQA_CFG_CMD, sizeof(cmd), &cmd);
141
142 return nlh;
143 }
144
145 static struct nlmsghdr *
nfq_build_cfg_params(char * buf,uint8_t mode,int range,int queue_num)146 nfq_build_cfg_params(char *buf, uint8_t mode, int range, int queue_num)
147 {
148 struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
149 struct nfqnl_msg_config_params params = {
150 .copy_range = htonl(range),
151 .copy_mode = mode,
152 };
153 struct nfgenmsg *nfg;
154
155 nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
156 nlh->nlmsg_flags = NLM_F_REQUEST;
157
158 nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
159 nfg->nfgen_family = AF_UNSPEC;
160 nfg->version = NFNETLINK_V0;
161 nfg->res_id = htons(queue_num);
162
163 mnl_attr_put(nlh, NFQA_CFG_PARAMS, sizeof(params), ¶ms);
164
165 return nlh;
166 }
167
168 static struct nlmsghdr *
nfq_build_verdict(char * buf,int id,int queue_num,uint32_t verd)169 nfq_build_verdict(char *buf, int id, int queue_num, uint32_t verd)
170 {
171 struct nfqnl_msg_verdict_hdr vh = {
172 .verdict = htonl(verd),
173 .id = htonl(id),
174 };
175 struct nlmsghdr *nlh;
176 struct nfgenmsg *nfg;
177
178 nlh = mnl_nlmsg_put_header(buf);
179 nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT;
180 nlh->nlmsg_flags = NLM_F_REQUEST;
181 nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
182 nfg->nfgen_family = AF_UNSPEC;
183 nfg->version = NFNETLINK_V0;
184 nfg->res_id = htons(queue_num);
185
186 mnl_attr_put(nlh, NFQA_VERDICT_HDR, sizeof(vh), &vh);
187
188 return nlh;
189 }
190
print_stats(void)191 static void print_stats(void)
192 {
193 unsigned int last, total;
194 int i;
195
196 total = 0;
197 last = queue_stats[0];
198
199 for (i = 0; i < 5; i++) {
200 printf("hook %d packets %08u\n", i, queue_stats[i]);
201 last = queue_stats[i];
202 total += last;
203 }
204
205 printf("%u packets total\n", total);
206 }
207
open_queue(void)208 struct mnl_socket *open_queue(void)
209 {
210 char buf[MNL_SOCKET_BUFFER_SIZE];
211 unsigned int queue_num;
212 struct mnl_socket *nl;
213 struct nlmsghdr *nlh;
214 struct timeval tv;
215 uint32_t flags;
216
217 nl = mnl_socket_open(NETLINK_NETFILTER);
218 if (nl == NULL) {
219 perror("mnl_socket_open");
220 exit(EXIT_FAILURE);
221 }
222
223 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
224 perror("mnl_socket_bind");
225 exit(EXIT_FAILURE);
226 }
227
228 queue_num = opts.queue_num;
229 nlh = nfq_build_cfg_request(buf, NFQNL_CFG_CMD_BIND, queue_num);
230
231 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
232 perror("mnl_socket_sendto");
233 exit(EXIT_FAILURE);
234 }
235
236 nlh = nfq_build_cfg_params(buf, NFQNL_COPY_PACKET, 0xFFFF, queue_num);
237
238 flags = opts.gso_enabled ? NFQA_CFG_F_GSO : 0;
239 flags |= NFQA_CFG_F_UID_GID;
240 if (opts.failopen)
241 flags |= NFQA_CFG_F_FAIL_OPEN;
242 mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(flags));
243 mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(flags));
244
245 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
246 perror("mnl_socket_sendto");
247 exit(EXIT_FAILURE);
248 }
249
250 memset(&tv, 0, sizeof(tv));
251 tv.tv_sec = opts.timeout;
252 if (opts.timeout && setsockopt(mnl_socket_get_fd(nl),
253 SOL_SOCKET, SO_RCVTIMEO,
254 &tv, sizeof(tv))) {
255 perror("setsockopt(SO_RCVTIMEO)");
256 exit(EXIT_FAILURE);
257 }
258
259 return nl;
260 }
261
sleep_ms(uint32_t delay)262 static void sleep_ms(uint32_t delay)
263 {
264 struct timespec ts = { .tv_sec = delay / 1000 };
265
266 delay %= 1000;
267
268 ts.tv_nsec = delay * 1000llu * 1000llu;
269
270 nanosleep(&ts, NULL);
271 }
272
mainloop(void)273 static int mainloop(void)
274 {
275 unsigned int buflen = 64 * 1024 + MNL_SOCKET_BUFFER_SIZE;
276 struct mnl_socket *nl;
277 struct nlmsghdr *nlh;
278 unsigned int portid;
279 char *buf;
280 int ret;
281
282 buf = malloc(buflen);
283 if (!buf) {
284 perror("malloc");
285 exit(EXIT_FAILURE);
286 }
287
288 nl = open_queue();
289 portid = mnl_socket_get_portid(nl);
290
291 for (;;) {
292 uint32_t id;
293
294 ret = mnl_socket_recvfrom(nl, buf, buflen);
295 if (ret == -1) {
296 if (errno == ENOBUFS || errno == EINTR)
297 continue;
298
299 if (errno == EAGAIN) {
300 errno = 0;
301 ret = 0;
302 break;
303 }
304
305 perror("mnl_socket_recvfrom");
306 exit(EXIT_FAILURE);
307 }
308
309 ret = mnl_cb_run(buf, ret, 0, portid, queue_cb, NULL);
310 if (ret < 0) {
311 perror("mnl_cb_run");
312 exit(EXIT_FAILURE);
313 }
314
315 id = ret - MNL_CB_OK;
316 if (opts.delay_ms)
317 sleep_ms(opts.delay_ms);
318
319 nlh = nfq_build_verdict(buf, id, opts.queue_num, opts.verdict);
320 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
321 perror("mnl_socket_sendto");
322 exit(EXIT_FAILURE);
323 }
324 }
325
326 mnl_socket_close(nl);
327
328 return ret;
329 }
330
parse_opts(int argc,char ** argv)331 static void parse_opts(int argc, char **argv)
332 {
333 int c;
334
335 while ((c = getopt(argc, argv, "chvot:q:Q:d:G")) != -1) {
336 switch (c) {
337 case 'c':
338 opts.count_packets = true;
339 break;
340 case 'h':
341 help(argv[0]);
342 exit(0);
343 break;
344 case 'q':
345 opts.queue_num = atoi(optarg);
346 if (opts.queue_num > 0xffff)
347 opts.queue_num = 0;
348 break;
349 case 'Q':
350 opts.verdict = atoi(optarg);
351 if (opts.verdict > 0xffff) {
352 fprintf(stderr, "Expected destination queue number\n");
353 exit(1);
354 }
355
356 opts.verdict <<= 16;
357 opts.verdict |= NF_QUEUE;
358 break;
359 case 'd':
360 opts.delay_ms = atoi(optarg);
361 if (opts.delay_ms == 0) {
362 fprintf(stderr, "Expected nonzero delay (in milliseconds)\n");
363 exit(1);
364 }
365 break;
366 case 't':
367 opts.timeout = atoi(optarg);
368 break;
369 case 'G':
370 opts.gso_enabled = false;
371 break;
372 case 'o':
373 opts.failopen = true;
374 break;
375 case 'v':
376 opts.verbose++;
377 break;
378 }
379 }
380
381 if (opts.verdict != NF_ACCEPT && (opts.verdict >> 16 == opts.queue_num)) {
382 fprintf(stderr, "Cannot use same destination and source queue\n");
383 exit(1);
384 }
385 }
386
main(int argc,char * argv[])387 int main(int argc, char *argv[])
388 {
389 int ret;
390
391 opts.verdict = NF_ACCEPT;
392 opts.gso_enabled = true;
393
394 parse_opts(argc, argv);
395
396 ret = mainloop();
397 if (opts.count_packets)
398 print_stats();
399
400 return ret;
401 }
402