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