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 int verbose;
21 unsigned int queue_num;
22 unsigned int timeout;
23};
24
25static unsigned int queue_stats[5];
26static struct options opts;
27
28static void help(const char *p)
29{
30 printf("Usage: %s [-c|-v [-vv] ] [-t timeout] [-q queue_num]\n", p);
31}
32
33static int parse_attr_cb(const struct nlattr *attr, void *data)
34{
35 const struct nlattr **tb = data;
36 int type = mnl_attr_get_type(attr);
37
38
39 if (mnl_attr_type_valid(attr, NFQA_MAX) < 0)
40 return MNL_CB_OK;
41
42 switch (type) {
43 case NFQA_MARK:
44 case NFQA_IFINDEX_INDEV:
45 case NFQA_IFINDEX_OUTDEV:
46 case NFQA_IFINDEX_PHYSINDEV:
47 case NFQA_IFINDEX_PHYSOUTDEV:
48 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
49 perror("mnl_attr_validate");
50 return MNL_CB_ERROR;
51 }
52 break;
53 case NFQA_TIMESTAMP:
54 if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
55 sizeof(struct nfqnl_msg_packet_timestamp)) < 0) {
56 perror("mnl_attr_validate2");
57 return MNL_CB_ERROR;
58 }
59 break;
60 case NFQA_HWADDR:
61 if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
62 sizeof(struct nfqnl_msg_packet_hw)) < 0) {
63 perror("mnl_attr_validate2");
64 return MNL_CB_ERROR;
65 }
66 break;
67 case NFQA_PAYLOAD:
68 break;
69 }
70 tb[type] = attr;
71 return MNL_CB_OK;
72}
73
74static int queue_cb(const struct nlmsghdr *nlh, void *data)
75{
76 struct nlattr *tb[NFQA_MAX+1] = { 0 };
77 struct nfqnl_msg_packet_hdr *ph = NULL;
78 uint32_t id = 0;
79
80 (void)data;
81
82 mnl_attr_parse(nlh, sizeof(struct nfgenmsg), parse_attr_cb, tb);
83 if (tb[NFQA_PACKET_HDR]) {
84 ph = mnl_attr_get_payload(tb[NFQA_PACKET_HDR]);
85 id = ntohl(ph->packet_id);
86
87 if (opts.verbose > 0)
88 printf("packet hook=%u, hwproto 0x%x",
89 ntohs(ph->hw_protocol), ph->hook);
90
91 if (ph->hook >= 5) {
92 fprintf(stderr, "Unknown hook %d\n", ph->hook);
93 return MNL_CB_ERROR;
94 }
95
96 if (opts.verbose > 0) {
97 uint32_t skbinfo = 0;
98
99 if (tb[NFQA_SKB_INFO])
100 skbinfo = ntohl(mnl_attr_get_u32(tb[NFQA_SKB_INFO]));
101 if (skbinfo & NFQA_SKB_CSUMNOTREADY)
102 printf(" csumnotready");
103 if (skbinfo & NFQA_SKB_GSO)
104 printf(" gso");
105 if (skbinfo & NFQA_SKB_CSUM_NOTVERIFIED)
106 printf(" csumnotverified");
107 puts("");
108 }
109
110 if (opts.count_packets)
111 queue_stats[ph->hook]++;
112 }
113
114 return MNL_CB_OK + id;
115}
116
117static struct nlmsghdr *
118nfq_build_cfg_request(char *buf, uint8_t command, int queue_num)
119{
120 struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
121 struct nfqnl_msg_config_cmd cmd = {
122 .command = command,
123 .pf = htons(AF_INET),
124 };
125 struct nfgenmsg *nfg;
126
127 nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
128 nlh->nlmsg_flags = NLM_F_REQUEST;
129
130 nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
131
132 nfg->nfgen_family = AF_UNSPEC;
133 nfg->version = NFNETLINK_V0;
134 nfg->res_id = htons(queue_num);
135
136 mnl_attr_put(nlh, NFQA_CFG_CMD, sizeof(cmd), &cmd);
137
138 return nlh;
139}
140
141static struct nlmsghdr *
142nfq_build_cfg_params(char *buf, uint8_t mode, int range, int queue_num)
143{
144 struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
145 struct nfqnl_msg_config_params params = {
146 .copy_range = htonl(range),
147 .copy_mode = mode,
148 };
149 struct nfgenmsg *nfg;
150
151 nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_CONFIG;
152 nlh->nlmsg_flags = NLM_F_REQUEST;
153
154 nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
155 nfg->nfgen_family = AF_UNSPEC;
156 nfg->version = NFNETLINK_V0;
157 nfg->res_id = htons(queue_num);
158
159 mnl_attr_put(nlh, NFQA_CFG_PARAMS, sizeof(params), ¶ms);
160
161 return nlh;
162}
163
164static struct nlmsghdr *
165nfq_build_verdict(char *buf, int id, int queue_num, int verd)
166{
167 struct nfqnl_msg_verdict_hdr vh = {
168 .verdict = htonl(verd),
169 .id = htonl(id),
170 };
171 struct nlmsghdr *nlh;
172 struct nfgenmsg *nfg;
173
174 nlh = mnl_nlmsg_put_header(buf);
175 nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | NFQNL_MSG_VERDICT;
176 nlh->nlmsg_flags = NLM_F_REQUEST;
177 nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
178 nfg->nfgen_family = AF_UNSPEC;
179 nfg->version = NFNETLINK_V0;
180 nfg->res_id = htons(queue_num);
181
182 mnl_attr_put(nlh, NFQA_VERDICT_HDR, sizeof(vh), &vh);
183
184 return nlh;
185}
186
187static void print_stats(void)
188{
189 unsigned int last, total;
190 int i;
191
192 if (!opts.count_packets)
193 return;
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 = NFQA_CFG_F_GSO | NFQA_CFG_F_UID_GID;
238 mnl_attr_put_u32(nlh, NFQA_CFG_FLAGS, htonl(flags));
239 mnl_attr_put_u32(nlh, NFQA_CFG_MASK, htonl(flags));
240
241 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
242 perror("mnl_socket_sendto");
243 exit(EXIT_FAILURE);
244 }
245
246 memset(&tv, 0, sizeof(tv));
247 tv.tv_sec = opts.timeout;
248 if (opts.timeout && setsockopt(mnl_socket_get_fd(nl),
249 SOL_SOCKET, SO_RCVTIMEO,
250 &tv, sizeof(tv))) {
251 perror("setsockopt(SO_RCVTIMEO)");
252 exit(EXIT_FAILURE);
253 }
254
255 return nl;
256}
257
258static int mainloop(void)
259{
260 unsigned int buflen = 64 * 1024 + MNL_SOCKET_BUFFER_SIZE;
261 struct mnl_socket *nl;
262 struct nlmsghdr *nlh;
263 unsigned int portid;
264 char *buf;
265 int ret;
266
267 buf = malloc(buflen);
268 if (!buf) {
269 perror("malloc");
270 exit(EXIT_FAILURE);
271 }
272
273 nl = open_queue();
274 portid = mnl_socket_get_portid(nl);
275
276 for (;;) {
277 uint32_t id;
278
279 ret = mnl_socket_recvfrom(nl, buf, buflen);
280 if (ret == -1) {
281 if (errno == ENOBUFS)
282 continue;
283
284 if (errno == EAGAIN) {
285 errno = 0;
286 ret = 0;
287 break;
288 }
289
290 perror("mnl_socket_recvfrom");
291 exit(EXIT_FAILURE);
292 }
293
294 ret = mnl_cb_run(buf, ret, 0, portid, queue_cb, NULL);
295 if (ret < 0) {
296 perror("mnl_cb_run");
297 exit(EXIT_FAILURE);
298 }
299
300 id = ret - MNL_CB_OK;
301 nlh = nfq_build_verdict(buf, id, opts.queue_num, NF_ACCEPT);
302 if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
303 perror("mnl_socket_sendto");
304 exit(EXIT_FAILURE);
305 }
306 }
307
308 mnl_socket_close(nl);
309
310 return ret;
311}
312
313static void parse_opts(int argc, char **argv)
314{
315 int c;
316
317 while ((c = getopt(argc, argv, "chvt:q:")) != -1) {
318 switch (c) {
319 case 'c':
320 opts.count_packets = true;
321 break;
322 case 'h':
323 help(argv[0]);
324 exit(0);
325 break;
326 case 'q':
327 opts.queue_num = atoi(optarg);
328 if (opts.queue_num > 0xffff)
329 opts.queue_num = 0;
330 break;
331 case 't':
332 opts.timeout = atoi(optarg);
333 break;
334 case 'v':
335 opts.verbose++;
336 break;
337 }
338 }
339}
340
341int main(int argc, char *argv[])
342{
343 int ret;
344
345 parse_opts(argc, argv);
346
347 ret = mainloop();
348 if (opts.count_packets)
349 print_stats();
350
351 return ret;
352}
353
