1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 // Copyright (C) 2018 Facebook
3
4 #define _GNU_SOURCE
5 #include <errno.h>
6 #include <fcntl.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <unistd.h>
10 #include <libbpf.h>
11 #include <net/if.h>
12 #include <linux/rtnetlink.h>
13 #include <linux/tc_act/tc_bpf.h>
14 #include <sys/socket.h>
15 #include <sys/stat.h>
16 #include <sys/types.h>
17
18 #include <bpf.h>
19 #include <nlattr.h>
20 #include "main.h"
21 #include "netlink_dumper.h"
22
23 struct ip_devname_ifindex {
24 char devname[64];
25 int ifindex;
26 };
27
28 struct bpf_netdev_t {
29 struct ip_devname_ifindex *devices;
30 int used_len;
31 int array_len;
32 int filter_idx;
33 };
34
35 struct tc_kind_handle {
36 char kind[64];
37 int handle;
38 };
39
40 struct bpf_tcinfo_t {
41 struct tc_kind_handle *handle_array;
42 int used_len;
43 int array_len;
44 bool is_qdisc;
45 };
46
47 struct bpf_filter_t {
48 const char *kind;
49 const char *devname;
50 int ifindex;
51 };
52
53 struct bpf_attach_info {
54 __u32 flow_dissector_id;
55 };
56
57 enum net_attach_type {
58 NET_ATTACH_TYPE_XDP,
59 NET_ATTACH_TYPE_XDP_GENERIC,
60 NET_ATTACH_TYPE_XDP_DRIVER,
61 NET_ATTACH_TYPE_XDP_OFFLOAD,
62 };
63
64 static const char * const attach_type_strings[] = {
65 [NET_ATTACH_TYPE_XDP] = "xdp",
66 [NET_ATTACH_TYPE_XDP_GENERIC] = "xdpgeneric",
67 [NET_ATTACH_TYPE_XDP_DRIVER] = "xdpdrv",
68 [NET_ATTACH_TYPE_XDP_OFFLOAD] = "xdpoffload",
69 };
70
71 const size_t net_attach_type_size = ARRAY_SIZE(attach_type_strings);
72
parse_attach_type(const char * str)73 static enum net_attach_type parse_attach_type(const char *str)
74 {
75 enum net_attach_type type;
76
77 for (type = 0; type < net_attach_type_size; type++) {
78 if (attach_type_strings[type] &&
79 is_prefix(str, attach_type_strings[type]))
80 return type;
81 }
82
83 return net_attach_type_size;
84 }
85
dump_link_nlmsg(void * cookie,void * msg,struct nlattr ** tb)86 static int dump_link_nlmsg(void *cookie, void *msg, struct nlattr **tb)
87 {
88 struct bpf_netdev_t *netinfo = cookie;
89 struct ifinfomsg *ifinfo = msg;
90
91 if (netinfo->filter_idx > 0 && netinfo->filter_idx != ifinfo->ifi_index)
92 return 0;
93
94 if (netinfo->used_len == netinfo->array_len) {
95 netinfo->devices = realloc(netinfo->devices,
96 (netinfo->array_len + 16) *
97 sizeof(struct ip_devname_ifindex));
98 if (!netinfo->devices)
99 return -ENOMEM;
100
101 netinfo->array_len += 16;
102 }
103 netinfo->devices[netinfo->used_len].ifindex = ifinfo->ifi_index;
104 snprintf(netinfo->devices[netinfo->used_len].devname,
105 sizeof(netinfo->devices[netinfo->used_len].devname),
106 "%s",
107 tb[IFLA_IFNAME]
108 ? libbpf_nla_getattr_str(tb[IFLA_IFNAME])
109 : "");
110 netinfo->used_len++;
111
112 return do_xdp_dump(ifinfo, tb);
113 }
114
dump_class_qdisc_nlmsg(void * cookie,void * msg,struct nlattr ** tb)115 static int dump_class_qdisc_nlmsg(void *cookie, void *msg, struct nlattr **tb)
116 {
117 struct bpf_tcinfo_t *tcinfo = cookie;
118 struct tcmsg *info = msg;
119
120 if (tcinfo->is_qdisc) {
121 /* skip clsact qdisc */
122 if (tb[TCA_KIND] &&
123 strcmp(libbpf_nla_data(tb[TCA_KIND]), "clsact") == 0)
124 return 0;
125 if (info->tcm_handle == 0)
126 return 0;
127 }
128
129 if (tcinfo->used_len == tcinfo->array_len) {
130 tcinfo->handle_array = realloc(tcinfo->handle_array,
131 (tcinfo->array_len + 16) * sizeof(struct tc_kind_handle));
132 if (!tcinfo->handle_array)
133 return -ENOMEM;
134
135 tcinfo->array_len += 16;
136 }
137 tcinfo->handle_array[tcinfo->used_len].handle = info->tcm_handle;
138 snprintf(tcinfo->handle_array[tcinfo->used_len].kind,
139 sizeof(tcinfo->handle_array[tcinfo->used_len].kind),
140 "%s",
141 tb[TCA_KIND]
142 ? libbpf_nla_getattr_str(tb[TCA_KIND])
143 : "unknown");
144 tcinfo->used_len++;
145
146 return 0;
147 }
148
dump_filter_nlmsg(void * cookie,void * msg,struct nlattr ** tb)149 static int dump_filter_nlmsg(void *cookie, void *msg, struct nlattr **tb)
150 {
151 const struct bpf_filter_t *filter_info = cookie;
152
153 return do_filter_dump((struct tcmsg *)msg, tb, filter_info->kind,
154 filter_info->devname, filter_info->ifindex);
155 }
156
show_dev_tc_bpf(int sock,unsigned int nl_pid,struct ip_devname_ifindex * dev)157 static int show_dev_tc_bpf(int sock, unsigned int nl_pid,
158 struct ip_devname_ifindex *dev)
159 {
160 struct bpf_filter_t filter_info;
161 struct bpf_tcinfo_t tcinfo;
162 int i, handle, ret = 0;
163
164 tcinfo.handle_array = NULL;
165 tcinfo.used_len = 0;
166 tcinfo.array_len = 0;
167
168 tcinfo.is_qdisc = false;
169 ret = libbpf_nl_get_class(sock, nl_pid, dev->ifindex,
170 dump_class_qdisc_nlmsg, &tcinfo);
171 if (ret)
172 goto out;
173
174 tcinfo.is_qdisc = true;
175 ret = libbpf_nl_get_qdisc(sock, nl_pid, dev->ifindex,
176 dump_class_qdisc_nlmsg, &tcinfo);
177 if (ret)
178 goto out;
179
180 filter_info.devname = dev->devname;
181 filter_info.ifindex = dev->ifindex;
182 for (i = 0; i < tcinfo.used_len; i++) {
183 filter_info.kind = tcinfo.handle_array[i].kind;
184 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex,
185 tcinfo.handle_array[i].handle,
186 dump_filter_nlmsg, &filter_info);
187 if (ret)
188 goto out;
189 }
190
191 /* root, ingress and egress handle */
192 handle = TC_H_ROOT;
193 filter_info.kind = "root";
194 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
195 dump_filter_nlmsg, &filter_info);
196 if (ret)
197 goto out;
198
199 handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS);
200 filter_info.kind = "clsact/ingress";
201 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
202 dump_filter_nlmsg, &filter_info);
203 if (ret)
204 goto out;
205
206 handle = TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS);
207 filter_info.kind = "clsact/egress";
208 ret = libbpf_nl_get_filter(sock, nl_pid, dev->ifindex, handle,
209 dump_filter_nlmsg, &filter_info);
210 if (ret)
211 goto out;
212
213 out:
214 free(tcinfo.handle_array);
215 return 0;
216 }
217
query_flow_dissector(struct bpf_attach_info * attach_info)218 static int query_flow_dissector(struct bpf_attach_info *attach_info)
219 {
220 __u32 attach_flags;
221 __u32 prog_ids[1];
222 __u32 prog_cnt;
223 int err;
224 int fd;
225
226 fd = open("/proc/self/ns/net", O_RDONLY);
227 if (fd < 0) {
228 p_err("can't open /proc/self/ns/net: %s",
229 strerror(errno));
230 return -1;
231 }
232 prog_cnt = ARRAY_SIZE(prog_ids);
233 err = bpf_prog_query(fd, BPF_FLOW_DISSECTOR, 0,
234 &attach_flags, prog_ids, &prog_cnt);
235 close(fd);
236 if (err) {
237 if (errno == EINVAL) {
238 /* Older kernel's don't support querying
239 * flow dissector programs.
240 */
241 errno = 0;
242 return 0;
243 }
244 p_err("can't query prog: %s", strerror(errno));
245 return -1;
246 }
247
248 if (prog_cnt == 1)
249 attach_info->flow_dissector_id = prog_ids[0];
250
251 return 0;
252 }
253
net_parse_dev(int * argc,char *** argv)254 static int net_parse_dev(int *argc, char ***argv)
255 {
256 int ifindex;
257
258 if (is_prefix(**argv, "dev")) {
259 NEXT_ARGP();
260
261 ifindex = if_nametoindex(**argv);
262 if (!ifindex)
263 p_err("invalid devname %s", **argv);
264
265 NEXT_ARGP();
266 } else {
267 p_err("expected 'dev', got: '%s'?", **argv);
268 return -1;
269 }
270
271 return ifindex;
272 }
273
do_attach_detach_xdp(int progfd,enum net_attach_type attach_type,int ifindex,bool overwrite)274 static int do_attach_detach_xdp(int progfd, enum net_attach_type attach_type,
275 int ifindex, bool overwrite)
276 {
277 __u32 flags = 0;
278
279 if (!overwrite)
280 flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
281 if (attach_type == NET_ATTACH_TYPE_XDP_GENERIC)
282 flags |= XDP_FLAGS_SKB_MODE;
283 if (attach_type == NET_ATTACH_TYPE_XDP_DRIVER)
284 flags |= XDP_FLAGS_DRV_MODE;
285 if (attach_type == NET_ATTACH_TYPE_XDP_OFFLOAD)
286 flags |= XDP_FLAGS_HW_MODE;
287
288 return bpf_set_link_xdp_fd(ifindex, progfd, flags);
289 }
290
do_attach(int argc,char ** argv)291 static int do_attach(int argc, char **argv)
292 {
293 enum net_attach_type attach_type;
294 int progfd, ifindex, err = 0;
295 bool overwrite = false;
296
297 /* parse attach args */
298 if (!REQ_ARGS(5))
299 return -EINVAL;
300
301 attach_type = parse_attach_type(*argv);
302 if (attach_type == net_attach_type_size) {
303 p_err("invalid net attach/detach type: %s", *argv);
304 return -EINVAL;
305 }
306 NEXT_ARG();
307
308 progfd = prog_parse_fd(&argc, &argv);
309 if (progfd < 0)
310 return -EINVAL;
311
312 ifindex = net_parse_dev(&argc, &argv);
313 if (ifindex < 1) {
314 err = -EINVAL;
315 goto cleanup;
316 }
317
318 if (argc) {
319 if (is_prefix(*argv, "overwrite")) {
320 overwrite = true;
321 } else {
322 p_err("expected 'overwrite', got: '%s'?", *argv);
323 err = -EINVAL;
324 goto cleanup;
325 }
326 }
327
328 /* attach xdp prog */
329 if (is_prefix("xdp", attach_type_strings[attach_type]))
330 err = do_attach_detach_xdp(progfd, attach_type, ifindex,
331 overwrite);
332 if (err) {
333 p_err("interface %s attach failed: %s",
334 attach_type_strings[attach_type], strerror(-err));
335 goto cleanup;
336 }
337
338 if (json_output)
339 jsonw_null(json_wtr);
340 cleanup:
341 close(progfd);
342 return err;
343 }
344
do_detach(int argc,char ** argv)345 static int do_detach(int argc, char **argv)
346 {
347 enum net_attach_type attach_type;
348 int progfd, ifindex, err = 0;
349
350 /* parse detach args */
351 if (!REQ_ARGS(3))
352 return -EINVAL;
353
354 attach_type = parse_attach_type(*argv);
355 if (attach_type == net_attach_type_size) {
356 p_err("invalid net attach/detach type: %s", *argv);
357 return -EINVAL;
358 }
359 NEXT_ARG();
360
361 ifindex = net_parse_dev(&argc, &argv);
362 if (ifindex < 1)
363 return -EINVAL;
364
365 /* detach xdp prog */
366 progfd = -1;
367 if (is_prefix("xdp", attach_type_strings[attach_type]))
368 err = do_attach_detach_xdp(progfd, attach_type, ifindex, NULL);
369
370 if (err < 0) {
371 p_err("interface %s detach failed: %s",
372 attach_type_strings[attach_type], strerror(-err));
373 return err;
374 }
375
376 if (json_output)
377 jsonw_null(json_wtr);
378
379 return 0;
380 }
381
do_show(int argc,char ** argv)382 static int do_show(int argc, char **argv)
383 {
384 struct bpf_attach_info attach_info = {};
385 int i, sock, ret, filter_idx = -1;
386 struct bpf_netdev_t dev_array;
387 unsigned int nl_pid;
388 char err_buf[256];
389
390 if (argc == 2) {
391 filter_idx = net_parse_dev(&argc, &argv);
392 if (filter_idx < 1)
393 return -1;
394 } else if (argc != 0) {
395 usage();
396 }
397
398 ret = query_flow_dissector(&attach_info);
399 if (ret)
400 return -1;
401
402 sock = libbpf_netlink_open(&nl_pid);
403 if (sock < 0) {
404 fprintf(stderr, "failed to open netlink sock\n");
405 return -1;
406 }
407
408 dev_array.devices = NULL;
409 dev_array.used_len = 0;
410 dev_array.array_len = 0;
411 dev_array.filter_idx = filter_idx;
412
413 if (json_output)
414 jsonw_start_array(json_wtr);
415 NET_START_OBJECT;
416 NET_START_ARRAY("xdp", "%s:\n");
417 ret = libbpf_nl_get_link(sock, nl_pid, dump_link_nlmsg, &dev_array);
418 NET_END_ARRAY("\n");
419
420 if (!ret) {
421 NET_START_ARRAY("tc", "%s:\n");
422 for (i = 0; i < dev_array.used_len; i++) {
423 ret = show_dev_tc_bpf(sock, nl_pid,
424 &dev_array.devices[i]);
425 if (ret)
426 break;
427 }
428 NET_END_ARRAY("\n");
429 }
430
431 NET_START_ARRAY("flow_dissector", "%s:\n");
432 if (attach_info.flow_dissector_id > 0)
433 NET_DUMP_UINT("id", "id %u", attach_info.flow_dissector_id);
434 NET_END_ARRAY("\n");
435
436 NET_END_OBJECT;
437 if (json_output)
438 jsonw_end_array(json_wtr);
439
440 if (ret) {
441 if (json_output)
442 jsonw_null(json_wtr);
443 libbpf_strerror(ret, err_buf, sizeof(err_buf));
444 fprintf(stderr, "Error: %s\n", err_buf);
445 }
446 free(dev_array.devices);
447 close(sock);
448 return ret;
449 }
450
do_help(int argc,char ** argv)451 static int do_help(int argc, char **argv)
452 {
453 if (json_output) {
454 jsonw_null(json_wtr);
455 return 0;
456 }
457
458 fprintf(stderr,
459 "Usage: %s %s { show | list } [dev <devname>]\n"
460 " %s %s attach ATTACH_TYPE PROG dev <devname> [ overwrite ]\n"
461 " %s %s detach ATTACH_TYPE dev <devname>\n"
462 " %s %s help\n"
463 "\n"
464 " " HELP_SPEC_PROGRAM "\n"
465 " ATTACH_TYPE := { xdp | xdpgeneric | xdpdrv | xdpoffload }\n"
466 "\n"
467 "Note: Only xdp and tc attachments are supported now.\n"
468 " For progs attached to cgroups, use \"bpftool cgroup\"\n"
469 " to dump program attachments. For program types\n"
470 " sk_{filter,skb,msg,reuseport} and lwt/seg6, please\n"
471 " consult iproute2.\n",
472 bin_name, argv[-2], bin_name, argv[-2], bin_name, argv[-2],
473 bin_name, argv[-2]);
474
475 return 0;
476 }
477
478 static const struct cmd cmds[] = {
479 { "show", do_show },
480 { "list", do_show },
481 { "attach", do_attach },
482 { "detach", do_detach },
483 { "help", do_help },
484 { 0 }
485 };
486
do_net(int argc,char ** argv)487 int do_net(int argc, char **argv)
488 {
489 return cmd_select(cmds, argc, argv, do_help);
490 }
491