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1// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2/* Copyright (c) 2018 Facebook */
3
4#include <stdlib.h>
5#include <memory.h>
6#include <unistd.h>
7#include <linux/bpf.h>
8#include <linux/rtnetlink.h>
9#include <sys/socket.h>
10#include <errno.h>
11#include <time.h>
12
13#include "bpf.h"
14#include "libbpf.h"
15#include "libbpf_internal.h"
16#include "nlattr.h"
17
18/* make sure libbpf doesn't use kernel-only integer typedefs */
19#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
20
21#ifndef SOL_NETLINK
22#define SOL_NETLINK 270
23#endif
24
25typedef int (*__dump_nlmsg_t)(struct nlmsghdr *nlmsg, libbpf_dump_nlmsg_t,
26 void *cookie);
27
28struct xdp_id_md {
29 int ifindex;
30 __u32 flags;
31 struct xdp_link_info info;
32};
33
34int libbpf_netlink_open(__u32 *nl_pid)
35{
36 struct sockaddr_nl sa;
37 socklen_t addrlen;
38 int one = 1, ret;
39 int sock;
40
41 memset(&sa, 0, sizeof(sa));
42 sa.nl_family = AF_NETLINK;
43
44 sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
45 if (sock < 0)
46 return -errno;
47
48 if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
49 &one, sizeof(one)) < 0) {
50 pr_warn("Netlink error reporting not supported\n");
51 }
52
53 if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
54 ret = -errno;
55 goto cleanup;
56 }
57
58 addrlen = sizeof(sa);
59 if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
60 ret = -errno;
61 goto cleanup;
62 }
63
64 if (addrlen != sizeof(sa)) {
65 ret = -LIBBPF_ERRNO__INTERNAL;
66 goto cleanup;
67 }
68
69 *nl_pid = sa.nl_pid;
70 return sock;
71
72cleanup:
73 close(sock);
74 return ret;
75}
76
77static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq,
78 __dump_nlmsg_t _fn, libbpf_dump_nlmsg_t fn,
79 void *cookie)
80{
81 bool multipart = true;
82 struct nlmsgerr *err;
83 struct nlmsghdr *nh;
84 char buf[4096];
85 int len, ret;
86
87 while (multipart) {
88 multipart = false;
89 len = recv(sock, buf, sizeof(buf), 0);
90 if (len < 0) {
91 ret = -errno;
92 goto done;
93 }
94
95 if (len == 0)
96 break;
97
98 for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
99 nh = NLMSG_NEXT(nh, len)) {
100 if (nh->nlmsg_pid != nl_pid) {
101 ret = -LIBBPF_ERRNO__WRNGPID;
102 goto done;
103 }
104 if (nh->nlmsg_seq != seq) {
105 ret = -LIBBPF_ERRNO__INVSEQ;
106 goto done;
107 }
108 if (nh->nlmsg_flags & NLM_F_MULTI)
109 multipart = true;
110 switch (nh->nlmsg_type) {
111 case NLMSG_ERROR:
112 err = (struct nlmsgerr *)NLMSG_DATA(nh);
113 if (!err->error)
114 continue;
115 ret = err->error;
116 libbpf_nla_dump_errormsg(nh);
117 goto done;
118 case NLMSG_DONE:
119 return 0;
120 default:
121 break;
122 }
123 if (_fn) {
124 ret = _fn(nh, fn, cookie);
125 if (ret)
126 return ret;
127 }
128 }
129 }
130 ret = 0;
131done:
132 return ret;
133}
134
135static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd,
136 __u32 flags)
137{
138 int sock, seq = 0, ret;
139 struct nlattr *nla, *nla_xdp;
140 struct {
141 struct nlmsghdr nh;
142 struct ifinfomsg ifinfo;
143 char attrbuf[64];
144 } req;
145 __u32 nl_pid = 0;
146
147 sock = libbpf_netlink_open(&nl_pid);
148 if (sock < 0)
149 return sock;
150
151 memset(&req, 0, sizeof(req));
152 req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
153 req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
154 req.nh.nlmsg_type = RTM_SETLINK;
155 req.nh.nlmsg_pid = 0;
156 req.nh.nlmsg_seq = ++seq;
157 req.ifinfo.ifi_family = AF_UNSPEC;
158 req.ifinfo.ifi_index = ifindex;
159
160 /* started nested attribute for XDP */
161 nla = (struct nlattr *)(((char *)&req)
162 + NLMSG_ALIGN(req.nh.nlmsg_len));
163 nla->nla_type = NLA_F_NESTED | IFLA_XDP;
164 nla->nla_len = NLA_HDRLEN;
165
166 /* add XDP fd */
167 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
168 nla_xdp->nla_type = IFLA_XDP_FD;
169 nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
170 memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
171 nla->nla_len += nla_xdp->nla_len;
172
173 /* if user passed in any flags, add those too */
174 if (flags) {
175 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
176 nla_xdp->nla_type = IFLA_XDP_FLAGS;
177 nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags);
178 memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags));
179 nla->nla_len += nla_xdp->nla_len;
180 }
181
182 if (flags & XDP_FLAGS_REPLACE) {
183 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
184 nla_xdp->nla_type = IFLA_XDP_EXPECTED_FD;
185 nla_xdp->nla_len = NLA_HDRLEN + sizeof(old_fd);
186 memcpy((char *)nla_xdp + NLA_HDRLEN, &old_fd, sizeof(old_fd));
187 nla->nla_len += nla_xdp->nla_len;
188 }
189
190 req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
191
192 if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
193 ret = -errno;
194 goto cleanup;
195 }
196 ret = bpf_netlink_recv(sock, nl_pid, seq, NULL, NULL, NULL);
197
198cleanup:
199 close(sock);
200 return ret;
201}
202
203int bpf_set_link_xdp_fd_opts(int ifindex, int fd, __u32 flags,
204 const struct bpf_xdp_set_link_opts *opts)
205{
206 int old_fd = -1;
207
208 if (!OPTS_VALID(opts, bpf_xdp_set_link_opts))
209 return -EINVAL;
210
211 if (OPTS_HAS(opts, old_fd)) {
212 old_fd = OPTS_GET(opts, old_fd, -1);
213 flags |= XDP_FLAGS_REPLACE;
214 }
215
216 return __bpf_set_link_xdp_fd_replace(ifindex, fd,
217 old_fd,
218 flags);
219}
220
221int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
222{
223 return __bpf_set_link_xdp_fd_replace(ifindex, fd, 0, flags);
224}
225
226static int __dump_link_nlmsg(struct nlmsghdr *nlh,
227 libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
228{
229 struct nlattr *tb[IFLA_MAX + 1], *attr;
230 struct ifinfomsg *ifi = NLMSG_DATA(nlh);
231 int len;
232
233 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
234 attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
235 if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
236 return -LIBBPF_ERRNO__NLPARSE;
237
238 return dump_link_nlmsg(cookie, ifi, tb);
239}
240
241static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb)
242{
243 struct nlattr *xdp_tb[IFLA_XDP_MAX + 1];
244 struct xdp_id_md *xdp_id = cookie;
245 struct ifinfomsg *ifinfo = msg;
246 int ret;
247
248 if (xdp_id->ifindex && xdp_id->ifindex != ifinfo->ifi_index)
249 return 0;
250
251 if (!tb[IFLA_XDP])
252 return 0;
253
254 ret = libbpf_nla_parse_nested(xdp_tb, IFLA_XDP_MAX, tb[IFLA_XDP], NULL);
255 if (ret)
256 return ret;
257
258 if (!xdp_tb[IFLA_XDP_ATTACHED])
259 return 0;
260
261 xdp_id->info.attach_mode = libbpf_nla_getattr_u8(
262 xdp_tb[IFLA_XDP_ATTACHED]);
263
264 if (xdp_id->info.attach_mode == XDP_ATTACHED_NONE)
265 return 0;
266
267 if (xdp_tb[IFLA_XDP_PROG_ID])
268 xdp_id->info.prog_id = libbpf_nla_getattr_u32(
269 xdp_tb[IFLA_XDP_PROG_ID]);
270
271 if (xdp_tb[IFLA_XDP_SKB_PROG_ID])
272 xdp_id->info.skb_prog_id = libbpf_nla_getattr_u32(
273 xdp_tb[IFLA_XDP_SKB_PROG_ID]);
274
275 if (xdp_tb[IFLA_XDP_DRV_PROG_ID])
276 xdp_id->info.drv_prog_id = libbpf_nla_getattr_u32(
277 xdp_tb[IFLA_XDP_DRV_PROG_ID]);
278
279 if (xdp_tb[IFLA_XDP_HW_PROG_ID])
280 xdp_id->info.hw_prog_id = libbpf_nla_getattr_u32(
281 xdp_tb[IFLA_XDP_HW_PROG_ID]);
282
283 return 0;
284}
285
286int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
287 size_t info_size, __u32 flags)
288{
289 struct xdp_id_md xdp_id = {};
290 int sock, ret;
291 __u32 nl_pid = 0;
292 __u32 mask;
293
294 if (flags & ~XDP_FLAGS_MASK || !info_size)
295 return -EINVAL;
296
297 /* Check whether the single {HW,DRV,SKB} mode is set */
298 flags &= (XDP_FLAGS_SKB_MODE | XDP_FLAGS_DRV_MODE | XDP_FLAGS_HW_MODE);
299 mask = flags - 1;
300 if (flags && flags & mask)
301 return -EINVAL;
302
303 sock = libbpf_netlink_open(&nl_pid);
304 if (sock < 0)
305 return sock;
306
307 xdp_id.ifindex = ifindex;
308 xdp_id.flags = flags;
309
310 ret = libbpf_nl_get_link(sock, nl_pid, get_xdp_info, &xdp_id);
311 if (!ret) {
312 size_t sz = min(info_size, sizeof(xdp_id.info));
313
314 memcpy(info, &xdp_id.info, sz);
315 memset((void *) info + sz, 0, info_size - sz);
316 }
317
318 close(sock);
319 return ret;
320}
321
322static __u32 get_xdp_id(struct xdp_link_info *info, __u32 flags)
323{
324 flags &= XDP_FLAGS_MODES;
325
326 if (info->attach_mode != XDP_ATTACHED_MULTI && !flags)
327 return info->prog_id;
328 if (flags & XDP_FLAGS_DRV_MODE)
329 return info->drv_prog_id;
330 if (flags & XDP_FLAGS_HW_MODE)
331 return info->hw_prog_id;
332 if (flags & XDP_FLAGS_SKB_MODE)
333 return info->skb_prog_id;
334
335 return 0;
336}
337
338int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags)
339{
340 struct xdp_link_info info;
341 int ret;
342
343 ret = bpf_get_link_xdp_info(ifindex, &info, sizeof(info), flags);
344 if (!ret)
345 *prog_id = get_xdp_id(&info, flags);
346
347 return ret;
348}
349
350int libbpf_nl_get_link(int sock, unsigned int nl_pid,
351 libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
352{
353 struct {
354 struct nlmsghdr nlh;
355 struct ifinfomsg ifm;
356 } req = {
357 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
358 .nlh.nlmsg_type = RTM_GETLINK,
359 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
360 .ifm.ifi_family = AF_PACKET,
361 };
362 int seq = time(NULL);
363
364 req.nlh.nlmsg_seq = seq;
365 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
366 return -errno;
367
368 return bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
369 dump_link_nlmsg, cookie);
370}
371
372static int __dump_class_nlmsg(struct nlmsghdr *nlh,
373 libbpf_dump_nlmsg_t dump_class_nlmsg,
374 void *cookie)
375{
376 struct nlattr *tb[TCA_MAX + 1], *attr;
377 struct tcmsg *t = NLMSG_DATA(nlh);
378 int len;
379
380 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
381 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
382 if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
383 return -LIBBPF_ERRNO__NLPARSE;
384
385 return dump_class_nlmsg(cookie, t, tb);
386}
387
388int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
389 libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie)
390{
391 struct {
392 struct nlmsghdr nlh;
393 struct tcmsg t;
394 } req = {
395 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
396 .nlh.nlmsg_type = RTM_GETTCLASS,
397 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
398 .t.tcm_family = AF_UNSPEC,
399 .t.tcm_ifindex = ifindex,
400 };
401 int seq = time(NULL);
402
403 req.nlh.nlmsg_seq = seq;
404 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
405 return -errno;
406
407 return bpf_netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
408 dump_class_nlmsg, cookie);
409}
410
411static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
412 libbpf_dump_nlmsg_t dump_qdisc_nlmsg,
413 void *cookie)
414{
415 struct nlattr *tb[TCA_MAX + 1], *attr;
416 struct tcmsg *t = NLMSG_DATA(nlh);
417 int len;
418
419 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
420 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
421 if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
422 return -LIBBPF_ERRNO__NLPARSE;
423
424 return dump_qdisc_nlmsg(cookie, t, tb);
425}
426
427int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
428 libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
429{
430 struct {
431 struct nlmsghdr nlh;
432 struct tcmsg t;
433 } req = {
434 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
435 .nlh.nlmsg_type = RTM_GETQDISC,
436 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
437 .t.tcm_family = AF_UNSPEC,
438 .t.tcm_ifindex = ifindex,
439 };
440 int seq = time(NULL);
441
442 req.nlh.nlmsg_seq = seq;
443 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
444 return -errno;
445
446 return bpf_netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
447 dump_qdisc_nlmsg, cookie);
448}
449
450static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
451 libbpf_dump_nlmsg_t dump_filter_nlmsg,
452 void *cookie)
453{
454 struct nlattr *tb[TCA_MAX + 1], *attr;
455 struct tcmsg *t = NLMSG_DATA(nlh);
456 int len;
457
458 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
459 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
460 if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
461 return -LIBBPF_ERRNO__NLPARSE;
462
463 return dump_filter_nlmsg(cookie, t, tb);
464}
465
466int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
467 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie)
468{
469 struct {
470 struct nlmsghdr nlh;
471 struct tcmsg t;
472 } req = {
473 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
474 .nlh.nlmsg_type = RTM_GETTFILTER,
475 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
476 .t.tcm_family = AF_UNSPEC,
477 .t.tcm_ifindex = ifindex,
478 .t.tcm_parent = handle,
479 };
480 int seq = time(NULL);
481
482 req.nlh.nlmsg_seq = seq;
483 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
484 return -errno;
485
486 return bpf_netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
487 dump_filter_nlmsg, cookie);
488}