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