1
2
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
24int libbpf_netlink_open(__u32 *nl_pid)
25{
26 struct sockaddr_nl sa;
27 socklen_t addrlen;
28 int one = 1, ret;
29 int sock;
30
31 memset(&sa, 0, sizeof(sa));
32 sa.nl_family = AF_NETLINK;
33
34 sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
35 if (sock < 0)
36 return -errno;
37
38 if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK,
39 &one, sizeof(one)) < 0) {
40 fprintf(stderr, "Netlink error reporting not supported\n");
41 }
42
43 if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
44 ret = -errno;
45 goto cleanup;
46 }
47
48 addrlen = sizeof(sa);
49 if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) {
50 ret = -errno;
51 goto cleanup;
52 }
53
54 if (addrlen != sizeof(sa)) {
55 ret = -LIBBPF_ERRNO__INTERNAL;
56 goto cleanup;
57 }
58
59 *nl_pid = sa.nl_pid;
60 return sock;
61
62cleanup:
63 close(sock);
64 return ret;
65}
66
67static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq,
68 __dump_nlmsg_t _fn, libbpf_dump_nlmsg_t fn,
69 void *cookie)
70{
71 bool multipart = true;
72 struct nlmsgerr *err;
73 struct nlmsghdr *nh;
74 char buf[4096];
75 int len, ret;
76
77 while (multipart) {
78 multipart = false;
79 len = recv(sock, buf, sizeof(buf), 0);
80 if (len < 0) {
81 ret = -errno;
82 goto done;
83 }
84
85 if (len == 0)
86 break;
87
88 for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
89 nh = NLMSG_NEXT(nh, len)) {
90 if (nh->nlmsg_pid != nl_pid) {
91 ret = -LIBBPF_ERRNO__WRNGPID;
92 goto done;
93 }
94 if (nh->nlmsg_seq != seq) {
95 ret = -LIBBPF_ERRNO__INVSEQ;
96 goto done;
97 }
98 if (nh->nlmsg_flags & NLM_F_MULTI)
99 multipart = true;
100 switch (nh->nlmsg_type) {
101 case NLMSG_ERROR:
102 err = (struct nlmsgerr *)NLMSG_DATA(nh);
103 if (!err->error)
104 continue;
105 ret = err->error;
106 libbpf_nla_dump_errormsg(nh);
107 goto done;
108 case NLMSG_DONE:
109 return 0;
110 default:
111 break;
112 }
113 if (_fn) {
114 ret = _fn(nh, fn, cookie);
115 if (ret)
116 return ret;
117 }
118 }
119 }
120 ret = 0;
121done:
122 return ret;
123}
124
125int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags)
126{
127 int sock, seq = 0, ret;
128 struct nlattr *nla, *nla_xdp;
129 struct {
130 struct nlmsghdr nh;
131 struct ifinfomsg ifinfo;
132 char attrbuf[64];
133 } req;
134 __u32 nl_pid;
135
136 sock = libbpf_netlink_open(&nl_pid);
137 if (sock < 0)
138 return sock;
139
140 memset(&req, 0, sizeof(req));
141 req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
142 req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
143 req.nh.nlmsg_type = RTM_SETLINK;
144 req.nh.nlmsg_pid = 0;
145 req.nh.nlmsg_seq = ++seq;
146 req.ifinfo.ifi_family = AF_UNSPEC;
147 req.ifinfo.ifi_index = ifindex;
148
149
150 nla = (struct nlattr *)(((char *)&req)
151 + NLMSG_ALIGN(req.nh.nlmsg_len));
152 nla->nla_type = NLA_F_NESTED | IFLA_XDP;
153 nla->nla_len = NLA_HDRLEN;
154
155
156 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
157 nla_xdp->nla_type = IFLA_XDP_FD;
158 nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
159 memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
160 nla->nla_len += nla_xdp->nla_len;
161
162
163 if (flags) {
164 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len);
165 nla_xdp->nla_type = IFLA_XDP_FLAGS;
166 nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags);
167 memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags));
168 nla->nla_len += nla_xdp->nla_len;
169 }
170
171 req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
172
173 if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
174 ret = -errno;
175 goto cleanup;
176 }
177 ret = bpf_netlink_recv(sock, nl_pid, seq, NULL, NULL, NULL);
178
179cleanup:
180 close(sock);
181 return ret;
182}
183
184static int __dump_link_nlmsg(struct nlmsghdr *nlh,
185 libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
186{
187 struct nlattr *tb[IFLA_MAX + 1], *attr;
188 struct ifinfomsg *ifi = NLMSG_DATA(nlh);
189 int len;
190
191 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
192 attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi)));
193 if (libbpf_nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0)
194 return -LIBBPF_ERRNO__NLPARSE;
195
196 return dump_link_nlmsg(cookie, ifi, tb);
197}
198
199int libbpf_nl_get_link(int sock, unsigned int nl_pid,
200 libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie)
201{
202 struct {
203 struct nlmsghdr nlh;
204 struct ifinfomsg ifm;
205 } req = {
206 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
207 .nlh.nlmsg_type = RTM_GETLINK,
208 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
209 .ifm.ifi_family = AF_PACKET,
210 };
211 int seq = time(NULL);
212
213 req.nlh.nlmsg_seq = seq;
214 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
215 return -errno;
216
217 return bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg,
218 dump_link_nlmsg, cookie);
219}
220
221static int __dump_class_nlmsg(struct nlmsghdr *nlh,
222 libbpf_dump_nlmsg_t dump_class_nlmsg,
223 void *cookie)
224{
225 struct nlattr *tb[TCA_MAX + 1], *attr;
226 struct tcmsg *t = NLMSG_DATA(nlh);
227 int len;
228
229 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
230 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
231 if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
232 return -LIBBPF_ERRNO__NLPARSE;
233
234 return dump_class_nlmsg(cookie, t, tb);
235}
236
237int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex,
238 libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie)
239{
240 struct {
241 struct nlmsghdr nlh;
242 struct tcmsg t;
243 } req = {
244 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
245 .nlh.nlmsg_type = RTM_GETTCLASS,
246 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
247 .t.tcm_family = AF_UNSPEC,
248 .t.tcm_ifindex = ifindex,
249 };
250 int seq = time(NULL);
251
252 req.nlh.nlmsg_seq = seq;
253 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
254 return -errno;
255
256 return bpf_netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg,
257 dump_class_nlmsg, cookie);
258}
259
260static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh,
261 libbpf_dump_nlmsg_t dump_qdisc_nlmsg,
262 void *cookie)
263{
264 struct nlattr *tb[TCA_MAX + 1], *attr;
265 struct tcmsg *t = NLMSG_DATA(nlh);
266 int len;
267
268 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
269 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
270 if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
271 return -LIBBPF_ERRNO__NLPARSE;
272
273 return dump_qdisc_nlmsg(cookie, t, tb);
274}
275
276int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex,
277 libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie)
278{
279 struct {
280 struct nlmsghdr nlh;
281 struct tcmsg t;
282 } req = {
283 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
284 .nlh.nlmsg_type = RTM_GETQDISC,
285 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
286 .t.tcm_family = AF_UNSPEC,
287 .t.tcm_ifindex = ifindex,
288 };
289 int seq = time(NULL);
290
291 req.nlh.nlmsg_seq = seq;
292 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
293 return -errno;
294
295 return bpf_netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg,
296 dump_qdisc_nlmsg, cookie);
297}
298
299static int __dump_filter_nlmsg(struct nlmsghdr *nlh,
300 libbpf_dump_nlmsg_t dump_filter_nlmsg,
301 void *cookie)
302{
303 struct nlattr *tb[TCA_MAX + 1], *attr;
304 struct tcmsg *t = NLMSG_DATA(nlh);
305 int len;
306
307 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t));
308 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t)));
309 if (libbpf_nla_parse(tb, TCA_MAX, attr, len, NULL) != 0)
310 return -LIBBPF_ERRNO__NLPARSE;
311
312 return dump_filter_nlmsg(cookie, t, tb);
313}
314
315int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle,
316 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie)
317{
318 struct {
319 struct nlmsghdr nlh;
320 struct tcmsg t;
321 } req = {
322 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)),
323 .nlh.nlmsg_type = RTM_GETTFILTER,
324 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
325 .t.tcm_family = AF_UNSPEC,
326 .t.tcm_ifindex = ifindex,
327 .t.tcm_parent = handle,
328 };
329 int seq = time(NULL);
330
331 req.nlh.nlmsg_seq = seq;
332 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0)
333 return -errno;
334
335 return bpf_netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg,
336 dump_filter_nlmsg, cookie);
337}
338
