1 // SPDX-License-Identifier: LGPL-2.1 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 21 int bpf_netlink_open(__u32 *nl_pid) 22 { 23 struct sockaddr_nl sa; 24 socklen_t addrlen; 25 int one = 1, ret; 26 int sock; 27 28 memset(&sa, 0, sizeof(sa)); 29 sa.nl_family = AF_NETLINK; 30 31 sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); 32 if (sock < 0) 33 return -errno; 34 35 if (setsockopt(sock, SOL_NETLINK, NETLINK_EXT_ACK, 36 &one, sizeof(one)) < 0) { 37 fprintf(stderr, "Netlink error reporting not supported\n"); 38 } 39 40 if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) { 41 ret = -errno; 42 goto cleanup; 43 } 44 45 addrlen = sizeof(sa); 46 if (getsockname(sock, (struct sockaddr *)&sa, &addrlen) < 0) { 47 ret = -errno; 48 goto cleanup; 49 } 50 51 if (addrlen != sizeof(sa)) { 52 ret = -LIBBPF_ERRNO__INTERNAL; 53 goto cleanup; 54 } 55 56 *nl_pid = sa.nl_pid; 57 return sock; 58 59 cleanup: 60 close(sock); 61 return ret; 62 } 63 64 static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq, 65 __dump_nlmsg_t _fn, dump_nlmsg_t fn, 66 void *cookie) 67 { 68 struct nlmsgerr *err; 69 struct nlmsghdr *nh; 70 char buf[4096]; 71 int len, ret; 72 73 while (1) { 74 len = recv(sock, buf, sizeof(buf), 0); 75 if (len < 0) { 76 ret = -errno; 77 goto done; 78 } 79 80 for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len); 81 nh = NLMSG_NEXT(nh, len)) { 82 if (nh->nlmsg_pid != nl_pid) { 83 ret = -LIBBPF_ERRNO__WRNGPID; 84 goto done; 85 } 86 if (nh->nlmsg_seq != seq) { 87 ret = -LIBBPF_ERRNO__INVSEQ; 88 goto done; 89 } 90 switch (nh->nlmsg_type) { 91 case NLMSG_ERROR: 92 err = (struct nlmsgerr *)NLMSG_DATA(nh); 93 if (!err->error) 94 continue; 95 ret = err->error; 96 nla_dump_errormsg(nh); 97 goto done; 98 case NLMSG_DONE: 99 return 0; 100 default: 101 break; 102 } 103 if (_fn) { 104 ret = _fn(nh, fn, cookie); 105 if (ret) 106 return ret; 107 } 108 } 109 } 110 ret = 0; 111 done: 112 return ret; 113 } 114 115 int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) 116 { 117 int sock, seq = 0, ret; 118 struct nlattr *nla, *nla_xdp; 119 struct { 120 struct nlmsghdr nh; 121 struct ifinfomsg ifinfo; 122 char attrbuf[64]; 123 } req; 124 __u32 nl_pid; 125 126 sock = bpf_netlink_open(&nl_pid); 127 if (sock < 0) 128 return sock; 129 130 memset(&req, 0, sizeof(req)); 131 req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)); 132 req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; 133 req.nh.nlmsg_type = RTM_SETLINK; 134 req.nh.nlmsg_pid = 0; 135 req.nh.nlmsg_seq = ++seq; 136 req.ifinfo.ifi_family = AF_UNSPEC; 137 req.ifinfo.ifi_index = ifindex; 138 139 /* started nested attribute for XDP */ 140 nla = (struct nlattr *)(((char *)&req) 141 + NLMSG_ALIGN(req.nh.nlmsg_len)); 142 nla->nla_type = NLA_F_NESTED | IFLA_XDP; 143 nla->nla_len = NLA_HDRLEN; 144 145 /* add XDP fd */ 146 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); 147 nla_xdp->nla_type = IFLA_XDP_FD; 148 nla_xdp->nla_len = NLA_HDRLEN + sizeof(int); 149 memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd)); 150 nla->nla_len += nla_xdp->nla_len; 151 152 /* if user passed in any flags, add those too */ 153 if (flags) { 154 nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); 155 nla_xdp->nla_type = IFLA_XDP_FLAGS; 156 nla_xdp->nla_len = NLA_HDRLEN + sizeof(flags); 157 memcpy((char *)nla_xdp + NLA_HDRLEN, &flags, sizeof(flags)); 158 nla->nla_len += nla_xdp->nla_len; 159 } 160 161 req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len); 162 163 if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) { 164 ret = -errno; 165 goto cleanup; 166 } 167 ret = bpf_netlink_recv(sock, nl_pid, seq, NULL, NULL, NULL); 168 169 cleanup: 170 close(sock); 171 return ret; 172 } 173 174 static int __dump_link_nlmsg(struct nlmsghdr *nlh, dump_nlmsg_t dump_link_nlmsg, 175 void *cookie) 176 { 177 struct nlattr *tb[IFLA_MAX + 1], *attr; 178 struct ifinfomsg *ifi = NLMSG_DATA(nlh); 179 int len; 180 181 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi)); 182 attr = (struct nlattr *) ((void *) ifi + NLMSG_ALIGN(sizeof(*ifi))); 183 if (nla_parse(tb, IFLA_MAX, attr, len, NULL) != 0) 184 return -LIBBPF_ERRNO__NLPARSE; 185 186 return dump_link_nlmsg(cookie, ifi, tb); 187 } 188 189 int nl_get_link(int sock, unsigned int nl_pid, dump_nlmsg_t dump_link_nlmsg, 190 void *cookie) 191 { 192 struct { 193 struct nlmsghdr nlh; 194 struct ifinfomsg ifm; 195 } req = { 196 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)), 197 .nlh.nlmsg_type = RTM_GETLINK, 198 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, 199 .ifm.ifi_family = AF_PACKET, 200 }; 201 int seq = time(NULL); 202 203 req.nlh.nlmsg_seq = seq; 204 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) 205 return -errno; 206 207 return bpf_netlink_recv(sock, nl_pid, seq, __dump_link_nlmsg, 208 dump_link_nlmsg, cookie); 209 } 210 211 static int __dump_class_nlmsg(struct nlmsghdr *nlh, 212 dump_nlmsg_t dump_class_nlmsg, void *cookie) 213 { 214 struct nlattr *tb[TCA_MAX + 1], *attr; 215 struct tcmsg *t = NLMSG_DATA(nlh); 216 int len; 217 218 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t)); 219 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t))); 220 if (nla_parse(tb, TCA_MAX, attr, len, NULL) != 0) 221 return -LIBBPF_ERRNO__NLPARSE; 222 223 return dump_class_nlmsg(cookie, t, tb); 224 } 225 226 int nl_get_class(int sock, unsigned int nl_pid, int ifindex, 227 dump_nlmsg_t dump_class_nlmsg, void *cookie) 228 { 229 struct { 230 struct nlmsghdr nlh; 231 struct tcmsg t; 232 } req = { 233 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)), 234 .nlh.nlmsg_type = RTM_GETTCLASS, 235 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, 236 .t.tcm_family = AF_UNSPEC, 237 .t.tcm_ifindex = ifindex, 238 }; 239 int seq = time(NULL); 240 241 req.nlh.nlmsg_seq = seq; 242 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) 243 return -errno; 244 245 return bpf_netlink_recv(sock, nl_pid, seq, __dump_class_nlmsg, 246 dump_class_nlmsg, cookie); 247 } 248 249 static int __dump_qdisc_nlmsg(struct nlmsghdr *nlh, 250 dump_nlmsg_t dump_qdisc_nlmsg, void *cookie) 251 { 252 struct nlattr *tb[TCA_MAX + 1], *attr; 253 struct tcmsg *t = NLMSG_DATA(nlh); 254 int len; 255 256 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t)); 257 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t))); 258 if (nla_parse(tb, TCA_MAX, attr, len, NULL) != 0) 259 return -LIBBPF_ERRNO__NLPARSE; 260 261 return dump_qdisc_nlmsg(cookie, t, tb); 262 } 263 264 int nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex, 265 dump_nlmsg_t dump_qdisc_nlmsg, void *cookie) 266 { 267 struct { 268 struct nlmsghdr nlh; 269 struct tcmsg t; 270 } req = { 271 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)), 272 .nlh.nlmsg_type = RTM_GETQDISC, 273 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, 274 .t.tcm_family = AF_UNSPEC, 275 .t.tcm_ifindex = ifindex, 276 }; 277 int seq = time(NULL); 278 279 req.nlh.nlmsg_seq = seq; 280 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) 281 return -errno; 282 283 return bpf_netlink_recv(sock, nl_pid, seq, __dump_qdisc_nlmsg, 284 dump_qdisc_nlmsg, cookie); 285 } 286 287 static int __dump_filter_nlmsg(struct nlmsghdr *nlh, 288 dump_nlmsg_t dump_filter_nlmsg, void *cookie) 289 { 290 struct nlattr *tb[TCA_MAX + 1], *attr; 291 struct tcmsg *t = NLMSG_DATA(nlh); 292 int len; 293 294 len = nlh->nlmsg_len - NLMSG_LENGTH(sizeof(*t)); 295 attr = (struct nlattr *) ((void *) t + NLMSG_ALIGN(sizeof(*t))); 296 if (nla_parse(tb, TCA_MAX, attr, len, NULL) != 0) 297 return -LIBBPF_ERRNO__NLPARSE; 298 299 return dump_filter_nlmsg(cookie, t, tb); 300 } 301 302 int nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle, 303 dump_nlmsg_t dump_filter_nlmsg, void *cookie) 304 { 305 struct { 306 struct nlmsghdr nlh; 307 struct tcmsg t; 308 } req = { 309 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct tcmsg)), 310 .nlh.nlmsg_type = RTM_GETTFILTER, 311 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST, 312 .t.tcm_family = AF_UNSPEC, 313 .t.tcm_ifindex = ifindex, 314 .t.tcm_parent = handle, 315 }; 316 int seq = time(NULL); 317 318 req.nlh.nlmsg_seq = seq; 319 if (send(sock, &req, req.nlh.nlmsg_len, 0) < 0) 320 return -errno; 321 322 return bpf_netlink_recv(sock, nl_pid, seq, __dump_filter_nlmsg, 323 dump_filter_nlmsg, cookie); 324 } 325