1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * net/psample/psample.c - Netlink channel for packet sampling 4 * Copyright (c) 2017 Yotam Gigi <yotamg@mellanox.com> 5 */ 6 7 #include <linux/types.h> 8 #include <linux/kernel.h> 9 #include <linux/skbuff.h> 10 #include <linux/module.h> 11 #include <linux/timekeeping.h> 12 #include <net/net_namespace.h> 13 #include <net/sock.h> 14 #include <net/netlink.h> 15 #include <net/genetlink.h> 16 #include <net/psample.h> 17 #include <linux/spinlock.h> 18 #include <net/ip_tunnels.h> 19 #include <net/dst_metadata.h> 20 21 #define PSAMPLE_MAX_PACKET_SIZE 0xffff 22 23 static LIST_HEAD(psample_groups_list); 24 static DEFINE_SPINLOCK(psample_groups_lock); 25 26 /* multicast groups */ 27 enum psample_nl_multicast_groups { 28 PSAMPLE_NL_MCGRP_CONFIG, 29 PSAMPLE_NL_MCGRP_SAMPLE, 30 }; 31 32 static const struct genl_multicast_group psample_nl_mcgrps[] = { 33 [PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME }, 34 [PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME, 35 .flags = GENL_MCAST_CAP_NET_ADMIN, }, 36 }; 37 38 static struct genl_family psample_nl_family __ro_after_init; 39 40 static int psample_group_nl_fill(struct sk_buff *msg, 41 struct psample_group *group, 42 enum psample_command cmd, u32 portid, u32 seq, 43 int flags) 44 { 45 void *hdr; 46 int ret; 47 48 hdr = genlmsg_put(msg, portid, seq, &psample_nl_family, flags, cmd); 49 if (!hdr) 50 return -EMSGSIZE; 51 52 ret = nla_put_u32(msg, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num); 53 if (ret < 0) 54 goto error; 55 56 ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_REFCOUNT, group->refcount); 57 if (ret < 0) 58 goto error; 59 60 ret = nla_put_u32(msg, PSAMPLE_ATTR_GROUP_SEQ, group->seq); 61 if (ret < 0) 62 goto error; 63 64 genlmsg_end(msg, hdr); 65 return 0; 66 67 error: 68 genlmsg_cancel(msg, hdr); 69 return -EMSGSIZE; 70 } 71 72 static int psample_nl_cmd_get_group_dumpit(struct sk_buff *msg, 73 struct netlink_callback *cb) 74 { 75 struct psample_group *group; 76 int start = cb->args[0]; 77 int idx = 0; 78 int err; 79 80 spin_lock_bh(&psample_groups_lock); 81 list_for_each_entry(group, &psample_groups_list, list) { 82 if (!net_eq(group->net, sock_net(msg->sk))) 83 continue; 84 if (idx < start) { 85 idx++; 86 continue; 87 } 88 err = psample_group_nl_fill(msg, group, PSAMPLE_CMD_NEW_GROUP, 89 NETLINK_CB(cb->skb).portid, 90 cb->nlh->nlmsg_seq, NLM_F_MULTI); 91 if (err) 92 break; 93 idx++; 94 } 95 96 spin_unlock_bh(&psample_groups_lock); 97 cb->args[0] = idx; 98 return msg->len; 99 } 100 101 static const struct genl_small_ops psample_nl_ops[] = { 102 { 103 .cmd = PSAMPLE_CMD_GET_GROUP, 104 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 105 .dumpit = psample_nl_cmd_get_group_dumpit, 106 /* can be retrieved by unprivileged users */ 107 } 108 }; 109 110 static struct genl_family psample_nl_family __ro_after_init = { 111 .name = PSAMPLE_GENL_NAME, 112 .version = PSAMPLE_GENL_VERSION, 113 .maxattr = PSAMPLE_ATTR_MAX, 114 .netnsok = true, 115 .module = THIS_MODULE, 116 .mcgrps = psample_nl_mcgrps, 117 .small_ops = psample_nl_ops, 118 .n_small_ops = ARRAY_SIZE(psample_nl_ops), 119 .resv_start_op = PSAMPLE_CMD_GET_GROUP + 1, 120 .n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps), 121 }; 122 123 static void psample_group_notify(struct psample_group *group, 124 enum psample_command cmd) 125 { 126 struct sk_buff *msg; 127 int err; 128 129 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); 130 if (!msg) 131 return; 132 133 err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI); 134 if (!err) 135 genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0, 136 PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC); 137 else 138 nlmsg_free(msg); 139 } 140 141 static struct psample_group *psample_group_create(struct net *net, 142 u32 group_num) 143 { 144 struct psample_group *group; 145 146 group = kzalloc(sizeof(*group), GFP_ATOMIC); 147 if (!group) 148 return NULL; 149 150 group->net = net; 151 group->group_num = group_num; 152 list_add_tail(&group->list, &psample_groups_list); 153 154 psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP); 155 return group; 156 } 157 158 static void psample_group_destroy(struct psample_group *group) 159 { 160 psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP); 161 list_del(&group->list); 162 kfree_rcu(group, rcu); 163 } 164 165 static struct psample_group * 166 psample_group_lookup(struct net *net, u32 group_num) 167 { 168 struct psample_group *group; 169 170 list_for_each_entry(group, &psample_groups_list, list) 171 if ((group->group_num == group_num) && (group->net == net)) 172 return group; 173 return NULL; 174 } 175 176 struct psample_group *psample_group_get(struct net *net, u32 group_num) 177 { 178 struct psample_group *group; 179 180 spin_lock_bh(&psample_groups_lock); 181 182 group = psample_group_lookup(net, group_num); 183 if (!group) { 184 group = psample_group_create(net, group_num); 185 if (!group) 186 goto out; 187 } 188 group->refcount++; 189 190 out: 191 spin_unlock_bh(&psample_groups_lock); 192 return group; 193 } 194 EXPORT_SYMBOL_GPL(psample_group_get); 195 196 void psample_group_take(struct psample_group *group) 197 { 198 spin_lock_bh(&psample_groups_lock); 199 group->refcount++; 200 spin_unlock_bh(&psample_groups_lock); 201 } 202 EXPORT_SYMBOL_GPL(psample_group_take); 203 204 void psample_group_put(struct psample_group *group) 205 { 206 spin_lock_bh(&psample_groups_lock); 207 208 if (--group->refcount == 0) 209 psample_group_destroy(group); 210 211 spin_unlock_bh(&psample_groups_lock); 212 } 213 EXPORT_SYMBOL_GPL(psample_group_put); 214 215 #ifdef CONFIG_INET 216 static int __psample_ip_tun_to_nlattr(struct sk_buff *skb, 217 struct ip_tunnel_info *tun_info) 218 { 219 unsigned short tun_proto = ip_tunnel_info_af(tun_info); 220 const void *tun_opts = ip_tunnel_info_opts(tun_info); 221 const struct ip_tunnel_key *tun_key = &tun_info->key; 222 int tun_opts_len = tun_info->options_len; 223 224 if (test_bit(IP_TUNNEL_KEY_BIT, tun_key->tun_flags) && 225 nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id, 226 PSAMPLE_TUNNEL_KEY_ATTR_PAD)) 227 return -EMSGSIZE; 228 229 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE && 230 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE)) 231 return -EMSGSIZE; 232 233 switch (tun_proto) { 234 case AF_INET: 235 if (tun_key->u.ipv4.src && 236 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC, 237 tun_key->u.ipv4.src)) 238 return -EMSGSIZE; 239 if (tun_key->u.ipv4.dst && 240 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST, 241 tun_key->u.ipv4.dst)) 242 return -EMSGSIZE; 243 break; 244 case AF_INET6: 245 if (!ipv6_addr_any(&tun_key->u.ipv6.src) && 246 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC, 247 &tun_key->u.ipv6.src)) 248 return -EMSGSIZE; 249 if (!ipv6_addr_any(&tun_key->u.ipv6.dst) && 250 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST, 251 &tun_key->u.ipv6.dst)) 252 return -EMSGSIZE; 253 break; 254 } 255 if (tun_key->tos && 256 nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos)) 257 return -EMSGSIZE; 258 if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl)) 259 return -EMSGSIZE; 260 if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, tun_key->tun_flags) && 261 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT)) 262 return -EMSGSIZE; 263 if (test_bit(IP_TUNNEL_CSUM_BIT, tun_key->tun_flags) && 264 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM)) 265 return -EMSGSIZE; 266 if (tun_key->tp_src && 267 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src)) 268 return -EMSGSIZE; 269 if (tun_key->tp_dst && 270 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst)) 271 return -EMSGSIZE; 272 if (test_bit(IP_TUNNEL_OAM_BIT, tun_key->tun_flags) && 273 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM)) 274 return -EMSGSIZE; 275 if (tun_opts_len) { 276 if (test_bit(IP_TUNNEL_GENEVE_OPT_BIT, tun_key->tun_flags) && 277 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS, 278 tun_opts_len, tun_opts)) 279 return -EMSGSIZE; 280 else if (test_bit(IP_TUNNEL_ERSPAN_OPT_BIT, 281 tun_key->tun_flags) && 282 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS, 283 tun_opts_len, tun_opts)) 284 return -EMSGSIZE; 285 } 286 287 return 0; 288 } 289 290 static int psample_ip_tun_to_nlattr(struct sk_buff *skb, 291 struct ip_tunnel_info *tun_info) 292 { 293 struct nlattr *nla; 294 int err; 295 296 nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL); 297 if (!nla) 298 return -EMSGSIZE; 299 300 err = __psample_ip_tun_to_nlattr(skb, tun_info); 301 if (err) { 302 nla_nest_cancel(skb, nla); 303 return err; 304 } 305 306 nla_nest_end(skb, nla); 307 308 return 0; 309 } 310 311 static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info) 312 { 313 unsigned short tun_proto = ip_tunnel_info_af(tun_info); 314 const struct ip_tunnel_key *tun_key = &tun_info->key; 315 int tun_opts_len = tun_info->options_len; 316 int sum = nla_total_size(0); /* PSAMPLE_ATTR_TUNNEL */ 317 318 if (test_bit(IP_TUNNEL_KEY_BIT, tun_key->tun_flags)) 319 sum += nla_total_size_64bit(sizeof(u64)); 320 321 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE) 322 sum += nla_total_size(0); 323 324 switch (tun_proto) { 325 case AF_INET: 326 if (tun_key->u.ipv4.src) 327 sum += nla_total_size(sizeof(u32)); 328 if (tun_key->u.ipv4.dst) 329 sum += nla_total_size(sizeof(u32)); 330 break; 331 case AF_INET6: 332 if (!ipv6_addr_any(&tun_key->u.ipv6.src)) 333 sum += nla_total_size(sizeof(struct in6_addr)); 334 if (!ipv6_addr_any(&tun_key->u.ipv6.dst)) 335 sum += nla_total_size(sizeof(struct in6_addr)); 336 break; 337 } 338 if (tun_key->tos) 339 sum += nla_total_size(sizeof(u8)); 340 sum += nla_total_size(sizeof(u8)); /* TTL */ 341 if (test_bit(IP_TUNNEL_DONT_FRAGMENT_BIT, tun_key->tun_flags)) 342 sum += nla_total_size(0); 343 if (test_bit(IP_TUNNEL_CSUM_BIT, tun_key->tun_flags)) 344 sum += nla_total_size(0); 345 if (tun_key->tp_src) 346 sum += nla_total_size(sizeof(u16)); 347 if (tun_key->tp_dst) 348 sum += nla_total_size(sizeof(u16)); 349 if (test_bit(IP_TUNNEL_OAM_BIT, tun_key->tun_flags)) 350 sum += nla_total_size(0); 351 if (tun_opts_len) { 352 if (test_bit(IP_TUNNEL_GENEVE_OPT_BIT, tun_key->tun_flags)) 353 sum += nla_total_size(tun_opts_len); 354 else if (test_bit(IP_TUNNEL_ERSPAN_OPT_BIT, 355 tun_key->tun_flags)) 356 sum += nla_total_size(tun_opts_len); 357 } 358 359 return sum; 360 } 361 #endif 362 363 void psample_sample_packet(struct psample_group *group, 364 const struct sk_buff *skb, u32 sample_rate, 365 const struct psample_metadata *md) 366 { 367 ktime_t tstamp = ktime_get_real(); 368 int out_ifindex = md->out_ifindex; 369 int in_ifindex = md->in_ifindex; 370 u32 trunc_size = md->trunc_size; 371 #ifdef CONFIG_INET 372 struct ip_tunnel_info *tun_info; 373 #endif 374 struct sk_buff *nl_skb; 375 int data_len; 376 int meta_len; 377 void *data; 378 int ret; 379 380 if (!genl_has_listeners(&psample_nl_family, group->net, 381 PSAMPLE_NL_MCGRP_SAMPLE)) 382 return; 383 384 meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) + 385 (out_ifindex ? nla_total_size(sizeof(u16)) : 0) + 386 (md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) + 387 (md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) + 388 (md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) + 389 nla_total_size(sizeof(u32)) + /* sample_rate */ 390 nla_total_size(sizeof(u32)) + /* orig_size */ 391 nla_total_size(sizeof(u32)) + /* group_num */ 392 nla_total_size(sizeof(u32)) + /* seq */ 393 nla_total_size_64bit(sizeof(u64)) + /* timestamp */ 394 nla_total_size(sizeof(u16)) + /* protocol */ 395 (md->user_cookie_len ? 396 nla_total_size(md->user_cookie_len) : 0); /* user cookie */ 397 398 #ifdef CONFIG_INET 399 tun_info = skb_tunnel_info(skb); 400 if (tun_info) 401 meta_len += psample_tunnel_meta_len(tun_info); 402 #endif 403 404 data_len = min(skb->len, trunc_size); 405 if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE) 406 data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN 407 - NLA_ALIGNTO; 408 409 nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC); 410 if (unlikely(!nl_skb)) 411 return; 412 413 data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0, 414 PSAMPLE_CMD_SAMPLE); 415 if (unlikely(!data)) 416 goto error; 417 418 if (in_ifindex) { 419 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex); 420 if (unlikely(ret < 0)) 421 goto error; 422 } 423 424 if (out_ifindex) { 425 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex); 426 if (unlikely(ret < 0)) 427 goto error; 428 } 429 430 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate); 431 if (unlikely(ret < 0)) 432 goto error; 433 434 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len); 435 if (unlikely(ret < 0)) 436 goto error; 437 438 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num); 439 if (unlikely(ret < 0)) 440 goto error; 441 442 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++); 443 if (unlikely(ret < 0)) 444 goto error; 445 446 if (md->out_tc_valid) { 447 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc); 448 if (unlikely(ret < 0)) 449 goto error; 450 } 451 452 if (md->out_tc_occ_valid) { 453 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC, 454 md->out_tc_occ, PSAMPLE_ATTR_PAD); 455 if (unlikely(ret < 0)) 456 goto error; 457 } 458 459 if (md->latency_valid) { 460 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY, 461 md->latency, PSAMPLE_ATTR_PAD); 462 if (unlikely(ret < 0)) 463 goto error; 464 } 465 466 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP, 467 ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD); 468 if (unlikely(ret < 0)) 469 goto error; 470 471 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO, 472 be16_to_cpu(skb->protocol)); 473 if (unlikely(ret < 0)) 474 goto error; 475 476 if (data_len) { 477 int nla_len = nla_total_size(data_len); 478 struct nlattr *nla; 479 480 nla = skb_put(nl_skb, nla_len); 481 nla->nla_type = PSAMPLE_ATTR_DATA; 482 nla->nla_len = nla_attr_size(data_len); 483 484 if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) 485 goto error; 486 } 487 488 #ifdef CONFIG_INET 489 if (tun_info) { 490 ret = psample_ip_tun_to_nlattr(nl_skb, tun_info); 491 if (unlikely(ret < 0)) 492 goto error; 493 } 494 #endif 495 496 if (md->user_cookie && md->user_cookie_len && 497 nla_put(nl_skb, PSAMPLE_ATTR_USER_COOKIE, md->user_cookie_len, 498 md->user_cookie)) 499 goto error; 500 501 if (md->rate_as_probability) 502 nla_put_flag(nl_skb, PSAMPLE_ATTR_SAMPLE_PROBABILITY); 503 504 genlmsg_end(nl_skb, data); 505 genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0, 506 PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC); 507 508 return; 509 error: 510 pr_err_ratelimited("Could not create psample log message\n"); 511 nlmsg_free(nl_skb); 512 } 513 EXPORT_SYMBOL_GPL(psample_sample_packet); 514 515 static int __init psample_module_init(void) 516 { 517 return genl_register_family(&psample_nl_family); 518 } 519 520 static void __exit psample_module_exit(void) 521 { 522 genl_unregister_family(&psample_nl_family); 523 } 524 525 module_init(psample_module_init); 526 module_exit(psample_module_exit); 527 528 MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 529 MODULE_DESCRIPTION("netlink channel for packet sampling"); 530 MODULE_LICENSE("GPL v2"); 531