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