psample.c (13393B)
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 23static LIST_HEAD(psample_groups_list); 24static DEFINE_SPINLOCK(psample_groups_lock); 25 26/* multicast groups */ 27enum psample_nl_multicast_groups { 28 PSAMPLE_NL_MCGRP_CONFIG, 29 PSAMPLE_NL_MCGRP_SAMPLE, 30}; 31 32static 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 37static struct genl_family psample_nl_family __ro_after_init; 38 39static 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 66error: 67 genlmsg_cancel(msg, hdr); 68 return -EMSGSIZE; 69} 70 71static 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 100static 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 109static 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 .n_mcgrps = ARRAY_SIZE(psample_nl_mcgrps), 119}; 120 121static void psample_group_notify(struct psample_group *group, 122 enum psample_command cmd) 123{ 124 struct sk_buff *msg; 125 int err; 126 127 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); 128 if (!msg) 129 return; 130 131 err = psample_group_nl_fill(msg, group, cmd, 0, 0, NLM_F_MULTI); 132 if (!err) 133 genlmsg_multicast_netns(&psample_nl_family, group->net, msg, 0, 134 PSAMPLE_NL_MCGRP_CONFIG, GFP_ATOMIC); 135 else 136 nlmsg_free(msg); 137} 138 139static struct psample_group *psample_group_create(struct net *net, 140 u32 group_num) 141{ 142 struct psample_group *group; 143 144 group = kzalloc(sizeof(*group), GFP_ATOMIC); 145 if (!group) 146 return NULL; 147 148 group->net = net; 149 group->group_num = group_num; 150 list_add_tail(&group->list, &psample_groups_list); 151 152 psample_group_notify(group, PSAMPLE_CMD_NEW_GROUP); 153 return group; 154} 155 156static void psample_group_destroy(struct psample_group *group) 157{ 158 psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP); 159 list_del(&group->list); 160 kfree_rcu(group, rcu); 161} 162 163static struct psample_group * 164psample_group_lookup(struct net *net, u32 group_num) 165{ 166 struct psample_group *group; 167 168 list_for_each_entry(group, &psample_groups_list, list) 169 if ((group->group_num == group_num) && (group->net == net)) 170 return group; 171 return NULL; 172} 173 174struct psample_group *psample_group_get(struct net *net, u32 group_num) 175{ 176 struct psample_group *group; 177 178 spin_lock_bh(&psample_groups_lock); 179 180 group = psample_group_lookup(net, group_num); 181 if (!group) { 182 group = psample_group_create(net, group_num); 183 if (!group) 184 goto out; 185 } 186 group->refcount++; 187 188out: 189 spin_unlock_bh(&psample_groups_lock); 190 return group; 191} 192EXPORT_SYMBOL_GPL(psample_group_get); 193 194void psample_group_take(struct psample_group *group) 195{ 196 spin_lock_bh(&psample_groups_lock); 197 group->refcount++; 198 spin_unlock_bh(&psample_groups_lock); 199} 200EXPORT_SYMBOL_GPL(psample_group_take); 201 202void psample_group_put(struct psample_group *group) 203{ 204 spin_lock_bh(&psample_groups_lock); 205 206 if (--group->refcount == 0) 207 psample_group_destroy(group); 208 209 spin_unlock_bh(&psample_groups_lock); 210} 211EXPORT_SYMBOL_GPL(psample_group_put); 212 213#ifdef CONFIG_INET 214static int __psample_ip_tun_to_nlattr(struct sk_buff *skb, 215 struct ip_tunnel_info *tun_info) 216{ 217 unsigned short tun_proto = ip_tunnel_info_af(tun_info); 218 const void *tun_opts = ip_tunnel_info_opts(tun_info); 219 const struct ip_tunnel_key *tun_key = &tun_info->key; 220 int tun_opts_len = tun_info->options_len; 221 222 if (tun_key->tun_flags & TUNNEL_KEY && 223 nla_put_be64(skb, PSAMPLE_TUNNEL_KEY_ATTR_ID, tun_key->tun_id, 224 PSAMPLE_TUNNEL_KEY_ATTR_PAD)) 225 return -EMSGSIZE; 226 227 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE && 228 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE)) 229 return -EMSGSIZE; 230 231 switch (tun_proto) { 232 case AF_INET: 233 if (tun_key->u.ipv4.src && 234 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_SRC, 235 tun_key->u.ipv4.src)) 236 return -EMSGSIZE; 237 if (tun_key->u.ipv4.dst && 238 nla_put_in_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV4_DST, 239 tun_key->u.ipv4.dst)) 240 return -EMSGSIZE; 241 break; 242 case AF_INET6: 243 if (!ipv6_addr_any(&tun_key->u.ipv6.src) && 244 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_SRC, 245 &tun_key->u.ipv6.src)) 246 return -EMSGSIZE; 247 if (!ipv6_addr_any(&tun_key->u.ipv6.dst) && 248 nla_put_in6_addr(skb, PSAMPLE_TUNNEL_KEY_ATTR_IPV6_DST, 249 &tun_key->u.ipv6.dst)) 250 return -EMSGSIZE; 251 break; 252 } 253 if (tun_key->tos && 254 nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TOS, tun_key->tos)) 255 return -EMSGSIZE; 256 if (nla_put_u8(skb, PSAMPLE_TUNNEL_KEY_ATTR_TTL, tun_key->ttl)) 257 return -EMSGSIZE; 258 if ((tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) && 259 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_DONT_FRAGMENT)) 260 return -EMSGSIZE; 261 if ((tun_key->tun_flags & TUNNEL_CSUM) && 262 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_CSUM)) 263 return -EMSGSIZE; 264 if (tun_key->tp_src && 265 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_SRC, tun_key->tp_src)) 266 return -EMSGSIZE; 267 if (tun_key->tp_dst && 268 nla_put_be16(skb, PSAMPLE_TUNNEL_KEY_ATTR_TP_DST, tun_key->tp_dst)) 269 return -EMSGSIZE; 270 if ((tun_key->tun_flags & TUNNEL_OAM) && 271 nla_put_flag(skb, PSAMPLE_TUNNEL_KEY_ATTR_OAM)) 272 return -EMSGSIZE; 273 if (tun_opts_len) { 274 if (tun_key->tun_flags & TUNNEL_GENEVE_OPT && 275 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_GENEVE_OPTS, 276 tun_opts_len, tun_opts)) 277 return -EMSGSIZE; 278 else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT && 279 nla_put(skb, PSAMPLE_TUNNEL_KEY_ATTR_ERSPAN_OPTS, 280 tun_opts_len, tun_opts)) 281 return -EMSGSIZE; 282 } 283 284 return 0; 285} 286 287static int psample_ip_tun_to_nlattr(struct sk_buff *skb, 288 struct ip_tunnel_info *tun_info) 289{ 290 struct nlattr *nla; 291 int err; 292 293 nla = nla_nest_start_noflag(skb, PSAMPLE_ATTR_TUNNEL); 294 if (!nla) 295 return -EMSGSIZE; 296 297 err = __psample_ip_tun_to_nlattr(skb, tun_info); 298 if (err) { 299 nla_nest_cancel(skb, nla); 300 return err; 301 } 302 303 nla_nest_end(skb, nla); 304 305 return 0; 306} 307 308static int psample_tunnel_meta_len(struct ip_tunnel_info *tun_info) 309{ 310 unsigned short tun_proto = ip_tunnel_info_af(tun_info); 311 const struct ip_tunnel_key *tun_key = &tun_info->key; 312 int tun_opts_len = tun_info->options_len; 313 int sum = nla_total_size(0); /* PSAMPLE_ATTR_TUNNEL */ 314 315 if (tun_key->tun_flags & TUNNEL_KEY) 316 sum += nla_total_size_64bit(sizeof(u64)); 317 318 if (tun_info->mode & IP_TUNNEL_INFO_BRIDGE) 319 sum += nla_total_size(0); 320 321 switch (tun_proto) { 322 case AF_INET: 323 if (tun_key->u.ipv4.src) 324 sum += nla_total_size(sizeof(u32)); 325 if (tun_key->u.ipv4.dst) 326 sum += nla_total_size(sizeof(u32)); 327 break; 328 case AF_INET6: 329 if (!ipv6_addr_any(&tun_key->u.ipv6.src)) 330 sum += nla_total_size(sizeof(struct in6_addr)); 331 if (!ipv6_addr_any(&tun_key->u.ipv6.dst)) 332 sum += nla_total_size(sizeof(struct in6_addr)); 333 break; 334 } 335 if (tun_key->tos) 336 sum += nla_total_size(sizeof(u8)); 337 sum += nla_total_size(sizeof(u8)); /* TTL */ 338 if (tun_key->tun_flags & TUNNEL_DONT_FRAGMENT) 339 sum += nla_total_size(0); 340 if (tun_key->tun_flags & TUNNEL_CSUM) 341 sum += nla_total_size(0); 342 if (tun_key->tp_src) 343 sum += nla_total_size(sizeof(u16)); 344 if (tun_key->tp_dst) 345 sum += nla_total_size(sizeof(u16)); 346 if (tun_key->tun_flags & TUNNEL_OAM) 347 sum += nla_total_size(0); 348 if (tun_opts_len) { 349 if (tun_key->tun_flags & TUNNEL_GENEVE_OPT) 350 sum += nla_total_size(tun_opts_len); 351 else if (tun_key->tun_flags & TUNNEL_ERSPAN_OPT) 352 sum += nla_total_size(tun_opts_len); 353 } 354 355 return sum; 356} 357#endif 358 359void psample_sample_packet(struct psample_group *group, struct sk_buff *skb, 360 u32 sample_rate, const struct psample_metadata *md) 361{ 362 ktime_t tstamp = ktime_get_real(); 363 int out_ifindex = md->out_ifindex; 364 int in_ifindex = md->in_ifindex; 365 u32 trunc_size = md->trunc_size; 366#ifdef CONFIG_INET 367 struct ip_tunnel_info *tun_info; 368#endif 369 struct sk_buff *nl_skb; 370 int data_len; 371 int meta_len; 372 void *data; 373 int ret; 374 375 meta_len = (in_ifindex ? nla_total_size(sizeof(u16)) : 0) + 376 (out_ifindex ? nla_total_size(sizeof(u16)) : 0) + 377 (md->out_tc_valid ? nla_total_size(sizeof(u16)) : 0) + 378 (md->out_tc_occ_valid ? nla_total_size_64bit(sizeof(u64)) : 0) + 379 (md->latency_valid ? nla_total_size_64bit(sizeof(u64)) : 0) + 380 nla_total_size(sizeof(u32)) + /* sample_rate */ 381 nla_total_size(sizeof(u32)) + /* orig_size */ 382 nla_total_size(sizeof(u32)) + /* group_num */ 383 nla_total_size(sizeof(u32)) + /* seq */ 384 nla_total_size_64bit(sizeof(u64)) + /* timestamp */ 385 nla_total_size(sizeof(u16)); /* protocol */ 386 387#ifdef CONFIG_INET 388 tun_info = skb_tunnel_info(skb); 389 if (tun_info) 390 meta_len += psample_tunnel_meta_len(tun_info); 391#endif 392 393 data_len = min(skb->len, trunc_size); 394 if (meta_len + nla_total_size(data_len) > PSAMPLE_MAX_PACKET_SIZE) 395 data_len = PSAMPLE_MAX_PACKET_SIZE - meta_len - NLA_HDRLEN 396 - NLA_ALIGNTO; 397 398 nl_skb = genlmsg_new(meta_len + nla_total_size(data_len), GFP_ATOMIC); 399 if (unlikely(!nl_skb)) 400 return; 401 402 data = genlmsg_put(nl_skb, 0, 0, &psample_nl_family, 0, 403 PSAMPLE_CMD_SAMPLE); 404 if (unlikely(!data)) 405 goto error; 406 407 if (in_ifindex) { 408 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_IIFINDEX, in_ifindex); 409 if (unlikely(ret < 0)) 410 goto error; 411 } 412 413 if (out_ifindex) { 414 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OIFINDEX, out_ifindex); 415 if (unlikely(ret < 0)) 416 goto error; 417 } 418 419 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_RATE, sample_rate); 420 if (unlikely(ret < 0)) 421 goto error; 422 423 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_ORIGSIZE, skb->len); 424 if (unlikely(ret < 0)) 425 goto error; 426 427 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_SAMPLE_GROUP, group->group_num); 428 if (unlikely(ret < 0)) 429 goto error; 430 431 ret = nla_put_u32(nl_skb, PSAMPLE_ATTR_GROUP_SEQ, group->seq++); 432 if (unlikely(ret < 0)) 433 goto error; 434 435 if (md->out_tc_valid) { 436 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_OUT_TC, md->out_tc); 437 if (unlikely(ret < 0)) 438 goto error; 439 } 440 441 if (md->out_tc_occ_valid) { 442 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_OUT_TC_OCC, 443 md->out_tc_occ, PSAMPLE_ATTR_PAD); 444 if (unlikely(ret < 0)) 445 goto error; 446 } 447 448 if (md->latency_valid) { 449 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_LATENCY, 450 md->latency, PSAMPLE_ATTR_PAD); 451 if (unlikely(ret < 0)) 452 goto error; 453 } 454 455 ret = nla_put_u64_64bit(nl_skb, PSAMPLE_ATTR_TIMESTAMP, 456 ktime_to_ns(tstamp), PSAMPLE_ATTR_PAD); 457 if (unlikely(ret < 0)) 458 goto error; 459 460 ret = nla_put_u16(nl_skb, PSAMPLE_ATTR_PROTO, 461 be16_to_cpu(skb->protocol)); 462 if (unlikely(ret < 0)) 463 goto error; 464 465 if (data_len) { 466 int nla_len = nla_total_size(data_len); 467 struct nlattr *nla; 468 469 nla = skb_put(nl_skb, nla_len); 470 nla->nla_type = PSAMPLE_ATTR_DATA; 471 nla->nla_len = nla_attr_size(data_len); 472 473 if (skb_copy_bits(skb, 0, nla_data(nla), data_len)) 474 goto error; 475 } 476 477#ifdef CONFIG_INET 478 if (tun_info) { 479 ret = psample_ip_tun_to_nlattr(nl_skb, tun_info); 480 if (unlikely(ret < 0)) 481 goto error; 482 } 483#endif 484 485 genlmsg_end(nl_skb, data); 486 genlmsg_multicast_netns(&psample_nl_family, group->net, nl_skb, 0, 487 PSAMPLE_NL_MCGRP_SAMPLE, GFP_ATOMIC); 488 489 return; 490error: 491 pr_err_ratelimited("Could not create psample log message\n"); 492 nlmsg_free(nl_skb); 493} 494EXPORT_SYMBOL_GPL(psample_sample_packet); 495 496static int __init psample_module_init(void) 497{ 498 return genl_register_family(&psample_nl_family); 499} 500 501static void __exit psample_module_exit(void) 502{ 503 genl_unregister_family(&psample_nl_family); 504} 505 506module_init(psample_module_init); 507module_exit(psample_module_exit); 508 509MODULE_AUTHOR("Yotam Gigi <yotam.gi@gmail.com>"); 510MODULE_DESCRIPTION("netlink channel for packet sampling"); 511MODULE_LICENSE("GPL v2");