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