1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* GTP according to GSM TS 09.60 / 3GPP TS 29.060 3 * 4 * (C) 2012-2014 by sysmocom - s.f.m.c. GmbH 5 * (C) 2016 by Pablo Neira Ayuso <pablo@netfilter.org> 6 * 7 * Author: Harald Welte <hwelte@sysmocom.de> 8 * Pablo Neira Ayuso <pablo@netfilter.org> 9 * Andreas Schultz <aschultz@travelping.com> 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/module.h> 15 #include <linux/skbuff.h> 16 #include <linux/udp.h> 17 #include <linux/rculist.h> 18 #include <linux/jhash.h> 19 #include <linux/if_tunnel.h> 20 #include <linux/net.h> 21 #include <linux/file.h> 22 #include <linux/gtp.h> 23 24 #include <net/net_namespace.h> 25 #include <net/protocol.h> 26 #include <net/ip.h> 27 #include <net/udp.h> 28 #include <net/udp_tunnel.h> 29 #include <net/icmp.h> 30 #include <net/xfrm.h> 31 #include <net/genetlink.h> 32 #include <net/netns/generic.h> 33 #include <net/gtp.h> 34 35 /* An active session for the subscriber. */ 36 struct pdp_ctx { 37 struct hlist_node hlist_tid; 38 struct hlist_node hlist_addr; 39 40 union { 41 struct { 42 u64 tid; 43 u16 flow; 44 } v0; 45 struct { 46 u32 i_tei; 47 u32 o_tei; 48 } v1; 49 } u; 50 u8 gtp_version; 51 u16 af; 52 53 struct in_addr ms_addr_ip4; 54 struct in_addr peer_addr_ip4; 55 56 struct sock *sk; 57 struct net_device *dev; 58 59 atomic_t tx_seq; 60 struct rcu_head rcu_head; 61 }; 62 63 /* One instance of the GTP device. */ 64 struct gtp_dev { 65 struct list_head list; 66 67 struct sock *sk0; 68 struct sock *sk1u; 69 u8 sk_created; 70 71 struct net_device *dev; 72 struct net *net; 73 74 unsigned int role; 75 unsigned int hash_size; 76 struct hlist_head *tid_hash; 77 struct hlist_head *addr_hash; 78 79 u8 restart_count; 80 }; 81 82 struct echo_info { 83 struct in_addr ms_addr_ip4; 84 struct in_addr peer_addr_ip4; 85 u8 gtp_version; 86 }; 87 88 static unsigned int gtp_net_id __read_mostly; 89 90 struct gtp_net { 91 struct list_head gtp_dev_list; 92 }; 93 94 static u32 gtp_h_initval; 95 96 static struct genl_family gtp_genl_family; 97 98 enum gtp_multicast_groups { 99 GTP_GENL_MCGRP, 100 }; 101 102 static const struct genl_multicast_group gtp_genl_mcgrps[] = { 103 [GTP_GENL_MCGRP] = { .name = GTP_GENL_MCGRP_NAME }, 104 }; 105 106 static void pdp_context_delete(struct pdp_ctx *pctx); 107 108 static inline u32 gtp0_hashfn(u64 tid) 109 { 110 u32 *tid32 = (u32 *) &tid; 111 return jhash_2words(tid32[0], tid32[1], gtp_h_initval); 112 } 113 114 static inline u32 gtp1u_hashfn(u32 tid) 115 { 116 return jhash_1word(tid, gtp_h_initval); 117 } 118 119 static inline u32 ipv4_hashfn(__be32 ip) 120 { 121 return jhash_1word((__force u32)ip, gtp_h_initval); 122 } 123 124 /* Resolve a PDP context structure based on the 64bit TID. */ 125 static struct pdp_ctx *gtp0_pdp_find(struct gtp_dev *gtp, u64 tid) 126 { 127 struct hlist_head *head; 128 struct pdp_ctx *pdp; 129 130 head = >p->tid_hash[gtp0_hashfn(tid) % gtp->hash_size]; 131 132 hlist_for_each_entry_rcu(pdp, head, hlist_tid) { 133 if (pdp->gtp_version == GTP_V0 && 134 pdp->u.v0.tid == tid) 135 return pdp; 136 } 137 return NULL; 138 } 139 140 /* Resolve a PDP context structure based on the 32bit TEI. */ 141 static struct pdp_ctx *gtp1_pdp_find(struct gtp_dev *gtp, u32 tid) 142 { 143 struct hlist_head *head; 144 struct pdp_ctx *pdp; 145 146 head = >p->tid_hash[gtp1u_hashfn(tid) % gtp->hash_size]; 147 148 hlist_for_each_entry_rcu(pdp, head, hlist_tid) { 149 if (pdp->gtp_version == GTP_V1 && 150 pdp->u.v1.i_tei == tid) 151 return pdp; 152 } 153 return NULL; 154 } 155 156 /* Resolve a PDP context based on IPv4 address of MS. */ 157 static struct pdp_ctx *ipv4_pdp_find(struct gtp_dev *gtp, __be32 ms_addr) 158 { 159 struct hlist_head *head; 160 struct pdp_ctx *pdp; 161 162 head = >p->addr_hash[ipv4_hashfn(ms_addr) % gtp->hash_size]; 163 164 hlist_for_each_entry_rcu(pdp, head, hlist_addr) { 165 if (pdp->af == AF_INET && 166 pdp->ms_addr_ip4.s_addr == ms_addr) 167 return pdp; 168 } 169 170 return NULL; 171 } 172 173 static bool gtp_check_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx, 174 unsigned int hdrlen, unsigned int role) 175 { 176 struct iphdr *iph; 177 178 if (!pskb_may_pull(skb, hdrlen + sizeof(struct iphdr))) 179 return false; 180 181 iph = (struct iphdr *)(skb->data + hdrlen); 182 183 if (role == GTP_ROLE_SGSN) 184 return iph->daddr == pctx->ms_addr_ip4.s_addr; 185 else 186 return iph->saddr == pctx->ms_addr_ip4.s_addr; 187 } 188 189 /* Check if the inner IP address in this packet is assigned to any 190 * existing mobile subscriber. 191 */ 192 static bool gtp_check_ms(struct sk_buff *skb, struct pdp_ctx *pctx, 193 unsigned int hdrlen, unsigned int role) 194 { 195 switch (ntohs(skb->protocol)) { 196 case ETH_P_IP: 197 return gtp_check_ms_ipv4(skb, pctx, hdrlen, role); 198 } 199 return false; 200 } 201 202 static int gtp_rx(struct pdp_ctx *pctx, struct sk_buff *skb, 203 unsigned int hdrlen, unsigned int role) 204 { 205 if (!gtp_check_ms(skb, pctx, hdrlen, role)) { 206 netdev_dbg(pctx->dev, "No PDP ctx for this MS\n"); 207 return 1; 208 } 209 210 /* Get rid of the GTP + UDP headers. */ 211 if (iptunnel_pull_header(skb, hdrlen, skb->protocol, 212 !net_eq(sock_net(pctx->sk), dev_net(pctx->dev)))) { 213 pctx->dev->stats.rx_length_errors++; 214 goto err; 215 } 216 217 netdev_dbg(pctx->dev, "forwarding packet from GGSN to uplink\n"); 218 219 /* Now that the UDP and the GTP header have been removed, set up the 220 * new network header. This is required by the upper layer to 221 * calculate the transport header. 222 */ 223 skb_reset_network_header(skb); 224 skb_reset_mac_header(skb); 225 226 skb->dev = pctx->dev; 227 228 dev_sw_netstats_rx_add(pctx->dev, skb->len); 229 230 __netif_rx(skb); 231 return 0; 232 233 err: 234 pctx->dev->stats.rx_dropped++; 235 return -1; 236 } 237 238 static struct rtable *ip4_route_output_gtp(struct flowi4 *fl4, 239 const struct sock *sk, 240 __be32 daddr, __be32 saddr) 241 { 242 memset(fl4, 0, sizeof(*fl4)); 243 fl4->flowi4_oif = sk->sk_bound_dev_if; 244 fl4->daddr = daddr; 245 fl4->saddr = saddr; 246 fl4->flowi4_tos = ip_sock_rt_tos(sk); 247 fl4->flowi4_scope = ip_sock_rt_scope(sk); 248 fl4->flowi4_proto = sk->sk_protocol; 249 250 return ip_route_output_key(sock_net(sk), fl4); 251 } 252 253 /* GSM TS 09.60. 7.3 254 * In all Path Management messages: 255 * - TID: is not used and shall be set to 0. 256 * - Flow Label is not used and shall be set to 0 257 * In signalling messages: 258 * - number: this field is not yet used in signalling messages. 259 * It shall be set to 255 by the sender and shall be ignored 260 * by the receiver 261 * Returns true if the echo req was correct, false otherwise. 262 */ 263 static bool gtp0_validate_echo_hdr(struct gtp0_header *gtp0) 264 { 265 return !(gtp0->tid || (gtp0->flags ^ 0x1e) || 266 gtp0->number != 0xff || gtp0->flow); 267 } 268 269 /* msg_type has to be GTP_ECHO_REQ or GTP_ECHO_RSP */ 270 static void gtp0_build_echo_msg(struct gtp0_header *hdr, __u8 msg_type) 271 { 272 int len_pkt, len_hdr; 273 274 hdr->flags = 0x1e; /* v0, GTP-non-prime. */ 275 hdr->type = msg_type; 276 /* GSM TS 09.60. 7.3 In all Path Management Flow Label and TID 277 * are not used and shall be set to 0. 278 */ 279 hdr->flow = 0; 280 hdr->tid = 0; 281 hdr->number = 0xff; 282 hdr->spare[0] = 0xff; 283 hdr->spare[1] = 0xff; 284 hdr->spare[2] = 0xff; 285 286 len_pkt = sizeof(struct gtp0_packet); 287 len_hdr = sizeof(struct gtp0_header); 288 289 if (msg_type == GTP_ECHO_RSP) 290 hdr->length = htons(len_pkt - len_hdr); 291 else 292 hdr->length = 0; 293 } 294 295 static int gtp0_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) 296 { 297 struct gtp0_packet *gtp_pkt; 298 struct gtp0_header *gtp0; 299 struct rtable *rt; 300 struct flowi4 fl4; 301 struct iphdr *iph; 302 __be16 seq; 303 304 gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr)); 305 306 if (!gtp0_validate_echo_hdr(gtp0)) 307 return -1; 308 309 seq = gtp0->seq; 310 311 /* pull GTP and UDP headers */ 312 skb_pull_data(skb, sizeof(struct gtp0_header) + sizeof(struct udphdr)); 313 314 gtp_pkt = skb_push(skb, sizeof(struct gtp0_packet)); 315 memset(gtp_pkt, 0, sizeof(struct gtp0_packet)); 316 317 gtp0_build_echo_msg(>p_pkt->gtp0_h, GTP_ECHO_RSP); 318 319 /* GSM TS 09.60. 7.3 The Sequence Number in a signalling response 320 * message shall be copied from the signalling request message 321 * that the GSN is replying to. 322 */ 323 gtp_pkt->gtp0_h.seq = seq; 324 325 gtp_pkt->ie.tag = GTPIE_RECOVERY; 326 gtp_pkt->ie.val = gtp->restart_count; 327 328 iph = ip_hdr(skb); 329 330 /* find route to the sender, 331 * src address becomes dst address and vice versa. 332 */ 333 rt = ip4_route_output_gtp(&fl4, gtp->sk0, iph->saddr, iph->daddr); 334 if (IS_ERR(rt)) { 335 netdev_dbg(gtp->dev, "no route for echo response from %pI4\n", 336 &iph->saddr); 337 return -1; 338 } 339 340 udp_tunnel_xmit_skb(rt, gtp->sk0, skb, 341 fl4.saddr, fl4.daddr, 342 iph->tos, 343 ip4_dst_hoplimit(&rt->dst), 344 0, 345 htons(GTP0_PORT), htons(GTP0_PORT), 346 !net_eq(sock_net(gtp->sk1u), 347 dev_net(gtp->dev)), 348 false); 349 return 0; 350 } 351 352 static int gtp_genl_fill_echo(struct sk_buff *skb, u32 snd_portid, u32 snd_seq, 353 int flags, u32 type, struct echo_info echo) 354 { 355 void *genlh; 356 357 genlh = genlmsg_put(skb, snd_portid, snd_seq, >p_genl_family, flags, 358 type); 359 if (!genlh) 360 goto failure; 361 362 if (nla_put_u32(skb, GTPA_VERSION, echo.gtp_version) || 363 nla_put_be32(skb, GTPA_PEER_ADDRESS, echo.peer_addr_ip4.s_addr) || 364 nla_put_be32(skb, GTPA_MS_ADDRESS, echo.ms_addr_ip4.s_addr)) 365 goto failure; 366 367 genlmsg_end(skb, genlh); 368 return 0; 369 370 failure: 371 genlmsg_cancel(skb, genlh); 372 return -EMSGSIZE; 373 } 374 375 static int gtp0_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) 376 { 377 struct gtp0_header *gtp0; 378 struct echo_info echo; 379 struct sk_buff *msg; 380 struct iphdr *iph; 381 int ret; 382 383 gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr)); 384 385 if (!gtp0_validate_echo_hdr(gtp0)) 386 return -1; 387 388 iph = ip_hdr(skb); 389 echo.ms_addr_ip4.s_addr = iph->daddr; 390 echo.peer_addr_ip4.s_addr = iph->saddr; 391 echo.gtp_version = GTP_V0; 392 393 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); 394 if (!msg) 395 return -ENOMEM; 396 397 ret = gtp_genl_fill_echo(msg, 0, 0, 0, GTP_CMD_ECHOREQ, echo); 398 if (ret < 0) { 399 nlmsg_free(msg); 400 return ret; 401 } 402 403 return genlmsg_multicast_netns(>p_genl_family, dev_net(gtp->dev), 404 msg, 0, GTP_GENL_MCGRP, GFP_ATOMIC); 405 } 406 407 /* 1 means pass up to the stack, -1 means drop and 0 means decapsulated. */ 408 static int gtp0_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) 409 { 410 unsigned int hdrlen = sizeof(struct udphdr) + 411 sizeof(struct gtp0_header); 412 struct gtp0_header *gtp0; 413 struct pdp_ctx *pctx; 414 415 if (!pskb_may_pull(skb, hdrlen)) 416 return -1; 417 418 gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr)); 419 420 if ((gtp0->flags >> 5) != GTP_V0) 421 return 1; 422 423 /* If the sockets were created in kernel, it means that 424 * there is no daemon running in userspace which would 425 * handle echo request. 426 */ 427 if (gtp0->type == GTP_ECHO_REQ && gtp->sk_created) 428 return gtp0_send_echo_resp(gtp, skb); 429 430 if (gtp0->type == GTP_ECHO_RSP && gtp->sk_created) 431 return gtp0_handle_echo_resp(gtp, skb); 432 433 if (gtp0->type != GTP_TPDU) 434 return 1; 435 436 pctx = gtp0_pdp_find(gtp, be64_to_cpu(gtp0->tid)); 437 if (!pctx) { 438 netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb); 439 return 1; 440 } 441 442 return gtp_rx(pctx, skb, hdrlen, gtp->role); 443 } 444 445 /* msg_type has to be GTP_ECHO_REQ or GTP_ECHO_RSP */ 446 static void gtp1u_build_echo_msg(struct gtp1_header_long *hdr, __u8 msg_type) 447 { 448 int len_pkt, len_hdr; 449 450 /* S flag must be set to 1 */ 451 hdr->flags = 0x32; /* v1, GTP-non-prime. */ 452 hdr->type = msg_type; 453 /* 3GPP TS 29.281 5.1 - TEID has to be set to 0 */ 454 hdr->tid = 0; 455 456 /* seq, npdu and next should be counted to the length of the GTP packet 457 * that's why szie of gtp1_header should be subtracted, 458 * not size of gtp1_header_long. 459 */ 460 461 len_hdr = sizeof(struct gtp1_header); 462 463 if (msg_type == GTP_ECHO_RSP) { 464 len_pkt = sizeof(struct gtp1u_packet); 465 hdr->length = htons(len_pkt - len_hdr); 466 } else { 467 /* GTP_ECHO_REQ does not carry GTP Information Element, 468 * the why gtp1_header_long is used here. 469 */ 470 len_pkt = sizeof(struct gtp1_header_long); 471 hdr->length = htons(len_pkt - len_hdr); 472 } 473 } 474 475 static int gtp1u_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) 476 { 477 struct gtp1_header_long *gtp1u; 478 struct gtp1u_packet *gtp_pkt; 479 struct rtable *rt; 480 struct flowi4 fl4; 481 struct iphdr *iph; 482 483 gtp1u = (struct gtp1_header_long *)(skb->data + sizeof(struct udphdr)); 484 485 /* 3GPP TS 29.281 5.1 - For the Echo Request, Echo Response, 486 * Error Indication and Supported Extension Headers Notification 487 * messages, the S flag shall be set to 1 and TEID shall be set to 0. 488 */ 489 if (!(gtp1u->flags & GTP1_F_SEQ) || gtp1u->tid) 490 return -1; 491 492 /* pull GTP and UDP headers */ 493 skb_pull_data(skb, 494 sizeof(struct gtp1_header_long) + sizeof(struct udphdr)); 495 496 gtp_pkt = skb_push(skb, sizeof(struct gtp1u_packet)); 497 memset(gtp_pkt, 0, sizeof(struct gtp1u_packet)); 498 499 gtp1u_build_echo_msg(>p_pkt->gtp1u_h, GTP_ECHO_RSP); 500 501 /* 3GPP TS 29.281 7.7.2 - The Restart Counter value in the 502 * Recovery information element shall not be used, i.e. it shall 503 * be set to zero by the sender and shall be ignored by the receiver. 504 * The Recovery information element is mandatory due to backwards 505 * compatibility reasons. 506 */ 507 gtp_pkt->ie.tag = GTPIE_RECOVERY; 508 gtp_pkt->ie.val = 0; 509 510 iph = ip_hdr(skb); 511 512 /* find route to the sender, 513 * src address becomes dst address and vice versa. 514 */ 515 rt = ip4_route_output_gtp(&fl4, gtp->sk1u, iph->saddr, iph->daddr); 516 if (IS_ERR(rt)) { 517 netdev_dbg(gtp->dev, "no route for echo response from %pI4\n", 518 &iph->saddr); 519 return -1; 520 } 521 522 udp_tunnel_xmit_skb(rt, gtp->sk1u, skb, 523 fl4.saddr, fl4.daddr, 524 iph->tos, 525 ip4_dst_hoplimit(&rt->dst), 526 0, 527 htons(GTP1U_PORT), htons(GTP1U_PORT), 528 !net_eq(sock_net(gtp->sk1u), 529 dev_net(gtp->dev)), 530 false); 531 return 0; 532 } 533 534 static int gtp1u_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb) 535 { 536 struct gtp1_header_long *gtp1u; 537 struct echo_info echo; 538 struct sk_buff *msg; 539 struct iphdr *iph; 540 int ret; 541 542 gtp1u = (struct gtp1_header_long *)(skb->data + sizeof(struct udphdr)); 543 544 /* 3GPP TS 29.281 5.1 - For the Echo Request, Echo Response, 545 * Error Indication and Supported Extension Headers Notification 546 * messages, the S flag shall be set to 1 and TEID shall be set to 0. 547 */ 548 if (!(gtp1u->flags & GTP1_F_SEQ) || gtp1u->tid) 549 return -1; 550 551 iph = ip_hdr(skb); 552 echo.ms_addr_ip4.s_addr = iph->daddr; 553 echo.peer_addr_ip4.s_addr = iph->saddr; 554 echo.gtp_version = GTP_V1; 555 556 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); 557 if (!msg) 558 return -ENOMEM; 559 560 ret = gtp_genl_fill_echo(msg, 0, 0, 0, GTP_CMD_ECHOREQ, echo); 561 if (ret < 0) { 562 nlmsg_free(msg); 563 return ret; 564 } 565 566 return genlmsg_multicast_netns(>p_genl_family, dev_net(gtp->dev), 567 msg, 0, GTP_GENL_MCGRP, GFP_ATOMIC); 568 } 569 570 static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) 571 { 572 unsigned int hdrlen = sizeof(struct udphdr) + 573 sizeof(struct gtp1_header); 574 struct gtp1_header *gtp1; 575 struct pdp_ctx *pctx; 576 577 if (!pskb_may_pull(skb, hdrlen)) 578 return -1; 579 580 gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr)); 581 582 if ((gtp1->flags >> 5) != GTP_V1) 583 return 1; 584 585 /* If the sockets were created in kernel, it means that 586 * there is no daemon running in userspace which would 587 * handle echo request. 588 */ 589 if (gtp1->type == GTP_ECHO_REQ && gtp->sk_created) 590 return gtp1u_send_echo_resp(gtp, skb); 591 592 if (gtp1->type == GTP_ECHO_RSP && gtp->sk_created) 593 return gtp1u_handle_echo_resp(gtp, skb); 594 595 if (gtp1->type != GTP_TPDU) 596 return 1; 597 598 /* From 29.060: "This field shall be present if and only if any one or 599 * more of the S, PN and E flags are set.". 600 * 601 * If any of the bit is set, then the remaining ones also have to be 602 * set. 603 */ 604 if (gtp1->flags & GTP1_F_MASK) 605 hdrlen += 4; 606 607 /* Make sure the header is larger enough, including extensions. */ 608 if (!pskb_may_pull(skb, hdrlen)) 609 return -1; 610 611 gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr)); 612 613 pctx = gtp1_pdp_find(gtp, ntohl(gtp1->tid)); 614 if (!pctx) { 615 netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb); 616 return 1; 617 } 618 619 return gtp_rx(pctx, skb, hdrlen, gtp->role); 620 } 621 622 static void __gtp_encap_destroy(struct sock *sk) 623 { 624 struct gtp_dev *gtp; 625 626 lock_sock(sk); 627 gtp = sk->sk_user_data; 628 if (gtp) { 629 if (gtp->sk0 == sk) 630 gtp->sk0 = NULL; 631 else 632 gtp->sk1u = NULL; 633 WRITE_ONCE(udp_sk(sk)->encap_type, 0); 634 rcu_assign_sk_user_data(sk, NULL); 635 release_sock(sk); 636 sock_put(sk); 637 return; 638 } 639 release_sock(sk); 640 } 641 642 static void gtp_encap_destroy(struct sock *sk) 643 { 644 rtnl_lock(); 645 __gtp_encap_destroy(sk); 646 rtnl_unlock(); 647 } 648 649 static void gtp_encap_disable_sock(struct sock *sk) 650 { 651 if (!sk) 652 return; 653 654 __gtp_encap_destroy(sk); 655 } 656 657 static void gtp_encap_disable(struct gtp_dev *gtp) 658 { 659 if (gtp->sk_created) { 660 udp_tunnel_sock_release(gtp->sk0->sk_socket); 661 udp_tunnel_sock_release(gtp->sk1u->sk_socket); 662 gtp->sk_created = false; 663 gtp->sk0 = NULL; 664 gtp->sk1u = NULL; 665 } else { 666 gtp_encap_disable_sock(gtp->sk0); 667 gtp_encap_disable_sock(gtp->sk1u); 668 } 669 } 670 671 /* UDP encapsulation receive handler. See net/ipv4/udp.c. 672 * Return codes: 0: success, <0: error, >0: pass up to userspace UDP socket. 673 */ 674 static int gtp_encap_recv(struct sock *sk, struct sk_buff *skb) 675 { 676 struct gtp_dev *gtp; 677 int ret = 0; 678 679 gtp = rcu_dereference_sk_user_data(sk); 680 if (!gtp) 681 return 1; 682 683 netdev_dbg(gtp->dev, "encap_recv sk=%p\n", sk); 684 685 switch (READ_ONCE(udp_sk(sk)->encap_type)) { 686 case UDP_ENCAP_GTP0: 687 netdev_dbg(gtp->dev, "received GTP0 packet\n"); 688 ret = gtp0_udp_encap_recv(gtp, skb); 689 break; 690 case UDP_ENCAP_GTP1U: 691 netdev_dbg(gtp->dev, "received GTP1U packet\n"); 692 ret = gtp1u_udp_encap_recv(gtp, skb); 693 break; 694 default: 695 ret = -1; /* Shouldn't happen. */ 696 } 697 698 switch (ret) { 699 case 1: 700 netdev_dbg(gtp->dev, "pass up to the process\n"); 701 break; 702 case 0: 703 break; 704 case -1: 705 netdev_dbg(gtp->dev, "GTP packet has been dropped\n"); 706 kfree_skb(skb); 707 ret = 0; 708 break; 709 } 710 711 return ret; 712 } 713 714 static int gtp_dev_init(struct net_device *dev) 715 { 716 struct gtp_dev *gtp = netdev_priv(dev); 717 718 gtp->dev = dev; 719 720 dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats); 721 if (!dev->tstats) 722 return -ENOMEM; 723 724 return 0; 725 } 726 727 static void gtp_dev_uninit(struct net_device *dev) 728 { 729 struct gtp_dev *gtp = netdev_priv(dev); 730 731 gtp_encap_disable(gtp); 732 free_percpu(dev->tstats); 733 } 734 735 static inline void gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx) 736 { 737 int payload_len = skb->len; 738 struct gtp0_header *gtp0; 739 740 gtp0 = skb_push(skb, sizeof(*gtp0)); 741 742 gtp0->flags = 0x1e; /* v0, GTP-non-prime. */ 743 gtp0->type = GTP_TPDU; 744 gtp0->length = htons(payload_len); 745 gtp0->seq = htons((atomic_inc_return(&pctx->tx_seq) - 1) % 0xffff); 746 gtp0->flow = htons(pctx->u.v0.flow); 747 gtp0->number = 0xff; 748 gtp0->spare[0] = gtp0->spare[1] = gtp0->spare[2] = 0xff; 749 gtp0->tid = cpu_to_be64(pctx->u.v0.tid); 750 } 751 752 static inline void gtp1_push_header(struct sk_buff *skb, struct pdp_ctx *pctx) 753 { 754 int payload_len = skb->len; 755 struct gtp1_header *gtp1; 756 757 gtp1 = skb_push(skb, sizeof(*gtp1)); 758 759 /* Bits 8 7 6 5 4 3 2 1 760 * +--+--+--+--+--+--+--+--+ 761 * |version |PT| 0| E| S|PN| 762 * +--+--+--+--+--+--+--+--+ 763 * 0 0 1 1 1 0 0 0 764 */ 765 gtp1->flags = 0x30; /* v1, GTP-non-prime. */ 766 gtp1->type = GTP_TPDU; 767 gtp1->length = htons(payload_len); 768 gtp1->tid = htonl(pctx->u.v1.o_tei); 769 770 /* TODO: Support for extension header, sequence number and N-PDU. 771 * Update the length field if any of them is available. 772 */ 773 } 774 775 struct gtp_pktinfo { 776 struct sock *sk; 777 struct iphdr *iph; 778 struct flowi4 fl4; 779 struct rtable *rt; 780 struct pdp_ctx *pctx; 781 struct net_device *dev; 782 __be16 gtph_port; 783 }; 784 785 static void gtp_push_header(struct sk_buff *skb, struct gtp_pktinfo *pktinfo) 786 { 787 switch (pktinfo->pctx->gtp_version) { 788 case GTP_V0: 789 pktinfo->gtph_port = htons(GTP0_PORT); 790 gtp0_push_header(skb, pktinfo->pctx); 791 break; 792 case GTP_V1: 793 pktinfo->gtph_port = htons(GTP1U_PORT); 794 gtp1_push_header(skb, pktinfo->pctx); 795 break; 796 } 797 } 798 799 static inline void gtp_set_pktinfo_ipv4(struct gtp_pktinfo *pktinfo, 800 struct sock *sk, struct iphdr *iph, 801 struct pdp_ctx *pctx, struct rtable *rt, 802 struct flowi4 *fl4, 803 struct net_device *dev) 804 { 805 pktinfo->sk = sk; 806 pktinfo->iph = iph; 807 pktinfo->pctx = pctx; 808 pktinfo->rt = rt; 809 pktinfo->fl4 = *fl4; 810 pktinfo->dev = dev; 811 } 812 813 static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev, 814 struct gtp_pktinfo *pktinfo) 815 { 816 struct gtp_dev *gtp = netdev_priv(dev); 817 struct pdp_ctx *pctx; 818 struct rtable *rt; 819 struct flowi4 fl4; 820 struct iphdr *iph; 821 __be16 df; 822 int mtu; 823 824 /* Read the IP destination address and resolve the PDP context. 825 * Prepend PDP header with TEI/TID from PDP ctx. 826 */ 827 iph = ip_hdr(skb); 828 if (gtp->role == GTP_ROLE_SGSN) 829 pctx = ipv4_pdp_find(gtp, iph->saddr); 830 else 831 pctx = ipv4_pdp_find(gtp, iph->daddr); 832 833 if (!pctx) { 834 netdev_dbg(dev, "no PDP ctx found for %pI4, skip\n", 835 &iph->daddr); 836 return -ENOENT; 837 } 838 netdev_dbg(dev, "found PDP context %p\n", pctx); 839 840 rt = ip4_route_output_gtp(&fl4, pctx->sk, pctx->peer_addr_ip4.s_addr, 841 inet_sk(pctx->sk)->inet_saddr); 842 if (IS_ERR(rt)) { 843 netdev_dbg(dev, "no route to SSGN %pI4\n", 844 &pctx->peer_addr_ip4.s_addr); 845 dev->stats.tx_carrier_errors++; 846 goto err; 847 } 848 849 if (rt->dst.dev == dev) { 850 netdev_dbg(dev, "circular route to SSGN %pI4\n", 851 &pctx->peer_addr_ip4.s_addr); 852 dev->stats.collisions++; 853 goto err_rt; 854 } 855 856 /* This is similar to tnl_update_pmtu(). */ 857 df = iph->frag_off; 858 if (df) { 859 mtu = dst_mtu(&rt->dst) - dev->hard_header_len - 860 sizeof(struct iphdr) - sizeof(struct udphdr); 861 switch (pctx->gtp_version) { 862 case GTP_V0: 863 mtu -= sizeof(struct gtp0_header); 864 break; 865 case GTP_V1: 866 mtu -= sizeof(struct gtp1_header); 867 break; 868 } 869 } else { 870 mtu = dst_mtu(&rt->dst); 871 } 872 873 skb_dst_update_pmtu_no_confirm(skb, mtu); 874 875 if (iph->frag_off & htons(IP_DF) && 876 ((!skb_is_gso(skb) && skb->len > mtu) || 877 (skb_is_gso(skb) && !skb_gso_validate_network_len(skb, mtu)))) { 878 netdev_dbg(dev, "packet too big, fragmentation needed\n"); 879 icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 880 htonl(mtu)); 881 goto err_rt; 882 } 883 884 gtp_set_pktinfo_ipv4(pktinfo, pctx->sk, iph, pctx, rt, &fl4, dev); 885 gtp_push_header(skb, pktinfo); 886 887 return 0; 888 err_rt: 889 ip_rt_put(rt); 890 err: 891 return -EBADMSG; 892 } 893 894 static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev) 895 { 896 unsigned int proto = ntohs(skb->protocol); 897 struct gtp_pktinfo pktinfo; 898 int err; 899 900 /* Ensure there is sufficient headroom. */ 901 if (skb_cow_head(skb, dev->needed_headroom)) 902 goto tx_err; 903 904 skb_reset_inner_headers(skb); 905 906 /* PDP context lookups in gtp_build_skb_*() need rcu read-side lock. */ 907 rcu_read_lock(); 908 switch (proto) { 909 case ETH_P_IP: 910 err = gtp_build_skb_ip4(skb, dev, &pktinfo); 911 break; 912 default: 913 err = -EOPNOTSUPP; 914 break; 915 } 916 rcu_read_unlock(); 917 918 if (err < 0) 919 goto tx_err; 920 921 switch (proto) { 922 case ETH_P_IP: 923 netdev_dbg(pktinfo.dev, "gtp -> IP src: %pI4 dst: %pI4\n", 924 &pktinfo.iph->saddr, &pktinfo.iph->daddr); 925 udp_tunnel_xmit_skb(pktinfo.rt, pktinfo.sk, skb, 926 pktinfo.fl4.saddr, pktinfo.fl4.daddr, 927 pktinfo.iph->tos, 928 ip4_dst_hoplimit(&pktinfo.rt->dst), 929 0, 930 pktinfo.gtph_port, pktinfo.gtph_port, 931 !net_eq(sock_net(pktinfo.pctx->sk), 932 dev_net(dev)), 933 false); 934 break; 935 } 936 937 return NETDEV_TX_OK; 938 tx_err: 939 dev->stats.tx_errors++; 940 dev_kfree_skb(skb); 941 return NETDEV_TX_OK; 942 } 943 944 static const struct net_device_ops gtp_netdev_ops = { 945 .ndo_init = gtp_dev_init, 946 .ndo_uninit = gtp_dev_uninit, 947 .ndo_start_xmit = gtp_dev_xmit, 948 .ndo_get_stats64 = dev_get_tstats64, 949 }; 950 951 static const struct device_type gtp_type = { 952 .name = "gtp", 953 }; 954 955 static void gtp_link_setup(struct net_device *dev) 956 { 957 unsigned int max_gtp_header_len = sizeof(struct iphdr) + 958 sizeof(struct udphdr) + 959 sizeof(struct gtp0_header); 960 961 dev->netdev_ops = >p_netdev_ops; 962 dev->needs_free_netdev = true; 963 SET_NETDEV_DEVTYPE(dev, >p_type); 964 965 dev->hard_header_len = 0; 966 dev->addr_len = 0; 967 dev->mtu = ETH_DATA_LEN - max_gtp_header_len; 968 969 /* Zero header length. */ 970 dev->type = ARPHRD_NONE; 971 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST; 972 973 dev->priv_flags |= IFF_NO_QUEUE; 974 dev->features |= NETIF_F_LLTX; 975 netif_keep_dst(dev); 976 977 dev->needed_headroom = LL_MAX_HEADER + max_gtp_header_len; 978 } 979 980 static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize); 981 static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]); 982 983 static void gtp_destructor(struct net_device *dev) 984 { 985 struct gtp_dev *gtp = netdev_priv(dev); 986 987 kfree(gtp->addr_hash); 988 kfree(gtp->tid_hash); 989 } 990 991 static struct sock *gtp_create_sock(int type, struct gtp_dev *gtp) 992 { 993 struct udp_tunnel_sock_cfg tuncfg = {}; 994 struct udp_port_cfg udp_conf = { 995 .local_ip.s_addr = htonl(INADDR_ANY), 996 .family = AF_INET, 997 }; 998 struct net *net = gtp->net; 999 struct socket *sock; 1000 int err; 1001 1002 if (type == UDP_ENCAP_GTP0) 1003 udp_conf.local_udp_port = htons(GTP0_PORT); 1004 else if (type == UDP_ENCAP_GTP1U) 1005 udp_conf.local_udp_port = htons(GTP1U_PORT); 1006 else 1007 return ERR_PTR(-EINVAL); 1008 1009 err = udp_sock_create(net, &udp_conf, &sock); 1010 if (err) 1011 return ERR_PTR(err); 1012 1013 tuncfg.sk_user_data = gtp; 1014 tuncfg.encap_type = type; 1015 tuncfg.encap_rcv = gtp_encap_recv; 1016 tuncfg.encap_destroy = NULL; 1017 1018 setup_udp_tunnel_sock(net, sock, &tuncfg); 1019 1020 return sock->sk; 1021 } 1022 1023 static int gtp_create_sockets(struct gtp_dev *gtp, struct nlattr *data[]) 1024 { 1025 struct sock *sk1u = NULL; 1026 struct sock *sk0 = NULL; 1027 1028 sk0 = gtp_create_sock(UDP_ENCAP_GTP0, gtp); 1029 if (IS_ERR(sk0)) 1030 return PTR_ERR(sk0); 1031 1032 sk1u = gtp_create_sock(UDP_ENCAP_GTP1U, gtp); 1033 if (IS_ERR(sk1u)) { 1034 udp_tunnel_sock_release(sk0->sk_socket); 1035 return PTR_ERR(sk1u); 1036 } 1037 1038 gtp->sk_created = true; 1039 gtp->sk0 = sk0; 1040 gtp->sk1u = sk1u; 1041 1042 return 0; 1043 } 1044 1045 static int gtp_newlink(struct net *src_net, struct net_device *dev, 1046 struct nlattr *tb[], struct nlattr *data[], 1047 struct netlink_ext_ack *extack) 1048 { 1049 unsigned int role = GTP_ROLE_GGSN; 1050 struct gtp_dev *gtp; 1051 struct gtp_net *gn; 1052 int hashsize, err; 1053 1054 gtp = netdev_priv(dev); 1055 1056 if (!data[IFLA_GTP_PDP_HASHSIZE]) { 1057 hashsize = 1024; 1058 } else { 1059 hashsize = nla_get_u32(data[IFLA_GTP_PDP_HASHSIZE]); 1060 if (!hashsize) 1061 hashsize = 1024; 1062 } 1063 1064 if (data[IFLA_GTP_ROLE]) { 1065 role = nla_get_u32(data[IFLA_GTP_ROLE]); 1066 if (role > GTP_ROLE_SGSN) 1067 return -EINVAL; 1068 } 1069 gtp->role = role; 1070 1071 if (!data[IFLA_GTP_RESTART_COUNT]) 1072 gtp->restart_count = 0; 1073 else 1074 gtp->restart_count = nla_get_u8(data[IFLA_GTP_RESTART_COUNT]); 1075 1076 gtp->net = src_net; 1077 1078 err = gtp_hashtable_new(gtp, hashsize); 1079 if (err < 0) 1080 return err; 1081 1082 if (data[IFLA_GTP_CREATE_SOCKETS]) 1083 err = gtp_create_sockets(gtp, data); 1084 else 1085 err = gtp_encap_enable(gtp, data); 1086 if (err < 0) 1087 goto out_hashtable; 1088 1089 err = register_netdevice(dev); 1090 if (err < 0) { 1091 netdev_dbg(dev, "failed to register new netdev %d\n", err); 1092 goto out_encap; 1093 } 1094 1095 gn = net_generic(dev_net(dev), gtp_net_id); 1096 list_add_rcu(>p->list, &gn->gtp_dev_list); 1097 dev->priv_destructor = gtp_destructor; 1098 1099 netdev_dbg(dev, "registered new GTP interface\n"); 1100 1101 return 0; 1102 1103 out_encap: 1104 gtp_encap_disable(gtp); 1105 out_hashtable: 1106 kfree(gtp->addr_hash); 1107 kfree(gtp->tid_hash); 1108 return err; 1109 } 1110 1111 static void gtp_dellink(struct net_device *dev, struct list_head *head) 1112 { 1113 struct gtp_dev *gtp = netdev_priv(dev); 1114 struct hlist_node *next; 1115 struct pdp_ctx *pctx; 1116 int i; 1117 1118 for (i = 0; i < gtp->hash_size; i++) 1119 hlist_for_each_entry_safe(pctx, next, >p->tid_hash[i], hlist_tid) 1120 pdp_context_delete(pctx); 1121 1122 list_del_rcu(>p->list); 1123 unregister_netdevice_queue(dev, head); 1124 } 1125 1126 static const struct nla_policy gtp_policy[IFLA_GTP_MAX + 1] = { 1127 [IFLA_GTP_FD0] = { .type = NLA_U32 }, 1128 [IFLA_GTP_FD1] = { .type = NLA_U32 }, 1129 [IFLA_GTP_PDP_HASHSIZE] = { .type = NLA_U32 }, 1130 [IFLA_GTP_ROLE] = { .type = NLA_U32 }, 1131 [IFLA_GTP_CREATE_SOCKETS] = { .type = NLA_U8 }, 1132 [IFLA_GTP_RESTART_COUNT] = { .type = NLA_U8 }, 1133 }; 1134 1135 static int gtp_validate(struct nlattr *tb[], struct nlattr *data[], 1136 struct netlink_ext_ack *extack) 1137 { 1138 if (!data) 1139 return -EINVAL; 1140 1141 return 0; 1142 } 1143 1144 static size_t gtp_get_size(const struct net_device *dev) 1145 { 1146 return nla_total_size(sizeof(__u32)) + /* IFLA_GTP_PDP_HASHSIZE */ 1147 nla_total_size(sizeof(__u32)) + /* IFLA_GTP_ROLE */ 1148 nla_total_size(sizeof(__u8)); /* IFLA_GTP_RESTART_COUNT */ 1149 } 1150 1151 static int gtp_fill_info(struct sk_buff *skb, const struct net_device *dev) 1152 { 1153 struct gtp_dev *gtp = netdev_priv(dev); 1154 1155 if (nla_put_u32(skb, IFLA_GTP_PDP_HASHSIZE, gtp->hash_size)) 1156 goto nla_put_failure; 1157 if (nla_put_u32(skb, IFLA_GTP_ROLE, gtp->role)) 1158 goto nla_put_failure; 1159 if (nla_put_u8(skb, IFLA_GTP_RESTART_COUNT, gtp->restart_count)) 1160 goto nla_put_failure; 1161 1162 return 0; 1163 1164 nla_put_failure: 1165 return -EMSGSIZE; 1166 } 1167 1168 static struct rtnl_link_ops gtp_link_ops __read_mostly = { 1169 .kind = "gtp", 1170 .maxtype = IFLA_GTP_MAX, 1171 .policy = gtp_policy, 1172 .priv_size = sizeof(struct gtp_dev), 1173 .setup = gtp_link_setup, 1174 .validate = gtp_validate, 1175 .newlink = gtp_newlink, 1176 .dellink = gtp_dellink, 1177 .get_size = gtp_get_size, 1178 .fill_info = gtp_fill_info, 1179 }; 1180 1181 static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize) 1182 { 1183 int i; 1184 1185 gtp->addr_hash = kmalloc_array(hsize, sizeof(struct hlist_head), 1186 GFP_KERNEL | __GFP_NOWARN); 1187 if (gtp->addr_hash == NULL) 1188 return -ENOMEM; 1189 1190 gtp->tid_hash = kmalloc_array(hsize, sizeof(struct hlist_head), 1191 GFP_KERNEL | __GFP_NOWARN); 1192 if (gtp->tid_hash == NULL) 1193 goto err1; 1194 1195 gtp->hash_size = hsize; 1196 1197 for (i = 0; i < hsize; i++) { 1198 INIT_HLIST_HEAD(>p->addr_hash[i]); 1199 INIT_HLIST_HEAD(>p->tid_hash[i]); 1200 } 1201 return 0; 1202 err1: 1203 kfree(gtp->addr_hash); 1204 return -ENOMEM; 1205 } 1206 1207 static struct sock *gtp_encap_enable_socket(int fd, int type, 1208 struct gtp_dev *gtp) 1209 { 1210 struct udp_tunnel_sock_cfg tuncfg = {NULL}; 1211 struct socket *sock; 1212 struct sock *sk; 1213 int err; 1214 1215 pr_debug("enable gtp on %d, %d\n", fd, type); 1216 1217 sock = sockfd_lookup(fd, &err); 1218 if (!sock) { 1219 pr_debug("gtp socket fd=%d not found\n", fd); 1220 return NULL; 1221 } 1222 1223 sk = sock->sk; 1224 if (sk->sk_protocol != IPPROTO_UDP || 1225 sk->sk_type != SOCK_DGRAM || 1226 (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)) { 1227 pr_debug("socket fd=%d not UDP\n", fd); 1228 sk = ERR_PTR(-EINVAL); 1229 goto out_sock; 1230 } 1231 1232 lock_sock(sk); 1233 if (sk->sk_user_data) { 1234 sk = ERR_PTR(-EBUSY); 1235 goto out_rel_sock; 1236 } 1237 1238 sock_hold(sk); 1239 1240 tuncfg.sk_user_data = gtp; 1241 tuncfg.encap_type = type; 1242 tuncfg.encap_rcv = gtp_encap_recv; 1243 tuncfg.encap_destroy = gtp_encap_destroy; 1244 1245 setup_udp_tunnel_sock(sock_net(sock->sk), sock, &tuncfg); 1246 1247 out_rel_sock: 1248 release_sock(sock->sk); 1249 out_sock: 1250 sockfd_put(sock); 1251 return sk; 1252 } 1253 1254 static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]) 1255 { 1256 struct sock *sk1u = NULL; 1257 struct sock *sk0 = NULL; 1258 1259 if (!data[IFLA_GTP_FD0] && !data[IFLA_GTP_FD1]) 1260 return -EINVAL; 1261 1262 if (data[IFLA_GTP_FD0]) { 1263 u32 fd0 = nla_get_u32(data[IFLA_GTP_FD0]); 1264 1265 sk0 = gtp_encap_enable_socket(fd0, UDP_ENCAP_GTP0, gtp); 1266 if (IS_ERR(sk0)) 1267 return PTR_ERR(sk0); 1268 } 1269 1270 if (data[IFLA_GTP_FD1]) { 1271 u32 fd1 = nla_get_u32(data[IFLA_GTP_FD1]); 1272 1273 sk1u = gtp_encap_enable_socket(fd1, UDP_ENCAP_GTP1U, gtp); 1274 if (IS_ERR(sk1u)) { 1275 gtp_encap_disable_sock(sk0); 1276 return PTR_ERR(sk1u); 1277 } 1278 } 1279 1280 gtp->sk0 = sk0; 1281 gtp->sk1u = sk1u; 1282 1283 return 0; 1284 } 1285 1286 static struct gtp_dev *gtp_find_dev(struct net *src_net, struct nlattr *nla[]) 1287 { 1288 struct gtp_dev *gtp = NULL; 1289 struct net_device *dev; 1290 struct net *net; 1291 1292 /* Examine the link attributes and figure out which network namespace 1293 * we are talking about. 1294 */ 1295 if (nla[GTPA_NET_NS_FD]) 1296 net = get_net_ns_by_fd(nla_get_u32(nla[GTPA_NET_NS_FD])); 1297 else 1298 net = get_net(src_net); 1299 1300 if (IS_ERR(net)) 1301 return NULL; 1302 1303 /* Check if there's an existing gtpX device to configure */ 1304 dev = dev_get_by_index_rcu(net, nla_get_u32(nla[GTPA_LINK])); 1305 if (dev && dev->netdev_ops == >p_netdev_ops) 1306 gtp = netdev_priv(dev); 1307 1308 put_net(net); 1309 return gtp; 1310 } 1311 1312 static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct genl_info *info) 1313 { 1314 pctx->gtp_version = nla_get_u32(info->attrs[GTPA_VERSION]); 1315 pctx->af = AF_INET; 1316 pctx->peer_addr_ip4.s_addr = 1317 nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]); 1318 pctx->ms_addr_ip4.s_addr = 1319 nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); 1320 1321 switch (pctx->gtp_version) { 1322 case GTP_V0: 1323 /* According to TS 09.60, sections 7.5.1 and 7.5.2, the flow 1324 * label needs to be the same for uplink and downlink packets, 1325 * so let's annotate this. 1326 */ 1327 pctx->u.v0.tid = nla_get_u64(info->attrs[GTPA_TID]); 1328 pctx->u.v0.flow = nla_get_u16(info->attrs[GTPA_FLOW]); 1329 break; 1330 case GTP_V1: 1331 pctx->u.v1.i_tei = nla_get_u32(info->attrs[GTPA_I_TEI]); 1332 pctx->u.v1.o_tei = nla_get_u32(info->attrs[GTPA_O_TEI]); 1333 break; 1334 default: 1335 break; 1336 } 1337 } 1338 1339 static struct pdp_ctx *gtp_pdp_add(struct gtp_dev *gtp, struct sock *sk, 1340 struct genl_info *info) 1341 { 1342 struct pdp_ctx *pctx, *pctx_tid = NULL; 1343 struct net_device *dev = gtp->dev; 1344 u32 hash_ms, hash_tid = 0; 1345 unsigned int version; 1346 bool found = false; 1347 __be32 ms_addr; 1348 1349 ms_addr = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); 1350 hash_ms = ipv4_hashfn(ms_addr) % gtp->hash_size; 1351 version = nla_get_u32(info->attrs[GTPA_VERSION]); 1352 1353 pctx = ipv4_pdp_find(gtp, ms_addr); 1354 if (pctx) 1355 found = true; 1356 if (version == GTP_V0) 1357 pctx_tid = gtp0_pdp_find(gtp, 1358 nla_get_u64(info->attrs[GTPA_TID])); 1359 else if (version == GTP_V1) 1360 pctx_tid = gtp1_pdp_find(gtp, 1361 nla_get_u32(info->attrs[GTPA_I_TEI])); 1362 if (pctx_tid) 1363 found = true; 1364 1365 if (found) { 1366 if (info->nlhdr->nlmsg_flags & NLM_F_EXCL) 1367 return ERR_PTR(-EEXIST); 1368 if (info->nlhdr->nlmsg_flags & NLM_F_REPLACE) 1369 return ERR_PTR(-EOPNOTSUPP); 1370 1371 if (pctx && pctx_tid) 1372 return ERR_PTR(-EEXIST); 1373 if (!pctx) 1374 pctx = pctx_tid; 1375 1376 ipv4_pdp_fill(pctx, info); 1377 1378 if (pctx->gtp_version == GTP_V0) 1379 netdev_dbg(dev, "GTPv0-U: update tunnel id = %llx (pdp %p)\n", 1380 pctx->u.v0.tid, pctx); 1381 else if (pctx->gtp_version == GTP_V1) 1382 netdev_dbg(dev, "GTPv1-U: update tunnel id = %x/%x (pdp %p)\n", 1383 pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx); 1384 1385 return pctx; 1386 1387 } 1388 1389 pctx = kmalloc(sizeof(*pctx), GFP_ATOMIC); 1390 if (pctx == NULL) 1391 return ERR_PTR(-ENOMEM); 1392 1393 sock_hold(sk); 1394 pctx->sk = sk; 1395 pctx->dev = gtp->dev; 1396 ipv4_pdp_fill(pctx, info); 1397 atomic_set(&pctx->tx_seq, 0); 1398 1399 switch (pctx->gtp_version) { 1400 case GTP_V0: 1401 /* TS 09.60: "The flow label identifies unambiguously a GTP 1402 * flow.". We use the tid for this instead, I cannot find a 1403 * situation in which this doesn't unambiguosly identify the 1404 * PDP context. 1405 */ 1406 hash_tid = gtp0_hashfn(pctx->u.v0.tid) % gtp->hash_size; 1407 break; 1408 case GTP_V1: 1409 hash_tid = gtp1u_hashfn(pctx->u.v1.i_tei) % gtp->hash_size; 1410 break; 1411 } 1412 1413 hlist_add_head_rcu(&pctx->hlist_addr, >p->addr_hash[hash_ms]); 1414 hlist_add_head_rcu(&pctx->hlist_tid, >p->tid_hash[hash_tid]); 1415 1416 switch (pctx->gtp_version) { 1417 case GTP_V0: 1418 netdev_dbg(dev, "GTPv0-U: new PDP ctx id=%llx ssgn=%pI4 ms=%pI4 (pdp=%p)\n", 1419 pctx->u.v0.tid, &pctx->peer_addr_ip4, 1420 &pctx->ms_addr_ip4, pctx); 1421 break; 1422 case GTP_V1: 1423 netdev_dbg(dev, "GTPv1-U: new PDP ctx id=%x/%x ssgn=%pI4 ms=%pI4 (pdp=%p)\n", 1424 pctx->u.v1.i_tei, pctx->u.v1.o_tei, 1425 &pctx->peer_addr_ip4, &pctx->ms_addr_ip4, pctx); 1426 break; 1427 } 1428 1429 return pctx; 1430 } 1431 1432 static void pdp_context_free(struct rcu_head *head) 1433 { 1434 struct pdp_ctx *pctx = container_of(head, struct pdp_ctx, rcu_head); 1435 1436 sock_put(pctx->sk); 1437 kfree(pctx); 1438 } 1439 1440 static void pdp_context_delete(struct pdp_ctx *pctx) 1441 { 1442 hlist_del_rcu(&pctx->hlist_tid); 1443 hlist_del_rcu(&pctx->hlist_addr); 1444 call_rcu(&pctx->rcu_head, pdp_context_free); 1445 } 1446 1447 static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation); 1448 1449 static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) 1450 { 1451 unsigned int version; 1452 struct pdp_ctx *pctx; 1453 struct gtp_dev *gtp; 1454 struct sock *sk; 1455 int err; 1456 1457 if (!info->attrs[GTPA_VERSION] || 1458 !info->attrs[GTPA_LINK] || 1459 !info->attrs[GTPA_PEER_ADDRESS] || 1460 !info->attrs[GTPA_MS_ADDRESS]) 1461 return -EINVAL; 1462 1463 version = nla_get_u32(info->attrs[GTPA_VERSION]); 1464 1465 switch (version) { 1466 case GTP_V0: 1467 if (!info->attrs[GTPA_TID] || 1468 !info->attrs[GTPA_FLOW]) 1469 return -EINVAL; 1470 break; 1471 case GTP_V1: 1472 if (!info->attrs[GTPA_I_TEI] || 1473 !info->attrs[GTPA_O_TEI]) 1474 return -EINVAL; 1475 break; 1476 1477 default: 1478 return -EINVAL; 1479 } 1480 1481 rtnl_lock(); 1482 1483 gtp = gtp_find_dev(sock_net(skb->sk), info->attrs); 1484 if (!gtp) { 1485 err = -ENODEV; 1486 goto out_unlock; 1487 } 1488 1489 if (version == GTP_V0) 1490 sk = gtp->sk0; 1491 else if (version == GTP_V1) 1492 sk = gtp->sk1u; 1493 else 1494 sk = NULL; 1495 1496 if (!sk) { 1497 err = -ENODEV; 1498 goto out_unlock; 1499 } 1500 1501 pctx = gtp_pdp_add(gtp, sk, info); 1502 if (IS_ERR(pctx)) { 1503 err = PTR_ERR(pctx); 1504 } else { 1505 gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP, GFP_KERNEL); 1506 err = 0; 1507 } 1508 1509 out_unlock: 1510 rtnl_unlock(); 1511 return err; 1512 } 1513 1514 static struct pdp_ctx *gtp_find_pdp_by_link(struct net *net, 1515 struct nlattr *nla[]) 1516 { 1517 struct gtp_dev *gtp; 1518 1519 gtp = gtp_find_dev(net, nla); 1520 if (!gtp) 1521 return ERR_PTR(-ENODEV); 1522 1523 if (nla[GTPA_MS_ADDRESS]) { 1524 __be32 ip = nla_get_be32(nla[GTPA_MS_ADDRESS]); 1525 1526 return ipv4_pdp_find(gtp, ip); 1527 } else if (nla[GTPA_VERSION]) { 1528 u32 gtp_version = nla_get_u32(nla[GTPA_VERSION]); 1529 1530 if (gtp_version == GTP_V0 && nla[GTPA_TID]) 1531 return gtp0_pdp_find(gtp, nla_get_u64(nla[GTPA_TID])); 1532 else if (gtp_version == GTP_V1 && nla[GTPA_I_TEI]) 1533 return gtp1_pdp_find(gtp, nla_get_u32(nla[GTPA_I_TEI])); 1534 } 1535 1536 return ERR_PTR(-EINVAL); 1537 } 1538 1539 static struct pdp_ctx *gtp_find_pdp(struct net *net, struct nlattr *nla[]) 1540 { 1541 struct pdp_ctx *pctx; 1542 1543 if (nla[GTPA_LINK]) 1544 pctx = gtp_find_pdp_by_link(net, nla); 1545 else 1546 pctx = ERR_PTR(-EINVAL); 1547 1548 if (!pctx) 1549 pctx = ERR_PTR(-ENOENT); 1550 1551 return pctx; 1552 } 1553 1554 static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info) 1555 { 1556 struct pdp_ctx *pctx; 1557 int err = 0; 1558 1559 if (!info->attrs[GTPA_VERSION]) 1560 return -EINVAL; 1561 1562 rcu_read_lock(); 1563 1564 pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs); 1565 if (IS_ERR(pctx)) { 1566 err = PTR_ERR(pctx); 1567 goto out_unlock; 1568 } 1569 1570 if (pctx->gtp_version == GTP_V0) 1571 netdev_dbg(pctx->dev, "GTPv0-U: deleting tunnel id = %llx (pdp %p)\n", 1572 pctx->u.v0.tid, pctx); 1573 else if (pctx->gtp_version == GTP_V1) 1574 netdev_dbg(pctx->dev, "GTPv1-U: deleting tunnel id = %x/%x (pdp %p)\n", 1575 pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx); 1576 1577 gtp_tunnel_notify(pctx, GTP_CMD_DELPDP, GFP_ATOMIC); 1578 pdp_context_delete(pctx); 1579 1580 out_unlock: 1581 rcu_read_unlock(); 1582 return err; 1583 } 1584 1585 static int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq, 1586 int flags, u32 type, struct pdp_ctx *pctx) 1587 { 1588 void *genlh; 1589 1590 genlh = genlmsg_put(skb, snd_portid, snd_seq, >p_genl_family, flags, 1591 type); 1592 if (genlh == NULL) 1593 goto nlmsg_failure; 1594 1595 if (nla_put_u32(skb, GTPA_VERSION, pctx->gtp_version) || 1596 nla_put_u32(skb, GTPA_LINK, pctx->dev->ifindex) || 1597 nla_put_be32(skb, GTPA_PEER_ADDRESS, pctx->peer_addr_ip4.s_addr) || 1598 nla_put_be32(skb, GTPA_MS_ADDRESS, pctx->ms_addr_ip4.s_addr)) 1599 goto nla_put_failure; 1600 1601 switch (pctx->gtp_version) { 1602 case GTP_V0: 1603 if (nla_put_u64_64bit(skb, GTPA_TID, pctx->u.v0.tid, GTPA_PAD) || 1604 nla_put_u16(skb, GTPA_FLOW, pctx->u.v0.flow)) 1605 goto nla_put_failure; 1606 break; 1607 case GTP_V1: 1608 if (nla_put_u32(skb, GTPA_I_TEI, pctx->u.v1.i_tei) || 1609 nla_put_u32(skb, GTPA_O_TEI, pctx->u.v1.o_tei)) 1610 goto nla_put_failure; 1611 break; 1612 } 1613 genlmsg_end(skb, genlh); 1614 return 0; 1615 1616 nlmsg_failure: 1617 nla_put_failure: 1618 genlmsg_cancel(skb, genlh); 1619 return -EMSGSIZE; 1620 } 1621 1622 static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation) 1623 { 1624 struct sk_buff *msg; 1625 int ret; 1626 1627 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, allocation); 1628 if (!msg) 1629 return -ENOMEM; 1630 1631 ret = gtp_genl_fill_info(msg, 0, 0, 0, cmd, pctx); 1632 if (ret < 0) { 1633 nlmsg_free(msg); 1634 return ret; 1635 } 1636 1637 ret = genlmsg_multicast_netns(>p_genl_family, dev_net(pctx->dev), msg, 1638 0, GTP_GENL_MCGRP, GFP_ATOMIC); 1639 return ret; 1640 } 1641 1642 static int gtp_genl_get_pdp(struct sk_buff *skb, struct genl_info *info) 1643 { 1644 struct pdp_ctx *pctx = NULL; 1645 struct sk_buff *skb2; 1646 int err; 1647 1648 if (!info->attrs[GTPA_VERSION]) 1649 return -EINVAL; 1650 1651 rcu_read_lock(); 1652 1653 pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs); 1654 if (IS_ERR(pctx)) { 1655 err = PTR_ERR(pctx); 1656 goto err_unlock; 1657 } 1658 1659 skb2 = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC); 1660 if (skb2 == NULL) { 1661 err = -ENOMEM; 1662 goto err_unlock; 1663 } 1664 1665 err = gtp_genl_fill_info(skb2, NETLINK_CB(skb).portid, info->snd_seq, 1666 0, info->nlhdr->nlmsg_type, pctx); 1667 if (err < 0) 1668 goto err_unlock_free; 1669 1670 rcu_read_unlock(); 1671 return genlmsg_unicast(genl_info_net(info), skb2, info->snd_portid); 1672 1673 err_unlock_free: 1674 kfree_skb(skb2); 1675 err_unlock: 1676 rcu_read_unlock(); 1677 return err; 1678 } 1679 1680 static int gtp_genl_dump_pdp(struct sk_buff *skb, 1681 struct netlink_callback *cb) 1682 { 1683 struct gtp_dev *last_gtp = (struct gtp_dev *)cb->args[2], *gtp; 1684 int i, j, bucket = cb->args[0], skip = cb->args[1]; 1685 struct net *net = sock_net(skb->sk); 1686 struct pdp_ctx *pctx; 1687 struct gtp_net *gn; 1688 1689 gn = net_generic(net, gtp_net_id); 1690 1691 if (cb->args[4]) 1692 return 0; 1693 1694 rcu_read_lock(); 1695 list_for_each_entry_rcu(gtp, &gn->gtp_dev_list, list) { 1696 if (last_gtp && last_gtp != gtp) 1697 continue; 1698 else 1699 last_gtp = NULL; 1700 1701 for (i = bucket; i < gtp->hash_size; i++) { 1702 j = 0; 1703 hlist_for_each_entry_rcu(pctx, >p->tid_hash[i], 1704 hlist_tid) { 1705 if (j >= skip && 1706 gtp_genl_fill_info(skb, 1707 NETLINK_CB(cb->skb).portid, 1708 cb->nlh->nlmsg_seq, 1709 NLM_F_MULTI, 1710 cb->nlh->nlmsg_type, pctx)) { 1711 cb->args[0] = i; 1712 cb->args[1] = j; 1713 cb->args[2] = (unsigned long)gtp; 1714 goto out; 1715 } 1716 j++; 1717 } 1718 skip = 0; 1719 } 1720 bucket = 0; 1721 } 1722 cb->args[4] = 1; 1723 out: 1724 rcu_read_unlock(); 1725 return skb->len; 1726 } 1727 1728 static int gtp_genl_send_echo_req(struct sk_buff *skb, struct genl_info *info) 1729 { 1730 struct sk_buff *skb_to_send; 1731 __be32 src_ip, dst_ip; 1732 unsigned int version; 1733 struct gtp_dev *gtp; 1734 struct flowi4 fl4; 1735 struct rtable *rt; 1736 struct sock *sk; 1737 __be16 port; 1738 int len; 1739 1740 if (!info->attrs[GTPA_VERSION] || 1741 !info->attrs[GTPA_LINK] || 1742 !info->attrs[GTPA_PEER_ADDRESS] || 1743 !info->attrs[GTPA_MS_ADDRESS]) 1744 return -EINVAL; 1745 1746 version = nla_get_u32(info->attrs[GTPA_VERSION]); 1747 dst_ip = nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]); 1748 src_ip = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]); 1749 1750 gtp = gtp_find_dev(sock_net(skb->sk), info->attrs); 1751 if (!gtp) 1752 return -ENODEV; 1753 1754 if (!gtp->sk_created) 1755 return -EOPNOTSUPP; 1756 if (!(gtp->dev->flags & IFF_UP)) 1757 return -ENETDOWN; 1758 1759 if (version == GTP_V0) { 1760 struct gtp0_header *gtp0_h; 1761 1762 len = LL_RESERVED_SPACE(gtp->dev) + sizeof(struct gtp0_header) + 1763 sizeof(struct iphdr) + sizeof(struct udphdr); 1764 1765 skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len); 1766 if (!skb_to_send) 1767 return -ENOMEM; 1768 1769 sk = gtp->sk0; 1770 port = htons(GTP0_PORT); 1771 1772 gtp0_h = skb_push(skb_to_send, sizeof(struct gtp0_header)); 1773 memset(gtp0_h, 0, sizeof(struct gtp0_header)); 1774 gtp0_build_echo_msg(gtp0_h, GTP_ECHO_REQ); 1775 } else if (version == GTP_V1) { 1776 struct gtp1_header_long *gtp1u_h; 1777 1778 len = LL_RESERVED_SPACE(gtp->dev) + 1779 sizeof(struct gtp1_header_long) + 1780 sizeof(struct iphdr) + sizeof(struct udphdr); 1781 1782 skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len); 1783 if (!skb_to_send) 1784 return -ENOMEM; 1785 1786 sk = gtp->sk1u; 1787 port = htons(GTP1U_PORT); 1788 1789 gtp1u_h = skb_push(skb_to_send, 1790 sizeof(struct gtp1_header_long)); 1791 memset(gtp1u_h, 0, sizeof(struct gtp1_header_long)); 1792 gtp1u_build_echo_msg(gtp1u_h, GTP_ECHO_REQ); 1793 } else { 1794 return -ENODEV; 1795 } 1796 1797 rt = ip4_route_output_gtp(&fl4, sk, dst_ip, src_ip); 1798 if (IS_ERR(rt)) { 1799 netdev_dbg(gtp->dev, "no route for echo request to %pI4\n", 1800 &dst_ip); 1801 kfree_skb(skb_to_send); 1802 return -ENODEV; 1803 } 1804 1805 udp_tunnel_xmit_skb(rt, sk, skb_to_send, 1806 fl4.saddr, fl4.daddr, 1807 fl4.flowi4_tos, 1808 ip4_dst_hoplimit(&rt->dst), 1809 0, 1810 port, port, 1811 !net_eq(sock_net(sk), 1812 dev_net(gtp->dev)), 1813 false); 1814 return 0; 1815 } 1816 1817 static const struct nla_policy gtp_genl_policy[GTPA_MAX + 1] = { 1818 [GTPA_LINK] = { .type = NLA_U32, }, 1819 [GTPA_VERSION] = { .type = NLA_U32, }, 1820 [GTPA_TID] = { .type = NLA_U64, }, 1821 [GTPA_PEER_ADDRESS] = { .type = NLA_U32, }, 1822 [GTPA_MS_ADDRESS] = { .type = NLA_U32, }, 1823 [GTPA_FLOW] = { .type = NLA_U16, }, 1824 [GTPA_NET_NS_FD] = { .type = NLA_U32, }, 1825 [GTPA_I_TEI] = { .type = NLA_U32, }, 1826 [GTPA_O_TEI] = { .type = NLA_U32, }, 1827 }; 1828 1829 static const struct genl_small_ops gtp_genl_ops[] = { 1830 { 1831 .cmd = GTP_CMD_NEWPDP, 1832 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1833 .doit = gtp_genl_new_pdp, 1834 .flags = GENL_ADMIN_PERM, 1835 }, 1836 { 1837 .cmd = GTP_CMD_DELPDP, 1838 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1839 .doit = gtp_genl_del_pdp, 1840 .flags = GENL_ADMIN_PERM, 1841 }, 1842 { 1843 .cmd = GTP_CMD_GETPDP, 1844 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1845 .doit = gtp_genl_get_pdp, 1846 .dumpit = gtp_genl_dump_pdp, 1847 .flags = GENL_ADMIN_PERM, 1848 }, 1849 { 1850 .cmd = GTP_CMD_ECHOREQ, 1851 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 1852 .doit = gtp_genl_send_echo_req, 1853 .flags = GENL_ADMIN_PERM, 1854 }, 1855 }; 1856 1857 static struct genl_family gtp_genl_family __ro_after_init = { 1858 .name = "gtp", 1859 .version = 0, 1860 .hdrsize = 0, 1861 .maxattr = GTPA_MAX, 1862 .policy = gtp_genl_policy, 1863 .netnsok = true, 1864 .module = THIS_MODULE, 1865 .small_ops = gtp_genl_ops, 1866 .n_small_ops = ARRAY_SIZE(gtp_genl_ops), 1867 .resv_start_op = GTP_CMD_ECHOREQ + 1, 1868 .mcgrps = gtp_genl_mcgrps, 1869 .n_mcgrps = ARRAY_SIZE(gtp_genl_mcgrps), 1870 }; 1871 1872 static int __net_init gtp_net_init(struct net *net) 1873 { 1874 struct gtp_net *gn = net_generic(net, gtp_net_id); 1875 1876 INIT_LIST_HEAD(&gn->gtp_dev_list); 1877 return 0; 1878 } 1879 1880 static void __net_exit gtp_net_exit(struct net *net) 1881 { 1882 struct gtp_net *gn = net_generic(net, gtp_net_id); 1883 struct gtp_dev *gtp; 1884 LIST_HEAD(list); 1885 1886 rtnl_lock(); 1887 list_for_each_entry(gtp, &gn->gtp_dev_list, list) 1888 gtp_dellink(gtp->dev, &list); 1889 1890 unregister_netdevice_many(&list); 1891 rtnl_unlock(); 1892 } 1893 1894 static struct pernet_operations gtp_net_ops = { 1895 .init = gtp_net_init, 1896 .exit = gtp_net_exit, 1897 .id = >p_net_id, 1898 .size = sizeof(struct gtp_net), 1899 }; 1900 1901 static int __init gtp_init(void) 1902 { 1903 int err; 1904 1905 get_random_bytes(>p_h_initval, sizeof(gtp_h_initval)); 1906 1907 err = register_pernet_subsys(>p_net_ops); 1908 if (err < 0) 1909 goto error_out; 1910 1911 err = rtnl_link_register(>p_link_ops); 1912 if (err < 0) 1913 goto unreg_pernet_subsys; 1914 1915 err = genl_register_family(>p_genl_family); 1916 if (err < 0) 1917 goto unreg_rtnl_link; 1918 1919 pr_info("GTP module loaded (pdp ctx size %zd bytes)\n", 1920 sizeof(struct pdp_ctx)); 1921 return 0; 1922 1923 unreg_rtnl_link: 1924 rtnl_link_unregister(>p_link_ops); 1925 unreg_pernet_subsys: 1926 unregister_pernet_subsys(>p_net_ops); 1927 error_out: 1928 pr_err("error loading GTP module loaded\n"); 1929 return err; 1930 } 1931 late_initcall(gtp_init); 1932 1933 static void __exit gtp_fini(void) 1934 { 1935 genl_unregister_family(>p_genl_family); 1936 rtnl_link_unregister(>p_link_ops); 1937 unregister_pernet_subsys(>p_net_ops); 1938 1939 pr_info("GTP module unloaded\n"); 1940 } 1941 module_exit(gtp_fini); 1942 1943 MODULE_LICENSE("GPL"); 1944 MODULE_AUTHOR("Harald Welte <hwelte@sysmocom.de>"); 1945 MODULE_DESCRIPTION("Interface driver for GTP encapsulated traffic"); 1946 MODULE_ALIAS_RTNL_LINK("gtp"); 1947 MODULE_ALIAS_GENL_FAMILY("gtp"); 1948