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