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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 = 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 */
263static 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 */
270static 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
295static 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
352static 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
370failure:
371 genlmsg_cancel(skb, genlh);
372 return -EMSGSIZE;
373}
374
375static 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. */
408static 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 */
446static 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
475static 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
534static 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
570static 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
622static 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
642static void gtp_encap_destroy(struct sock *sk)
643{
644 rtnl_lock();
645 __gtp_encap_destroy(sk);
646 rtnl_unlock();
647}
648
649static void gtp_encap_disable_sock(struct sock *sk)
650{
651 if (!sk)
652 return;
653
654 __gtp_encap_destroy(sk);
655}
656
657static 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 */
674static 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
714static 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
727static 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
735static 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
752static 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
775struct 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
785static 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
799static 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
813static 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;
888err_rt:
889 ip_rt_put(rt);
890err:
891 return -EBADMSG;
892}
893
894static 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;
938tx_err:
939 dev->stats.tx_errors++;
940 dev_kfree_skb(skb);
941 return NETDEV_TX_OK;
942}
943
944static 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
951static const struct device_type gtp_type = {
952 .name = "gtp",
953};
954
955static 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
980static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize);
981static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]);
982
983static 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
991static 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
1023static 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
1045static 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
1103out_encap:
1104 gtp_encap_disable(gtp);
1105out_hashtable:
1106 kfree(gtp->addr_hash);
1107 kfree(gtp->tid_hash);
1108 return err;
1109}
1110
1111static void gtp_dellink(struct net_device *dev, struct list_head *head)
1112{
1113 struct gtp_dev *gtp = netdev_priv(dev);
1114 struct pdp_ctx *pctx;
1115 int i;
1116
1117 for (i = 0; i < gtp->hash_size; i++)
1118 hlist_for_each_entry_rcu(pctx, >p->tid_hash[i], hlist_tid)
1119 pdp_context_delete(pctx);
1120
1121 list_del_rcu(>p->list);
1122 unregister_netdevice_queue(dev, head);
1123}
1124
1125static const struct nla_policy gtp_policy[IFLA_GTP_MAX + 1] = {
1126 [IFLA_GTP_FD0] = { .type = NLA_U32 },
1127 [IFLA_GTP_FD1] = { .type = NLA_U32 },
1128 [IFLA_GTP_PDP_HASHSIZE] = { .type = NLA_U32 },
1129 [IFLA_GTP_ROLE] = { .type = NLA_U32 },
1130 [IFLA_GTP_CREATE_SOCKETS] = { .type = NLA_U8 },
1131 [IFLA_GTP_RESTART_COUNT] = { .type = NLA_U8 },
1132};
1133
1134static int gtp_validate(struct nlattr *tb[], struct nlattr *data[],
1135 struct netlink_ext_ack *extack)
1136{
1137 if (!data)
1138 return -EINVAL;
1139
1140 return 0;
1141}
1142
1143static size_t gtp_get_size(const struct net_device *dev)
1144{
1145 return nla_total_size(sizeof(__u32)) + /* IFLA_GTP_PDP_HASHSIZE */
1146 nla_total_size(sizeof(__u32)) + /* IFLA_GTP_ROLE */
1147 nla_total_size(sizeof(__u8)); /* IFLA_GTP_RESTART_COUNT */
1148}
1149
1150static int gtp_fill_info(struct sk_buff *skb, const struct net_device *dev)
1151{
1152 struct gtp_dev *gtp = netdev_priv(dev);
1153
1154 if (nla_put_u32(skb, IFLA_GTP_PDP_HASHSIZE, gtp->hash_size))
1155 goto nla_put_failure;
1156 if (nla_put_u32(skb, IFLA_GTP_ROLE, gtp->role))
1157 goto nla_put_failure;
1158 if (nla_put_u8(skb, IFLA_GTP_RESTART_COUNT, gtp->restart_count))
1159 goto nla_put_failure;
1160
1161 return 0;
1162
1163nla_put_failure:
1164 return -EMSGSIZE;
1165}
1166
1167static struct rtnl_link_ops gtp_link_ops __read_mostly = {
1168 .kind = "gtp",
1169 .maxtype = IFLA_GTP_MAX,
1170 .policy = gtp_policy,
1171 .priv_size = sizeof(struct gtp_dev),
1172 .setup = gtp_link_setup,
1173 .validate = gtp_validate,
1174 .newlink = gtp_newlink,
1175 .dellink = gtp_dellink,
1176 .get_size = gtp_get_size,
1177 .fill_info = gtp_fill_info,
1178};
1179
1180static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize)
1181{
1182 int i;
1183
1184 gtp->addr_hash = kmalloc_array(hsize, sizeof(struct hlist_head),
1185 GFP_KERNEL | __GFP_NOWARN);
1186 if (gtp->addr_hash == NULL)
1187 return -ENOMEM;
1188
1189 gtp->tid_hash = kmalloc_array(hsize, sizeof(struct hlist_head),
1190 GFP_KERNEL | __GFP_NOWARN);
1191 if (gtp->tid_hash == NULL)
1192 goto err1;
1193
1194 gtp->hash_size = hsize;
1195
1196 for (i = 0; i < hsize; i++) {
1197 INIT_HLIST_HEAD(>p->addr_hash[i]);
1198 INIT_HLIST_HEAD(>p->tid_hash[i]);
1199 }
1200 return 0;
1201err1:
1202 kfree(gtp->addr_hash);
1203 return -ENOMEM;
1204}
1205
1206static struct sock *gtp_encap_enable_socket(int fd, int type,
1207 struct gtp_dev *gtp)
1208{
1209 struct udp_tunnel_sock_cfg tuncfg = {NULL};
1210 struct socket *sock;
1211 struct sock *sk;
1212 int err;
1213
1214 pr_debug("enable gtp on %d, %d\n", fd, type);
1215
1216 sock = sockfd_lookup(fd, &err);
1217 if (!sock) {
1218 pr_debug("gtp socket fd=%d not found\n", fd);
1219 return NULL;
1220 }
1221
1222 sk = sock->sk;
1223 if (sk->sk_protocol != IPPROTO_UDP ||
1224 sk->sk_type != SOCK_DGRAM ||
1225 (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)) {
1226 pr_debug("socket fd=%d not UDP\n", fd);
1227 sk = ERR_PTR(-EINVAL);
1228 goto out_sock;
1229 }
1230
1231 lock_sock(sk);
1232 if (sk->sk_user_data) {
1233 sk = ERR_PTR(-EBUSY);
1234 goto out_rel_sock;
1235 }
1236
1237 sock_hold(sk);
1238
1239 tuncfg.sk_user_data = gtp;
1240 tuncfg.encap_type = type;
1241 tuncfg.encap_rcv = gtp_encap_recv;
1242 tuncfg.encap_destroy = gtp_encap_destroy;
1243
1244 setup_udp_tunnel_sock(sock_net(sock->sk), sock, &tuncfg);
1245
1246out_rel_sock:
1247 release_sock(sock->sk);
1248out_sock:
1249 sockfd_put(sock);
1250 return sk;
1251}
1252
1253static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[])
1254{
1255 struct sock *sk1u = NULL;
1256 struct sock *sk0 = NULL;
1257
1258 if (!data[IFLA_GTP_FD0] && !data[IFLA_GTP_FD1])
1259 return -EINVAL;
1260
1261 if (data[IFLA_GTP_FD0]) {
1262 u32 fd0 = nla_get_u32(data[IFLA_GTP_FD0]);
1263
1264 sk0 = gtp_encap_enable_socket(fd0, UDP_ENCAP_GTP0, gtp);
1265 if (IS_ERR(sk0))
1266 return PTR_ERR(sk0);
1267 }
1268
1269 if (data[IFLA_GTP_FD1]) {
1270 u32 fd1 = nla_get_u32(data[IFLA_GTP_FD1]);
1271
1272 sk1u = gtp_encap_enable_socket(fd1, UDP_ENCAP_GTP1U, gtp);
1273 if (IS_ERR(sk1u)) {
1274 gtp_encap_disable_sock(sk0);
1275 return PTR_ERR(sk1u);
1276 }
1277 }
1278
1279 gtp->sk0 = sk0;
1280 gtp->sk1u = sk1u;
1281
1282 return 0;
1283}
1284
1285static struct gtp_dev *gtp_find_dev(struct net *src_net, struct nlattr *nla[])
1286{
1287 struct gtp_dev *gtp = NULL;
1288 struct net_device *dev;
1289 struct net *net;
1290
1291 /* Examine the link attributes and figure out which network namespace
1292 * we are talking about.
1293 */
1294 if (nla[GTPA_NET_NS_FD])
1295 net = get_net_ns_by_fd(nla_get_u32(nla[GTPA_NET_NS_FD]));
1296 else
1297 net = get_net(src_net);
1298
1299 if (IS_ERR(net))
1300 return NULL;
1301
1302 /* Check if there's an existing gtpX device to configure */
1303 dev = dev_get_by_index_rcu(net, nla_get_u32(nla[GTPA_LINK]));
1304 if (dev && dev->netdev_ops == >p_netdev_ops)
1305 gtp = netdev_priv(dev);
1306
1307 put_net(net);
1308 return gtp;
1309}
1310
1311static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct genl_info *info)
1312{
1313 pctx->gtp_version = nla_get_u32(info->attrs[GTPA_VERSION]);
1314 pctx->af = AF_INET;
1315 pctx->peer_addr_ip4.s_addr =
1316 nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]);
1317 pctx->ms_addr_ip4.s_addr =
1318 nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
1319
1320 switch (pctx->gtp_version) {
1321 case GTP_V0:
1322 /* According to TS 09.60, sections 7.5.1 and 7.5.2, the flow
1323 * label needs to be the same for uplink and downlink packets,
1324 * so let's annotate this.
1325 */
1326 pctx->u.v0.tid = nla_get_u64(info->attrs[GTPA_TID]);
1327 pctx->u.v0.flow = nla_get_u16(info->attrs[GTPA_FLOW]);
1328 break;
1329 case GTP_V1:
1330 pctx->u.v1.i_tei = nla_get_u32(info->attrs[GTPA_I_TEI]);
1331 pctx->u.v1.o_tei = nla_get_u32(info->attrs[GTPA_O_TEI]);
1332 break;
1333 default:
1334 break;
1335 }
1336}
1337
1338static struct pdp_ctx *gtp_pdp_add(struct gtp_dev *gtp, struct sock *sk,
1339 struct genl_info *info)
1340{
1341 struct pdp_ctx *pctx, *pctx_tid = NULL;
1342 struct net_device *dev = gtp->dev;
1343 u32 hash_ms, hash_tid = 0;
1344 unsigned int version;
1345 bool found = false;
1346 __be32 ms_addr;
1347
1348 ms_addr = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
1349 hash_ms = ipv4_hashfn(ms_addr) % gtp->hash_size;
1350 version = nla_get_u32(info->attrs[GTPA_VERSION]);
1351
1352 pctx = ipv4_pdp_find(gtp, ms_addr);
1353 if (pctx)
1354 found = true;
1355 if (version == GTP_V0)
1356 pctx_tid = gtp0_pdp_find(gtp,
1357 nla_get_u64(info->attrs[GTPA_TID]));
1358 else if (version == GTP_V1)
1359 pctx_tid = gtp1_pdp_find(gtp,
1360 nla_get_u32(info->attrs[GTPA_I_TEI]));
1361 if (pctx_tid)
1362 found = true;
1363
1364 if (found) {
1365 if (info->nlhdr->nlmsg_flags & NLM_F_EXCL)
1366 return ERR_PTR(-EEXIST);
1367 if (info->nlhdr->nlmsg_flags & NLM_F_REPLACE)
1368 return ERR_PTR(-EOPNOTSUPP);
1369
1370 if (pctx && pctx_tid)
1371 return ERR_PTR(-EEXIST);
1372 if (!pctx)
1373 pctx = pctx_tid;
1374
1375 ipv4_pdp_fill(pctx, info);
1376
1377 if (pctx->gtp_version == GTP_V0)
1378 netdev_dbg(dev, "GTPv0-U: update tunnel id = %llx (pdp %p)\n",
1379 pctx->u.v0.tid, pctx);
1380 else if (pctx->gtp_version == GTP_V1)
1381 netdev_dbg(dev, "GTPv1-U: update tunnel id = %x/%x (pdp %p)\n",
1382 pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx);
1383
1384 return pctx;
1385
1386 }
1387
1388 pctx = kmalloc(sizeof(*pctx), GFP_ATOMIC);
1389 if (pctx == NULL)
1390 return ERR_PTR(-ENOMEM);
1391
1392 sock_hold(sk);
1393 pctx->sk = sk;
1394 pctx->dev = gtp->dev;
1395 ipv4_pdp_fill(pctx, info);
1396 atomic_set(&pctx->tx_seq, 0);
1397
1398 switch (pctx->gtp_version) {
1399 case GTP_V0:
1400 /* TS 09.60: "The flow label identifies unambiguously a GTP
1401 * flow.". We use the tid for this instead, I cannot find a
1402 * situation in which this doesn't unambiguosly identify the
1403 * PDP context.
1404 */
1405 hash_tid = gtp0_hashfn(pctx->u.v0.tid) % gtp->hash_size;
1406 break;
1407 case GTP_V1:
1408 hash_tid = gtp1u_hashfn(pctx->u.v1.i_tei) % gtp->hash_size;
1409 break;
1410 }
1411
1412 hlist_add_head_rcu(&pctx->hlist_addr, >p->addr_hash[hash_ms]);
1413 hlist_add_head_rcu(&pctx->hlist_tid, >p->tid_hash[hash_tid]);
1414
1415 switch (pctx->gtp_version) {
1416 case GTP_V0:
1417 netdev_dbg(dev, "GTPv0-U: new PDP ctx id=%llx ssgn=%pI4 ms=%pI4 (pdp=%p)\n",
1418 pctx->u.v0.tid, &pctx->peer_addr_ip4,
1419 &pctx->ms_addr_ip4, pctx);
1420 break;
1421 case GTP_V1:
1422 netdev_dbg(dev, "GTPv1-U: new PDP ctx id=%x/%x ssgn=%pI4 ms=%pI4 (pdp=%p)\n",
1423 pctx->u.v1.i_tei, pctx->u.v1.o_tei,
1424 &pctx->peer_addr_ip4, &pctx->ms_addr_ip4, pctx);
1425 break;
1426 }
1427
1428 return pctx;
1429}
1430
1431static void pdp_context_free(struct rcu_head *head)
1432{
1433 struct pdp_ctx *pctx = container_of(head, struct pdp_ctx, rcu_head);
1434
1435 sock_put(pctx->sk);
1436 kfree(pctx);
1437}
1438
1439static void pdp_context_delete(struct pdp_ctx *pctx)
1440{
1441 hlist_del_rcu(&pctx->hlist_tid);
1442 hlist_del_rcu(&pctx->hlist_addr);
1443 call_rcu(&pctx->rcu_head, pdp_context_free);
1444}
1445
1446static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation);
1447
1448static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info)
1449{
1450 unsigned int version;
1451 struct pdp_ctx *pctx;
1452 struct gtp_dev *gtp;
1453 struct sock *sk;
1454 int err;
1455
1456 if (!info->attrs[GTPA_VERSION] ||
1457 !info->attrs[GTPA_LINK] ||
1458 !info->attrs[GTPA_PEER_ADDRESS] ||
1459 !info->attrs[GTPA_MS_ADDRESS])
1460 return -EINVAL;
1461
1462 version = nla_get_u32(info->attrs[GTPA_VERSION]);
1463
1464 switch (version) {
1465 case GTP_V0:
1466 if (!info->attrs[GTPA_TID] ||
1467 !info->attrs[GTPA_FLOW])
1468 return -EINVAL;
1469 break;
1470 case GTP_V1:
1471 if (!info->attrs[GTPA_I_TEI] ||
1472 !info->attrs[GTPA_O_TEI])
1473 return -EINVAL;
1474 break;
1475
1476 default:
1477 return -EINVAL;
1478 }
1479
1480 rtnl_lock();
1481
1482 gtp = gtp_find_dev(sock_net(skb->sk), info->attrs);
1483 if (!gtp) {
1484 err = -ENODEV;
1485 goto out_unlock;
1486 }
1487
1488 if (version == GTP_V0)
1489 sk = gtp->sk0;
1490 else if (version == GTP_V1)
1491 sk = gtp->sk1u;
1492 else
1493 sk = NULL;
1494
1495 if (!sk) {
1496 err = -ENODEV;
1497 goto out_unlock;
1498 }
1499
1500 pctx = gtp_pdp_add(gtp, sk, info);
1501 if (IS_ERR(pctx)) {
1502 err = PTR_ERR(pctx);
1503 } else {
1504 gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP, GFP_KERNEL);
1505 err = 0;
1506 }
1507
1508out_unlock:
1509 rtnl_unlock();
1510 return err;
1511}
1512
1513static struct pdp_ctx *gtp_find_pdp_by_link(struct net *net,
1514 struct nlattr *nla[])
1515{
1516 struct gtp_dev *gtp;
1517
1518 gtp = gtp_find_dev(net, nla);
1519 if (!gtp)
1520 return ERR_PTR(-ENODEV);
1521
1522 if (nla[GTPA_MS_ADDRESS]) {
1523 __be32 ip = nla_get_be32(nla[GTPA_MS_ADDRESS]);
1524
1525 return ipv4_pdp_find(gtp, ip);
1526 } else if (nla[GTPA_VERSION]) {
1527 u32 gtp_version = nla_get_u32(nla[GTPA_VERSION]);
1528
1529 if (gtp_version == GTP_V0 && nla[GTPA_TID])
1530 return gtp0_pdp_find(gtp, nla_get_u64(nla[GTPA_TID]));
1531 else if (gtp_version == GTP_V1 && nla[GTPA_I_TEI])
1532 return gtp1_pdp_find(gtp, nla_get_u32(nla[GTPA_I_TEI]));
1533 }
1534
1535 return ERR_PTR(-EINVAL);
1536}
1537
1538static struct pdp_ctx *gtp_find_pdp(struct net *net, struct nlattr *nla[])
1539{
1540 struct pdp_ctx *pctx;
1541
1542 if (nla[GTPA_LINK])
1543 pctx = gtp_find_pdp_by_link(net, nla);
1544 else
1545 pctx = ERR_PTR(-EINVAL);
1546
1547 if (!pctx)
1548 pctx = ERR_PTR(-ENOENT);
1549
1550 return pctx;
1551}
1552
1553static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info)
1554{
1555 struct pdp_ctx *pctx;
1556 int err = 0;
1557
1558 if (!info->attrs[GTPA_VERSION])
1559 return -EINVAL;
1560
1561 rcu_read_lock();
1562
1563 pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs);
1564 if (IS_ERR(pctx)) {
1565 err = PTR_ERR(pctx);
1566 goto out_unlock;
1567 }
1568
1569 if (pctx->gtp_version == GTP_V0)
1570 netdev_dbg(pctx->dev, "GTPv0-U: deleting tunnel id = %llx (pdp %p)\n",
1571 pctx->u.v0.tid, pctx);
1572 else if (pctx->gtp_version == GTP_V1)
1573 netdev_dbg(pctx->dev, "GTPv1-U: deleting tunnel id = %x/%x (pdp %p)\n",
1574 pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx);
1575
1576 gtp_tunnel_notify(pctx, GTP_CMD_DELPDP, GFP_ATOMIC);
1577 pdp_context_delete(pctx);
1578
1579out_unlock:
1580 rcu_read_unlock();
1581 return err;
1582}
1583
1584static int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq,
1585 int flags, u32 type, struct pdp_ctx *pctx)
1586{
1587 void *genlh;
1588
1589 genlh = genlmsg_put(skb, snd_portid, snd_seq, >p_genl_family, flags,
1590 type);
1591 if (genlh == NULL)
1592 goto nlmsg_failure;
1593
1594 if (nla_put_u32(skb, GTPA_VERSION, pctx->gtp_version) ||
1595 nla_put_u32(skb, GTPA_LINK, pctx->dev->ifindex) ||
1596 nla_put_be32(skb, GTPA_PEER_ADDRESS, pctx->peer_addr_ip4.s_addr) ||
1597 nla_put_be32(skb, GTPA_MS_ADDRESS, pctx->ms_addr_ip4.s_addr))
1598 goto nla_put_failure;
1599
1600 switch (pctx->gtp_version) {
1601 case GTP_V0:
1602 if (nla_put_u64_64bit(skb, GTPA_TID, pctx->u.v0.tid, GTPA_PAD) ||
1603 nla_put_u16(skb, GTPA_FLOW, pctx->u.v0.flow))
1604 goto nla_put_failure;
1605 break;
1606 case GTP_V1:
1607 if (nla_put_u32(skb, GTPA_I_TEI, pctx->u.v1.i_tei) ||
1608 nla_put_u32(skb, GTPA_O_TEI, pctx->u.v1.o_tei))
1609 goto nla_put_failure;
1610 break;
1611 }
1612 genlmsg_end(skb, genlh);
1613 return 0;
1614
1615nlmsg_failure:
1616nla_put_failure:
1617 genlmsg_cancel(skb, genlh);
1618 return -EMSGSIZE;
1619}
1620
1621static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation)
1622{
1623 struct sk_buff *msg;
1624 int ret;
1625
1626 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, allocation);
1627 if (!msg)
1628 return -ENOMEM;
1629
1630 ret = gtp_genl_fill_info(msg, 0, 0, 0, cmd, pctx);
1631 if (ret < 0) {
1632 nlmsg_free(msg);
1633 return ret;
1634 }
1635
1636 ret = genlmsg_multicast_netns(>p_genl_family, dev_net(pctx->dev), msg,
1637 0, GTP_GENL_MCGRP, GFP_ATOMIC);
1638 return ret;
1639}
1640
1641static int gtp_genl_get_pdp(struct sk_buff *skb, struct genl_info *info)
1642{
1643 struct pdp_ctx *pctx = NULL;
1644 struct sk_buff *skb2;
1645 int err;
1646
1647 if (!info->attrs[GTPA_VERSION])
1648 return -EINVAL;
1649
1650 rcu_read_lock();
1651
1652 pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs);
1653 if (IS_ERR(pctx)) {
1654 err = PTR_ERR(pctx);
1655 goto err_unlock;
1656 }
1657
1658 skb2 = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
1659 if (skb2 == NULL) {
1660 err = -ENOMEM;
1661 goto err_unlock;
1662 }
1663
1664 err = gtp_genl_fill_info(skb2, NETLINK_CB(skb).portid, info->snd_seq,
1665 0, info->nlhdr->nlmsg_type, pctx);
1666 if (err < 0)
1667 goto err_unlock_free;
1668
1669 rcu_read_unlock();
1670 return genlmsg_unicast(genl_info_net(info), skb2, info->snd_portid);
1671
1672err_unlock_free:
1673 kfree_skb(skb2);
1674err_unlock:
1675 rcu_read_unlock();
1676 return err;
1677}
1678
1679static int gtp_genl_dump_pdp(struct sk_buff *skb,
1680 struct netlink_callback *cb)
1681{
1682 struct gtp_dev *last_gtp = (struct gtp_dev *)cb->args[2], *gtp;
1683 int i, j, bucket = cb->args[0], skip = cb->args[1];
1684 struct net *net = sock_net(skb->sk);
1685 struct pdp_ctx *pctx;
1686 struct gtp_net *gn;
1687
1688 gn = net_generic(net, gtp_net_id);
1689
1690 if (cb->args[4])
1691 return 0;
1692
1693 rcu_read_lock();
1694 list_for_each_entry_rcu(gtp, &gn->gtp_dev_list, list) {
1695 if (last_gtp && last_gtp != gtp)
1696 continue;
1697 else
1698 last_gtp = NULL;
1699
1700 for (i = bucket; i < gtp->hash_size; i++) {
1701 j = 0;
1702 hlist_for_each_entry_rcu(pctx, >p->tid_hash[i],
1703 hlist_tid) {
1704 if (j >= skip &&
1705 gtp_genl_fill_info(skb,
1706 NETLINK_CB(cb->skb).portid,
1707 cb->nlh->nlmsg_seq,
1708 NLM_F_MULTI,
1709 cb->nlh->nlmsg_type, pctx)) {
1710 cb->args[0] = i;
1711 cb->args[1] = j;
1712 cb->args[2] = (unsigned long)gtp;
1713 goto out;
1714 }
1715 j++;
1716 }
1717 skip = 0;
1718 }
1719 bucket = 0;
1720 }
1721 cb->args[4] = 1;
1722out:
1723 rcu_read_unlock();
1724 return skb->len;
1725}
1726
1727static int gtp_genl_send_echo_req(struct sk_buff *skb, struct genl_info *info)
1728{
1729 struct sk_buff *skb_to_send;
1730 __be32 src_ip, dst_ip;
1731 unsigned int version;
1732 struct gtp_dev *gtp;
1733 struct flowi4 fl4;
1734 struct rtable *rt;
1735 struct sock *sk;
1736 __be16 port;
1737 int len;
1738
1739 if (!info->attrs[GTPA_VERSION] ||
1740 !info->attrs[GTPA_LINK] ||
1741 !info->attrs[GTPA_PEER_ADDRESS] ||
1742 !info->attrs[GTPA_MS_ADDRESS])
1743 return -EINVAL;
1744
1745 version = nla_get_u32(info->attrs[GTPA_VERSION]);
1746 dst_ip = nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]);
1747 src_ip = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
1748
1749 gtp = gtp_find_dev(sock_net(skb->sk), info->attrs);
1750 if (!gtp)
1751 return -ENODEV;
1752
1753 if (!gtp->sk_created)
1754 return -EOPNOTSUPP;
1755 if (!(gtp->dev->flags & IFF_UP))
1756 return -ENETDOWN;
1757
1758 if (version == GTP_V0) {
1759 struct gtp0_header *gtp0_h;
1760
1761 len = LL_RESERVED_SPACE(gtp->dev) + sizeof(struct gtp0_header) +
1762 sizeof(struct iphdr) + sizeof(struct udphdr);
1763
1764 skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len);
1765 if (!skb_to_send)
1766 return -ENOMEM;
1767
1768 sk = gtp->sk0;
1769 port = htons(GTP0_PORT);
1770
1771 gtp0_h = skb_push(skb_to_send, sizeof(struct gtp0_header));
1772 memset(gtp0_h, 0, sizeof(struct gtp0_header));
1773 gtp0_build_echo_msg(gtp0_h, GTP_ECHO_REQ);
1774 } else if (version == GTP_V1) {
1775 struct gtp1_header_long *gtp1u_h;
1776
1777 len = LL_RESERVED_SPACE(gtp->dev) +
1778 sizeof(struct gtp1_header_long) +
1779 sizeof(struct iphdr) + sizeof(struct udphdr);
1780
1781 skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len);
1782 if (!skb_to_send)
1783 return -ENOMEM;
1784
1785 sk = gtp->sk1u;
1786 port = htons(GTP1U_PORT);
1787
1788 gtp1u_h = skb_push(skb_to_send,
1789 sizeof(struct gtp1_header_long));
1790 memset(gtp1u_h, 0, sizeof(struct gtp1_header_long));
1791 gtp1u_build_echo_msg(gtp1u_h, GTP_ECHO_REQ);
1792 } else {
1793 return -ENODEV;
1794 }
1795
1796 rt = ip4_route_output_gtp(&fl4, sk, dst_ip, src_ip);
1797 if (IS_ERR(rt)) {
1798 netdev_dbg(gtp->dev, "no route for echo request to %pI4\n",
1799 &dst_ip);
1800 kfree_skb(skb_to_send);
1801 return -ENODEV;
1802 }
1803
1804 udp_tunnel_xmit_skb(rt, sk, skb_to_send,
1805 fl4.saddr, fl4.daddr,
1806 fl4.flowi4_tos,
1807 ip4_dst_hoplimit(&rt->dst),
1808 0,
1809 port, port,
1810 !net_eq(sock_net(sk),
1811 dev_net(gtp->dev)),
1812 false);
1813 return 0;
1814}
1815
1816static const struct nla_policy gtp_genl_policy[GTPA_MAX + 1] = {
1817 [GTPA_LINK] = { .type = NLA_U32, },
1818 [GTPA_VERSION] = { .type = NLA_U32, },
1819 [GTPA_TID] = { .type = NLA_U64, },
1820 [GTPA_PEER_ADDRESS] = { .type = NLA_U32, },
1821 [GTPA_MS_ADDRESS] = { .type = NLA_U32, },
1822 [GTPA_FLOW] = { .type = NLA_U16, },
1823 [GTPA_NET_NS_FD] = { .type = NLA_U32, },
1824 [GTPA_I_TEI] = { .type = NLA_U32, },
1825 [GTPA_O_TEI] = { .type = NLA_U32, },
1826};
1827
1828static const struct genl_small_ops gtp_genl_ops[] = {
1829 {
1830 .cmd = GTP_CMD_NEWPDP,
1831 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1832 .doit = gtp_genl_new_pdp,
1833 .flags = GENL_ADMIN_PERM,
1834 },
1835 {
1836 .cmd = GTP_CMD_DELPDP,
1837 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1838 .doit = gtp_genl_del_pdp,
1839 .flags = GENL_ADMIN_PERM,
1840 },
1841 {
1842 .cmd = GTP_CMD_GETPDP,
1843 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1844 .doit = gtp_genl_get_pdp,
1845 .dumpit = gtp_genl_dump_pdp,
1846 .flags = GENL_ADMIN_PERM,
1847 },
1848 {
1849 .cmd = GTP_CMD_ECHOREQ,
1850 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1851 .doit = gtp_genl_send_echo_req,
1852 .flags = GENL_ADMIN_PERM,
1853 },
1854};
1855
1856static struct genl_family gtp_genl_family __ro_after_init = {
1857 .name = "gtp",
1858 .version = 0,
1859 .hdrsize = 0,
1860 .maxattr = GTPA_MAX,
1861 .policy = gtp_genl_policy,
1862 .netnsok = true,
1863 .module = THIS_MODULE,
1864 .small_ops = gtp_genl_ops,
1865 .n_small_ops = ARRAY_SIZE(gtp_genl_ops),
1866 .resv_start_op = GTP_CMD_ECHOREQ + 1,
1867 .mcgrps = gtp_genl_mcgrps,
1868 .n_mcgrps = ARRAY_SIZE(gtp_genl_mcgrps),
1869};
1870
1871static int __net_init gtp_net_init(struct net *net)
1872{
1873 struct gtp_net *gn = net_generic(net, gtp_net_id);
1874
1875 INIT_LIST_HEAD(&gn->gtp_dev_list);
1876 return 0;
1877}
1878
1879static void __net_exit gtp_net_exit(struct net *net)
1880{
1881 struct gtp_net *gn = net_generic(net, gtp_net_id);
1882 struct gtp_dev *gtp;
1883 LIST_HEAD(list);
1884
1885 rtnl_lock();
1886 list_for_each_entry(gtp, &gn->gtp_dev_list, list)
1887 gtp_dellink(gtp->dev, &list);
1888
1889 unregister_netdevice_many(&list);
1890 rtnl_unlock();
1891}
1892
1893static struct pernet_operations gtp_net_ops = {
1894 .init = gtp_net_init,
1895 .exit = gtp_net_exit,
1896 .id = >p_net_id,
1897 .size = sizeof(struct gtp_net),
1898};
1899
1900static int __init gtp_init(void)
1901{
1902 int err;
1903
1904 get_random_bytes(>p_h_initval, sizeof(gtp_h_initval));
1905
1906 err = register_pernet_subsys(>p_net_ops);
1907 if (err < 0)
1908 goto error_out;
1909
1910 err = rtnl_link_register(>p_link_ops);
1911 if (err < 0)
1912 goto unreg_pernet_subsys;
1913
1914 err = genl_register_family(>p_genl_family);
1915 if (err < 0)
1916 goto unreg_rtnl_link;
1917
1918 pr_info("GTP module loaded (pdp ctx size %zd bytes)\n",
1919 sizeof(struct pdp_ctx));
1920 return 0;
1921
1922unreg_rtnl_link:
1923 rtnl_link_unregister(>p_link_ops);
1924unreg_pernet_subsys:
1925 unregister_pernet_subsys(>p_net_ops);
1926error_out:
1927 pr_err("error loading GTP module loaded\n");
1928 return err;
1929}
1930late_initcall(gtp_init);
1931
1932static void __exit gtp_fini(void)
1933{
1934 genl_unregister_family(>p_genl_family);
1935 rtnl_link_unregister(>p_link_ops);
1936 unregister_pernet_subsys(>p_net_ops);
1937
1938 pr_info("GTP module unloaded\n");
1939}
1940module_exit(gtp_fini);
1941
1942MODULE_LICENSE("GPL");
1943MODULE_AUTHOR("Harald Welte <hwelte@sysmocom.de>");
1944MODULE_DESCRIPTION("Interface driver for GTP encapsulated traffic");
1945MODULE_ALIAS_RTNL_LINK("gtp");
1946MODULE_ALIAS_GENL_FAMILY("gtp");