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Linux/net/ipv6/datagram.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  *      common UDP/RAW code
  4  *      Linux INET6 implementation
  5  *
  6  *      Authors:
  7  *      Pedro Roque             <roque@di.fc.ul.pt>
  8  */
  9 
 10 #include <linux/capability.h>
 11 #include <linux/errno.h>
 12 #include <linux/types.h>
 13 #include <linux/kernel.h>
 14 #include <linux/interrupt.h>
 15 #include <linux/socket.h>
 16 #include <linux/sockios.h>
 17 #include <linux/in6.h>
 18 #include <linux/ipv6.h>
 19 #include <linux/route.h>
 20 #include <linux/slab.h>
 21 #include <linux/export.h>
 22 
 23 #include <net/ipv6.h>
 24 #include <net/ndisc.h>
 25 #include <net/addrconf.h>
 26 #include <net/transp_v6.h>
 27 #include <net/ip6_route.h>
 28 #include <net/tcp_states.h>
 29 #include <net/dsfield.h>
 30 #include <net/sock_reuseport.h>
 31 
 32 #include <linux/errqueue.h>
 33 #include <linux/uaccess.h>
 34 
 35 static bool ipv6_mapped_addr_any(const struct in6_addr *a)
 36 {
 37         return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
 38 }
 39 
 40 static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
 41 {
 42         struct inet_sock *inet = inet_sk(sk);
 43         struct ipv6_pinfo *np = inet6_sk(sk);
 44 
 45         memset(fl6, 0, sizeof(*fl6));
 46         fl6->flowi6_proto = sk->sk_protocol;
 47         fl6->daddr = sk->sk_v6_daddr;
 48         fl6->saddr = np->saddr;
 49         fl6->flowi6_oif = sk->sk_bound_dev_if;
 50         fl6->flowi6_mark = sk->sk_mark;
 51         fl6->fl6_dport = inet->inet_dport;
 52         fl6->fl6_sport = inet->inet_sport;
 53         fl6->flowlabel = np->flow_label;
 54         fl6->flowi6_uid = sk->sk_uid;
 55 
 56         if (!fl6->flowi6_oif)
 57                 fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
 58 
 59         if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr))
 60                 fl6->flowi6_oif = np->mcast_oif;
 61 
 62         security_sk_classify_flow(sk, flowi6_to_flowi(fl6));
 63 }
 64 
 65 int ip6_datagram_dst_update(struct sock *sk, bool fix_sk_saddr)
 66 {
 67         struct ip6_flowlabel *flowlabel = NULL;
 68         struct in6_addr *final_p, final;
 69         struct ipv6_txoptions *opt;
 70         struct dst_entry *dst;
 71         struct inet_sock *inet = inet_sk(sk);
 72         struct ipv6_pinfo *np = inet6_sk(sk);
 73         struct flowi6 fl6;
 74         int err = 0;
 75 
 76         if (np->sndflow && (np->flow_label & IPV6_FLOWLABEL_MASK)) {
 77                 flowlabel = fl6_sock_lookup(sk, np->flow_label);
 78                 if (IS_ERR(flowlabel))
 79                         return -EINVAL;
 80         }
 81         ip6_datagram_flow_key_init(&fl6, sk);
 82 
 83         rcu_read_lock();
 84         opt = flowlabel ? flowlabel->opt : rcu_dereference(np->opt);
 85         final_p = fl6_update_dst(&fl6, opt, &final);
 86         rcu_read_unlock();
 87 
 88         dst = ip6_dst_lookup_flow(sock_net(sk), sk, &fl6, final_p);
 89         if (IS_ERR(dst)) {
 90                 err = PTR_ERR(dst);
 91                 goto out;
 92         }
 93 
 94         if (fix_sk_saddr) {
 95                 if (ipv6_addr_any(&np->saddr))
 96                         np->saddr = fl6.saddr;
 97 
 98                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
 99                         sk->sk_v6_rcv_saddr = fl6.saddr;
100                         inet->inet_rcv_saddr = LOOPBACK4_IPV6;
101                         if (sk->sk_prot->rehash)
102                                 sk->sk_prot->rehash(sk);
103                 }
104         }
105 
106         ip6_sk_dst_store_flow(sk, dst, &fl6);
107 
108 out:
109         fl6_sock_release(flowlabel);
110         return err;
111 }
112 
113 void ip6_datagram_release_cb(struct sock *sk)
114 {
115         struct dst_entry *dst;
116 
117         if (ipv6_addr_v4mapped(&sk->sk_v6_daddr))
118                 return;
119 
120         rcu_read_lock();
121         dst = __sk_dst_get(sk);
122         if (!dst || !dst->obsolete ||
123             dst->ops->check(dst, inet6_sk(sk)->dst_cookie)) {
124                 rcu_read_unlock();
125                 return;
126         }
127         rcu_read_unlock();
128 
129         ip6_datagram_dst_update(sk, false);
130 }
131 EXPORT_SYMBOL_GPL(ip6_datagram_release_cb);
132 
133 int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr,
134                            int addr_len)
135 {
136         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
137         struct inet_sock        *inet = inet_sk(sk);
138         struct ipv6_pinfo       *np = inet6_sk(sk);
139         struct in6_addr         *daddr, old_daddr;
140         __be32                  fl6_flowlabel = 0;
141         __be32                  old_fl6_flowlabel;
142         __be16                  old_dport;
143         int                     addr_type;
144         int                     err;
145 
146         if (usin->sin6_family == AF_INET) {
147                 if (__ipv6_only_sock(sk))
148                         return -EAFNOSUPPORT;
149                 err = __ip4_datagram_connect(sk, uaddr, addr_len);
150                 goto ipv4_connected;
151         }
152 
153         if (addr_len < SIN6_LEN_RFC2133)
154                 return -EINVAL;
155 
156         if (usin->sin6_family != AF_INET6)
157                 return -EAFNOSUPPORT;
158 
159         if (np->sndflow)
160                 fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
161 
162         if (ipv6_addr_any(&usin->sin6_addr)) {
163                 /*
164                  *      connect to self
165                  */
166                 if (ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
167                         ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
168                                                &usin->sin6_addr);
169                 else
170                         usin->sin6_addr = in6addr_loopback;
171         }
172 
173         addr_type = ipv6_addr_type(&usin->sin6_addr);
174 
175         daddr = &usin->sin6_addr;
176 
177         if (addr_type & IPV6_ADDR_MAPPED) {
178                 struct sockaddr_in sin;
179 
180                 if (__ipv6_only_sock(sk)) {
181                         err = -ENETUNREACH;
182                         goto out;
183                 }
184                 sin.sin_family = AF_INET;
185                 sin.sin_addr.s_addr = daddr->s6_addr32[3];
186                 sin.sin_port = usin->sin6_port;
187 
188                 err = __ip4_datagram_connect(sk,
189                                              (struct sockaddr *) &sin,
190                                              sizeof(sin));
191 
192 ipv4_connected:
193                 if (err)
194                         goto out;
195 
196                 ipv6_addr_set_v4mapped(inet->inet_daddr, &sk->sk_v6_daddr);
197 
198                 if (ipv6_addr_any(&np->saddr) ||
199                     ipv6_mapped_addr_any(&np->saddr))
200                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
201 
202                 if (ipv6_addr_any(&sk->sk_v6_rcv_saddr) ||
203                     ipv6_mapped_addr_any(&sk->sk_v6_rcv_saddr)) {
204                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
205                                                &sk->sk_v6_rcv_saddr);
206                         if (sk->sk_prot->rehash)
207                                 sk->sk_prot->rehash(sk);
208                 }
209 
210                 goto out;
211         }
212 
213         if (__ipv6_addr_needs_scope_id(addr_type)) {
214                 if (addr_len >= sizeof(struct sockaddr_in6) &&
215                     usin->sin6_scope_id) {
216                         if (!sk_dev_equal_l3scope(sk, usin->sin6_scope_id)) {
217                                 err = -EINVAL;
218                                 goto out;
219                         }
220                         sk->sk_bound_dev_if = usin->sin6_scope_id;
221                 }
222 
223                 if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
224                         sk->sk_bound_dev_if = np->mcast_oif;
225 
226                 /* Connect to link-local address requires an interface */
227                 if (!sk->sk_bound_dev_if) {
228                         err = -EINVAL;
229                         goto out;
230                 }
231         }
232 
233         /* save the current peer information before updating it */
234         old_daddr = sk->sk_v6_daddr;
235         old_fl6_flowlabel = np->flow_label;
236         old_dport = inet->inet_dport;
237 
238         sk->sk_v6_daddr = *daddr;
239         np->flow_label = fl6_flowlabel;
240         inet->inet_dport = usin->sin6_port;
241 
242         /*
243          *      Check for a route to destination an obtain the
244          *      destination cache for it.
245          */
246 
247         err = ip6_datagram_dst_update(sk, true);
248         if (err) {
249                 /* Restore the socket peer info, to keep it consistent with
250                  * the old socket state
251                  */
252                 sk->sk_v6_daddr = old_daddr;
253                 np->flow_label = old_fl6_flowlabel;
254                 inet->inet_dport = old_dport;
255                 goto out;
256         }
257 
258         reuseport_has_conns(sk, true);
259         sk->sk_state = TCP_ESTABLISHED;
260         sk_set_txhash(sk);
261 out:
262         return err;
263 }
264 EXPORT_SYMBOL_GPL(__ip6_datagram_connect);
265 
266 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
267 {
268         int res;
269 
270         lock_sock(sk);
271         res = __ip6_datagram_connect(sk, uaddr, addr_len);
272         release_sock(sk);
273         return res;
274 }
275 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
276 
277 int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *uaddr,
278                                  int addr_len)
279 {
280         DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, uaddr);
281         if (sin6->sin6_family != AF_INET6)
282                 return -EAFNOSUPPORT;
283         return ip6_datagram_connect(sk, uaddr, addr_len);
284 }
285 EXPORT_SYMBOL_GPL(ip6_datagram_connect_v6_only);
286 
287 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
288                      __be16 port, u32 info, u8 *payload)
289 {
290         struct ipv6_pinfo *np  = inet6_sk(sk);
291         struct icmp6hdr *icmph = icmp6_hdr(skb);
292         struct sock_exterr_skb *serr;
293 
294         if (!np->recverr)
295                 return;
296 
297         skb = skb_clone(skb, GFP_ATOMIC);
298         if (!skb)
299                 return;
300 
301         skb->protocol = htons(ETH_P_IPV6);
302 
303         serr = SKB_EXT_ERR(skb);
304         serr->ee.ee_errno = err;
305         serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
306         serr->ee.ee_type = icmph->icmp6_type;
307         serr->ee.ee_code = icmph->icmp6_code;
308         serr->ee.ee_pad = 0;
309         serr->ee.ee_info = info;
310         serr->ee.ee_data = 0;
311         serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
312                                   skb_network_header(skb);
313         serr->port = port;
314 
315         __skb_pull(skb, payload - skb->data);
316         skb_reset_transport_header(skb);
317 
318         if (sock_queue_err_skb(sk, skb))
319                 kfree_skb(skb);
320 }
321 
322 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
323 {
324         const struct ipv6_pinfo *np = inet6_sk(sk);
325         struct sock_exterr_skb *serr;
326         struct ipv6hdr *iph;
327         struct sk_buff *skb;
328 
329         if (!np->recverr)
330                 return;
331 
332         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
333         if (!skb)
334                 return;
335 
336         skb->protocol = htons(ETH_P_IPV6);
337 
338         skb_put(skb, sizeof(struct ipv6hdr));
339         skb_reset_network_header(skb);
340         iph = ipv6_hdr(skb);
341         iph->daddr = fl6->daddr;
342         ip6_flow_hdr(iph, 0, 0);
343 
344         serr = SKB_EXT_ERR(skb);
345         serr->ee.ee_errno = err;
346         serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
347         serr->ee.ee_type = 0;
348         serr->ee.ee_code = 0;
349         serr->ee.ee_pad = 0;
350         serr->ee.ee_info = info;
351         serr->ee.ee_data = 0;
352         serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
353         serr->port = fl6->fl6_dport;
354 
355         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
356         skb_reset_transport_header(skb);
357 
358         if (sock_queue_err_skb(sk, skb))
359                 kfree_skb(skb);
360 }
361 
362 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
363 {
364         struct ipv6_pinfo *np = inet6_sk(sk);
365         struct ipv6hdr *iph;
366         struct sk_buff *skb;
367         struct ip6_mtuinfo *mtu_info;
368 
369         if (!np->rxopt.bits.rxpmtu)
370                 return;
371 
372         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
373         if (!skb)
374                 return;
375 
376         skb_put(skb, sizeof(struct ipv6hdr));
377         skb_reset_network_header(skb);
378         iph = ipv6_hdr(skb);
379         iph->daddr = fl6->daddr;
380 
381         mtu_info = IP6CBMTU(skb);
382 
383         mtu_info->ip6m_mtu = mtu;
384         mtu_info->ip6m_addr.sin6_family = AF_INET6;
385         mtu_info->ip6m_addr.sin6_port = 0;
386         mtu_info->ip6m_addr.sin6_flowinfo = 0;
387         mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
388         mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
389 
390         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
391         skb_reset_transport_header(skb);
392 
393         skb = xchg(&np->rxpmtu, skb);
394         kfree_skb(skb);
395 }
396 
397 /* For some errors we have valid addr_offset even with zero payload and
398  * zero port. Also, addr_offset should be supported if port is set.
399  */
400 static inline bool ipv6_datagram_support_addr(struct sock_exterr_skb *serr)
401 {
402         return serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6 ||
403                serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
404                serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL || serr->port;
405 }
406 
407 /* IPv6 supports cmsg on all origins aside from SO_EE_ORIGIN_LOCAL.
408  *
409  * At one point, excluding local errors was a quick test to identify icmp/icmp6
410  * errors. This is no longer true, but the test remained, so the v6 stack,
411  * unlike v4, also honors cmsg requests on all wifi and timestamp errors.
412  */
413 static bool ip6_datagram_support_cmsg(struct sk_buff *skb,
414                                       struct sock_exterr_skb *serr)
415 {
416         if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
417             serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6)
418                 return true;
419 
420         if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL)
421                 return false;
422 
423         if (!IP6CB(skb)->iif)
424                 return false;
425 
426         return true;
427 }
428 
429 /*
430  *      Handle MSG_ERRQUEUE
431  */
432 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
433 {
434         struct ipv6_pinfo *np = inet6_sk(sk);
435         struct sock_exterr_skb *serr;
436         struct sk_buff *skb;
437         DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
438         struct {
439                 struct sock_extended_err ee;
440                 struct sockaddr_in6      offender;
441         } errhdr;
442         int err;
443         int copied;
444 
445         err = -EAGAIN;
446         skb = sock_dequeue_err_skb(sk);
447         if (!skb)
448                 goto out;
449 
450         copied = skb->len;
451         if (copied > len) {
452                 msg->msg_flags |= MSG_TRUNC;
453                 copied = len;
454         }
455         err = skb_copy_datagram_msg(skb, 0, msg, copied);
456         if (unlikely(err)) {
457                 kfree_skb(skb);
458                 return err;
459         }
460         sock_recv_timestamp(msg, sk, skb);
461 
462         serr = SKB_EXT_ERR(skb);
463 
464         if (sin && ipv6_datagram_support_addr(serr)) {
465                 const unsigned char *nh = skb_network_header(skb);
466                 sin->sin6_family = AF_INET6;
467                 sin->sin6_flowinfo = 0;
468                 sin->sin6_port = serr->port;
469                 if (skb->protocol == htons(ETH_P_IPV6)) {
470                         const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),
471                                                                   struct ipv6hdr, daddr);
472                         sin->sin6_addr = ip6h->daddr;
473                         if (np->sndflow)
474                                 sin->sin6_flowinfo = ip6_flowinfo(ip6h);
475                         sin->sin6_scope_id =
476                                 ipv6_iface_scope_id(&sin->sin6_addr,
477                                                     IP6CB(skb)->iif);
478                 } else {
479                         ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
480                                                &sin->sin6_addr);
481                         sin->sin6_scope_id = 0;
482                 }
483                 *addr_len = sizeof(*sin);
484         }
485 
486         memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
487         sin = &errhdr.offender;
488         memset(sin, 0, sizeof(*sin));
489 
490         if (ip6_datagram_support_cmsg(skb, serr)) {
491                 sin->sin6_family = AF_INET6;
492                 if (np->rxopt.all)
493                         ip6_datagram_recv_common_ctl(sk, msg, skb);
494                 if (skb->protocol == htons(ETH_P_IPV6)) {
495                         sin->sin6_addr = ipv6_hdr(skb)->saddr;
496                         if (np->rxopt.all)
497                                 ip6_datagram_recv_specific_ctl(sk, msg, skb);
498                         sin->sin6_scope_id =
499                                 ipv6_iface_scope_id(&sin->sin6_addr,
500                                                     IP6CB(skb)->iif);
501                 } else {
502                         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
503                                                &sin->sin6_addr);
504                         if (inet_sk(sk)->cmsg_flags)
505                                 ip_cmsg_recv(msg, skb);
506                 }
507         }
508 
509         put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
510 
511         /* Now we could try to dump offended packet options */
512 
513         msg->msg_flags |= MSG_ERRQUEUE;
514         err = copied;
515 
516         consume_skb(skb);
517 out:
518         return err;
519 }
520 EXPORT_SYMBOL_GPL(ipv6_recv_error);
521 
522 /*
523  *      Handle IPV6_RECVPATHMTU
524  */
525 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
526                      int *addr_len)
527 {
528         struct ipv6_pinfo *np = inet6_sk(sk);
529         struct sk_buff *skb;
530         struct ip6_mtuinfo mtu_info;
531         DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
532         int err;
533         int copied;
534 
535         err = -EAGAIN;
536         skb = xchg(&np->rxpmtu, NULL);
537         if (!skb)
538                 goto out;
539 
540         copied = skb->len;
541         if (copied > len) {
542                 msg->msg_flags |= MSG_TRUNC;
543                 copied = len;
544         }
545         err = skb_copy_datagram_msg(skb, 0, msg, copied);
546         if (err)
547                 goto out_free_skb;
548 
549         sock_recv_timestamp(msg, sk, skb);
550 
551         memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
552 
553         if (sin) {
554                 sin->sin6_family = AF_INET6;
555                 sin->sin6_flowinfo = 0;
556                 sin->sin6_port = 0;
557                 sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
558                 sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
559                 *addr_len = sizeof(*sin);
560         }
561 
562         put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
563 
564         err = copied;
565 
566 out_free_skb:
567         kfree_skb(skb);
568 out:
569         return err;
570 }
571 
572 
573 void ip6_datagram_recv_common_ctl(struct sock *sk, struct msghdr *msg,
574                                  struct sk_buff *skb)
575 {
576         struct ipv6_pinfo *np = inet6_sk(sk);
577         bool is_ipv6 = skb->protocol == htons(ETH_P_IPV6);
578 
579         if (np->rxopt.bits.rxinfo) {
580                 struct in6_pktinfo src_info;
581 
582                 if (is_ipv6) {
583                         src_info.ipi6_ifindex = IP6CB(skb)->iif;
584                         src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
585                 } else {
586                         src_info.ipi6_ifindex =
587                                 PKTINFO_SKB_CB(skb)->ipi_ifindex;
588                         ipv6_addr_set_v4mapped(ip_hdr(skb)->daddr,
589                                                &src_info.ipi6_addr);
590                 }
591 
592                 if (src_info.ipi6_ifindex >= 0)
593                         put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO,
594                                  sizeof(src_info), &src_info);
595         }
596 }
597 
598 void ip6_datagram_recv_specific_ctl(struct sock *sk, struct msghdr *msg,
599                                     struct sk_buff *skb)
600 {
601         struct ipv6_pinfo *np = inet6_sk(sk);
602         struct inet6_skb_parm *opt = IP6CB(skb);
603         unsigned char *nh = skb_network_header(skb);
604 
605         if (np->rxopt.bits.rxhlim) {
606                 int hlim = ipv6_hdr(skb)->hop_limit;
607                 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
608         }
609 
610         if (np->rxopt.bits.rxtclass) {
611                 int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
612                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
613         }
614 
615         if (np->rxopt.bits.rxflow) {
616                 __be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
617                 if (flowinfo)
618                         put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
619         }
620 
621         /* HbH is allowed only once */
622         if (np->rxopt.bits.hopopts && (opt->flags & IP6SKB_HOPBYHOP)) {
623                 u8 *ptr = nh + sizeof(struct ipv6hdr);
624                 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
625         }
626 
627         if (opt->lastopt &&
628             (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
629                 /*
630                  * Silly enough, but we need to reparse in order to
631                  * report extension headers (except for HbH)
632                  * in order.
633                  *
634                  * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
635                  * (and WILL NOT be) defined because
636                  * IPV6_RECVDSTOPTS is more generic. --yoshfuji
637                  */
638                 unsigned int off = sizeof(struct ipv6hdr);
639                 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
640 
641                 while (off <= opt->lastopt) {
642                         unsigned int len;
643                         u8 *ptr = nh + off;
644 
645                         switch (nexthdr) {
646                         case IPPROTO_DSTOPTS:
647                                 nexthdr = ptr[0];
648                                 len = (ptr[1] + 1) << 3;
649                                 if (np->rxopt.bits.dstopts)
650                                         put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
651                                 break;
652                         case IPPROTO_ROUTING:
653                                 nexthdr = ptr[0];
654                                 len = (ptr[1] + 1) << 3;
655                                 if (np->rxopt.bits.srcrt)
656                                         put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
657                                 break;
658                         case IPPROTO_AH:
659                                 nexthdr = ptr[0];
660                                 len = (ptr[1] + 2) << 2;
661                                 break;
662                         default:
663                                 nexthdr = ptr[0];
664                                 len = (ptr[1] + 1) << 3;
665                                 break;
666                         }
667 
668                         off += len;
669                 }
670         }
671 
672         /* socket options in old style */
673         if (np->rxopt.bits.rxoinfo) {
674                 struct in6_pktinfo src_info;
675 
676                 src_info.ipi6_ifindex = opt->iif;
677                 src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
678                 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
679         }
680         if (np->rxopt.bits.rxohlim) {
681                 int hlim = ipv6_hdr(skb)->hop_limit;
682                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
683         }
684         if (np->rxopt.bits.ohopopts && (opt->flags & IP6SKB_HOPBYHOP)) {
685                 u8 *ptr = nh + sizeof(struct ipv6hdr);
686                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
687         }
688         if (np->rxopt.bits.odstopts && opt->dst0) {
689                 u8 *ptr = nh + opt->dst0;
690                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
691         }
692         if (np->rxopt.bits.osrcrt && opt->srcrt) {
693                 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
694                 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
695         }
696         if (np->rxopt.bits.odstopts && opt->dst1) {
697                 u8 *ptr = nh + opt->dst1;
698                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
699         }
700         if (np->rxopt.bits.rxorigdstaddr) {
701                 struct sockaddr_in6 sin6;
702                 __be16 _ports[2], *ports;
703 
704                 ports = skb_header_pointer(skb, skb_transport_offset(skb),
705                                            sizeof(_ports), &_ports);
706                 if (ports) {
707                         /* All current transport protocols have the port numbers in the
708                          * first four bytes of the transport header and this function is
709                          * written with this assumption in mind.
710                          */
711                         sin6.sin6_family = AF_INET6;
712                         sin6.sin6_addr = ipv6_hdr(skb)->daddr;
713                         sin6.sin6_port = ports[1];
714                         sin6.sin6_flowinfo = 0;
715                         sin6.sin6_scope_id =
716                                 ipv6_iface_scope_id(&ipv6_hdr(skb)->daddr,
717                                                     opt->iif);
718 
719                         put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
720                 }
721         }
722         if (np->rxopt.bits.recvfragsize && opt->frag_max_size) {
723                 int val = opt->frag_max_size;
724 
725                 put_cmsg(msg, SOL_IPV6, IPV6_RECVFRAGSIZE, sizeof(val), &val);
726         }
727 }
728 
729 void ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
730                           struct sk_buff *skb)
731 {
732         ip6_datagram_recv_common_ctl(sk, msg, skb);
733         ip6_datagram_recv_specific_ctl(sk, msg, skb);
734 }
735 EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);
736 
737 int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
738                           struct msghdr *msg, struct flowi6 *fl6,
739                           struct ipcm6_cookie *ipc6)
740 {
741         struct in6_pktinfo *src_info;
742         struct cmsghdr *cmsg;
743         struct ipv6_rt_hdr *rthdr;
744         struct ipv6_opt_hdr *hdr;
745         struct ipv6_txoptions *opt = ipc6->opt;
746         int len;
747         int err = 0;
748 
749         for_each_cmsghdr(cmsg, msg) {
750                 int addr_type;
751 
752                 if (!CMSG_OK(msg, cmsg)) {
753                         err = -EINVAL;
754                         goto exit_f;
755                 }
756 
757                 if (cmsg->cmsg_level == SOL_SOCKET) {
758                         err = __sock_cmsg_send(sk, msg, cmsg, &ipc6->sockc);
759                         if (err)
760                                 return err;
761                         continue;
762                 }
763 
764                 if (cmsg->cmsg_level != SOL_IPV6)
765                         continue;
766 
767                 switch (cmsg->cmsg_type) {
768                 case IPV6_PKTINFO:
769                 case IPV6_2292PKTINFO:
770                     {
771                         struct net_device *dev = NULL;
772                         int src_idx;
773 
774                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
775                                 err = -EINVAL;
776                                 goto exit_f;
777                         }
778 
779                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
780                         src_idx = src_info->ipi6_ifindex;
781 
782                         if (src_idx) {
783                                 if (fl6->flowi6_oif &&
784                                     src_idx != fl6->flowi6_oif &&
785                                     (sk->sk_bound_dev_if != fl6->flowi6_oif ||
786                                      !sk_dev_equal_l3scope(sk, src_idx)))
787                                         return -EINVAL;
788                                 fl6->flowi6_oif = src_idx;
789                         }
790 
791                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
792 
793                         rcu_read_lock();
794                         if (fl6->flowi6_oif) {
795                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
796                                 if (!dev) {
797                                         rcu_read_unlock();
798                                         return -ENODEV;
799                                 }
800                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
801                                 rcu_read_unlock();
802                                 return -EINVAL;
803                         }
804 
805                         if (addr_type != IPV6_ADDR_ANY) {
806                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
807                                 if (!ipv6_can_nonlocal_bind(net, inet_sk(sk)) &&
808                                     !ipv6_chk_addr_and_flags(net, &src_info->ipi6_addr,
809                                                              dev, !strict, 0,
810                                                              IFA_F_TENTATIVE) &&
811                                     !ipv6_chk_acast_addr_src(net, dev,
812                                                              &src_info->ipi6_addr))
813                                         err = -EINVAL;
814                                 else
815                                         fl6->saddr = src_info->ipi6_addr;
816                         }
817 
818                         rcu_read_unlock();
819 
820                         if (err)
821                                 goto exit_f;
822 
823                         break;
824                     }
825 
826                 case IPV6_FLOWINFO:
827                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
828                                 err = -EINVAL;
829                                 goto exit_f;
830                         }
831 
832                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
833                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
834                                         err = -EINVAL;
835                                         goto exit_f;
836                                 }
837                         }
838                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
839                         break;
840 
841                 case IPV6_2292HOPOPTS:
842                 case IPV6_HOPOPTS:
843                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
844                                 err = -EINVAL;
845                                 goto exit_f;
846                         }
847 
848                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
849                         len = ((hdr->hdrlen + 1) << 3);
850                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
851                                 err = -EINVAL;
852                                 goto exit_f;
853                         }
854                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
855                                 err = -EPERM;
856                                 goto exit_f;
857                         }
858                         opt->opt_nflen += len;
859                         opt->hopopt = hdr;
860                         break;
861 
862                 case IPV6_2292DSTOPTS:
863                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
864                                 err = -EINVAL;
865                                 goto exit_f;
866                         }
867 
868                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
869                         len = ((hdr->hdrlen + 1) << 3);
870                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
871                                 err = -EINVAL;
872                                 goto exit_f;
873                         }
874                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
875                                 err = -EPERM;
876                                 goto exit_f;
877                         }
878                         if (opt->dst1opt) {
879                                 err = -EINVAL;
880                                 goto exit_f;
881                         }
882                         opt->opt_flen += len;
883                         opt->dst1opt = hdr;
884                         break;
885 
886                 case IPV6_DSTOPTS:
887                 case IPV6_RTHDRDSTOPTS:
888                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
889                                 err = -EINVAL;
890                                 goto exit_f;
891                         }
892 
893                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
894                         len = ((hdr->hdrlen + 1) << 3);
895                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
896                                 err = -EINVAL;
897                                 goto exit_f;
898                         }
899                         if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
900                                 err = -EPERM;
901                                 goto exit_f;
902                         }
903                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
904                                 opt->opt_flen += len;
905                                 opt->dst1opt = hdr;
906                         } else {
907                                 opt->opt_nflen += len;
908                                 opt->dst0opt = hdr;
909                         }
910                         break;
911 
912                 case IPV6_2292RTHDR:
913                 case IPV6_RTHDR:
914                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
915                                 err = -EINVAL;
916                                 goto exit_f;
917                         }
918 
919                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
920 
921                         switch (rthdr->type) {
922 #if IS_ENABLED(CONFIG_IPV6_MIP6)
923                         case IPV6_SRCRT_TYPE_2:
924                                 if (rthdr->hdrlen != 2 ||
925                                     rthdr->segments_left != 1) {
926                                         err = -EINVAL;
927                                         goto exit_f;
928                                 }
929                                 break;
930 #endif
931                         default:
932                                 err = -EINVAL;
933                                 goto exit_f;
934                         }
935 
936                         len = ((rthdr->hdrlen + 1) << 3);
937 
938                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
939                                 err = -EINVAL;
940                                 goto exit_f;
941                         }
942 
943                         /* segments left must also match */
944                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
945                                 err = -EINVAL;
946                                 goto exit_f;
947                         }
948 
949                         opt->opt_nflen += len;
950                         opt->srcrt = rthdr;
951 
952                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
953                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
954 
955                                 opt->opt_nflen += dsthdrlen;
956                                 opt->dst0opt = opt->dst1opt;
957                                 opt->dst1opt = NULL;
958                                 opt->opt_flen -= dsthdrlen;
959                         }
960 
961                         break;
962 
963                 case IPV6_2292HOPLIMIT:
964                 case IPV6_HOPLIMIT:
965                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
966                                 err = -EINVAL;
967                                 goto exit_f;
968                         }
969 
970                         ipc6->hlimit = *(int *)CMSG_DATA(cmsg);
971                         if (ipc6->hlimit < -1 || ipc6->hlimit > 0xff) {
972                                 err = -EINVAL;
973                                 goto exit_f;
974                         }
975 
976                         break;
977 
978                 case IPV6_TCLASS:
979                     {
980                         int tc;
981 
982                         err = -EINVAL;
983                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
984                                 goto exit_f;
985 
986                         tc = *(int *)CMSG_DATA(cmsg);
987                         if (tc < -1 || tc > 0xff)
988                                 goto exit_f;
989 
990                         err = 0;
991                         ipc6->tclass = tc;
992 
993                         break;
994                     }
995 
996                 case IPV6_DONTFRAG:
997                     {
998                         int df;
999 
1000                         err = -EINVAL;
1001                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
1002                                 goto exit_f;
1003 
1004                         df = *(int *)CMSG_DATA(cmsg);
1005                         if (df < 0 || df > 1)
1006                                 goto exit_f;
1007 
1008                         err = 0;
1009                         ipc6->dontfrag = df;
1010 
1011                         break;
1012                     }
1013                 default:
1014                         net_dbg_ratelimited("invalid cmsg type: %d\n",
1015                                             cmsg->cmsg_type);
1016                         err = -EINVAL;
1017                         goto exit_f;
1018                 }
1019         }
1020 
1021 exit_f:
1022         return err;
1023 }
1024 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
1025 
1026 void __ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
1027                                __u16 srcp, __u16 destp, int rqueue, int bucket)
1028 {
1029         const struct in6_addr *dest, *src;
1030 
1031         dest  = &sp->sk_v6_daddr;
1032         src   = &sp->sk_v6_rcv_saddr;
1033         seq_printf(seq,
1034                    "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
1035                    "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %u\n",
1036                    bucket,
1037                    src->s6_addr32[0], src->s6_addr32[1],
1038                    src->s6_addr32[2], src->s6_addr32[3], srcp,
1039                    dest->s6_addr32[0], dest->s6_addr32[1],
1040                    dest->s6_addr32[2], dest->s6_addr32[3], destp,
1041                    sp->sk_state,
1042                    sk_wmem_alloc_get(sp),
1043                    rqueue,
1044                    0, 0L, 0,
1045                    from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
1046                    0,
1047                    sock_i_ino(sp),
1048                    refcount_read(&sp->sk_refcnt), sp,
1049                    atomic_read(&sp->sk_drops));
1050 }
1051 

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