net: relax PKTINFO non local ipv6 udp xmit check
[linux-3.10.git] / net / ipv6 / datagram.c
1 /*
2  *      common UDP/RAW code
3  *      Linux INET6 implementation
4  *
5  *      Authors:
6  *      Pedro Roque             <roque@di.fc.ul.pt>
7  *
8  *      This program is free software; you can redistribute it and/or
9  *      modify it under the terms of the GNU General Public License
10  *      as published by the Free Software Foundation; either version
11  *      2 of the License, or (at your option) any later version.
12  */
13
14 #include <linux/capability.h>
15 #include <linux/errno.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/interrupt.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/in6.h>
22 #include <linux/ipv6.h>
23 #include <linux/route.h>
24 #include <linux/slab.h>
25
26 #include <net/ipv6.h>
27 #include <net/ndisc.h>
28 #include <net/addrconf.h>
29 #include <net/transp_v6.h>
30 #include <net/ip6_route.h>
31 #include <net/tcp_states.h>
32
33 #include <linux/errqueue.h>
34 #include <asm/uaccess.h>
35
36 static inline int ipv6_mapped_addr_any(const struct in6_addr *a)
37 {
38         return (ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0));
39 }
40
41 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
42 {
43         struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
44         struct inet_sock        *inet = inet_sk(sk);
45         struct ipv6_pinfo       *np = inet6_sk(sk);
46         struct in6_addr         *daddr, *final_p, final;
47         struct dst_entry        *dst;
48         struct flowi6           fl6;
49         struct ip6_flowlabel    *flowlabel = NULL;
50         struct ipv6_txoptions   *opt;
51         int                     addr_type;
52         int                     err;
53
54         if (usin->sin6_family == AF_INET) {
55                 if (__ipv6_only_sock(sk))
56                         return -EAFNOSUPPORT;
57                 err = ip4_datagram_connect(sk, uaddr, addr_len);
58                 goto ipv4_connected;
59         }
60
61         if (addr_len < SIN6_LEN_RFC2133)
62                 return -EINVAL;
63
64         if (usin->sin6_family != AF_INET6)
65                 return -EAFNOSUPPORT;
66
67         memset(&fl6, 0, sizeof(fl6));
68         if (np->sndflow) {
69                 fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
70                 if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
71                         flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
72                         if (flowlabel == NULL)
73                                 return -EINVAL;
74                         ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
75                 }
76         }
77
78         addr_type = ipv6_addr_type(&usin->sin6_addr);
79
80         if (addr_type == IPV6_ADDR_ANY) {
81                 /*
82                  *      connect to self
83                  */
84                 usin->sin6_addr.s6_addr[15] = 0x01;
85         }
86
87         daddr = &usin->sin6_addr;
88
89         if (addr_type == IPV6_ADDR_MAPPED) {
90                 struct sockaddr_in sin;
91
92                 if (__ipv6_only_sock(sk)) {
93                         err = -ENETUNREACH;
94                         goto out;
95                 }
96                 sin.sin_family = AF_INET;
97                 sin.sin_addr.s_addr = daddr->s6_addr32[3];
98                 sin.sin_port = usin->sin6_port;
99
100                 err = ip4_datagram_connect(sk,
101                                            (struct sockaddr*) &sin,
102                                            sizeof(sin));
103
104 ipv4_connected:
105                 if (err)
106                         goto out;
107
108                 ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
109
110                 if (ipv6_addr_any(&np->saddr) ||
111                     ipv6_mapped_addr_any(&np->saddr))
112                         ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
113
114                 if (ipv6_addr_any(&np->rcv_saddr) ||
115                     ipv6_mapped_addr_any(&np->rcv_saddr)) {
116                         ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
117                                                &np->rcv_saddr);
118                         if (sk->sk_prot->rehash)
119                                 sk->sk_prot->rehash(sk);
120                 }
121
122                 goto out;
123         }
124
125         if (addr_type&IPV6_ADDR_LINKLOCAL) {
126                 if (addr_len >= sizeof(struct sockaddr_in6) &&
127                     usin->sin6_scope_id) {
128                         if (sk->sk_bound_dev_if &&
129                             sk->sk_bound_dev_if != usin->sin6_scope_id) {
130                                 err = -EINVAL;
131                                 goto out;
132                         }
133                         sk->sk_bound_dev_if = usin->sin6_scope_id;
134                 }
135
136                 if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
137                         sk->sk_bound_dev_if = np->mcast_oif;
138
139                 /* Connect to link-local address requires an interface */
140                 if (!sk->sk_bound_dev_if) {
141                         err = -EINVAL;
142                         goto out;
143                 }
144         }
145
146         ipv6_addr_copy(&np->daddr, daddr);
147         np->flow_label = fl6.flowlabel;
148
149         inet->inet_dport = usin->sin6_port;
150
151         /*
152          *      Check for a route to destination an obtain the
153          *      destination cache for it.
154          */
155
156         fl6.flowi6_proto = sk->sk_protocol;
157         ipv6_addr_copy(&fl6.daddr, &np->daddr);
158         ipv6_addr_copy(&fl6.saddr, &np->saddr);
159         fl6.flowi6_oif = sk->sk_bound_dev_if;
160         fl6.flowi6_mark = sk->sk_mark;
161         fl6.fl6_dport = inet->inet_dport;
162         fl6.fl6_sport = inet->inet_sport;
163
164         if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
165                 fl6.flowi6_oif = np->mcast_oif;
166
167         security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
168
169         opt = flowlabel ? flowlabel->opt : np->opt;
170         final_p = fl6_update_dst(&fl6, opt, &final);
171
172         dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
173         err = 0;
174         if (IS_ERR(dst)) {
175                 err = PTR_ERR(dst);
176                 goto out;
177         }
178
179         /* source address lookup done in ip6_dst_lookup */
180
181         if (ipv6_addr_any(&np->saddr))
182                 ipv6_addr_copy(&np->saddr, &fl6.saddr);
183
184         if (ipv6_addr_any(&np->rcv_saddr)) {
185                 ipv6_addr_copy(&np->rcv_saddr, &fl6.saddr);
186                 inet->inet_rcv_saddr = LOOPBACK4_IPV6;
187                 if (sk->sk_prot->rehash)
188                         sk->sk_prot->rehash(sk);
189         }
190
191         ip6_dst_store(sk, dst,
192                       ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
193                       &np->daddr : NULL,
194 #ifdef CONFIG_IPV6_SUBTREES
195                       ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
196                       &np->saddr :
197 #endif
198                       NULL);
199
200         sk->sk_state = TCP_ESTABLISHED;
201 out:
202         fl6_sock_release(flowlabel);
203         return err;
204 }
205
206 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
207                      __be16 port, u32 info, u8 *payload)
208 {
209         struct ipv6_pinfo *np  = inet6_sk(sk);
210         struct icmp6hdr *icmph = icmp6_hdr(skb);
211         struct sock_exterr_skb *serr;
212
213         if (!np->recverr)
214                 return;
215
216         skb = skb_clone(skb, GFP_ATOMIC);
217         if (!skb)
218                 return;
219
220         skb->protocol = htons(ETH_P_IPV6);
221
222         serr = SKB_EXT_ERR(skb);
223         serr->ee.ee_errno = err;
224         serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
225         serr->ee.ee_type = icmph->icmp6_type;
226         serr->ee.ee_code = icmph->icmp6_code;
227         serr->ee.ee_pad = 0;
228         serr->ee.ee_info = info;
229         serr->ee.ee_data = 0;
230         serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
231                                   skb_network_header(skb);
232         serr->port = port;
233
234         __skb_pull(skb, payload - skb->data);
235         skb_reset_transport_header(skb);
236
237         if (sock_queue_err_skb(sk, skb))
238                 kfree_skb(skb);
239 }
240
241 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
242 {
243         struct ipv6_pinfo *np = inet6_sk(sk);
244         struct sock_exterr_skb *serr;
245         struct ipv6hdr *iph;
246         struct sk_buff *skb;
247
248         if (!np->recverr)
249                 return;
250
251         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
252         if (!skb)
253                 return;
254
255         skb->protocol = htons(ETH_P_IPV6);
256
257         skb_put(skb, sizeof(struct ipv6hdr));
258         skb_reset_network_header(skb);
259         iph = ipv6_hdr(skb);
260         ipv6_addr_copy(&iph->daddr, &fl6->daddr);
261
262         serr = SKB_EXT_ERR(skb);
263         serr->ee.ee_errno = err;
264         serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
265         serr->ee.ee_type = 0;
266         serr->ee.ee_code = 0;
267         serr->ee.ee_pad = 0;
268         serr->ee.ee_info = info;
269         serr->ee.ee_data = 0;
270         serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
271         serr->port = fl6->fl6_dport;
272
273         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
274         skb_reset_transport_header(skb);
275
276         if (sock_queue_err_skb(sk, skb))
277                 kfree_skb(skb);
278 }
279
280 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
281 {
282         struct ipv6_pinfo *np = inet6_sk(sk);
283         struct ipv6hdr *iph;
284         struct sk_buff *skb;
285         struct ip6_mtuinfo *mtu_info;
286
287         if (!np->rxopt.bits.rxpmtu)
288                 return;
289
290         skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
291         if (!skb)
292                 return;
293
294         skb_put(skb, sizeof(struct ipv6hdr));
295         skb_reset_network_header(skb);
296         iph = ipv6_hdr(skb);
297         ipv6_addr_copy(&iph->daddr, &fl6->daddr);
298
299         mtu_info = IP6CBMTU(skb);
300         if (!mtu_info) {
301                 kfree_skb(skb);
302                 return;
303         }
304
305         mtu_info->ip6m_mtu = mtu;
306         mtu_info->ip6m_addr.sin6_family = AF_INET6;
307         mtu_info->ip6m_addr.sin6_port = 0;
308         mtu_info->ip6m_addr.sin6_flowinfo = 0;
309         mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
310         ipv6_addr_copy(&mtu_info->ip6m_addr.sin6_addr, &ipv6_hdr(skb)->daddr);
311
312         __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
313         skb_reset_transport_header(skb);
314
315         skb = xchg(&np->rxpmtu, skb);
316         kfree_skb(skb);
317 }
318
319 /*
320  *      Handle MSG_ERRQUEUE
321  */
322 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
323 {
324         struct ipv6_pinfo *np = inet6_sk(sk);
325         struct sock_exterr_skb *serr;
326         struct sk_buff *skb, *skb2;
327         struct sockaddr_in6 *sin;
328         struct {
329                 struct sock_extended_err ee;
330                 struct sockaddr_in6      offender;
331         } errhdr;
332         int err;
333         int copied;
334
335         err = -EAGAIN;
336         skb = skb_dequeue(&sk->sk_error_queue);
337         if (skb == NULL)
338                 goto out;
339
340         copied = skb->len;
341         if (copied > len) {
342                 msg->msg_flags |= MSG_TRUNC;
343                 copied = len;
344         }
345         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
346         if (err)
347                 goto out_free_skb;
348
349         sock_recv_timestamp(msg, sk, skb);
350
351         serr = SKB_EXT_ERR(skb);
352
353         sin = (struct sockaddr_in6 *)msg->msg_name;
354         if (sin) {
355                 const unsigned char *nh = skb_network_header(skb);
356                 sin->sin6_family = AF_INET6;
357                 sin->sin6_flowinfo = 0;
358                 sin->sin6_port = serr->port;
359                 sin->sin6_scope_id = 0;
360                 if (skb->protocol == htons(ETH_P_IPV6)) {
361                         ipv6_addr_copy(&sin->sin6_addr,
362                                   (struct in6_addr *)(nh + serr->addr_offset));
363                         if (np->sndflow)
364                                 sin->sin6_flowinfo =
365                                         (*(__be32 *)(nh + serr->addr_offset - 24) &
366                                          IPV6_FLOWINFO_MASK);
367                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
368                                 sin->sin6_scope_id = IP6CB(skb)->iif;
369                 } else {
370                         ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
371                                                &sin->sin6_addr);
372                 }
373         }
374
375         memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
376         sin = &errhdr.offender;
377         sin->sin6_family = AF_UNSPEC;
378         if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
379                 sin->sin6_family = AF_INET6;
380                 sin->sin6_flowinfo = 0;
381                 sin->sin6_scope_id = 0;
382                 if (skb->protocol == htons(ETH_P_IPV6)) {
383                         ipv6_addr_copy(&sin->sin6_addr, &ipv6_hdr(skb)->saddr);
384                         if (np->rxopt.all)
385                                 datagram_recv_ctl(sk, msg, skb);
386                         if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
387                                 sin->sin6_scope_id = IP6CB(skb)->iif;
388                 } else {
389                         struct inet_sock *inet = inet_sk(sk);
390
391                         ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
392                                                &sin->sin6_addr);
393                         if (inet->cmsg_flags)
394                                 ip_cmsg_recv(msg, skb);
395                 }
396         }
397
398         put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
399
400         /* Now we could try to dump offended packet options */
401
402         msg->msg_flags |= MSG_ERRQUEUE;
403         err = copied;
404
405         /* Reset and regenerate socket error */
406         spin_lock_bh(&sk->sk_error_queue.lock);
407         sk->sk_err = 0;
408         if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
409                 sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
410                 spin_unlock_bh(&sk->sk_error_queue.lock);
411                 sk->sk_error_report(sk);
412         } else {
413                 spin_unlock_bh(&sk->sk_error_queue.lock);
414         }
415
416 out_free_skb:
417         kfree_skb(skb);
418 out:
419         return err;
420 }
421
422 /*
423  *      Handle IPV6_RECVPATHMTU
424  */
425 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
426 {
427         struct ipv6_pinfo *np = inet6_sk(sk);
428         struct sk_buff *skb;
429         struct sockaddr_in6 *sin;
430         struct ip6_mtuinfo mtu_info;
431         int err;
432         int copied;
433
434         err = -EAGAIN;
435         skb = xchg(&np->rxpmtu, NULL);
436         if (skb == NULL)
437                 goto out;
438
439         copied = skb->len;
440         if (copied > len) {
441                 msg->msg_flags |= MSG_TRUNC;
442                 copied = len;
443         }
444         err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
445         if (err)
446                 goto out_free_skb;
447
448         sock_recv_timestamp(msg, sk, skb);
449
450         memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
451
452         sin = (struct sockaddr_in6 *)msg->msg_name;
453         if (sin) {
454                 sin->sin6_family = AF_INET6;
455                 sin->sin6_flowinfo = 0;
456                 sin->sin6_port = 0;
457                 sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
458                 ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);
459         }
460
461         put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
462
463         err = copied;
464
465 out_free_skb:
466         kfree_skb(skb);
467 out:
468         return err;
469 }
470
471
472 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
473 {
474         struct ipv6_pinfo *np = inet6_sk(sk);
475         struct inet6_skb_parm *opt = IP6CB(skb);
476         unsigned char *nh = skb_network_header(skb);
477
478         if (np->rxopt.bits.rxinfo) {
479                 struct in6_pktinfo src_info;
480
481                 src_info.ipi6_ifindex = opt->iif;
482                 ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
483                 put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
484         }
485
486         if (np->rxopt.bits.rxhlim) {
487                 int hlim = ipv6_hdr(skb)->hop_limit;
488                 put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
489         }
490
491         if (np->rxopt.bits.rxtclass) {
492                 int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
493                 put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
494         }
495
496         if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
497                 __be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
498                 put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
499         }
500
501         /* HbH is allowed only once */
502         if (np->rxopt.bits.hopopts && opt->hop) {
503                 u8 *ptr = nh + opt->hop;
504                 put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
505         }
506
507         if (opt->lastopt &&
508             (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
509                 /*
510                  * Silly enough, but we need to reparse in order to
511                  * report extension headers (except for HbH)
512                  * in order.
513                  *
514                  * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
515                  * (and WILL NOT be) defined because
516                  * IPV6_RECVDSTOPTS is more generic. --yoshfuji
517                  */
518                 unsigned int off = sizeof(struct ipv6hdr);
519                 u8 nexthdr = ipv6_hdr(skb)->nexthdr;
520
521                 while (off <= opt->lastopt) {
522                         unsigned len;
523                         u8 *ptr = nh + off;
524
525                         switch(nexthdr) {
526                         case IPPROTO_DSTOPTS:
527                                 nexthdr = ptr[0];
528                                 len = (ptr[1] + 1) << 3;
529                                 if (np->rxopt.bits.dstopts)
530                                         put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
531                                 break;
532                         case IPPROTO_ROUTING:
533                                 nexthdr = ptr[0];
534                                 len = (ptr[1] + 1) << 3;
535                                 if (np->rxopt.bits.srcrt)
536                                         put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
537                                 break;
538                         case IPPROTO_AH:
539                                 nexthdr = ptr[0];
540                                 len = (ptr[1] + 2) << 2;
541                                 break;
542                         default:
543                                 nexthdr = ptr[0];
544                                 len = (ptr[1] + 1) << 3;
545                                 break;
546                         }
547
548                         off += len;
549                 }
550         }
551
552         /* socket options in old style */
553         if (np->rxopt.bits.rxoinfo) {
554                 struct in6_pktinfo src_info;
555
556                 src_info.ipi6_ifindex = opt->iif;
557                 ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
558                 put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
559         }
560         if (np->rxopt.bits.rxohlim) {
561                 int hlim = ipv6_hdr(skb)->hop_limit;
562                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
563         }
564         if (np->rxopt.bits.ohopopts && opt->hop) {
565                 u8 *ptr = nh + opt->hop;
566                 put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
567         }
568         if (np->rxopt.bits.odstopts && opt->dst0) {
569                 u8 *ptr = nh + opt->dst0;
570                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
571         }
572         if (np->rxopt.bits.osrcrt && opt->srcrt) {
573                 struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
574                 put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
575         }
576         if (np->rxopt.bits.odstopts && opt->dst1) {
577                 u8 *ptr = nh + opt->dst1;
578                 put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
579         }
580         if (np->rxopt.bits.rxorigdstaddr) {
581                 struct sockaddr_in6 sin6;
582                 u16 *ports = (u16 *) skb_transport_header(skb);
583
584                 if (skb_transport_offset(skb) + 4 <= skb->len) {
585                         /* All current transport protocols have the port numbers in the
586                          * first four bytes of the transport header and this function is
587                          * written with this assumption in mind.
588                          */
589
590                         sin6.sin6_family = AF_INET6;
591                         ipv6_addr_copy(&sin6.sin6_addr, &ipv6_hdr(skb)->daddr);
592                         sin6.sin6_port = ports[1];
593                         sin6.sin6_flowinfo = 0;
594                         sin6.sin6_scope_id = 0;
595
596                         put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
597                 }
598         }
599         return 0;
600 }
601
602 int datagram_send_ctl(struct net *net, struct sock *sk,
603                       struct msghdr *msg, struct flowi6 *fl6,
604                       struct ipv6_txoptions *opt,
605                       int *hlimit, int *tclass, int *dontfrag)
606 {
607         struct in6_pktinfo *src_info;
608         struct cmsghdr *cmsg;
609         struct ipv6_rt_hdr *rthdr;
610         struct ipv6_opt_hdr *hdr;
611         int len;
612         int err = 0;
613
614         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
615                 int addr_type;
616
617                 if (!CMSG_OK(msg, cmsg)) {
618                         err = -EINVAL;
619                         goto exit_f;
620                 }
621
622                 if (cmsg->cmsg_level != SOL_IPV6)
623                         continue;
624
625                 switch (cmsg->cmsg_type) {
626                 case IPV6_PKTINFO:
627                 case IPV6_2292PKTINFO:
628                     {
629                         struct net_device *dev = NULL;
630
631                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
632                                 err = -EINVAL;
633                                 goto exit_f;
634                         }
635
636                         src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
637
638                         if (src_info->ipi6_ifindex) {
639                                 if (fl6->flowi6_oif &&
640                                     src_info->ipi6_ifindex != fl6->flowi6_oif)
641                                         return -EINVAL;
642                                 fl6->flowi6_oif = src_info->ipi6_ifindex;
643                         }
644
645                         addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
646
647                         rcu_read_lock();
648                         if (fl6->flowi6_oif) {
649                                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
650                                 if (!dev) {
651                                         rcu_read_unlock();
652                                         return -ENODEV;
653                                 }
654                         } else if (addr_type & IPV6_ADDR_LINKLOCAL) {
655                                 rcu_read_unlock();
656                                 return -EINVAL;
657                         }
658
659                         if (addr_type != IPV6_ADDR_ANY) {
660                                 int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
661                                 if (!inet_sk(sk)->transparent &&
662                                     !ipv6_chk_addr(net, &src_info->ipi6_addr,
663                                                    strict ? dev : NULL, 0))
664                                         err = -EINVAL;
665                                 else
666                                         ipv6_addr_copy(&fl6->saddr, &src_info->ipi6_addr);
667                         }
668
669                         rcu_read_unlock();
670
671                         if (err)
672                                 goto exit_f;
673
674                         break;
675                     }
676
677                 case IPV6_FLOWINFO:
678                         if (cmsg->cmsg_len < CMSG_LEN(4)) {
679                                 err = -EINVAL;
680                                 goto exit_f;
681                         }
682
683                         if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
684                                 if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
685                                         err = -EINVAL;
686                                         goto exit_f;
687                                 }
688                         }
689                         fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
690                         break;
691
692                 case IPV6_2292HOPOPTS:
693                 case IPV6_HOPOPTS:
694                         if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
695                                 err = -EINVAL;
696                                 goto exit_f;
697                         }
698
699                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
700                         len = ((hdr->hdrlen + 1) << 3);
701                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
702                                 err = -EINVAL;
703                                 goto exit_f;
704                         }
705                         if (!capable(CAP_NET_RAW)) {
706                                 err = -EPERM;
707                                 goto exit_f;
708                         }
709                         opt->opt_nflen += len;
710                         opt->hopopt = hdr;
711                         break;
712
713                 case IPV6_2292DSTOPTS:
714                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
715                                 err = -EINVAL;
716                                 goto exit_f;
717                         }
718
719                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
720                         len = ((hdr->hdrlen + 1) << 3);
721                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
722                                 err = -EINVAL;
723                                 goto exit_f;
724                         }
725                         if (!capable(CAP_NET_RAW)) {
726                                 err = -EPERM;
727                                 goto exit_f;
728                         }
729                         if (opt->dst1opt) {
730                                 err = -EINVAL;
731                                 goto exit_f;
732                         }
733                         opt->opt_flen += len;
734                         opt->dst1opt = hdr;
735                         break;
736
737                 case IPV6_DSTOPTS:
738                 case IPV6_RTHDRDSTOPTS:
739                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
740                                 err = -EINVAL;
741                                 goto exit_f;
742                         }
743
744                         hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
745                         len = ((hdr->hdrlen + 1) << 3);
746                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
747                                 err = -EINVAL;
748                                 goto exit_f;
749                         }
750                         if (!capable(CAP_NET_RAW)) {
751                                 err = -EPERM;
752                                 goto exit_f;
753                         }
754                         if (cmsg->cmsg_type == IPV6_DSTOPTS) {
755                                 opt->opt_flen += len;
756                                 opt->dst1opt = hdr;
757                         } else {
758                                 opt->opt_nflen += len;
759                                 opt->dst0opt = hdr;
760                         }
761                         break;
762
763                 case IPV6_2292RTHDR:
764                 case IPV6_RTHDR:
765                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
766                                 err = -EINVAL;
767                                 goto exit_f;
768                         }
769
770                         rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
771
772                         switch (rthdr->type) {
773 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
774                         case IPV6_SRCRT_TYPE_2:
775                                 if (rthdr->hdrlen != 2 ||
776                                     rthdr->segments_left != 1) {
777                                         err = -EINVAL;
778                                         goto exit_f;
779                                 }
780                                 break;
781 #endif
782                         default:
783                                 err = -EINVAL;
784                                 goto exit_f;
785                         }
786
787                         len = ((rthdr->hdrlen + 1) << 3);
788
789                         if (cmsg->cmsg_len < CMSG_LEN(len)) {
790                                 err = -EINVAL;
791                                 goto exit_f;
792                         }
793
794                         /* segments left must also match */
795                         if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
796                                 err = -EINVAL;
797                                 goto exit_f;
798                         }
799
800                         opt->opt_nflen += len;
801                         opt->srcrt = rthdr;
802
803                         if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
804                                 int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
805
806                                 opt->opt_nflen += dsthdrlen;
807                                 opt->dst0opt = opt->dst1opt;
808                                 opt->dst1opt = NULL;
809                                 opt->opt_flen -= dsthdrlen;
810                         }
811
812                         break;
813
814                 case IPV6_2292HOPLIMIT:
815                 case IPV6_HOPLIMIT:
816                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
817                                 err = -EINVAL;
818                                 goto exit_f;
819                         }
820
821                         *hlimit = *(int *)CMSG_DATA(cmsg);
822                         if (*hlimit < -1 || *hlimit > 0xff) {
823                                 err = -EINVAL;
824                                 goto exit_f;
825                         }
826
827                         break;
828
829                 case IPV6_TCLASS:
830                     {
831                         int tc;
832
833                         err = -EINVAL;
834                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
835                                 goto exit_f;
836                         }
837
838                         tc = *(int *)CMSG_DATA(cmsg);
839                         if (tc < -1 || tc > 0xff)
840                                 goto exit_f;
841
842                         err = 0;
843                         *tclass = tc;
844
845                         break;
846                     }
847
848                 case IPV6_DONTFRAG:
849                     {
850                         int df;
851
852                         err = -EINVAL;
853                         if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
854                                 goto exit_f;
855                         }
856
857                         df = *(int *)CMSG_DATA(cmsg);
858                         if (df < 0 || df > 1)
859                                 goto exit_f;
860
861                         err = 0;
862                         *dontfrag = df;
863
864                         break;
865                     }
866                 default:
867                         LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
868                                        cmsg->cmsg_type);
869                         err = -EINVAL;
870                         goto exit_f;
871                 }
872         }
873
874 exit_f:
875         return err;
876 }