]> git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/blob - net/ipv6/ip6_output.c
projects / mirror_ubuntu-focal-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
[IPSEC] xfrm: Abstract out encapsulation modes
[mirror_ubuntu-focal-kernel.git] / net / ipv6 / ip6_output.c
1 /*
2 * IPv6 output functions
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * $Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $
9 *
10 * Based on linux/net/ipv4/ip_output.c
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * Changes:
18 * A.N.Kuznetsov : airthmetics in fragmentation.
19 * extension headers are implemented.
20 * route changes now work.
21 * ip6_forward does not confuse sniffers.
22 * etc.
23 *
24 * H. von Brand : Added missing #include <linux/string.h>
25 * Imran Patel : frag id should be in NBO
26 * Kazunori MIYAZAWA @USAGI
27 * : add ip6_append_data and related functions
28 * for datagram xmit
29 */
30
31 #include <linux/config.h>
32 #include <linux/errno.h>
33 #include <linux/types.h>
34 #include <linux/string.h>
35 #include <linux/socket.h>
36 #include <linux/net.h>
37 #include <linux/netdevice.h>
38 #include <linux/if_arp.h>
39 #include <linux/in6.h>
40 #include <linux/tcp.h>
41 #include <linux/route.h>
42 #include <linux/module.h>
43
44 #include <linux/netfilter.h>
45 #include <linux/netfilter_ipv6.h>
46
47 #include <net/sock.h>
48 #include <net/snmp.h>
49
50 #include <net/ipv6.h>
51 #include <net/ndisc.h>
52 #include <net/protocol.h>
53 #include <net/ip6_route.h>
54 #include <net/addrconf.h>
55 #include <net/rawv6.h>
56 #include <net/icmp.h>
57 #include <net/xfrm.h>
58 #include <net/checksum.h>
59
60 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
61
62 static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr)
63 {
64 static u32 ipv6_fragmentation_id = 1;
65 static DEFINE_SPINLOCK(ip6_id_lock);
66
67 spin_lock_bh(&ip6_id_lock);
68 fhdr->identification = htonl(ipv6_fragmentation_id);
69 if (++ipv6_fragmentation_id == 0)
70 ipv6_fragmentation_id = 1;
71 spin_unlock_bh(&ip6_id_lock);
72 }
73
74 static inline int ip6_output_finish(struct sk_buff *skb)
75 {
76
77 struct dst_entry *dst = skb->dst;
78 struct hh_cache *hh = dst->hh;
79
80 if (hh) {
81 int hh_alen;
82
83 read_lock_bh(&hh->hh_lock);
84 hh_alen = HH_DATA_ALIGN(hh->hh_len);
85 memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
86 read_unlock_bh(&hh->hh_lock);
87 skb_push(skb, hh->hh_len);
88 return hh->hh_output(skb);
89 } else if (dst->neighbour)
90 return dst->neighbour->output(skb);
91
92 IP6_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
93 kfree_skb(skb);
94 return -EINVAL;
95
96 }
97
98 /* dev_loopback_xmit for use with netfilter. */
99 static int ip6_dev_loopback_xmit(struct sk_buff *newskb)
100 {
101 newskb->mac.raw = newskb->data;
102 __skb_pull(newskb, newskb->nh.raw - newskb->data);
103 newskb->pkt_type = PACKET_LOOPBACK;
104 newskb->ip_summed = CHECKSUM_UNNECESSARY;
105 BUG_TRAP(newskb->dst);
106
107 netif_rx(newskb);
108 return 0;
109 }
110
111
112 static int ip6_output2(struct sk_buff *skb)
113 {
114 struct dst_entry *dst = skb->dst;
115 struct net_device *dev = dst->dev;
116
117 skb->protocol = htons(ETH_P_IPV6);
118 skb->dev = dev;
119
120 if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr)) {
121 struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL;
122
123 if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) &&
124 ipv6_chk_mcast_addr(dev, &skb->nh.ipv6h->daddr,
125 &skb->nh.ipv6h->saddr)) {
126 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
127
128 /* Do not check for IFF_ALLMULTI; multicast routing
129 is not supported in any case.
130 */
131 if (newskb)
132 NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL,
133 newskb->dev,
134 ip6_dev_loopback_xmit);
135
136 if (skb->nh.ipv6h->hop_limit == 0) {
137 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
138 kfree_skb(skb);
139 return 0;
140 }
141 }
142
143 IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
144 }
145
146 return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish);
147 }
148
149 int ip6_output(struct sk_buff *skb)
150 {
151 if ((skb->len > dst_mtu(skb->dst) && !skb_shinfo(skb)->ufo_size) ||
152 dst_allfrag(skb->dst))
153 return ip6_fragment(skb, ip6_output2);
154 else
155 return ip6_output2(skb);
156 }
157
158 /*
159 * xmit an sk_buff (used by TCP)
160 */
161
162 int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
163 struct ipv6_txoptions *opt, int ipfragok)
164 {
165 struct ipv6_pinfo *np = inet6_sk(sk);
166 struct in6_addr *first_hop = &fl->fl6_dst;
167 struct dst_entry *dst = skb->dst;
168 struct ipv6hdr *hdr;
169 u8 proto = fl->proto;
170 int seg_len = skb->len;
171 int hlimit, tclass;
172 u32 mtu;
173
174 if (opt) {
175 int head_room;
176
177 /* First: exthdrs may take lots of space (~8K for now)
178 MAX_HEADER is not enough.
179 */
180 head_room = opt->opt_nflen + opt->opt_flen;
181 seg_len += head_room;
182 head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
183
184 if (skb_headroom(skb) < head_room) {
185 struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room);
186 kfree_skb(skb);
187 skb = skb2;
188 if (skb == NULL) {
189 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
190 return -ENOBUFS;
191 }
192 if (sk)
193 skb_set_owner_w(skb, sk);
194 }
195 if (opt->opt_flen)
196 ipv6_push_frag_opts(skb, opt, &proto);
197 if (opt->opt_nflen)
198 ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop);
199 }
200
201 hdr = skb->nh.ipv6h = (struct ipv6hdr*)skb_push(skb, sizeof(struct ipv6hdr));
202
203 /*
204 * Fill in the IPv6 header
205 */
206
207 hlimit = -1;
208 if (np)
209 hlimit = np->hop_limit;
210 if (hlimit < 0)
211 hlimit = dst_metric(dst, RTAX_HOPLIMIT);
212 if (hlimit < 0)
213 hlimit = ipv6_get_hoplimit(dst->dev);
214
215 tclass = -1;
216 if (np)
217 tclass = np->tclass;
218 if (tclass < 0)
219 tclass = 0;
220
221 *(u32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel;
222
223 hdr->payload_len = htons(seg_len);
224 hdr->nexthdr = proto;
225 hdr->hop_limit = hlimit;
226
227 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
228 ipv6_addr_copy(&hdr->daddr, first_hop);
229
230 skb->priority = sk->sk_priority;
231
232 mtu = dst_mtu(dst);
233 if ((skb->len <= mtu) || ipfragok) {
234 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
235 return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev,
236 dst_output);
237 }
238
239 if (net_ratelimit())
240 printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n");
241 skb->dev = dst->dev;
242 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
243 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
244 kfree_skb(skb);
245 return -EMSGSIZE;
246 }
247
248 /*
249 * To avoid extra problems ND packets are send through this
250 * routine. It's code duplication but I really want to avoid
251 * extra checks since ipv6_build_header is used by TCP (which
252 * is for us performance critical)
253 */
254
255 int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev,
256 struct in6_addr *saddr, struct in6_addr *daddr,
257 int proto, int len)
258 {
259 struct ipv6_pinfo *np = inet6_sk(sk);
260 struct ipv6hdr *hdr;
261 int totlen;
262
263 skb->protocol = htons(ETH_P_IPV6);
264 skb->dev = dev;
265
266 totlen = len + sizeof(struct ipv6hdr);
267
268 hdr = (struct ipv6hdr *) skb_put(skb, sizeof(struct ipv6hdr));
269 skb->nh.ipv6h = hdr;
270
271 *(u32*)hdr = htonl(0x60000000);
272
273 hdr->payload_len = htons(len);
274 hdr->nexthdr = proto;
275 hdr->hop_limit = np->hop_limit;
276
277 ipv6_addr_copy(&hdr->saddr, saddr);
278 ipv6_addr_copy(&hdr->daddr, daddr);
279
280 return 0;
281 }
282
283 static int ip6_call_ra_chain(struct sk_buff *skb, int sel)
284 {
285 struct ip6_ra_chain *ra;
286 struct sock *last = NULL;
287
288 read_lock(&ip6_ra_lock);
289 for (ra = ip6_ra_chain; ra; ra = ra->next) {
290 struct sock *sk = ra->sk;
291 if (sk && ra->sel == sel &&
292 (!sk->sk_bound_dev_if ||
293 sk->sk_bound_dev_if == skb->dev->ifindex)) {
294 if (last) {
295 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
296 if (skb2)
297 rawv6_rcv(last, skb2);
298 }
299 last = sk;
300 }
301 }
302
303 if (last) {
304 rawv6_rcv(last, skb);
305 read_unlock(&ip6_ra_lock);
306 return 1;
307 }
308 read_unlock(&ip6_ra_lock);
309 return 0;
310 }
311
312 static inline int ip6_forward_finish(struct sk_buff *skb)
313 {
314 return dst_output(skb);
315 }
316
317 int ip6_forward(struct sk_buff *skb)
318 {
319 struct dst_entry *dst = skb->dst;
320 struct ipv6hdr *hdr = skb->nh.ipv6h;
321 struct inet6_skb_parm *opt = IP6CB(skb);
322
323 if (ipv6_devconf.forwarding == 0)
324 goto error;
325
326 if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
327 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS);
328 goto drop;
329 }
330
331 skb->ip_summed = CHECKSUM_NONE;
332
333 /*
334 * We DO NOT make any processing on
335 * RA packets, pushing them to user level AS IS
336 * without ane WARRANTY that application will be able
337 * to interpret them. The reason is that we
338 * cannot make anything clever here.
339 *
340 * We are not end-node, so that if packet contains
341 * AH/ESP, we cannot make anything.
342 * Defragmentation also would be mistake, RA packets
343 * cannot be fragmented, because there is no warranty
344 * that different fragments will go along one path. --ANK
345 */
346 if (opt->ra) {
347 u8 *ptr = skb->nh.raw + opt->ra;
348 if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
349 return 0;
350 }
351
352 /*
353 * check and decrement ttl
354 */
355 if (hdr->hop_limit <= 1) {
356 /* Force OUTPUT device used as source address */
357 skb->dev = dst->dev;
358 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
359 0, skb->dev);
360
361 kfree_skb(skb);
362 return -ETIMEDOUT;
363 }
364
365 if (!xfrm6_route_forward(skb)) {
366 IP6_INC_STATS(IPSTATS_MIB_INDISCARDS);
367 goto drop;
368 }
369 dst = skb->dst;
370
371 /* IPv6 specs say nothing about it, but it is clear that we cannot
372 send redirects to source routed frames.
373 */
374 if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) {
375 struct in6_addr *target = NULL;
376 struct rt6_info *rt;
377 struct neighbour *n = dst->neighbour;
378
379 /*
380 * incoming and outgoing devices are the same
381 * send a redirect.
382 */
383
384 rt = (struct rt6_info *) dst;
385 if ((rt->rt6i_flags & RTF_GATEWAY))
386 target = (struct in6_addr*)&n->primary_key;
387 else
388 target = &hdr->daddr;
389
390 /* Limit redirects both by destination (here)
391 and by source (inside ndisc_send_redirect)
392 */
393 if (xrlim_allow(dst, 1*HZ))
394 ndisc_send_redirect(skb, n, target);
395 } else if (ipv6_addr_type(&hdr->saddr)&(IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK
396 |IPV6_ADDR_LINKLOCAL)) {
397 /* This check is security critical. */
398 goto error;
399 }
400
401 if (skb->len > dst_mtu(dst)) {
402 /* Again, force OUTPUT device used as source address */
403 skb->dev = dst->dev;
404 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev);
405 IP6_INC_STATS_BH(IPSTATS_MIB_INTOOBIGERRORS);
406 IP6_INC_STATS_BH(IPSTATS_MIB_FRAGFAILS);
407 kfree_skb(skb);
408 return -EMSGSIZE;
409 }
410
411 if (skb_cow(skb, dst->dev->hard_header_len)) {
412 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
413 goto drop;
414 }
415
416 hdr = skb->nh.ipv6h;
417
418 /* Mangling hops number delayed to point after skb COW */
419
420 hdr->hop_limit--;
421
422 IP6_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS);
423 return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish);
424
425 error:
426 IP6_INC_STATS_BH(IPSTATS_MIB_INADDRERRORS);
427 drop:
428 kfree_skb(skb);
429 return -EINVAL;
430 }
431
432 static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from)
433 {
434 to->pkt_type = from->pkt_type;
435 to->priority = from->priority;
436 to->protocol = from->protocol;
437 dst_release(to->dst);
438 to->dst = dst_clone(from->dst);
439 to->dev = from->dev;
440
441 #ifdef CONFIG_NET_SCHED
442 to->tc_index = from->tc_index;
443 #endif
444 #ifdef CONFIG_NETFILTER
445 to->nfmark = from->nfmark;
446 /* Connection association is same as pre-frag packet */
447 nf_conntrack_put(to->nfct);
448 to->nfct = from->nfct;
449 nf_conntrack_get(to->nfct);
450 to->nfctinfo = from->nfctinfo;
451 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
452 nf_conntrack_put_reasm(to->nfct_reasm);
453 to->nfct_reasm = from->nfct_reasm;
454 nf_conntrack_get_reasm(to->nfct_reasm);
455 #endif
456 #ifdef CONFIG_BRIDGE_NETFILTER
457 nf_bridge_put(to->nf_bridge);
458 to->nf_bridge = from->nf_bridge;
459 nf_bridge_get(to->nf_bridge);
460 #endif
461 #endif
462 }
463
464 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
465 {
466 u16 offset = sizeof(struct ipv6hdr);
467 struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
468 unsigned int packet_len = skb->tail - skb->nh.raw;
469 int found_rhdr = 0;
470 *nexthdr = &skb->nh.ipv6h->nexthdr;
471
472 while (offset + 1 <= packet_len) {
473
474 switch (**nexthdr) {
475
476 case NEXTHDR_HOP:
477 case NEXTHDR_ROUTING:
478 case NEXTHDR_DEST:
479 if (**nexthdr == NEXTHDR_ROUTING) found_rhdr = 1;
480 if (**nexthdr == NEXTHDR_DEST && found_rhdr) return offset;
481 offset += ipv6_optlen(exthdr);
482 *nexthdr = &exthdr->nexthdr;
483 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
484 break;
485 default :
486 return offset;
487 }
488 }
489
490 return offset;
491 }
492 EXPORT_SYMBOL_GPL(ip6_find_1stfragopt);
493
494 static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
495 {
496 struct net_device *dev;
497 struct sk_buff *frag;
498 struct rt6_info *rt = (struct rt6_info*)skb->dst;
499 struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL;
500 struct ipv6hdr *tmp_hdr;
501 struct frag_hdr *fh;
502 unsigned int mtu, hlen, left, len;
503 u32 frag_id = 0;
504 int ptr, offset = 0, err=0;
505 u8 *prevhdr, nexthdr = 0;
506
507 dev = rt->u.dst.dev;
508 hlen = ip6_find_1stfragopt(skb, &prevhdr);
509 nexthdr = *prevhdr;
510
511 mtu = dst_mtu(&rt->u.dst);
512 if (np && np->frag_size < mtu) {
513 if (np->frag_size)
514 mtu = np->frag_size;
515 }
516 mtu -= hlen + sizeof(struct frag_hdr);
517
518 if (skb_shinfo(skb)->frag_list) {
519 int first_len = skb_pagelen(skb);
520
521 if (first_len - hlen > mtu ||
522 ((first_len - hlen) & 7) ||
523 skb_cloned(skb))
524 goto slow_path;
525
526 for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) {
527 /* Correct geometry. */
528 if (frag->len > mtu ||
529 ((frag->len & 7) && frag->next) ||
530 skb_headroom(frag) < hlen)
531 goto slow_path;
532
533 /* Partially cloned skb? */
534 if (skb_shared(frag))
535 goto slow_path;
536
537 BUG_ON(frag->sk);
538 if (skb->sk) {
539 sock_hold(skb->sk);
540 frag->sk = skb->sk;
541 frag->destructor = sock_wfree;
542 skb->truesize -= frag->truesize;
543 }
544 }
545
546 err = 0;
547 offset = 0;
548 frag = skb_shinfo(skb)->frag_list;
549 skb_shinfo(skb)->frag_list = NULL;
550 /* BUILD HEADER */
551
552 tmp_hdr = kmalloc(hlen, GFP_ATOMIC);
553 if (!tmp_hdr) {
554 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
555 return -ENOMEM;
556 }
557
558 *prevhdr = NEXTHDR_FRAGMENT;
559 memcpy(tmp_hdr, skb->nh.raw, hlen);
560 __skb_pull(skb, hlen);
561 fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
562 skb->nh.raw = __skb_push(skb, hlen);
563 memcpy(skb->nh.raw, tmp_hdr, hlen);
564
565 ipv6_select_ident(skb, fh);
566 fh->nexthdr = nexthdr;
567 fh->reserved = 0;
568 fh->frag_off = htons(IP6_MF);
569 frag_id = fh->identification;
570
571 first_len = skb_pagelen(skb);
572 skb->data_len = first_len - skb_headlen(skb);
573 skb->len = first_len;
574 skb->nh.ipv6h->payload_len = htons(first_len - sizeof(struct ipv6hdr));
575
576
577 for (;;) {
578 /* Prepare header of the next frame,
579 * before previous one went down. */
580 if (frag) {
581 frag->ip_summed = CHECKSUM_NONE;
582 frag->h.raw = frag->data;
583 fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
584 frag->nh.raw = __skb_push(frag, hlen);
585 memcpy(frag->nh.raw, tmp_hdr, hlen);
586 offset += skb->len - hlen - sizeof(struct frag_hdr);
587 fh->nexthdr = nexthdr;
588 fh->reserved = 0;
589 fh->frag_off = htons(offset);
590 if (frag->next != NULL)
591 fh->frag_off |= htons(IP6_MF);
592 fh->identification = frag_id;
593 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
594 ip6_copy_metadata(frag, skb);
595 }
596
597 err = output(skb);
598 if (err || !frag)
599 break;
600
601 skb = frag;
602 frag = skb->next;
603 skb->next = NULL;
604 }
605
606 kfree(tmp_hdr);
607
608 if (err == 0) {
609 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS);
610 return 0;
611 }
612
613 while (frag) {
614 skb = frag->next;
615 kfree_skb(frag);
616 frag = skb;
617 }
618
619 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
620 return err;
621 }
622
623 slow_path:
624 left = skb->len - hlen; /* Space per frame */
625 ptr = hlen; /* Where to start from */
626
627 /*
628 * Fragment the datagram.
629 */
630
631 *prevhdr = NEXTHDR_FRAGMENT;
632
633 /*
634 * Keep copying data until we run out.
635 */
636 while(left > 0) {
637 len = left;
638 /* IF: it doesn't fit, use 'mtu' - the data space left */
639 if (len > mtu)
640 len = mtu;
641 /* IF: we are not sending upto and including the packet end
642 then align the next start on an eight byte boundary */
643 if (len < left) {
644 len &= ~7;
645 }
646 /*
647 * Allocate buffer.
648 */
649
650 if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
651 NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n");
652 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
653 err = -ENOMEM;
654 goto fail;
655 }
656
657 /*
658 * Set up data on packet
659 */
660
661 ip6_copy_metadata(frag, skb);
662 skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
663 skb_put(frag, len + hlen + sizeof(struct frag_hdr));
664 frag->nh.raw = frag->data;
665 fh = (struct frag_hdr*)(frag->data + hlen);
666 frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr);
667
668 /*
669 * Charge the memory for the fragment to any owner
670 * it might possess
671 */
672 if (skb->sk)
673 skb_set_owner_w(frag, skb->sk);
674
675 /*
676 * Copy the packet header into the new buffer.
677 */
678 memcpy(frag->nh.raw, skb->data, hlen);
679
680 /*
681 * Build fragment header.
682 */
683 fh->nexthdr = nexthdr;
684 fh->reserved = 0;
685 if (!frag_id) {
686 ipv6_select_ident(skb, fh);
687 frag_id = fh->identification;
688 } else
689 fh->identification = frag_id;
690
691 /*
692 * Copy a block of the IP datagram.
693 */
694 if (skb_copy_bits(skb, ptr, frag->h.raw, len))
695 BUG();
696 left -= len;
697
698 fh->frag_off = htons(offset);
699 if (left > 0)
700 fh->frag_off |= htons(IP6_MF);
701 frag->nh.ipv6h->payload_len = htons(frag->len - sizeof(struct ipv6hdr));
702
703 ptr += len;
704 offset += len;
705
706 /*
707 * Put this fragment into the sending queue.
708 */
709
710 IP6_INC_STATS(IPSTATS_MIB_FRAGCREATES);
711
712 err = output(frag);
713 if (err)
714 goto fail;
715 }
716 kfree_skb(skb);
717 IP6_INC_STATS(IPSTATS_MIB_FRAGOKS);
718 return err;
719
720 fail:
721 kfree_skb(skb);
722 IP6_INC_STATS(IPSTATS_MIB_FRAGFAILS);
723 return err;
724 }
725
726 int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl)
727 {
728 int err = 0;
729
730 *dst = NULL;
731 if (sk) {
732 struct ipv6_pinfo *np = inet6_sk(sk);
733
734 *dst = sk_dst_check(sk, np->dst_cookie);
735 if (*dst) {
736 struct rt6_info *rt = (struct rt6_info*)*dst;
737
738 /* Yes, checking route validity in not connected
739 * case is not very simple. Take into account,
740 * that we do not support routing by source, TOS,
741 * and MSG_DONTROUTE --ANK (980726)
742 *
743 * 1. If route was host route, check that
744 * cached destination is current.
745 * If it is network route, we still may
746 * check its validity using saved pointer
747 * to the last used address: daddr_cache.
748 * We do not want to save whole address now,
749 * (because main consumer of this service
750 * is tcp, which has not this problem),
751 * so that the last trick works only on connected
752 * sockets.
753 * 2. oif also should be the same.
754 */
755 if (((rt->rt6i_dst.plen != 128 ||
756 !ipv6_addr_equal(&fl->fl6_dst,
757 &rt->rt6i_dst.addr))
758 && (np->daddr_cache == NULL ||
759 !ipv6_addr_equal(&fl->fl6_dst,
760 np->daddr_cache)))
761 || (fl->oif && fl->oif != (*dst)->dev->ifindex)) {
762 dst_release(*dst);
763 *dst = NULL;
764 }
765 }
766 }
767
768 if (*dst == NULL)
769 *dst = ip6_route_output(sk, fl);
770
771 if ((err = (*dst)->error))
772 goto out_err_release;
773
774 if (ipv6_addr_any(&fl->fl6_src)) {
775 err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src);
776
777 if (err)
778 goto out_err_release;
779 }
780
781 return 0;
782
783 out_err_release:
784 dst_release(*dst);
785 *dst = NULL;
786 return err;
787 }
788
789 EXPORT_SYMBOL_GPL(ip6_dst_lookup);
790
791 static inline int ip6_ufo_append_data(struct sock *sk,
792 int getfrag(void *from, char *to, int offset, int len,
793 int odd, struct sk_buff *skb),
794 void *from, int length, int hh_len, int fragheaderlen,
795 int transhdrlen, int mtu,unsigned int flags)
796
797 {
798 struct sk_buff *skb;
799 int err;
800
801 /* There is support for UDP large send offload by network
802 * device, so create one single skb packet containing complete
803 * udp datagram
804 */
805 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) {
806 skb = sock_alloc_send_skb(sk,
807 hh_len + fragheaderlen + transhdrlen + 20,
808 (flags & MSG_DONTWAIT), &err);
809 if (skb == NULL)
810 return -ENOMEM;
811
812 /* reserve space for Hardware header */
813 skb_reserve(skb, hh_len);
814
815 /* create space for UDP/IP header */
816 skb_put(skb,fragheaderlen + transhdrlen);
817
818 /* initialize network header pointer */
819 skb->nh.raw = skb->data;
820
821 /* initialize protocol header pointer */
822 skb->h.raw = skb->data + fragheaderlen;
823
824 skb->ip_summed = CHECKSUM_HW;
825 skb->csum = 0;
826 sk->sk_sndmsg_off = 0;
827 }
828
829 err = skb_append_datato_frags(sk,skb, getfrag, from,
830 (length - transhdrlen));
831 if (!err) {
832 struct frag_hdr fhdr;
833
834 /* specify the length of each IP datagram fragment*/
835 skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen) -
836 sizeof(struct frag_hdr);
837 ipv6_select_ident(skb, &fhdr);
838 skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
839 __skb_queue_tail(&sk->sk_write_queue, skb);
840
841 return 0;
842 }
843 /* There is not enough support do UPD LSO,
844 * so follow normal path
845 */
846 kfree_skb(skb);
847
848 return err;
849 }
850
851 int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to,
852 int offset, int len, int odd, struct sk_buff *skb),
853 void *from, int length, int transhdrlen,
854 int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl,
855 struct rt6_info *rt, unsigned int flags)
856 {
857 struct inet_sock *inet = inet_sk(sk);
858 struct ipv6_pinfo *np = inet6_sk(sk);
859 struct sk_buff *skb;
860 unsigned int maxfraglen, fragheaderlen;
861 int exthdrlen;
862 int hh_len;
863 int mtu;
864 int copy;
865 int err;
866 int offset = 0;
867 int csummode = CHECKSUM_NONE;
868
869 if (flags&MSG_PROBE)
870 return 0;
871 if (skb_queue_empty(&sk->sk_write_queue)) {
872 /*
873 * setup for corking
874 */
875 if (opt) {
876 if (np->cork.opt == NULL) {
877 np->cork.opt = kmalloc(opt->tot_len,
878 sk->sk_allocation);
879 if (unlikely(np->cork.opt == NULL))
880 return -ENOBUFS;
881 } else if (np->cork.opt->tot_len < opt->tot_len) {
882 printk(KERN_DEBUG "ip6_append_data: invalid option length\n");
883 return -EINVAL;
884 }
885 memcpy(np->cork.opt, opt, opt->tot_len);
886 inet->cork.flags |= IPCORK_OPT;
887 /* need source address above miyazawa*/
888 }
889 dst_hold(&rt->u.dst);
890 np->cork.rt = rt;
891 inet->cork.fl = *fl;
892 np->cork.hop_limit = hlimit;
893 np->cork.tclass = tclass;
894 mtu = dst_mtu(rt->u.dst.path);
895 if (np->frag_size < mtu) {
896 if (np->frag_size)
897 mtu = np->frag_size;
898 }
899 inet->cork.fragsize = mtu;
900 if (dst_allfrag(rt->u.dst.path))
901 inet->cork.flags |= IPCORK_ALLFRAG;
902 inet->cork.length = 0;
903 sk->sk_sndmsg_page = NULL;
904 sk->sk_sndmsg_off = 0;
905 exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0);
906 length += exthdrlen;
907 transhdrlen += exthdrlen;
908 } else {
909 rt = np->cork.rt;
910 fl = &inet->cork.fl;
911 if (inet->cork.flags & IPCORK_OPT)
912 opt = np->cork.opt;
913 transhdrlen = 0;
914 exthdrlen = 0;
915 mtu = inet->cork.fragsize;
916 }
917
918 hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
919
920 fragheaderlen = sizeof(struct ipv6hdr) + (opt ? opt->opt_nflen : 0);
921 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr);
922
923 if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) {
924 if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) {
925 ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen);
926 return -EMSGSIZE;
927 }
928 }
929
930 /*
931 * Let's try using as much space as possible.
932 * Use MTU if total length of the message fits into the MTU.
933 * Otherwise, we need to reserve fragment header and
934 * fragment alignment (= 8-15 octects, in total).
935 *
936 * Note that we may need to "move" the data from the tail of
937 * of the buffer to the new fragment when we split
938 * the message.
939 *
940 * FIXME: It may be fragmented into multiple chunks
941 * at once if non-fragmentable extension headers
942 * are too large.
943 * --yoshfuji
944 */
945
946 inet->cork.length += length;
947 if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) &&
948 (rt->u.dst.dev->features & NETIF_F_UFO)) {
949
950 err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len,
951 fragheaderlen, transhdrlen, mtu,
952 flags);
953 if (err)
954 goto error;
955 return 0;
956 }
957
958 if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)
959 goto alloc_new_skb;
960
961 while (length > 0) {
962 /* Check if the remaining data fits into current packet. */
963 copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len;
964 if (copy < length)
965 copy = maxfraglen - skb->len;
966
967 if (copy <= 0) {
968 char *data;
969 unsigned int datalen;
970 unsigned int fraglen;
971 unsigned int fraggap;
972 unsigned int alloclen;
973 struct sk_buff *skb_prev;
974 alloc_new_skb:
975 skb_prev = skb;
976
977 /* There's no room in the current skb */
978 if (skb_prev)
979 fraggap = skb_prev->len - maxfraglen;
980 else
981 fraggap = 0;
982
983 /*
984 * If remaining data exceeds the mtu,
985 * we know we need more fragment(s).
986 */
987 datalen = length + fraggap;
988 if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
989 datalen = maxfraglen - fragheaderlen;
990
991 fraglen = datalen + fragheaderlen;
992 if ((flags & MSG_MORE) &&
993 !(rt->u.dst.dev->features&NETIF_F_SG))
994 alloclen = mtu;
995 else
996 alloclen = datalen + fragheaderlen;
997
998 /*
999 * The last fragment gets additional space at tail.
1000 * Note: we overallocate on fragments with MSG_MODE
1001 * because we have no idea if we're the last one.
1002 */
1003 if (datalen == length + fraggap)
1004 alloclen += rt->u.dst.trailer_len;
1005
1006 /*
1007 * We just reserve space for fragment header.
1008 * Note: this may be overallocation if the message
1009 * (without MSG_MORE) fits into the MTU.
1010 */
1011 alloclen += sizeof(struct frag_hdr);
1012
1013 if (transhdrlen) {
1014 skb = sock_alloc_send_skb(sk,
1015 alloclen + hh_len,
1016 (flags & MSG_DONTWAIT), &err);
1017 } else {
1018 skb = NULL;
1019 if (atomic_read(&sk->sk_wmem_alloc) <=
1020 2 * sk->sk_sndbuf)
1021 skb = sock_wmalloc(sk,
1022 alloclen + hh_len, 1,
1023 sk->sk_allocation);
1024 if (unlikely(skb == NULL))
1025 err = -ENOBUFS;
1026 }
1027 if (skb == NULL)
1028 goto error;
1029 /*
1030 * Fill in the control structures
1031 */
1032 skb->ip_summed = csummode;
1033 skb->csum = 0;
1034 /* reserve for fragmentation */
1035 skb_reserve(skb, hh_len+sizeof(struct frag_hdr));
1036
1037 /*
1038 * Find where to start putting bytes
1039 */
1040 data = skb_put(skb, fraglen);
1041 skb->nh.raw = data + exthdrlen;
1042 data += fragheaderlen;
1043 skb->h.raw = data + exthdrlen;
1044
1045 if (fraggap) {
1046 skb->csum = skb_copy_and_csum_bits(
1047 skb_prev, maxfraglen,
1048 data + transhdrlen, fraggap, 0);
1049 skb_prev->csum = csum_sub(skb_prev->csum,
1050 skb->csum);
1051 data += fraggap;
1052 skb_trim(skb_prev, maxfraglen);
1053 }
1054 copy = datalen - transhdrlen - fraggap;
1055 if (copy < 0) {
1056 err = -EINVAL;
1057 kfree_skb(skb);
1058 goto error;
1059 } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1060 err = -EFAULT;
1061 kfree_skb(skb);
1062 goto error;
1063 }
1064
1065 offset += copy;
1066 length -= datalen - fraggap;
1067 transhdrlen = 0;
1068 exthdrlen = 0;
1069 csummode = CHECKSUM_NONE;
1070
1071 /*
1072 * Put the packet on the pending queue
1073 */
1074 __skb_queue_tail(&sk->sk_write_queue, skb);
1075 continue;
1076 }
1077
1078 if (copy > length)
1079 copy = length;
1080
1081 if (!(rt->u.dst.dev->features&NETIF_F_SG)) {
1082 unsigned int off;
1083
1084 off = skb->len;
1085 if (getfrag(from, skb_put(skb, copy),
1086 offset, copy, off, skb) < 0) {
1087 __skb_trim(skb, off);
1088 err = -EFAULT;
1089 goto error;
1090 }
1091 } else {
1092 int i = skb_shinfo(skb)->nr_frags;
1093 skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1];
1094 struct page *page = sk->sk_sndmsg_page;
1095 int off = sk->sk_sndmsg_off;
1096 unsigned int left;
1097
1098 if (page && (left = PAGE_SIZE - off) > 0) {
1099 if (copy >= left)
1100 copy = left;
1101 if (page != frag->page) {
1102 if (i == MAX_SKB_FRAGS) {
1103 err = -EMSGSIZE;
1104 goto error;
1105 }
1106 get_page(page);
1107 skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0);
1108 frag = &skb_shinfo(skb)->frags[i];
1109 }
1110 } else if(i < MAX_SKB_FRAGS) {
1111 if (copy > PAGE_SIZE)
1112 copy = PAGE_SIZE;
1113 page = alloc_pages(sk->sk_allocation, 0);
1114 if (page == NULL) {
1115 err = -ENOMEM;
1116 goto error;
1117 }
1118 sk->sk_sndmsg_page = page;
1119 sk->sk_sndmsg_off = 0;
1120
1121 skb_fill_page_desc(skb, i, page, 0, 0);
1122 frag = &skb_shinfo(skb)->frags[i];
1123 skb->truesize += PAGE_SIZE;
1124 atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
1125 } else {
1126 err = -EMSGSIZE;
1127 goto error;
1128 }
1129 if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) {
1130 err = -EFAULT;
1131 goto error;
1132 }
1133 sk->sk_sndmsg_off += copy;
1134 frag->size += copy;
1135 skb->len += copy;
1136 skb->data_len += copy;
1137 }
1138 offset += copy;
1139 length -= copy;
1140 }
1141 return 0;
1142 error:
1143 inet->cork.length -= length;
1144 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
1145 return err;
1146 }
1147
1148 int ip6_push_pending_frames(struct sock *sk)
1149 {
1150 struct sk_buff *skb, *tmp_skb;
1151 struct sk_buff **tail_skb;
1152 struct in6_addr final_dst_buf, *final_dst = &final_dst_buf;
1153 struct inet_sock *inet = inet_sk(sk);
1154 struct ipv6_pinfo *np = inet6_sk(sk);
1155 struct ipv6hdr *hdr;
1156 struct ipv6_txoptions *opt = np->cork.opt;
1157 struct rt6_info *rt = np->cork.rt;
1158 struct flowi *fl = &inet->cork.fl;
1159 unsigned char proto = fl->proto;
1160 int err = 0;
1161
1162 if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL)
1163 goto out;
1164 tail_skb = &(skb_shinfo(skb)->frag_list);
1165
1166 /* move skb->data to ip header from ext header */
1167 if (skb->data < skb->nh.raw)
1168 __skb_pull(skb, skb->nh.raw - skb->data);
1169 while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
1170 __skb_pull(tmp_skb, skb->h.raw - skb->nh.raw);
1171 *tail_skb = tmp_skb;
1172 tail_skb = &(tmp_skb->next);
1173 skb->len += tmp_skb->len;
1174 skb->data_len += tmp_skb->len;
1175 skb->truesize += tmp_skb->truesize;
1176 __sock_put(tmp_skb->sk);
1177 tmp_skb->destructor = NULL;
1178 tmp_skb->sk = NULL;
1179 }
1180
1181 ipv6_addr_copy(final_dst, &fl->fl6_dst);
1182 __skb_pull(skb, skb->h.raw - skb->nh.raw);
1183 if (opt && opt->opt_flen)
1184 ipv6_push_frag_opts(skb, opt, &proto);
1185 if (opt && opt->opt_nflen)
1186 ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst);
1187
1188 skb->nh.ipv6h = hdr = (struct ipv6hdr*) skb_push(skb, sizeof(struct ipv6hdr));
1189
1190 *(u32*)hdr = fl->fl6_flowlabel |
1191 htonl(0x60000000 | ((int)np->cork.tclass << 20));
1192
1193 if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN)
1194 hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
1195 else
1196 hdr->payload_len = 0;
1197 hdr->hop_limit = np->cork.hop_limit;
1198 hdr->nexthdr = proto;
1199 ipv6_addr_copy(&hdr->saddr, &fl->fl6_src);
1200 ipv6_addr_copy(&hdr->daddr, final_dst);
1201
1202 skb->priority = sk->sk_priority;
1203
1204 skb->dst = dst_clone(&rt->u.dst);
1205 IP6_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
1206 err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output);
1207 if (err) {
1208 if (err > 0)
1209 err = np->recverr ? net_xmit_errno(err) : 0;
1210 if (err)
1211 goto error;
1212 }
1213
1214 out:
1215 inet->cork.flags &= ~IPCORK_OPT;
1216 kfree(np->cork.opt);
1217 np->cork.opt = NULL;
1218 if (np->cork.rt) {
1219 dst_release(&np->cork.rt->u.dst);
1220 np->cork.rt = NULL;
1221 inet->cork.flags &= ~IPCORK_ALLFRAG;
1222 }
1223 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1224 return err;
1225 error:
1226 goto out;
1227 }
1228
1229 void ip6_flush_pending_frames(struct sock *sk)
1230 {
1231 struct inet_sock *inet = inet_sk(sk);
1232 struct ipv6_pinfo *np = inet6_sk(sk);
1233 struct sk_buff *skb;
1234
1235 while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) {
1236 IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
1237 kfree_skb(skb);
1238 }
1239
1240 inet->cork.flags &= ~IPCORK_OPT;
1241
1242 kfree(np->cork.opt);
1243 np->cork.opt = NULL;
1244 if (np->cork.rt) {
1245 dst_release(&np->cork.rt->u.dst);
1246 np->cork.rt = NULL;
1247 inet->cork.flags &= ~IPCORK_ALLFRAG;
1248 }
1249 memset(&inet->cork.fl, 0, sizeof(inet->cork.fl));
1250 }
Ubuntu Focal Linux kernel mirror