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1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * The Internet Protocol (IP) output module.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Donald Becker, <becker@super.org>
11 * Alan Cox, <Alan.Cox@linux.org>
12 * Richard Underwood
13 * Stefan Becker, <stefanb@yello.ping.de>
14 * Jorge Cwik, <jorge@laser.satlink.net>
15 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
16 * Hirokazu Takahashi, <taka@valinux.co.jp>
17 *
18 * See ip_input.c for original log
19 *
20 * Fixes:
21 * Alan Cox : Missing nonblock feature in ip_build_xmit.
22 * Mike Kilburn : htons() missing in ip_build_xmit.
23 * Bradford Johnson: Fix faulty handling of some frames when
24 * no route is found.
25 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit
26 * (in case if packet not accepted by
27 * output firewall rules)
28 * Mike McLagan : Routing by source
29 * Alexey Kuznetsov: use new route cache
30 * Andi Kleen: Fix broken PMTU recovery and remove
31 * some redundant tests.
32 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
33 * Andi Kleen : Replace ip_reply with ip_send_reply.
34 * Andi Kleen : Split fast and slow ip_build_xmit path
35 * for decreased register pressure on x86
36 * and more readibility.
37 * Marc Boucher : When call_out_firewall returns FW_QUEUE,
38 * silently drop skb instead of failing with -EPERM.
39 * Detlev Wengorz : Copy protocol for fragments.
40 * Hirokazu Takahashi: HW checksumming for outgoing UDP
41 * datagrams.
42 * Hirokazu Takahashi: sendfile() on UDP works now.
43 */
44
45#include <linux/uaccess.h>
46#include <linux/module.h>
47#include <linux/types.h>
48#include <linux/kernel.h>
49#include <linux/mm.h>
50#include <linux/string.h>
51#include <linux/errno.h>
52#include <linux/highmem.h>
53#include <linux/slab.h>
54
55#include <linux/socket.h>
56#include <linux/sockios.h>
57#include <linux/in.h>
58#include <linux/inet.h>
59#include <linux/netdevice.h>
60#include <linux/etherdevice.h>
61#include <linux/proc_fs.h>
62#include <linux/stat.h>
63#include <linux/init.h>
64
65#include <net/snmp.h>
66#include <net/ip.h>
67#include <net/protocol.h>
68#include <net/route.h>
69#include <net/xfrm.h>
70#include <linux/skbuff.h>
71#include <net/sock.h>
72#include <net/arp.h>
73#include <net/icmp.h>
74#include <net/checksum.h>
75#include <net/inetpeer.h>
76#include <net/lwtunnel.h>
77#include <linux/bpf-cgroup.h>
78#include <linux/igmp.h>
79#include <linux/netfilter_ipv4.h>
80#include <linux/netfilter_bridge.h>
81#include <linux/netlink.h>
82#include <linux/tcp.h>
83
84static int
85ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
86 unsigned int mtu,
87 int (*output)(struct net *, struct sock *, struct sk_buff *));
88
89/* Generate a checksum for an outgoing IP datagram. */
90void ip_send_check(struct iphdr *iph)
91{
92 iph->check = 0;
93 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
94}
95EXPORT_SYMBOL(ip_send_check);
96
97int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
98{
99 struct iphdr *iph = ip_hdr(skb);
100
101 iph->tot_len = htons(skb->len);
102 ip_send_check(iph);
103
104 /* if egress device is enslaved to an L3 master device pass the
105 * skb to its handler for processing
106 */
107 skb = l3mdev_ip_out(sk, skb);
108 if (unlikely(!skb))
109 return 0;
110
111 skb->protocol = htons(ETH_P_IP);
112
113 return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT,
114 net, sk, skb, NULL, skb_dst(skb)->dev,
115 dst_output);
116}
117
118int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
119{
120 int err;
121
122 err = __ip_local_out(net, sk, skb);
123 if (likely(err == 1))
124 err = dst_output(net, sk, skb);
125
126 return err;
127}
128EXPORT_SYMBOL_GPL(ip_local_out);
129
130static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
131{
132 int ttl = inet->uc_ttl;
133
134 if (ttl < 0)
135 ttl = ip4_dst_hoplimit(dst);
136 return ttl;
137}
138
139/*
140 * Add an ip header to a skbuff and send it out.
141 *
142 */
143int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
144 __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
145{
146 struct inet_sock *inet = inet_sk(sk);
147 struct rtable *rt = skb_rtable(skb);
148 struct net *net = sock_net(sk);
149 struct iphdr *iph;
150
151 /* Build the IP header. */
152 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
153 skb_reset_network_header(skb);
154 iph = ip_hdr(skb);
155 iph->version = 4;
156 iph->ihl = 5;
157 iph->tos = inet->tos;
158 iph->ttl = ip_select_ttl(inet, &rt->dst);
159 iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
160 iph->saddr = saddr;
161 iph->protocol = sk->sk_protocol;
162 if (ip_dont_fragment(sk, &rt->dst)) {
163 iph->frag_off = htons(IP_DF);
164 iph->id = 0;
165 } else {
166 iph->frag_off = 0;
167 __ip_select_ident(net, iph, 1);
168 }
169
170 if (opt && opt->opt.optlen) {
171 iph->ihl += opt->opt.optlen>>2;
172 ip_options_build(skb, &opt->opt, daddr, rt, 0);
173 }
174
175 skb->priority = sk->sk_priority;
176 if (!skb->mark)
177 skb->mark = sk->sk_mark;
178
179 /* Send it out. */
180 return ip_local_out(net, skb->sk, skb);
181}
182EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
183
184static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
185{
186 struct dst_entry *dst = skb_dst(skb);
187 struct rtable *rt = (struct rtable *)dst;
188 struct net_device *dev = dst->dev;
189 unsigned int hh_len = LL_RESERVED_SPACE(dev);
190 struct neighbour *neigh;
191 u32 nexthop;
192
193 if (rt->rt_type == RTN_MULTICAST) {
194 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len);
195 } else if (rt->rt_type == RTN_BROADCAST)
196 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len);
197
198 /* Be paranoid, rather than too clever. */
199 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
200 struct sk_buff *skb2;
201
202 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
203 if (!skb2) {
204 kfree_skb(skb);
205 return -ENOMEM;
206 }
207 if (skb->sk)
208 skb_set_owner_w(skb2, skb->sk);
209 consume_skb(skb);
210 skb = skb2;
211 }
212
213 if (lwtunnel_xmit_redirect(dst->lwtstate)) {
214 int res = lwtunnel_xmit(skb);
215
216 if (res < 0 || res == LWTUNNEL_XMIT_DONE)
217 return res;
218 }
219
220 rcu_read_lock_bh();
221 nexthop = (__force u32) rt_nexthop(rt, ip_hdr(skb)->daddr);
222 neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
223 if (unlikely(!neigh))
224 neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
225 if (!IS_ERR(neigh)) {
226 int res;
227
228 sock_confirm_neigh(skb, neigh);
229 res = neigh_output(neigh, skb);
230
231 rcu_read_unlock_bh();
232 return res;
233 }
234 rcu_read_unlock_bh();
235
236 net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
237 __func__);
238 kfree_skb(skb);
239 return -EINVAL;
240}
241
242static int ip_finish_output_gso(struct net *net, struct sock *sk,
243 struct sk_buff *skb, unsigned int mtu)
244{
245 netdev_features_t features;
246 struct sk_buff *segs;
247 int ret = 0;
248
249 /* common case: seglen is <= mtu
250 */
251 if (skb_gso_validate_network_len(skb, mtu))
252 return ip_finish_output2(net, sk, skb);
253
254 /* Slowpath - GSO segment length exceeds the egress MTU.
255 *
256 * This can happen in several cases:
257 * - Forwarding of a TCP GRO skb, when DF flag is not set.
258 * - Forwarding of an skb that arrived on a virtualization interface
259 * (virtio-net/vhost/tap) with TSO/GSO size set by other network
260 * stack.
261 * - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an
262 * interface with a smaller MTU.
263 * - Arriving GRO skb (or GSO skb in a virtualized environment) that is
264 * bridged to a NETIF_F_TSO tunnel stacked over an interface with an
265 * insufficent MTU.
266 */
267 features = netif_skb_features(skb);
268 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
269 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
270 if (IS_ERR_OR_NULL(segs)) {
271 kfree_skb(skb);
272 return -ENOMEM;
273 }
274
275 consume_skb(skb);
276
277 do {
278 struct sk_buff *nskb = segs->next;
279 int err;
280
281 segs->next = NULL;
282 err = ip_fragment(net, sk, segs, mtu, ip_finish_output2);
283
284 if (err && ret == 0)
285 ret = err;
286 segs = nskb;
287 } while (segs);
288
289 return ret;
290}
291
292static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
293{
294 unsigned int mtu;
295 int ret;
296
297 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
298 if (ret) {
299 kfree_skb(skb);
300 return ret;
301 }
302
303#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
304 /* Policy lookup after SNAT yielded a new policy */
305 if (skb_dst(skb)->xfrm) {
306 IPCB(skb)->flags |= IPSKB_REROUTED;
307 return dst_output(net, sk, skb);
308 }
309#endif
310 mtu = ip_skb_dst_mtu(sk, skb);
311 if (skb_is_gso(skb))
312 return ip_finish_output_gso(net, sk, skb, mtu);
313
314 if (skb->len > mtu || (IPCB(skb)->flags & IPSKB_FRAG_PMTU))
315 return ip_fragment(net, sk, skb, mtu, ip_finish_output2);
316
317 return ip_finish_output2(net, sk, skb);
318}
319
320static int ip_mc_finish_output(struct net *net, struct sock *sk,
321 struct sk_buff *skb)
322{
323 int ret;
324
325 ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
326 if (ret) {
327 kfree_skb(skb);
328 return ret;
329 }
330
331 return dev_loopback_xmit(net, sk, skb);
332}
333
334int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb)
335{
336 struct rtable *rt = skb_rtable(skb);
337 struct net_device *dev = rt->dst.dev;
338
339 /*
340 * If the indicated interface is up and running, send the packet.
341 */
342 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
343
344 skb->dev = dev;
345 skb->protocol = htons(ETH_P_IP);
346
347 /*
348 * Multicasts are looped back for other local users
349 */
350
351 if (rt->rt_flags&RTCF_MULTICAST) {
352 if (sk_mc_loop(sk)
353#ifdef CONFIG_IP_MROUTE
354 /* Small optimization: do not loopback not local frames,
355 which returned after forwarding; they will be dropped
356 by ip_mr_input in any case.
357 Note, that local frames are looped back to be delivered
358 to local recipients.
359
360 This check is duplicated in ip_mr_input at the moment.
361 */
362 &&
363 ((rt->rt_flags & RTCF_LOCAL) ||
364 !(IPCB(skb)->flags & IPSKB_FORWARDED))
365#endif
366 ) {
367 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
368 if (newskb)
369 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
370 net, sk, newskb, NULL, newskb->dev,
371 ip_mc_finish_output);
372 }
373
374 /* Multicasts with ttl 0 must not go beyond the host */
375
376 if (ip_hdr(skb)->ttl == 0) {
377 kfree_skb(skb);
378 return 0;
379 }
380 }
381
382 if (rt->rt_flags&RTCF_BROADCAST) {
383 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
384 if (newskb)
385 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
386 net, sk, newskb, NULL, newskb->dev,
387 ip_mc_finish_output);
388 }
389
390 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
391 net, sk, skb, NULL, skb->dev,
392 ip_finish_output,
393 !(IPCB(skb)->flags & IPSKB_REROUTED));
394}
395
396int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb)
397{
398 struct net_device *dev = skb_dst(skb)->dev;
399
400 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
401
402 skb->dev = dev;
403 skb->protocol = htons(ETH_P_IP);
404
405 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
406 net, sk, skb, NULL, dev,
407 ip_finish_output,
408 !(IPCB(skb)->flags & IPSKB_REROUTED));
409}
410
411/*
412 * copy saddr and daddr, possibly using 64bit load/stores
413 * Equivalent to :
414 * iph->saddr = fl4->saddr;
415 * iph->daddr = fl4->daddr;
416 */
417static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
418{
419 BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
420 offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
421 memcpy(&iph->saddr, &fl4->saddr,
422 sizeof(fl4->saddr) + sizeof(fl4->daddr));
423}
424
425/* Note: skb->sk can be different from sk, in case of tunnels */
426int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
427{
428 struct inet_sock *inet = inet_sk(sk);
429 struct net *net = sock_net(sk);
430 struct ip_options_rcu *inet_opt;
431 struct flowi4 *fl4;
432 struct rtable *rt;
433 struct iphdr *iph;
434 int res;
435
436 /* Skip all of this if the packet is already routed,
437 * f.e. by something like SCTP.
438 */
439 rcu_read_lock();
440 inet_opt = rcu_dereference(inet->inet_opt);
441 fl4 = &fl->u.ip4;
442 rt = skb_rtable(skb);
443 if (rt)
444 goto packet_routed;
445
446 /* Make sure we can route this packet. */
447 rt = (struct rtable *)__sk_dst_check(sk, 0);
448 if (!rt) {
449 __be32 daddr;
450
451 /* Use correct destination address if we have options. */
452 daddr = inet->inet_daddr;
453 if (inet_opt && inet_opt->opt.srr)
454 daddr = inet_opt->opt.faddr;
455
456 /* If this fails, retransmit mechanism of transport layer will
457 * keep trying until route appears or the connection times
458 * itself out.
459 */
460 rt = ip_route_output_ports(net, fl4, sk,
461 daddr, inet->inet_saddr,
462 inet->inet_dport,
463 inet->inet_sport,
464 sk->sk_protocol,
465 RT_CONN_FLAGS(sk),
466 sk->sk_bound_dev_if);
467 if (IS_ERR(rt))
468 goto no_route;
469 sk_setup_caps(sk, &rt->dst);
470 }
471 skb_dst_set_noref(skb, &rt->dst);
472
473packet_routed:
474 if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
475 goto no_route;
476
477 /* OK, we know where to send it, allocate and build IP header. */
478 skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
479 skb_reset_network_header(skb);
480 iph = ip_hdr(skb);
481 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
482 if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df)
483 iph->frag_off = htons(IP_DF);
484 else
485 iph->frag_off = 0;
486 iph->ttl = ip_select_ttl(inet, &rt->dst);
487 iph->protocol = sk->sk_protocol;
488 ip_copy_addrs(iph, fl4);
489
490 /* Transport layer set skb->h.foo itself. */
491
492 if (inet_opt && inet_opt->opt.optlen) {
493 iph->ihl += inet_opt->opt.optlen >> 2;
494 ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
495 }
496
497 ip_select_ident_segs(net, skb, sk,
498 skb_shinfo(skb)->gso_segs ?: 1);
499
500 /* TODO : should we use skb->sk here instead of sk ? */
501 skb->priority = sk->sk_priority;
502 skb->mark = sk->sk_mark;
503
504 res = ip_local_out(net, sk, skb);
505 rcu_read_unlock();
506 return res;
507
508no_route:
509 rcu_read_unlock();
510 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
511 kfree_skb(skb);
512 return -EHOSTUNREACH;
513}
514EXPORT_SYMBOL(ip_queue_xmit);
515
516static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
517{
518 to->pkt_type = from->pkt_type;
519 to->priority = from->priority;
520 to->protocol = from->protocol;
521 skb_dst_drop(to);
522 skb_dst_copy(to, from);
523 to->dev = from->dev;
524 to->mark = from->mark;
525
526 /* Copy the flags to each fragment. */
527 IPCB(to)->flags = IPCB(from)->flags;
528
529#ifdef CONFIG_NET_SCHED
530 to->tc_index = from->tc_index;
531#endif
532 nf_copy(to, from);
533#if IS_ENABLED(CONFIG_IP_VS)
534 to->ipvs_property = from->ipvs_property;
535#endif
536 skb_copy_secmark(to, from);
537}
538
539static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
540 unsigned int mtu,
541 int (*output)(struct net *, struct sock *, struct sk_buff *))
542{
543 struct iphdr *iph = ip_hdr(skb);
544
545 if ((iph->frag_off & htons(IP_DF)) == 0)
546 return ip_do_fragment(net, sk, skb, output);
547
548 if (unlikely(!skb->ignore_df ||
549 (IPCB(skb)->frag_max_size &&
550 IPCB(skb)->frag_max_size > mtu))) {
551 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
552 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
553 htonl(mtu));
554 kfree_skb(skb);
555 return -EMSGSIZE;
556 }
557
558 return ip_do_fragment(net, sk, skb, output);
559}
560
561/*
562 * This IP datagram is too large to be sent in one piece. Break it up into
563 * smaller pieces (each of size equal to IP header plus
564 * a block of the data of the original IP data part) that will yet fit in a
565 * single device frame, and queue such a frame for sending.
566 */
567
568int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
569 int (*output)(struct net *, struct sock *, struct sk_buff *))
570{
571 struct iphdr *iph;
572 int ptr;
573 struct sk_buff *skb2;
574 unsigned int mtu, hlen, left, len, ll_rs;
575 int offset;
576 __be16 not_last_frag;
577 struct rtable *rt = skb_rtable(skb);
578 int err = 0;
579
580 /* for offloaded checksums cleanup checksum before fragmentation */
581 if (skb->ip_summed == CHECKSUM_PARTIAL &&
582 (err = skb_checksum_help(skb)))
583 goto fail;
584
585 /*
586 * Point into the IP datagram header.
587 */
588
589 iph = ip_hdr(skb);
590
591 mtu = ip_skb_dst_mtu(sk, skb);
592 if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu)
593 mtu = IPCB(skb)->frag_max_size;
594
595 /*
596 * Setup starting values.
597 */
598
599 hlen = iph->ihl * 4;
600 mtu = mtu - hlen; /* Size of data space */
601 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
602 ll_rs = LL_RESERVED_SPACE(rt->dst.dev);
603
604 /* When frag_list is given, use it. First, check its validity:
605 * some transformers could create wrong frag_list or break existing
606 * one, it is not prohibited. In this case fall back to copying.
607 *
608 * LATER: this step can be merged to real generation of fragments,
609 * we can switch to copy when see the first bad fragment.
610 */
611 if (skb_has_frag_list(skb)) {
612 struct sk_buff *frag, *frag2;
613 unsigned int first_len = skb_pagelen(skb);
614
615 if (first_len - hlen > mtu ||
616 ((first_len - hlen) & 7) ||
617 ip_is_fragment(iph) ||
618 skb_cloned(skb) ||
619 skb_headroom(skb) < ll_rs)
620 goto slow_path;
621
622 skb_walk_frags(skb, frag) {
623 /* Correct geometry. */
624 if (frag->len > mtu ||
625 ((frag->len & 7) && frag->next) ||
626 skb_headroom(frag) < hlen + ll_rs)
627 goto slow_path_clean;
628
629 /* Partially cloned skb? */
630 if (skb_shared(frag))
631 goto slow_path_clean;
632
633 BUG_ON(frag->sk);
634 if (skb->sk) {
635 frag->sk = skb->sk;
636 frag->destructor = sock_wfree;
637 }
638 skb->truesize -= frag->truesize;
639 }
640
641 /* Everything is OK. Generate! */
642
643 err = 0;
644 offset = 0;
645 frag = skb_shinfo(skb)->frag_list;
646 skb_frag_list_init(skb);
647 skb->data_len = first_len - skb_headlen(skb);
648 skb->len = first_len;
649 iph->tot_len = htons(first_len);
650 iph->frag_off = htons(IP_MF);
651 ip_send_check(iph);
652
653 for (;;) {
654 /* Prepare header of the next frame,
655 * before previous one went down. */
656 if (frag) {
657 frag->ip_summed = CHECKSUM_NONE;
658 skb_reset_transport_header(frag);
659 __skb_push(frag, hlen);
660 skb_reset_network_header(frag);
661 memcpy(skb_network_header(frag), iph, hlen);
662 iph = ip_hdr(frag);
663 iph->tot_len = htons(frag->len);
664 ip_copy_metadata(frag, skb);
665 if (offset == 0)
666 ip_options_fragment(frag);
667 offset += skb->len - hlen;
668 iph->frag_off = htons(offset>>3);
669 if (frag->next)
670 iph->frag_off |= htons(IP_MF);
671 /* Ready, complete checksum */
672 ip_send_check(iph);
673 }
674
675 err = output(net, sk, skb);
676
677 if (!err)
678 IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
679 if (err || !frag)
680 break;
681
682 skb = frag;
683 frag = skb->next;
684 skb->next = NULL;
685 }
686
687 if (err == 0) {
688 IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS);
689 return 0;
690 }
691
692 while (frag) {
693 skb = frag->next;
694 kfree_skb(frag);
695 frag = skb;
696 }
697 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
698 return err;
699
700slow_path_clean:
701 skb_walk_frags(skb, frag2) {
702 if (frag2 == frag)
703 break;
704 frag2->sk = NULL;
705 frag2->destructor = NULL;
706 skb->truesize += frag2->truesize;
707 }
708 }
709
710slow_path:
711 iph = ip_hdr(skb);
712
713 left = skb->len - hlen; /* Space per frame */
714 ptr = hlen; /* Where to start from */
715
716 /*
717 * Fragment the datagram.
718 */
719
720 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
721 not_last_frag = iph->frag_off & htons(IP_MF);
722
723 /*
724 * Keep copying data until we run out.
725 */
726
727 while (left > 0) {
728 len = left;
729 /* IF: it doesn't fit, use 'mtu' - the data space left */
730 if (len > mtu)
731 len = mtu;
732 /* IF: we are not sending up to and including the packet end
733 then align the next start on an eight byte boundary */
734 if (len < left) {
735 len &= ~7;
736 }
737
738 /* Allocate buffer */
739 skb2 = alloc_skb(len + hlen + ll_rs, GFP_ATOMIC);
740 if (!skb2) {
741 err = -ENOMEM;
742 goto fail;
743 }
744
745 /*
746 * Set up data on packet
747 */
748
749 ip_copy_metadata(skb2, skb);
750 skb_reserve(skb2, ll_rs);
751 skb_put(skb2, len + hlen);
752 skb_reset_network_header(skb2);
753 skb2->transport_header = skb2->network_header + hlen;
754
755 /*
756 * Charge the memory for the fragment to any owner
757 * it might possess
758 */
759
760 if (skb->sk)
761 skb_set_owner_w(skb2, skb->sk);
762
763 /*
764 * Copy the packet header into the new buffer.
765 */
766
767 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
768
769 /*
770 * Copy a block of the IP datagram.
771 */
772 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
773 BUG();
774 left -= len;
775
776 /*
777 * Fill in the new header fields.
778 */
779 iph = ip_hdr(skb2);
780 iph->frag_off = htons((offset >> 3));
781
782 if (IPCB(skb)->flags & IPSKB_FRAG_PMTU)
783 iph->frag_off |= htons(IP_DF);
784
785 /* ANK: dirty, but effective trick. Upgrade options only if
786 * the segment to be fragmented was THE FIRST (otherwise,
787 * options are already fixed) and make it ONCE
788 * on the initial skb, so that all the following fragments
789 * will inherit fixed options.
790 */
791 if (offset == 0)
792 ip_options_fragment(skb);
793
794 /*
795 * Added AC : If we are fragmenting a fragment that's not the
796 * last fragment then keep MF on each bit
797 */
798 if (left > 0 || not_last_frag)
799 iph->frag_off |= htons(IP_MF);
800 ptr += len;
801 offset += len;
802
803 /*
804 * Put this fragment into the sending queue.
805 */
806 iph->tot_len = htons(len + hlen);
807
808 ip_send_check(iph);
809
810 err = output(net, sk, skb2);
811 if (err)
812 goto fail;
813
814 IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
815 }
816 consume_skb(skb);
817 IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS);
818 return err;
819
820fail:
821 kfree_skb(skb);
822 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
823 return err;
824}
825EXPORT_SYMBOL(ip_do_fragment);
826
827int
828ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
829{
830 struct msghdr *msg = from;
831
832 if (skb->ip_summed == CHECKSUM_PARTIAL) {
833 if (!copy_from_iter_full(to, len, &msg->msg_iter))
834 return -EFAULT;
835 } else {
836 __wsum csum = 0;
837 if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter))
838 return -EFAULT;
839 skb->csum = csum_block_add(skb->csum, csum, odd);
840 }
841 return 0;
842}
843EXPORT_SYMBOL(ip_generic_getfrag);
844
845static inline __wsum
846csum_page(struct page *page, int offset, int copy)
847{
848 char *kaddr;
849 __wsum csum;
850 kaddr = kmap(page);
851 csum = csum_partial(kaddr + offset, copy, 0);
852 kunmap(page);
853 return csum;
854}
855
856static int __ip_append_data(struct sock *sk,
857 struct flowi4 *fl4,
858 struct sk_buff_head *queue,
859 struct inet_cork *cork,
860 struct page_frag *pfrag,
861 int getfrag(void *from, char *to, int offset,
862 int len, int odd, struct sk_buff *skb),
863 void *from, int length, int transhdrlen,
864 unsigned int flags)
865{
866 struct inet_sock *inet = inet_sk(sk);
867 struct sk_buff *skb;
868
869 struct ip_options *opt = cork->opt;
870 int hh_len;
871 int exthdrlen;
872 int mtu;
873 int copy;
874 int err;
875 int offset = 0;
876 unsigned int maxfraglen, fragheaderlen, maxnonfragsize;
877 int csummode = CHECKSUM_NONE;
878 struct rtable *rt = (struct rtable *)cork->dst;
879 unsigned int wmem_alloc_delta = 0;
880 u32 tskey = 0;
881
882 skb = skb_peek_tail(queue);
883
884 exthdrlen = !skb ? rt->dst.header_len : 0;
885 mtu = cork->fragsize;
886 if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP &&
887 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
888 tskey = sk->sk_tskey++;
889
890 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
891
892 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
893 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
894 maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu;
895
896 if (cork->length + length > maxnonfragsize - fragheaderlen) {
897 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
898 mtu - (opt ? opt->optlen : 0));
899 return -EMSGSIZE;
900 }
901
902 /*
903 * transhdrlen > 0 means that this is the first fragment and we wish
904 * it won't be fragmented in the future.
905 */
906 if (transhdrlen &&
907 length + fragheaderlen <= mtu &&
908 rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) &&
909 !(flags & MSG_MORE) &&
910 !exthdrlen)
911 csummode = CHECKSUM_PARTIAL;
912
913 cork->length += length;
914
915 /* So, what's going on in the loop below?
916 *
917 * We use calculated fragment length to generate chained skb,
918 * each of segments is IP fragment ready for sending to network after
919 * adding appropriate IP header.
920 */
921
922 if (!skb)
923 goto alloc_new_skb;
924
925 while (length > 0) {
926 /* Check if the remaining data fits into current packet. */
927 copy = mtu - skb->len;
928 if (copy < length)
929 copy = maxfraglen - skb->len;
930 if (copy <= 0) {
931 char *data;
932 unsigned int datalen;
933 unsigned int fraglen;
934 unsigned int fraggap;
935 unsigned int alloclen;
936 struct sk_buff *skb_prev;
937alloc_new_skb:
938 skb_prev = skb;
939 if (skb_prev)
940 fraggap = skb_prev->len - maxfraglen;
941 else
942 fraggap = 0;
943
944 /*
945 * If remaining data exceeds the mtu,
946 * we know we need more fragment(s).
947 */
948 datalen = length + fraggap;
949 if (datalen > mtu - fragheaderlen)
950 datalen = maxfraglen - fragheaderlen;
951 fraglen = datalen + fragheaderlen;
952
953 if ((flags & MSG_MORE) &&
954 !(rt->dst.dev->features&NETIF_F_SG))
955 alloclen = mtu;
956 else
957 alloclen = fraglen;
958
959 alloclen += exthdrlen;
960
961 /* The last fragment gets additional space at tail.
962 * Note, with MSG_MORE we overallocate on fragments,
963 * because we have no idea what fragment will be
964 * the last.
965 */
966 if (datalen == length + fraggap)
967 alloclen += rt->dst.trailer_len;
968
969 if (transhdrlen) {
970 skb = sock_alloc_send_skb(sk,
971 alloclen + hh_len + 15,
972 (flags & MSG_DONTWAIT), &err);
973 } else {
974 skb = NULL;
975 if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
976 2 * sk->sk_sndbuf)
977 skb = alloc_skb(alloclen + hh_len + 15,
978 sk->sk_allocation);
979 if (unlikely(!skb))
980 err = -ENOBUFS;
981 }
982 if (!skb)
983 goto error;
984
985 /*
986 * Fill in the control structures
987 */
988 skb->ip_summed = csummode;
989 skb->csum = 0;
990 skb_reserve(skb, hh_len);
991
992 /* only the initial fragment is time stamped */
993 skb_shinfo(skb)->tx_flags = cork->tx_flags;
994 cork->tx_flags = 0;
995 skb_shinfo(skb)->tskey = tskey;
996 tskey = 0;
997
998 /*
999 * Find where to start putting bytes.
1000 */
1001 data = skb_put(skb, fraglen + exthdrlen);
1002 skb_set_network_header(skb, exthdrlen);
1003 skb->transport_header = (skb->network_header +
1004 fragheaderlen);
1005 data += fragheaderlen + exthdrlen;
1006
1007 if (fraggap) {
1008 skb->csum = skb_copy_and_csum_bits(
1009 skb_prev, maxfraglen,
1010 data + transhdrlen, fraggap, 0);
1011 skb_prev->csum = csum_sub(skb_prev->csum,
1012 skb->csum);
1013 data += fraggap;
1014 pskb_trim_unique(skb_prev, maxfraglen);
1015 }
1016
1017 copy = datalen - transhdrlen - fraggap;
1018 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1019 err = -EFAULT;
1020 kfree_skb(skb);
1021 goto error;
1022 }
1023
1024 offset += copy;
1025 length -= datalen - fraggap;
1026 transhdrlen = 0;
1027 exthdrlen = 0;
1028 csummode = CHECKSUM_NONE;
1029
1030 if ((flags & MSG_CONFIRM) && !skb_prev)
1031 skb_set_dst_pending_confirm(skb, 1);
1032
1033 /*
1034 * Put the packet on the pending queue.
1035 */
1036 if (!skb->destructor) {
1037 skb->destructor = sock_wfree;
1038 skb->sk = sk;
1039 wmem_alloc_delta += skb->truesize;
1040 }
1041 __skb_queue_tail(queue, skb);
1042 continue;
1043 }
1044
1045 if (copy > length)
1046 copy = length;
1047
1048 if (!(rt->dst.dev->features&NETIF_F_SG) &&
1049 skb_tailroom(skb) >= copy) {
1050 unsigned int off;
1051
1052 off = skb->len;
1053 if (getfrag(from, skb_put(skb, copy),
1054 offset, copy, off, skb) < 0) {
1055 __skb_trim(skb, off);
1056 err = -EFAULT;
1057 goto error;
1058 }
1059 } else {
1060 int i = skb_shinfo(skb)->nr_frags;
1061
1062 err = -ENOMEM;
1063 if (!sk_page_frag_refill(sk, pfrag))
1064 goto error;
1065
1066 if (!skb_can_coalesce(skb, i, pfrag->page,
1067 pfrag->offset)) {
1068 err = -EMSGSIZE;
1069 if (i == MAX_SKB_FRAGS)
1070 goto error;
1071
1072 __skb_fill_page_desc(skb, i, pfrag->page,
1073 pfrag->offset, 0);
1074 skb_shinfo(skb)->nr_frags = ++i;
1075 get_page(pfrag->page);
1076 }
1077 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1078 if (getfrag(from,
1079 page_address(pfrag->page) + pfrag->offset,
1080 offset, copy, skb->len, skb) < 0)
1081 goto error_efault;
1082
1083 pfrag->offset += copy;
1084 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1085 skb->len += copy;
1086 skb->data_len += copy;
1087 skb->truesize += copy;
1088 wmem_alloc_delta += copy;
1089 }
1090 offset += copy;
1091 length -= copy;
1092 }
1093
1094 if (wmem_alloc_delta)
1095 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1096 return 0;
1097
1098error_efault:
1099 err = -EFAULT;
1100error:
1101 cork->length -= length;
1102 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1103 refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
1104 return err;
1105}
1106
1107static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
1108 struct ipcm_cookie *ipc, struct rtable **rtp)
1109{
1110 struct ip_options_rcu *opt;
1111 struct rtable *rt;
1112
1113 rt = *rtp;
1114 if (unlikely(!rt))
1115 return -EFAULT;
1116
1117 /*
1118 * setup for corking.
1119 */
1120 opt = ipc->opt;
1121 if (opt) {
1122 if (!cork->opt) {
1123 cork->opt = kmalloc(sizeof(struct ip_options) + 40,
1124 sk->sk_allocation);
1125 if (unlikely(!cork->opt))
1126 return -ENOBUFS;
1127 }
1128 memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
1129 cork->flags |= IPCORK_OPT;
1130 cork->addr = ipc->addr;
1131 }
1132
1133 /*
1134 * We steal reference to this route, caller should not release it
1135 */
1136 *rtp = NULL;
1137 cork->fragsize = ip_sk_use_pmtu(sk) ?
1138 dst_mtu(&rt->dst) : rt->dst.dev->mtu;
1139 cork->dst = &rt->dst;
1140 cork->length = 0;
1141 cork->ttl = ipc->ttl;
1142 cork->tos = ipc->tos;
1143 cork->priority = ipc->priority;
1144 cork->tx_flags = ipc->tx_flags;
1145
1146 return 0;
1147}
1148
1149/*
1150 * ip_append_data() and ip_append_page() can make one large IP datagram
1151 * from many pieces of data. Each pieces will be holded on the socket
1152 * until ip_push_pending_frames() is called. Each piece can be a page
1153 * or non-page data.
1154 *
1155 * Not only UDP, other transport protocols - e.g. raw sockets - can use
1156 * this interface potentially.
1157 *
1158 * LATER: length must be adjusted by pad at tail, when it is required.
1159 */
1160int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1161 int getfrag(void *from, char *to, int offset, int len,
1162 int odd, struct sk_buff *skb),
1163 void *from, int length, int transhdrlen,
1164 struct ipcm_cookie *ipc, struct rtable **rtp,
1165 unsigned int flags)
1166{
1167 struct inet_sock *inet = inet_sk(sk);
1168 int err;
1169
1170 if (flags&MSG_PROBE)
1171 return 0;
1172
1173 if (skb_queue_empty(&sk->sk_write_queue)) {
1174 err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
1175 if (err)
1176 return err;
1177 } else {
1178 transhdrlen = 0;
1179 }
1180
1181 return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base,
1182 sk_page_frag(sk), getfrag,
1183 from, length, transhdrlen, flags);
1184}
1185
1186ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1187 int offset, size_t size, int flags)
1188{
1189 struct inet_sock *inet = inet_sk(sk);
1190 struct sk_buff *skb;
1191 struct rtable *rt;
1192 struct ip_options *opt = NULL;
1193 struct inet_cork *cork;
1194 int hh_len;
1195 int mtu;
1196 int len;
1197 int err;
1198 unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize;
1199
1200 if (inet->hdrincl)
1201 return -EPERM;
1202
1203 if (flags&MSG_PROBE)
1204 return 0;
1205
1206 if (skb_queue_empty(&sk->sk_write_queue))
1207 return -EINVAL;
1208
1209 cork = &inet->cork.base;
1210 rt = (struct rtable *)cork->dst;
1211 if (cork->flags & IPCORK_OPT)
1212 opt = cork->opt;
1213
1214 if (!(rt->dst.dev->features&NETIF_F_SG))
1215 return -EOPNOTSUPP;
1216
1217 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1218 mtu = cork->fragsize;
1219
1220 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1221 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1222 maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu;
1223
1224 if (cork->length + size > maxnonfragsize - fragheaderlen) {
1225 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
1226 mtu - (opt ? opt->optlen : 0));
1227 return -EMSGSIZE;
1228 }
1229
1230 skb = skb_peek_tail(&sk->sk_write_queue);
1231 if (!skb)
1232 return -EINVAL;
1233
1234 cork->length += size;
1235
1236 while (size > 0) {
1237 /* Check if the remaining data fits into current packet. */
1238 len = mtu - skb->len;
1239 if (len < size)
1240 len = maxfraglen - skb->len;
1241
1242 if (len <= 0) {
1243 struct sk_buff *skb_prev;
1244 int alloclen;
1245
1246 skb_prev = skb;
1247 fraggap = skb_prev->len - maxfraglen;
1248
1249 alloclen = fragheaderlen + hh_len + fraggap + 15;
1250 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1251 if (unlikely(!skb)) {
1252 err = -ENOBUFS;
1253 goto error;
1254 }
1255
1256 /*
1257 * Fill in the control structures
1258 */
1259 skb->ip_summed = CHECKSUM_NONE;
1260 skb->csum = 0;
1261 skb_reserve(skb, hh_len);
1262
1263 /*
1264 * Find where to start putting bytes.
1265 */
1266 skb_put(skb, fragheaderlen + fraggap);
1267 skb_reset_network_header(skb);
1268 skb->transport_header = (skb->network_header +
1269 fragheaderlen);
1270 if (fraggap) {
1271 skb->csum = skb_copy_and_csum_bits(skb_prev,
1272 maxfraglen,
1273 skb_transport_header(skb),
1274 fraggap, 0);
1275 skb_prev->csum = csum_sub(skb_prev->csum,
1276 skb->csum);
1277 pskb_trim_unique(skb_prev, maxfraglen);
1278 }
1279
1280 /*
1281 * Put the packet on the pending queue.
1282 */
1283 __skb_queue_tail(&sk->sk_write_queue, skb);
1284 continue;
1285 }
1286
1287 if (len > size)
1288 len = size;
1289
1290 if (skb_append_pagefrags(skb, page, offset, len)) {
1291 err = -EMSGSIZE;
1292 goto error;
1293 }
1294
1295 if (skb->ip_summed == CHECKSUM_NONE) {
1296 __wsum csum;
1297 csum = csum_page(page, offset, len);
1298 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1299 }
1300
1301 skb->len += len;
1302 skb->data_len += len;
1303 skb->truesize += len;
1304 refcount_add(len, &sk->sk_wmem_alloc);
1305 offset += len;
1306 size -= len;
1307 }
1308 return 0;
1309
1310error:
1311 cork->length -= size;
1312 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1313 return err;
1314}
1315
1316static void ip_cork_release(struct inet_cork *cork)
1317{
1318 cork->flags &= ~IPCORK_OPT;
1319 kfree(cork->opt);
1320 cork->opt = NULL;
1321 dst_release(cork->dst);
1322 cork->dst = NULL;
1323}
1324
1325/*
1326 * Combined all pending IP fragments on the socket as one IP datagram
1327 * and push them out.
1328 */
1329struct sk_buff *__ip_make_skb(struct sock *sk,
1330 struct flowi4 *fl4,
1331 struct sk_buff_head *queue,
1332 struct inet_cork *cork)
1333{
1334 struct sk_buff *skb, *tmp_skb;
1335 struct sk_buff **tail_skb;
1336 struct inet_sock *inet = inet_sk(sk);
1337 struct net *net = sock_net(sk);
1338 struct ip_options *opt = NULL;
1339 struct rtable *rt = (struct rtable *)cork->dst;
1340 struct iphdr *iph;
1341 __be16 df = 0;
1342 __u8 ttl;
1343
1344 skb = __skb_dequeue(queue);
1345 if (!skb)
1346 goto out;
1347 tail_skb = &(skb_shinfo(skb)->frag_list);
1348
1349 /* move skb->data to ip header from ext header */
1350 if (skb->data < skb_network_header(skb))
1351 __skb_pull(skb, skb_network_offset(skb));
1352 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1353 __skb_pull(tmp_skb, skb_network_header_len(skb));
1354 *tail_skb = tmp_skb;
1355 tail_skb = &(tmp_skb->next);
1356 skb->len += tmp_skb->len;
1357 skb->data_len += tmp_skb->len;
1358 skb->truesize += tmp_skb->truesize;
1359 tmp_skb->destructor = NULL;
1360 tmp_skb->sk = NULL;
1361 }
1362
1363 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1364 * to fragment the frame generated here. No matter, what transforms
1365 * how transforms change size of the packet, it will come out.
1366 */
1367 skb->ignore_df = ip_sk_ignore_df(sk);
1368
1369 /* DF bit is set when we want to see DF on outgoing frames.
1370 * If ignore_df is set too, we still allow to fragment this frame
1371 * locally. */
1372 if (inet->pmtudisc == IP_PMTUDISC_DO ||
1373 inet->pmtudisc == IP_PMTUDISC_PROBE ||
1374 (skb->len <= dst_mtu(&rt->dst) &&
1375 ip_dont_fragment(sk, &rt->dst)))
1376 df = htons(IP_DF);
1377
1378 if (cork->flags & IPCORK_OPT)
1379 opt = cork->opt;
1380
1381 if (cork->ttl != 0)
1382 ttl = cork->ttl;
1383 else if (rt->rt_type == RTN_MULTICAST)
1384 ttl = inet->mc_ttl;
1385 else
1386 ttl = ip_select_ttl(inet, &rt->dst);
1387
1388 iph = ip_hdr(skb);
1389 iph->version = 4;
1390 iph->ihl = 5;
1391 iph->tos = (cork->tos != -1) ? cork->tos : inet->tos;
1392 iph->frag_off = df;
1393 iph->ttl = ttl;
1394 iph->protocol = sk->sk_protocol;
1395 ip_copy_addrs(iph, fl4);
1396 ip_select_ident(net, skb, sk);
1397
1398 if (opt) {
1399 iph->ihl += opt->optlen>>2;
1400 ip_options_build(skb, opt, cork->addr, rt, 0);
1401 }
1402
1403 skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority;
1404 skb->mark = sk->sk_mark;
1405 /*
1406 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
1407 * on dst refcount
1408 */
1409 cork->dst = NULL;
1410 skb_dst_set(skb, &rt->dst);
1411
1412 if (iph->protocol == IPPROTO_ICMP)
1413 icmp_out_count(net, ((struct icmphdr *)
1414 skb_transport_header(skb))->type);
1415
1416 ip_cork_release(cork);
1417out:
1418 return skb;
1419}
1420
1421int ip_send_skb(struct net *net, struct sk_buff *skb)
1422{
1423 int err;
1424
1425 err = ip_local_out(net, skb->sk, skb);
1426 if (err) {
1427 if (err > 0)
1428 err = net_xmit_errno(err);
1429 if (err)
1430 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
1431 }
1432
1433 return err;
1434}
1435
1436int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4)
1437{
1438 struct sk_buff *skb;
1439
1440 skb = ip_finish_skb(sk, fl4);
1441 if (!skb)
1442 return 0;
1443
1444 /* Netfilter gets whole the not fragmented skb. */
1445 return ip_send_skb(sock_net(sk), skb);
1446}
1447
1448/*
1449 * Throw away all pending data on the socket.
1450 */
1451static void __ip_flush_pending_frames(struct sock *sk,
1452 struct sk_buff_head *queue,
1453 struct inet_cork *cork)
1454{
1455 struct sk_buff *skb;
1456
1457 while ((skb = __skb_dequeue_tail(queue)) != NULL)
1458 kfree_skb(skb);
1459
1460 ip_cork_release(cork);
1461}
1462
1463void ip_flush_pending_frames(struct sock *sk)
1464{
1465 __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
1466}
1467
1468struct sk_buff *ip_make_skb(struct sock *sk,
1469 struct flowi4 *fl4,
1470 int getfrag(void *from, char *to, int offset,
1471 int len, int odd, struct sk_buff *skb),
1472 void *from, int length, int transhdrlen,
1473 struct ipcm_cookie *ipc, struct rtable **rtp,
1474 unsigned int flags)
1475{
1476 struct inet_cork cork;
1477 struct sk_buff_head queue;
1478 int err;
1479
1480 if (flags & MSG_PROBE)
1481 return NULL;
1482
1483 __skb_queue_head_init(&queue);
1484
1485 cork.flags = 0;
1486 cork.addr = 0;
1487 cork.opt = NULL;
1488 err = ip_setup_cork(sk, &cork, ipc, rtp);
1489 if (err)
1490 return ERR_PTR(err);
1491
1492 err = __ip_append_data(sk, fl4, &queue, &cork,
1493 ¤t->task_frag, getfrag,
1494 from, length, transhdrlen, flags);
1495 if (err) {
1496 __ip_flush_pending_frames(sk, &queue, &cork);
1497 return ERR_PTR(err);
1498 }
1499
1500 return __ip_make_skb(sk, fl4, &queue, &cork);
1501}
1502
1503/*
1504 * Fetch data from kernel space and fill in checksum if needed.
1505 */
1506static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1507 int len, int odd, struct sk_buff *skb)
1508{
1509 __wsum csum;
1510
1511 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1512 skb->csum = csum_block_add(skb->csum, csum, odd);
1513 return 0;
1514}
1515
1516/*
1517 * Generic function to send a packet as reply to another packet.
1518 * Used to send some TCP resets/acks so far.
1519 */
1520void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
1521 const struct ip_options *sopt,
1522 __be32 daddr, __be32 saddr,
1523 const struct ip_reply_arg *arg,
1524 unsigned int len)
1525{
1526 struct ip_options_data replyopts;
1527 struct ipcm_cookie ipc;
1528 struct flowi4 fl4;
1529 struct rtable *rt = skb_rtable(skb);
1530 struct net *net = sock_net(sk);
1531 struct sk_buff *nskb;
1532 int err;
1533 int oif;
1534
1535 if (__ip_options_echo(net, &replyopts.opt.opt, skb, sopt))
1536 return;
1537
1538 ipc.addr = daddr;
1539 ipc.opt = NULL;
1540 ipc.tx_flags = 0;
1541 ipc.ttl = 0;
1542 ipc.tos = -1;
1543
1544 if (replyopts.opt.opt.optlen) {
1545 ipc.opt = &replyopts.opt;
1546
1547 if (replyopts.opt.opt.srr)
1548 daddr = replyopts.opt.opt.faddr;
1549 }
1550
1551 oif = arg->bound_dev_if;
1552 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
1553 oif = skb->skb_iif;
1554
1555 flowi4_init_output(&fl4, oif,
1556 IP4_REPLY_MARK(net, skb->mark),
1557 RT_TOS(arg->tos),
1558 RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
1559 ip_reply_arg_flowi_flags(arg),
1560 daddr, saddr,
1561 tcp_hdr(skb)->source, tcp_hdr(skb)->dest,
1562 arg->uid);
1563 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
1564 rt = ip_route_output_key(net, &fl4);
1565 if (IS_ERR(rt))
1566 return;
1567
1568 inet_sk(sk)->tos = arg->tos;
1569
1570 sk->sk_priority = skb->priority;
1571 sk->sk_protocol = ip_hdr(skb)->protocol;
1572 sk->sk_bound_dev_if = arg->bound_dev_if;
1573 sk->sk_sndbuf = sysctl_wmem_default;
1574 sk->sk_mark = fl4.flowi4_mark;
1575 err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base,
1576 len, 0, &ipc, &rt, MSG_DONTWAIT);
1577 if (unlikely(err)) {
1578 ip_flush_pending_frames(sk);
1579 goto out;
1580 }
1581
1582 nskb = skb_peek(&sk->sk_write_queue);
1583 if (nskb) {
1584 if (arg->csumoffset >= 0)
1585 *((__sum16 *)skb_transport_header(nskb) +
1586 arg->csumoffset) = csum_fold(csum_add(nskb->csum,
1587 arg->csum));
1588 nskb->ip_summed = CHECKSUM_NONE;
1589 ip_push_pending_frames(sk, &fl4);
1590 }
1591out:
1592 ip_rt_put(rt);
1593}
1594
1595void __init ip_init(void)
1596{
1597 ip_rt_init();
1598 inet_initpeers();
1599
1600#if defined(CONFIG_IP_MULTICAST)
1601 igmp_mc_init();
1602#endif
1603}
1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * The Internet Protocol (IP) output module.
7 *
8 * Authors: Ross Biro
9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 * Donald Becker, <becker@super.org>
11 * Alan Cox, <Alan.Cox@linux.org>
12 * Richard Underwood
13 * Stefan Becker, <stefanb@yello.ping.de>
14 * Jorge Cwik, <jorge@laser.satlink.net>
15 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
16 * Hirokazu Takahashi, <taka@valinux.co.jp>
17 *
18 * See ip_input.c for original log
19 *
20 * Fixes:
21 * Alan Cox : Missing nonblock feature in ip_build_xmit.
22 * Mike Kilburn : htons() missing in ip_build_xmit.
23 * Bradford Johnson: Fix faulty handling of some frames when
24 * no route is found.
25 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit
26 * (in case if packet not accepted by
27 * output firewall rules)
28 * Mike McLagan : Routing by source
29 * Alexey Kuznetsov: use new route cache
30 * Andi Kleen: Fix broken PMTU recovery and remove
31 * some redundant tests.
32 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
33 * Andi Kleen : Replace ip_reply with ip_send_reply.
34 * Andi Kleen : Split fast and slow ip_build_xmit path
35 * for decreased register pressure on x86
36 * and more readibility.
37 * Marc Boucher : When call_out_firewall returns FW_QUEUE,
38 * silently drop skb instead of failing with -EPERM.
39 * Detlev Wengorz : Copy protocol for fragments.
40 * Hirokazu Takahashi: HW checksumming for outgoing UDP
41 * datagrams.
42 * Hirokazu Takahashi: sendfile() on UDP works now.
43 */
44
45#include <asm/uaccess.h>
46#include <linux/module.h>
47#include <linux/types.h>
48#include <linux/kernel.h>
49#include <linux/mm.h>
50#include <linux/string.h>
51#include <linux/errno.h>
52#include <linux/highmem.h>
53#include <linux/slab.h>
54
55#include <linux/socket.h>
56#include <linux/sockios.h>
57#include <linux/in.h>
58#include <linux/inet.h>
59#include <linux/netdevice.h>
60#include <linux/etherdevice.h>
61#include <linux/proc_fs.h>
62#include <linux/stat.h>
63#include <linux/init.h>
64
65#include <net/snmp.h>
66#include <net/ip.h>
67#include <net/protocol.h>
68#include <net/route.h>
69#include <net/xfrm.h>
70#include <linux/skbuff.h>
71#include <net/sock.h>
72#include <net/arp.h>
73#include <net/icmp.h>
74#include <net/checksum.h>
75#include <net/inetpeer.h>
76#include <linux/igmp.h>
77#include <linux/netfilter_ipv4.h>
78#include <linux/netfilter_bridge.h>
79#include <linux/netlink.h>
80#include <linux/tcp.h>
81
82static int
83ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
84 unsigned int mtu,
85 int (*output)(struct net *, struct sock *, struct sk_buff *));
86
87/* Generate a checksum for an outgoing IP datagram. */
88void ip_send_check(struct iphdr *iph)
89{
90 iph->check = 0;
91 iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
92}
93EXPORT_SYMBOL(ip_send_check);
94
95int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
96{
97 struct iphdr *iph = ip_hdr(skb);
98
99 iph->tot_len = htons(skb->len);
100 ip_send_check(iph);
101 return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT,
102 net, sk, skb, NULL, skb_dst(skb)->dev,
103 dst_output);
104}
105
106int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
107{
108 int err;
109
110 err = __ip_local_out(net, sk, skb);
111 if (likely(err == 1))
112 err = dst_output(net, sk, skb);
113
114 return err;
115}
116EXPORT_SYMBOL_GPL(ip_local_out);
117
118static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
119{
120 int ttl = inet->uc_ttl;
121
122 if (ttl < 0)
123 ttl = ip4_dst_hoplimit(dst);
124 return ttl;
125}
126
127/*
128 * Add an ip header to a skbuff and send it out.
129 *
130 */
131int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
132 __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
133{
134 struct inet_sock *inet = inet_sk(sk);
135 struct rtable *rt = skb_rtable(skb);
136 struct net *net = sock_net(sk);
137 struct iphdr *iph;
138
139 /* Build the IP header. */
140 skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
141 skb_reset_network_header(skb);
142 iph = ip_hdr(skb);
143 iph->version = 4;
144 iph->ihl = 5;
145 iph->tos = inet->tos;
146 iph->ttl = ip_select_ttl(inet, &rt->dst);
147 iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
148 iph->saddr = saddr;
149 iph->protocol = sk->sk_protocol;
150 if (ip_dont_fragment(sk, &rt->dst)) {
151 iph->frag_off = htons(IP_DF);
152 iph->id = 0;
153 } else {
154 iph->frag_off = 0;
155 __ip_select_ident(net, iph, 1);
156 }
157
158 if (opt && opt->opt.optlen) {
159 iph->ihl += opt->opt.optlen>>2;
160 ip_options_build(skb, &opt->opt, daddr, rt, 0);
161 }
162
163 skb->priority = sk->sk_priority;
164 skb->mark = sk->sk_mark;
165
166 /* Send it out. */
167 return ip_local_out(net, skb->sk, skb);
168}
169EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
170
171static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
172{
173 struct dst_entry *dst = skb_dst(skb);
174 struct rtable *rt = (struct rtable *)dst;
175 struct net_device *dev = dst->dev;
176 unsigned int hh_len = LL_RESERVED_SPACE(dev);
177 struct neighbour *neigh;
178 u32 nexthop;
179
180 if (rt->rt_type == RTN_MULTICAST) {
181 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len);
182 } else if (rt->rt_type == RTN_BROADCAST)
183 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len);
184
185 /* Be paranoid, rather than too clever. */
186 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
187 struct sk_buff *skb2;
188
189 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
190 if (!skb2) {
191 kfree_skb(skb);
192 return -ENOMEM;
193 }
194 if (skb->sk)
195 skb_set_owner_w(skb2, skb->sk);
196 consume_skb(skb);
197 skb = skb2;
198 }
199
200 rcu_read_lock_bh();
201 nexthop = (__force u32) rt_nexthop(rt, ip_hdr(skb)->daddr);
202 neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
203 if (unlikely(!neigh))
204 neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
205 if (!IS_ERR(neigh)) {
206 int res = dst_neigh_output(dst, neigh, skb);
207
208 rcu_read_unlock_bh();
209 return res;
210 }
211 rcu_read_unlock_bh();
212
213 net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
214 __func__);
215 kfree_skb(skb);
216 return -EINVAL;
217}
218
219static int ip_finish_output_gso(struct net *net, struct sock *sk,
220 struct sk_buff *skb, unsigned int mtu)
221{
222 netdev_features_t features;
223 struct sk_buff *segs;
224 int ret = 0;
225
226 /* common case: locally created skb or seglen is <= mtu */
227 if (((IPCB(skb)->flags & IPSKB_FORWARDED) == 0) ||
228 skb_gso_network_seglen(skb) <= mtu)
229 return ip_finish_output2(net, sk, skb);
230
231 /* Slowpath - GSO segment length is exceeding the dst MTU.
232 *
233 * This can happen in two cases:
234 * 1) TCP GRO packet, DF bit not set
235 * 2) skb arrived via virtio-net, we thus get TSO/GSO skbs directly
236 * from host network stack.
237 */
238 features = netif_skb_features(skb);
239 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
240 segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
241 if (IS_ERR_OR_NULL(segs)) {
242 kfree_skb(skb);
243 return -ENOMEM;
244 }
245
246 consume_skb(skb);
247
248 do {
249 struct sk_buff *nskb = segs->next;
250 int err;
251
252 segs->next = NULL;
253 err = ip_fragment(net, sk, segs, mtu, ip_finish_output2);
254
255 if (err && ret == 0)
256 ret = err;
257 segs = nskb;
258 } while (segs);
259
260 return ret;
261}
262
263static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
264{
265 unsigned int mtu;
266
267#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
268 /* Policy lookup after SNAT yielded a new policy */
269 if (skb_dst(skb)->xfrm) {
270 IPCB(skb)->flags |= IPSKB_REROUTED;
271 return dst_output(net, sk, skb);
272 }
273#endif
274 mtu = ip_skb_dst_mtu(skb);
275 if (skb_is_gso(skb))
276 return ip_finish_output_gso(net, sk, skb, mtu);
277
278 if (skb->len > mtu || (IPCB(skb)->flags & IPSKB_FRAG_PMTU))
279 return ip_fragment(net, sk, skb, mtu, ip_finish_output2);
280
281 return ip_finish_output2(net, sk, skb);
282}
283
284int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb)
285{
286 struct rtable *rt = skb_rtable(skb);
287 struct net_device *dev = rt->dst.dev;
288
289 /*
290 * If the indicated interface is up and running, send the packet.
291 */
292 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
293
294 skb->dev = dev;
295 skb->protocol = htons(ETH_P_IP);
296
297 /*
298 * Multicasts are looped back for other local users
299 */
300
301 if (rt->rt_flags&RTCF_MULTICAST) {
302 if (sk_mc_loop(sk)
303#ifdef CONFIG_IP_MROUTE
304 /* Small optimization: do not loopback not local frames,
305 which returned after forwarding; they will be dropped
306 by ip_mr_input in any case.
307 Note, that local frames are looped back to be delivered
308 to local recipients.
309
310 This check is duplicated in ip_mr_input at the moment.
311 */
312 &&
313 ((rt->rt_flags & RTCF_LOCAL) ||
314 !(IPCB(skb)->flags & IPSKB_FORWARDED))
315#endif
316 ) {
317 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
318 if (newskb)
319 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
320 net, sk, newskb, NULL, newskb->dev,
321 dev_loopback_xmit);
322 }
323
324 /* Multicasts with ttl 0 must not go beyond the host */
325
326 if (ip_hdr(skb)->ttl == 0) {
327 kfree_skb(skb);
328 return 0;
329 }
330 }
331
332 if (rt->rt_flags&RTCF_BROADCAST) {
333 struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
334 if (newskb)
335 NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
336 net, sk, newskb, NULL, newskb->dev,
337 dev_loopback_xmit);
338 }
339
340 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
341 net, sk, skb, NULL, skb->dev,
342 ip_finish_output,
343 !(IPCB(skb)->flags & IPSKB_REROUTED));
344}
345
346int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb)
347{
348 struct net_device *dev = skb_dst(skb)->dev;
349
350 IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
351
352 skb->dev = dev;
353 skb->protocol = htons(ETH_P_IP);
354
355 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
356 net, sk, skb, NULL, dev,
357 ip_finish_output,
358 !(IPCB(skb)->flags & IPSKB_REROUTED));
359}
360
361/*
362 * copy saddr and daddr, possibly using 64bit load/stores
363 * Equivalent to :
364 * iph->saddr = fl4->saddr;
365 * iph->daddr = fl4->daddr;
366 */
367static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
368{
369 BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
370 offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
371 memcpy(&iph->saddr, &fl4->saddr,
372 sizeof(fl4->saddr) + sizeof(fl4->daddr));
373}
374
375/* Note: skb->sk can be different from sk, in case of tunnels */
376int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
377{
378 struct inet_sock *inet = inet_sk(sk);
379 struct net *net = sock_net(sk);
380 struct ip_options_rcu *inet_opt;
381 struct flowi4 *fl4;
382 struct rtable *rt;
383 struct iphdr *iph;
384 int res;
385
386 /* Skip all of this if the packet is already routed,
387 * f.e. by something like SCTP.
388 */
389 rcu_read_lock();
390 inet_opt = rcu_dereference(inet->inet_opt);
391 fl4 = &fl->u.ip4;
392 rt = skb_rtable(skb);
393 if (rt)
394 goto packet_routed;
395
396 /* Make sure we can route this packet. */
397 rt = (struct rtable *)__sk_dst_check(sk, 0);
398 if (!rt) {
399 __be32 daddr;
400
401 /* Use correct destination address if we have options. */
402 daddr = inet->inet_daddr;
403 if (inet_opt && inet_opt->opt.srr)
404 daddr = inet_opt->opt.faddr;
405
406 /* If this fails, retransmit mechanism of transport layer will
407 * keep trying until route appears or the connection times
408 * itself out.
409 */
410 rt = ip_route_output_ports(net, fl4, sk,
411 daddr, inet->inet_saddr,
412 inet->inet_dport,
413 inet->inet_sport,
414 sk->sk_protocol,
415 RT_CONN_FLAGS(sk),
416 sk->sk_bound_dev_if);
417 if (IS_ERR(rt))
418 goto no_route;
419 sk_setup_caps(sk, &rt->dst);
420 }
421 skb_dst_set_noref(skb, &rt->dst);
422
423packet_routed:
424 if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
425 goto no_route;
426
427 /* OK, we know where to send it, allocate and build IP header. */
428 skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
429 skb_reset_network_header(skb);
430 iph = ip_hdr(skb);
431 *((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff));
432 if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df)
433 iph->frag_off = htons(IP_DF);
434 else
435 iph->frag_off = 0;
436 iph->ttl = ip_select_ttl(inet, &rt->dst);
437 iph->protocol = sk->sk_protocol;
438 ip_copy_addrs(iph, fl4);
439
440 /* Transport layer set skb->h.foo itself. */
441
442 if (inet_opt && inet_opt->opt.optlen) {
443 iph->ihl += inet_opt->opt.optlen >> 2;
444 ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
445 }
446
447 ip_select_ident_segs(net, skb, sk,
448 skb_shinfo(skb)->gso_segs ?: 1);
449
450 /* TODO : should we use skb->sk here instead of sk ? */
451 skb->priority = sk->sk_priority;
452 skb->mark = sk->sk_mark;
453
454 res = ip_local_out(net, sk, skb);
455 rcu_read_unlock();
456 return res;
457
458no_route:
459 rcu_read_unlock();
460 IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
461 kfree_skb(skb);
462 return -EHOSTUNREACH;
463}
464EXPORT_SYMBOL(ip_queue_xmit);
465
466static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
467{
468 to->pkt_type = from->pkt_type;
469 to->priority = from->priority;
470 to->protocol = from->protocol;
471 skb_dst_drop(to);
472 skb_dst_copy(to, from);
473 to->dev = from->dev;
474 to->mark = from->mark;
475
476 /* Copy the flags to each fragment. */
477 IPCB(to)->flags = IPCB(from)->flags;
478
479#ifdef CONFIG_NET_SCHED
480 to->tc_index = from->tc_index;
481#endif
482 nf_copy(to, from);
483#if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
484 to->ipvs_property = from->ipvs_property;
485#endif
486 skb_copy_secmark(to, from);
487}
488
489static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
490 unsigned int mtu,
491 int (*output)(struct net *, struct sock *, struct sk_buff *))
492{
493 struct iphdr *iph = ip_hdr(skb);
494
495 if ((iph->frag_off & htons(IP_DF)) == 0)
496 return ip_do_fragment(net, sk, skb, output);
497
498 if (unlikely(!skb->ignore_df ||
499 (IPCB(skb)->frag_max_size &&
500 IPCB(skb)->frag_max_size > mtu))) {
501 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
502 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
503 htonl(mtu));
504 kfree_skb(skb);
505 return -EMSGSIZE;
506 }
507
508 return ip_do_fragment(net, sk, skb, output);
509}
510
511/*
512 * This IP datagram is too large to be sent in one piece. Break it up into
513 * smaller pieces (each of size equal to IP header plus
514 * a block of the data of the original IP data part) that will yet fit in a
515 * single device frame, and queue such a frame for sending.
516 */
517
518int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
519 int (*output)(struct net *, struct sock *, struct sk_buff *))
520{
521 struct iphdr *iph;
522 int ptr;
523 struct net_device *dev;
524 struct sk_buff *skb2;
525 unsigned int mtu, hlen, left, len, ll_rs;
526 int offset;
527 __be16 not_last_frag;
528 struct rtable *rt = skb_rtable(skb);
529 int err = 0;
530
531 dev = rt->dst.dev;
532
533 /* for offloaded checksums cleanup checksum before fragmentation */
534 if (skb->ip_summed == CHECKSUM_PARTIAL &&
535 (err = skb_checksum_help(skb)))
536 goto fail;
537
538 /*
539 * Point into the IP datagram header.
540 */
541
542 iph = ip_hdr(skb);
543
544 mtu = ip_skb_dst_mtu(skb);
545 if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu)
546 mtu = IPCB(skb)->frag_max_size;
547
548 /*
549 * Setup starting values.
550 */
551
552 hlen = iph->ihl * 4;
553 mtu = mtu - hlen; /* Size of data space */
554 IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
555
556 /* When frag_list is given, use it. First, check its validity:
557 * some transformers could create wrong frag_list or break existing
558 * one, it is not prohibited. In this case fall back to copying.
559 *
560 * LATER: this step can be merged to real generation of fragments,
561 * we can switch to copy when see the first bad fragment.
562 */
563 if (skb_has_frag_list(skb)) {
564 struct sk_buff *frag, *frag2;
565 int first_len = skb_pagelen(skb);
566
567 if (first_len - hlen > mtu ||
568 ((first_len - hlen) & 7) ||
569 ip_is_fragment(iph) ||
570 skb_cloned(skb))
571 goto slow_path;
572
573 skb_walk_frags(skb, frag) {
574 /* Correct geometry. */
575 if (frag->len > mtu ||
576 ((frag->len & 7) && frag->next) ||
577 skb_headroom(frag) < hlen)
578 goto slow_path_clean;
579
580 /* Partially cloned skb? */
581 if (skb_shared(frag))
582 goto slow_path_clean;
583
584 BUG_ON(frag->sk);
585 if (skb->sk) {
586 frag->sk = skb->sk;
587 frag->destructor = sock_wfree;
588 }
589 skb->truesize -= frag->truesize;
590 }
591
592 /* Everything is OK. Generate! */
593
594 err = 0;
595 offset = 0;
596 frag = skb_shinfo(skb)->frag_list;
597 skb_frag_list_init(skb);
598 skb->data_len = first_len - skb_headlen(skb);
599 skb->len = first_len;
600 iph->tot_len = htons(first_len);
601 iph->frag_off = htons(IP_MF);
602 ip_send_check(iph);
603
604 for (;;) {
605 /* Prepare header of the next frame,
606 * before previous one went down. */
607 if (frag) {
608 frag->ip_summed = CHECKSUM_NONE;
609 skb_reset_transport_header(frag);
610 __skb_push(frag, hlen);
611 skb_reset_network_header(frag);
612 memcpy(skb_network_header(frag), iph, hlen);
613 iph = ip_hdr(frag);
614 iph->tot_len = htons(frag->len);
615 ip_copy_metadata(frag, skb);
616 if (offset == 0)
617 ip_options_fragment(frag);
618 offset += skb->len - hlen;
619 iph->frag_off = htons(offset>>3);
620 if (frag->next)
621 iph->frag_off |= htons(IP_MF);
622 /* Ready, complete checksum */
623 ip_send_check(iph);
624 }
625
626 err = output(net, sk, skb);
627
628 if (!err)
629 IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
630 if (err || !frag)
631 break;
632
633 skb = frag;
634 frag = skb->next;
635 skb->next = NULL;
636 }
637
638 if (err == 0) {
639 IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS);
640 return 0;
641 }
642
643 while (frag) {
644 skb = frag->next;
645 kfree_skb(frag);
646 frag = skb;
647 }
648 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
649 return err;
650
651slow_path_clean:
652 skb_walk_frags(skb, frag2) {
653 if (frag2 == frag)
654 break;
655 frag2->sk = NULL;
656 frag2->destructor = NULL;
657 skb->truesize += frag2->truesize;
658 }
659 }
660
661slow_path:
662 iph = ip_hdr(skb);
663
664 left = skb->len - hlen; /* Space per frame */
665 ptr = hlen; /* Where to start from */
666
667 ll_rs = LL_RESERVED_SPACE(rt->dst.dev);
668
669 /*
670 * Fragment the datagram.
671 */
672
673 offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
674 not_last_frag = iph->frag_off & htons(IP_MF);
675
676 /*
677 * Keep copying data until we run out.
678 */
679
680 while (left > 0) {
681 len = left;
682 /* IF: it doesn't fit, use 'mtu' - the data space left */
683 if (len > mtu)
684 len = mtu;
685 /* IF: we are not sending up to and including the packet end
686 then align the next start on an eight byte boundary */
687 if (len < left) {
688 len &= ~7;
689 }
690
691 /* Allocate buffer */
692 skb2 = alloc_skb(len + hlen + ll_rs, GFP_ATOMIC);
693 if (!skb2) {
694 err = -ENOMEM;
695 goto fail;
696 }
697
698 /*
699 * Set up data on packet
700 */
701
702 ip_copy_metadata(skb2, skb);
703 skb_reserve(skb2, ll_rs);
704 skb_put(skb2, len + hlen);
705 skb_reset_network_header(skb2);
706 skb2->transport_header = skb2->network_header + hlen;
707
708 /*
709 * Charge the memory for the fragment to any owner
710 * it might possess
711 */
712
713 if (skb->sk)
714 skb_set_owner_w(skb2, skb->sk);
715
716 /*
717 * Copy the packet header into the new buffer.
718 */
719
720 skb_copy_from_linear_data(skb, skb_network_header(skb2), hlen);
721
722 /*
723 * Copy a block of the IP datagram.
724 */
725 if (skb_copy_bits(skb, ptr, skb_transport_header(skb2), len))
726 BUG();
727 left -= len;
728
729 /*
730 * Fill in the new header fields.
731 */
732 iph = ip_hdr(skb2);
733 iph->frag_off = htons((offset >> 3));
734
735 if (IPCB(skb)->flags & IPSKB_FRAG_PMTU)
736 iph->frag_off |= htons(IP_DF);
737
738 /* ANK: dirty, but effective trick. Upgrade options only if
739 * the segment to be fragmented was THE FIRST (otherwise,
740 * options are already fixed) and make it ONCE
741 * on the initial skb, so that all the following fragments
742 * will inherit fixed options.
743 */
744 if (offset == 0)
745 ip_options_fragment(skb);
746
747 /*
748 * Added AC : If we are fragmenting a fragment that's not the
749 * last fragment then keep MF on each bit
750 */
751 if (left > 0 || not_last_frag)
752 iph->frag_off |= htons(IP_MF);
753 ptr += len;
754 offset += len;
755
756 /*
757 * Put this fragment into the sending queue.
758 */
759 iph->tot_len = htons(len + hlen);
760
761 ip_send_check(iph);
762
763 err = output(net, sk, skb2);
764 if (err)
765 goto fail;
766
767 IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
768 }
769 consume_skb(skb);
770 IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS);
771 return err;
772
773fail:
774 kfree_skb(skb);
775 IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
776 return err;
777}
778EXPORT_SYMBOL(ip_do_fragment);
779
780int
781ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
782{
783 struct msghdr *msg = from;
784
785 if (skb->ip_summed == CHECKSUM_PARTIAL) {
786 if (copy_from_iter(to, len, &msg->msg_iter) != len)
787 return -EFAULT;
788 } else {
789 __wsum csum = 0;
790 if (csum_and_copy_from_iter(to, len, &csum, &msg->msg_iter) != len)
791 return -EFAULT;
792 skb->csum = csum_block_add(skb->csum, csum, odd);
793 }
794 return 0;
795}
796EXPORT_SYMBOL(ip_generic_getfrag);
797
798static inline __wsum
799csum_page(struct page *page, int offset, int copy)
800{
801 char *kaddr;
802 __wsum csum;
803 kaddr = kmap(page);
804 csum = csum_partial(kaddr + offset, copy, 0);
805 kunmap(page);
806 return csum;
807}
808
809static inline int ip_ufo_append_data(struct sock *sk,
810 struct sk_buff_head *queue,
811 int getfrag(void *from, char *to, int offset, int len,
812 int odd, struct sk_buff *skb),
813 void *from, int length, int hh_len, int fragheaderlen,
814 int transhdrlen, int maxfraglen, unsigned int flags)
815{
816 struct sk_buff *skb;
817 int err;
818
819 /* There is support for UDP fragmentation offload by network
820 * device, so create one single skb packet containing complete
821 * udp datagram
822 */
823 skb = skb_peek_tail(queue);
824 if (!skb) {
825 skb = sock_alloc_send_skb(sk,
826 hh_len + fragheaderlen + transhdrlen + 20,
827 (flags & MSG_DONTWAIT), &err);
828
829 if (!skb)
830 return err;
831
832 /* reserve space for Hardware header */
833 skb_reserve(skb, hh_len);
834
835 /* create space for UDP/IP header */
836 skb_put(skb, fragheaderlen + transhdrlen);
837
838 /* initialize network header pointer */
839 skb_reset_network_header(skb);
840
841 /* initialize protocol header pointer */
842 skb->transport_header = skb->network_header + fragheaderlen;
843
844 skb->csum = 0;
845
846 __skb_queue_tail(queue, skb);
847 } else if (skb_is_gso(skb)) {
848 goto append;
849 }
850
851 skb->ip_summed = CHECKSUM_PARTIAL;
852 /* specify the length of each IP datagram fragment */
853 skb_shinfo(skb)->gso_size = maxfraglen - fragheaderlen;
854 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
855
856append:
857 return skb_append_datato_frags(sk, skb, getfrag, from,
858 (length - transhdrlen));
859}
860
861static int __ip_append_data(struct sock *sk,
862 struct flowi4 *fl4,
863 struct sk_buff_head *queue,
864 struct inet_cork *cork,
865 struct page_frag *pfrag,
866 int getfrag(void *from, char *to, int offset,
867 int len, int odd, struct sk_buff *skb),
868 void *from, int length, int transhdrlen,
869 unsigned int flags)
870{
871 struct inet_sock *inet = inet_sk(sk);
872 struct sk_buff *skb;
873
874 struct ip_options *opt = cork->opt;
875 int hh_len;
876 int exthdrlen;
877 int mtu;
878 int copy;
879 int err;
880 int offset = 0;
881 unsigned int maxfraglen, fragheaderlen, maxnonfragsize;
882 int csummode = CHECKSUM_NONE;
883 struct rtable *rt = (struct rtable *)cork->dst;
884 u32 tskey = 0;
885
886 skb = skb_peek_tail(queue);
887
888 exthdrlen = !skb ? rt->dst.header_len : 0;
889 mtu = cork->fragsize;
890 if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP &&
891 sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
892 tskey = sk->sk_tskey++;
893
894 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
895
896 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
897 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
898 maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu;
899
900 if (cork->length + length > maxnonfragsize - fragheaderlen) {
901 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
902 mtu - (opt ? opt->optlen : 0));
903 return -EMSGSIZE;
904 }
905
906 /*
907 * transhdrlen > 0 means that this is the first fragment and we wish
908 * it won't be fragmented in the future.
909 */
910 if (transhdrlen &&
911 length + fragheaderlen <= mtu &&
912 rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) &&
913 !(flags & MSG_MORE) &&
914 !exthdrlen)
915 csummode = CHECKSUM_PARTIAL;
916
917 cork->length += length;
918 if (((length > mtu) || (skb && skb_is_gso(skb))) &&
919 (sk->sk_protocol == IPPROTO_UDP) &&
920 (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len &&
921 (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx) {
922 err = ip_ufo_append_data(sk, queue, getfrag, from, length,
923 hh_len, fragheaderlen, transhdrlen,
924 maxfraglen, flags);
925 if (err)
926 goto error;
927 return 0;
928 }
929
930 /* So, what's going on in the loop below?
931 *
932 * We use calculated fragment length to generate chained skb,
933 * each of segments is IP fragment ready for sending to network after
934 * adding appropriate IP header.
935 */
936
937 if (!skb)
938 goto alloc_new_skb;
939
940 while (length > 0) {
941 /* Check if the remaining data fits into current packet. */
942 copy = mtu - skb->len;
943 if (copy < length)
944 copy = maxfraglen - skb->len;
945 if (copy <= 0) {
946 char *data;
947 unsigned int datalen;
948 unsigned int fraglen;
949 unsigned int fraggap;
950 unsigned int alloclen;
951 struct sk_buff *skb_prev;
952alloc_new_skb:
953 skb_prev = skb;
954 if (skb_prev)
955 fraggap = skb_prev->len - maxfraglen;
956 else
957 fraggap = 0;
958
959 /*
960 * If remaining data exceeds the mtu,
961 * we know we need more fragment(s).
962 */
963 datalen = length + fraggap;
964 if (datalen > mtu - fragheaderlen)
965 datalen = maxfraglen - fragheaderlen;
966 fraglen = datalen + fragheaderlen;
967
968 if ((flags & MSG_MORE) &&
969 !(rt->dst.dev->features&NETIF_F_SG))
970 alloclen = mtu;
971 else
972 alloclen = fraglen;
973
974 alloclen += exthdrlen;
975
976 /* The last fragment gets additional space at tail.
977 * Note, with MSG_MORE we overallocate on fragments,
978 * because we have no idea what fragment will be
979 * the last.
980 */
981 if (datalen == length + fraggap)
982 alloclen += rt->dst.trailer_len;
983
984 if (transhdrlen) {
985 skb = sock_alloc_send_skb(sk,
986 alloclen + hh_len + 15,
987 (flags & MSG_DONTWAIT), &err);
988 } else {
989 skb = NULL;
990 if (atomic_read(&sk->sk_wmem_alloc) <=
991 2 * sk->sk_sndbuf)
992 skb = sock_wmalloc(sk,
993 alloclen + hh_len + 15, 1,
994 sk->sk_allocation);
995 if (unlikely(!skb))
996 err = -ENOBUFS;
997 }
998 if (!skb)
999 goto error;
1000
1001 /*
1002 * Fill in the control structures
1003 */
1004 skb->ip_summed = csummode;
1005 skb->csum = 0;
1006 skb_reserve(skb, hh_len);
1007
1008 /* only the initial fragment is time stamped */
1009 skb_shinfo(skb)->tx_flags = cork->tx_flags;
1010 cork->tx_flags = 0;
1011 skb_shinfo(skb)->tskey = tskey;
1012 tskey = 0;
1013
1014 /*
1015 * Find where to start putting bytes.
1016 */
1017 data = skb_put(skb, fraglen + exthdrlen);
1018 skb_set_network_header(skb, exthdrlen);
1019 skb->transport_header = (skb->network_header +
1020 fragheaderlen);
1021 data += fragheaderlen + exthdrlen;
1022
1023 if (fraggap) {
1024 skb->csum = skb_copy_and_csum_bits(
1025 skb_prev, maxfraglen,
1026 data + transhdrlen, fraggap, 0);
1027 skb_prev->csum = csum_sub(skb_prev->csum,
1028 skb->csum);
1029 data += fraggap;
1030 pskb_trim_unique(skb_prev, maxfraglen);
1031 }
1032
1033 copy = datalen - transhdrlen - fraggap;
1034 if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
1035 err = -EFAULT;
1036 kfree_skb(skb);
1037 goto error;
1038 }
1039
1040 offset += copy;
1041 length -= datalen - fraggap;
1042 transhdrlen = 0;
1043 exthdrlen = 0;
1044 csummode = CHECKSUM_NONE;
1045
1046 /*
1047 * Put the packet on the pending queue.
1048 */
1049 __skb_queue_tail(queue, skb);
1050 continue;
1051 }
1052
1053 if (copy > length)
1054 copy = length;
1055
1056 if (!(rt->dst.dev->features&NETIF_F_SG)) {
1057 unsigned int off;
1058
1059 off = skb->len;
1060 if (getfrag(from, skb_put(skb, copy),
1061 offset, copy, off, skb) < 0) {
1062 __skb_trim(skb, off);
1063 err = -EFAULT;
1064 goto error;
1065 }
1066 } else {
1067 int i = skb_shinfo(skb)->nr_frags;
1068
1069 err = -ENOMEM;
1070 if (!sk_page_frag_refill(sk, pfrag))
1071 goto error;
1072
1073 if (!skb_can_coalesce(skb, i, pfrag->page,
1074 pfrag->offset)) {
1075 err = -EMSGSIZE;
1076 if (i == MAX_SKB_FRAGS)
1077 goto error;
1078
1079 __skb_fill_page_desc(skb, i, pfrag->page,
1080 pfrag->offset, 0);
1081 skb_shinfo(skb)->nr_frags = ++i;
1082 get_page(pfrag->page);
1083 }
1084 copy = min_t(int, copy, pfrag->size - pfrag->offset);
1085 if (getfrag(from,
1086 page_address(pfrag->page) + pfrag->offset,
1087 offset, copy, skb->len, skb) < 0)
1088 goto error_efault;
1089
1090 pfrag->offset += copy;
1091 skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
1092 skb->len += copy;
1093 skb->data_len += copy;
1094 skb->truesize += copy;
1095 atomic_add(copy, &sk->sk_wmem_alloc);
1096 }
1097 offset += copy;
1098 length -= copy;
1099 }
1100
1101 return 0;
1102
1103error_efault:
1104 err = -EFAULT;
1105error:
1106 cork->length -= length;
1107 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1108 return err;
1109}
1110
1111static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
1112 struct ipcm_cookie *ipc, struct rtable **rtp)
1113{
1114 struct ip_options_rcu *opt;
1115 struct rtable *rt;
1116
1117 /*
1118 * setup for corking.
1119 */
1120 opt = ipc->opt;
1121 if (opt) {
1122 if (!cork->opt) {
1123 cork->opt = kmalloc(sizeof(struct ip_options) + 40,
1124 sk->sk_allocation);
1125 if (unlikely(!cork->opt))
1126 return -ENOBUFS;
1127 }
1128 memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
1129 cork->flags |= IPCORK_OPT;
1130 cork->addr = ipc->addr;
1131 }
1132 rt = *rtp;
1133 if (unlikely(!rt))
1134 return -EFAULT;
1135 /*
1136 * We steal reference to this route, caller should not release it
1137 */
1138 *rtp = NULL;
1139 cork->fragsize = ip_sk_use_pmtu(sk) ?
1140 dst_mtu(&rt->dst) : rt->dst.dev->mtu;
1141 cork->dst = &rt->dst;
1142 cork->length = 0;
1143 cork->ttl = ipc->ttl;
1144 cork->tos = ipc->tos;
1145 cork->priority = ipc->priority;
1146 cork->tx_flags = ipc->tx_flags;
1147
1148 return 0;
1149}
1150
1151/*
1152 * ip_append_data() and ip_append_page() can make one large IP datagram
1153 * from many pieces of data. Each pieces will be holded on the socket
1154 * until ip_push_pending_frames() is called. Each piece can be a page
1155 * or non-page data.
1156 *
1157 * Not only UDP, other transport protocols - e.g. raw sockets - can use
1158 * this interface potentially.
1159 *
1160 * LATER: length must be adjusted by pad at tail, when it is required.
1161 */
1162int ip_append_data(struct sock *sk, struct flowi4 *fl4,
1163 int getfrag(void *from, char *to, int offset, int len,
1164 int odd, struct sk_buff *skb),
1165 void *from, int length, int transhdrlen,
1166 struct ipcm_cookie *ipc, struct rtable **rtp,
1167 unsigned int flags)
1168{
1169 struct inet_sock *inet = inet_sk(sk);
1170 int err;
1171
1172 if (flags&MSG_PROBE)
1173 return 0;
1174
1175 if (skb_queue_empty(&sk->sk_write_queue)) {
1176 err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
1177 if (err)
1178 return err;
1179 } else {
1180 transhdrlen = 0;
1181 }
1182
1183 return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base,
1184 sk_page_frag(sk), getfrag,
1185 from, length, transhdrlen, flags);
1186}
1187
1188ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
1189 int offset, size_t size, int flags)
1190{
1191 struct inet_sock *inet = inet_sk(sk);
1192 struct sk_buff *skb;
1193 struct rtable *rt;
1194 struct ip_options *opt = NULL;
1195 struct inet_cork *cork;
1196 int hh_len;
1197 int mtu;
1198 int len;
1199 int err;
1200 unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize;
1201
1202 if (inet->hdrincl)
1203 return -EPERM;
1204
1205 if (flags&MSG_PROBE)
1206 return 0;
1207
1208 if (skb_queue_empty(&sk->sk_write_queue))
1209 return -EINVAL;
1210
1211 cork = &inet->cork.base;
1212 rt = (struct rtable *)cork->dst;
1213 if (cork->flags & IPCORK_OPT)
1214 opt = cork->opt;
1215
1216 if (!(rt->dst.dev->features&NETIF_F_SG))
1217 return -EOPNOTSUPP;
1218
1219 hh_len = LL_RESERVED_SPACE(rt->dst.dev);
1220 mtu = cork->fragsize;
1221
1222 fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
1223 maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
1224 maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu;
1225
1226 if (cork->length + size > maxnonfragsize - fragheaderlen) {
1227 ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
1228 mtu - (opt ? opt->optlen : 0));
1229 return -EMSGSIZE;
1230 }
1231
1232 skb = skb_peek_tail(&sk->sk_write_queue);
1233 if (!skb)
1234 return -EINVAL;
1235
1236 if ((size + skb->len > mtu) &&
1237 (sk->sk_protocol == IPPROTO_UDP) &&
1238 (rt->dst.dev->features & NETIF_F_UFO)) {
1239 if (skb->ip_summed != CHECKSUM_PARTIAL)
1240 return -EOPNOTSUPP;
1241
1242 skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
1243 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
1244 }
1245 cork->length += size;
1246
1247 while (size > 0) {
1248 if (skb_is_gso(skb)) {
1249 len = size;
1250 } else {
1251
1252 /* Check if the remaining data fits into current packet. */
1253 len = mtu - skb->len;
1254 if (len < size)
1255 len = maxfraglen - skb->len;
1256 }
1257 if (len <= 0) {
1258 struct sk_buff *skb_prev;
1259 int alloclen;
1260
1261 skb_prev = skb;
1262 fraggap = skb_prev->len - maxfraglen;
1263
1264 alloclen = fragheaderlen + hh_len + fraggap + 15;
1265 skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
1266 if (unlikely(!skb)) {
1267 err = -ENOBUFS;
1268 goto error;
1269 }
1270
1271 /*
1272 * Fill in the control structures
1273 */
1274 skb->ip_summed = CHECKSUM_NONE;
1275 skb->csum = 0;
1276 skb_reserve(skb, hh_len);
1277
1278 /*
1279 * Find where to start putting bytes.
1280 */
1281 skb_put(skb, fragheaderlen + fraggap);
1282 skb_reset_network_header(skb);
1283 skb->transport_header = (skb->network_header +
1284 fragheaderlen);
1285 if (fraggap) {
1286 skb->csum = skb_copy_and_csum_bits(skb_prev,
1287 maxfraglen,
1288 skb_transport_header(skb),
1289 fraggap, 0);
1290 skb_prev->csum = csum_sub(skb_prev->csum,
1291 skb->csum);
1292 pskb_trim_unique(skb_prev, maxfraglen);
1293 }
1294
1295 /*
1296 * Put the packet on the pending queue.
1297 */
1298 __skb_queue_tail(&sk->sk_write_queue, skb);
1299 continue;
1300 }
1301
1302 if (len > size)
1303 len = size;
1304
1305 if (skb_append_pagefrags(skb, page, offset, len)) {
1306 err = -EMSGSIZE;
1307 goto error;
1308 }
1309
1310 if (skb->ip_summed == CHECKSUM_NONE) {
1311 __wsum csum;
1312 csum = csum_page(page, offset, len);
1313 skb->csum = csum_block_add(skb->csum, csum, skb->len);
1314 }
1315
1316 skb->len += len;
1317 skb->data_len += len;
1318 skb->truesize += len;
1319 atomic_add(len, &sk->sk_wmem_alloc);
1320 offset += len;
1321 size -= len;
1322 }
1323 return 0;
1324
1325error:
1326 cork->length -= size;
1327 IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
1328 return err;
1329}
1330
1331static void ip_cork_release(struct inet_cork *cork)
1332{
1333 cork->flags &= ~IPCORK_OPT;
1334 kfree(cork->opt);
1335 cork->opt = NULL;
1336 dst_release(cork->dst);
1337 cork->dst = NULL;
1338}
1339
1340/*
1341 * Combined all pending IP fragments on the socket as one IP datagram
1342 * and push them out.
1343 */
1344struct sk_buff *__ip_make_skb(struct sock *sk,
1345 struct flowi4 *fl4,
1346 struct sk_buff_head *queue,
1347 struct inet_cork *cork)
1348{
1349 struct sk_buff *skb, *tmp_skb;
1350 struct sk_buff **tail_skb;
1351 struct inet_sock *inet = inet_sk(sk);
1352 struct net *net = sock_net(sk);
1353 struct ip_options *opt = NULL;
1354 struct rtable *rt = (struct rtable *)cork->dst;
1355 struct iphdr *iph;
1356 __be16 df = 0;
1357 __u8 ttl;
1358
1359 skb = __skb_dequeue(queue);
1360 if (!skb)
1361 goto out;
1362 tail_skb = &(skb_shinfo(skb)->frag_list);
1363
1364 /* move skb->data to ip header from ext header */
1365 if (skb->data < skb_network_header(skb))
1366 __skb_pull(skb, skb_network_offset(skb));
1367 while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
1368 __skb_pull(tmp_skb, skb_network_header_len(skb));
1369 *tail_skb = tmp_skb;
1370 tail_skb = &(tmp_skb->next);
1371 skb->len += tmp_skb->len;
1372 skb->data_len += tmp_skb->len;
1373 skb->truesize += tmp_skb->truesize;
1374 tmp_skb->destructor = NULL;
1375 tmp_skb->sk = NULL;
1376 }
1377
1378 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1379 * to fragment the frame generated here. No matter, what transforms
1380 * how transforms change size of the packet, it will come out.
1381 */
1382 skb->ignore_df = ip_sk_ignore_df(sk);
1383
1384 /* DF bit is set when we want to see DF on outgoing frames.
1385 * If ignore_df is set too, we still allow to fragment this frame
1386 * locally. */
1387 if (inet->pmtudisc == IP_PMTUDISC_DO ||
1388 inet->pmtudisc == IP_PMTUDISC_PROBE ||
1389 (skb->len <= dst_mtu(&rt->dst) &&
1390 ip_dont_fragment(sk, &rt->dst)))
1391 df = htons(IP_DF);
1392
1393 if (cork->flags & IPCORK_OPT)
1394 opt = cork->opt;
1395
1396 if (cork->ttl != 0)
1397 ttl = cork->ttl;
1398 else if (rt->rt_type == RTN_MULTICAST)
1399 ttl = inet->mc_ttl;
1400 else
1401 ttl = ip_select_ttl(inet, &rt->dst);
1402
1403 iph = ip_hdr(skb);
1404 iph->version = 4;
1405 iph->ihl = 5;
1406 iph->tos = (cork->tos != -1) ? cork->tos : inet->tos;
1407 iph->frag_off = df;
1408 iph->ttl = ttl;
1409 iph->protocol = sk->sk_protocol;
1410 ip_copy_addrs(iph, fl4);
1411 ip_select_ident(net, skb, sk);
1412
1413 if (opt) {
1414 iph->ihl += opt->optlen>>2;
1415 ip_options_build(skb, opt, cork->addr, rt, 0);
1416 }
1417
1418 skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority;
1419 skb->mark = sk->sk_mark;
1420 /*
1421 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
1422 * on dst refcount
1423 */
1424 cork->dst = NULL;
1425 skb_dst_set(skb, &rt->dst);
1426
1427 if (iph->protocol == IPPROTO_ICMP)
1428 icmp_out_count(net, ((struct icmphdr *)
1429 skb_transport_header(skb))->type);
1430
1431 ip_cork_release(cork);
1432out:
1433 return skb;
1434}
1435
1436int ip_send_skb(struct net *net, struct sk_buff *skb)
1437{
1438 int err;
1439
1440 err = ip_local_out(net, skb->sk, skb);
1441 if (err) {
1442 if (err > 0)
1443 err = net_xmit_errno(err);
1444 if (err)
1445 IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
1446 }
1447
1448 return err;
1449}
1450
1451int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4)
1452{
1453 struct sk_buff *skb;
1454
1455 skb = ip_finish_skb(sk, fl4);
1456 if (!skb)
1457 return 0;
1458
1459 /* Netfilter gets whole the not fragmented skb. */
1460 return ip_send_skb(sock_net(sk), skb);
1461}
1462
1463/*
1464 * Throw away all pending data on the socket.
1465 */
1466static void __ip_flush_pending_frames(struct sock *sk,
1467 struct sk_buff_head *queue,
1468 struct inet_cork *cork)
1469{
1470 struct sk_buff *skb;
1471
1472 while ((skb = __skb_dequeue_tail(queue)) != NULL)
1473 kfree_skb(skb);
1474
1475 ip_cork_release(cork);
1476}
1477
1478void ip_flush_pending_frames(struct sock *sk)
1479{
1480 __ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
1481}
1482
1483struct sk_buff *ip_make_skb(struct sock *sk,
1484 struct flowi4 *fl4,
1485 int getfrag(void *from, char *to, int offset,
1486 int len, int odd, struct sk_buff *skb),
1487 void *from, int length, int transhdrlen,
1488 struct ipcm_cookie *ipc, struct rtable **rtp,
1489 unsigned int flags)
1490{
1491 struct inet_cork cork;
1492 struct sk_buff_head queue;
1493 int err;
1494
1495 if (flags & MSG_PROBE)
1496 return NULL;
1497
1498 __skb_queue_head_init(&queue);
1499
1500 cork.flags = 0;
1501 cork.addr = 0;
1502 cork.opt = NULL;
1503 err = ip_setup_cork(sk, &cork, ipc, rtp);
1504 if (err)
1505 return ERR_PTR(err);
1506
1507 err = __ip_append_data(sk, fl4, &queue, &cork,
1508 ¤t->task_frag, getfrag,
1509 from, length, transhdrlen, flags);
1510 if (err) {
1511 __ip_flush_pending_frames(sk, &queue, &cork);
1512 return ERR_PTR(err);
1513 }
1514
1515 return __ip_make_skb(sk, fl4, &queue, &cork);
1516}
1517
1518/*
1519 * Fetch data from kernel space and fill in checksum if needed.
1520 */
1521static int ip_reply_glue_bits(void *dptr, char *to, int offset,
1522 int len, int odd, struct sk_buff *skb)
1523{
1524 __wsum csum;
1525
1526 csum = csum_partial_copy_nocheck(dptr+offset, to, len, 0);
1527 skb->csum = csum_block_add(skb->csum, csum, odd);
1528 return 0;
1529}
1530
1531/*
1532 * Generic function to send a packet as reply to another packet.
1533 * Used to send some TCP resets/acks so far.
1534 */
1535void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
1536 const struct ip_options *sopt,
1537 __be32 daddr, __be32 saddr,
1538 const struct ip_reply_arg *arg,
1539 unsigned int len)
1540{
1541 struct ip_options_data replyopts;
1542 struct ipcm_cookie ipc;
1543 struct flowi4 fl4;
1544 struct rtable *rt = skb_rtable(skb);
1545 struct net *net = sock_net(sk);
1546 struct sk_buff *nskb;
1547 int err;
1548 int oif;
1549
1550 if (__ip_options_echo(&replyopts.opt.opt, skb, sopt))
1551 return;
1552
1553 ipc.addr = daddr;
1554 ipc.opt = NULL;
1555 ipc.tx_flags = 0;
1556 ipc.ttl = 0;
1557 ipc.tos = -1;
1558
1559 if (replyopts.opt.opt.optlen) {
1560 ipc.opt = &replyopts.opt;
1561
1562 if (replyopts.opt.opt.srr)
1563 daddr = replyopts.opt.opt.faddr;
1564 }
1565
1566 oif = arg->bound_dev_if;
1567 if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
1568 oif = skb->skb_iif;
1569
1570 flowi4_init_output(&fl4, oif,
1571 IP4_REPLY_MARK(net, skb->mark),
1572 RT_TOS(arg->tos),
1573 RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
1574 ip_reply_arg_flowi_flags(arg),
1575 daddr, saddr,
1576 tcp_hdr(skb)->source, tcp_hdr(skb)->dest);
1577 security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
1578 rt = ip_route_output_key(net, &fl4);
1579 if (IS_ERR(rt))
1580 return;
1581
1582 inet_sk(sk)->tos = arg->tos;
1583
1584 sk->sk_priority = skb->priority;
1585 sk->sk_protocol = ip_hdr(skb)->protocol;
1586 sk->sk_bound_dev_if = arg->bound_dev_if;
1587 sk->sk_sndbuf = sysctl_wmem_default;
1588 err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base,
1589 len, 0, &ipc, &rt, MSG_DONTWAIT);
1590 if (unlikely(err)) {
1591 ip_flush_pending_frames(sk);
1592 goto out;
1593 }
1594
1595 nskb = skb_peek(&sk->sk_write_queue);
1596 if (nskb) {
1597 if (arg->csumoffset >= 0)
1598 *((__sum16 *)skb_transport_header(nskb) +
1599 arg->csumoffset) = csum_fold(csum_add(nskb->csum,
1600 arg->csum));
1601 nskb->ip_summed = CHECKSUM_NONE;
1602 ip_push_pending_frames(sk, &fl4);
1603 }
1604out:
1605 ip_rt_put(rt);
1606}
1607
1608void __init ip_init(void)
1609{
1610 ip_rt_init();
1611 inet_initpeers();
1612
1613#if defined(CONFIG_IP_MULTICAST)
1614 igmp_mc_init();
1615#endif
1616}