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[IPV4]: Add 'rtable' field in struct sk_buff to alias 'dst' and avoid casts
[deliverable/linux.git] / net / ipv4 / udp_ipv4.c
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 * UDP for IPv4.
7 *
8 * For full credits, see net/ipv4/udp.c.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16 #include <asm/system.h>
17 #include <asm/uaccess.h>
18 #include <asm/ioctls.h>
19 #include <linux/bootmem.h>
20 #include <linux/types.h>
21 #include <linux/fcntl.h>
22 #include <linux/module.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/igmp.h>
26 #include <linux/in.h>
27 #include <linux/errno.h>
28 #include <linux/timer.h>
29 #include <linux/mm.h>
30 #include <linux/inet.h>
31 #include <linux/netdevice.h>
32 #include <net/tcp_states.h>
33 #include <linux/skbuff.h>
34 #include <linux/proc_fs.h>
35 #include <linux/seq_file.h>
36 #include <net/net_namespace.h>
37 #include <net/icmp.h>
38 #include <net/route.h>
39 #include <net/checksum.h>
40 #include <net/xfrm.h>
41 #include "udp_impl.h"
42
43 int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
44 {
45 struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
46
47 return ( !ipv6_only_sock(sk2) &&
48 (!inet1->rcv_saddr || !inet2->rcv_saddr ||
49 inet1->rcv_saddr == inet2->rcv_saddr ));
50 }
51
52 static inline int udp_v4_get_port(struct sock *sk, unsigned short snum)
53 {
54 return udp_get_port(sk, snum, ipv4_rcv_saddr_equal);
55 }
56
57 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
58 * harder than this. -DaveM
59 */
60 static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
61 __be16 sport, __be32 daddr, __be16 dport,
62 int dif, struct hlist_head udptable[])
63 {
64 struct sock *sk, *result = NULL;
65 struct hlist_node *node;
66 unsigned short hnum = ntohs(dport);
67 int badness = -1;
68
69 read_lock(&udp_hash_lock);
70 sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) {
71 struct inet_sock *inet = inet_sk(sk);
72
73 if (sk->sk_net == net && sk->sk_hash == hnum &&
74 !ipv6_only_sock(sk)) {
75 int score = (sk->sk_family == PF_INET ? 1 : 0);
76 if (inet->rcv_saddr) {
77 if (inet->rcv_saddr != daddr)
78 continue;
79 score+=2;
80 }
81 if (inet->daddr) {
82 if (inet->daddr != saddr)
83 continue;
84 score+=2;
85 }
86 if (inet->dport) {
87 if (inet->dport != sport)
88 continue;
89 score+=2;
90 }
91 if (sk->sk_bound_dev_if) {
92 if (sk->sk_bound_dev_if != dif)
93 continue;
94 score+=2;
95 }
96 if (score == 9) {
97 result = sk;
98 break;
99 } else if (score > badness) {
100 result = sk;
101 badness = score;
102 }
103 }
104 }
105 if (result)
106 sock_hold(result);
107 read_unlock(&udp_hash_lock);
108 return result;
109 }
110
111 static inline struct sock *udp_v4_mcast_next(struct sock *sk,
112 __be16 loc_port, __be32 loc_addr,
113 __be16 rmt_port, __be32 rmt_addr,
114 int dif)
115 {
116 struct hlist_node *node;
117 struct sock *s = sk;
118 unsigned short hnum = ntohs(loc_port);
119
120 sk_for_each_from(s, node) {
121 struct inet_sock *inet = inet_sk(s);
122
123 if (s->sk_hash != hnum ||
124 (inet->daddr && inet->daddr != rmt_addr) ||
125 (inet->dport != rmt_port && inet->dport) ||
126 (inet->rcv_saddr && inet->rcv_saddr != loc_addr) ||
127 ipv6_only_sock(s) ||
128 (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
129 continue;
130 if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
131 continue;
132 goto found;
133 }
134 s = NULL;
135 found:
136 return s;
137 }
138
139 /*
140 * This routine is called by the ICMP module when it gets some
141 * sort of error condition. If err < 0 then the socket should
142 * be closed and the error returned to the user. If err > 0
143 * it's just the icmp type << 8 | icmp code.
144 * Header points to the ip header of the error packet. We move
145 * on past this. Then (as it used to claim before adjustment)
146 * header points to the first 8 bytes of the udp header. We need
147 * to find the appropriate port.
148 */
149
150 void __udp4_lib_err(struct sk_buff *skb, u32 info, struct hlist_head udptable[])
151 {
152 struct inet_sock *inet;
153 struct iphdr *iph = (struct iphdr*)skb->data;
154 struct udphdr *uh = (struct udphdr*)(skb->data+(iph->ihl<<2));
155 const int type = icmp_hdr(skb)->type;
156 const int code = icmp_hdr(skb)->code;
157 struct sock *sk;
158 int harderr;
159 int err;
160
161 sk = __udp4_lib_lookup(skb->dev->nd_net, iph->daddr, uh->dest,
162 iph->saddr, uh->source, skb->dev->ifindex, udptable);
163 if (sk == NULL) {
164 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
165 return; /* No socket for error */
166 }
167
168 err = 0;
169 harderr = 0;
170 inet = inet_sk(sk);
171
172 switch (type) {
173 default:
174 case ICMP_TIME_EXCEEDED:
175 err = EHOSTUNREACH;
176 break;
177 case ICMP_SOURCE_QUENCH:
178 goto out;
179 case ICMP_PARAMETERPROB:
180 err = EPROTO;
181 harderr = 1;
182 break;
183 case ICMP_DEST_UNREACH:
184 if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
185 if (inet->pmtudisc != IP_PMTUDISC_DONT) {
186 err = EMSGSIZE;
187 harderr = 1;
188 break;
189 }
190 goto out;
191 }
192 err = EHOSTUNREACH;
193 if (code <= NR_ICMP_UNREACH) {
194 harderr = icmp_err_convert[code].fatal;
195 err = icmp_err_convert[code].errno;
196 }
197 break;
198 }
199
200 /*
201 * RFC1122: OK. Passes ICMP errors back to application, as per
202 * 4.1.3.3.
203 */
204 if (!inet->recverr) {
205 if (!harderr || sk->sk_state != TCP_ESTABLISHED)
206 goto out;
207 } else {
208 ip_icmp_error(sk, skb, err, uh->dest, info, (u8*)(uh+1));
209 }
210 sk->sk_err = err;
211 sk->sk_error_report(sk);
212 out:
213 sock_put(sk);
214 }
215
216 void udp_err(struct sk_buff *skb, u32 info)
217 {
218 __udp4_lib_err(skb, info, udp_hash);
219 }
220
221 /*
222 * Throw away all pending data and cancel the corking. Socket is locked.
223 */
224 static void udp_flush_pending_frames(struct sock *sk)
225 {
226 struct udp_sock *up = udp_sk(sk);
227
228 if (up->pending) {
229 up->len = 0;
230 up->pending = 0;
231 ip_flush_pending_frames(sk);
232 }
233 }
234
235 /**
236 * udp4_hwcsum_outgoing - handle outgoing HW checksumming
237 * @sk: socket we are sending on
238 * @skb: sk_buff containing the filled-in UDP header
239 * (checksum field must be zeroed out)
240 */
241 static void udp4_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
242 __be32 src, __be32 dst, int len )
243 {
244 unsigned int offset;
245 struct udphdr *uh = udp_hdr(skb);
246 __wsum csum = 0;
247
248 if (skb_queue_len(&sk->sk_write_queue) == 1) {
249 /*
250 * Only one fragment on the socket.
251 */
252 skb->csum_start = skb_transport_header(skb) - skb->head;
253 skb->csum_offset = offsetof(struct udphdr, check);
254 uh->check = ~csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, 0);
255 } else {
256 /*
257 * HW-checksum won't work as there are two or more
258 * fragments on the socket so that all csums of sk_buffs
259 * should be together
260 */
261 offset = skb_transport_offset(skb);
262 skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
263
264 skb->ip_summed = CHECKSUM_NONE;
265
266 skb_queue_walk(&sk->sk_write_queue, skb) {
267 csum = csum_add(csum, skb->csum);
268 }
269
270 uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
271 if (uh->check == 0)
272 uh->check = CSUM_MANGLED_0;
273 }
274 }
275
276 /*
277 * Push out all pending data as one UDP datagram. Socket is locked.
278 */
279 static int udp_push_pending_frames(struct sock *sk)
280 {
281 struct udp_sock *up = udp_sk(sk);
282 struct inet_sock *inet = inet_sk(sk);
283 struct flowi *fl = &inet->cork.fl;
284 struct sk_buff *skb;
285 struct udphdr *uh;
286 int err = 0;
287 int is_udplite = IS_UDPLITE(sk);
288 __wsum csum = 0;
289
290 /* Grab the skbuff where UDP header space exists. */
291 if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
292 goto out;
293
294 /*
295 * Create a UDP header
296 */
297 uh = udp_hdr(skb);
298 uh->source = fl->fl_ip_sport;
299 uh->dest = fl->fl_ip_dport;
300 uh->len = htons(up->len);
301 uh->check = 0;
302
303 if (is_udplite) /* UDP-Lite */
304 csum = udplite_csum_outgoing(sk, skb);
305
306 else if (sk->sk_no_check == UDP_CSUM_NOXMIT) { /* UDP csum disabled */
307
308 skb->ip_summed = CHECKSUM_NONE;
309 goto send;
310
311 } else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
312
313 udp4_hwcsum_outgoing(sk, skb, fl->fl4_src,fl->fl4_dst, up->len);
314 goto send;
315
316 } else /* `normal' UDP */
317 csum = udp_csum_outgoing(sk, skb);
318
319 /* add protocol-dependent pseudo-header */
320 uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst, up->len,
321 sk->sk_protocol, csum );
322 if (uh->check == 0)
323 uh->check = CSUM_MANGLED_0;
324
325 send:
326 err = ip_push_pending_frames(sk);
327 out:
328 up->len = 0;
329 up->pending = 0;
330 if (!err)
331 UDP_INC_STATS_USER(UDP_MIB_OUTDATAGRAMS, is_udplite);
332 return err;
333 }
334
335 int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
336 size_t len)
337 {
338 struct inet_sock *inet = inet_sk(sk);
339 struct udp_sock *up = udp_sk(sk);
340 int ulen = len;
341 struct ipcm_cookie ipc;
342 struct rtable *rt = NULL;
343 int free = 0;
344 int connected = 0;
345 __be32 daddr, faddr, saddr;
346 __be16 dport;
347 u8 tos;
348 int err, is_udplite = IS_UDPLITE(sk);
349 int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
350 int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
351
352 if (len > 0xFFFF)
353 return -EMSGSIZE;
354
355 /*
356 * Check the flags.
357 */
358
359 if (msg->msg_flags&MSG_OOB) /* Mirror BSD error message compatibility */
360 return -EOPNOTSUPP;
361
362 ipc.opt = NULL;
363
364 if (up->pending) {
365 /*
366 * There are pending frames.
367 * The socket lock must be held while it's corked.
368 */
369 lock_sock(sk);
370 if (likely(up->pending)) {
371 if (unlikely(up->pending != AF_INET)) {
372 release_sock(sk);
373 return -EINVAL;
374 }
375 goto do_append_data;
376 }
377 release_sock(sk);
378 }
379 ulen += sizeof(struct udphdr);
380
381 /*
382 * Get and verify the address.
383 */
384 if (msg->msg_name) {
385 struct sockaddr_in * usin = (struct sockaddr_in*)msg->msg_name;
386 if (msg->msg_namelen < sizeof(*usin))
387 return -EINVAL;
388 if (usin->sin_family != AF_INET) {
389 if (usin->sin_family != AF_UNSPEC)
390 return -EAFNOSUPPORT;
391 }
392
393 daddr = usin->sin_addr.s_addr;
394 dport = usin->sin_port;
395 if (dport == 0)
396 return -EINVAL;
397 } else {
398 if (sk->sk_state != TCP_ESTABLISHED)
399 return -EDESTADDRREQ;
400 daddr = inet->daddr;
401 dport = inet->dport;
402 /* Open fast path for connected socket.
403 Route will not be used, if at least one option is set.
404 */
405 connected = 1;
406 }
407 ipc.addr = inet->saddr;
408
409 ipc.oif = sk->sk_bound_dev_if;
410 if (msg->msg_controllen) {
411 err = ip_cmsg_send(msg, &ipc);
412 if (err)
413 return err;
414 if (ipc.opt)
415 free = 1;
416 connected = 0;
417 }
418 if (!ipc.opt)
419 ipc.opt = inet->opt;
420
421 saddr = ipc.addr;
422 ipc.addr = faddr = daddr;
423
424 if (ipc.opt && ipc.opt->srr) {
425 if (!daddr)
426 return -EINVAL;
427 faddr = ipc.opt->faddr;
428 connected = 0;
429 }
430 tos = RT_TOS(inet->tos);
431 if (sock_flag(sk, SOCK_LOCALROUTE) ||
432 (msg->msg_flags & MSG_DONTROUTE) ||
433 (ipc.opt && ipc.opt->is_strictroute)) {
434 tos |= RTO_ONLINK;
435 connected = 0;
436 }
437
438 if (ipv4_is_multicast(daddr)) {
439 if (!ipc.oif)
440 ipc.oif = inet->mc_index;
441 if (!saddr)
442 saddr = inet->mc_addr;
443 connected = 0;
444 }
445
446 if (connected)
447 rt = (struct rtable*)sk_dst_check(sk, 0);
448
449 if (rt == NULL) {
450 struct flowi fl = { .oif = ipc.oif,
451 .nl_u = { .ip4_u =
452 { .daddr = faddr,
453 .saddr = saddr,
454 .tos = tos } },
455 .proto = sk->sk_protocol,
456 .uli_u = { .ports =
457 { .sport = inet->sport,
458 .dport = dport } } };
459 security_sk_classify_flow(sk, &fl);
460 err = ip_route_output_flow(&init_net, &rt, &fl, sk, 1);
461 if (err) {
462 if (err == -ENETUNREACH)
463 IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
464 goto out;
465 }
466
467 err = -EACCES;
468 if ((rt->rt_flags & RTCF_BROADCAST) &&
469 !sock_flag(sk, SOCK_BROADCAST))
470 goto out;
471 if (connected)
472 sk_dst_set(sk, dst_clone(&rt->u.dst));
473 }
474
475 if (msg->msg_flags&MSG_CONFIRM)
476 goto do_confirm;
477 back_from_confirm:
478
479 saddr = rt->rt_src;
480 if (!ipc.addr)
481 daddr = ipc.addr = rt->rt_dst;
482
483 lock_sock(sk);
484 if (unlikely(up->pending)) {
485 /* The socket is already corked while preparing it. */
486 /* ... which is an evident application bug. --ANK */
487 release_sock(sk);
488
489 LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
490 err = -EINVAL;
491 goto out;
492 }
493 /*
494 * Now cork the socket to pend data.
495 */
496 inet->cork.fl.fl4_dst = daddr;
497 inet->cork.fl.fl_ip_dport = dport;
498 inet->cork.fl.fl4_src = saddr;
499 inet->cork.fl.fl_ip_sport = inet->sport;
500 up->pending = AF_INET;
501
502 do_append_data:
503 up->len += ulen;
504 getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
505 err = ip_append_data(sk, getfrag, msg->msg_iov, ulen,
506 sizeof(struct udphdr), &ipc, rt,
507 corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
508 if (err)
509 udp_flush_pending_frames(sk);
510 else if (!corkreq)
511 err = udp_push_pending_frames(sk);
512 else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
513 up->pending = 0;
514 release_sock(sk);
515
516 out:
517 ip_rt_put(rt);
518 if (free)
519 kfree(ipc.opt);
520 if (!err)
521 return len;
522 /*
523 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting
524 * ENOBUFS might not be good (it's not tunable per se), but otherwise
525 * we don't have a good statistic (IpOutDiscards but it can be too many
526 * things). We could add another new stat but at least for now that
527 * seems like overkill.
528 */
529 if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
530 UDP_INC_STATS_USER(UDP_MIB_SNDBUFERRORS, is_udplite);
531 }
532 return err;
533
534 do_confirm:
535 dst_confirm(&rt->u.dst);
536 if (!(msg->msg_flags&MSG_PROBE) || len)
537 goto back_from_confirm;
538 err = 0;
539 goto out;
540 }
541
542 int udp_sendpage(struct sock *sk, struct page *page, int offset,
543 size_t size, int flags)
544 {
545 struct udp_sock *up = udp_sk(sk);
546 int ret;
547
548 if (!up->pending) {
549 struct msghdr msg = { .msg_flags = flags|MSG_MORE };
550
551 /* Call udp_sendmsg to specify destination address which
552 * sendpage interface can't pass.
553 * This will succeed only when the socket is connected.
554 */
555 ret = udp_sendmsg(NULL, sk, &msg, 0);
556 if (ret < 0)
557 return ret;
558 }
559
560 lock_sock(sk);
561
562 if (unlikely(!up->pending)) {
563 release_sock(sk);
564
565 LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n");
566 return -EINVAL;
567 }
568
569 ret = ip_append_page(sk, page, offset, size, flags);
570 if (ret == -EOPNOTSUPP) {
571 release_sock(sk);
572 return sock_no_sendpage(sk->sk_socket, page, offset,
573 size, flags);
574 }
575 if (ret < 0) {
576 udp_flush_pending_frames(sk);
577 goto out;
578 }
579
580 up->len += size;
581 if (!(up->corkflag || (flags&MSG_MORE)))
582 ret = udp_push_pending_frames(sk);
583 if (!ret)
584 ret = size;
585 out:
586 release_sock(sk);
587 return ret;
588 }
589
590 /*
591 * This should be easy, if there is something there we
592 * return it, otherwise we block.
593 */
594
595 int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
596 size_t len, int noblock, int flags, int *addr_len)
597 {
598 struct inet_sock *inet = inet_sk(sk);
599 struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
600 struct sk_buff *skb;
601 unsigned int ulen, copied;
602 int peeked;
603 int err;
604 int is_udplite = IS_UDPLITE(sk);
605
606 /*
607 * Check any passed addresses
608 */
609 if (addr_len)
610 *addr_len=sizeof(*sin);
611
612 if (flags & MSG_ERRQUEUE)
613 return ip_recv_error(sk, msg, len);
614
615 try_again:
616 skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
617 &peeked, &err);
618 if (!skb)
619 goto out;
620
621 ulen = skb->len - sizeof(struct udphdr);
622 copied = len;
623 if (copied > ulen)
624 copied = ulen;
625 else if (copied < ulen)
626 msg->msg_flags |= MSG_TRUNC;
627
628 /*
629 * If checksum is needed at all, try to do it while copying the
630 * data. If the data is truncated, or if we only want a partial
631 * coverage checksum (UDP-Lite), do it before the copy.
632 */
633
634 if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
635 if (udp_lib_checksum_complete(skb))
636 goto csum_copy_err;
637 }
638
639 if (skb_csum_unnecessary(skb))
640 err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
641 msg->msg_iov, copied );
642 else {
643 err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
644
645 if (err == -EINVAL)
646 goto csum_copy_err;
647 }
648
649 if (err)
650 goto out_free;
651
652 if (!peeked)
653 UDP_INC_STATS_USER(UDP_MIB_INDATAGRAMS, is_udplite);
654
655 sock_recv_timestamp(msg, sk, skb);
656
657 /* Copy the address. */
658 if (sin)
659 {
660 sin->sin_family = AF_INET;
661 sin->sin_port = udp_hdr(skb)->source;
662 sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
663 memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
664 }
665 if (inet->cmsg_flags)
666 ip_cmsg_recv(msg, skb);
667
668 err = copied;
669 if (flags & MSG_TRUNC)
670 err = ulen;
671
672 out_free:
673 lock_sock(sk);
674 skb_free_datagram(sk, skb);
675 release_sock(sk);
676 out:
677 return err;
678
679 csum_copy_err:
680 lock_sock(sk);
681 if (!skb_kill_datagram(sk, skb, flags))
682 UDP_INC_STATS_USER(UDP_MIB_INERRORS, is_udplite);
683 release_sock(sk);
684
685 if (noblock)
686 return -EAGAIN;
687 goto try_again;
688 }
689
690
691 /* returns:
692 * -1: error
693 * 0: success
694 * >0: "udp encap" protocol resubmission
695 *
696 * Note that in the success and error cases, the skb is assumed to
697 * have either been requeued or freed.
698 */
699 int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
700 {
701 struct udp_sock *up = udp_sk(sk);
702 int rc;
703 int is_udplite = IS_UDPLITE(sk);
704
705 /*
706 * Charge it to the socket, dropping if the queue is full.
707 */
708 if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
709 goto drop;
710 nf_reset(skb);
711
712 if (up->encap_type) {
713 /*
714 * This is an encapsulation socket so pass the skb to
715 * the socket's udp_encap_rcv() hook. Otherwise, just
716 * fall through and pass this up the UDP socket.
717 * up->encap_rcv() returns the following value:
718 * =0 if skb was successfully passed to the encap
719 * handler or was discarded by it.
720 * >0 if skb should be passed on to UDP.
721 * <0 if skb should be resubmitted as proto -N
722 */
723
724 /* if we're overly short, let UDP handle it */
725 if (skb->len > sizeof(struct udphdr) &&
726 up->encap_rcv != NULL) {
727 int ret;
728
729 ret = (*up->encap_rcv)(sk, skb);
730 if (ret <= 0) {
731 UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS,
732 is_udplite);
733 return -ret;
734 }
735 }
736
737 /* FALLTHROUGH -- it's a UDP Packet */
738 }
739
740 /*
741 * UDP-Lite specific tests, ignored on UDP sockets
742 */
743 if ((is_udplite & UDPLITE_RECV_CC) && UDP_SKB_CB(skb)->partial_cov) {
744
745 /*
746 * MIB statistics other than incrementing the error count are
747 * disabled for the following two types of errors: these depend
748 * on the application settings, not on the functioning of the
749 * protocol stack as such.
750 *
751 * RFC 3828 here recommends (sec 3.3): "There should also be a
752 * way ... to ... at least let the receiving application block
753 * delivery of packets with coverage values less than a value
754 * provided by the application."
755 */
756 if (up->pcrlen == 0) { /* full coverage was set */
757 LIMIT_NETDEBUG(KERN_WARNING "UDPLITE: partial coverage "
758 "%d while full coverage %d requested\n",
759 UDP_SKB_CB(skb)->cscov, skb->len);
760 goto drop;
761 }
762 /* The next case involves violating the min. coverage requested
763 * by the receiver. This is subtle: if receiver wants x and x is
764 * greater than the buffersize/MTU then receiver will complain
765 * that it wants x while sender emits packets of smaller size y.
766 * Therefore the above ...()->partial_cov statement is essential.
767 */
768 if (UDP_SKB_CB(skb)->cscov < up->pcrlen) {
769 LIMIT_NETDEBUG(KERN_WARNING
770 "UDPLITE: coverage %d too small, need min %d\n",
771 UDP_SKB_CB(skb)->cscov, up->pcrlen);
772 goto drop;
773 }
774 }
775
776 if (sk->sk_filter) {
777 if (udp_lib_checksum_complete(skb))
778 goto drop;
779 }
780
781 if ((rc = sock_queue_rcv_skb(sk,skb)) < 0) {
782 /* Note that an ENOMEM error is charged twice */
783 if (rc == -ENOMEM)
784 UDP_INC_STATS_BH(UDP_MIB_RCVBUFERRORS, is_udplite);
785 goto drop;
786 }
787
788 return 0;
789
790 drop:
791 UDP_INC_STATS_BH(UDP_MIB_INERRORS, is_udplite);
792 kfree_skb(skb);
793 return -1;
794 }
795
796 /*
797 * Multicasts and broadcasts go to each listener.
798 *
799 * Note: called only from the BH handler context,
800 * so we don't need to lock the hashes.
801 */
802 static int __udp4_lib_mcast_deliver(struct sk_buff *skb,
803 struct udphdr *uh,
804 __be32 saddr, __be32 daddr,
805 struct hlist_head udptable[])
806 {
807 struct sock *sk;
808 int dif;
809
810 read_lock(&udp_hash_lock);
811 sk = sk_head(&udptable[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]);
812 dif = skb->dev->ifindex;
813 sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif);
814 if (sk) {
815 struct sock *sknext = NULL;
816
817 do {
818 struct sk_buff *skb1 = skb;
819
820 sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr,
821 uh->source, saddr, dif);
822 if (sknext)
823 skb1 = skb_clone(skb, GFP_ATOMIC);
824
825 if (skb1) {
826 int ret = 0;
827
828 bh_lock_sock_nested(sk);
829 if (!sock_owned_by_user(sk))
830 ret = udp_queue_rcv_skb(sk, skb1);
831 else
832 sk_add_backlog(sk, skb1);
833 bh_unlock_sock(sk);
834
835 if (ret > 0)
836 /* we should probably re-process instead
837 * of dropping packets here. */
838 kfree_skb(skb1);
839 }
840 sk = sknext;
841 } while (sknext);
842 } else
843 kfree_skb(skb);
844 read_unlock(&udp_hash_lock);
845 return 0;
846 }
847
848 /* Initialize UDP checksum. If exited with zero value (success),
849 * CHECKSUM_UNNECESSARY means, that no more checks are required.
850 * Otherwise, csum completion requires chacksumming packet body,
851 * including udp header and folding it to skb->csum.
852 */
853 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
854 int proto)
855 {
856 const struct iphdr *iph;
857 int err;
858
859 UDP_SKB_CB(skb)->partial_cov = 0;
860 UDP_SKB_CB(skb)->cscov = skb->len;
861
862 if (IS_PROTO_UDPLITE(proto)) {
863 err = udplite_checksum_init(skb, uh);
864 if (err)
865 return err;
866 }
867
868 iph = ip_hdr(skb);
869 if (uh->check == 0) {
870 skb->ip_summed = CHECKSUM_UNNECESSARY;
871 } else if (skb->ip_summed == CHECKSUM_COMPLETE) {
872 if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
873 proto, skb->csum))
874 skb->ip_summed = CHECKSUM_UNNECESSARY;
875 }
876 if (!skb_csum_unnecessary(skb))
877 skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
878 skb->len, proto, 0);
879 /* Probably, we should checksum udp header (it should be in cache
880 * in any case) and data in tiny packets (< rx copybreak).
881 */
882
883 return 0;
884 }
885
886 /*
887 * All we need to do is get the socket, and then do a checksum.
888 */
889
890 int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
891 int proto)
892 {
893 struct sock *sk;
894 struct udphdr *uh = udp_hdr(skb);
895 unsigned short ulen;
896 struct rtable *rt = skb->rtable;
897 __be32 saddr = ip_hdr(skb)->saddr;
898 __be32 daddr = ip_hdr(skb)->daddr;
899
900 /*
901 * Validate the packet.
902 */
903 if (!pskb_may_pull(skb, sizeof(struct udphdr)))
904 goto drop; /* No space for header. */
905
906 ulen = ntohs(uh->len);
907 if (ulen > skb->len)
908 goto short_packet;
909
910 if (IS_PROTO_UDPLITE(proto)) {
911 /* UDP validates ulen. */
912 if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
913 goto short_packet;
914 uh = udp_hdr(skb);
915 }
916
917 if (udp4_csum_init(skb, uh, proto))
918 goto csum_error;
919
920 if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
921 return __udp4_lib_mcast_deliver(skb, uh, saddr, daddr, udptable);
922
923 sk = __udp4_lib_lookup(skb->dev->nd_net, saddr, uh->source, daddr,
924 uh->dest, inet_iif(skb), udptable);
925
926 if (sk != NULL) {
927 int ret = 0;
928 bh_lock_sock_nested(sk);
929 if (!sock_owned_by_user(sk))
930 ret = udp_queue_rcv_skb(sk, skb);
931 else
932 sk_add_backlog(sk, skb);
933 bh_unlock_sock(sk);
934 sock_put(sk);
935
936 /* a return value > 0 means to resubmit the input, but
937 * it wants the return to be -protocol, or 0
938 */
939 if (ret > 0)
940 return -ret;
941 return 0;
942 }
943
944 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
945 goto drop;
946 nf_reset(skb);
947
948 /* No socket. Drop packet silently, if checksum is wrong */
949 if (udp_lib_checksum_complete(skb))
950 goto csum_error;
951
952 UDP_INC_STATS_BH(UDP_MIB_NOPORTS, IS_PROTO_UDPLITE(proto));
953 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
954
955 /*
956 * Hmm. We got an UDP packet to a port to which we
957 * don't wanna listen. Ignore it.
958 */
959 kfree_skb(skb);
960 return 0;
961
962 short_packet:
963 LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %u.%u.%u.%u:%u %d/%d to %u.%u.%u.%u:%u\n",
964 IS_PROTO_UDPLITE(proto) ? "-Lite" : "",
965 NIPQUAD(saddr),
966 ntohs(uh->source),
967 ulen,
968 skb->len,
969 NIPQUAD(daddr),
970 ntohs(uh->dest));
971 goto drop;
972
973 csum_error:
974 /*
975 * RFC1122: OK. Discards the bad packet silently (as far as
976 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
977 */
978 LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %d.%d.%d.%d:%d to %d.%d.%d.%d:%d ulen %d\n",
979 IS_PROTO_UDPLITE(proto) ? "-Lite" : "",
980 NIPQUAD(saddr),
981 ntohs(uh->source),
982 NIPQUAD(daddr),
983 ntohs(uh->dest),
984 ulen);
985 drop:
986 UDP_INC_STATS_BH(UDP_MIB_INERRORS, IS_PROTO_UDPLITE(proto));
987 kfree_skb(skb);
988 return 0;
989 }
990
991 int udp_rcv(struct sk_buff *skb)
992 {
993 return __udp4_lib_rcv(skb, udp_hash, IPPROTO_UDP);
994 }
995
996 int udp_destroy_sock(struct sock *sk)
997 {
998 lock_sock(sk);
999 udp_flush_pending_frames(sk);
1000 release_sock(sk);
1001 return 0;
1002 }
1003
1004 int udp_setsockopt(struct sock *sk, int level, int optname,
1005 char __user *optval, int optlen)
1006 {
1007 if (IS_SOL_UDPFAMILY(level))
1008 return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1009 udp_push_pending_frames);
1010 return ip_setsockopt(sk, level, optname, optval, optlen);
1011 }
1012
1013 #ifdef CONFIG_COMPAT
1014 int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1015 char __user *optval, int optlen)
1016 {
1017 if (IS_SOL_UDPFAMILY(level))
1018 return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1019 udp_push_pending_frames);
1020 return compat_ip_setsockopt(sk, level, optname, optval, optlen);
1021 }
1022 #endif
1023
1024 int udp_getsockopt(struct sock *sk, int level, int optname,
1025 char __user *optval, int __user *optlen)
1026 {
1027 if (IS_SOL_UDPFAMILY(level))
1028 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1029 return ip_getsockopt(sk, level, optname, optval, optlen);
1030 }
1031
1032 #ifdef CONFIG_COMPAT
1033 int compat_udp_getsockopt(struct sock *sk, int level, int optname,
1034 char __user *optval, int __user *optlen)
1035 {
1036 if (IS_SOL_UDPFAMILY(level))
1037 return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1038 return compat_ip_getsockopt(sk, level, optname, optval, optlen);
1039 }
1040 #endif
1041
1042 /* ------------------------------------------------------------------------ */
1043 DEFINE_PROTO_INUSE(udp)
1044
1045 struct proto udp_prot = {
1046 .name = "UDP",
1047 .owner = THIS_MODULE,
1048 .close = udp_lib_close,
1049 .connect = ip4_datagram_connect,
1050 .disconnect = udp_disconnect,
1051 .ioctl = udp_ioctl,
1052 .destroy = udp_destroy_sock,
1053 .setsockopt = udp_setsockopt,
1054 .getsockopt = udp_getsockopt,
1055 .sendmsg = udp_sendmsg,
1056 .recvmsg = udp_recvmsg,
1057 .sendpage = udp_sendpage,
1058 .backlog_rcv = udp_queue_rcv_skb,
1059 .hash = udp_lib_hash,
1060 .unhash = udp_lib_unhash,
1061 .get_port = udp_v4_get_port,
1062 .memory_allocated = &udp_memory_allocated,
1063 .sysctl_mem = sysctl_udp_mem,
1064 .sysctl_wmem = &sysctl_udp_wmem_min,
1065 .sysctl_rmem = &sysctl_udp_rmem_min,
1066 .obj_size = sizeof(struct udp_sock),
1067 #ifdef CONFIG_COMPAT
1068 .compat_setsockopt = compat_udp_setsockopt,
1069 .compat_getsockopt = compat_udp_getsockopt,
1070 #endif
1071 REF_PROTO_INUSE(udp)
1072 };
1073
1074 /* ------------------------------------------------------------------------ */
1075 static void udp4_format_sock(struct sock *sp, char *tmpbuf, int bucket)
1076 {
1077 struct inet_sock *inet = inet_sk(sp);
1078 __be32 dest = inet->daddr;
1079 __be32 src = inet->rcv_saddr;
1080 __u16 destp = ntohs(inet->dport);
1081 __u16 srcp = ntohs(inet->sport);
1082
1083 sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
1084 " %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p",
1085 bucket, src, srcp, dest, destp, sp->sk_state,
1086 atomic_read(&sp->sk_wmem_alloc),
1087 atomic_read(&sp->sk_rmem_alloc),
1088 0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
1089 atomic_read(&sp->sk_refcnt), sp);
1090 }
1091
1092 int udp4_seq_show(struct seq_file *seq, void *v)
1093 {
1094 if (v == SEQ_START_TOKEN)
1095 seq_printf(seq, "%-127s\n",
1096 " sl local_address rem_address st tx_queue "
1097 "rx_queue tr tm->when retrnsmt uid timeout "
1098 "inode");
1099 else {
1100 char tmpbuf[129];
1101 struct udp_iter_state *state = seq->private;
1102
1103 udp4_format_sock(v, tmpbuf, state->bucket);
1104 seq_printf(seq, "%-127s\n", tmpbuf);
1105 }
1106 return 0;
1107 }
1108
1109 /* ------------------------------------------------------------------------ */
1110 #ifdef CONFIG_PROC_FS
1111 static struct file_operations udp4_seq_fops;
1112 static struct udp_seq_afinfo udp4_seq_afinfo = {
1113 .owner = THIS_MODULE,
1114 .name = "udp",
1115 .family = AF_INET,
1116 .hashtable = udp_hash,
1117 .seq_show = udp4_seq_show,
1118 .seq_fops = &udp4_seq_fops,
1119 };
1120
1121 int __init udp4_proc_init(void)
1122 {
1123 return udp_proc_register(&udp4_seq_afinfo);
1124 }
1125
1126 void udp4_proc_exit(void)
1127 {
1128 udp_proc_unregister(&udp4_seq_afinfo);
1129 }
1130 #endif /* CONFIG_PROC_FS */
1131
1132 EXPORT_SYMBOL(udp_prot);
1133 EXPORT_SYMBOL(udp_sendmsg);
1134
Linux kernel - Deliverables
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