udp.c 57.8 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		The User Datagram Protocol (UDP).
 *
8
 * Authors:	Ross Biro
L
Linus Torvalds 已提交
9 10
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
11
 *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
L
Linus Torvalds 已提交
12 13 14 15 16 17 18 19 20
 *		Hirokazu Takahashi, <taka@valinux.co.jp>
 *
 * Fixes:
 *		Alan Cox	:	verify_area() calls
 *		Alan Cox	: 	stopped close while in use off icmp
 *					messages. Not a fix but a botch that
 *					for udp at least is 'valid'.
 *		Alan Cox	:	Fixed icmp handling properly
 *		Alan Cox	: 	Correct error for oversized datagrams
21 22
 *		Alan Cox	:	Tidied select() semantics.
 *		Alan Cox	:	udp_err() fixed properly, also now
L
Linus Torvalds 已提交
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56
 *					select and read wake correctly on errors
 *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
 *		Alan Cox	:	UDP can count its memory
 *		Alan Cox	:	send to an unknown connection causes
 *					an ECONNREFUSED off the icmp, but
 *					does NOT close.
 *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
 *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
 *					bug no longer crashes it.
 *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
 *		Alan Cox	:	Uses skb_free_datagram
 *		Alan Cox	:	Added get/set sockopt support.
 *		Alan Cox	:	Broadcasting without option set returns EACCES.
 *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
 *		Alan Cox	:	Use ip_tos and ip_ttl
 *		Alan Cox	:	SNMP Mibs
 *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
 *		Matt Dillon	:	UDP length checks.
 *		Alan Cox	:	Smarter af_inet used properly.
 *		Alan Cox	:	Use new kernel side addressing.
 *		Alan Cox	:	Incorrect return on truncated datagram receive.
 *	Arnt Gulbrandsen 	:	New udp_send and stuff
 *		Alan Cox	:	Cache last socket
 *		Alan Cox	:	Route cache
 *		Jon Peatfield	:	Minor efficiency fix to sendto().
 *		Mike Shaver	:	RFC1122 checks.
 *		Alan Cox	:	Nonblocking error fix.
 *	Willy Konynenberg	:	Transparent proxying support.
 *		Mike McLagan	:	Routing by source
 *		David S. Miller	:	New socket lookup architecture.
 *					Last socket cache retained as it
 *					does have a high hit rate.
 *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
 *		Andi Kleen	:	Some cleanups, cache destination entry
57
 *					for connect.
L
Linus Torvalds 已提交
58 59 60 61 62 63 64 65 66 67 68 69 70
 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
 *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
 *					return ENOTCONN for unconnected sockets (POSIX)
 *		Janos Farkas	:	don't deliver multi/broadcasts to a different
 *					bound-to-device socket
 *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
 *					datagrams.
 *	Hirokazu Takahashi	:	sendfile() on UDP works now.
 *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
 *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
 *					a single port at the same time.
 *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
71
 *	James Chapman		:	Add L2TP encapsulation type.
L
Linus Torvalds 已提交
72 73 74 75 76 77 78
 *
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
79

80 81
#define pr_fmt(fmt) "UDP: " fmt

L
Linus Torvalds 已提交
82 83
#include <asm/uaccess.h>
#include <asm/ioctls.h>
H
Hideo Aoki 已提交
84
#include <linux/bootmem.h>
85 86
#include <linux/highmem.h>
#include <linux/swap.h>
L
Linus Torvalds 已提交
87 88 89 90 91
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
92
#include <linux/igmp.h>
L
Linus Torvalds 已提交
93 94 95 96 97 98
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
99
#include <linux/slab.h>
100
#include <net/tcp_states.h>
L
Linus Torvalds 已提交
101 102 103
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
104
#include <net/net_namespace.h>
L
Linus Torvalds 已提交
105 106 107 108
#include <net/icmp.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
109
#include <trace/events/udp.h>
110
#include <linux/static_key.h>
111
#include <trace/events/skb.h>
112
#include "udp_impl.h"
L
Linus Torvalds 已提交
113

114
struct udp_table udp_table __read_mostly;
115
EXPORT_SYMBOL(udp_table);
L
Linus Torvalds 已提交
116

E
Eric Dumazet 已提交
117
long sysctl_udp_mem[3] __read_mostly;
H
Hideo Aoki 已提交
118
EXPORT_SYMBOL(sysctl_udp_mem);
E
Eric Dumazet 已提交
119 120

int sysctl_udp_rmem_min __read_mostly;
H
Hideo Aoki 已提交
121
EXPORT_SYMBOL(sysctl_udp_rmem_min);
E
Eric Dumazet 已提交
122 123

int sysctl_udp_wmem_min __read_mostly;
H
Hideo Aoki 已提交
124 125
EXPORT_SYMBOL(sysctl_udp_wmem_min);

E
Eric Dumazet 已提交
126
atomic_long_t udp_memory_allocated;
H
Hideo Aoki 已提交
127 128
EXPORT_SYMBOL(udp_memory_allocated);

129 130
#define MAX_UDP_PORTS 65536
#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
131

132
static int udp_lib_lport_inuse(struct net *net, __u16 num,
133
			       const struct udp_hslot *hslot,
134
			       unsigned long *bitmap,
135 136
			       struct sock *sk,
			       int (*saddr_comp)(const struct sock *sk1,
137 138
						 const struct sock *sk2),
			       unsigned int log)
L
Linus Torvalds 已提交
139
{
140
	struct sock *sk2;
141
	struct hlist_nulls_node *node;
142

143
	sk_nulls_for_each(sk2, node, &hslot->head)
144 145
		if (net_eq(sock_net(sk2), net) &&
		    sk2 != sk &&
146
		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
147 148 149
		    (!sk2->sk_reuse || !sk->sk_reuse) &&
		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
150 151
		    (*saddr_comp)(sk, sk2)) {
			if (bitmap)
152 153
				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
					  bitmap);
154 155 156
			else
				return 1;
		}
157 158 159
	return 0;
}

E
Eric Dumazet 已提交
160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175
/*
 * Note: we still hold spinlock of primary hash chain, so no other writer
 * can insert/delete a socket with local_port == num
 */
static int udp_lib_lport_inuse2(struct net *net, __u16 num,
			       struct udp_hslot *hslot2,
			       struct sock *sk,
			       int (*saddr_comp)(const struct sock *sk1,
						 const struct sock *sk2))
{
	struct sock *sk2;
	struct hlist_nulls_node *node;
	int res = 0;

	spin_lock(&hslot2->lock);
	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
176 177 178 179 180 181
		if (net_eq(sock_net(sk2), net) &&
		    sk2 != sk &&
		    (udp_sk(sk2)->udp_port_hash == num) &&
		    (!sk2->sk_reuse || !sk->sk_reuse) &&
		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
E
Eric Dumazet 已提交
182 183 184 185 186 187 188 189
		    (*saddr_comp)(sk, sk2)) {
			res = 1;
			break;
		}
	spin_unlock(&hslot2->lock);
	return res;
}

190
/**
191
 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
192 193 194
 *
 *  @sk:          socket struct in question
 *  @snum:        port number to look up
195
 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
L
Lucas De Marchi 已提交
196
 *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
E
Eric Dumazet 已提交
197
 *                   with NULL address
198
 */
199
int udp_lib_get_port(struct sock *sk, unsigned short snum,
200
		       int (*saddr_comp)(const struct sock *sk1,
E
Eric Dumazet 已提交
201 202
					 const struct sock *sk2),
		     unsigned int hash2_nulladdr)
203
{
204
	struct udp_hslot *hslot, *hslot2;
205
	struct udp_table *udptable = sk->sk_prot->h.udp_table;
206
	int    error = 1;
207
	struct net *net = sock_net(sk);
L
Linus Torvalds 已提交
208

209
	if (!snum) {
E
Eric Dumazet 已提交
210
		int low, high, remaining;
211
		unsigned int rand;
212 213
		unsigned short first, last;
		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
214

215
		inet_get_local_port_range(&low, &high);
216
		remaining = (high - low) + 1;
217

E
Eric Dumazet 已提交
218
		rand = net_random();
219 220 221 222
		first = (((u64)rand * remaining) >> 32) + low;
		/*
		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
		 */
223
		rand = (rand | 1) * (udptable->mask + 1);
E
Eric Dumazet 已提交
224 225
		last = first + udptable->mask + 1;
		do {
226
			hslot = udp_hashslot(udptable, net, first);
227
			bitmap_zero(bitmap, PORTS_PER_CHAIN);
228
			spin_lock_bh(&hslot->lock);
229
			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
230
					    saddr_comp, udptable->log);
231 232 233 234 235 236 237

			snum = first;
			/*
			 * Iterate on all possible values of snum for this hash.
			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
			 * give us randomization and full range coverage.
			 */
E
Eric Dumazet 已提交
238
			do {
239
				if (low <= snum && snum <= high &&
240 241
				    !test_bit(snum >> udptable->log, bitmap) &&
				    !inet_is_reserved_local_port(snum))
242 243 244 245
					goto found;
				snum += rand;
			} while (snum != first);
			spin_unlock_bh(&hslot->lock);
E
Eric Dumazet 已提交
246
		} while (++first != last);
247
		goto fail;
248
	} else {
249
		hslot = udp_hashslot(udptable, net, snum);
250
		spin_lock_bh(&hslot->lock);
E
Eric Dumazet 已提交
251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274
		if (hslot->count > 10) {
			int exist;
			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;

			slot2          &= udptable->mask;
			hash2_nulladdr &= udptable->mask;

			hslot2 = udp_hashslot2(udptable, slot2);
			if (hslot->count < hslot2->count)
				goto scan_primary_hash;

			exist = udp_lib_lport_inuse2(net, snum, hslot2,
						     sk, saddr_comp);
			if (!exist && (hash2_nulladdr != slot2)) {
				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
				exist = udp_lib_lport_inuse2(net, snum, hslot2,
							     sk, saddr_comp);
			}
			if (exist)
				goto fail_unlock;
			else
				goto found;
		}
scan_primary_hash:
275 276
		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
					saddr_comp, 0))
277 278
			goto fail_unlock;
	}
279
found:
E
Eric Dumazet 已提交
280
	inet_sk(sk)->inet_num = snum;
281 282
	udp_sk(sk)->udp_port_hash = snum;
	udp_sk(sk)->udp_portaddr_hash ^= snum;
L
Linus Torvalds 已提交
283
	if (sk_unhashed(sk)) {
284
		sk_nulls_add_node_rcu(sk, &hslot->head);
E
Eric Dumazet 已提交
285
		hslot->count++;
286
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
287 288 289 290 291 292 293

		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
		spin_lock(&hslot2->lock);
		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
					 &hslot2->head);
		hslot2->count++;
		spin_unlock(&hslot2->lock);
L
Linus Torvalds 已提交
294
	}
295
	error = 0;
296 297
fail_unlock:
	spin_unlock_bh(&hslot->lock);
L
Linus Torvalds 已提交
298
fail:
299 300
	return error;
}
E
Eric Dumazet 已提交
301
EXPORT_SYMBOL(udp_lib_get_port);
302

303
static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
304 305 306
{
	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);

E
Eric Dumazet 已提交
307
	return 	(!ipv6_only_sock(sk2)  &&
E
Eric Dumazet 已提交
308 309
		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
310 311
}

312 313 314
static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
				       unsigned int port)
{
315
	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
316 317
}

318
int udp_v4_get_port(struct sock *sk, unsigned short snum)
319
{
E
Eric Dumazet 已提交
320
	unsigned int hash2_nulladdr =
321
		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
E
Eric Dumazet 已提交
322 323 324
	unsigned int hash2_partial =
		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);

325
	/* precompute partial secondary hash */
E
Eric Dumazet 已提交
326 327
	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
328 329
}

330 331 332 333 334 335
static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
			 unsigned short hnum,
			 __be16 sport, __be32 daddr, __be16 dport, int dif)
{
	int score = -1;

336
	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
337 338 339 340
			!ipv6_only_sock(sk)) {
		struct inet_sock *inet = inet_sk(sk);

		score = (sk->sk_family == PF_INET ? 1 : 0);
E
Eric Dumazet 已提交
341 342
		if (inet->inet_rcv_saddr) {
			if (inet->inet_rcv_saddr != daddr)
343 344 345
				return -1;
			score += 2;
		}
E
Eric Dumazet 已提交
346 347
		if (inet->inet_daddr) {
			if (inet->inet_daddr != saddr)
348 349 350
				return -1;
			score += 2;
		}
E
Eric Dumazet 已提交
351 352
		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
353 354 355 356 357 358 359 360 361 362 363 364
				return -1;
			score += 2;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score += 2;
		}
	}
	return score;
}

E
Eric Dumazet 已提交
365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436
/*
 * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
 */
#define SCORE2_MAX (1 + 2 + 2 + 2)
static inline int compute_score2(struct sock *sk, struct net *net,
				 __be32 saddr, __be16 sport,
				 __be32 daddr, unsigned int hnum, int dif)
{
	int score = -1;

	if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
		struct inet_sock *inet = inet_sk(sk);

		if (inet->inet_rcv_saddr != daddr)
			return -1;
		if (inet->inet_num != hnum)
			return -1;

		score = (sk->sk_family == PF_INET ? 1 : 0);
		if (inet->inet_daddr) {
			if (inet->inet_daddr != saddr)
				return -1;
			score += 2;
		}
		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
				return -1;
			score += 2;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score += 2;
		}
	}
	return score;
}


/* called with read_rcu_lock() */
static struct sock *udp4_lib_lookup2(struct net *net,
		__be32 saddr, __be16 sport,
		__be32 daddr, unsigned int hnum, int dif,
		struct udp_hslot *hslot2, unsigned int slot2)
{
	struct sock *sk, *result;
	struct hlist_nulls_node *node;
	int score, badness;

begin:
	result = NULL;
	badness = -1;
	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
		score = compute_score2(sk, net, saddr, sport,
				      daddr, hnum, dif);
		if (score > badness) {
			result = sk;
			badness = score;
			if (score == SCORE2_MAX)
				goto exact_match;
		}
	}
	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
	if (get_nulls_value(node) != slot2)
		goto begin;

	if (result) {
exact_match:
E
Eric Dumazet 已提交
437
		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
E
Eric Dumazet 已提交
438 439 440 441 442 443 444 445 446 447
			result = NULL;
		else if (unlikely(compute_score2(result, net, saddr, sport,
				  daddr, hnum, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	return result;
}

448 449 450
/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 * harder than this. -DaveM
 */
451
struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
452
		__be16 sport, __be32 daddr, __be16 dport,
453
		int dif, struct udp_table *udptable)
454
{
455
	struct sock *sk, *result;
456
	struct hlist_nulls_node *node;
457
	unsigned short hnum = ntohs(dport);
E
Eric Dumazet 已提交
458 459
	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
460
	int score, badness;
461

462
	rcu_read_lock();
E
Eric Dumazet 已提交
463 464 465 466 467 468 469 470 471 472 473
	if (hslot->count > 10) {
		hash2 = udp4_portaddr_hash(net, daddr, hnum);
		slot2 = hash2 & udptable->mask;
		hslot2 = &udptable->hash2[slot2];
		if (hslot->count < hslot2->count)
			goto begin;

		result = udp4_lib_lookup2(net, saddr, sport,
					  daddr, hnum, dif,
					  hslot2, slot2);
		if (!result) {
474
			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
E
Eric Dumazet 已提交
475 476 477 478 479
			slot2 = hash2 & udptable->mask;
			hslot2 = &udptable->hash2[slot2];
			if (hslot->count < hslot2->count)
				goto begin;

480
			result = udp4_lib_lookup2(net, saddr, sport,
481
						  htonl(INADDR_ANY), hnum, dif,
E
Eric Dumazet 已提交
482 483 484 485 486
						  hslot2, slot2);
		}
		rcu_read_unlock();
		return result;
	}
487 488 489
begin:
	result = NULL;
	badness = -1;
490
	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
491 492 493 494 495
		score = compute_score(sk, net, saddr, hnum, sport,
				      daddr, dport, dif);
		if (score > badness) {
			result = sk;
			badness = score;
496 497
		}
	}
498 499 500 501 502
	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
E
Eric Dumazet 已提交
503
	if (get_nulls_value(node) != slot)
504 505
		goto begin;

506
	if (result) {
E
Eric Dumazet 已提交
507
		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
508 509 510 511 512 513 514 515
			result = NULL;
		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
				  daddr, dport, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	rcu_read_unlock();
516 517
	return result;
}
518
EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
519

520 521
static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
						 __be16 sport, __be16 dport,
522
						 struct udp_table *udptable)
523
{
524
	struct sock *sk;
525 526
	const struct iphdr *iph = ip_hdr(skb);

527 528 529
	if (unlikely(sk = skb_steal_sock(skb)))
		return sk;
	else
E
Eric Dumazet 已提交
530
		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
531 532
					 iph->daddr, dport, inet_iif(skb),
					 udptable);
533 534
}

535 536 537
struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
			     __be32 daddr, __be16 dport, int dif)
{
538
	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
539 540 541
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);

542
static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
543 544 545 546
					     __be16 loc_port, __be32 loc_addr,
					     __be16 rmt_port, __be32 rmt_addr,
					     int dif)
{
547
	struct hlist_nulls_node *node;
548 549 550
	struct sock *s = sk;
	unsigned short hnum = ntohs(loc_port);

551
	sk_nulls_for_each_from(s, node) {
552 553
		struct inet_sock *inet = inet_sk(s);

554 555 556 557 558 559 560
		if (!net_eq(sock_net(s), net) ||
		    udp_sk(s)->udp_port_hash != hnum ||
		    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
		    (inet->inet_dport != rmt_port && inet->inet_dport) ||
		    (inet->inet_rcv_saddr &&
		     inet->inet_rcv_saddr != loc_addr) ||
		    ipv6_only_sock(s) ||
561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582
		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
			continue;
		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
			continue;
		goto found;
	}
	s = NULL;
found:
	return s;
}

/*
 * This routine is called by the ICMP module when it gets some
 * sort of error condition.  If err < 0 then the socket should
 * be closed and the error returned to the user.  If err > 0
 * it's just the icmp type << 8 | icmp code.
 * Header points to the ip header of the error packet. We move
 * on past this. Then (as it used to claim before adjustment)
 * header points to the first 8 bytes of the udp header.  We need
 * to find the appropriate port.
 */

583
void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
584 585
{
	struct inet_sock *inet;
586
	const struct iphdr *iph = (const struct iphdr *)skb->data;
E
Eric Dumazet 已提交
587
	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
588 589 590 591 592
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	struct sock *sk;
	int harderr;
	int err;
593
	struct net *net = dev_net(skb->dev);
594

595
	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
596 597
			iph->saddr, uh->source, skb->dev->ifindex, udptable);
	if (sk == NULL) {
598
		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618
		return;	/* No socket for error */
	}

	err = 0;
	harderr = 0;
	inet = inet_sk(sk);

	switch (type) {
	default:
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	case ICMP_SOURCE_QUENCH:
		goto out;
	case ICMP_PARAMETERPROB:
		err = EPROTO;
		harderr = 1;
		break;
	case ICMP_DEST_UNREACH:
		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
619
			ipv4_sk_update_pmtu(skb, sk, info);
620 621 622 623 624 625 626 627 628 629 630 631 632
			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
				err = EMSGSIZE;
				harderr = 1;
				break;
			}
			goto out;
		}
		err = EHOSTUNREACH;
		if (code <= NR_ICMP_UNREACH) {
			harderr = icmp_err_convert[code].fatal;
			err = icmp_err_convert[code].errno;
		}
		break;
633 634 635
	case ICMP_REDIRECT:
		ipv4_sk_redirect(skb, sk);
		break;
636 637 638 639 640 641 642 643 644
	}

	/*
	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
	 *	4.1.3.3.
	 */
	if (!inet->recverr) {
		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
			goto out;
645
	} else
E
Eric Dumazet 已提交
646
		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
647

648 649 650 651 652 653 654 655
	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

void udp_err(struct sk_buff *skb, u32 info)
{
656
	__udp4_lib_err(skb, info, &udp_table);
657 658 659 660 661
}

/*
 * Throw away all pending data and cancel the corking. Socket is locked.
 */
662
void udp_flush_pending_frames(struct sock *sk)
663 664 665 666 667 668 669 670 671
{
	struct udp_sock *up = udp_sk(sk);

	if (up->pending) {
		up->len = 0;
		up->pending = 0;
		ip_flush_pending_frames(sk);
	}
}
672
EXPORT_SYMBOL(udp_flush_pending_frames);
673 674

/**
H
Herbert Xu 已提交
675
 * 	udp4_hwcsum  -  handle outgoing HW checksumming
676 677
 * 	@skb: 	sk_buff containing the filled-in UDP header
 * 	        (checksum field must be zeroed out)
H
Herbert Xu 已提交
678 679
 *	@src:	source IP address
 *	@dst:	destination IP address
680
 */
H
Herbert Xu 已提交
681
static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
682 683
{
	struct udphdr *uh = udp_hdr(skb);
H
Herbert Xu 已提交
684 685 686 687
	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
	int offset = skb_transport_offset(skb);
	int len = skb->len - offset;
	int hlen = len;
688 689
	__wsum csum = 0;

H
Herbert Xu 已提交
690
	if (!frags) {
691 692 693 694 695
		/*
		 * Only one fragment on the socket.
		 */
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
H
Herbert Xu 已提交
696 697
		uh->check = ~csum_tcpudp_magic(src, dst, len,
					       IPPROTO_UDP, 0);
698 699 700 701 702 703
	} else {
		/*
		 * HW-checksum won't work as there are two or more
		 * fragments on the socket so that all csums of sk_buffs
		 * should be together
		 */
H
Herbert Xu 已提交
704 705 706 707
		do {
			csum = csum_add(csum, frags->csum);
			hlen -= frags->len;
		} while ((frags = frags->next));
708

H
Herbert Xu 已提交
709
		csum = skb_checksum(skb, offset, hlen, csum);
710 711 712 713 714 715 716 717
		skb->ip_summed = CHECKSUM_NONE;

		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
		if (uh->check == 0)
			uh->check = CSUM_MANGLED_0;
	}
}

718
static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
719
{
H
Herbert Xu 已提交
720
	struct sock *sk = skb->sk;
721 722 723 724
	struct inet_sock *inet = inet_sk(sk);
	struct udphdr *uh;
	int err = 0;
	int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
725 726
	int offset = skb_transport_offset(skb);
	int len = skb->len - offset;
727 728 729 730 731 732
	__wsum csum = 0;

	/*
	 * Create a UDP header
	 */
	uh = udp_hdr(skb);
H
Herbert Xu 已提交
733
	uh->source = inet->inet_sport;
734
	uh->dest = fl4->fl4_dport;
H
Herbert Xu 已提交
735
	uh->len = htons(len);
736 737 738
	uh->check = 0;

	if (is_udplite)  				 /*     UDP-Lite      */
H
Herbert Xu 已提交
739
		csum = udplite_csum(skb);
740 741 742 743 744 745 746 747

	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */

		skb->ip_summed = CHECKSUM_NONE;
		goto send;

	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */

748
		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
749 750
		goto send;

H
Herbert Xu 已提交
751 752
	} else
		csum = udp_csum(skb);
753 754

	/* add protocol-dependent pseudo-header */
755
	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
E
Eric Dumazet 已提交
756
				      sk->sk_protocol, csum);
757 758 759 760
	if (uh->check == 0)
		uh->check = CSUM_MANGLED_0;

send:
E
Eric Dumazet 已提交
761
	err = ip_send_skb(sock_net(sk), skb);
E
Eric Dumazet 已提交
762 763 764 765 766 767 768 769 770
	if (err) {
		if (err == -ENOBUFS && !inet->recverr) {
			UDP_INC_STATS_USER(sock_net(sk),
					   UDP_MIB_SNDBUFERRORS, is_udplite);
			err = 0;
		}
	} else
		UDP_INC_STATS_USER(sock_net(sk),
				   UDP_MIB_OUTDATAGRAMS, is_udplite);
H
Herbert Xu 已提交
771 772 773 774 775 776 777 778 779 780
	return err;
}

/*
 * Push out all pending data as one UDP datagram. Socket is locked.
 */
static int udp_push_pending_frames(struct sock *sk)
{
	struct udp_sock  *up = udp_sk(sk);
	struct inet_sock *inet = inet_sk(sk);
D
David S. Miller 已提交
781
	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
H
Herbert Xu 已提交
782 783 784
	struct sk_buff *skb;
	int err = 0;

785
	skb = ip_finish_skb(sk, fl4);
H
Herbert Xu 已提交
786 787 788
	if (!skb)
		goto out;

789
	err = udp_send_skb(skb, fl4);
H
Herbert Xu 已提交
790

791 792 793 794 795 796 797 798 799 800 801
out:
	up->len = 0;
	up->pending = 0;
	return err;
}

int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct udp_sock *up = udp_sk(sk);
802
	struct flowi4 fl4_stack;
D
David S. Miller 已提交
803
	struct flowi4 *fl4;
804 805 806 807 808 809 810 811 812 813 814
	int ulen = len;
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	int free = 0;
	int connected = 0;
	__be32 daddr, faddr, saddr;
	__be16 dport;
	u8  tos;
	int err, is_udplite = IS_UDPLITE(sk);
	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
H
Herbert Xu 已提交
815
	struct sk_buff *skb;
816
	struct ip_options_data opt_copy;
817 818 819 820 821 822 823 824

	if (len > 0xFFFF)
		return -EMSGSIZE;

	/*
	 *	Check the flags.
	 */

E
Eric Dumazet 已提交
825
	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
826 827 828
		return -EOPNOTSUPP;

	ipc.opt = NULL;
829
	ipc.tx_flags = 0;
830

H
Herbert Xu 已提交
831 832
	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;

833
	fl4 = &inet->cork.fl.u.ip4;
834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854
	if (up->pending) {
		/*
		 * There are pending frames.
		 * The socket lock must be held while it's corked.
		 */
		lock_sock(sk);
		if (likely(up->pending)) {
			if (unlikely(up->pending != AF_INET)) {
				release_sock(sk);
				return -EINVAL;
			}
			goto do_append_data;
		}
		release_sock(sk);
	}
	ulen += sizeof(struct udphdr);

	/*
	 *	Get and verify the address.
	 */
	if (msg->msg_name) {
D
Daniel Baluta 已提交
855
		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
856 857 858 859 860 861 862 863 864 865 866 867 868 869
		if (msg->msg_namelen < sizeof(*usin))
			return -EINVAL;
		if (usin->sin_family != AF_INET) {
			if (usin->sin_family != AF_UNSPEC)
				return -EAFNOSUPPORT;
		}

		daddr = usin->sin_addr.s_addr;
		dport = usin->sin_port;
		if (dport == 0)
			return -EINVAL;
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;
E
Eric Dumazet 已提交
870 871
		daddr = inet->inet_daddr;
		dport = inet->inet_dport;
872 873 874 875 876
		/* Open fast path for connected socket.
		   Route will not be used, if at least one option is set.
		 */
		connected = 1;
	}
E
Eric Dumazet 已提交
877
	ipc.addr = inet->inet_saddr;
878 879

	ipc.oif = sk->sk_bound_dev_if;
880
	err = sock_tx_timestamp(sk, &ipc.tx_flags);
881 882
	if (err)
		return err;
883
	if (msg->msg_controllen) {
884
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
885 886 887 888 889 890
		if (err)
			return err;
		if (ipc.opt)
			free = 1;
		connected = 0;
	}
891 892 893 894 895 896 897 898 899 900 901 902
	if (!ipc.opt) {
		struct ip_options_rcu *inet_opt;

		rcu_read_lock();
		inet_opt = rcu_dereference(inet->inet_opt);
		if (inet_opt) {
			memcpy(&opt_copy, inet_opt,
			       sizeof(*inet_opt) + inet_opt->opt.optlen);
			ipc.opt = &opt_copy.opt;
		}
		rcu_read_unlock();
	}
903 904 905 906

	saddr = ipc.addr;
	ipc.addr = faddr = daddr;

907
	if (ipc.opt && ipc.opt->opt.srr) {
908 909
		if (!daddr)
			return -EINVAL;
910
		faddr = ipc.opt->opt.faddr;
911 912 913 914 915
		connected = 0;
	}
	tos = RT_TOS(inet->tos);
	if (sock_flag(sk, SOCK_LOCALROUTE) ||
	    (msg->msg_flags & MSG_DONTROUTE) ||
916
	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
917 918 919 920 921 922 923 924 925 926
		tos |= RTO_ONLINK;
		connected = 0;
	}

	if (ipv4_is_multicast(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
		connected = 0;
927 928
	} else if (!ipc.oif)
		ipc.oif = inet->uc_index;
929 930

	if (connected)
E
Eric Dumazet 已提交
931
		rt = (struct rtable *)sk_dst_check(sk, 0);
932 933

	if (rt == NULL) {
934 935
		struct net *net = sock_net(sk);

936 937
		fl4 = &fl4_stack;
		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
938 939 940 941
				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
				   inet_sk_flowi_flags(sk)|FLOWI_FLAG_CAN_SLEEP,
				   faddr, saddr, dport, inet->inet_sport);

942 943
		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
		rt = ip_route_output_flow(net, fl4, sk);
944 945
		if (IS_ERR(rt)) {
			err = PTR_ERR(rt);
946
			rt = NULL;
947
			if (err == -ENETUNREACH)
948
				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
949 950 951 952 953 954 955 956
			goto out;
		}

		err = -EACCES;
		if ((rt->rt_flags & RTCF_BROADCAST) &&
		    !sock_flag(sk, SOCK_BROADCAST))
			goto out;
		if (connected)
957
			sk_dst_set(sk, dst_clone(&rt->dst));
958 959 960 961 962 963
	}

	if (msg->msg_flags&MSG_CONFIRM)
		goto do_confirm;
back_from_confirm:

964
	saddr = fl4->saddr;
965
	if (!ipc.addr)
966
		daddr = ipc.addr = fl4->daddr;
967

H
Herbert Xu 已提交
968 969
	/* Lockless fast path for the non-corking case. */
	if (!corkreq) {
970
		skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
H
Herbert Xu 已提交
971 972 973
				  sizeof(struct udphdr), &ipc, &rt,
				  msg->msg_flags);
		err = PTR_ERR(skb);
974
		if (!IS_ERR_OR_NULL(skb))
975
			err = udp_send_skb(skb, fl4);
H
Herbert Xu 已提交
976 977 978
		goto out;
	}

979 980 981 982 983 984
	lock_sock(sk);
	if (unlikely(up->pending)) {
		/* The socket is already corked while preparing it. */
		/* ... which is an evident application bug. --ANK */
		release_sock(sk);

985
		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("cork app bug 2\n"));
986 987 988 989 990 991
		err = -EINVAL;
		goto out;
	}
	/*
	 *	Now cork the socket to pend data.
	 */
D
David S. Miller 已提交
992 993 994
	fl4 = &inet->cork.fl.u.ip4;
	fl4->daddr = daddr;
	fl4->saddr = saddr;
995 996
	fl4->fl4_dport = dport;
	fl4->fl4_sport = inet->inet_sport;
997 998 999 1000
	up->pending = AF_INET;

do_append_data:
	up->len += ulen;
1001 1002 1003
	err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
			     sizeof(struct udphdr), &ipc, &rt,
			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025
	if (err)
		udp_flush_pending_frames(sk);
	else if (!corkreq)
		err = udp_push_pending_frames(sk);
	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
		up->pending = 0;
	release_sock(sk);

out:
	ip_rt_put(rt);
	if (free)
		kfree(ipc.opt);
	if (!err)
		return len;
	/*
	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
	 * we don't have a good statistic (IpOutDiscards but it can be too many
	 * things).  We could add another new stat but at least for now that
	 * seems like overkill.
	 */
	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1026 1027
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_SNDBUFERRORS, is_udplite);
1028 1029 1030 1031
	}
	return err;

do_confirm:
1032
	dst_confirm(&rt->dst);
1033 1034 1035 1036 1037
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}
E
Eric Dumazet 已提交
1038
EXPORT_SYMBOL(udp_sendmsg);
1039 1040 1041 1042

int udp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
{
1043
	struct inet_sock *inet = inet_sk(sk);
1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
	struct udp_sock *up = udp_sk(sk);
	int ret;

	if (!up->pending) {
		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };

		/* Call udp_sendmsg to specify destination address which
		 * sendpage interface can't pass.
		 * This will succeed only when the socket is connected.
		 */
		ret = udp_sendmsg(NULL, sk, &msg, 0);
		if (ret < 0)
			return ret;
	}

	lock_sock(sk);

	if (unlikely(!up->pending)) {
		release_sock(sk);

1064
		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("udp cork app bug 3\n"));
1065 1066 1067
		return -EINVAL;
	}

1068 1069
	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
			     page, offset, size, flags);
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089
	if (ret == -EOPNOTSUPP) {
		release_sock(sk);
		return sock_no_sendpage(sk->sk_socket, page, offset,
					size, flags);
	}
	if (ret < 0) {
		udp_flush_pending_frames(sk);
		goto out;
	}

	up->len += size;
	if (!(up->corkflag || (flags&MSG_MORE)))
		ret = udp_push_pending_frames(sk);
	if (!ret)
		ret = size;
out:
	release_sock(sk);
	return ret;
}

E
Eric Dumazet 已提交
1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110

/**
 *	first_packet_length	- return length of first packet in receive queue
 *	@sk: socket
 *
 *	Drops all bad checksum frames, until a valid one is found.
 *	Returns the length of found skb, or 0 if none is found.
 */
static unsigned int first_packet_length(struct sock *sk)
{
	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
	struct sk_buff *skb;
	unsigned int res;

	__skb_queue_head_init(&list_kill);

	spin_lock_bh(&rcvq->lock);
	while ((skb = skb_peek(rcvq)) != NULL &&
		udp_lib_checksum_complete(skb)) {
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
				 IS_UDPLITE(sk));
E
Eric Dumazet 已提交
1111
		atomic_inc(&sk->sk_drops);
E
Eric Dumazet 已提交
1112 1113 1114 1115 1116 1117 1118
		__skb_unlink(skb, rcvq);
		__skb_queue_tail(&list_kill, skb);
	}
	res = skb ? skb->len : 0;
	spin_unlock_bh(&rcvq->lock);

	if (!skb_queue_empty(&list_kill)) {
1119 1120
		bool slow = lock_sock_fast(sk);

E
Eric Dumazet 已提交
1121 1122
		__skb_queue_purge(&list_kill);
		sk_mem_reclaim_partial(sk);
1123
		unlock_sock_fast(sk, slow);
E
Eric Dumazet 已提交
1124 1125 1126 1127
	}
	return res;
}

L
Linus Torvalds 已提交
1128 1129 1130
/*
 *	IOCTL requests applicable to the UDP protocol
 */
1131

L
Linus Torvalds 已提交
1132 1133
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
1134 1135
	switch (cmd) {
	case SIOCOUTQ:
L
Linus Torvalds 已提交
1136
	{
1137 1138
		int amount = sk_wmem_alloc_get(sk);

1139 1140
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
1141

1142 1143
	case SIOCINQ:
	{
E
Eric Dumazet 已提交
1144
		unsigned int amount = first_packet_length(sk);
1145

E
Eric Dumazet 已提交
1146
		if (amount)
1147 1148 1149 1150 1151
			/*
			 * We will only return the amount
			 * of this packet since that is all
			 * that will be read.
			 */
E
Eric Dumazet 已提交
1152 1153
			amount -= sizeof(struct udphdr);

1154 1155
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
1156

1157 1158
	default:
		return -ENOIOCTLCMD;
L
Linus Torvalds 已提交
1159
	}
1160 1161

	return 0;
L
Linus Torvalds 已提交
1162
}
E
Eric Dumazet 已提交
1163
EXPORT_SYMBOL(udp_ioctl);
L
Linus Torvalds 已提交
1164

1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175
/*
 * 	This should be easy, if there is something there we
 * 	return it, otherwise we block.
 */

int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
	struct sk_buff *skb;
1176
	unsigned int ulen, copied;
1177
	int peeked, off = 0;
1178 1179
	int err;
	int is_udplite = IS_UDPLITE(sk);
1180
	bool slow;
1181 1182 1183 1184 1185

	/*
	 *	Check any passed addresses
	 */
	if (addr_len)
E
Eric Dumazet 已提交
1186
		*addr_len = sizeof(*sin);
1187 1188 1189 1190 1191 1192

	if (flags & MSG_ERRQUEUE)
		return ip_recv_error(sk, msg, len);

try_again:
	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1193
				  &peeked, &off, &err);
1194 1195 1196 1197
	if (!skb)
		goto out;

	ulen = skb->len - sizeof(struct udphdr);
1198 1199 1200 1201
	copied = len;
	if (copied > ulen)
		copied = ulen;
	else if (copied < ulen)
1202 1203 1204 1205 1206 1207 1208 1209
		msg->msg_flags |= MSG_TRUNC;

	/*
	 * If checksum is needed at all, try to do it while copying the
	 * data.  If the data is truncated, or if we only want a partial
	 * coverage checksum (UDP-Lite), do it before the copy.
	 */

1210
	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1211 1212 1213 1214 1215 1216
		if (udp_lib_checksum_complete(skb))
			goto csum_copy_err;
	}

	if (skb_csum_unnecessary(skb))
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1217
					      msg->msg_iov, copied);
1218
	else {
E
Eric Dumazet 已提交
1219 1220 1221
		err = skb_copy_and_csum_datagram_iovec(skb,
						       sizeof(struct udphdr),
						       msg->msg_iov);
1222 1223 1224 1225 1226

		if (err == -EINVAL)
			goto csum_copy_err;
	}

1227 1228
	if (unlikely(err)) {
		trace_kfree_skb(skb, udp_recvmsg);
1229 1230 1231 1232 1233
		if (!peeked) {
			atomic_inc(&sk->sk_drops);
			UDP_INC_STATS_USER(sock_net(sk),
					   UDP_MIB_INERRORS, is_udplite);
		}
1234
		goto out_free;
1235
	}
1236 1237

	if (!peeked)
1238 1239
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_INDATAGRAMS, is_udplite);
1240

1241
	sock_recv_ts_and_drops(msg, sk, skb);
1242 1243

	/* Copy the address. */
E
Eric Dumazet 已提交
1244
	if (sin) {
1245 1246 1247 1248 1249 1250 1251 1252
		sin->sin_family = AF_INET;
		sin->sin_port = udp_hdr(skb)->source;
		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
	}
	if (inet->cmsg_flags)
		ip_cmsg_recv(msg, skb);

1253
	err = copied;
1254 1255 1256 1257
	if (flags & MSG_TRUNC)
		err = ulen;

out_free:
1258
	skb_free_datagram_locked(sk, skb);
1259 1260 1261 1262
out:
	return err;

csum_copy_err:
1263
	slow = lock_sock_fast(sk);
1264
	if (!skb_kill_datagram(sk, skb, flags))
1265
		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1266
	unlock_sock_fast(sk, slow);
1267 1268 1269

	if (noblock)
		return -EAGAIN;
1270 1271 1272

	/* starting over for a new packet */
	msg->msg_flags &= ~MSG_TRUNC;
1273 1274 1275 1276
	goto try_again;
}


L
Linus Torvalds 已提交
1277 1278 1279 1280 1281 1282
int udp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
	/*
	 *	1003.1g - break association.
	 */
1283

L
Linus Torvalds 已提交
1284
	sk->sk_state = TCP_CLOSE;
E
Eric Dumazet 已提交
1285 1286
	inet->inet_daddr = 0;
	inet->inet_dport = 0;
1287
	sock_rps_reset_rxhash(sk);
L
Linus Torvalds 已提交
1288 1289 1290 1291 1292 1293
	sk->sk_bound_dev_if = 0;
	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
		sk->sk_prot->unhash(sk);
E
Eric Dumazet 已提交
1294
		inet->inet_sport = 0;
L
Linus Torvalds 已提交
1295 1296 1297 1298
	}
	sk_dst_reset(sk);
	return 0;
}
E
Eric Dumazet 已提交
1299
EXPORT_SYMBOL(udp_disconnect);
L
Linus Torvalds 已提交
1300

1301 1302
void udp_lib_unhash(struct sock *sk)
{
1303 1304
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1305 1306 1307 1308 1309
		struct udp_hslot *hslot, *hslot2;

		hslot  = udp_hashslot(udptable, sock_net(sk),
				      udp_sk(sk)->udp_port_hash);
		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1310

1311 1312
		spin_lock_bh(&hslot->lock);
		if (sk_nulls_del_node_init_rcu(sk)) {
E
Eric Dumazet 已提交
1313
			hslot->count--;
E
Eric Dumazet 已提交
1314
			inet_sk(sk)->inet_num = 0;
1315
			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1316 1317 1318 1319 1320

			spin_lock(&hslot2->lock);
			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
			hslot2->count--;
			spin_unlock(&hslot2->lock);
1321 1322
		}
		spin_unlock_bh(&hslot->lock);
1323 1324 1325 1326
	}
}
EXPORT_SYMBOL(udp_lib_unhash);

E
Eric Dumazet 已提交
1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369
/*
 * inet_rcv_saddr was changed, we must rehash secondary hash
 */
void udp_lib_rehash(struct sock *sk, u16 newhash)
{
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
		struct udp_hslot *hslot, *hslot2, *nhslot2;

		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
		nhslot2 = udp_hashslot2(udptable, newhash);
		udp_sk(sk)->udp_portaddr_hash = newhash;
		if (hslot2 != nhslot2) {
			hslot = udp_hashslot(udptable, sock_net(sk),
					     udp_sk(sk)->udp_port_hash);
			/* we must lock primary chain too */
			spin_lock_bh(&hslot->lock);

			spin_lock(&hslot2->lock);
			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
			hslot2->count--;
			spin_unlock(&hslot2->lock);

			spin_lock(&nhslot2->lock);
			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
						 &nhslot2->head);
			nhslot2->count++;
			spin_unlock(&nhslot2->lock);

			spin_unlock_bh(&hslot->lock);
		}
	}
}
EXPORT_SYMBOL(udp_lib_rehash);

static void udp_v4_rehash(struct sock *sk)
{
	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
					  inet_sk(sk)->inet_rcv_saddr,
					  inet_sk(sk)->inet_num);
	udp_lib_rehash(sk, new_hash);
}

H
Herbert Xu 已提交
1370 1371
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
T
Tom Herbert 已提交
1372
	int rc;
E
Eric Dumazet 已提交
1373

T
Tom Herbert 已提交
1374
	if (inet_sk(sk)->inet_daddr)
1375
		sock_rps_save_rxhash(sk, skb);
T
Tom Herbert 已提交
1376

1377
	rc = sock_queue_rcv_skb(sk, skb);
E
Eric Dumazet 已提交
1378 1379
	if (rc < 0) {
		int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
1380 1381

		/* Note that an ENOMEM error is charged twice */
E
Eric Dumazet 已提交
1382
		if (rc == -ENOMEM)
H
Herbert Xu 已提交
1383 1384
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 is_udplite);
E
Eric Dumazet 已提交
1385 1386
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
		kfree_skb(skb);
1387
		trace_udp_fail_queue_rcv_skb(rc, sk);
E
Eric Dumazet 已提交
1388
		return -1;
H
Herbert Xu 已提交
1389 1390 1391 1392 1393 1394
	}

	return 0;

}

1395 1396 1397 1398 1399 1400 1401 1402
static struct static_key udp_encap_needed __read_mostly;
void udp_encap_enable(void)
{
	if (!static_key_enabled(&udp_encap_needed))
		static_key_slow_inc(&udp_encap_needed);
}
EXPORT_SYMBOL(udp_encap_enable);

1403 1404 1405 1406 1407 1408 1409 1410
/* returns:
 *  -1: error
 *   0: success
 *  >0: "udp encap" protocol resubmission
 *
 * Note that in the success and error cases, the skb is assumed to
 * have either been requeued or freed.
 */
E
Eric Dumazet 已提交
1411
int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
{
	struct udp_sock *up = udp_sk(sk);
	int rc;
	int is_udplite = IS_UDPLITE(sk);

	/*
	 *	Charge it to the socket, dropping if the queue is full.
	 */
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto drop;
	nf_reset(skb);

1424
	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1425 1426
		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);

1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438
		/*
		 * This is an encapsulation socket so pass the skb to
		 * the socket's udp_encap_rcv() hook. Otherwise, just
		 * fall through and pass this up the UDP socket.
		 * up->encap_rcv() returns the following value:
		 * =0 if skb was successfully passed to the encap
		 *    handler or was discarded by it.
		 * >0 if skb should be passed on to UDP.
		 * <0 if skb should be resubmitted as proto -N
		 */

		/* if we're overly short, let UDP handle it */
1439 1440
		encap_rcv = ACCESS_ONCE(up->encap_rcv);
		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1441 1442
			int ret;

1443
			ret = encap_rcv(sk, skb);
1444
			if (ret <= 0) {
1445 1446
				UDP_INC_STATS_BH(sock_net(sk),
						 UDP_MIB_INDATAGRAMS,
1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
						 is_udplite);
				return -ret;
			}
		}

		/* FALLTHROUGH -- it's a UDP Packet */
	}

	/*
	 * 	UDP-Lite specific tests, ignored on UDP sockets
	 */
	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {

		/*
		 * MIB statistics other than incrementing the error count are
		 * disabled for the following two types of errors: these depend
		 * on the application settings, not on the functioning of the
		 * protocol stack as such.
		 *
		 * RFC 3828 here recommends (sec 3.3): "There should also be a
		 * way ... to ... at least let the receiving application block
		 * delivery of packets with coverage values less than a value
		 * provided by the application."
		 */
		if (up->pcrlen == 0) {          /* full coverage was set  */
1472 1473
			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: partial coverage %d while full coverage %d requested\n",
				       UDP_SKB_CB(skb)->cscov, skb->len);
1474 1475 1476 1477 1478 1479 1480 1481 1482
			goto drop;
		}
		/* The next case involves violating the min. coverage requested
		 * by the receiver. This is subtle: if receiver wants x and x is
		 * greater than the buffersize/MTU then receiver will complain
		 * that it wants x while sender emits packets of smaller size y.
		 * Therefore the above ...()->partial_cov statement is essential.
		 */
		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1483 1484
			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: coverage %d too small, need min %d\n",
				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
1485 1486 1487 1488
			goto drop;
		}
	}

1489 1490 1491
	if (rcu_access_pointer(sk->sk_filter) &&
	    udp_lib_checksum_complete(skb))
		goto drop;
1492

1493

1494
	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
1495 1496
		goto drop;

H
Herbert Xu 已提交
1497
	rc = 0;
1498

1499
	ipv4_pktinfo_prepare(skb);
H
Herbert Xu 已提交
1500 1501 1502
	bh_lock_sock(sk);
	if (!sock_owned_by_user(sk))
		rc = __udp_queue_rcv_skb(sk, skb);
1503
	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
Z
Zhu Yi 已提交
1504 1505 1506
		bh_unlock_sock(sk);
		goto drop;
	}
H
Herbert Xu 已提交
1507 1508 1509
	bh_unlock_sock(sk);

	return rc;
1510 1511

drop:
1512
	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
E
Eric Dumazet 已提交
1513
	atomic_inc(&sk->sk_drops);
1514 1515 1516 1517
	kfree_skb(skb);
	return -1;
}

1518 1519 1520 1521 1522 1523

static void flush_stack(struct sock **stack, unsigned int count,
			struct sk_buff *skb, unsigned int final)
{
	unsigned int i;
	struct sk_buff *skb1 = NULL;
1524
	struct sock *sk;
1525 1526

	for (i = 0; i < count; i++) {
1527
		sk = stack[i];
1528 1529 1530
		if (likely(skb1 == NULL))
			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);

1531 1532 1533 1534 1535 1536 1537 1538 1539
		if (!skb1) {
			atomic_inc(&sk->sk_drops);
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 IS_UDPLITE(sk));
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
					 IS_UDPLITE(sk));
		}

		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1540 1541 1542 1543 1544 1545
			skb1 = NULL;
	}
	if (unlikely(skb1))
		kfree_skb(skb1);
}

1546 1547 1548
/*
 *	Multicasts and broadcasts go to each listener.
 *
1549
 *	Note: called only from the BH handler context.
1550
 */
1551
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1552 1553
				    struct udphdr  *uh,
				    __be32 saddr, __be32 daddr,
1554
				    struct udp_table *udptable)
1555
{
1556
	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1557
	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1558
	int dif;
1559
	unsigned int i, count = 0;
1560

1561
	spin_lock(&hslot->lock);
1562
	sk = sk_nulls_head(&hslot->head);
1563
	dif = skb->dev->ifindex;
1564
	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581
	while (sk) {
		stack[count++] = sk;
		sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
				       daddr, uh->source, saddr, dif);
		if (unlikely(count == ARRAY_SIZE(stack))) {
			if (!sk)
				break;
			flush_stack(stack, count, skb, ~0);
			count = 0;
		}
	}
	/*
	 * before releasing chain lock, we must take a reference on sockets
	 */
	for (i = 0; i < count; i++)
		sock_hold(stack[i]);

1582
	spin_unlock(&hslot->lock);
1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594

	/*
	 * do the slow work with no lock held
	 */
	if (count) {
		flush_stack(stack, count, skb, count - 1);

		for (i = 0; i < count; i++)
			sock_put(stack[i]);
	} else {
		kfree_skb(skb);
	}
1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621
	return 0;
}

/* Initialize UDP checksum. If exited with zero value (success),
 * CHECKSUM_UNNECESSARY means, that no more checks are required.
 * Otherwise, csum completion requires chacksumming packet body,
 * including udp header and folding it to skb->csum.
 */
static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
				 int proto)
{
	const struct iphdr *iph;
	int err;

	UDP_SKB_CB(skb)->partial_cov = 0;
	UDP_SKB_CB(skb)->cscov = skb->len;

	if (proto == IPPROTO_UDPLITE) {
		err = udplite_checksum_init(skb, uh);
		if (err)
			return err;
	}

	iph = ip_hdr(skb);
	if (uh->check == 0) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
E
Eric Dumazet 已提交
1622
		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639
				      proto, skb->csum))
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}
	if (!skb_csum_unnecessary(skb))
		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
					       skb->len, proto, 0);
	/* Probably, we should checksum udp header (it should be in cache
	 * in any case) and data in tiny packets (< rx copybreak).
	 */

	return 0;
}

/*
 *	All we need to do is get the socket, and then do a checksum.
 */

1640
int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1641 1642 1643
		   int proto)
{
	struct sock *sk;
1644
	struct udphdr *uh;
1645
	unsigned short ulen;
E
Eric Dumazet 已提交
1646
	struct rtable *rt = skb_rtable(skb);
1647
	__be32 saddr, daddr;
1648
	struct net *net = dev_net(skb->dev);
1649 1650 1651 1652 1653 1654 1655

	/*
	 *  Validate the packet.
	 */
	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
		goto drop;		/* No space for header. */

1656
	uh   = udp_hdr(skb);
1657
	ulen = ntohs(uh->len);
1658 1659 1660
	saddr = ip_hdr(skb)->saddr;
	daddr = ip_hdr(skb)->daddr;

1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674
	if (ulen > skb->len)
		goto short_packet;

	if (proto == IPPROTO_UDP) {
		/* UDP validates ulen. */
		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
			goto short_packet;
		uh = udp_hdr(skb);
	}

	if (udp4_csum_init(skb, uh, proto))
		goto csum_error;

	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1675 1676
		return __udp4_lib_mcast_deliver(net, skb, uh,
				saddr, daddr, udptable);
1677

1678
	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1679 1680

	if (sk != NULL) {
H
Herbert Xu 已提交
1681
		int ret = udp_queue_rcv_skb(sk, skb);
1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699
		sock_put(sk);

		/* a return value > 0 means to resubmit the input, but
		 * it wants the return to be -protocol, or 0
		 */
		if (ret > 0)
			return -ret;
		return 0;
	}

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto drop;
	nf_reset(skb);

	/* No socket. Drop packet silently, if checksum is wrong */
	if (udp_lib_checksum_complete(skb))
		goto csum_error;

1700
	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1701 1702 1703 1704 1705 1706 1707 1708 1709 1710
	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	/*
	 * Hmm.  We got an UDP packet to a port to which we
	 * don't wanna listen.  Ignore it.
	 */
	kfree_skb(skb);
	return 0;

short_packet:
1711
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1712 1713 1714 1715
		       proto == IPPROTO_UDPLITE ? "Lite" : "",
		       &saddr, ntohs(uh->source),
		       ulen, skb->len,
		       &daddr, ntohs(uh->dest));
1716 1717 1718 1719 1720 1721 1722
	goto drop;

csum_error:
	/*
	 * RFC1122: OK.  Discards the bad packet silently (as far as
	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
	 */
1723
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1724 1725
		       proto == IPPROTO_UDPLITE ? "Lite" : "",
		       &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1726 1727
		       ulen);
drop:
1728
	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1729 1730 1731 1732 1733 1734
	kfree_skb(skb);
	return 0;
}

int udp_rcv(struct sk_buff *skb)
{
1735
	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1736 1737
}

1738
void udp_destroy_sock(struct sock *sk)
1739
{
1740
	bool slow = lock_sock_fast(sk);
1741
	udp_flush_pending_frames(sk);
1742
	unlock_sock_fast(sk, slow);
1743 1744
}

L
Linus Torvalds 已提交
1745 1746 1747
/*
 *	Socket option code for UDP
 */
1748
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1749
		       char __user *optval, unsigned int optlen,
1750
		       int (*push_pending_frames)(struct sock *))
L
Linus Torvalds 已提交
1751 1752 1753 1754
{
	struct udp_sock *up = udp_sk(sk);
	int val;
	int err = 0;
W
Wang Chen 已提交
1755
	int is_udplite = IS_UDPLITE(sk);
L
Linus Torvalds 已提交
1756

E
Eric Dumazet 已提交
1757
	if (optlen < sizeof(int))
L
Linus Torvalds 已提交
1758 1759 1760 1761 1762
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

1763
	switch (optname) {
L
Linus Torvalds 已提交
1764 1765 1766 1767 1768 1769
	case UDP_CORK:
		if (val != 0) {
			up->corkflag = 1;
		} else {
			up->corkflag = 0;
			lock_sock(sk);
1770
			(*push_pending_frames)(sk);
L
Linus Torvalds 已提交
1771 1772 1773
			release_sock(sk);
		}
		break;
1774

L
Linus Torvalds 已提交
1775 1776 1777 1778 1779
	case UDP_ENCAP:
		switch (val) {
		case 0:
		case UDP_ENCAP_ESPINUDP:
		case UDP_ENCAP_ESPINUDP_NON_IKE:
1780 1781
			up->encap_rcv = xfrm4_udp_encap_rcv;
			/* FALLTHROUGH */
1782
		case UDP_ENCAP_L2TPINUDP:
L
Linus Torvalds 已提交
1783
			up->encap_type = val;
1784
			udp_encap_enable();
L
Linus Torvalds 已提交
1785 1786 1787 1788 1789 1790 1791
			break;
		default:
			err = -ENOPROTOOPT;
			break;
		}
		break;

1792 1793 1794 1795 1796 1797
	/*
	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
	 */
	/* The sender sets actual checksum coverage length via this option.
	 * The case coverage > packet length is handled by send module. */
	case UDPLITE_SEND_CSCOV:
W
Wang Chen 已提交
1798
		if (!is_udplite)         /* Disable the option on UDP sockets */
1799 1800 1801
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
			val = 8;
1802 1803
		else if (val > USHRT_MAX)
			val = USHRT_MAX;
1804 1805 1806 1807
		up->pcslen = val;
		up->pcflag |= UDPLITE_SEND_CC;
		break;

1808 1809
	/* The receiver specifies a minimum checksum coverage value. To make
	 * sense, this should be set to at least 8 (as done below). If zero is
1810 1811
	 * used, this again means full checksum coverage.                     */
	case UDPLITE_RECV_CSCOV:
W
Wang Chen 已提交
1812
		if (!is_udplite)         /* Disable the option on UDP sockets */
1813 1814 1815
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
			val = 8;
1816 1817
		else if (val > USHRT_MAX)
			val = USHRT_MAX;
1818 1819 1820 1821
		up->pcrlen = val;
		up->pcflag |= UDPLITE_RECV_CC;
		break;

L
Linus Torvalds 已提交
1822 1823 1824
	default:
		err = -ENOPROTOOPT;
		break;
1825
	}
L
Linus Torvalds 已提交
1826 1827 1828

	return err;
}
E
Eric Dumazet 已提交
1829
EXPORT_SYMBOL(udp_lib_setsockopt);
L
Linus Torvalds 已提交
1830

1831
int udp_setsockopt(struct sock *sk, int level, int optname,
1832
		   char __user *optval, unsigned int optlen)
1833 1834 1835 1836 1837 1838 1839 1840 1841
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_push_pending_frames);
	return ip_setsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1842
			  char __user *optval, unsigned int optlen)
1843 1844 1845 1846 1847 1848 1849 1850
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_push_pending_frames);
	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
}
#endif

1851 1852
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
		       char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
1853 1854 1855 1856
{
	struct udp_sock *up = udp_sk(sk);
	int val, len;

E
Eric Dumazet 已提交
1857
	if (get_user(len, optlen))
L
Linus Torvalds 已提交
1858 1859 1860
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));
1861

1862
	if (len < 0)
L
Linus Torvalds 已提交
1863 1864
		return -EINVAL;

1865
	switch (optname) {
L
Linus Torvalds 已提交
1866 1867 1868 1869 1870 1871 1872 1873
	case UDP_CORK:
		val = up->corkflag;
		break;

	case UDP_ENCAP:
		val = up->encap_type;
		break;

1874 1875 1876 1877 1878 1879 1880 1881 1882 1883
	/* The following two cannot be changed on UDP sockets, the return is
	 * always 0 (which corresponds to the full checksum coverage of UDP). */
	case UDPLITE_SEND_CSCOV:
		val = up->pcslen;
		break;

	case UDPLITE_RECV_CSCOV:
		val = up->pcrlen;
		break;

L
Linus Torvalds 已提交
1884 1885
	default:
		return -ENOPROTOOPT;
1886
	}
L
Linus Torvalds 已提交
1887

1888
	if (put_user(len, optlen))
1889
		return -EFAULT;
E
Eric Dumazet 已提交
1890
	if (copy_to_user(optval, &val, len))
L
Linus Torvalds 已提交
1891
		return -EFAULT;
1892
	return 0;
L
Linus Torvalds 已提交
1893
}
E
Eric Dumazet 已提交
1894
EXPORT_SYMBOL(udp_lib_getsockopt);
L
Linus Torvalds 已提交
1895

1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912
int udp_getsockopt(struct sock *sk, int level, int optname,
		   char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return ip_getsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
int compat_udp_getsockopt(struct sock *sk, int level, int optname,
				 char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
}
#endif
L
Linus Torvalds 已提交
1913 1914 1915 1916 1917 1918
/**
 * 	udp_poll - wait for a UDP event.
 *	@file - file struct
 *	@sock - socket
 *	@wait - poll table
 *
1919
 *	This is same as datagram poll, except for the special case of
L
Linus Torvalds 已提交
1920 1921 1922 1923 1924 1925 1926 1927 1928 1929
 *	blocking sockets. If application is using a blocking fd
 *	and a packet with checksum error is in the queue;
 *	then it could get return from select indicating data available
 *	but then block when reading it. Add special case code
 *	to work around these arguably broken applications.
 */
unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask = datagram_poll(file, sock, wait);
	struct sock *sk = sock->sk;
1930

L
Linus Torvalds 已提交
1931
	/* Check for false positives due to checksum errors */
E
Eric Dumazet 已提交
1932 1933 1934
	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
		mask &= ~(POLLIN | POLLRDNORM);
L
Linus Torvalds 已提交
1935 1936

	return mask;
1937

L
Linus Torvalds 已提交
1938
}
E
Eric Dumazet 已提交
1939
EXPORT_SYMBOL(udp_poll);
L
Linus Torvalds 已提交
1940

1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953
struct proto udp_prot = {
	.name		   = "UDP",
	.owner		   = THIS_MODULE,
	.close		   = udp_lib_close,
	.connect	   = ip4_datagram_connect,
	.disconnect	   = udp_disconnect,
	.ioctl		   = udp_ioctl,
	.destroy	   = udp_destroy_sock,
	.setsockopt	   = udp_setsockopt,
	.getsockopt	   = udp_getsockopt,
	.sendmsg	   = udp_sendmsg,
	.recvmsg	   = udp_recvmsg,
	.sendpage	   = udp_sendpage,
H
Herbert Xu 已提交
1954
	.backlog_rcv	   = __udp_queue_rcv_skb,
1955 1956
	.hash		   = udp_lib_hash,
	.unhash		   = udp_lib_unhash,
E
Eric Dumazet 已提交
1957
	.rehash		   = udp_v4_rehash,
1958 1959 1960 1961 1962 1963
	.get_port	   = udp_v4_get_port,
	.memory_allocated  = &udp_memory_allocated,
	.sysctl_mem	   = sysctl_udp_mem,
	.sysctl_wmem	   = &sysctl_udp_wmem_min,
	.sysctl_rmem	   = &sysctl_udp_rmem_min,
	.obj_size	   = sizeof(struct udp_sock),
1964
	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1965
	.h.udp_table	   = &udp_table,
1966 1967 1968 1969
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_udp_setsockopt,
	.compat_getsockopt = compat_udp_getsockopt,
#endif
1970
	.clear_sk	   = sk_prot_clear_portaddr_nulls,
1971
};
E
Eric Dumazet 已提交
1972
EXPORT_SYMBOL(udp_prot);
L
Linus Torvalds 已提交
1973 1974 1975 1976

/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS

1977
static struct sock *udp_get_first(struct seq_file *seq, int start)
L
Linus Torvalds 已提交
1978 1979 1980
{
	struct sock *sk;
	struct udp_iter_state *state = seq->private;
1981
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1982

1983 1984
	for (state->bucket = start; state->bucket <= state->udp_table->mask;
	     ++state->bucket) {
1985
		struct hlist_nulls_node *node;
1986
		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1987 1988 1989 1990

		if (hlist_nulls_empty(&hslot->head))
			continue;

1991
		spin_lock_bh(&hslot->lock);
1992
		sk_nulls_for_each(sk, node, &hslot->head) {
1993
			if (!net_eq(sock_net(sk), net))
1994
				continue;
L
Linus Torvalds 已提交
1995 1996 1997
			if (sk->sk_family == state->family)
				goto found;
		}
1998
		spin_unlock_bh(&hslot->lock);
L
Linus Torvalds 已提交
1999 2000 2001 2002 2003 2004 2005 2006 2007
	}
	sk = NULL;
found:
	return sk;
}

static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
{
	struct udp_iter_state *state = seq->private;
2008
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2009 2010

	do {
2011
		sk = sk_nulls_next(sk);
2012
	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
L
Linus Torvalds 已提交
2013

2014
	if (!sk) {
2015
		if (state->bucket <= state->udp_table->mask)
2016
			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2017
		return udp_get_first(seq, state->bucket + 1);
L
Linus Torvalds 已提交
2018 2019 2020 2021 2022 2023
	}
	return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
2024
	struct sock *sk = udp_get_first(seq, 0);
L
Linus Torvalds 已提交
2025 2026

	if (sk)
2027
		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
L
Linus Torvalds 已提交
2028 2029 2030 2031 2032 2033
			--pos;
	return pos ? NULL : sk;
}

static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
2034
	struct udp_iter_state *state = seq->private;
2035
	state->bucket = MAX_UDP_PORTS;
2036

2037
	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
2038 2039 2040 2041 2042 2043
}

static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct sock *sk;

2044
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2045 2046 2047 2048 2049 2050 2051 2052 2053 2054
		sk = udp_get_idx(seq, 0);
	else
		sk = udp_get_next(seq, v);

	++*pos;
	return sk;
}

static void udp_seq_stop(struct seq_file *seq, void *v)
{
2055 2056
	struct udp_iter_state *state = seq->private;

2057
	if (state->bucket <= state->udp_table->mask)
2058
		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
L
Linus Torvalds 已提交
2059 2060
}

2061
int udp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2062 2063
{
	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
2064 2065
	struct udp_iter_state *s;
	int err;
2066

2067 2068 2069 2070
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			   sizeof(struct udp_iter_state));
	if (err < 0)
		return err;
2071

2072
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2073
	s->family		= afinfo->family;
2074
	s->udp_table		= afinfo->udp_table;
2075
	return err;
2076
}
2077
EXPORT_SYMBOL(udp_seq_open);
2078

L
Linus Torvalds 已提交
2079
/* ------------------------------------------------------------------------ */
2080
int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2081 2082 2083 2084
{
	struct proc_dir_entry *p;
	int rc = 0;

2085 2086 2087 2088
	afinfo->seq_ops.start		= udp_seq_start;
	afinfo->seq_ops.next		= udp_seq_next;
	afinfo->seq_ops.stop		= udp_seq_stop;

2089
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2090
			     afinfo->seq_fops, afinfo);
2091
	if (!p)
L
Linus Torvalds 已提交
2092 2093 2094
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2095
EXPORT_SYMBOL(udp_proc_register);
L
Linus Torvalds 已提交
2096

2097
void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2098
{
2099
	proc_net_remove(net, afinfo->name);
L
Linus Torvalds 已提交
2100
}
E
Eric Dumazet 已提交
2101
EXPORT_SYMBOL(udp_proc_unregister);
2102 2103

/* ------------------------------------------------------------------------ */
2104 2105
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
		int bucket, int *len)
2106 2107
{
	struct inet_sock *inet = inet_sk(sp);
E
Eric Dumazet 已提交
2108 2109 2110 2111
	__be32 dest = inet->inet_daddr;
	__be32 src  = inet->inet_rcv_saddr;
	__u16 destp	  = ntohs(inet->inet_dport);
	__u16 srcp	  = ntohs(inet->inet_sport);
2112

2113
	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
D
Dan Rosenberg 已提交
2114
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
2115
		bucket, src, srcp, dest, destp, sp->sk_state,
2116 2117
		sk_wmem_alloc_get(sp),
		sk_rmem_alloc_get(sp),
2118 2119 2120
		0, 0L, 0,
		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
		0, sock_i_ino(sp),
E
Eric Dumazet 已提交
2121 2122
		atomic_read(&sp->sk_refcnt), sp,
		atomic_read(&sp->sk_drops), len);
2123 2124 2125 2126 2127 2128 2129 2130
}

int udp4_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "%-127s\n",
			   "  sl  local_address rem_address   st tx_queue "
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
E
Eric Dumazet 已提交
2131
			   "inode ref pointer drops");
2132 2133
	else {
		struct udp_iter_state *state = seq->private;
2134
		int len;
2135

2136
		udp4_format_sock(v, seq, state->bucket, &len);
E
Eric Dumazet 已提交
2137
		seq_printf(seq, "%*s\n", 127 - len, "");
2138 2139 2140 2141
	}
	return 0;
}

2142 2143 2144 2145 2146 2147 2148 2149
static const struct file_operations udp_afinfo_seq_fops = {
	.owner    = THIS_MODULE,
	.open     = udp_seq_open,
	.read     = seq_read,
	.llseek   = seq_lseek,
	.release  = seq_release_net
};

2150 2151 2152 2153
/* ------------------------------------------------------------------------ */
static struct udp_seq_afinfo udp4_seq_afinfo = {
	.name		= "udp",
	.family		= AF_INET,
2154
	.udp_table	= &udp_table,
2155
	.seq_fops	= &udp_afinfo_seq_fops,
2156 2157 2158
	.seq_ops	= {
		.show		= udp4_seq_show,
	},
2159 2160
};

2161
static int __net_init udp4_proc_init_net(struct net *net)
2162 2163 2164 2165
{
	return udp_proc_register(net, &udp4_seq_afinfo);
}

2166
static void __net_exit udp4_proc_exit_net(struct net *net)
2167 2168 2169 2170 2171 2172 2173 2174 2175
{
	udp_proc_unregister(net, &udp4_seq_afinfo);
}

static struct pernet_operations udp4_net_ops = {
	.init = udp4_proc_init_net,
	.exit = udp4_proc_exit_net,
};

2176 2177
int __init udp4_proc_init(void)
{
2178
	return register_pernet_subsys(&udp4_net_ops);
2179 2180 2181 2182
}

void udp4_proc_exit(void)
{
2183
	unregister_pernet_subsys(&udp4_net_ops);
2184
}
L
Linus Torvalds 已提交
2185 2186
#endif /* CONFIG_PROC_FS */

2187 2188
static __initdata unsigned long uhash_entries;
static int __init set_uhash_entries(char *str)
2189
{
2190 2191
	ssize_t ret;

2192 2193
	if (!str)
		return 0;
2194 2195 2196 2197 2198

	ret = kstrtoul(str, 0, &uhash_entries);
	if (ret)
		return 0;

2199 2200 2201 2202 2203
	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
		uhash_entries = UDP_HTABLE_SIZE_MIN;
	return 1;
}
__setup("uhash_entries=", set_uhash_entries);
2204

2205 2206 2207 2208
void __init udp_table_init(struct udp_table *table, const char *name)
{
	unsigned int i;

2209 2210 2211 2212 2213 2214 2215 2216 2217 2218
	table->hash = alloc_large_system_hash(name,
					      2 * sizeof(struct udp_hslot),
					      uhash_entries,
					      21, /* one slot per 2 MB */
					      0,
					      &table->log,
					      &table->mask,
					      UDP_HTABLE_SIZE_MIN,
					      64 * 1024);

2219
	table->hash2 = table->hash + (table->mask + 1);
2220
	for (i = 0; i <= table->mask; i++) {
2221
		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
E
Eric Dumazet 已提交
2222
		table->hash[i].count = 0;
2223 2224
		spin_lock_init(&table->hash[i].lock);
	}
2225 2226 2227 2228 2229
	for (i = 0; i <= table->mask; i++) {
		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
		table->hash2[i].count = 0;
		spin_lock_init(&table->hash2[i].lock);
	}
2230 2231
}

H
Hideo Aoki 已提交
2232 2233
void __init udp_init(void)
{
2234
	unsigned long limit;
H
Hideo Aoki 已提交
2235

2236
	udp_table_init(&udp_table, "UDP");
2237
	limit = nr_free_buffer_pages() / 8;
H
Hideo Aoki 已提交
2238 2239 2240 2241 2242 2243 2244 2245 2246
	limit = max(limit, 128UL);
	sysctl_udp_mem[0] = limit / 4 * 3;
	sysctl_udp_mem[1] = limit;
	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;

	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
}

2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265
int udp4_ufo_send_check(struct sk_buff *skb)
{
	const struct iphdr *iph;
	struct udphdr *uh;

	if (!pskb_may_pull(skb, sizeof(*uh)))
		return -EINVAL;

	iph = ip_hdr(skb);
	uh = udp_hdr(skb);

	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
				       IPPROTO_UDP, 0);
	skb->csum_start = skb_transport_header(skb) - skb->head;
	skb->csum_offset = offsetof(struct udphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;
	return 0;
}

2266 2267
struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
	netdev_features_t features)
2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	unsigned int mss;
	int offset;
	__wsum csum;

	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
			     !(type & (SKB_GSO_UDP))))
			goto out;

		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);

		segs = NULL;
		goto out;
	}

	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
	 * do checksum of UDP packets sent as multiple IP fragments.
	 */
2295
	offset = skb_checksum_start_offset(skb);
E
Eric Dumazet 已提交
2296
	csum = skb_checksum(skb, offset, skb->len - offset, 0);
2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308
	offset += skb->csum_offset;
	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
	skb->ip_summed = CHECKSUM_NONE;

	/* Fragment the skb. IP headers of the fragments are updated in
	 * inet_gso_segment()
	 */
	segs = skb_segment(skb, features);
out:
	return segs;
}