xref: /openbmc/linux/net/ipv4/udp.c (revision e23feb16)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		The User Datagram Protocol (UDP).
7  *
8  * Authors:	Ross Biro
9  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10  *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
11  *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
12  *		Hirokazu Takahashi, <taka@valinux.co.jp>
13  *
14  * Fixes:
15  *		Alan Cox	:	verify_area() calls
16  *		Alan Cox	: 	stopped close while in use off icmp
17  *					messages. Not a fix but a botch that
18  *					for udp at least is 'valid'.
19  *		Alan Cox	:	Fixed icmp handling properly
20  *		Alan Cox	: 	Correct error for oversized datagrams
21  *		Alan Cox	:	Tidied select() semantics.
22  *		Alan Cox	:	udp_err() fixed properly, also now
23  *					select and read wake correctly on errors
24  *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
25  *		Alan Cox	:	UDP can count its memory
26  *		Alan Cox	:	send to an unknown connection causes
27  *					an ECONNREFUSED off the icmp, but
28  *					does NOT close.
29  *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
30  *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
31  *					bug no longer crashes it.
32  *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
33  *		Alan Cox	:	Uses skb_free_datagram
34  *		Alan Cox	:	Added get/set sockopt support.
35  *		Alan Cox	:	Broadcasting without option set returns EACCES.
36  *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
37  *		Alan Cox	:	Use ip_tos and ip_ttl
38  *		Alan Cox	:	SNMP Mibs
39  *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
40  *		Matt Dillon	:	UDP length checks.
41  *		Alan Cox	:	Smarter af_inet used properly.
42  *		Alan Cox	:	Use new kernel side addressing.
43  *		Alan Cox	:	Incorrect return on truncated datagram receive.
44  *	Arnt Gulbrandsen 	:	New udp_send and stuff
45  *		Alan Cox	:	Cache last socket
46  *		Alan Cox	:	Route cache
47  *		Jon Peatfield	:	Minor efficiency fix to sendto().
48  *		Mike Shaver	:	RFC1122 checks.
49  *		Alan Cox	:	Nonblocking error fix.
50  *	Willy Konynenberg	:	Transparent proxying support.
51  *		Mike McLagan	:	Routing by source
52  *		David S. Miller	:	New socket lookup architecture.
53  *					Last socket cache retained as it
54  *					does have a high hit rate.
55  *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
56  *		Andi Kleen	:	Some cleanups, cache destination entry
57  *					for connect.
58  *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
59  *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
60  *					return ENOTCONN for unconnected sockets (POSIX)
61  *		Janos Farkas	:	don't deliver multi/broadcasts to a different
62  *					bound-to-device socket
63  *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
64  *					datagrams.
65  *	Hirokazu Takahashi	:	sendfile() on UDP works now.
66  *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
67  *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
68  *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
69  *					a single port at the same time.
70  *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
71  *	James Chapman		:	Add L2TP encapsulation type.
72  *
73  *
74  *		This program is free software; you can redistribute it and/or
75  *		modify it under the terms of the GNU General Public License
76  *		as published by the Free Software Foundation; either version
77  *		2 of the License, or (at your option) any later version.
78  */
79 
80 #define pr_fmt(fmt) "UDP: " fmt
81 
82 #include <asm/uaccess.h>
83 #include <asm/ioctls.h>
84 #include <linux/bootmem.h>
85 #include <linux/highmem.h>
86 #include <linux/swap.h>
87 #include <linux/types.h>
88 #include <linux/fcntl.h>
89 #include <linux/module.h>
90 #include <linux/socket.h>
91 #include <linux/sockios.h>
92 #include <linux/igmp.h>
93 #include <linux/in.h>
94 #include <linux/errno.h>
95 #include <linux/timer.h>
96 #include <linux/mm.h>
97 #include <linux/inet.h>
98 #include <linux/netdevice.h>
99 #include <linux/slab.h>
100 #include <net/tcp_states.h>
101 #include <linux/skbuff.h>
102 #include <linux/proc_fs.h>
103 #include <linux/seq_file.h>
104 #include <net/net_namespace.h>
105 #include <net/icmp.h>
106 #include <net/route.h>
107 #include <net/checksum.h>
108 #include <net/xfrm.h>
109 #include <trace/events/udp.h>
110 #include <linux/static_key.h>
111 #include <trace/events/skb.h>
112 #include <net/busy_poll.h>
113 #include "udp_impl.h"
114 
115 struct udp_table udp_table __read_mostly;
116 EXPORT_SYMBOL(udp_table);
117 
118 long sysctl_udp_mem[3] __read_mostly;
119 EXPORT_SYMBOL(sysctl_udp_mem);
120 
121 int sysctl_udp_rmem_min __read_mostly;
122 EXPORT_SYMBOL(sysctl_udp_rmem_min);
123 
124 int sysctl_udp_wmem_min __read_mostly;
125 EXPORT_SYMBOL(sysctl_udp_wmem_min);
126 
127 atomic_long_t udp_memory_allocated;
128 EXPORT_SYMBOL(udp_memory_allocated);
129 
130 #define MAX_UDP_PORTS 65536
131 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
132 
133 static int udp_lib_lport_inuse(struct net *net, __u16 num,
134 			       const struct udp_hslot *hslot,
135 			       unsigned long *bitmap,
136 			       struct sock *sk,
137 			       int (*saddr_comp)(const struct sock *sk1,
138 						 const struct sock *sk2),
139 			       unsigned int log)
140 {
141 	struct sock *sk2;
142 	struct hlist_nulls_node *node;
143 	kuid_t uid = sock_i_uid(sk);
144 
145 	sk_nulls_for_each(sk2, node, &hslot->head)
146 		if (net_eq(sock_net(sk2), net) &&
147 		    sk2 != sk &&
148 		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
149 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
150 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
151 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
152 		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
153 		      !uid_eq(uid, sock_i_uid(sk2))) &&
154 		    (*saddr_comp)(sk, sk2)) {
155 			if (bitmap)
156 				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
157 					  bitmap);
158 			else
159 				return 1;
160 		}
161 	return 0;
162 }
163 
164 /*
165  * Note: we still hold spinlock of primary hash chain, so no other writer
166  * can insert/delete a socket with local_port == num
167  */
168 static int udp_lib_lport_inuse2(struct net *net, __u16 num,
169 			       struct udp_hslot *hslot2,
170 			       struct sock *sk,
171 			       int (*saddr_comp)(const struct sock *sk1,
172 						 const struct sock *sk2))
173 {
174 	struct sock *sk2;
175 	struct hlist_nulls_node *node;
176 	kuid_t uid = sock_i_uid(sk);
177 	int res = 0;
178 
179 	spin_lock(&hslot2->lock);
180 	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
181 		if (net_eq(sock_net(sk2), net) &&
182 		    sk2 != sk &&
183 		    (udp_sk(sk2)->udp_port_hash == num) &&
184 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
185 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
186 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
187 		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
188 		      !uid_eq(uid, sock_i_uid(sk2))) &&
189 		    (*saddr_comp)(sk, sk2)) {
190 			res = 1;
191 			break;
192 		}
193 	spin_unlock(&hslot2->lock);
194 	return res;
195 }
196 
197 /**
198  *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
199  *
200  *  @sk:          socket struct in question
201  *  @snum:        port number to look up
202  *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
203  *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
204  *                   with NULL address
205  */
206 int udp_lib_get_port(struct sock *sk, unsigned short snum,
207 		       int (*saddr_comp)(const struct sock *sk1,
208 					 const struct sock *sk2),
209 		     unsigned int hash2_nulladdr)
210 {
211 	struct udp_hslot *hslot, *hslot2;
212 	struct udp_table *udptable = sk->sk_prot->h.udp_table;
213 	int    error = 1;
214 	struct net *net = sock_net(sk);
215 
216 	if (!snum) {
217 		int low, high, remaining;
218 		unsigned int rand;
219 		unsigned short first, last;
220 		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
221 
222 		inet_get_local_port_range(&low, &high);
223 		remaining = (high - low) + 1;
224 
225 		rand = net_random();
226 		first = (((u64)rand * remaining) >> 32) + low;
227 		/*
228 		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
229 		 */
230 		rand = (rand | 1) * (udptable->mask + 1);
231 		last = first + udptable->mask + 1;
232 		do {
233 			hslot = udp_hashslot(udptable, net, first);
234 			bitmap_zero(bitmap, PORTS_PER_CHAIN);
235 			spin_lock_bh(&hslot->lock);
236 			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
237 					    saddr_comp, udptable->log);
238 
239 			snum = first;
240 			/*
241 			 * Iterate on all possible values of snum for this hash.
242 			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
243 			 * give us randomization and full range coverage.
244 			 */
245 			do {
246 				if (low <= snum && snum <= high &&
247 				    !test_bit(snum >> udptable->log, bitmap) &&
248 				    !inet_is_reserved_local_port(snum))
249 					goto found;
250 				snum += rand;
251 			} while (snum != first);
252 			spin_unlock_bh(&hslot->lock);
253 		} while (++first != last);
254 		goto fail;
255 	} else {
256 		hslot = udp_hashslot(udptable, net, snum);
257 		spin_lock_bh(&hslot->lock);
258 		if (hslot->count > 10) {
259 			int exist;
260 			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
261 
262 			slot2          &= udptable->mask;
263 			hash2_nulladdr &= udptable->mask;
264 
265 			hslot2 = udp_hashslot2(udptable, slot2);
266 			if (hslot->count < hslot2->count)
267 				goto scan_primary_hash;
268 
269 			exist = udp_lib_lport_inuse2(net, snum, hslot2,
270 						     sk, saddr_comp);
271 			if (!exist && (hash2_nulladdr != slot2)) {
272 				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
273 				exist = udp_lib_lport_inuse2(net, snum, hslot2,
274 							     sk, saddr_comp);
275 			}
276 			if (exist)
277 				goto fail_unlock;
278 			else
279 				goto found;
280 		}
281 scan_primary_hash:
282 		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
283 					saddr_comp, 0))
284 			goto fail_unlock;
285 	}
286 found:
287 	inet_sk(sk)->inet_num = snum;
288 	udp_sk(sk)->udp_port_hash = snum;
289 	udp_sk(sk)->udp_portaddr_hash ^= snum;
290 	if (sk_unhashed(sk)) {
291 		sk_nulls_add_node_rcu(sk, &hslot->head);
292 		hslot->count++;
293 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
294 
295 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
296 		spin_lock(&hslot2->lock);
297 		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
298 					 &hslot2->head);
299 		hslot2->count++;
300 		spin_unlock(&hslot2->lock);
301 	}
302 	error = 0;
303 fail_unlock:
304 	spin_unlock_bh(&hslot->lock);
305 fail:
306 	return error;
307 }
308 EXPORT_SYMBOL(udp_lib_get_port);
309 
310 static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
311 {
312 	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
313 
314 	return 	(!ipv6_only_sock(sk2)  &&
315 		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
316 		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
317 }
318 
319 static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
320 				       unsigned int port)
321 {
322 	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
323 }
324 
325 int udp_v4_get_port(struct sock *sk, unsigned short snum)
326 {
327 	unsigned int hash2_nulladdr =
328 		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
329 	unsigned int hash2_partial =
330 		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
331 
332 	/* precompute partial secondary hash */
333 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
334 	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
335 }
336 
337 static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
338 			 unsigned short hnum,
339 			 __be16 sport, __be32 daddr, __be16 dport, int dif)
340 {
341 	int score = -1;
342 
343 	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
344 			!ipv6_only_sock(sk)) {
345 		struct inet_sock *inet = inet_sk(sk);
346 
347 		score = (sk->sk_family == PF_INET ? 2 : 1);
348 		if (inet->inet_rcv_saddr) {
349 			if (inet->inet_rcv_saddr != daddr)
350 				return -1;
351 			score += 4;
352 		}
353 		if (inet->inet_daddr) {
354 			if (inet->inet_daddr != saddr)
355 				return -1;
356 			score += 4;
357 		}
358 		if (inet->inet_dport) {
359 			if (inet->inet_dport != sport)
360 				return -1;
361 			score += 4;
362 		}
363 		if (sk->sk_bound_dev_if) {
364 			if (sk->sk_bound_dev_if != dif)
365 				return -1;
366 			score += 4;
367 		}
368 	}
369 	return score;
370 }
371 
372 /*
373  * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
374  */
375 static inline int compute_score2(struct sock *sk, struct net *net,
376 				 __be32 saddr, __be16 sport,
377 				 __be32 daddr, unsigned int hnum, int dif)
378 {
379 	int score = -1;
380 
381 	if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
382 		struct inet_sock *inet = inet_sk(sk);
383 
384 		if (inet->inet_rcv_saddr != daddr)
385 			return -1;
386 		if (inet->inet_num != hnum)
387 			return -1;
388 
389 		score = (sk->sk_family == PF_INET ? 2 : 1);
390 		if (inet->inet_daddr) {
391 			if (inet->inet_daddr != saddr)
392 				return -1;
393 			score += 4;
394 		}
395 		if (inet->inet_dport) {
396 			if (inet->inet_dport != sport)
397 				return -1;
398 			score += 4;
399 		}
400 		if (sk->sk_bound_dev_if) {
401 			if (sk->sk_bound_dev_if != dif)
402 				return -1;
403 			score += 4;
404 		}
405 	}
406 	return score;
407 }
408 
409 
410 /* called with read_rcu_lock() */
411 static struct sock *udp4_lib_lookup2(struct net *net,
412 		__be32 saddr, __be16 sport,
413 		__be32 daddr, unsigned int hnum, int dif,
414 		struct udp_hslot *hslot2, unsigned int slot2)
415 {
416 	struct sock *sk, *result;
417 	struct hlist_nulls_node *node;
418 	int score, badness, matches = 0, reuseport = 0;
419 	u32 hash = 0;
420 
421 begin:
422 	result = NULL;
423 	badness = 0;
424 	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
425 		score = compute_score2(sk, net, saddr, sport,
426 				      daddr, hnum, dif);
427 		if (score > badness) {
428 			result = sk;
429 			badness = score;
430 			reuseport = sk->sk_reuseport;
431 			if (reuseport) {
432 				hash = inet_ehashfn(net, daddr, hnum,
433 						    saddr, sport);
434 				matches = 1;
435 			}
436 		} else if (score == badness && reuseport) {
437 			matches++;
438 			if (((u64)hash * matches) >> 32 == 0)
439 				result = sk;
440 			hash = next_pseudo_random32(hash);
441 		}
442 	}
443 	/*
444 	 * if the nulls value we got at the end of this lookup is
445 	 * not the expected one, we must restart lookup.
446 	 * We probably met an item that was moved to another chain.
447 	 */
448 	if (get_nulls_value(node) != slot2)
449 		goto begin;
450 	if (result) {
451 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
452 			result = NULL;
453 		else if (unlikely(compute_score2(result, net, saddr, sport,
454 				  daddr, hnum, dif) < badness)) {
455 			sock_put(result);
456 			goto begin;
457 		}
458 	}
459 	return result;
460 }
461 
462 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
463  * harder than this. -DaveM
464  */
465 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
466 		__be16 sport, __be32 daddr, __be16 dport,
467 		int dif, struct udp_table *udptable)
468 {
469 	struct sock *sk, *result;
470 	struct hlist_nulls_node *node;
471 	unsigned short hnum = ntohs(dport);
472 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
473 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
474 	int score, badness, matches = 0, reuseport = 0;
475 	u32 hash = 0;
476 
477 	rcu_read_lock();
478 	if (hslot->count > 10) {
479 		hash2 = udp4_portaddr_hash(net, daddr, hnum);
480 		slot2 = hash2 & udptable->mask;
481 		hslot2 = &udptable->hash2[slot2];
482 		if (hslot->count < hslot2->count)
483 			goto begin;
484 
485 		result = udp4_lib_lookup2(net, saddr, sport,
486 					  daddr, hnum, dif,
487 					  hslot2, slot2);
488 		if (!result) {
489 			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
490 			slot2 = hash2 & udptable->mask;
491 			hslot2 = &udptable->hash2[slot2];
492 			if (hslot->count < hslot2->count)
493 				goto begin;
494 
495 			result = udp4_lib_lookup2(net, saddr, sport,
496 						  htonl(INADDR_ANY), hnum, dif,
497 						  hslot2, slot2);
498 		}
499 		rcu_read_unlock();
500 		return result;
501 	}
502 begin:
503 	result = NULL;
504 	badness = 0;
505 	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
506 		score = compute_score(sk, net, saddr, hnum, sport,
507 				      daddr, dport, dif);
508 		if (score > badness) {
509 			result = sk;
510 			badness = score;
511 			reuseport = sk->sk_reuseport;
512 			if (reuseport) {
513 				hash = inet_ehashfn(net, daddr, hnum,
514 						    saddr, sport);
515 				matches = 1;
516 			}
517 		} else if (score == badness && reuseport) {
518 			matches++;
519 			if (((u64)hash * matches) >> 32 == 0)
520 				result = sk;
521 			hash = next_pseudo_random32(hash);
522 		}
523 	}
524 	/*
525 	 * if the nulls value we got at the end of this lookup is
526 	 * not the expected one, we must restart lookup.
527 	 * We probably met an item that was moved to another chain.
528 	 */
529 	if (get_nulls_value(node) != slot)
530 		goto begin;
531 
532 	if (result) {
533 		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
534 			result = NULL;
535 		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
536 				  daddr, dport, dif) < badness)) {
537 			sock_put(result);
538 			goto begin;
539 		}
540 	}
541 	rcu_read_unlock();
542 	return result;
543 }
544 EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
545 
546 static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
547 						 __be16 sport, __be16 dport,
548 						 struct udp_table *udptable)
549 {
550 	struct sock *sk;
551 	const struct iphdr *iph = ip_hdr(skb);
552 
553 	if (unlikely(sk = skb_steal_sock(skb)))
554 		return sk;
555 	else
556 		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
557 					 iph->daddr, dport, inet_iif(skb),
558 					 udptable);
559 }
560 
561 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
562 			     __be32 daddr, __be16 dport, int dif)
563 {
564 	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
565 }
566 EXPORT_SYMBOL_GPL(udp4_lib_lookup);
567 
568 static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
569 					     __be16 loc_port, __be32 loc_addr,
570 					     __be16 rmt_port, __be32 rmt_addr,
571 					     int dif)
572 {
573 	struct hlist_nulls_node *node;
574 	struct sock *s = sk;
575 	unsigned short hnum = ntohs(loc_port);
576 
577 	sk_nulls_for_each_from(s, node) {
578 		struct inet_sock *inet = inet_sk(s);
579 
580 		if (!net_eq(sock_net(s), net) ||
581 		    udp_sk(s)->udp_port_hash != hnum ||
582 		    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
583 		    (inet->inet_dport != rmt_port && inet->inet_dport) ||
584 		    (inet->inet_rcv_saddr &&
585 		     inet->inet_rcv_saddr != loc_addr) ||
586 		    ipv6_only_sock(s) ||
587 		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
588 			continue;
589 		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
590 			continue;
591 		goto found;
592 	}
593 	s = NULL;
594 found:
595 	return s;
596 }
597 
598 /*
599  * This routine is called by the ICMP module when it gets some
600  * sort of error condition.  If err < 0 then the socket should
601  * be closed and the error returned to the user.  If err > 0
602  * it's just the icmp type << 8 | icmp code.
603  * Header points to the ip header of the error packet. We move
604  * on past this. Then (as it used to claim before adjustment)
605  * header points to the first 8 bytes of the udp header.  We need
606  * to find the appropriate port.
607  */
608 
609 void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
610 {
611 	struct inet_sock *inet;
612 	const struct iphdr *iph = (const struct iphdr *)skb->data;
613 	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
614 	const int type = icmp_hdr(skb)->type;
615 	const int code = icmp_hdr(skb)->code;
616 	struct sock *sk;
617 	int harderr;
618 	int err;
619 	struct net *net = dev_net(skb->dev);
620 
621 	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
622 			iph->saddr, uh->source, skb->dev->ifindex, udptable);
623 	if (sk == NULL) {
624 		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
625 		return;	/* No socket for error */
626 	}
627 
628 	err = 0;
629 	harderr = 0;
630 	inet = inet_sk(sk);
631 
632 	switch (type) {
633 	default:
634 	case ICMP_TIME_EXCEEDED:
635 		err = EHOSTUNREACH;
636 		break;
637 	case ICMP_SOURCE_QUENCH:
638 		goto out;
639 	case ICMP_PARAMETERPROB:
640 		err = EPROTO;
641 		harderr = 1;
642 		break;
643 	case ICMP_DEST_UNREACH:
644 		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
645 			ipv4_sk_update_pmtu(skb, sk, info);
646 			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
647 				err = EMSGSIZE;
648 				harderr = 1;
649 				break;
650 			}
651 			goto out;
652 		}
653 		err = EHOSTUNREACH;
654 		if (code <= NR_ICMP_UNREACH) {
655 			harderr = icmp_err_convert[code].fatal;
656 			err = icmp_err_convert[code].errno;
657 		}
658 		break;
659 	case ICMP_REDIRECT:
660 		ipv4_sk_redirect(skb, sk);
661 		goto out;
662 	}
663 
664 	/*
665 	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
666 	 *	4.1.3.3.
667 	 */
668 	if (!inet->recverr) {
669 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
670 			goto out;
671 	} else
672 		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
673 
674 	sk->sk_err = err;
675 	sk->sk_error_report(sk);
676 out:
677 	sock_put(sk);
678 }
679 
680 void udp_err(struct sk_buff *skb, u32 info)
681 {
682 	__udp4_lib_err(skb, info, &udp_table);
683 }
684 
685 /*
686  * Throw away all pending data and cancel the corking. Socket is locked.
687  */
688 void udp_flush_pending_frames(struct sock *sk)
689 {
690 	struct udp_sock *up = udp_sk(sk);
691 
692 	if (up->pending) {
693 		up->len = 0;
694 		up->pending = 0;
695 		ip_flush_pending_frames(sk);
696 	}
697 }
698 EXPORT_SYMBOL(udp_flush_pending_frames);
699 
700 /**
701  * 	udp4_hwcsum  -  handle outgoing HW checksumming
702  * 	@skb: 	sk_buff containing the filled-in UDP header
703  * 	        (checksum field must be zeroed out)
704  *	@src:	source IP address
705  *	@dst:	destination IP address
706  */
707 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
708 {
709 	struct udphdr *uh = udp_hdr(skb);
710 	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
711 	int offset = skb_transport_offset(skb);
712 	int len = skb->len - offset;
713 	int hlen = len;
714 	__wsum csum = 0;
715 
716 	if (!frags) {
717 		/*
718 		 * Only one fragment on the socket.
719 		 */
720 		skb->csum_start = skb_transport_header(skb) - skb->head;
721 		skb->csum_offset = offsetof(struct udphdr, check);
722 		uh->check = ~csum_tcpudp_magic(src, dst, len,
723 					       IPPROTO_UDP, 0);
724 	} else {
725 		/*
726 		 * HW-checksum won't work as there are two or more
727 		 * fragments on the socket so that all csums of sk_buffs
728 		 * should be together
729 		 */
730 		do {
731 			csum = csum_add(csum, frags->csum);
732 			hlen -= frags->len;
733 		} while ((frags = frags->next));
734 
735 		csum = skb_checksum(skb, offset, hlen, csum);
736 		skb->ip_summed = CHECKSUM_NONE;
737 
738 		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
739 		if (uh->check == 0)
740 			uh->check = CSUM_MANGLED_0;
741 	}
742 }
743 EXPORT_SYMBOL_GPL(udp4_hwcsum);
744 
745 static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
746 {
747 	struct sock *sk = skb->sk;
748 	struct inet_sock *inet = inet_sk(sk);
749 	struct udphdr *uh;
750 	int err = 0;
751 	int is_udplite = IS_UDPLITE(sk);
752 	int offset = skb_transport_offset(skb);
753 	int len = skb->len - offset;
754 	__wsum csum = 0;
755 
756 	/*
757 	 * Create a UDP header
758 	 */
759 	uh = udp_hdr(skb);
760 	uh->source = inet->inet_sport;
761 	uh->dest = fl4->fl4_dport;
762 	uh->len = htons(len);
763 	uh->check = 0;
764 
765 	if (is_udplite)  				 /*     UDP-Lite      */
766 		csum = udplite_csum(skb);
767 
768 	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */
769 
770 		skb->ip_summed = CHECKSUM_NONE;
771 		goto send;
772 
773 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
774 
775 		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
776 		goto send;
777 
778 	} else
779 		csum = udp_csum(skb);
780 
781 	/* add protocol-dependent pseudo-header */
782 	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
783 				      sk->sk_protocol, csum);
784 	if (uh->check == 0)
785 		uh->check = CSUM_MANGLED_0;
786 
787 send:
788 	err = ip_send_skb(sock_net(sk), skb);
789 	if (err) {
790 		if (err == -ENOBUFS && !inet->recverr) {
791 			UDP_INC_STATS_USER(sock_net(sk),
792 					   UDP_MIB_SNDBUFERRORS, is_udplite);
793 			err = 0;
794 		}
795 	} else
796 		UDP_INC_STATS_USER(sock_net(sk),
797 				   UDP_MIB_OUTDATAGRAMS, is_udplite);
798 	return err;
799 }
800 
801 /*
802  * Push out all pending data as one UDP datagram. Socket is locked.
803  */
804 int udp_push_pending_frames(struct sock *sk)
805 {
806 	struct udp_sock  *up = udp_sk(sk);
807 	struct inet_sock *inet = inet_sk(sk);
808 	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
809 	struct sk_buff *skb;
810 	int err = 0;
811 
812 	skb = ip_finish_skb(sk, fl4);
813 	if (!skb)
814 		goto out;
815 
816 	err = udp_send_skb(skb, fl4);
817 
818 out:
819 	up->len = 0;
820 	up->pending = 0;
821 	return err;
822 }
823 EXPORT_SYMBOL(udp_push_pending_frames);
824 
825 int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
826 		size_t len)
827 {
828 	struct inet_sock *inet = inet_sk(sk);
829 	struct udp_sock *up = udp_sk(sk);
830 	struct flowi4 fl4_stack;
831 	struct flowi4 *fl4;
832 	int ulen = len;
833 	struct ipcm_cookie ipc;
834 	struct rtable *rt = NULL;
835 	int free = 0;
836 	int connected = 0;
837 	__be32 daddr, faddr, saddr;
838 	__be16 dport;
839 	u8  tos;
840 	int err, is_udplite = IS_UDPLITE(sk);
841 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
842 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
843 	struct sk_buff *skb;
844 	struct ip_options_data opt_copy;
845 
846 	if (len > 0xFFFF)
847 		return -EMSGSIZE;
848 
849 	/*
850 	 *	Check the flags.
851 	 */
852 
853 	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
854 		return -EOPNOTSUPP;
855 
856 	ipc.opt = NULL;
857 	ipc.tx_flags = 0;
858 
859 	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
860 
861 	fl4 = &inet->cork.fl.u.ip4;
862 	if (up->pending) {
863 		/*
864 		 * There are pending frames.
865 		 * The socket lock must be held while it's corked.
866 		 */
867 		lock_sock(sk);
868 		if (likely(up->pending)) {
869 			if (unlikely(up->pending != AF_INET)) {
870 				release_sock(sk);
871 				return -EINVAL;
872 			}
873 			goto do_append_data;
874 		}
875 		release_sock(sk);
876 	}
877 	ulen += sizeof(struct udphdr);
878 
879 	/*
880 	 *	Get and verify the address.
881 	 */
882 	if (msg->msg_name) {
883 		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
884 		if (msg->msg_namelen < sizeof(*usin))
885 			return -EINVAL;
886 		if (usin->sin_family != AF_INET) {
887 			if (usin->sin_family != AF_UNSPEC)
888 				return -EAFNOSUPPORT;
889 		}
890 
891 		daddr = usin->sin_addr.s_addr;
892 		dport = usin->sin_port;
893 		if (dport == 0)
894 			return -EINVAL;
895 	} else {
896 		if (sk->sk_state != TCP_ESTABLISHED)
897 			return -EDESTADDRREQ;
898 		daddr = inet->inet_daddr;
899 		dport = inet->inet_dport;
900 		/* Open fast path for connected socket.
901 		   Route will not be used, if at least one option is set.
902 		 */
903 		connected = 1;
904 	}
905 	ipc.addr = inet->inet_saddr;
906 
907 	ipc.oif = sk->sk_bound_dev_if;
908 
909 	sock_tx_timestamp(sk, &ipc.tx_flags);
910 
911 	if (msg->msg_controllen) {
912 		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
913 		if (err)
914 			return err;
915 		if (ipc.opt)
916 			free = 1;
917 		connected = 0;
918 	}
919 	if (!ipc.opt) {
920 		struct ip_options_rcu *inet_opt;
921 
922 		rcu_read_lock();
923 		inet_opt = rcu_dereference(inet->inet_opt);
924 		if (inet_opt) {
925 			memcpy(&opt_copy, inet_opt,
926 			       sizeof(*inet_opt) + inet_opt->opt.optlen);
927 			ipc.opt = &opt_copy.opt;
928 		}
929 		rcu_read_unlock();
930 	}
931 
932 	saddr = ipc.addr;
933 	ipc.addr = faddr = daddr;
934 
935 	if (ipc.opt && ipc.opt->opt.srr) {
936 		if (!daddr)
937 			return -EINVAL;
938 		faddr = ipc.opt->opt.faddr;
939 		connected = 0;
940 	}
941 	tos = RT_TOS(inet->tos);
942 	if (sock_flag(sk, SOCK_LOCALROUTE) ||
943 	    (msg->msg_flags & MSG_DONTROUTE) ||
944 	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
945 		tos |= RTO_ONLINK;
946 		connected = 0;
947 	}
948 
949 	if (ipv4_is_multicast(daddr)) {
950 		if (!ipc.oif)
951 			ipc.oif = inet->mc_index;
952 		if (!saddr)
953 			saddr = inet->mc_addr;
954 		connected = 0;
955 	} else if (!ipc.oif)
956 		ipc.oif = inet->uc_index;
957 
958 	if (connected)
959 		rt = (struct rtable *)sk_dst_check(sk, 0);
960 
961 	if (rt == NULL) {
962 		struct net *net = sock_net(sk);
963 
964 		fl4 = &fl4_stack;
965 		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
966 				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
967 				   inet_sk_flowi_flags(sk)|FLOWI_FLAG_CAN_SLEEP,
968 				   faddr, saddr, dport, inet->inet_sport);
969 
970 		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
971 		rt = ip_route_output_flow(net, fl4, sk);
972 		if (IS_ERR(rt)) {
973 			err = PTR_ERR(rt);
974 			rt = NULL;
975 			if (err == -ENETUNREACH)
976 				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
977 			goto out;
978 		}
979 
980 		err = -EACCES;
981 		if ((rt->rt_flags & RTCF_BROADCAST) &&
982 		    !sock_flag(sk, SOCK_BROADCAST))
983 			goto out;
984 		if (connected)
985 			sk_dst_set(sk, dst_clone(&rt->dst));
986 	}
987 
988 	if (msg->msg_flags&MSG_CONFIRM)
989 		goto do_confirm;
990 back_from_confirm:
991 
992 	saddr = fl4->saddr;
993 	if (!ipc.addr)
994 		daddr = ipc.addr = fl4->daddr;
995 
996 	/* Lockless fast path for the non-corking case. */
997 	if (!corkreq) {
998 		skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
999 				  sizeof(struct udphdr), &ipc, &rt,
1000 				  msg->msg_flags);
1001 		err = PTR_ERR(skb);
1002 		if (!IS_ERR_OR_NULL(skb))
1003 			err = udp_send_skb(skb, fl4);
1004 		goto out;
1005 	}
1006 
1007 	lock_sock(sk);
1008 	if (unlikely(up->pending)) {
1009 		/* The socket is already corked while preparing it. */
1010 		/* ... which is an evident application bug. --ANK */
1011 		release_sock(sk);
1012 
1013 		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("cork app bug 2\n"));
1014 		err = -EINVAL;
1015 		goto out;
1016 	}
1017 	/*
1018 	 *	Now cork the socket to pend data.
1019 	 */
1020 	fl4 = &inet->cork.fl.u.ip4;
1021 	fl4->daddr = daddr;
1022 	fl4->saddr = saddr;
1023 	fl4->fl4_dport = dport;
1024 	fl4->fl4_sport = inet->inet_sport;
1025 	up->pending = AF_INET;
1026 
1027 do_append_data:
1028 	up->len += ulen;
1029 	err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
1030 			     sizeof(struct udphdr), &ipc, &rt,
1031 			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1032 	if (err)
1033 		udp_flush_pending_frames(sk);
1034 	else if (!corkreq)
1035 		err = udp_push_pending_frames(sk);
1036 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1037 		up->pending = 0;
1038 	release_sock(sk);
1039 
1040 out:
1041 	ip_rt_put(rt);
1042 	if (free)
1043 		kfree(ipc.opt);
1044 	if (!err)
1045 		return len;
1046 	/*
1047 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1048 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1049 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1050 	 * things).  We could add another new stat but at least for now that
1051 	 * seems like overkill.
1052 	 */
1053 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1054 		UDP_INC_STATS_USER(sock_net(sk),
1055 				UDP_MIB_SNDBUFERRORS, is_udplite);
1056 	}
1057 	return err;
1058 
1059 do_confirm:
1060 	dst_confirm(&rt->dst);
1061 	if (!(msg->msg_flags&MSG_PROBE) || len)
1062 		goto back_from_confirm;
1063 	err = 0;
1064 	goto out;
1065 }
1066 EXPORT_SYMBOL(udp_sendmsg);
1067 
1068 int udp_sendpage(struct sock *sk, struct page *page, int offset,
1069 		 size_t size, int flags)
1070 {
1071 	struct inet_sock *inet = inet_sk(sk);
1072 	struct udp_sock *up = udp_sk(sk);
1073 	int ret;
1074 
1075 	if (!up->pending) {
1076 		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
1077 
1078 		/* Call udp_sendmsg to specify destination address which
1079 		 * sendpage interface can't pass.
1080 		 * This will succeed only when the socket is connected.
1081 		 */
1082 		ret = udp_sendmsg(NULL, sk, &msg, 0);
1083 		if (ret < 0)
1084 			return ret;
1085 	}
1086 
1087 	lock_sock(sk);
1088 
1089 	if (unlikely(!up->pending)) {
1090 		release_sock(sk);
1091 
1092 		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("udp cork app bug 3\n"));
1093 		return -EINVAL;
1094 	}
1095 
1096 	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1097 			     page, offset, size, flags);
1098 	if (ret == -EOPNOTSUPP) {
1099 		release_sock(sk);
1100 		return sock_no_sendpage(sk->sk_socket, page, offset,
1101 					size, flags);
1102 	}
1103 	if (ret < 0) {
1104 		udp_flush_pending_frames(sk);
1105 		goto out;
1106 	}
1107 
1108 	up->len += size;
1109 	if (!(up->corkflag || (flags&MSG_MORE)))
1110 		ret = udp_push_pending_frames(sk);
1111 	if (!ret)
1112 		ret = size;
1113 out:
1114 	release_sock(sk);
1115 	return ret;
1116 }
1117 
1118 
1119 /**
1120  *	first_packet_length	- return length of first packet in receive queue
1121  *	@sk: socket
1122  *
1123  *	Drops all bad checksum frames, until a valid one is found.
1124  *	Returns the length of found skb, or 0 if none is found.
1125  */
1126 static unsigned int first_packet_length(struct sock *sk)
1127 {
1128 	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
1129 	struct sk_buff *skb;
1130 	unsigned int res;
1131 
1132 	__skb_queue_head_init(&list_kill);
1133 
1134 	spin_lock_bh(&rcvq->lock);
1135 	while ((skb = skb_peek(rcvq)) != NULL &&
1136 		udp_lib_checksum_complete(skb)) {
1137 		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS,
1138 				 IS_UDPLITE(sk));
1139 		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1140 				 IS_UDPLITE(sk));
1141 		atomic_inc(&sk->sk_drops);
1142 		__skb_unlink(skb, rcvq);
1143 		__skb_queue_tail(&list_kill, skb);
1144 	}
1145 	res = skb ? skb->len : 0;
1146 	spin_unlock_bh(&rcvq->lock);
1147 
1148 	if (!skb_queue_empty(&list_kill)) {
1149 		bool slow = lock_sock_fast(sk);
1150 
1151 		__skb_queue_purge(&list_kill);
1152 		sk_mem_reclaim_partial(sk);
1153 		unlock_sock_fast(sk, slow);
1154 	}
1155 	return res;
1156 }
1157 
1158 /*
1159  *	IOCTL requests applicable to the UDP protocol
1160  */
1161 
1162 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1163 {
1164 	switch (cmd) {
1165 	case SIOCOUTQ:
1166 	{
1167 		int amount = sk_wmem_alloc_get(sk);
1168 
1169 		return put_user(amount, (int __user *)arg);
1170 	}
1171 
1172 	case SIOCINQ:
1173 	{
1174 		unsigned int amount = first_packet_length(sk);
1175 
1176 		if (amount)
1177 			/*
1178 			 * We will only return the amount
1179 			 * of this packet since that is all
1180 			 * that will be read.
1181 			 */
1182 			amount -= sizeof(struct udphdr);
1183 
1184 		return put_user(amount, (int __user *)arg);
1185 	}
1186 
1187 	default:
1188 		return -ENOIOCTLCMD;
1189 	}
1190 
1191 	return 0;
1192 }
1193 EXPORT_SYMBOL(udp_ioctl);
1194 
1195 /*
1196  * 	This should be easy, if there is something there we
1197  * 	return it, otherwise we block.
1198  */
1199 
1200 int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1201 		size_t len, int noblock, int flags, int *addr_len)
1202 {
1203 	struct inet_sock *inet = inet_sk(sk);
1204 	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
1205 	struct sk_buff *skb;
1206 	unsigned int ulen, copied;
1207 	int peeked, off = 0;
1208 	int err;
1209 	int is_udplite = IS_UDPLITE(sk);
1210 	bool slow;
1211 
1212 	/*
1213 	 *	Check any passed addresses
1214 	 */
1215 	if (addr_len)
1216 		*addr_len = sizeof(*sin);
1217 
1218 	if (flags & MSG_ERRQUEUE)
1219 		return ip_recv_error(sk, msg, len);
1220 
1221 try_again:
1222 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1223 				  &peeked, &off, &err);
1224 	if (!skb)
1225 		goto out;
1226 
1227 	ulen = skb->len - sizeof(struct udphdr);
1228 	copied = len;
1229 	if (copied > ulen)
1230 		copied = ulen;
1231 	else if (copied < ulen)
1232 		msg->msg_flags |= MSG_TRUNC;
1233 
1234 	/*
1235 	 * If checksum is needed at all, try to do it while copying the
1236 	 * data.  If the data is truncated, or if we only want a partial
1237 	 * coverage checksum (UDP-Lite), do it before the copy.
1238 	 */
1239 
1240 	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1241 		if (udp_lib_checksum_complete(skb))
1242 			goto csum_copy_err;
1243 	}
1244 
1245 	if (skb_csum_unnecessary(skb))
1246 		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1247 					      msg->msg_iov, copied);
1248 	else {
1249 		err = skb_copy_and_csum_datagram_iovec(skb,
1250 						       sizeof(struct udphdr),
1251 						       msg->msg_iov);
1252 
1253 		if (err == -EINVAL)
1254 			goto csum_copy_err;
1255 	}
1256 
1257 	if (unlikely(err)) {
1258 		trace_kfree_skb(skb, udp_recvmsg);
1259 		if (!peeked) {
1260 			atomic_inc(&sk->sk_drops);
1261 			UDP_INC_STATS_USER(sock_net(sk),
1262 					   UDP_MIB_INERRORS, is_udplite);
1263 		}
1264 		goto out_free;
1265 	}
1266 
1267 	if (!peeked)
1268 		UDP_INC_STATS_USER(sock_net(sk),
1269 				UDP_MIB_INDATAGRAMS, is_udplite);
1270 
1271 	sock_recv_ts_and_drops(msg, sk, skb);
1272 
1273 	/* Copy the address. */
1274 	if (sin) {
1275 		sin->sin_family = AF_INET;
1276 		sin->sin_port = udp_hdr(skb)->source;
1277 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1278 		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1279 	}
1280 	if (inet->cmsg_flags)
1281 		ip_cmsg_recv(msg, skb);
1282 
1283 	err = copied;
1284 	if (flags & MSG_TRUNC)
1285 		err = ulen;
1286 
1287 out_free:
1288 	skb_free_datagram_locked(sk, skb);
1289 out:
1290 	return err;
1291 
1292 csum_copy_err:
1293 	slow = lock_sock_fast(sk);
1294 	if (!skb_kill_datagram(sk, skb, flags)) {
1295 		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1296 		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1297 	}
1298 	unlock_sock_fast(sk, slow);
1299 
1300 	if (noblock)
1301 		return -EAGAIN;
1302 
1303 	/* starting over for a new packet */
1304 	msg->msg_flags &= ~MSG_TRUNC;
1305 	goto try_again;
1306 }
1307 
1308 
1309 int udp_disconnect(struct sock *sk, int flags)
1310 {
1311 	struct inet_sock *inet = inet_sk(sk);
1312 	/*
1313 	 *	1003.1g - break association.
1314 	 */
1315 
1316 	sk->sk_state = TCP_CLOSE;
1317 	inet->inet_daddr = 0;
1318 	inet->inet_dport = 0;
1319 	sock_rps_reset_rxhash(sk);
1320 	sk->sk_bound_dev_if = 0;
1321 	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1322 		inet_reset_saddr(sk);
1323 
1324 	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1325 		sk->sk_prot->unhash(sk);
1326 		inet->inet_sport = 0;
1327 	}
1328 	sk_dst_reset(sk);
1329 	return 0;
1330 }
1331 EXPORT_SYMBOL(udp_disconnect);
1332 
1333 void udp_lib_unhash(struct sock *sk)
1334 {
1335 	if (sk_hashed(sk)) {
1336 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1337 		struct udp_hslot *hslot, *hslot2;
1338 
1339 		hslot  = udp_hashslot(udptable, sock_net(sk),
1340 				      udp_sk(sk)->udp_port_hash);
1341 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1342 
1343 		spin_lock_bh(&hslot->lock);
1344 		if (sk_nulls_del_node_init_rcu(sk)) {
1345 			hslot->count--;
1346 			inet_sk(sk)->inet_num = 0;
1347 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1348 
1349 			spin_lock(&hslot2->lock);
1350 			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1351 			hslot2->count--;
1352 			spin_unlock(&hslot2->lock);
1353 		}
1354 		spin_unlock_bh(&hslot->lock);
1355 	}
1356 }
1357 EXPORT_SYMBOL(udp_lib_unhash);
1358 
1359 /*
1360  * inet_rcv_saddr was changed, we must rehash secondary hash
1361  */
1362 void udp_lib_rehash(struct sock *sk, u16 newhash)
1363 {
1364 	if (sk_hashed(sk)) {
1365 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1366 		struct udp_hslot *hslot, *hslot2, *nhslot2;
1367 
1368 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1369 		nhslot2 = udp_hashslot2(udptable, newhash);
1370 		udp_sk(sk)->udp_portaddr_hash = newhash;
1371 		if (hslot2 != nhslot2) {
1372 			hslot = udp_hashslot(udptable, sock_net(sk),
1373 					     udp_sk(sk)->udp_port_hash);
1374 			/* we must lock primary chain too */
1375 			spin_lock_bh(&hslot->lock);
1376 
1377 			spin_lock(&hslot2->lock);
1378 			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1379 			hslot2->count--;
1380 			spin_unlock(&hslot2->lock);
1381 
1382 			spin_lock(&nhslot2->lock);
1383 			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1384 						 &nhslot2->head);
1385 			nhslot2->count++;
1386 			spin_unlock(&nhslot2->lock);
1387 
1388 			spin_unlock_bh(&hslot->lock);
1389 		}
1390 	}
1391 }
1392 EXPORT_SYMBOL(udp_lib_rehash);
1393 
1394 static void udp_v4_rehash(struct sock *sk)
1395 {
1396 	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1397 					  inet_sk(sk)->inet_rcv_saddr,
1398 					  inet_sk(sk)->inet_num);
1399 	udp_lib_rehash(sk, new_hash);
1400 }
1401 
1402 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1403 {
1404 	int rc;
1405 
1406 	if (inet_sk(sk)->inet_daddr)
1407 		sock_rps_save_rxhash(sk, skb);
1408 
1409 	rc = sock_queue_rcv_skb(sk, skb);
1410 	if (rc < 0) {
1411 		int is_udplite = IS_UDPLITE(sk);
1412 
1413 		/* Note that an ENOMEM error is charged twice */
1414 		if (rc == -ENOMEM)
1415 			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1416 					 is_udplite);
1417 		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1418 		kfree_skb(skb);
1419 		trace_udp_fail_queue_rcv_skb(rc, sk);
1420 		return -1;
1421 	}
1422 
1423 	return 0;
1424 
1425 }
1426 
1427 static struct static_key udp_encap_needed __read_mostly;
1428 void udp_encap_enable(void)
1429 {
1430 	if (!static_key_enabled(&udp_encap_needed))
1431 		static_key_slow_inc(&udp_encap_needed);
1432 }
1433 EXPORT_SYMBOL(udp_encap_enable);
1434 
1435 /* returns:
1436  *  -1: error
1437  *   0: success
1438  *  >0: "udp encap" protocol resubmission
1439  *
1440  * Note that in the success and error cases, the skb is assumed to
1441  * have either been requeued or freed.
1442  */
1443 int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1444 {
1445 	struct udp_sock *up = udp_sk(sk);
1446 	int rc;
1447 	int is_udplite = IS_UDPLITE(sk);
1448 
1449 	/*
1450 	 *	Charge it to the socket, dropping if the queue is full.
1451 	 */
1452 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1453 		goto drop;
1454 	nf_reset(skb);
1455 
1456 	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1457 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
1458 
1459 		/*
1460 		 * This is an encapsulation socket so pass the skb to
1461 		 * the socket's udp_encap_rcv() hook. Otherwise, just
1462 		 * fall through and pass this up the UDP socket.
1463 		 * up->encap_rcv() returns the following value:
1464 		 * =0 if skb was successfully passed to the encap
1465 		 *    handler or was discarded by it.
1466 		 * >0 if skb should be passed on to UDP.
1467 		 * <0 if skb should be resubmitted as proto -N
1468 		 */
1469 
1470 		/* if we're overly short, let UDP handle it */
1471 		encap_rcv = ACCESS_ONCE(up->encap_rcv);
1472 		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1473 			int ret;
1474 
1475 			ret = encap_rcv(sk, skb);
1476 			if (ret <= 0) {
1477 				UDP_INC_STATS_BH(sock_net(sk),
1478 						 UDP_MIB_INDATAGRAMS,
1479 						 is_udplite);
1480 				return -ret;
1481 			}
1482 		}
1483 
1484 		/* FALLTHROUGH -- it's a UDP Packet */
1485 	}
1486 
1487 	/*
1488 	 * 	UDP-Lite specific tests, ignored on UDP sockets
1489 	 */
1490 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
1491 
1492 		/*
1493 		 * MIB statistics other than incrementing the error count are
1494 		 * disabled for the following two types of errors: these depend
1495 		 * on the application settings, not on the functioning of the
1496 		 * protocol stack as such.
1497 		 *
1498 		 * RFC 3828 here recommends (sec 3.3): "There should also be a
1499 		 * way ... to ... at least let the receiving application block
1500 		 * delivery of packets with coverage values less than a value
1501 		 * provided by the application."
1502 		 */
1503 		if (up->pcrlen == 0) {          /* full coverage was set  */
1504 			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: partial coverage %d while full coverage %d requested\n",
1505 				       UDP_SKB_CB(skb)->cscov, skb->len);
1506 			goto drop;
1507 		}
1508 		/* The next case involves violating the min. coverage requested
1509 		 * by the receiver. This is subtle: if receiver wants x and x is
1510 		 * greater than the buffersize/MTU then receiver will complain
1511 		 * that it wants x while sender emits packets of smaller size y.
1512 		 * Therefore the above ...()->partial_cov statement is essential.
1513 		 */
1514 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1515 			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: coverage %d too small, need min %d\n",
1516 				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
1517 			goto drop;
1518 		}
1519 	}
1520 
1521 	if (rcu_access_pointer(sk->sk_filter) &&
1522 	    udp_lib_checksum_complete(skb))
1523 		goto csum_error;
1524 
1525 
1526 	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
1527 		goto drop;
1528 
1529 	rc = 0;
1530 
1531 	ipv4_pktinfo_prepare(skb);
1532 	bh_lock_sock(sk);
1533 	if (!sock_owned_by_user(sk))
1534 		rc = __udp_queue_rcv_skb(sk, skb);
1535 	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
1536 		bh_unlock_sock(sk);
1537 		goto drop;
1538 	}
1539 	bh_unlock_sock(sk);
1540 
1541 	return rc;
1542 
1543 csum_error:
1544 	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1545 drop:
1546 	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1547 	atomic_inc(&sk->sk_drops);
1548 	kfree_skb(skb);
1549 	return -1;
1550 }
1551 
1552 
1553 static void flush_stack(struct sock **stack, unsigned int count,
1554 			struct sk_buff *skb, unsigned int final)
1555 {
1556 	unsigned int i;
1557 	struct sk_buff *skb1 = NULL;
1558 	struct sock *sk;
1559 
1560 	for (i = 0; i < count; i++) {
1561 		sk = stack[i];
1562 		if (likely(skb1 == NULL))
1563 			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
1564 
1565 		if (!skb1) {
1566 			atomic_inc(&sk->sk_drops);
1567 			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1568 					 IS_UDPLITE(sk));
1569 			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1570 					 IS_UDPLITE(sk));
1571 		}
1572 
1573 		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1574 			skb1 = NULL;
1575 	}
1576 	if (unlikely(skb1))
1577 		kfree_skb(skb1);
1578 }
1579 
1580 /*
1581  *	Multicasts and broadcasts go to each listener.
1582  *
1583  *	Note: called only from the BH handler context.
1584  */
1585 static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1586 				    struct udphdr  *uh,
1587 				    __be32 saddr, __be32 daddr,
1588 				    struct udp_table *udptable)
1589 {
1590 	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1591 	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1592 	int dif;
1593 	unsigned int i, count = 0;
1594 
1595 	spin_lock(&hslot->lock);
1596 	sk = sk_nulls_head(&hslot->head);
1597 	dif = skb->dev->ifindex;
1598 	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1599 	while (sk) {
1600 		stack[count++] = sk;
1601 		sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1602 				       daddr, uh->source, saddr, dif);
1603 		if (unlikely(count == ARRAY_SIZE(stack))) {
1604 			if (!sk)
1605 				break;
1606 			flush_stack(stack, count, skb, ~0);
1607 			count = 0;
1608 		}
1609 	}
1610 	/*
1611 	 * before releasing chain lock, we must take a reference on sockets
1612 	 */
1613 	for (i = 0; i < count; i++)
1614 		sock_hold(stack[i]);
1615 
1616 	spin_unlock(&hslot->lock);
1617 
1618 	/*
1619 	 * do the slow work with no lock held
1620 	 */
1621 	if (count) {
1622 		flush_stack(stack, count, skb, count - 1);
1623 
1624 		for (i = 0; i < count; i++)
1625 			sock_put(stack[i]);
1626 	} else {
1627 		kfree_skb(skb);
1628 	}
1629 	return 0;
1630 }
1631 
1632 /* Initialize UDP checksum. If exited with zero value (success),
1633  * CHECKSUM_UNNECESSARY means, that no more checks are required.
1634  * Otherwise, csum completion requires chacksumming packet body,
1635  * including udp header and folding it to skb->csum.
1636  */
1637 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
1638 				 int proto)
1639 {
1640 	const struct iphdr *iph;
1641 	int err;
1642 
1643 	UDP_SKB_CB(skb)->partial_cov = 0;
1644 	UDP_SKB_CB(skb)->cscov = skb->len;
1645 
1646 	if (proto == IPPROTO_UDPLITE) {
1647 		err = udplite_checksum_init(skb, uh);
1648 		if (err)
1649 			return err;
1650 	}
1651 
1652 	iph = ip_hdr(skb);
1653 	if (uh->check == 0) {
1654 		skb->ip_summed = CHECKSUM_UNNECESSARY;
1655 	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
1656 		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1657 				      proto, skb->csum))
1658 			skb->ip_summed = CHECKSUM_UNNECESSARY;
1659 	}
1660 	if (!skb_csum_unnecessary(skb))
1661 		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1662 					       skb->len, proto, 0);
1663 	/* Probably, we should checksum udp header (it should be in cache
1664 	 * in any case) and data in tiny packets (< rx copybreak).
1665 	 */
1666 
1667 	return 0;
1668 }
1669 
1670 /*
1671  *	All we need to do is get the socket, and then do a checksum.
1672  */
1673 
1674 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1675 		   int proto)
1676 {
1677 	struct sock *sk;
1678 	struct udphdr *uh;
1679 	unsigned short ulen;
1680 	struct rtable *rt = skb_rtable(skb);
1681 	__be32 saddr, daddr;
1682 	struct net *net = dev_net(skb->dev);
1683 
1684 	/*
1685 	 *  Validate the packet.
1686 	 */
1687 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1688 		goto drop;		/* No space for header. */
1689 
1690 	uh   = udp_hdr(skb);
1691 	ulen = ntohs(uh->len);
1692 	saddr = ip_hdr(skb)->saddr;
1693 	daddr = ip_hdr(skb)->daddr;
1694 
1695 	if (ulen > skb->len)
1696 		goto short_packet;
1697 
1698 	if (proto == IPPROTO_UDP) {
1699 		/* UDP validates ulen. */
1700 		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
1701 			goto short_packet;
1702 		uh = udp_hdr(skb);
1703 	}
1704 
1705 	if (udp4_csum_init(skb, uh, proto))
1706 		goto csum_error;
1707 
1708 	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1709 		return __udp4_lib_mcast_deliver(net, skb, uh,
1710 				saddr, daddr, udptable);
1711 
1712 	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1713 
1714 	if (sk != NULL) {
1715 		int ret;
1716 
1717 		sk_mark_napi_id(sk, skb);
1718 		ret = udp_queue_rcv_skb(sk, skb);
1719 		sock_put(sk);
1720 
1721 		/* a return value > 0 means to resubmit the input, but
1722 		 * it wants the return to be -protocol, or 0
1723 		 */
1724 		if (ret > 0)
1725 			return -ret;
1726 		return 0;
1727 	}
1728 
1729 	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1730 		goto drop;
1731 	nf_reset(skb);
1732 
1733 	/* No socket. Drop packet silently, if checksum is wrong */
1734 	if (udp_lib_checksum_complete(skb))
1735 		goto csum_error;
1736 
1737 	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1738 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
1739 
1740 	/*
1741 	 * Hmm.  We got an UDP packet to a port to which we
1742 	 * don't wanna listen.  Ignore it.
1743 	 */
1744 	kfree_skb(skb);
1745 	return 0;
1746 
1747 short_packet:
1748 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1749 		       proto == IPPROTO_UDPLITE ? "Lite" : "",
1750 		       &saddr, ntohs(uh->source),
1751 		       ulen, skb->len,
1752 		       &daddr, ntohs(uh->dest));
1753 	goto drop;
1754 
1755 csum_error:
1756 	/*
1757 	 * RFC1122: OK.  Discards the bad packet silently (as far as
1758 	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
1759 	 */
1760 	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1761 		       proto == IPPROTO_UDPLITE ? "Lite" : "",
1762 		       &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1763 		       ulen);
1764 	UDP_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
1765 drop:
1766 	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1767 	kfree_skb(skb);
1768 	return 0;
1769 }
1770 
1771 int udp_rcv(struct sk_buff *skb)
1772 {
1773 	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1774 }
1775 
1776 void udp_destroy_sock(struct sock *sk)
1777 {
1778 	struct udp_sock *up = udp_sk(sk);
1779 	bool slow = lock_sock_fast(sk);
1780 	udp_flush_pending_frames(sk);
1781 	unlock_sock_fast(sk, slow);
1782 	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1783 		void (*encap_destroy)(struct sock *sk);
1784 		encap_destroy = ACCESS_ONCE(up->encap_destroy);
1785 		if (encap_destroy)
1786 			encap_destroy(sk);
1787 	}
1788 }
1789 
1790 /*
1791  *	Socket option code for UDP
1792  */
1793 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1794 		       char __user *optval, unsigned int optlen,
1795 		       int (*push_pending_frames)(struct sock *))
1796 {
1797 	struct udp_sock *up = udp_sk(sk);
1798 	int val;
1799 	int err = 0;
1800 	int is_udplite = IS_UDPLITE(sk);
1801 
1802 	if (optlen < sizeof(int))
1803 		return -EINVAL;
1804 
1805 	if (get_user(val, (int __user *)optval))
1806 		return -EFAULT;
1807 
1808 	switch (optname) {
1809 	case UDP_CORK:
1810 		if (val != 0) {
1811 			up->corkflag = 1;
1812 		} else {
1813 			up->corkflag = 0;
1814 			lock_sock(sk);
1815 			(*push_pending_frames)(sk);
1816 			release_sock(sk);
1817 		}
1818 		break;
1819 
1820 	case UDP_ENCAP:
1821 		switch (val) {
1822 		case 0:
1823 		case UDP_ENCAP_ESPINUDP:
1824 		case UDP_ENCAP_ESPINUDP_NON_IKE:
1825 			up->encap_rcv = xfrm4_udp_encap_rcv;
1826 			/* FALLTHROUGH */
1827 		case UDP_ENCAP_L2TPINUDP:
1828 			up->encap_type = val;
1829 			udp_encap_enable();
1830 			break;
1831 		default:
1832 			err = -ENOPROTOOPT;
1833 			break;
1834 		}
1835 		break;
1836 
1837 	/*
1838 	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
1839 	 */
1840 	/* The sender sets actual checksum coverage length via this option.
1841 	 * The case coverage > packet length is handled by send module. */
1842 	case UDPLITE_SEND_CSCOV:
1843 		if (!is_udplite)         /* Disable the option on UDP sockets */
1844 			return -ENOPROTOOPT;
1845 		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
1846 			val = 8;
1847 		else if (val > USHRT_MAX)
1848 			val = USHRT_MAX;
1849 		up->pcslen = val;
1850 		up->pcflag |= UDPLITE_SEND_CC;
1851 		break;
1852 
1853 	/* The receiver specifies a minimum checksum coverage value. To make
1854 	 * sense, this should be set to at least 8 (as done below). If zero is
1855 	 * used, this again means full checksum coverage.                     */
1856 	case UDPLITE_RECV_CSCOV:
1857 		if (!is_udplite)         /* Disable the option on UDP sockets */
1858 			return -ENOPROTOOPT;
1859 		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
1860 			val = 8;
1861 		else if (val > USHRT_MAX)
1862 			val = USHRT_MAX;
1863 		up->pcrlen = val;
1864 		up->pcflag |= UDPLITE_RECV_CC;
1865 		break;
1866 
1867 	default:
1868 		err = -ENOPROTOOPT;
1869 		break;
1870 	}
1871 
1872 	return err;
1873 }
1874 EXPORT_SYMBOL(udp_lib_setsockopt);
1875 
1876 int udp_setsockopt(struct sock *sk, int level, int optname,
1877 		   char __user *optval, unsigned int optlen)
1878 {
1879 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1880 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1881 					  udp_push_pending_frames);
1882 	return ip_setsockopt(sk, level, optname, optval, optlen);
1883 }
1884 
1885 #ifdef CONFIG_COMPAT
1886 int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1887 			  char __user *optval, unsigned int optlen)
1888 {
1889 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1890 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1891 					  udp_push_pending_frames);
1892 	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
1893 }
1894 #endif
1895 
1896 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
1897 		       char __user *optval, int __user *optlen)
1898 {
1899 	struct udp_sock *up = udp_sk(sk);
1900 	int val, len;
1901 
1902 	if (get_user(len, optlen))
1903 		return -EFAULT;
1904 
1905 	len = min_t(unsigned int, len, sizeof(int));
1906 
1907 	if (len < 0)
1908 		return -EINVAL;
1909 
1910 	switch (optname) {
1911 	case UDP_CORK:
1912 		val = up->corkflag;
1913 		break;
1914 
1915 	case UDP_ENCAP:
1916 		val = up->encap_type;
1917 		break;
1918 
1919 	/* The following two cannot be changed on UDP sockets, the return is
1920 	 * always 0 (which corresponds to the full checksum coverage of UDP). */
1921 	case UDPLITE_SEND_CSCOV:
1922 		val = up->pcslen;
1923 		break;
1924 
1925 	case UDPLITE_RECV_CSCOV:
1926 		val = up->pcrlen;
1927 		break;
1928 
1929 	default:
1930 		return -ENOPROTOOPT;
1931 	}
1932 
1933 	if (put_user(len, optlen))
1934 		return -EFAULT;
1935 	if (copy_to_user(optval, &val, len))
1936 		return -EFAULT;
1937 	return 0;
1938 }
1939 EXPORT_SYMBOL(udp_lib_getsockopt);
1940 
1941 int udp_getsockopt(struct sock *sk, int level, int optname,
1942 		   char __user *optval, int __user *optlen)
1943 {
1944 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1945 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1946 	return ip_getsockopt(sk, level, optname, optval, optlen);
1947 }
1948 
1949 #ifdef CONFIG_COMPAT
1950 int compat_udp_getsockopt(struct sock *sk, int level, int optname,
1951 				 char __user *optval, int __user *optlen)
1952 {
1953 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1954 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1955 	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
1956 }
1957 #endif
1958 /**
1959  * 	udp_poll - wait for a UDP event.
1960  *	@file - file struct
1961  *	@sock - socket
1962  *	@wait - poll table
1963  *
1964  *	This is same as datagram poll, except for the special case of
1965  *	blocking sockets. If application is using a blocking fd
1966  *	and a packet with checksum error is in the queue;
1967  *	then it could get return from select indicating data available
1968  *	but then block when reading it. Add special case code
1969  *	to work around these arguably broken applications.
1970  */
1971 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
1972 {
1973 	unsigned int mask = datagram_poll(file, sock, wait);
1974 	struct sock *sk = sock->sk;
1975 
1976 	sock_rps_record_flow(sk);
1977 
1978 	/* Check for false positives due to checksum errors */
1979 	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
1980 	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
1981 		mask &= ~(POLLIN | POLLRDNORM);
1982 
1983 	return mask;
1984 
1985 }
1986 EXPORT_SYMBOL(udp_poll);
1987 
1988 struct proto udp_prot = {
1989 	.name		   = "UDP",
1990 	.owner		   = THIS_MODULE,
1991 	.close		   = udp_lib_close,
1992 	.connect	   = ip4_datagram_connect,
1993 	.disconnect	   = udp_disconnect,
1994 	.ioctl		   = udp_ioctl,
1995 	.destroy	   = udp_destroy_sock,
1996 	.setsockopt	   = udp_setsockopt,
1997 	.getsockopt	   = udp_getsockopt,
1998 	.sendmsg	   = udp_sendmsg,
1999 	.recvmsg	   = udp_recvmsg,
2000 	.sendpage	   = udp_sendpage,
2001 	.backlog_rcv	   = __udp_queue_rcv_skb,
2002 	.release_cb	   = ip4_datagram_release_cb,
2003 	.hash		   = udp_lib_hash,
2004 	.unhash		   = udp_lib_unhash,
2005 	.rehash		   = udp_v4_rehash,
2006 	.get_port	   = udp_v4_get_port,
2007 	.memory_allocated  = &udp_memory_allocated,
2008 	.sysctl_mem	   = sysctl_udp_mem,
2009 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
2010 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
2011 	.obj_size	   = sizeof(struct udp_sock),
2012 	.slab_flags	   = SLAB_DESTROY_BY_RCU,
2013 	.h.udp_table	   = &udp_table,
2014 #ifdef CONFIG_COMPAT
2015 	.compat_setsockopt = compat_udp_setsockopt,
2016 	.compat_getsockopt = compat_udp_getsockopt,
2017 #endif
2018 	.clear_sk	   = sk_prot_clear_portaddr_nulls,
2019 };
2020 EXPORT_SYMBOL(udp_prot);
2021 
2022 /* ------------------------------------------------------------------------ */
2023 #ifdef CONFIG_PROC_FS
2024 
2025 static struct sock *udp_get_first(struct seq_file *seq, int start)
2026 {
2027 	struct sock *sk;
2028 	struct udp_iter_state *state = seq->private;
2029 	struct net *net = seq_file_net(seq);
2030 
2031 	for (state->bucket = start; state->bucket <= state->udp_table->mask;
2032 	     ++state->bucket) {
2033 		struct hlist_nulls_node *node;
2034 		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
2035 
2036 		if (hlist_nulls_empty(&hslot->head))
2037 			continue;
2038 
2039 		spin_lock_bh(&hslot->lock);
2040 		sk_nulls_for_each(sk, node, &hslot->head) {
2041 			if (!net_eq(sock_net(sk), net))
2042 				continue;
2043 			if (sk->sk_family == state->family)
2044 				goto found;
2045 		}
2046 		spin_unlock_bh(&hslot->lock);
2047 	}
2048 	sk = NULL;
2049 found:
2050 	return sk;
2051 }
2052 
2053 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
2054 {
2055 	struct udp_iter_state *state = seq->private;
2056 	struct net *net = seq_file_net(seq);
2057 
2058 	do {
2059 		sk = sk_nulls_next(sk);
2060 	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
2061 
2062 	if (!sk) {
2063 		if (state->bucket <= state->udp_table->mask)
2064 			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2065 		return udp_get_first(seq, state->bucket + 1);
2066 	}
2067 	return sk;
2068 }
2069 
2070 static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2071 {
2072 	struct sock *sk = udp_get_first(seq, 0);
2073 
2074 	if (sk)
2075 		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2076 			--pos;
2077 	return pos ? NULL : sk;
2078 }
2079 
2080 static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2081 {
2082 	struct udp_iter_state *state = seq->private;
2083 	state->bucket = MAX_UDP_PORTS;
2084 
2085 	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2086 }
2087 
2088 static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2089 {
2090 	struct sock *sk;
2091 
2092 	if (v == SEQ_START_TOKEN)
2093 		sk = udp_get_idx(seq, 0);
2094 	else
2095 		sk = udp_get_next(seq, v);
2096 
2097 	++*pos;
2098 	return sk;
2099 }
2100 
2101 static void udp_seq_stop(struct seq_file *seq, void *v)
2102 {
2103 	struct udp_iter_state *state = seq->private;
2104 
2105 	if (state->bucket <= state->udp_table->mask)
2106 		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2107 }
2108 
2109 int udp_seq_open(struct inode *inode, struct file *file)
2110 {
2111 	struct udp_seq_afinfo *afinfo = PDE_DATA(inode);
2112 	struct udp_iter_state *s;
2113 	int err;
2114 
2115 	err = seq_open_net(inode, file, &afinfo->seq_ops,
2116 			   sizeof(struct udp_iter_state));
2117 	if (err < 0)
2118 		return err;
2119 
2120 	s = ((struct seq_file *)file->private_data)->private;
2121 	s->family		= afinfo->family;
2122 	s->udp_table		= afinfo->udp_table;
2123 	return err;
2124 }
2125 EXPORT_SYMBOL(udp_seq_open);
2126 
2127 /* ------------------------------------------------------------------------ */
2128 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2129 {
2130 	struct proc_dir_entry *p;
2131 	int rc = 0;
2132 
2133 	afinfo->seq_ops.start		= udp_seq_start;
2134 	afinfo->seq_ops.next		= udp_seq_next;
2135 	afinfo->seq_ops.stop		= udp_seq_stop;
2136 
2137 	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2138 			     afinfo->seq_fops, afinfo);
2139 	if (!p)
2140 		rc = -ENOMEM;
2141 	return rc;
2142 }
2143 EXPORT_SYMBOL(udp_proc_register);
2144 
2145 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2146 {
2147 	remove_proc_entry(afinfo->name, net->proc_net);
2148 }
2149 EXPORT_SYMBOL(udp_proc_unregister);
2150 
2151 /* ------------------------------------------------------------------------ */
2152 static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2153 		int bucket, int *len)
2154 {
2155 	struct inet_sock *inet = inet_sk(sp);
2156 	__be32 dest = inet->inet_daddr;
2157 	__be32 src  = inet->inet_rcv_saddr;
2158 	__u16 destp	  = ntohs(inet->inet_dport);
2159 	__u16 srcp	  = ntohs(inet->inet_sport);
2160 
2161 	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2162 		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d%n",
2163 		bucket, src, srcp, dest, destp, sp->sk_state,
2164 		sk_wmem_alloc_get(sp),
2165 		sk_rmem_alloc_get(sp),
2166 		0, 0L, 0,
2167 		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
2168 		0, sock_i_ino(sp),
2169 		atomic_read(&sp->sk_refcnt), sp,
2170 		atomic_read(&sp->sk_drops), len);
2171 }
2172 
2173 int udp4_seq_show(struct seq_file *seq, void *v)
2174 {
2175 	if (v == SEQ_START_TOKEN)
2176 		seq_printf(seq, "%-127s\n",
2177 			   "  sl  local_address rem_address   st tx_queue "
2178 			   "rx_queue tr tm->when retrnsmt   uid  timeout "
2179 			   "inode ref pointer drops");
2180 	else {
2181 		struct udp_iter_state *state = seq->private;
2182 		int len;
2183 
2184 		udp4_format_sock(v, seq, state->bucket, &len);
2185 		seq_printf(seq, "%*s\n", 127 - len, "");
2186 	}
2187 	return 0;
2188 }
2189 
2190 static const struct file_operations udp_afinfo_seq_fops = {
2191 	.owner    = THIS_MODULE,
2192 	.open     = udp_seq_open,
2193 	.read     = seq_read,
2194 	.llseek   = seq_lseek,
2195 	.release  = seq_release_net
2196 };
2197 
2198 /* ------------------------------------------------------------------------ */
2199 static struct udp_seq_afinfo udp4_seq_afinfo = {
2200 	.name		= "udp",
2201 	.family		= AF_INET,
2202 	.udp_table	= &udp_table,
2203 	.seq_fops	= &udp_afinfo_seq_fops,
2204 	.seq_ops	= {
2205 		.show		= udp4_seq_show,
2206 	},
2207 };
2208 
2209 static int __net_init udp4_proc_init_net(struct net *net)
2210 {
2211 	return udp_proc_register(net, &udp4_seq_afinfo);
2212 }
2213 
2214 static void __net_exit udp4_proc_exit_net(struct net *net)
2215 {
2216 	udp_proc_unregister(net, &udp4_seq_afinfo);
2217 }
2218 
2219 static struct pernet_operations udp4_net_ops = {
2220 	.init = udp4_proc_init_net,
2221 	.exit = udp4_proc_exit_net,
2222 };
2223 
2224 int __init udp4_proc_init(void)
2225 {
2226 	return register_pernet_subsys(&udp4_net_ops);
2227 }
2228 
2229 void udp4_proc_exit(void)
2230 {
2231 	unregister_pernet_subsys(&udp4_net_ops);
2232 }
2233 #endif /* CONFIG_PROC_FS */
2234 
2235 static __initdata unsigned long uhash_entries;
2236 static int __init set_uhash_entries(char *str)
2237 {
2238 	ssize_t ret;
2239 
2240 	if (!str)
2241 		return 0;
2242 
2243 	ret = kstrtoul(str, 0, &uhash_entries);
2244 	if (ret)
2245 		return 0;
2246 
2247 	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2248 		uhash_entries = UDP_HTABLE_SIZE_MIN;
2249 	return 1;
2250 }
2251 __setup("uhash_entries=", set_uhash_entries);
2252 
2253 void __init udp_table_init(struct udp_table *table, const char *name)
2254 {
2255 	unsigned int i;
2256 
2257 	table->hash = alloc_large_system_hash(name,
2258 					      2 * sizeof(struct udp_hslot),
2259 					      uhash_entries,
2260 					      21, /* one slot per 2 MB */
2261 					      0,
2262 					      &table->log,
2263 					      &table->mask,
2264 					      UDP_HTABLE_SIZE_MIN,
2265 					      64 * 1024);
2266 
2267 	table->hash2 = table->hash + (table->mask + 1);
2268 	for (i = 0; i <= table->mask; i++) {
2269 		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
2270 		table->hash[i].count = 0;
2271 		spin_lock_init(&table->hash[i].lock);
2272 	}
2273 	for (i = 0; i <= table->mask; i++) {
2274 		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
2275 		table->hash2[i].count = 0;
2276 		spin_lock_init(&table->hash2[i].lock);
2277 	}
2278 }
2279 
2280 void __init udp_init(void)
2281 {
2282 	unsigned long limit;
2283 
2284 	udp_table_init(&udp_table, "UDP");
2285 	limit = nr_free_buffer_pages() / 8;
2286 	limit = max(limit, 128UL);
2287 	sysctl_udp_mem[0] = limit / 4 * 3;
2288 	sysctl_udp_mem[1] = limit;
2289 	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2290 
2291 	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2292 	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2293 }
2294 
2295 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
2296 				       netdev_features_t features)
2297 {
2298 	struct sk_buff *segs = ERR_PTR(-EINVAL);
2299 	int mac_len = skb->mac_len;
2300 	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
2301 	__be16 protocol = skb->protocol;
2302 	netdev_features_t enc_features;
2303 	int outer_hlen;
2304 
2305 	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
2306 		goto out;
2307 
2308 	skb->encapsulation = 0;
2309 	__skb_pull(skb, tnl_hlen);
2310 	skb_reset_mac_header(skb);
2311 	skb_set_network_header(skb, skb_inner_network_offset(skb));
2312 	skb->mac_len = skb_inner_network_offset(skb);
2313 	skb->protocol = htons(ETH_P_TEB);
2314 
2315 	/* segment inner packet. */
2316 	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
2317 	segs = skb_mac_gso_segment(skb, enc_features);
2318 	if (!segs || IS_ERR(segs))
2319 		goto out;
2320 
2321 	outer_hlen = skb_tnl_header_len(skb);
2322 	skb = segs;
2323 	do {
2324 		struct udphdr *uh;
2325 		int udp_offset = outer_hlen - tnl_hlen;
2326 
2327 		skb_reset_inner_headers(skb);
2328 		skb->encapsulation = 1;
2329 
2330 		skb->mac_len = mac_len;
2331 
2332 		skb_push(skb, outer_hlen);
2333 		skb_reset_mac_header(skb);
2334 		skb_set_network_header(skb, mac_len);
2335 		skb_set_transport_header(skb, udp_offset);
2336 		uh = udp_hdr(skb);
2337 		uh->len = htons(skb->len - udp_offset);
2338 
2339 		/* csum segment if tunnel sets skb with csum. */
2340 		if (protocol == htons(ETH_P_IP) && unlikely(uh->check)) {
2341 			struct iphdr *iph = ip_hdr(skb);
2342 
2343 			uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
2344 						       skb->len - udp_offset,
2345 						       IPPROTO_UDP, 0);
2346 			uh->check = csum_fold(skb_checksum(skb, udp_offset,
2347 							   skb->len - udp_offset, 0));
2348 			if (uh->check == 0)
2349 				uh->check = CSUM_MANGLED_0;
2350 
2351 		} else if (protocol == htons(ETH_P_IPV6)) {
2352 			struct ipv6hdr *ipv6h = ipv6_hdr(skb);
2353 			u32 len = skb->len - udp_offset;
2354 
2355 			uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
2356 						     len, IPPROTO_UDP, 0);
2357 			uh->check = csum_fold(skb_checksum(skb, udp_offset, len, 0));
2358 			if (uh->check == 0)
2359 				uh->check = CSUM_MANGLED_0;
2360 			skb->ip_summed = CHECKSUM_NONE;
2361 		}
2362 
2363 		skb->protocol = protocol;
2364 	} while ((skb = skb->next));
2365 out:
2366 	return segs;
2367 }
2368