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1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		The 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 <linux/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/inetdevice.h>
94 #include <linux/in.h>
95 #include <linux/errno.h>
96 #include <linux/timer.h>
97 #include <linux/mm.h>
98 #include <linux/inet.h>
99 #include <linux/netdevice.h>
100 #include <linux/slab.h>
101 #include <net/tcp_states.h>
102 #include <linux/skbuff.h>
103 #include <linux/proc_fs.h>
104 #include <linux/seq_file.h>
105 #include <net/net_namespace.h>
106 #include <net/icmp.h>
107 #include <net/inet_hashtables.h>
108 #include <net/route.h>
109 #include <net/checksum.h>
110 #include <net/xfrm.h>
111 #include <trace/events/udp.h>
112 #include <linux/static_key.h>
113 #include <trace/events/skb.h>
114 #include <net/busy_poll.h>
115 #include "udp_impl.h"
116 #include <net/sock_reuseport.h>
117 #include <net/addrconf.h>
118 
119 struct udp_table udp_table __read_mostly;
120 EXPORT_SYMBOL(udp_table);
121 
122 long sysctl_udp_mem[3] __read_mostly;
123 EXPORT_SYMBOL(sysctl_udp_mem);
124 
125 int sysctl_udp_rmem_min __read_mostly;
126 EXPORT_SYMBOL(sysctl_udp_rmem_min);
127 
128 int sysctl_udp_wmem_min __read_mostly;
129 EXPORT_SYMBOL(sysctl_udp_wmem_min);
130 
131 atomic_long_t udp_memory_allocated;
132 EXPORT_SYMBOL(udp_memory_allocated);
133 
134 #define MAX_UDP_PORTS 65536
135 #define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
136 
137 /* IPCB reference means this can not be used from early demux */
udp_lib_exact_dif_match(struct net * net,struct sk_buff * skb)138 static bool udp_lib_exact_dif_match(struct net *net, struct sk_buff *skb)
139 {
140 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
141 	if (!net->ipv4.sysctl_udp_l3mdev_accept &&
142 	    skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
143 		return true;
144 #endif
145 	return false;
146 }
147 
udp_lib_lport_inuse(struct net * net,__u16 num,const struct udp_hslot * hslot,unsigned long * bitmap,struct sock * sk,unsigned int log)148 static int udp_lib_lport_inuse(struct net *net, __u16 num,
149 			       const struct udp_hslot *hslot,
150 			       unsigned long *bitmap,
151 			       struct sock *sk, unsigned int log)
152 {
153 	struct sock *sk2;
154 	kuid_t uid = sock_i_uid(sk);
155 
156 	sk_for_each(sk2, &hslot->head) {
157 		if (net_eq(sock_net(sk2), net) &&
158 		    sk2 != sk &&
159 		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
160 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
161 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
162 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
163 		    inet_rcv_saddr_equal(sk, sk2, true)) {
164 			if (sk2->sk_reuseport && sk->sk_reuseport &&
165 			    !rcu_access_pointer(sk->sk_reuseport_cb) &&
166 			    uid_eq(uid, sock_i_uid(sk2))) {
167 				if (!bitmap)
168 					return 0;
169 			} else {
170 				if (!bitmap)
171 					return 1;
172 				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
173 					  bitmap);
174 			}
175 		}
176 	}
177 	return 0;
178 }
179 
180 /*
181  * Note: we still hold spinlock of primary hash chain, so no other writer
182  * can insert/delete a socket with local_port == num
183  */
udp_lib_lport_inuse2(struct net * net,__u16 num,struct udp_hslot * hslot2,struct sock * sk)184 static int udp_lib_lport_inuse2(struct net *net, __u16 num,
185 				struct udp_hslot *hslot2,
186 				struct sock *sk)
187 {
188 	struct sock *sk2;
189 	kuid_t uid = sock_i_uid(sk);
190 	int res = 0;
191 
192 	spin_lock(&hslot2->lock);
193 	udp_portaddr_for_each_entry(sk2, &hslot2->head) {
194 		if (net_eq(sock_net(sk2), net) &&
195 		    sk2 != sk &&
196 		    (udp_sk(sk2)->udp_port_hash == num) &&
197 		    (!sk2->sk_reuse || !sk->sk_reuse) &&
198 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
199 		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
200 		    inet_rcv_saddr_equal(sk, sk2, true)) {
201 			if (sk2->sk_reuseport && sk->sk_reuseport &&
202 			    !rcu_access_pointer(sk->sk_reuseport_cb) &&
203 			    uid_eq(uid, sock_i_uid(sk2))) {
204 				res = 0;
205 			} else {
206 				res = 1;
207 			}
208 			break;
209 		}
210 	}
211 	spin_unlock(&hslot2->lock);
212 	return res;
213 }
214 
udp_reuseport_add_sock(struct sock * sk,struct udp_hslot * hslot)215 static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot)
216 {
217 	struct net *net = sock_net(sk);
218 	kuid_t uid = sock_i_uid(sk);
219 	struct sock *sk2;
220 
221 	sk_for_each(sk2, &hslot->head) {
222 		if (net_eq(sock_net(sk2), net) &&
223 		    sk2 != sk &&
224 		    sk2->sk_family == sk->sk_family &&
225 		    ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
226 		    (udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) &&
227 		    (sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
228 		    sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
229 		    inet_rcv_saddr_equal(sk, sk2, false)) {
230 			return reuseport_add_sock(sk, sk2);
231 		}
232 	}
233 
234 	return reuseport_alloc(sk);
235 }
236 
237 /**
238  *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
239  *
240  *  @sk:          socket struct in question
241  *  @snum:        port number to look up
242  *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
243  *                   with NULL address
244  */
udp_lib_get_port(struct sock * sk,unsigned short snum,unsigned int hash2_nulladdr)245 int udp_lib_get_port(struct sock *sk, unsigned short snum,
246 		     unsigned int hash2_nulladdr)
247 {
248 	struct udp_hslot *hslot, *hslot2;
249 	struct udp_table *udptable = sk->sk_prot->h.udp_table;
250 	int    error = 1;
251 	struct net *net = sock_net(sk);
252 
253 	if (!snum) {
254 		int low, high, remaining;
255 		unsigned int rand;
256 		unsigned short first, last;
257 		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
258 
259 		inet_get_local_port_range(net, &low, &high);
260 		remaining = (high - low) + 1;
261 
262 		rand = prandom_u32();
263 		first = reciprocal_scale(rand, remaining) + low;
264 		/*
265 		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
266 		 */
267 		rand = (rand | 1) * (udptable->mask + 1);
268 		last = first + udptable->mask + 1;
269 		do {
270 			hslot = udp_hashslot(udptable, net, first);
271 			bitmap_zero(bitmap, PORTS_PER_CHAIN);
272 			spin_lock_bh(&hslot->lock);
273 			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
274 					    udptable->log);
275 
276 			snum = first;
277 			/*
278 			 * Iterate on all possible values of snum for this hash.
279 			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
280 			 * give us randomization and full range coverage.
281 			 */
282 			do {
283 				if (low <= snum && snum <= high &&
284 				    !test_bit(snum >> udptable->log, bitmap) &&
285 				    !inet_is_local_reserved_port(net, snum))
286 					goto found;
287 				snum += rand;
288 			} while (snum != first);
289 			spin_unlock_bh(&hslot->lock);
290 			cond_resched();
291 		} while (++first != last);
292 		goto fail;
293 	} else {
294 		hslot = udp_hashslot(udptable, net, snum);
295 		spin_lock_bh(&hslot->lock);
296 		if (hslot->count > 10) {
297 			int exist;
298 			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
299 
300 			slot2          &= udptable->mask;
301 			hash2_nulladdr &= udptable->mask;
302 
303 			hslot2 = udp_hashslot2(udptable, slot2);
304 			if (hslot->count < hslot2->count)
305 				goto scan_primary_hash;
306 
307 			exist = udp_lib_lport_inuse2(net, snum, hslot2, sk);
308 			if (!exist && (hash2_nulladdr != slot2)) {
309 				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
310 				exist = udp_lib_lport_inuse2(net, snum, hslot2,
311 							     sk);
312 			}
313 			if (exist)
314 				goto fail_unlock;
315 			else
316 				goto found;
317 		}
318 scan_primary_hash:
319 		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, 0))
320 			goto fail_unlock;
321 	}
322 found:
323 	inet_sk(sk)->inet_num = snum;
324 	udp_sk(sk)->udp_port_hash = snum;
325 	udp_sk(sk)->udp_portaddr_hash ^= snum;
326 	if (sk_unhashed(sk)) {
327 		if (sk->sk_reuseport &&
328 		    udp_reuseport_add_sock(sk, hslot)) {
329 			inet_sk(sk)->inet_num = 0;
330 			udp_sk(sk)->udp_port_hash = 0;
331 			udp_sk(sk)->udp_portaddr_hash ^= snum;
332 			goto fail_unlock;
333 		}
334 
335 		sk_add_node_rcu(sk, &hslot->head);
336 		hslot->count++;
337 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
338 
339 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
340 		spin_lock(&hslot2->lock);
341 		if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
342 		    sk->sk_family == AF_INET6)
343 			hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
344 					   &hslot2->head);
345 		else
346 			hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
347 					   &hslot2->head);
348 		hslot2->count++;
349 		spin_unlock(&hslot2->lock);
350 	}
351 	sock_set_flag(sk, SOCK_RCU_FREE);
352 	error = 0;
353 fail_unlock:
354 	spin_unlock_bh(&hslot->lock);
355 fail:
356 	return error;
357 }
358 EXPORT_SYMBOL(udp_lib_get_port);
359 
udp4_portaddr_hash(const struct net * net,__be32 saddr,unsigned int port)360 static u32 udp4_portaddr_hash(const struct net *net, __be32 saddr,
361 			      unsigned int port)
362 {
363 	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
364 }
365 
udp_v4_get_port(struct sock * sk,unsigned short snum)366 int udp_v4_get_port(struct sock *sk, unsigned short snum)
367 {
368 	unsigned int hash2_nulladdr =
369 		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
370 	unsigned int hash2_partial =
371 		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
372 
373 	/* precompute partial secondary hash */
374 	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
375 	return udp_lib_get_port(sk, snum, hash2_nulladdr);
376 }
377 
compute_score(struct sock * sk,struct net * net,__be32 saddr,__be16 sport,__be32 daddr,unsigned short hnum,int dif,int sdif,bool exact_dif)378 static int compute_score(struct sock *sk, struct net *net,
379 			 __be32 saddr, __be16 sport,
380 			 __be32 daddr, unsigned short hnum,
381 			 int dif, int sdif, bool exact_dif)
382 {
383 	int score;
384 	struct inet_sock *inet;
385 
386 	if (!net_eq(sock_net(sk), net) ||
387 	    udp_sk(sk)->udp_port_hash != hnum ||
388 	    ipv6_only_sock(sk))
389 		return -1;
390 
391 	score = (sk->sk_family == PF_INET) ? 2 : 1;
392 	inet = inet_sk(sk);
393 
394 	if (inet->inet_rcv_saddr) {
395 		if (inet->inet_rcv_saddr != daddr)
396 			return -1;
397 		score += 4;
398 	}
399 
400 	if (inet->inet_daddr) {
401 		if (inet->inet_daddr != saddr)
402 			return -1;
403 		score += 4;
404 	}
405 
406 	if (inet->inet_dport) {
407 		if (inet->inet_dport != sport)
408 			return -1;
409 		score += 4;
410 	}
411 
412 	if (sk->sk_bound_dev_if || exact_dif) {
413 		bool dev_match = (sk->sk_bound_dev_if == dif ||
414 				  sk->sk_bound_dev_if == sdif);
415 
416 		if (!dev_match)
417 			return -1;
418 		if (sk->sk_bound_dev_if)
419 			score += 4;
420 	}
421 
422 	if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
423 		score++;
424 	return score;
425 }
426 
udp_ehashfn(const struct net * net,const __be32 laddr,const __u16 lport,const __be32 faddr,const __be16 fport)427 static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
428 		       const __u16 lport, const __be32 faddr,
429 		       const __be16 fport)
430 {
431 	static u32 udp_ehash_secret __read_mostly;
432 
433 	net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
434 
435 	return __inet_ehashfn(laddr, lport, faddr, fport,
436 			      udp_ehash_secret + net_hash_mix(net));
437 }
438 
439 /* called with rcu_read_lock() */
udp4_lib_lookup2(struct net * net,__be32 saddr,__be16 sport,__be32 daddr,unsigned int hnum,int dif,int sdif,bool exact_dif,struct udp_hslot * hslot2,struct sk_buff * skb)440 static struct sock *udp4_lib_lookup2(struct net *net,
441 				     __be32 saddr, __be16 sport,
442 				     __be32 daddr, unsigned int hnum,
443 				     int dif, int sdif, bool exact_dif,
444 				     struct udp_hslot *hslot2,
445 				     struct sk_buff *skb)
446 {
447 	struct sock *sk, *result;
448 	int score, badness, matches = 0, reuseport = 0;
449 	u32 hash = 0;
450 
451 	result = NULL;
452 	badness = 0;
453 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
454 		score = compute_score(sk, net, saddr, sport,
455 				      daddr, hnum, dif, sdif, exact_dif);
456 		if (score > badness) {
457 			reuseport = sk->sk_reuseport;
458 			if (reuseport) {
459 				hash = udp_ehashfn(net, daddr, hnum,
460 						   saddr, sport);
461 				result = reuseport_select_sock(sk, hash, skb,
462 							sizeof(struct udphdr));
463 				if (result)
464 					return result;
465 				matches = 1;
466 			}
467 			badness = score;
468 			result = sk;
469 		} else if (score == badness && reuseport) {
470 			matches++;
471 			if (reciprocal_scale(hash, matches) == 0)
472 				result = sk;
473 			hash = next_pseudo_random32(hash);
474 		}
475 	}
476 	return result;
477 }
478 
479 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
480  * harder than this. -DaveM
481  */
__udp4_lib_lookup(struct net * net,__be32 saddr,__be16 sport,__be32 daddr,__be16 dport,int dif,int sdif,struct udp_table * udptable,struct sk_buff * skb)482 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
483 		__be16 sport, __be32 daddr, __be16 dport, int dif,
484 		int sdif, struct udp_table *udptable, struct sk_buff *skb)
485 {
486 	struct sock *sk, *result;
487 	unsigned short hnum = ntohs(dport);
488 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
489 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
490 	bool exact_dif = udp_lib_exact_dif_match(net, skb);
491 	int score, badness, matches = 0, reuseport = 0;
492 	u32 hash = 0;
493 
494 	if (hslot->count > 10) {
495 		hash2 = udp4_portaddr_hash(net, daddr, hnum);
496 		slot2 = hash2 & udptable->mask;
497 		hslot2 = &udptable->hash2[slot2];
498 		if (hslot->count < hslot2->count)
499 			goto begin;
500 
501 		result = udp4_lib_lookup2(net, saddr, sport,
502 					  daddr, hnum, dif, sdif,
503 					  exact_dif, hslot2, skb);
504 		if (!result) {
505 			unsigned int old_slot2 = slot2;
506 			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
507 			slot2 = hash2 & udptable->mask;
508 			/* avoid searching the same slot again. */
509 			if (unlikely(slot2 == old_slot2))
510 				return result;
511 
512 			hslot2 = &udptable->hash2[slot2];
513 			if (hslot->count < hslot2->count)
514 				goto begin;
515 
516 			result = udp4_lib_lookup2(net, saddr, sport,
517 						  daddr, hnum, dif, sdif,
518 						  exact_dif, hslot2, skb);
519 		}
520 		return result;
521 	}
522 begin:
523 	result = NULL;
524 	badness = 0;
525 	sk_for_each_rcu(sk, &hslot->head) {
526 		score = compute_score(sk, net, saddr, sport,
527 				      daddr, hnum, dif, sdif, exact_dif);
528 		if (score > badness) {
529 			reuseport = sk->sk_reuseport;
530 			if (reuseport) {
531 				hash = udp_ehashfn(net, daddr, hnum,
532 						   saddr, sport);
533 				result = reuseport_select_sock(sk, hash, skb,
534 							sizeof(struct udphdr));
535 				if (result)
536 					return result;
537 				matches = 1;
538 			}
539 			result = sk;
540 			badness = score;
541 		} else if (score == badness && reuseport) {
542 			matches++;
543 			if (reciprocal_scale(hash, matches) == 0)
544 				result = sk;
545 			hash = next_pseudo_random32(hash);
546 		}
547 	}
548 	return result;
549 }
550 EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
551 
__udp4_lib_lookup_skb(struct sk_buff * skb,__be16 sport,__be16 dport,struct udp_table * udptable)552 static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
553 						 __be16 sport, __be16 dport,
554 						 struct udp_table *udptable)
555 {
556 	const struct iphdr *iph = ip_hdr(skb);
557 
558 	return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
559 				 iph->daddr, dport, inet_iif(skb),
560 				 inet_sdif(skb), udptable, skb);
561 }
562 
udp4_lib_lookup_skb(struct sk_buff * skb,__be16 sport,__be16 dport)563 struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
564 				 __be16 sport, __be16 dport)
565 {
566 	const struct iphdr *iph = ip_hdr(skb);
567 
568 	return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
569 				 iph->daddr, dport, inet_iif(skb),
570 				 inet_sdif(skb), &udp_table, NULL);
571 }
572 EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb);
573 
574 /* Must be called under rcu_read_lock().
575  * Does increment socket refcount.
576  */
577 #if IS_ENABLED(CONFIG_NETFILTER_XT_MATCH_SOCKET) || \
578     IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TPROXY) || \
579     IS_ENABLED(CONFIG_NF_SOCKET_IPV4)
udp4_lib_lookup(struct net * net,__be32 saddr,__be16 sport,__be32 daddr,__be16 dport,int dif)580 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
581 			     __be32 daddr, __be16 dport, int dif)
582 {
583 	struct sock *sk;
584 
585 	sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
586 			       dif, 0, &udp_table, NULL);
587 	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
588 		sk = NULL;
589 	return sk;
590 }
591 EXPORT_SYMBOL_GPL(udp4_lib_lookup);
592 #endif
593 
__udp_is_mcast_sock(struct net * net,struct sock * sk,__be16 loc_port,__be32 loc_addr,__be16 rmt_port,__be32 rmt_addr,int dif,int sdif,unsigned short hnum)594 static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
595 				       __be16 loc_port, __be32 loc_addr,
596 				       __be16 rmt_port, __be32 rmt_addr,
597 				       int dif, int sdif, unsigned short hnum)
598 {
599 	struct inet_sock *inet = inet_sk(sk);
600 
601 	if (!net_eq(sock_net(sk), net) ||
602 	    udp_sk(sk)->udp_port_hash != hnum ||
603 	    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
604 	    (inet->inet_dport != rmt_port && inet->inet_dport) ||
605 	    (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
606 	    ipv6_only_sock(sk) ||
607 	    (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
608 	     sk->sk_bound_dev_if != sdif))
609 		return false;
610 	if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif))
611 		return false;
612 	return true;
613 }
614 
615 /*
616  * This routine is called by the ICMP module when it gets some
617  * sort of error condition.  If err < 0 then the socket should
618  * be closed and the error returned to the user.  If err > 0
619  * it's just the icmp type << 8 | icmp code.
620  * Header points to the ip header of the error packet. We move
621  * on past this. Then (as it used to claim before adjustment)
622  * header points to the first 8 bytes of the udp header.  We need
623  * to find the appropriate port.
624  */
625 
__udp4_lib_err(struct sk_buff * skb,u32 info,struct udp_table * udptable)626 void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
627 {
628 	struct inet_sock *inet;
629 	const struct iphdr *iph = (const struct iphdr *)skb->data;
630 	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
631 	const int type = icmp_hdr(skb)->type;
632 	const int code = icmp_hdr(skb)->code;
633 	struct sock *sk;
634 	int harderr;
635 	int err;
636 	struct net *net = dev_net(skb->dev);
637 
638 	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
639 			       iph->saddr, uh->source, skb->dev->ifindex, 0,
640 			       udptable, NULL);
641 	if (!sk) {
642 		__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
643 		return;	/* No socket for error */
644 	}
645 
646 	err = 0;
647 	harderr = 0;
648 	inet = inet_sk(sk);
649 
650 	switch (type) {
651 	default:
652 	case ICMP_TIME_EXCEEDED:
653 		err = EHOSTUNREACH;
654 		break;
655 	case ICMP_SOURCE_QUENCH:
656 		goto out;
657 	case ICMP_PARAMETERPROB:
658 		err = EPROTO;
659 		harderr = 1;
660 		break;
661 	case ICMP_DEST_UNREACH:
662 		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
663 			ipv4_sk_update_pmtu(skb, sk, info);
664 			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
665 				err = EMSGSIZE;
666 				harderr = 1;
667 				break;
668 			}
669 			goto out;
670 		}
671 		err = EHOSTUNREACH;
672 		if (code <= NR_ICMP_UNREACH) {
673 			harderr = icmp_err_convert[code].fatal;
674 			err = icmp_err_convert[code].errno;
675 		}
676 		break;
677 	case ICMP_REDIRECT:
678 		ipv4_sk_redirect(skb, sk);
679 		goto out;
680 	}
681 
682 	/*
683 	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
684 	 *	4.1.3.3.
685 	 */
686 	if (!inet->recverr) {
687 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
688 			goto out;
689 	} else
690 		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
691 
692 	sk->sk_err = err;
693 	sk->sk_error_report(sk);
694 out:
695 	return;
696 }
697 
udp_err(struct sk_buff * skb,u32 info)698 void udp_err(struct sk_buff *skb, u32 info)
699 {
700 	__udp4_lib_err(skb, info, &udp_table);
701 }
702 
703 /*
704  * Throw away all pending data and cancel the corking. Socket is locked.
705  */
udp_flush_pending_frames(struct sock * sk)706 void udp_flush_pending_frames(struct sock *sk)
707 {
708 	struct udp_sock *up = udp_sk(sk);
709 
710 	if (up->pending) {
711 		up->len = 0;
712 		up->pending = 0;
713 		ip_flush_pending_frames(sk);
714 	}
715 }
716 EXPORT_SYMBOL(udp_flush_pending_frames);
717 
718 /**
719  * 	udp4_hwcsum  -  handle outgoing HW checksumming
720  * 	@skb: 	sk_buff containing the filled-in UDP header
721  * 	        (checksum field must be zeroed out)
722  *	@src:	source IP address
723  *	@dst:	destination IP address
724  */
udp4_hwcsum(struct sk_buff * skb,__be32 src,__be32 dst)725 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
726 {
727 	struct udphdr *uh = udp_hdr(skb);
728 	int offset = skb_transport_offset(skb);
729 	int len = skb->len - offset;
730 	int hlen = len;
731 	__wsum csum = 0;
732 
733 	if (!skb_has_frag_list(skb)) {
734 		/*
735 		 * Only one fragment on the socket.
736 		 */
737 		skb->csum_start = skb_transport_header(skb) - skb->head;
738 		skb->csum_offset = offsetof(struct udphdr, check);
739 		uh->check = ~csum_tcpudp_magic(src, dst, len,
740 					       IPPROTO_UDP, 0);
741 	} else {
742 		struct sk_buff *frags;
743 
744 		/*
745 		 * HW-checksum won't work as there are two or more
746 		 * fragments on the socket so that all csums of sk_buffs
747 		 * should be together
748 		 */
749 		skb_walk_frags(skb, frags) {
750 			csum = csum_add(csum, frags->csum);
751 			hlen -= frags->len;
752 		}
753 
754 		csum = skb_checksum(skb, offset, hlen, csum);
755 		skb->ip_summed = CHECKSUM_NONE;
756 
757 		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
758 		if (uh->check == 0)
759 			uh->check = CSUM_MANGLED_0;
760 	}
761 }
762 EXPORT_SYMBOL_GPL(udp4_hwcsum);
763 
764 /* Function to set UDP checksum for an IPv4 UDP packet. This is intended
765  * for the simple case like when setting the checksum for a UDP tunnel.
766  */
udp_set_csum(bool nocheck,struct sk_buff * skb,__be32 saddr,__be32 daddr,int len)767 void udp_set_csum(bool nocheck, struct sk_buff *skb,
768 		  __be32 saddr, __be32 daddr, int len)
769 {
770 	struct udphdr *uh = udp_hdr(skb);
771 
772 	if (nocheck) {
773 		uh->check = 0;
774 	} else if (skb_is_gso(skb)) {
775 		uh->check = ~udp_v4_check(len, saddr, daddr, 0);
776 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
777 		uh->check = 0;
778 		uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb));
779 		if (uh->check == 0)
780 			uh->check = CSUM_MANGLED_0;
781 	} else {
782 		skb->ip_summed = CHECKSUM_PARTIAL;
783 		skb->csum_start = skb_transport_header(skb) - skb->head;
784 		skb->csum_offset = offsetof(struct udphdr, check);
785 		uh->check = ~udp_v4_check(len, saddr, daddr, 0);
786 	}
787 }
788 EXPORT_SYMBOL(udp_set_csum);
789 
udp_send_skb(struct sk_buff * skb,struct flowi4 * fl4)790 static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
791 {
792 	struct sock *sk = skb->sk;
793 	struct inet_sock *inet = inet_sk(sk);
794 	struct udphdr *uh;
795 	int err = 0;
796 	int is_udplite = IS_UDPLITE(sk);
797 	int offset = skb_transport_offset(skb);
798 	int len = skb->len - offset;
799 	__wsum csum = 0;
800 
801 	/*
802 	 * Create a UDP header
803 	 */
804 	uh = udp_hdr(skb);
805 	uh->source = inet->inet_sport;
806 	uh->dest = fl4->fl4_dport;
807 	uh->len = htons(len);
808 	uh->check = 0;
809 
810 	if (is_udplite)  				 /*     UDP-Lite      */
811 		csum = udplite_csum(skb);
812 
813 	else if (sk->sk_no_check_tx) {			 /* UDP csum off */
814 
815 		skb->ip_summed = CHECKSUM_NONE;
816 		goto send;
817 
818 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
819 
820 		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
821 		goto send;
822 
823 	} else
824 		csum = udp_csum(skb);
825 
826 	/* add protocol-dependent pseudo-header */
827 	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
828 				      sk->sk_protocol, csum);
829 	if (uh->check == 0)
830 		uh->check = CSUM_MANGLED_0;
831 
832 send:
833 	err = ip_send_skb(sock_net(sk), skb);
834 	if (err) {
835 		if (err == -ENOBUFS && !inet->recverr) {
836 			UDP_INC_STATS(sock_net(sk),
837 				      UDP_MIB_SNDBUFERRORS, is_udplite);
838 			err = 0;
839 		}
840 	} else
841 		UDP_INC_STATS(sock_net(sk),
842 			      UDP_MIB_OUTDATAGRAMS, is_udplite);
843 	return err;
844 }
845 
846 /*
847  * Push out all pending data as one UDP datagram. Socket is locked.
848  */
udp_push_pending_frames(struct sock * sk)849 int udp_push_pending_frames(struct sock *sk)
850 {
851 	struct udp_sock  *up = udp_sk(sk);
852 	struct inet_sock *inet = inet_sk(sk);
853 	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
854 	struct sk_buff *skb;
855 	int err = 0;
856 
857 	skb = ip_finish_skb(sk, fl4);
858 	if (!skb)
859 		goto out;
860 
861 	err = udp_send_skb(skb, fl4);
862 
863 out:
864 	up->len = 0;
865 	up->pending = 0;
866 	return err;
867 }
868 EXPORT_SYMBOL(udp_push_pending_frames);
869 
udp_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)870 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
871 {
872 	struct inet_sock *inet = inet_sk(sk);
873 	struct udp_sock *up = udp_sk(sk);
874 	struct flowi4 fl4_stack;
875 	struct flowi4 *fl4;
876 	int ulen = len;
877 	struct ipcm_cookie ipc;
878 	struct rtable *rt = NULL;
879 	int free = 0;
880 	int connected = 0;
881 	__be32 daddr, faddr, saddr;
882 	__be16 dport;
883 	u8  tos;
884 	int err, is_udplite = IS_UDPLITE(sk);
885 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
886 	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
887 	struct sk_buff *skb;
888 	struct ip_options_data opt_copy;
889 
890 	if (len > 0xFFFF)
891 		return -EMSGSIZE;
892 
893 	/*
894 	 *	Check the flags.
895 	 */
896 
897 	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
898 		return -EOPNOTSUPP;
899 
900 	ipc.opt = NULL;
901 	ipc.tx_flags = 0;
902 	ipc.ttl = 0;
903 	ipc.tos = -1;
904 
905 	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
906 
907 	fl4 = &inet->cork.fl.u.ip4;
908 	if (up->pending) {
909 		/*
910 		 * There are pending frames.
911 		 * The socket lock must be held while it's corked.
912 		 */
913 		lock_sock(sk);
914 		if (likely(up->pending)) {
915 			if (unlikely(up->pending != AF_INET)) {
916 				release_sock(sk);
917 				return -EINVAL;
918 			}
919 			goto do_append_data;
920 		}
921 		release_sock(sk);
922 	}
923 	ulen += sizeof(struct udphdr);
924 
925 	/*
926 	 *	Get and verify the address.
927 	 */
928 	if (msg->msg_name) {
929 		DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
930 		if (msg->msg_namelen < sizeof(*usin))
931 			return -EINVAL;
932 		if (usin->sin_family != AF_INET) {
933 			if (usin->sin_family != AF_UNSPEC)
934 				return -EAFNOSUPPORT;
935 		}
936 
937 		daddr = usin->sin_addr.s_addr;
938 		dport = usin->sin_port;
939 		if (dport == 0)
940 			return -EINVAL;
941 	} else {
942 		if (sk->sk_state != TCP_ESTABLISHED)
943 			return -EDESTADDRREQ;
944 		daddr = inet->inet_daddr;
945 		dport = inet->inet_dport;
946 		/* Open fast path for connected socket.
947 		   Route will not be used, if at least one option is set.
948 		 */
949 		connected = 1;
950 	}
951 
952 	ipc.sockc.tsflags = sk->sk_tsflags;
953 	ipc.addr = inet->inet_saddr;
954 	ipc.oif = sk->sk_bound_dev_if;
955 
956 	if (msg->msg_controllen) {
957 		err = ip_cmsg_send(sk, msg, &ipc, sk->sk_family == AF_INET6);
958 		if (unlikely(err)) {
959 			kfree(ipc.opt);
960 			return err;
961 		}
962 		if (ipc.opt)
963 			free = 1;
964 		connected = 0;
965 	}
966 	if (!ipc.opt) {
967 		struct ip_options_rcu *inet_opt;
968 
969 		rcu_read_lock();
970 		inet_opt = rcu_dereference(inet->inet_opt);
971 		if (inet_opt) {
972 			memcpy(&opt_copy, inet_opt,
973 			       sizeof(*inet_opt) + inet_opt->opt.optlen);
974 			ipc.opt = &opt_copy.opt;
975 		}
976 		rcu_read_unlock();
977 	}
978 
979 	saddr = ipc.addr;
980 	ipc.addr = faddr = daddr;
981 
982 	sock_tx_timestamp(sk, ipc.sockc.tsflags, &ipc.tx_flags);
983 
984 	if (ipc.opt && ipc.opt->opt.srr) {
985 		if (!daddr) {
986 			err = -EINVAL;
987 			goto out_free;
988 		}
989 		faddr = ipc.opt->opt.faddr;
990 		connected = 0;
991 	}
992 	tos = get_rttos(&ipc, inet);
993 	if (sock_flag(sk, SOCK_LOCALROUTE) ||
994 	    (msg->msg_flags & MSG_DONTROUTE) ||
995 	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
996 		tos |= RTO_ONLINK;
997 		connected = 0;
998 	}
999 
1000 	if (ipv4_is_multicast(daddr)) {
1001 		if (!ipc.oif)
1002 			ipc.oif = inet->mc_index;
1003 		if (!saddr)
1004 			saddr = inet->mc_addr;
1005 		connected = 0;
1006 	} else if (!ipc.oif)
1007 		ipc.oif = inet->uc_index;
1008 
1009 	if (connected)
1010 		rt = (struct rtable *)sk_dst_check(sk, 0);
1011 
1012 	if (!rt) {
1013 		struct net *net = sock_net(sk);
1014 		__u8 flow_flags = inet_sk_flowi_flags(sk);
1015 
1016 		fl4 = &fl4_stack;
1017 
1018 		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
1019 				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
1020 				   flow_flags,
1021 				   faddr, saddr, dport, inet->inet_sport,
1022 				   sk->sk_uid);
1023 
1024 		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
1025 		rt = ip_route_output_flow(net, fl4, sk);
1026 		if (IS_ERR(rt)) {
1027 			err = PTR_ERR(rt);
1028 			rt = NULL;
1029 			if (err == -ENETUNREACH)
1030 				IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1031 			goto out;
1032 		}
1033 
1034 		err = -EACCES;
1035 		if ((rt->rt_flags & RTCF_BROADCAST) &&
1036 		    !sock_flag(sk, SOCK_BROADCAST))
1037 			goto out;
1038 		if (connected)
1039 			sk_dst_set(sk, dst_clone(&rt->dst));
1040 	}
1041 
1042 	if (msg->msg_flags&MSG_CONFIRM)
1043 		goto do_confirm;
1044 back_from_confirm:
1045 
1046 	saddr = fl4->saddr;
1047 	if (!ipc.addr)
1048 		daddr = ipc.addr = fl4->daddr;
1049 
1050 	/* Lockless fast path for the non-corking case. */
1051 	if (!corkreq) {
1052 		skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
1053 				  sizeof(struct udphdr), &ipc, &rt,
1054 				  msg->msg_flags);
1055 		err = PTR_ERR(skb);
1056 		if (!IS_ERR_OR_NULL(skb))
1057 			err = udp_send_skb(skb, fl4);
1058 		goto out;
1059 	}
1060 
1061 	lock_sock(sk);
1062 	if (unlikely(up->pending)) {
1063 		/* The socket is already corked while preparing it. */
1064 		/* ... which is an evident application bug. --ANK */
1065 		release_sock(sk);
1066 
1067 		net_dbg_ratelimited("socket already corked\n");
1068 		err = -EINVAL;
1069 		goto out;
1070 	}
1071 	/*
1072 	 *	Now cork the socket to pend data.
1073 	 */
1074 	fl4 = &inet->cork.fl.u.ip4;
1075 	fl4->daddr = daddr;
1076 	fl4->saddr = saddr;
1077 	fl4->fl4_dport = dport;
1078 	fl4->fl4_sport = inet->inet_sport;
1079 	up->pending = AF_INET;
1080 
1081 do_append_data:
1082 	up->len += ulen;
1083 	err = ip_append_data(sk, fl4, getfrag, msg, ulen,
1084 			     sizeof(struct udphdr), &ipc, &rt,
1085 			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1086 	if (err)
1087 		udp_flush_pending_frames(sk);
1088 	else if (!corkreq)
1089 		err = udp_push_pending_frames(sk);
1090 	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1091 		up->pending = 0;
1092 	release_sock(sk);
1093 
1094 out:
1095 	ip_rt_put(rt);
1096 out_free:
1097 	if (free)
1098 		kfree(ipc.opt);
1099 	if (!err)
1100 		return len;
1101 	/*
1102 	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1103 	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1104 	 * we don't have a good statistic (IpOutDiscards but it can be too many
1105 	 * things).  We could add another new stat but at least for now that
1106 	 * seems like overkill.
1107 	 */
1108 	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1109 		UDP_INC_STATS(sock_net(sk),
1110 			      UDP_MIB_SNDBUFERRORS, is_udplite);
1111 	}
1112 	return err;
1113 
1114 do_confirm:
1115 	if (msg->msg_flags & MSG_PROBE)
1116 		dst_confirm_neigh(&rt->dst, &fl4->daddr);
1117 	if (!(msg->msg_flags&MSG_PROBE) || len)
1118 		goto back_from_confirm;
1119 	err = 0;
1120 	goto out;
1121 }
1122 EXPORT_SYMBOL(udp_sendmsg);
1123 
udp_sendpage(struct sock * sk,struct page * page,int offset,size_t size,int flags)1124 int udp_sendpage(struct sock *sk, struct page *page, int offset,
1125 		 size_t size, int flags)
1126 {
1127 	struct inet_sock *inet = inet_sk(sk);
1128 	struct udp_sock *up = udp_sk(sk);
1129 	int ret;
1130 
1131 	if (flags & MSG_SENDPAGE_NOTLAST)
1132 		flags |= MSG_MORE;
1133 
1134 	if (!up->pending) {
1135 		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
1136 
1137 		/* Call udp_sendmsg to specify destination address which
1138 		 * sendpage interface can't pass.
1139 		 * This will succeed only when the socket is connected.
1140 		 */
1141 		ret = udp_sendmsg(sk, &msg, 0);
1142 		if (ret < 0)
1143 			return ret;
1144 	}
1145 
1146 	lock_sock(sk);
1147 
1148 	if (unlikely(!up->pending)) {
1149 		release_sock(sk);
1150 
1151 		net_dbg_ratelimited("cork failed\n");
1152 		return -EINVAL;
1153 	}
1154 
1155 	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1156 			     page, offset, size, flags);
1157 	if (ret == -EOPNOTSUPP) {
1158 		release_sock(sk);
1159 		return sock_no_sendpage(sk->sk_socket, page, offset,
1160 					size, flags);
1161 	}
1162 	if (ret < 0) {
1163 		udp_flush_pending_frames(sk);
1164 		goto out;
1165 	}
1166 
1167 	up->len += size;
1168 	if (!(up->corkflag || (flags&MSG_MORE)))
1169 		ret = udp_push_pending_frames(sk);
1170 	if (!ret)
1171 		ret = size;
1172 out:
1173 	release_sock(sk);
1174 	return ret;
1175 }
1176 
1177 #define UDP_SKB_IS_STATELESS 0x80000000
1178 
udp_set_dev_scratch(struct sk_buff * skb)1179 static void udp_set_dev_scratch(struct sk_buff *skb)
1180 {
1181 	struct udp_dev_scratch *scratch = udp_skb_scratch(skb);
1182 
1183 	BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long));
1184 	scratch->_tsize_state = skb->truesize;
1185 #if BITS_PER_LONG == 64
1186 	scratch->len = skb->len;
1187 	scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
1188 	scratch->is_linear = !skb_is_nonlinear(skb);
1189 #endif
1190 	/* all head states execept sp (dst, sk, nf) are always cleared by
1191 	 * udp_rcv() and we need to preserve secpath, if present, to eventually
1192 	 * process IP_CMSG_PASSSEC at recvmsg() time
1193 	 */
1194 	if (likely(!skb_sec_path(skb)))
1195 		scratch->_tsize_state |= UDP_SKB_IS_STATELESS;
1196 }
1197 
udp_skb_csum_unnecessary_set(struct sk_buff * skb)1198 static void udp_skb_csum_unnecessary_set(struct sk_buff *skb)
1199 {
1200 	/* We come here after udp_lib_checksum_complete() returned 0.
1201 	 * This means that __skb_checksum_complete() might have
1202 	 * set skb->csum_valid to 1.
1203 	 * On 64bit platforms, we can set csum_unnecessary
1204 	 * to true, but only if the skb is not shared.
1205 	 */
1206 #if BITS_PER_LONG == 64
1207 	if (!skb_shared(skb))
1208 		udp_skb_scratch(skb)->csum_unnecessary = true;
1209 #endif
1210 }
1211 
udp_skb_truesize(struct sk_buff * skb)1212 static int udp_skb_truesize(struct sk_buff *skb)
1213 {
1214 	return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS;
1215 }
1216 
udp_skb_has_head_state(struct sk_buff * skb)1217 static bool udp_skb_has_head_state(struct sk_buff *skb)
1218 {
1219 	return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS);
1220 }
1221 
1222 /* fully reclaim rmem/fwd memory allocated for skb */
udp_rmem_release(struct sock * sk,int size,int partial,bool rx_queue_lock_held)1223 static void udp_rmem_release(struct sock *sk, int size, int partial,
1224 			     bool rx_queue_lock_held)
1225 {
1226 	struct udp_sock *up = udp_sk(sk);
1227 	struct sk_buff_head *sk_queue;
1228 	int amt;
1229 
1230 	if (likely(partial)) {
1231 		up->forward_deficit += size;
1232 		size = up->forward_deficit;
1233 		if (size < (sk->sk_rcvbuf >> 2) &&
1234 		    !skb_queue_empty(&up->reader_queue))
1235 			return;
1236 	} else {
1237 		size += up->forward_deficit;
1238 	}
1239 	up->forward_deficit = 0;
1240 
1241 	/* acquire the sk_receive_queue for fwd allocated memory scheduling,
1242 	 * if the called don't held it already
1243 	 */
1244 	sk_queue = &sk->sk_receive_queue;
1245 	if (!rx_queue_lock_held)
1246 		spin_lock(&sk_queue->lock);
1247 
1248 
1249 	sk->sk_forward_alloc += size;
1250 	amt = (sk->sk_forward_alloc - partial) & ~(SK_MEM_QUANTUM - 1);
1251 	sk->sk_forward_alloc -= amt;
1252 
1253 	if (amt)
1254 		__sk_mem_reduce_allocated(sk, amt >> SK_MEM_QUANTUM_SHIFT);
1255 
1256 	atomic_sub(size, &sk->sk_rmem_alloc);
1257 
1258 	/* this can save us from acquiring the rx queue lock on next receive */
1259 	skb_queue_splice_tail_init(sk_queue, &up->reader_queue);
1260 
1261 	if (!rx_queue_lock_held)
1262 		spin_unlock(&sk_queue->lock);
1263 }
1264 
1265 /* Note: called with reader_queue.lock held.
1266  * Instead of using skb->truesize here, find a copy of it in skb->dev_scratch
1267  * This avoids a cache line miss while receive_queue lock is held.
1268  * Look at __udp_enqueue_schedule_skb() to find where this copy is done.
1269  */
udp_skb_destructor(struct sock * sk,struct sk_buff * skb)1270 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb)
1271 {
1272 	prefetch(&skb->data);
1273 	udp_rmem_release(sk, udp_skb_truesize(skb), 1, false);
1274 }
1275 EXPORT_SYMBOL(udp_skb_destructor);
1276 
1277 /* as above, but the caller held the rx queue lock, too */
udp_skb_dtor_locked(struct sock * sk,struct sk_buff * skb)1278 static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb)
1279 {
1280 	prefetch(&skb->data);
1281 	udp_rmem_release(sk, udp_skb_truesize(skb), 1, true);
1282 }
1283 
1284 /* Idea of busylocks is to let producers grab an extra spinlock
1285  * to relieve pressure on the receive_queue spinlock shared by consumer.
1286  * Under flood, this means that only one producer can be in line
1287  * trying to acquire the receive_queue spinlock.
1288  * These busylock can be allocated on a per cpu manner, instead of a
1289  * per socket one (that would consume a cache line per socket)
1290  */
1291 static int udp_busylocks_log __read_mostly;
1292 static spinlock_t *udp_busylocks __read_mostly;
1293 
busylock_acquire(void * ptr)1294 static spinlock_t *busylock_acquire(void *ptr)
1295 {
1296 	spinlock_t *busy;
1297 
1298 	busy = udp_busylocks + hash_ptr(ptr, udp_busylocks_log);
1299 	spin_lock(busy);
1300 	return busy;
1301 }
1302 
busylock_release(spinlock_t * busy)1303 static void busylock_release(spinlock_t *busy)
1304 {
1305 	if (busy)
1306 		spin_unlock(busy);
1307 }
1308 
__udp_enqueue_schedule_skb(struct sock * sk,struct sk_buff * skb)1309 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
1310 {
1311 	struct sk_buff_head *list = &sk->sk_receive_queue;
1312 	int rmem, delta, amt, err = -ENOMEM;
1313 	spinlock_t *busy = NULL;
1314 	int size;
1315 
1316 	/* try to avoid the costly atomic add/sub pair when the receive
1317 	 * queue is full; always allow at least a packet
1318 	 */
1319 	rmem = atomic_read(&sk->sk_rmem_alloc);
1320 	if (rmem > sk->sk_rcvbuf)
1321 		goto drop;
1322 
1323 	/* Under mem pressure, it might be helpful to help udp_recvmsg()
1324 	 * having linear skbs :
1325 	 * - Reduce memory overhead and thus increase receive queue capacity
1326 	 * - Less cache line misses at copyout() time
1327 	 * - Less work at consume_skb() (less alien page frag freeing)
1328 	 */
1329 	if (rmem > (sk->sk_rcvbuf >> 1)) {
1330 		skb_condense(skb);
1331 
1332 		busy = busylock_acquire(sk);
1333 	}
1334 	size = skb->truesize;
1335 	udp_set_dev_scratch(skb);
1336 
1337 	/* we drop only if the receive buf is full and the receive
1338 	 * queue contains some other skb
1339 	 */
1340 	rmem = atomic_add_return(size, &sk->sk_rmem_alloc);
1341 	if (rmem > (size + (unsigned int)sk->sk_rcvbuf))
1342 		goto uncharge_drop;
1343 
1344 	spin_lock(&list->lock);
1345 	if (size >= sk->sk_forward_alloc) {
1346 		amt = sk_mem_pages(size);
1347 		delta = amt << SK_MEM_QUANTUM_SHIFT;
1348 		if (!__sk_mem_raise_allocated(sk, delta, amt, SK_MEM_RECV)) {
1349 			err = -ENOBUFS;
1350 			spin_unlock(&list->lock);
1351 			goto uncharge_drop;
1352 		}
1353 
1354 		sk->sk_forward_alloc += delta;
1355 	}
1356 
1357 	sk->sk_forward_alloc -= size;
1358 
1359 	/* no need to setup a destructor, we will explicitly release the
1360 	 * forward allocated memory on dequeue
1361 	 */
1362 	sock_skb_set_dropcount(sk, skb);
1363 
1364 	__skb_queue_tail(list, skb);
1365 	spin_unlock(&list->lock);
1366 
1367 	if (!sock_flag(sk, SOCK_DEAD))
1368 		sk->sk_data_ready(sk);
1369 
1370 	busylock_release(busy);
1371 	return 0;
1372 
1373 uncharge_drop:
1374 	atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
1375 
1376 drop:
1377 	atomic_inc(&sk->sk_drops);
1378 	busylock_release(busy);
1379 	return err;
1380 }
1381 EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb);
1382 
udp_destruct_sock(struct sock * sk)1383 void udp_destruct_sock(struct sock *sk)
1384 {
1385 	/* reclaim completely the forward allocated memory */
1386 	struct udp_sock *up = udp_sk(sk);
1387 	unsigned int total = 0;
1388 	struct sk_buff *skb;
1389 
1390 	skb_queue_splice_tail_init(&sk->sk_receive_queue, &up->reader_queue);
1391 	while ((skb = __skb_dequeue(&up->reader_queue)) != NULL) {
1392 		total += skb->truesize;
1393 		kfree_skb(skb);
1394 	}
1395 	udp_rmem_release(sk, total, 0, true);
1396 
1397 	inet_sock_destruct(sk);
1398 }
1399 EXPORT_SYMBOL_GPL(udp_destruct_sock);
1400 
udp_init_sock(struct sock * sk)1401 int udp_init_sock(struct sock *sk)
1402 {
1403 	skb_queue_head_init(&udp_sk(sk)->reader_queue);
1404 	sk->sk_destruct = udp_destruct_sock;
1405 	return 0;
1406 }
1407 EXPORT_SYMBOL_GPL(udp_init_sock);
1408 
skb_consume_udp(struct sock * sk,struct sk_buff * skb,int len)1409 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
1410 {
1411 	if (unlikely(READ_ONCE(sk->sk_peek_off) >= 0)) {
1412 		bool slow = lock_sock_fast(sk);
1413 
1414 		sk_peek_offset_bwd(sk, len);
1415 		unlock_sock_fast(sk, slow);
1416 	}
1417 
1418 	if (!skb_unref(skb))
1419 		return;
1420 
1421 	/* In the more common cases we cleared the head states previously,
1422 	 * see __udp_queue_rcv_skb().
1423 	 */
1424 	if (unlikely(udp_skb_has_head_state(skb)))
1425 		skb_release_head_state(skb);
1426 	__consume_stateless_skb(skb);
1427 }
1428 EXPORT_SYMBOL_GPL(skb_consume_udp);
1429 
__first_packet_length(struct sock * sk,struct sk_buff_head * rcvq,int * total)1430 static struct sk_buff *__first_packet_length(struct sock *sk,
1431 					     struct sk_buff_head *rcvq,
1432 					     int *total)
1433 {
1434 	struct sk_buff *skb;
1435 
1436 	while ((skb = skb_peek(rcvq)) != NULL) {
1437 		if (udp_lib_checksum_complete(skb)) {
1438 			__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
1439 					IS_UDPLITE(sk));
1440 			__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
1441 					IS_UDPLITE(sk));
1442 			atomic_inc(&sk->sk_drops);
1443 			__skb_unlink(skb, rcvq);
1444 			*total += skb->truesize;
1445 			kfree_skb(skb);
1446 		} else {
1447 			udp_skb_csum_unnecessary_set(skb);
1448 			break;
1449 		}
1450 	}
1451 	return skb;
1452 }
1453 
1454 /**
1455  *	first_packet_length	- return length of first packet in receive queue
1456  *	@sk: socket
1457  *
1458  *	Drops all bad checksum frames, until a valid one is found.
1459  *	Returns the length of found skb, or -1 if none is found.
1460  */
first_packet_length(struct sock * sk)1461 static int first_packet_length(struct sock *sk)
1462 {
1463 	struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
1464 	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1465 	struct sk_buff *skb;
1466 	int total = 0;
1467 	int res;
1468 
1469 	spin_lock_bh(&rcvq->lock);
1470 	skb = __first_packet_length(sk, rcvq, &total);
1471 	if (!skb && !skb_queue_empty_lockless(sk_queue)) {
1472 		spin_lock(&sk_queue->lock);
1473 		skb_queue_splice_tail_init(sk_queue, rcvq);
1474 		spin_unlock(&sk_queue->lock);
1475 
1476 		skb = __first_packet_length(sk, rcvq, &total);
1477 	}
1478 	res = skb ? skb->len : -1;
1479 	if (total)
1480 		udp_rmem_release(sk, total, 1, false);
1481 	spin_unlock_bh(&rcvq->lock);
1482 	return res;
1483 }
1484 
1485 /*
1486  *	IOCTL requests applicable to the UDP protocol
1487  */
1488 
udp_ioctl(struct sock * sk,int cmd,unsigned long arg)1489 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1490 {
1491 	switch (cmd) {
1492 	case SIOCOUTQ:
1493 	{
1494 		int amount = sk_wmem_alloc_get(sk);
1495 
1496 		return put_user(amount, (int __user *)arg);
1497 	}
1498 
1499 	case SIOCINQ:
1500 	{
1501 		int amount = max_t(int, 0, first_packet_length(sk));
1502 
1503 		return put_user(amount, (int __user *)arg);
1504 	}
1505 
1506 	default:
1507 		return -ENOIOCTLCMD;
1508 	}
1509 
1510 	return 0;
1511 }
1512 EXPORT_SYMBOL(udp_ioctl);
1513 
__skb_recv_udp(struct sock * sk,unsigned int flags,int noblock,int * peeked,int * off,int * err)1514 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
1515 			       int noblock, int *peeked, int *off, int *err)
1516 {
1517 	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
1518 	struct sk_buff_head *queue;
1519 	struct sk_buff *last;
1520 	long timeo;
1521 	int error;
1522 
1523 	queue = &udp_sk(sk)->reader_queue;
1524 	flags |= noblock ? MSG_DONTWAIT : 0;
1525 	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
1526 	do {
1527 		struct sk_buff *skb;
1528 
1529 		error = sock_error(sk);
1530 		if (error)
1531 			break;
1532 
1533 		error = -EAGAIN;
1534 		*peeked = 0;
1535 		do {
1536 			spin_lock_bh(&queue->lock);
1537 			skb = __skb_try_recv_from_queue(sk, queue, flags,
1538 							udp_skb_destructor,
1539 							peeked, off, err,
1540 							&last);
1541 			if (skb) {
1542 				spin_unlock_bh(&queue->lock);
1543 				return skb;
1544 			}
1545 
1546 			if (skb_queue_empty_lockless(sk_queue)) {
1547 				spin_unlock_bh(&queue->lock);
1548 				goto busy_check;
1549 			}
1550 
1551 			/* refill the reader queue and walk it again
1552 			 * keep both queues locked to avoid re-acquiring
1553 			 * the sk_receive_queue lock if fwd memory scheduling
1554 			 * is needed.
1555 			 */
1556 			spin_lock(&sk_queue->lock);
1557 			skb_queue_splice_tail_init(sk_queue, queue);
1558 
1559 			skb = __skb_try_recv_from_queue(sk, queue, flags,
1560 							udp_skb_dtor_locked,
1561 							peeked, off, err,
1562 							&last);
1563 			spin_unlock(&sk_queue->lock);
1564 			spin_unlock_bh(&queue->lock);
1565 			if (skb)
1566 				return skb;
1567 
1568 busy_check:
1569 			if (!sk_can_busy_loop(sk))
1570 				break;
1571 
1572 			sk_busy_loop(sk, flags & MSG_DONTWAIT);
1573 		} while (!skb_queue_empty_lockless(sk_queue));
1574 
1575 		/* sk_queue is empty, reader_queue may contain peeked packets */
1576 	} while (timeo &&
1577 		 !__skb_wait_for_more_packets(sk, &error, &timeo,
1578 					      (struct sk_buff *)sk_queue));
1579 
1580 	*err = error;
1581 	return NULL;
1582 }
1583 EXPORT_SYMBOL(__skb_recv_udp);
1584 
1585 /*
1586  * 	This should be easy, if there is something there we
1587  * 	return it, otherwise we block.
1588  */
1589 
udp_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int noblock,int flags,int * addr_len)1590 int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
1591 		int flags, int *addr_len)
1592 {
1593 	struct inet_sock *inet = inet_sk(sk);
1594 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
1595 	struct sk_buff *skb;
1596 	unsigned int ulen, copied;
1597 	int peeked, peeking, off;
1598 	int err;
1599 	int is_udplite = IS_UDPLITE(sk);
1600 	bool checksum_valid = false;
1601 
1602 	if (flags & MSG_ERRQUEUE)
1603 		return ip_recv_error(sk, msg, len, addr_len);
1604 
1605 try_again:
1606 	peeking = flags & MSG_PEEK;
1607 	off = sk_peek_offset(sk, flags);
1608 	skb = __skb_recv_udp(sk, flags, noblock, &peeked, &off, &err);
1609 	if (!skb)
1610 		return err;
1611 
1612 	ulen = udp_skb_len(skb);
1613 	copied = len;
1614 	if (copied > ulen - off)
1615 		copied = ulen - off;
1616 	else if (copied < ulen)
1617 		msg->msg_flags |= MSG_TRUNC;
1618 
1619 	/*
1620 	 * If checksum is needed at all, try to do it while copying the
1621 	 * data.  If the data is truncated, or if we only want a partial
1622 	 * coverage checksum (UDP-Lite), do it before the copy.
1623 	 */
1624 
1625 	if (copied < ulen || peeking ||
1626 	    (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
1627 		checksum_valid = udp_skb_csum_unnecessary(skb) ||
1628 				!__udp_lib_checksum_complete(skb);
1629 		if (!checksum_valid)
1630 			goto csum_copy_err;
1631 	}
1632 
1633 	if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
1634 		if (udp_skb_is_linear(skb))
1635 			err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
1636 		else
1637 			err = skb_copy_datagram_msg(skb, off, msg, copied);
1638 	} else {
1639 		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
1640 
1641 		if (err == -EINVAL)
1642 			goto csum_copy_err;
1643 	}
1644 
1645 	if (unlikely(err)) {
1646 		if (!peeked) {
1647 			atomic_inc(&sk->sk_drops);
1648 			UDP_INC_STATS(sock_net(sk),
1649 				      UDP_MIB_INERRORS, is_udplite);
1650 		}
1651 		kfree_skb(skb);
1652 		return err;
1653 	}
1654 
1655 	if (!peeked)
1656 		UDP_INC_STATS(sock_net(sk),
1657 			      UDP_MIB_INDATAGRAMS, is_udplite);
1658 
1659 	sock_recv_ts_and_drops(msg, sk, skb);
1660 
1661 	/* Copy the address. */
1662 	if (sin) {
1663 		sin->sin_family = AF_INET;
1664 		sin->sin_port = udp_hdr(skb)->source;
1665 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1666 		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1667 		*addr_len = sizeof(*sin);
1668 	}
1669 	if (inet->cmsg_flags)
1670 		ip_cmsg_recv_offset(msg, sk, skb, sizeof(struct udphdr), off);
1671 
1672 	err = copied;
1673 	if (flags & MSG_TRUNC)
1674 		err = ulen;
1675 
1676 	skb_consume_udp(sk, skb, peeking ? -err : err);
1677 	return err;
1678 
1679 csum_copy_err:
1680 	if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
1681 				 udp_skb_destructor)) {
1682 		UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1683 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1684 	}
1685 	kfree_skb(skb);
1686 
1687 	/* starting over for a new packet, but check if we need to yield */
1688 	cond_resched();
1689 	msg->msg_flags &= ~MSG_TRUNC;
1690 	goto try_again;
1691 }
1692 
__udp_disconnect(struct sock * sk,int flags)1693 int __udp_disconnect(struct sock *sk, int flags)
1694 {
1695 	struct inet_sock *inet = inet_sk(sk);
1696 	/*
1697 	 *	1003.1g - break association.
1698 	 */
1699 
1700 	sk->sk_state = TCP_CLOSE;
1701 	inet->inet_daddr = 0;
1702 	inet->inet_dport = 0;
1703 	sock_rps_reset_rxhash(sk);
1704 	sk->sk_bound_dev_if = 0;
1705 	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1706 		inet_reset_saddr(sk);
1707 
1708 	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1709 		sk->sk_prot->unhash(sk);
1710 		inet->inet_sport = 0;
1711 	}
1712 	sk_dst_reset(sk);
1713 	return 0;
1714 }
1715 EXPORT_SYMBOL(__udp_disconnect);
1716 
udp_disconnect(struct sock * sk,int flags)1717 int udp_disconnect(struct sock *sk, int flags)
1718 {
1719 	lock_sock(sk);
1720 	__udp_disconnect(sk, flags);
1721 	release_sock(sk);
1722 	return 0;
1723 }
1724 EXPORT_SYMBOL(udp_disconnect);
1725 
udp_lib_unhash(struct sock * sk)1726 void udp_lib_unhash(struct sock *sk)
1727 {
1728 	if (sk_hashed(sk)) {
1729 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1730 		struct udp_hslot *hslot, *hslot2;
1731 
1732 		hslot  = udp_hashslot(udptable, sock_net(sk),
1733 				      udp_sk(sk)->udp_port_hash);
1734 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1735 
1736 		spin_lock_bh(&hslot->lock);
1737 		if (rcu_access_pointer(sk->sk_reuseport_cb))
1738 			reuseport_detach_sock(sk);
1739 		if (sk_del_node_init_rcu(sk)) {
1740 			hslot->count--;
1741 			inet_sk(sk)->inet_num = 0;
1742 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1743 
1744 			spin_lock(&hslot2->lock);
1745 			hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1746 			hslot2->count--;
1747 			spin_unlock(&hslot2->lock);
1748 		}
1749 		spin_unlock_bh(&hslot->lock);
1750 	}
1751 }
1752 EXPORT_SYMBOL(udp_lib_unhash);
1753 
1754 /*
1755  * inet_rcv_saddr was changed, we must rehash secondary hash
1756  */
udp_lib_rehash(struct sock * sk,u16 newhash)1757 void udp_lib_rehash(struct sock *sk, u16 newhash)
1758 {
1759 	if (sk_hashed(sk)) {
1760 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1761 		struct udp_hslot *hslot, *hslot2, *nhslot2;
1762 
1763 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1764 		nhslot2 = udp_hashslot2(udptable, newhash);
1765 		udp_sk(sk)->udp_portaddr_hash = newhash;
1766 
1767 		if (hslot2 != nhslot2 ||
1768 		    rcu_access_pointer(sk->sk_reuseport_cb)) {
1769 			hslot = udp_hashslot(udptable, sock_net(sk),
1770 					     udp_sk(sk)->udp_port_hash);
1771 			/* we must lock primary chain too */
1772 			spin_lock_bh(&hslot->lock);
1773 			if (rcu_access_pointer(sk->sk_reuseport_cb))
1774 				reuseport_detach_sock(sk);
1775 
1776 			if (hslot2 != nhslot2) {
1777 				spin_lock(&hslot2->lock);
1778 				hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1779 				hslot2->count--;
1780 				spin_unlock(&hslot2->lock);
1781 
1782 				spin_lock(&nhslot2->lock);
1783 				hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1784 							 &nhslot2->head);
1785 				nhslot2->count++;
1786 				spin_unlock(&nhslot2->lock);
1787 			}
1788 
1789 			spin_unlock_bh(&hslot->lock);
1790 		}
1791 	}
1792 }
1793 EXPORT_SYMBOL(udp_lib_rehash);
1794 
udp_v4_rehash(struct sock * sk)1795 static void udp_v4_rehash(struct sock *sk)
1796 {
1797 	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1798 					  inet_sk(sk)->inet_rcv_saddr,
1799 					  inet_sk(sk)->inet_num);
1800 	udp_lib_rehash(sk, new_hash);
1801 }
1802 
__udp_queue_rcv_skb(struct sock * sk,struct sk_buff * skb)1803 static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1804 {
1805 	int rc;
1806 
1807 	if (inet_sk(sk)->inet_daddr) {
1808 		sock_rps_save_rxhash(sk, skb);
1809 		sk_mark_napi_id(sk, skb);
1810 		sk_incoming_cpu_update(sk);
1811 	} else {
1812 		sk_mark_napi_id_once(sk, skb);
1813 	}
1814 
1815 	rc = __udp_enqueue_schedule_skb(sk, skb);
1816 	if (rc < 0) {
1817 		int is_udplite = IS_UDPLITE(sk);
1818 
1819 		/* Note that an ENOMEM error is charged twice */
1820 		if (rc == -ENOMEM)
1821 			UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1822 					is_udplite);
1823 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1824 		kfree_skb(skb);
1825 		trace_udp_fail_queue_rcv_skb(rc, sk);
1826 		return -1;
1827 	}
1828 
1829 	return 0;
1830 }
1831 
1832 static struct static_key udp_encap_needed __read_mostly;
udp_encap_enable(void)1833 void udp_encap_enable(void)
1834 {
1835 	static_key_enable(&udp_encap_needed);
1836 }
1837 EXPORT_SYMBOL(udp_encap_enable);
1838 
1839 /* returns:
1840  *  -1: error
1841  *   0: success
1842  *  >0: "udp encap" protocol resubmission
1843  *
1844  * Note that in the success and error cases, the skb is assumed to
1845  * have either been requeued or freed.
1846  */
udp_queue_rcv_skb(struct sock * sk,struct sk_buff * skb)1847 static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1848 {
1849 	struct udp_sock *up = udp_sk(sk);
1850 	int is_udplite = IS_UDPLITE(sk);
1851 
1852 	/*
1853 	 *	Charge it to the socket, dropping if the queue is full.
1854 	 */
1855 	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1856 		goto drop;
1857 	nf_reset(skb);
1858 
1859 	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1860 		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
1861 
1862 		/*
1863 		 * This is an encapsulation socket so pass the skb to
1864 		 * the socket's udp_encap_rcv() hook. Otherwise, just
1865 		 * fall through and pass this up the UDP socket.
1866 		 * up->encap_rcv() returns the following value:
1867 		 * =0 if skb was successfully passed to the encap
1868 		 *    handler or was discarded by it.
1869 		 * >0 if skb should be passed on to UDP.
1870 		 * <0 if skb should be resubmitted as proto -N
1871 		 */
1872 
1873 		/* if we're overly short, let UDP handle it */
1874 		encap_rcv = ACCESS_ONCE(up->encap_rcv);
1875 		if (encap_rcv) {
1876 			int ret;
1877 
1878 			/* Verify checksum before giving to encap */
1879 			if (udp_lib_checksum_complete(skb))
1880 				goto csum_error;
1881 
1882 			ret = encap_rcv(sk, skb);
1883 			if (ret <= 0) {
1884 				__UDP_INC_STATS(sock_net(sk),
1885 						UDP_MIB_INDATAGRAMS,
1886 						is_udplite);
1887 				return -ret;
1888 			}
1889 		}
1890 
1891 		/* FALLTHROUGH -- it's a UDP Packet */
1892 	}
1893 
1894 	/*
1895 	 * 	UDP-Lite specific tests, ignored on UDP sockets
1896 	 */
1897 	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
1898 
1899 		/*
1900 		 * MIB statistics other than incrementing the error count are
1901 		 * disabled for the following two types of errors: these depend
1902 		 * on the application settings, not on the functioning of the
1903 		 * protocol stack as such.
1904 		 *
1905 		 * RFC 3828 here recommends (sec 3.3): "There should also be a
1906 		 * way ... to ... at least let the receiving application block
1907 		 * delivery of packets with coverage values less than a value
1908 		 * provided by the application."
1909 		 */
1910 		if (up->pcrlen == 0) {          /* full coverage was set  */
1911 			net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
1912 					    UDP_SKB_CB(skb)->cscov, skb->len);
1913 			goto drop;
1914 		}
1915 		/* The next case involves violating the min. coverage requested
1916 		 * by the receiver. This is subtle: if receiver wants x and x is
1917 		 * greater than the buffersize/MTU then receiver will complain
1918 		 * that it wants x while sender emits packets of smaller size y.
1919 		 * Therefore the above ...()->partial_cov statement is essential.
1920 		 */
1921 		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1922 			net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
1923 					    UDP_SKB_CB(skb)->cscov, up->pcrlen);
1924 			goto drop;
1925 		}
1926 	}
1927 
1928 	prefetch(&sk->sk_rmem_alloc);
1929 	if (rcu_access_pointer(sk->sk_filter) &&
1930 	    udp_lib_checksum_complete(skb))
1931 			goto csum_error;
1932 
1933 	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
1934 		goto drop;
1935 
1936 	udp_csum_pull_header(skb);
1937 
1938 	ipv4_pktinfo_prepare(sk, skb);
1939 	return __udp_queue_rcv_skb(sk, skb);
1940 
1941 csum_error:
1942 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1943 drop:
1944 	__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1945 	atomic_inc(&sk->sk_drops);
1946 	kfree_skb(skb);
1947 	return -1;
1948 }
1949 
1950 /* For TCP sockets, sk_rx_dst is protected by socket lock
1951  * For UDP, we use xchg() to guard against concurrent changes.
1952  */
udp_sk_rx_dst_set(struct sock * sk,struct dst_entry * dst)1953 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
1954 {
1955 	struct dst_entry *old;
1956 
1957 	if (dst_hold_safe(dst)) {
1958 		old = xchg(&sk->sk_rx_dst, dst);
1959 		dst_release(old);
1960 		return old != dst;
1961 	}
1962 	return false;
1963 }
1964 EXPORT_SYMBOL(udp_sk_rx_dst_set);
1965 
1966 /*
1967  *	Multicasts and broadcasts go to each listener.
1968  *
1969  *	Note: called only from the BH handler context.
1970  */
__udp4_lib_mcast_deliver(struct net * net,struct sk_buff * skb,struct udphdr * uh,__be32 saddr,__be32 daddr,struct udp_table * udptable,int proto)1971 static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1972 				    struct udphdr  *uh,
1973 				    __be32 saddr, __be32 daddr,
1974 				    struct udp_table *udptable,
1975 				    int proto)
1976 {
1977 	struct sock *sk, *first = NULL;
1978 	unsigned short hnum = ntohs(uh->dest);
1979 	struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
1980 	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
1981 	unsigned int offset = offsetof(typeof(*sk), sk_node);
1982 	int dif = skb->dev->ifindex;
1983 	int sdif = inet_sdif(skb);
1984 	struct hlist_node *node;
1985 	struct sk_buff *nskb;
1986 
1987 	if (use_hash2) {
1988 		hash2_any = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
1989 			    udptable->mask;
1990 		hash2 = udp4_portaddr_hash(net, daddr, hnum) & udptable->mask;
1991 start_lookup:
1992 		hslot = &udptable->hash2[hash2];
1993 		offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
1994 	}
1995 
1996 	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
1997 		if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr,
1998 					 uh->source, saddr, dif, sdif, hnum))
1999 			continue;
2000 
2001 		if (!first) {
2002 			first = sk;
2003 			continue;
2004 		}
2005 		nskb = skb_clone(skb, GFP_ATOMIC);
2006 
2007 		if (unlikely(!nskb)) {
2008 			atomic_inc(&sk->sk_drops);
2009 			__UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
2010 					IS_UDPLITE(sk));
2011 			__UDP_INC_STATS(net, UDP_MIB_INERRORS,
2012 					IS_UDPLITE(sk));
2013 			continue;
2014 		}
2015 		if (udp_queue_rcv_skb(sk, nskb) > 0)
2016 			consume_skb(nskb);
2017 	}
2018 
2019 	/* Also lookup *:port if we are using hash2 and haven't done so yet. */
2020 	if (use_hash2 && hash2 != hash2_any) {
2021 		hash2 = hash2_any;
2022 		goto start_lookup;
2023 	}
2024 
2025 	if (first) {
2026 		if (udp_queue_rcv_skb(first, skb) > 0)
2027 			consume_skb(skb);
2028 	} else {
2029 		kfree_skb(skb);
2030 		__UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
2031 				proto == IPPROTO_UDPLITE);
2032 	}
2033 	return 0;
2034 }
2035 
2036 /* Initialize UDP checksum. If exited with zero value (success),
2037  * CHECKSUM_UNNECESSARY means, that no more checks are required.
2038  * Otherwise, csum completion requires chacksumming packet body,
2039  * including udp header and folding it to skb->csum.
2040  */
udp4_csum_init(struct sk_buff * skb,struct udphdr * uh,int proto)2041 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
2042 				 int proto)
2043 {
2044 	int err;
2045 
2046 	UDP_SKB_CB(skb)->partial_cov = 0;
2047 	UDP_SKB_CB(skb)->cscov = skb->len;
2048 
2049 	if (proto == IPPROTO_UDPLITE) {
2050 		err = udplite_checksum_init(skb, uh);
2051 		if (err)
2052 			return err;
2053 
2054 		if (UDP_SKB_CB(skb)->partial_cov) {
2055 			skb->csum = inet_compute_pseudo(skb, proto);
2056 			return 0;
2057 		}
2058 	}
2059 
2060 	/* Note, we are only interested in != 0 or == 0, thus the
2061 	 * force to int.
2062 	 */
2063 	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
2064 							inet_compute_pseudo);
2065 	if (err)
2066 		return err;
2067 
2068 	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
2069 		/* If SW calculated the value, we know it's bad */
2070 		if (skb->csum_complete_sw)
2071 			return 1;
2072 
2073 		/* HW says the value is bad. Let's validate that.
2074 		 * skb->csum is no longer the full packet checksum,
2075 		 * so don't treat it as such.
2076 		 */
2077 		skb_checksum_complete_unset(skb);
2078 	}
2079 
2080 	return 0;
2081 }
2082 
2083 /* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
2084  * return code conversion for ip layer consumption
2085  */
udp_unicast_rcv_skb(struct sock * sk,struct sk_buff * skb,struct udphdr * uh)2086 static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
2087 			       struct udphdr *uh)
2088 {
2089 	int ret;
2090 
2091 	if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
2092 		skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
2093 					 inet_compute_pseudo);
2094 
2095 	ret = udp_queue_rcv_skb(sk, skb);
2096 
2097 	/* a return value > 0 means to resubmit the input, but
2098 	 * it wants the return to be -protocol, or 0
2099 	 */
2100 	if (ret > 0)
2101 		return -ret;
2102 	return 0;
2103 }
2104 
2105 /*
2106  *	All we need to do is get the socket, and then do a checksum.
2107  */
2108 
__udp4_lib_rcv(struct sk_buff * skb,struct udp_table * udptable,int proto)2109 int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
2110 		   int proto)
2111 {
2112 	struct sock *sk;
2113 	struct udphdr *uh;
2114 	unsigned short ulen;
2115 	struct rtable *rt = skb_rtable(skb);
2116 	__be32 saddr, daddr;
2117 	struct net *net = dev_net(skb->dev);
2118 
2119 	/*
2120 	 *  Validate the packet.
2121 	 */
2122 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
2123 		goto drop;		/* No space for header. */
2124 
2125 	uh   = udp_hdr(skb);
2126 	ulen = ntohs(uh->len);
2127 	saddr = ip_hdr(skb)->saddr;
2128 	daddr = ip_hdr(skb)->daddr;
2129 
2130 	if (ulen > skb->len)
2131 		goto short_packet;
2132 
2133 	if (proto == IPPROTO_UDP) {
2134 		/* UDP validates ulen. */
2135 		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
2136 			goto short_packet;
2137 		uh = udp_hdr(skb);
2138 	}
2139 
2140 	if (udp4_csum_init(skb, uh, proto))
2141 		goto csum_error;
2142 
2143 	sk = skb_steal_sock(skb);
2144 	if (sk) {
2145 		struct dst_entry *dst = skb_dst(skb);
2146 		int ret;
2147 
2148 		if (unlikely(sk->sk_rx_dst != dst))
2149 			udp_sk_rx_dst_set(sk, dst);
2150 
2151 		ret = udp_unicast_rcv_skb(sk, skb, uh);
2152 		sock_put(sk);
2153 		return ret;
2154 	}
2155 
2156 	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
2157 		return __udp4_lib_mcast_deliver(net, skb, uh,
2158 						saddr, daddr, udptable, proto);
2159 
2160 	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
2161 	if (sk)
2162 		return udp_unicast_rcv_skb(sk, skb, uh);
2163 
2164 	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
2165 		goto drop;
2166 	nf_reset(skb);
2167 
2168 	/* No socket. Drop packet silently, if checksum is wrong */
2169 	if (udp_lib_checksum_complete(skb))
2170 		goto csum_error;
2171 
2172 	__UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
2173 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
2174 
2175 	/*
2176 	 * Hmm.  We got an UDP packet to a port to which we
2177 	 * don't wanna listen.  Ignore it.
2178 	 */
2179 	kfree_skb(skb);
2180 	return 0;
2181 
2182 short_packet:
2183 	net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
2184 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
2185 			    &saddr, ntohs(uh->source),
2186 			    ulen, skb->len,
2187 			    &daddr, ntohs(uh->dest));
2188 	goto drop;
2189 
2190 csum_error:
2191 	/*
2192 	 * RFC1122: OK.  Discards the bad packet silently (as far as
2193 	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
2194 	 */
2195 	net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
2196 			    proto == IPPROTO_UDPLITE ? "Lite" : "",
2197 			    &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
2198 			    ulen);
2199 	__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
2200 drop:
2201 	__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
2202 	kfree_skb(skb);
2203 	return 0;
2204 }
2205 
2206 /* We can only early demux multicast if there is a single matching socket.
2207  * If more than one socket found returns NULL
2208  */
__udp4_lib_mcast_demux_lookup(struct net * net,__be16 loc_port,__be32 loc_addr,__be16 rmt_port,__be32 rmt_addr,int dif,int sdif)2209 static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
2210 						  __be16 loc_port, __be32 loc_addr,
2211 						  __be16 rmt_port, __be32 rmt_addr,
2212 						  int dif, int sdif)
2213 {
2214 	struct sock *sk, *result;
2215 	unsigned short hnum = ntohs(loc_port);
2216 	unsigned int slot = udp_hashfn(net, hnum, udp_table.mask);
2217 	struct udp_hslot *hslot = &udp_table.hash[slot];
2218 
2219 	/* Do not bother scanning a too big list */
2220 	if (hslot->count > 10)
2221 		return NULL;
2222 
2223 	result = NULL;
2224 	sk_for_each_rcu(sk, &hslot->head) {
2225 		if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
2226 					rmt_port, rmt_addr, dif, sdif, hnum)) {
2227 			if (result)
2228 				return NULL;
2229 			result = sk;
2230 		}
2231 	}
2232 
2233 	return result;
2234 }
2235 
2236 /* For unicast we should only early demux connected sockets or we can
2237  * break forwarding setups.  The chains here can be long so only check
2238  * if the first socket is an exact match and if not move on.
2239  */
__udp4_lib_demux_lookup(struct net * net,__be16 loc_port,__be32 loc_addr,__be16 rmt_port,__be32 rmt_addr,int dif,int sdif)2240 static struct sock *__udp4_lib_demux_lookup(struct net *net,
2241 					    __be16 loc_port, __be32 loc_addr,
2242 					    __be16 rmt_port, __be32 rmt_addr,
2243 					    int dif, int sdif)
2244 {
2245 	unsigned short hnum = ntohs(loc_port);
2246 	unsigned int hash2 = udp4_portaddr_hash(net, loc_addr, hnum);
2247 	unsigned int slot2 = hash2 & udp_table.mask;
2248 	struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
2249 	INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
2250 	const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
2251 	struct sock *sk;
2252 
2253 	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
2254 		if (INET_MATCH(sk, net, acookie, rmt_addr,
2255 			       loc_addr, ports, dif, sdif))
2256 			return sk;
2257 		/* Only check first socket in chain */
2258 		break;
2259 	}
2260 	return NULL;
2261 }
2262 
udp_v4_early_demux(struct sk_buff * skb)2263 int udp_v4_early_demux(struct sk_buff *skb)
2264 {
2265 	struct net *net = dev_net(skb->dev);
2266 	struct in_device *in_dev = NULL;
2267 	const struct iphdr *iph;
2268 	const struct udphdr *uh;
2269 	struct sock *sk = NULL;
2270 	struct dst_entry *dst;
2271 	int dif = skb->dev->ifindex;
2272 	int sdif = inet_sdif(skb);
2273 	int ours;
2274 
2275 	/* validate the packet */
2276 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
2277 		return 0;
2278 
2279 	iph = ip_hdr(skb);
2280 	uh = udp_hdr(skb);
2281 
2282 	if (skb->pkt_type == PACKET_MULTICAST) {
2283 		in_dev = __in_dev_get_rcu(skb->dev);
2284 
2285 		if (!in_dev)
2286 			return 0;
2287 
2288 		ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
2289 				       iph->protocol);
2290 		if (!ours)
2291 			return 0;
2292 
2293 		sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
2294 						   uh->source, iph->saddr,
2295 						   dif, sdif);
2296 	} else if (skb->pkt_type == PACKET_HOST) {
2297 		sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
2298 					     uh->source, iph->saddr, dif, sdif);
2299 	}
2300 
2301 	if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
2302 		return 0;
2303 
2304 	skb->sk = sk;
2305 	skb->destructor = sock_efree;
2306 	dst = READ_ONCE(sk->sk_rx_dst);
2307 
2308 	if (dst)
2309 		dst = dst_check(dst, 0);
2310 	if (dst) {
2311 		u32 itag = 0;
2312 
2313 		/* set noref for now.
2314 		 * any place which wants to hold dst has to call
2315 		 * dst_hold_safe()
2316 		 */
2317 		skb_dst_set_noref(skb, dst);
2318 
2319 		/* for unconnected multicast sockets we need to validate
2320 		 * the source on each packet
2321 		 */
2322 		if (!inet_sk(sk)->inet_daddr && in_dev)
2323 			return ip_mc_validate_source(skb, iph->daddr,
2324 						     iph->saddr, iph->tos,
2325 						     skb->dev, in_dev, &itag);
2326 	}
2327 	return 0;
2328 }
2329 
udp_rcv(struct sk_buff * skb)2330 int udp_rcv(struct sk_buff *skb)
2331 {
2332 	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
2333 }
2334 
udp_destroy_sock(struct sock * sk)2335 void udp_destroy_sock(struct sock *sk)
2336 {
2337 	struct udp_sock *up = udp_sk(sk);
2338 	bool slow = lock_sock_fast(sk);
2339 	udp_flush_pending_frames(sk);
2340 	unlock_sock_fast(sk, slow);
2341 	if (static_key_false(&udp_encap_needed) && up->encap_type) {
2342 		void (*encap_destroy)(struct sock *sk);
2343 		encap_destroy = ACCESS_ONCE(up->encap_destroy);
2344 		if (encap_destroy)
2345 			encap_destroy(sk);
2346 	}
2347 }
2348 
2349 /*
2350  *	Socket option code for UDP
2351  */
udp_lib_setsockopt(struct sock * sk,int level,int optname,char __user * optval,unsigned int optlen,int (* push_pending_frames)(struct sock *))2352 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
2353 		       char __user *optval, unsigned int optlen,
2354 		       int (*push_pending_frames)(struct sock *))
2355 {
2356 	struct udp_sock *up = udp_sk(sk);
2357 	int val, valbool;
2358 	int err = 0;
2359 	int is_udplite = IS_UDPLITE(sk);
2360 
2361 	if (optlen < sizeof(int))
2362 		return -EINVAL;
2363 
2364 	if (get_user(val, (int __user *)optval))
2365 		return -EFAULT;
2366 
2367 	valbool = val ? 1 : 0;
2368 
2369 	switch (optname) {
2370 	case UDP_CORK:
2371 		if (val != 0) {
2372 			up->corkflag = 1;
2373 		} else {
2374 			up->corkflag = 0;
2375 			lock_sock(sk);
2376 			push_pending_frames(sk);
2377 			release_sock(sk);
2378 		}
2379 		break;
2380 
2381 	case UDP_ENCAP:
2382 		switch (val) {
2383 		case 0:
2384 		case UDP_ENCAP_ESPINUDP:
2385 		case UDP_ENCAP_ESPINUDP_NON_IKE:
2386 			up->encap_rcv = xfrm4_udp_encap_rcv;
2387 			/* FALLTHROUGH */
2388 		case UDP_ENCAP_L2TPINUDP:
2389 			up->encap_type = val;
2390 			udp_encap_enable();
2391 			break;
2392 		default:
2393 			err = -ENOPROTOOPT;
2394 			break;
2395 		}
2396 		break;
2397 
2398 	case UDP_NO_CHECK6_TX:
2399 		up->no_check6_tx = valbool;
2400 		break;
2401 
2402 	case UDP_NO_CHECK6_RX:
2403 		up->no_check6_rx = valbool;
2404 		break;
2405 
2406 	/*
2407 	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
2408 	 */
2409 	/* The sender sets actual checksum coverage length via this option.
2410 	 * The case coverage > packet length is handled by send module. */
2411 	case UDPLITE_SEND_CSCOV:
2412 		if (!is_udplite)         /* Disable the option on UDP sockets */
2413 			return -ENOPROTOOPT;
2414 		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
2415 			val = 8;
2416 		else if (val > USHRT_MAX)
2417 			val = USHRT_MAX;
2418 		up->pcslen = val;
2419 		up->pcflag |= UDPLITE_SEND_CC;
2420 		break;
2421 
2422 	/* The receiver specifies a minimum checksum coverage value. To make
2423 	 * sense, this should be set to at least 8 (as done below). If zero is
2424 	 * used, this again means full checksum coverage.                     */
2425 	case UDPLITE_RECV_CSCOV:
2426 		if (!is_udplite)         /* Disable the option on UDP sockets */
2427 			return -ENOPROTOOPT;
2428 		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
2429 			val = 8;
2430 		else if (val > USHRT_MAX)
2431 			val = USHRT_MAX;
2432 		up->pcrlen = val;
2433 		up->pcflag |= UDPLITE_RECV_CC;
2434 		break;
2435 
2436 	default:
2437 		err = -ENOPROTOOPT;
2438 		break;
2439 	}
2440 
2441 	return err;
2442 }
2443 EXPORT_SYMBOL(udp_lib_setsockopt);
2444 
udp_setsockopt(struct sock * sk,int level,int optname,char __user * optval,unsigned int optlen)2445 int udp_setsockopt(struct sock *sk, int level, int optname,
2446 		   char __user *optval, unsigned int optlen)
2447 {
2448 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2449 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2450 					  udp_push_pending_frames);
2451 	return ip_setsockopt(sk, level, optname, optval, optlen);
2452 }
2453 
2454 #ifdef CONFIG_COMPAT
compat_udp_setsockopt(struct sock * sk,int level,int optname,char __user * optval,unsigned int optlen)2455 int compat_udp_setsockopt(struct sock *sk, int level, int optname,
2456 			  char __user *optval, unsigned int optlen)
2457 {
2458 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2459 		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2460 					  udp_push_pending_frames);
2461 	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
2462 }
2463 #endif
2464 
udp_lib_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)2465 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
2466 		       char __user *optval, int __user *optlen)
2467 {
2468 	struct udp_sock *up = udp_sk(sk);
2469 	int val, len;
2470 
2471 	if (get_user(len, optlen))
2472 		return -EFAULT;
2473 
2474 	len = min_t(unsigned int, len, sizeof(int));
2475 
2476 	if (len < 0)
2477 		return -EINVAL;
2478 
2479 	switch (optname) {
2480 	case UDP_CORK:
2481 		val = up->corkflag;
2482 		break;
2483 
2484 	case UDP_ENCAP:
2485 		val = up->encap_type;
2486 		break;
2487 
2488 	case UDP_NO_CHECK6_TX:
2489 		val = up->no_check6_tx;
2490 		break;
2491 
2492 	case UDP_NO_CHECK6_RX:
2493 		val = up->no_check6_rx;
2494 		break;
2495 
2496 	/* The following two cannot be changed on UDP sockets, the return is
2497 	 * always 0 (which corresponds to the full checksum coverage of UDP). */
2498 	case UDPLITE_SEND_CSCOV:
2499 		val = up->pcslen;
2500 		break;
2501 
2502 	case UDPLITE_RECV_CSCOV:
2503 		val = up->pcrlen;
2504 		break;
2505 
2506 	default:
2507 		return -ENOPROTOOPT;
2508 	}
2509 
2510 	if (put_user(len, optlen))
2511 		return -EFAULT;
2512 	if (copy_to_user(optval, &val, len))
2513 		return -EFAULT;
2514 	return 0;
2515 }
2516 EXPORT_SYMBOL(udp_lib_getsockopt);
2517 
udp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)2518 int udp_getsockopt(struct sock *sk, int level, int optname,
2519 		   char __user *optval, int __user *optlen)
2520 {
2521 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2522 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2523 	return ip_getsockopt(sk, level, optname, optval, optlen);
2524 }
2525 
2526 #ifdef CONFIG_COMPAT
compat_udp_getsockopt(struct sock * sk,int level,int optname,char __user * optval,int __user * optlen)2527 int compat_udp_getsockopt(struct sock *sk, int level, int optname,
2528 				 char __user *optval, int __user *optlen)
2529 {
2530 	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2531 		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2532 	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
2533 }
2534 #endif
2535 /**
2536  * 	udp_poll - wait for a UDP event.
2537  *	@file - file struct
2538  *	@sock - socket
2539  *	@wait - poll table
2540  *
2541  *	This is same as datagram poll, except for the special case of
2542  *	blocking sockets. If application is using a blocking fd
2543  *	and a packet with checksum error is in the queue;
2544  *	then it could get return from select indicating data available
2545  *	but then block when reading it. Add special case code
2546  *	to work around these arguably broken applications.
2547  */
udp_poll(struct file * file,struct socket * sock,poll_table * wait)2548 unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
2549 {
2550 	unsigned int mask = datagram_poll(file, sock, wait);
2551 	struct sock *sk = sock->sk;
2552 
2553 	if (!skb_queue_empty_lockless(&udp_sk(sk)->reader_queue))
2554 		mask |= POLLIN | POLLRDNORM;
2555 
2556 	sock_rps_record_flow(sk);
2557 
2558 	/* Check for false positives due to checksum errors */
2559 	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
2560 	    !(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)
2561 		mask &= ~(POLLIN | POLLRDNORM);
2562 
2563 	return mask;
2564 
2565 }
2566 EXPORT_SYMBOL(udp_poll);
2567 
udp_abort(struct sock * sk,int err)2568 int udp_abort(struct sock *sk, int err)
2569 {
2570 	lock_sock(sk);
2571 
2572 	sk->sk_err = err;
2573 	sk->sk_error_report(sk);
2574 	__udp_disconnect(sk, 0);
2575 
2576 	release_sock(sk);
2577 
2578 	return 0;
2579 }
2580 EXPORT_SYMBOL_GPL(udp_abort);
2581 
2582 struct proto udp_prot = {
2583 	.name		   = "UDP",
2584 	.owner		   = THIS_MODULE,
2585 	.close		   = udp_lib_close,
2586 	.connect	   = ip4_datagram_connect,
2587 	.disconnect	   = udp_disconnect,
2588 	.ioctl		   = udp_ioctl,
2589 	.init		   = udp_init_sock,
2590 	.destroy	   = udp_destroy_sock,
2591 	.setsockopt	   = udp_setsockopt,
2592 	.getsockopt	   = udp_getsockopt,
2593 	.sendmsg	   = udp_sendmsg,
2594 	.recvmsg	   = udp_recvmsg,
2595 	.sendpage	   = udp_sendpage,
2596 	.release_cb	   = ip4_datagram_release_cb,
2597 	.hash		   = udp_lib_hash,
2598 	.unhash		   = udp_lib_unhash,
2599 	.rehash		   = udp_v4_rehash,
2600 	.get_port	   = udp_v4_get_port,
2601 	.memory_allocated  = &udp_memory_allocated,
2602 	.sysctl_mem	   = sysctl_udp_mem,
2603 	.sysctl_wmem	   = &sysctl_udp_wmem_min,
2604 	.sysctl_rmem	   = &sysctl_udp_rmem_min,
2605 	.obj_size	   = sizeof(struct udp_sock),
2606 	.h.udp_table	   = &udp_table,
2607 #ifdef CONFIG_COMPAT
2608 	.compat_setsockopt = compat_udp_setsockopt,
2609 	.compat_getsockopt = compat_udp_getsockopt,
2610 #endif
2611 	.diag_destroy	   = udp_abort,
2612 };
2613 EXPORT_SYMBOL(udp_prot);
2614 
2615 /* ------------------------------------------------------------------------ */
2616 #ifdef CONFIG_PROC_FS
2617 
udp_get_first(struct seq_file * seq,int start)2618 static struct sock *udp_get_first(struct seq_file *seq, int start)
2619 {
2620 	struct sock *sk;
2621 	struct udp_iter_state *state = seq->private;
2622 	struct net *net = seq_file_net(seq);
2623 
2624 	for (state->bucket = start; state->bucket <= state->udp_table->mask;
2625 	     ++state->bucket) {
2626 		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
2627 
2628 		if (hlist_empty(&hslot->head))
2629 			continue;
2630 
2631 		spin_lock_bh(&hslot->lock);
2632 		sk_for_each(sk, &hslot->head) {
2633 			if (!net_eq(sock_net(sk), net))
2634 				continue;
2635 			if (sk->sk_family == state->family)
2636 				goto found;
2637 		}
2638 		spin_unlock_bh(&hslot->lock);
2639 	}
2640 	sk = NULL;
2641 found:
2642 	return sk;
2643 }
2644 
udp_get_next(struct seq_file * seq,struct sock * sk)2645 static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
2646 {
2647 	struct udp_iter_state *state = seq->private;
2648 	struct net *net = seq_file_net(seq);
2649 
2650 	do {
2651 		sk = sk_next(sk);
2652 	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
2653 
2654 	if (!sk) {
2655 		if (state->bucket <= state->udp_table->mask)
2656 			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2657 		return udp_get_first(seq, state->bucket + 1);
2658 	}
2659 	return sk;
2660 }
2661 
udp_get_idx(struct seq_file * seq,loff_t pos)2662 static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2663 {
2664 	struct sock *sk = udp_get_first(seq, 0);
2665 
2666 	if (sk)
2667 		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2668 			--pos;
2669 	return pos ? NULL : sk;
2670 }
2671 
udp_seq_start(struct seq_file * seq,loff_t * pos)2672 static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2673 {
2674 	struct udp_iter_state *state = seq->private;
2675 	state->bucket = MAX_UDP_PORTS;
2676 
2677 	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2678 }
2679 
udp_seq_next(struct seq_file * seq,void * v,loff_t * pos)2680 static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2681 {
2682 	struct sock *sk;
2683 
2684 	if (v == SEQ_START_TOKEN)
2685 		sk = udp_get_idx(seq, 0);
2686 	else
2687 		sk = udp_get_next(seq, v);
2688 
2689 	++*pos;
2690 	return sk;
2691 }
2692 
udp_seq_stop(struct seq_file * seq,void * v)2693 static void udp_seq_stop(struct seq_file *seq, void *v)
2694 {
2695 	struct udp_iter_state *state = seq->private;
2696 
2697 	if (state->bucket <= state->udp_table->mask)
2698 		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2699 }
2700 
udp_seq_open(struct inode * inode,struct file * file)2701 int udp_seq_open(struct inode *inode, struct file *file)
2702 {
2703 	struct udp_seq_afinfo *afinfo = PDE_DATA(inode);
2704 	struct udp_iter_state *s;
2705 	int err;
2706 
2707 	err = seq_open_net(inode, file, &afinfo->seq_ops,
2708 			   sizeof(struct udp_iter_state));
2709 	if (err < 0)
2710 		return err;
2711 
2712 	s = ((struct seq_file *)file->private_data)->private;
2713 	s->family		= afinfo->family;
2714 	s->udp_table		= afinfo->udp_table;
2715 	return err;
2716 }
2717 EXPORT_SYMBOL(udp_seq_open);
2718 
2719 /* ------------------------------------------------------------------------ */
udp_proc_register(struct net * net,struct udp_seq_afinfo * afinfo)2720 int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2721 {
2722 	struct proc_dir_entry *p;
2723 	int rc = 0;
2724 
2725 	afinfo->seq_ops.start		= udp_seq_start;
2726 	afinfo->seq_ops.next		= udp_seq_next;
2727 	afinfo->seq_ops.stop		= udp_seq_stop;
2728 
2729 	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2730 			     afinfo->seq_fops, afinfo);
2731 	if (!p)
2732 		rc = -ENOMEM;
2733 	return rc;
2734 }
2735 EXPORT_SYMBOL(udp_proc_register);
2736 
udp_proc_unregister(struct net * net,struct udp_seq_afinfo * afinfo)2737 void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2738 {
2739 	remove_proc_entry(afinfo->name, net->proc_net);
2740 }
2741 EXPORT_SYMBOL(udp_proc_unregister);
2742 
2743 /* ------------------------------------------------------------------------ */
udp4_format_sock(struct sock * sp,struct seq_file * f,int bucket)2744 static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2745 		int bucket)
2746 {
2747 	struct inet_sock *inet = inet_sk(sp);
2748 	__be32 dest = inet->inet_daddr;
2749 	__be32 src  = inet->inet_rcv_saddr;
2750 	__u16 destp	  = ntohs(inet->inet_dport);
2751 	__u16 srcp	  = ntohs(inet->inet_sport);
2752 
2753 	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2754 		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
2755 		bucket, src, srcp, dest, destp, sp->sk_state,
2756 		sk_wmem_alloc_get(sp),
2757 		udp_rqueue_get(sp),
2758 		0, 0L, 0,
2759 		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
2760 		0, sock_i_ino(sp),
2761 		refcount_read(&sp->sk_refcnt), sp,
2762 		atomic_read(&sp->sk_drops));
2763 }
2764 
udp4_seq_show(struct seq_file * seq,void * v)2765 int udp4_seq_show(struct seq_file *seq, void *v)
2766 {
2767 	seq_setwidth(seq, 127);
2768 	if (v == SEQ_START_TOKEN)
2769 		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
2770 			   "rx_queue tr tm->when retrnsmt   uid  timeout "
2771 			   "inode ref pointer drops");
2772 	else {
2773 		struct udp_iter_state *state = seq->private;
2774 
2775 		udp4_format_sock(v, seq, state->bucket);
2776 	}
2777 	seq_pad(seq, '\n');
2778 	return 0;
2779 }
2780 
2781 static const struct file_operations udp_afinfo_seq_fops = {
2782 	.owner    = THIS_MODULE,
2783 	.open     = udp_seq_open,
2784 	.read     = seq_read,
2785 	.llseek   = seq_lseek,
2786 	.release  = seq_release_net
2787 };
2788 
2789 /* ------------------------------------------------------------------------ */
2790 static struct udp_seq_afinfo udp4_seq_afinfo = {
2791 	.name		= "udp",
2792 	.family		= AF_INET,
2793 	.udp_table	= &udp_table,
2794 	.seq_fops	= &udp_afinfo_seq_fops,
2795 	.seq_ops	= {
2796 		.show		= udp4_seq_show,
2797 	},
2798 };
2799 
udp4_proc_init_net(struct net * net)2800 static int __net_init udp4_proc_init_net(struct net *net)
2801 {
2802 	return udp_proc_register(net, &udp4_seq_afinfo);
2803 }
2804 
udp4_proc_exit_net(struct net * net)2805 static void __net_exit udp4_proc_exit_net(struct net *net)
2806 {
2807 	udp_proc_unregister(net, &udp4_seq_afinfo);
2808 }
2809 
2810 static struct pernet_operations udp4_net_ops = {
2811 	.init = udp4_proc_init_net,
2812 	.exit = udp4_proc_exit_net,
2813 };
2814 
udp4_proc_init(void)2815 int __init udp4_proc_init(void)
2816 {
2817 	return register_pernet_subsys(&udp4_net_ops);
2818 }
2819 
udp4_proc_exit(void)2820 void udp4_proc_exit(void)
2821 {
2822 	unregister_pernet_subsys(&udp4_net_ops);
2823 }
2824 #endif /* CONFIG_PROC_FS */
2825 
2826 static __initdata unsigned long uhash_entries;
set_uhash_entries(char * str)2827 static int __init set_uhash_entries(char *str)
2828 {
2829 	ssize_t ret;
2830 
2831 	if (!str)
2832 		return 0;
2833 
2834 	ret = kstrtoul(str, 0, &uhash_entries);
2835 	if (ret)
2836 		return 0;
2837 
2838 	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2839 		uhash_entries = UDP_HTABLE_SIZE_MIN;
2840 	return 1;
2841 }
2842 __setup("uhash_entries=", set_uhash_entries);
2843 
udp_table_init(struct udp_table * table,const char * name)2844 void __init udp_table_init(struct udp_table *table, const char *name)
2845 {
2846 	unsigned int i;
2847 
2848 	table->hash = alloc_large_system_hash(name,
2849 					      2 * sizeof(struct udp_hslot),
2850 					      uhash_entries,
2851 					      21, /* one slot per 2 MB */
2852 					      0,
2853 					      &table->log,
2854 					      &table->mask,
2855 					      UDP_HTABLE_SIZE_MIN,
2856 					      64 * 1024);
2857 
2858 	table->hash2 = table->hash + (table->mask + 1);
2859 	for (i = 0; i <= table->mask; i++) {
2860 		INIT_HLIST_HEAD(&table->hash[i].head);
2861 		table->hash[i].count = 0;
2862 		spin_lock_init(&table->hash[i].lock);
2863 	}
2864 	for (i = 0; i <= table->mask; i++) {
2865 		INIT_HLIST_HEAD(&table->hash2[i].head);
2866 		table->hash2[i].count = 0;
2867 		spin_lock_init(&table->hash2[i].lock);
2868 	}
2869 }
2870 
udp_flow_hashrnd(void)2871 u32 udp_flow_hashrnd(void)
2872 {
2873 	static u32 hashrnd __read_mostly;
2874 
2875 	net_get_random_once(&hashrnd, sizeof(hashrnd));
2876 
2877 	return hashrnd;
2878 }
2879 EXPORT_SYMBOL(udp_flow_hashrnd);
2880 
udp_init(void)2881 void __init udp_init(void)
2882 {
2883 	unsigned long limit;
2884 	unsigned int i;
2885 
2886 	udp_table_init(&udp_table, "UDP");
2887 	limit = nr_free_buffer_pages() / 8;
2888 	limit = max(limit, 128UL);
2889 	sysctl_udp_mem[0] = limit / 4 * 3;
2890 	sysctl_udp_mem[1] = limit;
2891 	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2892 
2893 	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2894 	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2895 
2896 	/* 16 spinlocks per cpu */
2897 	udp_busylocks_log = ilog2(nr_cpu_ids) + 4;
2898 	udp_busylocks = kmalloc(sizeof(spinlock_t) << udp_busylocks_log,
2899 				GFP_KERNEL);
2900 	if (!udp_busylocks)
2901 		panic("UDP: failed to alloc udp_busylocks\n");
2902 	for (i = 0; i < (1U << udp_busylocks_log); i++)
2903 		spin_lock_init(udp_busylocks + i);
2904 }
2905