1/*
   2 * INET		An implementation of the TCP/IP protocol suite for the LINUX
   3 *		operating system.  INET is implemented using the  BSD Socket
   4 *		interface as the means of communication with the user level.
   5 *
   6 *		The User Datagram Protocol (UDP).
   7 *
   8 * Authors:	Ross Biro
   9 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  11 *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
  12 *		Hirokazu Takahashi, <taka@valinux.co.jp>
  13 *
  14 * Fixes:
  15 *		Alan Cox	:	verify_area() calls
  16 *		Alan Cox	: 	stopped close while in use off icmp
  17 *					messages. Not a fix but a botch that
  18 *					for udp at least is 'valid'.
  19 *		Alan Cox	:	Fixed icmp handling properly
  20 *		Alan Cox	: 	Correct error for oversized datagrams
  21 *		Alan Cox	:	Tidied select() semantics.
  22 *		Alan Cox	:	udp_err() fixed properly, also now
  23 *					select and read wake correctly on errors
  24 *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
  25 *		Alan Cox	:	UDP can count its memory
  26 *		Alan Cox	:	send to an unknown connection causes
  27 *					an ECONNREFUSED off the icmp, but
  28 *					does NOT close.
  29 *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
  30 *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
  31 *					bug no longer crashes it.
  32 *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
  33 *		Alan Cox	:	Uses skb_free_datagram
  34 *		Alan Cox	:	Added get/set sockopt support.
  35 *		Alan Cox	:	Broadcasting without option set returns EACCES.
  36 *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
  37 *		Alan Cox	:	Use ip_tos and ip_ttl
  38 *		Alan Cox	:	SNMP Mibs
  39 *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
  40 *		Matt Dillon	:	UDP length checks.
  41 *		Alan Cox	:	Smarter af_inet used properly.
  42 *		Alan Cox	:	Use new kernel side addressing.
  43 *		Alan Cox	:	Incorrect return on truncated datagram receive.
  44 *	Arnt Gulbrandsen 	:	New udp_send and stuff
  45 *		Alan Cox	:	Cache last socket
  46 *		Alan Cox	:	Route cache
  47 *		Jon Peatfield	:	Minor efficiency fix to sendto().
  48 *		Mike Shaver	:	RFC1122 checks.
  49 *		Alan Cox	:	Nonblocking error fix.
  50 *	Willy Konynenberg	:	Transparent proxying support.
  51 *		Mike McLagan	:	Routing by source
  52 *		David S. Miller	:	New socket lookup architecture.
  53 *					Last socket cache retained as it
  54 *					does have a high hit rate.
  55 *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
  56 *		Andi Kleen	:	Some cleanups, cache destination entry
  57 *					for connect.
  58 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
  59 *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
  60 *					return ENOTCONN for unconnected sockets (POSIX)
  61 *		Janos Farkas	:	don't deliver multi/broadcasts to a different
  62 *					bound-to-device socket
  63 *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
  64 *					datagrams.
  65 *	Hirokazu Takahashi	:	sendfile() on UDP works now.
  66 *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
  67 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
  68 *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
  69 *					a single port at the same time.
  70 *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
  71 *	James Chapman		:	Add L2TP encapsulation type.
  72 *
  73 *
  74 *		This program is free software; you can redistribute it and/or
  75 *		modify it under the terms of the GNU General Public License
  76 *		as published by the Free Software Foundation; either version
  77 *		2 of the License, or (at your option) any later version.
  78 */
  79
  80#define pr_fmt(fmt) "UDP: " fmt
  81
  82#include <asm/uaccess.h>
  83#include <asm/ioctls.h>
  84#include <linux/bootmem.h>
  85#include <linux/highmem.h>
  86#include <linux/swap.h>
  87#include <linux/types.h>
  88#include <linux/fcntl.h>
  89#include <linux/module.h>
  90#include <linux/socket.h>
  91#include <linux/sockios.h>
  92#include <linux/igmp.h>
  93#include <linux/in.h>
  94#include <linux/errno.h>
  95#include <linux/timer.h>
  96#include <linux/mm.h>
  97#include <linux/inet.h>
  98#include <linux/netdevice.h>
  99#include <linux/slab.h>
 100#include <net/tcp_states.h>
 101#include <linux/skbuff.h>
 102#include <linux/proc_fs.h>
 103#include <linux/seq_file.h>
 104#include <net/net_namespace.h>
 105#include <net/icmp.h>
 106#include <net/inet_hashtables.h>
 107#include <net/route.h>
 108#include <net/checksum.h>
 109#include <net/xfrm.h>
 110#include <trace/events/udp.h>
 111#include <linux/static_key.h>
 112#include <trace/events/skb.h>
 113#include <net/busy_poll.h>
 114#include "udp_impl.h"
 115
 116struct udp_table udp_table __read_mostly;
 117EXPORT_SYMBOL(udp_table);
 118
 119long sysctl_udp_mem[3] __read_mostly;
 120EXPORT_SYMBOL(sysctl_udp_mem);
 121
 122int sysctl_udp_rmem_min __read_mostly;
 123EXPORT_SYMBOL(sysctl_udp_rmem_min);
 124
 125int sysctl_udp_wmem_min __read_mostly;
 126EXPORT_SYMBOL(sysctl_udp_wmem_min);
 127
 128atomic_long_t udp_memory_allocated;
 129EXPORT_SYMBOL(udp_memory_allocated);
 130
 131#define MAX_UDP_PORTS 65536
 132#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
 133
 134static int udp_lib_lport_inuse(struct net *net, __u16 num,
 135			       const struct udp_hslot *hslot,
 136			       unsigned long *bitmap,
 137			       struct sock *sk,
 138			       int (*saddr_comp)(const struct sock *sk1,
 139						 const struct sock *sk2),
 140			       unsigned int log)
 141{
 142	struct sock *sk2;
 143	struct hlist_nulls_node *node;
 144	kuid_t uid = sock_i_uid(sk);
 145
 146	sk_nulls_for_each(sk2, node, &hslot->head)
 147		if (net_eq(sock_net(sk2), net) &&
 148		    sk2 != sk &&
 149		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
 150		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 151		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 152		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 153		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
 154		      !uid_eq(uid, sock_i_uid(sk2))) &&
 155		    (*saddr_comp)(sk, sk2)) {
 156			if (bitmap)
 157				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
 158					  bitmap);
 159			else
 160				return 1;
 161		}
 162	return 0;
 163}
 164
 165/*
 166 * Note: we still hold spinlock of primary hash chain, so no other writer
 167 * can insert/delete a socket with local_port == num
 168 */
 169static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 170			       struct udp_hslot *hslot2,
 171			       struct sock *sk,
 172			       int (*saddr_comp)(const struct sock *sk1,
 173						 const struct sock *sk2))
 174{
 175	struct sock *sk2;
 176	struct hlist_nulls_node *node;
 177	kuid_t uid = sock_i_uid(sk);
 178	int res = 0;
 179
 180	spin_lock(&hslot2->lock);
 181	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
 182		if (net_eq(sock_net(sk2), net) &&
 183		    sk2 != sk &&
 184		    (udp_sk(sk2)->udp_port_hash == num) &&
 185		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 186		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 187		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 188		    (!sk2->sk_reuseport || !sk->sk_reuseport ||
 189		      !uid_eq(uid, sock_i_uid(sk2))) &&
 190		    (*saddr_comp)(sk, sk2)) {
 191			res = 1;
 192			break;
 193		}
 194	spin_unlock(&hslot2->lock);
 195	return res;
 196}
 197
 198/**
 199 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
 200 *
 201 *  @sk:          socket struct in question
 202 *  @snum:        port number to look up
 203 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
 204 *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
 205 *                   with NULL address
 206 */
 207int udp_lib_get_port(struct sock *sk, unsigned short snum,
 208		       int (*saddr_comp)(const struct sock *sk1,
 209					 const struct sock *sk2),
 210		     unsigned int hash2_nulladdr)
 211{
 212	struct udp_hslot *hslot, *hslot2;
 213	struct udp_table *udptable = sk->sk_prot->h.udp_table;
 214	int    error = 1;
 215	struct net *net = sock_net(sk);
 216
 217	if (!snum) {
 218		int low, high, remaining;
 219		unsigned int rand;
 220		unsigned short first, last;
 221		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
 222
 223		inet_get_local_port_range(net, &low, &high);
 224		remaining = (high - low) + 1;
 225
 226		rand = prandom_u32();
 227		first = (((u64)rand * remaining) >> 32) + low;
 228		/*
 229		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
 230		 */
 231		rand = (rand | 1) * (udptable->mask + 1);
 232		last = first + udptable->mask + 1;
 233		do {
 234			hslot = udp_hashslot(udptable, net, first);
 235			bitmap_zero(bitmap, PORTS_PER_CHAIN);
 236			spin_lock_bh(&hslot->lock);
 237			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
 238					    saddr_comp, udptable->log);
 239
 240			snum = first;
 241			/*
 242			 * Iterate on all possible values of snum for this hash.
 243			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
 244			 * give us randomization and full range coverage.
 245			 */
 246			do {
 247				if (low <= snum && snum <= high &&
 248				    !test_bit(snum >> udptable->log, bitmap) &&
 249				    !inet_is_reserved_local_port(snum))
 250					goto found;
 251				snum += rand;
 252			} while (snum != first);
 253			spin_unlock_bh(&hslot->lock);
 254		} while (++first != last);
 255		goto fail;
 256	} else {
 257		hslot = udp_hashslot(udptable, net, snum);
 258		spin_lock_bh(&hslot->lock);
 259		if (hslot->count > 10) {
 260			int exist;
 261			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
 262
 263			slot2          &= udptable->mask;
 264			hash2_nulladdr &= udptable->mask;
 265
 266			hslot2 = udp_hashslot2(udptable, slot2);
 267			if (hslot->count < hslot2->count)
 268				goto scan_primary_hash;
 269
 270			exist = udp_lib_lport_inuse2(net, snum, hslot2,
 271						     sk, saddr_comp);
 272			if (!exist && (hash2_nulladdr != slot2)) {
 273				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
 274				exist = udp_lib_lport_inuse2(net, snum, hslot2,
 275							     sk, saddr_comp);
 276			}
 277			if (exist)
 278				goto fail_unlock;
 279			else
 280				goto found;
 281		}
 282scan_primary_hash:
 283		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
 284					saddr_comp, 0))
 285			goto fail_unlock;
 286	}
 287found:
 288	inet_sk(sk)->inet_num = snum;
 289	udp_sk(sk)->udp_port_hash = snum;
 290	udp_sk(sk)->udp_portaddr_hash ^= snum;
 291	if (sk_unhashed(sk)) {
 292		sk_nulls_add_node_rcu(sk, &hslot->head);
 293		hslot->count++;
 294		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 295
 296		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
 297		spin_lock(&hslot2->lock);
 298		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
 299					 &hslot2->head);
 300		hslot2->count++;
 301		spin_unlock(&hslot2->lock);
 302	}
 303	error = 0;
 304fail_unlock:
 305	spin_unlock_bh(&hslot->lock);
 306fail:
 307	return error;
 308}
 309EXPORT_SYMBOL(udp_lib_get_port);
 310
 311static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
 312{
 313	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
 314
 315	return 	(!ipv6_only_sock(sk2)  &&
 316		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
 317		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
 318}
 319
 320static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
 321				       unsigned int port)
 322{
 323	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 324}
 325
 326int udp_v4_get_port(struct sock *sk, unsigned short snum)
 327{
 328	unsigned int hash2_nulladdr =
 329		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
 330	unsigned int hash2_partial =
 331		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
 332
 333	/* precompute partial secondary hash */
 334	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
 335	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
 336}
 337
 338static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 339			 unsigned short hnum,
 340			 __be16 sport, __be32 daddr, __be16 dport, int dif)
 341{
 342	int score = -1;
 343
 344	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
 345			!ipv6_only_sock(sk)) {
 346		struct inet_sock *inet = inet_sk(sk);
 347
 348		score = (sk->sk_family == PF_INET ? 2 : 1);
 349		if (inet->inet_rcv_saddr) {
 350			if (inet->inet_rcv_saddr != daddr)
 351				return -1;
 352			score += 4;
 353		}
 354		if (inet->inet_daddr) {
 355			if (inet->inet_daddr != saddr)
 356				return -1;
 357			score += 4;
 358		}
 359		if (inet->inet_dport) {
 360			if (inet->inet_dport != sport)
 361				return -1;
 362			score += 4;
 363		}
 364		if (sk->sk_bound_dev_if) {
 365			if (sk->sk_bound_dev_if != dif)
 366				return -1;
 367			score += 4;
 368		}
 369	}
 370	return score;
 371}
 372
 373/*
 374 * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
 375 */
 
 376static inline int compute_score2(struct sock *sk, struct net *net,
 377				 __be32 saddr, __be16 sport,
 378				 __be32 daddr, unsigned int hnum, int dif)
 379{
 380	int score = -1;
 381
 382	if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
 383		struct inet_sock *inet = inet_sk(sk);
 384
 385		if (inet->inet_rcv_saddr != daddr)
 386			return -1;
 387		if (inet->inet_num != hnum)
 388			return -1;
 389
 390		score = (sk->sk_family == PF_INET ? 2 : 1);
 391		if (inet->inet_daddr) {
 392			if (inet->inet_daddr != saddr)
 393				return -1;
 394			score += 4;
 395		}
 396		if (inet->inet_dport) {
 397			if (inet->inet_dport != sport)
 398				return -1;
 399			score += 4;
 400		}
 401		if (sk->sk_bound_dev_if) {
 402			if (sk->sk_bound_dev_if != dif)
 403				return -1;
 404			score += 4;
 405		}
 406	}
 407	return score;
 408}
 409
 410static unsigned int udp_ehashfn(struct net *net, const __be32 laddr,
 411				 const __u16 lport, const __be32 faddr,
 412				 const __be16 fport)
 413{
 414	static u32 udp_ehash_secret __read_mostly;
 415
 416	net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
 417
 418	return __inet_ehashfn(laddr, lport, faddr, fport,
 419			      udp_ehash_secret + net_hash_mix(net));
 420}
 421
 422
 423/* called with read_rcu_lock() */
 424static struct sock *udp4_lib_lookup2(struct net *net,
 425		__be32 saddr, __be16 sport,
 426		__be32 daddr, unsigned int hnum, int dif,
 427		struct udp_hslot *hslot2, unsigned int slot2)
 428{
 429	struct sock *sk, *result;
 430	struct hlist_nulls_node *node;
 431	int score, badness, matches = 0, reuseport = 0;
 432	u32 hash = 0;
 433
 434begin:
 435	result = NULL;
 436	badness = 0;
 437	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
 438		score = compute_score2(sk, net, saddr, sport,
 439				      daddr, hnum, dif);
 440		if (score > badness) {
 441			result = sk;
 442			badness = score;
 443			reuseport = sk->sk_reuseport;
 444			if (reuseport) {
 445				hash = udp_ehashfn(net, daddr, hnum,
 446						   saddr, sport);
 447				matches = 1;
 448			}
 449		} else if (score == badness && reuseport) {
 450			matches++;
 451			if (((u64)hash * matches) >> 32 == 0)
 452				result = sk;
 453			hash = next_pseudo_random32(hash);
 454		}
 455	}
 456	/*
 457	 * if the nulls value we got at the end of this lookup is
 458	 * not the expected one, we must restart lookup.
 459	 * We probably met an item that was moved to another chain.
 460	 */
 461	if (get_nulls_value(node) != slot2)
 462		goto begin;
 
 463	if (result) {
 
 464		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 465			result = NULL;
 466		else if (unlikely(compute_score2(result, net, saddr, sport,
 467				  daddr, hnum, dif) < badness)) {
 468			sock_put(result);
 469			goto begin;
 470		}
 471	}
 472	return result;
 473}
 474
 475/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 476 * harder than this. -DaveM
 477 */
 478struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 479		__be16 sport, __be32 daddr, __be16 dport,
 480		int dif, struct udp_table *udptable)
 481{
 482	struct sock *sk, *result;
 483	struct hlist_nulls_node *node;
 484	unsigned short hnum = ntohs(dport);
 485	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 486	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
 487	int score, badness, matches = 0, reuseport = 0;
 488	u32 hash = 0;
 489
 490	rcu_read_lock();
 491	if (hslot->count > 10) {
 492		hash2 = udp4_portaddr_hash(net, daddr, hnum);
 493		slot2 = hash2 & udptable->mask;
 494		hslot2 = &udptable->hash2[slot2];
 495		if (hslot->count < hslot2->count)
 496			goto begin;
 497
 498		result = udp4_lib_lookup2(net, saddr, sport,
 499					  daddr, hnum, dif,
 500					  hslot2, slot2);
 501		if (!result) {
 502			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
 503			slot2 = hash2 & udptable->mask;
 504			hslot2 = &udptable->hash2[slot2];
 505			if (hslot->count < hslot2->count)
 506				goto begin;
 507
 508			result = udp4_lib_lookup2(net, saddr, sport,
 509						  htonl(INADDR_ANY), hnum, dif,
 510						  hslot2, slot2);
 511		}
 512		rcu_read_unlock();
 513		return result;
 514	}
 515begin:
 516	result = NULL;
 517	badness = 0;
 518	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
 519		score = compute_score(sk, net, saddr, hnum, sport,
 520				      daddr, dport, dif);
 521		if (score > badness) {
 522			result = sk;
 523			badness = score;
 524			reuseport = sk->sk_reuseport;
 525			if (reuseport) {
 526				hash = udp_ehashfn(net, daddr, hnum,
 527						   saddr, sport);
 528				matches = 1;
 529			}
 530		} else if (score == badness && reuseport) {
 531			matches++;
 532			if (((u64)hash * matches) >> 32 == 0)
 533				result = sk;
 534			hash = next_pseudo_random32(hash);
 535		}
 536	}
 537	/*
 538	 * if the nulls value we got at the end of this lookup is
 539	 * not the expected one, we must restart lookup.
 540	 * We probably met an item that was moved to another chain.
 541	 */
 542	if (get_nulls_value(node) != slot)
 543		goto begin;
 544
 545	if (result) {
 546		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 547			result = NULL;
 548		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
 549				  daddr, dport, dif) < badness)) {
 550			sock_put(result);
 551			goto begin;
 552		}
 553	}
 554	rcu_read_unlock();
 555	return result;
 556}
 557EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
 558
 559static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 560						 __be16 sport, __be16 dport,
 561						 struct udp_table *udptable)
 562{
 
 563	const struct iphdr *iph = ip_hdr(skb);
 564
 565	return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
 566				 iph->daddr, dport, inet_iif(skb),
 567				 udptable);
 
 
 
 568}
 569
 570struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 571			     __be32 daddr, __be16 dport, int dif)
 572{
 573	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
 574}
 575EXPORT_SYMBOL_GPL(udp4_lib_lookup);
 576
 577static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
 578				       __be16 loc_port, __be32 loc_addr,
 579				       __be16 rmt_port, __be32 rmt_addr,
 580				       int dif, unsigned short hnum)
 581{
 582	struct inet_sock *inet = inet_sk(sk);
 583
 584	if (!net_eq(sock_net(sk), net) ||
 585	    udp_sk(sk)->udp_port_hash != hnum ||
 586	    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
 587	    (inet->inet_dport != rmt_port && inet->inet_dport) ||
 588	    (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
 589	    ipv6_only_sock(sk) ||
 590	    (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif))
 591		return false;
 592	if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif))
 593		return false;
 594	return true;
 595}
 596
 597static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
 598					     __be16 loc_port, __be32 loc_addr,
 599					     __be16 rmt_port, __be32 rmt_addr,
 600					     int dif)
 601{
 602	struct hlist_nulls_node *node;
 603	struct sock *s = sk;
 604	unsigned short hnum = ntohs(loc_port);
 605
 606	sk_nulls_for_each_from(s, node) {
 607		if (__udp_is_mcast_sock(net, s,
 608					loc_port, loc_addr,
 609					rmt_port, rmt_addr,
 610					dif, hnum))
 611			goto found;
 
 
 
 
 
 
 
 
 
 612	}
 613	s = NULL;
 614found:
 615	return s;
 616}
 617
 618/*
 619 * This routine is called by the ICMP module when it gets some
 620 * sort of error condition.  If err < 0 then the socket should
 621 * be closed and the error returned to the user.  If err > 0
 622 * it's just the icmp type << 8 | icmp code.
 623 * Header points to the ip header of the error packet. We move
 624 * on past this. Then (as it used to claim before adjustment)
 625 * header points to the first 8 bytes of the udp header.  We need
 626 * to find the appropriate port.
 627 */
 628
 629void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 630{
 631	struct inet_sock *inet;
 632	const struct iphdr *iph = (const struct iphdr *)skb->data;
 633	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
 634	const int type = icmp_hdr(skb)->type;
 635	const int code = icmp_hdr(skb)->code;
 636	struct sock *sk;
 637	int harderr;
 638	int err;
 639	struct net *net = dev_net(skb->dev);
 640
 641	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
 642			iph->saddr, uh->source, skb->dev->ifindex, udptable);
 643	if (sk == NULL) {
 644		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 645		return;	/* No socket for error */
 646	}
 647
 648	err = 0;
 649	harderr = 0;
 650	inet = inet_sk(sk);
 651
 652	switch (type) {
 653	default:
 654	case ICMP_TIME_EXCEEDED:
 655		err = EHOSTUNREACH;
 656		break;
 657	case ICMP_SOURCE_QUENCH:
 658		goto out;
 659	case ICMP_PARAMETERPROB:
 660		err = EPROTO;
 661		harderr = 1;
 662		break;
 663	case ICMP_DEST_UNREACH:
 664		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 665			ipv4_sk_update_pmtu(skb, sk, info);
 666			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
 667				err = EMSGSIZE;
 668				harderr = 1;
 669				break;
 670			}
 671			goto out;
 672		}
 673		err = EHOSTUNREACH;
 674		if (code <= NR_ICMP_UNREACH) {
 675			harderr = icmp_err_convert[code].fatal;
 676			err = icmp_err_convert[code].errno;
 677		}
 678		break;
 679	case ICMP_REDIRECT:
 680		ipv4_sk_redirect(skb, sk);
 681		goto out;
 682	}
 683
 684	/*
 685	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
 686	 *	4.1.3.3.
 687	 */
 688	if (!inet->recverr) {
 689		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 690			goto out;
 691	} else
 692		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
 693
 694	sk->sk_err = err;
 695	sk->sk_error_report(sk);
 696out:
 697	sock_put(sk);
 698}
 699
 700void udp_err(struct sk_buff *skb, u32 info)
 701{
 702	__udp4_lib_err(skb, info, &udp_table);
 703}
 704
 705/*
 706 * Throw away all pending data and cancel the corking. Socket is locked.
 707 */
 708void udp_flush_pending_frames(struct sock *sk)
 709{
 710	struct udp_sock *up = udp_sk(sk);
 711
 712	if (up->pending) {
 713		up->len = 0;
 714		up->pending = 0;
 715		ip_flush_pending_frames(sk);
 716	}
 717}
 718EXPORT_SYMBOL(udp_flush_pending_frames);
 719
 720/**
 721 * 	udp4_hwcsum  -  handle outgoing HW checksumming
 722 * 	@skb: 	sk_buff containing the filled-in UDP header
 723 * 	        (checksum field must be zeroed out)
 724 *	@src:	source IP address
 725 *	@dst:	destination IP address
 726 */
 727void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
 728{
 729	struct udphdr *uh = udp_hdr(skb);
 730	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
 731	int offset = skb_transport_offset(skb);
 732	int len = skb->len - offset;
 733	int hlen = len;
 734	__wsum csum = 0;
 735
 736	if (!frags) {
 737		/*
 738		 * Only one fragment on the socket.
 739		 */
 740		skb->csum_start = skb_transport_header(skb) - skb->head;
 741		skb->csum_offset = offsetof(struct udphdr, check);
 742		uh->check = ~csum_tcpudp_magic(src, dst, len,
 743					       IPPROTO_UDP, 0);
 744	} else {
 745		/*
 746		 * HW-checksum won't work as there are two or more
 747		 * fragments on the socket so that all csums of sk_buffs
 748		 * should be together
 749		 */
 750		do {
 751			csum = csum_add(csum, frags->csum);
 752			hlen -= frags->len;
 753		} while ((frags = frags->next));
 754
 755		csum = skb_checksum(skb, offset, hlen, csum);
 756		skb->ip_summed = CHECKSUM_NONE;
 757
 758		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
 759		if (uh->check == 0)
 760			uh->check = CSUM_MANGLED_0;
 761	}
 762}
 763EXPORT_SYMBOL_GPL(udp4_hwcsum);
 764
 765static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 766{
 767	struct sock *sk = skb->sk;
 768	struct inet_sock *inet = inet_sk(sk);
 769	struct udphdr *uh;
 770	int err = 0;
 771	int is_udplite = IS_UDPLITE(sk);
 772	int offset = skb_transport_offset(skb);
 773	int len = skb->len - offset;
 774	__wsum csum = 0;
 775
 776	/*
 777	 * Create a UDP header
 778	 */
 779	uh = udp_hdr(skb);
 780	uh->source = inet->inet_sport;
 781	uh->dest = fl4->fl4_dport;
 782	uh->len = htons(len);
 783	uh->check = 0;
 784
 785	if (is_udplite)  				 /*     UDP-Lite      */
 786		csum = udplite_csum(skb);
 787
 788	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */
 789
 790		skb->ip_summed = CHECKSUM_NONE;
 791		goto send;
 792
 793	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 794
 795		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
 796		goto send;
 797
 798	} else
 799		csum = udp_csum(skb);
 800
 801	/* add protocol-dependent pseudo-header */
 802	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
 803				      sk->sk_protocol, csum);
 804	if (uh->check == 0)
 805		uh->check = CSUM_MANGLED_0;
 806
 807send:
 808	err = ip_send_skb(sock_net(sk), skb);
 809	if (err) {
 810		if (err == -ENOBUFS && !inet->recverr) {
 811			UDP_INC_STATS_USER(sock_net(sk),
 812					   UDP_MIB_SNDBUFERRORS, is_udplite);
 813			err = 0;
 814		}
 815	} else
 816		UDP_INC_STATS_USER(sock_net(sk),
 817				   UDP_MIB_OUTDATAGRAMS, is_udplite);
 818	return err;
 819}
 820
 821/*
 822 * Push out all pending data as one UDP datagram. Socket is locked.
 823 */
 824int udp_push_pending_frames(struct sock *sk)
 825{
 826	struct udp_sock  *up = udp_sk(sk);
 827	struct inet_sock *inet = inet_sk(sk);
 828	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
 829	struct sk_buff *skb;
 830	int err = 0;
 831
 832	skb = ip_finish_skb(sk, fl4);
 833	if (!skb)
 834		goto out;
 835
 836	err = udp_send_skb(skb, fl4);
 837
 838out:
 839	up->len = 0;
 840	up->pending = 0;
 841	return err;
 842}
 843EXPORT_SYMBOL(udp_push_pending_frames);
 844
 845int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 846		size_t len)
 847{
 848	struct inet_sock *inet = inet_sk(sk);
 849	struct udp_sock *up = udp_sk(sk);
 850	struct flowi4 fl4_stack;
 851	struct flowi4 *fl4;
 852	int ulen = len;
 853	struct ipcm_cookie ipc;
 854	struct rtable *rt = NULL;
 855	int free = 0;
 856	int connected = 0;
 857	__be32 daddr, faddr, saddr;
 858	__be16 dport;
 859	u8  tos;
 860	int err, is_udplite = IS_UDPLITE(sk);
 861	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
 862	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 863	struct sk_buff *skb;
 864	struct ip_options_data opt_copy;
 865
 866	if (len > 0xFFFF)
 867		return -EMSGSIZE;
 868
 869	/*
 870	 *	Check the flags.
 871	 */
 872
 873	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
 874		return -EOPNOTSUPP;
 875
 876	ipc.opt = NULL;
 877	ipc.tx_flags = 0;
 878	ipc.ttl = 0;
 879	ipc.tos = -1;
 880
 881	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
 882
 883	fl4 = &inet->cork.fl.u.ip4;
 884	if (up->pending) {
 885		/*
 886		 * There are pending frames.
 887		 * The socket lock must be held while it's corked.
 888		 */
 889		lock_sock(sk);
 890		if (likely(up->pending)) {
 891			if (unlikely(up->pending != AF_INET)) {
 892				release_sock(sk);
 893				return -EINVAL;
 894			}
 895			goto do_append_data;
 896		}
 897		release_sock(sk);
 898	}
 899	ulen += sizeof(struct udphdr);
 900
 901	/*
 902	 *	Get and verify the address.
 903	 */
 904	if (msg->msg_name) {
 905		DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
 906		if (msg->msg_namelen < sizeof(*usin))
 907			return -EINVAL;
 908		if (usin->sin_family != AF_INET) {
 909			if (usin->sin_family != AF_UNSPEC)
 910				return -EAFNOSUPPORT;
 911		}
 912
 913		daddr = usin->sin_addr.s_addr;
 914		dport = usin->sin_port;
 915		if (dport == 0)
 916			return -EINVAL;
 917	} else {
 918		if (sk->sk_state != TCP_ESTABLISHED)
 919			return -EDESTADDRREQ;
 920		daddr = inet->inet_daddr;
 921		dport = inet->inet_dport;
 922		/* Open fast path for connected socket.
 923		   Route will not be used, if at least one option is set.
 924		 */
 925		connected = 1;
 926	}
 927	ipc.addr = inet->inet_saddr;
 928
 929	ipc.oif = sk->sk_bound_dev_if;
 930
 931	sock_tx_timestamp(sk, &ipc.tx_flags);
 932
 933	if (msg->msg_controllen) {
 934		err = ip_cmsg_send(sock_net(sk), msg, &ipc,
 935				   sk->sk_family == AF_INET6);
 936		if (err)
 937			return err;
 938		if (ipc.opt)
 939			free = 1;
 940		connected = 0;
 941	}
 942	if (!ipc.opt) {
 943		struct ip_options_rcu *inet_opt;
 944
 945		rcu_read_lock();
 946		inet_opt = rcu_dereference(inet->inet_opt);
 947		if (inet_opt) {
 948			memcpy(&opt_copy, inet_opt,
 949			       sizeof(*inet_opt) + inet_opt->opt.optlen);
 950			ipc.opt = &opt_copy.opt;
 951		}
 952		rcu_read_unlock();
 953	}
 954
 955	saddr = ipc.addr;
 956	ipc.addr = faddr = daddr;
 957
 958	if (ipc.opt && ipc.opt->opt.srr) {
 959		if (!daddr)
 960			return -EINVAL;
 961		faddr = ipc.opt->opt.faddr;
 962		connected = 0;
 963	}
 964	tos = get_rttos(&ipc, inet);
 965	if (sock_flag(sk, SOCK_LOCALROUTE) ||
 966	    (msg->msg_flags & MSG_DONTROUTE) ||
 967	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
 968		tos |= RTO_ONLINK;
 969		connected = 0;
 970	}
 971
 972	if (ipv4_is_multicast(daddr)) {
 973		if (!ipc.oif)
 974			ipc.oif = inet->mc_index;
 975		if (!saddr)
 976			saddr = inet->mc_addr;
 977		connected = 0;
 978	} else if (!ipc.oif)
 979		ipc.oif = inet->uc_index;
 980
 981	if (connected)
 982		rt = (struct rtable *)sk_dst_check(sk, 0);
 983
 984	if (rt == NULL) {
 985		struct net *net = sock_net(sk);
 986
 987		fl4 = &fl4_stack;
 988		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
 989				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
 990				   inet_sk_flowi_flags(sk),
 991				   faddr, saddr, dport, inet->inet_sport);
 992
 993		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 994		rt = ip_route_output_flow(net, fl4, sk);
 995		if (IS_ERR(rt)) {
 996			err = PTR_ERR(rt);
 997			rt = NULL;
 998			if (err == -ENETUNREACH)
 999				IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
1000			goto out;
1001		}
1002
1003		err = -EACCES;
1004		if ((rt->rt_flags & RTCF_BROADCAST) &&
1005		    !sock_flag(sk, SOCK_BROADCAST))
1006			goto out;
1007		if (connected)
1008			sk_dst_set(sk, dst_clone(&rt->dst));
1009	}
1010
1011	if (msg->msg_flags&MSG_CONFIRM)
1012		goto do_confirm;
1013back_from_confirm:
1014
1015	saddr = fl4->saddr;
1016	if (!ipc.addr)
1017		daddr = ipc.addr = fl4->daddr;
1018
1019	/* Lockless fast path for the non-corking case. */
1020	if (!corkreq) {
1021		skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
1022				  sizeof(struct udphdr), &ipc, &rt,
1023				  msg->msg_flags);
1024		err = PTR_ERR(skb);
1025		if (!IS_ERR_OR_NULL(skb))
1026			err = udp_send_skb(skb, fl4);
1027		goto out;
1028	}
1029
1030	lock_sock(sk);
1031	if (unlikely(up->pending)) {
1032		/* The socket is already corked while preparing it. */
1033		/* ... which is an evident application bug. --ANK */
1034		release_sock(sk);
1035
1036		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("cork app bug 2\n"));
1037		err = -EINVAL;
1038		goto out;
1039	}
1040	/*
1041	 *	Now cork the socket to pend data.
1042	 */
1043	fl4 = &inet->cork.fl.u.ip4;
1044	fl4->daddr = daddr;
1045	fl4->saddr = saddr;
1046	fl4->fl4_dport = dport;
1047	fl4->fl4_sport = inet->inet_sport;
1048	up->pending = AF_INET;
1049
1050do_append_data:
1051	up->len += ulen;
1052	err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
1053			     sizeof(struct udphdr), &ipc, &rt,
1054			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1055	if (err)
1056		udp_flush_pending_frames(sk);
1057	else if (!corkreq)
1058		err = udp_push_pending_frames(sk);
1059	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1060		up->pending = 0;
1061	release_sock(sk);
1062
1063out:
1064	ip_rt_put(rt);
1065	if (free)
1066		kfree(ipc.opt);
1067	if (!err)
1068		return len;
1069	/*
1070	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1071	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1072	 * we don't have a good statistic (IpOutDiscards but it can be too many
1073	 * things).  We could add another new stat but at least for now that
1074	 * seems like overkill.
1075	 */
1076	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1077		UDP_INC_STATS_USER(sock_net(sk),
1078				UDP_MIB_SNDBUFERRORS, is_udplite);
1079	}
1080	return err;
1081
1082do_confirm:
1083	dst_confirm(&rt->dst);
1084	if (!(msg->msg_flags&MSG_PROBE) || len)
1085		goto back_from_confirm;
1086	err = 0;
1087	goto out;
1088}
1089EXPORT_SYMBOL(udp_sendmsg);
1090
1091int udp_sendpage(struct sock *sk, struct page *page, int offset,
1092		 size_t size, int flags)
1093{
1094	struct inet_sock *inet = inet_sk(sk);
1095	struct udp_sock *up = udp_sk(sk);
1096	int ret;
1097
1098	if (flags & MSG_SENDPAGE_NOTLAST)
1099		flags |= MSG_MORE;
1100
1101	if (!up->pending) {
1102		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
1103
1104		/* Call udp_sendmsg to specify destination address which
1105		 * sendpage interface can't pass.
1106		 * This will succeed only when the socket is connected.
1107		 */
1108		ret = udp_sendmsg(NULL, sk, &msg, 0);
1109		if (ret < 0)
1110			return ret;
1111	}
1112
1113	lock_sock(sk);
1114
1115	if (unlikely(!up->pending)) {
1116		release_sock(sk);
1117
1118		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("udp cork app bug 3\n"));
1119		return -EINVAL;
1120	}
1121
1122	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1123			     page, offset, size, flags);
1124	if (ret == -EOPNOTSUPP) {
1125		release_sock(sk);
1126		return sock_no_sendpage(sk->sk_socket, page, offset,
1127					size, flags);
1128	}
1129	if (ret < 0) {
1130		udp_flush_pending_frames(sk);
1131		goto out;
1132	}
1133
1134	up->len += size;
1135	if (!(up->corkflag || (flags&MSG_MORE)))
1136		ret = udp_push_pending_frames(sk);
1137	if (!ret)
1138		ret = size;
1139out:
1140	release_sock(sk);
1141	return ret;
1142}
1143
1144
1145/**
1146 *	first_packet_length	- return length of first packet in receive queue
1147 *	@sk: socket
1148 *
1149 *	Drops all bad checksum frames, until a valid one is found.
1150 *	Returns the length of found skb, or 0 if none is found.
1151 */
1152static unsigned int first_packet_length(struct sock *sk)
1153{
1154	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
1155	struct sk_buff *skb;
1156	unsigned int res;
1157
1158	__skb_queue_head_init(&list_kill);
1159
1160	spin_lock_bh(&rcvq->lock);
1161	while ((skb = skb_peek(rcvq)) != NULL &&
1162		udp_lib_checksum_complete(skb)) {
1163		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS,
1164				 IS_UDPLITE(sk));
1165		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1166				 IS_UDPLITE(sk));
1167		atomic_inc(&sk->sk_drops);
1168		__skb_unlink(skb, rcvq);
1169		__skb_queue_tail(&list_kill, skb);
1170	}
1171	res = skb ? skb->len : 0;
1172	spin_unlock_bh(&rcvq->lock);
1173
1174	if (!skb_queue_empty(&list_kill)) {
1175		bool slow = lock_sock_fast(sk);
1176
1177		__skb_queue_purge(&list_kill);
1178		sk_mem_reclaim_partial(sk);
1179		unlock_sock_fast(sk, slow);
1180	}
1181	return res;
1182}
1183
1184/*
1185 *	IOCTL requests applicable to the UDP protocol
1186 */
1187
1188int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1189{
1190	switch (cmd) {
1191	case SIOCOUTQ:
1192	{
1193		int amount = sk_wmem_alloc_get(sk);
1194
1195		return put_user(amount, (int __user *)arg);
1196	}
1197
1198	case SIOCINQ:
1199	{
1200		unsigned int amount = first_packet_length(sk);
1201
1202		if (amount)
1203			/*
1204			 * We will only return the amount
1205			 * of this packet since that is all
1206			 * that will be read.
1207			 */
1208			amount -= sizeof(struct udphdr);
1209
1210		return put_user(amount, (int __user *)arg);
1211	}
1212
1213	default:
1214		return -ENOIOCTLCMD;
1215	}
1216
1217	return 0;
1218}
1219EXPORT_SYMBOL(udp_ioctl);
1220
1221/*
1222 * 	This should be easy, if there is something there we
1223 * 	return it, otherwise we block.
1224 */
1225
1226int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1227		size_t len, int noblock, int flags, int *addr_len)
1228{
1229	struct inet_sock *inet = inet_sk(sk);
1230	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
1231	struct sk_buff *skb;
1232	unsigned int ulen, copied;
1233	int peeked, off = 0;
1234	int err;
1235	int is_udplite = IS_UDPLITE(sk);
1236	bool slow;
1237
 
 
 
 
 
 
1238	if (flags & MSG_ERRQUEUE)
1239		return ip_recv_error(sk, msg, len, addr_len);
1240
1241try_again:
1242	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1243				  &peeked, &off, &err);
1244	if (!skb)
1245		goto out;
1246
1247	ulen = skb->len - sizeof(struct udphdr);
1248	copied = len;
1249	if (copied > ulen)
1250		copied = ulen;
1251	else if (copied < ulen)
1252		msg->msg_flags |= MSG_TRUNC;
1253
1254	/*
1255	 * If checksum is needed at all, try to do it while copying the
1256	 * data.  If the data is truncated, or if we only want a partial
1257	 * coverage checksum (UDP-Lite), do it before the copy.
1258	 */
1259
1260	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1261		if (udp_lib_checksum_complete(skb))
1262			goto csum_copy_err;
1263	}
1264
1265	if (skb_csum_unnecessary(skb))
1266		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1267					      msg->msg_iov, copied);
1268	else {
1269		err = skb_copy_and_csum_datagram_iovec(skb,
1270						       sizeof(struct udphdr),
1271						       msg->msg_iov);
1272
1273		if (err == -EINVAL)
1274			goto csum_copy_err;
1275	}
1276
1277	if (unlikely(err)) {
1278		trace_kfree_skb(skb, udp_recvmsg);
1279		if (!peeked) {
1280			atomic_inc(&sk->sk_drops);
1281			UDP_INC_STATS_USER(sock_net(sk),
1282					   UDP_MIB_INERRORS, is_udplite);
1283		}
1284		goto out_free;
1285	}
1286
1287	if (!peeked)
1288		UDP_INC_STATS_USER(sock_net(sk),
1289				UDP_MIB_INDATAGRAMS, is_udplite);
1290
1291	sock_recv_ts_and_drops(msg, sk, skb);
1292
1293	/* Copy the address. */
1294	if (sin) {
1295		sin->sin_family = AF_INET;
1296		sin->sin_port = udp_hdr(skb)->source;
1297		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1298		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
1299		*addr_len = sizeof(*sin);
1300	}
1301	if (inet->cmsg_flags)
1302		ip_cmsg_recv(msg, skb);
1303
1304	err = copied;
1305	if (flags & MSG_TRUNC)
1306		err = ulen;
1307
1308out_free:
1309	skb_free_datagram_locked(sk, skb);
1310out:
1311	return err;
1312
1313csum_copy_err:
1314	slow = lock_sock_fast(sk);
1315	if (!skb_kill_datagram(sk, skb, flags)) {
1316		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1317		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1318	}
1319	unlock_sock_fast(sk, slow);
1320
1321	if (noblock)
1322		return -EAGAIN;
1323
1324	/* starting over for a new packet */
1325	msg->msg_flags &= ~MSG_TRUNC;
1326	goto try_again;
1327}
1328
1329
1330int udp_disconnect(struct sock *sk, int flags)
1331{
1332	struct inet_sock *inet = inet_sk(sk);
1333	/*
1334	 *	1003.1g - break association.
1335	 */
1336
1337	sk->sk_state = TCP_CLOSE;
1338	inet->inet_daddr = 0;
1339	inet->inet_dport = 0;
1340	sock_rps_reset_rxhash(sk);
1341	sk->sk_bound_dev_if = 0;
1342	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1343		inet_reset_saddr(sk);
1344
1345	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1346		sk->sk_prot->unhash(sk);
1347		inet->inet_sport = 0;
1348	}
1349	sk_dst_reset(sk);
1350	return 0;
1351}
1352EXPORT_SYMBOL(udp_disconnect);
1353
1354void udp_lib_unhash(struct sock *sk)
1355{
1356	if (sk_hashed(sk)) {
1357		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1358		struct udp_hslot *hslot, *hslot2;
1359
1360		hslot  = udp_hashslot(udptable, sock_net(sk),
1361				      udp_sk(sk)->udp_port_hash);
1362		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1363
1364		spin_lock_bh(&hslot->lock);
1365		if (sk_nulls_del_node_init_rcu(sk)) {
1366			hslot->count--;
1367			inet_sk(sk)->inet_num = 0;
1368			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1369
1370			spin_lock(&hslot2->lock);
1371			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1372			hslot2->count--;
1373			spin_unlock(&hslot2->lock);
1374		}
1375		spin_unlock_bh(&hslot->lock);
1376	}
1377}
1378EXPORT_SYMBOL(udp_lib_unhash);
1379
1380/*
1381 * inet_rcv_saddr was changed, we must rehash secondary hash
1382 */
1383void udp_lib_rehash(struct sock *sk, u16 newhash)
1384{
1385	if (sk_hashed(sk)) {
1386		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1387		struct udp_hslot *hslot, *hslot2, *nhslot2;
1388
1389		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1390		nhslot2 = udp_hashslot2(udptable, newhash);
1391		udp_sk(sk)->udp_portaddr_hash = newhash;
1392		if (hslot2 != nhslot2) {
1393			hslot = udp_hashslot(udptable, sock_net(sk),
1394					     udp_sk(sk)->udp_port_hash);
1395			/* we must lock primary chain too */
1396			spin_lock_bh(&hslot->lock);
1397
1398			spin_lock(&hslot2->lock);
1399			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1400			hslot2->count--;
1401			spin_unlock(&hslot2->lock);
1402
1403			spin_lock(&nhslot2->lock);
1404			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1405						 &nhslot2->head);
1406			nhslot2->count++;
1407			spin_unlock(&nhslot2->lock);
1408
1409			spin_unlock_bh(&hslot->lock);
1410		}
1411	}
1412}
1413EXPORT_SYMBOL(udp_lib_rehash);
1414
1415static void udp_v4_rehash(struct sock *sk)
1416{
1417	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1418					  inet_sk(sk)->inet_rcv_saddr,
1419					  inet_sk(sk)->inet_num);
1420	udp_lib_rehash(sk, new_hash);
1421}
1422
1423static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1424{
1425	int rc;
1426
1427	if (inet_sk(sk)->inet_daddr) {
1428		sock_rps_save_rxhash(sk, skb);
1429		sk_mark_napi_id(sk, skb);
1430	}
1431
1432	rc = sock_queue_rcv_skb(sk, skb);
1433	if (rc < 0) {
1434		int is_udplite = IS_UDPLITE(sk);
1435
1436		/* Note that an ENOMEM error is charged twice */
1437		if (rc == -ENOMEM)
1438			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1439					 is_udplite);
1440		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1441		kfree_skb(skb);
1442		trace_udp_fail_queue_rcv_skb(rc, sk);
1443		return -1;
1444	}
1445
1446	return 0;
1447
1448}
1449
1450static struct static_key udp_encap_needed __read_mostly;
1451void udp_encap_enable(void)
1452{
1453	if (!static_key_enabled(&udp_encap_needed))
1454		static_key_slow_inc(&udp_encap_needed);
1455}
1456EXPORT_SYMBOL(udp_encap_enable);
1457
1458/* returns:
1459 *  -1: error
1460 *   0: success
1461 *  >0: "udp encap" protocol resubmission
1462 *
1463 * Note that in the success and error cases, the skb is assumed to
1464 * have either been requeued or freed.
1465 */
1466int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1467{
1468	struct udp_sock *up = udp_sk(sk);
1469	int rc;
1470	int is_udplite = IS_UDPLITE(sk);
1471
1472	/*
1473	 *	Charge it to the socket, dropping if the queue is full.
1474	 */
1475	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
1476		goto drop;
1477	nf_reset(skb);
1478
1479	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1480		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
1481
1482		/*
1483		 * This is an encapsulation socket so pass the skb to
1484		 * the socket's udp_encap_rcv() hook. Otherwise, just
1485		 * fall through and pass this up the UDP socket.
1486		 * up->encap_rcv() returns the following value:
1487		 * =0 if skb was successfully passed to the encap
1488		 *    handler or was discarded by it.
1489		 * >0 if skb should be passed on to UDP.
1490		 * <0 if skb should be resubmitted as proto -N
1491		 */
1492
1493		/* if we're overly short, let UDP handle it */
1494		encap_rcv = ACCESS_ONCE(up->encap_rcv);
1495		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1496			int ret;
1497
1498			ret = encap_rcv(sk, skb);
1499			if (ret <= 0) {
1500				UDP_INC_STATS_BH(sock_net(sk),
1501						 UDP_MIB_INDATAGRAMS,
1502						 is_udplite);
1503				return -ret;
1504			}
1505		}
1506
1507		/* FALLTHROUGH -- it's a UDP Packet */
1508	}
1509
1510	/*
1511	 * 	UDP-Lite specific tests, ignored on UDP sockets
1512	 */
1513	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
1514
1515		/*
1516		 * MIB statistics other than incrementing the error count are
1517		 * disabled for the following two types of errors: these depend
1518		 * on the application settings, not on the functioning of the
1519		 * protocol stack as such.
1520		 *
1521		 * RFC 3828 here recommends (sec 3.3): "There should also be a
1522		 * way ... to ... at least let the receiving application block
1523		 * delivery of packets with coverage values less than a value
1524		 * provided by the application."
1525		 */
1526		if (up->pcrlen == 0) {          /* full coverage was set  */
1527			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: partial coverage %d while full coverage %d requested\n",
1528				       UDP_SKB_CB(skb)->cscov, skb->len);
1529			goto drop;
1530		}
1531		/* The next case involves violating the min. coverage requested
1532		 * by the receiver. This is subtle: if receiver wants x and x is
1533		 * greater than the buffersize/MTU then receiver will complain
1534		 * that it wants x while sender emits packets of smaller size y.
1535		 * Therefore the above ...()->partial_cov statement is essential.
1536		 */
1537		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1538			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: coverage %d too small, need min %d\n",
1539				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
1540			goto drop;
1541		}
1542	}
1543
1544	if (rcu_access_pointer(sk->sk_filter) &&
1545	    udp_lib_checksum_complete(skb))
1546		goto csum_error;
1547
1548
1549	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
1550		goto drop;
1551
1552	rc = 0;
1553
1554	ipv4_pktinfo_prepare(sk, skb);
1555	bh_lock_sock(sk);
1556	if (!sock_owned_by_user(sk))
1557		rc = __udp_queue_rcv_skb(sk, skb);
1558	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
1559		bh_unlock_sock(sk);
1560		goto drop;
1561	}
1562	bh_unlock_sock(sk);
1563
1564	return rc;
1565
1566csum_error:
1567	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
1568drop:
1569	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1570	atomic_inc(&sk->sk_drops);
1571	kfree_skb(skb);
1572	return -1;
1573}
1574
1575
1576static void flush_stack(struct sock **stack, unsigned int count,
1577			struct sk_buff *skb, unsigned int final)
1578{
1579	unsigned int i;
1580	struct sk_buff *skb1 = NULL;
1581	struct sock *sk;
1582
1583	for (i = 0; i < count; i++) {
1584		sk = stack[i];
1585		if (likely(skb1 == NULL))
1586			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
1587
1588		if (!skb1) {
1589			atomic_inc(&sk->sk_drops);
1590			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1591					 IS_UDPLITE(sk));
1592			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1593					 IS_UDPLITE(sk));
1594		}
1595
1596		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1597			skb1 = NULL;
1598	}
1599	if (unlikely(skb1))
1600		kfree_skb(skb1);
1601}
1602
1603/* For TCP sockets, sk_rx_dst is protected by socket lock
1604 * For UDP, we use xchg() to guard against concurrent changes.
1605 */
1606static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
1607{
1608	struct dst_entry *old;
1609
1610	dst_hold(dst);
1611	old = xchg(&sk->sk_rx_dst, dst);
1612	dst_release(old);
1613}
1614
1615/*
1616 *	Multicasts and broadcasts go to each listener.
1617 *
1618 *	Note: called only from the BH handler context.
1619 */
1620static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1621				    struct udphdr  *uh,
1622				    __be32 saddr, __be32 daddr,
1623				    struct udp_table *udptable)
1624{
1625	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1626	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1627	int dif;
1628	unsigned int i, count = 0;
1629
1630	spin_lock(&hslot->lock);
1631	sk = sk_nulls_head(&hslot->head);
1632	dif = skb->dev->ifindex;
1633	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1634	while (sk) {
1635		stack[count++] = sk;
1636		sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1637				       daddr, uh->source, saddr, dif);
1638		if (unlikely(count == ARRAY_SIZE(stack))) {
1639			if (!sk)
1640				break;
1641			flush_stack(stack, count, skb, ~0);
1642			count = 0;
1643		}
1644	}
1645	/*
1646	 * before releasing chain lock, we must take a reference on sockets
1647	 */
1648	for (i = 0; i < count; i++)
1649		sock_hold(stack[i]);
1650
1651	spin_unlock(&hslot->lock);
1652
1653	/*
1654	 * do the slow work with no lock held
1655	 */
1656	if (count) {
1657		flush_stack(stack, count, skb, count - 1);
1658
1659		for (i = 0; i < count; i++)
1660			sock_put(stack[i]);
1661	} else {
1662		kfree_skb(skb);
1663	}
1664	return 0;
1665}
1666
1667/* Initialize UDP checksum. If exited with zero value (success),
1668 * CHECKSUM_UNNECESSARY means, that no more checks are required.
1669 * Otherwise, csum completion requires chacksumming packet body,
1670 * including udp header and folding it to skb->csum.
1671 */
1672static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
1673				 int proto)
1674{
1675	const struct iphdr *iph;
1676	int err;
1677
1678	UDP_SKB_CB(skb)->partial_cov = 0;
1679	UDP_SKB_CB(skb)->cscov = skb->len;
1680
1681	if (proto == IPPROTO_UDPLITE) {
1682		err = udplite_checksum_init(skb, uh);
1683		if (err)
1684			return err;
1685	}
1686
1687	iph = ip_hdr(skb);
1688	if (uh->check == 0) {
1689		skb->ip_summed = CHECKSUM_UNNECESSARY;
1690	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
1691		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1692				      proto, skb->csum))
1693			skb->ip_summed = CHECKSUM_UNNECESSARY;
1694	}
1695	if (!skb_csum_unnecessary(skb))
1696		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1697					       skb->len, proto, 0);
1698	/* Probably, we should checksum udp header (it should be in cache
1699	 * in any case) and data in tiny packets (< rx copybreak).
1700	 */
1701
1702	return 0;
1703}
1704
1705/*
1706 *	All we need to do is get the socket, and then do a checksum.
1707 */
1708
1709int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1710		   int proto)
1711{
1712	struct sock *sk;
1713	struct udphdr *uh;
1714	unsigned short ulen;
1715	struct rtable *rt = skb_rtable(skb);
1716	__be32 saddr, daddr;
1717	struct net *net = dev_net(skb->dev);
1718
1719	/*
1720	 *  Validate the packet.
1721	 */
1722	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1723		goto drop;		/* No space for header. */
1724
1725	uh   = udp_hdr(skb);
1726	ulen = ntohs(uh->len);
1727	saddr = ip_hdr(skb)->saddr;
1728	daddr = ip_hdr(skb)->daddr;
1729
1730	if (ulen > skb->len)
1731		goto short_packet;
1732
1733	if (proto == IPPROTO_UDP) {
1734		/* UDP validates ulen. */
1735		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
1736			goto short_packet;
1737		uh = udp_hdr(skb);
1738	}
1739
1740	if (udp4_csum_init(skb, uh, proto))
1741		goto csum_error;
1742
1743	sk = skb_steal_sock(skb);
1744	if (sk) {
1745		struct dst_entry *dst = skb_dst(skb);
1746		int ret;
1747
1748		if (unlikely(sk->sk_rx_dst != dst))
1749			udp_sk_rx_dst_set(sk, dst);
1750
1751		ret = udp_queue_rcv_skb(sk, skb);
1752		sock_put(sk);
1753		/* a return value > 0 means to resubmit the input, but
1754		 * it wants the return to be -protocol, or 0
1755		 */
1756		if (ret > 0)
1757			return -ret;
1758		return 0;
1759	} else {
1760		if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1761			return __udp4_lib_mcast_deliver(net, skb, uh,
1762					saddr, daddr, udptable);
1763
1764		sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1765	}
1766
1767	if (sk != NULL) {
1768		int ret;
1769
1770		ret = udp_queue_rcv_skb(sk, skb);
1771		sock_put(sk);
1772
1773		/* a return value > 0 means to resubmit the input, but
1774		 * it wants the return to be -protocol, or 0
1775		 */
1776		if (ret > 0)
1777			return -ret;
1778		return 0;
1779	}
1780
1781	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1782		goto drop;
1783	nf_reset(skb);
1784
1785	/* No socket. Drop packet silently, if checksum is wrong */
1786	if (udp_lib_checksum_complete(skb))
1787		goto csum_error;
1788
1789	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1790	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
1791
1792	/*
1793	 * Hmm.  We got an UDP packet to a port to which we
1794	 * don't wanna listen.  Ignore it.
1795	 */
1796	kfree_skb(skb);
1797	return 0;
1798
1799short_packet:
1800	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1801		       proto == IPPROTO_UDPLITE ? "Lite" : "",
1802		       &saddr, ntohs(uh->source),
1803		       ulen, skb->len,
1804		       &daddr, ntohs(uh->dest));
1805	goto drop;
1806
1807csum_error:
1808	/*
1809	 * RFC1122: OK.  Discards the bad packet silently (as far as
1810	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
1811	 */
1812	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1813		       proto == IPPROTO_UDPLITE ? "Lite" : "",
1814		       &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1815		       ulen);
1816	UDP_INC_STATS_BH(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
1817drop:
1818	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1819	kfree_skb(skb);
1820	return 0;
1821}
1822
1823/* We can only early demux multicast if there is a single matching socket.
1824 * If more than one socket found returns NULL
1825 */
1826static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
1827						  __be16 loc_port, __be32 loc_addr,
1828						  __be16 rmt_port, __be32 rmt_addr,
1829						  int dif)
1830{
1831	struct sock *sk, *result;
1832	struct hlist_nulls_node *node;
1833	unsigned short hnum = ntohs(loc_port);
1834	unsigned int count, slot = udp_hashfn(net, hnum, udp_table.mask);
1835	struct udp_hslot *hslot = &udp_table.hash[slot];
1836
1837	rcu_read_lock();
1838begin:
1839	count = 0;
1840	result = NULL;
1841	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
1842		if (__udp_is_mcast_sock(net, sk,
1843					loc_port, loc_addr,
1844					rmt_port, rmt_addr,
1845					dif, hnum)) {
1846			result = sk;
1847			++count;
1848		}
1849	}
1850	/*
1851	 * if the nulls value we got at the end of this lookup is
1852	 * not the expected one, we must restart lookup.
1853	 * We probably met an item that was moved to another chain.
1854	 */
1855	if (get_nulls_value(node) != slot)
1856		goto begin;
1857
1858	if (result) {
1859		if (count != 1 ||
1860		    unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
1861			result = NULL;
1862		else if (unlikely(!__udp_is_mcast_sock(net, result,
1863						       loc_port, loc_addr,
1864						       rmt_port, rmt_addr,
1865						       dif, hnum))) {
1866			sock_put(result);
1867			result = NULL;
1868		}
1869	}
1870	rcu_read_unlock();
1871	return result;
1872}
1873
1874/* For unicast we should only early demux connected sockets or we can
1875 * break forwarding setups.  The chains here can be long so only check
1876 * if the first socket is an exact match and if not move on.
1877 */
1878static struct sock *__udp4_lib_demux_lookup(struct net *net,
1879					    __be16 loc_port, __be32 loc_addr,
1880					    __be16 rmt_port, __be32 rmt_addr,
1881					    int dif)
1882{
1883	struct sock *sk, *result;
1884	struct hlist_nulls_node *node;
1885	unsigned short hnum = ntohs(loc_port);
1886	unsigned int hash2 = udp4_portaddr_hash(net, loc_addr, hnum);
1887	unsigned int slot2 = hash2 & udp_table.mask;
1888	struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
1889	INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr)
1890	const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
1891
1892	rcu_read_lock();
1893	result = NULL;
1894	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
1895		if (INET_MATCH(sk, net, acookie,
1896			       rmt_addr, loc_addr, ports, dif))
1897			result = sk;
1898		/* Only check first socket in chain */
1899		break;
1900	}
1901
1902	if (result) {
1903		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
1904			result = NULL;
1905		else if (unlikely(!INET_MATCH(sk, net, acookie,
1906					      rmt_addr, loc_addr,
1907					      ports, dif))) {
1908			sock_put(result);
1909			result = NULL;
1910		}
1911	}
1912	rcu_read_unlock();
1913	return result;
1914}
1915
1916void udp_v4_early_demux(struct sk_buff *skb)
1917{
1918	struct net *net = dev_net(skb->dev);
1919	const struct iphdr *iph;
1920	const struct udphdr *uh;
1921	struct sock *sk;
1922	struct dst_entry *dst;
1923	int dif = skb->dev->ifindex;
1924
1925	/* validate the packet */
1926	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
1927		return;
1928
1929	iph = ip_hdr(skb);
1930	uh = udp_hdr(skb);
1931
1932	if (skb->pkt_type == PACKET_BROADCAST ||
1933	    skb->pkt_type == PACKET_MULTICAST)
1934		sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
1935						   uh->source, iph->saddr, dif);
1936	else if (skb->pkt_type == PACKET_HOST)
1937		sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
1938					     uh->source, iph->saddr, dif);
1939	else
1940		return;
1941
1942	if (!sk)
1943		return;
1944
1945	skb->sk = sk;
1946	skb->destructor = sock_edemux;
1947	dst = sk->sk_rx_dst;
1948
1949	if (dst)
1950		dst = dst_check(dst, 0);
1951	if (dst)
1952		skb_dst_set_noref(skb, dst);
1953}
1954
1955int udp_rcv(struct sk_buff *skb)
1956{
1957	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1958}
1959
1960void udp_destroy_sock(struct sock *sk)
1961{
1962	struct udp_sock *up = udp_sk(sk);
1963	bool slow = lock_sock_fast(sk);
1964	udp_flush_pending_frames(sk);
1965	unlock_sock_fast(sk, slow);
1966	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1967		void (*encap_destroy)(struct sock *sk);
1968		encap_destroy = ACCESS_ONCE(up->encap_destroy);
1969		if (encap_destroy)
1970			encap_destroy(sk);
1971	}
1972}
1973
1974/*
1975 *	Socket option code for UDP
1976 */
1977int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1978		       char __user *optval, unsigned int optlen,
1979		       int (*push_pending_frames)(struct sock *))
1980{
1981	struct udp_sock *up = udp_sk(sk);
1982	int val;
1983	int err = 0;
1984	int is_udplite = IS_UDPLITE(sk);
1985
1986	if (optlen < sizeof(int))
1987		return -EINVAL;
1988
1989	if (get_user(val, (int __user *)optval))
1990		return -EFAULT;
1991
1992	switch (optname) {
1993	case UDP_CORK:
1994		if (val != 0) {
1995			up->corkflag = 1;
1996		} else {
1997			up->corkflag = 0;
1998			lock_sock(sk);
1999			(*push_pending_frames)(sk);
2000			release_sock(sk);
2001		}
2002		break;
2003
2004	case UDP_ENCAP:
2005		switch (val) {
2006		case 0:
2007		case UDP_ENCAP_ESPINUDP:
2008		case UDP_ENCAP_ESPINUDP_NON_IKE:
2009			up->encap_rcv = xfrm4_udp_encap_rcv;
2010			/* FALLTHROUGH */
2011		case UDP_ENCAP_L2TPINUDP:
2012			up->encap_type = val;
2013			udp_encap_enable();
2014			break;
2015		default:
2016			err = -ENOPROTOOPT;
2017			break;
2018		}
2019		break;
2020
2021	/*
2022	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
2023	 */
2024	/* The sender sets actual checksum coverage length via this option.
2025	 * The case coverage > packet length is handled by send module. */
2026	case UDPLITE_SEND_CSCOV:
2027		if (!is_udplite)         /* Disable the option on UDP sockets */
2028			return -ENOPROTOOPT;
2029		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
2030			val = 8;
2031		else if (val > USHRT_MAX)
2032			val = USHRT_MAX;
2033		up->pcslen = val;
2034		up->pcflag |= UDPLITE_SEND_CC;
2035		break;
2036
2037	/* The receiver specifies a minimum checksum coverage value. To make
2038	 * sense, this should be set to at least 8 (as done below). If zero is
2039	 * used, this again means full checksum coverage.                     */
2040	case UDPLITE_RECV_CSCOV:
2041		if (!is_udplite)         /* Disable the option on UDP sockets */
2042			return -ENOPROTOOPT;
2043		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
2044			val = 8;
2045		else if (val > USHRT_MAX)
2046			val = USHRT_MAX;
2047		up->pcrlen = val;
2048		up->pcflag |= UDPLITE_RECV_CC;
2049		break;
2050
2051	default:
2052		err = -ENOPROTOOPT;
2053		break;
2054	}
2055
2056	return err;
2057}
2058EXPORT_SYMBOL(udp_lib_setsockopt);
2059
2060int udp_setsockopt(struct sock *sk, int level, int optname,
2061		   char __user *optval, unsigned int optlen)
2062{
2063	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2064		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2065					  udp_push_pending_frames);
2066	return ip_setsockopt(sk, level, optname, optval, optlen);
2067}
2068
2069#ifdef CONFIG_COMPAT
2070int compat_udp_setsockopt(struct sock *sk, int level, int optname,
2071			  char __user *optval, unsigned int optlen)
2072{
2073	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2074		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
2075					  udp_push_pending_frames);
2076	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
2077}
2078#endif
2079
2080int udp_lib_getsockopt(struct sock *sk, int level, int optname,
2081		       char __user *optval, int __user *optlen)
2082{
2083	struct udp_sock *up = udp_sk(sk);
2084	int val, len;
2085
2086	if (get_user(len, optlen))
2087		return -EFAULT;
2088
2089	len = min_t(unsigned int, len, sizeof(int));
2090
2091	if (len < 0)
2092		return -EINVAL;
2093
2094	switch (optname) {
2095	case UDP_CORK:
2096		val = up->corkflag;
2097		break;
2098
2099	case UDP_ENCAP:
2100		val = up->encap_type;
2101		break;
2102
2103	/* The following two cannot be changed on UDP sockets, the return is
2104	 * always 0 (which corresponds to the full checksum coverage of UDP). */
2105	case UDPLITE_SEND_CSCOV:
2106		val = up->pcslen;
2107		break;
2108
2109	case UDPLITE_RECV_CSCOV:
2110		val = up->pcrlen;
2111		break;
2112
2113	default:
2114		return -ENOPROTOOPT;
2115	}
2116
2117	if (put_user(len, optlen))
2118		return -EFAULT;
2119	if (copy_to_user(optval, &val, len))
2120		return -EFAULT;
2121	return 0;
2122}
2123EXPORT_SYMBOL(udp_lib_getsockopt);
2124
2125int udp_getsockopt(struct sock *sk, int level, int optname,
2126		   char __user *optval, int __user *optlen)
2127{
2128	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2129		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2130	return ip_getsockopt(sk, level, optname, optval, optlen);
2131}
2132
2133#ifdef CONFIG_COMPAT
2134int compat_udp_getsockopt(struct sock *sk, int level, int optname,
2135				 char __user *optval, int __user *optlen)
2136{
2137	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
2138		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
2139	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
2140}
2141#endif
2142/**
2143 * 	udp_poll - wait for a UDP event.
2144 *	@file - file struct
2145 *	@sock - socket
2146 *	@wait - poll table
2147 *
2148 *	This is same as datagram poll, except for the special case of
2149 *	blocking sockets. If application is using a blocking fd
2150 *	and a packet with checksum error is in the queue;
2151 *	then it could get return from select indicating data available
2152 *	but then block when reading it. Add special case code
2153 *	to work around these arguably broken applications.
2154 */
2155unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
2156{
2157	unsigned int mask = datagram_poll(file, sock, wait);
2158	struct sock *sk = sock->sk;
2159
2160	sock_rps_record_flow(sk);
2161
2162	/* Check for false positives due to checksum errors */
2163	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
2164	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
2165		mask &= ~(POLLIN | POLLRDNORM);
2166
2167	return mask;
2168
2169}
2170EXPORT_SYMBOL(udp_poll);
2171
2172struct proto udp_prot = {
2173	.name		   = "UDP",
2174	.owner		   = THIS_MODULE,
2175	.close		   = udp_lib_close,
2176	.connect	   = ip4_datagram_connect,
2177	.disconnect	   = udp_disconnect,
2178	.ioctl		   = udp_ioctl,
2179	.destroy	   = udp_destroy_sock,
2180	.setsockopt	   = udp_setsockopt,
2181	.getsockopt	   = udp_getsockopt,
2182	.sendmsg	   = udp_sendmsg,
2183	.recvmsg	   = udp_recvmsg,
2184	.sendpage	   = udp_sendpage,
2185	.backlog_rcv	   = __udp_queue_rcv_skb,
2186	.release_cb	   = ip4_datagram_release_cb,
2187	.hash		   = udp_lib_hash,
2188	.unhash		   = udp_lib_unhash,
2189	.rehash		   = udp_v4_rehash,
2190	.get_port	   = udp_v4_get_port,
2191	.memory_allocated  = &udp_memory_allocated,
2192	.sysctl_mem	   = sysctl_udp_mem,
2193	.sysctl_wmem	   = &sysctl_udp_wmem_min,
2194	.sysctl_rmem	   = &sysctl_udp_rmem_min,
2195	.obj_size	   = sizeof(struct udp_sock),
2196	.slab_flags	   = SLAB_DESTROY_BY_RCU,
2197	.h.udp_table	   = &udp_table,
2198#ifdef CONFIG_COMPAT
2199	.compat_setsockopt = compat_udp_setsockopt,
2200	.compat_getsockopt = compat_udp_getsockopt,
2201#endif
2202	.clear_sk	   = sk_prot_clear_portaddr_nulls,
2203};
2204EXPORT_SYMBOL(udp_prot);
2205
2206/* ------------------------------------------------------------------------ */
2207#ifdef CONFIG_PROC_FS
2208
2209static struct sock *udp_get_first(struct seq_file *seq, int start)
2210{
2211	struct sock *sk;
2212	struct udp_iter_state *state = seq->private;
2213	struct net *net = seq_file_net(seq);
2214
2215	for (state->bucket = start; state->bucket <= state->udp_table->mask;
2216	     ++state->bucket) {
2217		struct hlist_nulls_node *node;
2218		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
2219
2220		if (hlist_nulls_empty(&hslot->head))
2221			continue;
2222
2223		spin_lock_bh(&hslot->lock);
2224		sk_nulls_for_each(sk, node, &hslot->head) {
2225			if (!net_eq(sock_net(sk), net))
2226				continue;
2227			if (sk->sk_family == state->family)
2228				goto found;
2229		}
2230		spin_unlock_bh(&hslot->lock);
2231	}
2232	sk = NULL;
2233found:
2234	return sk;
2235}
2236
2237static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
2238{
2239	struct udp_iter_state *state = seq->private;
2240	struct net *net = seq_file_net(seq);
2241
2242	do {
2243		sk = sk_nulls_next(sk);
2244	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
2245
2246	if (!sk) {
2247		if (state->bucket <= state->udp_table->mask)
2248			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2249		return udp_get_first(seq, state->bucket + 1);
2250	}
2251	return sk;
2252}
2253
2254static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2255{
2256	struct sock *sk = udp_get_first(seq, 0);
2257
2258	if (sk)
2259		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2260			--pos;
2261	return pos ? NULL : sk;
2262}
2263
2264static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2265{
2266	struct udp_iter_state *state = seq->private;
2267	state->bucket = MAX_UDP_PORTS;
2268
2269	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2270}
2271
2272static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2273{
2274	struct sock *sk;
2275
2276	if (v == SEQ_START_TOKEN)
2277		sk = udp_get_idx(seq, 0);
2278	else
2279		sk = udp_get_next(seq, v);
2280
2281	++*pos;
2282	return sk;
2283}
2284
2285static void udp_seq_stop(struct seq_file *seq, void *v)
2286{
2287	struct udp_iter_state *state = seq->private;
2288
2289	if (state->bucket <= state->udp_table->mask)
2290		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2291}
2292
2293int udp_seq_open(struct inode *inode, struct file *file)
2294{
2295	struct udp_seq_afinfo *afinfo = PDE_DATA(inode);
2296	struct udp_iter_state *s;
2297	int err;
2298
2299	err = seq_open_net(inode, file, &afinfo->seq_ops,
2300			   sizeof(struct udp_iter_state));
2301	if (err < 0)
2302		return err;
2303
2304	s = ((struct seq_file *)file->private_data)->private;
2305	s->family		= afinfo->family;
2306	s->udp_table		= afinfo->udp_table;
2307	return err;
2308}
2309EXPORT_SYMBOL(udp_seq_open);
2310
2311/* ------------------------------------------------------------------------ */
2312int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2313{
2314	struct proc_dir_entry *p;
2315	int rc = 0;
2316
2317	afinfo->seq_ops.start		= udp_seq_start;
2318	afinfo->seq_ops.next		= udp_seq_next;
2319	afinfo->seq_ops.stop		= udp_seq_stop;
2320
2321	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2322			     afinfo->seq_fops, afinfo);
2323	if (!p)
2324		rc = -ENOMEM;
2325	return rc;
2326}
2327EXPORT_SYMBOL(udp_proc_register);
2328
2329void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2330{
2331	remove_proc_entry(afinfo->name, net->proc_net);
2332}
2333EXPORT_SYMBOL(udp_proc_unregister);
2334
2335/* ------------------------------------------------------------------------ */
2336static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2337		int bucket)
2338{
2339	struct inet_sock *inet = inet_sk(sp);
2340	__be32 dest = inet->inet_daddr;
2341	__be32 src  = inet->inet_rcv_saddr;
2342	__u16 destp	  = ntohs(inet->inet_dport);
2343	__u16 srcp	  = ntohs(inet->inet_sport);
2344
2345	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2346		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
2347		bucket, src, srcp, dest, destp, sp->sk_state,
2348		sk_wmem_alloc_get(sp),
2349		sk_rmem_alloc_get(sp),
2350		0, 0L, 0,
2351		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
2352		0, sock_i_ino(sp),
2353		atomic_read(&sp->sk_refcnt), sp,
2354		atomic_read(&sp->sk_drops));
2355}
2356
2357int udp4_seq_show(struct seq_file *seq, void *v)
2358{
2359	seq_setwidth(seq, 127);
2360	if (v == SEQ_START_TOKEN)
2361		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
 
2362			   "rx_queue tr tm->when retrnsmt   uid  timeout "
2363			   "inode ref pointer drops");
2364	else {
2365		struct udp_iter_state *state = seq->private;
 
2366
2367		udp4_format_sock(v, seq, state->bucket);
 
2368	}
2369	seq_pad(seq, '\n');
2370	return 0;
2371}
2372
2373static const struct file_operations udp_afinfo_seq_fops = {
2374	.owner    = THIS_MODULE,
2375	.open     = udp_seq_open,
2376	.read     = seq_read,
2377	.llseek   = seq_lseek,
2378	.release  = seq_release_net
2379};
2380
2381/* ------------------------------------------------------------------------ */
2382static struct udp_seq_afinfo udp4_seq_afinfo = {
2383	.name		= "udp",
2384	.family		= AF_INET,
2385	.udp_table	= &udp_table,
2386	.seq_fops	= &udp_afinfo_seq_fops,
2387	.seq_ops	= {
2388		.show		= udp4_seq_show,
2389	},
2390};
2391
2392static int __net_init udp4_proc_init_net(struct net *net)
2393{
2394	return udp_proc_register(net, &udp4_seq_afinfo);
2395}
2396
2397static void __net_exit udp4_proc_exit_net(struct net *net)
2398{
2399	udp_proc_unregister(net, &udp4_seq_afinfo);
2400}
2401
2402static struct pernet_operations udp4_net_ops = {
2403	.init = udp4_proc_init_net,
2404	.exit = udp4_proc_exit_net,
2405};
2406
2407int __init udp4_proc_init(void)
2408{
2409	return register_pernet_subsys(&udp4_net_ops);
2410}
2411
2412void udp4_proc_exit(void)
2413{
2414	unregister_pernet_subsys(&udp4_net_ops);
2415}
2416#endif /* CONFIG_PROC_FS */
2417
2418static __initdata unsigned long uhash_entries;
2419static int __init set_uhash_entries(char *str)
2420{
2421	ssize_t ret;
2422
2423	if (!str)
2424		return 0;
2425
2426	ret = kstrtoul(str, 0, &uhash_entries);
2427	if (ret)
2428		return 0;
2429
2430	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2431		uhash_entries = UDP_HTABLE_SIZE_MIN;
2432	return 1;
2433}
2434__setup("uhash_entries=", set_uhash_entries);
2435
2436void __init udp_table_init(struct udp_table *table, const char *name)
2437{
2438	unsigned int i;
2439
2440	table->hash = alloc_large_system_hash(name,
2441					      2 * sizeof(struct udp_hslot),
2442					      uhash_entries,
2443					      21, /* one slot per 2 MB */
2444					      0,
2445					      &table->log,
2446					      &table->mask,
2447					      UDP_HTABLE_SIZE_MIN,
2448					      64 * 1024);
2449
2450	table->hash2 = table->hash + (table->mask + 1);
2451	for (i = 0; i <= table->mask; i++) {
2452		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
2453		table->hash[i].count = 0;
2454		spin_lock_init(&table->hash[i].lock);
2455	}
2456	for (i = 0; i <= table->mask; i++) {
2457		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
2458		table->hash2[i].count = 0;
2459		spin_lock_init(&table->hash2[i].lock);
2460	}
2461}
2462
2463void __init udp_init(void)
2464{
2465	unsigned long limit;
2466
2467	udp_table_init(&udp_table, "UDP");
2468	limit = nr_free_buffer_pages() / 8;
2469	limit = max(limit, 128UL);
2470	sysctl_udp_mem[0] = limit / 4 * 3;
2471	sysctl_udp_mem[1] = limit;
2472	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2473
2474	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2475	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2476}
2477
2478struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
2479				       netdev_features_t features)
2480{
2481	struct sk_buff *segs = ERR_PTR(-EINVAL);
2482	u16 mac_offset = skb->mac_header;
2483	int mac_len = skb->mac_len;
2484	int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
2485	__be16 protocol = skb->protocol;
2486	netdev_features_t enc_features;
2487	int outer_hlen;
2488
2489	if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
2490		goto out;
2491
2492	skb->encapsulation = 0;
2493	__skb_pull(skb, tnl_hlen);
2494	skb_reset_mac_header(skb);
2495	skb_set_network_header(skb, skb_inner_network_offset(skb));
2496	skb->mac_len = skb_inner_network_offset(skb);
2497	skb->protocol = htons(ETH_P_TEB);
2498
2499	/* segment inner packet. */
2500	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
2501	segs = skb_mac_gso_segment(skb, enc_features);
2502	if (!segs || IS_ERR(segs)) {
2503		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
2504				     mac_len);
 
 
 
 
 
 
 
 
2505		goto out;
2506	}
2507
2508	outer_hlen = skb_tnl_header_len(skb);
2509	skb = segs;
2510	do {
2511		struct udphdr *uh;
2512		int udp_offset = outer_hlen - tnl_hlen;
2513
2514		skb_reset_inner_headers(skb);
2515		skb->encapsulation = 1;
 
2516
2517		skb->mac_len = mac_len;
2518
2519		skb_push(skb, outer_hlen);
2520		skb_reset_mac_header(skb);
2521		skb_set_network_header(skb, mac_len);
2522		skb_set_transport_header(skb, udp_offset);
2523		uh = udp_hdr(skb);
2524		uh->len = htons(skb->len - udp_offset);
2525
2526		/* csum segment if tunnel sets skb with csum. */
2527		if (protocol == htons(ETH_P_IP) && unlikely(uh->check)) {
2528			struct iphdr *iph = ip_hdr(skb);
2529
2530			uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
2531						       skb->len - udp_offset,
2532						       IPPROTO_UDP, 0);
2533			uh->check = csum_fold(skb_checksum(skb, udp_offset,
2534							   skb->len - udp_offset, 0));
2535			if (uh->check == 0)
2536				uh->check = CSUM_MANGLED_0;
2537
2538		} else if (protocol == htons(ETH_P_IPV6)) {
2539			struct ipv6hdr *ipv6h = ipv6_hdr(skb);
2540			u32 len = skb->len - udp_offset;
2541
2542			uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
2543						     len, IPPROTO_UDP, 0);
2544			uh->check = csum_fold(skb_checksum(skb, udp_offset, len, 0));
2545			if (uh->check == 0)
2546				uh->check = CSUM_MANGLED_0;
2547			skb->ip_summed = CHECKSUM_NONE;
2548		}
2549
2550		skb->protocol = protocol;
2551	} while ((skb = skb->next));
 
 
2552out:
2553	return segs;
2554}