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#include <asm/system.h>
  81#include <asm/uaccess.h>
 
 
  82#include <asm/ioctls.h>
  83#include <linux/bootmem.h>
  84#include <linux/highmem.h>
  85#include <linux/swap.h>
  86#include <linux/types.h>
  87#include <linux/fcntl.h>
  88#include <linux/module.h>
  89#include <linux/socket.h>
  90#include <linux/sockios.h>
  91#include <linux/igmp.h>
 
  92#include <linux/in.h>
  93#include <linux/errno.h>
  94#include <linux/timer.h>
  95#include <linux/mm.h>
  96#include <linux/inet.h>
  97#include <linux/netdevice.h>
  98#include <linux/slab.h>
  99#include <net/tcp_states.h>
 100#include <linux/skbuff.h>
 101#include <linux/proc_fs.h>
 102#include <linux/seq_file.h>
 103#include <net/net_namespace.h>
 104#include <net/icmp.h>
 
 
 105#include <net/route.h>
 106#include <net/checksum.h>
 107#include <net/xfrm.h>
 108#include <trace/events/udp.h>
 
 
 
 
 109#include "udp_impl.h"
 
 
 
 
 
 
 110
 111struct udp_table udp_table __read_mostly;
 112EXPORT_SYMBOL(udp_table);
 113
 114long sysctl_udp_mem[3] __read_mostly;
 115EXPORT_SYMBOL(sysctl_udp_mem);
 116
 117int sysctl_udp_rmem_min __read_mostly;
 118EXPORT_SYMBOL(sysctl_udp_rmem_min);
 119
 120int sysctl_udp_wmem_min __read_mostly;
 121EXPORT_SYMBOL(sysctl_udp_wmem_min);
 122
 123atomic_long_t udp_memory_allocated;
 124EXPORT_SYMBOL(udp_memory_allocated);
 
 
 125
 126#define MAX_UDP_PORTS 65536
 127#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
 
 
 
 
 
 128
 129static int udp_lib_lport_inuse(struct net *net, __u16 num,
 130			       const struct udp_hslot *hslot,
 131			       unsigned long *bitmap,
 132			       struct sock *sk,
 133			       int (*saddr_comp)(const struct sock *sk1,
 134						 const struct sock *sk2),
 135			       unsigned int log)
 136{
 137	struct sock *sk2;
 138	struct hlist_nulls_node *node;
 139
 140	sk_nulls_for_each(sk2, node, &hslot->head)
 141		if (net_eq(sock_net(sk2), net) &&
 142		    sk2 != sk &&
 143		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
 144		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 145		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 146		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 147		    (*saddr_comp)(sk, sk2)) {
 148			if (bitmap)
 
 
 
 
 
 
 
 149				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
 150					  bitmap);
 151			else
 152				return 1;
 153		}
 
 154	return 0;
 155}
 156
 157/*
 158 * Note: we still hold spinlock of primary hash chain, so no other writer
 159 * can insert/delete a socket with local_port == num
 160 */
 161static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 162			       struct udp_hslot *hslot2,
 163			       struct sock *sk,
 164			       int (*saddr_comp)(const struct sock *sk1,
 165						 const struct sock *sk2))
 166{
 167	struct sock *sk2;
 168	struct hlist_nulls_node *node;
 169	int res = 0;
 170
 171	spin_lock(&hslot2->lock);
 172	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
 173		if (net_eq(sock_net(sk2), net) &&
 174		    sk2 != sk &&
 175		    (udp_sk(sk2)->udp_port_hash == num) &&
 176		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 177		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 178		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 179		    (*saddr_comp)(sk, sk2)) {
 180			res = 1;
 
 
 
 
 
 
 181			break;
 182		}
 
 183	spin_unlock(&hslot2->lock);
 184	return res;
 185}
 186
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 187/**
 188 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
 189 *
 190 *  @sk:          socket struct in question
 191 *  @snum:        port number to look up
 192 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
 193 *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
 194 *                   with NULL address
 195 */
 196int udp_lib_get_port(struct sock *sk, unsigned short snum,
 197		       int (*saddr_comp)(const struct sock *sk1,
 198					 const struct sock *sk2),
 199		     unsigned int hash2_nulladdr)
 200{
 
 201	struct udp_hslot *hslot, *hslot2;
 202	struct udp_table *udptable = sk->sk_prot->h.udp_table;
 203	int    error = 1;
 204	struct net *net = sock_net(sk);
 
 205
 206	if (!snum) {
 207		int low, high, remaining;
 208		unsigned rand;
 209		unsigned short first, last;
 210		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
 
 
 
 211
 212		inet_get_local_port_range(&low, &high);
 213		remaining = (high - low) + 1;
 214
 215		rand = net_random();
 216		first = (((u64)rand * remaining) >> 32) + low;
 217		/*
 218		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
 219		 */
 220		rand = (rand | 1) * (udptable->mask + 1);
 221		last = first + udptable->mask + 1;
 222		do {
 223			hslot = udp_hashslot(udptable, net, first);
 224			bitmap_zero(bitmap, PORTS_PER_CHAIN);
 225			spin_lock_bh(&hslot->lock);
 226			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
 227					    saddr_comp, udptable->log);
 228
 229			snum = first;
 230			/*
 231			 * Iterate on all possible values of snum for this hash.
 232			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
 233			 * give us randomization and full range coverage.
 234			 */
 235			do {
 236				if (low <= snum && snum <= high &&
 237				    !test_bit(snum >> udptable->log, bitmap) &&
 238				    !inet_is_reserved_local_port(snum))
 239					goto found;
 240				snum += rand;
 241			} while (snum != first);
 242			spin_unlock_bh(&hslot->lock);
 
 243		} while (++first != last);
 244		goto fail;
 245	} else {
 246		hslot = udp_hashslot(udptable, net, snum);
 247		spin_lock_bh(&hslot->lock);
 248		if (hslot->count > 10) {
 249			int exist;
 250			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
 251
 252			slot2          &= udptable->mask;
 253			hash2_nulladdr &= udptable->mask;
 254
 255			hslot2 = udp_hashslot2(udptable, slot2);
 256			if (hslot->count < hslot2->count)
 257				goto scan_primary_hash;
 258
 259			exist = udp_lib_lport_inuse2(net, snum, hslot2,
 260						     sk, saddr_comp);
 261			if (!exist && (hash2_nulladdr != slot2)) {
 262				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
 263				exist = udp_lib_lport_inuse2(net, snum, hslot2,
 264							     sk, saddr_comp);
 265			}
 266			if (exist)
 267				goto fail_unlock;
 268			else
 269				goto found;
 270		}
 271scan_primary_hash:
 272		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
 273					saddr_comp, 0))
 274			goto fail_unlock;
 275	}
 276found:
 277	inet_sk(sk)->inet_num = snum;
 278	udp_sk(sk)->udp_port_hash = snum;
 279	udp_sk(sk)->udp_portaddr_hash ^= snum;
 280	if (sk_unhashed(sk)) {
 281		sk_nulls_add_node_rcu(sk, &hslot->head);
 
 
 
 
 
 
 
 
 282		hslot->count++;
 283		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 284
 285		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
 286		spin_lock(&hslot2->lock);
 287		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
 288					 &hslot2->head);
 
 
 
 
 
 289		hslot2->count++;
 290		spin_unlock(&hslot2->lock);
 291	}
 
 292	error = 0;
 293fail_unlock:
 294	spin_unlock_bh(&hslot->lock);
 295fail:
 296	return error;
 297}
 298EXPORT_SYMBOL(udp_lib_get_port);
 299
 300static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
 301{
 302	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
 303
 304	return 	(!ipv6_only_sock(sk2)  &&
 305		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
 306		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
 307}
 308
 309static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
 310				       unsigned int port)
 311{
 312	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 313}
 314
 315int udp_v4_get_port(struct sock *sk, unsigned short snum)
 316{
 317	unsigned int hash2_nulladdr =
 318		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
 319	unsigned int hash2_partial =
 320		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
 321
 322	/* precompute partial secondary hash */
 323	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
 324	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
 325}
 326
 327static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 328			 unsigned short hnum,
 329			 __be16 sport, __be32 daddr, __be16 dport, int dif)
 330{
 331	int score = -1;
 332
 333	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
 334			!ipv6_only_sock(sk)) {
 335		struct inet_sock *inet = inet_sk(sk);
 336
 337		score = (sk->sk_family == PF_INET ? 1 : 0);
 338		if (inet->inet_rcv_saddr) {
 339			if (inet->inet_rcv_saddr != daddr)
 340				return -1;
 341			score += 2;
 342		}
 343		if (inet->inet_daddr) {
 344			if (inet->inet_daddr != saddr)
 345				return -1;
 346			score += 2;
 347		}
 348		if (inet->inet_dport) {
 349			if (inet->inet_dport != sport)
 350				return -1;
 351			score += 2;
 352		}
 353		if (sk->sk_bound_dev_if) {
 354			if (sk->sk_bound_dev_if != dif)
 355				return -1;
 356			score += 2;
 357		}
 358	}
 
 
 
 
 
 
 
 
 
 
 359	return score;
 360}
 361
 362/*
 363 * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
 364 */
 365#define SCORE2_MAX (1 + 2 + 2 + 2)
 366static inline int compute_score2(struct sock *sk, struct net *net,
 367				 __be32 saddr, __be16 sport,
 368				 __be32 daddr, unsigned int hnum, int dif)
 369{
 370	int score = -1;
 371
 372	if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
 373		struct inet_sock *inet = inet_sk(sk);
 374
 375		if (inet->inet_rcv_saddr != daddr)
 376			return -1;
 377		if (inet->inet_num != hnum)
 378			return -1;
 379
 380		score = (sk->sk_family == PF_INET ? 1 : 0);
 381		if (inet->inet_daddr) {
 382			if (inet->inet_daddr != saddr)
 383				return -1;
 384			score += 2;
 385		}
 386		if (inet->inet_dport) {
 387			if (inet->inet_dport != sport)
 388				return -1;
 389			score += 2;
 390		}
 391		if (sk->sk_bound_dev_if) {
 392			if (sk->sk_bound_dev_if != dif)
 393				return -1;
 394			score += 2;
 395		}
 396	}
 397	return score;
 398}
 399
 400
 401/* called with read_rcu_lock() */
 402static struct sock *udp4_lib_lookup2(struct net *net,
 403		__be32 saddr, __be16 sport,
 404		__be32 daddr, unsigned int hnum, int dif,
 405		struct udp_hslot *hslot2, unsigned int slot2)
 
 
 406{
 407	struct sock *sk, *result;
 408	struct hlist_nulls_node *node;
 409	int score, badness;
 410
 411begin:
 412	result = NULL;
 413	badness = -1;
 414	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
 415		score = compute_score2(sk, net, saddr, sport,
 416				      daddr, hnum, dif);
 417		if (score > badness) {
 418			result = sk;
 
 
 
 
 
 
 419			badness = score;
 420			if (score == SCORE2_MAX)
 421				goto exact_match;
 422		}
 423	}
 424	/*
 425	 * if the nulls value we got at the end of this lookup is
 426	 * not the expected one, we must restart lookup.
 427	 * We probably met an item that was moved to another chain.
 428	 */
 429	if (get_nulls_value(node) != slot2)
 430		goto begin;
 431
 432	if (result) {
 433exact_match:
 434		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 435			result = NULL;
 436		else if (unlikely(compute_score2(result, net, saddr, sport,
 437				  daddr, hnum, dif) < badness)) {
 438			sock_put(result);
 439			goto begin;
 440		}
 441	}
 442	return result;
 443}
 444
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 445/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 446 * harder than this. -DaveM
 447 */
 448static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 449		__be16 sport, __be32 daddr, __be16 dport,
 450		int dif, struct udp_table *udptable)
 451{
 452	struct sock *sk, *result;
 453	struct hlist_nulls_node *node;
 454	unsigned short hnum = ntohs(dport);
 455	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 456	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
 457	int score, badness;
 458
 459	rcu_read_lock();
 460	if (hslot->count > 10) {
 461		hash2 = udp4_portaddr_hash(net, daddr, hnum);
 462		slot2 = hash2 & udptable->mask;
 463		hslot2 = &udptable->hash2[slot2];
 464		if (hslot->count < hslot2->count)
 465			goto begin;
 466
 467		result = udp4_lib_lookup2(net, saddr, sport,
 468					  daddr, hnum, dif,
 469					  hslot2, slot2);
 470		if (!result) {
 471			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
 472			slot2 = hash2 & udptable->mask;
 473			hslot2 = &udptable->hash2[slot2];
 474			if (hslot->count < hslot2->count)
 475				goto begin;
 476
 477			result = udp4_lib_lookup2(net, saddr, sport,
 478						  htonl(INADDR_ANY), hnum, dif,
 479						  hslot2, slot2);
 480		}
 481		rcu_read_unlock();
 482		return result;
 483	}
 484begin:
 485	result = NULL;
 486	badness = -1;
 487	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
 488		score = compute_score(sk, net, saddr, hnum, sport,
 489				      daddr, dport, dif);
 490		if (score > badness) {
 491			result = sk;
 492			badness = score;
 493		}
 494	}
 495	/*
 496	 * if the nulls value we got at the end of this lookup is
 497	 * not the expected one, we must restart lookup.
 498	 * We probably met an item that was moved to another chain.
 499	 */
 500	if (get_nulls_value(node) != slot)
 501		goto begin;
 502
 503	if (result) {
 504		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 505			result = NULL;
 506		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
 507				  daddr, dport, dif) < badness)) {
 508			sock_put(result);
 509			goto begin;
 510		}
 511	}
 512	rcu_read_unlock();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 513	return result;
 514}
 
 515
 516static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 517						 __be16 sport, __be16 dport,
 518						 struct udp_table *udptable)
 519{
 520	struct sock *sk;
 521	const struct iphdr *iph = ip_hdr(skb);
 522
 523	if (unlikely(sk = skb_steal_sock(skb)))
 524		return sk;
 525	else
 526		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
 527					 iph->daddr, dport, inet_iif(skb),
 528					 udptable);
 529}
 530
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 531struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 532			     __be32 daddr, __be16 dport, int dif)
 533{
 534	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
 
 
 
 
 
 
 535}
 536EXPORT_SYMBOL_GPL(udp4_lib_lookup);
 
 537
 538static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
 539					     __be16 loc_port, __be32 loc_addr,
 540					     __be16 rmt_port, __be32 rmt_addr,
 541					     int dif)
 542{
 543	struct hlist_nulls_node *node;
 544	struct sock *s = sk;
 545	unsigned short hnum = ntohs(loc_port);
 546
 547	sk_nulls_for_each_from(s, node) {
 548		struct inet_sock *inet = inet_sk(s);
 
 
 
 
 
 
 
 
 
 
 549
 550		if (!net_eq(sock_net(s), net) ||
 551		    udp_sk(s)->udp_port_hash != hnum ||
 552		    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
 553		    (inet->inet_dport != rmt_port && inet->inet_dport) ||
 554		    (inet->inet_rcv_saddr &&
 555		     inet->inet_rcv_saddr != loc_addr) ||
 556		    ipv6_only_sock(s) ||
 557		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
 558			continue;
 559		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 560			continue;
 561		goto found;
 
 
 562	}
 563	s = NULL;
 564found:
 565	return s;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 566}
 567
 568/*
 569 * This routine is called by the ICMP module when it gets some
 570 * sort of error condition.  If err < 0 then the socket should
 571 * be closed and the error returned to the user.  If err > 0
 572 * it's just the icmp type << 8 | icmp code.
 573 * Header points to the ip header of the error packet. We move
 574 * on past this. Then (as it used to claim before adjustment)
 575 * header points to the first 8 bytes of the udp header.  We need
 576 * to find the appropriate port.
 577 */
 578
 579void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 580{
 581	struct inet_sock *inet;
 582	const struct iphdr *iph = (const struct iphdr *)skb->data;
 583	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
 584	const int type = icmp_hdr(skb)->type;
 585	const int code = icmp_hdr(skb)->code;
 
 586	struct sock *sk;
 587	int harderr;
 588	int err;
 589	struct net *net = dev_net(skb->dev);
 590
 591	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
 592			iph->saddr, uh->source, skb->dev->ifindex, udptable);
 593	if (sk == NULL) {
 594		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 595		return;	/* No socket for error */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 596	}
 597
 598	err = 0;
 599	harderr = 0;
 600	inet = inet_sk(sk);
 601
 602	switch (type) {
 603	default:
 604	case ICMP_TIME_EXCEEDED:
 605		err = EHOSTUNREACH;
 606		break;
 607	case ICMP_SOURCE_QUENCH:
 608		goto out;
 609	case ICMP_PARAMETERPROB:
 610		err = EPROTO;
 611		harderr = 1;
 612		break;
 613	case ICMP_DEST_UNREACH:
 614		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 
 615			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
 616				err = EMSGSIZE;
 617				harderr = 1;
 618				break;
 619			}
 620			goto out;
 621		}
 622		err = EHOSTUNREACH;
 623		if (code <= NR_ICMP_UNREACH) {
 624			harderr = icmp_err_convert[code].fatal;
 625			err = icmp_err_convert[code].errno;
 626		}
 627		break;
 
 
 
 628	}
 629
 630	/*
 631	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
 632	 *	4.1.3.3.
 633	 */
 
 
 
 
 
 
 
 634	if (!inet->recverr) {
 635		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 636			goto out;
 637	} else
 638		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
 639
 640	sk->sk_err = err;
 641	sk->sk_error_report(sk);
 642out:
 643	sock_put(sk);
 644}
 645
 646void udp_err(struct sk_buff *skb, u32 info)
 647{
 648	__udp4_lib_err(skb, info, &udp_table);
 649}
 650
 651/*
 652 * Throw away all pending data and cancel the corking. Socket is locked.
 653 */
 654void udp_flush_pending_frames(struct sock *sk)
 655{
 656	struct udp_sock *up = udp_sk(sk);
 657
 658	if (up->pending) {
 659		up->len = 0;
 660		up->pending = 0;
 661		ip_flush_pending_frames(sk);
 662	}
 663}
 664EXPORT_SYMBOL(udp_flush_pending_frames);
 665
 666/**
 667 * 	udp4_hwcsum  -  handle outgoing HW checksumming
 668 * 	@skb: 	sk_buff containing the filled-in UDP header
 669 * 	        (checksum field must be zeroed out)
 670 *	@src:	source IP address
 671 *	@dst:	destination IP address
 672 */
 673static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
 674{
 675	struct udphdr *uh = udp_hdr(skb);
 676	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
 677	int offset = skb_transport_offset(skb);
 678	int len = skb->len - offset;
 679	int hlen = len;
 680	__wsum csum = 0;
 681
 682	if (!frags) {
 683		/*
 684		 * Only one fragment on the socket.
 685		 */
 686		skb->csum_start = skb_transport_header(skb) - skb->head;
 687		skb->csum_offset = offsetof(struct udphdr, check);
 688		uh->check = ~csum_tcpudp_magic(src, dst, len,
 689					       IPPROTO_UDP, 0);
 690	} else {
 
 
 691		/*
 692		 * HW-checksum won't work as there are two or more
 693		 * fragments on the socket so that all csums of sk_buffs
 694		 * should be together
 695		 */
 696		do {
 697			csum = csum_add(csum, frags->csum);
 698			hlen -= frags->len;
 699		} while ((frags = frags->next));
 700
 701		csum = skb_checksum(skb, offset, hlen, csum);
 702		skb->ip_summed = CHECKSUM_NONE;
 703
 704		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
 705		if (uh->check == 0)
 706			uh->check = CSUM_MANGLED_0;
 707	}
 708}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 709
 710static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 
 711{
 712	struct sock *sk = skb->sk;
 713	struct inet_sock *inet = inet_sk(sk);
 714	struct udphdr *uh;
 715	int err = 0;
 716	int is_udplite = IS_UDPLITE(sk);
 717	int offset = skb_transport_offset(skb);
 718	int len = skb->len - offset;
 
 719	__wsum csum = 0;
 720
 721	/*
 722	 * Create a UDP header
 723	 */
 724	uh = udp_hdr(skb);
 725	uh->source = inet->inet_sport;
 726	uh->dest = fl4->fl4_dport;
 727	uh->len = htons(len);
 728	uh->check = 0;
 729
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 730	if (is_udplite)  				 /*     UDP-Lite      */
 731		csum = udplite_csum(skb);
 732
 733	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */
 734
 735		skb->ip_summed = CHECKSUM_NONE;
 736		goto send;
 737
 738	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 
 739
 740		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
 741		goto send;
 742
 743	} else
 744		csum = udp_csum(skb);
 745
 746	/* add protocol-dependent pseudo-header */
 747	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
 748				      sk->sk_protocol, csum);
 749	if (uh->check == 0)
 750		uh->check = CSUM_MANGLED_0;
 751
 752send:
 753	err = ip_send_skb(skb);
 754	if (err) {
 755		if (err == -ENOBUFS && !inet->recverr) {
 756			UDP_INC_STATS_USER(sock_net(sk),
 757					   UDP_MIB_SNDBUFERRORS, is_udplite);
 758			err = 0;
 759		}
 760	} else
 761		UDP_INC_STATS_USER(sock_net(sk),
 762				   UDP_MIB_OUTDATAGRAMS, is_udplite);
 763	return err;
 764}
 765
 766/*
 767 * Push out all pending data as one UDP datagram. Socket is locked.
 768 */
 769static int udp_push_pending_frames(struct sock *sk)
 770{
 771	struct udp_sock  *up = udp_sk(sk);
 772	struct inet_sock *inet = inet_sk(sk);
 773	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
 774	struct sk_buff *skb;
 775	int err = 0;
 776
 777	skb = ip_finish_skb(sk, fl4);
 778	if (!skb)
 779		goto out;
 780
 781	err = udp_send_skb(skb, fl4);
 782
 783out:
 784	up->len = 0;
 785	up->pending = 0;
 786	return err;
 787}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 788
 789int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 790		size_t len)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 791{
 792	struct inet_sock *inet = inet_sk(sk);
 793	struct udp_sock *up = udp_sk(sk);
 
 794	struct flowi4 fl4_stack;
 795	struct flowi4 *fl4;
 796	int ulen = len;
 797	struct ipcm_cookie ipc;
 798	struct rtable *rt = NULL;
 799	int free = 0;
 800	int connected = 0;
 801	__be32 daddr, faddr, saddr;
 802	__be16 dport;
 803	u8  tos;
 804	int err, is_udplite = IS_UDPLITE(sk);
 805	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
 806	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 807	struct sk_buff *skb;
 808	struct ip_options_data opt_copy;
 809
 810	if (len > 0xFFFF)
 811		return -EMSGSIZE;
 812
 813	/*
 814	 *	Check the flags.
 815	 */
 816
 817	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
 818		return -EOPNOTSUPP;
 819
 820	ipc.opt = NULL;
 821	ipc.tx_flags = 0;
 822
 823	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
 824
 825	fl4 = &inet->cork.fl.u.ip4;
 826	if (up->pending) {
 827		/*
 828		 * There are pending frames.
 829		 * The socket lock must be held while it's corked.
 830		 */
 831		lock_sock(sk);
 832		if (likely(up->pending)) {
 833			if (unlikely(up->pending != AF_INET)) {
 834				release_sock(sk);
 835				return -EINVAL;
 836			}
 837			goto do_append_data;
 838		}
 839		release_sock(sk);
 840	}
 841	ulen += sizeof(struct udphdr);
 842
 843	/*
 844	 *	Get and verify the address.
 845	 */
 846	if (msg->msg_name) {
 847		struct sockaddr_in * usin = (struct sockaddr_in *)msg->msg_name;
 848		if (msg->msg_namelen < sizeof(*usin))
 849			return -EINVAL;
 850		if (usin->sin_family != AF_INET) {
 851			if (usin->sin_family != AF_UNSPEC)
 852				return -EAFNOSUPPORT;
 853		}
 854
 855		daddr = usin->sin_addr.s_addr;
 856		dport = usin->sin_port;
 857		if (dport == 0)
 858			return -EINVAL;
 859	} else {
 860		if (sk->sk_state != TCP_ESTABLISHED)
 861			return -EDESTADDRREQ;
 862		daddr = inet->inet_daddr;
 863		dport = inet->inet_dport;
 864		/* Open fast path for connected socket.
 865		   Route will not be used, if at least one option is set.
 866		 */
 867		connected = 1;
 868	}
 869	ipc.addr = inet->inet_saddr;
 870
 871	ipc.oif = sk->sk_bound_dev_if;
 872	err = sock_tx_timestamp(sk, &ipc.tx_flags);
 873	if (err)
 874		return err;
 875	if (msg->msg_controllen) {
 876		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
 877		if (err)
 
 
 
 
 878			return err;
 
 879		if (ipc.opt)
 880			free = 1;
 881		connected = 0;
 882	}
 883	if (!ipc.opt) {
 884		struct ip_options_rcu *inet_opt;
 885
 886		rcu_read_lock();
 887		inet_opt = rcu_dereference(inet->inet_opt);
 888		if (inet_opt) {
 889			memcpy(&opt_copy, inet_opt,
 890			       sizeof(*inet_opt) + inet_opt->opt.optlen);
 891			ipc.opt = &opt_copy.opt;
 892		}
 893		rcu_read_unlock();
 894	}
 895
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 896	saddr = ipc.addr;
 897	ipc.addr = faddr = daddr;
 898
 899	if (ipc.opt && ipc.opt->opt.srr) {
 900		if (!daddr)
 901			return -EINVAL;
 
 
 902		faddr = ipc.opt->opt.faddr;
 903		connected = 0;
 904	}
 905	tos = RT_TOS(inet->tos);
 906	if (sock_flag(sk, SOCK_LOCALROUTE) ||
 907	    (msg->msg_flags & MSG_DONTROUTE) ||
 908	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
 909		tos |= RTO_ONLINK;
 910		connected = 0;
 911	}
 912
 913	if (ipv4_is_multicast(daddr)) {
 914		if (!ipc.oif)
 915			ipc.oif = inet->mc_index;
 916		if (!saddr)
 917			saddr = inet->mc_addr;
 918		connected = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 919	}
 920
 921	if (connected)
 922		rt = (struct rtable *)sk_dst_check(sk, 0);
 923
 924	if (rt == NULL) {
 925		struct net *net = sock_net(sk);
 
 926
 927		fl4 = &fl4_stack;
 928		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
 
 929				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
 930				   inet_sk_flowi_flags(sk)|FLOWI_FLAG_CAN_SLEEP,
 931				   faddr, saddr, dport, inet->inet_sport);
 
 932
 933		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 934		rt = ip_route_output_flow(net, fl4, sk);
 935		if (IS_ERR(rt)) {
 936			err = PTR_ERR(rt);
 937			rt = NULL;
 938			if (err == -ENETUNREACH)
 939				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
 940			goto out;
 941		}
 942
 943		err = -EACCES;
 944		if ((rt->rt_flags & RTCF_BROADCAST) &&
 945		    !sock_flag(sk, SOCK_BROADCAST))
 946			goto out;
 947		if (connected)
 948			sk_dst_set(sk, dst_clone(&rt->dst));
 949	}
 950
 951	if (msg->msg_flags&MSG_CONFIRM)
 952		goto do_confirm;
 953back_from_confirm:
 954
 955	saddr = fl4->saddr;
 956	if (!ipc.addr)
 957		daddr = ipc.addr = fl4->daddr;
 958
 959	/* Lockless fast path for the non-corking case. */
 960	if (!corkreq) {
 961		skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
 
 
 962				  sizeof(struct udphdr), &ipc, &rt,
 963				  msg->msg_flags);
 964		err = PTR_ERR(skb);
 965		if (skb && !IS_ERR(skb))
 966			err = udp_send_skb(skb, fl4);
 967		goto out;
 968	}
 969
 970	lock_sock(sk);
 971	if (unlikely(up->pending)) {
 972		/* The socket is already corked while preparing it. */
 973		/* ... which is an evident application bug. --ANK */
 974		release_sock(sk);
 975
 976		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
 977		err = -EINVAL;
 978		goto out;
 979	}
 980	/*
 981	 *	Now cork the socket to pend data.
 982	 */
 983	fl4 = &inet->cork.fl.u.ip4;
 984	fl4->daddr = daddr;
 985	fl4->saddr = saddr;
 986	fl4->fl4_dport = dport;
 987	fl4->fl4_sport = inet->inet_sport;
 988	up->pending = AF_INET;
 989
 990do_append_data:
 991	up->len += ulen;
 992	err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
 993			     sizeof(struct udphdr), &ipc, &rt,
 994			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
 995	if (err)
 996		udp_flush_pending_frames(sk);
 997	else if (!corkreq)
 998		err = udp_push_pending_frames(sk);
 999	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1000		up->pending = 0;
1001	release_sock(sk);
1002
1003out:
1004	ip_rt_put(rt);
 
1005	if (free)
1006		kfree(ipc.opt);
1007	if (!err)
1008		return len;
1009	/*
1010	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1011	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1012	 * we don't have a good statistic (IpOutDiscards but it can be too many
1013	 * things).  We could add another new stat but at least for now that
1014	 * seems like overkill.
1015	 */
1016	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1017		UDP_INC_STATS_USER(sock_net(sk),
1018				UDP_MIB_SNDBUFERRORS, is_udplite);
1019	}
1020	return err;
1021
1022do_confirm:
1023	dst_confirm(&rt->dst);
 
1024	if (!(msg->msg_flags&MSG_PROBE) || len)
1025		goto back_from_confirm;
1026	err = 0;
1027	goto out;
1028}
1029EXPORT_SYMBOL(udp_sendmsg);
1030
1031int udp_sendpage(struct sock *sk, struct page *page, int offset,
1032		 size_t size, int flags)
1033{
1034	struct inet_sock *inet = inet_sk(sk);
1035	struct udp_sock *up = udp_sk(sk);
1036	int ret;
1037
 
 
 
1038	if (!up->pending) {
1039		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
1040
1041		/* Call udp_sendmsg to specify destination address which
1042		 * sendpage interface can't pass.
1043		 * This will succeed only when the socket is connected.
1044		 */
1045		ret = udp_sendmsg(NULL, sk, &msg, 0);
1046		if (ret < 0)
1047			return ret;
1048	}
1049
1050	lock_sock(sk);
1051
1052	if (unlikely(!up->pending)) {
1053		release_sock(sk);
1054
1055		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n");
1056		return -EINVAL;
1057	}
1058
1059	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1060			     page, offset, size, flags);
1061	if (ret == -EOPNOTSUPP) {
1062		release_sock(sk);
1063		return sock_no_sendpage(sk->sk_socket, page, offset,
1064					size, flags);
1065	}
1066	if (ret < 0) {
1067		udp_flush_pending_frames(sk);
1068		goto out;
1069	}
1070
1071	up->len += size;
1072	if (!(up->corkflag || (flags&MSG_MORE)))
1073		ret = udp_push_pending_frames(sk);
1074	if (!ret)
1075		ret = size;
1076out:
1077	release_sock(sk);
1078	return ret;
1079}
1080
 
1081
1082/**
1083 *	first_packet_length	- return length of first packet in receive queue
1084 *	@sk: socket
1085 *
1086 *	Drops all bad checksum frames, until a valid one is found.
1087 *	Returns the length of found skb, or 0 if none is found.
 
 
1088 */
1089static unsigned int first_packet_length(struct sock *sk)
1090{
1091	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
1092	struct sk_buff *skb;
1093	unsigned int res;
1094
1095	__skb_queue_head_init(&list_kill);
 
 
 
1096
1097	spin_lock_bh(&rcvq->lock);
1098	while ((skb = skb_peek(rcvq)) != NULL &&
1099		udp_lib_checksum_complete(skb)) {
1100		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1101				 IS_UDPLITE(sk));
1102		atomic_inc(&sk->sk_drops);
1103		__skb_unlink(skb, rcvq);
1104		__skb_queue_tail(&list_kill, skb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1105	}
1106	res = skb ? skb->len : 0;
1107	spin_unlock_bh(&rcvq->lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1108
1109	if (!skb_queue_empty(&list_kill)) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1110		bool slow = lock_sock_fast(sk);
1111
1112		__skb_queue_purge(&list_kill);
1113		sk_mem_reclaim_partial(sk);
1114		unlock_sock_fast(sk, slow);
1115	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1116	return res;
1117}
1118
1119/*
1120 *	IOCTL requests applicable to the UDP protocol
1121 */
1122
1123int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1124{
1125	switch (cmd) {
1126	case SIOCOUTQ:
1127	{
1128		int amount = sk_wmem_alloc_get(sk);
1129
1130		return put_user(amount, (int __user *)arg);
1131	}
1132
1133	case SIOCINQ:
1134	{
1135		unsigned int amount = first_packet_length(sk);
1136
1137		if (amount)
1138			/*
1139			 * We will only return the amount
1140			 * of this packet since that is all
1141			 * that will be read.
1142			 */
1143			amount -= sizeof(struct udphdr);
1144
1145		return put_user(amount, (int __user *)arg);
1146	}
1147
1148	default:
1149		return -ENOIOCTLCMD;
1150	}
1151
1152	return 0;
1153}
1154EXPORT_SYMBOL(udp_ioctl);
1155
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1156/*
1157 * 	This should be easy, if there is something there we
1158 * 	return it, otherwise we block.
1159 */
1160
1161int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1162		size_t len, int noblock, int flags, int *addr_len)
1163{
1164	struct inet_sock *inet = inet_sk(sk);
1165	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
1166	struct sk_buff *skb;
1167	unsigned int ulen;
1168	int peeked;
1169	int err;
1170	int is_udplite = IS_UDPLITE(sk);
1171	bool slow;
1172
1173	/*
1174	 *	Check any passed addresses
1175	 */
1176	if (addr_len)
1177		*addr_len = sizeof(*sin);
1178
1179	if (flags & MSG_ERRQUEUE)
1180		return ip_recv_error(sk, msg, len);
1181
1182try_again:
1183	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1184				  &peeked, &err);
1185	if (!skb)
1186		goto out;
1187
1188	ulen = skb->len - sizeof(struct udphdr);
1189	if (len > ulen)
1190		len = ulen;
1191	else if (len < ulen)
 
1192		msg->msg_flags |= MSG_TRUNC;
1193
1194	/*
1195	 * If checksum is needed at all, try to do it while copying the
1196	 * data.  If the data is truncated, or if we only want a partial
1197	 * coverage checksum (UDP-Lite), do it before the copy.
1198	 */
1199
1200	if (len < ulen || UDP_SKB_CB(skb)->partial_cov) {
1201		if (udp_lib_checksum_complete(skb))
 
 
 
1202			goto csum_copy_err;
1203	}
1204
1205	if (skb_csum_unnecessary(skb))
1206		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1207					      msg->msg_iov, len);
1208	else {
1209		err = skb_copy_and_csum_datagram_iovec(skb,
1210						       sizeof(struct udphdr),
1211						       msg->msg_iov);
1212
1213		if (err == -EINVAL)
1214			goto csum_copy_err;
1215	}
1216
1217	if (err)
1218		goto out_free;
 
 
 
 
 
 
 
1219
1220	if (!peeked)
1221		UDP_INC_STATS_USER(sock_net(sk),
1222				UDP_MIB_INDATAGRAMS, is_udplite);
1223
1224	sock_recv_ts_and_drops(msg, sk, skb);
1225
1226	/* Copy the address. */
1227	if (sin) {
1228		sin->sin_family = AF_INET;
1229		sin->sin_port = udp_hdr(skb)->source;
1230		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1231		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 
 
 
 
1232	}
 
 
 
 
1233	if (inet->cmsg_flags)
1234		ip_cmsg_recv(msg, skb);
1235
1236	err = len;
1237	if (flags & MSG_TRUNC)
1238		err = ulen;
1239
1240out_free:
1241	skb_free_datagram_locked(sk, skb);
1242out:
1243	return err;
1244
1245csum_copy_err:
1246	slow = lock_sock_fast(sk);
1247	if (!skb_kill_datagram(sk, skb, flags))
1248		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1249	unlock_sock_fast(sk, slow);
1250
1251	if (noblock)
1252		return -EAGAIN;
1253
1254	/* starting over for a new packet */
 
1255	msg->msg_flags &= ~MSG_TRUNC;
1256	goto try_again;
1257}
1258
 
 
 
 
 
 
 
 
 
 
 
 
1259
1260int udp_disconnect(struct sock *sk, int flags)
1261{
1262	struct inet_sock *inet = inet_sk(sk);
1263	/*
1264	 *	1003.1g - break association.
1265	 */
1266
1267	sk->sk_state = TCP_CLOSE;
1268	inet->inet_daddr = 0;
1269	inet->inet_dport = 0;
1270	sock_rps_save_rxhash(sk, 0);
1271	sk->sk_bound_dev_if = 0;
1272	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1273		inet_reset_saddr(sk);
 
 
 
 
1274
1275	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1276		sk->sk_prot->unhash(sk);
1277		inet->inet_sport = 0;
1278	}
1279	sk_dst_reset(sk);
1280	return 0;
1281}
 
 
 
 
 
 
 
 
 
1282EXPORT_SYMBOL(udp_disconnect);
1283
1284void udp_lib_unhash(struct sock *sk)
1285{
1286	if (sk_hashed(sk)) {
1287		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1288		struct udp_hslot *hslot, *hslot2;
1289
1290		hslot  = udp_hashslot(udptable, sock_net(sk),
1291				      udp_sk(sk)->udp_port_hash);
1292		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1293
1294		spin_lock_bh(&hslot->lock);
1295		if (sk_nulls_del_node_init_rcu(sk)) {
 
 
1296			hslot->count--;
1297			inet_sk(sk)->inet_num = 0;
1298			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1299
1300			spin_lock(&hslot2->lock);
1301			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1302			hslot2->count--;
1303			spin_unlock(&hslot2->lock);
1304		}
1305		spin_unlock_bh(&hslot->lock);
1306	}
1307}
1308EXPORT_SYMBOL(udp_lib_unhash);
1309
1310/*
1311 * inet_rcv_saddr was changed, we must rehash secondary hash
1312 */
1313void udp_lib_rehash(struct sock *sk, u16 newhash)
1314{
1315	if (sk_hashed(sk)) {
1316		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1317		struct udp_hslot *hslot, *hslot2, *nhslot2;
1318
1319		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1320		nhslot2 = udp_hashslot2(udptable, newhash);
1321		udp_sk(sk)->udp_portaddr_hash = newhash;
1322		if (hslot2 != nhslot2) {
 
 
1323			hslot = udp_hashslot(udptable, sock_net(sk),
1324					     udp_sk(sk)->udp_port_hash);
1325			/* we must lock primary chain too */
1326			spin_lock_bh(&hslot->lock);
 
 
1327
1328			spin_lock(&hslot2->lock);
1329			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1330			hslot2->count--;
1331			spin_unlock(&hslot2->lock);
1332
1333			spin_lock(&nhslot2->lock);
1334			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1335						 &nhslot2->head);
1336			nhslot2->count++;
1337			spin_unlock(&nhslot2->lock);
 
 
1338
1339			spin_unlock_bh(&hslot->lock);
1340		}
1341	}
1342}
1343EXPORT_SYMBOL(udp_lib_rehash);
1344
1345static void udp_v4_rehash(struct sock *sk)
1346{
1347	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1348					  inet_sk(sk)->inet_rcv_saddr,
1349					  inet_sk(sk)->inet_num);
1350	udp_lib_rehash(sk, new_hash);
1351}
1352
1353static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1354{
1355	int rc;
1356
1357	if (inet_sk(sk)->inet_daddr)
1358		sock_rps_save_rxhash(sk, skb->rxhash);
 
 
 
 
 
1359
1360	rc = ip_queue_rcv_skb(sk, skb);
1361	if (rc < 0) {
1362		int is_udplite = IS_UDPLITE(sk);
 
1363
1364		/* Note that an ENOMEM error is charged twice */
1365		if (rc == -ENOMEM)
1366			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1367					 is_udplite);
1368		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1369		kfree_skb(skb);
 
 
 
 
 
 
1370		trace_udp_fail_queue_rcv_skb(rc, sk);
1371		return -1;
1372	}
1373
1374	return 0;
1375
1376}
1377
1378/* returns:
1379 *  -1: error
1380 *   0: success
1381 *  >0: "udp encap" protocol resubmission
1382 *
1383 * Note that in the success and error cases, the skb is assumed to
1384 * have either been requeued or freed.
1385 */
1386int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1387{
 
1388	struct udp_sock *up = udp_sk(sk);
1389	int rc;
1390	int is_udplite = IS_UDPLITE(sk);
1391
1392	/*
1393	 *	Charge it to the socket, dropping if the queue is full.
1394	 */
1395	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 
1396		goto drop;
1397	nf_reset(skb);
 
 
 
 
1398
1399	if (up->encap_type) {
1400		/*
1401		 * This is an encapsulation socket so pass the skb to
1402		 * the socket's udp_encap_rcv() hook. Otherwise, just
1403		 * fall through and pass this up the UDP socket.
1404		 * up->encap_rcv() returns the following value:
1405		 * =0 if skb was successfully passed to the encap
1406		 *    handler or was discarded by it.
1407		 * >0 if skb should be passed on to UDP.
1408		 * <0 if skb should be resubmitted as proto -N
1409		 */
1410
1411		/* if we're overly short, let UDP handle it */
1412		if (skb->len > sizeof(struct udphdr) &&
1413		    up->encap_rcv != NULL) {
1414			int ret;
1415
1416			ret = (*up->encap_rcv)(sk, skb);
 
 
 
 
1417			if (ret <= 0) {
1418				UDP_INC_STATS_BH(sock_net(sk),
1419						 UDP_MIB_INDATAGRAMS,
1420						 is_udplite);
1421				return -ret;
1422			}
1423		}
1424
1425		/* FALLTHROUGH -- it's a UDP Packet */
1426	}
1427
1428	/*
1429	 * 	UDP-Lite specific tests, ignored on UDP sockets
1430	 */
1431	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
1432
1433		/*
1434		 * MIB statistics other than incrementing the error count are
1435		 * disabled for the following two types of errors: these depend
1436		 * on the application settings, not on the functioning of the
1437		 * protocol stack as such.
1438		 *
1439		 * RFC 3828 here recommends (sec 3.3): "There should also be a
1440		 * way ... to ... at least let the receiving application block
1441		 * delivery of packets with coverage values less than a value
1442		 * provided by the application."
1443		 */
1444		if (up->pcrlen == 0) {          /* full coverage was set  */
1445			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE: partial coverage "
1446				"%d while full coverage %d requested\n",
1447				UDP_SKB_CB(skb)->cscov, skb->len);
1448			goto drop;
1449		}
1450		/* The next case involves violating the min. coverage requested
1451		 * by the receiver. This is subtle: if receiver wants x and x is
1452		 * greater than the buffersize/MTU then receiver will complain
1453		 * that it wants x while sender emits packets of smaller size y.
1454		 * Therefore the above ...()->partial_cov statement is essential.
1455		 */
1456		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1457			LIMIT_NETDEBUG(KERN_WARNING
1458				"UDPLITE: coverage %d too small, need min %d\n",
1459				UDP_SKB_CB(skb)->cscov, up->pcrlen);
1460			goto drop;
1461		}
1462	}
1463
1464	if (rcu_dereference_raw(sk->sk_filter)) {
1465		if (udp_lib_checksum_complete(skb))
1466			goto drop;
1467	}
1468
1469
1470	if (sk_rcvqueues_full(sk, skb))
1471		goto drop;
1472
1473	rc = 0;
1474
1475	bh_lock_sock(sk);
1476	if (!sock_owned_by_user(sk))
1477		rc = __udp_queue_rcv_skb(sk, skb);
1478	else if (sk_add_backlog(sk, skb)) {
1479		bh_unlock_sock(sk);
1480		goto drop;
1481	}
1482	bh_unlock_sock(sk);
1483
1484	return rc;
1485
 
 
 
 
 
 
1486drop:
1487	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1488	atomic_inc(&sk->sk_drops);
1489	kfree_skb(skb);
1490	return -1;
1491}
1492
1493
1494static void flush_stack(struct sock **stack, unsigned int count,
1495			struct sk_buff *skb, unsigned int final)
1496{
1497	unsigned int i;
1498	struct sk_buff *skb1 = NULL;
1499	struct sock *sk;
1500
1501	for (i = 0; i < count; i++) {
1502		sk = stack[i];
1503		if (likely(skb1 == NULL))
1504			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
1505
1506		if (!skb1) {
1507			atomic_inc(&sk->sk_drops);
1508			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1509					 IS_UDPLITE(sk));
1510			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1511					 IS_UDPLITE(sk));
1512		}
1513
1514		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1515			skb1 = NULL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1516	}
1517	if (unlikely(skb1))
1518		kfree_skb(skb1);
1519}
 
1520
1521/*
1522 *	Multicasts and broadcasts go to each listener.
1523 *
1524 *	Note: called only from the BH handler context.
1525 */
1526static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1527				    struct udphdr  *uh,
1528				    __be32 saddr, __be32 daddr,
1529				    struct udp_table *udptable)
 
1530{
1531	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1532	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1533	int dif;
1534	unsigned int i, count = 0;
1535
1536	spin_lock(&hslot->lock);
1537	sk = sk_nulls_head(&hslot->head);
1538	dif = skb->dev->ifindex;
1539	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1540	while (sk) {
1541		stack[count++] = sk;
1542		sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1543				       daddr, uh->source, saddr, dif);
1544		if (unlikely(count == ARRAY_SIZE(stack))) {
1545			if (!sk)
1546				break;
1547			flush_stack(stack, count, skb, ~0);
1548			count = 0;
 
 
 
 
 
 
 
 
 
1549		}
1550	}
1551	/*
1552	 * before releasing chain lock, we must take a reference on sockets
1553	 */
1554	for (i = 0; i < count; i++)
1555		sock_hold(stack[i]);
1556
1557	spin_unlock(&hslot->lock);
 
 
 
 
 
 
 
 
 
 
1558
1559	/*
1560	 * do the slow work with no lock held
1561	 */
1562	if (count) {
1563		flush_stack(stack, count, skb, count - 1);
1564
1565		for (i = 0; i < count; i++)
1566			sock_put(stack[i]);
 
1567	} else {
1568		kfree_skb(skb);
 
 
1569	}
1570	return 0;
1571}
1572
1573/* Initialize UDP checksum. If exited with zero value (success),
1574 * CHECKSUM_UNNECESSARY means, that no more checks are required.
1575 * Otherwise, csum completion requires chacksumming packet body,
1576 * including udp header and folding it to skb->csum.
1577 */
1578static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
1579				 int proto)
1580{
1581	const struct iphdr *iph;
1582	int err;
1583
1584	UDP_SKB_CB(skb)->partial_cov = 0;
1585	UDP_SKB_CB(skb)->cscov = skb->len;
1586
1587	if (proto == IPPROTO_UDPLITE) {
1588		err = udplite_checksum_init(skb, uh);
1589		if (err)
1590			return err;
 
 
 
 
 
1591	}
1592
1593	iph = ip_hdr(skb);
1594	if (uh->check == 0) {
1595		skb->ip_summed = CHECKSUM_UNNECESSARY;
1596	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
1597		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1598				      proto, skb->csum))
1599			skb->ip_summed = CHECKSUM_UNNECESSARY;
1600	}
1601	if (!skb_csum_unnecessary(skb))
1602		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1603					       skb->len, proto, 0);
1604	/* Probably, we should checksum udp header (it should be in cache
1605	 * in any case) and data in tiny packets (< rx copybreak).
1606	 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1607
 
 
 
 
 
 
 
 
 
 
1608	return 0;
1609}
1610
1611/*
1612 *	All we need to do is get the socket, and then do a checksum.
1613 */
1614
1615int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1616		   int proto)
1617{
1618	struct sock *sk;
1619	struct udphdr *uh;
1620	unsigned short ulen;
1621	struct rtable *rt = skb_rtable(skb);
1622	__be32 saddr, daddr;
1623	struct net *net = dev_net(skb->dev);
 
 
 
 
1624
1625	/*
1626	 *  Validate the packet.
1627	 */
1628	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1629		goto drop;		/* No space for header. */
1630
1631	uh   = udp_hdr(skb);
1632	ulen = ntohs(uh->len);
1633	saddr = ip_hdr(skb)->saddr;
1634	daddr = ip_hdr(skb)->daddr;
1635
1636	if (ulen > skb->len)
1637		goto short_packet;
1638
1639	if (proto == IPPROTO_UDP) {
1640		/* UDP validates ulen. */
1641		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
1642			goto short_packet;
1643		uh = udp_hdr(skb);
1644	}
1645
1646	if (udp4_csum_init(skb, uh, proto))
1647		goto csum_error;
1648
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1649	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1650		return __udp4_lib_mcast_deliver(net, skb, uh,
1651				saddr, daddr, udptable);
1652
1653	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1654
1655	if (sk != NULL) {
1656		int ret = udp_queue_rcv_skb(sk, skb);
1657		sock_put(sk);
1658
1659		/* a return value > 0 means to resubmit the input, but
1660		 * it wants the return to be -protocol, or 0
1661		 */
1662		if (ret > 0)
1663			return -ret;
1664		return 0;
1665	}
1666
1667	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1668		goto drop;
1669	nf_reset(skb);
1670
1671	/* No socket. Drop packet silently, if checksum is wrong */
1672	if (udp_lib_checksum_complete(skb))
1673		goto csum_error;
1674
1675	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
 
1676	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
1677
1678	/*
1679	 * Hmm.  We got an UDP packet to a port to which we
1680	 * don't wanna listen.  Ignore it.
1681	 */
1682	kfree_skb(skb);
1683	return 0;
1684
1685short_packet:
1686	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1687		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1688		       &saddr,
1689		       ntohs(uh->source),
1690		       ulen,
1691		       skb->len,
1692		       &daddr,
1693		       ntohs(uh->dest));
1694	goto drop;
1695
1696csum_error:
1697	/*
1698	 * RFC1122: OK.  Discards the bad packet silently (as far as
1699	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
1700	 */
1701	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1702		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1703		       &saddr,
1704		       ntohs(uh->source),
1705		       &daddr,
1706		       ntohs(uh->dest),
1707		       ulen);
1708drop:
1709	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1710	kfree_skb(skb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1711	return 0;
1712}
1713
1714int udp_rcv(struct sk_buff *skb)
1715{
1716	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1717}
1718
1719void udp_destroy_sock(struct sock *sk)
1720{
 
1721	bool slow = lock_sock_fast(sk);
 
 
 
1722	udp_flush_pending_frames(sk);
1723	unlock_sock_fast(sk, slow);
 
 
 
 
 
 
 
 
 
 
1724}
1725
1726/*
1727 *	Socket option code for UDP
1728 */
1729int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1730		       char __user *optval, unsigned int optlen,
1731		       int (*push_pending_frames)(struct sock *))
1732{
1733	struct udp_sock *up = udp_sk(sk);
1734	int val;
1735	int err = 0;
1736	int is_udplite = IS_UDPLITE(sk);
1737
 
 
 
 
 
 
 
 
 
 
 
 
1738	if (optlen < sizeof(int))
1739		return -EINVAL;
1740
1741	if (get_user(val, (int __user *)optval))
1742		return -EFAULT;
1743
 
 
1744	switch (optname) {
1745	case UDP_CORK:
1746		if (val != 0) {
1747			up->corkflag = 1;
1748		} else {
1749			up->corkflag = 0;
1750			lock_sock(sk);
1751			(*push_pending_frames)(sk);
1752			release_sock(sk);
1753		}
1754		break;
1755
1756	case UDP_ENCAP:
1757		switch (val) {
1758		case 0:
 
1759		case UDP_ENCAP_ESPINUDP:
1760		case UDP_ENCAP_ESPINUDP_NON_IKE:
1761			up->encap_rcv = xfrm4_udp_encap_rcv;
1762			/* FALLTHROUGH */
 
 
 
 
 
 
1763		case UDP_ENCAP_L2TPINUDP:
1764			up->encap_type = val;
 
 
 
1765			break;
1766		default:
1767			err = -ENOPROTOOPT;
1768			break;
1769		}
1770		break;
1771
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1772	/*
1773	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
1774	 */
1775	/* The sender sets actual checksum coverage length via this option.
1776	 * The case coverage > packet length is handled by send module. */
1777	case UDPLITE_SEND_CSCOV:
1778		if (!is_udplite)         /* Disable the option on UDP sockets */
1779			return -ENOPROTOOPT;
1780		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
1781			val = 8;
1782		else if (val > USHRT_MAX)
1783			val = USHRT_MAX;
1784		up->pcslen = val;
1785		up->pcflag |= UDPLITE_SEND_CC;
1786		break;
1787
1788	/* The receiver specifies a minimum checksum coverage value. To make
1789	 * sense, this should be set to at least 8 (as done below). If zero is
1790	 * used, this again means full checksum coverage.                     */
1791	case UDPLITE_RECV_CSCOV:
1792		if (!is_udplite)         /* Disable the option on UDP sockets */
1793			return -ENOPROTOOPT;
1794		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
1795			val = 8;
1796		else if (val > USHRT_MAX)
1797			val = USHRT_MAX;
1798		up->pcrlen = val;
1799		up->pcflag |= UDPLITE_RECV_CC;
1800		break;
1801
1802	default:
1803		err = -ENOPROTOOPT;
1804		break;
1805	}
1806
1807	return err;
1808}
1809EXPORT_SYMBOL(udp_lib_setsockopt);
1810
1811int udp_setsockopt(struct sock *sk, int level, int optname,
1812		   char __user *optval, unsigned int optlen)
1813{
1814	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1815		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
 
1816					  udp_push_pending_frames);
1817	return ip_setsockopt(sk, level, optname, optval, optlen);
1818}
1819
1820#ifdef CONFIG_COMPAT
1821int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1822			  char __user *optval, unsigned int optlen)
1823{
1824	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1825		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1826					  udp_push_pending_frames);
1827	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
1828}
1829#endif
1830
1831int udp_lib_getsockopt(struct sock *sk, int level, int optname,
1832		       char __user *optval, int __user *optlen)
1833{
1834	struct udp_sock *up = udp_sk(sk);
1835	int val, len;
1836
1837	if (get_user(len, optlen))
1838		return -EFAULT;
1839
1840	len = min_t(unsigned int, len, sizeof(int));
1841
1842	if (len < 0)
1843		return -EINVAL;
1844
1845	switch (optname) {
1846	case UDP_CORK:
1847		val = up->corkflag;
1848		break;
1849
1850	case UDP_ENCAP:
1851		val = up->encap_type;
1852		break;
1853
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1854	/* The following two cannot be changed on UDP sockets, the return is
1855	 * always 0 (which corresponds to the full checksum coverage of UDP). */
1856	case UDPLITE_SEND_CSCOV:
1857		val = up->pcslen;
1858		break;
1859
1860	case UDPLITE_RECV_CSCOV:
1861		val = up->pcrlen;
1862		break;
1863
1864	default:
1865		return -ENOPROTOOPT;
1866	}
1867
1868	if (put_user(len, optlen))
1869		return -EFAULT;
1870	if (copy_to_user(optval, &val, len))
1871		return -EFAULT;
1872	return 0;
1873}
1874EXPORT_SYMBOL(udp_lib_getsockopt);
1875
1876int udp_getsockopt(struct sock *sk, int level, int optname,
1877		   char __user *optval, int __user *optlen)
1878{
1879	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1880		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1881	return ip_getsockopt(sk, level, optname, optval, optlen);
1882}
1883
1884#ifdef CONFIG_COMPAT
1885int compat_udp_getsockopt(struct sock *sk, int level, int optname,
1886				 char __user *optval, int __user *optlen)
1887{
1888	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1889		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1890	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
1891}
1892#endif
1893/**
1894 * 	udp_poll - wait for a UDP event.
1895 *	@file - file struct
1896 *	@sock - socket
1897 *	@wait - poll table
1898 *
1899 *	This is same as datagram poll, except for the special case of
1900 *	blocking sockets. If application is using a blocking fd
1901 *	and a packet with checksum error is in the queue;
1902 *	then it could get return from select indicating data available
1903 *	but then block when reading it. Add special case code
1904 *	to work around these arguably broken applications.
1905 */
1906unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
1907{
1908	unsigned int mask = datagram_poll(file, sock, wait);
1909	struct sock *sk = sock->sk;
1910
1911	/* Check for false positives due to checksum errors */
1912	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
1913	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
1914		mask &= ~(POLLIN | POLLRDNORM);
1915
 
 
 
 
 
 
 
 
1916	return mask;
1917
1918}
1919EXPORT_SYMBOL(udp_poll);
1920
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1921struct proto udp_prot = {
1922	.name		   = "UDP",
1923	.owner		   = THIS_MODULE,
1924	.close		   = udp_lib_close,
1925	.connect	   = ip4_datagram_connect,
1926	.disconnect	   = udp_disconnect,
1927	.ioctl		   = udp_ioctl,
1928	.destroy	   = udp_destroy_sock,
1929	.setsockopt	   = udp_setsockopt,
1930	.getsockopt	   = udp_getsockopt,
1931	.sendmsg	   = udp_sendmsg,
1932	.recvmsg	   = udp_recvmsg,
1933	.sendpage	   = udp_sendpage,
1934	.backlog_rcv	   = __udp_queue_rcv_skb,
1935	.hash		   = udp_lib_hash,
1936	.unhash		   = udp_lib_unhash,
1937	.rehash		   = udp_v4_rehash,
1938	.get_port	   = udp_v4_get_port,
1939	.memory_allocated  = &udp_memory_allocated,
1940	.sysctl_mem	   = sysctl_udp_mem,
1941	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1942	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1943	.obj_size	   = sizeof(struct udp_sock),
1944	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1945	.h.udp_table	   = &udp_table,
1946#ifdef CONFIG_COMPAT
1947	.compat_setsockopt = compat_udp_setsockopt,
1948	.compat_getsockopt = compat_udp_getsockopt,
1949#endif
1950	.clear_sk	   = sk_prot_clear_portaddr_nulls,
 
 
 
 
 
 
 
 
1951};
1952EXPORT_SYMBOL(udp_prot);
1953
1954/* ------------------------------------------------------------------------ */
1955#ifdef CONFIG_PROC_FS
1956
 
 
 
 
 
 
1957static struct sock *udp_get_first(struct seq_file *seq, int start)
1958{
1959	struct sock *sk;
1960	struct udp_iter_state *state = seq->private;
1961	struct net *net = seq_file_net(seq);
 
 
 
 
 
 
 
 
1962
1963	for (state->bucket = start; state->bucket <= state->udp_table->mask;
 
 
1964	     ++state->bucket) {
1965		struct hlist_nulls_node *node;
1966		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1967
1968		if (hlist_nulls_empty(&hslot->head))
1969			continue;
1970
1971		spin_lock_bh(&hslot->lock);
1972		sk_nulls_for_each(sk, node, &hslot->head) {
1973			if (!net_eq(sock_net(sk), net))
1974				continue;
1975			if (sk->sk_family == state->family)
 
1976				goto found;
1977		}
1978		spin_unlock_bh(&hslot->lock);
1979	}
1980	sk = NULL;
1981found:
1982	return sk;
1983}
1984
1985static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
1986{
1987	struct udp_iter_state *state = seq->private;
1988	struct net *net = seq_file_net(seq);
 
 
 
 
 
 
 
1989
1990	do {
1991		sk = sk_nulls_next(sk);
1992	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
 
 
1993
1994	if (!sk) {
1995		if (state->bucket <= state->udp_table->mask)
1996			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
 
 
 
1997		return udp_get_first(seq, state->bucket + 1);
1998	}
1999	return sk;
2000}
2001
2002static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2003{
2004	struct sock *sk = udp_get_first(seq, 0);
2005
2006	if (sk)
2007		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2008			--pos;
2009	return pos ? NULL : sk;
2010}
2011
2012static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2013{
2014	struct udp_iter_state *state = seq->private;
2015	state->bucket = MAX_UDP_PORTS;
2016
2017	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2018}
 
2019
2020static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2021{
2022	struct sock *sk;
2023
2024	if (v == SEQ_START_TOKEN)
2025		sk = udp_get_idx(seq, 0);
2026	else
2027		sk = udp_get_next(seq, v);
2028
2029	++*pos;
2030	return sk;
2031}
 
2032
2033static void udp_seq_stop(struct seq_file *seq, void *v)
2034{
2035	struct udp_iter_state *state = seq->private;
 
 
2036
2037	if (state->bucket <= state->udp_table->mask)
2038		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2039}
2040
2041static int udp_seq_open(struct inode *inode, struct file *file)
2042{
2043	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
2044	struct udp_iter_state *s;
2045	int err;
2046
2047	err = seq_open_net(inode, file, &afinfo->seq_ops,
2048			   sizeof(struct udp_iter_state));
2049	if (err < 0)
2050		return err;
2051
2052	s = ((struct seq_file *)file->private_data)->private;
2053	s->family		= afinfo->family;
2054	s->udp_table		= afinfo->udp_table;
2055	return err;
2056}
2057
2058/* ------------------------------------------------------------------------ */
2059int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2060{
2061	struct proc_dir_entry *p;
2062	int rc = 0;
2063
2064	afinfo->seq_fops.open		= udp_seq_open;
2065	afinfo->seq_fops.read		= seq_read;
2066	afinfo->seq_fops.llseek		= seq_lseek;
2067	afinfo->seq_fops.release	= seq_release_net;
2068
2069	afinfo->seq_ops.start		= udp_seq_start;
2070	afinfo->seq_ops.next		= udp_seq_next;
2071	afinfo->seq_ops.stop		= udp_seq_stop;
2072
2073	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2074			     &afinfo->seq_fops, afinfo);
2075	if (!p)
2076		rc = -ENOMEM;
2077	return rc;
2078}
2079EXPORT_SYMBOL(udp_proc_register);
2080
2081void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2082{
2083	proc_net_remove(net, afinfo->name);
2084}
2085EXPORT_SYMBOL(udp_proc_unregister);
2086
2087/* ------------------------------------------------------------------------ */
2088static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2089		int bucket, int *len)
2090{
2091	struct inet_sock *inet = inet_sk(sp);
2092	__be32 dest = inet->inet_daddr;
2093	__be32 src  = inet->inet_rcv_saddr;
2094	__u16 destp	  = ntohs(inet->inet_dport);
2095	__u16 srcp	  = ntohs(inet->inet_sport);
2096
2097	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2098		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
2099		bucket, src, srcp, dest, destp, sp->sk_state,
2100		sk_wmem_alloc_get(sp),
2101		sk_rmem_alloc_get(sp),
2102		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
2103		atomic_read(&sp->sk_refcnt), sp,
2104		atomic_read(&sp->sk_drops), len);
 
 
2105}
2106
2107int udp4_seq_show(struct seq_file *seq, void *v)
2108{
 
2109	if (v == SEQ_START_TOKEN)
2110		seq_printf(seq, "%-127s\n",
2111			   "  sl  local_address rem_address   st tx_queue "
2112			   "rx_queue tr tm->when retrnsmt   uid  timeout "
2113			   "inode ref pointer drops");
2114	else {
2115		struct udp_iter_state *state = seq->private;
2116		int len;
2117
2118		udp4_format_sock(v, seq, state->bucket, &len);
2119		seq_printf(seq, "%*s\n", 127 - len, "");
2120	}
 
2121	return 0;
2122}
2123
2124/* ------------------------------------------------------------------------ */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2125static struct udp_seq_afinfo udp4_seq_afinfo = {
2126	.name		= "udp",
2127	.family		= AF_INET,
2128	.udp_table	= &udp_table,
2129	.seq_fops	= {
2130		.owner	=	THIS_MODULE,
2131	},
2132	.seq_ops	= {
2133		.show		= udp4_seq_show,
2134	},
2135};
2136
2137static int __net_init udp4_proc_init_net(struct net *net)
2138{
2139	return udp_proc_register(net, &udp4_seq_afinfo);
 
 
 
2140}
2141
2142static void __net_exit udp4_proc_exit_net(struct net *net)
2143{
2144	udp_proc_unregister(net, &udp4_seq_afinfo);
2145}
2146
2147static struct pernet_operations udp4_net_ops = {
2148	.init = udp4_proc_init_net,
2149	.exit = udp4_proc_exit_net,
2150};
2151
2152int __init udp4_proc_init(void)
2153{
2154	return register_pernet_subsys(&udp4_net_ops);
2155}
2156
2157void udp4_proc_exit(void)
2158{
2159	unregister_pernet_subsys(&udp4_net_ops);
2160}
2161#endif /* CONFIG_PROC_FS */
2162
2163static __initdata unsigned long uhash_entries;
2164static int __init set_uhash_entries(char *str)
2165{
 
 
2166	if (!str)
2167		return 0;
2168	uhash_entries = simple_strtoul(str, &str, 0);
 
 
 
 
2169	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2170		uhash_entries = UDP_HTABLE_SIZE_MIN;
2171	return 1;
2172}
2173__setup("uhash_entries=", set_uhash_entries);
2174
2175void __init udp_table_init(struct udp_table *table, const char *name)
2176{
2177	unsigned int i;
2178
2179	if (!CONFIG_BASE_SMALL)
2180		table->hash = alloc_large_system_hash(name,
2181			2 * sizeof(struct udp_hslot),
2182			uhash_entries,
2183			21, /* one slot per 2 MB */
2184			0,
2185			&table->log,
2186			&table->mask,
2187			64 * 1024);
2188	/*
2189	 * Make sure hash table has the minimum size
2190	 */
2191	if (CONFIG_BASE_SMALL || table->mask < UDP_HTABLE_SIZE_MIN - 1) {
2192		table->hash = kmalloc(UDP_HTABLE_SIZE_MIN *
2193				      2 * sizeof(struct udp_hslot), GFP_KERNEL);
2194		if (!table->hash)
2195			panic(name);
2196		table->log = ilog2(UDP_HTABLE_SIZE_MIN);
2197		table->mask = UDP_HTABLE_SIZE_MIN - 1;
2198	}
2199	table->hash2 = table->hash + (table->mask + 1);
2200	for (i = 0; i <= table->mask; i++) {
2201		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
2202		table->hash[i].count = 0;
2203		spin_lock_init(&table->hash[i].lock);
2204	}
2205	for (i = 0; i <= table->mask; i++) {
2206		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
2207		table->hash2[i].count = 0;
2208		spin_lock_init(&table->hash2[i].lock);
2209	}
2210}
2211
2212void __init udp_init(void)
2213{
2214	unsigned long limit;
2215
2216	udp_table_init(&udp_table, "UDP");
2217	limit = nr_free_buffer_pages() / 8;
2218	limit = max(limit, 128UL);
2219	sysctl_udp_mem[0] = limit / 4 * 3;
2220	sysctl_udp_mem[1] = limit;
2221	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2222
2223	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2224	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2225}
 
2226
2227int udp4_ufo_send_check(struct sk_buff *skb)
2228{
2229	const struct iphdr *iph;
2230	struct udphdr *uh;
2231
2232	if (!pskb_may_pull(skb, sizeof(*uh)))
2233		return -EINVAL;
2234
2235	iph = ip_hdr(skb);
2236	uh = udp_hdr(skb);
2237
2238	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
2239				       IPPROTO_UDP, 0);
2240	skb->csum_start = skb_transport_header(skb) - skb->head;
2241	skb->csum_offset = offsetof(struct udphdr, check);
2242	skb->ip_summed = CHECKSUM_PARTIAL;
2243	return 0;
2244}
2245
2246struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, u32 features)
2247{
2248	struct sk_buff *segs = ERR_PTR(-EINVAL);
2249	unsigned int mss;
2250	int offset;
2251	__wsum csum;
2252
2253	mss = skb_shinfo(skb)->gso_size;
2254	if (unlikely(skb->len <= mss))
2255		goto out;
2256
2257	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2258		/* Packet is from an untrusted source, reset gso_segs. */
2259		int type = skb_shinfo(skb)->gso_type;
 
2260
2261		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
2262			     !(type & (SKB_GSO_UDP))))
2263			goto out;
2264
2265		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
 
 
 
2266
2267		segs = NULL;
2268		goto out;
 
2269	}
2270
2271	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
2272	 * do checksum of UDP packets sent as multiple IP fragments.
2273	 */
2274	offset = skb_checksum_start_offset(skb);
2275	csum = skb_checksum(skb, offset, skb->len - offset, 0);
2276	offset += skb->csum_offset;
2277	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
2278	skb->ip_summed = CHECKSUM_NONE;
2279
2280	/* Fragment the skb. IP headers of the fragments are updated in
2281	 * inet_gso_segment()
2282	 */
2283	segs = skb_segment(skb, features);
2284out:
2285	return segs;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2286}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2287