1/*
   2 * INET		An implementation of the TCP/IP protocol suite for the LINUX
   3 *		operating system.  INET is implemented using the  BSD Socket
   4 *		interface as the means of communication with the user level.
   5 *
   6 *		The User Datagram Protocol (UDP).
   7 *
   8 * Authors:	Ross Biro
   9 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  10 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
  11 *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
  12 *		Hirokazu Takahashi, <taka@valinux.co.jp>
  13 *
  14 * Fixes:
  15 *		Alan Cox	:	verify_area() calls
  16 *		Alan Cox	: 	stopped close while in use off icmp
  17 *					messages. Not a fix but a botch that
  18 *					for udp at least is 'valid'.
  19 *		Alan Cox	:	Fixed icmp handling properly
  20 *		Alan Cox	: 	Correct error for oversized datagrams
  21 *		Alan Cox	:	Tidied select() semantics.
  22 *		Alan Cox	:	udp_err() fixed properly, also now
  23 *					select and read wake correctly on errors
  24 *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
  25 *		Alan Cox	:	UDP can count its memory
  26 *		Alan Cox	:	send to an unknown connection causes
  27 *					an ECONNREFUSED off the icmp, but
  28 *					does NOT close.
  29 *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
  30 *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
  31 *					bug no longer crashes it.
  32 *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
  33 *		Alan Cox	:	Uses skb_free_datagram
  34 *		Alan Cox	:	Added get/set sockopt support.
  35 *		Alan Cox	:	Broadcasting without option set returns EACCES.
  36 *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
  37 *		Alan Cox	:	Use ip_tos and ip_ttl
  38 *		Alan Cox	:	SNMP Mibs
  39 *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
  40 *		Matt Dillon	:	UDP length checks.
  41 *		Alan Cox	:	Smarter af_inet used properly.
  42 *		Alan Cox	:	Use new kernel side addressing.
  43 *		Alan Cox	:	Incorrect return on truncated datagram receive.
  44 *	Arnt Gulbrandsen 	:	New udp_send and stuff
  45 *		Alan Cox	:	Cache last socket
  46 *		Alan Cox	:	Route cache
  47 *		Jon Peatfield	:	Minor efficiency fix to sendto().
  48 *		Mike Shaver	:	RFC1122 checks.
  49 *		Alan Cox	:	Nonblocking error fix.
  50 *	Willy Konynenberg	:	Transparent proxying support.
  51 *		Mike McLagan	:	Routing by source
  52 *		David S. Miller	:	New socket lookup architecture.
  53 *					Last socket cache retained as it
  54 *					does have a high hit rate.
  55 *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
  56 *		Andi Kleen	:	Some cleanups, cache destination entry
  57 *					for connect.
  58 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
  59 *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
  60 *					return ENOTCONN for unconnected sockets (POSIX)
  61 *		Janos Farkas	:	don't deliver multi/broadcasts to a different
  62 *					bound-to-device socket
  63 *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
  64 *					datagrams.
  65 *	Hirokazu Takahashi	:	sendfile() on UDP works now.
  66 *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
  67 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
  68 *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
  69 *					a single port at the same time.
  70 *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
  71 *	James Chapman		:	Add L2TP encapsulation type.
  72 *
  73 *
  74 *		This program is free software; you can redistribute it and/or
  75 *		modify it under the terms of the GNU General Public License
  76 *		as published by the Free Software Foundation; either version
  77 *		2 of the License, or (at your option) any later version.
  78 */
  79
  80#define pr_fmt(fmt) "UDP: " fmt
  81
  82#include <asm/uaccess.h>
 
  83#include <asm/ioctls.h>
  84#include <linux/bootmem.h>
  85#include <linux/highmem.h>
  86#include <linux/swap.h>
  87#include <linux/types.h>
  88#include <linux/fcntl.h>
  89#include <linux/module.h>
  90#include <linux/socket.h>
  91#include <linux/sockios.h>
  92#include <linux/igmp.h>
 
  93#include <linux/in.h>
  94#include <linux/errno.h>
  95#include <linux/timer.h>
  96#include <linux/mm.h>
  97#include <linux/inet.h>
  98#include <linux/netdevice.h>
  99#include <linux/slab.h>
 100#include <net/tcp_states.h>
 101#include <linux/skbuff.h>
 102#include <linux/proc_fs.h>
 103#include <linux/seq_file.h>
 104#include <net/net_namespace.h>
 105#include <net/icmp.h>
 
 
 106#include <net/route.h>
 107#include <net/checksum.h>
 
 108#include <net/xfrm.h>
 109#include <trace/events/udp.h>
 110#include <linux/static_key.h>
 
 
 
 111#include "udp_impl.h"
 
 
 
 
 
 
 
 112
 113struct udp_table udp_table __read_mostly;
 114EXPORT_SYMBOL(udp_table);
 115
 116long sysctl_udp_mem[3] __read_mostly;
 117EXPORT_SYMBOL(sysctl_udp_mem);
 118
 119int sysctl_udp_rmem_min __read_mostly;
 120EXPORT_SYMBOL(sysctl_udp_rmem_min);
 121
 122int sysctl_udp_wmem_min __read_mostly;
 123EXPORT_SYMBOL(sysctl_udp_wmem_min);
 124
 125atomic_long_t udp_memory_allocated;
 126EXPORT_SYMBOL(udp_memory_allocated);
 
 
 127
 128#define MAX_UDP_PORTS 65536
 129#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
 
 
 
 
 
 130
 131static int udp_lib_lport_inuse(struct net *net, __u16 num,
 132			       const struct udp_hslot *hslot,
 133			       unsigned long *bitmap,
 134			       struct sock *sk,
 135			       int (*saddr_comp)(const struct sock *sk1,
 136						 const struct sock *sk2),
 137			       unsigned int log)
 138{
 139	struct sock *sk2;
 140	struct hlist_nulls_node *node;
 141
 142	sk_nulls_for_each(sk2, node, &hslot->head)
 143		if (net_eq(sock_net(sk2), net) &&
 144		    sk2 != sk &&
 145		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
 146		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 147		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 148		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 149		    (*saddr_comp)(sk, sk2)) {
 150			if (bitmap)
 
 
 
 
 
 
 
 151				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
 152					  bitmap);
 153			else
 154				return 1;
 155		}
 
 156	return 0;
 157}
 158
 159/*
 160 * Note: we still hold spinlock of primary hash chain, so no other writer
 161 * can insert/delete a socket with local_port == num
 162 */
 163static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 164			       struct udp_hslot *hslot2,
 165			       struct sock *sk,
 166			       int (*saddr_comp)(const struct sock *sk1,
 167						 const struct sock *sk2))
 168{
 169	struct sock *sk2;
 170	struct hlist_nulls_node *node;
 171	int res = 0;
 172
 173	spin_lock(&hslot2->lock);
 174	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
 175		if (net_eq(sock_net(sk2), net) &&
 176		    sk2 != sk &&
 177		    (udp_sk(sk2)->udp_port_hash == num) &&
 178		    (!sk2->sk_reuse || !sk->sk_reuse) &&
 179		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
 180		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 181		    (*saddr_comp)(sk, sk2)) {
 182			res = 1;
 
 
 
 
 
 
 183			break;
 184		}
 
 185	spin_unlock(&hslot2->lock);
 186	return res;
 187}
 188
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 189/**
 190 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
 191 *
 192 *  @sk:          socket struct in question
 193 *  @snum:        port number to look up
 194 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
 195 *  @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
 196 *                   with NULL address
 197 */
 198int udp_lib_get_port(struct sock *sk, unsigned short snum,
 199		       int (*saddr_comp)(const struct sock *sk1,
 200					 const struct sock *sk2),
 201		     unsigned int hash2_nulladdr)
 202{
 
 203	struct udp_hslot *hslot, *hslot2;
 204	struct udp_table *udptable = sk->sk_prot->h.udp_table;
 205	int    error = 1;
 206	struct net *net = sock_net(sk);
 
 207
 208	if (!snum) {
 
 
 209		int low, high, remaining;
 210		unsigned int rand;
 211		unsigned short first, last;
 212		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
 213
 214		inet_get_local_port_range(&low, &high);
 215		remaining = (high - low) + 1;
 216
 217		rand = net_random();
 218		first = (((u64)rand * remaining) >> 32) + low;
 219		/*
 220		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
 221		 */
 222		rand = (rand | 1) * (udptable->mask + 1);
 223		last = first + udptable->mask + 1;
 224		do {
 225			hslot = udp_hashslot(udptable, net, first);
 226			bitmap_zero(bitmap, PORTS_PER_CHAIN);
 227			spin_lock_bh(&hslot->lock);
 228			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
 229					    saddr_comp, udptable->log);
 230
 231			snum = first;
 232			/*
 233			 * Iterate on all possible values of snum for this hash.
 234			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
 235			 * give us randomization and full range coverage.
 236			 */
 237			do {
 238				if (low <= snum && snum <= high &&
 239				    !test_bit(snum >> udptable->log, bitmap) &&
 240				    !inet_is_reserved_local_port(snum))
 241					goto found;
 242				snum += rand;
 243			} while (snum != first);
 244			spin_unlock_bh(&hslot->lock);
 
 245		} while (++first != last);
 246		goto fail;
 247	} else {
 248		hslot = udp_hashslot(udptable, net, snum);
 249		spin_lock_bh(&hslot->lock);
 250		if (hslot->count > 10) {
 251			int exist;
 252			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
 253
 254			slot2          &= udptable->mask;
 255			hash2_nulladdr &= udptable->mask;
 256
 257			hslot2 = udp_hashslot2(udptable, slot2);
 258			if (hslot->count < hslot2->count)
 259				goto scan_primary_hash;
 260
 261			exist = udp_lib_lport_inuse2(net, snum, hslot2,
 262						     sk, saddr_comp);
 263			if (!exist && (hash2_nulladdr != slot2)) {
 264				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
 265				exist = udp_lib_lport_inuse2(net, snum, hslot2,
 266							     sk, saddr_comp);
 267			}
 268			if (exist)
 269				goto fail_unlock;
 270			else
 271				goto found;
 272		}
 273scan_primary_hash:
 274		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
 275					saddr_comp, 0))
 276			goto fail_unlock;
 277	}
 278found:
 279	inet_sk(sk)->inet_num = snum;
 280	udp_sk(sk)->udp_port_hash = snum;
 281	udp_sk(sk)->udp_portaddr_hash ^= snum;
 282	if (sk_unhashed(sk)) {
 283		sk_nulls_add_node_rcu(sk, &hslot->head);
 
 
 
 
 
 
 
 
 284		hslot->count++;
 285		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 286
 287		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
 288		spin_lock(&hslot2->lock);
 289		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
 290					 &hslot2->head);
 
 
 
 
 
 291		hslot2->count++;
 292		spin_unlock(&hslot2->lock);
 293	}
 
 294	error = 0;
 295fail_unlock:
 296	spin_unlock_bh(&hslot->lock);
 297fail:
 298	return error;
 299}
 300EXPORT_SYMBOL(udp_lib_get_port);
 301
 302static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
 303{
 304	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
 305
 306	return 	(!ipv6_only_sock(sk2)  &&
 307		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
 308		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
 309}
 310
 311static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
 312				       unsigned int port)
 313{
 314	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
 315}
 316
 317int udp_v4_get_port(struct sock *sk, unsigned short snum)
 318{
 319	unsigned int hash2_nulladdr =
 320		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
 321	unsigned int hash2_partial =
 322		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
 323
 324	/* precompute partial secondary hash */
 325	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
 326	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
 327}
 328
 329static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 330			 unsigned short hnum,
 331			 __be16 sport, __be32 daddr, __be16 dport, int dif)
 332{
 333	int score = -1;
 334
 335	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
 336			!ipv6_only_sock(sk)) {
 337		struct inet_sock *inet = inet_sk(sk);
 338
 339		score = (sk->sk_family == PF_INET ? 1 : 0);
 340		if (inet->inet_rcv_saddr) {
 341			if (inet->inet_rcv_saddr != daddr)
 342				return -1;
 343			score += 2;
 344		}
 345		if (inet->inet_daddr) {
 346			if (inet->inet_daddr != saddr)
 347				return -1;
 348			score += 2;
 349		}
 350		if (inet->inet_dport) {
 351			if (inet->inet_dport != sport)
 352				return -1;
 353			score += 2;
 354		}
 355		if (sk->sk_bound_dev_if) {
 356			if (sk->sk_bound_dev_if != dif)
 357				return -1;
 358			score += 2;
 359		}
 360	}
 361	return score;
 362}
 363
 364/*
 365 * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
 366 */
 367#define SCORE2_MAX (1 + 2 + 2 + 2)
 368static inline int compute_score2(struct sock *sk, struct net *net,
 369				 __be32 saddr, __be16 sport,
 370				 __be32 daddr, unsigned int hnum, int dif)
 371{
 372	int score = -1;
 
 
 373
 374	if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
 375		struct inet_sock *inet = inet_sk(sk);
 
 
 376
 377		if (inet->inet_rcv_saddr != daddr)
 378			return -1;
 379		if (inet->inet_num != hnum)
 
 
 
 
 
 380			return -1;
 
 
 381
 382		score = (sk->sk_family == PF_INET ? 1 : 0);
 383		if (inet->inet_daddr) {
 384			if (inet->inet_daddr != saddr)
 385				return -1;
 386			score += 2;
 387		}
 388		if (inet->inet_dport) {
 389			if (inet->inet_dport != sport)
 390				return -1;
 391			score += 2;
 392		}
 393		if (sk->sk_bound_dev_if) {
 394			if (sk->sk_bound_dev_if != dif)
 395				return -1;
 396			score += 2;
 397		}
 398	}
 
 
 
 
 
 
 
 
 
 
 399	return score;
 400}
 401
 
 
 
 
 
 
 
 
 
 
 
 402
 403/* called with read_rcu_lock() */
 404static struct sock *udp4_lib_lookup2(struct net *net,
 405		__be32 saddr, __be16 sport,
 406		__be32 daddr, unsigned int hnum, int dif,
 407		struct udp_hslot *hslot2, unsigned int slot2)
 
 
 408{
 409	struct sock *sk, *result;
 410	struct hlist_nulls_node *node;
 411	int score, badness;
 412
 413begin:
 414	result = NULL;
 415	badness = -1;
 416	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
 417		score = compute_score2(sk, net, saddr, sport,
 418				      daddr, hnum, dif);
 419		if (score > badness) {
 420			result = sk;
 421			badness = score;
 422			if (score == SCORE2_MAX)
 423				goto exact_match;
 424		}
 425	}
 426	/*
 427	 * if the nulls value we got at the end of this lookup is
 428	 * not the expected one, we must restart lookup.
 429	 * We probably met an item that was moved to another chain.
 430	 */
 431	if (get_nulls_value(node) != slot2)
 432		goto begin;
 433
 434	if (result) {
 435exact_match:
 436		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 437			result = NULL;
 438		else if (unlikely(compute_score2(result, net, saddr, sport,
 439				  daddr, hnum, dif) < badness)) {
 440			sock_put(result);
 441			goto begin;
 
 
 
 
 442		}
 443	}
 444	return result;
 445}
 446
 447/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 448 * harder than this. -DaveM
 449 */
 450struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 451		__be16 sport, __be32 daddr, __be16 dport,
 452		int dif, struct udp_table *udptable)
 453{
 454	struct sock *sk, *result;
 455	struct hlist_nulls_node *node;
 456	unsigned short hnum = ntohs(dport);
 457	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 458	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
 459	int score, badness;
 460
 461	rcu_read_lock();
 462	if (hslot->count > 10) {
 463		hash2 = udp4_portaddr_hash(net, daddr, hnum);
 464		slot2 = hash2 & udptable->mask;
 465		hslot2 = &udptable->hash2[slot2];
 466		if (hslot->count < hslot2->count)
 467			goto begin;
 468
 469		result = udp4_lib_lookup2(net, saddr, sport,
 470					  daddr, hnum, dif,
 471					  hslot2, slot2);
 472		if (!result) {
 473			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
 474			slot2 = hash2 & udptable->mask;
 475			hslot2 = &udptable->hash2[slot2];
 476			if (hslot->count < hslot2->count)
 477				goto begin;
 478
 479			result = udp4_lib_lookup2(net, saddr, sport,
 480						  htonl(INADDR_ANY), hnum, dif,
 481						  hslot2, slot2);
 482		}
 483		rcu_read_unlock();
 484		return result;
 485	}
 486begin:
 487	result = NULL;
 488	badness = -1;
 489	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
 490		score = compute_score(sk, net, saddr, hnum, sport,
 491				      daddr, dport, dif);
 492		if (score > badness) {
 493			result = sk;
 494			badness = score;
 495		}
 496	}
 497	/*
 498	 * if the nulls value we got at the end of this lookup is
 499	 * not the expected one, we must restart lookup.
 500	 * We probably met an item that was moved to another chain.
 501	 */
 502	if (get_nulls_value(node) != slot)
 503		goto begin;
 504
 505	if (result) {
 506		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
 507			result = NULL;
 508		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
 509				  daddr, dport, dif) < badness)) {
 510			sock_put(result);
 511			goto begin;
 512		}
 513	}
 514	rcu_read_unlock();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 515	return result;
 516}
 517EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
 518
 519static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 520						 __be16 sport, __be16 dport,
 521						 struct udp_table *udptable)
 522{
 523	struct sock *sk;
 524	const struct iphdr *iph = ip_hdr(skb);
 525
 526	if (unlikely(sk = skb_steal_sock(skb)))
 527		return sk;
 528	else
 529		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
 530					 iph->daddr, dport, inet_iif(skb),
 531					 udptable);
 532}
 533
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 534struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 535			     __be32 daddr, __be16 dport, int dif)
 536{
 537	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
 
 
 
 
 
 
 538}
 539EXPORT_SYMBOL_GPL(udp4_lib_lookup);
 
 540
 541static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
 542					     __be16 loc_port, __be32 loc_addr,
 543					     __be16 rmt_port, __be32 rmt_addr,
 544					     int dif)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 545{
 546	struct hlist_nulls_node *node;
 547	struct sock *s = sk;
 548	unsigned short hnum = ntohs(loc_port);
 549
 550	sk_nulls_for_each_from(s, node) {
 551		struct inet_sock *inet = inet_sk(s);
 
 
 
 552
 553		if (!net_eq(sock_net(s), net) ||
 554		    udp_sk(s)->udp_port_hash != hnum ||
 555		    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
 556		    (inet->inet_dport != rmt_port && inet->inet_dport) ||
 557		    (inet->inet_rcv_saddr &&
 558		     inet->inet_rcv_saddr != loc_addr) ||
 559		    ipv6_only_sock(s) ||
 560		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
 561			continue;
 562		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
 
 
 
 563			continue;
 564		goto found;
 
 
 565	}
 566	s = NULL;
 567found:
 568	return s;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 569}
 570
 571/*
 572 * This routine is called by the ICMP module when it gets some
 573 * sort of error condition.  If err < 0 then the socket should
 574 * be closed and the error returned to the user.  If err > 0
 575 * it's just the icmp type << 8 | icmp code.
 576 * Header points to the ip header of the error packet. We move
 577 * on past this. Then (as it used to claim before adjustment)
 578 * header points to the first 8 bytes of the udp header.  We need
 579 * to find the appropriate port.
 580 */
 581
 582void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 583{
 584	struct inet_sock *inet;
 585	const struct iphdr *iph = (const struct iphdr *)skb->data;
 586	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
 587	const int type = icmp_hdr(skb)->type;
 588	const int code = icmp_hdr(skb)->code;
 
 589	struct sock *sk;
 590	int harderr;
 591	int err;
 592	struct net *net = dev_net(skb->dev);
 593
 594	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
 595			iph->saddr, uh->source, skb->dev->ifindex, udptable);
 596	if (sk == NULL) {
 597		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
 598		return;	/* No socket for error */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 599	}
 600
 601	err = 0;
 602	harderr = 0;
 603	inet = inet_sk(sk);
 604
 605	switch (type) {
 606	default:
 607	case ICMP_TIME_EXCEEDED:
 608		err = EHOSTUNREACH;
 609		break;
 610	case ICMP_SOURCE_QUENCH:
 611		goto out;
 612	case ICMP_PARAMETERPROB:
 613		err = EPROTO;
 614		harderr = 1;
 615		break;
 616	case ICMP_DEST_UNREACH:
 617		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
 618			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
 
 619				err = EMSGSIZE;
 620				harderr = 1;
 621				break;
 622			}
 623			goto out;
 624		}
 625		err = EHOSTUNREACH;
 626		if (code <= NR_ICMP_UNREACH) {
 627			harderr = icmp_err_convert[code].fatal;
 628			err = icmp_err_convert[code].errno;
 629		}
 630		break;
 
 
 
 631	}
 632
 633	/*
 634	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
 635	 *	4.1.3.3.
 636	 */
 637	if (!inet->recverr) {
 
 
 
 
 
 
 
 638		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 639			goto out;
 640	} else
 641		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
 642
 643	sk->sk_err = err;
 644	sk->sk_error_report(sk);
 645out:
 646	sock_put(sk);
 647}
 648
 649void udp_err(struct sk_buff *skb, u32 info)
 650{
 651	__udp4_lib_err(skb, info, &udp_table);
 652}
 653
 654/*
 655 * Throw away all pending data and cancel the corking. Socket is locked.
 656 */
 657void udp_flush_pending_frames(struct sock *sk)
 658{
 659	struct udp_sock *up = udp_sk(sk);
 660
 661	if (up->pending) {
 662		up->len = 0;
 663		up->pending = 0;
 664		ip_flush_pending_frames(sk);
 665	}
 666}
 667EXPORT_SYMBOL(udp_flush_pending_frames);
 668
 669/**
 670 * 	udp4_hwcsum  -  handle outgoing HW checksumming
 671 * 	@skb: 	sk_buff containing the filled-in UDP header
 672 * 	        (checksum field must be zeroed out)
 673 *	@src:	source IP address
 674 *	@dst:	destination IP address
 675 */
 676static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
 677{
 678	struct udphdr *uh = udp_hdr(skb);
 679	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
 680	int offset = skb_transport_offset(skb);
 681	int len = skb->len - offset;
 682	int hlen = len;
 683	__wsum csum = 0;
 684
 685	if (!frags) {
 686		/*
 687		 * Only one fragment on the socket.
 688		 */
 689		skb->csum_start = skb_transport_header(skb) - skb->head;
 690		skb->csum_offset = offsetof(struct udphdr, check);
 691		uh->check = ~csum_tcpudp_magic(src, dst, len,
 692					       IPPROTO_UDP, 0);
 693	} else {
 
 
 694		/*
 695		 * HW-checksum won't work as there are two or more
 696		 * fragments on the socket so that all csums of sk_buffs
 697		 * should be together
 698		 */
 699		do {
 700			csum = csum_add(csum, frags->csum);
 701			hlen -= frags->len;
 702		} while ((frags = frags->next));
 703
 704		csum = skb_checksum(skb, offset, hlen, csum);
 705		skb->ip_summed = CHECKSUM_NONE;
 706
 707		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
 708		if (uh->check == 0)
 709			uh->check = CSUM_MANGLED_0;
 710	}
 711}
 
 712
 713static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 714{
 715	struct sock *sk = skb->sk;
 716	struct inet_sock *inet = inet_sk(sk);
 717	struct udphdr *uh;
 718	int err = 0;
 719	int is_udplite = IS_UDPLITE(sk);
 720	int offset = skb_transport_offset(skb);
 721	int len = skb->len - offset;
 
 722	__wsum csum = 0;
 723
 724	/*
 725	 * Create a UDP header
 726	 */
 727	uh = udp_hdr(skb);
 728	uh->source = inet->inet_sport;
 729	uh->dest = fl4->fl4_dport;
 730	uh->len = htons(len);
 731	uh->check = 0;
 732
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 733	if (is_udplite)  				 /*     UDP-Lite      */
 734		csum = udplite_csum(skb);
 735
 736	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */
 737
 738		skb->ip_summed = CHECKSUM_NONE;
 739		goto send;
 740
 741	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
 
 742
 743		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
 744		goto send;
 745
 746	} else
 747		csum = udp_csum(skb);
 748
 749	/* add protocol-dependent pseudo-header */
 750	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
 751				      sk->sk_protocol, csum);
 752	if (uh->check == 0)
 753		uh->check = CSUM_MANGLED_0;
 754
 755send:
 756	err = ip_send_skb(skb);
 757	if (err) {
 758		if (err == -ENOBUFS && !inet->recverr) {
 759			UDP_INC_STATS_USER(sock_net(sk),
 760					   UDP_MIB_SNDBUFERRORS, is_udplite);
 
 761			err = 0;
 762		}
 763	} else
 764		UDP_INC_STATS_USER(sock_net(sk),
 765				   UDP_MIB_OUTDATAGRAMS, is_udplite);
 766	return err;
 767}
 768
 769/*
 770 * Push out all pending data as one UDP datagram. Socket is locked.
 771 */
 772static int udp_push_pending_frames(struct sock *sk)
 773{
 774	struct udp_sock  *up = udp_sk(sk);
 775	struct inet_sock *inet = inet_sk(sk);
 776	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
 777	struct sk_buff *skb;
 778	int err = 0;
 779
 780	skb = ip_finish_skb(sk, fl4);
 781	if (!skb)
 782		goto out;
 783
 784	err = udp_send_skb(skb, fl4);
 785
 786out:
 787	up->len = 0;
 788	up->pending = 0;
 789	return err;
 790}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 791
 792int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 793		size_t len)
 794{
 795	struct inet_sock *inet = inet_sk(sk);
 796	struct udp_sock *up = udp_sk(sk);
 
 797	struct flowi4 fl4_stack;
 798	struct flowi4 *fl4;
 799	int ulen = len;
 800	struct ipcm_cookie ipc;
 801	struct rtable *rt = NULL;
 802	int free = 0;
 803	int connected = 0;
 804	__be32 daddr, faddr, saddr;
 
 805	__be16 dport;
 806	u8  tos;
 807	int err, is_udplite = IS_UDPLITE(sk);
 808	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
 809	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
 810	struct sk_buff *skb;
 811	struct ip_options_data opt_copy;
 
 812
 813	if (len > 0xFFFF)
 814		return -EMSGSIZE;
 815
 816	/*
 817	 *	Check the flags.
 818	 */
 819
 820	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
 821		return -EOPNOTSUPP;
 822
 823	ipc.opt = NULL;
 824	ipc.tx_flags = 0;
 825
 826	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
 827
 828	fl4 = &inet->cork.fl.u.ip4;
 829	if (up->pending) {
 830		/*
 831		 * There are pending frames.
 832		 * The socket lock must be held while it's corked.
 833		 */
 834		lock_sock(sk);
 835		if (likely(up->pending)) {
 836			if (unlikely(up->pending != AF_INET)) {
 837				release_sock(sk);
 838				return -EINVAL;
 839			}
 840			goto do_append_data;
 841		}
 842		release_sock(sk);
 843	}
 844	ulen += sizeof(struct udphdr);
 845
 846	/*
 847	 *	Get and verify the address.
 848	 */
 849	if (msg->msg_name) {
 850		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
 851		if (msg->msg_namelen < sizeof(*usin))
 852			return -EINVAL;
 853		if (usin->sin_family != AF_INET) {
 854			if (usin->sin_family != AF_UNSPEC)
 855				return -EAFNOSUPPORT;
 856		}
 857
 858		daddr = usin->sin_addr.s_addr;
 859		dport = usin->sin_port;
 860		if (dport == 0)
 861			return -EINVAL;
 862	} else {
 863		if (sk->sk_state != TCP_ESTABLISHED)
 864			return -EDESTADDRREQ;
 865		daddr = inet->inet_daddr;
 866		dport = inet->inet_dport;
 867		/* Open fast path for connected socket.
 868		   Route will not be used, if at least one option is set.
 869		 */
 870		connected = 1;
 871	}
 872	ipc.addr = inet->inet_saddr;
 873
 874	ipc.oif = sk->sk_bound_dev_if;
 875	err = sock_tx_timestamp(sk, &ipc.tx_flags);
 876	if (err)
 877		return err;
 878	if (msg->msg_controllen) {
 879		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
 880		if (err)
 
 
 
 
 881			return err;
 
 882		if (ipc.opt)
 883			free = 1;
 884		connected = 0;
 885	}
 886	if (!ipc.opt) {
 887		struct ip_options_rcu *inet_opt;
 888
 889		rcu_read_lock();
 890		inet_opt = rcu_dereference(inet->inet_opt);
 891		if (inet_opt) {
 892			memcpy(&opt_copy, inet_opt,
 893			       sizeof(*inet_opt) + inet_opt->opt.optlen);
 894			ipc.opt = &opt_copy.opt;
 895		}
 896		rcu_read_unlock();
 897	}
 898
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 899	saddr = ipc.addr;
 900	ipc.addr = faddr = daddr;
 901
 902	if (ipc.opt && ipc.opt->opt.srr) {
 903		if (!daddr)
 904			return -EINVAL;
 
 
 905		faddr = ipc.opt->opt.faddr;
 906		connected = 0;
 907	}
 908	tos = RT_TOS(inet->tos);
 909	if (sock_flag(sk, SOCK_LOCALROUTE) ||
 910	    (msg->msg_flags & MSG_DONTROUTE) ||
 911	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
 912		tos |= RTO_ONLINK;
 913		connected = 0;
 914	}
 915
 
 916	if (ipv4_is_multicast(daddr)) {
 917		if (!ipc.oif)
 918			ipc.oif = inet->mc_index;
 919		if (!saddr)
 920			saddr = inet->mc_addr;
 921		connected = 0;
 922	} else if (!ipc.oif)
 923		ipc.oif = inet->uc_index;
 
 
 
 
 
 
 
 
 
 
 
 
 
 924
 925	if (connected)
 926		rt = (struct rtable *)sk_dst_check(sk, 0);
 927
 928	if (rt == NULL) {
 929		struct net *net = sock_net(sk);
 
 930
 931		fl4 = &fl4_stack;
 932		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
 933				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
 934				   inet_sk_flowi_flags(sk)|FLOWI_FLAG_CAN_SLEEP,
 935				   faddr, saddr, dport, inet->inet_sport);
 936
 937		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
 
 
 
 
 938		rt = ip_route_output_flow(net, fl4, sk);
 939		if (IS_ERR(rt)) {
 940			err = PTR_ERR(rt);
 941			rt = NULL;
 942			if (err == -ENETUNREACH)
 943				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
 944			goto out;
 945		}
 946
 947		err = -EACCES;
 948		if ((rt->rt_flags & RTCF_BROADCAST) &&
 949		    !sock_flag(sk, SOCK_BROADCAST))
 950			goto out;
 951		if (connected)
 952			sk_dst_set(sk, dst_clone(&rt->dst));
 953	}
 954
 955	if (msg->msg_flags&MSG_CONFIRM)
 956		goto do_confirm;
 957back_from_confirm:
 958
 959	saddr = fl4->saddr;
 960	if (!ipc.addr)
 961		daddr = ipc.addr = fl4->daddr;
 962
 963	/* Lockless fast path for the non-corking case. */
 964	if (!corkreq) {
 965		skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
 
 
 966				  sizeof(struct udphdr), &ipc, &rt,
 967				  msg->msg_flags);
 968		err = PTR_ERR(skb);
 969		if (skb && !IS_ERR(skb))
 970			err = udp_send_skb(skb, fl4);
 971		goto out;
 972	}
 973
 974	lock_sock(sk);
 975	if (unlikely(up->pending)) {
 976		/* The socket is already corked while preparing it. */
 977		/* ... which is an evident application bug. --ANK */
 978		release_sock(sk);
 979
 980		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("cork app bug 2\n"));
 981		err = -EINVAL;
 982		goto out;
 983	}
 984	/*
 985	 *	Now cork the socket to pend data.
 986	 */
 987	fl4 = &inet->cork.fl.u.ip4;
 988	fl4->daddr = daddr;
 989	fl4->saddr = saddr;
 990	fl4->fl4_dport = dport;
 991	fl4->fl4_sport = inet->inet_sport;
 992	up->pending = AF_INET;
 993
 994do_append_data:
 995	up->len += ulen;
 996	err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
 997			     sizeof(struct udphdr), &ipc, &rt,
 998			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
 999	if (err)
1000		udp_flush_pending_frames(sk);
1001	else if (!corkreq)
1002		err = udp_push_pending_frames(sk);
1003	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
1004		up->pending = 0;
1005	release_sock(sk);
1006
1007out:
1008	ip_rt_put(rt);
 
1009	if (free)
1010		kfree(ipc.opt);
1011	if (!err)
1012		return len;
1013	/*
1014	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
1015	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
1016	 * we don't have a good statistic (IpOutDiscards but it can be too many
1017	 * things).  We could add another new stat but at least for now that
1018	 * seems like overkill.
1019	 */
1020	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1021		UDP_INC_STATS_USER(sock_net(sk),
1022				UDP_MIB_SNDBUFERRORS, is_udplite);
1023	}
1024	return err;
1025
1026do_confirm:
1027	dst_confirm(&rt->dst);
 
1028	if (!(msg->msg_flags&MSG_PROBE) || len)
1029		goto back_from_confirm;
1030	err = 0;
1031	goto out;
1032}
1033EXPORT_SYMBOL(udp_sendmsg);
1034
1035int udp_sendpage(struct sock *sk, struct page *page, int offset,
1036		 size_t size, int flags)
1037{
1038	struct inet_sock *inet = inet_sk(sk);
1039	struct udp_sock *up = udp_sk(sk);
1040	int ret;
1041
1042	if (!up->pending) {
1043		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };
1044
1045		/* Call udp_sendmsg to specify destination address which
1046		 * sendpage interface can't pass.
1047		 * This will succeed only when the socket is connected.
1048		 */
1049		ret = udp_sendmsg(NULL, sk, &msg, 0);
1050		if (ret < 0)
1051			return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1052	}
1053
1054	lock_sock(sk);
 
1055
1056	if (unlikely(!up->pending)) {
1057		release_sock(sk);
 
1058
1059		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("udp cork app bug 3\n"));
1060		return -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1061	}
 
1062
1063	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
1064			     page, offset, size, flags);
1065	if (ret == -EOPNOTSUPP) {
1066		release_sock(sk);
1067		return sock_no_sendpage(sk->sk_socket, page, offset,
1068					size, flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1069	}
1070	if (ret < 0) {
1071		udp_flush_pending_frames(sk);
1072		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
1073	}
1074
1075	up->len += size;
1076	if (!(up->corkflag || (flags&MSG_MORE)))
1077		ret = udp_push_pending_frames(sk);
1078	if (!ret)
1079		ret = size;
1080out:
1081	release_sock(sk);
1082	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1083}
 
1084
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1085
1086/**
1087 *	first_packet_length	- return length of first packet in receive queue
1088 *	@sk: socket
1089 *
1090 *	Drops all bad checksum frames, until a valid one is found.
1091 *	Returns the length of found skb, or 0 if none is found.
1092 */
1093static unsigned int first_packet_length(struct sock *sk)
1094{
1095	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
 
1096	struct sk_buff *skb;
1097	unsigned int res;
1098
1099	__skb_queue_head_init(&list_kill);
1100
1101	spin_lock_bh(&rcvq->lock);
1102	while ((skb = skb_peek(rcvq)) != NULL &&
1103		udp_lib_checksum_complete(skb)) {
1104		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1105				 IS_UDPLITE(sk));
1106		atomic_inc(&sk->sk_drops);
1107		__skb_unlink(skb, rcvq);
1108		__skb_queue_tail(&list_kill, skb);
1109	}
1110	res = skb ? skb->len : 0;
 
 
1111	spin_unlock_bh(&rcvq->lock);
1112
1113	if (!skb_queue_empty(&list_kill)) {
1114		bool slow = lock_sock_fast(sk);
1115
1116		__skb_queue_purge(&list_kill);
1117		sk_mem_reclaim_partial(sk);
1118		unlock_sock_fast(sk, slow);
1119	}
1120	return res;
1121}
1122
1123/*
1124 *	IOCTL requests applicable to the UDP protocol
1125 */
1126
1127int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
1128{
1129	switch (cmd) {
1130	case SIOCOUTQ:
1131	{
1132		int amount = sk_wmem_alloc_get(sk);
1133
1134		return put_user(amount, (int __user *)arg);
1135	}
1136
1137	case SIOCINQ:
1138	{
1139		unsigned int amount = first_packet_length(sk);
1140
1141		if (amount)
1142			/*
1143			 * We will only return the amount
1144			 * of this packet since that is all
1145			 * that will be read.
1146			 */
1147			amount -= sizeof(struct udphdr);
1148
1149		return put_user(amount, (int __user *)arg);
1150	}
1151
1152	default:
1153		return -ENOIOCTLCMD;
1154	}
1155
1156	return 0;
1157}
1158EXPORT_SYMBOL(udp_ioctl);
1159
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1160/*
1161 * 	This should be easy, if there is something there we
1162 * 	return it, otherwise we block.
1163 */
1164
1165int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
1166		size_t len, int noblock, int flags, int *addr_len)
1167{
1168	struct inet_sock *inet = inet_sk(sk);
1169	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
1170	struct sk_buff *skb;
1171	unsigned int ulen, copied;
1172	int peeked, off = 0;
1173	int err;
1174	int is_udplite = IS_UDPLITE(sk);
1175	bool slow;
1176
1177	/*
1178	 *	Check any passed addresses
1179	 */
1180	if (addr_len)
1181		*addr_len = sizeof(*sin);
1182
1183	if (flags & MSG_ERRQUEUE)
1184		return ip_recv_error(sk, msg, len);
1185
1186try_again:
1187	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1188				  &peeked, &off, &err);
1189	if (!skb)
1190		goto out;
1191
1192	ulen = skb->len - sizeof(struct udphdr);
1193	copied = len;
1194	if (copied > ulen)
1195		copied = ulen;
1196	else if (copied < ulen)
1197		msg->msg_flags |= MSG_TRUNC;
1198
1199	/*
1200	 * If checksum is needed at all, try to do it while copying the
1201	 * data.  If the data is truncated, or if we only want a partial
1202	 * coverage checksum (UDP-Lite), do it before the copy.
1203	 */
1204
1205	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1206		if (udp_lib_checksum_complete(skb))
 
 
 
1207			goto csum_copy_err;
1208	}
1209
1210	if (skb_csum_unnecessary(skb))
1211		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1212					      msg->msg_iov, copied);
1213	else {
1214		err = skb_copy_and_csum_datagram_iovec(skb,
1215						       sizeof(struct udphdr),
1216						       msg->msg_iov);
1217
1218		if (err == -EINVAL)
1219			goto csum_copy_err;
1220	}
1221
1222	if (err)
1223		goto out_free;
 
 
 
 
 
 
 
1224
1225	if (!peeked)
1226		UDP_INC_STATS_USER(sock_net(sk),
1227				UDP_MIB_INDATAGRAMS, is_udplite);
1228
1229	sock_recv_ts_and_drops(msg, sk, skb);
1230
1231	/* Copy the address. */
1232	if (sin) {
1233		sin->sin_family = AF_INET;
1234		sin->sin_port = udp_hdr(skb)->source;
1235		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
1236		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 
 
 
 
 
1237	}
1238	if (inet->cmsg_flags)
1239		ip_cmsg_recv(msg, skb);
 
 
 
 
1240
1241	err = copied;
1242	if (flags & MSG_TRUNC)
1243		err = ulen;
1244
1245out_free:
1246	skb_free_datagram_locked(sk, skb);
1247out:
1248	return err;
1249
1250csum_copy_err:
1251	slow = lock_sock_fast(sk);
1252	if (!skb_kill_datagram(sk, skb, flags))
1253		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1254	unlock_sock_fast(sk, slow);
1255
1256	if (noblock)
1257		return -EAGAIN;
1258
1259	/* starting over for a new packet */
 
1260	msg->msg_flags &= ~MSG_TRUNC;
1261	goto try_again;
1262}
1263
 
 
 
 
 
 
 
 
1264
1265int udp_disconnect(struct sock *sk, int flags)
 
 
 
 
1266{
1267	struct inet_sock *inet = inet_sk(sk);
1268	/*
1269	 *	1003.1g - break association.
1270	 */
1271
1272	sk->sk_state = TCP_CLOSE;
1273	inet->inet_daddr = 0;
1274	inet->inet_dport = 0;
1275	sock_rps_reset_rxhash(sk);
1276	sk->sk_bound_dev_if = 0;
1277	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
1278		inet_reset_saddr(sk);
 
 
 
 
1279
1280	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
1281		sk->sk_prot->unhash(sk);
1282		inet->inet_sport = 0;
1283	}
1284	sk_dst_reset(sk);
1285	return 0;
1286}
 
 
 
 
 
 
 
 
 
1287EXPORT_SYMBOL(udp_disconnect);
1288
1289void udp_lib_unhash(struct sock *sk)
1290{
1291	if (sk_hashed(sk)) {
1292		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1293		struct udp_hslot *hslot, *hslot2;
1294
1295		hslot  = udp_hashslot(udptable, sock_net(sk),
1296				      udp_sk(sk)->udp_port_hash);
1297		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1298
1299		spin_lock_bh(&hslot->lock);
1300		if (sk_nulls_del_node_init_rcu(sk)) {
 
 
1301			hslot->count--;
1302			inet_sk(sk)->inet_num = 0;
1303			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1304
1305			spin_lock(&hslot2->lock);
1306			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1307			hslot2->count--;
1308			spin_unlock(&hslot2->lock);
1309		}
1310		spin_unlock_bh(&hslot->lock);
1311	}
1312}
1313EXPORT_SYMBOL(udp_lib_unhash);
1314
1315/*
1316 * inet_rcv_saddr was changed, we must rehash secondary hash
1317 */
1318void udp_lib_rehash(struct sock *sk, u16 newhash)
1319{
1320	if (sk_hashed(sk)) {
1321		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1322		struct udp_hslot *hslot, *hslot2, *nhslot2;
1323
1324		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1325		nhslot2 = udp_hashslot2(udptable, newhash);
1326		udp_sk(sk)->udp_portaddr_hash = newhash;
1327		if (hslot2 != nhslot2) {
 
 
1328			hslot = udp_hashslot(udptable, sock_net(sk),
1329					     udp_sk(sk)->udp_port_hash);
1330			/* we must lock primary chain too */
1331			spin_lock_bh(&hslot->lock);
 
 
1332
1333			spin_lock(&hslot2->lock);
1334			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
1335			hslot2->count--;
1336			spin_unlock(&hslot2->lock);
1337
1338			spin_lock(&nhslot2->lock);
1339			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
1340						 &nhslot2->head);
1341			nhslot2->count++;
1342			spin_unlock(&nhslot2->lock);
 
 
1343
1344			spin_unlock_bh(&hslot->lock);
1345		}
1346	}
1347}
1348EXPORT_SYMBOL(udp_lib_rehash);
1349
1350static void udp_v4_rehash(struct sock *sk)
1351{
1352	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
1353					  inet_sk(sk)->inet_rcv_saddr,
1354					  inet_sk(sk)->inet_num);
1355	udp_lib_rehash(sk, new_hash);
1356}
1357
1358static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1359{
1360	int rc;
1361
1362	if (inet_sk(sk)->inet_daddr)
1363		sock_rps_save_rxhash(sk, skb);
 
 
 
 
 
1364
1365	rc = sock_queue_rcv_skb(sk, skb);
1366	if (rc < 0) {
1367		int is_udplite = IS_UDPLITE(sk);
 
1368
1369		/* Note that an ENOMEM error is charged twice */
1370		if (rc == -ENOMEM)
1371			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1372					 is_udplite);
1373		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1374		kfree_skb(skb);
 
 
 
 
 
 
1375		trace_udp_fail_queue_rcv_skb(rc, sk);
1376		return -1;
1377	}
1378
1379	return 0;
1380
1381}
1382
1383static struct static_key udp_encap_needed __read_mostly;
1384void udp_encap_enable(void)
1385{
1386	if (!static_key_enabled(&udp_encap_needed))
1387		static_key_slow_inc(&udp_encap_needed);
1388}
1389EXPORT_SYMBOL(udp_encap_enable);
1390
1391/* returns:
1392 *  -1: error
1393 *   0: success
1394 *  >0: "udp encap" protocol resubmission
1395 *
1396 * Note that in the success and error cases, the skb is assumed to
1397 * have either been requeued or freed.
1398 */
1399int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1400{
 
1401	struct udp_sock *up = udp_sk(sk);
1402	int rc;
1403	int is_udplite = IS_UDPLITE(sk);
1404
1405	/*
1406	 *	Charge it to the socket, dropping if the queue is full.
1407	 */
1408	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
 
1409		goto drop;
1410	nf_reset(skb);
 
1411
1412	if (static_key_false(&udp_encap_needed) && up->encap_type) {
 
1413		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
1414
1415		/*
1416		 * This is an encapsulation socket so pass the skb to
1417		 * the socket's udp_encap_rcv() hook. Otherwise, just
1418		 * fall through and pass this up the UDP socket.
1419		 * up->encap_rcv() returns the following value:
1420		 * =0 if skb was successfully passed to the encap
1421		 *    handler or was discarded by it.
1422		 * >0 if skb should be passed on to UDP.
1423		 * <0 if skb should be resubmitted as proto -N
1424		 */
1425
1426		/* if we're overly short, let UDP handle it */
1427		encap_rcv = ACCESS_ONCE(up->encap_rcv);
1428		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1429			int ret;
1430
 
 
 
 
1431			ret = encap_rcv(sk, skb);
1432			if (ret <= 0) {
1433				UDP_INC_STATS_BH(sock_net(sk),
1434						 UDP_MIB_INDATAGRAMS,
1435						 is_udplite);
1436				return -ret;
1437			}
1438		}
1439
1440		/* FALLTHROUGH -- it's a UDP Packet */
1441	}
1442
1443	/*
1444	 * 	UDP-Lite specific tests, ignored on UDP sockets
1445	 */
1446	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
 
1447
1448		/*
1449		 * MIB statistics other than incrementing the error count are
1450		 * disabled for the following two types of errors: these depend
1451		 * on the application settings, not on the functioning of the
1452		 * protocol stack as such.
1453		 *
1454		 * RFC 3828 here recommends (sec 3.3): "There should also be a
1455		 * way ... to ... at least let the receiving application block
1456		 * delivery of packets with coverage values less than a value
1457		 * provided by the application."
1458		 */
1459		if (up->pcrlen == 0) {          /* full coverage was set  */
1460			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: partial coverage %d while full coverage %d requested\n",
1461				       UDP_SKB_CB(skb)->cscov, skb->len);
1462			goto drop;
1463		}
1464		/* The next case involves violating the min. coverage requested
1465		 * by the receiver. This is subtle: if receiver wants x and x is
1466		 * greater than the buffersize/MTU then receiver will complain
1467		 * that it wants x while sender emits packets of smaller size y.
1468		 * Therefore the above ...()->partial_cov statement is essential.
1469		 */
1470		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
1471			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: coverage %d too small, need min %d\n",
1472				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
1473			goto drop;
1474		}
1475	}
1476
 
1477	if (rcu_access_pointer(sk->sk_filter) &&
1478	    udp_lib_checksum_complete(skb))
1479		goto drop;
1480
1481
1482	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
1483		goto drop;
1484
1485	rc = 0;
1486
1487	ipv4_pktinfo_prepare(skb);
1488	bh_lock_sock(sk);
1489	if (!sock_owned_by_user(sk))
1490		rc = __udp_queue_rcv_skb(sk, skb);
1491	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
1492		bh_unlock_sock(sk);
1493		goto drop;
1494	}
1495	bh_unlock_sock(sk);
1496
1497	return rc;
 
 
 
1498
 
 
 
1499drop:
1500	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1501	atomic_inc(&sk->sk_drops);
1502	kfree_skb(skb);
1503	return -1;
1504}
1505
1506
1507static void flush_stack(struct sock **stack, unsigned int count,
1508			struct sk_buff *skb, unsigned int final)
1509{
1510	unsigned int i;
1511	struct sk_buff *skb1 = NULL;
1512	struct sock *sk;
1513
1514	for (i = 0; i < count; i++) {
1515		sk = stack[i];
1516		if (likely(skb1 == NULL))
1517			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
1518
1519		if (!skb1) {
1520			atomic_inc(&sk->sk_drops);
1521			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
1522					 IS_UDPLITE(sk));
1523			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
1524					 IS_UDPLITE(sk));
1525		}
 
 
 
 
 
 
1526
1527		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1528			skb1 = NULL;
 
 
 
 
 
 
 
 
 
1529	}
1530	if (unlikely(skb1))
1531		kfree_skb(skb1);
1532}
 
1533
1534/*
1535 *	Multicasts and broadcasts go to each listener.
1536 *
1537 *	Note: called only from the BH handler context.
1538 */
1539static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1540				    struct udphdr  *uh,
1541				    __be32 saddr, __be32 daddr,
1542				    struct udp_table *udptable)
 
1543{
1544	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1545	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1546	int dif;
1547	unsigned int i, count = 0;
1548
1549	spin_lock(&hslot->lock);
1550	sk = sk_nulls_head(&hslot->head);
1551	dif = skb->dev->ifindex;
1552	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1553	while (sk) {
1554		stack[count++] = sk;
1555		sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1556				       daddr, uh->source, saddr, dif);
1557		if (unlikely(count == ARRAY_SIZE(stack))) {
1558			if (!sk)
1559				break;
1560			flush_stack(stack, count, skb, ~0);
1561			count = 0;
 
 
 
 
 
 
 
 
 
1562		}
1563	}
1564	/*
1565	 * before releasing chain lock, we must take a reference on sockets
1566	 */
1567	for (i = 0; i < count; i++)
1568		sock_hold(stack[i]);
1569
1570	spin_unlock(&hslot->lock);
 
 
 
 
 
 
 
 
 
 
1571
1572	/*
1573	 * do the slow work with no lock held
1574	 */
1575	if (count) {
1576		flush_stack(stack, count, skb, count - 1);
1577
1578		for (i = 0; i < count; i++)
1579			sock_put(stack[i]);
 
1580	} else {
1581		kfree_skb(skb);
 
 
1582	}
1583	return 0;
1584}
1585
1586/* Initialize UDP checksum. If exited with zero value (success),
1587 * CHECKSUM_UNNECESSARY means, that no more checks are required.
1588 * Otherwise, csum completion requires chacksumming packet body,
1589 * including udp header and folding it to skb->csum.
1590 */
1591static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
1592				 int proto)
1593{
1594	const struct iphdr *iph;
1595	int err;
1596
1597	UDP_SKB_CB(skb)->partial_cov = 0;
1598	UDP_SKB_CB(skb)->cscov = skb->len;
1599
1600	if (proto == IPPROTO_UDPLITE) {
1601		err = udplite_checksum_init(skb, uh);
1602		if (err)
1603			return err;
 
 
 
 
 
1604	}
1605
1606	iph = ip_hdr(skb);
1607	if (uh->check == 0) {
1608		skb->ip_summed = CHECKSUM_UNNECESSARY;
1609	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
1610		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1611				      proto, skb->csum))
1612			skb->ip_summed = CHECKSUM_UNNECESSARY;
1613	}
1614	if (!skb_csum_unnecessary(skb))
1615		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1616					       skb->len, proto, 0);
1617	/* Probably, we should checksum udp header (it should be in cache
1618	 * in any case) and data in tiny packets (< rx copybreak).
1619	 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1620
1621	return 0;
1622}
1623
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1624/*
1625 *	All we need to do is get the socket, and then do a checksum.
1626 */
1627
1628int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1629		   int proto)
1630{
1631	struct sock *sk;
1632	struct udphdr *uh;
1633	unsigned short ulen;
1634	struct rtable *rt = skb_rtable(skb);
1635	__be32 saddr, daddr;
1636	struct net *net = dev_net(skb->dev);
 
 
 
 
1637
1638	/*
1639	 *  Validate the packet.
1640	 */
1641	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
1642		goto drop;		/* No space for header. */
1643
1644	uh   = udp_hdr(skb);
1645	ulen = ntohs(uh->len);
1646	saddr = ip_hdr(skb)->saddr;
1647	daddr = ip_hdr(skb)->daddr;
1648
1649	if (ulen > skb->len)
1650		goto short_packet;
1651
1652	if (proto == IPPROTO_UDP) {
1653		/* UDP validates ulen. */
1654		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
1655			goto short_packet;
1656		uh = udp_hdr(skb);
1657	}
1658
1659	if (udp4_csum_init(skb, uh, proto))
1660		goto csum_error;
1661
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1662	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1663		return __udp4_lib_mcast_deliver(net, skb, uh,
1664				saddr, daddr, udptable);
1665
1666	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1667
1668	if (sk != NULL) {
1669		int ret = udp_queue_rcv_skb(sk, skb);
1670		sock_put(sk);
1671
1672		/* a return value > 0 means to resubmit the input, but
1673		 * it wants the return to be -protocol, or 0
1674		 */
1675		if (ret > 0)
1676			return -ret;
1677		return 0;
1678	}
1679
1680	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
1681		goto drop;
1682	nf_reset(skb);
1683
1684	/* No socket. Drop packet silently, if checksum is wrong */
1685	if (udp_lib_checksum_complete(skb))
1686		goto csum_error;
1687
1688	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
 
1689	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
1690
1691	/*
1692	 * Hmm.  We got an UDP packet to a port to which we
1693	 * don't wanna listen.  Ignore it.
1694	 */
1695	kfree_skb(skb);
1696	return 0;
1697
1698short_packet:
1699	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1700		       proto == IPPROTO_UDPLITE ? "Lite" : "",
1701		       &saddr, ntohs(uh->source),
1702		       ulen, skb->len,
1703		       &daddr, ntohs(uh->dest));
 
1704	goto drop;
1705
1706csum_error:
1707	/*
1708	 * RFC1122: OK.  Discards the bad packet silently (as far as
1709	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
1710	 */
1711	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1712		       proto == IPPROTO_UDPLITE ? "Lite" : "",
1713		       &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1714		       ulen);
 
 
1715drop:
1716	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1717	kfree_skb(skb);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1718	return 0;
1719}
1720
1721int udp_rcv(struct sk_buff *skb)
1722{
1723	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1724}
1725
1726void udp_destroy_sock(struct sock *sk)
1727{
 
1728	bool slow = lock_sock_fast(sk);
 
 
 
1729	udp_flush_pending_frames(sk);
1730	unlock_sock_fast(sk, slow);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1731}
1732
1733/*
1734 *	Socket option code for UDP
1735 */
1736int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1737		       char __user *optval, unsigned int optlen,
1738		       int (*push_pending_frames)(struct sock *))
1739{
1740	struct udp_sock *up = udp_sk(sk);
1741	int val;
1742	int err = 0;
1743	int is_udplite = IS_UDPLITE(sk);
1744
 
 
 
 
 
 
 
 
 
 
 
 
1745	if (optlen < sizeof(int))
1746		return -EINVAL;
1747
1748	if (get_user(val, (int __user *)optval))
1749		return -EFAULT;
1750
 
 
1751	switch (optname) {
1752	case UDP_CORK:
1753		if (val != 0) {
1754			up->corkflag = 1;
1755		} else {
1756			up->corkflag = 0;
1757			lock_sock(sk);
1758			(*push_pending_frames)(sk);
1759			release_sock(sk);
1760		}
1761		break;
1762
1763	case UDP_ENCAP:
1764		switch (val) {
1765		case 0:
 
1766		case UDP_ENCAP_ESPINUDP:
 
 
1767		case UDP_ENCAP_ESPINUDP_NON_IKE:
1768			up->encap_rcv = xfrm4_udp_encap_rcv;
1769			/* FALLTHROUGH */
 
 
 
 
 
 
 
 
1770		case UDP_ENCAP_L2TPINUDP:
1771			up->encap_type = val;
1772			udp_encap_enable();
1773			break;
1774		default:
1775			err = -ENOPROTOOPT;
1776			break;
1777		}
1778		break;
1779
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1780	/*
1781	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
1782	 */
1783	/* The sender sets actual checksum coverage length via this option.
1784	 * The case coverage > packet length is handled by send module. */
1785	case UDPLITE_SEND_CSCOV:
1786		if (!is_udplite)         /* Disable the option on UDP sockets */
1787			return -ENOPROTOOPT;
1788		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
1789			val = 8;
1790		else if (val > USHRT_MAX)
1791			val = USHRT_MAX;
1792		up->pcslen = val;
1793		up->pcflag |= UDPLITE_SEND_CC;
1794		break;
1795
1796	/* The receiver specifies a minimum checksum coverage value. To make
1797	 * sense, this should be set to at least 8 (as done below). If zero is
1798	 * used, this again means full checksum coverage.                     */
1799	case UDPLITE_RECV_CSCOV:
1800		if (!is_udplite)         /* Disable the option on UDP sockets */
1801			return -ENOPROTOOPT;
1802		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
1803			val = 8;
1804		else if (val > USHRT_MAX)
1805			val = USHRT_MAX;
1806		up->pcrlen = val;
1807		up->pcflag |= UDPLITE_RECV_CC;
1808		break;
1809
1810	default:
1811		err = -ENOPROTOOPT;
1812		break;
1813	}
1814
1815	return err;
1816}
1817EXPORT_SYMBOL(udp_lib_setsockopt);
1818
1819int udp_setsockopt(struct sock *sk, int level, int optname,
1820		   char __user *optval, unsigned int optlen)
1821{
1822	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1823		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
 
1824					  udp_push_pending_frames);
1825	return ip_setsockopt(sk, level, optname, optval, optlen);
1826}
1827
1828#ifdef CONFIG_COMPAT
1829int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1830			  char __user *optval, unsigned int optlen)
1831{
1832	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1833		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
1834					  udp_push_pending_frames);
1835	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
1836}
1837#endif
1838
1839int udp_lib_getsockopt(struct sock *sk, int level, int optname,
1840		       char __user *optval, int __user *optlen)
1841{
1842	struct udp_sock *up = udp_sk(sk);
1843	int val, len;
1844
1845	if (get_user(len, optlen))
1846		return -EFAULT;
1847
1848	len = min_t(unsigned int, len, sizeof(int));
1849
1850	if (len < 0)
1851		return -EINVAL;
1852
1853	switch (optname) {
1854	case UDP_CORK:
1855		val = up->corkflag;
1856		break;
1857
1858	case UDP_ENCAP:
1859		val = up->encap_type;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1860		break;
1861
1862	/* The following two cannot be changed on UDP sockets, the return is
1863	 * always 0 (which corresponds to the full checksum coverage of UDP). */
1864	case UDPLITE_SEND_CSCOV:
1865		val = up->pcslen;
1866		break;
1867
1868	case UDPLITE_RECV_CSCOV:
1869		val = up->pcrlen;
1870		break;
1871
1872	default:
1873		return -ENOPROTOOPT;
1874	}
1875
1876	if (put_user(len, optlen))
1877		return -EFAULT;
1878	if (copy_to_user(optval, &val, len))
1879		return -EFAULT;
1880	return 0;
1881}
1882EXPORT_SYMBOL(udp_lib_getsockopt);
1883
1884int udp_getsockopt(struct sock *sk, int level, int optname,
1885		   char __user *optval, int __user *optlen)
1886{
1887	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1888		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1889	return ip_getsockopt(sk, level, optname, optval, optlen);
1890}
1891
1892#ifdef CONFIG_COMPAT
1893int compat_udp_getsockopt(struct sock *sk, int level, int optname,
1894				 char __user *optval, int __user *optlen)
1895{
1896	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
1897		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
1898	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
1899}
1900#endif
1901/**
1902 * 	udp_poll - wait for a UDP event.
1903 *	@file - file struct
1904 *	@sock - socket
1905 *	@wait - poll table
1906 *
1907 *	This is same as datagram poll, except for the special case of
1908 *	blocking sockets. If application is using a blocking fd
1909 *	and a packet with checksum error is in the queue;
1910 *	then it could get return from select indicating data available
1911 *	but then block when reading it. Add special case code
1912 *	to work around these arguably broken applications.
1913 */
1914unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
1915{
1916	unsigned int mask = datagram_poll(file, sock, wait);
1917	struct sock *sk = sock->sk;
1918
1919	/* Check for false positives due to checksum errors */
1920	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
1921	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
1922		mask &= ~(POLLIN | POLLRDNORM);
1923
 
 
 
 
 
 
 
 
1924	return mask;
1925
1926}
1927EXPORT_SYMBOL(udp_poll);
1928
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1929struct proto udp_prot = {
1930	.name		   = "UDP",
1931	.owner		   = THIS_MODULE,
1932	.close		   = udp_lib_close,
1933	.connect	   = ip4_datagram_connect,
1934	.disconnect	   = udp_disconnect,
1935	.ioctl		   = udp_ioctl,
1936	.destroy	   = udp_destroy_sock,
1937	.setsockopt	   = udp_setsockopt,
1938	.getsockopt	   = udp_getsockopt,
1939	.sendmsg	   = udp_sendmsg,
1940	.recvmsg	   = udp_recvmsg,
1941	.sendpage	   = udp_sendpage,
1942	.backlog_rcv	   = __udp_queue_rcv_skb,
1943	.hash		   = udp_lib_hash,
1944	.unhash		   = udp_lib_unhash,
1945	.rehash		   = udp_v4_rehash,
1946	.get_port	   = udp_v4_get_port,
1947	.memory_allocated  = &udp_memory_allocated,
1948	.sysctl_mem	   = sysctl_udp_mem,
1949	.sysctl_wmem	   = &sysctl_udp_wmem_min,
1950	.sysctl_rmem	   = &sysctl_udp_rmem_min,
1951	.obj_size	   = sizeof(struct udp_sock),
1952	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1953	.h.udp_table	   = &udp_table,
1954#ifdef CONFIG_COMPAT
1955	.compat_setsockopt = compat_udp_setsockopt,
1956	.compat_getsockopt = compat_udp_getsockopt,
1957#endif
1958	.clear_sk	   = sk_prot_clear_portaddr_nulls,
 
 
 
 
 
 
 
 
1959};
1960EXPORT_SYMBOL(udp_prot);
1961
1962/* ------------------------------------------------------------------------ */
1963#ifdef CONFIG_PROC_FS
1964
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1965static struct sock *udp_get_first(struct seq_file *seq, int start)
1966{
1967	struct sock *sk;
1968	struct udp_iter_state *state = seq->private;
1969	struct net *net = seq_file_net(seq);
 
 
1970
1971	for (state->bucket = start; state->bucket <= state->udp_table->mask;
 
 
1972	     ++state->bucket) {
1973		struct hlist_nulls_node *node;
1974		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1975
1976		if (hlist_nulls_empty(&hslot->head))
1977			continue;
1978
1979		spin_lock_bh(&hslot->lock);
1980		sk_nulls_for_each(sk, node, &hslot->head) {
1981			if (!net_eq(sock_net(sk), net))
1982				continue;
1983			if (sk->sk_family == state->family)
1984				goto found;
1985		}
1986		spin_unlock_bh(&hslot->lock);
1987	}
1988	sk = NULL;
1989found:
1990	return sk;
1991}
1992
1993static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
1994{
1995	struct udp_iter_state *state = seq->private;
1996	struct net *net = seq_file_net(seq);
 
1997
1998	do {
1999		sk = sk_nulls_next(sk);
2000	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
2001
2002	if (!sk) {
2003		if (state->bucket <= state->udp_table->mask)
2004			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
 
 
 
2005		return udp_get_first(seq, state->bucket + 1);
2006	}
2007	return sk;
2008}
2009
2010static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
2011{
2012	struct sock *sk = udp_get_first(seq, 0);
2013
2014	if (sk)
2015		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
2016			--pos;
2017	return pos ? NULL : sk;
2018}
2019
2020static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
2021{
2022	struct udp_iter_state *state = seq->private;
2023	state->bucket = MAX_UDP_PORTS;
2024
2025	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
2026}
 
2027
2028static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2029{
2030	struct sock *sk;
2031
2032	if (v == SEQ_START_TOKEN)
2033		sk = udp_get_idx(seq, 0);
2034	else
2035		sk = udp_get_next(seq, v);
2036
2037	++*pos;
2038	return sk;
2039}
 
2040
2041static void udp_seq_stop(struct seq_file *seq, void *v)
2042{
2043	struct udp_iter_state *state = seq->private;
 
2044
2045	if (state->bucket <= state->udp_table->mask)
2046		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2047}
2048
2049int udp_seq_open(struct inode *inode, struct file *file)
2050{
2051	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
2052	struct udp_iter_state *s;
2053	int err;
2054
2055	err = seq_open_net(inode, file, &afinfo->seq_ops,
2056			   sizeof(struct udp_iter_state));
2057	if (err < 0)
2058		return err;
2059
2060	s = ((struct seq_file *)file->private_data)->private;
2061	s->family		= afinfo->family;
2062	s->udp_table		= afinfo->udp_table;
2063	return err;
2064}
2065EXPORT_SYMBOL(udp_seq_open);
2066
2067/* ------------------------------------------------------------------------ */
2068int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
2069{
2070	struct proc_dir_entry *p;
2071	int rc = 0;
2072
2073	afinfo->seq_ops.start		= udp_seq_start;
2074	afinfo->seq_ops.next		= udp_seq_next;
2075	afinfo->seq_ops.stop		= udp_seq_stop;
2076
2077	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2078			     afinfo->seq_fops, afinfo);
2079	if (!p)
2080		rc = -ENOMEM;
2081	return rc;
2082}
2083EXPORT_SYMBOL(udp_proc_register);
2084
2085void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
2086{
2087	proc_net_remove(net, afinfo->name);
2088}
2089EXPORT_SYMBOL(udp_proc_unregister);
2090
2091/* ------------------------------------------------------------------------ */
2092static void udp4_format_sock(struct sock *sp, struct seq_file *f,
2093		int bucket, int *len)
2094{
2095	struct inet_sock *inet = inet_sk(sp);
2096	__be32 dest = inet->inet_daddr;
2097	__be32 src  = inet->inet_rcv_saddr;
2098	__u16 destp	  = ntohs(inet->inet_dport);
2099	__u16 srcp	  = ntohs(inet->inet_sport);
2100
2101	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
2102		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
2103		bucket, src, srcp, dest, destp, sp->sk_state,
2104		sk_wmem_alloc_get(sp),
2105		sk_rmem_alloc_get(sp),
2106		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
2107		atomic_read(&sp->sk_refcnt), sp,
2108		atomic_read(&sp->sk_drops), len);
 
 
2109}
2110
2111int udp4_seq_show(struct seq_file *seq, void *v)
2112{
 
2113	if (v == SEQ_START_TOKEN)
2114		seq_printf(seq, "%-127s\n",
2115			   "  sl  local_address rem_address   st tx_queue "
2116			   "rx_queue tr tm->when retrnsmt   uid  timeout "
2117			   "inode ref pointer drops");
2118	else {
2119		struct udp_iter_state *state = seq->private;
2120		int len;
2121
2122		udp4_format_sock(v, seq, state->bucket, &len);
2123		seq_printf(seq, "%*s\n", 127 - len, "");
2124	}
 
2125	return 0;
2126}
2127
2128static const struct file_operations udp_afinfo_seq_fops = {
2129	.owner    = THIS_MODULE,
2130	.open     = udp_seq_open,
2131	.read     = seq_read,
2132	.llseek   = seq_lseek,
2133	.release  = seq_release_net
2134};
2135
2136/* ------------------------------------------------------------------------ */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2137static struct udp_seq_afinfo udp4_seq_afinfo = {
2138	.name		= "udp",
2139	.family		= AF_INET,
2140	.udp_table	= &udp_table,
2141	.seq_fops	= &udp_afinfo_seq_fops,
2142	.seq_ops	= {
2143		.show		= udp4_seq_show,
2144	},
2145};
2146
2147static int __net_init udp4_proc_init_net(struct net *net)
2148{
2149	return udp_proc_register(net, &udp4_seq_afinfo);
 
 
 
2150}
2151
2152static void __net_exit udp4_proc_exit_net(struct net *net)
2153{
2154	udp_proc_unregister(net, &udp4_seq_afinfo);
2155}
2156
2157static struct pernet_operations udp4_net_ops = {
2158	.init = udp4_proc_init_net,
2159	.exit = udp4_proc_exit_net,
2160};
2161
2162int __init udp4_proc_init(void)
2163{
2164	return register_pernet_subsys(&udp4_net_ops);
2165}
2166
2167void udp4_proc_exit(void)
2168{
2169	unregister_pernet_subsys(&udp4_net_ops);
2170}
2171#endif /* CONFIG_PROC_FS */
2172
2173static __initdata unsigned long uhash_entries;
2174static int __init set_uhash_entries(char *str)
2175{
2176	ssize_t ret;
2177
2178	if (!str)
2179		return 0;
2180
2181	ret = kstrtoul(str, 0, &uhash_entries);
2182	if (ret)
2183		return 0;
2184
2185	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
2186		uhash_entries = UDP_HTABLE_SIZE_MIN;
2187	return 1;
2188}
2189__setup("uhash_entries=", set_uhash_entries);
2190
2191void __init udp_table_init(struct udp_table *table, const char *name)
2192{
2193	unsigned int i;
2194
2195	table->hash = alloc_large_system_hash(name,
2196					      2 * sizeof(struct udp_hslot),
2197					      uhash_entries,
2198					      21, /* one slot per 2 MB */
2199					      0,
2200					      &table->log,
2201					      &table->mask,
2202					      UDP_HTABLE_SIZE_MIN,
2203					      64 * 1024);
2204
2205	table->hash2 = table->hash + (table->mask + 1);
2206	for (i = 0; i <= table->mask; i++) {
2207		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
2208		table->hash[i].count = 0;
2209		spin_lock_init(&table->hash[i].lock);
2210	}
2211	for (i = 0; i <= table->mask; i++) {
2212		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
2213		table->hash2[i].count = 0;
2214		spin_lock_init(&table->hash2[i].lock);
2215	}
2216}
2217
2218void __init udp_init(void)
2219{
2220	unsigned long limit;
2221
2222	udp_table_init(&udp_table, "UDP");
2223	limit = nr_free_buffer_pages() / 8;
2224	limit = max(limit, 128UL);
2225	sysctl_udp_mem[0] = limit / 4 * 3;
2226	sysctl_udp_mem[1] = limit;
2227	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
2228
2229	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
2230	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
2231}
 
2232
2233int udp4_ufo_send_check(struct sk_buff *skb)
2234{
2235	const struct iphdr *iph;
2236	struct udphdr *uh;
2237
2238	if (!pskb_may_pull(skb, sizeof(*uh)))
2239		return -EINVAL;
2240
2241	iph = ip_hdr(skb);
2242	uh = udp_hdr(skb);
2243
2244	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
2245				       IPPROTO_UDP, 0);
2246	skb->csum_start = skb_transport_header(skb) - skb->head;
2247	skb->csum_offset = offsetof(struct udphdr, check);
2248	skb->ip_summed = CHECKSUM_PARTIAL;
2249	return 0;
2250}
2251
2252struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
2253	netdev_features_t features)
2254{
2255	struct sk_buff *segs = ERR_PTR(-EINVAL);
2256	unsigned int mss;
2257	int offset;
2258	__wsum csum;
2259
2260	mss = skb_shinfo(skb)->gso_size;
2261	if (unlikely(skb->len <= mss))
2262		goto out;
2263
2264	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
2265		/* Packet is from an untrusted source, reset gso_segs. */
2266		int type = skb_shinfo(skb)->gso_type;
 
2267
2268		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
2269			     !(type & (SKB_GSO_UDP))))
2270			goto out;
2271
2272		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
 
 
 
2273
2274		segs = NULL;
2275		goto out;
 
2276	}
2277
2278	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
2279	 * do checksum of UDP packets sent as multiple IP fragments.
2280	 */
2281	offset = skb_checksum_start_offset(skb);
2282	csum = skb_checksum(skb, offset, skb->len - offset, 0);
2283	offset += skb->csum_offset;
2284	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
2285	skb->ip_summed = CHECKSUM_NONE;
2286
2287	/* Fragment the skb. IP headers of the fragments are updated in
2288	 * inet_gso_segment()
2289	 */
2290	segs = skb_segment(skb, features);
2291out:
2292	return segs;
 
 
 
 
 
 
 
 
 
 
 
2293}
2294