udp.c 50.0 KB
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/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		The User Datagram Protocol (UDP).
 *
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 * Authors:	Ross Biro
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 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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 *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
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 *		Hirokazu Takahashi, <taka@valinux.co.jp>
 *
 * Fixes:
 *		Alan Cox	:	verify_area() calls
 *		Alan Cox	: 	stopped close while in use off icmp
 *					messages. Not a fix but a botch that
 *					for udp at least is 'valid'.
 *		Alan Cox	:	Fixed icmp handling properly
 *		Alan Cox	: 	Correct error for oversized datagrams
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 *		Alan Cox	:	Tidied select() semantics.
 *		Alan Cox	:	udp_err() fixed properly, also now
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 *					select and read wake correctly on errors
 *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
 *		Alan Cox	:	UDP can count its memory
 *		Alan Cox	:	send to an unknown connection causes
 *					an ECONNREFUSED off the icmp, but
 *					does NOT close.
 *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
 *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
 *					bug no longer crashes it.
 *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
 *		Alan Cox	:	Uses skb_free_datagram
 *		Alan Cox	:	Added get/set sockopt support.
 *		Alan Cox	:	Broadcasting without option set returns EACCES.
 *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
 *		Alan Cox	:	Use ip_tos and ip_ttl
 *		Alan Cox	:	SNMP Mibs
 *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
 *		Matt Dillon	:	UDP length checks.
 *		Alan Cox	:	Smarter af_inet used properly.
 *		Alan Cox	:	Use new kernel side addressing.
 *		Alan Cox	:	Incorrect return on truncated datagram receive.
 *	Arnt Gulbrandsen 	:	New udp_send and stuff
 *		Alan Cox	:	Cache last socket
 *		Alan Cox	:	Route cache
 *		Jon Peatfield	:	Minor efficiency fix to sendto().
 *		Mike Shaver	:	RFC1122 checks.
 *		Alan Cox	:	Nonblocking error fix.
 *	Willy Konynenberg	:	Transparent proxying support.
 *		Mike McLagan	:	Routing by source
 *		David S. Miller	:	New socket lookup architecture.
 *					Last socket cache retained as it
 *					does have a high hit rate.
 *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
 *		Andi Kleen	:	Some cleanups, cache destination entry
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 *					for connect.
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 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
 *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
 *					return ENOTCONN for unconnected sockets (POSIX)
 *		Janos Farkas	:	don't deliver multi/broadcasts to a different
 *					bound-to-device socket
 *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
 *					datagrams.
 *	Hirokazu Takahashi	:	sendfile() on UDP works now.
 *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
 *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
 *					a single port at the same time.
 *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
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 *	James Chapman		:	Add L2TP encapsulation type.
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 *
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
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#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
#include <linux/swap.h>
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#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
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#include <linux/igmp.h>
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#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
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#include <net/tcp_states.h>
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#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
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#include <net/net_namespace.h>
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#include <net/icmp.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
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#include "udp_impl.h"
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struct udp_table udp_table __read_mostly;
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EXPORT_SYMBOL(udp_table);
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int sysctl_udp_mem[3] __read_mostly;
EXPORT_SYMBOL(sysctl_udp_mem);
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int sysctl_udp_rmem_min __read_mostly;
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EXPORT_SYMBOL(sysctl_udp_rmem_min);
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int sysctl_udp_wmem_min __read_mostly;
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EXPORT_SYMBOL(sysctl_udp_wmem_min);

atomic_t udp_memory_allocated;
EXPORT_SYMBOL(udp_memory_allocated);

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#define MAX_UDP_PORTS 65536
#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
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static int udp_lib_lport_inuse(struct net *net, __u16 num,
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			       const struct udp_hslot *hslot,
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			       unsigned long *bitmap,
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			       struct sock *sk,
			       int (*saddr_comp)(const struct sock *sk1,
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						 const struct sock *sk2),
			       unsigned int log)
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{
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	struct sock *sk2;
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	struct hlist_nulls_node *node;
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	sk_nulls_for_each(sk2, node, &hslot->head)
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		if (net_eq(sock_net(sk2), net)			&&
		    sk2 != sk					&&
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		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
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		    (!sk2->sk_reuse || !sk->sk_reuse)		&&
		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
			|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
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		    (*saddr_comp)(sk, sk2)) {
			if (bitmap)
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				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
					  bitmap);
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			else
				return 1;
		}
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	return 0;
}

/**
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 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
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 *
 *  @sk:          socket struct in question
 *  @snum:        port number to look up
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 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
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 */
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int udp_lib_get_port(struct sock *sk, unsigned short snum,
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		       int (*saddr_comp)(const struct sock *sk1,
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					 const struct sock *sk2))
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{
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	struct udp_hslot *hslot, *hslot2;
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	struct udp_table *udptable = sk->sk_prot->h.udp_table;
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	int    error = 1;
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	struct net *net = sock_net(sk);
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	if (!snum) {
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		int low, high, remaining;
		unsigned rand;
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		unsigned short first, last;
		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
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		inet_get_local_port_range(&low, &high);
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		remaining = (high - low) + 1;
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		rand = net_random();
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		first = (((u64)rand * remaining) >> 32) + low;
		/*
		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
		 */
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		rand = (rand | 1) * (udptable->mask + 1);
		for (last = first + udptable->mask + 1;
		     first != last;
		     first++) {
			hslot = udp_hashslot(udptable, net, first);
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			bitmap_zero(bitmap, PORTS_PER_CHAIN);
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			spin_lock_bh(&hslot->lock);
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			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
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					    saddr_comp, udptable->log);
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			snum = first;
			/*
			 * Iterate on all possible values of snum for this hash.
			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
			 * give us randomization and full range coverage.
			 */
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			do {
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				if (low <= snum && snum <= high &&
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				    !test_bit(snum >> udptable->log, bitmap))
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					goto found;
				snum += rand;
			} while (snum != first);
			spin_unlock_bh(&hslot->lock);
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		}
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		goto fail;
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	} else {
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		hslot = udp_hashslot(udptable, net, snum);
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		spin_lock_bh(&hslot->lock);
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		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
					saddr_comp, 0))
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			goto fail_unlock;
	}
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found:
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	inet_sk(sk)->inet_num = snum;
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	udp_sk(sk)->udp_port_hash = snum;
	udp_sk(sk)->udp_portaddr_hash ^= snum;
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	if (sk_unhashed(sk)) {
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		sk_nulls_add_node_rcu(sk, &hslot->head);
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		hslot->count++;
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		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
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		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
		spin_lock(&hslot2->lock);
		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
					 &hslot2->head);
		hslot2->count++;
		spin_unlock(&hslot2->lock);
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	}
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	error = 0;
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fail_unlock:
	spin_unlock_bh(&hslot->lock);
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fail:
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	return error;
}
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EXPORT_SYMBOL(udp_lib_get_port);
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static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
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{
	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);

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	return 	(!ipv6_only_sock(sk2)  &&
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		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
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}

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static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
				       unsigned int port)
{
	return jhash_1word(saddr, net_hash_mix(net)) ^ port;
}

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int udp_v4_get_port(struct sock *sk, unsigned short snum)
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{
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	/* precompute partial secondary hash */
	udp_sk(sk)->udp_portaddr_hash =
		udp4_portaddr_hash(sock_net(sk),
				   inet_sk(sk)->inet_rcv_saddr,
				   0);
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	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal);
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}

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static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
			 unsigned short hnum,
			 __be16 sport, __be32 daddr, __be16 dport, int dif)
{
	int score = -1;

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	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
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			!ipv6_only_sock(sk)) {
		struct inet_sock *inet = inet_sk(sk);

		score = (sk->sk_family == PF_INET ? 1 : 0);
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		if (inet->inet_rcv_saddr) {
			if (inet->inet_rcv_saddr != daddr)
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				return -1;
			score += 2;
		}
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		if (inet->inet_daddr) {
			if (inet->inet_daddr != saddr)
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				return -1;
			score += 2;
		}
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		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
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				return -1;
			score += 2;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score += 2;
		}
	}
	return score;
}

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/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 * harder than this. -DaveM
 */
static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
		__be16 sport, __be32 daddr, __be16 dport,
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		int dif, struct udp_table *udptable)
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{
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	struct sock *sk, *result;
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	struct hlist_nulls_node *node;
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	unsigned short hnum = ntohs(dport);
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	unsigned int hash = udp_hashfn(net, hnum, udptable->mask);
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	struct udp_hslot *hslot = &udptable->hash[hash];
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	int score, badness;
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	rcu_read_lock();
begin:
	result = NULL;
	badness = -1;
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	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
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		score = compute_score(sk, net, saddr, hnum, sport,
				      daddr, dport, dif);
		if (score > badness) {
			result = sk;
			badness = score;
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		}
	}
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	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
	if (get_nulls_value(node) != hash)
		goto begin;

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	if (result) {
		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
			result = NULL;
		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
				  daddr, dport, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	rcu_read_unlock();
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	return result;
}

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static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
						 __be16 sport, __be16 dport,
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						 struct udp_table *udptable)
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{
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	struct sock *sk;
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	const struct iphdr *iph = ip_hdr(skb);

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	if (unlikely(sk = skb_steal_sock(skb)))
		return sk;
	else
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		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
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					 iph->daddr, dport, inet_iif(skb),
					 udptable);
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}

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struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
			     __be32 daddr, __be16 dport, int dif)
{
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	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
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}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);

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static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
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					     __be16 loc_port, __be32 loc_addr,
					     __be16 rmt_port, __be32 rmt_addr,
					     int dif)
{
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	struct hlist_nulls_node *node;
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	struct sock *s = sk;
	unsigned short hnum = ntohs(loc_port);

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	sk_nulls_for_each_from(s, node) {
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		struct inet_sock *inet = inet_sk(s);

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		if (!net_eq(sock_net(s), net)				||
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		    udp_sk(s)->udp_port_hash != hnum			||
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		    (inet->inet_daddr && inet->inet_daddr != rmt_addr)	||
		    (inet->inet_dport != rmt_port && inet->inet_dport)	||
		    (inet->inet_rcv_saddr	&&
		     inet->inet_rcv_saddr != loc_addr)			||
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		    ipv6_only_sock(s)					||
		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
			continue;
		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
			continue;
		goto found;
	}
	s = NULL;
found:
	return s;
}

/*
 * This routine is called by the ICMP module when it gets some
 * sort of error condition.  If err < 0 then the socket should
 * be closed and the error returned to the user.  If err > 0
 * it's just the icmp type << 8 | icmp code.
 * Header points to the ip header of the error packet. We move
 * on past this. Then (as it used to claim before adjustment)
 * header points to the first 8 bytes of the udp header.  We need
 * to find the appropriate port.
 */

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void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
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{
	struct inet_sock *inet;
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	struct iphdr *iph = (struct iphdr *)skb->data;
	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
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	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	struct sock *sk;
	int harderr;
	int err;
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	struct net *net = dev_net(skb->dev);
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	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
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			iph->saddr, uh->source, skb->dev->ifindex, udptable);
	if (sk == NULL) {
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		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
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		return;	/* No socket for error */
	}

	err = 0;
	harderr = 0;
	inet = inet_sk(sk);

	switch (type) {
	default:
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	case ICMP_SOURCE_QUENCH:
		goto out;
	case ICMP_PARAMETERPROB:
		err = EPROTO;
		harderr = 1;
		break;
	case ICMP_DEST_UNREACH:
		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
				err = EMSGSIZE;
				harderr = 1;
				break;
			}
			goto out;
		}
		err = EHOSTUNREACH;
		if (code <= NR_ICMP_UNREACH) {
			harderr = icmp_err_convert[code].fatal;
			err = icmp_err_convert[code].errno;
		}
		break;
	}

	/*
	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
	 *	4.1.3.3.
	 */
	if (!inet->recverr) {
		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
			goto out;
	} else {
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		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
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	}
	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

void udp_err(struct sk_buff *skb, u32 info)
{
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	__udp4_lib_err(skb, info, &udp_table);
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}

/*
 * Throw away all pending data and cancel the corking. Socket is locked.
 */
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void udp_flush_pending_frames(struct sock *sk)
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{
	struct udp_sock *up = udp_sk(sk);

	if (up->pending) {
		up->len = 0;
		up->pending = 0;
		ip_flush_pending_frames(sk);
	}
}
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EXPORT_SYMBOL(udp_flush_pending_frames);
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/**
 * 	udp4_hwcsum_outgoing  -  handle outgoing HW checksumming
 * 	@sk: 	socket we are sending on
 * 	@skb: 	sk_buff containing the filled-in UDP header
 * 	        (checksum field must be zeroed out)
 */
static void udp4_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
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				 __be32 src, __be32 dst, int len)
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{
	unsigned int offset;
	struct udphdr *uh = udp_hdr(skb);
	__wsum csum = 0;

	if (skb_queue_len(&sk->sk_write_queue) == 1) {
		/*
		 * Only one fragment on the socket.
		 */
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
		uh->check = ~csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, 0);
	} else {
		/*
		 * HW-checksum won't work as there are two or more
		 * fragments on the socket so that all csums of sk_buffs
		 * should be together
		 */
		offset = skb_transport_offset(skb);
		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);

		skb->ip_summed = CHECKSUM_NONE;

		skb_queue_walk(&sk->sk_write_queue, skb) {
			csum = csum_add(csum, skb->csum);
		}

		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
		if (uh->check == 0)
			uh->check = CSUM_MANGLED_0;
	}
}

/*
 * Push out all pending data as one UDP datagram. Socket is locked.
 */
static int udp_push_pending_frames(struct sock *sk)
{
	struct udp_sock  *up = udp_sk(sk);
	struct inet_sock *inet = inet_sk(sk);
	struct flowi *fl = &inet->cork.fl;
	struct sk_buff *skb;
	struct udphdr *uh;
	int err = 0;
	int is_udplite = IS_UDPLITE(sk);
	__wsum csum = 0;

	/* Grab the skbuff where UDP header space exists. */
	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
		goto out;

	/*
	 * Create a UDP header
	 */
	uh = udp_hdr(skb);
	uh->source = fl->fl_ip_sport;
	uh->dest = fl->fl_ip_dport;
	uh->len = htons(up->len);
	uh->check = 0;

	if (is_udplite)  				 /*     UDP-Lite      */
		csum  = udplite_csum_outgoing(sk, skb);

	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */

		skb->ip_summed = CHECKSUM_NONE;
		goto send;

	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */

E
Eric Dumazet 已提交
576
		udp4_hwcsum_outgoing(sk, skb, fl->fl4_src, fl->fl4_dst, up->len);
577 578 579 580 581 582 583
		goto send;

	} else						 /*   `normal' UDP    */
		csum = udp_csum_outgoing(sk, skb);

	/* add protocol-dependent pseudo-header */
	uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst, up->len,
E
Eric Dumazet 已提交
584
				      sk->sk_protocol, csum);
585 586 587 588 589
	if (uh->check == 0)
		uh->check = CSUM_MANGLED_0;

send:
	err = ip_push_pending_frames(sk);
E
Eric Dumazet 已提交
590 591 592 593 594 595 596 597 598
	if (err) {
		if (err == -ENOBUFS && !inet->recverr) {
			UDP_INC_STATS_USER(sock_net(sk),
					   UDP_MIB_SNDBUFERRORS, is_udplite);
			err = 0;
		}
	} else
		UDP_INC_STATS_USER(sock_net(sk),
				   UDP_MIB_OUTDATAGRAMS, is_udplite);
599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628
out:
	up->len = 0;
	up->pending = 0;
	return err;
}

int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct udp_sock *up = udp_sk(sk);
	int ulen = len;
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	int free = 0;
	int connected = 0;
	__be32 daddr, faddr, saddr;
	__be16 dport;
	u8  tos;
	int err, is_udplite = IS_UDPLITE(sk);
	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);

	if (len > 0xFFFF)
		return -EMSGSIZE;

	/*
	 *	Check the flags.
	 */

E
Eric Dumazet 已提交
629
	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
630 631 632
		return -EOPNOTSUPP;

	ipc.opt = NULL;
633
	ipc.shtx.flags = 0;
634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655

	if (up->pending) {
		/*
		 * There are pending frames.
		 * The socket lock must be held while it's corked.
		 */
		lock_sock(sk);
		if (likely(up->pending)) {
			if (unlikely(up->pending != AF_INET)) {
				release_sock(sk);
				return -EINVAL;
			}
			goto do_append_data;
		}
		release_sock(sk);
	}
	ulen += sizeof(struct udphdr);

	/*
	 *	Get and verify the address.
	 */
	if (msg->msg_name) {
E
Eric Dumazet 已提交
656
		struct sockaddr_in * usin = (struct sockaddr_in *)msg->msg_name;
657 658 659 660 661 662 663 664 665 666 667 668 669 670
		if (msg->msg_namelen < sizeof(*usin))
			return -EINVAL;
		if (usin->sin_family != AF_INET) {
			if (usin->sin_family != AF_UNSPEC)
				return -EAFNOSUPPORT;
		}

		daddr = usin->sin_addr.s_addr;
		dport = usin->sin_port;
		if (dport == 0)
			return -EINVAL;
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;
E
Eric Dumazet 已提交
671 672
		daddr = inet->inet_daddr;
		dport = inet->inet_dport;
673 674 675 676 677
		/* Open fast path for connected socket.
		   Route will not be used, if at least one option is set.
		 */
		connected = 1;
	}
E
Eric Dumazet 已提交
678
	ipc.addr = inet->inet_saddr;
679 680

	ipc.oif = sk->sk_bound_dev_if;
681 682 683
	err = sock_tx_timestamp(msg, sk, &ipc.shtx);
	if (err)
		return err;
684
	if (msg->msg_controllen) {
685
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720
		if (err)
			return err;
		if (ipc.opt)
			free = 1;
		connected = 0;
	}
	if (!ipc.opt)
		ipc.opt = inet->opt;

	saddr = ipc.addr;
	ipc.addr = faddr = daddr;

	if (ipc.opt && ipc.opt->srr) {
		if (!daddr)
			return -EINVAL;
		faddr = ipc.opt->faddr;
		connected = 0;
	}
	tos = RT_TOS(inet->tos);
	if (sock_flag(sk, SOCK_LOCALROUTE) ||
	    (msg->msg_flags & MSG_DONTROUTE) ||
	    (ipc.opt && ipc.opt->is_strictroute)) {
		tos |= RTO_ONLINK;
		connected = 0;
	}

	if (ipv4_is_multicast(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
		connected = 0;
	}

	if (connected)
E
Eric Dumazet 已提交
721
		rt = (struct rtable *)sk_dst_check(sk, 0);
722 723 724

	if (rt == NULL) {
		struct flowi fl = { .oif = ipc.oif,
725
				    .mark = sk->sk_mark,
726 727 728 729 730
				    .nl_u = { .ip4_u =
					      { .daddr = faddr,
						.saddr = saddr,
						.tos = tos } },
				    .proto = sk->sk_protocol,
731
				    .flags = inet_sk_flowi_flags(sk),
732
				    .uli_u = { .ports =
E
Eric Dumazet 已提交
733
					       { .sport = inet->inet_sport,
734
						 .dport = dport } } };
735 736
		struct net *net = sock_net(sk);

737
		security_sk_classify_flow(sk, &fl);
738
		err = ip_route_output_flow(net, &rt, &fl, sk, 1);
739 740
		if (err) {
			if (err == -ENETUNREACH)
741
				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776
			goto out;
		}

		err = -EACCES;
		if ((rt->rt_flags & RTCF_BROADCAST) &&
		    !sock_flag(sk, SOCK_BROADCAST))
			goto out;
		if (connected)
			sk_dst_set(sk, dst_clone(&rt->u.dst));
	}

	if (msg->msg_flags&MSG_CONFIRM)
		goto do_confirm;
back_from_confirm:

	saddr = rt->rt_src;
	if (!ipc.addr)
		daddr = ipc.addr = rt->rt_dst;

	lock_sock(sk);
	if (unlikely(up->pending)) {
		/* The socket is already corked while preparing it. */
		/* ... which is an evident application bug. --ANK */
		release_sock(sk);

		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
		err = -EINVAL;
		goto out;
	}
	/*
	 *	Now cork the socket to pend data.
	 */
	inet->cork.fl.fl4_dst = daddr;
	inet->cork.fl.fl_ip_dport = dport;
	inet->cork.fl.fl4_src = saddr;
E
Eric Dumazet 已提交
777
	inet->cork.fl.fl_ip_sport = inet->inet_sport;
778 779 780 781 782 783
	up->pending = AF_INET;

do_append_data:
	up->len += ulen;
	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
	err = ip_append_data(sk, getfrag, msg->msg_iov, ulen,
784
			sizeof(struct udphdr), &ipc, &rt,
785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807
			corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
	if (err)
		udp_flush_pending_frames(sk);
	else if (!corkreq)
		err = udp_push_pending_frames(sk);
	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
		up->pending = 0;
	release_sock(sk);

out:
	ip_rt_put(rt);
	if (free)
		kfree(ipc.opt);
	if (!err)
		return len;
	/*
	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
	 * we don't have a good statistic (IpOutDiscards but it can be too many
	 * things).  We could add another new stat but at least for now that
	 * seems like overkill.
	 */
	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
808 809
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_SNDBUFERRORS, is_udplite);
810 811 812 813 814 815 816 817 818 819
	}
	return err;

do_confirm:
	dst_confirm(&rt->u.dst);
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}
E
Eric Dumazet 已提交
820
EXPORT_SYMBOL(udp_sendmsg);
821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869

int udp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
{
	struct udp_sock *up = udp_sk(sk);
	int ret;

	if (!up->pending) {
		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };

		/* Call udp_sendmsg to specify destination address which
		 * sendpage interface can't pass.
		 * This will succeed only when the socket is connected.
		 */
		ret = udp_sendmsg(NULL, sk, &msg, 0);
		if (ret < 0)
			return ret;
	}

	lock_sock(sk);

	if (unlikely(!up->pending)) {
		release_sock(sk);

		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n");
		return -EINVAL;
	}

	ret = ip_append_page(sk, page, offset, size, flags);
	if (ret == -EOPNOTSUPP) {
		release_sock(sk);
		return sock_no_sendpage(sk->sk_socket, page, offset,
					size, flags);
	}
	if (ret < 0) {
		udp_flush_pending_frames(sk);
		goto out;
	}

	up->len += size;
	if (!(up->corkflag || (flags&MSG_MORE)))
		ret = udp_push_pending_frames(sk);
	if (!ret)
		ret = size;
out:
	release_sock(sk);
	return ret;
}

E
Eric Dumazet 已提交
870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890

/**
 *	first_packet_length	- return length of first packet in receive queue
 *	@sk: socket
 *
 *	Drops all bad checksum frames, until a valid one is found.
 *	Returns the length of found skb, or 0 if none is found.
 */
static unsigned int first_packet_length(struct sock *sk)
{
	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
	struct sk_buff *skb;
	unsigned int res;

	__skb_queue_head_init(&list_kill);

	spin_lock_bh(&rcvq->lock);
	while ((skb = skb_peek(rcvq)) != NULL &&
		udp_lib_checksum_complete(skb)) {
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
				 IS_UDPLITE(sk));
E
Eric Dumazet 已提交
891
		atomic_inc(&sk->sk_drops);
E
Eric Dumazet 已提交
892 893 894 895 896 897 898 899 900 901 902 903 904 905 906
		__skb_unlink(skb, rcvq);
		__skb_queue_tail(&list_kill, skb);
	}
	res = skb ? skb->len : 0;
	spin_unlock_bh(&rcvq->lock);

	if (!skb_queue_empty(&list_kill)) {
		lock_sock(sk);
		__skb_queue_purge(&list_kill);
		sk_mem_reclaim_partial(sk);
		release_sock(sk);
	}
	return res;
}

L
Linus Torvalds 已提交
907 908 909
/*
 *	IOCTL requests applicable to the UDP protocol
 */
910

L
Linus Torvalds 已提交
911 912
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
913 914
	switch (cmd) {
	case SIOCOUTQ:
L
Linus Torvalds 已提交
915
	{
916 917
		int amount = sk_wmem_alloc_get(sk);

918 919
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
920

921 922
	case SIOCINQ:
	{
E
Eric Dumazet 已提交
923
		unsigned int amount = first_packet_length(sk);
924

E
Eric Dumazet 已提交
925
		if (amount)
926 927 928 929 930
			/*
			 * We will only return the amount
			 * of this packet since that is all
			 * that will be read.
			 */
E
Eric Dumazet 已提交
931 932
			amount -= sizeof(struct udphdr);

933 934
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
935

936 937
	default:
		return -ENOIOCTLCMD;
L
Linus Torvalds 已提交
938
	}
939 940

	return 0;
L
Linus Torvalds 已提交
941
}
E
Eric Dumazet 已提交
942
EXPORT_SYMBOL(udp_ioctl);
L
Linus Torvalds 已提交
943

944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963
/*
 * 	This should be easy, if there is something there we
 * 	return it, otherwise we block.
 */

int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
	struct sk_buff *skb;
	unsigned int ulen, copied;
	int peeked;
	int err;
	int is_udplite = IS_UDPLITE(sk);

	/*
	 *	Check any passed addresses
	 */
	if (addr_len)
E
Eric Dumazet 已提交
964
		*addr_len = sizeof(*sin);
965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994

	if (flags & MSG_ERRQUEUE)
		return ip_recv_error(sk, msg, len);

try_again:
	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
				  &peeked, &err);
	if (!skb)
		goto out;

	ulen = skb->len - sizeof(struct udphdr);
	copied = len;
	if (copied > ulen)
		copied = ulen;
	else if (copied < ulen)
		msg->msg_flags |= MSG_TRUNC;

	/*
	 * If checksum is needed at all, try to do it while copying the
	 * data.  If the data is truncated, or if we only want a partial
	 * coverage checksum (UDP-Lite), do it before the copy.
	 */

	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
		if (udp_lib_checksum_complete(skb))
			goto csum_copy_err;
	}

	if (skb_csum_unnecessary(skb))
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
E
Eric Dumazet 已提交
995
					      msg->msg_iov, copied);
996
	else {
E
Eric Dumazet 已提交
997 998 999
		err = skb_copy_and_csum_datagram_iovec(skb,
						       sizeof(struct udphdr),
						       msg->msg_iov);
1000 1001 1002 1003 1004 1005 1006 1007 1008

		if (err == -EINVAL)
			goto csum_copy_err;
	}

	if (err)
		goto out_free;

	if (!peeked)
1009 1010
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_INDATAGRAMS, is_udplite);
1011

1012
	sock_recv_ts_and_drops(msg, sk, skb);
1013 1014

	/* Copy the address. */
E
Eric Dumazet 已提交
1015
	if (sin) {
1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028
		sin->sin_family = AF_INET;
		sin->sin_port = udp_hdr(skb)->source;
		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
	}
	if (inet->cmsg_flags)
		ip_cmsg_recv(msg, skb);

	err = copied;
	if (flags & MSG_TRUNC)
		err = ulen;

out_free:
1029
	skb_free_datagram_locked(sk, skb);
1030 1031 1032 1033 1034 1035
out:
	return err;

csum_copy_err:
	lock_sock(sk);
	if (!skb_kill_datagram(sk, skb, flags))
1036
		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1037 1038 1039 1040 1041 1042 1043 1044
	release_sock(sk);

	if (noblock)
		return -EAGAIN;
	goto try_again;
}


L
Linus Torvalds 已提交
1045 1046 1047 1048 1049 1050
int udp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
	/*
	 *	1003.1g - break association.
	 */
1051

L
Linus Torvalds 已提交
1052
	sk->sk_state = TCP_CLOSE;
E
Eric Dumazet 已提交
1053 1054
	inet->inet_daddr = 0;
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
1055 1056 1057 1058 1059 1060
	sk->sk_bound_dev_if = 0;
	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
		sk->sk_prot->unhash(sk);
E
Eric Dumazet 已提交
1061
		inet->inet_sport = 0;
L
Linus Torvalds 已提交
1062 1063 1064 1065
	}
	sk_dst_reset(sk);
	return 0;
}
E
Eric Dumazet 已提交
1066
EXPORT_SYMBOL(udp_disconnect);
L
Linus Torvalds 已提交
1067

1068 1069
void udp_lib_unhash(struct sock *sk)
{
1070 1071
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1072 1073 1074 1075 1076
		struct udp_hslot *hslot, *hslot2;

		hslot  = udp_hashslot(udptable, sock_net(sk),
				      udp_sk(sk)->udp_port_hash);
		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1077

1078 1079
		spin_lock_bh(&hslot->lock);
		if (sk_nulls_del_node_init_rcu(sk)) {
E
Eric Dumazet 已提交
1080
			hslot->count--;
E
Eric Dumazet 已提交
1081
			inet_sk(sk)->inet_num = 0;
1082
			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1083 1084 1085 1086 1087

			spin_lock(&hslot2->lock);
			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
			hslot2->count--;
			spin_unlock(&hslot2->lock);
1088 1089
		}
		spin_unlock_bh(&hslot->lock);
1090 1091 1092 1093
	}
}
EXPORT_SYMBOL(udp_lib_unhash);

H
Herbert Xu 已提交
1094 1095
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
1096 1097 1098 1099
	int rc = sock_queue_rcv_skb(sk, skb);

	if (rc < 0) {
		int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
1100 1101

		/* Note that an ENOMEM error is charged twice */
E
Eric Dumazet 已提交
1102
		if (rc == -ENOMEM)
H
Herbert Xu 已提交
1103 1104
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 is_udplite);
E
Eric Dumazet 已提交
1105 1106 1107
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
		kfree_skb(skb);
		return -1;
H
Herbert Xu 已提交
1108 1109 1110 1111 1112 1113
	}

	return 0;

}

1114 1115 1116 1117 1118 1119 1120 1121
/* returns:
 *  -1: error
 *   0: success
 *  >0: "udp encap" protocol resubmission
 *
 * Note that in the success and error cases, the skb is assumed to
 * have either been requeued or freed.
 */
E
Eric Dumazet 已提交
1122
int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153
{
	struct udp_sock *up = udp_sk(sk);
	int rc;
	int is_udplite = IS_UDPLITE(sk);

	/*
	 *	Charge it to the socket, dropping if the queue is full.
	 */
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto drop;
	nf_reset(skb);

	if (up->encap_type) {
		/*
		 * This is an encapsulation socket so pass the skb to
		 * the socket's udp_encap_rcv() hook. Otherwise, just
		 * fall through and pass this up the UDP socket.
		 * up->encap_rcv() returns the following value:
		 * =0 if skb was successfully passed to the encap
		 *    handler or was discarded by it.
		 * >0 if skb should be passed on to UDP.
		 * <0 if skb should be resubmitted as proto -N
		 */

		/* if we're overly short, let UDP handle it */
		if (skb->len > sizeof(struct udphdr) &&
		    up->encap_rcv != NULL) {
			int ret;

			ret = (*up->encap_rcv)(sk, skb);
			if (ret <= 0) {
1154 1155
				UDP_INC_STATS_BH(sock_net(sk),
						 UDP_MIB_INDATAGRAMS,
1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204
						 is_udplite);
				return -ret;
			}
		}

		/* FALLTHROUGH -- it's a UDP Packet */
	}

	/*
	 * 	UDP-Lite specific tests, ignored on UDP sockets
	 */
	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {

		/*
		 * MIB statistics other than incrementing the error count are
		 * disabled for the following two types of errors: these depend
		 * on the application settings, not on the functioning of the
		 * protocol stack as such.
		 *
		 * RFC 3828 here recommends (sec 3.3): "There should also be a
		 * way ... to ... at least let the receiving application block
		 * delivery of packets with coverage values less than a value
		 * provided by the application."
		 */
		if (up->pcrlen == 0) {          /* full coverage was set  */
			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE: partial coverage "
				"%d while full coverage %d requested\n",
				UDP_SKB_CB(skb)->cscov, skb->len);
			goto drop;
		}
		/* The next case involves violating the min. coverage requested
		 * by the receiver. This is subtle: if receiver wants x and x is
		 * greater than the buffersize/MTU then receiver will complain
		 * that it wants x while sender emits packets of smaller size y.
		 * Therefore the above ...()->partial_cov statement is essential.
		 */
		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
			LIMIT_NETDEBUG(KERN_WARNING
				"UDPLITE: coverage %d too small, need min %d\n",
				UDP_SKB_CB(skb)->cscov, up->pcrlen);
			goto drop;
		}
	}

	if (sk->sk_filter) {
		if (udp_lib_checksum_complete(skb))
			goto drop;
	}

H
Herbert Xu 已提交
1205
	rc = 0;
1206

H
Herbert Xu 已提交
1207 1208 1209 1210 1211 1212 1213 1214
	bh_lock_sock(sk);
	if (!sock_owned_by_user(sk))
		rc = __udp_queue_rcv_skb(sk, skb);
	else
		sk_add_backlog(sk, skb);
	bh_unlock_sock(sk);

	return rc;
1215 1216

drop:
1217
	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
E
Eric Dumazet 已提交
1218
	atomic_inc(&sk->sk_drops);
1219 1220 1221 1222 1223 1224 1225 1226 1227 1228
	kfree_skb(skb);
	return -1;
}

/*
 *	Multicasts and broadcasts go to each listener.
 *
 *	Note: called only from the BH handler context,
 *	so we don't need to lock the hashes.
 */
1229
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1230 1231
				    struct udphdr  *uh,
				    __be32 saddr, __be32 daddr,
1232
				    struct udp_table *udptable)
1233 1234
{
	struct sock *sk;
1235
	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1236 1237
	int dif;

1238
	spin_lock(&hslot->lock);
1239
	sk = sk_nulls_head(&hslot->head);
1240
	dif = skb->dev->ifindex;
1241
	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1242 1243 1244 1245 1246 1247
	if (sk) {
		struct sock *sknext = NULL;

		do {
			struct sk_buff *skb1 = skb;

1248
			sknext = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1249 1250
						   daddr, uh->source, saddr,
						   dif);
1251 1252 1253 1254
			if (sknext)
				skb1 = skb_clone(skb, GFP_ATOMIC);

			if (skb1) {
H
Herbert Xu 已提交
1255
				int ret = udp_queue_rcv_skb(sk, skb1);
1256 1257 1258 1259 1260 1261 1262 1263
				if (ret > 0)
					/* we should probably re-process instead
					 * of dropping packets here. */
					kfree_skb(skb1);
			}
			sk = sknext;
		} while (sknext);
	} else
1264
		consume_skb(skb);
1265
	spin_unlock(&hslot->lock);
1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292
	return 0;
}

/* Initialize UDP checksum. If exited with zero value (success),
 * CHECKSUM_UNNECESSARY means, that no more checks are required.
 * Otherwise, csum completion requires chacksumming packet body,
 * including udp header and folding it to skb->csum.
 */
static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
				 int proto)
{
	const struct iphdr *iph;
	int err;

	UDP_SKB_CB(skb)->partial_cov = 0;
	UDP_SKB_CB(skb)->cscov = skb->len;

	if (proto == IPPROTO_UDPLITE) {
		err = udplite_checksum_init(skb, uh);
		if (err)
			return err;
	}

	iph = ip_hdr(skb);
	if (uh->check == 0) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
E
Eric Dumazet 已提交
1293
		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310
				      proto, skb->csum))
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}
	if (!skb_csum_unnecessary(skb))
		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
					       skb->len, proto, 0);
	/* Probably, we should checksum udp header (it should be in cache
	 * in any case) and data in tiny packets (< rx copybreak).
	 */

	return 0;
}

/*
 *	All we need to do is get the socket, and then do a checksum.
 */

1311
int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1312 1313 1314
		   int proto)
{
	struct sock *sk;
1315
	struct udphdr *uh;
1316
	unsigned short ulen;
E
Eric Dumazet 已提交
1317
	struct rtable *rt = skb_rtable(skb);
1318
	__be32 saddr, daddr;
1319
	struct net *net = dev_net(skb->dev);
1320 1321 1322 1323 1324 1325 1326

	/*
	 *  Validate the packet.
	 */
	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
		goto drop;		/* No space for header. */

1327
	uh   = udp_hdr(skb);
1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341
	ulen = ntohs(uh->len);
	if (ulen > skb->len)
		goto short_packet;

	if (proto == IPPROTO_UDP) {
		/* UDP validates ulen. */
		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
			goto short_packet;
		uh = udp_hdr(skb);
	}

	if (udp4_csum_init(skb, uh, proto))
		goto csum_error;

1342 1343 1344
	saddr = ip_hdr(skb)->saddr;
	daddr = ip_hdr(skb)->daddr;

1345
	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1346 1347
		return __udp4_lib_mcast_deliver(net, skb, uh,
				saddr, daddr, udptable);
1348

1349
	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1350 1351

	if (sk != NULL) {
H
Herbert Xu 已提交
1352
		int ret = udp_queue_rcv_skb(sk, skb);
1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370
		sock_put(sk);

		/* a return value > 0 means to resubmit the input, but
		 * it wants the return to be -protocol, or 0
		 */
		if (ret > 0)
			return -ret;
		return 0;
	}

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto drop;
	nf_reset(skb);

	/* No socket. Drop packet silently, if checksum is wrong */
	if (udp_lib_checksum_complete(skb))
		goto csum_error;

1371
	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	/*
	 * Hmm.  We got an UDP packet to a port to which we
	 * don't wanna listen.  Ignore it.
	 */
	kfree_skb(skb);
	return 0;

short_packet:
1382
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1383
		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1384
		       &saddr,
1385 1386 1387
		       ntohs(uh->source),
		       ulen,
		       skb->len,
1388
		       &daddr,
1389 1390 1391 1392 1393 1394 1395 1396
		       ntohs(uh->dest));
	goto drop;

csum_error:
	/*
	 * RFC1122: OK.  Discards the bad packet silently (as far as
	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
	 */
1397
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1398
		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1399
		       &saddr,
1400
		       ntohs(uh->source),
1401
		       &daddr,
1402 1403 1404
		       ntohs(uh->dest),
		       ulen);
drop:
1405
	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1406 1407 1408 1409 1410 1411
	kfree_skb(skb);
	return 0;
}

int udp_rcv(struct sk_buff *skb)
{
1412
	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1413 1414
}

1415
void udp_destroy_sock(struct sock *sk)
1416 1417 1418 1419 1420 1421
{
	lock_sock(sk);
	udp_flush_pending_frames(sk);
	release_sock(sk);
}

L
Linus Torvalds 已提交
1422 1423 1424
/*
 *	Socket option code for UDP
 */
1425
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1426
		       char __user *optval, unsigned int optlen,
1427
		       int (*push_pending_frames)(struct sock *))
L
Linus Torvalds 已提交
1428 1429 1430 1431
{
	struct udp_sock *up = udp_sk(sk);
	int val;
	int err = 0;
W
Wang Chen 已提交
1432
	int is_udplite = IS_UDPLITE(sk);
L
Linus Torvalds 已提交
1433

E
Eric Dumazet 已提交
1434
	if (optlen < sizeof(int))
L
Linus Torvalds 已提交
1435 1436 1437 1438 1439
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

1440
	switch (optname) {
L
Linus Torvalds 已提交
1441 1442 1443 1444 1445 1446
	case UDP_CORK:
		if (val != 0) {
			up->corkflag = 1;
		} else {
			up->corkflag = 0;
			lock_sock(sk);
1447
			(*push_pending_frames)(sk);
L
Linus Torvalds 已提交
1448 1449 1450
			release_sock(sk);
		}
		break;
1451

L
Linus Torvalds 已提交
1452 1453 1454 1455 1456
	case UDP_ENCAP:
		switch (val) {
		case 0:
		case UDP_ENCAP_ESPINUDP:
		case UDP_ENCAP_ESPINUDP_NON_IKE:
1457 1458
			up->encap_rcv = xfrm4_udp_encap_rcv;
			/* FALLTHROUGH */
1459
		case UDP_ENCAP_L2TPINUDP:
L
Linus Torvalds 已提交
1460 1461 1462 1463 1464 1465 1466 1467
			up->encap_type = val;
			break;
		default:
			err = -ENOPROTOOPT;
			break;
		}
		break;

1468 1469 1470 1471 1472 1473
	/*
	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
	 */
	/* The sender sets actual checksum coverage length via this option.
	 * The case coverage > packet length is handled by send module. */
	case UDPLITE_SEND_CSCOV:
W
Wang Chen 已提交
1474
		if (!is_udplite)         /* Disable the option on UDP sockets */
1475 1476 1477
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
			val = 8;
1478 1479
		else if (val > USHORT_MAX)
			val = USHORT_MAX;
1480 1481 1482 1483
		up->pcslen = val;
		up->pcflag |= UDPLITE_SEND_CC;
		break;

1484 1485
	/* The receiver specifies a minimum checksum coverage value. To make
	 * sense, this should be set to at least 8 (as done below). If zero is
1486 1487
	 * used, this again means full checksum coverage.                     */
	case UDPLITE_RECV_CSCOV:
W
Wang Chen 已提交
1488
		if (!is_udplite)         /* Disable the option on UDP sockets */
1489 1490 1491
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
			val = 8;
1492 1493
		else if (val > USHORT_MAX)
			val = USHORT_MAX;
1494 1495 1496 1497
		up->pcrlen = val;
		up->pcflag |= UDPLITE_RECV_CC;
		break;

L
Linus Torvalds 已提交
1498 1499 1500
	default:
		err = -ENOPROTOOPT;
		break;
1501
	}
L
Linus Torvalds 已提交
1502 1503 1504

	return err;
}
E
Eric Dumazet 已提交
1505
EXPORT_SYMBOL(udp_lib_setsockopt);
L
Linus Torvalds 已提交
1506

1507
int udp_setsockopt(struct sock *sk, int level, int optname,
1508
		   char __user *optval, unsigned int optlen)
1509 1510 1511 1512 1513 1514 1515 1516 1517
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_push_pending_frames);
	return ip_setsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1518
			  char __user *optval, unsigned int optlen)
1519 1520 1521 1522 1523 1524 1525 1526
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_push_pending_frames);
	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
}
#endif

1527 1528
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
		       char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
1529 1530 1531 1532
{
	struct udp_sock *up = udp_sk(sk);
	int val, len;

E
Eric Dumazet 已提交
1533
	if (get_user(len, optlen))
L
Linus Torvalds 已提交
1534 1535 1536
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));
1537

1538
	if (len < 0)
L
Linus Torvalds 已提交
1539 1540
		return -EINVAL;

1541
	switch (optname) {
L
Linus Torvalds 已提交
1542 1543 1544 1545 1546 1547 1548 1549
	case UDP_CORK:
		val = up->corkflag;
		break;

	case UDP_ENCAP:
		val = up->encap_type;
		break;

1550 1551 1552 1553 1554 1555 1556 1557 1558 1559
	/* The following two cannot be changed on UDP sockets, the return is
	 * always 0 (which corresponds to the full checksum coverage of UDP). */
	case UDPLITE_SEND_CSCOV:
		val = up->pcslen;
		break;

	case UDPLITE_RECV_CSCOV:
		val = up->pcrlen;
		break;

L
Linus Torvalds 已提交
1560 1561
	default:
		return -ENOPROTOOPT;
1562
	}
L
Linus Torvalds 已提交
1563

1564
	if (put_user(len, optlen))
1565
		return -EFAULT;
E
Eric Dumazet 已提交
1566
	if (copy_to_user(optval, &val, len))
L
Linus Torvalds 已提交
1567
		return -EFAULT;
1568
	return 0;
L
Linus Torvalds 已提交
1569
}
E
Eric Dumazet 已提交
1570
EXPORT_SYMBOL(udp_lib_getsockopt);
L
Linus Torvalds 已提交
1571

1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588
int udp_getsockopt(struct sock *sk, int level, int optname,
		   char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return ip_getsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
int compat_udp_getsockopt(struct sock *sk, int level, int optname,
				 char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
}
#endif
L
Linus Torvalds 已提交
1589 1590 1591 1592 1593 1594
/**
 * 	udp_poll - wait for a UDP event.
 *	@file - file struct
 *	@sock - socket
 *	@wait - poll table
 *
1595
 *	This is same as datagram poll, except for the special case of
L
Linus Torvalds 已提交
1596 1597 1598 1599 1600 1601 1602 1603 1604 1605
 *	blocking sockets. If application is using a blocking fd
 *	and a packet with checksum error is in the queue;
 *	then it could get return from select indicating data available
 *	but then block when reading it. Add special case code
 *	to work around these arguably broken applications.
 */
unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask = datagram_poll(file, sock, wait);
	struct sock *sk = sock->sk;
1606

L
Linus Torvalds 已提交
1607
	/* Check for false positives due to checksum errors */
E
Eric Dumazet 已提交
1608 1609 1610
	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
		mask &= ~(POLLIN | POLLRDNORM);
L
Linus Torvalds 已提交
1611 1612

	return mask;
1613

L
Linus Torvalds 已提交
1614
}
E
Eric Dumazet 已提交
1615
EXPORT_SYMBOL(udp_poll);
L
Linus Torvalds 已提交
1616

1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629
struct proto udp_prot = {
	.name		   = "UDP",
	.owner		   = THIS_MODULE,
	.close		   = udp_lib_close,
	.connect	   = ip4_datagram_connect,
	.disconnect	   = udp_disconnect,
	.ioctl		   = udp_ioctl,
	.destroy	   = udp_destroy_sock,
	.setsockopt	   = udp_setsockopt,
	.getsockopt	   = udp_getsockopt,
	.sendmsg	   = udp_sendmsg,
	.recvmsg	   = udp_recvmsg,
	.sendpage	   = udp_sendpage,
H
Herbert Xu 已提交
1630
	.backlog_rcv	   = __udp_queue_rcv_skb,
1631 1632 1633 1634 1635 1636 1637 1638
	.hash		   = udp_lib_hash,
	.unhash		   = udp_lib_unhash,
	.get_port	   = udp_v4_get_port,
	.memory_allocated  = &udp_memory_allocated,
	.sysctl_mem	   = sysctl_udp_mem,
	.sysctl_wmem	   = &sysctl_udp_wmem_min,
	.sysctl_rmem	   = &sysctl_udp_rmem_min,
	.obj_size	   = sizeof(struct udp_sock),
1639
	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1640
	.h.udp_table	   = &udp_table,
1641 1642 1643 1644 1645
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_udp_setsockopt,
	.compat_getsockopt = compat_udp_getsockopt,
#endif
};
E
Eric Dumazet 已提交
1646
EXPORT_SYMBOL(udp_prot);
L
Linus Torvalds 已提交
1647 1648 1649 1650

/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS

1651
static struct sock *udp_get_first(struct seq_file *seq, int start)
L
Linus Torvalds 已提交
1652 1653 1654
{
	struct sock *sk;
	struct udp_iter_state *state = seq->private;
1655
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1656

1657 1658
	for (state->bucket = start; state->bucket <= state->udp_table->mask;
	     ++state->bucket) {
1659
		struct hlist_nulls_node *node;
1660
		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1661 1662 1663 1664

		if (hlist_nulls_empty(&hslot->head))
			continue;

1665
		spin_lock_bh(&hslot->lock);
1666
		sk_nulls_for_each(sk, node, &hslot->head) {
1667
			if (!net_eq(sock_net(sk), net))
1668
				continue;
L
Linus Torvalds 已提交
1669 1670 1671
			if (sk->sk_family == state->family)
				goto found;
		}
1672
		spin_unlock_bh(&hslot->lock);
L
Linus Torvalds 已提交
1673 1674 1675 1676 1677 1678 1679 1680 1681
	}
	sk = NULL;
found:
	return sk;
}

static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
{
	struct udp_iter_state *state = seq->private;
1682
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1683 1684

	do {
1685
		sk = sk_nulls_next(sk);
1686
	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
L
Linus Torvalds 已提交
1687

1688
	if (!sk) {
1689
		if (state->bucket <= state->udp_table->mask)
1690
			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
1691
		return udp_get_first(seq, state->bucket + 1);
L
Linus Torvalds 已提交
1692 1693 1694 1695 1696 1697
	}
	return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
1698
	struct sock *sk = udp_get_first(seq, 0);
L
Linus Torvalds 已提交
1699 1700

	if (sk)
1701
		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
L
Linus Torvalds 已提交
1702 1703 1704 1705 1706 1707
			--pos;
	return pos ? NULL : sk;
}

static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
1708
	struct udp_iter_state *state = seq->private;
1709
	state->bucket = MAX_UDP_PORTS;
1710

1711
	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
1712 1713 1714 1715 1716 1717
}

static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct sock *sk;

1718
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
1719 1720 1721 1722 1723 1724 1725 1726 1727 1728
		sk = udp_get_idx(seq, 0);
	else
		sk = udp_get_next(seq, v);

	++*pos;
	return sk;
}

static void udp_seq_stop(struct seq_file *seq, void *v)
{
1729 1730
	struct udp_iter_state *state = seq->private;

1731
	if (state->bucket <= state->udp_table->mask)
1732
		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
L
Linus Torvalds 已提交
1733 1734 1735 1736 1737
}

static int udp_seq_open(struct inode *inode, struct file *file)
{
	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
1738 1739
	struct udp_iter_state *s;
	int err;
1740

1741 1742 1743 1744
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			   sizeof(struct udp_iter_state));
	if (err < 0)
		return err;
1745

1746
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
1747
	s->family		= afinfo->family;
1748
	s->udp_table		= afinfo->udp_table;
1749
	return err;
1750 1751
}

L
Linus Torvalds 已提交
1752
/* ------------------------------------------------------------------------ */
1753
int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
1754 1755 1756 1757
{
	struct proc_dir_entry *p;
	int rc = 0;

1758 1759 1760 1761
	afinfo->seq_fops.open		= udp_seq_open;
	afinfo->seq_fops.read		= seq_read;
	afinfo->seq_fops.llseek		= seq_lseek;
	afinfo->seq_fops.release	= seq_release_net;
L
Linus Torvalds 已提交
1762

1763 1764 1765 1766
	afinfo->seq_ops.start		= udp_seq_start;
	afinfo->seq_ops.next		= udp_seq_next;
	afinfo->seq_ops.stop		= udp_seq_stop;

1767 1768 1769
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
			     &afinfo->seq_fops, afinfo);
	if (!p)
L
Linus Torvalds 已提交
1770 1771 1772
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
1773
EXPORT_SYMBOL(udp_proc_register);
L
Linus Torvalds 已提交
1774

1775
void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
1776
{
1777
	proc_net_remove(net, afinfo->name);
L
Linus Torvalds 已提交
1778
}
E
Eric Dumazet 已提交
1779
EXPORT_SYMBOL(udp_proc_unregister);
1780 1781

/* ------------------------------------------------------------------------ */
1782 1783
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
		int bucket, int *len)
1784 1785
{
	struct inet_sock *inet = inet_sk(sp);
E
Eric Dumazet 已提交
1786 1787 1788 1789
	__be32 dest = inet->inet_daddr;
	__be32 src  = inet->inet_rcv_saddr;
	__u16 destp	  = ntohs(inet->inet_dport);
	__u16 srcp	  = ntohs(inet->inet_sport);
1790

1791
	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
E
Eric Dumazet 已提交
1792
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d%n",
1793
		bucket, src, srcp, dest, destp, sp->sk_state,
1794 1795
		sk_wmem_alloc_get(sp),
		sk_rmem_alloc_get(sp),
1796
		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
E
Eric Dumazet 已提交
1797 1798
		atomic_read(&sp->sk_refcnt), sp,
		atomic_read(&sp->sk_drops), len);
1799 1800 1801 1802 1803 1804 1805 1806
}

int udp4_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "%-127s\n",
			   "  sl  local_address rem_address   st tx_queue "
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
E
Eric Dumazet 已提交
1807
			   "inode ref pointer drops");
1808 1809
	else {
		struct udp_iter_state *state = seq->private;
1810
		int len;
1811

1812
		udp4_format_sock(v, seq, state->bucket, &len);
E
Eric Dumazet 已提交
1813
		seq_printf(seq, "%*s\n", 127 - len, "");
1814 1815 1816 1817 1818 1819 1820 1821
	}
	return 0;
}

/* ------------------------------------------------------------------------ */
static struct udp_seq_afinfo udp4_seq_afinfo = {
	.name		= "udp",
	.family		= AF_INET,
1822
	.udp_table	= &udp_table,
1823 1824 1825
	.seq_fops	= {
		.owner	=	THIS_MODULE,
	},
1826 1827 1828
	.seq_ops	= {
		.show		= udp4_seq_show,
	},
1829 1830
};

1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845
static int udp4_proc_init_net(struct net *net)
{
	return udp_proc_register(net, &udp4_seq_afinfo);
}

static void udp4_proc_exit_net(struct net *net)
{
	udp_proc_unregister(net, &udp4_seq_afinfo);
}

static struct pernet_operations udp4_net_ops = {
	.init = udp4_proc_init_net,
	.exit = udp4_proc_exit_net,
};

1846 1847
int __init udp4_proc_init(void)
{
1848
	return register_pernet_subsys(&udp4_net_ops);
1849 1850 1851 1852
}

void udp4_proc_exit(void)
{
1853
	unregister_pernet_subsys(&udp4_net_ops);
1854
}
L
Linus Torvalds 已提交
1855 1856
#endif /* CONFIG_PROC_FS */

1857 1858
static __initdata unsigned long uhash_entries;
static int __init set_uhash_entries(char *str)
1859
{
1860 1861 1862 1863 1864 1865 1866 1867
	if (!str)
		return 0;
	uhash_entries = simple_strtoul(str, &str, 0);
	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
		uhash_entries = UDP_HTABLE_SIZE_MIN;
	return 1;
}
__setup("uhash_entries=", set_uhash_entries);
1868

1869 1870 1871 1872 1873 1874
void __init udp_table_init(struct udp_table *table, const char *name)
{
	unsigned int i;

	if (!CONFIG_BASE_SMALL)
		table->hash = alloc_large_system_hash(name,
1875
			2 * sizeof(struct udp_hslot),
1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886
			uhash_entries,
			21, /* one slot per 2 MB */
			0,
			&table->log,
			&table->mask,
			64 * 1024);
	/*
	 * Make sure hash table has the minimum size
	 */
	if (CONFIG_BASE_SMALL || table->mask < UDP_HTABLE_SIZE_MIN - 1) {
		table->hash = kmalloc(UDP_HTABLE_SIZE_MIN *
1887
				      2 * sizeof(struct udp_hslot), GFP_KERNEL);
1888 1889 1890 1891 1892
		if (!table->hash)
			panic(name);
		table->log = ilog2(UDP_HTABLE_SIZE_MIN);
		table->mask = UDP_HTABLE_SIZE_MIN - 1;
	}
1893
	table->hash2 = table->hash + (table->mask + 1);
1894
	for (i = 0; i <= table->mask; i++) {
1895
		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
E
Eric Dumazet 已提交
1896
		table->hash[i].count = 0;
1897 1898
		spin_lock_init(&table->hash[i].lock);
	}
1899 1900 1901 1902 1903
	for (i = 0; i <= table->mask; i++) {
		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
		table->hash2[i].count = 0;
		spin_lock_init(&table->hash2[i].lock);
	}
1904 1905
}

H
Hideo Aoki 已提交
1906 1907
void __init udp_init(void)
{
1908
	unsigned long nr_pages, limit;
H
Hideo Aoki 已提交
1909

1910
	udp_table_init(&udp_table, "UDP");
H
Hideo Aoki 已提交
1911 1912 1913 1914
	/* Set the pressure threshold up by the same strategy of TCP. It is a
	 * fraction of global memory that is up to 1/2 at 256 MB, decreasing
	 * toward zero with the amount of memory, with a floor of 128 pages.
	 */
1915 1916 1917
	nr_pages = totalram_pages - totalhigh_pages;
	limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
	limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
H
Hideo Aoki 已提交
1918 1919 1920 1921 1922 1923 1924 1925 1926
	limit = max(limit, 128UL);
	sysctl_udp_mem[0] = limit / 4 * 3;
	sysctl_udp_mem[1] = limit;
	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;

	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
}

1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
int udp4_ufo_send_check(struct sk_buff *skb)
{
	const struct iphdr *iph;
	struct udphdr *uh;

	if (!pskb_may_pull(skb, sizeof(*uh)))
		return -EINVAL;

	iph = ip_hdr(skb);
	uh = udp_hdr(skb);

	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
				       IPPROTO_UDP, 0);
	skb->csum_start = skb_transport_header(skb) - skb->head;
	skb->csum_offset = offsetof(struct udphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;
	return 0;
}

struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features)
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	unsigned int mss;
	int offset;
	__wsum csum;

	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
			     !(type & (SKB_GSO_UDP))))
			goto out;

		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);

		segs = NULL;
		goto out;
	}

	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
	 * do checksum of UDP packets sent as multiple IP fragments.
	 */
	offset = skb->csum_start - skb_headroom(skb);
E
Eric Dumazet 已提交
1975
	csum = skb_checksum(skb, offset, skb->len - offset, 0);
1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
	offset += skb->csum_offset;
	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
	skb->ip_summed = CHECKSUM_NONE;

	/* Fragment the skb. IP headers of the fragments are updated in
	 * inet_gso_segment()
	 */
	segs = skb_segment(skb, features);
out:
	return segs;
}