path: root/net/ipv4/udp_ipv4.c

/*
 * 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.
 *
 *		UDP for IPv4.
 *
 *		For full credits, see net/ipv4/udp.c.
 *
 *		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.
 */

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <linux/bootmem.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/igmp.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <net/tcp_states.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/net_namespace.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
#include "udp_impl.h"

int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
{
	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);

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

static inline int udp_v4_get_port(struct sock *sk, unsigned short snum)
{
	return udp_get_port(sk, snum, ipv4_rcv_saddr_equal);
}

/* 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,
		int dif, struct hlist_head udptable[])
{
	struct sock *sk, *result = NULL;
	struct hlist_node *node;
	unsigned short hnum = ntohs(dport);
	int badness = -1;

	read_lock(&udp_hash_lock);
	sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) {
		struct inet_sock *inet = inet_sk(sk);

		if (sk->sk_net == net && sk->sk_hash == hnum &&
				!ipv6_only_sock(sk)) {
			int score = (sk->sk_family == PF_INET ? 1 : 0);
			if (inet->rcv_saddr) {
				if (inet->rcv_saddr != daddr)
					continue;
				score+=2;
			}
			if (inet->daddr) {
				if (inet->daddr != saddr)
					continue;
				score+=2;
			}
			if (inet->dport) {
				if (inet->dport != sport)
					continue;
				score+=2;
			}
			if (sk->sk_bound_dev_if) {
				if (sk->sk_bound_dev_if != dif)
					continue;
				score+=2;
			}
			if (score == 9) {
				result = sk;
				break;
			} else if (score > badness) {
				result = sk;
				badness = score;
			}
		}
	}
	if (result)
		sock_hold(result);
	read_unlock(&udp_hash_lock);
	return result;
}

static inline struct sock *udp_v4_mcast_next(struct sock *sk,
					     __be16 loc_port, __be32 loc_addr,