path: root/net/ipv4/ping.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.
 *
 *		"Ping" sockets
 *
 *		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.
 *
 * Based on ipv4/udp.c code.
 *
 * Authors:	Vasiliy Kulikov / Openwall (for Linux 2.6),
 *		Pavel Kankovsky (for Linux 2.4.32)
 *
 * Pavel gave all rights to bugs to Vasiliy,
 * none of the bugs are Pavel's now.
 *
 */

#include <asm/system.h>
#include <linux/uaccess.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/sockios.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/snmp.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/icmp.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/export.h>
#include <net/sock.h>
#include <net/ping.h>
#include <net/udp.h>
#include <net/route.h>
#include <net/inet_common.h>
#include <net/checksum.h>


static struct ping_table ping_table;

static u16 ping_port_rover;

static inline int ping_hashfn(struct net *net, unsigned num, unsigned mask)
{
	int res = (num + net_hash_mix(net)) & mask;
	pr_debug("hash(%d) = %d\n", num, res);
	return res;
}

static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
					     struct net *net, unsigned num)
{
	return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
}

static int ping_v4_get_port(struct sock *sk, unsigned short ident)
{
	struct hlist_nulls_node *node;
	struct hlist_nulls_head *hlist;
	struct inet_sock *isk, *isk2;
	struct sock *sk2 = NULL;

	isk = inet_sk(sk);
	write_lock_bh(&ping_table.lock);
	if (ident == 0) {
		u32 i;
		u16 result = ping_port_rover + 1;

		for (i = 0; i < (1L << 16); i++, result++) {
			if (!result)
				result++; /* avoid zero */
			hlist = ping_hashslot(&ping_table, sock_net(sk),
					    result);
			ping_portaddr_for_each_entry(sk2, node, hlist) {
				isk2 = inet_sk(sk2);

				if (isk2->inet_num == result)
					goto next_port;
			}

			/* found */
			ping_port_rover = ident = result;
			break;
next_port:
			;
		}
		if (i >= (1L << 16))
			goto fail;
	} else {
		hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
		ping_portaddr_for_each_entry(sk2, node, hlist) {
			isk2 = inet_sk(sk2);

			if ((isk2->inet_num == ident) &&
			    (sk2 != sk) &&
			    (!sk2->sk_reuse || !sk->sk_reuse))
				goto fail;
		}
	}

	pr_debug("found port/ident = %d\n", ident);
	isk->inet_num = ident;
	if (sk_unhashed(sk)) {
		pr_debug("was not hashed\n");
		sock_hold(sk);
		hlist_nulls_add_head(&sk->sk_nulls_node, hlist);
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
	}
	write_unlock_bh(&ping_table.lock);
	return 0;

fail:
	write_unlock_bh(&ping_table.lock);
	return 1;
}

static void ping_v4_hash(struct sock *sk)
{
	pr_debug("ping_v4_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
	BUG(); /* "Please do not press this button again." */
}

static void ping_v4_unhash(struct sock *sk)
{
	struct inet_sock *isk = inet_sk(sk);
	pr_debug("ping_v4_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
	if (sk_hashed(sk)) {
		write_lock_bh(&ping_table.lock);
		hlist_nulls_del(&sk->sk_nulls_node);
		sock_put(sk);
		isk->inet_num = 0;
		isk->inet_sport = 0;
		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
		write_unlock_bh(&ping_table.lock);
	}
}

static struct sock *ping_v4_lookup(struct net *net, __be32 saddr, __be32 daddr,
				   u16 ident, int dif)
{
	struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
	struct sock *sk = NULL;
	struct inet_sock *isk;
	struct hlist_nulls_node *hnode;

	pr_debug(</