path: root/net/dccp/proto.c

/*
 *  net/dccp/proto.c
 *
 *  An implementation of the DCCP protocol
 *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 *	This program is free software; you can redistribute it and/or modify it
 *	under the terms of the GNU General Public License version 2 as
 *	published by the Free Software Foundation.
 */

#include <linux/config.h>
#include <linux/dccp.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/in.h>
#include <linux/if_arp.h>
#include <linux/init.h>
#include <linux/random.h>
#include <net/checksum.h>

#include <net/inet_common.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/sock.h>
#include <net/xfrm.h>

#include <asm/semaphore.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/dccp.h>

#include "ccid.h"
#include "dccp.h"

DEFINE_SNMP_STAT(struct dccp_mib, dccp_statistics) __read_mostly;

atomic_t dccp_orphan_count = ATOMIC_INIT(0);

static struct net_protocol dccp_protocol = {
	.handler	= dccp_v4_rcv,
	.err_handler	= dccp_v4_err,
};

const char *dccp_packet_name(const int type)
{
	static const char *dccp_packet_names[] = {
		[DCCP_PKT_REQUEST]  = "REQUEST",
		[DCCP_PKT_RESPONSE] = "RESPONSE",
		[DCCP_PKT_DATA]	    = "DATA",
		[DCCP_PKT_ACK]	    = "ACK",
		[DCCP_PKT_DATAACK]  = "DATAACK",
		[DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
		[DCCP_PKT_CLOSE]    = "CLOSE",
		[DCCP_PKT_RESET]    = "RESET",
		[DCCP_PKT_SYNC]	    = "SYNC",
		[DCCP_PKT_SYNCACK]  = "SYNCACK",
	};

	if (type >= DCCP_NR_PKT_TYPES)
		return "INVALID";
	else
		return dccp_packet_names[type];
}

EXPORT_SYMBOL_GPL(dccp_packet_name);

const char *dccp_state_name(const int state)
{
	static char *dccp_state_names[] = {
	[DCCP_OPEN]	  = "OPEN",
	[DCCP_REQUESTING] = "REQUESTING",
	[DCCP_PARTOPEN]	  = "PARTOPEN",
	[DCCP_LISTEN]	  = "LISTEN",
	[DCCP_RESPOND]	  = "RESPOND",
	[DCCP_CLOSING]	  = "CLOSING",
	[DCCP_TIME_WAIT]  = "TIME_WAIT",
	[DCCP_CLOSED]	  = "CLOSED",
	};

	if (state >= DCCP_MAX_STATES)
		return "INVALID STATE!";
	else
		return dccp_state_names[state];
}

EXPORT_SYMBOL_GPL(dccp_state_name);

static inline int dccp_listen_start(struct sock *sk)
{
	struct dccp_sock *dp = dccp_sk(sk);

	dp->dccps_role = DCCP_ROLE_LISTEN;
	/*
	 * Apps need to use setsockopt(DCCP_SOCKOPT_SERVICE)
	 * before calling listen()
	 */
	if (dccp_service_not_initialized(sk))
		return -EPROTO;
	return inet_csk_listen_start(sk, TCP_SYNQ_HSIZE);
}

int dccp_disconnect(struct sock *sk, int flags)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct inet_sock *inet = inet_sk(sk);
	int err = 0;
	const int old_state = sk->sk_state;

	if (old_state != DCCP_CLOSED)
		dccp_set_state(sk, DCCP_CLOSED);

	/* ABORT function of RFC793 */
	if (old_state == DCCP_LISTEN) {
		inet_csk_listen_stop(sk);
	/* FIXME: do the active reset thing */
	} else if (old_state == DCCP_REQUESTING)
		sk->sk_err = ECONNRESET;

	dccp_clear_xmit_timers(sk);
	__skb_queue_purge(&sk->sk_receive_queue);
	if (sk->sk_send_head != NULL) {
		__kfree_skb(sk->sk_send_head);
		sk->sk_send_head = NULL;
	}

	inet->dport = 0;

	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	sk->sk_shutdown = 0;
	sock_reset_flag(sk, SOCK_DONE);

	icsk->icsk_backoff = 0;
	inet_csk_delack_init(sk);
	__sk_dst_reset(sk);

	BUG_TRAP(!inet->num || icsk->icsk_bind_hash);

	sk->sk_error_report(sk);
	return err;
}

/*
 *	Wait for a DCCP event.
 *
 *	Note that we don't need to lock the socket, as the upper poll layers
 *	take care of normal races (between the test and the event) and we don't
 *	go look at any of the socket buffers directly.
 */
static unsigned int dccp_poll(struct file *file, struct socket *sock,
			      poll_table *wait)
{
	unsigned int mask;
	struct sock *sk = sock->sk;

	poll_wait(file, sk->sk_sleep, wait);
	if (sk->sk_state == DCCP_LISTEN)
		return inet_csk_listen_poll(sk);

	/* Socket is not locked. We are protected from async events
	   by poll logic and correct handling of state changes
	   made by another threads is impossible in any case.
	 */

	mask = 0;
	if (sk->sk_err)
		mask = POLLERR;

	if (sk->sk_shutdown == SHUTDOWN_MASK || sk->sk_state == DCCP_CLOSED)
		mask |= POLLHUP;
	if (sk->sk_shutdown & RCV_SHUTDOWN)
		mask |= POLLIN | POLLRDNORM;

	/* Connected? */
	if ((1