[DCCP]: Initial implementation

Development to this point was done on a subversion repository at:

http://oops.ghostprotocols.net:81/cgi-bin/viewcvs.cgi/dccp-2.6/

This repository will be kept at this site for the foreseable future,
so that interested parties can see the history of this code,
attributions, etc.

If I ever decide to take this offline I'll provide the full history at
some other suitable place.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 818 insertions, 0 deletions

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
new file mode 100644
index 000000000000..70284e6afe05
--- /dev/null
+++ b/net/dccp/proto.c
@@ -0,0 +1,818 @@
+/*
+ *  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);
+
+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)
+{
+	dccp_sk(sk)->dccps_role = DCCP_ROLE_LISTEN;
+	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;
+}
+
+int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+	dccp_pr_debug("entry\n");
+	return -ENOIOCTLCMD;
+}
+
+int dccp_setsockopt(struct sock *sk, int level, int optname,
+		    char *optval, int optlen)
+{
+	dccp_pr_debug("entry\n");
+
+	if (level != SOL_DCCP)
+		return ip_setsockopt(sk, level, optname, optval, optlen);
+
+	return -EOPNOTSUPP;
+}
+
+int dccp_getsockopt(struct sock *sk, int level, int optname,
+		    char *optval, int *optlen)
+{
+	dccp_pr_debug("entry\n");
+
+	if (level != SOL_DCCP)
+		return ip_getsockopt(sk, level, optname, optval, optlen);
+
+	return -EOPNOTSUPP;
+}
+
+int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+		 size_t len)
+{
+	const struct dccp_sock *dp = dccp_sk(sk);
+	const int flags = msg->msg_flags;
+	const int noblock = flags & MSG_DONTWAIT;
+	struct sk_buff *skb;
+	int rc, size;
+	long timeo;
+
+	if (len > dp->dccps_mss_cache)
+		return -EMSGSIZE;
+
+	lock_sock(sk);
+
+	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+
+	/*
+	 * We have to use sk_stream_wait_connect here to set sk_write_pending,
+	 * so that the trick in dccp_rcv_request_sent_state_process.
+	 */
+	/* Wait for a connection to finish. */
+	if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN | DCCPF_CLOSING))
+		if ((rc = sk_stream_wait_connect(sk, &timeo)) != 0)
+			goto out_err;
+
+	size = sk->sk_prot->max_header + len;
+	release_sock(sk);
+	skb = sock_alloc_send_skb(sk, size, noblock, &rc);
+	lock_sock(sk);
+
+	if (skb == NULL)
+		goto out_release;
+
+	skb_reserve(skb, sk->sk_prot->max_header);
+	rc = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
+	if (rc == 0) {
+		struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+		const struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
+		long delay; 
+
+		/*
+		 * XXX: This is just to match the Waikato tree CA interaction
+		 * points, after the CCID3 code is stable and I have a better
+		 * understanding of behaviour I'll change this to look more like
+		 * TCP.
+		 */
+		while (1) {
+			rc = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk,
+						    skb, len, &delay);
+			if (rc == 0)
+				break;
+			if (rc != -EAGAIN)
+				goto out_discard;
+			if (delay > timeo)
+				goto out_discard;
+			release_sock(sk);
+			delay = schedule_timeout(delay);
+			lock_sock(sk);
+			timeo -= delay;
+			if (signal_pending(current))
+				goto out_interrupted;
+			rc = -EPIPE;
+			if (!(sk->sk_state == DCCP_PARTOPEN || sk->sk_state == DCCP_OPEN))
+				goto out_discard;
+		}
+
+		if (sk->sk_state == DCCP_PARTOPEN) {
+			/* See 8.1.5.  Handshake Completion */
+			inet_csk_schedule_ack(sk);
+			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, inet_csk(sk)->icsk_rto, TCP_RTO_MAX);
+			dcb->dccpd_type = DCCP_PKT_DATAACK;
+			/* FIXME: we really should have a dccps_ack_pending or use icsk */
+		} else if (inet_csk_ack_scheduled(sk) ||
+			   (dp->dccps_options.dccpo_send_ack_vector &&
+			    ap->dccpap_buf_ackno != DCCP_MAX_SEQNO + 1 &&
+			    ap->dccpap_ack_seqno == DCCP_MAX_SEQNO + 1))
+			dcb->dccpd_type = DCCP_PKT_DATAACK;
+		else
+			dcb->dccpd_type = DCCP_PKT_DATA;
+		dccp_transmit_skb(sk, skb);
+		ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);
+	} else {
+out_discard:
+		kfree_skb(skb);
+	}
+out_release:
+	release_sock(sk);
+	return rc ? : len;
+out_err:
+	rc = sk_stream_error(sk, flags, rc);
+	goto out_release;
+out_interrupted:
+	rc = sock_intr_errno(timeo);
+	goto out_discard;
+}
+
+EXPORT_SYMBOL(dccp_sendmsg);
+
+int dccp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+		 size_t len, int nonblock, int flags, int *addr_len)
+{
+	const struct dccp_hdr *dh;
+	int copied = 0;
+	unsigned long used;
+	int err;
+	int target;		/* Read at least this many bytes */
+	long timeo;
+
+	lock_sock(sk);
+
+	err = -ENOTCONN;
+	if (sk->sk_state == DCCP_LISTEN)
+		goto out;
+
+	timeo = sock_rcvtimeo(sk, nonblock);
+
+	/* Urgent data needs to be handled specially. */
+	if (flags & MSG_OOB)
+		goto recv_urg;
+
+	/* FIXME */
+#if 0
+	seq = &tp->copied_seq;
+	if (flags & MSG_PEEK) {
+		peek_seq = tp->copied_seq;
+		seq = &peek_seq;
+	}
+#endif
+
+	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
+
+	do {
+		struct sk_buff *skb;
+		u32 offset;
+
+	/* FIXME */
+#if 0
+		/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
+		if (tp->urg_data && tp->urg_seq == *seq) {
+			if (copied)
+				break;
+			if (signal_pending(current)) {
+				copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
+				break;
+			}
+		}
+#endif
+
+		/* Next get a buffer. */
+
+		skb = skb_peek(&sk->sk_receive_queue);
+		do {
+			if (!skb)
+				break;
+
+			offset = 0;
+			dh = dccp_hdr(skb);
+
+			if (dh->dccph_type == DCCP_PKT_DATA ||
+			    dh->dccph_type == DCCP_PKT_DATAACK)
+				goto found_ok_skb;
+
+			if (dh->dccph_type == DCCP_PKT_RESET ||
+			    dh->dccph_type == DCCP_PKT_CLOSE) {
+				dccp_pr_debug("found fin ok!\n");
+				goto found_fin_ok;
+			}
+			dccp_pr_debug("packet_type=%s\n", dccp_packet_name(dh->dccph_type));
+			BUG_TRAP(flags & MSG_PEEK);
+			skb = skb->next;
+		} while (skb != (struct sk_buff *)&sk->sk_receive_queue);
+
+		/* Well, if we have backlog, try to process it now yet. */
+		if (copied >= target && !sk->sk_backlog.tail)
+			break;
+
+		if (copied) {
+			if (sk->sk_err ||
+			    sk->sk_state == DCCP_CLOSED ||
+			    (sk->sk_shutdown & RCV_SHUTDOWN) ||
+			    !timeo ||
+			    signal_pending(current) ||
+			    (flags & MSG_PEEK))
+				break;
+		} else {
+			if (sock_flag(sk, SOCK_DONE))
+				break;
+
+			if (sk->sk_err) {
+				copied = sock_error(sk);
+				break;
+			}
+
+			if (sk->sk_shutdown & RCV_SHUTDOWN)
+				break;
+
+			if (sk->sk_state == DCCP_CLOSED) {
+				if (!sock_flag(sk, SOCK_DONE)) {
+					/* This occurs when user tries to read
+					 * from never connected socket.
+					 */
+					copied = -ENOTCONN;
+					break;
+				}
+				break;
+			}
+
+			if (!timeo) {
+				copied = -EAGAIN;
+				break;
+			}
+
+			if (signal_pending(current)) {
+				copied = sock_intr_errno(timeo);
+				break;
+			}
+		}
+
+		/* FIXME: cleanup_rbuf(sk, copied); */
+
+		if (copied >= target) {
+			/* Do not sleep, just process backlog. */
+			release_sock(sk);
+			lock_sock(sk);
+		} else
+			sk_wait_data(sk, &timeo);
+
+		continue;
+
+	found_ok_skb:
+		/* Ok so how much can we use? */
+		used = skb->len - offset;
+		if (len < used)
+			used = len;
+
+		if (!(flags & MSG_TRUNC)) {
+			err = skb_copy_datagram_iovec(skb, offset,
+						      msg->msg_iov, used);
+			if (err) {
+				/* Exception. Bailout! */
+				if (!copied)
+					copied = -EFAULT;
+				break;
+			}
+		}
+
+		copied += used;
+		len -= used;
+
+		/* FIXME: tcp_rcv_space_adjust(sk); */
+
+//skip_copy:
+		if (used + offset < skb->len)
+			continue;
+
+		if (!(flags & MSG_PEEK))
+			sk_eat_skb(sk, skb);
+		continue;
+	found_fin_ok:
+		if (!(flags & MSG_PEEK))
+			sk_eat_skb(sk, skb);
+		break;
+		
+	} while (len > 0);
+
+	/* According to UNIX98, msg_name/msg_namelen are ignored
+	 * on connected socket. I was just happy when found this 8) --ANK
+	 */
+
+	/* Clean up data we have read: This will do ACK frames. */
+	/* FIXME: cleanup_rbuf(sk, copied); */
+
+	release_sock(sk);
+	return copied;
+
+out:
+	release_sock(sk);
+	return err;
+
+recv_urg:
+	/* FIXME: err = tcp_recv_urg(sk, timeo, msg, len, flags, addr_len); */
+	goto out;
+}
+
+static int inet_dccp_listen(struct socket *sock, int backlog)
+{
+	struct sock *sk = sock->sk;
+	unsigned char old_state;
+	int err;
+
+	lock_sock(sk);
+
+	err = -EINVAL;
+	if (sock->state != SS_UNCONNECTED || sock->type != SOCK_DCCP)
+		goto out;
+
+	old_state = sk->sk_state;
+	if (!((1 << old_state) & (DCCPF_CLOSED | DCCPF_LISTEN)))
+		goto out;
+
+	/* Really, if the socket is already in listen state
+	 * we can only allow the backlog to be adjusted.
+	 */
+	if (old_state != DCCP_LISTEN) {
+		/*
+		 * FIXME: here it probably should be sk->sk_prot->listen_start
+		 * see tcp_listen_start
+		 */
+		err = dccp_listen_start(sk);
+		if (err)
+			goto out;
+	}
+	sk->sk_max_ack_backlog = backlog;
+	err = 0;
+
+out:
+	release_sock(sk);
+	return err;
+}
+
+static const unsigned char dccp_new_state[] = {
+	/* current state:        new state:      action:	*/
+	[0]			= DCCP_CLOSED,
+	[DCCP_OPEN] 		= DCCP_CLOSING | DCCP_ACTION_FIN,
+	[DCCP_REQUESTING] 	= DCCP_CLOSED,
+	[DCCP_PARTOPEN]	= DCCP_CLOSING | DCCP_ACTION_FIN,
+	[DCCP_LISTEN]		= DCCP_CLOSED,
+	[DCCP_RESPOND] 	= DCCP_CLOSED,
+	[DCCP_CLOSING]	= DCCP_CLOSED,
+	[DCCP_TIME_WAIT] 	= DCCP_CLOSED,
+	[DCCP_CLOSED] 	= DCCP_CLOSED,
+};
+
+static int dccp_close_state(struct sock *sk)
+{
+	const int next = dccp_new_state[sk->sk_state];
+	const int ns = next & DCCP_STATE_MASK;
+
+	if (ns != sk->sk_state)
+		dccp_set_state(sk, ns);
+
+	return next & DCCP_ACTION_FIN;
+}
+
+void dccp_close(struct sock *sk, long timeout)
+{
+	struct sk_buff *skb;
+
+	lock_sock(sk);
+
+	sk->sk_shutdown = SHUTDOWN_MASK;
+
+	if (sk->sk_state == DCCP_LISTEN) {
+		dccp_set_state(sk, DCCP_CLOSED);
+
+		/* Special case. */
+		inet_csk_listen_stop(sk);
+
+		goto adjudge_to_death;
+	}
+
+	/*
+	 * We need to flush the recv. buffs.  We do this only on the
+	 * descriptor close, not protocol-sourced closes, because the
+	  *reader process may not have drained the data yet!
+	 */
+	/* FIXME: check for unread data */
+	while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
+		__kfree_skb(skb);
+	}
+
+	if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
+		/* Check zero linger _after_ checking for unread data. */
+		sk->sk_prot->disconnect(sk, 0);
+	} else if (dccp_close_state(sk)) {
+		dccp_send_close(sk);
+	}
+
+	sk_stream_wait_close(sk, timeout);
+
+adjudge_to_death:
+	release_sock(sk);
+	/*
+	 * Now socket is owned by kernel and we acquire BH lock
+	 * to finish close. No need to check for user refs.
+	 */
+	local_bh_disable();
+	bh_lock_sock(sk);
+	BUG_TRAP(!sock_owned_by_user(sk));
+
+	sock_hold(sk);
+	sock_orphan(sk);
+						
+	if (sk->sk_state != DCCP_CLOSED)
+		dccp_set_state(sk, DCCP_CLOSED);
+
+	atomic_inc(&dccp_orphan_count);
+	if (sk->sk_state == DCCP_CLOSED)
+		inet_csk_destroy_sock(sk);
+
+	/* Otherwise, socket is reprieved until protocol close. */
+
+	bh_unlock_sock(sk);
+	local_bh_enable();
+	sock_put(sk);
+}
+
+void dccp_shutdown(struct sock *sk, int how)
+{
+	dccp_pr_debug("entry\n");
+}
+
+struct proto_ops inet_dccp_ops = {
+	.family		= PF_INET,
+	.owner		= THIS_MODULE,
+	.release	= inet_release,
+	.bind		= inet_bind,
+	.connect	= inet_stream_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= inet_accept,
+	.getname	= inet_getname,
+	.poll		= sock_no_poll,
+	.ioctl		= inet_ioctl,
+	.listen		= inet_dccp_listen, /* FIXME: work on inet_listen to rename it to sock_common_listen */
+	.shutdown	= inet_shutdown,
+	.setsockopt	= sock_common_setsockopt,
+	.getsockopt	= sock_common_getsockopt,
+	.sendmsg	= inet_sendmsg,
+	.recvmsg	= sock_common_recvmsg,
+	.mmap		= sock_no_mmap,
+	.sendpage	= sock_no_sendpage,
+};
+
+extern struct net_proto_family inet_family_ops;
+
+static struct inet_protosw dccp_v4_protosw = {
+	.type		= SOCK_DCCP,
+	.protocol	= IPPROTO_DCCP,
+	.prot		= &dccp_v4_prot,
+	.ops		= &inet_dccp_ops,
+	.capability	= -1,
+	.no_check	= 0,
+	.flags		= 0,
+};
+
+/*
+ * This is the global socket data structure used for responding to
+ * the Out-of-the-blue (OOTB) packets. A control sock will be created
+ * for this socket at the initialization time.
+ */
+struct socket *dccp_ctl_socket;
+
+static char dccp_ctl_socket_err_msg[] __initdata =
+	KERN_ERR "DCCP: Failed to create the control socket.\n";
+
+static int __init dccp_ctl_sock_init(void)
+{
+	int rc = sock_create_kern(PF_INET, SOCK_DCCP, IPPROTO_DCCP,
+				  &dccp_ctl_socket);
+	if (rc < 0)
+		printk(dccp_ctl_socket_err_msg);
+	else {
+		dccp_ctl_socket->sk->sk_allocation = GFP_ATOMIC;
+		inet_sk(dccp_ctl_socket->sk)->uc_ttl = -1;
+
+		/* Unhash it so that IP input processing does not even
+		 * see it, we do not wish this socket to see incoming
+		 * packets.
+		 */
+		dccp_ctl_socket->sk->sk_prot->unhash(dccp_ctl_socket->sk);
+	}
+
+	return rc;
+}
+
+static void __exit dccp_ctl_sock_exit(void)
+{
+	if (dccp_ctl_socket != NULL)
+		sock_release(dccp_ctl_socket);
+}
+
+static int __init init_dccp_v4_mibs(void)
+{
+	int rc = -ENOMEM;
+
+	dccp_statistics[0] = alloc_percpu(struct dccp_mib);
+	if (dccp_statistics[0] == NULL)
+		goto out;
+
+	dccp_statistics[1] = alloc_percpu(struct dccp_mib);
+	if (dccp_statistics[1] == NULL)
+		goto out_free_one;
+
+	rc = 0;
+out:
+	return rc;
+out_free_one:
+	free_percpu(dccp_statistics[0]);
+	dccp_statistics[0] = NULL;
+	goto out;
+
+}
+
+static int thash_entries;
+module_param(thash_entries, int, 0444);
+MODULE_PARM_DESC(thash_entries, "Number of ehash buckets");
+
+int dccp_debug;
+module_param(dccp_debug, int, 0444);
+MODULE_PARM_DESC(dccp_debug, "Enable debug messages");
+
+static int __init dccp_init(void)
+{
+	unsigned long goal;
+	int ehash_order, bhash_order, i;
+	int rc = proto_register(&dccp_v4_prot, 1);
+
+	if (rc)
+		goto out;
+
+	dccp_hashinfo.bind_bucket_cachep = kmem_cache_create("dccp_bind_bucket",
+					       sizeof(struct inet_bind_bucket),
+					       0, SLAB_HWCACHE_ALIGN,
+					       NULL, NULL);
+	if (!dccp_hashinfo.bind_bucket_cachep)
+		goto out_proto_unregister;
+
+	/*
+	 * Size and allocate the main established and bind bucket
+	 * hash tables.
+	 *
+	 * The methodology is similar to that of the buffer cache.
+	 */
+	if (num_physpages >= (128 * 1024))
+		goal = num_physpages >> (21 - PAGE_SHIFT);
+	else
+		goal = num_physpages >> (23 - PAGE_SHIFT);
+
+	if (thash_entries)
+		goal = (thash_entries * sizeof(struct inet_ehash_bucket)) >> PAGE_SHIFT;
+	for (ehash_order = 0; (1UL << ehash_order) < goal; ehash_order++)
+		;
+	do {
+		dccp_hashinfo.ehash_size = (1UL << ehash_order) * PAGE_SIZE /
+					sizeof(struct inet_ehash_bucket);
+		dccp_hashinfo.ehash_size >>= 1;
+		while (dccp_hashinfo.ehash_size & (dccp_hashinfo.ehash_size - 1))
+			dccp_hashinfo.ehash_size--;
+		dccp_hashinfo.ehash = (struct inet_ehash_bucket *)
+			__get_free_pages(GFP_ATOMIC, ehash_order);
+	} while (!dccp_hashinfo.ehash && --ehash_order > 0);
+
+	if (!dccp_hashinfo.ehash) {
+		printk(KERN_CRIT "Failed to allocate DCCP "
+				 "established hash table\n");
+		goto out_free_bind_bucket_cachep;
+	}
+
+	for (i = 0; i < (dccp_hashinfo.ehash_size << 1); i++) {
+		rwlock_init(&dccp_hashinfo.ehash[i].lock);
+		INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].chain);
+	}
+
+	bhash_order = ehash_order;
+
+	do {
+		dccp_hashinfo.bhash_size = (1UL << bhash_order) * PAGE_SIZE /
+					sizeof(struct inet_bind_hashbucket);
+		if ((dccp_hashinfo.bhash_size > (64 * 1024)) && bhash_order > 0)
+			continue;
+		dccp_hashinfo.bhash = (struct inet_bind_hashbucket *)
+			__get_free_pages(GFP_ATOMIC, bhash_order);
+	} while (!dccp_hashinfo.bhash && --bhash_order >= 0);
+
+	if (!dccp_hashinfo.bhash) {
+		printk(KERN_CRIT "Failed to allocate DCCP bind hash table\n");
+		goto out_free_dccp_ehash;
+	}
+
+	for (i = 0; i < dccp_hashinfo.bhash_size; i++) {
+		spin_lock_init(&dccp_hashinfo.bhash[i].lock);
+		INIT_HLIST_HEAD(&dccp_hashinfo.bhash[i].chain);
+	}
+
+	if (init_dccp_v4_mibs())
+		goto out_free_dccp_bhash;
+
+	rc = -EAGAIN;
+	if (inet_add_protocol(&dccp_protocol, IPPROTO_DCCP))
+		goto out_free_dccp_v4_mibs;
+
+	inet_register_protosw(&dccp_v4_protosw);
+
+	rc = dccp_ctl_sock_init();
+	if (rc)
+		goto out_unregister_protosw;
+out:
+	return rc;
+out_unregister_protosw:
+	inet_unregister_protosw(&dccp_v4_protosw);
+	inet_del_protocol(&dccp_protocol, IPPROTO_DCCP);
+out_free_dccp_v4_mibs:
+	free_percpu(dccp_statistics[0]);
+	free_percpu(dccp_statistics[1]);
+	dccp_statistics[0] = dccp_statistics[1] = NULL;
+out_free_dccp_bhash:
+	free_pages((unsigned long)dccp_hashinfo.bhash, bhash_order);
+	dccp_hashinfo.bhash = NULL;
+out_free_dccp_ehash:
+	free_pages((unsigned long)dccp_hashinfo.ehash, ehash_order);
+	dccp_hashinfo.ehash = NULL;
+out_free_bind_bucket_cachep:
+	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
+	dccp_hashinfo.bind_bucket_cachep = NULL;
+out_proto_unregister:
+	proto_unregister(&dccp_v4_prot);
+	goto out;
+}
+
+static const char dccp_del_proto_err_msg[] __exitdata =
+	KERN_ERR "can't remove dccp net_protocol\n";
+
+static void __exit dccp_fini(void)
+{
+	dccp_ctl_sock_exit();
+
+	inet_unregister_protosw(&dccp_v4_protosw);
+
+	if (inet_del_protocol(&dccp_protocol, IPPROTO_DCCP) < 0)
+		printk(dccp_del_proto_err_msg);
+
+	/* Free the control endpoint.  */
+	sock_release(dccp_ctl_socket);
+
+	proto_unregister(&dccp_v4_prot);
+
+	kmem_cache_destroy(dccp_hashinfo.bind_bucket_cachep);
+}
+
+module_init(dccp_init);
+module_exit(dccp_fini);
+
+/* __stringify doesn't likes enums, so use SOCK_DCCP (6) value directly  */
+MODULE_ALIAS("net-pf-" __stringify(PF_INET) "-6");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@conectiva.com.br>");
+MODULE_DESCRIPTION("DCCP - Datagram Congestion Controlled Protocol");