Auto-update from upstream

1 files changed, 1356 insertions, 0 deletions

diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
new file mode 100644
index 000000000000..3fc75dbee4b8
--- /dev/null
+++ b/net/dccp/ipv4.c
@@ -0,0 +1,1356 @@
+/*
+ *  net/dccp/ipv4.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
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/dccp.h>
+#include <linux/icmp.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/random.h>
+
+#include <net/icmp.h>
+#include <net/inet_hashtables.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/xfrm.h>
+
+#include "ccid.h"
+#include "dccp.h"
+
+struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
+	.lhash_lock	= RW_LOCK_UNLOCKED,
+	.lhash_users	= ATOMIC_INIT(0),
+	.lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
+	.portalloc_lock	= SPIN_LOCK_UNLOCKED,
+	.port_rover	= 1024 - 1,
+};
+
+EXPORT_SYMBOL_GPL(dccp_hashinfo);
+
+static int dccp_v4_get_port(struct sock *sk, const unsigned short snum)
+{
+	return inet_csk_get_port(&dccp_hashinfo, sk, snum);
+}
+
+static void dccp_v4_hash(struct sock *sk)
+{
+	inet_hash(&dccp_hashinfo, sk);
+}
+
+static void dccp_v4_unhash(struct sock *sk)
+{
+	inet_unhash(&dccp_hashinfo, sk);
+}
+
+/* called with local bh disabled */
+static int __dccp_v4_check_established(struct sock *sk, const __u16 lport,
+				      struct inet_timewait_sock **twp)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	const u32 daddr = inet->rcv_saddr;
+	const u32 saddr = inet->daddr;
+	const int dif = sk->sk_bound_dev_if;
+	INET_ADDR_COOKIE(acookie, saddr, daddr)
+	const __u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
+	const int hash = inet_ehashfn(daddr, lport, saddr, inet->dport,
+				      dccp_hashinfo.ehash_size);
+	struct inet_ehash_bucket *head = &dccp_hashinfo.ehash[hash];
+	const struct sock *sk2;
+	const struct hlist_node *node;
+	struct inet_timewait_sock *tw;
+
+	write_lock(&head->lock);
+
+	/* Check TIME-WAIT sockets first. */
+	sk_for_each(sk2, node, &(head + dccp_hashinfo.ehash_size)->chain) {
+		tw = inet_twsk(sk2);
+
+		if (INET_TW_MATCH(sk2, acookie, saddr, daddr, ports, dif))
+			goto not_unique;
+	}
+	tw = NULL;
+
+	/* And established part... */
+	sk_for_each(sk2, node, &head->chain) {
+		if (INET_MATCH(sk2, acookie, saddr, daddr, ports, dif))
+			goto not_unique;
+	}
+
+	/* Must record num and sport now. Otherwise we will see
+	 * in hash table socket with a funny identity. */
+	inet->num = lport;
+	inet->sport = htons(lport);
+	sk->sk_hashent = hash;
+	BUG_TRAP(sk_unhashed(sk));
+	__sk_add_node(sk, &head->chain);
+	sock_prot_inc_use(sk->sk_prot);
+	write_unlock(&head->lock);
+
+	if (twp != NULL) {
+		*twp = tw;
+		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+	} else if (tw != NULL) {
+		/* Silly. Should hash-dance instead... */
+		inet_twsk_deschedule(tw, &dccp_death_row);
+		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+
+		inet_twsk_put(tw);
+	}
+
+	return 0;
+
+not_unique:
+	write_unlock(&head->lock);
+	return -EADDRNOTAVAIL;
+}
+
+/*
+ * Bind a port for a connect operation and hash it.
+ */
+static int dccp_v4_hash_connect(struct sock *sk)
+{
+	const unsigned short snum = inet_sk(sk)->num;
+ 	struct inet_bind_hashbucket *head;
+ 	struct inet_bind_bucket *tb;
+	int ret;
+
+ 	if (snum == 0) {
+ 		int rover;
+ 		int low = sysctl_local_port_range[0];
+ 		int high = sysctl_local_port_range[1];
+ 		int remaining = (high - low) + 1;
+		struct hlist_node *node;
+ 		struct inet_timewait_sock *tw = NULL;
+
+ 		local_bh_disable();
+
+ 		/* TODO. Actually it is not so bad idea to remove
+ 		 * dccp_hashinfo.portalloc_lock before next submission to
+		 * Linus.
+ 		 * As soon as we touch this place at all it is time to think.
+ 		 *
+ 		 * Now it protects single _advisory_ variable
+		 * dccp_hashinfo.port_rover, hence it is mostly useless.
+ 		 * Code will work nicely if we just delete it, but
+ 		 * I am afraid in contented case it will work not better or
+ 		 * even worse: another cpu just will hit the same bucket
+ 		 * and spin there.
+ 		 * So some cpu salt could remove both contention and
+ 		 * memory pingpong. Any ideas how to do this in a nice way?
+ 		 */
+ 		spin_lock(&dccp_hashinfo.portalloc_lock);
+ 		rover = dccp_hashinfo.port_rover;
+
+ 		do {
+ 			rover++;
+ 			if ((rover < low) || (rover > high))
+ 				rover = low;
+ 			head = &dccp_hashinfo.bhash[inet_bhashfn(rover,
+						    dccp_hashinfo.bhash_size)];
+ 			spin_lock(&head->lock);
+
+ 			/* Does not bother with rcv_saddr checks,
+ 			 * because the established check is already
+ 			 * unique enough.
+ 			 */
+			inet_bind_bucket_for_each(tb, node, &head->chain) {
+ 				if (tb->port == rover) {
+ 					BUG_TRAP(!hlist_empty(&tb->owners));
+ 					if (tb->fastreuse >= 0)
+ 						goto next_port;
+ 					if (!__dccp_v4_check_established(sk,
+									 rover,
+									 &tw))
+ 						goto ok;
+ 					goto next_port;
+ 				}
+ 			}
+
+ 			tb = inet_bind_bucket_create(dccp_hashinfo.bind_bucket_cachep,
+						     head, rover);
+ 			if (tb == NULL) {
+ 				spin_unlock(&head->lock);
+ 				break;
+ 			}
+ 			tb->fastreuse = -1;
+ 			goto ok;
+
+ 		next_port:
+ 			spin_unlock(&head->lock);
+ 		} while (--remaining > 0);
+ 		dccp_hashinfo.port_rover = rover;
+ 		spin_unlock(&dccp_hashinfo.portalloc_lock);
+
+ 		local_bh_enable();
+
+ 		return -EADDRNOTAVAIL;
+
+ok:
+ 		/* All locks still held and bhs disabled */
+ 		dccp_hashinfo.port_rover = rover;
+ 		spin_unlock(&dccp_hashinfo.portalloc_lock);
+
+ 		inet_bind_hash(sk, tb, rover);
+		if (sk_unhashed(sk)) {
+ 			inet_sk(sk)->sport = htons(rover);
+ 			__inet_hash(&dccp_hashinfo, sk, 0);
+ 		}
+ 		spin_unlock(&head->lock);
+
+ 		if (tw != NULL) {
+ 			inet_twsk_deschedule(tw, &dccp_death_row);
+ 			inet_twsk_put(tw);
+ 		}
+
+		ret = 0;
+		goto out;
+ 	}
+
+ 	head = &dccp_hashinfo.bhash[inet_bhashfn(snum,
+						 dccp_hashinfo.bhash_size)];
+ 	tb   = inet_csk(sk)->icsk_bind_hash;
+	spin_lock_bh(&head->lock);
+	if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
+		__inet_hash(&dccp_hashinfo, sk, 0);
+		spin_unlock_bh(&head->lock);
+		return 0;
+	} else {
+		spin_unlock(&head->lock);
+		/* No definite answer... Walk to established hash table */
+		ret = __dccp_v4_check_established(sk, snum, NULL);
+out:
+		local_bh_enable();
+		return ret;
+	}
+}
+
+static int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr,
+			   int addr_len)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	struct dccp_sock *dp = dccp_sk(sk);
+	const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
+	struct rtable *rt;
+	u32 daddr, nexthop;
+	int tmp;
+	int err;
+
+	dp->dccps_role = DCCP_ROLE_CLIENT;
+
+	if (addr_len < sizeof(struct sockaddr_in))
+		return -EINVAL;
+
+	if (usin->sin_family != AF_INET)
+		return -EAFNOSUPPORT;
+
+	nexthop = daddr = usin->sin_addr.s_addr;
+	if (inet->opt != NULL && inet->opt->srr) {
+		if (daddr == 0)
+			return -EINVAL;
+		nexthop = inet->opt->faddr;
+	}
+
+	tmp = ip_route_connect(&rt, nexthop, inet->saddr,
+			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
+			       IPPROTO_DCCP,
+			       inet->sport, usin->sin_port, sk);
+	if (tmp < 0)
+		return tmp;
+
+	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
+		ip_rt_put(rt);
+		return -ENETUNREACH;
+	}
+
+	if (inet->opt == NULL || !inet->opt->srr)
+		daddr = rt->rt_dst;
+
+	if (inet->saddr == 0)
+		inet->saddr = rt->rt_src;
+	inet->rcv_saddr = inet->saddr;
+
+	inet->dport = usin->sin_port;
+	inet->daddr = daddr;
+
+	dp->dccps_ext_header_len = 0;
+	if (inet->opt != NULL)
+		dp->dccps_ext_header_len = inet->opt->optlen;
+	/*
+	 * Socket identity is still unknown (sport may be zero).
+	 * However we set state to DCCP_REQUESTING and not releasing socket
+	 * lock select source port, enter ourselves into the hash tables and
+	 * complete initialization after this.
+	 */
+	dccp_set_state(sk, DCCP_REQUESTING);
+	err = dccp_v4_hash_connect(sk);
+	if (err != 0)
+		goto failure;
+
+	err = ip_route_newports(&rt, inet->sport, inet->dport, sk);
+	if (err != 0)
+		goto failure;
+
+	/* OK, now commit destination to socket.  */
+	sk_setup_caps(sk, &rt->u.dst);
+
+	dp->dccps_gar =
+		dp->dccps_iss = secure_dccp_sequence_number(inet->saddr,
+							    inet->daddr,
+							    inet->sport,
+							    usin->sin_port);
+	dccp_update_gss(sk, dp->dccps_iss);
+
+	/*
+	 * SWL and AWL are initially adjusted so that they are not less than
+	 * the initial Sequence Numbers received and sent, respectively:
+	 *	SWL := max(GSR + 1 - floor(W/4), ISR),
+	 *	AWL := max(GSS - W' + 1, ISS).
+	 * These adjustments MUST be applied only at the beginning of the
+	 * connection.
+	 */
+	dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));
+
+	inet->id = dp->dccps_iss ^ jiffies;
+
+	err = dccp_connect(sk);
+	rt = NULL;
+	if (err != 0)
+		goto failure;
+out:
+	return err;
+failure:
+	/*
+	 * This unhashes the socket and releases the local port, if necessary.
+	 */
+	dccp_set_state(sk, DCCP_CLOSED);
+	ip_rt_put(rt);
+	sk->sk_route_caps = 0;
+	inet->dport = 0;
+	goto out;
+}
+
+/*
+ * This routine does path mtu discovery as defined in RFC1191.
+ */
+static inline void dccp_do_pmtu_discovery(struct sock *sk,
+					  const struct iphdr *iph,
+					  u32 mtu)
+{
+	struct dst_entry *dst;
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct dccp_sock *dp = dccp_sk(sk);
+
+	/* We are not interested in DCCP_LISTEN and request_socks (RESPONSEs
+	 * send out by Linux are always < 576bytes so they should go through
+	 * unfragmented).
+	 */
+	if (sk->sk_state == DCCP_LISTEN)
+		return;
+
+	/* We don't check in the destentry if pmtu discovery is forbidden
+	 * on this route. We just assume that no packet_to_big packets
+	 * are send back when pmtu discovery is not active.
+     	 * There is a small race when the user changes this flag in the
+	 * route, but I think that's acceptable.
+	 */
+	if ((dst = __sk_dst_check(sk, 0)) == NULL)
+		return;
+
+	dst->ops->update_pmtu(dst, mtu);
+
+	/* Something is about to be wrong... Remember soft error
+	 * for the case, if this connection will not able to recover.
+	 */
+	if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
+		sk->sk_err_soft = EMSGSIZE;
+
+	mtu = dst_mtu(dst);
+
+	if (inet->pmtudisc != IP_PMTUDISC_DONT &&
+	    dp->dccps_pmtu_cookie > mtu) {
+		dccp_sync_mss(sk, mtu);
+
+		/*
+		 * From: draft-ietf-dccp-spec-11.txt
+		 *
+		 *	DCCP-Sync packets are the best choice for upward
+		 *	probing, since DCCP-Sync probes do not risk application
+		 *	data loss.
+		 */
+		dccp_send_sync(sk, dp->dccps_gsr, DCCP_PKT_SYNC);
+	} /* else let the usual retransmit timer handle it */
+}
+
+static void dccp_v4_ctl_send_ack(struct sk_buff *rxskb)
+{
+	int err;
+	struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
+	const int dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
+				     sizeof(struct dccp_hdr_ext) +
+				     sizeof(struct dccp_hdr_ack_bits);
+	struct sk_buff *skb;
+
+	if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
+		return;
+
+	skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
+	if (skb == NULL)
+		return;
+
+	/* Reserve space for headers. */
+	skb_reserve(skb, MAX_DCCP_HEADER);
+
+	skb->dst = dst_clone(rxskb->dst);
+
+	skb->h.raw = skb_push(skb, dccp_hdr_ack_len);
+	dh = dccp_hdr(skb);
+	memset(dh, 0, dccp_hdr_ack_len);
+
+	/* Build DCCP header and checksum it. */
+	dh->dccph_type	   = DCCP_PKT_ACK;
+	dh->dccph_sport	   = rxdh->dccph_dport;
+	dh->dccph_dport	   = rxdh->dccph_sport;
+	dh->dccph_doff	   = dccp_hdr_ack_len / 4;
+	dh->dccph_x	   = 1;
+
+	dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
+	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
+			 DCCP_SKB_CB(rxskb)->dccpd_seq);
+
+	bh_lock_sock(dccp_ctl_socket->sk);
+	err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
+				    rxskb->nh.iph->daddr,
+				    rxskb->nh.iph->saddr, NULL);
+	bh_unlock_sock(dccp_ctl_socket->sk);
+
+	if (err == NET_XMIT_CN || err == 0) {
+		DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
+		DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
+	}
+}
+
+static void dccp_v4_reqsk_send_ack(struct sk_buff *skb,
+				   struct request_sock *req)
+{
+	dccp_v4_ctl_send_ack(skb);
+}
+
+static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
+				 struct dst_entry *dst)
+{
+	int err = -1;
+	struct sk_buff *skb;
+
+	/* First, grab a route. */
+	
+	if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
+		goto out;
+
+	skb = dccp_make_response(sk, dst, req);
+	if (skb != NULL) {
+		const struct inet_request_sock *ireq = inet_rsk(req);
+
+		err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
+					    ireq->rmt_addr,
+					    ireq->opt);
+		if (err == NET_XMIT_CN)
+			err = 0;
+	}
+
+out:
+	dst_release(dst);
+	return err;
+}
+
+/*
+ * 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.
+ * After adjustment header points to the first 8 bytes of the tcp header. We
+ * need to find the appropriate port.
+ *
+ * The locking strategy used here is very "optimistic". When someone else
+ * accesses the socket the ICMP is just dropped and for some paths there is no
+ * check at all. A more general error queue to queue errors for later handling
+ * is probably better.
+ */
+void dccp_v4_err(struct sk_buff *skb, u32 info)
+{
+	const struct iphdr *iph = (struct iphdr *)skb->data;
+	const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data +
+							(iph->ihl << 2));
+	struct dccp_sock *dp;
+	struct inet_sock *inet;
+	const int type = skb->h.icmph->type;
+	const int code = skb->h.icmph->code;
+	struct sock *sk;
+	__u64 seq;
+	int err;
+
+	if (skb->len < (iph->ihl << 2) + 8) {
+		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+		return;
+	}
+
+	sk = inet_lookup(&dccp_hashinfo, iph->daddr, dh->dccph_dport,
+			 iph->saddr, dh->dccph_sport, inet_iif(skb));
+	if (sk == NULL) {
+		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+		return;
+	}
+
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		inet_twsk_put((struct inet_timewait_sock *)sk);
+		return;
+	}
+
+	bh_lock_sock(sk);
+	/* If too many ICMPs get dropped on busy
+	 * servers this needs to be solved differently.
+	 */
+	if (sock_owned_by_user(sk))
+		NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
+
+	if (sk->sk_state == DCCP_CLOSED)
+		goto out;
+
+	dp = dccp_sk(sk);
+	seq = dccp_hdr_seq(skb);
+	if (sk->sk_state != DCCP_LISTEN &&
+	    !between48(seq, dp->dccps_swl, dp->dccps_swh)) {
+		NET_INC_STATS(LINUX_MIB_OUTOFWINDOWICMPS);
+		goto out;
+	}
+
+	switch (type) {
+	case ICMP_SOURCE_QUENCH:
+		/* Just silently ignore these. */
+		goto out;
+	case ICMP_PARAMETERPROB:
+		err = EPROTO;
+		break;
+	case ICMP_DEST_UNREACH:
+		if (code > NR_ICMP_UNREACH)
+			goto out;
+
+		if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
+			if (!sock_owned_by_user(sk))
+				dccp_do_pmtu_discovery(sk, iph, info);
+			goto out;
+		}
+
+		err = icmp_err_convert[code].errno;
+		break;
+	case ICMP_TIME_EXCEEDED:
+		err = EHOSTUNREACH;
+		break;
+	default:
+		goto out;
+	}
+
+	switch (sk->sk_state) {
+		struct request_sock *req , **prev;
+	case DCCP_LISTEN:
+		if (sock_owned_by_user(sk))
+			goto out;
+		req = inet_csk_search_req(sk, &prev, dh->dccph_dport,
+					  iph->daddr, iph->saddr);
+		if (!req)
+			goto out;
+
+		/*
+		 * ICMPs are not backlogged, hence we cannot get an established
+		 * socket here.
+		 */
+		BUG_TRAP(!req->sk);
+
+		if (seq != dccp_rsk(req)->dreq_iss) {
+			NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
+			goto out;
+		}
+		/*
+		 * Still in RESPOND, just remove it silently.
+		 * There is no good way to pass the error to the newly
+		 * created socket, and POSIX does not want network
+		 * errors returned from accept().
+		 */
+		inet_csk_reqsk_queue_drop(sk, req, prev);
+		goto out;
+
+	case DCCP_REQUESTING:
+	case DCCP_RESPOND:
+		if (!sock_owned_by_user(sk)) {
+			DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+			sk->sk_err = err;
+
+			sk->sk_error_report(sk);
+
+			dccp_done(sk);
+		} else
+			sk->sk_err_soft = err;
+		goto out;
+	}
+
+	/* If we've already connected we will keep trying
+	 * until we time out, or the user gives up.
+	 *
+	 * rfc1122 4.2.3.9 allows to consider as hard errors
+	 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
+	 * but it is obsoleted by pmtu discovery).
+	 *
+	 * Note, that in modern internet, where routing is unreliable
+	 * and in each dark corner broken firewalls sit, sending random
+	 * errors ordered by their masters even this two messages finally lose
+	 * their original sense (even Linux sends invalid PORT_UNREACHs)
+	 *
+	 * Now we are in compliance with RFCs.
+	 *							--ANK (980905)
+	 */
+
+	inet = inet_sk(sk);
+	if (!sock_owned_by_user(sk) && inet->recverr) {
+		sk->sk_err = err;
+		sk->sk_error_report(sk);
+	} else /* Only an error on timeout */
+		sk->sk_err_soft = err;
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+int dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code)
+{
+	struct sk_buff *skb;
+	/*
+	 * FIXME: what if rebuild_header fails?
+	 * Should we be doing a rebuild_header here?
+	 */
+	int err = inet_sk_rebuild_header(sk);
+
+	if (err != 0)
+		return err;
+
+	skb = dccp_make_reset(sk, sk->sk_dst_cache, code);
+	if (skb != NULL) {
+		const struct dccp_sock *dp = dccp_sk(sk);
+		const struct inet_sock *inet = inet_sk(sk);
+
+		err = ip_build_and_send_pkt(skb, sk,
+					    inet->saddr, inet->daddr, NULL);
+		if (err == NET_XMIT_CN)
+			err = 0;
+
+		ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
+		ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
+	}
+
+	return err;
+}
+
+static inline u64 dccp_v4_init_sequence(const struct sock *sk,
+					const struct sk_buff *skb)
+{
+	return secure_dccp_sequence_number(skb->nh.iph->daddr,
+					   skb->nh.iph->saddr,
+					   dccp_hdr(skb)->dccph_dport,
+					   dccp_hdr(skb)->dccph_sport);
+}
+
+int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
+{
+	struct inet_request_sock *ireq;
+	struct dccp_sock dp;
+	struct request_sock *req;
+	struct dccp_request_sock *dreq;
+	const __u32 saddr = skb->nh.iph->saddr;
+	const __u32 daddr = skb->nh.iph->daddr;
+	struct dst_entry *dst = NULL;
+
+	/* Never answer to DCCP_PKT_REQUESTs send to broadcast or multicast */
+	if (((struct rtable *)skb->dst)->rt_flags &
+	    (RTCF_BROADCAST | RTCF_MULTICAST))
+		goto drop;
+
+	/*
+	 * TW buckets are converted to open requests without
+	 * limitations, they conserve resources and peer is
+	 * evidently real one.
+	 */
+	if (inet_csk_reqsk_queue_is_full(sk))
+		goto drop;
+
+	/*
+	 * Accept backlog is full. If we have already queued enough
+	 * of warm entries in syn queue, drop request. It is better than
+	 * clogging syn queue with openreqs with exponentially increasing
+	 * timeout.
+	 */
+	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
+		goto drop;
+
+	req = reqsk_alloc(sk->sk_prot->rsk_prot);
+	if (req == NULL)
+		goto drop;
+
+	/* FIXME: process options */
+
+	dccp_openreq_init(req, &dp, skb);
+
+	ireq = inet_rsk(req);
+	ireq->loc_addr = daddr;
+	ireq->rmt_addr = saddr;
+	/* FIXME: Merge Aristeu's option parsing code when ready */
+	req->rcv_wnd	= 100; /* Fake, option parsing will get the
+				  right value */
+	ireq->opt	= NULL;
+
+	/* 
+	 * Step 3: Process LISTEN state
+	 *
+	 * Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
+	 *
+	 * In fact we defer setting S.GSR, S.SWL, S.SWH to
+	 * dccp_create_openreq_child.
+	 */
+	dreq = dccp_rsk(req);
+	dreq->dreq_isr = DCCP_SKB_CB(skb)->dccpd_seq;
+	dreq->dreq_iss = dccp_v4_init_sequence(sk, skb);
+	dreq->dreq_service = dccp_hdr_request(skb)->dccph_req_service;
+
+	if (dccp_v4_send_response(sk, req, dst))
+		goto drop_and_free;
+
+	inet_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
+	return 0;
+
+drop_and_free:
+	/*
+	 * FIXME: should be reqsk_free after implementing req->rsk_ops
+	 */
+	__reqsk_free(req);
+drop:
+	DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+	return -1;
+}
+
+/*
+ * The three way handshake has completed - we got a valid ACK or DATAACK -
+ * now create the new socket.
+ *
+ * This is the equivalent of TCP's tcp_v4_syn_recv_sock
+ */
+struct sock *dccp_v4_request_recv_sock(struct sock *sk, struct sk_buff *skb,
+				       struct request_sock *req,
+				       struct dst_entry *dst)
+{
+	struct inet_request_sock *ireq;
+	struct inet_sock *newinet;
+	struct dccp_sock *newdp;
+	struct sock *newsk;
+
+	if (sk_acceptq_is_full(sk))
+		goto exit_overflow;
+
+	if (dst == NULL && (dst = inet_csk_route_req(sk, req)) == NULL)
+		goto exit;
+
+	newsk = dccp_create_openreq_child(sk, req, skb);
+	if (newsk == NULL)
+		goto exit;
+
+	sk_setup_caps(newsk, dst);
+
+	newdp		   = dccp_sk(newsk);
+	newinet		   = inet_sk(newsk);
+	ireq		   = inet_rsk(req);
+	newinet->daddr	   = ireq->rmt_addr;
+	newinet->rcv_saddr = ireq->loc_addr;
+	newinet->saddr	   = ireq->loc_addr;
+	newinet->opt	   = ireq->opt;
+	ireq->opt	   = NULL;
+	newinet->mc_index  = inet_iif(skb);
+	newinet->mc_ttl	   = skb->nh.iph->ttl;
+	newinet->id	   = jiffies;
+
+	dccp_sync_mss(newsk, dst_mtu(dst));
+
+	__inet_hash(&dccp_hashinfo, newsk, 0);
+	__inet_inherit_port(&dccp_hashinfo, sk, newsk);
+
+	return newsk;
+
+exit_overflow:
+	NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
+exit:
+	NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
+	dst_release(dst);
+	return NULL;
+}
+
+static struct sock *dccp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	const struct iphdr *iph = skb->nh.iph;
+	struct sock *nsk;
+	struct request_sock **prev;
+	/* Find possible connection requests. */
+	struct request_sock *req = inet_csk_search_req(sk, &prev,
+						       dh->dccph_sport,
+						       iph->saddr, iph->daddr);
+	if (req != NULL)
+		return dccp_check_req(sk, skb, req, prev);
+
+	nsk = __inet_lookup_established(&dccp_hashinfo,
+					iph->saddr, dh->dccph_sport,
+					iph->daddr, ntohs(dh->dccph_dport),
+					inet_iif(skb));
+	if (nsk != NULL) {
+		if (nsk->sk_state != DCCP_TIME_WAIT) {
+			bh_lock_sock(nsk);
+			return nsk;
+		}
+		inet_twsk_put((struct inet_timewait_sock *)nsk);
+		return NULL;
+	}
+
+	return sk;
+}
+
+int dccp_v4_checksum(const struct sk_buff *skb, const u32 saddr,
+		     const u32 daddr)
+{
+	const struct dccp_hdr* dh = dccp_hdr(skb);
+	int checksum_len;
+	u32 tmp;
+
+	if (dh->dccph_cscov == 0)
+		checksum_len = skb->len;
+	else {
+		checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
+		checksum_len = checksum_len < skb->len ? checksum_len :
+							 skb->len;
+	}
+
+	tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
+	return csum_tcpudp_magic(saddr, daddr, checksum_len,
+				 IPPROTO_DCCP, tmp);
+}
+
+static int dccp_v4_verify_checksum(struct sk_buff *skb,
+				   const u32 saddr, const u32 daddr)
+{
+	struct dccp_hdr *dh = dccp_hdr(skb);
+	int checksum_len;
+	u32 tmp;
+
+	if (dh->dccph_cscov == 0)
+		checksum_len = skb->len;
+	else {
+		checksum_len = (dh->dccph_cscov + dh->dccph_x) * sizeof(u32);
+		checksum_len = checksum_len < skb->len ? checksum_len :
+							 skb->len;
+	}
+	tmp = csum_partial((unsigned char *)dh, checksum_len, 0);
+	return csum_tcpudp_magic(saddr, daddr, checksum_len,
+				 IPPROTO_DCCP, tmp) == 0 ? 0 : -1;
+}
+
+static struct dst_entry* dccp_v4_route_skb(struct sock *sk,
+					   struct sk_buff *skb)
+{
+	struct rtable *rt;
+	struct flowi fl = { .oif = ((struct rtable *)skb->dst)->rt_iif,
+			    .nl_u = { .ip4_u =
+				      { .daddr = skb->nh.iph->saddr,
+					.saddr = skb->nh.iph->daddr,
+					.tos = RT_CONN_FLAGS(sk) } },
+			    .proto = sk->sk_protocol,
+			    .uli_u = { .ports =
+				       { .sport = dccp_hdr(skb)->dccph_dport,
+					 .dport = dccp_hdr(skb)->dccph_sport }
+			   	     }
+			  };
+
+	if (ip_route_output_flow(&rt, &fl, sk, 0)) {
+		IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
+		return NULL;
+	}
+
+	return &rt->u.dst;
+}
+
+static void dccp_v4_ctl_send_reset(struct sk_buff *rxskb)
+{
+	int err;
+	struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
+	const int dccp_hdr_reset_len = sizeof(struct dccp_hdr) +
+				       sizeof(struct dccp_hdr_ext) +
+				       sizeof(struct dccp_hdr_reset);
+	struct sk_buff *skb;
+	struct dst_entry *dst;
+	u64 seqno;
+
+	/* Never send a reset in response to a reset. */
+	if (rxdh->dccph_type == DCCP_PKT_RESET)
+		return;
+
+	if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
+		return;
+
+	dst = dccp_v4_route_skb(dccp_ctl_socket->sk, rxskb);
+	if (dst == NULL)
+		return;
+
+	skb = alloc_skb(MAX_DCCP_HEADER + 15, GFP_ATOMIC);
+	if (skb == NULL)
+		goto out;
+
+	/* Reserve space for headers. */
+	skb_reserve(skb, MAX_DCCP_HEADER);
+	skb->dst = dst_clone(dst);
+
+	skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
+	dh = dccp_hdr(skb);
+	memset(dh, 0, dccp_hdr_reset_len);
+
+	/* Build DCCP header and checksum it. */
+	dh->dccph_type	   = DCCP_PKT_RESET;
+	dh->dccph_sport	   = rxdh->dccph_dport;
+	dh->dccph_dport	   = rxdh->dccph_sport;
+	dh->dccph_doff	   = dccp_hdr_reset_len / 4;
+	dh->dccph_x	   = 1;
+	dccp_hdr_reset(skb)->dccph_reset_code =
+				DCCP_SKB_CB(rxskb)->dccpd_reset_code;
+
+	/* See "8.3.1. Abnormal Termination" in draft-ietf-dccp-spec-11 */
+	seqno = 0;
+	if (DCCP_SKB_CB(rxskb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
+		dccp_set_seqno(&seqno, DCCP_SKB_CB(rxskb)->dccpd_ack_seq + 1);
+
+	dccp_hdr_set_seq(dh, seqno);
+	dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
+			 DCCP_SKB_CB(rxskb)->dccpd_seq);
+
+	dh->dccph_checksum = dccp_v4_checksum(skb, rxskb->nh.iph->saddr,
+					      rxskb->nh.iph->daddr);
+
+	bh_lock_sock(dccp_ctl_socket->sk);
+	err = ip_build_and_send_pkt(skb, dccp_ctl_socket->sk,
+				    rxskb->nh.iph->daddr,
+				    rxskb->nh.iph->saddr, NULL);
+	bh_unlock_sock(dccp_ctl_socket->sk);
+
+	if (err == NET_XMIT_CN || err == 0) {
+		DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
+		DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
+	}
+out:
+	 dst_release(dst);
+}
+
+int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct dccp_hdr *dh = dccp_hdr(skb);
+
+	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
+		if (dccp_rcv_established(sk, skb, dh, skb->len))
+			goto reset;
+		return 0;
+	}
+
+	/*
+	 *  Step 3: Process LISTEN state
+	 *     If S.state == LISTEN,
+	 *	  If P.type == Request or P contains a valid Init Cookie
+	 *	  	option,
+	 *	     * Must scan the packet's options to check for an Init
+	 *		Cookie.  Only the Init Cookie is processed here,
+	 *		however; other options are processed in Step 8.  This
+	 *		scan need only be performed if the endpoint uses Init
+	 *		Cookies *
+	 *	     * Generate a new socket and switch to that socket *
+	 *	     Set S := new socket for this port pair
+	 *	     S.state = RESPOND
+	 *	     Choose S.ISS (initial seqno) or set from Init Cookie
+	 *	     Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init Cookie
+	 *	     Continue with S.state == RESPOND
+	 *	     * A Response packet will be generated in Step 11 *
+	 *	  Otherwise,
+	 *	     Generate Reset(No Connection) unless P.type == Reset
+	 *	     Drop packet and return
+	 *
+	 * NOTE: the check for the packet types is done in
+	 *	 dccp_rcv_state_process
+	 */
+	if (sk->sk_state == DCCP_LISTEN) {
+		struct sock *nsk = dccp_v4_hnd_req(sk, skb);
+
+		if (nsk == NULL)
+			goto discard;
+
+		if (nsk != sk) {
+			if (dccp_child_process(sk, nsk, skb))
+				goto reset;
+			return 0;
+		}
+	}
+
+	if (dccp_rcv_state_process(sk, skb, dh, skb->len))
+		goto reset;
+	return 0;
+
+reset:
+	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
+	dccp_v4_ctl_send_reset(skb);
+discard:
+	kfree_skb(skb);
+	return 0;
+}
+
+static inline int dccp_invalid_packet(struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh;
+
+	if (skb->pkt_type != PACKET_HOST)
+		return 1;
+
+	if (!pskb_may_pull(skb, sizeof(struct dccp_hdr))) {
+		LIMIT_NETDEBUG(KERN_WARNING "DCCP: pskb_may_pull failed\n");
+		return 1;
+	}
+
+	dh = dccp_hdr(skb);
+
+	/* If the packet type is not understood, drop packet and return */
+	if (dh->dccph_type >= DCCP_PKT_INVALID) {
+		LIMIT_NETDEBUG(KERN_WARNING "DCCP: invalid packet type\n");
+		return 1;
+	}
+
+	/*
+	 * If P.Data Offset is too small for packet type, or too large for
+	 * packet, drop packet and return
+	 */
+	if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
+		LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
+					    "too small 1\n",
+			       dh->dccph_doff);
+		return 1;
+	}
+
+	if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
+		LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.Data Offset(%u) "
+					    "too small 2\n",
+			       dh->dccph_doff);
+		return 1;
+	}
+
+	dh = dccp_hdr(skb);
+
+	/*
+	 * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
+	 * has short sequence numbers), drop packet and return
+	 */
+	if (dh->dccph_x == 0 &&
+	    dh->dccph_type != DCCP_PKT_DATA &&
+	    dh->dccph_type != DCCP_PKT_ACK &&
+	    dh->dccph_type != DCCP_PKT_DATAACK) {
+		LIMIT_NETDEBUG(KERN_WARNING "DCCP: P.type (%s) not Data, Ack "
+					    "nor DataAck and P.X == 0\n",
+			       dccp_packet_name(dh->dccph_type));
+		return 1;
+	}
+
+	/* If the header checksum is incorrect, drop packet and return */
+	if (dccp_v4_verify_checksum(skb, skb->nh.iph->saddr,
+				    skb->nh.iph->daddr) < 0) {
+		LIMIT_NETDEBUG(KERN_WARNING "DCCP: header checksum is "
+					    "incorrect\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+/* this is called when real data arrives */
+int dccp_v4_rcv(struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh;
+	struct sock *sk;
+	int rc;
+
+	/* Step 1: Check header basics: */
+
+	if (dccp_invalid_packet(skb))
+		goto discard_it;
+
+	dh = dccp_hdr(skb);
+#if 0
+	/*
+	 * Use something like this to simulate some DATA/DATAACK loss to test
+	 * dccp_ackpkts_add, you'll get something like this on a session that
+	 * sends 10 DATA/DATAACK packets:
+	 *
+	 * ackpkts_print: 281473596467422 |0,0|3,0|0,0|3,0|0,0|3,0|0,0|3,0|0,1|
+	 *
+	 * 0, 0 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == just this packet
+	 * 0, 1 means: DCCP_ACKPKTS_STATE_RECEIVED, RLE == two adjacent packets
+	 * 						   with the same state
+	 * 3, 0 means: DCCP_ACKPKTS_STATE_NOT_RECEIVED, RLE == just this packet
+	 *
+	 * So...
+	 *
+	 * 281473596467422 was received
+	 * 281473596467421 was not received
+	 * 281473596467420 was received
+	 * 281473596467419 was not received
+	 * 281473596467418 was received
+	 * 281473596467417 was not received
+	 * 281473596467416 was received
+	 * 281473596467415 was not received
+	 * 281473596467414 was received
+	 * 281473596467413 was received (this one was the 3way handshake
+	 * 				 RESPONSE)
+	 *
+	 */
+	if (dh->dccph_type == DCCP_PKT_DATA ||
+	    dh->dccph_type == DCCP_PKT_DATAACK) {
+		static int discard = 0;
+
+		if (discard) {
+			discard = 0;
+			goto discard_it;
+		}
+		discard = 1;
+	}
+#endif
+	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(skb);
+	DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
+
+	dccp_pr_debug("%8.8s "
+		      "src=%u.%u.%u.%u@%-5d "
+		      "dst=%u.%u.%u.%u@%-5d seq=%llu",
+		      dccp_packet_name(dh->dccph_type),
+		      NIPQUAD(skb->nh.iph->saddr), ntohs(dh->dccph_sport),
+		      NIPQUAD(skb->nh.iph->daddr), ntohs(dh->dccph_dport),
+		      (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
+
+	if (dccp_packet_without_ack(skb)) {
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
+		dccp_pr_debug_cat("\n");
+	} else {
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
+		dccp_pr_debug_cat(", ack=%llu\n",
+				  (unsigned long long)
+				  DCCP_SKB_CB(skb)->dccpd_ack_seq);
+	}
+
+	/* Step 2:
+	 * 	Look up flow ID in table and get corresponding socket */
+	sk = __inet_lookup(&dccp_hashinfo,
+			   skb->nh.iph->saddr, dh->dccph_sport,
+			   skb->nh.iph->daddr, ntohs(dh->dccph_dport),
+			   inet_iif(skb));
+
+	/* 
+	 * Step 2:
+	 * 	If no socket ...
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (sk == NULL) {
+		dccp_pr_debug("failed to look up flow ID in table and "
+			      "get corresponding socket\n");
+		goto no_dccp_socket;
+	}
+
+	/* 
+	 * Step 2:
+	 * 	... or S.state == TIMEWAIT,
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	       
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: "
+			      "do_time_wait\n");
+                goto do_time_wait;
+	}
+
+	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
+		dccp_pr_debug("xfrm4_policy_check failed\n");
+		goto discard_and_relse;
+	}
+
+        if (sk_filter(sk, skb, 0)) {
+		dccp_pr_debug("sk_filter failed\n");
+                goto discard_and_relse;
+	}
+
+	skb->dev = NULL;
+
+	bh_lock_sock(sk);
+	rc = 0;
+	if (!sock_owned_by_user(sk))
+		rc = dccp_v4_do_rcv(sk, skb);
+	else
+		sk_add_backlog(sk, skb);
+	bh_unlock_sock(sk);
+
+	sock_put(sk);
+	return rc;
+
+no_dccp_socket:
+	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
+		goto discard_it;
+	/*
+	 * Step 2:
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (dh->dccph_type != DCCP_PKT_RESET) {
+		DCCP_SKB_CB(skb)->dccpd_reset_code =
+					DCCP_RESET_CODE_NO_CONNECTION;
+		dccp_v4_ctl_send_reset(skb);
+	}
+
+discard_it:
+	/* Discard frame. */
+	kfree_skb(skb);
+	return 0;
+
+discard_and_relse:
+	sock_put(sk);
+	goto discard_it;
+
+do_time_wait:
+	inet_twsk_put((struct inet_timewait_sock *)sk);
+	goto no_dccp_socket;
+}
+
+static int dccp_v4_init_sock(struct sock *sk)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	static int dccp_ctl_socket_init = 1;
+
+	dccp_options_init(&dp->dccps_options);
+
+	if (dp->dccps_options.dccpo_send_ack_vector) {
+		dp->dccps_hc_rx_ackpkts =
+			dccp_ackpkts_alloc(DCCP_MAX_ACK_VECTOR_LEN,
+					   GFP_KERNEL);
+
+		if (dp->dccps_hc_rx_ackpkts == NULL)
+			return -ENOMEM;
+	}
+
+	/*
+	 * FIXME: We're hardcoding the CCID, and doing this at this point makes
+	 * the listening (master) sock get CCID control blocks, which is not
+	 * necessary, but for now, to not mess with the test userspace apps,
+	 * lets leave it here, later the real solution is to do this in a
+	 * setsockopt(CCIDs-I-want/accept). -acme
+	 */
+	if (likely(!dccp_ctl_socket_init)) {
+		dp->dccps_hc_rx_ccid = ccid_init(dp->dccps_options.dccpo_ccid,
+						 sk);
+		dp->dccps_hc_tx_ccid = ccid_init(dp->dccps_options.dccpo_ccid,
+						 sk);
+	    	if (dp->dccps_hc_rx_ccid == NULL ||
+		    dp->dccps_hc_tx_ccid == NULL) {
+			ccid_exit(dp->dccps_hc_rx_ccid, sk);
+			ccid_exit(dp->dccps_hc_tx_ccid, sk);
+			dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
+			dp->dccps_hc_rx_ackpkts = NULL;
+			dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
+			return -ENOMEM;
+		}
+	} else
+		dccp_ctl_socket_init = 0;
+
+	dccp_init_xmit_timers(sk);
+	inet_csk(sk)->icsk_rto = DCCP_TIMEOUT_INIT;
+	sk->sk_state = DCCP_CLOSED;
+	sk->sk_write_space = dccp_write_space;
+	dp->dccps_mss_cache = 536;
+	dp->dccps_role = DCCP_ROLE_UNDEFINED;
+
+	return 0;
+}
+
+static int dccp_v4_destroy_sock(struct sock *sk)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+
+	/*
+	 * DCCP doesn't use sk_qrite_queue, just sk_send_head
+	 * for retransmissions
+	 */
+	if (sk->sk_send_head != NULL) {
+		kfree_skb(sk->sk_send_head);
+		sk->sk_send_head = NULL;
+	}
+
+	/* Clean up a referenced DCCP bind bucket. */
+	if (inet_csk(sk)->icsk_bind_hash != NULL)
+		inet_put_port(&dccp_hashinfo, sk);
+
+	ccid_hc_rx_exit(dp->dccps_hc_rx_ccid, sk);
+	ccid_hc_tx_exit(dp->dccps_hc_tx_ccid, sk);
+	dccp_ackpkts_free(dp->dccps_hc_rx_ackpkts);
+	dp->dccps_hc_rx_ackpkts = NULL;
+	ccid_exit(dp->dccps_hc_rx_ccid, sk);
+	ccid_exit(dp->dccps_hc_tx_ccid, sk);
+	dp->dccps_hc_rx_ccid = dp->dccps_hc_tx_ccid = NULL;
+
+	return 0;
+}
+
+static void dccp_v4_reqsk_destructor(struct request_sock *req)
+{
+	kfree(inet_rsk(req)->opt);
+}
+
+static struct request_sock_ops dccp_request_sock_ops = {
+	.family		= PF_INET,
+	.obj_size	= sizeof(struct dccp_request_sock),
+	.rtx_syn_ack	= dccp_v4_send_response,
+	.send_ack	= dccp_v4_reqsk_send_ack,
+	.destructor	= dccp_v4_reqsk_destructor,
+	.send_reset	= dccp_v4_ctl_send_reset,
+};
+
+struct proto dccp_v4_prot = {
+	.name			= "DCCP",
+	.owner			= THIS_MODULE,
+	.close			= dccp_close,
+	.connect		= dccp_v4_connect,
+	.disconnect		= dccp_disconnect,
+	.ioctl			= dccp_ioctl,
+	.init			= dccp_v4_init_sock,
+	.setsockopt		= dccp_setsockopt,
+	.getsockopt		= dccp_getsockopt,
+	.sendmsg		= dccp_sendmsg,
+	.recvmsg		= dccp_recvmsg,
+	.backlog_rcv		= dccp_v4_do_rcv,
+	.hash			= dccp_v4_hash,
+	.unhash			= dccp_v4_unhash,
+	.accept			= inet_csk_accept,
+	.get_port		= dccp_v4_get_port,
+	.shutdown		= dccp_shutdown,
+	.destroy		= dccp_v4_destroy_sock,
+	.orphan_count		= &dccp_orphan_count,
+	.max_header		= MAX_DCCP_HEADER,
+	.obj_size		= sizeof(struct dccp_sock),
+	.rsk_prot		= &dccp_request_sock_ops,
+	.twsk_obj_size		= sizeof(struct inet_timewait_sock),
+};