[DCCP]: Introduce DCCPv6

Still needs mucho polishing, specially in the checksum code, but works
just fine, inet_diag/iproute2 and all 8)

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

4 files changed, 1491 insertions, 1 deletions

diff --git a/net/dccp/Makefile b/net/dccp/Makefile
index 344a8da153fc90..87b27fff6e3b91 100644
--- a/net/dccp/Makefile
+++ b/net/dccp/Makefile
@@ -1,3 +1,7 @@
+obj-$(CONFIG_IPV6) += dccp_ipv6.o
+
+dccp_ipv6-y := ipv6.o
+
 obj-$(CONFIG_IP_DCCP) += dccp.o
 
 dccp-y := ccid.o input.o ipv4.o minisocks.o options.o output.o proto.o \
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
new file mode 100644
index 00000000000000..a7d2aee5b3aff9
--- /dev/null
+++ b/net/dccp/ipv6.c
@@ -0,0 +1,1438 @@
+/*
+ *	DCCP over IPv6
+ *	Linux INET6 implementation 
+ *
+ *	Based on net/dccp6/ipv6.c
+ *
+ *	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *
+ *	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/module.h>
+#include <linux/random.h>
+#include <linux/xfrm.h>
+
+#include <net/addrconf.h>
+#include <net/inet_common.h>
+#include <net/inet_hashtables.h>
+#include <net/inet6_connection_sock.h>
+#include <net/inet6_hashtables.h>
+#include <net/ip6_route.h>
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/xfrm.h>
+
+#include "dccp.h"
+#include "ipv6.h"
+
+static void dccp_v6_ctl_send_reset(struct sk_buff *skb);
+static void dccp_v6_reqsk_send_ack(struct sk_buff *skb,
+				   struct request_sock *req);
+static void dccp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb);
+
+static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
+
+static struct inet_connection_sock_af_ops dccp_ipv6_mapped;
+static struct inet_connection_sock_af_ops dccp_ipv6_af_ops;
+
+static int dccp_v6_get_port(struct sock *sk, unsigned short snum)
+{
+	return inet_csk_get_port(&dccp_hashinfo, sk, snum,
+				 inet6_csk_bind_conflict);
+}
+
+static void dccp_v6_hash(struct sock *sk)
+{
+	if (sk->sk_state != DCCP_CLOSED) {
+		if (inet_csk(sk)->icsk_af_ops == &dccp_ipv6_mapped) {
+			dccp_prot.hash(sk);
+			return;
+		}
+		local_bh_disable();
+		__inet6_hash(&dccp_hashinfo, sk);
+		local_bh_enable();
+	}
+}
+
+static inline u16 dccp_v6_check(struct dccp_hdr *dh, int len,
+				struct in6_addr *saddr, 
+				struct in6_addr *daddr, 
+				unsigned long base)
+{
+	return csum_ipv6_magic(saddr, daddr, len, IPPROTO_DCCP, base);
+}
+
+static __u32 dccp_v6_init_sequence(struct sock *sk, struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+
+	if (skb->protocol == htons(ETH_P_IPV6))
+		return secure_tcpv6_sequence_number(skb->nh.ipv6h->daddr.s6_addr32,
+						    skb->nh.ipv6h->saddr.s6_addr32,
+						    dh->dccph_dport,
+						    dh->dccph_sport);
+	else
+		return secure_dccp_sequence_number(skb->nh.iph->daddr,
+						   skb->nh.iph->saddr,
+						   dh->dccph_dport,
+						   dh->dccph_sport);
+}
+
+static int __dccp_v6_check_established(struct sock *sk, const __u16 lport,
+				       struct inet_timewait_sock **twp)
+{
+	struct inet_sock *inet = inet_sk(sk);
+	const struct ipv6_pinfo *np = inet6_sk(sk);
+	const struct in6_addr *daddr = &np->rcv_saddr;
+	const struct in6_addr *saddr = &np->daddr;
+	const int dif = sk->sk_bound_dev_if;
+	const u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
+	const unsigned int hash = inet6_ehashfn(daddr, inet->num,
+						saddr, inet->dport);
+	struct inet_ehash_bucket *head = inet_ehash_bucket(&dccp_hashinfo, hash);
+	struct sock *sk2;
+	const struct hlist_node *node;
+	struct inet_timewait_sock *tw;
+
+	prefetch(head->chain.first);
+	write_lock(&head->lock);
+
+	/* Check TIME-WAIT sockets first. */
+	sk_for_each(sk2, node, &(head + dccp_hashinfo.ehash_size)->chain) {
+		const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);
+
+		tw = inet_twsk(sk2);
+
+		if(*((__u32 *)&(tw->tw_dport))	== ports	 &&
+		   sk2->sk_family		== PF_INET6	 &&
+		   ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	 &&
+		   ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
+		   sk2->sk_bound_dev_if == sk->sk_bound_dev_if)
+			goto not_unique;
+	}
+	tw = NULL;
+
+	/* And established part... */
+	sk_for_each(sk2, node, &head->chain) {
+		if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif))
+			goto not_unique;
+	}
+
+	BUG_TRAP(sk_unhashed(sk));
+	__sk_add_node(sk, &head->chain);
+	sk->sk_hash = hash;
+	sock_prot_inc_use(sk->sk_prot);
+	write_unlock(&head->lock);
+
+	if (twp) {
+		*twp = tw;
+		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
+	} else if (tw) {
+		/* 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;
+}
+
+static inline u32 dccp_v6_port_offset(const struct sock *sk)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct ipv6_pinfo *np = inet6_sk(sk);
+
+	return secure_tcpv6_port_ephemeral(np->rcv_saddr.s6_addr32,
+					   np->daddr.s6_addr32,
+					   inet->dport);
+}
+
+static int dccp_v6_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 low = sysctl_local_port_range[0];
+ 		int high = sysctl_local_port_range[1];
+		int range = high - low;
+ 		int i;
+		int port;
+		static u32 hint;
+		u32 offset = hint + dccp_v6_port_offset(sk);
+		struct hlist_node *node;
+ 		struct inet_timewait_sock *tw = NULL;
+
+ 		local_bh_disable();
+		for (i = 1; i <= range; i++) {
+			port = low + (i + offset) % range;
+ 			head = &dccp_hashinfo.bhash[inet_bhashfn(port,
+						    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 == port) {
+ 					BUG_TRAP(!hlist_empty(&tb->owners));
+ 					if (tb->fastreuse >= 0)
+ 						goto next_port;
+ 					if (!__dccp_v6_check_established(sk,
+									 port,
+									 &tw))
+ 						goto ok;
+ 					goto next_port;
+ 				}
+ 			}
+
+ 			tb = inet_bind_bucket_create(dccp_hashinfo.bind_bucket_cachep,
+						     head, port);
+ 			if (!tb) {
+ 				spin_unlock(&head->lock);
+ 				break;
+ 			}
+ 			tb->fastreuse = -1;
+ 			goto ok;
+
+ 		next_port:
+ 			spin_unlock(&head->lock);
+ 		}
+ 		local_bh_enable();
+
+ 		return -EADDRNOTAVAIL;
+ok:
+		hint += i;
+
+ 		/* Head lock still held and bh's disabled */
+ 		inet_bind_hash(sk, tb, port);
+		if (sk_unhashed(sk)) {
+ 			inet_sk(sk)->sport = htons(port);
+ 			__inet6_hash(&dccp_hashinfo, sk);
+ 		}
+ 		spin_unlock(&head->lock);
+
+ 		if (tw) {
+ 			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) {
+		__inet6_hash(&dccp_hashinfo, sk);
+		spin_unlock_bh(&head->lock);
+		return 0;
+	} else {
+		spin_unlock(&head->lock);
+		/* No definite answer... Walk to established hash table */
+		ret = __dccp_v6_check_established(sk, snum, NULL);
+out:
+		local_bh_enable();
+		return ret;
+	}
+}
+
+static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 
+			   int addr_len)
+{
+	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
+	struct inet_sock *inet = inet_sk(sk);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct dccp_sock *dp = dccp_sk(sk);
+	struct in6_addr *saddr = NULL, *final_p = NULL, final;
+	struct flowi fl;
+	struct dst_entry *dst;
+	int addr_type;
+	int err;
+
+	dp->dccps_role = DCCP_ROLE_CLIENT;
+
+	if (addr_len < SIN6_LEN_RFC2133) 
+		return -EINVAL;
+
+	if (usin->sin6_family != AF_INET6) 
+		return -EAFNOSUPPORT;
+
+	memset(&fl, 0, sizeof(fl));
+
+	if (np->sndflow) {
+		fl.fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
+		IP6_ECN_flow_init(fl.fl6_flowlabel);
+		if (fl.fl6_flowlabel & IPV6_FLOWLABEL_MASK) {
+			struct ip6_flowlabel *flowlabel;
+			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
+			if (flowlabel == NULL)
+				return -EINVAL;
+			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
+			fl6_sock_release(flowlabel);
+		}
+	}
+
+	/*
+  	 *	connect() to INADDR_ANY means loopback (BSD'ism).
+  	 */
+  	
+  	if (ipv6_addr_any(&usin->sin6_addr))
+		usin->sin6_addr.s6_addr[15] = 0x1; 
+
+	addr_type = ipv6_addr_type(&usin->sin6_addr);
+
+	if(addr_type & IPV6_ADDR_MULTICAST)
+		return -ENETUNREACH;
+
+	if (addr_type & IPV6_ADDR_LINKLOCAL) {
+		if (addr_len >= sizeof(struct sockaddr_in6) &&
+		    usin->sin6_scope_id) {
+			/* If interface is set while binding, indices
+			 * must coincide.
+			 */
+			if (sk->sk_bound_dev_if &&
+			    sk->sk_bound_dev_if != usin->sin6_scope_id)
+				return -EINVAL;
+
+			sk->sk_bound_dev_if = usin->sin6_scope_id;
+		}
+
+		/* Connect to link-local address requires an interface */
+		if (!sk->sk_bound_dev_if)
+			return -EINVAL;
+	}
+
+	ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
+	np->flow_label = fl.fl6_flowlabel;
+
+	/*
+	 *	DCCP over IPv4
+	 */
+
+	if (addr_type == IPV6_ADDR_MAPPED) {
+		u32 exthdrlen = dp->dccps_ext_header_len;
+		struct sockaddr_in sin;
+
+		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");
+
+		if (__ipv6_only_sock(sk))
+			return -ENETUNREACH;
+
+		sin.sin_family = AF_INET;
+		sin.sin_port = usin->sin6_port;
+		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];
+
+		inet_csk(sk)->icsk_af_ops = &dccp_ipv6_mapped;
+		sk->sk_backlog_rcv = dccp_v4_do_rcv;
+
+		err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
+
+		if (err) {
+			dp->dccps_ext_header_len = exthdrlen;
+			inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
+			sk->sk_backlog_rcv = dccp_v6_do_rcv;
+			goto failure;
+		} else {
+			ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000FFFF),
+				      inet->saddr);
+			ipv6_addr_set(&np->rcv_saddr, 0, 0, htonl(0x0000FFFF),
+				      inet->rcv_saddr);
+		}
+
+		return err;
+	}
+
+	if (!ipv6_addr_any(&np->rcv_saddr))
+		saddr = &np->rcv_saddr;
+
+	fl.proto = IPPROTO_DCCP;
+	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
+	ipv6_addr_copy(&fl.fl6_src, saddr ? saddr : &np->saddr);
+	fl.oif = sk->sk_bound_dev_if;
+	fl.fl_ip_dport = usin->sin6_port;
+	fl.fl_ip_sport = inet->sport;
+
+	if (np->opt && np->opt->srcrt) {
+		struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
+		ipv6_addr_copy(&final, &fl.fl6_dst);
+		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
+		final_p = &final;
+	}
+
+	err = ip6_dst_lookup(sk, &dst, &fl);
+	if (err)
+		goto failure;
+	if (final_p)
+		ipv6_addr_copy(&fl.fl6_dst, final_p);
+
+	if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
+		goto failure;
+
+	if (saddr == NULL) {
+		saddr = &fl.fl6_src;
+		ipv6_addr_copy(&np->rcv_saddr, saddr);
+	}
+
+	/* set the source address */
+	ipv6_addr_copy(&np->saddr, saddr);
+	inet->rcv_saddr = LOOPBACK4_IPV6;
+
+	ip6_dst_store(sk, dst, NULL);
+
+	dp->dccps_ext_header_len = 0;
+	if (np->opt)
+		dp->dccps_ext_header_len = np->opt->opt_flen + np->opt->opt_nflen;
+
+	inet->dport = usin->sin6_port;
+
+	dccp_set_state(sk, DCCP_REQUESTING);
+	err = dccp_v6_hash_connect(sk);
+	if (err)
+		goto late_failure;
+	/* FIXME */
+#if 0
+	dp->dccps_gar = secure_dccp_v6_sequence_number(np->saddr.s6_addr32,
+						       np->daddr.s6_addr32,
+						       inet->sport,
+						       inet->dport);
+#endif
+	err = dccp_connect(sk);
+	if (err)
+		goto late_failure;
+
+	return 0;
+
+late_failure:
+	dccp_set_state(sk, DCCP_CLOSED);
+	__sk_dst_reset(sk);
+failure:
+	inet->dport = 0;
+	sk->sk_route_caps = 0;
+	return err;
+}
+
+static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+			int type, int code, int offset, __u32 info)
+{
+	struct ipv6hdr *hdr = (struct ipv6hdr *)skb->data;
+	const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+	struct ipv6_pinfo *np;
+	struct sock *sk;
+	int err;
+	__u64 seq;
+
+	sk = inet6_lookup(&dccp_hashinfo, &hdr->daddr, dh->dccph_dport,
+			  &hdr->saddr, dh->dccph_sport, skb->dev->ifindex);
+
+	if (sk == NULL) {
+		ICMP6_INC_STATS_BH(__in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
+		return;
+	}
+
+	if (sk->sk_state == DCCP_TIME_WAIT) {
+		inet_twsk_put((struct inet_timewait_sock *)sk);
+		return;
+	}
+
+	bh_lock_sock(sk);
+	if (sock_owned_by_user(sk))
+		NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
+
+	if (sk->sk_state == DCCP_CLOSED)
+		goto out;
+
+	np = inet6_sk(sk);
+
+	if (type == ICMPV6_PKT_TOOBIG) {
+		struct dccp_sock *dp = dccp_sk(sk);
+		struct dst_entry *dst = NULL;
+
+		if (sock_owned_by_user(sk))
+			goto out;
+		if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED))
+			goto out;
+
+		/* icmp should have updated the destination cache entry */
+		dst = __sk_dst_check(sk, np->dst_cookie);
+
+		if (dst == NULL) {
+			struct inet_sock *inet = inet_sk(sk);
+			struct flowi fl;
+
+			/* BUGGG_FUTURE: Again, it is not clear how
+			   to handle rthdr case. Ignore this complexity
+			   for now.
+			 */
+			memset(&fl, 0, sizeof(fl));
+			fl.proto = IPPROTO_DCCP;
+			ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
+			ipv6_addr_copy(&fl.fl6_src, &np->saddr);
+			fl.oif = sk->sk_bound_dev_if;
+			fl.fl_ip_dport = inet->dport;
+			fl.fl_ip_sport = inet->sport;
+
+			if ((err = ip6_dst_lookup(sk, &dst, &fl))) {
+				sk->sk_err_soft = -err;
+				goto out;
+			}
+
+			if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
+				sk->sk_err_soft = -err;
+				goto out;
+			}
+
+		} else
+			dst_hold(dst);
+
+		if (dp->dccps_pmtu_cookie > dst_mtu(dst)) {
+			dccp_sync_mss(sk, dst_mtu(dst));
+		} /* else let the usual retransmit timer handle it */
+		dst_release(dst);
+		goto out;
+	}
+
+	icmpv6_err_convert(type, code, &err);
+
+	seq = DCCP_SKB_CB(skb)->dccpd_seq;
+	/* Might be for an request_sock */
+	switch (sk->sk_state) {
+		struct request_sock *req, **prev;
+	case DCCP_LISTEN:
+		if (sock_owned_by_user(sk))
+			goto out;
+
+		req = inet6_csk_search_req(sk, &prev, dh->dccph_dport,
+					   &hdr->daddr, &hdr->saddr,
+					   inet6_iif(skb));
+		if (!req)
+			goto out;
+
+		/* ICMPs are not backlogged, hence we cannot get
+		 * an established socket here.
+		 */
+		BUG_TRAP(req->sk == NULL);
+
+		if (seq != dccp_rsk(req)->dreq_iss) {
+			NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
+			goto out;
+		}
+
+		inet_csk_reqsk_queue_drop(sk, req, prev);
+		goto out;
+
+	case DCCP_REQUESTING:
+	case DCCP_RESPOND:  /* Cannot happen.
+			       It can, it SYNs are crossed. --ANK */ 
+		if (!sock_owned_by_user(sk)) {
+			DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+			sk->sk_err = err;
+			/*
+			 * Wake people up to see the error
+			 * (see connect in sock.c)
+			 */
+			sk->sk_error_report(sk);
+
+			dccp_done(sk);
+		} else
+			sk->sk_err_soft = err;
+		goto out;
+	}
+
+	if (!sock_owned_by_user(sk) && np->recverr) {
+		sk->sk_err = err;
+		sk->sk_error_report(sk);
+	} else
+		sk->sk_err_soft = err;
+
+out:
+	bh_unlock_sock(sk);
+	sock_put(sk);
+}
+
+
+static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
+				 struct dst_entry *dst)
+{
+	struct inet6_request_sock *ireq6 = inet6_rsk(req);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct sk_buff *skb;
+	struct ipv6_txoptions *opt = NULL;
+	struct in6_addr *final_p = NULL, final;
+	struct flowi fl;
+	int err = -1;
+
+	memset(&fl, 0, sizeof(fl));
+	fl.proto = IPPROTO_DCCP;
+	ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
+	ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
+	fl.fl6_flowlabel = 0;
+	fl.oif = ireq6->iif;
+	fl.fl_ip_dport = inet_rsk(req)->rmt_port;
+	fl.fl_ip_sport = inet_sk(sk)->sport;
+
+	if (dst == NULL) {
+		opt = np->opt;
+		if (opt == NULL &&
+		    np->rxopt.bits.osrcrt == 2 &&
+		    ireq6->pktopts) {
+			struct sk_buff *pktopts = ireq6->pktopts;
+			struct inet6_skb_parm *rxopt = IP6CB(pktopts);
+			if (rxopt->srcrt)
+				opt = ipv6_invert_rthdr(sk,
+					(struct ipv6_rt_hdr *)(pktopts->nh.raw +
+							       rxopt->srcrt));
+		}
+
+		if (opt && opt->srcrt) {
+			struct rt0_hdr *rt0 = (struct rt0_hdr *)opt->srcrt;
+			ipv6_addr_copy(&final, &fl.fl6_dst);
+			ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
+			final_p = &final;
+		}
+
+		err = ip6_dst_lookup(sk, &dst, &fl);
+		if (err)
+			goto done;
+		if (final_p)
+			ipv6_addr_copy(&fl.fl6_dst, final_p);
+		if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
+			goto done;
+	}
+
+	skb = dccp_make_response(sk, dst, req);
+	if (skb != NULL) {
+		struct dccp_hdr *dh = dccp_hdr(skb);
+		dh->dccph_checksum = dccp_v6_check(dh, skb->len,
+						   &ireq6->loc_addr,
+						   &ireq6->rmt_addr,
+						   csum_partial((char *)dh,
+								skb->len,
+								skb->csum));
+		ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
+		err = ip6_xmit(sk, skb, &fl, opt, 0);
+		if (err == NET_XMIT_CN)
+			err = 0;
+	}
+
+done:
+        if (opt && opt != np->opt)
+		sock_kfree_s(sk, opt, opt->tot_len);
+	return err;
+}
+
+static void dccp_v6_reqsk_destructor(struct request_sock *req)
+{
+	if (inet6_rsk(req)->pktopts != NULL)
+		kfree_skb(inet6_rsk(req)->pktopts);
+}
+
+static struct request_sock_ops dccp6_request_sock_ops = {
+	.family		= AF_INET6,
+	.obj_size	= sizeof(struct dccp6_request_sock),
+	.rtx_syn_ack	= dccp_v6_send_response,
+	.send_ack	= dccp_v6_reqsk_send_ack,
+	.destructor	= dccp_v6_reqsk_destructor,
+	.send_reset	= dccp_v6_ctl_send_reset,
+};
+
+static void dccp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct dccp_hdr *dh = dccp_hdr(skb);
+
+	dh->dccph_checksum = csum_ipv6_magic(&np->saddr, &np->daddr,
+					     len, IPPROTO_DCCP, 
+					     csum_partial((char *)dh,
+							  dh->dccph_doff << 2,
+							  skb->csum));
+}
+
+static void dccp_v6_ctl_send_reset(struct sk_buff *rxskb)
+{
+	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 flowi fl;
+	u64 seqno;
+
+	if (rxdh->dccph_type == DCCP_PKT_RESET)
+		return;
+
+	if (!ipv6_unicast_destination(rxskb))
+		return; 
+
+	/*
+	 * We need to grab some memory, and put together an RST,
+	 * and then put it into the queue to be sent.
+	 */
+
+	skb = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) +
+			dccp_hdr_reset_len, GFP_ATOMIC);
+	if (skb == NULL) 
+	  	return;
+
+	skb_reserve(skb, MAX_HEADER + sizeof(struct ipv6hdr) +
+		    dccp_hdr_reset_len);
+
+	skb->h.raw = skb_push(skb, dccp_hdr_reset_len);
+	dh = dccp_hdr(skb);
+	memset(dh, 0, dccp_hdr_reset_len);
+
+	/* Swap the send and the receive. */
+	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);
+
+	memset(&fl, 0, sizeof(fl));
+	ipv6_addr_copy(&fl.fl6_dst, &rxskb->nh.ipv6h->saddr);
+	ipv6_addr_copy(&fl.fl6_src, &rxskb->nh.ipv6h->daddr);
+	dh->dccph_checksum = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
+					     sizeof(*dh), IPPROTO_DCCP,
+					     skb->csum);
+	fl.proto = IPPROTO_DCCP;
+	fl.oif = inet6_iif(rxskb);
+	fl.fl_ip_dport = dh->dccph_dport;
+	fl.fl_ip_sport = dh->dccph_sport;
+
+	/* sk = NULL, but it is safe for now. RST socket required. */
+	if (!ip6_dst_lookup(NULL, &skb->dst, &fl)) {
+		if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
+			ip6_xmit(NULL, skb, &fl, NULL, 0);
+			DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
+			DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
+			return;
+		}
+	}
+
+	kfree_skb(skb);
+}
+
+static void dccp_v6_ctl_send_ack(struct sk_buff *rxskb)
+{
+	struct flowi fl;
+	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;
+
+	skb = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) +
+			dccp_hdr_ack_len, GFP_ATOMIC);
+	if (skb == NULL)
+		return;
+
+	skb_reserve(skb, MAX_HEADER + sizeof(struct ipv6hdr) +
+			 dccp_hdr_ack_len);
+
+	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);
+
+	memset(&fl, 0, sizeof(fl));
+	ipv6_addr_copy(&fl.fl6_dst, &rxskb->nh.ipv6h->saddr);
+	ipv6_addr_copy(&fl.fl6_src, &rxskb->nh.ipv6h->daddr);
+
+	/* FIXME: calculate checksum, IPv4 also should... */
+
+	fl.proto = IPPROTO_DCCP;
+	fl.oif = inet6_iif(rxskb);
+	fl.fl_ip_dport = dh->dccph_dport;
+	fl.fl_ip_sport = dh->dccph_sport;
+
+	if (!ip6_dst_lookup(NULL, &skb->dst, &fl)) {
+		if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
+			ip6_xmit(NULL, skb, &fl, NULL, 0);
+			DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
+			return;
+		}
+	}
+
+	kfree_skb(skb);
+}
+
+static void dccp_v6_reqsk_send_ack(struct sk_buff *skb,
+				   struct request_sock *req)
+{
+	dccp_v6_ctl_send_ack(skb);
+}
+
+static struct sock *dccp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	const struct ipv6hdr *iph = skb->nh.ipv6h;
+	struct sock *nsk;
+	struct request_sock **prev;
+	/* Find possible connection requests. */
+	struct request_sock *req = inet6_csk_search_req(sk, &prev,
+							dh->dccph_sport,
+							&iph->saddr,
+							&iph->daddr,
+							inet6_iif(skb));
+	if (req != NULL)
+		return dccp_check_req(sk, skb, req, prev);
+
+	nsk = __inet6_lookup_established(&dccp_hashinfo,
+					 &iph->saddr, dh->dccph_sport,
+					 &iph->daddr, ntohs(dh->dccph_dport),
+					 inet6_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;
+}
+
+static int dccp_v6_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;
+	struct inet6_request_sock *ireq6;
+	struct ipv6_pinfo *np = inet6_sk(sk);
+ 	const __u32 service = dccp_hdr_request(skb)->dccph_req_service;
+	struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
+	__u8 reset_code = DCCP_RESET_CODE_TOO_BUSY;
+
+	if (skb->protocol == htons(ETH_P_IP))
+		return dccp_v4_conn_request(sk, skb);
+
+	if (!ipv6_unicast_destination(skb))
+		goto drop; 
+
+	if (dccp_bad_service_code(sk, service)) {
+		reset_code = DCCP_RESET_CODE_BAD_SERVICE_CODE;
+		goto drop;
+ 	}
+	/*
+	 *	There are no SYN attacks on IPv6, yet...	
+	 */
+	if (inet_csk_reqsk_queue_is_full(sk))
+		goto drop;		
+
+	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
+		goto drop;
+
+	req = inet6_reqsk_alloc(sk->sk_prot->rsk_prot);
+	if (req == NULL)
+		goto drop;
+
+	/* FIXME: process options */
+
+	dccp_openreq_init(req, &dp, skb);
+
+	ireq6 = inet6_rsk(req);
+	ireq = inet_rsk(req);
+	ipv6_addr_copy(&ireq6->rmt_addr, &skb->nh.ipv6h->saddr);
+	ipv6_addr_copy(&ireq6->loc_addr, &skb->nh.ipv6h->daddr);
+	req->rcv_wnd	= 100; /* Fake, option parsing will get the
+				  right value */
+	ireq6->pktopts	= NULL;
+
+	if (ipv6_opt_accepted(sk, skb) ||
+	    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
+	    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
+		atomic_inc(&skb->users);
+		ireq6->pktopts = skb;
+	}
+	ireq6->iif = sk->sk_bound_dev_if;
+
+	/* So that link locals have meaning */
+	if (!sk->sk_bound_dev_if &&
+	    ipv6_addr_type(&ireq6->rmt_addr) & IPV6_ADDR_LINKLOCAL)
+		ireq6->iif = inet6_iif(skb);
+
+	/* 
+	 * 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	   = dcb->dccpd_seq;
+	dreq->dreq_iss	   = dccp_v6_init_sequence(sk, skb);
+	dreq->dreq_service = service;
+
+	if (dccp_v6_send_response(sk, req, NULL))
+		goto drop_and_free;
+
+	inet6_csk_reqsk_queue_hash_add(sk, req, DCCP_TIMEOUT_INIT);
+	return 0;
+
+drop_and_free:
+	reqsk_free(req);
+drop:
+	DCCP_INC_STATS_BH(DCCP_MIB_ATTEMPTFAILS);
+	dcb->dccpd_reset_code = reset_code;
+	return -1;
+}
+
+static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
+					      struct sk_buff *skb,
+					      struct request_sock *req,
+					      struct dst_entry *dst)
+{
+	struct inet6_request_sock *ireq6 = inet6_rsk(req);
+	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
+	struct inet_sock *newinet;
+	struct dccp_sock *newdp;
+	struct dccp6_sock *newdp6;
+	struct sock *newsk;
+	struct ipv6_txoptions *opt;
+
+	if (skb->protocol == htons(ETH_P_IP)) {
+		/*
+		 *	v6 mapped
+		 */
+
+		newsk = dccp_v4_request_recv_sock(sk, skb, req, dst);
+		if (newsk == NULL) 
+			return NULL;
+
+		newdp6 = (struct dccp6_sock *)newsk;
+		newdp = dccp_sk(newsk);
+		newinet = inet_sk(newsk);
+		newinet->pinet6 = &newdp6->inet6;
+		newnp = inet6_sk(newsk);
+
+		memcpy(newnp, np, sizeof(struct ipv6_pinfo));
+
+		ipv6_addr_set(&newnp->daddr, 0, 0, htonl(0x0000FFFF),
+			      newinet->daddr);
+
+		ipv6_addr_set(&newnp->saddr, 0, 0, htonl(0x0000FFFF),
+			      newinet->saddr);
+
+		ipv6_addr_copy(&newnp->rcv_saddr, &newnp->saddr);
+
+		inet_csk(newsk)->icsk_af_ops = &dccp_ipv6_mapped;
+		newsk->sk_backlog_rcv = dccp_v4_do_rcv;
+		newnp->pktoptions  = NULL;
+		newnp->opt	   = NULL;
+		newnp->mcast_oif   = inet6_iif(skb);
+		newnp->mcast_hops  = skb->nh.ipv6h->hop_limit;
+
+		/*
+		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
+		 * here, dccp_create_openreq_child now does this for us, see the comment in
+		 * that function for the gory details. -acme
+		 */
+
+		/* It is tricky place. Until this moment IPv4 tcp
+		   worked with IPv6 icsk.icsk_af_ops.
+		   Sync it now.
+		 */
+		dccp_sync_mss(newsk, newdp->dccps_pmtu_cookie);
+
+		return newsk;
+	}
+
+	opt = np->opt;
+
+	if (sk_acceptq_is_full(sk))
+		goto out_overflow;
+
+	if (np->rxopt.bits.osrcrt == 2 &&
+	    opt == NULL && ireq6->pktopts) {
+		struct inet6_skb_parm *rxopt = IP6CB(ireq6->pktopts);
+		if (rxopt->srcrt)
+			opt = ipv6_invert_rthdr(sk,
+				(struct ipv6_rt_hdr *)(ireq6->pktopts->nh.raw +
+						       rxopt->srcrt));
+	}
+
+	if (dst == NULL) {
+		struct in6_addr *final_p = NULL, final;
+		struct flowi fl;
+
+		memset(&fl, 0, sizeof(fl));
+		fl.proto = IPPROTO_DCCP;
+		ipv6_addr_copy(&fl.fl6_dst, &ireq6->rmt_addr);
+		if (opt && opt->srcrt) {
+			struct rt0_hdr *rt0 = (struct rt0_hdr *) opt->srcrt;
+			ipv6_addr_copy(&final, &fl.fl6_dst);
+			ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
+			final_p = &final;
+		}
+		ipv6_addr_copy(&fl.fl6_src, &ireq6->loc_addr);
+		fl.oif = sk->sk_bound_dev_if;
+		fl.fl_ip_dport = inet_rsk(req)->rmt_port;
+		fl.fl_ip_sport = inet_sk(sk)->sport;
+
+		if (ip6_dst_lookup(sk, &dst, &fl))
+			goto out;
+
+		if (final_p)
+			ipv6_addr_copy(&fl.fl6_dst, final_p);
+
+		if ((xfrm_lookup(&dst, &fl, sk, 0)) < 0)
+			goto out;
+	} 
+
+	newsk = dccp_create_openreq_child(sk, req, skb);
+	if (newsk == NULL)
+		goto out;
+
+	/*
+	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
+	 * count here, dccp_create_openreq_child now does this for us, see the
+	 * comment in that function for the gory details. -acme
+	 */
+
+	ip6_dst_store(newsk, dst, NULL);
+	newsk->sk_route_caps = dst->dev->features &
+		~(NETIF_F_IP_CSUM | NETIF_F_TSO);
+
+	newdp6 = (struct dccp6_sock *)newsk;
+	newinet = inet_sk(newsk);
+	newinet->pinet6 = &newdp6->inet6;
+	newdp = dccp_sk(newsk);
+	newnp = inet6_sk(newsk);
+
+	memcpy(newnp, np, sizeof(struct ipv6_pinfo));
+
+	ipv6_addr_copy(&newnp->daddr, &ireq6->rmt_addr);
+	ipv6_addr_copy(&newnp->saddr, &ireq6->loc_addr);
+	ipv6_addr_copy(&newnp->rcv_saddr, &ireq6->loc_addr);
+	newsk->sk_bound_dev_if = ireq6->iif;
+
+	/* Now IPv6 options... 
+
+	   First: no IPv4 options.
+	 */
+	newinet->opt = NULL;
+
+	/* Clone RX bits */
+	newnp->rxopt.all = np->rxopt.all;
+
+	/* Clone pktoptions received with SYN */
+	newnp->pktoptions = NULL;
+	if (ireq6->pktopts != NULL) {
+		newnp->pktoptions = skb_clone(ireq6->pktopts, GFP_ATOMIC);
+		kfree_skb(ireq6->pktopts);
+		ireq6->pktopts = NULL;
+		if (newnp->pktoptions)
+			skb_set_owner_r(newnp->pktoptions, newsk);
+	}
+	newnp->opt	  = NULL;
+	newnp->mcast_oif  = inet6_iif(skb);
+	newnp->mcast_hops = skb->nh.ipv6h->hop_limit;
+
+	/* Clone native IPv6 options from listening socket (if any)
+
+	   Yes, keeping reference count would be much more clever,
+	   but we make one more one thing there: reattach optmem
+	   to newsk.
+	 */
+	if (opt) {
+		newnp->opt = ipv6_dup_options(newsk, opt);
+		if (opt != np->opt)
+			sock_kfree_s(sk, opt, opt->tot_len);
+	}
+
+	newdp->dccps_ext_header_len = 0;
+	if (newnp->opt)
+		newdp->dccps_ext_header_len = newnp->opt->opt_nflen +
+					      newnp->opt->opt_flen;
+
+	dccp_sync_mss(newsk, dst_mtu(dst));
+
+	newinet->daddr = newinet->saddr = newinet->rcv_saddr = LOOPBACK4_IPV6;
+
+	__inet6_hash(&dccp_hashinfo, newsk);
+	inet_inherit_port(&dccp_hashinfo, sk, newsk);
+
+	return newsk;
+
+out_overflow:
+	NET_INC_STATS_BH(LINUX_MIB_LISTENOVERFLOWS);
+out:
+	NET_INC_STATS_BH(LINUX_MIB_LISTENDROPS);
+	if (opt && opt != np->opt)
+		sock_kfree_s(sk, opt, opt->tot_len);
+	dst_release(dst);
+	return NULL;
+}
+
+/* The socket must have it's spinlock held when we get
+ * here.
+ *
+ * We have a potential double-lock case here, so even when
+ * doing backlog processing we use the BH locking scheme.
+ * This is because we cannot sleep with the original spinlock
+ * held.
+ */
+static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct sk_buff *opt_skb = NULL;
+
+	/* Imagine: socket is IPv6. IPv4 packet arrives,
+	   goes to IPv4 receive handler and backlogged.
+	   From backlog it always goes here. Kerboom...
+	   Fortunately, dccp_rcv_established and rcv_established
+	   handle them correctly, but it is not case with
+	   dccp_v6_hnd_req and dccp_v6_ctl_send_reset().   --ANK
+	 */
+
+	if (skb->protocol == htons(ETH_P_IP))
+		return dccp_v4_do_rcv(sk, skb);
+
+	if (sk_filter(sk, skb, 0))
+		goto discard;
+
+	/*
+	 *	socket locking is here for SMP purposes as backlog rcv
+	 *	is currently called with bh processing disabled.
+	 */
+
+	/* Do Stevens' IPV6_PKTOPTIONS.
+
+	   Yes, guys, it is the only place in our code, where we
+	   may make it not affecting IPv4.
+	   The rest of code is protocol independent,
+	   and I do not like idea to uglify IPv4.
+
+	   Actually, all the idea behind IPV6_PKTOPTIONS
+	   looks not very well thought. For now we latch
+	   options, received in the last packet, enqueued
+	   by tcp. Feel free to propose better solution.
+	                                       --ANK (980728)
+	 */
+	if (np->rxopt.all)
+		opt_skb = skb_clone(skb, GFP_ATOMIC);
+
+	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
+		if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
+			goto reset;
+		return 0;
+	}
+
+	if (sk->sk_state == DCCP_LISTEN) { 
+		struct sock *nsk = dccp_v6_hnd_req(sk, skb);
+		if (!nsk)
+			goto discard;
+
+		/*
+		 * Queue it on the new socket if the new socket is active,
+		 * otherwise we just shortcircuit this and continue with
+		 * the new socket..
+		 */
+ 		if(nsk != sk) {
+			if (dccp_child_process(sk, nsk, skb))
+				goto reset;
+			if (opt_skb)
+				__kfree_skb(opt_skb);
+			return 0;
+		}
+	}
+
+	if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
+		goto reset;
+	return 0;
+
+reset:
+	dccp_v6_ctl_send_reset(skb);
+discard:
+	if (opt_skb)
+		__kfree_skb(opt_skb);
+	kfree_skb(skb);
+	return 0;
+}
+
+static int dccp_v6_rcv(struct sk_buff **pskb, unsigned int *nhoffp)
+{
+	const struct dccp_hdr *dh;
+	struct sk_buff *skb = *pskb;
+	struct sock *sk;
+	int rc;
+
+	/* Step 1: Check header basics: */
+
+	if (dccp_invalid_packet(skb))
+		goto discard_it;
+
+	dh = dccp_hdr(skb);
+
+	DCCP_SKB_CB(skb)->dccpd_seq  = dccp_hdr_seq(skb);
+	DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
+
+	if (dccp_packet_without_ack(skb))
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = DCCP_PKT_WITHOUT_ACK_SEQ;
+	else
+		DCCP_SKB_CB(skb)->dccpd_ack_seq = dccp_hdr_ack_seq(skb);
+
+	/* Step 2:
+	 * 	Look up flow ID in table and get corresponding socket */
+	sk = __inet6_lookup(&dccp_hashinfo, &skb->nh.ipv6h->saddr,
+			    dh->dccph_sport,
+			    &skb->nh.ipv6h->daddr, ntohs(dh->dccph_dport),
+			    inet6_iif(skb));
+	/* 
+	 * Step 2:
+	 * 	If no socket ...
+	 *		Generate Reset(No Connection) unless P.type == Reset
+	 *		Drop packet and return
+	 */
+	if (sk == NULL)
+		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)
+                goto do_time_wait;
+
+	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
+		goto discard_and_relse;
+
+	if (sk_filter(sk, skb, 0))
+		goto discard_and_relse;
+
+	skb->dev = NULL;
+
+	bh_lock_sock(sk);
+	rc = 0;
+	if (!sock_owned_by_user(sk))
+		rc = dccp_v6_do_rcv(sk, skb);
+	else
+		sk_add_backlog(sk, skb);
+	bh_unlock_sock(sk);
+
+	sock_put(sk);
+	return rc ? -1 : 0;
+
+no_dccp_socket:
+	if (!xfrm6_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_v6_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 struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
+	.queue_xmit	=	inet6_csk_xmit,
+	.send_check	=	dccp_v6_send_check,
+	.rebuild_header	=	inet6_sk_rebuild_header,
+	.conn_request	=	dccp_v6_conn_request,
+	.syn_recv_sock	=	dccp_v6_request_recv_sock,
+	.net_header_len	=	sizeof(struct ipv6hdr),
+	.setsockopt	=	ipv6_setsockopt,
+	.getsockopt	=	ipv6_getsockopt,
+	.addr2sockaddr	=	inet6_csk_addr2sockaddr,
+	.sockaddr_len	=	sizeof(struct sockaddr_in6)
+};
+
+/*
+ *	DCCP over IPv4 via INET6 API
+ */
+static struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
+	.queue_xmit	=	ip_queue_xmit,
+	.send_check	=	dccp_v4_send_check,
+	.rebuild_header	=	inet_sk_rebuild_header,
+	.conn_request	=	dccp_v6_conn_request,
+	.syn_recv_sock	=	dccp_v6_request_recv_sock,
+	.net_header_len	=	sizeof(struct iphdr),
+	.setsockopt	=	ipv6_setsockopt,
+	.getsockopt	=	ipv6_getsockopt,
+	.addr2sockaddr	=	inet6_csk_addr2sockaddr,
+	.sockaddr_len	=	sizeof(struct sockaddr_in6)
+};
+
+/* NOTE: A lot of things set to zero explicitly by call to
+ *       sk_alloc() so need not be done here.
+ */
+static int dccp_v6_init_sock(struct sock *sk)
+{
+	int err = dccp_v4_init_sock(sk);
+
+	if (err == 0)
+		inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
+
+	return err;
+}
+
+static int dccp_v6_destroy_sock(struct sock *sk)
+{
+	dccp_v4_destroy_sock(sk);
+	return inet6_destroy_sock(sk);
+}
+
+static struct proto dccp_v6_prot = {
+	.name			= "DCCPv6",
+	.owner			= THIS_MODULE,
+	.close			= dccp_close,
+	.connect		= dccp_v6_connect,
+	.disconnect		= dccp_disconnect,
+	.ioctl			= dccp_ioctl,
+	.init			= dccp_v6_init_sock,
+	.setsockopt		= dccp_setsockopt,
+	.getsockopt		= dccp_getsockopt,
+	.sendmsg		= dccp_sendmsg,
+	.recvmsg		= dccp_recvmsg,
+	.backlog_rcv		= dccp_v6_do_rcv,
+	.hash			= dccp_v6_hash,
+	.unhash			= dccp_unhash,
+	.accept			= inet_csk_accept,
+	.get_port		= dccp_v6_get_port,
+	.shutdown		= dccp_shutdown,
+	.destroy		= dccp_v6_destroy_sock,
+	.orphan_count		= &dccp_orphan_count,
+	.max_header		= MAX_DCCP_HEADER,
+	.obj_size		= sizeof(struct dccp6_sock),
+	.rsk_prot		= &dccp6_request_sock_ops,
+	.twsk_obj_size		= sizeof(struct dccp6_timewait_sock),
+};
+
+static struct inet6_protocol dccp_v6_protocol = {
+	.handler	=	dccp_v6_rcv,
+	.err_handler	=	dccp_v6_err,
+	.flags		=	INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
+};
+
+static struct proto_ops inet6_dccp_ops = {
+	.family		= PF_INET6,
+	.owner		= THIS_MODULE,
+	.release	= inet6_release,
+	.bind		= inet6_bind,
+	.connect	= inet_stream_connect,
+	.socketpair	= sock_no_socketpair,
+	.accept		= inet_accept,
+	.getname	= inet6_getname,
+	.poll		= dccp_poll,
+	.ioctl		= inet6_ioctl,
+	.listen		= inet_dccp_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,
+};
+
+static struct inet_protosw dccp_v6_protosw = {
+	.type		= SOCK_DCCP,
+	.protocol	= IPPROTO_DCCP,
+	.prot		= &dccp_v6_prot,
+	.ops		= &inet6_dccp_ops,
+	.capability	= -1,
+};
+
+static int __init dccp_v6_init(void)
+{
+	int err = proto_register(&dccp_v6_prot, 1);
+
+	if (err != 0)
+		goto out;
+
+	err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
+	if (err != 0)
+		goto out_unregister_proto;
+
+	inet6_register_protosw(&dccp_v6_protosw);
+out:
+	return err;
+out_unregister_proto:
+	proto_unregister(&dccp_v6_prot);
+	goto out;
+}
+
+static void __exit dccp_v6_exit(void)
+{
+	inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
+	inet6_unregister_protosw(&dccp_v6_protosw);
+	proto_unregister(&dccp_v6_prot);
+}
+
+module_init(dccp_v6_init);
+module_exit(dccp_v6_exit);
+
+/*
+ * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
+ * values directly, Also cover the case where the protocol is not specified,
+ * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
+ */
+MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-33-type-6");
+MODULE_ALIAS("net-pf-" __stringify(PF_INET6) "-proto-0-type-6");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnaldo Carvalho de Melo <acme@mandriva.com>");
+MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");
diff --git a/net/dccp/ipv6.h b/net/dccp/ipv6.h
new file mode 100644
index 00000000000000..e4d4e930927020
--- /dev/null
+++ b/net/dccp/ipv6.h
@@ -0,0 +1,37 @@
+#ifndef _DCCP_IPV6_H
+#define _DCCP_IPV6_H
+/*
+ *  net/dccp/ipv6.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *
+ *	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/ipv6.h>
+
+struct dccp6_sock {
+	struct dccp_sock  dccp;
+	/*
+	 * ipv6_pinfo has to be the last member of dccp6_sock,
+	 * see inet6_sk_generic.
+	 */
+	struct ipv6_pinfo inet6;
+};
+
+struct dccp6_request_sock {
+	struct dccp_request_sock  dccp;
+	struct inet6_request_sock inet6;
+};
+
+struct dccp6_timewait_sock {
+	struct inet_timewait_sock   inet;
+	struct inet6_timewait_sock  tw6;
+};
+
+#endif /* _DCCP_IPV6_H */
diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
index 5c767b5e9a52de..29261fc198e761 100644
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -52,7 +52,18 @@ void dccp_time_wait(struct sock *sk, int state, int timeo)
 	if (tw != NULL) {
 		const struct inet_connection_sock *icsk = inet_csk(sk);
 		const int rto = (icsk->icsk_rto << 2) - (icsk->icsk_rto >> 1);
-
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+		if (tw->tw_family == PF_INET6) {
+			const struct ipv6_pinfo *np = inet6_sk(sk);
+			struct inet6_timewait_sock *tw6;
+
+			tw->tw_ipv6_offset = inet6_tw_offset(sk->sk_prot);
+			tw6 = inet6_twsk((struct sock *)tw);
+			ipv6_addr_copy(&tw6->tw_v6_daddr, &np->daddr);
+			ipv6_addr_copy(&tw6->tw_v6_rcv_saddr, &np->rcv_saddr);
+			tw->tw_ipv6only = np->ipv6only;
+		}
+#endif
 		/* Linkage updates. */
 		__inet_twsk_hashdance(tw, sk, &dccp_hashinfo);