path: root/net/dccp/ipv6.c

/*
 *	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/module.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/xfrm.h>

#include <net/addrconf.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/inet_sock.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/ip6_checksum.h>
#include <net/xfrm.h>
#include <net/secure_seq.h>

#include "dccp.h"
#include "ipv6.h"
#include "feat.h"

/* The per-net dccp.v6_ctl_sk is used for sending RSTs and ACKs */

static const struct inet_connection_sock_af_ops dccp_ipv6_mapped;
static const struct inet_connection_sock_af_ops dccp_ipv6_af_ops;

/* add pseudo-header to DCCP checksum stored in skb->csum */
static inline __sum16 dccp_v6_csum_finish(struct sk_buff *skb,
				      const struct in6_addr *saddr,
				      const struct in6_addr *daddr)
{
	return csum_ipv6_magic(saddr, daddr, skb->len, IPPROTO_DCCP, skb->csum);
}

static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct dccp_hdr *dh = dccp_hdr(skb);

	dccp_csum_outgoing(skb);
	dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &sk->sk_v6_daddr);
}

static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
{
	return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
					     ipv6_hdr(skb)->saddr.s6_addr32,
					     dccp_hdr(skb)->dccph_dport,
					     dccp_hdr(skb)->dccph_sport     );

}

static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
			u8 type, u8 code, int offset, __be32 info)
{
	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
	const struct dccp_hdr *dh;
	struct dccp_sock *dp;
	struct ipv6_pinfo *np;
	struct sock *sk;
	int err;
	__u64 seq;
	struct net *net = dev_net(skb->dev);

	/* Only need dccph_dport & dccph_sport which are the first
	 * 4 bytes in dccp header.
	 * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
	 */
	BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
	BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
	dh = (struct dccp_hdr *)(skb->data + offset);

	sk = __inet6_lookup_established(net, &dccp_hashinfo,
					&hdr->daddr, dh->dccph_dport,
					&hdr->saddr, ntohs(dh->dccph_sport),
					inet6_iif(skb));

	if (!sk) {
		ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
				   ICMP6_MIB_INERRORS);
		return;
	}

	if (sk->sk_state == DCCP_TIME_WAIT) {
		inet_twsk_put(inet_twsk(sk));
		return;
	}
	seq = dccp_hdr_seq(dh);
	if (sk->sk_state == DCCP_NEW_SYN_RECV)
		return dccp_req_err(sk, seq);

	bh_lock_sock(sk);
	if (sock_owned_by_user(sk))
		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);

	if (sk->sk_state == DCCP_CLOSED)
		goto out;

	dp = dccp_sk(sk);
	if ((1 << sk->sk_state) & ~(DCCPF_REQUESTING | DCCPF_LISTEN) &&
	    !between48(seq, dp->dccps_awl, dp->dccps_awh)) {
		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
		goto out;
	}

	np = inet6_sk(sk);

	if (type == NDISC_REDIRECT) {
		if (!sock_owned_by_user(sk)) {
			struct dst_entry *dst = __sk_dst_check(sk, np->dst_cookie);

			if (dst)
				dst->ops->redirect(dst, sk, skb);
		}
		goto out;
	}

	if (type == ICMPV6_PKT_TOOBIG) {
		struct dst_entry *dst = NULL;

		if (!ip6_sk_accept_pmtu(sk))
			goto out;

		if (sock_owned_by_user(sk))
			goto out;
		if ((1 << sk->sk_state) & (DCCPF_LISTEN | DCCPF_CLOSED