tcp_ipv6.c 41.0 KB
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/*
 *	TCP over IPv6
 *	Linux INET6 implementation 
 *
 *	Authors:
 *	Pedro Roque		<roque@di.fc.ul.pt>	
 *
 *	$Id: tcp_ipv6.c,v 1.144 2002/02/01 22:01:04 davem Exp $
 *
 *	Based on: 
 *	linux/net/ipv4/tcp.c
 *	linux/net/ipv4/tcp_input.c
 *	linux/net/ipv4/tcp_output.c
 *
 *	Fixes:
 *	Hideaki YOSHIFUJI	:	sin6_scope_id support
 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
 *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
 *					a single port at the same time.
 *	YOSHIFUJI Hideaki @USAGI:	convert /proc/net/tcp6 to seq_file.
 *
 *	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/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/jiffies.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/jhash.h>
#include <linux/ipsec.h>
#include <linux/times.h>

#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/random.h>

#include <net/tcp.h>
#include <net/ndisc.h>
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#include <net/inet6_hashtables.h>
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#include <net/inet6_connection_sock.h>
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#include <net/ipv6.h>
#include <net/transp_v6.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/ip6_checksum.h>
#include <net/inet_ecn.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <net/addrconf.h>
#include <net/snmp.h>
#include <net/dsfield.h>
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#include <net/timewait_sock.h>
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#include <asm/uaccess.h>

#include <linux/proc_fs.h>
#include <linux/seq_file.h>

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/* Socket used for sending RSTs and ACKs */
static struct socket *tcp6_socket;

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static void	tcp_v6_send_reset(struct sk_buff *skb);
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static void	tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req);
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static void	tcp_v6_send_check(struct sock *sk, int len, 
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				  struct sk_buff *skb);

static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);

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static struct inet_connection_sock_af_ops ipv6_mapped;
static struct inet_connection_sock_af_ops ipv6_specific;
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static int tcp_v6_get_port(struct sock *sk, unsigned short snum)
{
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	return inet_csk_get_port(&tcp_hashinfo, sk, snum,
				 inet6_csk_bind_conflict);
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}

static void tcp_v6_hash(struct sock *sk)
{
	if (sk->sk_state != TCP_CLOSE) {
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		if (inet_csk(sk)->icsk_af_ops == &ipv6_mapped) {
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			tcp_prot.hash(sk);
			return;
		}
		local_bh_disable();
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		__inet6_hash(&tcp_hashinfo, sk);
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		local_bh_enable();
	}
}

static __inline__ u16 tcp_v6_check(struct tcphdr *th, int len,
				   struct in6_addr *saddr, 
				   struct in6_addr *daddr, 
				   unsigned long base)
{
	return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
}

static __u32 tcp_v6_init_sequence(struct sock *sk, struct sk_buff *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,
						    skb->h.th->dest,
						    skb->h.th->source);
	} else {
		return secure_tcp_sequence_number(skb->nh.iph->daddr,
						  skb->nh.iph->saddr,
						  skb->h.th->dest,
						  skb->h.th->source);
	}
}

static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr, 
			  int addr_len)
{
	struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
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 	struct inet_sock *inet = inet_sk(sk);
	struct inet_connection_sock *icsk = inet_csk(sk);
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	struct ipv6_pinfo *np = inet6_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
	struct in6_addr *saddr = NULL, *final_p = NULL, final;
	struct flowi fl;
	struct dst_entry *dst;
	int addr_type;
	int err;

	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;
	}

	if (tp->rx_opt.ts_recent_stamp &&
	    !ipv6_addr_equal(&np->daddr, &usin->sin6_addr)) {
		tp->rx_opt.ts_recent = 0;
		tp->rx_opt.ts_recent_stamp = 0;
		tp->write_seq = 0;
	}

	ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
	np->flow_label = fl.fl6_flowlabel;

	/*
	 *	TCP over IPv4
	 */

	if (addr_type == IPV6_ADDR_MAPPED) {
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		u32 exthdrlen = icsk->icsk_ext_hdr_len;
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		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];

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		icsk->icsk_af_ops = &ipv6_mapped;
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		sk->sk_backlog_rcv = tcp_v4_do_rcv;

		err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));

		if (err) {
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			icsk->icsk_ext_hdr_len = exthdrlen;
			icsk->icsk_af_ops = &ipv6_specific;
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			sk->sk_backlog_rcv = tcp_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_TCP;
	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);

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	if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
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		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;

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	sk->sk_gso_type = SKB_GSO_TCPV6;
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	__ip6_dst_store(sk, dst, NULL);
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	icsk->icsk_ext_hdr_len = 0;
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	if (np->opt)
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		icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
					  np->opt->opt_nflen);
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	tp->rx_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);

	inet->dport = usin->sin6_port;

	tcp_set_state(sk, TCP_SYN_SENT);
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	err = inet6_hash_connect(&tcp_death_row, sk);
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	if (err)
		goto late_failure;

	if (!tp->write_seq)
		tp->write_seq = secure_tcpv6_sequence_number(np->saddr.s6_addr32,
							     np->daddr.s6_addr32,
							     inet->sport,
							     inet->dport);

	err = tcp_connect(sk);
	if (err)
		goto late_failure;

	return 0;

late_failure:
	tcp_set_state(sk, TCP_CLOSE);
	__sk_dst_reset(sk);
failure:
	inet->dport = 0;
	sk->sk_route_caps = 0;
	return err;
}

static void tcp_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;
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	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
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	struct ipv6_pinfo *np;
	struct sock *sk;
	int err;
	struct tcp_sock *tp; 
	__u32 seq;

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	sk = inet6_lookup(&tcp_hashinfo, &hdr->daddr, th->dest, &hdr->saddr,
			  th->source, skb->dev->ifindex);
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	if (sk == NULL) {
		ICMP6_INC_STATS_BH(__in6_dev_get(skb->dev), ICMP6_MIB_INERRORS);
		return;
	}

	if (sk->sk_state == TCP_TIME_WAIT) {
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		inet_twsk_put((struct inet_timewait_sock *)sk);
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		return;
	}

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

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

	tp = tcp_sk(sk);
	seq = ntohl(th->seq); 
	if (sk->sk_state != TCP_LISTEN &&
	    !between(seq, tp->snd_una, tp->snd_nxt)) {
		NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
		goto out;
	}

	np = inet6_sk(sk);

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

		if (sock_owned_by_user(sk))
			goto out;
		if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
			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_TCP;
			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);

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		if (inet_csk(sk)->icsk_pmtu_cookie > dst_mtu(dst)) {
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			tcp_sync_mss(sk, dst_mtu(dst));
			tcp_simple_retransmit(sk);
		} /* else let the usual retransmit timer handle it */
		dst_release(dst);
		goto out;
	}

	icmpv6_err_convert(type, code, &err);

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	/* Might be for an request_sock */
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	switch (sk->sk_state) {
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		struct request_sock *req, **prev;
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	case TCP_LISTEN:
		if (sock_owned_by_user(sk))
			goto out;

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		req = inet6_csk_search_req(sk, &prev, th->dest, &hdr->daddr,
					   &hdr->saddr, inet6_iif(skb));
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		if (!req)
			goto out;

		/* ICMPs are not backlogged, hence we cannot get
		 * an established socket here.
		 */
		BUG_TRAP(req->sk == NULL);

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		if (seq != tcp_rsk(req)->snt_isn) {
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			NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
			goto out;
		}

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		inet_csk_reqsk_queue_drop(sk, req, prev);
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		goto out;

	case TCP_SYN_SENT:
	case TCP_SYN_RECV:  /* Cannot happen.
			       It can, it SYNs are crossed. --ANK */ 
		if (!sock_owned_by_user(sk)) {
			sk->sk_err = err;
			sk->sk_error_report(sk);		/* Wake people up to see the error (see connect in sock.c) */

			tcp_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);
}


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static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
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			      struct dst_entry *dst)
{
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	struct inet6_request_sock *treq = inet6_rsk(req);
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	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_TCP;
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	ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
	ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
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	fl.fl6_flowlabel = 0;
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	fl.oif = treq->iif;
	fl.fl_ip_dport = inet_rsk(req)->rmt_port;
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	fl.fl_ip_sport = inet_sk(sk)->sport;

	if (dst == NULL) {
		opt = np->opt;
		if (opt == NULL &&
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		    np->rxopt.bits.osrcrt == 2 &&
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		    treq->pktopts) {
			struct sk_buff *pktopts = treq->pktopts;
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			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 = tcp_make_synack(sk, dst, req);
	if (skb) {
		struct tcphdr *th = skb->h.th;

		th->check = tcp_v6_check(th, skb->len,
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					 &treq->loc_addr, &treq->rmt_addr,
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					 csum_partial((char *)th, skb->len, skb->csum));

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		ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
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		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);
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	dst_release(dst);
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	return err;
}

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static void tcp_v6_reqsk_destructor(struct request_sock *req)
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{
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	if (inet6_rsk(req)->pktopts)
		kfree_skb(inet6_rsk(req)->pktopts);
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}

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static struct request_sock_ops tcp6_request_sock_ops = {
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	.family		=	AF_INET6,
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	.obj_size	=	sizeof(struct tcp6_request_sock),
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	.rtx_syn_ack	=	tcp_v6_send_synack,
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	.send_ack	=	tcp_v6_reqsk_send_ack,
	.destructor	=	tcp_v6_reqsk_destructor,
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	.send_reset	=	tcp_v6_send_reset
};

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static struct timewait_sock_ops tcp6_timewait_sock_ops = {
	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
	.twsk_unique	= tcp_twsk_unique,
};

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static void tcp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
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{
	struct ipv6_pinfo *np = inet6_sk(sk);
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	struct tcphdr *th = skb->h.th;
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	if (skb->ip_summed == CHECKSUM_HW) {
		th->check = ~csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP,  0);
		skb->csum = offsetof(struct tcphdr, check);
	} else {
		th->check = csum_ipv6_magic(&np->saddr, &np->daddr, len, IPPROTO_TCP, 
					    csum_partial((char *)th, th->doff<<2, 
							 skb->csum));
	}
}

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static int tcp_v6_gso_send_check(struct sk_buff *skb)
{
	struct ipv6hdr *ipv6h;
	struct tcphdr *th;

	if (!pskb_may_pull(skb, sizeof(*th)))
		return -EINVAL;

	ipv6h = skb->nh.ipv6h;
	th = skb->h.th;

	th->check = 0;
	th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
				     IPPROTO_TCP, 0);
	skb->csum = offsetof(struct tcphdr, check);
	skb->ip_summed = CHECKSUM_HW;
	return 0;
}
L
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572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624

static void tcp_v6_send_reset(struct sk_buff *skb)
{
	struct tcphdr *th = skb->h.th, *t1; 
	struct sk_buff *buff;
	struct flowi fl;

	if (th->rst)
		return;

	if (!ipv6_unicast_destination(skb))
		return; 

	/*
	 * We need to grab some memory, and put together an RST,
	 * and then put it into the queue to be sent.
	 */

	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + sizeof(struct tcphdr),
			 GFP_ATOMIC);
	if (buff == NULL) 
	  	return;

	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + sizeof(struct tcphdr));

	t1 = (struct tcphdr *) skb_push(buff,sizeof(struct tcphdr));

	/* Swap the send and the receive. */
	memset(t1, 0, sizeof(*t1));
	t1->dest = th->source;
	t1->source = th->dest;
	t1->doff = sizeof(*t1)/4;
	t1->rst = 1;
  
	if(th->ack) {
	  	t1->seq = th->ack_seq;
	} else {
		t1->ack = 1;
		t1->ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin
				    + skb->len - (th->doff<<2));
	}

	buff->csum = csum_partial((char *)t1, sizeof(*t1), 0);

	memset(&fl, 0, sizeof(fl));
	ipv6_addr_copy(&fl.fl6_dst, &skb->nh.ipv6h->saddr);
	ipv6_addr_copy(&fl.fl6_src, &skb->nh.ipv6h->daddr);

	t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
				    sizeof(*t1), IPPROTO_TCP,
				    buff->csum);

	fl.proto = IPPROTO_TCP;
625
	fl.oif = inet6_iif(skb);
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	fl.fl_ip_dport = t1->dest;
	fl.fl_ip_sport = t1->source;

	/* sk = NULL, but it is safe for now. RST socket required. */
	if (!ip6_dst_lookup(NULL, &buff->dst, &fl)) {

A
Arnaldo Carvalho de Melo 已提交
632
		if (xfrm_lookup(&buff->dst, &fl, NULL, 0) >= 0) {
633
			ip6_xmit(tcp6_socket->sk, buff, &fl, NULL, 0);
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			TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
			TCP_INC_STATS_BH(TCP_MIB_OUTRSTS);
L
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636
			return;
A
Arnaldo Carvalho de Melo 已提交
637
		}
L
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	}

	kfree_skb(buff);
}

static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts)
{
	struct tcphdr *th = skb->h.th, *t1;
	struct sk_buff *buff;
	struct flowi fl;
	int tot_len = sizeof(struct tcphdr);

	if (ts)
		tot_len += 3*4;

	buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
			 GFP_ATOMIC);
	if (buff == NULL)
		return;

	skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);

	t1 = (struct tcphdr *) skb_push(buff,tot_len);

	/* Swap the send and the receive. */
	memset(t1, 0, sizeof(*t1));
	t1->dest = th->source;
	t1->source = th->dest;
	t1->doff = tot_len/4;
	t1->seq = htonl(seq);
	t1->ack_seq = htonl(ack);
	t1->ack = 1;
	t1->window = htons(win);
	
	if (ts) {
		u32 *ptr = (u32*)(t1 + 1);
		*ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
			       (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
		*ptr++ = htonl(tcp_time_stamp);
		*ptr = htonl(ts);
	}

	buff->csum = csum_partial((char *)t1, tot_len, 0);

	memset(&fl, 0, sizeof(fl));
	ipv6_addr_copy(&fl.fl6_dst, &skb->nh.ipv6h->saddr);
	ipv6_addr_copy(&fl.fl6_src, &skb->nh.ipv6h->daddr);

	t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst,
				    tot_len, IPPROTO_TCP,
				    buff->csum);

	fl.proto = IPPROTO_TCP;
691
	fl.oif = inet6_iif(skb);
L
Linus Torvalds 已提交
692 693 694 695
	fl.fl_ip_dport = t1->dest;
	fl.fl_ip_sport = t1->source;

	if (!ip6_dst_lookup(NULL, &buff->dst, &fl)) {
A
Arnaldo Carvalho de Melo 已提交
696
		if (xfrm_lookup(&buff->dst, &fl, NULL, 0) >= 0) {
697
			ip6_xmit(tcp6_socket->sk, buff, &fl, NULL, 0);
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Arnaldo Carvalho de Melo 已提交
698
			TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
L
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699
			return;
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700
		}
L
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701 702 703 704 705 706 707
	}

	kfree_skb(buff);
}

static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
708 709
	struct inet_timewait_sock *tw = inet_twsk(sk);
	const struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
710

711 712 713
	tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
			tcptw->tw_ts_recent);
L
Linus Torvalds 已提交
714

715
	inet_twsk_put(tw);
L
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716 717
}

718
static void tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
L
Linus Torvalds 已提交
719
{
720
	tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent);
L
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721 722 723 724 725
}


static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
{
726
	struct request_sock *req, **prev;
727
	const struct tcphdr *th = skb->h.th;
L
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728 729 730
	struct sock *nsk;

	/* Find possible connection requests. */
731 732 733
	req = inet6_csk_search_req(sk, &prev, th->source,
				   &skb->nh.ipv6h->saddr,
				   &skb->nh.ipv6h->daddr, inet6_iif(skb));
L
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734 735 736
	if (req)
		return tcp_check_req(sk, skb, req, prev);

737 738 739
	nsk = __inet6_lookup_established(&tcp_hashinfo, &skb->nh.ipv6h->saddr,
					 th->source, &skb->nh.ipv6h->daddr,
					 ntohs(th->dest), inet6_iif(skb));
L
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740 741 742 743 744 745

	if (nsk) {
		if (nsk->sk_state != TCP_TIME_WAIT) {
			bh_lock_sock(nsk);
			return nsk;
		}
746
		inet_twsk_put((struct inet_timewait_sock *)nsk);
L
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747 748 749 750 751 752 753 754 755 756 757 758 759 760 761
		return NULL;
	}

#if 0 /*def CONFIG_SYN_COOKIES*/
	if (!th->rst && !th->syn && th->ack)
		sk = cookie_v6_check(sk, skb, &(IPCB(skb)->opt));
#endif
	return sk;
}

/* FIXME: this is substantially similar to the ipv4 code.
 * Can some kind of merge be done? -- erics
 */
static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
{
762
	struct inet6_request_sock *treq;
L
Linus Torvalds 已提交
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	struct ipv6_pinfo *np = inet6_sk(sk);
	struct tcp_options_received tmp_opt;
	struct tcp_sock *tp = tcp_sk(sk);
766
	struct request_sock *req = NULL;
L
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	__u32 isn = TCP_SKB_CB(skb)->when;

	if (skb->protocol == htons(ETH_P_IP))
		return tcp_v4_conn_request(sk, skb);

	if (!ipv6_unicast_destination(skb))
		goto drop; 

	/*
	 *	There are no SYN attacks on IPv6, yet...	
	 */
778
	if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
L
Linus Torvalds 已提交
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		if (net_ratelimit())
			printk(KERN_INFO "TCPv6: dropping request, synflood is possible\n");
		goto drop;		
	}

784
	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
L
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785 786
		goto drop;

787
	req = inet6_reqsk_alloc(&tcp6_request_sock_ops);
L
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788 789 790 791 792 793 794 795 796 797 798 799
	if (req == NULL)
		goto drop;

	tcp_clear_options(&tmp_opt);
	tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
	tmp_opt.user_mss = tp->rx_opt.user_mss;

	tcp_parse_options(skb, &tmp_opt, 0);

	tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
	tcp_openreq_init(req, &tmp_opt, skb);

800
	treq = inet6_rsk(req);
801 802
	ipv6_addr_copy(&treq->rmt_addr, &skb->nh.ipv6h->saddr);
	ipv6_addr_copy(&treq->loc_addr, &skb->nh.ipv6h->daddr);
L
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803
	TCP_ECN_create_request(req, skb->h.th);
804
	treq->pktopts = NULL;
L
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805
	if (ipv6_opt_accepted(sk, skb) ||
806 807
	    np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
	    np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
L
Linus Torvalds 已提交
808
		atomic_inc(&skb->users);
809
		treq->pktopts = skb;
L
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810
	}
811
	treq->iif = sk->sk_bound_dev_if;
L
Linus Torvalds 已提交
812 813 814

	/* So that link locals have meaning */
	if (!sk->sk_bound_dev_if &&
815
	    ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
816
		treq->iif = inet6_iif(skb);
L
Linus Torvalds 已提交
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	if (isn == 0) 
		isn = tcp_v6_init_sequence(sk,skb);

821
	tcp_rsk(req)->snt_isn = isn;
L
Linus Torvalds 已提交
822 823 824 825

	if (tcp_v6_send_synack(sk, req, NULL))
		goto drop;

826
	inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
L
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827 828 829 830
	return 0;

drop:
	if (req)
831
		reqsk_free(req);
L
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832 833 834 835 836

	return 0; /* don't send reset */
}

static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
837
					  struct request_sock *req,
L
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838 839
					  struct dst_entry *dst)
{
840
	struct inet6_request_sock *treq = inet6_rsk(req);
L
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841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874
	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
	struct tcp6_sock *newtcp6sk;
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
	struct ipv6_txoptions *opt;

	if (skb->protocol == htons(ETH_P_IP)) {
		/*
		 *	v6 mapped
		 */

		newsk = tcp_v4_syn_recv_sock(sk, skb, req, dst);

		if (newsk == NULL) 
			return NULL;

		newtcp6sk = (struct tcp6_sock *)newsk;
		inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;

		newinet = inet_sk(newsk);
		newnp = inet6_sk(newsk);
		newtp = tcp_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);

875
		inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
L
Linus Torvalds 已提交
876 877 878
		newsk->sk_backlog_rcv = tcp_v4_do_rcv;
		newnp->pktoptions  = NULL;
		newnp->opt	   = NULL;
879
		newnp->mcast_oif   = inet6_iif(skb);
L
Linus Torvalds 已提交
880 881
		newnp->mcast_hops  = skb->nh.ipv6h->hop_limit;

882 883 884 885
		/*
		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
		 * here, tcp_create_openreq_child now does this for us, see the comment in
		 * that function for the gory details. -acme
L
Linus Torvalds 已提交
886 887 888
		 */

		/* It is tricky place. Until this moment IPv4 tcp
889
		   worked with IPv6 icsk.icsk_af_ops.
L
Linus Torvalds 已提交
890 891
		   Sync it now.
		 */
892
		tcp_sync_mss(newsk, inet_csk(newsk)->icsk_pmtu_cookie);
L
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893 894 895 896 897 898 899 900 901

		return newsk;
	}

	opt = np->opt;

	if (sk_acceptq_is_full(sk))
		goto out_overflow;

902
	if (np->rxopt.bits.osrcrt == 2 &&
903 904
	    opt == NULL && treq->pktopts) {
		struct inet6_skb_parm *rxopt = IP6CB(treq->pktopts);
L
Linus Torvalds 已提交
905
		if (rxopt->srcrt)
906
			opt = ipv6_invert_rthdr(sk, (struct ipv6_rt_hdr *)(treq->pktopts->nh.raw + rxopt->srcrt));
L
Linus Torvalds 已提交
907 908 909 910 911 912 913 914
	}

	if (dst == NULL) {
		struct in6_addr *final_p = NULL, final;
		struct flowi fl;

		memset(&fl, 0, sizeof(fl));
		fl.proto = IPPROTO_TCP;
915
		ipv6_addr_copy(&fl.fl6_dst, &treq->rmt_addr);
L
Linus Torvalds 已提交
916 917 918 919 920 921
		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;
		}
922
		ipv6_addr_copy(&fl.fl6_src, &treq->loc_addr);
L
Linus Torvalds 已提交
923
		fl.oif = sk->sk_bound_dev_if;
924
		fl.fl_ip_dport = inet_rsk(req)->rmt_port;
L
Linus Torvalds 已提交
925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940
		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 = tcp_create_openreq_child(sk, req, skb);
	if (newsk == NULL)
		goto out;

941 942 943 944 945
	/*
	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
	 * count here, tcp_create_openreq_child now does this for us, see the
	 * comment in that function for the gory details. -acme
	 */
L
Linus Torvalds 已提交
946

H
Herbert Xu 已提交
947
	sk->sk_gso_type = SKB_GSO_TCPV6;
948
	__ip6_dst_store(newsk, dst, NULL);
L
Linus Torvalds 已提交
949 950 951 952 953 954 955 956 957 958

	newtcp6sk = (struct tcp6_sock *)newsk;
	inet_sk(newsk)->pinet6 = &newtcp6sk->inet6;

	newtp = tcp_sk(newsk);
	newinet = inet_sk(newsk);
	newnp = inet6_sk(newsk);

	memcpy(newnp, np, sizeof(struct ipv6_pinfo));

959 960 961 962
	ipv6_addr_copy(&newnp->daddr, &treq->rmt_addr);
	ipv6_addr_copy(&newnp->saddr, &treq->loc_addr);
	ipv6_addr_copy(&newnp->rcv_saddr, &treq->loc_addr);
	newsk->sk_bound_dev_if = treq->iif;
L
Linus Torvalds 已提交
963 964 965 966 967 968 969 970 971 972 973 974

	/* 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;
975 976 977 978
	if (treq->pktopts != NULL) {
		newnp->pktoptions = skb_clone(treq->pktopts, GFP_ATOMIC);
		kfree_skb(treq->pktopts);
		treq->pktopts = NULL;
L
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979 980 981 982
		if (newnp->pktoptions)
			skb_set_owner_r(newnp->pktoptions, newsk);
	}
	newnp->opt	  = NULL;
983
	newnp->mcast_oif  = inet6_iif(skb);
L
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984 985 986 987 988 989 990 991 992 993 994 995 996 997
	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);
	}

998
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
L
Linus Torvalds 已提交
999
	if (newnp->opt)
1000 1001
		inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
						     newnp->opt->opt_flen);
L
Linus Torvalds 已提交
1002

J
John Heffner 已提交
1003
	tcp_mtup_init(newsk);
L
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1004 1005 1006 1007 1008 1009
	tcp_sync_mss(newsk, dst_mtu(dst));
	newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
	tcp_initialize_rcv_mss(newsk);

	newinet->daddr = newinet->saddr = newinet->rcv_saddr = LOOPBACK4_IPV6;

1010
	__inet6_hash(&tcp_hashinfo, newsk);
1011
	inet_inherit_port(&tcp_hashinfo, sk, newsk);
L
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1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028

	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;
}

static int tcp_v6_checksum_init(struct sk_buff *skb)
{
	if (skb->ip_summed == CHECKSUM_HW) {
		if (!tcp_v6_check(skb->h.th,skb->len,&skb->nh.ipv6h->saddr,
1029 1030
				  &skb->nh.ipv6h->daddr,skb->csum)) {
			skb->ip_summed = CHECKSUM_UNNECESSARY;
L
Linus Torvalds 已提交
1031
			return 0;
1032
		}
L
Linus Torvalds 已提交
1033
	}
1034 1035 1036 1037

	skb->csum = ~tcp_v6_check(skb->h.th,skb->len,&skb->nh.ipv6h->saddr,
				  &skb->nh.ipv6h->daddr, 0);

L
Linus Torvalds 已提交
1038
	if (skb->len <= 76) {
1039
		return __skb_checksum_complete(skb);
L
Linus Torvalds 已提交
1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
	}
	return 0;
}

/* 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 tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
{
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct tcp_sock *tp;
	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, tcp_rcv_established and rcv_established
	   handle them correctly, but it is not case with
	   tcp_v6_hnd_req and tcp_v6_send_reset().   --ANK
	 */

	if (skb->protocol == htons(ETH_P_IP))
		return tcp_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 == TCP_ESTABLISHED) { /* Fast path */
		TCP_CHECK_TIMER(sk);
		if (tcp_rcv_established(sk, skb, skb->h.th, skb->len))
			goto reset;
		TCP_CHECK_TIMER(sk);
		if (opt_skb)
			goto ipv6_pktoptions;
		return 0;
	}

	if (skb->len < (skb->h.th->doff<<2) || tcp_checksum_complete(skb))
		goto csum_err;

	if (sk->sk_state == TCP_LISTEN) { 
		struct sock *nsk = tcp_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 (tcp_child_process(sk, nsk, skb))
				goto reset;
			if (opt_skb)
				__kfree_skb(opt_skb);
			return 0;
		}
	}

	TCP_CHECK_TIMER(sk);
	if (tcp_rcv_state_process(sk, skb, skb->h.th, skb->len))
		goto reset;
	TCP_CHECK_TIMER(sk);
	if (opt_skb)
		goto ipv6_pktoptions;
	return 0;

reset:
	tcp_v6_send_reset(skb);
discard:
	if (opt_skb)
		__kfree_skb(opt_skb);
	kfree_skb(skb);
	return 0;
csum_err:
	TCP_INC_STATS_BH(TCP_MIB_INERRS);
	goto discard;


ipv6_pktoptions:
	/* Do you ask, what is it?

	   1. skb was enqueued by tcp.
	   2. skb is added to tail of read queue, rather than out of order.
	   3. socket is not in passive state.
	   4. Finally, it really contains options, which user wants to receive.
	 */
	tp = tcp_sk(sk);
	if (TCP_SKB_CB(opt_skb)->end_seq == tp->rcv_nxt &&
	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
1156
		if (np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo)
1157
			np->mcast_oif = inet6_iif(opt_skb);
1158
		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
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			np->mcast_hops = opt_skb->nh.ipv6h->hop_limit;
		if (ipv6_opt_accepted(sk, opt_skb)) {
			skb_set_owner_r(opt_skb, sk);
			opt_skb = xchg(&np->pktoptions, opt_skb);
		} else {
			__kfree_skb(opt_skb);
			opt_skb = xchg(&np->pktoptions, NULL);
		}
	}

	if (opt_skb)
		kfree_skb(opt_skb);
	return 0;
}

1174
static int tcp_v6_rcv(struct sk_buff **pskb)
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1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199
{
	struct sk_buff *skb = *pskb;
	struct tcphdr *th;	
	struct sock *sk;
	int ret;

	if (skb->pkt_type != PACKET_HOST)
		goto discard_it;

	/*
	 *	Count it even if it's bad.
	 */
	TCP_INC_STATS_BH(TCP_MIB_INSEGS);

	if (!pskb_may_pull(skb, sizeof(struct tcphdr)))
		goto discard_it;

	th = skb->h.th;

	if (th->doff < sizeof(struct tcphdr)/4)
		goto bad_packet;
	if (!pskb_may_pull(skb, th->doff*4))
		goto discard_it;

	if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
1200
	     tcp_v6_checksum_init(skb)))
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		goto bad_packet;

	th = skb->h.th;
	TCP_SKB_CB(skb)->seq = ntohl(th->seq);
	TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
				    skb->len - th->doff*4);
	TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
	TCP_SKB_CB(skb)->when = 0;
	TCP_SKB_CB(skb)->flags = ipv6_get_dsfield(skb->nh.ipv6h);
	TCP_SKB_CB(skb)->sacked = 0;

1212 1213 1214
	sk = __inet6_lookup(&tcp_hashinfo, &skb->nh.ipv6h->saddr, th->source,
			    &skb->nh.ipv6h->daddr, ntohs(th->dest),
			    inet6_iif(skb));
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	if (!sk)
		goto no_tcp_socket;

process:
	if (sk->sk_state == TCP_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);
	ret = 0;
	if (!sock_owned_by_user(sk)) {
C
Chris Leech 已提交
1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
#ifdef CONFIG_NET_DMA
                struct tcp_sock *tp = tcp_sk(sk);
                if (tp->ucopy.dma_chan)
                        ret = tcp_v6_do_rcv(sk, skb);
                else
#endif
		{
			if (!tcp_prequeue(sk, skb))
				ret = tcp_v6_do_rcv(sk, skb);
		}
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	} else
		sk_add_backlog(sk, skb);
	bh_unlock_sock(sk);

	sock_put(sk);
	return ret ? -1 : 0;

no_tcp_socket:
	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto discard_it;

	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
bad_packet:
		TCP_INC_STATS_BH(TCP_MIB_INERRS);
	} else {
		tcp_v6_send_reset(skb);
	}

discard_it:

	/*
	 *	Discard frame
	 */

	kfree_skb(skb);
	return 0;

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1277
		inet_twsk_put((struct inet_timewait_sock *)sk);
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		goto discard_it;
	}

	if (skb->len < (th->doff<<2) || tcp_checksum_complete(skb)) {
		TCP_INC_STATS_BH(TCP_MIB_INERRS);
1283
		inet_twsk_put((struct inet_timewait_sock *)sk);
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		goto discard_it;
	}

1287 1288
	switch (tcp_timewait_state_process((struct inet_timewait_sock *)sk,
					   skb, th)) {
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	case TCP_TW_SYN:
	{
		struct sock *sk2;

1293 1294 1295
		sk2 = inet6_lookup_listener(&tcp_hashinfo,
					    &skb->nh.ipv6h->daddr,
					    ntohs(th->dest), inet6_iif(skb));
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		if (sk2 != NULL) {
1297 1298 1299
			struct inet_timewait_sock *tw = inet_twsk(sk);
			inet_twsk_deschedule(tw, &tcp_death_row);
			inet_twsk_put(tw);
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			sk = sk2;
			goto process;
		}
		/* Fall through to ACK */
	}
	case TCP_TW_ACK:
		tcp_v6_timewait_ack(sk, skb);
		break;
	case TCP_TW_RST:
		goto no_tcp_socket;
	case TCP_TW_SUCCESS:;
	}
	goto discard_it;
}

static int tcp_v6_remember_stamp(struct sock *sk)
{
	/* Alas, not yet... */
	return 0;
}

1321
static struct inet_connection_sock_af_ops ipv6_specific = {
1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332
	.queue_xmit	   = inet6_csk_xmit,
	.send_check	   = tcp_v6_send_check,
	.rebuild_header	   = inet6_sk_rebuild_header,
	.conn_request	   = tcp_v6_conn_request,
	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
	.remember_stamp	   = tcp_v6_remember_stamp,
	.net_header_len	   = sizeof(struct ipv6hdr),
	.setsockopt	   = ipv6_setsockopt,
	.getsockopt	   = ipv6_getsockopt,
	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1333
#ifdef CONFIG_COMPAT
1334 1335
	.compat_setsockopt = compat_ipv6_setsockopt,
	.compat_getsockopt = compat_ipv6_getsockopt,
1336
#endif
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};

/*
 *	TCP over IPv4 via INET6 API
 */

1343
static struct inet_connection_sock_af_ops ipv6_mapped = {
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
	.conn_request	   = tcp_v6_conn_request,
	.syn_recv_sock	   = tcp_v6_syn_recv_sock,
	.remember_stamp	   = tcp_v4_remember_stamp,
	.net_header_len	   = sizeof(struct iphdr),
	.setsockopt	   = ipv6_setsockopt,
	.getsockopt	   = ipv6_getsockopt,
	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in6),
1355
#ifdef CONFIG_COMPAT
1356 1357
	.compat_setsockopt = compat_ipv6_setsockopt,
	.compat_getsockopt = compat_ipv6_getsockopt,
1358
#endif
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};

/* NOTE: A lot of things set to zero explicitly by call to
 *       sk_alloc() so need not be done here.
 */
static int tcp_v6_init_sock(struct sock *sk)
{
1366
	struct inet_connection_sock *icsk = inet_csk(sk);
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	struct tcp_sock *tp = tcp_sk(sk);

	skb_queue_head_init(&tp->out_of_order_queue);
	tcp_init_xmit_timers(sk);
	tcp_prequeue_init(tp);

1373
	icsk->icsk_rto = TCP_TIMEOUT_INIT;
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	tp->mdev = TCP_TIMEOUT_INIT;

	/* So many TCP implementations out there (incorrectly) count the
	 * initial SYN frame in their delayed-ACK and congestion control
	 * algorithms that we must have the following bandaid to talk
	 * efficiently to them.  -DaveM
	 */
	tp->snd_cwnd = 2;

	/* See draft-stevens-tcpca-spec-01 for discussion of the
	 * initialization of these values.
	 */
	tp->snd_ssthresh = 0x7fffffff;
	tp->snd_cwnd_clamp = ~0;
1388
	tp->mss_cache = 536;
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1389 1390 1391 1392 1393

	tp->reordering = sysctl_tcp_reordering;

	sk->sk_state = TCP_CLOSE;

1394
	icsk->icsk_af_ops = &ipv6_specific;
1395
	icsk->icsk_ca_ops = &tcp_init_congestion_ops;
1396
	icsk->icsk_sync_mss = tcp_sync_mss;
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	sk->sk_write_space = sk_stream_write_space;
	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);

	sk->sk_sndbuf = sysctl_tcp_wmem[1];
	sk->sk_rcvbuf = sysctl_tcp_rmem[1];

	atomic_inc(&tcp_sockets_allocated);

	return 0;
}

static int tcp_v6_destroy_sock(struct sock *sk)
{
	tcp_v4_destroy_sock(sk);
	return inet6_destroy_sock(sk);
}

/* Proc filesystem TCPv6 sock list dumping. */
static void get_openreq6(struct seq_file *seq, 
1416
			 struct sock *sk, struct request_sock *req, int i, int uid)
L
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1417 1418
{
	int ttd = req->expires - jiffies;
1419 1420
	struct in6_addr *src = &inet6_rsk(req)->loc_addr;
	struct in6_addr *dest = &inet6_rsk(req)->rmt_addr;
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1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433

	if (ttd < 0)
		ttd = 0;

	seq_printf(seq,
		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
		   i,
		   src->s6_addr32[0], src->s6_addr32[1],
		   src->s6_addr32[2], src->s6_addr32[3],
		   ntohs(inet_sk(sk)->sport),
		   dest->s6_addr32[0], dest->s6_addr32[1],
		   dest->s6_addr32[2], dest->s6_addr32[3],
1434
		   ntohs(inet_rsk(req)->rmt_port),
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1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453
		   TCP_SYN_RECV,
		   0,0, /* could print option size, but that is af dependent. */
		   1,   /* timers active (only the expire timer) */  
		   jiffies_to_clock_t(ttd), 
		   req->retrans,
		   uid,
		   0,  /* non standard timer */  
		   0, /* open_requests have no inode */
		   0, req);
}

static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
{
	struct in6_addr *dest, *src;
	__u16 destp, srcp;
	int timer_active;
	unsigned long timer_expires;
	struct inet_sock *inet = inet_sk(sp);
	struct tcp_sock *tp = tcp_sk(sp);
1454
	const struct inet_connection_sock *icsk = inet_csk(sp);
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1455 1456 1457 1458 1459 1460
	struct ipv6_pinfo *np = inet6_sk(sp);

	dest  = &np->daddr;
	src   = &np->rcv_saddr;
	destp = ntohs(inet->dport);
	srcp  = ntohs(inet->sport);
1461 1462

	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
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1463
		timer_active	= 1;
1464 1465
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
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1466
		timer_active	= 4;
1467
		timer_expires	= icsk->icsk_timeout;
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1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484
	} else if (timer_pending(&sp->sk_timer)) {
		timer_active	= 2;
		timer_expires	= sp->sk_timer.expires;
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

	seq_printf(seq,
		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %u %u %u %u %d\n",
		   i,
		   src->s6_addr32[0], src->s6_addr32[1],
		   src->s6_addr32[2], src->s6_addr32[3], srcp,
		   dest->s6_addr32[0], dest->s6_addr32[1],
		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
		   sp->sk_state, 
1485 1486
		   tp->write_seq-tp->snd_una,
		   (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq),
L
Linus Torvalds 已提交
1487 1488
		   timer_active,
		   jiffies_to_clock_t(timer_expires - jiffies),
1489
		   icsk->icsk_retransmits,
L
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1490
		   sock_i_uid(sp),
1491
		   icsk->icsk_probes_out,
L
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1492 1493
		   sock_i_ino(sp),
		   atomic_read(&sp->sk_refcnt), sp,
1494 1495 1496
		   icsk->icsk_rto,
		   icsk->icsk_ack.ato,
		   (icsk->icsk_ack.quick << 1 ) | icsk->icsk_ack.pingpong,
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		   tp->snd_cwnd, tp->snd_ssthresh>=0xFFFF?-1:tp->snd_ssthresh
		   );
}

static void get_timewait6_sock(struct seq_file *seq, 
1502
			       struct inet_timewait_sock *tw, int i)
L
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1503 1504 1505
{
	struct in6_addr *dest, *src;
	__u16 destp, srcp;
1506
	struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
L
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1507 1508 1509 1510 1511
	int ttd = tw->tw_ttd - jiffies;

	if (ttd < 0)
		ttd = 0;

1512 1513
	dest = &tw6->tw_v6_daddr;
	src  = &tw6->tw_v6_rcv_saddr;
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1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587
	destp = ntohs(tw->tw_dport);
	srcp  = ntohs(tw->tw_sport);

	seq_printf(seq,
		   "%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
		   "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p\n",
		   i,
		   src->s6_addr32[0], src->s6_addr32[1],
		   src->s6_addr32[2], src->s6_addr32[3], srcp,
		   dest->s6_addr32[0], dest->s6_addr32[1],
		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
		   tw->tw_substate, 0, 0,
		   3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
		   atomic_read(&tw->tw_refcnt), tw);
}

#ifdef CONFIG_PROC_FS
static int tcp6_seq_show(struct seq_file *seq, void *v)
{
	struct tcp_iter_state *st;

	if (v == SEQ_START_TOKEN) {
		seq_puts(seq,
			 "  sl  "
			 "local_address                         "
			 "remote_address                        "
			 "st tx_queue rx_queue tr tm->when retrnsmt"
			 "   uid  timeout inode\n");
		goto out;
	}
	st = seq->private;

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
	case TCP_SEQ_STATE_ESTABLISHED:
		get_tcp6_sock(seq, v, st->num);
		break;
	case TCP_SEQ_STATE_OPENREQ:
		get_openreq6(seq, st->syn_wait_sk, v, st->num, st->uid);
		break;
	case TCP_SEQ_STATE_TIME_WAIT:
		get_timewait6_sock(seq, v, st->num);
		break;
	}
out:
	return 0;
}

static struct file_operations tcp6_seq_fops;
static struct tcp_seq_afinfo tcp6_seq_afinfo = {
	.owner		= THIS_MODULE,
	.name		= "tcp6",
	.family		= AF_INET6,
	.seq_show	= tcp6_seq_show,
	.seq_fops	= &tcp6_seq_fops,
};

int __init tcp6_proc_init(void)
{
	return tcp_proc_register(&tcp6_seq_afinfo);
}

void tcp6_proc_exit(void)
{
	tcp_proc_unregister(&tcp6_seq_afinfo);
}
#endif

struct proto tcpv6_prot = {
	.name			= "TCPv6",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v6_connect,
	.disconnect		= tcp_disconnect,
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	.accept			= inet_csk_accept,
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	.ioctl			= tcp_ioctl,
	.init			= tcp_v6_init_sock,
	.destroy		= tcp_v6_destroy_sock,
	.shutdown		= tcp_shutdown,
	.setsockopt		= tcp_setsockopt,
	.getsockopt		= tcp_getsockopt,
	.sendmsg		= tcp_sendmsg,
	.recvmsg		= tcp_recvmsg,
	.backlog_rcv		= tcp_v6_do_rcv,
	.hash			= tcp_v6_hash,
	.unhash			= tcp_unhash,
	.get_port		= tcp_v6_get_port,
	.enter_memory_pressure	= tcp_enter_memory_pressure,
	.sockets_allocated	= &tcp_sockets_allocated,
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
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	.orphan_count		= &tcp_orphan_count,
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	.sysctl_mem		= sysctl_tcp_mem,
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp6_sock),
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	.twsk_prot		= &tcp6_timewait_sock_ops,
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	.rsk_prot		= &tcp6_request_sock_ops,
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#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
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};

static struct inet6_protocol tcpv6_protocol = {
	.handler	=	tcp_v6_rcv,
	.err_handler	=	tcp_v6_err,
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	.gso_send_check	=	tcp_v6_gso_send_check,
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	.gso_segment	=	tcp_tso_segment,
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	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};

static struct inet_protosw tcpv6_protosw = {
	.type		=	SOCK_STREAM,
	.protocol	=	IPPROTO_TCP,
	.prot		=	&tcpv6_prot,
	.ops		=	&inet6_stream_ops,
	.capability	=	-1,
	.no_check	=	0,
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	.flags		=	INET_PROTOSW_PERMANENT |
				INET_PROTOSW_ICSK,
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};

void __init tcpv6_init(void)
{
	/* register inet6 protocol */
	if (inet6_add_protocol(&tcpv6_protocol, IPPROTO_TCP) < 0)
		printk(KERN_ERR "tcpv6_init: Could not register protocol\n");
	inet6_register_protosw(&tcpv6_protosw);
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	if (inet_csk_ctl_sock_create(&tcp6_socket, PF_INET6, SOCK_RAW,
				     IPPROTO_TCP) < 0)
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		panic("Failed to create the TCPv6 control socket.\n");
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}