tcp_ipv4.c 65.6 KB
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/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Implementation of the Transmission Control Protocol(TCP).
 *
 *		IPv4 specific functions
 *
 *
 *		code split from:
 *		linux/ipv4/tcp.c
 *		linux/ipv4/tcp_input.c
 *		linux/ipv4/tcp_output.c
 *
 *		See tcp.c for author information
 *
 *	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.
 */

/*
 * Changes:
 *		David S. Miller	:	New socket lookup architecture.
 *					This code is dedicated to John Dyson.
 *		David S. Miller :	Change semantics of established hash,
 *					half is devoted to TIME_WAIT sockets
 *					and the rest go in the other half.
 *		Andi Kleen :		Add support for syncookies and fixed
 *					some bugs: ip options weren't passed to
 *					the TCP layer, missed a check for an
 *					ACK bit.
 *		Andi Kleen :		Implemented fast path mtu discovery.
 *	     				Fixed many serious bugs in the
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 *					request_sock handling and moved
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 *					most of it into the af independent code.
 *					Added tail drop and some other bugfixes.
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 *					Added new listen semantics.
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 *		Mike McLagan	:	Routing by source
 *	Juan Jose Ciarlante:		ip_dynaddr bits
 *		Andi Kleen:		various fixes.
 *	Vitaly E. Lavrov	:	Transparent proxy revived after year
 *					coma.
 *	Andi Kleen		:	Fix new listen.
 *	Andi Kleen		:	Fix accept error reporting.
 *	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.
 */


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#include <linux/bottom_half.h>
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#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/cache.h>
#include <linux/jhash.h>
#include <linux/init.h>
#include <linux/times.h>
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#include <linux/slab.h>
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#include <net/net_namespace.h>
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#include <net/icmp.h>
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#include <net/inet_hashtables.h>
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#include <net/tcp.h>
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#include <net/transp_v6.h>
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#include <net/ipv6.h>
#include <net/inet_common.h>
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#include <net/timewait_sock.h>
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#include <net/xfrm.h>
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#include <net/netdma.h>
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#include <linux/inet.h>
#include <linux/ipv6.h>
#include <linux/stddef.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

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#include <linux/crypto.h>
#include <linux/scatterlist.h>

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int sysctl_tcp_tw_reuse __read_mostly;
int sysctl_tcp_low_latency __read_mostly;
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EXPORT_SYMBOL(sysctl_tcp_low_latency);
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#ifdef CONFIG_TCP_MD5SIG
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static struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk,
						   __be32 addr);
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static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
			       __be32 daddr, __be32 saddr, struct tcphdr *th);
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#else
static inline
struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
{
	return NULL;
}
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#endif

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struct inet_hashinfo tcp_hashinfo;
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EXPORT_SYMBOL(tcp_hashinfo);
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static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
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{
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	return secure_tcp_sequence_number(ip_hdr(skb)->daddr,
					  ip_hdr(skb)->saddr,
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					  tcp_hdr(skb)->dest,
					  tcp_hdr(skb)->source);
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}

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int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
{
	const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw);
	struct tcp_sock *tp = tcp_sk(sk);

	/* With PAWS, it is safe from the viewpoint
	   of data integrity. Even without PAWS it is safe provided sequence
	   spaces do not overlap i.e. at data rates <= 80Mbit/sec.

	   Actually, the idea is close to VJ's one, only timestamp cache is
	   held not per host, but per port pair and TW bucket is used as state
	   holder.

	   If TW bucket has been already destroyed we fall back to VJ's scheme
	   and use initial timestamp retrieved from peer table.
	 */
	if (tcptw->tw_ts_recent_stamp &&
	    (twp == NULL || (sysctl_tcp_tw_reuse &&
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			     get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
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		tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
		if (tp->write_seq == 0)
			tp->write_seq = 1;
		tp->rx_opt.ts_recent	   = tcptw->tw_ts_recent;
		tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
		sock_hold(sktw);
		return 1;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(tcp_twsk_unique);

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/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
	struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
	struct rtable *rt;
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	__be32 daddr, nexthop;
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	int tmp;
	int err;

	if (addr_len < sizeof(struct sockaddr_in))
		return -EINVAL;

	if (usin->sin_family != AF_INET)
		return -EAFNOSUPPORT;

	nexthop = daddr = usin->sin_addr.s_addr;
	if (inet->opt && inet->opt->srr) {
		if (!daddr)
			return -EINVAL;
		nexthop = inet->opt->faddr;
	}

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	tmp = ip_route_connect(&rt, nexthop, inet->inet_saddr,
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			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			       IPPROTO_TCP,
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			       inet->inet_sport, usin->sin_port, sk, 1);
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	if (tmp < 0) {
		if (tmp == -ENETUNREACH)
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			IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
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		return tmp;
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	}
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	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		return -ENETUNREACH;
	}

	if (!inet->opt || !inet->opt->srr)
		daddr = rt->rt_dst;

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	if (!inet->inet_saddr)
		inet->inet_saddr = rt->rt_src;
	inet->inet_rcv_saddr = inet->inet_saddr;
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	if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
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		/* Reset inherited state */
		tp->rx_opt.ts_recent	   = 0;
		tp->rx_opt.ts_recent_stamp = 0;
		tp->write_seq		   = 0;
	}

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	if (tcp_death_row.sysctl_tw_recycle &&
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	    !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
		struct inet_peer *peer = rt_get_peer(rt);
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		/*
		 * VJ's idea. We save last timestamp seen from
		 * the destination in peer table, when entering state
		 * TIME-WAIT * and initialize rx_opt.ts_recent from it,
		 * when trying new connection.
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		 */
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		if (peer) {
			inet_peer_refcheck(peer);
			if ((u32)get_seconds() - peer->tcp_ts_stamp <= TCP_PAWS_MSL) {
				tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
				tp->rx_opt.ts_recent = peer->tcp_ts;
			}
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		}
	}

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	inet->inet_dport = usin->sin_port;
	inet->inet_daddr = daddr;
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	inet_csk(sk)->icsk_ext_hdr_len = 0;
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	if (inet->opt)
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		inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
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	tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT;
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	/* Socket identity is still unknown (sport may be zero).
	 * However we set state to SYN-SENT and not releasing socket
	 * lock select source port, enter ourselves into the hash tables and
	 * complete initialization after this.
	 */
	tcp_set_state(sk, TCP_SYN_SENT);
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	err = inet_hash_connect(&tcp_death_row, sk);
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	if (err)
		goto failure;

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	err = ip_route_newports(&rt, IPPROTO_TCP,
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				inet->inet_sport, inet->inet_dport, sk);
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	if (err)
		goto failure;

	/* OK, now commit destination to socket.  */
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	sk->sk_gso_type = SKB_GSO_TCPV4;
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	sk_setup_caps(sk, &rt->dst);
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	if (!tp->write_seq)
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		tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr,
							   inet->inet_daddr,
							   inet->inet_sport,
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							   usin->sin_port);

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	inet->inet_id = tp->write_seq ^ jiffies;
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	err = tcp_connect(sk);
	rt = NULL;
	if (err)
		goto failure;

	return 0;

failure:
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	/*
	 * This unhashes the socket and releases the local port,
	 * if necessary.
	 */
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	tcp_set_state(sk, TCP_CLOSE);
	ip_rt_put(rt);
	sk->sk_route_caps = 0;
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	inet->inet_dport = 0;
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	return err;
}
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EXPORT_SYMBOL(tcp_v4_connect);
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/*
 * This routine does path mtu discovery as defined in RFC1191.
 */
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static void do_pmtu_discovery(struct sock *sk, struct iphdr *iph, u32 mtu)
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{
	struct dst_entry *dst;
	struct inet_sock *inet = inet_sk(sk);

	/* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs
	 * send out by Linux are always <576bytes so they should go through
	 * unfragmented).
	 */
	if (sk->sk_state == TCP_LISTEN)
		return;

	/* We don't check in the destentry if pmtu discovery is forbidden
	 * on this route. We just assume that no packet_to_big packets
	 * are send back when pmtu discovery is not active.
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	 * There is a small race when the user changes this flag in the
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	 * route, but I think that's acceptable.
	 */
	if ((dst = __sk_dst_check(sk, 0)) == NULL)
		return;

	dst->ops->update_pmtu(dst, mtu);

	/* Something is about to be wrong... Remember soft error
	 * for the case, if this connection will not able to recover.
	 */
	if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst))
		sk->sk_err_soft = EMSGSIZE;

	mtu = dst_mtu(dst);

	if (inet->pmtudisc != IP_PMTUDISC_DONT &&
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	    inet_csk(sk)->icsk_pmtu_cookie > mtu) {
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		tcp_sync_mss(sk, mtu);

		/* Resend the TCP packet because it's
		 * clear that the old packet has been
		 * dropped. This is the new "fast" path mtu
		 * discovery.
		 */
		tcp_simple_retransmit(sk);
	} /* else let the usual retransmit timer handle it */
}

/*
 * This routine is called by the ICMP module when it gets some
 * sort of error condition.  If err < 0 then the socket should
 * be closed and the error returned to the user.  If err > 0
 * it's just the icmp type << 8 | icmp code.  After adjustment
 * header points to the first 8 bytes of the tcp header.  We need
 * to find the appropriate port.
 *
 * The locking strategy used here is very "optimistic". When
 * someone else accesses the socket the ICMP is just dropped
 * and for some paths there is no check at all.
 * A more general error queue to queue errors for later handling
 * is probably better.
 *
 */

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void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
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{
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	struct iphdr *iph = (struct iphdr *)icmp_skb->data;
	struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2));
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	struct inet_connection_sock *icsk;
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	struct tcp_sock *tp;
	struct inet_sock *inet;
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	const int type = icmp_hdr(icmp_skb)->type;
	const int code = icmp_hdr(icmp_skb)->code;
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	struct sock *sk;
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	struct sk_buff *skb;
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	__u32 seq;
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	__u32 remaining;
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	int err;
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	struct net *net = dev_net(icmp_skb->dev);
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	if (icmp_skb->len < (iph->ihl << 2) + 8) {
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		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
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		return;
	}

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	sk = inet_lookup(net, &tcp_hashinfo, iph->daddr, th->dest,
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			iph->saddr, th->source, inet_iif(icmp_skb));
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	if (!sk) {
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		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
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		return;
	}
	if (sk->sk_state == TCP_TIME_WAIT) {
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		inet_twsk_put(inet_twsk(sk));
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		return;
	}

	bh_lock_sock(sk);
	/* If too many ICMPs get dropped on busy
	 * servers this needs to be solved differently.
	 */
	if (sock_owned_by_user(sk))
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		NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
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	if (sk->sk_state == TCP_CLOSE)
		goto out;

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	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
		goto out;
	}

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

	switch (type) {
	case ICMP_SOURCE_QUENCH:
		/* Just silently ignore these. */
		goto out;
	case ICMP_PARAMETERPROB:
		err = EPROTO;
		break;
	case ICMP_DEST_UNREACH:
		if (code > NR_ICMP_UNREACH)
			goto out;

		if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */
			if (!sock_owned_by_user(sk))
				do_pmtu_discovery(sk, iph, info);
			goto out;
		}

		err = icmp_err_convert[code].errno;
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		/* check if icmp_skb allows revert of backoff
		 * (see draft-zimmermann-tcp-lcd) */
		if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH)
			break;
		if (seq != tp->snd_una  || !icsk->icsk_retransmits ||
		    !icsk->icsk_backoff)
			break;

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		if (sock_owned_by_user(sk))
			break;

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		icsk->icsk_backoff--;
		inet_csk(sk)->icsk_rto = __tcp_set_rto(tp) <<
					 icsk->icsk_backoff;
		tcp_bound_rto(sk);

		skb = tcp_write_queue_head(sk);
		BUG_ON(!skb);

		remaining = icsk->icsk_rto - min(icsk->icsk_rto,
				tcp_time_stamp - TCP_SKB_CB(skb)->when);

		if (remaining) {
			inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
						  remaining, TCP_RTO_MAX);
		} else {
			/* RTO revert clocked out retransmission.
			 * Will retransmit now */
			tcp_retransmit_timer(sk);
		}

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		break;
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	default:
		goto out;
	}

	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 = inet_csk_search_req(sk, &prev, th->dest,
					  iph->daddr, iph->saddr);
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		if (!req)
			goto out;

		/* ICMPs are not backlogged, hence we cannot get
		   an established socket here.
		 */
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		WARN_ON(req->sk);
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		if (seq != tcp_rsk(req)->snt_isn) {
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			NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
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			goto out;
		}

		/*
		 * Still in SYN_RECV, just remove it silently.
		 * There is no good way to pass the error to the newly
		 * created socket, and POSIX does not want network
		 * errors returned from accept().
		 */
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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 f.e. if SYNs crossed.
			     */
		if (!sock_owned_by_user(sk)) {
			sk->sk_err = err;

			sk->sk_error_report(sk);

			tcp_done(sk);
		} else {
			sk->sk_err_soft = err;
		}
		goto out;
	}

	/* If we've already connected we will keep trying
	 * until we time out, or the user gives up.
	 *
	 * rfc1122 4.2.3.9 allows to consider as hard errors
	 * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too,
	 * but it is obsoleted by pmtu discovery).
	 *
	 * Note, that in modern internet, where routing is unreliable
	 * and in each dark corner broken firewalls sit, sending random
	 * errors ordered by their masters even this two messages finally lose
	 * their original sense (even Linux sends invalid PORT_UNREACHs)
	 *
	 * Now we are in compliance with RFCs.
	 *							--ANK (980905)
	 */

	inet = inet_sk(sk);
	if (!sock_owned_by_user(sk) && inet->recverr) {
		sk->sk_err = err;
		sk->sk_error_report(sk);
	} else	{ /* Only an error on timeout */
		sk->sk_err_soft = err;
	}

out:
	bh_unlock_sock(sk);
	sock_put(sk);
}

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static void __tcp_v4_send_check(struct sk_buff *skb,
				__be32 saddr, __be32 daddr)
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{
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	struct tcphdr *th = tcp_hdr(skb);
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	if (skb->ip_summed == CHECKSUM_PARTIAL) {
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		th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
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		skb->csum_start = skb_transport_header(skb) - skb->head;
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		skb->csum_offset = offsetof(struct tcphdr, check);
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	} else {
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		th->check = tcp_v4_check(skb->len, saddr, daddr,
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					 csum_partial(th,
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						      th->doff << 2,
						      skb->csum));
	}
}

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/* This routine computes an IPv4 TCP checksum. */
542
void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
543 544 545 546 547
{
	struct inet_sock *inet = inet_sk(sk);

	__tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
}
E
Eric Dumazet 已提交
548
EXPORT_SYMBOL(tcp_v4_send_check);
549

550 551
int tcp_v4_gso_send_check(struct sk_buff *skb)
{
552
	const struct iphdr *iph;
553 554 555 556 557
	struct tcphdr *th;

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

558
	iph = ip_hdr(skb);
559
	th = tcp_hdr(skb);
560 561

	th->check = 0;
562
	skb->ip_summed = CHECKSUM_PARTIAL;
563
	__tcp_v4_send_check(skb, iph->saddr, iph->daddr);
564 565 566
	return 0;
}

L
Linus Torvalds 已提交
567 568 569 570 571 572 573 574 575 576 577 578 579
/*
 *	This routine will send an RST to the other tcp.
 *
 *	Someone asks: why I NEVER use socket parameters (TOS, TTL etc.)
 *		      for reset.
 *	Answer: if a packet caused RST, it is not for a socket
 *		existing in our system, if it is matched to a socket,
 *		it is just duplicate segment or bug in other side's TCP.
 *		So that we build reply only basing on parameters
 *		arrived with segment.
 *	Exception: precedence violation. We do not implement it in any case.
 */

580
static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
581
{
582
	struct tcphdr *th = tcp_hdr(skb);
583 584 585
	struct {
		struct tcphdr th;
#ifdef CONFIG_TCP_MD5SIG
586
		__be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
587 588
#endif
	} rep;
L
Linus Torvalds 已提交
589
	struct ip_reply_arg arg;
590 591 592
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
593
	struct net *net;
L
Linus Torvalds 已提交
594 595 596 597 598

	/* Never send a reset in response to a reset. */
	if (th->rst)
		return;

E
Eric Dumazet 已提交
599
	if (skb_rtable(skb)->rt_type != RTN_LOCAL)
L
Linus Torvalds 已提交
600 601 602
		return;

	/* Swap the send and the receive. */
603 604 605 606 607
	memset(&rep, 0, sizeof(rep));
	rep.th.dest   = th->source;
	rep.th.source = th->dest;
	rep.th.doff   = sizeof(struct tcphdr) / 4;
	rep.th.rst    = 1;
L
Linus Torvalds 已提交
608 609

	if (th->ack) {
610
		rep.th.seq = th->ack_seq;
L
Linus Torvalds 已提交
611
	} else {
612 613 614
		rep.th.ack = 1;
		rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin +
				       skb->len - (th->doff << 2));
L
Linus Torvalds 已提交
615 616
	}

617
	memset(&arg, 0, sizeof(arg));
618 619 620 621
	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);

#ifdef CONFIG_TCP_MD5SIG
622
	key = sk ? tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr) : NULL;
623 624 625 626 627 628 629 630 631
	if (key) {
		rep.opt[0] = htonl((TCPOPT_NOP << 24) |
				   (TCPOPT_NOP << 16) |
				   (TCPOPT_MD5SIG << 8) |
				   TCPOLEN_MD5SIG);
		/* Update length and the length the header thinks exists */
		arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
		rep.th.doff = arg.iov[0].iov_len / 4;

632
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
633 634
				     key, ip_hdr(skb)->saddr,
				     ip_hdr(skb)->daddr, &rep.th);
635 636
	}
#endif
637 638
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
639
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
L
Linus Torvalds 已提交
640
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
641
	arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
L
Linus Torvalds 已提交
642

E
Eric Dumazet 已提交
643
	net = dev_net(skb_dst(skb)->dev);
644
	ip_send_reply(net->ipv4.tcp_sock, skb,
645
		      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
646

647 648
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
L
Linus Torvalds 已提交
649 650 651 652 653 654
}

/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
   outside socket context is ugly, certainly. What can I do?
 */

655 656
static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
			    u32 win, u32 ts, int oif,
657 658
			    struct tcp_md5sig_key *key,
			    int reply_flags)
L
Linus Torvalds 已提交
659
{
660
	struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
661 662
	struct {
		struct tcphdr th;
663
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
664
#ifdef CONFIG_TCP_MD5SIG
665
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
666 667
#endif
			];
L
Linus Torvalds 已提交
668 669
	} rep;
	struct ip_reply_arg arg;
E
Eric Dumazet 已提交
670
	struct net *net = dev_net(skb_dst(skb)->dev);
L
Linus Torvalds 已提交
671 672

	memset(&rep.th, 0, sizeof(struct tcphdr));
673
	memset(&arg, 0, sizeof(arg));
L
Linus Torvalds 已提交
674 675 676 677

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
	if (ts) {
678 679 680 681 682
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
		rep.opt[1] = htonl(tcp_time_stamp);
		rep.opt[2] = htonl(ts);
683
		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
684 685 686 687 688 689 690 691 692 693 694
	}

	/* Swap the send and the receive. */
	rep.th.dest    = th->source;
	rep.th.source  = th->dest;
	rep.th.doff    = arg.iov[0].iov_len / 4;
	rep.th.seq     = htonl(seq);
	rep.th.ack_seq = htonl(ack);
	rep.th.ack     = 1;
	rep.th.window  = htons(win);

695 696 697 698 699 700 701 702 703 704 705
#ifdef CONFIG_TCP_MD5SIG
	if (key) {
		int offset = (ts) ? 3 : 0;

		rep.opt[offset++] = htonl((TCPOPT_NOP << 24) |
					  (TCPOPT_NOP << 16) |
					  (TCPOPT_MD5SIG << 8) |
					  TCPOLEN_MD5SIG);
		arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED;
		rep.th.doff = arg.iov[0].iov_len/4;

706
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
707 708
				    key, ip_hdr(skb)->saddr,
				    ip_hdr(skb)->daddr, &rep.th);
709 710
	}
#endif
711
	arg.flags = reply_flags;
712 713
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
L
Linus Torvalds 已提交
714 715
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
716 717
	if (oif)
		arg.bound_dev_if = oif;
L
Linus Torvalds 已提交
718

719
	ip_send_reply(net->ipv4.tcp_sock, skb,
720
		      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
721

722
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
L
Linus Torvalds 已提交
723 724 725 726
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
727
	struct inet_timewait_sock *tw = inet_twsk(sk);
728
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
729

730
	tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
731
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
732 733
			tcptw->tw_ts_recent,
			tw->tw_bound_dev_if,
734 735
			tcp_twsk_md5_key(tcptw),
			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0
736
			);
L
Linus Torvalds 已提交
737

738
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
739 740
}

741
static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
742
				  struct request_sock *req)
L
Linus Torvalds 已提交
743
{
744
	tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
745
			tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
746 747
			req->ts_recent,
			0,
748 749
			tcp_v4_md5_do_lookup(sk, ip_hdr(skb)->daddr),
			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0);
L
Linus Torvalds 已提交
750 751 752
}

/*
753
 *	Send a SYN-ACK after having received a SYN.
754
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
755 756
 *	socket.
 */
757 758 759
static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
			      struct request_sock *req,
			      struct request_values *rvp)
L
Linus Torvalds 已提交
760
{
761
	const struct inet_request_sock *ireq = inet_rsk(req);
L
Linus Torvalds 已提交
762 763 764 765
	int err = -1;
	struct sk_buff * skb;

	/* First, grab a route. */
766
	if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
767
		return -1;
L
Linus Torvalds 已提交
768

769
	skb = tcp_make_synack(sk, dst, req, rvp);
L
Linus Torvalds 已提交
770 771

	if (skb) {
772
		__tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
L
Linus Torvalds 已提交
773

774 775 776
		err = ip_build_and_send_pkt(skb, sk, ireq->loc_addr,
					    ireq->rmt_addr,
					    ireq->opt);
777
		err = net_xmit_eval(err);
L
Linus Torvalds 已提交
778 779 780 781 782 783
	}

	dst_release(dst);
	return err;
}

784
static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
785
			      struct request_values *rvp)
786
{
787 788
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
	return tcp_v4_send_synack(sk, NULL, req, rvp);
789 790
}

L
Linus Torvalds 已提交
791
/*
792
 *	IPv4 request_sock destructor.
L
Linus Torvalds 已提交
793
 */
794
static void tcp_v4_reqsk_destructor(struct request_sock *req)
L
Linus Torvalds 已提交
795
{
J
Jesper Juhl 已提交
796
	kfree(inet_rsk(req)->opt);
L
Linus Torvalds 已提交
797 798
}

799
static void syn_flood_warning(const struct sk_buff *skb)
L
Linus Torvalds 已提交
800
{
801
	const char *msg;
L
Linus Torvalds 已提交
802

803 804 805 806
#ifdef CONFIG_SYN_COOKIES
	if (sysctl_tcp_syncookies)
		msg = "Sending cookies";
	else
807
#endif
808 809 810 811 812
		msg = "Dropping request";

	pr_info("TCP: Possible SYN flooding on port %d. %s.\n",
				ntohs(tcp_hdr(skb)->dest), msg);
}
L
Linus Torvalds 已提交
813 814

/*
815
 * Save and compile IPv4 options into the request_sock if needed.
L
Linus Torvalds 已提交
816
 */
S
Stephen Hemminger 已提交
817 818
static struct ip_options *tcp_v4_save_options(struct sock *sk,
					      struct sk_buff *skb)
L
Linus Torvalds 已提交
819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835
{
	struct ip_options *opt = &(IPCB(skb)->opt);
	struct ip_options *dopt = NULL;

	if (opt && opt->optlen) {
		int opt_size = optlength(opt);
		dopt = kmalloc(opt_size, GFP_ATOMIC);
		if (dopt) {
			if (ip_options_echo(dopt, skb)) {
				kfree(dopt);
				dopt = NULL;
			}
		}
	}
	return dopt;
}

836 837 838 839 840 841 842 843
#ifdef CONFIG_TCP_MD5SIG
/*
 * RFC2385 MD5 checksumming requires a mapping of
 * IP address->MD5 Key.
 * We need to maintain these in the sk structure.
 */

/* Find the Key structure for an address.  */
844 845
static struct tcp_md5sig_key *
			tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
846 847 848 849 850 851 852 853
{
	struct tcp_sock *tp = tcp_sk(sk);
	int i;

	if (!tp->md5sig_info || !tp->md5sig_info->entries4)
		return NULL;
	for (i = 0; i < tp->md5sig_info->entries4; i++) {
		if (tp->md5sig_info->keys4[i].addr == addr)
854
			return &tp->md5sig_info->keys4[i].base;
855 856 857 858 859 860 861
	}
	return NULL;
}

struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
					 struct sock *addr_sk)
{
E
Eric Dumazet 已提交
862
	return tcp_v4_md5_do_lookup(sk, inet_sk(addr_sk)->inet_daddr);
863 864 865
}
EXPORT_SYMBOL(tcp_v4_md5_lookup);

A
Adrian Bunk 已提交
866 867
static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
						      struct request_sock *req)
868 869 870 871 872 873 874 875 876
{
	return tcp_v4_md5_do_lookup(sk, inet_rsk(req)->rmt_addr);
}

/* This can be called on a newly created socket, from other files */
int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
		      u8 *newkey, u8 newkeylen)
{
	/* Add Key to the list */
877
	struct tcp_md5sig_key *key;
878 879 880
	struct tcp_sock *tp = tcp_sk(sk);
	struct tcp4_md5sig_key *keys;

881
	key = tcp_v4_md5_do_lookup(sk, addr);
882 883
	if (key) {
		/* Pre-existing entry - just update that one. */
884 885 886
		kfree(key->key);
		key->key = newkey;
		key->keylen = newkeylen;
887
	} else {
888 889
		struct tcp_md5sig_info *md5sig;

890
		if (!tp->md5sig_info) {
891 892
			tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info),
						  GFP_ATOMIC);
893 894 895 896
			if (!tp->md5sig_info) {
				kfree(newkey);
				return -ENOMEM;
			}
E
Eric Dumazet 已提交
897
			sk_nocaps_add(sk, NETIF_F_GSO_MASK);
898
		}
899
		if (tcp_alloc_md5sig_pool(sk) == NULL) {
900 901 902
			kfree(newkey);
			return -ENOMEM;
		}
903 904 905 906
		md5sig = tp->md5sig_info;

		if (md5sig->alloced4 == md5sig->entries4) {
			keys = kmalloc((sizeof(*keys) *
907
					(md5sig->entries4 + 1)), GFP_ATOMIC);
908 909 910 911 912 913
			if (!keys) {
				kfree(newkey);
				tcp_free_md5sig_pool();
				return -ENOMEM;
			}

914 915 916
			if (md5sig->entries4)
				memcpy(keys, md5sig->keys4,
				       sizeof(*keys) * md5sig->entries4);
917 918

			/* Free old key list, and reference new one */
919
			kfree(md5sig->keys4);
920 921
			md5sig->keys4 = keys;
			md5sig->alloced4++;
922
		}
923
		md5sig->entries4++;
924 925 926
		md5sig->keys4[md5sig->entries4 - 1].addr        = addr;
		md5sig->keys4[md5sig->entries4 - 1].base.key    = newkey;
		md5sig->keys4[md5sig->entries4 - 1].base.keylen = newkeylen;
927 928 929 930 931 932 933 934
	}
	return 0;
}
EXPORT_SYMBOL(tcp_v4_md5_do_add);

static int tcp_v4_md5_add_func(struct sock *sk, struct sock *addr_sk,
			       u8 *newkey, u8 newkeylen)
{
E
Eric Dumazet 已提交
935
	return tcp_v4_md5_do_add(sk, inet_sk(addr_sk)->inet_daddr,
936 937 938 939 940 941 942 943 944 945 946
				 newkey, newkeylen);
}

int tcp_v4_md5_do_del(struct sock *sk, __be32 addr)
{
	struct tcp_sock *tp = tcp_sk(sk);
	int i;

	for (i = 0; i < tp->md5sig_info->entries4; i++) {
		if (tp->md5sig_info->keys4[i].addr == addr) {
			/* Free the key */
947
			kfree(tp->md5sig_info->keys4[i].base.key);
948 949 950 951 952
			tp->md5sig_info->entries4--;

			if (tp->md5sig_info->entries4 == 0) {
				kfree(tp->md5sig_info->keys4);
				tp->md5sig_info->keys4 = NULL;
953
				tp->md5sig_info->alloced4 = 0;
954
			} else if (tp->md5sig_info->entries4 != i) {
955
				/* Need to do some manipulation */
956 957 958 959
				memmove(&tp->md5sig_info->keys4[i],
					&tp->md5sig_info->keys4[i+1],
					(tp->md5sig_info->entries4 - i) *
					 sizeof(struct tcp4_md5sig_key));
960 961 962 963 964 965 966 967 968
			}
			tcp_free_md5sig_pool();
			return 0;
		}
	}
	return -ENOENT;
}
EXPORT_SYMBOL(tcp_v4_md5_do_del);

969
static void tcp_v4_clear_md5_list(struct sock *sk)
970 971 972 973 974 975 976 977 978 979
{
	struct tcp_sock *tp = tcp_sk(sk);

	/* Free each key, then the set of key keys,
	 * the crypto element, and then decrement our
	 * hold on the last resort crypto.
	 */
	if (tp->md5sig_info->entries4) {
		int i;
		for (i = 0; i < tp->md5sig_info->entries4; i++)
980
			kfree(tp->md5sig_info->keys4[i].base.key);
981 982 983 984 985 986 987 988 989 990
		tp->md5sig_info->entries4 = 0;
		tcp_free_md5sig_pool();
	}
	if (tp->md5sig_info->keys4) {
		kfree(tp->md5sig_info->keys4);
		tp->md5sig_info->keys4 = NULL;
		tp->md5sig_info->alloced4  = 0;
	}
}

991 992
static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
				 int optlen)
993 994 995 996 997 998 999 1000
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;
	u8 *newkey;

	if (optlen < sizeof(cmd))
		return -EINVAL;

1001
	if (copy_from_user(&cmd, optval, sizeof(cmd)))
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017
		return -EFAULT;

	if (sin->sin_family != AF_INET)
		return -EINVAL;

	if (!cmd.tcpm_key || !cmd.tcpm_keylen) {
		if (!tcp_sk(sk)->md5sig_info)
			return -ENOENT;
		return tcp_v4_md5_do_del(sk, sin->sin_addr.s_addr);
	}

	if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
		return -EINVAL;

	if (!tcp_sk(sk)->md5sig_info) {
		struct tcp_sock *tp = tcp_sk(sk);
1018
		struct tcp_md5sig_info *p;
1019

1020
		p = kzalloc(sizeof(*p), sk->sk_allocation);
1021 1022 1023 1024
		if (!p)
			return -EINVAL;

		tp->md5sig_info = p;
E
Eric Dumazet 已提交
1025
		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
1026 1027
	}

1028
	newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
1029 1030 1031 1032 1033 1034
	if (!newkey)
		return -ENOMEM;
	return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,
				 newkey, cmd.tcpm_keylen);
}

1035 1036
static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
					__be32 daddr, __be32 saddr, int nbytes)
1037 1038
{
	struct tcp4_pseudohdr *bp;
1039
	struct scatterlist sg;
1040 1041 1042 1043

	bp = &hp->md5_blk.ip4;

	/*
1044
	 * 1. the TCP pseudo-header (in the order: source IP address,
1045 1046 1047 1048 1049 1050
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
1051
	bp->protocol = IPPROTO_TCP;
1052
	bp->len = cpu_to_be16(nbytes);
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
	sg_init_one(&sg, bp, sizeof(*bp));
	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
}

static int tcp_v4_md5_hash_hdr(char *md5_hash, struct tcp_md5sig_key *key,
			       __be32 daddr, __be32 saddr, struct tcphdr *th)
{
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;
	desc = &hp->md5_desc;

	if (crypto_hash_init(desc))
		goto clear_hash;
	if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2))
		goto clear_hash;
	if (tcp_md5_hash_header(hp, th))
		goto clear_hash;
	if (tcp_md5_hash_key(hp, key))
		goto clear_hash;
	if (crypto_hash_final(desc, md5_hash))
1078 1079 1080 1081
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;
1082

1083 1084 1085 1086
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
1087
	return 1;
1088 1089
}

1090 1091 1092
int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
			struct sock *sk, struct request_sock *req,
			struct sk_buff *skb)
1093
{
1094 1095 1096
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
	struct tcphdr *th = tcp_hdr(skb);
1097 1098 1099
	__be32 saddr, daddr;

	if (sk) {
E
Eric Dumazet 已提交
1100 1101
		saddr = inet_sk(sk)->inet_saddr;
		daddr = inet_sk(sk)->inet_daddr;
1102 1103 1104
	} else if (req) {
		saddr = inet_rsk(req)->loc_addr;
		daddr = inet_rsk(req)->rmt_addr;
1105
	} else {
1106 1107 1108
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
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

	hp = tcp_get_md5sig_pool();
	if (!hp)
		goto clear_hash_noput;
	desc = &hp->md5_desc;

	if (crypto_hash_init(desc))
		goto clear_hash;

	if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len))
		goto clear_hash;
	if (tcp_md5_hash_header(hp, th))
		goto clear_hash;
	if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2))
		goto clear_hash;
	if (tcp_md5_hash_key(hp, key))
		goto clear_hash;
	if (crypto_hash_final(desc, md5_hash))
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;

clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
	return 1;
1138
}
1139
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1140

1141
static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152
{
	/*
	 * This gets called for each TCP segment that arrives
	 * so we want to be efficient.
	 * We have 3 drop cases:
	 * o No MD5 hash and one expected.
	 * o MD5 hash and we're not expecting one.
	 * o MD5 hash and its wrong.
	 */
	__u8 *hash_location = NULL;
	struct tcp_md5sig_key *hash_expected;
1153
	const struct iphdr *iph = ip_hdr(skb);
1154
	struct tcphdr *th = tcp_hdr(skb);
1155 1156 1157 1158
	int genhash;
	unsigned char newhash[16];

	hash_expected = tcp_v4_md5_do_lookup(sk, iph->saddr);
1159
	hash_location = tcp_parse_md5sig_option(th);
1160 1161 1162 1163 1164 1165

	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
		return 0;

	if (hash_expected && !hash_location) {
1166
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
1167 1168 1169 1170
		return 1;
	}

	if (!hash_expected && hash_location) {
1171
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
1172 1173 1174 1175 1176 1177
		return 1;
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
1178 1179 1180
	genhash = tcp_v4_md5_hash_skb(newhash,
				      hash_expected,
				      NULL, NULL, skb);
1181 1182 1183

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
		if (net_ratelimit()) {
1184 1185 1186
			printk(KERN_INFO "MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
			       &iph->saddr, ntohs(th->source),
			       &iph->daddr, ntohs(th->dest),
1187 1188 1189 1190 1191 1192 1193 1194 1195
			       genhash ? " tcp_v4_calc_md5_hash failed" : "");
		}
		return 1;
	}
	return 0;
}

#endif

1196
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1197
	.family		=	PF_INET,
1198
	.obj_size	=	sizeof(struct tcp_request_sock),
1199
	.rtx_syn_ack	=	tcp_v4_rtx_synack,
1200 1201
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1202
	.send_reset	=	tcp_v4_send_reset,
1203
	.syn_ack_timeout = 	tcp_syn_ack_timeout,
L
Linus Torvalds 已提交
1204 1205
};

1206
#ifdef CONFIG_TCP_MD5SIG
1207
static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1208
	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
1209
	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1210
};
1211
#endif
1212

L
Linus Torvalds 已提交
1213 1214
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
1215
	struct tcp_extend_values tmp_ext;
L
Linus Torvalds 已提交
1216
	struct tcp_options_received tmp_opt;
1217
	u8 *hash_location;
1218
	struct request_sock *req;
1219
	struct inet_request_sock *ireq;
1220
	struct tcp_sock *tp = tcp_sk(sk);
1221
	struct dst_entry *dst = NULL;
1222 1223
	__be32 saddr = ip_hdr(skb)->saddr;
	__be32 daddr = ip_hdr(skb)->daddr;
L
Linus Torvalds 已提交
1224 1225 1226 1227 1228 1229 1230 1231
	__u32 isn = TCP_SKB_CB(skb)->when;
#ifdef CONFIG_SYN_COOKIES
	int want_cookie = 0;
#else
#define want_cookie 0 /* Argh, why doesn't gcc optimize this :( */
#endif

	/* Never answer to SYNs send to broadcast or multicast */
E
Eric Dumazet 已提交
1232
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
L
Linus Torvalds 已提交
1233 1234 1235 1236 1237 1238
		goto drop;

	/* TW buckets are converted to open requests without
	 * limitations, they conserve resources and peer is
	 * evidently real one.
	 */
1239
	if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
1240 1241
		if (net_ratelimit())
			syn_flood_warning(skb);
L
Linus Torvalds 已提交
1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254
#ifdef CONFIG_SYN_COOKIES
		if (sysctl_tcp_syncookies) {
			want_cookie = 1;
		} else
#endif
		goto drop;
	}

	/* Accept backlog is full. If we have already queued enough
	 * of warm entries in syn queue, drop request. It is better than
	 * clogging syn queue with openreqs with exponentially increasing
	 * timeout.
	 */
1255
	if (sk_acceptq_is_full(sk) && inet_csk_reqsk_queue_young(sk) > 1)
L
Linus Torvalds 已提交
1256 1257
		goto drop;

1258
	req = inet_reqsk_alloc(&tcp_request_sock_ops);
L
Linus Torvalds 已提交
1259 1260 1261
	if (!req)
		goto drop;

1262 1263 1264 1265
#ifdef CONFIG_TCP_MD5SIG
	tcp_rsk(req)->af_specific = &tcp_request_sock_ipv4_ops;
#endif

L
Linus Torvalds 已提交
1266
	tcp_clear_options(&tmp_opt);
1267
	tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
1268
	tmp_opt.user_mss  = tp->rx_opt.user_mss;
1269
	tcp_parse_options(skb, &tmp_opt, &hash_location, 0);
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284

	if (tmp_opt.cookie_plus > 0 &&
	    tmp_opt.saw_tstamp &&
	    !tp->rx_opt.cookie_out_never &&
	    (sysctl_tcp_cookie_size > 0 ||
	     (tp->cookie_values != NULL &&
	      tp->cookie_values->cookie_desired > 0))) {
		u8 *c;
		u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS];
		int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE;

		if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0)
			goto drop_and_release;

		/* Secret recipe starts with IP addresses */
1285 1286
		*mess++ ^= (__force u32)daddr;
		*mess++ ^= (__force u32)saddr;
L
Linus Torvalds 已提交
1287

1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305
		/* plus variable length Initiator Cookie */
		c = (u8 *)mess;
		while (l-- > 0)
			*c++ ^= *hash_location++;

#ifdef CONFIG_SYN_COOKIES
		want_cookie = 0;	/* not our kind of cookie */
#endif
		tmp_ext.cookie_out_never = 0; /* false */
		tmp_ext.cookie_plus = tmp_opt.cookie_plus;
	} else if (!tp->rx_opt.cookie_in_always) {
		/* redundant indications, but ensure initialization. */
		tmp_ext.cookie_out_never = 1; /* true */
		tmp_ext.cookie_plus = 0;
	} else {
		goto drop_and_release;
	}
	tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always;
L
Linus Torvalds 已提交
1306

1307
	if (want_cookie && !tmp_opt.saw_tstamp)
L
Linus Torvalds 已提交
1308 1309 1310 1311 1312
		tcp_clear_options(&tmp_opt);

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

1313 1314 1315 1316 1317 1318
	ireq = inet_rsk(req);
	ireq->loc_addr = daddr;
	ireq->rmt_addr = saddr;
	ireq->no_srccheck = inet_sk(sk)->transparent;
	ireq->opt = tcp_v4_save_options(sk, skb);

1319
	if (security_inet_conn_request(sk, skb, req))
1320
		goto drop_and_free;
1321

1322
	if (!want_cookie || tmp_opt.tstamp_ok)
1323
		TCP_ECN_create_request(req, tcp_hdr(skb));
L
Linus Torvalds 已提交
1324 1325 1326

	if (want_cookie) {
		isn = cookie_v4_init_sequence(sk, skb, &req->mss);
1327
		req->cookie_ts = tmp_opt.tstamp_ok;
L
Linus Torvalds 已提交
1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340
	} else if (!isn) {
		struct inet_peer *peer = NULL;

		/* VJ's idea. We save last timestamp seen
		 * from the destination in peer table, when entering
		 * state TIME-WAIT, and check against it before
		 * accepting new connection request.
		 *
		 * If "isn" is not zero, this request hit alive
		 * timewait bucket, so that all the necessary checks
		 * are made in the function processing timewait state.
		 */
		if (tmp_opt.saw_tstamp &&
1341
		    tcp_death_row.sysctl_tw_recycle &&
1342
		    (dst = inet_csk_route_req(sk, req)) != NULL &&
L
Linus Torvalds 已提交
1343
		    (peer = rt_get_peer((struct rtable *)dst)) != NULL &&
1344
		    peer->daddr.a4 == saddr) {
1345
			inet_peer_refcheck(peer);
E
Eric Dumazet 已提交
1346
			if ((u32)get_seconds() - peer->tcp_ts_stamp < TCP_PAWS_MSL &&
L
Linus Torvalds 已提交
1347 1348
			    (s32)(peer->tcp_ts - req->ts_recent) >
							TCP_PAWS_WINDOW) {
1349
				NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
1350
				goto drop_and_release;
L
Linus Torvalds 已提交
1351 1352 1353 1354
			}
		}
		/* Kill the following clause, if you dislike this way. */
		else if (!sysctl_tcp_syncookies &&
1355
			 (sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
L
Linus Torvalds 已提交
1356 1357 1358 1359 1360 1361 1362 1363 1364 1365
			  (sysctl_max_syn_backlog >> 2)) &&
			 (!peer || !peer->tcp_ts_stamp) &&
			 (!dst || !dst_metric(dst, RTAX_RTT))) {
			/* Without syncookies last quarter of
			 * backlog is filled with destinations,
			 * proven to be alive.
			 * It means that we continue to communicate
			 * to destinations, already remembered
			 * to the moment of synflood.
			 */
1366 1367
			LIMIT_NETDEBUG(KERN_DEBUG "TCP: drop open request from %pI4/%u\n",
				       &saddr, ntohs(tcp_hdr(skb)->source));
1368
			goto drop_and_release;
L
Linus Torvalds 已提交
1369 1370
		}

1371
		isn = tcp_v4_init_sequence(skb);
L
Linus Torvalds 已提交
1372
	}
1373
	tcp_rsk(req)->snt_isn = isn;
L
Linus Torvalds 已提交
1374

1375 1376
	if (tcp_v4_send_synack(sk, dst, req,
			       (struct request_values *)&tmp_ext) ||
1377
	    want_cookie)
L
Linus Torvalds 已提交
1378 1379
		goto drop_and_free;

1380
	inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
L
Linus Torvalds 已提交
1381 1382
	return 0;

1383 1384
drop_and_release:
	dst_release(dst);
L
Linus Torvalds 已提交
1385
drop_and_free:
1386
	reqsk_free(req);
L
Linus Torvalds 已提交
1387 1388 1389
drop:
	return 0;
}
E
Eric Dumazet 已提交
1390
EXPORT_SYMBOL(tcp_v4_conn_request);
L
Linus Torvalds 已提交
1391 1392 1393 1394 1395 1396 1397


/*
 * The three way handshake has completed - we got a valid synack -
 * now create the new socket.
 */
struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1398
				  struct request_sock *req,
L
Linus Torvalds 已提交
1399 1400
				  struct dst_entry *dst)
{
1401
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1402 1403 1404
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1405 1406 1407
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
L
Linus Torvalds 已提交
1408 1409 1410 1411

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

1412
	if (!dst && (dst = inet_csk_route_req(sk, req)) == NULL)
L
Linus Torvalds 已提交
1413 1414 1415 1416
		goto exit;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
1417
		goto exit_nonewsk;
L
Linus Torvalds 已提交
1418

1419
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1420
	sk_setup_caps(newsk, dst);
L
Linus Torvalds 已提交
1421 1422 1423

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1424
	ireq		      = inet_rsk(req);
E
Eric Dumazet 已提交
1425 1426 1427
	newinet->inet_daddr   = ireq->rmt_addr;
	newinet->inet_rcv_saddr = ireq->loc_addr;
	newinet->inet_saddr	      = ireq->loc_addr;
1428 1429
	newinet->opt	      = ireq->opt;
	ireq->opt	      = NULL;
1430
	newinet->mc_index     = inet_iif(skb);
1431
	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
1432
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
L
Linus Torvalds 已提交
1433
	if (newinet->opt)
1434
		inet_csk(newsk)->icsk_ext_hdr_len = newinet->opt->optlen;
E
Eric Dumazet 已提交
1435
	newinet->inet_id = newtp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
1436

J
John Heffner 已提交
1437
	tcp_mtup_init(newsk);
L
Linus Torvalds 已提交
1438 1439
	tcp_sync_mss(newsk, dst_mtu(dst));
	newtp->advmss = dst_metric(dst, RTAX_ADVMSS);
1440 1441 1442 1443
	if (tcp_sk(sk)->rx_opt.user_mss &&
	    tcp_sk(sk)->rx_opt.user_mss < newtp->advmss)
		newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;

L
Linus Torvalds 已提交
1444 1445
	tcp_initialize_rcv_mss(newsk);

1446 1447
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
E
Eric Dumazet 已提交
1448 1449
	key = tcp_v4_md5_do_lookup(sk, newinet->inet_daddr);
	if (key != NULL) {
1450 1451 1452 1453 1454 1455
		/*
		 * We're using one, so create a matching key
		 * on the newsk structure. If we fail to get
		 * memory, then we end up not copying the key
		 * across. Shucks.
		 */
1456 1457
		char *newkey = kmemdup(key->key, key->keylen, GFP_ATOMIC);
		if (newkey != NULL)
E
Eric Dumazet 已提交
1458
			tcp_v4_md5_do_add(newsk, newinet->inet_daddr,
1459
					  newkey, key->keylen);
E
Eric Dumazet 已提交
1460
		sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1461 1462 1463
	}
#endif

1464 1465 1466 1467
	if (__inet_inherit_port(sk, newsk) < 0) {
		sock_put(newsk);
		goto exit;
	}
1468
	__inet_hash_nolisten(newsk, NULL);
L
Linus Torvalds 已提交
1469 1470 1471 1472

	return newsk;

exit_overflow:
1473
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1474 1475
exit_nonewsk:
	dst_release(dst);
L
Linus Torvalds 已提交
1476
exit:
1477
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1478 1479
	return NULL;
}
E
Eric Dumazet 已提交
1480
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
L
Linus Torvalds 已提交
1481 1482 1483

static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
{
1484
	struct tcphdr *th = tcp_hdr(skb);
1485
	const struct iphdr *iph = ip_hdr(skb);
L
Linus Torvalds 已提交
1486
	struct sock *nsk;
1487
	struct request_sock **prev;
L
Linus Torvalds 已提交
1488
	/* Find possible connection requests. */
1489 1490
	struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
						       iph->saddr, iph->daddr);
L
Linus Torvalds 已提交
1491 1492 1493
	if (req)
		return tcp_check_req(sk, skb, req, prev);

1494
	nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1495
			th->source, iph->daddr, th->dest, inet_iif(skb));
L
Linus Torvalds 已提交
1496 1497 1498 1499 1500 1501

	if (nsk) {
		if (nsk->sk_state != TCP_TIME_WAIT) {
			bh_lock_sock(nsk);
			return nsk;
		}
1502
		inet_twsk_put(inet_twsk(nsk));
L
Linus Torvalds 已提交
1503 1504 1505 1506
		return NULL;
	}

#ifdef CONFIG_SYN_COOKIES
1507
	if (!th->syn)
L
Linus Torvalds 已提交
1508 1509 1510 1511 1512
		sk = cookie_v4_check(sk, skb, &(IPCB(skb)->opt));
#endif
	return sk;
}

1513
static __sum16 tcp_v4_checksum_init(struct sk_buff *skb)
L
Linus Torvalds 已提交
1514
{
1515 1516
	const struct iphdr *iph = ip_hdr(skb);

1517
	if (skb->ip_summed == CHECKSUM_COMPLETE) {
1518 1519
		if (!tcp_v4_check(skb->len, iph->saddr,
				  iph->daddr, skb->csum)) {
1520
			skb->ip_summed = CHECKSUM_UNNECESSARY;
L
Linus Torvalds 已提交
1521
			return 0;
1522
		}
L
Linus Torvalds 已提交
1523
	}
1524

1525
	skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
1526 1527
				       skb->len, IPPROTO_TCP, 0);

L
Linus Torvalds 已提交
1528
	if (skb->len <= 76) {
1529
		return __skb_checksum_complete(skb);
L
Linus Torvalds 已提交
1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544
	}
	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.
 */
int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
{
1545 1546 1547 1548 1549 1550 1551 1552
	struct sock *rsk;
#ifdef CONFIG_TCP_MD5SIG
	/*
	 * We really want to reject the packet as early as possible
	 * if:
	 *  o We're expecting an MD5'd packet and this is no MD5 tcp option
	 *  o There is an MD5 option and we're not expecting one
	 */
1553
	if (tcp_v4_inbound_md5_hash(sk, skb))
1554 1555 1556
		goto discard;
#endif

L
Linus Torvalds 已提交
1557
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1558
		sock_rps_save_rxhash(sk, skb->rxhash);
L
Linus Torvalds 已提交
1559
		TCP_CHECK_TIMER(sk);
1560
		if (tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len)) {
1561
			rsk = sk;
L
Linus Torvalds 已提交
1562
			goto reset;
1563
		}
L
Linus Torvalds 已提交
1564 1565 1566 1567
		TCP_CHECK_TIMER(sk);
		return 0;
	}

1568
	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
L
Linus Torvalds 已提交
1569 1570 1571 1572 1573 1574 1575 1576
		goto csum_err;

	if (sk->sk_state == TCP_LISTEN) {
		struct sock *nsk = tcp_v4_hnd_req(sk, skb);
		if (!nsk)
			goto discard;

		if (nsk != sk) {
1577 1578
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1579
				goto reset;
1580
			}
L
Linus Torvalds 已提交
1581 1582
			return 0;
		}
1583 1584 1585
	} else
		sock_rps_save_rxhash(sk, skb->rxhash);

L
Linus Torvalds 已提交
1586 1587

	TCP_CHECK_TIMER(sk);
1588
	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1589
		rsk = sk;
L
Linus Torvalds 已提交
1590
		goto reset;
1591
	}
L
Linus Torvalds 已提交
1592 1593 1594 1595
	TCP_CHECK_TIMER(sk);
	return 0;

reset:
1596
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1597 1598 1599 1600 1601 1602 1603 1604 1605 1606
discard:
	kfree_skb(skb);
	/* Be careful here. If this function gets more complicated and
	 * gcc suffers from register pressure on the x86, sk (in %ebx)
	 * might be destroyed here. This current version compiles correctly,
	 * but you have been warned.
	 */
	return 0;

csum_err:
1607
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1608 1609
	goto discard;
}
E
Eric Dumazet 已提交
1610
EXPORT_SYMBOL(tcp_v4_do_rcv);
L
Linus Torvalds 已提交
1611 1612 1613 1614 1615 1616 1617

/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
1618
	const struct iphdr *iph;
L
Linus Torvalds 已提交
1619 1620 1621
	struct tcphdr *th;
	struct sock *sk;
	int ret;
1622
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
1623 1624 1625 1626 1627

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

	/* Count it even if it's bad */
1628
	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
L
Linus Torvalds 已提交
1629 1630 1631 1632

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

1633
	th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1634 1635 1636 1637 1638 1639 1640 1641

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

	/* An explanation is required here, I think.
	 * Packet length and doff are validated by header prediction,
S
Stephen Hemminger 已提交
1642
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1643
	 * So, we defer the checks. */
1644
	if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
L
Linus Torvalds 已提交
1645 1646
		goto bad_packet;

1647
	th = tcp_hdr(skb);
1648
	iph = ip_hdr(skb);
L
Linus Torvalds 已提交
1649 1650 1651 1652 1653
	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;
1654
	TCP_SKB_CB(skb)->flags	 = iph->tos;
L
Linus Torvalds 已提交
1655 1656
	TCP_SKB_CB(skb)->sacked	 = 0;

1657
	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
L
Linus Torvalds 已提交
1658 1659 1660
	if (!sk)
		goto no_tcp_socket;

E
Eric Dumazet 已提交
1661 1662 1663 1664
process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

1665 1666
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1667
		goto discard_and_relse;
1668
	}
1669

L
Linus Torvalds 已提交
1670 1671
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1672
	nf_reset(skb);
L
Linus Torvalds 已提交
1673

1674
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1675 1676 1677 1678
		goto discard_and_relse;

	skb->dev = NULL;

1679
	bh_lock_sock_nested(sk);
L
Linus Torvalds 已提交
1680 1681
	ret = 0;
	if (!sock_owned_by_user(sk)) {
C
Chris Leech 已提交
1682 1683 1684
#ifdef CONFIG_NET_DMA
		struct tcp_sock *tp = tcp_sk(sk);
		if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
1685
			tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
C
Chris Leech 已提交
1686
		if (tp->ucopy.dma_chan)
L
Linus Torvalds 已提交
1687
			ret = tcp_v4_do_rcv(sk, skb);
C
Chris Leech 已提交
1688 1689 1690 1691
		else
#endif
		{
			if (!tcp_prequeue(sk, skb))
S
Shan Wei 已提交
1692
				ret = tcp_v4_do_rcv(sk, skb);
C
Chris Leech 已提交
1693
		}
1694
	} else if (unlikely(sk_add_backlog(sk, skb))) {
Z
Zhu Yi 已提交
1695
		bh_unlock_sock(sk);
1696
		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
Z
Zhu Yi 已提交
1697 1698
		goto discard_and_relse;
	}
L
Linus Torvalds 已提交
1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710
	bh_unlock_sock(sk);

	sock_put(sk);

	return ret;

no_tcp_socket:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto discard_it;

	if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
bad_packet:
1711
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1712
	} else {
1713
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1714 1715 1716 1717 1718
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
1719
	return 0;
L
Linus Torvalds 已提交
1720 1721 1722 1723 1724 1725 1726

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1727
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1728 1729 1730 1731
		goto discard_it;
	}

	if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1732
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
1733
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1734 1735
		goto discard_it;
	}
1736
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1737
	case TCP_TW_SYN: {
1738
		struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1739
							&tcp_hashinfo,
1740
							iph->daddr, th->dest,
1741
							inet_iif(skb));
L
Linus Torvalds 已提交
1742
		if (sk2) {
1743 1744
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759
			sk = sk2;
			goto process;
		}
		/* Fall through to ACK */
	}
	case TCP_TW_ACK:
		tcp_v4_timewait_ack(sk, skb);
		break;
	case TCP_TW_RST:
		goto no_tcp_socket;
	case TCP_TW_SUCCESS:;
	}
	goto discard_it;
}

1760
struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it)
L
Linus Torvalds 已提交
1761
{
1762
	struct rtable *rt = (struct rtable *) __sk_dst_get(sk);
L
Linus Torvalds 已提交
1763
	struct inet_sock *inet = inet_sk(sk);
1764
	struct inet_peer *peer;
L
Linus Torvalds 已提交
1765

E
Eric Dumazet 已提交
1766
	if (!rt || rt->rt_dst != inet->inet_daddr) {
1767
		peer = inet_getpeer_v4(inet->inet_daddr, 1);
1768
		*release_it = true;
L
Linus Torvalds 已提交
1769 1770 1771 1772
	} else {
		if (!rt->peer)
			rt_bind_peer(rt, 1);
		peer = rt->peer;
1773
		*release_it = false;
L
Linus Torvalds 已提交
1774 1775
	}

1776
	return peer;
L
Linus Torvalds 已提交
1777
}
1778
EXPORT_SYMBOL(tcp_v4_get_peer);
L
Linus Torvalds 已提交
1779

1780
void *tcp_v4_tw_get_peer(struct sock *sk)
L
Linus Torvalds 已提交
1781
{
1782
	struct inet_timewait_sock *tw = inet_twsk(sk);
L
Linus Torvalds 已提交
1783

1784
	return inet_getpeer_v4(tw->tw_daddr, 1);
L
Linus Torvalds 已提交
1785
}
1786 1787 1788 1789 1790 1791 1792 1793
EXPORT_SYMBOL(tcp_v4_tw_get_peer);

static struct timewait_sock_ops tcp_timewait_sock_ops = {
	.twsk_obj_size	= sizeof(struct tcp_timewait_sock),
	.twsk_unique	= tcp_twsk_unique,
	.twsk_destructor= tcp_twsk_destructor,
	.twsk_getpeer	= tcp_v4_tw_get_peer,
};
L
Linus Torvalds 已提交
1794

1795
const struct inet_connection_sock_af_ops ipv4_specific = {
1796 1797 1798 1799 1800
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
	.conn_request	   = tcp_v4_conn_request,
	.syn_recv_sock	   = tcp_v4_syn_recv_sock,
1801
	.get_peer	   = tcp_v4_get_peer,
1802 1803 1804 1805 1806
	.net_header_len	   = sizeof(struct iphdr),
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.addr2sockaddr	   = inet_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in),
1807
	.bind_conflict	   = inet_csk_bind_conflict,
1808
#ifdef CONFIG_COMPAT
1809 1810
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1811
#endif
L
Linus Torvalds 已提交
1812
};
E
Eric Dumazet 已提交
1813
EXPORT_SYMBOL(ipv4_specific);
L
Linus Torvalds 已提交
1814

1815
#ifdef CONFIG_TCP_MD5SIG
1816
static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1817
	.md5_lookup		= tcp_v4_md5_lookup,
1818
	.calc_md5_hash		= tcp_v4_md5_hash_skb,
1819 1820 1821
	.md5_add		= tcp_v4_md5_add_func,
	.md5_parse		= tcp_v4_parse_md5_keys,
};
1822
#endif
1823

L
Linus Torvalds 已提交
1824 1825 1826 1827 1828
/* NOTE: A lot of things set to zero explicitly by call to
 *       sk_alloc() so need not be done here.
 */
static int tcp_v4_init_sock(struct sock *sk)
{
1829
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1830 1831 1832 1833 1834 1835
	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);

1836
	icsk->icsk_rto = TCP_TIMEOUT_INIT;
L
Linus Torvalds 已提交
1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848
	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.
	 */
I
Ilpo Järvinen 已提交
1849
	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
L
Linus Torvalds 已提交
1850
	tp->snd_cwnd_clamp = ~0;
1851
	tp->mss_cache = TCP_MSS_DEFAULT;
L
Linus Torvalds 已提交
1852 1853

	tp->reordering = sysctl_tcp_reordering;
1854
	icsk->icsk_ca_ops = &tcp_init_congestion_ops;
L
Linus Torvalds 已提交
1855 1856 1857 1858 1859 1860

	sk->sk_state = TCP_CLOSE;

	sk->sk_write_space = sk_stream_write_space;
	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);

1861
	icsk->icsk_af_ops = &ipv4_specific;
1862
	icsk->icsk_sync_mss = tcp_sync_mss;
1863 1864 1865
#ifdef CONFIG_TCP_MD5SIG
	tp->af_specific = &tcp_sock_ipv4_specific;
#endif
L
Linus Torvalds 已提交
1866

1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879
	/* TCP Cookie Transactions */
	if (sysctl_tcp_cookie_size > 0) {
		/* Default, cookies without s_data_payload. */
		tp->cookie_values =
			kzalloc(sizeof(*tp->cookie_values),
				sk->sk_allocation);
		if (tp->cookie_values != NULL)
			kref_init(&tp->cookie_values->kref);
	}
	/* Presumed zeroed, in order of appearance:
	 *	cookie_in_always, cookie_out_never,
	 *	s_data_constant, s_data_in, s_data_out
	 */
L
Linus Torvalds 已提交
1880 1881 1882
	sk->sk_sndbuf = sysctl_tcp_wmem[1];
	sk->sk_rcvbuf = sysctl_tcp_rmem[1];

H
Herbert Xu 已提交
1883
	local_bh_disable();
1884
	percpu_counter_inc(&tcp_sockets_allocated);
H
Herbert Xu 已提交
1885
	local_bh_enable();
L
Linus Torvalds 已提交
1886 1887 1888 1889

	return 0;
}

1890
void tcp_v4_destroy_sock(struct sock *sk)
L
Linus Torvalds 已提交
1891 1892 1893 1894 1895
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1896
	tcp_cleanup_congestion_control(sk);
1897

L
Linus Torvalds 已提交
1898
	/* Cleanup up the write buffer. */
1899
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
1900 1901

	/* Cleans up our, hopefully empty, out_of_order_queue. */
1902
	__skb_queue_purge(&tp->out_of_order_queue);
L
Linus Torvalds 已提交
1903

1904 1905 1906 1907 1908 1909 1910 1911 1912
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
		tcp_v4_clear_md5_list(sk);
		kfree(tp->md5sig_info);
		tp->md5sig_info = NULL;
	}
#endif

C
Chris Leech 已提交
1913 1914
#ifdef CONFIG_NET_DMA
	/* Cleans up our sk_async_wait_queue */
1915
	__skb_queue_purge(&sk->sk_async_wait_queue);
C
Chris Leech 已提交
1916 1917
#endif

L
Linus Torvalds 已提交
1918 1919 1920 1921
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1922
	if (inet_csk(sk)->icsk_bind_hash)
1923
		inet_put_port(sk);
L
Linus Torvalds 已提交
1924 1925 1926 1927 1928 1929 1930 1931 1932

	/*
	 * If sendmsg cached page exists, toss it.
	 */
	if (sk->sk_sndmsg_page) {
		__free_page(sk->sk_sndmsg_page);
		sk->sk_sndmsg_page = NULL;
	}

1933 1934 1935 1936 1937 1938 1939
	/* TCP Cookie Transactions */
	if (tp->cookie_values != NULL) {
		kref_put(&tp->cookie_values->kref,
			 tcp_cookie_values_release);
		tp->cookie_values = NULL;
	}

1940
	percpu_counter_dec(&tcp_sockets_allocated);
L
Linus Torvalds 已提交
1941 1942 1943 1944 1945 1946
}
EXPORT_SYMBOL(tcp_v4_destroy_sock);

#ifdef CONFIG_PROC_FS
/* Proc filesystem TCP sock list dumping. */

1947
static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
L
Linus Torvalds 已提交
1948
{
1949
	return hlist_nulls_empty(head) ? NULL :
1950
		list_entry(head->first, struct inet_timewait_sock, tw_node);
L
Linus Torvalds 已提交
1951 1952
}

1953
static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
L
Linus Torvalds 已提交
1954
{
1955 1956
	return !is_a_nulls(tw->tw_node.next) ?
		hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
L
Linus Torvalds 已提交
1957 1958
}

1959 1960 1961 1962 1963
/*
 * Get next listener socket follow cur.  If cur is NULL, get first socket
 * starting from bucket given in st->bucket; when st->bucket is zero the
 * very first socket in the hash table is returned.
 */
L
Linus Torvalds 已提交
1964 1965
static void *listening_get_next(struct seq_file *seq, void *cur)
{
1966
	struct inet_connection_sock *icsk;
1967
	struct hlist_nulls_node *node;
L
Linus Torvalds 已提交
1968
	struct sock *sk = cur;
1969
	struct inet_listen_hashbucket *ilb;
J
Jianjun Kong 已提交
1970
	struct tcp_iter_state *st = seq->private;
1971
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1972 1973

	if (!sk) {
1974
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
1975
		spin_lock_bh(&ilb->lock);
1976
		sk = sk_nulls_head(&ilb->head);
1977
		st->offset = 0;
L
Linus Torvalds 已提交
1978 1979
		goto get_sk;
	}
1980
	ilb = &tcp_hashinfo.listening_hash[st->bucket];
L
Linus Torvalds 已提交
1981
	++st->num;
1982
	++st->offset;
L
Linus Torvalds 已提交
1983 1984

	if (st->state == TCP_SEQ_STATE_OPENREQ) {
1985
		struct request_sock *req = cur;
L
Linus Torvalds 已提交
1986

1987
		icsk = inet_csk(st->syn_wait_sk);
L
Linus Torvalds 已提交
1988 1989 1990
		req = req->dl_next;
		while (1) {
			while (req) {
1991
				if (req->rsk_ops->family == st->family) {
L
Linus Torvalds 已提交
1992 1993 1994 1995 1996
					cur = req;
					goto out;
				}
				req = req->dl_next;
			}
1997
			st->offset = 0;
1998
			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
L
Linus Torvalds 已提交
1999 2000
				break;
get_req:
2001
			req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
L
Linus Torvalds 已提交
2002 2003 2004
		}
		sk	  = sk_next(st->syn_wait_sk);
		st->state = TCP_SEQ_STATE_LISTENING;
2005
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2006
	} else {
2007
		icsk = inet_csk(sk);
2008 2009
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue))
L
Linus Torvalds 已提交
2010
			goto start_req;
2011
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2012 2013 2014
		sk = sk_next(sk);
	}
get_sk:
2015
	sk_nulls_for_each_from(sk, node) {
2016 2017 2018
		if (!net_eq(sock_net(sk), net))
			continue;
		if (sk->sk_family == st->family) {
L
Linus Torvalds 已提交
2019 2020 2021
			cur = sk;
			goto out;
		}
2022
		icsk = inet_csk(sk);
2023 2024
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
L
Linus Torvalds 已提交
2025 2026 2027 2028 2029 2030 2031
start_req:
			st->uid		= sock_i_uid(sk);
			st->syn_wait_sk = sk;
			st->state	= TCP_SEQ_STATE_OPENREQ;
			st->sbucket	= 0;
			goto get_req;
		}
2032
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2033
	}
2034
	spin_unlock_bh(&ilb->lock);
2035
	st->offset = 0;
2036
	if (++st->bucket < INET_LHTABLE_SIZE) {
2037 2038
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
		spin_lock_bh(&ilb->lock);
2039
		sk = sk_nulls_head(&ilb->head);
L
Linus Torvalds 已提交
2040 2041 2042 2043 2044 2045 2046 2047 2048
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
2049 2050 2051 2052 2053 2054
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	st->offset = 0;
	rc = listening_get_next(seq, NULL);
L
Linus Torvalds 已提交
2055 2056 2057 2058 2059 2060 2061 2062

	while (rc && *pos) {
		rc = listening_get_next(seq, rc);
		--*pos;
	}
	return rc;
}

2063 2064
static inline int empty_bucket(struct tcp_iter_state *st)
{
2065 2066
	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
		hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
2067 2068
}

2069 2070 2071 2072
/*
 * Get first established socket starting from bucket given in st->bucket.
 * If st->bucket is zero, the very first socket in the hash is returned.
 */
L
Linus Torvalds 已提交
2073 2074
static void *established_get_first(struct seq_file *seq)
{
J
Jianjun Kong 已提交
2075
	struct tcp_iter_state *st = seq->private;
2076
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2077 2078
	void *rc = NULL;

2079 2080
	st->offset = 0;
	for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
L
Linus Torvalds 已提交
2081
		struct sock *sk;
2082
		struct hlist_nulls_node *node;
2083
		struct inet_timewait_sock *tw;
2084
		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
L
Linus Torvalds 已提交
2085

2086 2087 2088 2089
		/* Lockless fast path for the common case of empty buckets */
		if (empty_bucket(st))
			continue;

2090
		spin_lock_bh(lock);
2091
		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
2092
			if (sk->sk_family != st->family ||
2093
			    !net_eq(sock_net(sk), net)) {
L
Linus Torvalds 已提交
2094 2095 2096 2097 2098 2099
				continue;
			}
			rc = sk;
			goto out;
		}
		st->state = TCP_SEQ_STATE_TIME_WAIT;
2100
		inet_twsk_for_each(tw, node,
2101
				   &tcp_hashinfo.ehash[st->bucket].twchain) {
2102
			if (tw->tw_family != st->family ||
2103
			    !net_eq(twsk_net(tw), net)) {
L
Linus Torvalds 已提交
2104 2105 2106 2107 2108
				continue;
			}
			rc = tw;
			goto out;
		}
2109
		spin_unlock_bh(lock);
L
Linus Torvalds 已提交
2110 2111 2112 2113 2114 2115 2116 2117 2118
		st->state = TCP_SEQ_STATE_ESTABLISHED;
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
2119
	struct inet_timewait_sock *tw;
2120
	struct hlist_nulls_node *node;
J
Jianjun Kong 已提交
2121
	struct tcp_iter_state *st = seq->private;
2122
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2123 2124

	++st->num;
2125
	++st->offset;
L
Linus Torvalds 已提交
2126 2127 2128 2129 2130

	if (st->state == TCP_SEQ_STATE_TIME_WAIT) {
		tw = cur;
		tw = tw_next(tw);
get_tw:
2131
		while (tw && (tw->tw_family != st->family || !net_eq(twsk_net(tw), net))) {
L
Linus Torvalds 已提交
2132 2133 2134 2135 2136 2137
			tw = tw_next(tw);
		}
		if (tw) {
			cur = tw;
			goto out;
		}
2138
		spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2139 2140
		st->state = TCP_SEQ_STATE_ESTABLISHED;

2141
		/* Look for next non empty bucket */
2142
		st->offset = 0;
2143
		while (++st->bucket <= tcp_hashinfo.ehash_mask &&
2144 2145
				empty_bucket(st))
			;
2146
		if (st->bucket > tcp_hashinfo.ehash_mask)
2147 2148
			return NULL;

2149
		spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
2150
		sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
L
Linus Torvalds 已提交
2151
	} else
2152
		sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
2153

2154
	sk_nulls_for_each_from(sk, node) {
2155
		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
L
Linus Torvalds 已提交
2156 2157 2158 2159
			goto found;
	}

	st->state = TCP_SEQ_STATE_TIME_WAIT;
2160
	tw = tw_head(&tcp_hashinfo.ehash[st->bucket].twchain);
L
Linus Torvalds 已提交
2161 2162 2163 2164 2165 2166 2167 2168 2169
	goto get_tw;
found:
	cur = sk;
out:
	return cur;
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
2170 2171 2172 2173 2174
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	rc = established_get_first(seq);
L
Linus Torvalds 已提交
2175 2176 2177 2178

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
2179
	}
L
Linus Torvalds 已提交
2180 2181 2182 2183 2184 2185
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
J
Jianjun Kong 已提交
2186
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198

	st->state = TCP_SEQ_STATE_LISTENING;
	rc	  = listening_get_idx(seq, &pos);

	if (!rc) {
		st->state = TCP_SEQ_STATE_ESTABLISHED;
		rc	  = established_get_idx(seq, pos);
	}

	return rc;
}

2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233
static void *tcp_seek_last_pos(struct seq_file *seq)
{
	struct tcp_iter_state *st = seq->private;
	int offset = st->offset;
	int orig_num = st->num;
	void *rc = NULL;

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		if (st->bucket >= INET_LHTABLE_SIZE)
			break;
		st->state = TCP_SEQ_STATE_LISTENING;
		rc = listening_get_next(seq, NULL);
		while (offset-- && rc)
			rc = listening_get_next(seq, rc);
		if (rc)
			break;
		st->bucket = 0;
		/* Fallthrough */
	case TCP_SEQ_STATE_ESTABLISHED:
	case TCP_SEQ_STATE_TIME_WAIT:
		st->state = TCP_SEQ_STATE_ESTABLISHED;
		if (st->bucket > tcp_hashinfo.ehash_mask)
			break;
		rc = established_get_first(seq);
		while (offset-- && rc)
			rc = established_get_next(seq, rc);
	}

	st->num = orig_num;

	return rc;
}

L
Linus Torvalds 已提交
2234 2235
static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
J
Jianjun Kong 已提交
2236
	struct tcp_iter_state *st = seq->private;
2237 2238 2239 2240 2241 2242 2243 2244
	void *rc;

	if (*pos && *pos == st->last_pos) {
		rc = tcp_seek_last_pos(seq);
		if (rc)
			goto out;
	}

L
Linus Torvalds 已提交
2245 2246
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
2247 2248 2249 2250 2251 2252 2253
	st->bucket = 0;
	st->offset = 0;
	rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;

out:
	st->last_pos = *pos;
	return rc;
L
Linus Torvalds 已提交
2254 2255 2256 2257
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2258
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271
	void *rc = NULL;

	if (v == SEQ_START_TOKEN) {
		rc = tcp_get_idx(seq, 0);
		goto out;
	}

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		rc = listening_get_next(seq, v);
		if (!rc) {
			st->state = TCP_SEQ_STATE_ESTABLISHED;
2272 2273
			st->bucket = 0;
			st->offset = 0;
L
Linus Torvalds 已提交
2274 2275 2276 2277 2278 2279 2280 2281 2282 2283
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
	case TCP_SEQ_STATE_TIME_WAIT:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
2284
	st->last_pos = *pos;
L
Linus Torvalds 已提交
2285 2286 2287 2288 2289
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2290
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2291 2292 2293 2294

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
		if (v) {
2295 2296
			struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
			read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2297 2298 2299
		}
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2300
			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
L
Linus Torvalds 已提交
2301 2302 2303 2304
		break;
	case TCP_SEQ_STATE_TIME_WAIT:
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2305
			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2306 2307 2308 2309 2310 2311 2312 2313
		break;
	}
}

static int tcp_seq_open(struct inode *inode, struct file *file)
{
	struct tcp_seq_afinfo *afinfo = PDE(inode)->data;
	struct tcp_iter_state *s;
2314
	int err;
L
Linus Torvalds 已提交
2315

2316 2317 2318 2319
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			  sizeof(struct tcp_iter_state));
	if (err < 0)
		return err;
2320

2321
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2322
	s->family		= afinfo->family;
2323
	s->last_pos 		= 0;
2324 2325 2326
	return 0;
}

2327
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2328 2329 2330 2331
{
	int rc = 0;
	struct proc_dir_entry *p;

2332 2333 2334 2335
	afinfo->seq_fops.open		= tcp_seq_open;
	afinfo->seq_fops.read		= seq_read;
	afinfo->seq_fops.llseek		= seq_lseek;
	afinfo->seq_fops.release	= seq_release_net;
2336

2337 2338 2339 2340
	afinfo->seq_ops.start		= tcp_seq_start;
	afinfo->seq_ops.next		= tcp_seq_next;
	afinfo->seq_ops.stop		= tcp_seq_stop;

2341 2342 2343
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
			     &afinfo->seq_fops, afinfo);
	if (!p)
L
Linus Torvalds 已提交
2344 2345 2346
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2347
EXPORT_SYMBOL(tcp_proc_register);
L
Linus Torvalds 已提交
2348

2349
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2350
{
2351
	proc_net_remove(net, afinfo->name);
L
Linus Torvalds 已提交
2352
}
E
Eric Dumazet 已提交
2353
EXPORT_SYMBOL(tcp_proc_unregister);
L
Linus Torvalds 已提交
2354

2355
static void get_openreq4(struct sock *sk, struct request_sock *req,
2356
			 struct seq_file *f, int i, int uid, int *len)
L
Linus Torvalds 已提交
2357
{
2358
	const struct inet_request_sock *ireq = inet_rsk(req);
L
Linus Torvalds 已提交
2359 2360
	int ttd = req->expires - jiffies;

2361 2362
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %p%n",
L
Linus Torvalds 已提交
2363
		i,
2364
		ireq->loc_addr,
E
Eric Dumazet 已提交
2365
		ntohs(inet_sk(sk)->inet_sport),
2366 2367
		ireq->rmt_addr,
		ntohs(ireq->rmt_port),
L
Linus Torvalds 已提交
2368 2369 2370 2371 2372 2373 2374 2375 2376
		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 */
		atomic_read(&sk->sk_refcnt),
2377 2378
		req,
		len);
L
Linus Torvalds 已提交
2379 2380
}

2381
static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
L
Linus Torvalds 已提交
2382 2383 2384
{
	int timer_active;
	unsigned long timer_expires;
2385 2386 2387
	struct tcp_sock *tp = tcp_sk(sk);
	const struct inet_connection_sock *icsk = inet_csk(sk);
	struct inet_sock *inet = inet_sk(sk);
E
Eric Dumazet 已提交
2388 2389 2390 2391
	__be32 dest = inet->inet_daddr;
	__be32 src = inet->inet_rcv_saddr;
	__u16 destp = ntohs(inet->inet_dport);
	__u16 srcp = ntohs(inet->inet_sport);
2392
	int rx_queue;
L
Linus Torvalds 已提交
2393

2394
	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
L
Linus Torvalds 已提交
2395
		timer_active	= 1;
2396 2397
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2398
		timer_active	= 4;
2399
		timer_expires	= icsk->icsk_timeout;
2400
	} else if (timer_pending(&sk->sk_timer)) {
L
Linus Torvalds 已提交
2401
		timer_active	= 2;
2402
		timer_expires	= sk->sk_timer.expires;
L
Linus Torvalds 已提交
2403 2404 2405 2406 2407
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

2408 2409 2410 2411 2412 2413 2414 2415
	if (sk->sk_state == TCP_LISTEN)
		rx_queue = sk->sk_ack_backlog;
	else
		/*
		 * because we dont lock socket, we might find a transient negative value
		 */
		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);

2416
	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2417
			"%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
2418
		i, src, srcp, dest, destp, sk->sk_state,
2419
		tp->write_seq - tp->snd_una,
2420
		rx_queue,
L
Linus Torvalds 已提交
2421 2422
		timer_active,
		jiffies_to_clock_t(timer_expires - jiffies),
2423
		icsk->icsk_retransmits,
2424
		sock_i_uid(sk),
2425
		icsk->icsk_probes_out,
2426 2427
		sock_i_ino(sk),
		atomic_read(&sk->sk_refcnt), sk,
2428 2429
		jiffies_to_clock_t(icsk->icsk_rto),
		jiffies_to_clock_t(icsk->icsk_ack.ato),
2430
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2431
		tp->snd_cwnd,
I
Ilpo Järvinen 已提交
2432
		tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
2433
		len);
L
Linus Torvalds 已提交
2434 2435
}

2436
static void get_timewait4_sock(struct inet_timewait_sock *tw,
2437
			       struct seq_file *f, int i, int *len)
L
Linus Torvalds 已提交
2438
{
2439
	__be32 dest, src;
L
Linus Torvalds 已提交
2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450
	__u16 destp, srcp;
	int ttd = tw->tw_ttd - jiffies;

	if (ttd < 0)
		ttd = 0;

	dest  = tw->tw_daddr;
	src   = tw->tw_rcv_saddr;
	destp = ntohs(tw->tw_dport);
	srcp  = ntohs(tw->tw_sport);

2451 2452
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %p%n",
L
Linus Torvalds 已提交
2453 2454
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
		3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
2455
		atomic_read(&tw->tw_refcnt), tw, len);
L
Linus Torvalds 已提交
2456 2457 2458 2459 2460 2461
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2462
	struct tcp_iter_state *st;
2463
	int len;
L
Linus Torvalds 已提交
2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476

	if (v == SEQ_START_TOKEN) {
		seq_printf(seq, "%-*s\n", TMPSZ - 1,
			   "  sl  local_address rem_address   st tx_queue "
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
			   "inode");
		goto out;
	}
	st = seq->private;

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
	case TCP_SEQ_STATE_ESTABLISHED:
2477
		get_tcp4_sock(v, seq, st->num, &len);
L
Linus Torvalds 已提交
2478 2479
		break;
	case TCP_SEQ_STATE_OPENREQ:
2480
		get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
L
Linus Torvalds 已提交
2481 2482
		break;
	case TCP_SEQ_STATE_TIME_WAIT:
2483
		get_timewait4_sock(v, seq, st->num, &len);
L
Linus Torvalds 已提交
2484 2485
		break;
	}
2486
	seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
L
Linus Torvalds 已提交
2487 2488 2489 2490 2491 2492 2493
out:
	return 0;
}

static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.name		= "tcp",
	.family		= AF_INET,
2494 2495 2496
	.seq_fops	= {
		.owner		= THIS_MODULE,
	},
2497 2498 2499
	.seq_ops	= {
		.show		= tcp4_seq_show,
	},
L
Linus Torvalds 已提交
2500 2501
};

2502
static int __net_init tcp4_proc_init_net(struct net *net)
2503 2504 2505 2506
{
	return tcp_proc_register(net, &tcp4_seq_afinfo);
}

2507
static void __net_exit tcp4_proc_exit_net(struct net *net)
2508 2509 2510 2511 2512 2513 2514 2515 2516
{
	tcp_proc_unregister(net, &tcp4_seq_afinfo);
}

static struct pernet_operations tcp4_net_ops = {
	.init = tcp4_proc_init_net,
	.exit = tcp4_proc_exit_net,
};

L
Linus Torvalds 已提交
2517 2518
int __init tcp4_proc_init(void)
{
2519
	return register_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2520 2521 2522 2523
}

void tcp4_proc_exit(void)
{
2524
	unregister_pernet_subsys(&tcp4_net_ops);
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}
#endif /* CONFIG_PROC_FS */

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struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
{
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	struct iphdr *iph = skb_gro_network_header(skb);
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	switch (skb->ip_summed) {
	case CHECKSUM_COMPLETE:
2534
		if (!tcp_v4_check(skb_gro_len(skb), iph->saddr, iph->daddr,
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				  skb->csum)) {
			skb->ip_summed = CHECKSUM_UNNECESSARY;
			break;
		}

		/* fall through */
	case CHECKSUM_NONE:
		NAPI_GRO_CB(skb)->flush = 1;
		return NULL;
	}

	return tcp_gro_receive(head, skb);
}

int tcp4_gro_complete(struct sk_buff *skb)
{
	struct iphdr *iph = ip_hdr(skb);
	struct tcphdr *th = tcp_hdr(skb);

	th->check = ~tcp_v4_check(skb->len - skb_transport_offset(skb),
				  iph->saddr, iph->daddr, 0);
	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;

	return tcp_gro_complete(skb);
}

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struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2567
	.accept			= inet_csk_accept,
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	.ioctl			= tcp_ioctl,
	.init			= tcp_v4_init_sock,
	.destroy		= tcp_v4_destroy_sock,
	.shutdown		= tcp_shutdown,
	.setsockopt		= tcp_setsockopt,
	.getsockopt		= tcp_getsockopt,
	.recvmsg		= tcp_recvmsg,
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	.sendmsg		= tcp_sendmsg,
	.sendpage		= tcp_sendpage,
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	.backlog_rcv		= tcp_v4_do_rcv,
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	.hash			= inet_hash,
	.unhash			= inet_unhash,
	.get_port		= inet_csk_get_port,
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	.enter_memory_pressure	= tcp_enter_memory_pressure,
	.sockets_allocated	= &tcp_sockets_allocated,
2583
	.orphan_count		= &tcp_orphan_count,
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	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
	.sysctl_mem		= sysctl_tcp_mem,
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2591
	.slab_flags		= SLAB_DESTROY_BY_RCU,
2592
	.twsk_prot		= &tcp_timewait_sock_ops,
2593
	.rsk_prot		= &tcp_request_sock_ops,
2594
	.h.hashinfo		= &tcp_hashinfo,
2595
	.no_autobind		= true,
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#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
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};
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EXPORT_SYMBOL(tcp_prot);
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static int __net_init tcp_sk_init(struct net *net)
{
	return inet_ctl_sock_create(&net->ipv4.tcp_sock,
				    PF_INET, SOCK_RAW, IPPROTO_TCP, net);
}

static void __net_exit tcp_sk_exit(struct net *net)
{
	inet_ctl_sock_destroy(net->ipv4.tcp_sock);
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}

static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
{
	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2618 2619 2620
}

static struct pernet_operations __net_initdata tcp_sk_ops = {
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       .init	   = tcp_sk_init,
       .exit	   = tcp_sk_exit,
       .exit_batch = tcp_sk_exit_batch,
2624 2625
};

2626
void __init tcp_v4_init(void)
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{
2628
	inet_hashinfo_init(&tcp_hashinfo);
2629
	if (register_pernet_subsys(&tcp_sk_ops))
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		panic("Failed to create the TCP control socket.\n");
}