tcp_ipv4.c 60.6 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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#define pr_fmt(fmt) "TCP: " fmt
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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/secure_seq.h>
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#include <net/tcp_memcontrol.h>
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#include <net/busy_poll.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 int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
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			       __be32 daddr, __be32 saddr, const struct tcphdr *th);
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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  __u32 tcp_v4_init_sequence(const 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 &&
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	    (!twp || (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)
{
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	struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
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	struct inet_sock *inet = inet_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
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	__be16 orig_sport, orig_dport;
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	__be32 daddr, nexthop;
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	struct flowi4 *fl4;
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	struct rtable *rt;
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	int err;
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	struct ip_options_rcu *inet_opt;
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	if (addr_len < sizeof(struct sockaddr_in))
		return -EINVAL;

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

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

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	orig_sport = inet->inet_sport;
	orig_dport = usin->sin_port;
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	fl4 = &inet->cork.fl.u.ip4;
	rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
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			      RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			      IPPROTO_TCP,
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			      orig_sport, orig_dport, sk);
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	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		if (err == -ENETUNREACH)
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			IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
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		return err;
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	}
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	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		return -ENETUNREACH;
	}

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	if (!inet_opt || !inet_opt->opt.srr)
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		daddr = fl4->daddr;
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	if (!inet->inet_saddr)
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		inet->inet_saddr = fl4->saddr;
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	sk_rcv_saddr_set(sk, 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;
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		if (likely(!tp->repair))
			tp->write_seq	   = 0;
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	}

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	if (tcp_death_row.sysctl_tw_recycle &&
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	    !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr)
		tcp_fetch_timewait_stamp(sk, &rt->dst);
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	inet->inet_dport = usin->sin_port;
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	sk_daddr_set(sk, daddr);
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	inet_csk(sk)->icsk_ext_hdr_len = 0;
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	if (inet_opt)
		inet_csk(sk)->icsk_ext_hdr_len = inet_opt->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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	sk_set_txhash(sk);
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	rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
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			       inet->inet_sport, inet->inet_dport, sk);
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		rt = NULL;
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		goto failure;
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	}
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	/* 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 && likely(!tp->repair))
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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);
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	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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/*
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 * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191.
 * It can be called through tcp_release_cb() if socket was owned by user
 * at the time tcp_v4_err() was called to handle ICMP message.
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 */
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void tcp_v4_mtu_reduced(struct sock *sk)
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{
	struct dst_entry *dst;
	struct inet_sock *inet = inet_sk(sk);
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	u32 mtu = tcp_sk(sk)->mtu_info;
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	dst = inet_csk_update_pmtu(sk, mtu);
	if (!dst)
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		return;

	/* 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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	    ip_sk_accept_pmtu(sk) &&
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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 */
}
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EXPORT_SYMBOL(tcp_v4_mtu_reduced);
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static void do_redirect(struct sk_buff *skb, struct sock *sk)
{
	struct dst_entry *dst = __sk_dst_check(sk, 0);

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

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/* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */
void tcp_req_err(struct sock *sk, u32 seq)
{
	struct request_sock *req = inet_reqsk(sk);
	struct net *net = sock_net(sk);

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

	if (seq != tcp_rsk(req)->snt_isn) {
		NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
	} else {
		/*
		 * 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(req->rsk_listener, req);
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		NET_INC_STATS_BH(net, LINUX_MIB_LISTENDROPS);
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	}
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	reqsk_put(req);
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}
EXPORT_SYMBOL(tcp_req_err);

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/*
 * 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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	const struct iphdr *iph = (const struct iphdr *)icmp_skb->data;
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	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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	struct request_sock *fastopen;
	__u32 seq, snd_una;
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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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	sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr,
				       th->dest, iph->saddr, ntohs(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;
	}
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	seq = ntohl(th->seq);
	if (sk->sk_state == TCP_NEW_SYN_RECV)
		return tcp_req_err(sk, seq);
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	bh_lock_sock(sk);
	/* If too many ICMPs get dropped on busy
	 * servers this needs to be solved differently.
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	 * We do take care of PMTU discovery (RFC1191) special case :
	 * we can receive locally generated ICMP messages while socket is held.
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	 */
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	if (sock_owned_by_user(sk)) {
		if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
			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);
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	/* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */
	fastopen = tp->fastopen_rsk;
	snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una;
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	if (sk->sk_state != TCP_LISTEN &&
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	    !between(seq, 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) {
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	case ICMP_REDIRECT:
		do_redirect(icmp_skb, sk);
		goto out;
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	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) */
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			/* 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)
				goto out;

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			tp->mtu_info = info;
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			if (!sock_owned_by_user(sk)) {
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				tcp_v4_mtu_reduced(sk);
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			} else {
				if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags))
					sock_hold(sk);
			}
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			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 ||
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		    !icsk->icsk_backoff || fastopen)
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			break;

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		if (sock_owned_by_user(sk))
			break;

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		icsk->icsk_backoff--;
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		icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) :
					       TCP_TIMEOUT_INIT;
		icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
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		skb = tcp_write_queue_head(sk);
		BUG_ON(!skb);

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		remaining = icsk->icsk_rto -
			    min(icsk->icsk_rto,
				tcp_time_stamp - tcp_skb_timestamp(skb));
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		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) {
	case TCP_SYN_SENT:
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	case TCP_SYN_RECV:
		/* Only in fast or simultaneous open. If a fast open socket is
		 * is already accepted it is treated as a connected one below.
		 */
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		if (fastopen && !fastopen->sk)
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			break;

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		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);
}

541
void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
L
Linus Torvalds 已提交
542
{
543
	struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
544

545
	if (skb->ip_summed == CHECKSUM_PARTIAL) {
546
		th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
547
		skb->csum_start = skb_transport_header(skb) - skb->head;
A
Al Viro 已提交
548
		skb->csum_offset = offsetof(struct tcphdr, check);
L
Linus Torvalds 已提交
549
	} else {
550
		th->check = tcp_v4_check(skb->len, saddr, daddr,
551
					 csum_partial(th,
L
Linus Torvalds 已提交
552 553 554 555 556
						      th->doff << 2,
						      skb->csum));
	}
}

557
/* This routine computes an IPv4 TCP checksum. */
558
void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
559
{
560
	const struct inet_sock *inet = inet_sk(sk);
561 562 563

	__tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
}
E
Eric Dumazet 已提交
564
EXPORT_SYMBOL(tcp_v4_send_check);
565

L
Linus Torvalds 已提交
566 567 568 569 570 571 572 573 574 575 576 577 578
/*
 *	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.
 */

579
static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
580
{
581
	const struct tcphdr *th = tcp_hdr(skb);
582 583 584
	struct {
		struct tcphdr th;
#ifdef CONFIG_TCP_MD5SIG
585
		__be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
586 587
#endif
	} rep;
L
Linus Torvalds 已提交
588
	struct ip_reply_arg arg;
589 590
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
591 592 593 594
	const __u8 *hash_location = NULL;
	unsigned char newhash[16];
	int genhash;
	struct sock *sk1 = NULL;
595
#endif
596
	struct net *net;
L
Linus Torvalds 已提交
597 598 599 600 601

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

602 603 604 605
	/* If sk not NULL, it means we did a successful lookup and incoming
	 * route had to be correct. prequeue might have dropped our dst.
	 */
	if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL)
L
Linus Torvalds 已提交
606 607 608
		return;

	/* Swap the send and the receive. */
609 610 611 612 613
	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
614 615

	if (th->ack) {
616
		rep.th.seq = th->ack_seq;
L
Linus Torvalds 已提交
617
	} else {
618 619 620
		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
621 622
	}

623
	memset(&arg, 0, sizeof(arg));
624 625 626
	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);

627
	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
628
#ifdef CONFIG_TCP_MD5SIG
629 630 631 632 633 634 635 636 637
	hash_location = tcp_parse_md5sig_option(th);
	if (!sk && hash_location) {
		/*
		 * active side is lost. Try to find listening socket through
		 * source port, and then find md5 key through listening socket.
		 * we are not loose security here:
		 * Incoming packet is checked with md5 hash with finding key,
		 * no RST generated if md5 hash doesn't match.
		 */
638
		sk1 = __inet_lookup_listener(net,
639 640
					     &tcp_hashinfo, ip_hdr(skb)->saddr,
					     th->source, ip_hdr(skb)->daddr,
641 642 643 644 645 646 647 648 649 650
					     ntohs(th->source), inet_iif(skb));
		/* don't send rst if it can't find key */
		if (!sk1)
			return;
		rcu_read_lock();
		key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
					&ip_hdr(skb)->saddr, AF_INET);
		if (!key)
			goto release_sk1;

651
		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
652 653 654 655 656 657 658 659
		if (genhash || memcmp(hash_location, newhash, 16) != 0)
			goto release_sk1;
	} else {
		key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
					     &ip_hdr(skb)->saddr,
					     AF_INET) : NULL;
	}

660 661 662 663 664 665 666 667 668
	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;

669
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
670 671
				     key, ip_hdr(skb)->saddr,
				     ip_hdr(skb)->daddr, &rep.th);
672 673
	}
#endif
674 675
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
676
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
L
Linus Torvalds 已提交
677
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
678
	arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
679
	/* When socket is gone, all binding information is lost.
A
Alexey Kuznetsov 已提交
680 681
	 * routing might fail in this case. No choice here, if we choose to force
	 * input interface, we will misroute in case of asymmetric route.
682
	 */
A
Alexey Kuznetsov 已提交
683 684
	if (sk)
		arg.bound_dev_if = sk->sk_bound_dev_if;
L
Linus Torvalds 已提交
685

686
	arg.tos = ip_hdr(skb)->tos;
687 688
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
689 690
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
691

692 693
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
694 695 696 697 698 699 700 701

#ifdef CONFIG_TCP_MD5SIG
release_sk1:
	if (sk1) {
		rcu_read_unlock();
		sock_put(sk1);
	}
#endif
L
Linus Torvalds 已提交
702 703 704 705 706 707
}

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

708
static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
709
			    u32 win, u32 tsval, u32 tsecr, int oif,
710
			    struct tcp_md5sig_key *key,
711
			    int reply_flags, u8 tos)
L
Linus Torvalds 已提交
712
{
713
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
714 715
	struct {
		struct tcphdr th;
716
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
717
#ifdef CONFIG_TCP_MD5SIG
718
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
719 720
#endif
			];
L
Linus Torvalds 已提交
721 722
	} rep;
	struct ip_reply_arg arg;
E
Eric Dumazet 已提交
723
	struct net *net = dev_net(skb_dst(skb)->dev);
L
Linus Torvalds 已提交
724 725

	memset(&rep.th, 0, sizeof(struct tcphdr));
726
	memset(&arg, 0, sizeof(arg));
L
Linus Torvalds 已提交
727 728 729

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
730
	if (tsecr) {
731 732 733
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
734 735
		rep.opt[1] = htonl(tsval);
		rep.opt[2] = htonl(tsecr);
736
		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
737 738 739 740 741 742 743 744 745 746 747
	}

	/* 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);

748 749
#ifdef CONFIG_TCP_MD5SIG
	if (key) {
750
		int offset = (tsecr) ? 3 : 0;
751 752 753 754 755 756 757 758

		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;

759
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
760 761
				    key, ip_hdr(skb)->saddr,
				    ip_hdr(skb)->daddr, &rep.th);
762 763
	}
#endif
764
	arg.flags = reply_flags;
765 766
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
L
Linus Torvalds 已提交
767 768
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
769 770
	if (oif)
		arg.bound_dev_if = oif;
771
	arg.tos = tos;
772 773
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
774 775
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
776

777
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
L
Linus Torvalds 已提交
778 779 780 781
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
782
	struct inet_timewait_sock *tw = inet_twsk(sk);
783
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
784

785
	tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
786
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
787
			tcp_time_stamp + tcptw->tw_ts_offset,
788 789
			tcptw->tw_ts_recent,
			tw->tw_bound_dev_if,
790
			tcp_twsk_md5_key(tcptw),
791 792
			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
			tw->tw_tos
793
			);
L
Linus Torvalds 已提交
794

795
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
796 797
}

798
static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
799
				  struct request_sock *req)
L
Linus Torvalds 已提交
800
{
801 802 803 804 805
	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
	 */
	tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
			tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
806
			tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
807
			tcp_time_stamp,
808 809
			req->ts_recent,
			0,
E
Eric Dumazet 已提交
810 811
			tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
					  AF_INET),
812 813
			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
			ip_hdr(skb)->tos);
L
Linus Torvalds 已提交
814 815 816
}

/*
817
 *	Send a SYN-ACK after having received a SYN.
818
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
819 820
 *	socket.
 */
821
static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
822
			      struct flowi *fl,
823
			      struct request_sock *req,
824 825
			      struct tcp_fastopen_cookie *foc,
				  bool attach_req)
L
Linus Torvalds 已提交
826
{
827
	const struct inet_request_sock *ireq = inet_rsk(req);
828
	struct flowi4 fl4;
L
Linus Torvalds 已提交
829
	int err = -1;
830
	struct sk_buff *skb;
L
Linus Torvalds 已提交
831 832

	/* First, grab a route. */
833
	if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
834
		return -1;
L
Linus Torvalds 已提交
835

836
	skb = tcp_make_synack(sk, dst, req, foc, attach_req);
L
Linus Torvalds 已提交
837 838

	if (skb) {
839
		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
L
Linus Torvalds 已提交
840

841 842
		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
					    ireq->ir_rmt_addr,
843
					    ireq->opt);
844
		err = net_xmit_eval(err);
L
Linus Torvalds 已提交
845 846 847 848 849 850
	}

	return err;
}

/*
851
 *	IPv4 request_sock destructor.
L
Linus Torvalds 已提交
852
 */
853
static void tcp_v4_reqsk_destructor(struct request_sock *req)
L
Linus Torvalds 已提交
854
{
J
Jesper Juhl 已提交
855
	kfree(inet_rsk(req)->opt);
L
Linus Torvalds 已提交
856 857 858
}


859 860 861 862 863 864 865 866
#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.  */
867
struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
E
Eric Dumazet 已提交
868 869
					 const union tcp_md5_addr *addr,
					 int family)
870
{
871
	const struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
872 873
	struct tcp_md5sig_key *key;
	unsigned int size = sizeof(struct in_addr);
874
	const struct tcp_md5sig_info *md5sig;
875

876 877
	/* caller either holds rcu_read_lock() or socket lock */
	md5sig = rcu_dereference_check(tp->md5sig_info,
878
				       sock_owned_by_user(sk) ||
879
				       lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
880
	if (!md5sig)
881
		return NULL;
E
Eric Dumazet 已提交
882 883 884 885
#if IS_ENABLED(CONFIG_IPV6)
	if (family == AF_INET6)
		size = sizeof(struct in6_addr);
#endif
886
	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
E
Eric Dumazet 已提交
887 888 889 890
		if (key->family != family)
			continue;
		if (!memcmp(&key->addr, addr, size))
			return key;
891 892 893
	}
	return NULL;
}
E
Eric Dumazet 已提交
894
EXPORT_SYMBOL(tcp_md5_do_lookup);
895

896
struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
897
					 const struct sock *addr_sk)
898
{
899
	const union tcp_md5_addr *addr;
E
Eric Dumazet 已提交
900

901
	addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
E
Eric Dumazet 已提交
902
	return tcp_md5_do_lookup(sk, addr, AF_INET);
903 904 905 906
}
EXPORT_SYMBOL(tcp_v4_md5_lookup);

/* This can be called on a newly created socket, from other files */
E
Eric Dumazet 已提交
907 908
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
909 910
{
	/* Add Key to the list */
911
	struct tcp_md5sig_key *key;
912
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
913
	struct tcp_md5sig_info *md5sig;
914

915
	key = tcp_md5_do_lookup(sk, addr, family);
916 917
	if (key) {
		/* Pre-existing entry - just update that one. */
E
Eric Dumazet 已提交
918
		memcpy(key->key, newkey, newkeylen);
919
		key->keylen = newkeylen;
E
Eric Dumazet 已提交
920 921
		return 0;
	}
922

923 924
	md5sig = rcu_dereference_protected(tp->md5sig_info,
					   sock_owned_by_user(sk));
E
Eric Dumazet 已提交
925 926 927
	if (!md5sig) {
		md5sig = kmalloc(sizeof(*md5sig), gfp);
		if (!md5sig)
928 929
			return -ENOMEM;

E
Eric Dumazet 已提交
930 931
		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
		INIT_HLIST_HEAD(&md5sig->head);
932
		rcu_assign_pointer(tp->md5sig_info, md5sig);
E
Eric Dumazet 已提交
933
	}
934

935
	key = sock_kmalloc(sk, sizeof(*key), gfp);
E
Eric Dumazet 已提交
936 937
	if (!key)
		return -ENOMEM;
938
	if (!tcp_alloc_md5sig_pool()) {
939
		sock_kfree_s(sk, key, sizeof(*key));
E
Eric Dumazet 已提交
940
		return -ENOMEM;
941
	}
E
Eric Dumazet 已提交
942 943 944 945 946 947 948 949

	memcpy(key->key, newkey, newkeylen);
	key->keylen = newkeylen;
	key->family = family;
	memcpy(&key->addr, addr,
	       (family == AF_INET6) ? sizeof(struct in6_addr) :
				      sizeof(struct in_addr));
	hlist_add_head_rcu(&key->node, &md5sig->head);
950 951
	return 0;
}
E
Eric Dumazet 已提交
952
EXPORT_SYMBOL(tcp_md5_do_add);
953

E
Eric Dumazet 已提交
954
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
955
{
E
Eric Dumazet 已提交
956 957
	struct tcp_md5sig_key *key;

958
	key = tcp_md5_do_lookup(sk, addr, family);
E
Eric Dumazet 已提交
959 960 961
	if (!key)
		return -ENOENT;
	hlist_del_rcu(&key->node);
962
	atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
963 964
	kfree_rcu(key, rcu);
	return 0;
965
}
E
Eric Dumazet 已提交
966
EXPORT_SYMBOL(tcp_md5_do_del);
967

968
static void tcp_clear_md5_list(struct sock *sk)
969 970
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
971
	struct tcp_md5sig_key *key;
972
	struct hlist_node *n;
973
	struct tcp_md5sig_info *md5sig;
974

975 976
	md5sig = rcu_dereference_protected(tp->md5sig_info, 1);

977
	hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
E
Eric Dumazet 已提交
978
		hlist_del_rcu(&key->node);
979
		atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
980
		kfree_rcu(key, rcu);
981 982 983
	}
}

984 985
static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
				 int optlen)
986 987 988 989 990 991 992
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;

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

993
	if (copy_from_user(&cmd, optval, sizeof(cmd)))
994 995 996 997 998
		return -EFAULT;

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

999
	if (!cmd.tcpm_keylen)
E
Eric Dumazet 已提交
1000 1001
		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
				      AF_INET);
1002 1003 1004 1005

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

E
Eric Dumazet 已提交
1006 1007 1008
	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
			      AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
			      GFP_KERNEL);
1009 1010
}

1011 1012
static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
					__be32 daddr, __be32 saddr, int nbytes)
1013 1014
{
	struct tcp4_pseudohdr *bp;
1015
	struct scatterlist sg;
1016 1017 1018 1019

	bp = &hp->md5_blk.ip4;

	/*
1020
	 * 1. the TCP pseudo-header (in the order: source IP address,
1021 1022 1023 1024 1025 1026
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
1027
	bp->protocol = IPPROTO_TCP;
1028
	bp->len = cpu_to_be16(nbytes);
1029

1030 1031 1032 1033
	sg_init_one(&sg, bp, sizeof(*bp));
	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
}

E
Eric Dumazet 已提交
1034
static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1035
			       __be32 daddr, __be32 saddr, const struct tcphdr *th)
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053
{
	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))
1054 1055 1056 1057
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;
1058

1059 1060 1061 1062
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
1063
	return 1;
1064 1065
}

1066 1067
int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
			const struct sock *sk,
E
Eric Dumazet 已提交
1068
			const struct sk_buff *skb)
1069
{
1070 1071
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
E
Eric Dumazet 已提交
1072
	const struct tcphdr *th = tcp_hdr(skb);
1073 1074
	__be32 saddr, daddr;

1075 1076 1077
	if (sk) { /* valid for establish/request sockets */
		saddr = sk->sk_rcv_saddr;
		daddr = sk->sk_daddr;
1078
	} else {
1079 1080 1081
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
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

	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;
1111
}
1112
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1113

1114 1115
#endif

1116
/* Called with rcu_read_lock() */
1117
static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1118
				    const struct sk_buff *skb)
1119
{
1120
#ifdef CONFIG_TCP_MD5SIG
1121 1122 1123 1124 1125 1126 1127 1128
	/*
	 * 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.
	 */
1129
	const __u8 *hash_location = NULL;
1130
	struct tcp_md5sig_key *hash_expected;
1131
	const struct iphdr *iph = ip_hdr(skb);
1132
	const struct tcphdr *th = tcp_hdr(skb);
1133 1134 1135
	int genhash;
	unsigned char newhash[16];

E
Eric Dumazet 已提交
1136 1137
	hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
					  AF_INET);
1138
	hash_location = tcp_parse_md5sig_option(th);
1139 1140 1141

	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
E
Eric Dumazet 已提交
1142
		return false;
1143 1144

	if (hash_expected && !hash_location) {
1145
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
E
Eric Dumazet 已提交
1146
		return true;
1147 1148 1149
	}

	if (!hash_expected && hash_location) {
1150
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
E
Eric Dumazet 已提交
1151
		return true;
1152 1153 1154 1155 1156
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
1157 1158
	genhash = tcp_v4_md5_hash_skb(newhash,
				      hash_expected,
1159
				      NULL, skb);
1160 1161

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1162 1163 1164 1165 1166
		net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n",
				     &iph->saddr, ntohs(th->source),
				     &iph->daddr, ntohs(th->dest),
				     genhash ? " tcp_v4_calc_md5_hash failed"
				     : "");
E
Eric Dumazet 已提交
1167
		return true;
1168
	}
E
Eric Dumazet 已提交
1169
	return false;
1170
#endif
1171 1172
	return false;
}
1173

1174 1175
static void tcp_v4_init_req(struct request_sock *req,
			    const struct sock *sk_listener,
1176 1177 1178 1179
			    struct sk_buff *skb)
{
	struct inet_request_sock *ireq = inet_rsk(req);

1180 1181 1182
	sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr);
	sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
	ireq->no_srccheck = inet_sk(sk_listener)->transparent;
1183 1184 1185
	ireq->opt = tcp_v4_save_options(skb);
}

1186 1187
static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
					  struct flowi *fl,
1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
					  const struct request_sock *req,
					  bool *strict)
{
	struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);

	if (strict) {
		if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
			*strict = true;
		else
			*strict = false;
	}

	return dst;
}

1203
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1204
	.family		=	PF_INET,
1205
	.obj_size	=	sizeof(struct tcp_request_sock),
1206
	.rtx_syn_ack	=	tcp_rtx_synack,
1207 1208
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1209
	.send_reset	=	tcp_v4_send_reset,
S
stephen hemminger 已提交
1210
	.syn_ack_timeout =	tcp_syn_ack_timeout,
L
Linus Torvalds 已提交
1211 1212
};

1213
static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1214
	.mss_clamp	=	TCP_MSS_DEFAULT,
1215
#ifdef CONFIG_TCP_MD5SIG
1216
	.req_md5_lookup	=	tcp_v4_md5_lookup,
1217
	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1218
#endif
1219
	.init_req	=	tcp_v4_init_req,
1220 1221 1222
#ifdef CONFIG_SYN_COOKIES
	.cookie_init_seq =	cookie_v4_init_sequence,
#endif
1223
	.route_req	=	tcp_v4_route_req,
1224
	.init_seq	=	tcp_v4_init_sequence,
1225
	.send_synack	=	tcp_v4_send_synack,
1226
};
1227

L
Linus Torvalds 已提交
1228 1229 1230
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
	/* Never answer to SYNs send to broadcast or multicast */
E
Eric Dumazet 已提交
1231
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
L
Linus Torvalds 已提交
1232 1233
		goto drop;

O
Octavian Purdila 已提交
1234 1235
	return tcp_conn_request(&tcp_request_sock_ops,
				&tcp_request_sock_ipv4_ops, sk, skb);
L
Linus Torvalds 已提交
1236 1237

drop:
1238
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1239 1240
	return 0;
}
E
Eric Dumazet 已提交
1241
EXPORT_SYMBOL(tcp_v4_conn_request);
L
Linus Torvalds 已提交
1242 1243 1244 1245 1246 1247


/*
 * The three way handshake has completed - we got a valid synack -
 * now create the new socket.
 */
1248
struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1249
				  struct request_sock *req,
1250 1251 1252
				  struct dst_entry *dst,
				  struct request_sock *req_unhash,
				  bool *own_req)
L
Linus Torvalds 已提交
1253
{
1254
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1255 1256 1257
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1258 1259 1260
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
1261
	struct ip_options_rcu *inet_opt;
L
Linus Torvalds 已提交
1262 1263 1264 1265 1266 1267

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
1268
		goto exit_nonewsk;
L
Linus Torvalds 已提交
1269

1270
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1271
	inet_sk_rx_dst_set(newsk, skb);
L
Linus Torvalds 已提交
1272 1273 1274

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1275
	ireq		      = inet_rsk(req);
1276 1277
	sk_daddr_set(newsk, ireq->ir_rmt_addr);
	sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1278
	newinet->inet_saddr	      = ireq->ir_loc_addr;
1279 1280
	inet_opt	      = ireq->opt;
	rcu_assign_pointer(newinet->inet_opt, inet_opt);
1281
	ireq->opt	      = NULL;
1282
	newinet->mc_index     = inet_iif(skb);
1283
	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
1284
	newinet->rcv_tos      = ip_hdr(skb)->tos;
1285
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1286 1287
	if (inet_opt)
		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
E
Eric Dumazet 已提交
1288
	newinet->inet_id = newtp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
1289

E
Eric Dumazet 已提交
1290 1291 1292 1293 1294 1295 1296
	if (!dst) {
		dst = inet_csk_route_child_sock(sk, newsk, req);
		if (!dst)
			goto put_and_exit;
	} else {
		/* syncookie case : see end of cookie_v4_check() */
	}
1297 1298
	sk_setup_caps(newsk, dst);

1299 1300
	tcp_ca_openreq_child(newsk, dst);

L
Linus Torvalds 已提交
1301
	tcp_sync_mss(newsk, dst_mtu(dst));
1302
	newtp->advmss = dst_metric_advmss(dst);
1303 1304 1305 1306
	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
1307 1308
	tcp_initialize_rcv_mss(newsk);

1309 1310
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
E
Eric Dumazet 已提交
1311 1312
	key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
				AF_INET);
1313
	if (key) {
1314 1315 1316 1317 1318 1319
		/*
		 * 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.
		 */
E
Eric Dumazet 已提交
1320 1321
		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
			       AF_INET, key->key, key->keylen, GFP_ATOMIC);
E
Eric Dumazet 已提交
1322
		sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1323 1324 1325
	}
#endif

1326 1327
	if (__inet_inherit_port(sk, newsk) < 0)
		goto put_and_exit;
1328
	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
E
Eric Dumazet 已提交
1329
	if (*own_req)
1330
		tcp_move_syn(newtp, req);
L
Linus Torvalds 已提交
1331 1332 1333 1334

	return newsk;

exit_overflow:
1335
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1336 1337
exit_nonewsk:
	dst_release(dst);
L
Linus Torvalds 已提交
1338
exit:
1339
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1340
	return NULL;
1341
put_and_exit:
1342 1343
	inet_csk_prepare_forced_close(newsk);
	tcp_done(newsk);
1344
	goto exit;
L
Linus Torvalds 已提交
1345
}
E
Eric Dumazet 已提交
1346
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
L
Linus Torvalds 已提交
1347

1348
static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
1349
{
1350
#ifdef CONFIG_SYN_COOKIES
1351
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1352

1353
	if (!th->syn)
C
Cong Wang 已提交
1354
		sk = cookie_v4_check(sk, skb);
L
Linus Torvalds 已提交
1355 1356 1357 1358 1359
#endif
	return sk;
}

/* The socket must have it's spinlock held when we get
1360
 * here, unless it is a TCP_LISTEN socket.
L
Linus Torvalds 已提交
1361 1362 1363 1364 1365 1366 1367 1368
 *
 * 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)
{
1369 1370
	struct sock *rsk;

L
Linus Torvalds 已提交
1371
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1372 1373
		struct dst_entry *dst = sk->sk_rx_dst;

1374
		sock_rps_save_rxhash(sk, skb);
1375
		sk_mark_napi_id(sk, skb);
1376
		if (dst) {
E
Eric Dumazet 已提交
1377
			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1378
			    !dst->ops->check(dst, 0)) {
1379 1380 1381 1382
				dst_release(dst);
				sk->sk_rx_dst = NULL;
			}
		}
1383
		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
L
Linus Torvalds 已提交
1384 1385 1386
		return 0;
	}

E
Eric Dumazet 已提交
1387
	if (tcp_checksum_complete(skb))
L
Linus Torvalds 已提交
1388 1389 1390
		goto csum_err;

	if (sk->sk_state == TCP_LISTEN) {
1391 1392
		struct sock *nsk = tcp_v4_cookie_check(sk, skb);

L
Linus Torvalds 已提交
1393 1394 1395
		if (!nsk)
			goto discard;
		if (nsk != sk) {
1396
			sock_rps_save_rxhash(nsk, skb);
1397
			sk_mark_napi_id(nsk, skb);
1398 1399
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1400
				goto reset;
1401
			}
L
Linus Torvalds 已提交
1402 1403
			return 0;
		}
1404
	} else
1405
		sock_rps_save_rxhash(sk, skb);
1406

1407
	if (tcp_rcv_state_process(sk, skb)) {
1408
		rsk = sk;
L
Linus Torvalds 已提交
1409
		goto reset;
1410
	}
L
Linus Torvalds 已提交
1411 1412 1413
	return 0;

reset:
1414
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1415 1416 1417 1418 1419 1420 1421 1422 1423 1424
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:
1425
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1426
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1427 1428
	goto discard;
}
E
Eric Dumazet 已提交
1429
EXPORT_SYMBOL(tcp_v4_do_rcv);
L
Linus Torvalds 已提交
1430

1431
void tcp_v4_early_demux(struct sk_buff *skb)
D
David S. Miller 已提交
1432 1433 1434 1435 1436 1437
{
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct sock *sk;

	if (skb->pkt_type != PACKET_HOST)
1438
		return;
D
David S. Miller 已提交
1439

1440
	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1441
		return;
D
David S. Miller 已提交
1442 1443

	iph = ip_hdr(skb);
1444
	th = tcp_hdr(skb);
D
David S. Miller 已提交
1445 1446

	if (th->doff < sizeof(struct tcphdr) / 4)
1447
		return;
D
David S. Miller 已提交
1448

1449
	sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
D
David S. Miller 已提交
1450
				       iph->saddr, th->source,
1451
				       iph->daddr, ntohs(th->dest),
E
Eric Dumazet 已提交
1452
				       skb->skb_iif);
D
David S. Miller 已提交
1453 1454 1455
	if (sk) {
		skb->sk = sk;
		skb->destructor = sock_edemux;
1456
		if (sk_fullsock(sk)) {
1457
			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
E
Eric Dumazet 已提交
1458

D
David S. Miller 已提交
1459 1460
			if (dst)
				dst = dst_check(dst, 0);
1461
			if (dst &&
E
Eric Dumazet 已提交
1462
			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1463
				skb_dst_set_noref(skb, dst);
D
David S. Miller 已提交
1464 1465 1466 1467
		}
	}
}

E
Eric Dumazet 已提交
1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
/* Packet is added to VJ-style prequeue for processing in process
 * context, if a reader task is waiting. Apparently, this exciting
 * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93)
 * failed somewhere. Latency? Burstiness? Well, at least now we will
 * see, why it failed. 8)8)				  --ANK
 *
 */
bool tcp_prequeue(struct sock *sk, struct sk_buff *skb)
{
	struct tcp_sock *tp = tcp_sk(sk);

	if (sysctl_tcp_low_latency || !tp->ucopy.task)
		return false;

	if (skb->len <= tcp_hdrlen(skb) &&
	    skb_queue_len(&tp->ucopy.prequeue) == 0)
		return false;

1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496
	/* Before escaping RCU protected region, we need to take care of skb
	 * dst. Prequeue is only enabled for established sockets.
	 * For such sockets, we might need the skb dst only to set sk->sk_rx_dst
	 * Instead of doing full sk_rx_dst validity here, let's perform
	 * an optimistic check.
	 */
	if (likely(sk->sk_rx_dst))
		skb_dst_drop(skb);
	else
		skb_dst_force(skb);

E
Eric Dumazet 已提交
1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522
	__skb_queue_tail(&tp->ucopy.prequeue, skb);
	tp->ucopy.memory += skb->truesize;
	if (tp->ucopy.memory > sk->sk_rcvbuf) {
		struct sk_buff *skb1;

		BUG_ON(sock_owned_by_user(sk));

		while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) {
			sk_backlog_rcv(sk, skb1);
			NET_INC_STATS_BH(sock_net(sk),
					 LINUX_MIB_TCPPREQUEUEDROPPED);
		}

		tp->ucopy.memory = 0;
	} else if (skb_queue_len(&tp->ucopy.prequeue) == 1) {
		wake_up_interruptible_sync_poll(sk_sleep(sk),
					   POLLIN | POLLRDNORM | POLLRDBAND);
		if (!inet_csk_ack_scheduled(sk))
			inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK,
						  (3 * tcp_rto_min(sk)) / 4,
						  TCP_RTO_MAX);
	}
	return true;
}
EXPORT_SYMBOL(tcp_prequeue);

L
Linus Torvalds 已提交
1523 1524 1525 1526 1527 1528
/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
1529
	const struct iphdr *iph;
1530
	const struct tcphdr *th;
L
Linus Torvalds 已提交
1531 1532
	struct sock *sk;
	int ret;
1533
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
1534 1535 1536 1537 1538

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

	/* Count it even if it's bad */
1539
	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
L
Linus Torvalds 已提交
1540 1541 1542 1543

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

1544
	th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1545 1546 1547 1548 1549 1550 1551 1552

	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
1553
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1554
	 * So, we defer the checks. */
1555 1556

	if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1557
		goto csum_error;
L
Linus Torvalds 已提交
1558

1559
	th = tcp_hdr(skb);
1560
	iph = ip_hdr(skb);
1561 1562 1563 1564 1565 1566 1567
	/* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
	 * barrier() makes sure compiler wont play fool^Waliasing games.
	 */
	memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
		sizeof(struct inet_skb_parm));
	barrier();

L
Linus Torvalds 已提交
1568 1569 1570 1571
	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);
1572
	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1573
	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1574
	TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
L
Linus Torvalds 已提交
1575 1576
	TCP_SKB_CB(skb)->sacked	 = 0;

1577
lookup:
1578
	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
L
Linus Torvalds 已提交
1579 1580 1581
	if (!sk)
		goto no_tcp_socket;

E
Eric Dumazet 已提交
1582 1583 1584 1585
process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

1586 1587 1588 1589 1590 1591 1592
	if (sk->sk_state == TCP_NEW_SYN_RECV) {
		struct request_sock *req = inet_reqsk(sk);
		struct sock *nsk = NULL;

		sk = req->rsk_listener;
		if (tcp_v4_inbound_md5_hash(sk, skb))
			goto discard_and_relse;
1593
		if (likely(sk->sk_state == TCP_LISTEN)) {
1594
			nsk = tcp_check_req(sk, skb, req, false);
1595
		} else {
1596
			inet_csk_reqsk_queue_drop_and_put(sk, req);
1597 1598
			goto lookup;
		}
1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612
		if (!nsk) {
			reqsk_put(req);
			goto discard_it;
		}
		if (nsk == sk) {
			sock_hold(sk);
			reqsk_put(req);
		} else if (tcp_child_process(sk, nsk, skb)) {
			tcp_v4_send_reset(nsk, skb);
			goto discard_it;
		} else {
			return 0;
		}
	}
1613 1614
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1615
		goto discard_and_relse;
1616
	}
1617

L
Linus Torvalds 已提交
1618 1619
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1620 1621 1622 1623

	if (tcp_v4_inbound_md5_hash(sk, skb))
		goto discard_and_relse;

1624
	nf_reset(skb);
L
Linus Torvalds 已提交
1625

1626
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1627 1628 1629 1630
		goto discard_and_relse;

	skb->dev = NULL;

1631 1632 1633 1634 1635 1636 1637
	if (sk->sk_state == TCP_LISTEN) {
		ret = tcp_v4_do_rcv(sk, skb);
		goto put_and_return;
	}

	sk_incoming_cpu_update(sk);

1638
	bh_lock_sock_nested(sk);
1639
	tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
L
Linus Torvalds 已提交
1640 1641
	ret = 0;
	if (!sock_owned_by_user(sk)) {
D
Dan Williams 已提交
1642
		if (!tcp_prequeue(sk, skb))
L
Linus Torvalds 已提交
1643
			ret = tcp_v4_do_rcv(sk, skb);
1644 1645
	} else if (unlikely(sk_add_backlog(sk, skb,
					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
Z
Zhu Yi 已提交
1646
		bh_unlock_sock(sk);
1647
		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
Z
Zhu Yi 已提交
1648 1649
		goto discard_and_relse;
	}
L
Linus Torvalds 已提交
1650 1651
	bh_unlock_sock(sk);

1652
put_and_return:
L
Linus Torvalds 已提交
1653 1654 1655 1656 1657 1658 1659 1660
	sock_put(sk);

	return ret;

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

E
Eric Dumazet 已提交
1661
	if (tcp_checksum_complete(skb)) {
1662 1663
csum_error:
		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
L
Linus Torvalds 已提交
1664
bad_packet:
1665
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1666
	} else {
1667
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1668 1669 1670 1671 1672
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
1673
	return 0;
L
Linus Torvalds 已提交
1674 1675 1676 1677 1678 1679 1680

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1681
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1682 1683 1684
		goto discard_it;
	}

1685 1686 1687
	if (tcp_checksum_complete(skb)) {
		inet_twsk_put(inet_twsk(sk));
		goto csum_error;
L
Linus Torvalds 已提交
1688
	}
1689
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1690
	case TCP_TW_SYN: {
1691
		struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1692
							&tcp_hashinfo,
1693
							iph->saddr, th->source,
1694
							iph->daddr, th->dest,
1695
							inet_iif(skb));
L
Linus Torvalds 已提交
1696
		if (sk2) {
1697
			inet_twsk_deschedule_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712
			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;
}

1713 1714 1715 1716 1717
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,
};
L
Linus Torvalds 已提交
1718

1719
void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
E
Eric Dumazet 已提交
1720 1721 1722
{
	struct dst_entry *dst = skb_dst(skb);

1723 1724 1725 1726 1727
	if (dst) {
		dst_hold(dst);
		sk->sk_rx_dst = dst;
		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
	}
E
Eric Dumazet 已提交
1728
}
1729
EXPORT_SYMBOL(inet_sk_rx_dst_set);
E
Eric Dumazet 已提交
1730

1731
const struct inet_connection_sock_af_ops ipv4_specific = {
1732 1733 1734
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
E
Eric Dumazet 已提交
1735
	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1736 1737 1738 1739 1740 1741 1742
	.conn_request	   = tcp_v4_conn_request,
	.syn_recv_sock	   = tcp_v4_syn_recv_sock,
	.net_header_len	   = sizeof(struct iphdr),
	.setsockopt	   = ip_setsockopt,
	.getsockopt	   = ip_getsockopt,
	.addr2sockaddr	   = inet_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in),
1743
	.bind_conflict	   = inet_csk_bind_conflict,
1744
#ifdef CONFIG_COMPAT
1745 1746
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1747
#endif
1748
	.mtu_reduced	   = tcp_v4_mtu_reduced,
L
Linus Torvalds 已提交
1749
};
E
Eric Dumazet 已提交
1750
EXPORT_SYMBOL(ipv4_specific);
L
Linus Torvalds 已提交
1751

1752
#ifdef CONFIG_TCP_MD5SIG
1753
static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1754
	.md5_lookup		= tcp_v4_md5_lookup,
1755
	.calc_md5_hash		= tcp_v4_md5_hash_skb,
1756 1757
	.md5_parse		= tcp_v4_parse_md5_keys,
};
1758
#endif
1759

L
Linus Torvalds 已提交
1760 1761 1762 1763 1764
/* 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)
{
1765
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1766

1767
	tcp_init_sock(sk);
L
Linus Torvalds 已提交
1768

1769
	icsk->icsk_af_ops = &ipv4_specific;
1770

1771
#ifdef CONFIG_TCP_MD5SIG
1772
	tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1773
#endif
L
Linus Torvalds 已提交
1774 1775 1776 1777

	return 0;
}

1778
void tcp_v4_destroy_sock(struct sock *sk)
L
Linus Torvalds 已提交
1779 1780 1781 1782 1783
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1784
	tcp_cleanup_congestion_control(sk);
1785

L
Linus Torvalds 已提交
1786
	/* Cleanup up the write buffer. */
1787
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
1788 1789

	/* Cleans up our, hopefully empty, out_of_order_queue. */
1790
	__skb_queue_purge(&tp->out_of_order_queue);
L
Linus Torvalds 已提交
1791

1792 1793 1794
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
E
Eric Dumazet 已提交
1795
		tcp_clear_md5_list(sk);
1796
		kfree_rcu(tp->md5sig_info, rcu);
1797 1798 1799
		tp->md5sig_info = NULL;
	}
#endif
C
Chris Leech 已提交
1800

L
Linus Torvalds 已提交
1801 1802 1803 1804
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1805
	if (inet_csk(sk)->icsk_bind_hash)
1806
		inet_put_port(sk);
L
Linus Torvalds 已提交
1807

1808
	BUG_ON(tp->fastopen_rsk);
1809

1810 1811
	/* If socket is aborted during connect operation */
	tcp_free_fastopen_req(tp);
1812
	tcp_saved_syn_free(tp);
1813

1814
	sk_sockets_allocated_dec(sk);
G
Glauber Costa 已提交
1815
	sock_release_memcg(sk);
L
Linus Torvalds 已提交
1816 1817 1818 1819 1820 1821
}
EXPORT_SYMBOL(tcp_v4_destroy_sock);

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

1822 1823 1824 1825 1826
/*
 * 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
1827 1828
static void *listening_get_next(struct seq_file *seq, void *cur)
{
1829
	struct inet_connection_sock *icsk;
1830
	struct hlist_nulls_node *node;
L
Linus Torvalds 已提交
1831
	struct sock *sk = cur;
1832
	struct inet_listen_hashbucket *ilb;
J
Jianjun Kong 已提交
1833
	struct tcp_iter_state *st = seq->private;
1834
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1835 1836

	if (!sk) {
1837
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
1838
		spin_lock_bh(&ilb->lock);
1839
		sk = sk_nulls_head(&ilb->head);
1840
		st->offset = 0;
L
Linus Torvalds 已提交
1841 1842
		goto get_sk;
	}
1843
	ilb = &tcp_hashinfo.listening_hash[st->bucket];
L
Linus Torvalds 已提交
1844
	++st->num;
1845
	++st->offset;
L
Linus Torvalds 已提交
1846

1847
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1848
get_sk:
1849
	sk_nulls_for_each_from(sk, node) {
1850 1851 1852
		if (!net_eq(sock_net(sk), net))
			continue;
		if (sk->sk_family == st->family) {
L
Linus Torvalds 已提交
1853 1854 1855
			cur = sk;
			goto out;
		}
1856
		icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1857
	}
1858
	spin_unlock_bh(&ilb->lock);
1859
	st->offset = 0;
1860
	if (++st->bucket < INET_LHTABLE_SIZE) {
1861 1862
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
		spin_lock_bh(&ilb->lock);
1863
		sk = sk_nulls_head(&ilb->head);
L
Linus Torvalds 已提交
1864 1865 1866 1867 1868 1869 1870 1871 1872
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
1873 1874 1875 1876 1877 1878
	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
1879 1880 1881 1882 1883 1884 1885 1886

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

E
Eric Dumazet 已提交
1887
static inline bool empty_bucket(const struct tcp_iter_state *st)
1888
{
E
Eric Dumazet 已提交
1889
	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1890 1891
}

1892 1893 1894 1895
/*
 * 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
1896 1897
static void *established_get_first(struct seq_file *seq)
{
J
Jianjun Kong 已提交
1898
	struct tcp_iter_state *st = seq->private;
1899
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1900 1901
	void *rc = NULL;

1902 1903
	st->offset = 0;
	for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
L
Linus Torvalds 已提交
1904
		struct sock *sk;
1905
		struct hlist_nulls_node *node;
1906
		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
L
Linus Torvalds 已提交
1907

1908 1909 1910 1911
		/* Lockless fast path for the common case of empty buckets */
		if (empty_bucket(st))
			continue;

1912
		spin_lock_bh(lock);
1913
		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1914
			if (sk->sk_family != st->family ||
1915
			    !net_eq(sock_net(sk), net)) {
L
Linus Torvalds 已提交
1916 1917 1918 1919 1920
				continue;
			}
			rc = sk;
			goto out;
		}
1921
		spin_unlock_bh(lock);
L
Linus Torvalds 已提交
1922 1923 1924 1925 1926 1927 1928 1929
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
1930
	struct hlist_nulls_node *node;
J
Jianjun Kong 已提交
1931
	struct tcp_iter_state *st = seq->private;
1932
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1933 1934

	++st->num;
1935
	++st->offset;
L
Linus Torvalds 已提交
1936

E
Eric Dumazet 已提交
1937
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1938

1939
	sk_nulls_for_each_from(sk, node) {
1940
		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
E
Eric Dumazet 已提交
1941
			return sk;
L
Linus Torvalds 已提交
1942 1943
	}

E
Eric Dumazet 已提交
1944 1945 1946
	spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
	++st->bucket;
	return established_get_first(seq);
L
Linus Torvalds 已提交
1947 1948 1949 1950
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
1951 1952 1953 1954 1955
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	rc = established_get_first(seq);
L
Linus Torvalds 已提交
1956 1957 1958 1959

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
1960
	}
L
Linus Torvalds 已提交
1961 1962 1963 1964 1965 1966
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
J
Jianjun Kong 已提交
1967
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979

	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;
}

1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997
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_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;
E
Eric Dumazet 已提交
1998
		st->state = TCP_SEQ_STATE_ESTABLISHED;
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
		/* Fallthrough */
	case 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
2013 2014
static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
J
Jianjun Kong 已提交
2015
	struct tcp_iter_state *st = seq->private;
2016 2017 2018 2019 2020 2021 2022 2023
	void *rc;

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

L
Linus Torvalds 已提交
2024 2025
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
2026 2027 2028 2029 2030 2031 2032
	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
2033 2034 2035 2036
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2037
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049
	void *rc = NULL;

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

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
		rc = listening_get_next(seq, v);
		if (!rc) {
			st->state = TCP_SEQ_STATE_ESTABLISHED;
2050 2051
			st->bucket = 0;
			st->offset = 0;
L
Linus Torvalds 已提交
2052 2053 2054 2055 2056 2057 2058 2059 2060
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
2061
	st->last_pos = *pos;
L
Linus Torvalds 已提交
2062 2063 2064 2065 2066
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2067
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2068 2069 2070 2071

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2072
			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
L
Linus Torvalds 已提交
2073 2074 2075
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2076
			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2077 2078 2079 2080
		break;
	}
}

2081
int tcp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2082
{
A
Al Viro 已提交
2083
	struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
L
Linus Torvalds 已提交
2084
	struct tcp_iter_state *s;
2085
	int err;
L
Linus Torvalds 已提交
2086

2087 2088 2089 2090
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			  sizeof(struct tcp_iter_state));
	if (err < 0)
		return err;
2091

2092
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2093
	s->family		= afinfo->family;
S
stephen hemminger 已提交
2094
	s->last_pos		= 0;
2095 2096
	return 0;
}
2097
EXPORT_SYMBOL(tcp_seq_open);
2098

2099
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2100 2101 2102 2103
{
	int rc = 0;
	struct proc_dir_entry *p;

2104 2105 2106 2107
	afinfo->seq_ops.start		= tcp_seq_start;
	afinfo->seq_ops.next		= tcp_seq_next;
	afinfo->seq_ops.stop		= tcp_seq_stop;

2108
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2109
			     afinfo->seq_fops, afinfo);
2110
	if (!p)
L
Linus Torvalds 已提交
2111 2112 2113
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2114
EXPORT_SYMBOL(tcp_proc_register);
L
Linus Torvalds 已提交
2115

2116
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2117
{
2118
	remove_proc_entry(afinfo->name, net->proc_net);
L
Linus Torvalds 已提交
2119
}
E
Eric Dumazet 已提交
2120
EXPORT_SYMBOL(tcp_proc_unregister);
L
Linus Torvalds 已提交
2121

2122
static void get_openreq4(const struct request_sock *req,
E
Eric Dumazet 已提交
2123
			 struct seq_file *f, int i)
L
Linus Torvalds 已提交
2124
{
2125
	const struct inet_request_sock *ireq = inet_rsk(req);
2126
	long delta = req->rsk_timer.expires - jiffies;
L
Linus Torvalds 已提交
2127

2128
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2129
		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
L
Linus Torvalds 已提交
2130
		i,
2131
		ireq->ir_loc_addr,
2132
		ireq->ir_num,
2133 2134
		ireq->ir_rmt_addr,
		ntohs(ireq->ir_rmt_port),
L
Linus Torvalds 已提交
2135 2136 2137
		TCP_SYN_RECV,
		0, 0, /* could print option size, but that is af dependent. */
		1,    /* timers active (only the expire timer) */
2138
		jiffies_delta_to_clock_t(delta),
2139
		req->num_timeout,
E
Eric Dumazet 已提交
2140 2141
		from_kuid_munged(seq_user_ns(f),
				 sock_i_uid(req->rsk_listener)),
L
Linus Torvalds 已提交
2142 2143
		0,  /* non standard timer */
		0, /* open_requests have no inode */
2144
		0,
2145
		req);
L
Linus Torvalds 已提交
2146 2147
}

2148
static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
L
Linus Torvalds 已提交
2149 2150 2151
{
	int timer_active;
	unsigned long timer_expires;
2152
	const struct tcp_sock *tp = tcp_sk(sk);
2153
	const struct inet_connection_sock *icsk = inet_csk(sk);
2154
	const struct inet_sock *inet = inet_sk(sk);
2155
	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
E
Eric Dumazet 已提交
2156 2157 2158 2159
	__be32 dest = inet->inet_daddr;
	__be32 src = inet->inet_rcv_saddr;
	__u16 destp = ntohs(inet->inet_dport);
	__u16 srcp = ntohs(inet->inet_sport);
2160
	int rx_queue;
L
Linus Torvalds 已提交
2161

N
Nandita Dukkipati 已提交
2162 2163 2164
	if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
	    icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS ||
	    icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
L
Linus Torvalds 已提交
2165
		timer_active	= 1;
2166 2167
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2168
		timer_active	= 4;
2169
		timer_expires	= icsk->icsk_timeout;
2170
	} else if (timer_pending(&sk->sk_timer)) {
L
Linus Torvalds 已提交
2171
		timer_active	= 2;
2172
		timer_expires	= sk->sk_timer.expires;
L
Linus Torvalds 已提交
2173 2174 2175 2176 2177
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

2178 2179 2180 2181 2182 2183 2184 2185
	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);

2186
	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2187
			"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2188
		i, src, srcp, dest, destp, sk->sk_state,
2189
		tp->write_seq - tp->snd_una,
2190
		rx_queue,
L
Linus Torvalds 已提交
2191
		timer_active,
2192
		jiffies_delta_to_clock_t(timer_expires - jiffies),
2193
		icsk->icsk_retransmits,
2194
		from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2195
		icsk->icsk_probes_out,
2196 2197
		sock_i_ino(sk),
		atomic_read(&sk->sk_refcnt), sk,
2198 2199
		jiffies_to_clock_t(icsk->icsk_rto),
		jiffies_to_clock_t(icsk->icsk_ack.ato),
2200
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2201
		tp->snd_cwnd,
2202 2203
		sk->sk_state == TCP_LISTEN ?
		    (fastopenq ? fastopenq->max_qlen : 0) :
2204
		    (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
L
Linus Torvalds 已提交
2205 2206
}

2207
static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2208
			       struct seq_file *f, int i)
L
Linus Torvalds 已提交
2209
{
2210
	long delta = tw->tw_timer.expires - jiffies;
2211
	__be32 dest, src;
L
Linus Torvalds 已提交
2212 2213 2214 2215 2216 2217 2218
	__u16 destp, srcp;

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

2219
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2220
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
L
Linus Torvalds 已提交
2221
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2222
		3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2223
		atomic_read(&tw->tw_refcnt), tw);
L
Linus Torvalds 已提交
2224 2225 2226 2227 2228 2229
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2230
	struct tcp_iter_state *st;
E
Eric Dumazet 已提交
2231
	struct sock *sk = v;
L
Linus Torvalds 已提交
2232

2233
	seq_setwidth(seq, TMPSZ - 1);
L
Linus Torvalds 已提交
2234
	if (v == SEQ_START_TOKEN) {
2235
		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
L
Linus Torvalds 已提交
2236 2237 2238 2239 2240 2241
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
			   "inode");
		goto out;
	}
	st = seq->private;

2242 2243 2244
	if (sk->sk_state == TCP_TIME_WAIT)
		get_timewait4_sock(v, seq, st->num);
	else if (sk->sk_state == TCP_NEW_SYN_RECV)
E
Eric Dumazet 已提交
2245
		get_openreq4(v, seq, st->num);
2246 2247
	else
		get_tcp4_sock(v, seq, st->num);
L
Linus Torvalds 已提交
2248
out:
2249
	seq_pad(seq, '\n');
L
Linus Torvalds 已提交
2250 2251 2252
	return 0;
}

2253 2254 2255 2256 2257 2258 2259 2260
static const struct file_operations tcp_afinfo_seq_fops = {
	.owner   = THIS_MODULE,
	.open    = tcp_seq_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release_net
};

L
Linus Torvalds 已提交
2261 2262 2263
static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.name		= "tcp",
	.family		= AF_INET,
2264
	.seq_fops	= &tcp_afinfo_seq_fops,
2265 2266 2267
	.seq_ops	= {
		.show		= tcp4_seq_show,
	},
L
Linus Torvalds 已提交
2268 2269
};

2270
static int __net_init tcp4_proc_init_net(struct net *net)
2271 2272 2273 2274
{
	return tcp_proc_register(net, &tcp4_seq_afinfo);
}

2275
static void __net_exit tcp4_proc_exit_net(struct net *net)
2276 2277 2278 2279 2280 2281 2282 2283 2284
{
	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
2285 2286
int __init tcp4_proc_init(void)
{
2287
	return register_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2288 2289 2290 2291
}

void tcp4_proc_exit(void)
{
2292
	unregister_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2293 2294 2295 2296 2297 2298 2299 2300 2301
}
#endif /* CONFIG_PROC_FS */

struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2302
	.accept			= inet_csk_accept,
L
Linus Torvalds 已提交
2303 2304 2305 2306 2307 2308 2309
	.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,
2310 2311
	.sendmsg		= tcp_sendmsg,
	.sendpage		= tcp_sendpage,
L
Linus Torvalds 已提交
2312
	.backlog_rcv		= tcp_v4_do_rcv,
E
Eric Dumazet 已提交
2313
	.release_cb		= tcp_release_cb,
2314 2315 2316
	.hash			= inet_hash,
	.unhash			= inet_unhash,
	.get_port		= inet_csk_get_port,
L
Linus Torvalds 已提交
2317
	.enter_memory_pressure	= tcp_enter_memory_pressure,
2318
	.stream_memory_free	= tcp_stream_memory_free,
L
Linus Torvalds 已提交
2319
	.sockets_allocated	= &tcp_sockets_allocated,
2320
	.orphan_count		= &tcp_orphan_count,
L
Linus Torvalds 已提交
2321 2322
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
2323
	.sysctl_mem		= sysctl_tcp_mem,
L
Linus Torvalds 已提交
2324 2325 2326 2327
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2328
	.slab_flags		= SLAB_DESTROY_BY_RCU,
2329
	.twsk_prot		= &tcp_timewait_sock_ops,
2330
	.rsk_prot		= &tcp_request_sock_ops,
2331
	.h.hashinfo		= &tcp_hashinfo,
2332
	.no_autobind		= true,
2333 2334 2335 2336
#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
A
Andrew Morton 已提交
2337
#ifdef CONFIG_MEMCG_KMEM
G
Glauber Costa 已提交
2338 2339 2340 2341
	.init_cgroup		= tcp_init_cgroup,
	.destroy_cgroup		= tcp_destroy_cgroup,
	.proto_cgroup		= tcp_proto_cgroup,
#endif
L
Linus Torvalds 已提交
2342
};
E
Eric Dumazet 已提交
2343
EXPORT_SYMBOL(tcp_prot);
L
Linus Torvalds 已提交
2344

2345 2346 2347 2348 2349 2350 2351 2352 2353
static void __net_exit tcp_sk_exit(struct net *net)
{
	int cpu;

	for_each_possible_cpu(cpu)
		inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
	free_percpu(net->ipv4.tcp_sk);
}

2354 2355
static int __net_init tcp_sk_init(struct net *net)
{
2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370
	int res, cpu;

	net->ipv4.tcp_sk = alloc_percpu(struct sock *);
	if (!net->ipv4.tcp_sk)
		return -ENOMEM;

	for_each_possible_cpu(cpu) {
		struct sock *sk;

		res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
					   IPPROTO_TCP, net);
		if (res)
			goto fail;
		*per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
	}
2371

2372
	net->ipv4.sysctl_tcp_ecn = 2;
2373 2374
	net->ipv4.sysctl_tcp_ecn_fallback = 1;

F
Fan Du 已提交
2375
	net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2376
	net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2377
	net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2378

2379
	return 0;
2380 2381 2382 2383
fail:
	tcp_sk_exit(net);

	return res;
E
Eric W. Biederman 已提交
2384 2385 2386 2387 2388
}

static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
{
	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2389 2390 2391
}

static struct pernet_operations __net_initdata tcp_sk_ops = {
E
Eric W. Biederman 已提交
2392 2393 2394
       .init	   = tcp_sk_init,
       .exit	   = tcp_sk_exit,
       .exit_batch = tcp_sk_exit_batch,
2395 2396
};

2397
void __init tcp_v4_init(void)
L
Linus Torvalds 已提交
2398
{
2399
	inet_hashinfo_init(&tcp_hashinfo);
2400
	if (register_pernet_subsys(&tcp_sk_ops))
L
Linus Torvalds 已提交
2401 2402
		panic("Failed to create the TCP control socket.\n");
}