tcp_ipv4.c 61.4 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/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);
}

540
void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr)
L
Linus Torvalds 已提交
541
{
542
	struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
543

544
	if (skb->ip_summed == CHECKSUM_PARTIAL) {
545
		th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0);
546
		skb->csum_start = skb_transport_header(skb) - skb->head;
A
Al Viro 已提交
547
		skb->csum_offset = offsetof(struct tcphdr, check);
L
Linus Torvalds 已提交
548
	} else {
549
		th->check = tcp_v4_check(skb->len, saddr, daddr,
550
					 csum_partial(th,
L
Linus Torvalds 已提交
551 552 553 554 555
						      th->doff << 2,
						      skb->csum));
	}
}

556
/* This routine computes an IPv4 TCP checksum. */
557
void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
558
{
559
	const struct inet_sock *inet = inet_sk(sk);
560 561 562

	__tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr);
}
E
Eric Dumazet 已提交
563
EXPORT_SYMBOL(tcp_v4_send_check);
564

L
Linus Torvalds 已提交
565 566 567 568 569 570 571 572 573 574 575 576 577
/*
 *	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.
 */

578
static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
579
{
580
	const struct tcphdr *th = tcp_hdr(skb);
581 582 583
	struct {
		struct tcphdr th;
#ifdef CONFIG_TCP_MD5SIG
584
		__be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)];
585 586
#endif
	} rep;
L
Linus Torvalds 已提交
587
	struct ip_reply_arg arg;
588
#ifdef CONFIG_TCP_MD5SIG
589
	struct tcp_md5sig_key *key = NULL;
590 591 592 593
	const __u8 *hash_location = NULL;
	unsigned char newhash[16];
	int genhash;
	struct sock *sk1 = NULL;
594
#endif
595
	struct net *net;
L
Linus Torvalds 已提交
596 597 598 599 600

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

601 602 603 604
	/* 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
605 606 607
		return;

	/* Swap the send and the receive. */
608 609 610 611 612
	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
613 614

	if (th->ack) {
615
		rep.th.seq = th->ack_seq;
L
Linus Torvalds 已提交
616
	} else {
617 618 619
		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
620 621
	}

622
	memset(&arg, 0, sizeof(arg));
623 624 625
	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);

626
	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
627
#ifdef CONFIG_TCP_MD5SIG
628
	hash_location = tcp_parse_md5sig_option(th);
629
	if (sk && sk_fullsock(sk)) {
630 631 632
		key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
					&ip_hdr(skb)->saddr, AF_INET);
	} else if (hash_location) {
633 634 635 636 637 638 639
		/*
		 * 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.
		 */
640
		sk1 = __inet_lookup_listener(net,
641 642
					     &tcp_hashinfo, ip_hdr(skb)->saddr,
					     th->source, ip_hdr(skb)->daddr,
643 644 645 646 647 648 649 650 651 652
					     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;

653
		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb);
654 655 656 657
		if (genhash || memcmp(hash_location, newhash, 16) != 0)
			goto release_sk1;
	}

658 659 660 661 662 663 664 665 666
	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;

667
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
668 669
				     key, ip_hdr(skb)->saddr,
				     ip_hdr(skb)->daddr, &rep.th);
670 671
	}
#endif
672 673
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
674
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
L
Linus Torvalds 已提交
675
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
676 677
	arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0;

678
	/* When socket is gone, all binding information is lost.
A
Alexey Kuznetsov 已提交
679 680
	 * routing might fail in this case. No choice here, if we choose to force
	 * input interface, we will misroute in case of asymmetric route.
681
	 */
A
Alexey Kuznetsov 已提交
682 683
	if (sk)
		arg.bound_dev_if = sk->sk_bound_dev_if;
L
Linus Torvalds 已提交
684

685 686 687
	BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) !=
		     offsetof(struct inet_timewait_sock, tw_bound_dev_if));

688
	arg.tos = ip_hdr(skb)->tos;
689 690
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
691 692
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
693

694 695
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
696 697 698 699 700 701 702 703

#ifdef CONFIG_TCP_MD5SIG
release_sk1:
	if (sk1) {
		rcu_read_unlock();
		sock_put(sk1);
	}
#endif
L
Linus Torvalds 已提交
704 705 706 707 708 709
}

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

710 711
static void tcp_v4_send_ack(struct net *net,
			    struct sk_buff *skb, u32 seq, u32 ack,
712
			    u32 win, u32 tsval, u32 tsecr, int oif,
713
			    struct tcp_md5sig_key *key,
714
			    int reply_flags, u8 tos)
L
Linus Torvalds 已提交
715
{
716
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
717 718
	struct {
		struct tcphdr th;
719
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
720
#ifdef CONFIG_TCP_MD5SIG
721
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
722 723
#endif
			];
L
Linus Torvalds 已提交
724 725 726 727
	} rep;
	struct ip_reply_arg arg;

	memset(&rep.th, 0, sizeof(struct tcphdr));
728
	memset(&arg, 0, sizeof(arg));
L
Linus Torvalds 已提交
729 730 731

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
732
	if (tsecr) {
733 734 735
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
736 737
		rep.opt[1] = htonl(tsval);
		rep.opt[2] = htonl(tsecr);
738
		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
739 740 741 742 743 744 745 746 747 748 749
	}

	/* 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);

750 751
#ifdef CONFIG_TCP_MD5SIG
	if (key) {
752
		int offset = (tsecr) ? 3 : 0;
753 754 755 756 757 758 759 760

		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;

761
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
762 763
				    key, ip_hdr(skb)->saddr,
				    ip_hdr(skb)->daddr, &rep.th);
764 765
	}
#endif
766
	arg.flags = reply_flags;
767 768
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
L
Linus Torvalds 已提交
769 770
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
771 772
	if (oif)
		arg.bound_dev_if = oif;
773
	arg.tos = tos;
774 775
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
776 777
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
778

779
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
L
Linus Torvalds 已提交
780 781 782 783
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
784
	struct inet_timewait_sock *tw = inet_twsk(sk);
785
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
786

787 788
	tcp_v4_send_ack(sock_net(sk), skb,
			tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
789
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
790
			tcp_time_stamp + tcptw->tw_ts_offset,
791 792
			tcptw->tw_ts_recent,
			tw->tw_bound_dev_if,
793
			tcp_twsk_md5_key(tcptw),
794 795
			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
			tw->tw_tos
796
			);
L
Linus Torvalds 已提交
797

798
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
799 800
}

801
static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
802
				  struct request_sock *req)
L
Linus Torvalds 已提交
803
{
804 805 806
	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
	 */
807 808 809 810
	u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 :
					     tcp_sk(sk)->snd_nxt;

	tcp_v4_send_ack(sock_net(sk), skb, seq,
811
			tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd,
812
			tcp_time_stamp,
813 814
			req->ts_recent,
			0,
E
Eric Dumazet 已提交
815 816
			tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
					  AF_INET),
817 818
			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
			ip_hdr(skb)->tos);
L
Linus Torvalds 已提交
819 820 821
}

/*
822
 *	Send a SYN-ACK after having received a SYN.
823
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
824 825
 *	socket.
 */
826
static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
827
			      struct flowi *fl,
828
			      struct request_sock *req,
829 830
			      struct tcp_fastopen_cookie *foc,
				  bool attach_req)
L
Linus Torvalds 已提交
831
{
832
	const struct inet_request_sock *ireq = inet_rsk(req);
833
	struct flowi4 fl4;
L
Linus Torvalds 已提交
834
	int err = -1;
835
	struct sk_buff *skb;
L
Linus Torvalds 已提交
836 837

	/* First, grab a route. */
838
	if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
839
		return -1;
L
Linus Torvalds 已提交
840

841
	skb = tcp_make_synack(sk, dst, req, foc, attach_req);
L
Linus Torvalds 已提交
842 843

	if (skb) {
844
		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
L
Linus Torvalds 已提交
845

846 847
		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
					    ireq->ir_rmt_addr,
848
					    ireq->opt);
849
		err = net_xmit_eval(err);
L
Linus Torvalds 已提交
850 851 852 853 854 855
	}

	return err;
}

/*
856
 *	IPv4 request_sock destructor.
L
Linus Torvalds 已提交
857
 */
858
static void tcp_v4_reqsk_destructor(struct request_sock *req)
L
Linus Torvalds 已提交
859
{
J
Jesper Juhl 已提交
860
	kfree(inet_rsk(req)->opt);
L
Linus Torvalds 已提交
861 862
}

863 864 865 866 867 868 869 870
#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.  */
871
struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
E
Eric Dumazet 已提交
872 873
					 const union tcp_md5_addr *addr,
					 int family)
874
{
875
	const struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
876 877
	struct tcp_md5sig_key *key;
	unsigned int size = sizeof(struct in_addr);
878
	const struct tcp_md5sig_info *md5sig;
879

880 881
	/* caller either holds rcu_read_lock() or socket lock */
	md5sig = rcu_dereference_check(tp->md5sig_info,
882
				       sock_owned_by_user(sk) ||
883
				       lockdep_is_held((spinlock_t *)&sk->sk_lock.slock));
884
	if (!md5sig)
885
		return NULL;
E
Eric Dumazet 已提交
886 887 888 889
#if IS_ENABLED(CONFIG_IPV6)
	if (family == AF_INET6)
		size = sizeof(struct in6_addr);
#endif
890
	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
E
Eric Dumazet 已提交
891 892 893 894
		if (key->family != family)
			continue;
		if (!memcmp(&key->addr, addr, size))
			return key;
895 896 897
	}
	return NULL;
}
E
Eric Dumazet 已提交
898
EXPORT_SYMBOL(tcp_md5_do_lookup);
899

900
struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
901
					 const struct sock *addr_sk)
902
{
903
	const union tcp_md5_addr *addr;
E
Eric Dumazet 已提交
904

905
	addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr;
E
Eric Dumazet 已提交
906
	return tcp_md5_do_lookup(sk, addr, AF_INET);
907 908 909 910
}
EXPORT_SYMBOL(tcp_v4_md5_lookup);

/* This can be called on a newly created socket, from other files */
E
Eric Dumazet 已提交
911 912
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
913 914
{
	/* Add Key to the list */
915
	struct tcp_md5sig_key *key;
916
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
917
	struct tcp_md5sig_info *md5sig;
918

919
	key = tcp_md5_do_lookup(sk, addr, family);
920 921
	if (key) {
		/* Pre-existing entry - just update that one. */
E
Eric Dumazet 已提交
922
		memcpy(key->key, newkey, newkeylen);
923
		key->keylen = newkeylen;
E
Eric Dumazet 已提交
924 925
		return 0;
	}
926

927
	md5sig = rcu_dereference_protected(tp->md5sig_info,
E
Eric Dumazet 已提交
928 929
					   sock_owned_by_user(sk) ||
					   lockdep_is_held(&sk->sk_lock.slock));
E
Eric Dumazet 已提交
930 931 932
	if (!md5sig) {
		md5sig = kmalloc(sizeof(*md5sig), gfp);
		if (!md5sig)
933 934
			return -ENOMEM;

E
Eric Dumazet 已提交
935 936
		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
		INIT_HLIST_HEAD(&md5sig->head);
937
		rcu_assign_pointer(tp->md5sig_info, md5sig);
E
Eric Dumazet 已提交
938
	}
939

940
	key = sock_kmalloc(sk, sizeof(*key), gfp);
E
Eric Dumazet 已提交
941 942
	if (!key)
		return -ENOMEM;
943
	if (!tcp_alloc_md5sig_pool()) {
944
		sock_kfree_s(sk, key, sizeof(*key));
E
Eric Dumazet 已提交
945
		return -ENOMEM;
946
	}
E
Eric Dumazet 已提交
947 948 949 950 951 952 953 954

	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);
955 956
	return 0;
}
E
Eric Dumazet 已提交
957
EXPORT_SYMBOL(tcp_md5_do_add);
958

E
Eric Dumazet 已提交
959
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
960
{
E
Eric Dumazet 已提交
961 962
	struct tcp_md5sig_key *key;

963
	key = tcp_md5_do_lookup(sk, addr, family);
E
Eric Dumazet 已提交
964 965 966
	if (!key)
		return -ENOENT;
	hlist_del_rcu(&key->node);
967
	atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
968 969
	kfree_rcu(key, rcu);
	return 0;
970
}
E
Eric Dumazet 已提交
971
EXPORT_SYMBOL(tcp_md5_do_del);
972

973
static void tcp_clear_md5_list(struct sock *sk)
974 975
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
976
	struct tcp_md5sig_key *key;
977
	struct hlist_node *n;
978
	struct tcp_md5sig_info *md5sig;
979

980 981
	md5sig = rcu_dereference_protected(tp->md5sig_info, 1);

982
	hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
E
Eric Dumazet 已提交
983
		hlist_del_rcu(&key->node);
984
		atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
985
		kfree_rcu(key, rcu);
986 987 988
	}
}

989 990
static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
				 int optlen)
991 992 993 994 995 996 997
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;

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

998
	if (copy_from_user(&cmd, optval, sizeof(cmd)))
999 1000 1001 1002 1003
		return -EFAULT;

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

1004
	if (!cmd.tcpm_keylen)
E
Eric Dumazet 已提交
1005 1006
		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
				      AF_INET);
1007 1008 1009 1010

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

E
Eric Dumazet 已提交
1011 1012 1013
	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);
1014 1015
}

1016 1017
static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
					__be32 daddr, __be32 saddr, int nbytes)
1018 1019
{
	struct tcp4_pseudohdr *bp;
1020
	struct scatterlist sg;
1021 1022 1023 1024

	bp = &hp->md5_blk.ip4;

	/*
1025
	 * 1. the TCP pseudo-header (in the order: source IP address,
1026 1027 1028 1029 1030 1031
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
1032
	bp->protocol = IPPROTO_TCP;
1033
	bp->len = cpu_to_be16(nbytes);
1034

1035 1036 1037 1038
	sg_init_one(&sg, bp, sizeof(*bp));
	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
}

E
Eric Dumazet 已提交
1039
static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1040
			       __be32 daddr, __be32 saddr, const struct tcphdr *th)
1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058
{
	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))
1059 1060 1061 1062
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;
1063

1064 1065 1066 1067
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
1068
	return 1;
1069 1070
}

1071 1072
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
1073
			const struct sk_buff *skb)
1074
{
1075 1076
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
E
Eric Dumazet 已提交
1077
	const struct tcphdr *th = tcp_hdr(skb);
1078 1079
	__be32 saddr, daddr;

1080 1081 1082
	if (sk) { /* valid for establish/request sockets */
		saddr = sk->sk_rcv_saddr;
		daddr = sk->sk_daddr;
1083
	} else {
1084 1085 1086
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
1087
	}
1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115

	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;
1116
}
1117
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1118

1119 1120
#endif

1121
/* Called with rcu_read_lock() */
1122
static bool tcp_v4_inbound_md5_hash(const struct sock *sk,
1123
				    const struct sk_buff *skb)
1124
{
1125
#ifdef CONFIG_TCP_MD5SIG
1126 1127 1128 1129 1130 1131 1132 1133
	/*
	 * 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.
	 */
1134
	const __u8 *hash_location = NULL;
1135
	struct tcp_md5sig_key *hash_expected;
1136
	const struct iphdr *iph = ip_hdr(skb);
1137
	const struct tcphdr *th = tcp_hdr(skb);
1138 1139 1140
	int genhash;
	unsigned char newhash[16];

E
Eric Dumazet 已提交
1141 1142
	hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
					  AF_INET);
1143
	hash_location = tcp_parse_md5sig_option(th);
1144 1145 1146

	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
E
Eric Dumazet 已提交
1147
		return false;
1148 1149

	if (hash_expected && !hash_location) {
1150
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
E
Eric Dumazet 已提交
1151
		return true;
1152 1153 1154
	}

	if (!hash_expected && hash_location) {
1155
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
E
Eric Dumazet 已提交
1156
		return true;
1157 1158 1159 1160 1161
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
1162 1163
	genhash = tcp_v4_md5_hash_skb(newhash,
				      hash_expected,
1164
				      NULL, skb);
1165 1166

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1167 1168 1169 1170 1171
		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
1172
		return true;
1173
	}
E
Eric Dumazet 已提交
1174
	return false;
1175
#endif
1176 1177
	return false;
}
1178

1179 1180
static void tcp_v4_init_req(struct request_sock *req,
			    const struct sock *sk_listener,
1181 1182 1183 1184
			    struct sk_buff *skb)
{
	struct inet_request_sock *ireq = inet_rsk(req);

1185 1186 1187
	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;
1188 1189 1190
	ireq->opt = tcp_v4_save_options(skb);
}

1191 1192
static struct dst_entry *tcp_v4_route_req(const struct sock *sk,
					  struct flowi *fl,
1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207
					  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;
}

1208
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1209
	.family		=	PF_INET,
1210
	.obj_size	=	sizeof(struct tcp_request_sock),
1211
	.rtx_syn_ack	=	tcp_rtx_synack,
1212 1213
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1214
	.send_reset	=	tcp_v4_send_reset,
S
stephen hemminger 已提交
1215
	.syn_ack_timeout =	tcp_syn_ack_timeout,
L
Linus Torvalds 已提交
1216 1217
};

1218
static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1219
	.mss_clamp	=	TCP_MSS_DEFAULT,
1220
#ifdef CONFIG_TCP_MD5SIG
1221
	.req_md5_lookup	=	tcp_v4_md5_lookup,
1222
	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1223
#endif
1224
	.init_req	=	tcp_v4_init_req,
1225 1226 1227
#ifdef CONFIG_SYN_COOKIES
	.cookie_init_seq =	cookie_v4_init_sequence,
#endif
1228
	.route_req	=	tcp_v4_route_req,
1229
	.init_seq	=	tcp_v4_init_sequence,
1230
	.send_synack	=	tcp_v4_send_synack,
1231
};
1232

L
Linus Torvalds 已提交
1233 1234 1235
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
1236
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
L
Linus Torvalds 已提交
1237 1238
		goto drop;

O
Octavian Purdila 已提交
1239 1240
	return tcp_conn_request(&tcp_request_sock_ops,
				&tcp_request_sock_ipv4_ops, sk, skb);
L
Linus Torvalds 已提交
1241 1242

drop:
1243
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1244 1245
	return 0;
}
E
Eric Dumazet 已提交
1246
EXPORT_SYMBOL(tcp_v4_conn_request);
L
Linus Torvalds 已提交
1247 1248 1249 1250 1251 1252


/*
 * The three way handshake has completed - we got a valid synack -
 * now create the new socket.
 */
1253
struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
1254
				  struct request_sock *req,
1255 1256 1257
				  struct dst_entry *dst,
				  struct request_sock *req_unhash,
				  bool *own_req)
L
Linus Torvalds 已提交
1258
{
1259
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1260 1261 1262
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1263 1264 1265
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
1266
	struct ip_options_rcu *inet_opt;
L
Linus Torvalds 已提交
1267 1268 1269 1270 1271 1272

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
1273
		goto exit_nonewsk;
L
Linus Torvalds 已提交
1274

1275
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1276
	inet_sk_rx_dst_set(newsk, skb);
L
Linus Torvalds 已提交
1277 1278 1279

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1280
	ireq		      = inet_rsk(req);
1281 1282
	sk_daddr_set(newsk, ireq->ir_rmt_addr);
	sk_rcv_saddr_set(newsk, ireq->ir_loc_addr);
1283
	newsk->sk_bound_dev_if = ireq->ir_iif;
1284
	newinet->inet_saddr	      = ireq->ir_loc_addr;
1285 1286
	inet_opt	      = ireq->opt;
	rcu_assign_pointer(newinet->inet_opt, inet_opt);
1287
	ireq->opt	      = NULL;
1288
	newinet->mc_index     = inet_iif(skb);
1289
	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
1290
	newinet->rcv_tos      = ip_hdr(skb)->tos;
1291
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1292 1293
	if (inet_opt)
		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
E
Eric Dumazet 已提交
1294
	newinet->inet_id = newtp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
1295

E
Eric Dumazet 已提交
1296 1297 1298 1299 1300 1301 1302
	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() */
	}
1303 1304
	sk_setup_caps(newsk, dst);

1305 1306
	tcp_ca_openreq_child(newsk, dst);

L
Linus Torvalds 已提交
1307
	tcp_sync_mss(newsk, dst_mtu(dst));
1308
	newtp->advmss = dst_metric_advmss(dst);
1309 1310 1311 1312
	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
1313 1314
	tcp_initialize_rcv_mss(newsk);

1315 1316
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
E
Eric Dumazet 已提交
1317 1318
	key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
				AF_INET);
1319
	if (key) {
1320 1321 1322 1323 1324 1325
		/*
		 * 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
1326 1327
		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
1328
		sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1329 1330 1331
	}
#endif

1332 1333
	if (__inet_inherit_port(sk, newsk) < 0)
		goto put_and_exit;
1334
	*own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash));
E
Eric Dumazet 已提交
1335
	if (*own_req)
1336
		tcp_move_syn(newtp, req);
L
Linus Torvalds 已提交
1337 1338 1339 1340

	return newsk;

exit_overflow:
1341
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1342 1343
exit_nonewsk:
	dst_release(dst);
L
Linus Torvalds 已提交
1344
exit:
1345
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1346
	return NULL;
1347
put_and_exit:
1348 1349
	inet_csk_prepare_forced_close(newsk);
	tcp_done(newsk);
1350
	goto exit;
L
Linus Torvalds 已提交
1351
}
E
Eric Dumazet 已提交
1352
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
L
Linus Torvalds 已提交
1353

1354
static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb)
L
Linus Torvalds 已提交
1355
{
1356
#ifdef CONFIG_SYN_COOKIES
1357
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1358

1359
	if (!th->syn)
C
Cong Wang 已提交
1360
		sk = cookie_v4_check(sk, skb);
L
Linus Torvalds 已提交
1361 1362 1363 1364 1365
#endif
	return sk;
}

/* The socket must have it's spinlock held when we get
1366
 * here, unless it is a TCP_LISTEN socket.
L
Linus Torvalds 已提交
1367 1368 1369 1370 1371 1372 1373 1374
 *
 * 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)
{
1375 1376
	struct sock *rsk;

L
Linus Torvalds 已提交
1377
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1378 1379
		struct dst_entry *dst = sk->sk_rx_dst;

1380
		sock_rps_save_rxhash(sk, skb);
1381
		sk_mark_napi_id(sk, skb);
1382
		if (dst) {
E
Eric Dumazet 已提交
1383
			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
1384
			    !dst->ops->check(dst, 0)) {
1385 1386 1387 1388
				dst_release(dst);
				sk->sk_rx_dst = NULL;
			}
		}
1389
		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
L
Linus Torvalds 已提交
1390 1391 1392
		return 0;
	}

E
Eric Dumazet 已提交
1393
	if (tcp_checksum_complete(skb))
L
Linus Torvalds 已提交
1394 1395 1396
		goto csum_err;

	if (sk->sk_state == TCP_LISTEN) {
1397 1398
		struct sock *nsk = tcp_v4_cookie_check(sk, skb);

L
Linus Torvalds 已提交
1399 1400 1401
		if (!nsk)
			goto discard;
		if (nsk != sk) {
1402
			sock_rps_save_rxhash(nsk, skb);
1403
			sk_mark_napi_id(nsk, skb);
1404 1405
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1406
				goto reset;
1407
			}
L
Linus Torvalds 已提交
1408 1409
			return 0;
		}
1410
	} else
1411
		sock_rps_save_rxhash(sk, skb);
1412

1413
	if (tcp_rcv_state_process(sk, skb)) {
1414
		rsk = sk;
L
Linus Torvalds 已提交
1415
		goto reset;
1416
	}
L
Linus Torvalds 已提交
1417 1418 1419
	return 0;

reset:
1420
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1421 1422 1423 1424 1425 1426 1427 1428 1429 1430
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:
1431
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1432
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1433 1434
	goto discard;
}
E
Eric Dumazet 已提交
1435
EXPORT_SYMBOL(tcp_v4_do_rcv);
L
Linus Torvalds 已提交
1436

1437
void tcp_v4_early_demux(struct sk_buff *skb)
D
David S. Miller 已提交
1438 1439 1440 1441 1442 1443
{
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct sock *sk;

	if (skb->pkt_type != PACKET_HOST)
1444
		return;
D
David S. Miller 已提交
1445

1446
	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1447
		return;
D
David S. Miller 已提交
1448 1449

	iph = ip_hdr(skb);
1450
	th = tcp_hdr(skb);
D
David S. Miller 已提交
1451 1452

	if (th->doff < sizeof(struct tcphdr) / 4)
1453
		return;
D
David S. Miller 已提交
1454

1455
	sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
D
David S. Miller 已提交
1456
				       iph->saddr, th->source,
1457
				       iph->daddr, ntohs(th->dest),
E
Eric Dumazet 已提交
1458
				       skb->skb_iif);
D
David S. Miller 已提交
1459 1460 1461
	if (sk) {
		skb->sk = sk;
		skb->destructor = sock_edemux;
1462
		if (sk_fullsock(sk)) {
1463
			struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst);
E
Eric Dumazet 已提交
1464

D
David S. Miller 已提交
1465 1466
			if (dst)
				dst = dst_check(dst, 0);
1467
			if (dst &&
E
Eric Dumazet 已提交
1468
			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1469
				skb_dst_set_noref(skb, dst);
D
David S. Miller 已提交
1470 1471 1472 1473
		}
	}
}

E
Eric Dumazet 已提交
1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491
/* 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;

1492 1493 1494 1495 1496 1497 1498 1499 1500
	/* 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
E
Eric Dumazet 已提交
1501
		skb_dst_force_safe(skb);
1502

E
Eric Dumazet 已提交
1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528
	__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
1529 1530 1531 1532 1533 1534
/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
1535
	const struct iphdr *iph;
1536
	const struct tcphdr *th;
L
Linus Torvalds 已提交
1537 1538
	struct sock *sk;
	int ret;
1539
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
1540 1541 1542 1543 1544

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

	/* Count it even if it's bad */
1545
	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
L
Linus Torvalds 已提交
1546 1547 1548 1549

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

1550
	th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1551 1552 1553 1554 1555 1556 1557 1558

	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
1559
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1560
	 * So, we defer the checks. */
1561 1562

	if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1563
		goto csum_error;
L
Linus Torvalds 已提交
1564

1565
	th = tcp_hdr(skb);
1566
	iph = ip_hdr(skb);
1567 1568 1569 1570 1571 1572 1573
	/* 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
1574 1575 1576 1577
	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);
1578
	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1579
	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1580
	TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
L
Linus Torvalds 已提交
1581 1582
	TCP_SKB_CB(skb)->sacked	 = 0;

1583
lookup:
1584
	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
L
Linus Torvalds 已提交
1585 1586 1587
	if (!sk)
		goto no_tcp_socket;

E
Eric Dumazet 已提交
1588 1589 1590 1591
process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

1592 1593 1594 1595 1596 1597 1598
	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;
1599
		if (likely(sk->sk_state == TCP_LISTEN)) {
1600
			nsk = tcp_check_req(sk, skb, req, false);
1601
		} else {
1602
			inet_csk_reqsk_queue_drop_and_put(sk, req);
1603 1604
			goto lookup;
		}
1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618
		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;
		}
	}
1619 1620
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1621
		goto discard_and_relse;
1622
	}
1623

L
Linus Torvalds 已提交
1624 1625
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1626 1627 1628 1629

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

1630
	nf_reset(skb);
L
Linus Torvalds 已提交
1631

1632
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1633 1634 1635 1636
		goto discard_and_relse;

	skb->dev = NULL;

1637 1638 1639 1640 1641 1642 1643
	if (sk->sk_state == TCP_LISTEN) {
		ret = tcp_v4_do_rcv(sk, skb);
		goto put_and_return;
	}

	sk_incoming_cpu_update(sk);

1644
	bh_lock_sock_nested(sk);
1645
	tcp_sk(sk)->segs_in += max_t(u16, 1, skb_shinfo(skb)->gso_segs);
L
Linus Torvalds 已提交
1646 1647
	ret = 0;
	if (!sock_owned_by_user(sk)) {
D
Dan Williams 已提交
1648
		if (!tcp_prequeue(sk, skb))
L
Linus Torvalds 已提交
1649
			ret = tcp_v4_do_rcv(sk, skb);
1650 1651
	} else if (unlikely(sk_add_backlog(sk, skb,
					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
Z
Zhu Yi 已提交
1652
		bh_unlock_sock(sk);
1653
		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
Z
Zhu Yi 已提交
1654 1655
		goto discard_and_relse;
	}
L
Linus Torvalds 已提交
1656 1657
	bh_unlock_sock(sk);

1658
put_and_return:
L
Linus Torvalds 已提交
1659 1660 1661 1662 1663 1664 1665 1666
	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
1667
	if (tcp_checksum_complete(skb)) {
1668 1669
csum_error:
		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
L
Linus Torvalds 已提交
1670
bad_packet:
1671
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1672
	} else {
1673
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1674 1675 1676 1677 1678
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
1679
	return 0;
L
Linus Torvalds 已提交
1680 1681 1682 1683 1684 1685 1686

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1687
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1688 1689 1690
		goto discard_it;
	}

1691 1692 1693
	if (tcp_checksum_complete(skb)) {
		inet_twsk_put(inet_twsk(sk));
		goto csum_error;
L
Linus Torvalds 已提交
1694
	}
1695
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1696
	case TCP_TW_SYN: {
1697
		struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1698
							&tcp_hashinfo,
1699
							iph->saddr, th->source,
1700
							iph->daddr, th->dest,
1701
							inet_iif(skb));
L
Linus Torvalds 已提交
1702
		if (sk2) {
1703
			inet_twsk_deschedule_put(inet_twsk(sk));
L
Linus Torvalds 已提交
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:
1713 1714 1715
		tcp_v4_send_reset(sk, skb);
		inet_twsk_deschedule_put(inet_twsk(sk));
		goto discard_it;
L
Linus Torvalds 已提交
1716 1717 1718 1719 1720
	case TCP_TW_SUCCESS:;
	}
	goto discard_it;
}

1721 1722 1723 1724 1725
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
1726

1727
void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
E
Eric Dumazet 已提交
1728 1729 1730
{
	struct dst_entry *dst = skb_dst(skb);

E
Eric Dumazet 已提交
1731
	if (dst && dst_hold_safe(dst)) {
1732 1733 1734
		sk->sk_rx_dst = dst;
		inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
	}
E
Eric Dumazet 已提交
1735
}
1736
EXPORT_SYMBOL(inet_sk_rx_dst_set);
E
Eric Dumazet 已提交
1737

1738
const struct inet_connection_sock_af_ops ipv4_specific = {
1739 1740 1741
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
E
Eric Dumazet 已提交
1742
	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1743 1744 1745 1746 1747 1748 1749
	.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),
1750
	.bind_conflict	   = inet_csk_bind_conflict,
1751
#ifdef CONFIG_COMPAT
1752 1753
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1754
#endif
1755
	.mtu_reduced	   = tcp_v4_mtu_reduced,
L
Linus Torvalds 已提交
1756
};
E
Eric Dumazet 已提交
1757
EXPORT_SYMBOL(ipv4_specific);
L
Linus Torvalds 已提交
1758

1759
#ifdef CONFIG_TCP_MD5SIG
1760
static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1761
	.md5_lookup		= tcp_v4_md5_lookup,
1762
	.calc_md5_hash		= tcp_v4_md5_hash_skb,
1763 1764
	.md5_parse		= tcp_v4_parse_md5_keys,
};
1765
#endif
1766

L
Linus Torvalds 已提交
1767 1768 1769 1770 1771
/* 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)
{
1772
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1773

1774
	tcp_init_sock(sk);
L
Linus Torvalds 已提交
1775

1776
	icsk->icsk_af_ops = &ipv4_specific;
1777

1778
#ifdef CONFIG_TCP_MD5SIG
1779
	tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1780
#endif
L
Linus Torvalds 已提交
1781 1782 1783 1784

	return 0;
}

1785
void tcp_v4_destroy_sock(struct sock *sk)
L
Linus Torvalds 已提交
1786 1787 1788 1789 1790
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1791
	tcp_cleanup_congestion_control(sk);
1792

L
Linus Torvalds 已提交
1793
	/* Cleanup up the write buffer. */
1794
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
1795 1796

	/* Cleans up our, hopefully empty, out_of_order_queue. */
1797
	__skb_queue_purge(&tp->out_of_order_queue);
L
Linus Torvalds 已提交
1798

1799 1800 1801
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
E
Eric Dumazet 已提交
1802
		tcp_clear_md5_list(sk);
1803
		kfree_rcu(tp->md5sig_info, rcu);
1804 1805 1806
		tp->md5sig_info = NULL;
	}
#endif
C
Chris Leech 已提交
1807

L
Linus Torvalds 已提交
1808 1809 1810 1811
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1812
	if (inet_csk(sk)->icsk_bind_hash)
1813
		inet_put_port(sk);
L
Linus Torvalds 已提交
1814

1815
	BUG_ON(tp->fastopen_rsk);
1816

1817 1818
	/* If socket is aborted during connect operation */
	tcp_free_fastopen_req(tp);
1819
	tcp_saved_syn_free(tp);
1820

1821
	sk_sockets_allocated_dec(sk);
1822

1823
	if (mem_cgroup_sockets_enabled && sk->sk_memcg)
1824
		sock_release_memcg(sk);
L
Linus Torvalds 已提交
1825 1826 1827 1828 1829 1830
}
EXPORT_SYMBOL(tcp_v4_destroy_sock);

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

1831 1832 1833 1834 1835
/*
 * 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
1836 1837
static void *listening_get_next(struct seq_file *seq, void *cur)
{
1838
	struct inet_connection_sock *icsk;
1839
	struct hlist_nulls_node *node;
L
Linus Torvalds 已提交
1840
	struct sock *sk = cur;
1841
	struct inet_listen_hashbucket *ilb;
J
Jianjun Kong 已提交
1842
	struct tcp_iter_state *st = seq->private;
1843
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1844 1845

	if (!sk) {
1846
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
1847
		spin_lock_bh(&ilb->lock);
1848
		sk = sk_nulls_head(&ilb->head);
1849
		st->offset = 0;
L
Linus Torvalds 已提交
1850 1851
		goto get_sk;
	}
1852
	ilb = &tcp_hashinfo.listening_hash[st->bucket];
L
Linus Torvalds 已提交
1853
	++st->num;
1854
	++st->offset;
L
Linus Torvalds 已提交
1855

1856
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1857
get_sk:
1858
	sk_nulls_for_each_from(sk, node) {
1859 1860 1861
		if (!net_eq(sock_net(sk), net))
			continue;
		if (sk->sk_family == st->family) {
L
Linus Torvalds 已提交
1862 1863 1864
			cur = sk;
			goto out;
		}
1865
		icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1866
	}
1867
	spin_unlock_bh(&ilb->lock);
1868
	st->offset = 0;
1869
	if (++st->bucket < INET_LHTABLE_SIZE) {
1870 1871
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
		spin_lock_bh(&ilb->lock);
1872
		sk = sk_nulls_head(&ilb->head);
L
Linus Torvalds 已提交
1873 1874 1875 1876 1877 1878 1879 1880 1881
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
1882 1883 1884 1885 1886 1887
	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
1888 1889 1890 1891 1892 1893 1894 1895

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

E
Eric Dumazet 已提交
1896
static inline bool empty_bucket(const struct tcp_iter_state *st)
1897
{
E
Eric Dumazet 已提交
1898
	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1899 1900
}

1901 1902 1903 1904
/*
 * 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
1905 1906
static void *established_get_first(struct seq_file *seq)
{
J
Jianjun Kong 已提交
1907
	struct tcp_iter_state *st = seq->private;
1908
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1909 1910
	void *rc = NULL;

1911 1912
	st->offset = 0;
	for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
L
Linus Torvalds 已提交
1913
		struct sock *sk;
1914
		struct hlist_nulls_node *node;
1915
		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
L
Linus Torvalds 已提交
1916

1917 1918 1919 1920
		/* Lockless fast path for the common case of empty buckets */
		if (empty_bucket(st))
			continue;

1921
		spin_lock_bh(lock);
1922
		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1923
			if (sk->sk_family != st->family ||
1924
			    !net_eq(sock_net(sk), net)) {
L
Linus Torvalds 已提交
1925 1926 1927 1928 1929
				continue;
			}
			rc = sk;
			goto out;
		}
1930
		spin_unlock_bh(lock);
L
Linus Torvalds 已提交
1931 1932 1933 1934 1935 1936 1937 1938
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
1939
	struct hlist_nulls_node *node;
J
Jianjun Kong 已提交
1940
	struct tcp_iter_state *st = seq->private;
1941
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1942 1943

	++st->num;
1944
	++st->offset;
L
Linus Torvalds 已提交
1945

E
Eric Dumazet 已提交
1946
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1947

1948
	sk_nulls_for_each_from(sk, node) {
1949
		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
E
Eric Dumazet 已提交
1950
			return sk;
L
Linus Torvalds 已提交
1951 1952
	}

E
Eric Dumazet 已提交
1953 1954 1955
	spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
	++st->bucket;
	return established_get_first(seq);
L
Linus Torvalds 已提交
1956 1957 1958 1959
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
1960 1961 1962 1963 1964
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	rc = established_get_first(seq);
L
Linus Torvalds 已提交
1965 1966 1967 1968

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
1969
	}
L
Linus Torvalds 已提交
1970 1971 1972 1973 1974 1975
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
J
Jianjun Kong 已提交
1976
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988

	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;
}

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
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
2007
		st->state = TCP_SEQ_STATE_ESTABLISHED;
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
		/* 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
2022 2023
static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
J
Jianjun Kong 已提交
2024
	struct tcp_iter_state *st = seq->private;
2025 2026 2027 2028 2029 2030 2031 2032
	void *rc;

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

L
Linus Torvalds 已提交
2033 2034
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
2035 2036 2037 2038 2039 2040 2041
	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
2042 2043 2044 2045
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2046
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058
	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;
2059 2060
			st->bucket = 0;
			st->offset = 0;
L
Linus Torvalds 已提交
2061 2062 2063 2064 2065 2066 2067 2068 2069
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
2070
	st->last_pos = *pos;
L
Linus Torvalds 已提交
2071 2072 2073 2074 2075
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2076
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2077 2078 2079 2080

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2081
			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
L
Linus Torvalds 已提交
2082 2083 2084
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2085
			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2086 2087 2088 2089
		break;
	}
}

2090
int tcp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2091
{
A
Al Viro 已提交
2092
	struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
L
Linus Torvalds 已提交
2093
	struct tcp_iter_state *s;
2094
	int err;
L
Linus Torvalds 已提交
2095

2096 2097 2098 2099
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			  sizeof(struct tcp_iter_state));
	if (err < 0)
		return err;
2100

2101
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2102
	s->family		= afinfo->family;
S
stephen hemminger 已提交
2103
	s->last_pos		= 0;
2104 2105
	return 0;
}
2106
EXPORT_SYMBOL(tcp_seq_open);
2107

2108
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2109 2110 2111 2112
{
	int rc = 0;
	struct proc_dir_entry *p;

2113 2114 2115 2116
	afinfo->seq_ops.start		= tcp_seq_start;
	afinfo->seq_ops.next		= tcp_seq_next;
	afinfo->seq_ops.stop		= tcp_seq_stop;

2117
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2118
			     afinfo->seq_fops, afinfo);
2119
	if (!p)
L
Linus Torvalds 已提交
2120 2121 2122
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2123
EXPORT_SYMBOL(tcp_proc_register);
L
Linus Torvalds 已提交
2124

2125
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2126
{
2127
	remove_proc_entry(afinfo->name, net->proc_net);
L
Linus Torvalds 已提交
2128
}
E
Eric Dumazet 已提交
2129
EXPORT_SYMBOL(tcp_proc_unregister);
L
Linus Torvalds 已提交
2130

2131
static void get_openreq4(const struct request_sock *req,
E
Eric Dumazet 已提交
2132
			 struct seq_file *f, int i)
L
Linus Torvalds 已提交
2133
{
2134
	const struct inet_request_sock *ireq = inet_rsk(req);
2135
	long delta = req->rsk_timer.expires - jiffies;
L
Linus Torvalds 已提交
2136

2137
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2138
		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
L
Linus Torvalds 已提交
2139
		i,
2140
		ireq->ir_loc_addr,
2141
		ireq->ir_num,
2142 2143
		ireq->ir_rmt_addr,
		ntohs(ireq->ir_rmt_port),
L
Linus Torvalds 已提交
2144 2145 2146
		TCP_SYN_RECV,
		0, 0, /* could print option size, but that is af dependent. */
		1,    /* timers active (only the expire timer) */
2147
		jiffies_delta_to_clock_t(delta),
2148
		req->num_timeout,
E
Eric Dumazet 已提交
2149 2150
		from_kuid_munged(seq_user_ns(f),
				 sock_i_uid(req->rsk_listener)),
L
Linus Torvalds 已提交
2151 2152
		0,  /* non standard timer */
		0, /* open_requests have no inode */
2153
		0,
2154
		req);
L
Linus Torvalds 已提交
2155 2156
}

2157
static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
L
Linus Torvalds 已提交
2158 2159 2160
{
	int timer_active;
	unsigned long timer_expires;
2161
	const struct tcp_sock *tp = tcp_sk(sk);
2162
	const struct inet_connection_sock *icsk = inet_csk(sk);
2163
	const struct inet_sock *inet = inet_sk(sk);
2164
	const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq;
E
Eric Dumazet 已提交
2165 2166 2167 2168
	__be32 dest = inet->inet_daddr;
	__be32 src = inet->inet_rcv_saddr;
	__u16 destp = ntohs(inet->inet_dport);
	__u16 srcp = ntohs(inet->inet_sport);
2169
	int rx_queue;
2170
	int state;
L
Linus Torvalds 已提交
2171

N
Nandita Dukkipati 已提交
2172 2173 2174
	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
2175
		timer_active	= 1;
2176 2177
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2178
		timer_active	= 4;
2179
		timer_expires	= icsk->icsk_timeout;
2180
	} else if (timer_pending(&sk->sk_timer)) {
L
Linus Torvalds 已提交
2181
		timer_active	= 2;
2182
		timer_expires	= sk->sk_timer.expires;
L
Linus Torvalds 已提交
2183 2184 2185 2186 2187
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

2188 2189
	state = sk_state_load(sk);
	if (state == TCP_LISTEN)
2190 2191
		rx_queue = sk->sk_ack_backlog;
	else
2192 2193
		/* Because we don't lock the socket,
		 * we might find a transient negative value.
2194 2195 2196
		 */
		rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);

2197
	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2198
			"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2199
		i, src, srcp, dest, destp, state,
2200
		tp->write_seq - tp->snd_una,
2201
		rx_queue,
L
Linus Torvalds 已提交
2202
		timer_active,
2203
		jiffies_delta_to_clock_t(timer_expires - jiffies),
2204
		icsk->icsk_retransmits,
2205
		from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2206
		icsk->icsk_probes_out,
2207 2208
		sock_i_ino(sk),
		atomic_read(&sk->sk_refcnt), sk,
2209 2210
		jiffies_to_clock_t(icsk->icsk_rto),
		jiffies_to_clock_t(icsk->icsk_ack.ato),
2211
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2212
		tp->snd_cwnd,
2213 2214
		state == TCP_LISTEN ?
		    fastopenq->max_qlen :
2215
		    (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
L
Linus Torvalds 已提交
2216 2217
}

2218
static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2219
			       struct seq_file *f, int i)
L
Linus Torvalds 已提交
2220
{
2221
	long delta = tw->tw_timer.expires - jiffies;
2222
	__be32 dest, src;
L
Linus Torvalds 已提交
2223 2224 2225 2226 2227 2228 2229
	__u16 destp, srcp;

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

2230
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2231
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
L
Linus Torvalds 已提交
2232
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2233
		3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2234
		atomic_read(&tw->tw_refcnt), tw);
L
Linus Torvalds 已提交
2235 2236 2237 2238 2239 2240
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2241
	struct tcp_iter_state *st;
E
Eric Dumazet 已提交
2242
	struct sock *sk = v;
L
Linus Torvalds 已提交
2243

2244
	seq_setwidth(seq, TMPSZ - 1);
L
Linus Torvalds 已提交
2245
	if (v == SEQ_START_TOKEN) {
2246
		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
L
Linus Torvalds 已提交
2247 2248 2249 2250 2251 2252
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
			   "inode");
		goto out;
	}
	st = seq->private;

2253 2254 2255
	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
2256
		get_openreq4(v, seq, st->num);
2257 2258
	else
		get_tcp4_sock(v, seq, st->num);
L
Linus Torvalds 已提交
2259
out:
2260
	seq_pad(seq, '\n');
L
Linus Torvalds 已提交
2261 2262 2263
	return 0;
}

2264 2265 2266 2267 2268 2269 2270 2271
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
2272 2273 2274
static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.name		= "tcp",
	.family		= AF_INET,
2275
	.seq_fops	= &tcp_afinfo_seq_fops,
2276 2277 2278
	.seq_ops	= {
		.show		= tcp4_seq_show,
	},
L
Linus Torvalds 已提交
2279 2280
};

2281
static int __net_init tcp4_proc_init_net(struct net *net)
2282 2283 2284 2285
{
	return tcp_proc_register(net, &tcp4_seq_afinfo);
}

2286
static void __net_exit tcp4_proc_exit_net(struct net *net)
2287 2288 2289 2290 2291 2292 2293 2294 2295
{
	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
2296 2297
int __init tcp4_proc_init(void)
{
2298
	return register_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2299 2300 2301 2302
}

void tcp4_proc_exit(void)
{
2303
	unregister_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2304 2305 2306 2307 2308 2309 2310 2311 2312
}
#endif /* CONFIG_PROC_FS */

struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2313
	.accept			= inet_csk_accept,
L
Linus Torvalds 已提交
2314 2315 2316 2317 2318 2319 2320
	.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,
2321 2322
	.sendmsg		= tcp_sendmsg,
	.sendpage		= tcp_sendpage,
L
Linus Torvalds 已提交
2323
	.backlog_rcv		= tcp_v4_do_rcv,
E
Eric Dumazet 已提交
2324
	.release_cb		= tcp_release_cb,
2325 2326 2327
	.hash			= inet_hash,
	.unhash			= inet_unhash,
	.get_port		= inet_csk_get_port,
L
Linus Torvalds 已提交
2328
	.enter_memory_pressure	= tcp_enter_memory_pressure,
2329
	.stream_memory_free	= tcp_stream_memory_free,
L
Linus Torvalds 已提交
2330
	.sockets_allocated	= &tcp_sockets_allocated,
2331
	.orphan_count		= &tcp_orphan_count,
L
Linus Torvalds 已提交
2332 2333
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
2334
	.sysctl_mem		= sysctl_tcp_mem,
L
Linus Torvalds 已提交
2335 2336 2337 2338
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2339
	.slab_flags		= SLAB_DESTROY_BY_RCU,
2340
	.twsk_prot		= &tcp_timewait_sock_ops,
2341
	.rsk_prot		= &tcp_request_sock_ops,
2342
	.h.hashinfo		= &tcp_hashinfo,
2343
	.no_autobind		= true,
2344 2345 2346
#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
G
Glauber Costa 已提交
2347
#endif
2348
	.diag_destroy		= tcp_abort,
L
Linus Torvalds 已提交
2349
};
E
Eric Dumazet 已提交
2350
EXPORT_SYMBOL(tcp_prot);
L
Linus Torvalds 已提交
2351

2352 2353 2354 2355 2356 2357 2358 2359 2360
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);
}

2361 2362
static int __net_init tcp_sk_init(struct net *net)
{
2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377
	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;
	}
2378

2379
	net->ipv4.sysctl_tcp_ecn = 2;
2380 2381
	net->ipv4.sysctl_tcp_ecn_fallback = 1;

F
Fan Du 已提交
2382
	net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
2383
	net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
2384
	net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
2385

2386
	net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
2387
	net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
2388
	net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
2389

2390
	net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
2391
	net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
2392
	net->ipv4.sysctl_tcp_syncookies = 0;
2393
	net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH;
2394
	net->ipv4.sysctl_tcp_retries1 = TCP_RETR1;
2395
	net->ipv4.sysctl_tcp_retries2 = TCP_RETR2;
2396
	net->ipv4.sysctl_tcp_orphan_retries = 0;
2397

2398
	return 0;
2399 2400 2401 2402
fail:
	tcp_sk_exit(net);

	return res;
E
Eric W. Biederman 已提交
2403 2404 2405 2406 2407
}

static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
{
	inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET);
2408 2409 2410
}

static struct pernet_operations __net_initdata tcp_sk_ops = {
E
Eric W. Biederman 已提交
2411 2412 2413
       .init	   = tcp_sk_init,
       .exit	   = tcp_sk_exit,
       .exit_batch = tcp_sk_exit_batch,
2414 2415
};

2416
void __init tcp_v4_init(void)
L
Linus Torvalds 已提交
2417
{
2418
	inet_hashinfo_init(&tcp_hashinfo);
2419
	if (register_pernet_subsys(&tcp_sk_ops))
L
Linus Torvalds 已提交
2420 2421
		panic("Failed to create the TCP control socket.\n");
}