tcp_ipv4.c 63.1 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 &&
	    (twp == NULL || (sysctl_tcp_tw_reuse &&
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			     get_seconds() - tcptw->tw_ts_recent_stamp > 1))) {
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		tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2;
		if (tp->write_seq == 0)
			tp->write_seq = 1;
		tp->rx_opt.ts_recent	   = tcptw->tw_ts_recent;
		tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
		sock_hold(sktw);
		return 1;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(tcp_twsk_unique);

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/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
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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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	inet->inet_rcv_saddr = inet->inet_saddr;
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	if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
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		/* Reset inherited state */
		tp->rx_opt.ts_recent	   = 0;
		tp->rx_opt.ts_recent_stamp = 0;
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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;
	inet->inet_daddr = 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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	inet_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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/*
 * 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(net, &tcp_hashinfo, iph->daddr, th->dest,
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			iph->saddr, th->source, inet_iif(icmp_skb));
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	if (!sk) {
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		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
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		return;
	}
	if (sk->sk_state == TCP_TIME_WAIT) {
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		inet_twsk_put(inet_twsk(sk));
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		return;
	}

	bh_lock_sock(sk);
	/* If too many ICMPs get dropped on busy
	 * servers this needs to be solved differently.
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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);
	seq = ntohl(th->seq);
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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) {
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		struct request_sock *req, **prev;
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	case TCP_LISTEN:
		if (sock_owned_by_user(sk))
			goto out;

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

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

		/*
		 * Still in SYN_RECV, just remove it silently.
		 * There is no good way to pass the error to the newly
		 * created socket, and POSIX does not want network
		 * errors returned from accept().
		 */
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		inet_csk_reqsk_queue_drop(sk, req, prev);
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		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
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		goto out;

	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.
		 */
		if (fastopen && fastopen->sk == NULL)
			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(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;
588 589
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
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
628 629 630 631 632 633 634 635 636
	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.
		 */
637
		sk1 = __inet_lookup_listener(net,
638 639
					     &tcp_hashinfo, ip_hdr(skb)->saddr,
					     th->source, ip_hdr(skb)->daddr,
640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658
					     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;

		genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
		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;
	}

659 660 661 662 663 664 665 666 667
	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;

668
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
669 670
				     key, ip_hdr(skb)->saddr,
				     ip_hdr(skb)->daddr, &rep.th);
671 672
	}
#endif
673 674
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
675
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
L
Linus Torvalds 已提交
676
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
677
	arg.flags = (sk && inet_sk(sk)->transparent) ? 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
	arg.tos = ip_hdr(skb)->tos;
686 687
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
688 689
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
690

691 692
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
693 694 695 696 697 698 699 700

#ifdef CONFIG_TCP_MD5SIG
release_sk1:
	if (sk1) {
		rcu_read_unlock();
		sock_put(sk1);
	}
#endif
L
Linus Torvalds 已提交
701 702 703 704 705 706
}

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

707
static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
708
			    u32 win, u32 tsval, u32 tsecr, int oif,
709
			    struct tcp_md5sig_key *key,
710
			    int reply_flags, u8 tos)
L
Linus Torvalds 已提交
711
{
712
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
713 714
	struct {
		struct tcphdr th;
715
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
716
#ifdef CONFIG_TCP_MD5SIG
717
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
718 719
#endif
			];
L
Linus Torvalds 已提交
720 721
	} rep;
	struct ip_reply_arg arg;
E
Eric Dumazet 已提交
722
	struct net *net = dev_net(skb_dst(skb)->dev);
L
Linus Torvalds 已提交
723 724

	memset(&rep.th, 0, sizeof(struct tcphdr));
725
	memset(&arg, 0, sizeof(arg));
L
Linus Torvalds 已提交
726 727 728

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
729
	if (tsecr) {
730 731 732
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
733 734
		rep.opt[1] = htonl(tsval);
		rep.opt[2] = htonl(tsecr);
735
		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
736 737 738 739 740 741 742 743 744 745 746
	}

	/* 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);

747 748
#ifdef CONFIG_TCP_MD5SIG
	if (key) {
749
		int offset = (tsecr) ? 3 : 0;
750 751 752 753 754 755 756 757

		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;

758
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
759 760
				    key, ip_hdr(skb)->saddr,
				    ip_hdr(skb)->daddr, &rep.th);
761 762
	}
#endif
763
	arg.flags = reply_flags;
764 765
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
L
Linus Torvalds 已提交
766 767
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
768 769
	if (oif)
		arg.bound_dev_if = oif;
770
	arg.tos = tos;
771 772
	ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk),
			      skb, &TCP_SKB_CB(skb)->header.h4.opt,
773 774
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
775

776
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
L
Linus Torvalds 已提交
777 778 779 780
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
781
	struct inet_timewait_sock *tw = inet_twsk(sk);
782
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
783

784
	tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
785
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
786
			tcp_time_stamp + tcptw->tw_ts_offset,
787 788
			tcptw->tw_ts_recent,
			tw->tw_bound_dev_if,
789
			tcp_twsk_md5_key(tcptw),
790 791
			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
			tw->tw_tos
792
			);
L
Linus Torvalds 已提交
793

794
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
795 796
}

797
static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
798
				  struct request_sock *req)
L
Linus Torvalds 已提交
799
{
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,
			tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
806
			tcp_time_stamp,
807 808
			req->ts_recent,
			0,
E
Eric Dumazet 已提交
809 810
			tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
					  AF_INET),
811 812
			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
			ip_hdr(skb)->tos);
L
Linus Torvalds 已提交
813 814 815
}

/*
816
 *	Send a SYN-ACK after having received a SYN.
817
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
818 819
 *	socket.
 */
820
static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
821
			      struct flowi *fl,
822
			      struct request_sock *req,
823 824
			      u16 queue_mapping,
			      struct tcp_fastopen_cookie *foc)
L
Linus Torvalds 已提交
825
{
826
	const struct inet_request_sock *ireq = inet_rsk(req);
827
	struct flowi4 fl4;
L
Linus Torvalds 已提交
828
	int err = -1;
829
	struct sk_buff *skb;
L
Linus Torvalds 已提交
830 831

	/* First, grab a route. */
832
	if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
833
		return -1;
L
Linus Torvalds 已提交
834

835
	skb = tcp_make_synack(sk, dst, req, foc);
L
Linus Torvalds 已提交
836 837

	if (skb) {
838
		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
L
Linus Torvalds 已提交
839

840
		skb_set_queue_mapping(skb, queue_mapping);
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
/*
E
Eric Dumazet 已提交
859
 * Return true if a syncookie should be sent
860
 */
E
Eric Dumazet 已提交
861
bool tcp_syn_flood_action(struct sock *sk,
862 863
			 const struct sk_buff *skb,
			 const char *proto)
L
Linus Torvalds 已提交
864
{
865
	const char *msg = "Dropping request";
E
Eric Dumazet 已提交
866
	bool want_cookie = false;
867 868
	struct listen_sock *lopt;

869
#ifdef CONFIG_SYN_COOKIES
870
	if (sysctl_tcp_syncookies) {
871
		msg = "Sending cookies";
E
Eric Dumazet 已提交
872
		want_cookie = true;
873 874
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
	} else
875
#endif
876 877 878
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);

	lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
879
	if (!lopt->synflood_warned && sysctl_tcp_syncookies != 2) {
880
		lopt->synflood_warned = 1;
881
		pr_info("%s: Possible SYN flooding on port %d. %s.  Check SNMP counters.\n",
882 883 884
			proto, ntohs(tcp_hdr(skb)->dest), msg);
	}
	return want_cookie;
885
}
886
EXPORT_SYMBOL(tcp_syn_flood_action);
L
Linus Torvalds 已提交
887

888 889 890 891 892 893 894 895
#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.  */
E
Eric Dumazet 已提交
896 897 898
struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
					 const union tcp_md5_addr *addr,
					 int family)
899 900
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
901 902
	struct tcp_md5sig_key *key;
	unsigned int size = sizeof(struct in_addr);
903
	struct tcp_md5sig_info *md5sig;
904

905 906
	/* caller either holds rcu_read_lock() or socket lock */
	md5sig = rcu_dereference_check(tp->md5sig_info,
907 908
				       sock_owned_by_user(sk) ||
				       lockdep_is_held(&sk->sk_lock.slock));
909
	if (!md5sig)
910
		return NULL;
E
Eric Dumazet 已提交
911 912 913 914
#if IS_ENABLED(CONFIG_IPV6)
	if (family == AF_INET6)
		size = sizeof(struct in6_addr);
#endif
915
	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
E
Eric Dumazet 已提交
916 917 918 919
		if (key->family != family)
			continue;
		if (!memcmp(&key->addr, addr, size))
			return key;
920 921 922
	}
	return NULL;
}
E
Eric Dumazet 已提交
923
EXPORT_SYMBOL(tcp_md5_do_lookup);
924 925 926 927

struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
					 struct sock *addr_sk)
{
E
Eric Dumazet 已提交
928 929 930 931
	union tcp_md5_addr *addr;

	addr = (union tcp_md5_addr *)&inet_sk(addr_sk)->inet_daddr;
	return tcp_md5_do_lookup(sk, addr, AF_INET);
932 933 934
}
EXPORT_SYMBOL(tcp_v4_md5_lookup);

A
Adrian Bunk 已提交
935 936
static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
						      struct request_sock *req)
937
{
E
Eric Dumazet 已提交
938 939
	union tcp_md5_addr *addr;

940
	addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr;
E
Eric Dumazet 已提交
941
	return tcp_md5_do_lookup(sk, addr, AF_INET);
942 943 944
}

/* This can be called on a newly created socket, from other files */
E
Eric Dumazet 已提交
945 946
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
947 948
{
	/* Add Key to the list */
949
	struct tcp_md5sig_key *key;
950
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
951
	struct tcp_md5sig_info *md5sig;
952

953
	key = tcp_md5_do_lookup(sk, addr, family);
954 955
	if (key) {
		/* Pre-existing entry - just update that one. */
E
Eric Dumazet 已提交
956
		memcpy(key->key, newkey, newkeylen);
957
		key->keylen = newkeylen;
E
Eric Dumazet 已提交
958 959
		return 0;
	}
960

961 962
	md5sig = rcu_dereference_protected(tp->md5sig_info,
					   sock_owned_by_user(sk));
E
Eric Dumazet 已提交
963 964 965
	if (!md5sig) {
		md5sig = kmalloc(sizeof(*md5sig), gfp);
		if (!md5sig)
966 967
			return -ENOMEM;

E
Eric Dumazet 已提交
968 969
		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
		INIT_HLIST_HEAD(&md5sig->head);
970
		rcu_assign_pointer(tp->md5sig_info, md5sig);
E
Eric Dumazet 已提交
971
	}
972

973
	key = sock_kmalloc(sk, sizeof(*key), gfp);
E
Eric Dumazet 已提交
974 975
	if (!key)
		return -ENOMEM;
976
	if (!tcp_alloc_md5sig_pool()) {
977
		sock_kfree_s(sk, key, sizeof(*key));
E
Eric Dumazet 已提交
978
		return -ENOMEM;
979
	}
E
Eric Dumazet 已提交
980 981 982 983 984 985 986 987

	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);
988 989
	return 0;
}
E
Eric Dumazet 已提交
990
EXPORT_SYMBOL(tcp_md5_do_add);
991

E
Eric Dumazet 已提交
992
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
993
{
E
Eric Dumazet 已提交
994 995
	struct tcp_md5sig_key *key;

996
	key = tcp_md5_do_lookup(sk, addr, family);
E
Eric Dumazet 已提交
997 998 999
	if (!key)
		return -ENOENT;
	hlist_del_rcu(&key->node);
1000
	atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
1001 1002
	kfree_rcu(key, rcu);
	return 0;
1003
}
E
Eric Dumazet 已提交
1004
EXPORT_SYMBOL(tcp_md5_do_del);
1005

1006
static void tcp_clear_md5_list(struct sock *sk)
1007 1008
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1009
	struct tcp_md5sig_key *key;
1010
	struct hlist_node *n;
1011
	struct tcp_md5sig_info *md5sig;
1012

1013 1014
	md5sig = rcu_dereference_protected(tp->md5sig_info, 1);

1015
	hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
E
Eric Dumazet 已提交
1016
		hlist_del_rcu(&key->node);
1017
		atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
1018
		kfree_rcu(key, rcu);
1019 1020 1021
	}
}

1022 1023
static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
				 int optlen)
1024 1025 1026 1027 1028 1029 1030
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;

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

1031
	if (copy_from_user(&cmd, optval, sizeof(cmd)))
1032 1033 1034 1035 1036
		return -EFAULT;

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

1037
	if (!cmd.tcpm_keylen)
E
Eric Dumazet 已提交
1038 1039
		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
				      AF_INET);
1040 1041 1042 1043

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

E
Eric Dumazet 已提交
1044 1045 1046
	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);
1047 1048
}

1049 1050
static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
					__be32 daddr, __be32 saddr, int nbytes)
1051 1052
{
	struct tcp4_pseudohdr *bp;
1053
	struct scatterlist sg;
1054 1055 1056 1057

	bp = &hp->md5_blk.ip4;

	/*
1058
	 * 1. the TCP pseudo-header (in the order: source IP address,
1059 1060 1061 1062 1063 1064
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
1065
	bp->protocol = IPPROTO_TCP;
1066
	bp->len = cpu_to_be16(nbytes);
1067

1068 1069 1070 1071
	sg_init_one(&sg, bp, sizeof(*bp));
	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
}

E
Eric Dumazet 已提交
1072
static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1073
			       __be32 daddr, __be32 saddr, const struct tcphdr *th)
1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
{
	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))
1092 1093 1094 1095
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;
1096

1097 1098 1099 1100
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
1101
	return 1;
1102 1103
}

1104
int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1105 1106
			const struct sock *sk, const struct request_sock *req,
			const struct sk_buff *skb)
1107
{
1108 1109
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
E
Eric Dumazet 已提交
1110
	const struct tcphdr *th = tcp_hdr(skb);
1111 1112 1113
	__be32 saddr, daddr;

	if (sk) {
E
Eric Dumazet 已提交
1114 1115
		saddr = inet_sk(sk)->inet_saddr;
		daddr = inet_sk(sk)->inet_daddr;
1116
	} else if (req) {
1117 1118
		saddr = inet_rsk(req)->ir_loc_addr;
		daddr = inet_rsk(req)->ir_rmt_addr;
1119
	} else {
1120 1121 1122
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
1123
	}
1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151

	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;
1152
}
1153
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1154

1155 1156
static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
				      const struct sk_buff *skb)
1157 1158 1159 1160 1161 1162 1163 1164 1165
{
	/*
	 * 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.
	 */
1166
	const __u8 *hash_location = NULL;
1167
	struct tcp_md5sig_key *hash_expected;
1168
	const struct iphdr *iph = ip_hdr(skb);
1169
	const struct tcphdr *th = tcp_hdr(skb);
1170 1171 1172
	int genhash;
	unsigned char newhash[16];

E
Eric Dumazet 已提交
1173 1174
	hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
					  AF_INET);
1175
	hash_location = tcp_parse_md5sig_option(th);
1176 1177 1178

	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
E
Eric Dumazet 已提交
1179
		return false;
1180 1181

	if (hash_expected && !hash_location) {
1182
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
E
Eric Dumazet 已提交
1183
		return true;
1184 1185 1186
	}

	if (!hash_expected && hash_location) {
1187
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
E
Eric Dumazet 已提交
1188
		return true;
1189 1190 1191 1192 1193
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
1194 1195 1196
	genhash = tcp_v4_md5_hash_skb(newhash,
				      hash_expected,
				      NULL, NULL, skb);
1197 1198

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1199 1200 1201 1202 1203
		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
1204
		return true;
1205
	}
E
Eric Dumazet 已提交
1206
	return false;
1207 1208
}

1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219
static bool tcp_v4_inbound_md5_hash(struct sock *sk, const struct sk_buff *skb)
{
	bool ret;

	rcu_read_lock();
	ret = __tcp_v4_inbound_md5_hash(sk, skb);
	rcu_read_unlock();

	return ret;
}

1220 1221
#endif

1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232
static void tcp_v4_init_req(struct request_sock *req, struct sock *sk,
			    struct sk_buff *skb)
{
	struct inet_request_sock *ireq = inet_rsk(req);

	ireq->ir_loc_addr = ip_hdr(skb)->daddr;
	ireq->ir_rmt_addr = ip_hdr(skb)->saddr;
	ireq->no_srccheck = inet_sk(sk)->transparent;
	ireq->opt = tcp_v4_save_options(skb);
}

1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,
					  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;
}

1249
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1250
	.family		=	PF_INET,
1251
	.obj_size	=	sizeof(struct tcp_request_sock),
1252
	.rtx_syn_ack	=	tcp_rtx_synack,
1253 1254
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1255
	.send_reset	=	tcp_v4_send_reset,
S
stephen hemminger 已提交
1256
	.syn_ack_timeout =	tcp_syn_ack_timeout,
L
Linus Torvalds 已提交
1257 1258
};

1259
static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1260
	.mss_clamp	=	TCP_MSS_DEFAULT,
1261
#ifdef CONFIG_TCP_MD5SIG
1262
	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
1263
	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1264
#endif
1265
	.init_req	=	tcp_v4_init_req,
1266 1267 1268
#ifdef CONFIG_SYN_COOKIES
	.cookie_init_seq =	cookie_v4_init_sequence,
#endif
1269
	.route_req	=	tcp_v4_route_req,
1270
	.init_seq	=	tcp_v4_init_sequence,
1271
	.send_synack	=	tcp_v4_send_synack,
1272
	.queue_hash_add =	inet_csk_reqsk_queue_hash_add,
1273
};
1274

L
Linus Torvalds 已提交
1275 1276 1277
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
1278
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
L
Linus Torvalds 已提交
1279 1280
		goto drop;

O
Octavian Purdila 已提交
1281 1282
	return tcp_conn_request(&tcp_request_sock_ops,
				&tcp_request_sock_ipv4_ops, sk, skb);
L
Linus Torvalds 已提交
1283 1284

drop:
1285
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1286 1287
	return 0;
}
E
Eric Dumazet 已提交
1288
EXPORT_SYMBOL(tcp_v4_conn_request);
L
Linus Torvalds 已提交
1289 1290 1291 1292 1293 1294 1295


/*
 * The three way handshake has completed - we got a valid synack -
 * now create the new socket.
 */
struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
1296
				  struct request_sock *req,
L
Linus Torvalds 已提交
1297 1298
				  struct dst_entry *dst)
{
1299
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1300 1301 1302
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1303 1304 1305
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
1306
	struct ip_options_rcu *inet_opt;
L
Linus Torvalds 已提交
1307 1308 1309 1310 1311 1312

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
1313
		goto exit_nonewsk;
L
Linus Torvalds 已提交
1314

1315
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1316
	inet_sk_rx_dst_set(newsk, skb);
L
Linus Torvalds 已提交
1317 1318 1319

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1320
	ireq		      = inet_rsk(req);
1321 1322 1323
	newinet->inet_daddr   = ireq->ir_rmt_addr;
	newinet->inet_rcv_saddr = ireq->ir_loc_addr;
	newinet->inet_saddr	      = ireq->ir_loc_addr;
1324 1325
	inet_opt	      = ireq->opt;
	rcu_assign_pointer(newinet->inet_opt, inet_opt);
1326
	ireq->opt	      = NULL;
1327
	newinet->mc_index     = inet_iif(skb);
1328
	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
1329
	newinet->rcv_tos      = ip_hdr(skb)->tos;
1330
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1331
	inet_set_txhash(newsk);
1332 1333
	if (inet_opt)
		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
E
Eric Dumazet 已提交
1334
	newinet->inet_id = newtp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
1335

E
Eric Dumazet 已提交
1336 1337 1338 1339 1340 1341 1342
	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() */
	}
1343 1344
	sk_setup_caps(newsk, dst);

1345 1346
	tcp_ca_openreq_child(newsk, dst);

L
Linus Torvalds 已提交
1347
	tcp_sync_mss(newsk, dst_mtu(dst));
1348
	newtp->advmss = dst_metric_advmss(dst);
1349 1350 1351 1352
	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
1353 1354
	tcp_initialize_rcv_mss(newsk);

1355 1356
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
E
Eric Dumazet 已提交
1357 1358
	key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
				AF_INET);
E
Eric Dumazet 已提交
1359
	if (key != NULL) {
1360 1361 1362 1363 1364 1365
		/*
		 * 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
1366 1367
		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
1368
		sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1369 1370 1371
	}
#endif

1372 1373
	if (__inet_inherit_port(sk, newsk) < 0)
		goto put_and_exit;
1374
	__inet_hash_nolisten(newsk, NULL);
L
Linus Torvalds 已提交
1375 1376 1377 1378

	return newsk;

exit_overflow:
1379
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1380 1381
exit_nonewsk:
	dst_release(dst);
L
Linus Torvalds 已提交
1382
exit:
1383
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1384
	return NULL;
1385
put_and_exit:
1386 1387
	inet_csk_prepare_forced_close(newsk);
	tcp_done(newsk);
1388
	goto exit;
L
Linus Torvalds 已提交
1389
}
E
Eric Dumazet 已提交
1390
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
L
Linus Torvalds 已提交
1391 1392 1393

static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
{
1394
	struct tcphdr *th = tcp_hdr(skb);
1395
	const struct iphdr *iph = ip_hdr(skb);
L
Linus Torvalds 已提交
1396
	struct sock *nsk;
1397
	struct request_sock **prev;
L
Linus Torvalds 已提交
1398
	/* Find possible connection requests. */
1399 1400
	struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
						       iph->saddr, iph->daddr);
L
Linus Torvalds 已提交
1401
	if (req)
1402
		return tcp_check_req(sk, skb, req, prev, false);
L
Linus Torvalds 已提交
1403

1404
	nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1405
			th->source, iph->daddr, th->dest, inet_iif(skb));
L
Linus Torvalds 已提交
1406 1407 1408 1409 1410 1411

	if (nsk) {
		if (nsk->sk_state != TCP_TIME_WAIT) {
			bh_lock_sock(nsk);
			return nsk;
		}
1412
		inet_twsk_put(inet_twsk(nsk));
L
Linus Torvalds 已提交
1413 1414 1415 1416
		return NULL;
	}

#ifdef CONFIG_SYN_COOKIES
1417
	if (!th->syn)
C
Cong Wang 已提交
1418
		sk = cookie_v4_check(sk, skb);
L
Linus Torvalds 已提交
1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432
#endif
	return sk;
}

/* The socket must have it's spinlock held when we get
 * here.
 *
 * We have a potential double-lock case here, so even when
 * doing backlog processing we use the BH locking scheme.
 * This is because we cannot sleep with the original spinlock
 * held.
 */
int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
{
1433 1434
	struct sock *rsk;

L
Linus Torvalds 已提交
1435
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1436 1437
		struct dst_entry *dst = sk->sk_rx_dst;

1438
		sock_rps_save_rxhash(sk, skb);
1439
		sk_mark_napi_id(sk, skb);
1440
		if (dst) {
E
Eric Dumazet 已提交
1441 1442
			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
			    dst->ops->check(dst, 0) == NULL) {
1443 1444 1445 1446
				dst_release(dst);
				sk->sk_rx_dst = NULL;
			}
		}
1447
		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
L
Linus Torvalds 已提交
1448 1449 1450
		return 0;
	}

1451
	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
L
Linus Torvalds 已提交
1452 1453 1454 1455 1456 1457 1458 1459
		goto csum_err;

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

		if (nsk != sk) {
1460
			sock_rps_save_rxhash(nsk, skb);
1461
			sk_mark_napi_id(sk, skb);
1462 1463
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1464
				goto reset;
1465
			}
L
Linus Torvalds 已提交
1466 1467
			return 0;
		}
1468
	} else
1469
		sock_rps_save_rxhash(sk, skb);
1470

1471
	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1472
		rsk = sk;
L
Linus Torvalds 已提交
1473
		goto reset;
1474
	}
L
Linus Torvalds 已提交
1475 1476 1477
	return 0;

reset:
1478
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1479 1480 1481 1482 1483 1484 1485 1486 1487 1488
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:
1489
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1490
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1491 1492
	goto discard;
}
E
Eric Dumazet 已提交
1493
EXPORT_SYMBOL(tcp_v4_do_rcv);
L
Linus Torvalds 已提交
1494

1495
void tcp_v4_early_demux(struct sk_buff *skb)
D
David S. Miller 已提交
1496 1497 1498 1499 1500 1501
{
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct sock *sk;

	if (skb->pkt_type != PACKET_HOST)
1502
		return;
D
David S. Miller 已提交
1503

1504
	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1505
		return;
D
David S. Miller 已提交
1506 1507

	iph = ip_hdr(skb);
1508
	th = tcp_hdr(skb);
D
David S. Miller 已提交
1509 1510

	if (th->doff < sizeof(struct tcphdr) / 4)
1511
		return;
D
David S. Miller 已提交
1512

1513
	sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
D
David S. Miller 已提交
1514
				       iph->saddr, th->source,
1515
				       iph->daddr, ntohs(th->dest),
E
Eric Dumazet 已提交
1516
				       skb->skb_iif);
D
David S. Miller 已提交
1517 1518 1519 1520 1521
	if (sk) {
		skb->sk = sk;
		skb->destructor = sock_edemux;
		if (sk->sk_state != TCP_TIME_WAIT) {
			struct dst_entry *dst = sk->sk_rx_dst;
E
Eric Dumazet 已提交
1522

D
David S. Miller 已提交
1523 1524
			if (dst)
				dst = dst_check(dst, 0);
1525
			if (dst &&
E
Eric Dumazet 已提交
1526
			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1527
				skb_dst_set_noref(skb, dst);
D
David S. Miller 已提交
1528 1529 1530 1531
		}
	}
}

E
Eric Dumazet 已提交
1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549
/* 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;

1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
	/* 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
1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586
	__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
1587 1588 1589 1590 1591 1592
/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
1593
	const struct iphdr *iph;
1594
	const struct tcphdr *th;
L
Linus Torvalds 已提交
1595 1596
	struct sock *sk;
	int ret;
1597
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
1598 1599 1600 1601 1602

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

	/* Count it even if it's bad */
1603
	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
L
Linus Torvalds 已提交
1604 1605 1606 1607

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

1608
	th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1609 1610 1611 1612 1613 1614 1615 1616

	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
1617
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1618
	 * So, we defer the checks. */
1619 1620

	if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1621
		goto csum_error;
L
Linus Torvalds 已提交
1622

1623
	th = tcp_hdr(skb);
1624
	iph = ip_hdr(skb);
1625 1626 1627 1628 1629 1630 1631
	/* 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
1632 1633 1634 1635
	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);
1636
	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1637
	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1638
	TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
L
Linus Torvalds 已提交
1639 1640
	TCP_SKB_CB(skb)->sacked	 = 0;

1641
	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
L
Linus Torvalds 已提交
1642 1643 1644
	if (!sk)
		goto no_tcp_socket;

E
Eric Dumazet 已提交
1645 1646 1647 1648
process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

1649 1650
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1651
		goto discard_and_relse;
1652
	}
1653

L
Linus Torvalds 已提交
1654 1655
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667

#ifdef CONFIG_TCP_MD5SIG
	/*
	 * We really want to reject the packet as early as possible
	 * if:
	 *  o We're expecting an MD5'd packet and this is no MD5 tcp option
	 *  o There is an MD5 option and we're not expecting one
	 */
	if (tcp_v4_inbound_md5_hash(sk, skb))
		goto discard_and_relse;
#endif

1668
	nf_reset(skb);
L
Linus Torvalds 已提交
1669

1670
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1671 1672
		goto discard_and_relse;

E
Eric Dumazet 已提交
1673
	sk_incoming_cpu_update(sk);
L
Linus Torvalds 已提交
1674 1675
	skb->dev = NULL;

1676
	bh_lock_sock_nested(sk);
L
Linus Torvalds 已提交
1677 1678
	ret = 0;
	if (!sock_owned_by_user(sk)) {
D
Dan Williams 已提交
1679
		if (!tcp_prequeue(sk, skb))
L
Linus Torvalds 已提交
1680
			ret = tcp_v4_do_rcv(sk, skb);
1681 1682
	} else if (unlikely(sk_add_backlog(sk, skb,
					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
Z
Zhu Yi 已提交
1683
		bh_unlock_sock(sk);
1684
		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
Z
Zhu Yi 已提交
1685 1686
		goto discard_and_relse;
	}
L
Linus Torvalds 已提交
1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697
	bh_unlock_sock(sk);

	sock_put(sk);

	return ret;

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

	if (skb->len < (th->doff << 2) || tcp_checksum_complete(skb)) {
1698 1699
csum_error:
		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
L
Linus Torvalds 已提交
1700
bad_packet:
1701
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1702
	} else {
1703
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1704 1705 1706 1707 1708
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
1709
	return 0;
L
Linus Torvalds 已提交
1710 1711 1712 1713 1714 1715 1716

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1717
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1718 1719 1720
		goto discard_it;
	}

1721
	if (skb->len < (th->doff << 2)) {
1722
		inet_twsk_put(inet_twsk(sk));
1723 1724 1725 1726 1727
		goto bad_packet;
	}
	if (tcp_checksum_complete(skb)) {
		inet_twsk_put(inet_twsk(sk));
		goto csum_error;
L
Linus Torvalds 已提交
1728
	}
1729
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1730
	case TCP_TW_SYN: {
1731
		struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1732
							&tcp_hashinfo,
1733
							iph->saddr, th->source,
1734
							iph->daddr, th->dest,
1735
							inet_iif(skb));
L
Linus Torvalds 已提交
1736
		if (sk2) {
1737 1738
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753
			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;
}

1754 1755 1756 1757 1758
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
1759

1760
void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
E
Eric Dumazet 已提交
1761 1762 1763
{
	struct dst_entry *dst = skb_dst(skb);

1764 1765 1766 1767 1768
	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
1769
}
1770
EXPORT_SYMBOL(inet_sk_rx_dst_set);
E
Eric Dumazet 已提交
1771

1772
const struct inet_connection_sock_af_ops ipv4_specific = {
1773 1774 1775
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
E
Eric Dumazet 已提交
1776
	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1777 1778 1779 1780 1781 1782 1783
	.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),
1784
	.bind_conflict	   = inet_csk_bind_conflict,
1785
#ifdef CONFIG_COMPAT
1786 1787
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1788
#endif
1789
	.mtu_reduced	   = tcp_v4_mtu_reduced,
L
Linus Torvalds 已提交
1790
};
E
Eric Dumazet 已提交
1791
EXPORT_SYMBOL(ipv4_specific);
L
Linus Torvalds 已提交
1792

1793
#ifdef CONFIG_TCP_MD5SIG
1794
static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1795
	.md5_lookup		= tcp_v4_md5_lookup,
1796
	.calc_md5_hash		= tcp_v4_md5_hash_skb,
1797 1798
	.md5_parse		= tcp_v4_parse_md5_keys,
};
1799
#endif
1800

L
Linus Torvalds 已提交
1801 1802 1803 1804 1805
/* 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)
{
1806
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1807

1808
	tcp_init_sock(sk);
L
Linus Torvalds 已提交
1809

1810
	icsk->icsk_af_ops = &ipv4_specific;
1811

1812
#ifdef CONFIG_TCP_MD5SIG
1813
	tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1814
#endif
L
Linus Torvalds 已提交
1815 1816 1817 1818

	return 0;
}

1819
void tcp_v4_destroy_sock(struct sock *sk)
L
Linus Torvalds 已提交
1820 1821 1822 1823 1824
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1825
	tcp_cleanup_congestion_control(sk);
1826

L
Linus Torvalds 已提交
1827
	/* Cleanup up the write buffer. */
1828
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
1829 1830

	/* Cleans up our, hopefully empty, out_of_order_queue. */
1831
	__skb_queue_purge(&tp->out_of_order_queue);
L
Linus Torvalds 已提交
1832

1833 1834 1835
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
E
Eric Dumazet 已提交
1836
		tcp_clear_md5_list(sk);
1837
		kfree_rcu(tp->md5sig_info, rcu);
1838 1839 1840
		tp->md5sig_info = NULL;
	}
#endif
C
Chris Leech 已提交
1841

L
Linus Torvalds 已提交
1842 1843 1844 1845
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1846
	if (inet_csk(sk)->icsk_bind_hash)
1847
		inet_put_port(sk);
L
Linus Torvalds 已提交
1848

1849
	BUG_ON(tp->fastopen_rsk != NULL);
1850

1851 1852 1853
	/* If socket is aborted during connect operation */
	tcp_free_fastopen_req(tp);

1854
	sk_sockets_allocated_dec(sk);
G
Glauber Costa 已提交
1855
	sock_release_memcg(sk);
L
Linus Torvalds 已提交
1856 1857 1858 1859 1860 1861
}
EXPORT_SYMBOL(tcp_v4_destroy_sock);

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

1862 1863 1864 1865 1866
/*
 * 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
1867 1868
static void *listening_get_next(struct seq_file *seq, void *cur)
{
1869
	struct inet_connection_sock *icsk;
1870
	struct hlist_nulls_node *node;
L
Linus Torvalds 已提交
1871
	struct sock *sk = cur;
1872
	struct inet_listen_hashbucket *ilb;
J
Jianjun Kong 已提交
1873
	struct tcp_iter_state *st = seq->private;
1874
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1875 1876

	if (!sk) {
1877
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
1878
		spin_lock_bh(&ilb->lock);
1879
		sk = sk_nulls_head(&ilb->head);
1880
		st->offset = 0;
L
Linus Torvalds 已提交
1881 1882
		goto get_sk;
	}
1883
	ilb = &tcp_hashinfo.listening_hash[st->bucket];
L
Linus Torvalds 已提交
1884
	++st->num;
1885
	++st->offset;
L
Linus Torvalds 已提交
1886 1887

	if (st->state == TCP_SEQ_STATE_OPENREQ) {
1888
		struct request_sock *req = cur;
L
Linus Torvalds 已提交
1889

1890
		icsk = inet_csk(st->syn_wait_sk);
L
Linus Torvalds 已提交
1891 1892 1893
		req = req->dl_next;
		while (1) {
			while (req) {
1894
				if (req->rsk_ops->family == st->family) {
L
Linus Torvalds 已提交
1895 1896 1897 1898 1899
					cur = req;
					goto out;
				}
				req = req->dl_next;
			}
1900
			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
L
Linus Torvalds 已提交
1901 1902
				break;
get_req:
1903
			req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
L
Linus Torvalds 已提交
1904
		}
E
Eric Dumazet 已提交
1905
		sk	  = sk_nulls_next(st->syn_wait_sk);
L
Linus Torvalds 已提交
1906
		st->state = TCP_SEQ_STATE_LISTENING;
1907
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
1908
	} else {
1909
		icsk = inet_csk(sk);
1910 1911
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue))
L
Linus Torvalds 已提交
1912
			goto start_req;
1913
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
E
Eric Dumazet 已提交
1914
		sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1915 1916
	}
get_sk:
1917
	sk_nulls_for_each_from(sk, node) {
1918 1919 1920
		if (!net_eq(sock_net(sk), net))
			continue;
		if (sk->sk_family == st->family) {
L
Linus Torvalds 已提交
1921 1922 1923
			cur = sk;
			goto out;
		}
1924
		icsk = inet_csk(sk);
1925 1926
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
L
Linus Torvalds 已提交
1927 1928 1929 1930 1931 1932 1933
start_req:
			st->uid		= sock_i_uid(sk);
			st->syn_wait_sk = sk;
			st->state	= TCP_SEQ_STATE_OPENREQ;
			st->sbucket	= 0;
			goto get_req;
		}
1934
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
1935
	}
1936
	spin_unlock_bh(&ilb->lock);
1937
	st->offset = 0;
1938
	if (++st->bucket < INET_LHTABLE_SIZE) {
1939 1940
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
		spin_lock_bh(&ilb->lock);
1941
		sk = sk_nulls_head(&ilb->head);
L
Linus Torvalds 已提交
1942 1943 1944 1945 1946 1947 1948 1949 1950
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
1951 1952 1953 1954 1955 1956
	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
1957 1958 1959 1960 1961 1962 1963 1964

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

E
Eric Dumazet 已提交
1965
static inline bool empty_bucket(const struct tcp_iter_state *st)
1966
{
E
Eric Dumazet 已提交
1967
	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1968 1969
}

1970 1971 1972 1973
/*
 * 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
1974 1975
static void *established_get_first(struct seq_file *seq)
{
J
Jianjun Kong 已提交
1976
	struct tcp_iter_state *st = seq->private;
1977
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1978 1979
	void *rc = NULL;

1980 1981
	st->offset = 0;
	for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
L
Linus Torvalds 已提交
1982
		struct sock *sk;
1983
		struct hlist_nulls_node *node;
1984
		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
L
Linus Torvalds 已提交
1985

1986 1987 1988 1989
		/* Lockless fast path for the common case of empty buckets */
		if (empty_bucket(st))
			continue;

1990
		spin_lock_bh(lock);
1991
		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1992
			if (sk->sk_family != st->family ||
1993
			    !net_eq(sock_net(sk), net)) {
L
Linus Torvalds 已提交
1994 1995 1996 1997 1998
				continue;
			}
			rc = sk;
			goto out;
		}
1999
		spin_unlock_bh(lock);
L
Linus Torvalds 已提交
2000 2001 2002 2003 2004 2005 2006 2007
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
2008
	struct hlist_nulls_node *node;
J
Jianjun Kong 已提交
2009
	struct tcp_iter_state *st = seq->private;
2010
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2011 2012

	++st->num;
2013
	++st->offset;
L
Linus Torvalds 已提交
2014

E
Eric Dumazet 已提交
2015
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
2016

2017
	sk_nulls_for_each_from(sk, node) {
2018
		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
E
Eric Dumazet 已提交
2019
			return sk;
L
Linus Torvalds 已提交
2020 2021
	}

E
Eric Dumazet 已提交
2022 2023 2024
	spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
	++st->bucket;
	return established_get_first(seq);
L
Linus Torvalds 已提交
2025 2026 2027 2028
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
2029 2030 2031 2032 2033
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	rc = established_get_first(seq);
L
Linus Torvalds 已提交
2034 2035 2036 2037

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
2038
	}
L
Linus Torvalds 已提交
2039 2040 2041 2042 2043 2044
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
J
Jianjun Kong 已提交
2045
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057

	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;
}

2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076
static void *tcp_seek_last_pos(struct seq_file *seq)
{
	struct tcp_iter_state *st = seq->private;
	int offset = st->offset;
	int orig_num = st->num;
	void *rc = NULL;

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		if (st->bucket >= INET_LHTABLE_SIZE)
			break;
		st->state = TCP_SEQ_STATE_LISTENING;
		rc = listening_get_next(seq, NULL);
		while (offset-- && rc)
			rc = listening_get_next(seq, rc);
		if (rc)
			break;
		st->bucket = 0;
E
Eric Dumazet 已提交
2077
		st->state = TCP_SEQ_STATE_ESTABLISHED;
2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091
		/* 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
2092 2093
static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
J
Jianjun Kong 已提交
2094
	struct tcp_iter_state *st = seq->private;
2095 2096 2097 2098 2099 2100 2101 2102
	void *rc;

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

L
Linus Torvalds 已提交
2103 2104
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
2105 2106 2107 2108 2109 2110 2111
	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
2112 2113 2114 2115
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2116
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129
	void *rc = NULL;

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

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
	case TCP_SEQ_STATE_LISTENING:
		rc = listening_get_next(seq, v);
		if (!rc) {
			st->state = TCP_SEQ_STATE_ESTABLISHED;
2130 2131
			st->bucket = 0;
			st->offset = 0;
L
Linus Torvalds 已提交
2132 2133 2134 2135 2136 2137 2138 2139 2140
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
2141
	st->last_pos = *pos;
L
Linus Torvalds 已提交
2142 2143 2144 2145 2146
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2147
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2148 2149 2150 2151

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
		if (v) {
2152 2153
			struct inet_connection_sock *icsk = inet_csk(st->syn_wait_sk);
			read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
2154 2155 2156
		}
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2157
			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
L
Linus Torvalds 已提交
2158 2159 2160
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2161
			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2162 2163 2164 2165
		break;
	}
}

2166
int tcp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2167
{
A
Al Viro 已提交
2168
	struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
L
Linus Torvalds 已提交
2169
	struct tcp_iter_state *s;
2170
	int err;
L
Linus Torvalds 已提交
2171

2172 2173 2174 2175
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			  sizeof(struct tcp_iter_state));
	if (err < 0)
		return err;
2176

2177
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2178
	s->family		= afinfo->family;
S
stephen hemminger 已提交
2179
	s->last_pos		= 0;
2180 2181
	return 0;
}
2182
EXPORT_SYMBOL(tcp_seq_open);
2183

2184
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2185 2186 2187 2188
{
	int rc = 0;
	struct proc_dir_entry *p;

2189 2190 2191 2192
	afinfo->seq_ops.start		= tcp_seq_start;
	afinfo->seq_ops.next		= tcp_seq_next;
	afinfo->seq_ops.stop		= tcp_seq_stop;

2193
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2194
			     afinfo->seq_fops, afinfo);
2195
	if (!p)
L
Linus Torvalds 已提交
2196 2197 2198
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2199
EXPORT_SYMBOL(tcp_proc_register);
L
Linus Torvalds 已提交
2200

2201
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2202
{
2203
	remove_proc_entry(afinfo->name, net->proc_net);
L
Linus Torvalds 已提交
2204
}
E
Eric Dumazet 已提交
2205
EXPORT_SYMBOL(tcp_proc_unregister);
L
Linus Torvalds 已提交
2206

2207
static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2208
			 struct seq_file *f, int i, kuid_t uid)
L
Linus Torvalds 已提交
2209
{
2210
	const struct inet_request_sock *ireq = inet_rsk(req);
2211
	long delta = req->expires - jiffies;
L
Linus Torvalds 已提交
2212

2213
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2214
		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
L
Linus Torvalds 已提交
2215
		i,
2216
		ireq->ir_loc_addr,
E
Eric Dumazet 已提交
2217
		ntohs(inet_sk(sk)->inet_sport),
2218 2219
		ireq->ir_rmt_addr,
		ntohs(ireq->ir_rmt_port),
L
Linus Torvalds 已提交
2220 2221 2222
		TCP_SYN_RECV,
		0, 0, /* could print option size, but that is af dependent. */
		1,    /* timers active (only the expire timer) */
2223
		jiffies_delta_to_clock_t(delta),
2224
		req->num_timeout,
2225
		from_kuid_munged(seq_user_ns(f), uid),
L
Linus Torvalds 已提交
2226 2227 2228
		0,  /* non standard timer */
		0, /* open_requests have no inode */
		atomic_read(&sk->sk_refcnt),
2229
		req);
L
Linus Torvalds 已提交
2230 2231
}

2232
static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
L
Linus Torvalds 已提交
2233 2234 2235
{
	int timer_active;
	unsigned long timer_expires;
2236
	const struct tcp_sock *tp = tcp_sk(sk);
2237
	const struct inet_connection_sock *icsk = inet_csk(sk);
2238
	const struct inet_sock *inet = inet_sk(sk);
2239
	struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
E
Eric Dumazet 已提交
2240 2241 2242 2243
	__be32 dest = inet->inet_daddr;
	__be32 src = inet->inet_rcv_saddr;
	__u16 destp = ntohs(inet->inet_dport);
	__u16 srcp = ntohs(inet->inet_sport);
2244
	int rx_queue;
L
Linus Torvalds 已提交
2245

N
Nandita Dukkipati 已提交
2246 2247 2248
	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
2249
		timer_active	= 1;
2250 2251
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2252
		timer_active	= 4;
2253
		timer_expires	= icsk->icsk_timeout;
2254
	} else if (timer_pending(&sk->sk_timer)) {
L
Linus Torvalds 已提交
2255
		timer_active	= 2;
2256
		timer_expires	= sk->sk_timer.expires;
L
Linus Torvalds 已提交
2257 2258 2259 2260 2261
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

2262 2263 2264 2265 2266 2267 2268 2269
	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);

2270
	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2271
			"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2272
		i, src, srcp, dest, destp, sk->sk_state,
2273
		tp->write_seq - tp->snd_una,
2274
		rx_queue,
L
Linus Torvalds 已提交
2275
		timer_active,
2276
		jiffies_delta_to_clock_t(timer_expires - jiffies),
2277
		icsk->icsk_retransmits,
2278
		from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2279
		icsk->icsk_probes_out,
2280 2281
		sock_i_ino(sk),
		atomic_read(&sk->sk_refcnt), sk,
2282 2283
		jiffies_to_clock_t(icsk->icsk_rto),
		jiffies_to_clock_t(icsk->icsk_ack.ato),
2284
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2285
		tp->snd_cwnd,
2286 2287
		sk->sk_state == TCP_LISTEN ?
		    (fastopenq ? fastopenq->max_qlen : 0) :
2288
		    (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
L
Linus Torvalds 已提交
2289 2290
}

2291
static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2292
			       struct seq_file *f, int i)
L
Linus Torvalds 已提交
2293
{
2294
	__be32 dest, src;
L
Linus Torvalds 已提交
2295
	__u16 destp, srcp;
2296
	s32 delta = tw->tw_ttd - inet_tw_time_stamp();
L
Linus Torvalds 已提交
2297 2298 2299 2300 2301 2302

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

2303
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2304
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
L
Linus Torvalds 已提交
2305
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2306
		3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2307
		atomic_read(&tw->tw_refcnt), tw);
L
Linus Torvalds 已提交
2308 2309 2310 2311 2312 2313
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2314
	struct tcp_iter_state *st;
E
Eric Dumazet 已提交
2315
	struct sock *sk = v;
L
Linus Torvalds 已提交
2316

2317
	seq_setwidth(seq, TMPSZ - 1);
L
Linus Torvalds 已提交
2318
	if (v == SEQ_START_TOKEN) {
2319
		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
L
Linus Torvalds 已提交
2320 2321 2322 2323 2324 2325 2326 2327 2328
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
			   "inode");
		goto out;
	}
	st = seq->private;

	switch (st->state) {
	case TCP_SEQ_STATE_LISTENING:
	case TCP_SEQ_STATE_ESTABLISHED:
E
Eric Dumazet 已提交
2329
		if (sk->sk_state == TCP_TIME_WAIT)
2330
			get_timewait4_sock(v, seq, st->num);
E
Eric Dumazet 已提交
2331
		else
2332
			get_tcp4_sock(v, seq, st->num);
L
Linus Torvalds 已提交
2333 2334
		break;
	case TCP_SEQ_STATE_OPENREQ:
2335
		get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid);
L
Linus Torvalds 已提交
2336 2337 2338
		break;
	}
out:
2339
	seq_pad(seq, '\n');
L
Linus Torvalds 已提交
2340 2341 2342
	return 0;
}

2343 2344 2345 2346 2347 2348 2349 2350
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
2351 2352 2353
static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.name		= "tcp",
	.family		= AF_INET,
2354
	.seq_fops	= &tcp_afinfo_seq_fops,
2355 2356 2357
	.seq_ops	= {
		.show		= tcp4_seq_show,
	},
L
Linus Torvalds 已提交
2358 2359
};

2360
static int __net_init tcp4_proc_init_net(struct net *net)
2361 2362 2363 2364
{
	return tcp_proc_register(net, &tcp4_seq_afinfo);
}

2365
static void __net_exit tcp4_proc_exit_net(struct net *net)
2366 2367 2368 2369 2370 2371 2372 2373 2374
{
	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
2375 2376
int __init tcp4_proc_init(void)
{
2377
	return register_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2378 2379 2380 2381
}

void tcp4_proc_exit(void)
{
2382
	unregister_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2383 2384 2385 2386 2387 2388 2389 2390 2391
}
#endif /* CONFIG_PROC_FS */

struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2392
	.accept			= inet_csk_accept,
L
Linus Torvalds 已提交
2393 2394 2395 2396 2397 2398 2399
	.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,
2400 2401
	.sendmsg		= tcp_sendmsg,
	.sendpage		= tcp_sendpage,
L
Linus Torvalds 已提交
2402
	.backlog_rcv		= tcp_v4_do_rcv,
E
Eric Dumazet 已提交
2403
	.release_cb		= tcp_release_cb,
2404 2405 2406
	.hash			= inet_hash,
	.unhash			= inet_unhash,
	.get_port		= inet_csk_get_port,
L
Linus Torvalds 已提交
2407
	.enter_memory_pressure	= tcp_enter_memory_pressure,
2408
	.stream_memory_free	= tcp_stream_memory_free,
L
Linus Torvalds 已提交
2409
	.sockets_allocated	= &tcp_sockets_allocated,
2410
	.orphan_count		= &tcp_orphan_count,
L
Linus Torvalds 已提交
2411 2412
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
2413
	.sysctl_mem		= sysctl_tcp_mem,
L
Linus Torvalds 已提交
2414 2415 2416 2417
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2418
	.slab_flags		= SLAB_DESTROY_BY_RCU,
2419
	.twsk_prot		= &tcp_timewait_sock_ops,
2420
	.rsk_prot		= &tcp_request_sock_ops,
2421
	.h.hashinfo		= &tcp_hashinfo,
2422
	.no_autobind		= true,
2423 2424 2425 2426
#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
A
Andrew Morton 已提交
2427
#ifdef CONFIG_MEMCG_KMEM
G
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	.init_cgroup		= tcp_init_cgroup,
	.destroy_cgroup		= tcp_destroy_cgroup,
	.proto_cgroup		= tcp_proto_cgroup,
#endif
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};
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EXPORT_SYMBOL(tcp_prot);
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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);
}

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static int __net_init tcp_sk_init(struct net *net)
{
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	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;
	}
2461
	net->ipv4.sysctl_tcp_ecn = 2;
2462
	return 0;
2463

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fail:
	tcp_sk_exit(net);

	return res;
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}

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

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

2481
void __init tcp_v4_init(void)
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{
2483
	inet_hashinfo_init(&tcp_hashinfo);
2484
	if (register_pernet_subsys(&tcp_sk_ops))
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		panic("Failed to create the TCP control socket.\n");
}