tcp_ipv4.c 62.3 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_set_txhash(sk);

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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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	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;

E
Eric Dumazet 已提交
601
	if (skb_rtable(skb)->rt_type != RTN_LOCAL)
L
Linus Torvalds 已提交
602 603 604
		return;

	/* Swap the send and the receive. */
605 606 607 608 609
	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
610 611

	if (th->ack) {
612
		rep.th.seq = th->ack_seq;
L
Linus Torvalds 已提交
613
	} else {
614 615 616
		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
617 618
	}

619
	memset(&arg, 0, sizeof(arg));
620 621 622 623
	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);

#ifdef CONFIG_TCP_MD5SIG
624 625 626 627 628 629 630 631 632 633
	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.
		 */
		sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev),
634 635
					     &tcp_hashinfo, ip_hdr(skb)->saddr,
					     th->source, ip_hdr(skb)->daddr,
636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654
					     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;
	}

655 656 657 658 659 660 661 662 663
	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;

664
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1],
665 666
				     key, ip_hdr(skb)->saddr,
				     ip_hdr(skb)->daddr, &rep.th);
667 668
	}
#endif
669 670
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
671
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
L
Linus Torvalds 已提交
672
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
673
	arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0;
674
	/* When socket is gone, all binding information is lost.
A
Alexey Kuznetsov 已提交
675 676
	 * routing might fail in this case. No choice here, if we choose to force
	 * input interface, we will misroute in case of asymmetric route.
677
	 */
A
Alexey Kuznetsov 已提交
678 679
	if (sk)
		arg.bound_dev_if = sk->sk_bound_dev_if;
L
Linus Torvalds 已提交
680

E
Eric Dumazet 已提交
681
	net = dev_net(skb_dst(skb)->dev);
682
	arg.tos = ip_hdr(skb)->tos;
683 684 685
	ip_send_unicast_reply(net, skb, &TCP_SKB_CB(skb)->header.h4.opt,
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
686

687 688
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
	TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
689 690 691 692 693 694 695 696

#ifdef CONFIG_TCP_MD5SIG
release_sk1:
	if (sk1) {
		rcu_read_unlock();
		sock_put(sk1);
	}
#endif
L
Linus Torvalds 已提交
697 698 699 700 701 702
}

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

703
static void tcp_v4_send_ack(struct sk_buff *skb, u32 seq, u32 ack,
704
			    u32 win, u32 tsval, u32 tsecr, int oif,
705
			    struct tcp_md5sig_key *key,
706
			    int reply_flags, u8 tos)
L
Linus Torvalds 已提交
707
{
708
	const struct tcphdr *th = tcp_hdr(skb);
L
Linus Torvalds 已提交
709 710
	struct {
		struct tcphdr th;
711
		__be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2)
712
#ifdef CONFIG_TCP_MD5SIG
713
			   + (TCPOLEN_MD5SIG_ALIGNED >> 2)
714 715
#endif
			];
L
Linus Torvalds 已提交
716 717
	} rep;
	struct ip_reply_arg arg;
E
Eric Dumazet 已提交
718
	struct net *net = dev_net(skb_dst(skb)->dev);
L
Linus Torvalds 已提交
719 720

	memset(&rep.th, 0, sizeof(struct tcphdr));
721
	memset(&arg, 0, sizeof(arg));
L
Linus Torvalds 已提交
722 723 724

	arg.iov[0].iov_base = (unsigned char *)&rep;
	arg.iov[0].iov_len  = sizeof(rep.th);
725
	if (tsecr) {
726 727 728
		rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
				   (TCPOPT_TIMESTAMP << 8) |
				   TCPOLEN_TIMESTAMP);
729 730
		rep.opt[1] = htonl(tsval);
		rep.opt[2] = htonl(tsecr);
731
		arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED;
L
Linus Torvalds 已提交
732 733 734 735 736 737 738 739 740 741 742
	}

	/* 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);

743 744
#ifdef CONFIG_TCP_MD5SIG
	if (key) {
745
		int offset = (tsecr) ? 3 : 0;
746 747 748 749 750 751 752 753

		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;

754
		tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset],
755 756
				    key, ip_hdr(skb)->saddr,
				    ip_hdr(skb)->daddr, &rep.th);
757 758
	}
#endif
759
	arg.flags = reply_flags;
760 761
	arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr,
				      ip_hdr(skb)->saddr, /* XXX */
L
Linus Torvalds 已提交
762 763
				      arg.iov[0].iov_len, IPPROTO_TCP, 0);
	arg.csumoffset = offsetof(struct tcphdr, check) / 2;
764 765
	if (oif)
		arg.bound_dev_if = oif;
766
	arg.tos = tos;
767 768 769
	ip_send_unicast_reply(net, skb, &TCP_SKB_CB(skb)->header.h4.opt,
			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
			      &arg, arg.iov[0].iov_len);
L
Linus Torvalds 已提交
770

771
	TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
L
Linus Torvalds 已提交
772 773 774 775
}

static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
{
776
	struct inet_timewait_sock *tw = inet_twsk(sk);
777
	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
L
Linus Torvalds 已提交
778

779
	tcp_v4_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
780
			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
781
			tcp_time_stamp + tcptw->tw_ts_offset,
782 783
			tcptw->tw_ts_recent,
			tw->tw_bound_dev_if,
784
			tcp_twsk_md5_key(tcptw),
785 786
			tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0,
			tw->tw_tos
787
			);
L
Linus Torvalds 已提交
788

789
	inet_twsk_put(tw);
L
Linus Torvalds 已提交
790 791
}

792
static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
793
				  struct request_sock *req)
L
Linus Torvalds 已提交
794
{
795 796 797 798 799 800
	/* 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,
801
			tcp_time_stamp,
802 803
			req->ts_recent,
			0,
E
Eric Dumazet 已提交
804 805
			tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
					  AF_INET),
806 807
			inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0,
			ip_hdr(skb)->tos);
L
Linus Torvalds 已提交
808 809 810
}

/*
811
 *	Send a SYN-ACK after having received a SYN.
812
 *	This still operates on a request_sock only, not on a big
L
Linus Torvalds 已提交
813 814
 *	socket.
 */
815
static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
816
			      struct flowi *fl,
817
			      struct request_sock *req,
818 819
			      u16 queue_mapping,
			      struct tcp_fastopen_cookie *foc)
L
Linus Torvalds 已提交
820
{
821
	const struct inet_request_sock *ireq = inet_rsk(req);
822
	struct flowi4 fl4;
L
Linus Torvalds 已提交
823
	int err = -1;
824
	struct sk_buff *skb;
L
Linus Torvalds 已提交
825 826

	/* First, grab a route. */
827
	if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
828
		return -1;
L
Linus Torvalds 已提交
829

830
	skb = tcp_make_synack(sk, dst, req, foc);
L
Linus Torvalds 已提交
831 832

	if (skb) {
833
		__tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr);
L
Linus Torvalds 已提交
834

835
		skb_set_queue_mapping(skb, queue_mapping);
836 837
		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
					    ireq->ir_rmt_addr,
838
					    ireq->opt);
839
		err = net_xmit_eval(err);
L
Linus Torvalds 已提交
840 841 842 843 844 845
	}

	return err;
}

/*
846
 *	IPv4 request_sock destructor.
L
Linus Torvalds 已提交
847
 */
848
static void tcp_v4_reqsk_destructor(struct request_sock *req)
L
Linus Torvalds 已提交
849
{
J
Jesper Juhl 已提交
850
	kfree(inet_rsk(req)->opt);
L
Linus Torvalds 已提交
851 852
}

853
/*
E
Eric Dumazet 已提交
854
 * Return true if a syncookie should be sent
855
 */
E
Eric Dumazet 已提交
856
bool tcp_syn_flood_action(struct sock *sk,
857 858
			 const struct sk_buff *skb,
			 const char *proto)
L
Linus Torvalds 已提交
859
{
860
	const char *msg = "Dropping request";
E
Eric Dumazet 已提交
861
	bool want_cookie = false;
862 863
	struct listen_sock *lopt;

864
#ifdef CONFIG_SYN_COOKIES
865
	if (sysctl_tcp_syncookies) {
866
		msg = "Sending cookies";
E
Eric Dumazet 已提交
867
		want_cookie = true;
868 869
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDOCOOKIES);
	} else
870
#endif
871 872 873
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPREQQFULLDROP);

	lopt = inet_csk(sk)->icsk_accept_queue.listen_opt;
874
	if (!lopt->synflood_warned && sysctl_tcp_syncookies != 2) {
875
		lopt->synflood_warned = 1;
876
		pr_info("%s: Possible SYN flooding on port %d. %s.  Check SNMP counters.\n",
877 878 879
			proto, ntohs(tcp_hdr(skb)->dest), msg);
	}
	return want_cookie;
880
}
881
EXPORT_SYMBOL(tcp_syn_flood_action);
L
Linus Torvalds 已提交
882

883 884 885 886 887 888 889 890
#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
891 892 893
struct tcp_md5sig_key *tcp_md5_do_lookup(struct sock *sk,
					 const union tcp_md5_addr *addr,
					 int family)
894 895
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
896 897
	struct tcp_md5sig_key *key;
	unsigned int size = sizeof(struct in_addr);
898
	struct tcp_md5sig_info *md5sig;
899

900 901
	/* caller either holds rcu_read_lock() or socket lock */
	md5sig = rcu_dereference_check(tp->md5sig_info,
902 903
				       sock_owned_by_user(sk) ||
				       lockdep_is_held(&sk->sk_lock.slock));
904
	if (!md5sig)
905
		return NULL;
E
Eric Dumazet 已提交
906 907 908 909
#if IS_ENABLED(CONFIG_IPV6)
	if (family == AF_INET6)
		size = sizeof(struct in6_addr);
#endif
910
	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
E
Eric Dumazet 已提交
911 912 913 914
		if (key->family != family)
			continue;
		if (!memcmp(&key->addr, addr, size))
			return key;
915 916 917
	}
	return NULL;
}
E
Eric Dumazet 已提交
918
EXPORT_SYMBOL(tcp_md5_do_lookup);
919 920 921 922

struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk,
					 struct sock *addr_sk)
{
E
Eric Dumazet 已提交
923 924 925 926
	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);
927 928 929
}
EXPORT_SYMBOL(tcp_v4_md5_lookup);

A
Adrian Bunk 已提交
930 931
static struct tcp_md5sig_key *tcp_v4_reqsk_md5_lookup(struct sock *sk,
						      struct request_sock *req)
932
{
E
Eric Dumazet 已提交
933 934
	union tcp_md5_addr *addr;

935
	addr = (union tcp_md5_addr *)&inet_rsk(req)->ir_rmt_addr;
E
Eric Dumazet 已提交
936
	return tcp_md5_do_lookup(sk, addr, AF_INET);
937 938 939
}

/* This can be called on a newly created socket, from other files */
E
Eric Dumazet 已提交
940 941
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
		   int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
942 943
{
	/* Add Key to the list */
944
	struct tcp_md5sig_key *key;
945
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
946
	struct tcp_md5sig_info *md5sig;
947

948
	key = tcp_md5_do_lookup(sk, addr, family);
949 950
	if (key) {
		/* Pre-existing entry - just update that one. */
E
Eric Dumazet 已提交
951
		memcpy(key->key, newkey, newkeylen);
952
		key->keylen = newkeylen;
E
Eric Dumazet 已提交
953 954
		return 0;
	}
955

956 957
	md5sig = rcu_dereference_protected(tp->md5sig_info,
					   sock_owned_by_user(sk));
E
Eric Dumazet 已提交
958 959 960
	if (!md5sig) {
		md5sig = kmalloc(sizeof(*md5sig), gfp);
		if (!md5sig)
961 962
			return -ENOMEM;

E
Eric Dumazet 已提交
963 964
		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
		INIT_HLIST_HEAD(&md5sig->head);
965
		rcu_assign_pointer(tp->md5sig_info, md5sig);
E
Eric Dumazet 已提交
966
	}
967

968
	key = sock_kmalloc(sk, sizeof(*key), gfp);
E
Eric Dumazet 已提交
969 970
	if (!key)
		return -ENOMEM;
971
	if (!tcp_alloc_md5sig_pool()) {
972
		sock_kfree_s(sk, key, sizeof(*key));
E
Eric Dumazet 已提交
973
		return -ENOMEM;
974
	}
E
Eric Dumazet 已提交
975 976 977 978 979 980 981 982

	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);
983 984
	return 0;
}
E
Eric Dumazet 已提交
985
EXPORT_SYMBOL(tcp_md5_do_add);
986

E
Eric Dumazet 已提交
987
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
988
{
E
Eric Dumazet 已提交
989 990
	struct tcp_md5sig_key *key;

991
	key = tcp_md5_do_lookup(sk, addr, family);
E
Eric Dumazet 已提交
992 993 994
	if (!key)
		return -ENOENT;
	hlist_del_rcu(&key->node);
995
	atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
996 997
	kfree_rcu(key, rcu);
	return 0;
998
}
E
Eric Dumazet 已提交
999
EXPORT_SYMBOL(tcp_md5_do_del);
1000

1001
static void tcp_clear_md5_list(struct sock *sk)
1002 1003
{
	struct tcp_sock *tp = tcp_sk(sk);
E
Eric Dumazet 已提交
1004
	struct tcp_md5sig_key *key;
1005
	struct hlist_node *n;
1006
	struct tcp_md5sig_info *md5sig;
1007

1008 1009
	md5sig = rcu_dereference_protected(tp->md5sig_info, 1);

1010
	hlist_for_each_entry_safe(key, n, &md5sig->head, node) {
E
Eric Dumazet 已提交
1011
		hlist_del_rcu(&key->node);
1012
		atomic_sub(sizeof(*key), &sk->sk_omem_alloc);
E
Eric Dumazet 已提交
1013
		kfree_rcu(key, rcu);
1014 1015 1016
	}
}

1017 1018
static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
				 int optlen)
1019 1020 1021 1022 1023 1024 1025
{
	struct tcp_md5sig cmd;
	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr;

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

1026
	if (copy_from_user(&cmd, optval, sizeof(cmd)))
1027 1028 1029 1030 1031
		return -EFAULT;

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

1032
	if (!cmd.tcpm_keylen)
E
Eric Dumazet 已提交
1033 1034
		return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
				      AF_INET);
1035 1036 1037 1038

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

E
Eric Dumazet 已提交
1039 1040 1041
	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);
1042 1043
}

1044 1045
static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp,
					__be32 daddr, __be32 saddr, int nbytes)
1046 1047
{
	struct tcp4_pseudohdr *bp;
1048
	struct scatterlist sg;
1049 1050 1051 1052

	bp = &hp->md5_blk.ip4;

	/*
1053
	 * 1. the TCP pseudo-header (in the order: source IP address,
1054 1055 1056 1057 1058 1059
	 * destination IP address, zero-padded protocol number, and
	 * segment length)
	 */
	bp->saddr = saddr;
	bp->daddr = daddr;
	bp->pad = 0;
1060
	bp->protocol = IPPROTO_TCP;
1061
	bp->len = cpu_to_be16(nbytes);
1062

1063 1064 1065 1066
	sg_init_one(&sg, bp, sizeof(*bp));
	return crypto_hash_update(&hp->md5_desc, &sg, sizeof(*bp));
}

E
Eric Dumazet 已提交
1067
static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1068
			       __be32 daddr, __be32 saddr, const struct tcphdr *th)
1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086
{
	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))
1087 1088 1089 1090
		goto clear_hash;

	tcp_put_md5sig_pool();
	return 0;
1091

1092 1093 1094 1095
clear_hash:
	tcp_put_md5sig_pool();
clear_hash_noput:
	memset(md5_hash, 0, 16);
1096
	return 1;
1097 1098
}

1099
int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key,
E
Eric Dumazet 已提交
1100 1101
			const struct sock *sk, const struct request_sock *req,
			const struct sk_buff *skb)
1102
{
1103 1104
	struct tcp_md5sig_pool *hp;
	struct hash_desc *desc;
E
Eric Dumazet 已提交
1105
	const struct tcphdr *th = tcp_hdr(skb);
1106 1107 1108
	__be32 saddr, daddr;

	if (sk) {
E
Eric Dumazet 已提交
1109 1110
		saddr = inet_sk(sk)->inet_saddr;
		daddr = inet_sk(sk)->inet_daddr;
1111
	} else if (req) {
1112 1113
		saddr = inet_rsk(req)->ir_loc_addr;
		daddr = inet_rsk(req)->ir_rmt_addr;
1114
	} else {
1115 1116 1117
		const struct iphdr *iph = ip_hdr(skb);
		saddr = iph->saddr;
		daddr = iph->daddr;
1118
	}
1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146

	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;
1147
}
1148
EXPORT_SYMBOL(tcp_v4_md5_hash_skb);
1149

1150 1151
static bool __tcp_v4_inbound_md5_hash(struct sock *sk,
				      const struct sk_buff *skb)
1152 1153 1154 1155 1156 1157 1158 1159 1160
{
	/*
	 * 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.
	 */
1161
	const __u8 *hash_location = NULL;
1162
	struct tcp_md5sig_key *hash_expected;
1163
	const struct iphdr *iph = ip_hdr(skb);
1164
	const struct tcphdr *th = tcp_hdr(skb);
1165 1166 1167
	int genhash;
	unsigned char newhash[16];

E
Eric Dumazet 已提交
1168 1169
	hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr,
					  AF_INET);
1170
	hash_location = tcp_parse_md5sig_option(th);
1171 1172 1173

	/* We've parsed the options - do we have a hash? */
	if (!hash_expected && !hash_location)
E
Eric Dumazet 已提交
1174
		return false;
1175 1176

	if (hash_expected && !hash_location) {
1177
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND);
E
Eric Dumazet 已提交
1178
		return true;
1179 1180 1181
	}

	if (!hash_expected && hash_location) {
1182
		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED);
E
Eric Dumazet 已提交
1183
		return true;
1184 1185 1186 1187 1188
	}

	/* Okay, so this is hash_expected and hash_location -
	 * so we need to calculate the checksum.
	 */
1189 1190 1191
	genhash = tcp_v4_md5_hash_skb(newhash,
				      hash_expected,
				      NULL, NULL, skb);
1192 1193

	if (genhash || memcmp(hash_location, newhash, 16) != 0) {
1194 1195 1196 1197 1198
		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
1199
		return true;
1200
	}
E
Eric Dumazet 已提交
1201
	return false;
1202 1203
}

1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214
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;
}

1215 1216
#endif

1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
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);
}

1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243
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;
}

1244
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
L
Linus Torvalds 已提交
1245
	.family		=	PF_INET,
1246
	.obj_size	=	sizeof(struct tcp_request_sock),
1247
	.rtx_syn_ack	=	tcp_rtx_synack,
1248 1249
	.send_ack	=	tcp_v4_reqsk_send_ack,
	.destructor	=	tcp_v4_reqsk_destructor,
L
Linus Torvalds 已提交
1250
	.send_reset	=	tcp_v4_send_reset,
S
stephen hemminger 已提交
1251
	.syn_ack_timeout =	tcp_syn_ack_timeout,
L
Linus Torvalds 已提交
1252 1253
};

1254
static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
1255
	.mss_clamp	=	TCP_MSS_DEFAULT,
1256
#ifdef CONFIG_TCP_MD5SIG
1257
	.md5_lookup	=	tcp_v4_reqsk_md5_lookup,
1258
	.calc_md5_hash	=	tcp_v4_md5_hash_skb,
1259
#endif
1260
	.init_req	=	tcp_v4_init_req,
1261 1262 1263
#ifdef CONFIG_SYN_COOKIES
	.cookie_init_seq =	cookie_v4_init_sequence,
#endif
1264
	.route_req	=	tcp_v4_route_req,
1265
	.init_seq	=	tcp_v4_init_sequence,
1266
	.send_synack	=	tcp_v4_send_synack,
1267
	.queue_hash_add =	inet_csk_reqsk_queue_hash_add,
1268
};
1269

L
Linus Torvalds 已提交
1270 1271 1272
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
1273
	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
L
Linus Torvalds 已提交
1274 1275
		goto drop;

O
Octavian Purdila 已提交
1276 1277
	return tcp_conn_request(&tcp_request_sock_ops,
				&tcp_request_sock_ipv4_ops, sk, skb);
L
Linus Torvalds 已提交
1278 1279

drop:
1280
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1281 1282
	return 0;
}
E
Eric Dumazet 已提交
1283
EXPORT_SYMBOL(tcp_v4_conn_request);
L
Linus Torvalds 已提交
1284 1285 1286 1287 1288 1289 1290


/*
 * 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,
1291
				  struct request_sock *req,
L
Linus Torvalds 已提交
1292 1293
				  struct dst_entry *dst)
{
1294
	struct inet_request_sock *ireq;
L
Linus Torvalds 已提交
1295 1296 1297
	struct inet_sock *newinet;
	struct tcp_sock *newtp;
	struct sock *newsk;
1298 1299 1300
#ifdef CONFIG_TCP_MD5SIG
	struct tcp_md5sig_key *key;
#endif
1301
	struct ip_options_rcu *inet_opt;
L
Linus Torvalds 已提交
1302 1303 1304 1305 1306 1307

	if (sk_acceptq_is_full(sk))
		goto exit_overflow;

	newsk = tcp_create_openreq_child(sk, req, skb);
	if (!newsk)
1308
		goto exit_nonewsk;
L
Linus Torvalds 已提交
1309

1310
	newsk->sk_gso_type = SKB_GSO_TCPV4;
1311
	inet_sk_rx_dst_set(newsk, skb);
L
Linus Torvalds 已提交
1312 1313 1314

	newtp		      = tcp_sk(newsk);
	newinet		      = inet_sk(newsk);
1315
	ireq		      = inet_rsk(req);
1316 1317 1318
	newinet->inet_daddr   = ireq->ir_rmt_addr;
	newinet->inet_rcv_saddr = ireq->ir_loc_addr;
	newinet->inet_saddr	      = ireq->ir_loc_addr;
1319 1320
	inet_opt	      = ireq->opt;
	rcu_assign_pointer(newinet->inet_opt, inet_opt);
1321
	ireq->opt	      = NULL;
1322
	newinet->mc_index     = inet_iif(skb);
1323
	newinet->mc_ttl	      = ip_hdr(skb)->ttl;
1324
	newinet->rcv_tos      = ip_hdr(skb)->tos;
1325
	inet_csk(newsk)->icsk_ext_hdr_len = 0;
1326
	inet_set_txhash(newsk);
1327 1328
	if (inet_opt)
		inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
E
Eric Dumazet 已提交
1329
	newinet->inet_id = newtp->write_seq ^ jiffies;
L
Linus Torvalds 已提交
1330

E
Eric Dumazet 已提交
1331 1332 1333 1334 1335 1336 1337
	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() */
	}
1338 1339
	sk_setup_caps(newsk, dst);

L
Linus Torvalds 已提交
1340
	tcp_sync_mss(newsk, dst_mtu(dst));
1341
	newtp->advmss = dst_metric_advmss(dst);
1342 1343 1344 1345
	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
1346 1347
	tcp_initialize_rcv_mss(newsk);

1348 1349
#ifdef CONFIG_TCP_MD5SIG
	/* Copy over the MD5 key from the original socket */
E
Eric Dumazet 已提交
1350 1351
	key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr,
				AF_INET);
E
Eric Dumazet 已提交
1352
	if (key != NULL) {
1353 1354 1355 1356 1357 1358
		/*
		 * 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
1359 1360
		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
1361
		sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
1362 1363 1364
	}
#endif

1365 1366
	if (__inet_inherit_port(sk, newsk) < 0)
		goto put_and_exit;
1367
	__inet_hash_nolisten(newsk, NULL);
L
Linus Torvalds 已提交
1368 1369 1370 1371

	return newsk;

exit_overflow:
1372
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS);
1373 1374
exit_nonewsk:
	dst_release(dst);
L
Linus Torvalds 已提交
1375
exit:
1376
	NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
L
Linus Torvalds 已提交
1377
	return NULL;
1378
put_and_exit:
1379 1380
	inet_csk_prepare_forced_close(newsk);
	tcp_done(newsk);
1381
	goto exit;
L
Linus Torvalds 已提交
1382
}
E
Eric Dumazet 已提交
1383
EXPORT_SYMBOL(tcp_v4_syn_recv_sock);
L
Linus Torvalds 已提交
1384 1385 1386

static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
{
1387
	struct tcphdr *th = tcp_hdr(skb);
1388
	const struct iphdr *iph = ip_hdr(skb);
L
Linus Torvalds 已提交
1389
	struct sock *nsk;
1390
	struct request_sock **prev;
L
Linus Torvalds 已提交
1391
	/* Find possible connection requests. */
1392 1393
	struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
						       iph->saddr, iph->daddr);
L
Linus Torvalds 已提交
1394
	if (req)
1395
		return tcp_check_req(sk, skb, req, prev, false);
L
Linus Torvalds 已提交
1396

1397
	nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
1398
			th->source, iph->daddr, th->dest, inet_iif(skb));
L
Linus Torvalds 已提交
1399 1400 1401 1402 1403 1404

	if (nsk) {
		if (nsk->sk_state != TCP_TIME_WAIT) {
			bh_lock_sock(nsk);
			return nsk;
		}
1405
		inet_twsk_put(inet_twsk(nsk));
L
Linus Torvalds 已提交
1406 1407 1408 1409
		return NULL;
	}

#ifdef CONFIG_SYN_COOKIES
1410
	if (!th->syn)
C
Cong Wang 已提交
1411
		sk = cookie_v4_check(sk, skb);
L
Linus Torvalds 已提交
1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425
#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)
{
1426 1427
	struct sock *rsk;

L
Linus Torvalds 已提交
1428
	if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */
1429 1430
		struct dst_entry *dst = sk->sk_rx_dst;

1431
		sock_rps_save_rxhash(sk, skb);
1432
		if (dst) {
E
Eric Dumazet 已提交
1433 1434
			if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif ||
			    dst->ops->check(dst, 0) == NULL) {
1435 1436 1437 1438
				dst_release(dst);
				sk->sk_rx_dst = NULL;
			}
		}
1439
		tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len);
L
Linus Torvalds 已提交
1440 1441 1442
		return 0;
	}

1443
	if (skb->len < tcp_hdrlen(skb) || tcp_checksum_complete(skb))
L
Linus Torvalds 已提交
1444 1445 1446 1447 1448 1449 1450 1451
		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) {
1452
			sock_rps_save_rxhash(nsk, skb);
1453 1454
			if (tcp_child_process(sk, nsk, skb)) {
				rsk = nsk;
L
Linus Torvalds 已提交
1455
				goto reset;
1456
			}
L
Linus Torvalds 已提交
1457 1458
			return 0;
		}
1459
	} else
1460
		sock_rps_save_rxhash(sk, skb);
1461

1462
	if (tcp_rcv_state_process(sk, skb, tcp_hdr(skb), skb->len)) {
1463
		rsk = sk;
L
Linus Torvalds 已提交
1464
		goto reset;
1465
	}
L
Linus Torvalds 已提交
1466 1467 1468
	return 0;

reset:
1469
	tcp_v4_send_reset(rsk, skb);
L
Linus Torvalds 已提交
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479
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:
1480
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_CSUMERRORS);
1481
	TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1482 1483
	goto discard;
}
E
Eric Dumazet 已提交
1484
EXPORT_SYMBOL(tcp_v4_do_rcv);
L
Linus Torvalds 已提交
1485

1486
void tcp_v4_early_demux(struct sk_buff *skb)
D
David S. Miller 已提交
1487 1488 1489 1490 1491 1492
{
	const struct iphdr *iph;
	const struct tcphdr *th;
	struct sock *sk;

	if (skb->pkt_type != PACKET_HOST)
1493
		return;
D
David S. Miller 已提交
1494

1495
	if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr)))
1496
		return;
D
David S. Miller 已提交
1497 1498

	iph = ip_hdr(skb);
1499
	th = tcp_hdr(skb);
D
David S. Miller 已提交
1500 1501

	if (th->doff < sizeof(struct tcphdr) / 4)
1502
		return;
D
David S. Miller 已提交
1503

1504
	sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
D
David S. Miller 已提交
1505
				       iph->saddr, th->source,
1506
				       iph->daddr, ntohs(th->dest),
E
Eric Dumazet 已提交
1507
				       skb->skb_iif);
D
David S. Miller 已提交
1508 1509 1510 1511 1512
	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
1513

D
David S. Miller 已提交
1514 1515
			if (dst)
				dst = dst_check(dst, 0);
1516
			if (dst &&
E
Eric Dumazet 已提交
1517
			    inet_sk(sk)->rx_dst_ifindex == skb->skb_iif)
1518
				skb_dst_set_noref(skb, dst);
D
David S. Miller 已提交
1519 1520 1521 1522
		}
	}
}

E
Eric Dumazet 已提交
1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540
/* 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;

1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551
	/* 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
1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
	__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
1578 1579 1580 1581 1582 1583
/*
 *	From tcp_input.c
 */

int tcp_v4_rcv(struct sk_buff *skb)
{
1584
	const struct iphdr *iph;
1585
	const struct tcphdr *th;
L
Linus Torvalds 已提交
1586 1587
	struct sock *sk;
	int ret;
1588
	struct net *net = dev_net(skb->dev);
L
Linus Torvalds 已提交
1589 1590 1591 1592 1593

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

	/* Count it even if it's bad */
1594
	TCP_INC_STATS_BH(net, TCP_MIB_INSEGS);
L
Linus Torvalds 已提交
1595 1596 1597 1598

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

1599
	th = tcp_hdr(skb);
L
Linus Torvalds 已提交
1600 1601 1602 1603 1604 1605 1606 1607

	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
1608
	 * provided case of th->doff==0 is eliminated.
L
Linus Torvalds 已提交
1609
	 * So, we defer the checks. */
1610 1611

	if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo))
1612
		goto csum_error;
L
Linus Torvalds 已提交
1613

1614
	th = tcp_hdr(skb);
1615
	iph = ip_hdr(skb);
1616 1617 1618 1619 1620 1621 1622
	/* 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
1623 1624 1625 1626
	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);
1627
	TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
1628
	TCP_SKB_CB(skb)->tcp_tw_isn = 0;
1629
	TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
L
Linus Torvalds 已提交
1630 1631
	TCP_SKB_CB(skb)->sacked	 = 0;

1632
	sk = __inet_lookup_skb(&tcp_hashinfo, skb, th->source, th->dest);
L
Linus Torvalds 已提交
1633 1634 1635
	if (!sk)
		goto no_tcp_socket;

E
Eric Dumazet 已提交
1636 1637 1638 1639
process:
	if (sk->sk_state == TCP_TIME_WAIT)
		goto do_time_wait;

1640 1641
	if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
		NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
1642
		goto discard_and_relse;
1643
	}
1644

L
Linus Torvalds 已提交
1645 1646
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;
1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658

#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

1659
	nf_reset(skb);
L
Linus Torvalds 已提交
1660

1661
	if (sk_filter(sk, skb))
L
Linus Torvalds 已提交
1662 1663
		goto discard_and_relse;

1664
	sk_mark_napi_id(sk, skb);
L
Linus Torvalds 已提交
1665 1666
	skb->dev = NULL;

1667
	bh_lock_sock_nested(sk);
L
Linus Torvalds 已提交
1668 1669
	ret = 0;
	if (!sock_owned_by_user(sk)) {
D
Dan Williams 已提交
1670
		if (!tcp_prequeue(sk, skb))
L
Linus Torvalds 已提交
1671
			ret = tcp_v4_do_rcv(sk, skb);
1672 1673
	} else if (unlikely(sk_add_backlog(sk, skb,
					   sk->sk_rcvbuf + sk->sk_sndbuf))) {
Z
Zhu Yi 已提交
1674
		bh_unlock_sock(sk);
1675
		NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
Z
Zhu Yi 已提交
1676 1677
		goto discard_and_relse;
	}
L
Linus Torvalds 已提交
1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688
	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)) {
1689 1690
csum_error:
		TCP_INC_STATS_BH(net, TCP_MIB_CSUMERRORS);
L
Linus Torvalds 已提交
1691
bad_packet:
1692
		TCP_INC_STATS_BH(net, TCP_MIB_INERRS);
L
Linus Torvalds 已提交
1693
	} else {
1694
		tcp_v4_send_reset(NULL, skb);
L
Linus Torvalds 已提交
1695 1696 1697 1698 1699
	}

discard_it:
	/* Discard frame. */
	kfree_skb(skb);
1700
	return 0;
L
Linus Torvalds 已提交
1701 1702 1703 1704 1705 1706 1707

discard_and_relse:
	sock_put(sk);
	goto discard_it;

do_time_wait:
	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
1708
		inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1709 1710 1711
		goto discard_it;
	}

1712
	if (skb->len < (th->doff << 2)) {
1713
		inet_twsk_put(inet_twsk(sk));
1714 1715 1716 1717 1718
		goto bad_packet;
	}
	if (tcp_checksum_complete(skb)) {
		inet_twsk_put(inet_twsk(sk));
		goto csum_error;
L
Linus Torvalds 已提交
1719
	}
1720
	switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) {
L
Linus Torvalds 已提交
1721
	case TCP_TW_SYN: {
1722
		struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev),
1723
							&tcp_hashinfo,
1724
							iph->saddr, th->source,
1725
							iph->daddr, th->dest,
1726
							inet_iif(skb));
L
Linus Torvalds 已提交
1727
		if (sk2) {
1728 1729
			inet_twsk_deschedule(inet_twsk(sk), &tcp_death_row);
			inet_twsk_put(inet_twsk(sk));
L
Linus Torvalds 已提交
1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744
			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;
}

1745 1746 1747 1748 1749
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
1750

1751
void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb)
E
Eric Dumazet 已提交
1752 1753 1754
{
	struct dst_entry *dst = skb_dst(skb);

1755 1756 1757 1758 1759
	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
1760
}
1761
EXPORT_SYMBOL(inet_sk_rx_dst_set);
E
Eric Dumazet 已提交
1762

1763
const struct inet_connection_sock_af_ops ipv4_specific = {
1764 1765 1766
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = tcp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
E
Eric Dumazet 已提交
1767
	.sk_rx_dst_set	   = inet_sk_rx_dst_set,
1768 1769 1770 1771 1772 1773 1774
	.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),
1775
	.bind_conflict	   = inet_csk_bind_conflict,
1776
#ifdef CONFIG_COMPAT
1777 1778
	.compat_setsockopt = compat_ip_setsockopt,
	.compat_getsockopt = compat_ip_getsockopt,
1779
#endif
1780
	.mtu_reduced	   = tcp_v4_mtu_reduced,
L
Linus Torvalds 已提交
1781
};
E
Eric Dumazet 已提交
1782
EXPORT_SYMBOL(ipv4_specific);
L
Linus Torvalds 已提交
1783

1784
#ifdef CONFIG_TCP_MD5SIG
1785
static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = {
1786
	.md5_lookup		= tcp_v4_md5_lookup,
1787
	.calc_md5_hash		= tcp_v4_md5_hash_skb,
1788 1789
	.md5_parse		= tcp_v4_parse_md5_keys,
};
1790
#endif
1791

L
Linus Torvalds 已提交
1792 1793 1794 1795 1796
/* 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)
{
1797
	struct inet_connection_sock *icsk = inet_csk(sk);
L
Linus Torvalds 已提交
1798

1799
	tcp_init_sock(sk);
L
Linus Torvalds 已提交
1800

1801
	icsk->icsk_af_ops = &ipv4_specific;
1802

1803
#ifdef CONFIG_TCP_MD5SIG
1804
	tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific;
1805
#endif
L
Linus Torvalds 已提交
1806 1807 1808 1809

	return 0;
}

1810
void tcp_v4_destroy_sock(struct sock *sk)
L
Linus Torvalds 已提交
1811 1812 1813 1814 1815
{
	struct tcp_sock *tp = tcp_sk(sk);

	tcp_clear_xmit_timers(sk);

1816
	tcp_cleanup_congestion_control(sk);
1817

L
Linus Torvalds 已提交
1818
	/* Cleanup up the write buffer. */
1819
	tcp_write_queue_purge(sk);
L
Linus Torvalds 已提交
1820 1821

	/* Cleans up our, hopefully empty, out_of_order_queue. */
1822
	__skb_queue_purge(&tp->out_of_order_queue);
L
Linus Torvalds 已提交
1823

1824 1825 1826
#ifdef CONFIG_TCP_MD5SIG
	/* Clean up the MD5 key list, if any */
	if (tp->md5sig_info) {
E
Eric Dumazet 已提交
1827
		tcp_clear_md5_list(sk);
1828
		kfree_rcu(tp->md5sig_info, rcu);
1829 1830 1831
		tp->md5sig_info = NULL;
	}
#endif
C
Chris Leech 已提交
1832

L
Linus Torvalds 已提交
1833 1834 1835 1836
	/* Clean prequeue, it must be empty really */
	__skb_queue_purge(&tp->ucopy.prequeue);

	/* Clean up a referenced TCP bind bucket. */
1837
	if (inet_csk(sk)->icsk_bind_hash)
1838
		inet_put_port(sk);
L
Linus Torvalds 已提交
1839

1840
	BUG_ON(tp->fastopen_rsk != NULL);
1841

1842 1843 1844
	/* If socket is aborted during connect operation */
	tcp_free_fastopen_req(tp);

1845
	sk_sockets_allocated_dec(sk);
G
Glauber Costa 已提交
1846
	sock_release_memcg(sk);
L
Linus Torvalds 已提交
1847 1848 1849 1850 1851 1852
}
EXPORT_SYMBOL(tcp_v4_destroy_sock);

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

1853 1854 1855 1856 1857
/*
 * 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
1858 1859
static void *listening_get_next(struct seq_file *seq, void *cur)
{
1860
	struct inet_connection_sock *icsk;
1861
	struct hlist_nulls_node *node;
L
Linus Torvalds 已提交
1862
	struct sock *sk = cur;
1863
	struct inet_listen_hashbucket *ilb;
J
Jianjun Kong 已提交
1864
	struct tcp_iter_state *st = seq->private;
1865
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1866 1867

	if (!sk) {
1868
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
1869
		spin_lock_bh(&ilb->lock);
1870
		sk = sk_nulls_head(&ilb->head);
1871
		st->offset = 0;
L
Linus Torvalds 已提交
1872 1873
		goto get_sk;
	}
1874
	ilb = &tcp_hashinfo.listening_hash[st->bucket];
L
Linus Torvalds 已提交
1875
	++st->num;
1876
	++st->offset;
L
Linus Torvalds 已提交
1877 1878

	if (st->state == TCP_SEQ_STATE_OPENREQ) {
1879
		struct request_sock *req = cur;
L
Linus Torvalds 已提交
1880

1881
		icsk = inet_csk(st->syn_wait_sk);
L
Linus Torvalds 已提交
1882 1883 1884
		req = req->dl_next;
		while (1) {
			while (req) {
1885
				if (req->rsk_ops->family == st->family) {
L
Linus Torvalds 已提交
1886 1887 1888 1889 1890
					cur = req;
					goto out;
				}
				req = req->dl_next;
			}
1891
			if (++st->sbucket >= icsk->icsk_accept_queue.listen_opt->nr_table_entries)
L
Linus Torvalds 已提交
1892 1893
				break;
get_req:
1894
			req = icsk->icsk_accept_queue.listen_opt->syn_table[st->sbucket];
L
Linus Torvalds 已提交
1895
		}
E
Eric Dumazet 已提交
1896
		sk	  = sk_nulls_next(st->syn_wait_sk);
L
Linus Torvalds 已提交
1897
		st->state = TCP_SEQ_STATE_LISTENING;
1898
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
1899
	} else {
1900
		icsk = inet_csk(sk);
1901 1902
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue))
L
Linus Torvalds 已提交
1903
			goto start_req;
1904
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
E
Eric Dumazet 已提交
1905
		sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
1906 1907
	}
get_sk:
1908
	sk_nulls_for_each_from(sk, node) {
1909 1910 1911
		if (!net_eq(sock_net(sk), net))
			continue;
		if (sk->sk_family == st->family) {
L
Linus Torvalds 已提交
1912 1913 1914
			cur = sk;
			goto out;
		}
1915
		icsk = inet_csk(sk);
1916 1917
		read_lock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
		if (reqsk_queue_len(&icsk->icsk_accept_queue)) {
L
Linus Torvalds 已提交
1918 1919 1920 1921 1922 1923 1924
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;
		}
1925
		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
L
Linus Torvalds 已提交
1926
	}
1927
	spin_unlock_bh(&ilb->lock);
1928
	st->offset = 0;
1929
	if (++st->bucket < INET_LHTABLE_SIZE) {
1930 1931
		ilb = &tcp_hashinfo.listening_hash[st->bucket];
		spin_lock_bh(&ilb->lock);
1932
		sk = sk_nulls_head(&ilb->head);
L
Linus Torvalds 已提交
1933 1934 1935 1936 1937 1938 1939 1940 1941
		goto get_sk;
	}
	cur = NULL;
out:
	return cur;
}

static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
{
1942 1943 1944 1945 1946 1947
	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
1948 1949 1950 1951 1952 1953 1954 1955

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

E
Eric Dumazet 已提交
1956
static inline bool empty_bucket(const struct tcp_iter_state *st)
1957
{
E
Eric Dumazet 已提交
1958
	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain);
1959 1960
}

1961 1962 1963 1964
/*
 * 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
1965 1966
static void *established_get_first(struct seq_file *seq)
{
J
Jianjun Kong 已提交
1967
	struct tcp_iter_state *st = seq->private;
1968
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1969 1970
	void *rc = NULL;

1971 1972
	st->offset = 0;
	for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) {
L
Linus Torvalds 已提交
1973
		struct sock *sk;
1974
		struct hlist_nulls_node *node;
1975
		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
L
Linus Torvalds 已提交
1976

1977 1978 1979 1980
		/* Lockless fast path for the common case of empty buckets */
		if (empty_bucket(st))
			continue;

1981
		spin_lock_bh(lock);
1982
		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
1983
			if (sk->sk_family != st->family ||
1984
			    !net_eq(sock_net(sk), net)) {
L
Linus Torvalds 已提交
1985 1986 1987 1988 1989
				continue;
			}
			rc = sk;
			goto out;
		}
1990
		spin_unlock_bh(lock);
L
Linus Torvalds 已提交
1991 1992 1993 1994 1995 1996 1997 1998
	}
out:
	return rc;
}

static void *established_get_next(struct seq_file *seq, void *cur)
{
	struct sock *sk = cur;
1999
	struct hlist_nulls_node *node;
J
Jianjun Kong 已提交
2000
	struct tcp_iter_state *st = seq->private;
2001
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2002 2003

	++st->num;
2004
	++st->offset;
L
Linus Torvalds 已提交
2005

E
Eric Dumazet 已提交
2006
	sk = sk_nulls_next(sk);
L
Linus Torvalds 已提交
2007

2008
	sk_nulls_for_each_from(sk, node) {
2009
		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
E
Eric Dumazet 已提交
2010
			return sk;
L
Linus Torvalds 已提交
2011 2012
	}

E
Eric Dumazet 已提交
2013 2014 2015
	spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
	++st->bucket;
	return established_get_first(seq);
L
Linus Torvalds 已提交
2016 2017 2018 2019
}

static void *established_get_idx(struct seq_file *seq, loff_t pos)
{
2020 2021 2022 2023 2024
	struct tcp_iter_state *st = seq->private;
	void *rc;

	st->bucket = 0;
	rc = established_get_first(seq);
L
Linus Torvalds 已提交
2025 2026 2027 2028

	while (rc && pos) {
		rc = established_get_next(seq, rc);
		--pos;
2029
	}
L
Linus Torvalds 已提交
2030 2031 2032 2033 2034 2035
	return rc;
}

static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
{
	void *rc;
J
Jianjun Kong 已提交
2036
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048

	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;
}

2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067
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
2068
		st->state = TCP_SEQ_STATE_ESTABLISHED;
2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082
		/* 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
2083 2084
static void *tcp_seq_start(struct seq_file *seq, loff_t *pos)
{
J
Jianjun Kong 已提交
2085
	struct tcp_iter_state *st = seq->private;
2086 2087 2088 2089 2090 2091 2092 2093
	void *rc;

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

L
Linus Torvalds 已提交
2094 2095
	st->state = TCP_SEQ_STATE_LISTENING;
	st->num = 0;
2096 2097 2098 2099 2100 2101 2102
	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
2103 2104 2105 2106
}

static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
2107
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120
	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;
2121 2122
			st->bucket = 0;
			st->offset = 0;
L
Linus Torvalds 已提交
2123 2124 2125 2126 2127 2128 2129 2130 2131
			rc	  = established_get_first(seq);
		}
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		rc = established_get_next(seq, v);
		break;
	}
out:
	++*pos;
2132
	st->last_pos = *pos;
L
Linus Torvalds 已提交
2133 2134 2135 2136 2137
	return rc;
}

static void tcp_seq_stop(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2138
	struct tcp_iter_state *st = seq->private;
L
Linus Torvalds 已提交
2139 2140 2141 2142

	switch (st->state) {
	case TCP_SEQ_STATE_OPENREQ:
		if (v) {
2143 2144
			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
2145 2146 2147
		}
	case TCP_SEQ_STATE_LISTENING:
		if (v != SEQ_START_TOKEN)
2148
			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
L
Linus Torvalds 已提交
2149 2150 2151
		break;
	case TCP_SEQ_STATE_ESTABLISHED:
		if (v)
2152
			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
L
Linus Torvalds 已提交
2153 2154 2155 2156
		break;
	}
}

2157
int tcp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2158
{
A
Al Viro 已提交
2159
	struct tcp_seq_afinfo *afinfo = PDE_DATA(inode);
L
Linus Torvalds 已提交
2160
	struct tcp_iter_state *s;
2161
	int err;
L
Linus Torvalds 已提交
2162

2163 2164 2165 2166
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			  sizeof(struct tcp_iter_state));
	if (err < 0)
		return err;
2167

2168
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2169
	s->family		= afinfo->family;
S
stephen hemminger 已提交
2170
	s->last_pos		= 0;
2171 2172
	return 0;
}
2173
EXPORT_SYMBOL(tcp_seq_open);
2174

2175
int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2176 2177 2178 2179
{
	int rc = 0;
	struct proc_dir_entry *p;

2180 2181 2182 2183
	afinfo->seq_ops.start		= tcp_seq_start;
	afinfo->seq_ops.next		= tcp_seq_next;
	afinfo->seq_ops.stop		= tcp_seq_stop;

2184
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2185
			     afinfo->seq_fops, afinfo);
2186
	if (!p)
L
Linus Torvalds 已提交
2187 2188 2189
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2190
EXPORT_SYMBOL(tcp_proc_register);
L
Linus Torvalds 已提交
2191

2192
void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2193
{
2194
	remove_proc_entry(afinfo->name, net->proc_net);
L
Linus Torvalds 已提交
2195
}
E
Eric Dumazet 已提交
2196
EXPORT_SYMBOL(tcp_proc_unregister);
L
Linus Torvalds 已提交
2197

2198
static void get_openreq4(const struct sock *sk, const struct request_sock *req,
2199
			 struct seq_file *f, int i, kuid_t uid)
L
Linus Torvalds 已提交
2200
{
2201
	const struct inet_request_sock *ireq = inet_rsk(req);
2202
	long delta = req->expires - jiffies;
L
Linus Torvalds 已提交
2203

2204
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2205
		" %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
L
Linus Torvalds 已提交
2206
		i,
2207
		ireq->ir_loc_addr,
E
Eric Dumazet 已提交
2208
		ntohs(inet_sk(sk)->inet_sport),
2209 2210
		ireq->ir_rmt_addr,
		ntohs(ireq->ir_rmt_port),
L
Linus Torvalds 已提交
2211 2212 2213
		TCP_SYN_RECV,
		0, 0, /* could print option size, but that is af dependent. */
		1,    /* timers active (only the expire timer) */
2214
		jiffies_delta_to_clock_t(delta),
2215
		req->num_timeout,
2216
		from_kuid_munged(seq_user_ns(f), uid),
L
Linus Torvalds 已提交
2217 2218 2219
		0,  /* non standard timer */
		0, /* open_requests have no inode */
		atomic_read(&sk->sk_refcnt),
2220
		req);
L
Linus Torvalds 已提交
2221 2222
}

2223
static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
L
Linus Torvalds 已提交
2224 2225 2226
{
	int timer_active;
	unsigned long timer_expires;
2227
	const struct tcp_sock *tp = tcp_sk(sk);
2228
	const struct inet_connection_sock *icsk = inet_csk(sk);
2229
	const struct inet_sock *inet = inet_sk(sk);
2230
	struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
E
Eric Dumazet 已提交
2231 2232 2233 2234
	__be32 dest = inet->inet_daddr;
	__be32 src = inet->inet_rcv_saddr;
	__u16 destp = ntohs(inet->inet_dport);
	__u16 srcp = ntohs(inet->inet_sport);
2235
	int rx_queue;
L
Linus Torvalds 已提交
2236

N
Nandita Dukkipati 已提交
2237 2238 2239
	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
2240
		timer_active	= 1;
2241 2242
		timer_expires	= icsk->icsk_timeout;
	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
L
Linus Torvalds 已提交
2243
		timer_active	= 4;
2244
		timer_expires	= icsk->icsk_timeout;
2245
	} else if (timer_pending(&sk->sk_timer)) {
L
Linus Torvalds 已提交
2246
		timer_active	= 2;
2247
		timer_expires	= sk->sk_timer.expires;
L
Linus Torvalds 已提交
2248 2249 2250 2251 2252
	} else {
		timer_active	= 0;
		timer_expires = jiffies;
	}

2253 2254 2255 2256 2257 2258 2259 2260
	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);

2261
	seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
2262
			"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
2263
		i, src, srcp, dest, destp, sk->sk_state,
2264
		tp->write_seq - tp->snd_una,
2265
		rx_queue,
L
Linus Torvalds 已提交
2266
		timer_active,
2267
		jiffies_delta_to_clock_t(timer_expires - jiffies),
2268
		icsk->icsk_retransmits,
2269
		from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
2270
		icsk->icsk_probes_out,
2271 2272
		sock_i_ino(sk),
		atomic_read(&sk->sk_refcnt), sk,
2273 2274
		jiffies_to_clock_t(icsk->icsk_rto),
		jiffies_to_clock_t(icsk->icsk_ack.ato),
2275
		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
L
Linus Torvalds 已提交
2276
		tp->snd_cwnd,
2277 2278
		sk->sk_state == TCP_LISTEN ?
		    (fastopenq ? fastopenq->max_qlen : 0) :
2279
		    (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
L
Linus Torvalds 已提交
2280 2281
}

2282
static void get_timewait4_sock(const struct inet_timewait_sock *tw,
2283
			       struct seq_file *f, int i)
L
Linus Torvalds 已提交
2284
{
2285
	__be32 dest, src;
L
Linus Torvalds 已提交
2286
	__u16 destp, srcp;
2287
	s32 delta = tw->tw_ttd - inet_tw_time_stamp();
L
Linus Torvalds 已提交
2288 2289 2290 2291 2292 2293

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

2294
	seq_printf(f, "%4d: %08X:%04X %08X:%04X"
2295
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
L
Linus Torvalds 已提交
2296
		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
2297
		3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
2298
		atomic_read(&tw->tw_refcnt), tw);
L
Linus Torvalds 已提交
2299 2300 2301 2302 2303 2304
}

#define TMPSZ 150

static int tcp4_seq_show(struct seq_file *seq, void *v)
{
J
Jianjun Kong 已提交
2305
	struct tcp_iter_state *st;
E
Eric Dumazet 已提交
2306
	struct sock *sk = v;
L
Linus Torvalds 已提交
2307

2308
	seq_setwidth(seq, TMPSZ - 1);
L
Linus Torvalds 已提交
2309
	if (v == SEQ_START_TOKEN) {
2310
		seq_puts(seq, "  sl  local_address rem_address   st tx_queue "
L
Linus Torvalds 已提交
2311 2312 2313 2314 2315 2316 2317 2318 2319
			   "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
2320
		if (sk->sk_state == TCP_TIME_WAIT)
2321
			get_timewait4_sock(v, seq, st->num);
E
Eric Dumazet 已提交
2322
		else
2323
			get_tcp4_sock(v, seq, st->num);
L
Linus Torvalds 已提交
2324 2325
		break;
	case TCP_SEQ_STATE_OPENREQ:
2326
		get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid);
L
Linus Torvalds 已提交
2327 2328 2329
		break;
	}
out:
2330
	seq_pad(seq, '\n');
L
Linus Torvalds 已提交
2331 2332 2333
	return 0;
}

2334 2335 2336 2337 2338 2339 2340 2341
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
2342 2343 2344
static struct tcp_seq_afinfo tcp4_seq_afinfo = {
	.name		= "tcp",
	.family		= AF_INET,
2345
	.seq_fops	= &tcp_afinfo_seq_fops,
2346 2347 2348
	.seq_ops	= {
		.show		= tcp4_seq_show,
	},
L
Linus Torvalds 已提交
2349 2350
};

2351
static int __net_init tcp4_proc_init_net(struct net *net)
2352 2353 2354 2355
{
	return tcp_proc_register(net, &tcp4_seq_afinfo);
}

2356
static void __net_exit tcp4_proc_exit_net(struct net *net)
2357 2358 2359 2360 2361 2362 2363 2364 2365
{
	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
2366 2367
int __init tcp4_proc_init(void)
{
2368
	return register_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2369 2370 2371 2372
}

void tcp4_proc_exit(void)
{
2373
	unregister_pernet_subsys(&tcp4_net_ops);
L
Linus Torvalds 已提交
2374 2375 2376 2377 2378 2379 2380 2381 2382
}
#endif /* CONFIG_PROC_FS */

struct proto tcp_prot = {
	.name			= "TCP",
	.owner			= THIS_MODULE,
	.close			= tcp_close,
	.connect		= tcp_v4_connect,
	.disconnect		= tcp_disconnect,
2383
	.accept			= inet_csk_accept,
L
Linus Torvalds 已提交
2384 2385 2386 2387 2388 2389 2390
	.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,
2391 2392
	.sendmsg		= tcp_sendmsg,
	.sendpage		= tcp_sendpage,
L
Linus Torvalds 已提交
2393
	.backlog_rcv		= tcp_v4_do_rcv,
E
Eric Dumazet 已提交
2394
	.release_cb		= tcp_release_cb,
2395 2396 2397
	.hash			= inet_hash,
	.unhash			= inet_unhash,
	.get_port		= inet_csk_get_port,
L
Linus Torvalds 已提交
2398
	.enter_memory_pressure	= tcp_enter_memory_pressure,
2399
	.stream_memory_free	= tcp_stream_memory_free,
L
Linus Torvalds 已提交
2400
	.sockets_allocated	= &tcp_sockets_allocated,
2401
	.orphan_count		= &tcp_orphan_count,
L
Linus Torvalds 已提交
2402 2403
	.memory_allocated	= &tcp_memory_allocated,
	.memory_pressure	= &tcp_memory_pressure,
2404
	.sysctl_mem		= sysctl_tcp_mem,
L
Linus Torvalds 已提交
2405 2406 2407 2408
	.sysctl_wmem		= sysctl_tcp_wmem,
	.sysctl_rmem		= sysctl_tcp_rmem,
	.max_header		= MAX_TCP_HEADER,
	.obj_size		= sizeof(struct tcp_sock),
2409
	.slab_flags		= SLAB_DESTROY_BY_RCU,
2410
	.twsk_prot		= &tcp_timewait_sock_ops,
2411
	.rsk_prot		= &tcp_request_sock_ops,
2412
	.h.hashinfo		= &tcp_hashinfo,
2413
	.no_autobind		= true,
2414 2415 2416 2417
#ifdef CONFIG_COMPAT
	.compat_setsockopt	= compat_tcp_setsockopt,
	.compat_getsockopt	= compat_tcp_getsockopt,
#endif
A
Andrew Morton 已提交
2418
#ifdef CONFIG_MEMCG_KMEM
G
Glauber Costa 已提交
2419 2420 2421 2422
	.init_cgroup		= tcp_init_cgroup,
	.destroy_cgroup		= tcp_destroy_cgroup,
	.proto_cgroup		= tcp_proto_cgroup,
#endif
L
Linus Torvalds 已提交
2423
};
E
Eric Dumazet 已提交
2424
EXPORT_SYMBOL(tcp_prot);
L
Linus Torvalds 已提交
2425

2426 2427
static int __net_init tcp_sk_init(struct net *net)
{
2428
	net->ipv4.sysctl_tcp_ecn = 2;
2429
	return 0;
2430 2431 2432 2433
}

static void __net_exit tcp_sk_exit(struct net *net)
{
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Eric W. Biederman 已提交
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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);
2439 2440 2441
}

static struct pernet_operations __net_initdata tcp_sk_ops = {
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Eric W. Biederman 已提交
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       .init	   = tcp_sk_init,
       .exit	   = tcp_sk_exit,
       .exit_batch = tcp_sk_exit_batch,
2445 2446
};

2447
void __init tcp_v4_init(void)
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Linus Torvalds 已提交
2448
{
2449
	inet_hashinfo_init(&tcp_hashinfo);
2450
	if (register_pernet_subsys(&tcp_sk_ops))
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Linus Torvalds 已提交
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		panic("Failed to create the TCP control socket.\n");
}