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path: root/kernel/drivers/acpi/acpica/uthex.c
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/******************************************************************************
 *
 * Module Name: uthex -- Hex/ASCII support functions
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2015, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include "accommon.h"

#define _COMPONENT          ACPI_COMPILER
ACPI_MODULE_NAME("uthex")

/* Hex to ASCII conversion table */
static char acpi_gbl_hex_to_ascii[] = {
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
	    'E', 'F'
};

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_hex_to_ascii_char
 *
 * PARAMETERS:  integer             - Contains the hex digit
 *              position            - bit position of the digit within the
 *                                    integer (multiple of 4)
 *
 * RETURN:      The converted Ascii character
 *
 * DESCRIPTION: Convert a hex digit to an Ascii character
 *
 ******************************************************************************/

char acpi_ut_hex_to_ascii_char(u64 integer, u32 position)
{

	return (acpi_gbl_hex_to_ascii[(integer >> position) & 0xF]);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ut_ascii_char_to_hex
 *
 * PARAMETERS:  hex_char                - Hex character in Ascii
 *
 * RETURN:      The binary value of the ascii/hex character
 *
 * DESCRIPTION: Perform ascii-to-hex translation
 *
 ******************************************************************************/

u8 acpi_ut_ascii_char_to_hex(int hex_char)
{

	if (hex_char <= 0x39) {
		return ((u8)(hex_char - 0x30));
	}

	if (hex_char <= 0x46) {
		return ((u8)(hex_char - 0x37));
	}

	return ((u8)(hex_char - 0x57));
}
='#n638'>638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978
/*
 * 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.
 *
 *		Support for INET connection oriented protocols.
 *
 * Authors:	See the TCP sources
 *
 *		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.
 */

#include <linux/module.h>
#include <linux/jhash.h>

#include <net/inet_connection_sock.h>
#include <net/inet_hashtables.h>
#include <net/inet_timewait_sock.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/tcp_states.h>
#include <net/xfrm.h>
#include <net/tcp.h>

#ifdef INET_CSK_DEBUG
const char inet_csk_timer_bug_msg[] = "inet_csk BUG: unknown timer value\n";
EXPORT_SYMBOL(inet_csk_timer_bug_msg);
#endif

void inet_get_local_port_range(struct net *net, int *low, int *high)
{
	unsigned int seq;

	do {
		seq = read_seqbegin(&net->ipv4.ip_local_ports.lock);

		*low = net->ipv4.ip_local_ports.range[0];
		*high = net->ipv4.ip_local_ports.range[1];
	} while (read_seqretry(&net->ipv4.ip_local_ports.lock, seq));
}
EXPORT_SYMBOL(inet_get_local_port_range);

int inet_csk_bind_conflict(const struct sock *sk,
			   const struct inet_bind_bucket *tb, bool relax)
{
	struct sock *sk2;
	int reuse = sk->sk_reuse;
	int reuseport = sk->sk_reuseport;
	kuid_t uid = sock_i_uid((struct sock *)sk);

	/*
	 * Unlike other sk lookup places we do not check
	 * for sk_net here, since _all_ the socks listed
	 * in tb->owners list belong to the same net - the
	 * one this bucket belongs to.
	 */

	sk_for_each_bound(sk2, &tb->owners) {
		if (sk != sk2 &&
		    !inet_v6_ipv6only(sk2) &&
		    (!sk->sk_bound_dev_if ||
		     !sk2->sk_bound_dev_if ||
		     sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
			if ((!reuse || !sk2->sk_reuse ||
			    sk2->sk_state == TCP_LISTEN) &&
			    (!reuseport || !sk2->sk_reuseport ||
			    (sk2->sk_state != TCP_TIME_WAIT &&
			     !uid_eq(uid, sock_i_uid(sk2))))) {

				if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
				    sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
					break;
			}
			if (!relax && reuse && sk2->sk_reuse &&
			    sk2->sk_state != TCP_LISTEN) {

				if (!sk2->sk_rcv_saddr || !sk->sk_rcv_saddr ||
				    sk2->sk_rcv_saddr == sk->sk_rcv_saddr)
					break;
			}
		}
	}
	return sk2 != NULL;
}
EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);

/* Obtain a reference to a local port for the given sock,
 * if snum is zero it means select any available local port.
 */
int inet_csk_get_port(struct sock *sk, unsigned short snum)
{
	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
	struct inet_bind_hashbucket *head;
	struct inet_bind_bucket *tb;
	int ret, attempts = 5;
	struct net *net = sock_net(sk);
	int smallest_size = -1, smallest_rover;
	kuid_t uid = sock_i_uid(sk);

	local_bh_disable();
	if (!snum) {
		int remaining, rover, low, high;

again:
		inet_get_local_port_range(net, &low, &high);
		remaining = (high - low) + 1;
		smallest_rover = rover = prandom_u32() % remaining + low;

		smallest_size = -1;
		do {
			if (inet_is_local_reserved_port(net, rover))
				goto next_nolock;
			head = &hashinfo->bhash[inet_bhashfn(net, rover,
					hashinfo->bhash_size)];
			spin_lock(&head->lock);
			inet_bind_bucket_for_each(tb, &head->chain)
				if (net_eq(ib_net(tb), net) && tb->port == rover) {
					if (((tb->fastreuse > 0 &&
					      sk->sk_reuse &&
					      sk->sk_state != TCP_LISTEN) ||
					     (tb->fastreuseport > 0 &&
					      sk->sk_reuseport &&
					      uid_eq(tb->fastuid, uid))) &&
					    (tb->num_owners < smallest_size || smallest_size == -1)) {
						smallest_size = tb->num_owners;
						smallest_rover = rover;
						if (atomic_read(&hashinfo->bsockets) > (high - low) + 1 &&
						    !inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
							snum = smallest_rover;
							goto tb_found;
						}
					}
					if (!inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, false)) {
						snum = rover;
						goto tb_found;
					}
					goto next;
				}
			break;
		next:
			spin_unlock(&head->lock);
		next_nolock:
			if (++rover > high)
				rover = low;
		} while (--remaining > 0);

		/* Exhausted local port range during search?  It is not
		 * possible for us to be holding one of the bind hash
		 * locks if this test triggers, because if 'remaining'
		 * drops to zero, we broke out of the do/while loop at
		 * the top level, not from the 'break;' statement.
		 */
		ret = 1;
		if (remaining <= 0) {
			if (smallest_size != -1) {
				snum = smallest_rover;
				goto have_snum;
			}
			goto fail;
		}
		/* OK, here is the one we will use.  HEAD is
		 * non-NULL and we hold it's mutex.
		 */
		snum = rover;
	} else {
have_snum:
		head = &hashinfo->bhash[inet_bhashfn(net, snum,
				hashinfo->bhash_size)];
		spin_lock(&head->lock);
		inet_bind_bucket_for_each(tb, &head->chain)
			if (net_eq(ib_net(tb), net) && tb->port == snum)
				goto tb_found;
	}
	tb = NULL;
	goto tb_not_found;
tb_found:
	if (!hlist_empty(&tb->owners)) {
		if (sk->sk_reuse == SK_FORCE_REUSE)
			goto success;

		if (((tb->fastreuse > 0 &&
		      sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
		     (tb->fastreuseport > 0 &&
		      sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
		    smallest_size == -1) {
			goto success;
		} else {
			ret = 1;
			if (inet_csk(sk)->icsk_af_ops->bind_conflict(sk, tb, true)) {
				if (((sk->sk_reuse && sk->sk_state != TCP_LISTEN) ||
				     (tb->fastreuseport > 0 &&
				      sk->sk_reuseport && uid_eq(tb->fastuid, uid))) &&
				    smallest_size != -1 && --attempts >= 0) {
					spin_unlock(&head->lock);
					goto again;
				}

				goto fail_unlock;
			}
		}
	}
tb_not_found:
	ret = 1;
	if (!tb && (tb = inet_bind_bucket_create(hashinfo->bind_bucket_cachep,
					net, head, snum)) == NULL)
		goto fail_unlock;
	if (hlist_empty(&tb->owners)) {
		if (sk->sk_reuse && sk->sk_state != TCP_LISTEN)
			tb->fastreuse = 1;
		else
			tb->fastreuse = 0;
		if (sk->sk_reuseport) {
			tb->fastreuseport = 1;
			tb->fastuid = uid;
		} else
			tb->fastreuseport = 0;
	} else {
		if (tb->fastreuse &&
		    (!sk->sk_reuse || sk->sk_state == TCP_LISTEN))
			tb->fastreuse = 0;
		if (tb->fastreuseport &&
		    (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid)))
			tb->fastreuseport = 0;
	}
success:
	if (!inet_csk(sk)->icsk_bind_hash)
		inet_bind_hash(sk, tb, snum);
	WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);
	ret = 0;

fail_unlock:
	spin_unlock(&head->lock);
fail:
	local_bh_enable();
	return ret;
}
EXPORT_SYMBOL_GPL(inet_csk_get_port);

/*
 * Wait for an incoming connection, avoid race conditions. This must be called
 * with the socket locked.
 */
static int inet_csk_wait_for_connect(struct sock *sk, long timeo)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	DEFINE_WAIT(wait);
	int err;

	/*
	 * True wake-one mechanism for incoming connections: only
	 * one process gets woken up, not the 'whole herd'.
	 * Since we do not 'race & poll' for established sockets
	 * anymore, the common case will execute the loop only once.
	 *
	 * Subtle issue: "add_wait_queue_exclusive()" will be added
	 * after any current non-exclusive waiters, and we know that
	 * it will always _stay_ after any new non-exclusive waiters
	 * because all non-exclusive waiters are added at the
	 * beginning of the wait-queue. As such, it's ok to "drop"
	 * our exclusiveness temporarily when we get woken up without
	 * having to remove and re-insert us on the wait queue.
	 */
	for (;;) {
		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
					  TASK_INTERRUPTIBLE);
		release_sock(sk);
		if (reqsk_queue_empty(&icsk->icsk_accept_queue))
			timeo = schedule_timeout(timeo);
		sched_annotate_sleep();
		lock_sock(sk);
		err = 0;
		if (!reqsk_queue_empty(&icsk->icsk_accept_queue))
			break;
		err = -EINVAL;
		if (sk->sk_state != TCP_LISTEN)
			break;
		err = sock_intr_errno(timeo);
		if (signal_pending(current))
			break;
		err = -EAGAIN;
		if (!timeo)
			break;
	}
	finish_wait(sk_sleep(sk), &wait);
	return err;
}

/*
 * This will accept the next outstanding connection.
 */
struct sock *inet_csk_accept(struct sock *sk, int flags, int *err)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
	struct request_sock *req;
	struct sock *newsk;
	int error;

	lock_sock(sk);

	/* We need to make sure that this socket is listening,
	 * and that it has something pending.
	 */
	error = -EINVAL;
	if (sk->sk_state != TCP_LISTEN)
		goto out_err;

	/* Find already established connection */
	if (reqsk_queue_empty(queue)) {
		long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);

		/* If this is a non blocking socket don't sleep */
		error = -EAGAIN;
		if (!timeo)
			goto out_err;

		error = inet_csk_wait_for_connect(sk, timeo);
		if (error)
			goto out_err;
	}
	req = reqsk_queue_remove(queue);
	newsk = req->sk;

	sk_acceptq_removed(sk);
	if (sk->sk_protocol == IPPROTO_TCP &&
	    tcp_rsk(req)->tfo_listener &&
	    queue->fastopenq) {
		spin_lock_bh(&queue->fastopenq->lock);
		if (tcp_rsk(req)->tfo_listener) {
			/* We are still waiting for the final ACK from 3WHS
			 * so can't free req now. Instead, we set req->sk to
			 * NULL to signify that the child socket is taken
			 * so reqsk_fastopen_remove() will free the req
			 * when 3WHS finishes (or is aborted).
			 */
			req->sk = NULL;
			req = NULL;
		}
		spin_unlock_bh(&queue->fastopenq->lock);
	}
out:
	release_sock(sk);
	if (req)
		reqsk_put(req);
	return newsk;
out_err:
	newsk = NULL;
	req = NULL;
	*err = error;
	goto out;
}
EXPORT_SYMBOL(inet_csk_accept);

/*
 * Using different timers for retransmit, delayed acks and probes
 * We may wish use just one timer maintaining a list of expire jiffies
 * to optimize.
 */
void inet_csk_init_xmit_timers(struct sock *sk,
			       void (*retransmit_handler)(unsigned long),
			       void (*delack_handler)(unsigned long),
			       void (*keepalive_handler)(unsigned long))
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	setup_timer(&icsk->icsk_retransmit_timer, retransmit_handler,
			(unsigned long)sk);
	setup_timer(&icsk->icsk_delack_timer, delack_handler,
			(unsigned long)sk);
	setup_timer(&sk->sk_timer, keepalive_handler, (unsigned long)sk);
	icsk->icsk_pending = icsk->icsk_ack.pending = 0;
}
EXPORT_SYMBOL(inet_csk_init_xmit_timers);

void inet_csk_clear_xmit_timers(struct sock *sk)
{
	struct inet_connection_sock *icsk = inet_csk(sk);

	icsk->icsk_pending = icsk->icsk_ack.pending = icsk->icsk_ack.blocked = 0;

	sk_stop_timer(sk, &icsk->icsk_retransmit_timer);
	sk_stop_timer(sk, &icsk->icsk_delack_timer);
	sk_stop_timer(sk, &sk->sk_timer);
}
EXPORT_SYMBOL(inet_csk_clear_xmit_timers);

void inet_csk_delete_keepalive_timer(struct sock *sk)
{
	sk_stop_timer(sk, &sk->sk_timer);
}
EXPORT_SYMBOL(inet_csk_delete_keepalive_timer);

void inet_csk_reset_keepalive_timer(struct sock *sk, unsigned long len)
{
	sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
}
EXPORT_SYMBOL(inet_csk_reset_keepalive_timer);

struct dst_entry *inet_csk_route_req(struct sock *sk,
				     struct flowi4 *fl4,
				     const struct request_sock *req)
{
	const struct inet_request_sock *ireq = inet_rsk(req);
	struct net *net = read_pnet(&ireq->ireq_net);
	struct ip_options_rcu *opt = ireq->opt;
	struct rtable *rt;

	flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
			   RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
			   sk->sk_protocol, inet_sk_flowi_flags(sk),
			   (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
			   ireq->ir_loc_addr, ireq->ir_rmt_port,
			   htons(ireq->ir_num));
	security_req_classify_flow(req, flowi4_to_flowi(fl4));
	rt = ip_route_output_flow(net, fl4, sk);
	if (IS_ERR(rt))
		goto no_route;
	if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
		goto route_err;
	return &rt->dst;

route_err:
	ip_rt_put(rt);
no_route:
	IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
	return NULL;
}
EXPORT_SYMBOL_GPL(inet_csk_route_req);

struct dst_entry *inet_csk_route_child_sock(struct sock *sk,
					    struct sock *newsk,
					    const struct request_sock *req)
{
	const struct inet_request_sock *ireq = inet_rsk(req);
	struct net *net = read_pnet(&ireq->ireq_net);
	struct inet_sock *newinet = inet_sk(newsk);
	struct ip_options_rcu *opt;
	struct flowi4 *fl4;
	struct rtable *rt;

	fl4 = &newinet->cork.fl.u.ip4;

	rcu_read_lock();
	opt = rcu_dereference(newinet->inet_opt);
	flowi4_init_output(fl4, ireq->ir_iif, ireq->ir_mark,
			   RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
			   sk->sk_protocol, inet_sk_flowi_flags(sk),
			   (opt && opt->opt.srr) ? opt->opt.faddr : ireq->ir_rmt_addr,
			   ireq->ir_loc_addr, ireq->ir_rmt_port,
			   htons(ireq->ir_num));
	security_req_classify_flow(req, flowi4_to_flowi(fl4));
	rt = ip_route_output_flow(net, fl4, sk);
	if (IS_ERR(rt))
		goto no_route;
	if (opt && opt->opt.is_strictroute && rt->rt_uses_gateway)
		goto route_err;
	rcu_read_unlock();
	return &rt->dst;

route_err:
	ip_rt_put(rt);
no_route:
	rcu_read_unlock();
	IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
	return NULL;
}
EXPORT_SYMBOL_GPL(inet_csk_route_child_sock);

static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport,
				 const u32 rnd, const u32 synq_hsize)
{
	return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1);
}

#if IS_ENABLED(CONFIG_IPV6)
#define AF_INET_FAMILY(fam) ((fam) == AF_INET)
#else
#define AF_INET_FAMILY(fam) true
#endif

/* Note: this is temporary :
 * req sock will no longer be in listener hash table
*/
struct request_sock *inet_csk_search_req(struct sock *sk,
					 const __be16 rport,
					 const __be32 raddr,
					 const __be32 laddr)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
	struct request_sock *req;
	u32 hash = inet_synq_hash(raddr, rport, lopt->hash_rnd,
				  lopt->nr_table_entries);

	spin_lock(&icsk->icsk_accept_queue.syn_wait_lock);
	for (req = lopt->syn_table[hash]; req != NULL; req = req->dl_next) {
		const struct inet_request_sock *ireq = inet_rsk(req);

		if (ireq->ir_rmt_port == rport &&
		    ireq->ir_rmt_addr == raddr &&
		    ireq->ir_loc_addr == laddr &&
		    AF_INET_FAMILY(req->rsk_ops->family)) {
			atomic_inc(&req->rsk_refcnt);
			WARN_ON(req->sk);
			break;
		}
	}
	spin_unlock(&icsk->icsk_accept_queue.syn_wait_lock);

	return req;
}
EXPORT_SYMBOL_GPL(inet_csk_search_req);

void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
				   unsigned long timeout)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt;
	const u32 h = inet_synq_hash(inet_rsk(req)->ir_rmt_addr,
				     inet_rsk(req)->ir_rmt_port,
				     lopt->hash_rnd, lopt->nr_table_entries);

	reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout);
	inet_csk_reqsk_queue_added(sk, timeout);
}
EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add);

/* Only thing we need from tcp.h */
extern int sysctl_tcp_synack_retries;


/* Decide when to expire the request and when to resend SYN-ACK */
static inline void syn_ack_recalc(struct request_sock *req, const int thresh,
				  const int max_retries,
				  const u8 rskq_defer_accept,
				  int *expire, int *resend)
{
	if (!rskq_defer_accept) {
		*expire = req->num_timeout >= thresh;
		*resend = 1;
		return;
	}
	*expire = req->num_timeout >= thresh &&
		  (!inet_rsk(req)->acked || req->num_timeout >= max_retries);
	/*
	 * Do not resend while waiting for data after ACK,
	 * start to resend on end of deferring period to give
	 * last chance for data or ACK to create established socket.
	 */
	*resend = !inet_rsk(req)->acked ||
		  req->num_timeout >= rskq_defer_accept - 1;
}

int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req)
{
	int err = req->rsk_ops->rtx_syn_ack(parent, req);

	if (!err)
		req->num_retrans++;
	return err;
}
EXPORT_SYMBOL(inet_rtx_syn_ack);

/* return true if req was found in the syn_table[] */
static bool reqsk_queue_unlink(struct request_sock_queue *queue,
			       struct request_sock *req)
{
	struct listen_sock *lopt = queue->listen_opt;
	struct request_sock **prev;
	bool found = false;

	spin_lock(&queue->syn_wait_lock);

	for (prev = &lopt->syn_table[req->rsk_hash]; *prev != NULL;
	     prev = &(*prev)->dl_next) {
		if (*prev == req) {
			*prev = req->dl_next;
			found = true;
			break;
		}
	}

	spin_unlock(&queue->syn_wait_lock);
	if (del_timer_sync(&req->rsk_timer))
		reqsk_put(req);
	return found;
}

void inet_csk_reqsk_queue_drop(struct sock *sk, struct request_sock *req)
{
	if (reqsk_queue_unlink(&inet_csk(sk)->icsk_accept_queue, req)) {
		reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
		reqsk_put(req);
	}
}
EXPORT_SYMBOL(inet_csk_reqsk_queue_drop);

static void reqsk_timer_handler(unsigned long data)
{
	struct request_sock *req = (struct request_sock *)data;
	struct sock *sk_listener = req->rsk_listener;
	struct inet_connection_sock *icsk = inet_csk(sk_listener);
	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
	struct listen_sock *lopt = queue->listen_opt;
	int qlen, expire = 0, resend = 0;
	int max_retries, thresh;
	u8 defer_accept;

	if (sk_listener->sk_state != TCP_LISTEN || !lopt) {
		reqsk_put(req);
		return;
	}

	max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries;
	thresh = max_retries;
	/* Normally all the openreqs are young and become mature
	 * (i.e. converted to established socket) for first timeout.
	 * If synack was not acknowledged for 1 second, it means
	 * one of the following things: synack was lost, ack was lost,
	 * rtt is high or nobody planned to ack (i.e. synflood).
	 * When server is a bit loaded, queue is populated with old
	 * open requests, reducing effective size of queue.
	 * When server is well loaded, queue size reduces to zero
	 * after several minutes of work. It is not synflood,
	 * it is normal operation. The solution is pruning
	 * too old entries overriding normal timeout, when
	 * situation becomes dangerous.
	 *
	 * Essentially, we reserve half of room for young
	 * embrions; and abort old ones without pity, if old
	 * ones are about to clog our table.
	 */
	qlen = listen_sock_qlen(lopt);
	if (qlen >> (lopt->max_qlen_log - 1)) {
		int young = listen_sock_young(lopt) << 1;

		while (thresh > 2) {
			if (qlen < young)
				break;
			thresh--;
			young <<= 1;
		}
	}
	defer_accept = READ_ONCE(queue->rskq_defer_accept);
	if (defer_accept)
		max_retries = defer_accept;
	syn_ack_recalc(req, thresh, max_retries, defer_accept,
		       &expire, &resend);
	req->rsk_ops->syn_ack_timeout(req);
	if (!expire &&
	    (!resend ||
	     !inet_rtx_syn_ack(sk_listener, req) ||
	     inet_rsk(req)->acked)) {
		unsigned long timeo;

		if (req->num_timeout++ == 0)
			atomic_inc(&lopt->young_dec);
		timeo = min(TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX);
		mod_timer_pinned(&req->rsk_timer, jiffies + timeo);
		return;
	}
	inet_csk_reqsk_queue_drop(sk_listener, req);
	reqsk_put(req);
}

void reqsk_queue_hash_req(struct request_sock_queue *queue,
			  u32 hash, struct request_sock *req,
			  unsigned long timeout)
{
	struct listen_sock *lopt = queue->listen_opt;

	req->num_retrans = 0;
	req->num_timeout = 0;
	req->sk = NULL;

	/* before letting lookups find us, make sure all req fields
	 * are committed to memory and refcnt initialized.
	 */
	smp_wmb();
	atomic_set(&req->rsk_refcnt, 2);
	setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req);
	req->rsk_hash = hash;

	spin_lock(&queue->syn_wait_lock);
	req->dl_next = lopt->syn_table[hash];
	lopt->syn_table[hash] = req;
	spin_unlock(&queue->syn_wait_lock);

	mod_timer_pinned(&req->rsk_timer, jiffies + timeout);
}
EXPORT_SYMBOL(reqsk_queue_hash_req);

/**
 *	inet_csk_clone_lock - clone an inet socket, and lock its clone
 *	@sk: the socket to clone
 *	@req: request_sock
 *	@priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
 *
 *	Caller must unlock socket even in error path (bh_unlock_sock(newsk))
 */
struct sock *inet_csk_clone_lock(const struct sock *sk,
				 const struct request_sock *req,
				 const gfp_t priority)
{
	struct sock *newsk = sk_clone_lock(sk, priority);

	if (newsk) {
		struct inet_connection_sock *newicsk = inet_csk(newsk);

		newsk->sk_state = TCP_SYN_RECV;
		newicsk->icsk_bind_hash = NULL;

		inet_sk(newsk)->inet_dport = inet_rsk(req)->ir_rmt_port;
		inet_sk(newsk)->inet_num = inet_rsk(req)->ir_num;
		inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
		newsk->sk_write_space = sk_stream_write_space;

		newsk->sk_mark = inet_rsk(req)->ir_mark;
		atomic64_set(&newsk->sk_cookie,
			     atomic64_read(&inet_rsk(req)->ir_cookie));

		newicsk->icsk_retransmits = 0;
		newicsk->icsk_backoff	  = 0;
		newicsk->icsk_probes_out  = 0;

		/* Deinitialize accept_queue to trap illegal accesses. */
		memset(&newicsk->icsk_accept_queue, 0, sizeof(newicsk->icsk_accept_queue));

		security_inet_csk_clone(newsk, req);
	}
	return newsk;
}
EXPORT_SYMBOL_GPL(inet_csk_clone_lock);

/*
 * At this point, there should be no process reference to this
 * socket, and thus no user references at all.  Therefore we
 * can assume the socket waitqueue is inactive and nobody will
 * try to jump onto it.
 */
void inet_csk_destroy_sock(struct sock *sk)
{
	WARN_ON(sk->sk_state != TCP_CLOSE);
	WARN_ON(!sock_flag(sk, SOCK_DEAD));

	/* It cannot be in hash table! */
	WARN_ON(!sk_unhashed(sk));

	/* If it has not 0 inet_sk(sk)->inet_num, it must be bound */
	WARN_ON(inet_sk(sk)->inet_num && !inet_csk(sk)->icsk_bind_hash);

	sk->sk_prot->destroy(sk);

	sk_stream_kill_queues(sk);

	xfrm_sk_free_policy(sk);

	sk_refcnt_debug_release(sk);

	percpu_counter_dec(sk->sk_prot->orphan_count);
	sock_put(sk);
}
EXPORT_SYMBOL(inet_csk_destroy_sock);

/* This function allows to force a closure of a socket after the call to
 * tcp/dccp_create_openreq_child().
 */
void inet_csk_prepare_forced_close(struct sock *sk)
	__releases(&sk->sk_lock.slock)
{
	/* sk_clone_lock locked the socket and set refcnt to 2 */
	bh_unlock_sock(sk);
	sock_put(sk);

	/* The below has to be done to allow calling inet_csk_destroy_sock */
	sock_set_flag(sk, SOCK_DEAD);
	percpu_counter_inc(sk->sk_prot->orphan_count);
	inet_sk(sk)->inet_num = 0;
}
EXPORT_SYMBOL(inet_csk_prepare_forced_close);

int inet_csk_listen_start(struct sock *sk, const int nr_table_entries)
{
	struct inet_sock *inet = inet_sk(sk);
	struct inet_connection_sock *icsk = inet_csk(sk);
	int rc = reqsk_queue_alloc(&icsk->icsk_accept_queue, nr_table_entries);

	if (rc != 0)
		return rc;

	sk->sk_max_ack_backlog = 0;
	sk->sk_ack_backlog = 0;
	inet_csk_delack_init(sk);

	/* There is race window here: we announce ourselves listening,
	 * but this transition is still not validated by get_port().
	 * It is OK, because this socket enters to hash table only
	 * after validation is complete.
	 */
	sk->sk_state = TCP_LISTEN;
	if (!sk->sk_prot->get_port(sk, inet->inet_num)) {
		inet->inet_sport = htons(inet->inet_num);

		sk_dst_reset(sk);
		sk->sk_prot->hash(sk);

		return 0;
	}

	sk->sk_state = TCP_CLOSE;
	__reqsk_queue_destroy(&icsk->icsk_accept_queue);
	return -EADDRINUSE;
}
EXPORT_SYMBOL_GPL(inet_csk_listen_start);

/*
 *	This routine closes sockets which have been at least partially
 *	opened, but not yet accepted.
 */
void inet_csk_listen_stop(struct sock *sk)
{
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct request_sock_queue *queue = &icsk->icsk_accept_queue;
	struct request_sock *acc_req;
	struct request_sock *req;

	/* make all the listen_opt local to us */
	acc_req = reqsk_queue_yank_acceptq(queue);

	/* Following specs, it would be better either to send FIN
	 * (and enter FIN-WAIT-1, it is normal close)
	 * or to send active reset (abort).
	 * Certainly, it is pretty dangerous while synflood, but it is
	 * bad justification for our negligence 8)
	 * To be honest, we are not able to make either
	 * of the variants now.			--ANK
	 */
	reqsk_queue_destroy(queue);

	while ((req = acc_req) != NULL) {
		struct sock *child = req->sk;

		acc_req = req->dl_next;

		local_bh_disable();
		bh_lock_sock(child);
		WARN_ON(sock_owned_by_user(child));
		sock_hold(child);

		sk->sk_prot->disconnect(child, O_NONBLOCK);

		sock_orphan(child);

		percpu_counter_inc(sk->sk_prot->orphan_count);

		if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(req)->tfo_listener) {
			BUG_ON(tcp_sk(child)->fastopen_rsk != req);
			BUG_ON(sk != req->rsk_listener);

			/* Paranoid, to prevent race condition if
			 * an inbound pkt destined for child is
			 * blocked by sock lock in tcp_v4_rcv().
			 * Also to satisfy an assertion in
			 * tcp_v4_destroy_sock().
			 */
			tcp_sk(child)->fastopen_rsk = NULL;
		}
		inet_csk_destroy_sock(child);

		bh_unlock_sock(child);
		local_bh_enable();
		sock_put(child);

		sk_acceptq_removed(sk);
		reqsk_put(req);
	}
	if (queue->fastopenq) {
		/* Free all the reqs queued in rskq_rst_head. */
		spin_lock_bh(&queue->fastopenq->lock);
		acc_req = queue->fastopenq->rskq_rst_head;
		queue->fastopenq->rskq_rst_head = NULL;
		spin_unlock_bh(&queue->fastopenq->lock);
		while ((req = acc_req) != NULL) {
			acc_req = req->dl_next;
			reqsk_put(req);
		}
	}
	WARN_ON(sk->sk_ack_backlog);
}
EXPORT_SYMBOL_GPL(inet_csk_listen_stop);

void inet_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr)
{
	struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
	const struct inet_sock *inet = inet_sk(sk);

	sin->sin_family		= AF_INET;
	sin->sin_addr.s_addr	= inet->inet_daddr;
	sin->sin_port		= inet->inet_dport;
}
EXPORT_SYMBOL_GPL(inet_csk_addr2sockaddr);

#ifdef CONFIG_COMPAT
int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
			       char __user *optval, int __user *optlen)
{
	const struct inet_connection_sock *icsk = inet_csk(sk);

	if (icsk->icsk_af_ops->compat_getsockopt)
		return icsk->icsk_af_ops->compat_getsockopt(sk, level, optname,
							    optval, optlen);
	return icsk->icsk_af_ops->getsockopt(sk, level, optname,
					     optval, optlen);
}
EXPORT_SYMBOL_GPL(inet_csk_compat_getsockopt);

int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
			       char __user *optval, unsigned int optlen)
{
	const struct inet_connection_sock *icsk = inet_csk(sk);

	if (icsk->icsk_af_ops->compat_setsockopt)
		return icsk->icsk_af_ops->compat_setsockopt(sk, level, optname,
							    optval, optlen);
	return icsk->icsk_af_ops->setsockopt(sk, level, optname,
					     optval, optlen);
}
EXPORT_SYMBOL_GPL(inet_csk_compat_setsockopt);
#endif

static struct dst_entry *inet_csk_rebuild_route(struct sock *sk, struct flowi *fl)
{
	const struct inet_sock *inet = inet_sk(sk);
	const struct ip_options_rcu *inet_opt;
	__be32 daddr = inet->inet_daddr;
	struct flowi4 *fl4;
	struct rtable *rt;

	rcu_read_lock();
	inet_opt = rcu_dereference(inet->inet_opt);
	if (inet_opt && inet_opt->opt.srr)
		daddr = inet_opt->opt.faddr;
	fl4 = &fl->u.ip4;
	rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr,
				   inet->inet_saddr, inet->inet_dport,
				   inet->inet_sport, sk->sk_protocol,
				   RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
	if (IS_ERR(rt))
		rt = NULL;
	if (rt)
		sk_setup_caps(sk, &rt->dst);
	rcu_read_unlock();

	return &rt->dst;
}

struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu)
{
	struct dst_entry *dst = __sk_dst_check(sk, 0);
	struct inet_sock *inet = inet_sk(sk);

	if (!dst) {
		dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
		if (!dst)
			goto out;
	}
	dst->ops->update_pmtu(dst, sk, NULL, mtu);

	dst = __sk_dst_check(sk, 0);
	if (!dst)
		dst = inet_csk_rebuild_route(sk, &inet->cork.fl);
out:
	return dst;
}
EXPORT_SYMBOL_GPL(inet_csk_update_pmtu);