// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *      X.25 Packet Layer release 002
 *
 *      This is ALPHA test software. This code may break your machine,
 *      randomly fail to work with new releases, misbehave and/or generally
 *      screw up. It might even work.
 *
 *      This code REQUIRES 2.1.15 or higher
 *
 *      History
 *      X.25 001        Jonathan Naylor Started coding.
 *      X.25 002        Jonathan Naylor Centralised disconnect handling.
 *                                      New timer architecture.
 *      2000-03-11      Henner Eisen    MSG_EOR handling more POSIX compliant.
 *      2000-03-22      Daniela Squassoni Allowed disabling/enabling of
 *                                        facilities negotiation and increased
 *                                        the throughput upper limit.
 *      2000-08-27      Arnaldo C. Melo s/suser/capable/ + micro cleanups
 *      2000-09-04      Henner Eisen    Set sock->state in x25_accept().
 *                                      Fixed x25_output() related skb leakage.
 *      2000-10-02      Henner Eisen    Made x25_kick() single threaded per socket.
 *      2000-10-27      Henner Eisen    MSG_DONTWAIT for fragment allocation.
 *      2000-11-14      Henner Eisen    Closing datalink from NETDEV_GOING_DOWN
 *      2002-10-06      Arnaldo C. Melo Get rid of cli/sti, move proc stuff to
 *                                      x25_proc.c, using seq_file
 *      2005-04-02      Shaun Pereira   Selective sub address matching
 *                                      with call user data
 *      2005-04-15      Shaun Pereira   Fast select with no restriction on
 *                                      response
 */

#define pr_fmt(fmt) "X25: " fmt

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/termios.h>      /* For TIOCINQ/OUTQ */
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/compat.h>
#include <linux/ctype.h>

#include <net/x25.h>
#include <net/compat.h>

int sysctl_x25_restart_request_timeout = X25_DEFAULT_T20;
int sysctl_x25_call_request_timeout    = X25_DEFAULT_T21;
int sysctl_x25_reset_request_timeout   = X25_DEFAULT_T22;
int sysctl_x25_clear_request_timeout   = X25_DEFAULT_T23;
int sysctl_x25_ack_holdback_timeout    = X25_DEFAULT_T2;
int sysctl_x25_forward                 = 0;

HLIST_HEAD(x25_list);
DEFINE_RWLOCK(x25_list_lock);

static const struct proto_ops x25_proto_ops;

static const struct x25_address null_x25_address = {"               "};

#ifdef CONFIG_COMPAT
struct compat_x25_subscrip_struct {
        char device[200-sizeof(compat_ulong_t)];
        compat_ulong_t global_facil_mask;
        compat_uint_t extended;
};
#endif


int x25_parse_address_block(struct sk_buff *skb,
                struct x25_address *called_addr,
                struct x25_address *calling_addr)
{
        unsigned char len;
        int needed;
        int rc;

        if (!pskb_may_pull(skb, 1)) {
                /* packet has no address block */
                rc = 0;
                goto empty;
        }

        len = *skb->data;
        needed = 1 + ((len >> 4) + (len & 0x0f) + 1) / 2;

        if (!pskb_may_pull(skb, needed)) {
                /* packet is too short to hold the addresses it claims
                   to hold */
                rc = -1;
                goto empty;
        }

        return x25_addr_ntoa(skb->data, called_addr, calling_addr);

empty:
        *called_addr->x25_addr = 0;
        *calling_addr->x25_addr = 0;

        return rc;
}


int x25_addr_ntoa(unsigned char *p, struct x25_address *called_addr,
                  struct x25_address *calling_addr)
{
        unsigned int called_len, calling_len;
        char *called, *calling;
        unsigned int i;

        called_len  = (*p >> 0) & 0x0F;
        calling_len = (*p >> 4) & 0x0F;

        called  = called_addr->x25_addr;
        calling = calling_addr->x25_addr;
        p++;

        for (i = 0; i < (called_len + calling_len); i++) {
                if (i < called_len) {
                        if (i % 2 != 0) {
                                *called++ = ((*p >> 0) & 0x0F) + '0';
                                p++;
                        } else {
                                *called++ = ((*p >> 4) & 0x0F) + '0';
                        }
                } else {
                        if (i % 2 != 0) {
                                *calling++ = ((*p >> 0) & 0x0F) + '0';
                                p++;
                        } else {
                                *calling++ = ((*p >> 4) & 0x0F) + '0';
                        }
                }
        }

        *called = *calling = '\0';

        return 1 + (called_len + calling_len + 1) / 2;
}

int x25_addr_aton(unsigned char *p, struct x25_address *called_addr,
                  struct x25_address *calling_addr)
{
        unsigned int called_len, calling_len;
        char *called, *calling;
        int i;

        called  = called_addr->x25_addr;
        calling = calling_addr->x25_addr;

        called_len  = strlen(called);
        calling_len = strlen(calling);

        *p++ = (calling_len << 4) | (called_len << 0);

        for (i = 0; i < (called_len + calling_len); i++) {
                if (i < called_len) {
                        if (i % 2 != 0) {
                                *p |= (*called++ - '0') << 0;
                                p++;
                        } else {
                                *p = 0x00;
                                *p |= (*called++ - '0') << 4;
                        }
                } else {
                        if (i % 2 != 0) {
                                *p |= (*calling++ - '0') << 0;
                                p++;
                        } else {
                                *p = 0x00;
                                *p |= (*calling++ - '0') << 4;
                        }
                }
        }

        return 1 + (called_len + calling_len + 1) / 2;
}

/*
 *      Socket removal during an interrupt is now safe.
 */
static void x25_remove_socket(struct sock *sk)
{
        write_lock_bh(&x25_list_lock);
        sk_del_node_init(sk);
        write_unlock_bh(&x25_list_lock);
}

/*
 *      Handle device status changes.
 */
static int x25_device_event(struct notifier_block *this, unsigned long event,
                            void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
        struct x25_neigh *nb;

        if (!net_eq(dev_net(dev), &init_net))
                return NOTIFY_DONE;

        if (dev->type == ARPHRD_X25) {
                switch (event) {
                case NETDEV_REGISTER:
                case NETDEV_POST_TYPE_CHANGE:
                        x25_link_device_up(dev);
                        break;
                case NETDEV_DOWN:
                        nb = x25_get_neigh(dev);
                        if (nb) {
                                x25_link_terminated(nb);
                                x25_neigh_put(nb);
                        }
                        x25_route_device_down(dev);
                        break;
                case NETDEV_PRE_TYPE_CHANGE:
                case NETDEV_UNREGISTER:
                        x25_link_device_down(dev);
                        break;
                case NETDEV_CHANGE:
                        if (!netif_carrier_ok(dev)) {
                                nb = x25_get_neigh(dev);
                                if (nb) {
                                        x25_link_terminated(nb);
                                        x25_neigh_put(nb);
                                }
                        }
                        break;
                }
        }

        return NOTIFY_DONE;
}

/*
 *      Add a socket to the bound sockets list.
 */
static void x25_insert_socket(struct sock *sk)
{
        write_lock_bh(&x25_list_lock);
        sk_add_node(sk, &x25_list);
        write_unlock_bh(&x25_list_lock);
}

/*
 *      Find a socket that wants to accept the Call Request we just
 *      received. Check the full list for an address/cud match.
 *      If no cuds match return the next_best thing, an address match.
 *      Note: if a listening socket has cud set it must only get calls
 *      with matching cud.
 */
static struct sock *x25_find_listener(struct x25_address *addr,
                                        struct sk_buff *skb)
{
        struct sock *s;
        struct sock *next_best;

        read_lock_bh(&x25_list_lock);
        next_best = NULL;

        sk_for_each(s, &x25_list)
                if ((!strcmp(addr->x25_addr,
                        x25_sk(s)->source_addr.x25_addr) ||
                                !strcmp(x25_sk(s)->source_addr.x25_addr,
                                        null_x25_address.x25_addr)) &&
                                        s->sk_state == TCP_LISTEN) {
                        /*
                         * Found a listening socket, now check the incoming
                         * call user data vs this sockets call user data
                         */
                        if (x25_sk(s)->cudmatchlength > 0 &&
                                skb->len >= x25_sk(s)->cudmatchlength) {
                                if((memcmp(x25_sk(s)->calluserdata.cuddata,
                                        skb->data,
                                        x25_sk(s)->cudmatchlength)) == 0) {
                                        sock_hold(s);
                                        goto found;
                                 }
                        } else
                                next_best = s;
                }
        if (next_best) {
                s = next_best;
                sock_hold(s);
                goto found;
        }
        s = NULL;
found:
        read_unlock_bh(&x25_list_lock);
        return s;
}

/*
 *      Find a connected X.25 socket given my LCI and neighbour.
 */
static struct sock *__x25_find_socket(unsigned int lci, struct x25_neigh *nb)
{
        struct sock *s;

        sk_for_each(s, &x25_list)
                if (x25_sk(s)->lci == lci && x25_sk(s)->neighbour == nb) {
                        sock_hold(s);
                        goto found;
                }
        s = NULL;
found:
        return s;
}

struct sock *x25_find_socket(unsigned int lci, struct x25_neigh *nb)
{
        struct sock *s;

        read_lock_bh(&x25_list_lock);
        s = __x25_find_socket(lci, nb);
        read_unlock_bh(&x25_list_lock);
        return s;
}

/*
 *      Find a unique LCI for a given device.
 */
static unsigned int x25_new_lci(struct x25_neigh *nb)
{
        unsigned int lci = 1;
        struct sock *sk;

        while ((sk = x25_find_socket(lci, nb)) != NULL) {
                sock_put(sk);
                if (++lci == 4096) {
                        lci = 0;
                        break;
                }
                cond_resched();
        }

        return lci;
}

/*
 *      Deferred destroy.
 */
static void __x25_destroy_socket(struct sock *);

/*
 *      handler for deferred kills.
 */
static void x25_destroy_timer(struct timer_list *t)
{
        struct sock *sk = timer_container_of(sk, t, sk_timer);

        x25_destroy_socket_from_timer(sk);
}

/*
 *      This is called from user mode and the timers. Thus it protects itself
 *      against interrupting users but doesn't worry about being called during
 *      work. Once it is removed from the queue no interrupt or bottom half
 *      will touch it and we are (fairly 8-) ) safe.
 *      Not static as it's used by the timer
 */
static void __x25_destroy_socket(struct sock *sk)
{
        struct sk_buff *skb;

        x25_stop_heartbeat(sk);
        x25_stop_timer(sk);

        x25_remove_socket(sk);
        x25_clear_queues(sk);           /* Flush the queues */

        while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
                if (skb->sk != sk) {            /* A pending connection */
                        /*
                         * Queue the unaccepted socket for death
                         */
                        skb->sk->sk_state = TCP_LISTEN;
                        sock_set_flag(skb->sk, SOCK_DEAD);
                        x25_start_heartbeat(skb->sk);
                        x25_sk(skb->sk)->state = X25_STATE_0;
                }

                kfree_skb(skb);
        }

        if (sk_has_allocations(sk)) {
                /* Defer: outstanding buffers */
                sk->sk_timer.expires  = jiffies + 10 * HZ;
                sk->sk_timer.function = x25_destroy_timer;
                add_timer(&sk->sk_timer);
        } else {
                /* drop last reference so sock_put will free */
                __sock_put(sk);
        }
}

void x25_destroy_socket_from_timer(struct sock *sk)
{
        sock_hold(sk);
        bh_lock_sock(sk);
        __x25_destroy_socket(sk);
        bh_unlock_sock(sk);
        sock_put(sk);
}

/*
 *      Handling for system calls applied via the various interfaces to a
 *      X.25 socket object.
 */

static int x25_setsockopt(struct socket *sock, int level, int optname,
                          sockptr_t optval, unsigned int optlen)
{
        int opt;
        struct sock *sk = sock->sk;
        int rc = -ENOPROTOOPT;

        if (level != SOL_X25 || optname != X25_QBITINCL)
                goto out;

        rc = -EINVAL;
        if (optlen < sizeof(int))
                goto out;

        rc = -EFAULT;
        if (copy_from_sockptr(&opt, optval, sizeof(int)))
                goto out;

        if (opt)
                set_bit(X25_Q_BIT_FLAG, &x25_sk(sk)->flags);
        else
                clear_bit(X25_Q_BIT_FLAG, &x25_sk(sk)->flags);
        rc = 0;
out:
        return rc;
}

static int x25_getsockopt(struct socket *sock, int level, int optname,
                          char __user *optval, int __user *optlen)
{
        struct sock *sk = sock->sk;
        int val, len, rc = -ENOPROTOOPT;

        if (level != SOL_X25 || optname != X25_QBITINCL)
                goto out;

        rc = -EFAULT;
        if (get_user(len, optlen))
                goto out;

        rc = -EINVAL;
        if (len < 0)
                goto out;

        len = min_t(unsigned int, len, sizeof(int));

        rc = -EFAULT;
        if (put_user(len, optlen))
                goto out;

        val = test_bit(X25_Q_BIT_FLAG, &x25_sk(sk)->flags);
        rc = copy_to_user(optval, &val, len) ? -EFAULT : 0;
out:
        return rc;
}

static int x25_listen(struct socket *sock, int backlog)
{
        struct sock *sk = sock->sk;
        int rc = -EOPNOTSUPP;

        lock_sock(sk);
        if (sock->state != SS_UNCONNECTED) {
                rc = -EINVAL;
                release_sock(sk);
                return rc;
        }

        if (sk->sk_state != TCP_LISTEN) {
                memset(&x25_sk(sk)->dest_addr, 0, X25_ADDR_LEN);
                sk->sk_max_ack_backlog = backlog;
                sk->sk_state           = TCP_LISTEN;
                rc = 0;
        }
        release_sock(sk);

        return rc;
}

static struct proto x25_proto = {
        .name     = "X25",
        .owner    = THIS_MODULE,
        .obj_size = sizeof(struct x25_sock),
};

static struct sock *x25_alloc_socket(struct net *net, int kern)
{
        struct x25_sock *x25;
        struct sock *sk = sk_alloc(net, AF_X25, GFP_ATOMIC, &x25_proto, kern);

        if (!sk)
                goto out;

        sock_init_data(NULL, sk);

        x25 = x25_sk(sk);
        skb_queue_head_init(&x25->ack_queue);
        skb_queue_head_init(&x25->fragment_queue);
        skb_queue_head_init(&x25->interrupt_in_queue);
        skb_queue_head_init(&x25->interrupt_out_queue);
out:
        return sk;
}

static int x25_create(struct net *net, struct socket *sock, int protocol,
                      int kern)
{
        struct sock *sk;
        struct x25_sock *x25;
        int rc = -EAFNOSUPPORT;

        if (!net_eq(net, &init_net))
                goto out;

        rc = -ESOCKTNOSUPPORT;
        if (sock->type != SOCK_SEQPACKET)
                goto out;

        rc = -EINVAL;
        if (protocol)
                goto out;

        rc = -ENOMEM;
        if ((sk = x25_alloc_socket(net, kern)) == NULL)
                goto out;

        x25 = x25_sk(sk);

        sock_init_data(sock, sk);

        x25_init_timers(sk);

        sock->ops    = &x25_proto_ops;
        sk->sk_protocol = protocol;
        sk->sk_backlog_rcv = x25_backlog_rcv;

        x25->t21   = sysctl_x25_call_request_timeout;
        x25->t22   = sysctl_x25_reset_request_timeout;
        x25->t23   = sysctl_x25_clear_request_timeout;
        x25->t2    = sysctl_x25_ack_holdback_timeout;
        x25->state = X25_STATE_0;
        x25->cudmatchlength = 0;
        set_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);     /* normally no cud  */
                                                        /* on call accept   */

        x25->facilities.winsize_in  = X25_DEFAULT_WINDOW_SIZE;
        x25->facilities.winsize_out = X25_DEFAULT_WINDOW_SIZE;
        x25->facilities.pacsize_in  = X25_DEFAULT_PACKET_SIZE;
        x25->facilities.pacsize_out = X25_DEFAULT_PACKET_SIZE;
        x25->facilities.throughput  = 0;        /* by default don't negotiate
                                                   throughput */
        x25->facilities.reverse     = X25_DEFAULT_REVERSE;
        x25->dte_facilities.calling_len = 0;
        x25->dte_facilities.called_len = 0;
        memset(x25->dte_facilities.called_ae, '\0',
                        sizeof(x25->dte_facilities.called_ae));
        memset(x25->dte_facilities.calling_ae, '\0',
                        sizeof(x25->dte_facilities.calling_ae));

        rc = 0;
out:
        return rc;
}

static struct sock *x25_make_new(struct sock *osk)
{
        struct sock *sk = NULL;
        struct x25_sock *x25, *ox25;

        if (osk->sk_type != SOCK_SEQPACKET)
                goto out;

        if ((sk = x25_alloc_socket(sock_net(osk), 0)) == NULL)
                goto out;

        x25 = x25_sk(sk);

        sk->sk_type        = osk->sk_type;
        sk->sk_priority    = READ_ONCE(osk->sk_priority);
        sk->sk_protocol    = osk->sk_protocol;
        sk->sk_rcvbuf      = osk->sk_rcvbuf;
        sk->sk_sndbuf      = osk->sk_sndbuf;
        sk->sk_state       = TCP_ESTABLISHED;
        sk->sk_backlog_rcv = osk->sk_backlog_rcv;
        sock_copy_flags(sk, osk);

        ox25 = x25_sk(osk);
        x25->t21        = ox25->t21;
        x25->t22        = ox25->t22;
        x25->t23        = ox25->t23;
        x25->t2         = ox25->t2;
        x25->flags      = ox25->flags;
        x25->facilities = ox25->facilities;
        x25->dte_facilities = ox25->dte_facilities;
        x25->cudmatchlength = ox25->cudmatchlength;

        clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
        x25_init_timers(sk);
out:
        return sk;
}

static int x25_release(struct socket *sock)
{
        struct sock *sk = sock->sk;
        struct x25_sock *x25;

        if (!sk)
                return 0;

        x25 = x25_sk(sk);

        sock_hold(sk);
        lock_sock(sk);
        switch (x25->state) {

                case X25_STATE_0:
                case X25_STATE_2:
                        x25_disconnect(sk, 0, 0, 0);
                        __x25_destroy_socket(sk);
                        goto out;

                case X25_STATE_1:
                case X25_STATE_3:
                case X25_STATE_4:
                        x25_clear_queues(sk);
                        x25_write_internal(sk, X25_CLEAR_REQUEST);
                        x25_start_t23timer(sk);
                        x25->state = X25_STATE_2;
                        sk->sk_state    = TCP_CLOSE;
                        sk->sk_shutdown |= SEND_SHUTDOWN;
                        sk->sk_state_change(sk);
                        sock_set_flag(sk, SOCK_DEAD);
                        sock_set_flag(sk, SOCK_DESTROY);
                        break;

                case X25_STATE_5:
                        x25_write_internal(sk, X25_CLEAR_REQUEST);
                        x25_disconnect(sk, 0, 0, 0);
                        __x25_destroy_socket(sk);
                        goto out;
        }

        sock_orphan(sk);
out:
        release_sock(sk);
        sock_put(sk);
        return 0;
}

static int x25_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addr_len)
{
        struct sock *sk = sock->sk;
        struct sockaddr_x25 *addr = (struct sockaddr_x25 *)uaddr;
        int len, i, rc = 0;

        if (addr_len != sizeof(struct sockaddr_x25) ||
            addr->sx25_family != AF_X25 ||
            strnlen(addr->sx25_addr.x25_addr, X25_ADDR_LEN) == X25_ADDR_LEN) {
                rc = -EINVAL;
                goto out;
        }

        /* check for the null_x25_address */
        if (strcmp(addr->sx25_addr.x25_addr, null_x25_address.x25_addr)) {

                len = strlen(addr->sx25_addr.x25_addr);
                for (i = 0; i < len; i++) {
                        if (!isdigit(addr->sx25_addr.x25_addr[i])) {
                                rc = -EINVAL;
                                goto out;
                        }
                }
        }

        lock_sock(sk);
        if (sock_flag(sk, SOCK_ZAPPED)) {
                x25_sk(sk)->source_addr = addr->sx25_addr;
                x25_insert_socket(sk);
                sock_reset_flag(sk, SOCK_ZAPPED);
        } else {
                rc = -EINVAL;
        }
        release_sock(sk);
        net_dbg_ratelimited("x25_bind: socket is bound\n");
out:
        return rc;
}

static int x25_wait_for_connection_establishment(struct sock *sk)
{
        DECLARE_WAITQUEUE(wait, current);
        int rc;

        add_wait_queue_exclusive(sk_sleep(sk), &wait);
        for (;;) {
                __set_current_state(TASK_INTERRUPTIBLE);
                rc = -ERESTARTSYS;
                if (signal_pending(current))
                        break;
                rc = sock_error(sk);
                if (rc) {
                        sk->sk_socket->state = SS_UNCONNECTED;
                        break;
                }
                rc = -ENOTCONN;
                if (sk->sk_state == TCP_CLOSE) {
                        sk->sk_socket->state = SS_UNCONNECTED;
                        break;
                }
                rc = 0;
                if (sk->sk_state != TCP_ESTABLISHED) {
                        release_sock(sk);
                        schedule();
                        lock_sock(sk);
                } else
                        break;
        }
        __set_current_state(TASK_RUNNING);
        remove_wait_queue(sk_sleep(sk), &wait);
        return rc;
}

static int x25_connect(struct socket *sock, struct sockaddr_unsized *uaddr,
                       int addr_len, int flags)
{
        struct sock *sk = sock->sk;
        struct x25_sock *x25 = x25_sk(sk);
        struct sockaddr_x25 *addr = (struct sockaddr_x25 *)uaddr;
        struct x25_route *rt;
        int rc = 0;

        lock_sock(sk);
        if (sk->sk_state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
                sock->state = SS_CONNECTED;
                goto out; /* Connect completed during a ERESTARTSYS event */
        }

        rc = -ECONNREFUSED;
        if (sk->sk_state == TCP_CLOSE && sock->state == SS_CONNECTING) {
                sock->state = SS_UNCONNECTED;
                goto out;
        }

        rc = -EISCONN;  /* No reconnect on a seqpacket socket */
        if (sk->sk_state == TCP_ESTABLISHED)
                goto out;

        rc = -EALREADY; /* Do nothing if call is already in progress */
        if (sk->sk_state == TCP_SYN_SENT)
                goto out;

        sk->sk_state   = TCP_CLOSE;
        sock->state = SS_UNCONNECTED;

        rc = -EINVAL;
        if (addr_len != sizeof(struct sockaddr_x25) ||
            addr->sx25_family != AF_X25 ||
            strnlen(addr->sx25_addr.x25_addr, X25_ADDR_LEN) == X25_ADDR_LEN)
                goto out;

        rc = -ENETUNREACH;
        rt = x25_get_route(&addr->sx25_addr);
        if (!rt)
                goto out;

        x25->neighbour = x25_get_neigh(rt->dev);
        if (!x25->neighbour)
                goto out_put_route;

        x25_limit_facilities(&x25->facilities, x25->neighbour);

        x25->lci = x25_new_lci(x25->neighbour);
        if (!x25->lci)
                goto out_put_neigh;

        rc = -EINVAL;
        if (sock_flag(sk, SOCK_ZAPPED)) /* Must bind first - autobinding does not work */
                goto out_put_neigh;

        if (!strcmp(x25->source_addr.x25_addr, null_x25_address.x25_addr))
                memset(&x25->source_addr, '\0', X25_ADDR_LEN);

        x25->dest_addr = addr->sx25_addr;

        /* Move to connecting socket, start sending Connect Requests */
        sock->state   = SS_CONNECTING;
        sk->sk_state  = TCP_SYN_SENT;

        x25->state = X25_STATE_1;

        x25_write_internal(sk, X25_CALL_REQUEST);

        x25_start_heartbeat(sk);
        x25_start_t21timer(sk);

        /* Now the loop */
        rc = -EINPROGRESS;
        if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
                goto out;

        rc = x25_wait_for_connection_establishment(sk);
        if (rc)
                goto out_put_neigh;

        sock->state = SS_CONNECTED;
        rc = 0;
out_put_neigh:
        if (rc && x25->neighbour) {
                read_lock_bh(&x25_list_lock);
                x25_neigh_put(x25->neighbour);
                x25->neighbour = NULL;
                read_unlock_bh(&x25_list_lock);
                x25->state = X25_STATE_0;
        }
out_put_route:
        x25_route_put(rt);
out:
        release_sock(sk);
        return rc;
}

static int x25_wait_for_data(struct sock *sk, long timeout)
{
        DECLARE_WAITQUEUE(wait, current);
        int rc = 0;

        add_wait_queue_exclusive(sk_sleep(sk), &wait);
        for (;;) {
                __set_current_state(TASK_INTERRUPTIBLE);
                if (sk->sk_shutdown & RCV_SHUTDOWN)
                        break;
                rc = -ERESTARTSYS;
                if (signal_pending(current))
                        break;
                rc = -EAGAIN;
                if (!timeout)
                        break;
                rc = 0;
                if (skb_queue_empty(&sk->sk_receive_queue)) {
                        release_sock(sk);
                        timeout = schedule_timeout(timeout);
                        lock_sock(sk);
                } else
                        break;
        }
        __set_current_state(TASK_RUNNING);
        remove_wait_queue(sk_sleep(sk), &wait);
        return rc;
}

static int x25_accept(struct socket *sock, struct socket *newsock,
                      struct proto_accept_arg *arg)
{
        struct sock *sk = sock->sk;
        struct sock *newsk;
        struct sk_buff *skb;
        int rc = -EINVAL;

        if (!sk)
                goto out;

        rc = -EOPNOTSUPP;
        if (sk->sk_type != SOCK_SEQPACKET)
                goto out;

        lock_sock(sk);
        rc = -EINVAL;
        if (sk->sk_state != TCP_LISTEN)
                goto out2;

        rc = x25_wait_for_data(sk, READ_ONCE(sk->sk_rcvtimeo));
        if (rc)
                goto out2;
        skb = skb_dequeue(&sk->sk_receive_queue);
        rc = -EINVAL;
        if (!skb->sk)
                goto out2;
        newsk            = skb->sk;
        sock_graft(newsk, newsock);

        /* Now attach up the new socket */
        skb->sk = NULL;
        kfree_skb(skb);
        sk_acceptq_removed(sk);
        newsock->state = SS_CONNECTED;
        rc = 0;
out2:
        release_sock(sk);
out:
        return rc;
}

static int x25_getname(struct socket *sock, struct sockaddr *uaddr,
                       int peer)
{
        struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)uaddr;
        struct sock *sk = sock->sk;
        struct x25_sock *x25 = x25_sk(sk);
        int rc = 0;

        if (peer) {
                if (sk->sk_state != TCP_ESTABLISHED) {
                        rc = -ENOTCONN;
                        goto out;
                }
                sx25->sx25_addr = x25->dest_addr;
        } else
                sx25->sx25_addr = x25->source_addr;

        sx25->sx25_family = AF_X25;
        rc = sizeof(*sx25);

out:
        return rc;
}

int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb,
                        unsigned int lci)
{
        struct sock *sk;
        struct sock *make;
        struct x25_sock *makex25;
        struct x25_address source_addr, dest_addr;
        struct x25_facilities facilities;
        struct x25_dte_facilities dte_facilities;
        int len, addr_len, rc;

        /*
         *      Remove the LCI and frame type.
         */
        skb_pull(skb, X25_STD_MIN_LEN);

        /*
         *      Extract the X.25 addresses and convert them to ASCII strings,
         *      and remove them.
         *
         *      Address block is mandatory in call request packets
         */
        addr_len = x25_parse_address_block(skb, &source_addr, &dest_addr);
        if (addr_len <= 0)
                goto out_clear_request;
        skb_pull(skb, addr_len);

        /*
         *      Get the length of the facilities, skip past them for the moment
         *      get the call user data because this is needed to determine
         *      the correct listener
         *
         *      Facilities length is mandatory in call request packets
         */
        if (!pskb_may_pull(skb, 1))
                goto out_clear_request;
        len = skb->data[0] + 1;
        if (!pskb_may_pull(skb, len))
                goto out_clear_request;
        skb_pull(skb,len);

        /*
         *      Ensure that the amount of call user data is valid.
         */
        if (skb->len > X25_MAX_CUD_LEN)
                goto out_clear_request;

        /*
         *      Get all the call user data so it can be used in
         *      x25_find_listener and skb_copy_from_linear_data up ahead.
         */
        if (!pskb_may_pull(skb, skb->len))
                goto out_clear_request;

        /*
         *      Find a listener for the particular address/cud pair.
         */
        sk = x25_find_listener(&source_addr,skb);
        skb_push(skb,len);

        if (sk != NULL && sk_acceptq_is_full(sk)) {
                goto out_sock_put;
        }

        /*
         *      We dont have any listeners for this incoming call.
         *      Try forwarding it.
         */
        if (sk == NULL) {
                skb_push(skb, addr_len + X25_STD_MIN_LEN);
                if (sysctl_x25_forward &&
                                x25_forward_call(&dest_addr, nb, skb, lci) > 0)
                {
                        /* Call was forwarded, dont process it any more */
                        kfree_skb(skb);
                        rc = 1;
                        goto out;
                } else {
                        /* No listeners, can't forward, clear the call */
                        goto out_clear_request;
                }
        }

        /*
         *      Try to reach a compromise on the requested facilities.
         */
        len = x25_negotiate_facilities(skb, sk, &facilities, &dte_facilities);
        if (len == -1)
                goto out_sock_put;

        /*
         * current neighbour/link might impose additional limits
         * on certain facilities
         */

        x25_limit_facilities(&facilities, nb);

        /*
         *      Try to create a new socket.
         */
        make = x25_make_new(sk);
        if (!make)
                goto out_sock_put;

        /*
         *      Remove the facilities
         */
        skb_pull(skb, len);

        skb->sk     = make;
        make->sk_state = TCP_ESTABLISHED;

        makex25 = x25_sk(make);
        makex25->lci           = lci;
        makex25->dest_addr     = dest_addr;
        makex25->source_addr   = source_addr;
        x25_neigh_hold(nb);
        makex25->neighbour     = nb;
        makex25->facilities    = facilities;
        makex25->dte_facilities= dte_facilities;
        makex25->vc_facil_mask = x25_sk(sk)->vc_facil_mask;
        /* ensure no reverse facil on accept */
        makex25->vc_facil_mask &= ~X25_MASK_REVERSE;
        /* ensure no calling address extension on accept */
        makex25->vc_facil_mask &= ~X25_MASK_CALLING_AE;
        makex25->cudmatchlength = x25_sk(sk)->cudmatchlength;

        /* Normally all calls are accepted immediately */
        if (test_bit(X25_ACCPT_APPRV_FLAG, &makex25->flags)) {
                x25_write_internal(make, X25_CALL_ACCEPTED);
                makex25->state = X25_STATE_3;
        } else {
                makex25->state = X25_STATE_5;
        }

        /*
         *      Incoming Call User Data.
         */
        skb_copy_from_linear_data(skb, makex25->calluserdata.cuddata, skb->len);
        makex25->calluserdata.cudlength = skb->len;

        sk_acceptq_added(sk);

        x25_insert_socket(make);

        skb_queue_head(&sk->sk_receive_queue, skb);

        x25_start_heartbeat(make);

        if (!sock_flag(sk, SOCK_DEAD))
                sk->sk_data_ready(sk);
        rc = 1;
        sock_put(sk);
out:
        return rc;
out_sock_put:
        sock_put(sk);
out_clear_request:
        rc = 0;
        x25_transmit_clear_request(nb, lci, 0x01);
        goto out;
}

static int x25_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
        struct sock *sk = sock->sk;
        struct x25_sock *x25 = x25_sk(sk);
        DECLARE_SOCKADDR(struct sockaddr_x25 *, usx25, msg->msg_name);
        struct sockaddr_x25 sx25;
        struct sk_buff *skb;
        unsigned char *asmptr;
        int noblock = msg->msg_flags & MSG_DONTWAIT;
        size_t size;
        int qbit = 0, rc = -EINVAL;

        lock_sock(sk);
        if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_OOB|MSG_EOR|MSG_CMSG_COMPAT))
                goto out;

        /* we currently don't support segmented records at the user interface */
        if (!(msg->msg_flags & (MSG_EOR|MSG_OOB)))
                goto out;

        rc = -EADDRNOTAVAIL;
        if (sock_flag(sk, SOCK_ZAPPED))
                goto out;

        rc = -EPIPE;
        if (sk->sk_shutdown & SEND_SHUTDOWN) {
                send_sig(SIGPIPE, current, 0);
                goto out;
        }

        rc = -ENETUNREACH;
        if (!x25->neighbour)
                goto out;

        if (usx25) {
                rc = -EINVAL;
                if (msg->msg_namelen < sizeof(sx25))
                        goto out;
                memcpy(&sx25, usx25, sizeof(sx25));
                rc = -EISCONN;
                if (strcmp(x25->dest_addr.x25_addr, sx25.sx25_addr.x25_addr))
                        goto out;
                rc = -EINVAL;
                if (sx25.sx25_family != AF_X25)
                        goto out;
        } else {
                /*
                 *      FIXME 1003.1g - if the socket is like this because
                 *      it has become closed (not started closed) we ought
                 *      to SIGPIPE, EPIPE;
                 */
                rc = -ENOTCONN;
                if (sk->sk_state != TCP_ESTABLISHED)
                        goto out;

                sx25.sx25_family = AF_X25;
                sx25.sx25_addr   = x25->dest_addr;
        }

        /* Sanity check the packet size */
        if (len > 65535) {
                rc = -EMSGSIZE;
                goto out;
        }

        net_dbg_ratelimited("x25_sendmsg: sendto: Addresses built.\n");

        /* Build a packet */
        net_dbg_ratelimited("x25_sendmsg: sendto: building packet.\n");

        if ((msg->msg_flags & MSG_OOB) && len > 32)
                len = 32;

        size = len + X25_MAX_L2_LEN + X25_EXT_MIN_LEN;

        release_sock(sk);
        skb = sock_alloc_send_skb(sk, size, noblock, &rc);
        lock_sock(sk);
        if (!skb)
                goto out;
        X25_SKB_CB(skb)->flags = msg->msg_flags;

        skb_reserve(skb, X25_MAX_L2_LEN + X25_EXT_MIN_LEN);

        /*
         *      Put the data on the end
         */
        net_dbg_ratelimited("x25_sendmsg: Copying user data\n");

        skb_reset_transport_header(skb);
        skb_put(skb, len);

        rc = memcpy_from_msg(skb_transport_header(skb), msg, len);
        if (rc)
                goto out_kfree_skb;

        /*
         *      If the Q BIT Include socket option is in force, the first
         *      byte of the user data is the logical value of the Q Bit.
         */
        if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {
                if (!pskb_may_pull(skb, 1))
                        goto out_kfree_skb;

                qbit = skb->data[0];
                skb_pull(skb, 1);
        }

        /*
         *      Push down the X.25 header
         */
        net_dbg_ratelimited("x25_sendmsg: Building X.25 Header.\n");

        if (msg->msg_flags & MSG_OOB) {
                if (x25->neighbour->extended) {
                        asmptr    = skb_push(skb, X25_STD_MIN_LEN);
                        *asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_EXTSEQ;
                        *asmptr++ = (x25->lci >> 0) & 0xFF;
                        *asmptr++ = X25_INTERRUPT;
                } else {
                        asmptr    = skb_push(skb, X25_STD_MIN_LEN);
                        *asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_STDSEQ;
                        *asmptr++ = (x25->lci >> 0) & 0xFF;
                        *asmptr++ = X25_INTERRUPT;
                }
        } else {
                if (x25->neighbour->extended) {
                        /* Build an Extended X.25 header */
                        asmptr    = skb_push(skb, X25_EXT_MIN_LEN);
                        *asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_EXTSEQ;
                        *asmptr++ = (x25->lci >> 0) & 0xFF;
                        *asmptr++ = X25_DATA;
                        *asmptr++ = X25_DATA;
                } else {
                        /* Build an Standard X.25 header */
                        asmptr    = skb_push(skb, X25_STD_MIN_LEN);
                        *asmptr++ = ((x25->lci >> 8) & 0x0F) | X25_GFI_STDSEQ;
                        *asmptr++ = (x25->lci >> 0) & 0xFF;
                        *asmptr++ = X25_DATA;
                }

                if (qbit)
                        skb->data[0] |= X25_Q_BIT;
        }

        net_dbg_ratelimited("x25_sendmsg: Built header.\n");
        net_dbg_ratelimited("x25_sendmsg: Transmitting buffer\n");

        rc = -ENOTCONN;
        if (sk->sk_state != TCP_ESTABLISHED)
                goto out_kfree_skb;

        if (msg->msg_flags & MSG_OOB)
                skb_queue_tail(&x25->interrupt_out_queue, skb);
        else {
                rc = x25_output(sk, skb);
                len = rc;
                if (rc < 0)
                        kfree_skb(skb);
                else if (test_bit(X25_Q_BIT_FLAG, &x25->flags))
                        len++;
        }

        x25_kick(sk);
        rc = len;
out:
        release_sock(sk);
        return rc;
out_kfree_skb:
        kfree_skb(skb);
        goto out;
}


static int x25_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
                       int flags)
{
        struct sock *sk = sock->sk;
        struct x25_sock *x25 = x25_sk(sk);
        DECLARE_SOCKADDR(struct sockaddr_x25 *, sx25, msg->msg_name);
        size_t copied;
        int qbit, header_len;
        struct sk_buff *skb;
        unsigned char *asmptr;
        int rc = -ENOTCONN;

        lock_sock(sk);

        if (x25->neighbour == NULL)
                goto out;

        header_len = x25->neighbour->extended ?
                X25_EXT_MIN_LEN : X25_STD_MIN_LEN;

        /*
         * This works for seqpacket too. The receiver has ordered the queue for
         * us! We do one quick check first though
         */
        if (sk->sk_state != TCP_ESTABLISHED)
                goto out;

        if (flags & MSG_OOB) {
                rc = -EINVAL;
                if (sock_flag(sk, SOCK_URGINLINE) ||
                    !skb_peek(&x25->interrupt_in_queue))
                        goto out;

                skb = skb_dequeue(&x25->interrupt_in_queue);

                if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
                        goto out_free_dgram;

                skb_pull(skb, X25_STD_MIN_LEN);

                /*
                 *      No Q bit information on Interrupt data.
                 */
                if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {
                        asmptr  = skb_push(skb, 1);
                        *asmptr = 0x00;
                }

                msg->msg_flags |= MSG_OOB;
        } else {
                /* Now we can treat all alike */
                release_sock(sk);
                skb = skb_recv_datagram(sk, flags, &rc);
                lock_sock(sk);
                if (!skb)
                        goto out;

                if (!pskb_may_pull(skb, header_len))
                        goto out_free_dgram;

                qbit = (skb->data[0] & X25_Q_BIT) == X25_Q_BIT;

                skb_pull(skb, header_len);

                if (test_bit(X25_Q_BIT_FLAG, &x25->flags)) {
                        asmptr  = skb_push(skb, 1);
                        *asmptr = qbit;
                }
        }

        skb_reset_transport_header(skb);
        copied = skb->len;

        if (copied > size) {
                copied = size;
                msg->msg_flags |= MSG_TRUNC;
        }

        /* Currently, each datagram always contains a complete record */
        msg->msg_flags |= MSG_EOR;

        rc = skb_copy_datagram_msg(skb, 0, msg, copied);
        if (rc)
                goto out_free_dgram;

        if (sx25) {
                sx25->sx25_family = AF_X25;
                sx25->sx25_addr   = x25->dest_addr;
                msg->msg_namelen = sizeof(*sx25);
        }

        x25_check_rbuf(sk);
        rc = copied;
out_free_dgram:
        skb_free_datagram(sk, skb);
out:
        release_sock(sk);
        return rc;
}


static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        struct sock *sk = sock->sk;
        struct x25_sock *x25 = x25_sk(sk);
        void __user *argp = (void __user *)arg;
        int rc;

        switch (cmd) {
        case TIOCOUTQ: {
                int amount;

                amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
                if (amount < 0)
                        amount = 0;
                rc = put_user(amount, (unsigned int __user *)argp);
                break;
        }

        case TIOCINQ: {
                struct sk_buff *skb;
                int amount = 0;
                /*
                 * These two are safe on a single CPU system as
                 * only user tasks fiddle here
                 */
                lock_sock(sk);
                if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
                        amount = skb->len;
                release_sock(sk);
                rc = put_user(amount, (unsigned int __user *)argp);
                break;
        }

        case SIOCGIFADDR:
        case SIOCSIFADDR:
        case SIOCGIFDSTADDR:
        case SIOCSIFDSTADDR:
        case SIOCGIFBRDADDR:
        case SIOCSIFBRDADDR:
        case SIOCGIFNETMASK:
        case SIOCSIFNETMASK:
        case SIOCGIFMETRIC:
        case SIOCSIFMETRIC:
                rc = -EINVAL;
                break;
        case SIOCADDRT:
        case SIOCDELRT:
                rc = -EPERM;
                if (!capable(CAP_NET_ADMIN))
                        break;
                rc = x25_route_ioctl(cmd, argp);
                break;
        case SIOCX25GSUBSCRIP:
                rc = x25_subscr_ioctl(cmd, argp);
                break;
        case SIOCX25SSUBSCRIP:
                rc = -EPERM;
                if (!capable(CAP_NET_ADMIN))
                        break;
                rc = x25_subscr_ioctl(cmd, argp);
                break;
        case SIOCX25GFACILITIES: {
                lock_sock(sk);
                rc = copy_to_user(argp, &x25->facilities,
                                  sizeof(x25->facilities))
                        ? -EFAULT : 0;
                release_sock(sk);
                break;
        }

        case SIOCX25SFACILITIES: {
                struct x25_facilities facilities;
                rc = -EFAULT;
                if (copy_from_user(&facilities, argp, sizeof(facilities)))
                        break;
                rc = -EINVAL;
                lock_sock(sk);
                if (sk->sk_state != TCP_LISTEN &&
                    sk->sk_state != TCP_CLOSE)
                        goto out_fac_release;
                if (facilities.pacsize_in < X25_PS16 ||
                    facilities.pacsize_in > X25_PS4096)
                        goto out_fac_release;
                if (facilities.pacsize_out < X25_PS16 ||
                    facilities.pacsize_out > X25_PS4096)
                        goto out_fac_release;
                if (facilities.winsize_in < 1 ||
                    facilities.winsize_in > 127)
                        goto out_fac_release;
                if (facilities.throughput) {
                        int out = facilities.throughput & 0xf0;
                        int in  = facilities.throughput & 0x0f;
                        if (!out)
                                facilities.throughput |=
                                        X25_DEFAULT_THROUGHPUT << 4;
                        else if (out < 0x30 || out > 0xD0)
                                goto out_fac_release;
                        if (!in)
                                facilities.throughput |=
                                        X25_DEFAULT_THROUGHPUT;
                        else if (in < 0x03 || in > 0x0D)
                                goto out_fac_release;
                }
                if (facilities.reverse &&
                    (facilities.reverse & 0x81) != 0x81)
                        goto out_fac_release;
                x25->facilities = facilities;
                rc = 0;
out_fac_release:
                release_sock(sk);
                break;
        }

        case SIOCX25GDTEFACILITIES: {
                lock_sock(sk);
                rc = copy_to_user(argp, &x25->dte_facilities,
                                  sizeof(x25->dte_facilities));
                release_sock(sk);
                if (rc)
                        rc = -EFAULT;
                break;
        }

        case SIOCX25SDTEFACILITIES: {
                struct x25_dte_facilities dtefacs;
                rc = -EFAULT;
                if (copy_from_user(&dtefacs, argp, sizeof(dtefacs)))
                        break;
                rc = -EINVAL;
                lock_sock(sk);
                if (sk->sk_state != TCP_LISTEN &&
                    sk->sk_state != TCP_CLOSE)
                        goto out_dtefac_release;
                if (dtefacs.calling_len > X25_MAX_AE_LEN)
                        goto out_dtefac_release;
                if (dtefacs.called_len > X25_MAX_AE_LEN)
                        goto out_dtefac_release;
                x25->dte_facilities = dtefacs;
                rc = 0;
out_dtefac_release:
                release_sock(sk);
                break;
        }

        case SIOCX25GCALLUSERDATA: {
                lock_sock(sk);
                rc = copy_to_user(argp, &x25->calluserdata,
                                  sizeof(x25->calluserdata))
                        ? -EFAULT : 0;
                release_sock(sk);
                break;
        }

        case SIOCX25SCALLUSERDATA: {
                struct x25_calluserdata calluserdata;

                rc = -EFAULT;
                if (copy_from_user(&calluserdata, argp, sizeof(calluserdata)))
                        break;
                rc = -EINVAL;
                if (calluserdata.cudlength > X25_MAX_CUD_LEN)
                        break;
                lock_sock(sk);
                x25->calluserdata = calluserdata;
                release_sock(sk);
                rc = 0;
                break;
        }

        case SIOCX25GCAUSEDIAG: {
                lock_sock(sk);
                rc = copy_to_user(argp, &x25->causediag, sizeof(x25->causediag))
                        ? -EFAULT : 0;
                release_sock(sk);
                break;
        }

        case SIOCX25SCAUSEDIAG: {
                struct x25_causediag causediag;
                rc = -EFAULT;
                if (copy_from_user(&causediag, argp, sizeof(causediag)))
                        break;
                lock_sock(sk);
                x25->causediag = causediag;
                release_sock(sk);
                rc = 0;
                break;

        }

        case SIOCX25SCUDMATCHLEN: {
                struct x25_subaddr sub_addr;
                rc = -EINVAL;
                lock_sock(sk);
                if(sk->sk_state != TCP_CLOSE)
                        goto out_cud_release;
                rc = -EFAULT;
                if (copy_from_user(&sub_addr, argp,
                                   sizeof(sub_addr)))
                        goto out_cud_release;
                rc = -EINVAL;
                if (sub_addr.cudmatchlength > X25_MAX_CUD_LEN)
                        goto out_cud_release;
                x25->cudmatchlength = sub_addr.cudmatchlength;
                rc = 0;
out_cud_release:
                release_sock(sk);
                break;
        }

        case SIOCX25CALLACCPTAPPRV: {
                rc = -EINVAL;
                lock_sock(sk);
                if (sk->sk_state == TCP_CLOSE) {
                        clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
                        rc = 0;
                }
                release_sock(sk);
                break;
        }

        case SIOCX25SENDCALLACCPT:  {
                rc = -EINVAL;
                lock_sock(sk);
                if (sk->sk_state != TCP_ESTABLISHED)
                        goto out_sendcallaccpt_release;
                /* must call accptapprv above */
                if (test_bit(X25_ACCPT_APPRV_FLAG, &x25->flags))
                        goto out_sendcallaccpt_release;
                x25_write_internal(sk, X25_CALL_ACCEPTED);
                x25->state = X25_STATE_3;
                rc = 0;
out_sendcallaccpt_release:
                release_sock(sk);
                break;
        }

        default:
                rc = -ENOIOCTLCMD;
                break;
        }

        return rc;
}

static const struct net_proto_family x25_family_ops = {
        .family =       AF_X25,
        .create =       x25_create,
        .owner  =       THIS_MODULE,
};

#ifdef CONFIG_COMPAT
static int compat_x25_subscr_ioctl(unsigned int cmd,
                struct compat_x25_subscrip_struct __user *x25_subscr32)
{
        struct compat_x25_subscrip_struct x25_subscr;
        struct x25_neigh *nb;
        struct net_device *dev;
        int rc = -EINVAL;

        rc = -EFAULT;
        if (copy_from_user(&x25_subscr, x25_subscr32, sizeof(*x25_subscr32)))
                goto out;

        rc = -EINVAL;
        dev = x25_dev_get(x25_subscr.device);
        if (dev == NULL)
                goto out;

        nb = x25_get_neigh(dev);
        if (nb == NULL)
                goto out_dev_put;

        dev_put(dev);

        if (cmd == SIOCX25GSUBSCRIP) {
                read_lock_bh(&x25_neigh_list_lock);
                x25_subscr.extended = nb->extended;
                x25_subscr.global_facil_mask = nb->global_facil_mask;
                read_unlock_bh(&x25_neigh_list_lock);
                rc = copy_to_user(x25_subscr32, &x25_subscr,
                                sizeof(*x25_subscr32)) ? -EFAULT : 0;
        } else {
                rc = -EINVAL;
                if (x25_subscr.extended == 0 || x25_subscr.extended == 1) {
                        rc = 0;
                        write_lock_bh(&x25_neigh_list_lock);
                        nb->extended = x25_subscr.extended;
                        nb->global_facil_mask = x25_subscr.global_facil_mask;
                        write_unlock_bh(&x25_neigh_list_lock);
                }
        }
        x25_neigh_put(nb);
out:
        return rc;
out_dev_put:
        dev_put(dev);
        goto out;
}

static int compat_x25_ioctl(struct socket *sock, unsigned int cmd,
                                unsigned long arg)
{
        void __user *argp = compat_ptr(arg);
        int rc = -ENOIOCTLCMD;

        switch(cmd) {
        case TIOCOUTQ:
        case TIOCINQ:
                rc = x25_ioctl(sock, cmd, (unsigned long)argp);
                break;
        case SIOCGIFADDR:
        case SIOCSIFADDR:
        case SIOCGIFDSTADDR:
        case SIOCSIFDSTADDR:
        case SIOCGIFBRDADDR:
        case SIOCSIFBRDADDR:
        case SIOCGIFNETMASK:
        case SIOCSIFNETMASK:
        case SIOCGIFMETRIC:
        case SIOCSIFMETRIC:
                rc = -EINVAL;
                break;
        case SIOCADDRT:
        case SIOCDELRT:
                rc = -EPERM;
                if (!capable(CAP_NET_ADMIN))
                        break;
                rc = x25_route_ioctl(cmd, argp);
                break;
        case SIOCX25GSUBSCRIP:
                rc = compat_x25_subscr_ioctl(cmd, argp);
                break;
        case SIOCX25SSUBSCRIP:
                rc = -EPERM;
                if (!capable(CAP_NET_ADMIN))
                        break;
                rc = compat_x25_subscr_ioctl(cmd, argp);
                break;
        case SIOCX25GFACILITIES:
        case SIOCX25SFACILITIES:
        case SIOCX25GDTEFACILITIES:
        case SIOCX25SDTEFACILITIES:
        case SIOCX25GCALLUSERDATA:
        case SIOCX25SCALLUSERDATA:
        case SIOCX25GCAUSEDIAG:
        case SIOCX25SCAUSEDIAG:
        case SIOCX25SCUDMATCHLEN:
        case SIOCX25CALLACCPTAPPRV:
        case SIOCX25SENDCALLACCPT:
                rc = x25_ioctl(sock, cmd, (unsigned long)argp);
                break;
        default:
                rc = -ENOIOCTLCMD;
                break;
        }
        return rc;
}
#endif

static const struct proto_ops x25_proto_ops = {
        .family =       AF_X25,
        .owner =        THIS_MODULE,
        .release =      x25_release,
        .bind =         x25_bind,
        .connect =      x25_connect,
        .socketpair =   sock_no_socketpair,
        .accept =       x25_accept,
        .getname =      x25_getname,
        .poll =         datagram_poll,
        .ioctl =        x25_ioctl,
#ifdef CONFIG_COMPAT
        .compat_ioctl = compat_x25_ioctl,
#endif
        .gettstamp =    sock_gettstamp,
        .listen =       x25_listen,
        .shutdown =     sock_no_shutdown,
        .setsockopt =   x25_setsockopt,
        .getsockopt =   x25_getsockopt,
        .sendmsg =      x25_sendmsg,
        .recvmsg =      x25_recvmsg,
        .mmap =         sock_no_mmap,
};

static struct packet_type x25_packet_type __read_mostly = {
        .type = cpu_to_be16(ETH_P_X25),
        .func = x25_lapb_receive_frame,
};

static struct notifier_block x25_dev_notifier = {
        .notifier_call = x25_device_event,
};

void x25_kill_by_neigh(struct x25_neigh *nb)
{
        struct sock *s;

        write_lock_bh(&x25_list_lock);

        sk_for_each(s, &x25_list) {
                if (x25_sk(s)->neighbour == nb) {
                        write_unlock_bh(&x25_list_lock);
                        lock_sock(s);
                        x25_disconnect(s, ENETUNREACH, 0, 0);
                        release_sock(s);
                        write_lock_bh(&x25_list_lock);
                }
        }
        write_unlock_bh(&x25_list_lock);

        /* Remove any related forwards */
        x25_clear_forward_by_dev(nb->dev);
}

static int __init x25_init(void)
{
        int rc;

        rc = proto_register(&x25_proto, 0);
        if (rc)
                goto out;

        rc = sock_register(&x25_family_ops);
        if (rc)
                goto out_proto;

        dev_add_pack(&x25_packet_type);

        rc = register_netdevice_notifier(&x25_dev_notifier);
        if (rc)
                goto out_sock;

        rc = x25_register_sysctl();
        if (rc)
                goto out_dev;

        rc = x25_proc_init();
        if (rc)
                goto out_sysctl;

        pr_info("Linux Version 0.2\n");

out:
        return rc;
out_sysctl:
        x25_unregister_sysctl();
out_dev:
        unregister_netdevice_notifier(&x25_dev_notifier);
out_sock:
        dev_remove_pack(&x25_packet_type);
        sock_unregister(AF_X25);
out_proto:
        proto_unregister(&x25_proto);
        goto out;
}
module_init(x25_init);

static void __exit x25_exit(void)
{
        x25_proc_exit();
        x25_link_free();
        x25_route_free();

        x25_unregister_sysctl();

        unregister_netdevice_notifier(&x25_dev_notifier);

        dev_remove_pack(&x25_packet_type);

        sock_unregister(AF_X25);
        proto_unregister(&x25_proto);
}
module_exit(x25_exit);

MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The X.25 Packet Layer network layer protocol");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_X25);