af_x25.c

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/*
 *  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
 *
 *  This module:
 *      This module 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.
 *
 *  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
 */

#include <linux/module.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched.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 <asm/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 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);

    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);
}

/*
 *  Kill all bound sockets on a dropped device.
 */
static void x25_kill_by_device(struct net_device *dev)
{
    struct sock *s;
    struct hlist_node *node;

    write_lock_bh(&x25_list_lock);

    sk_for_each(s, node, &x25_list)
        if (x25_sk(s)->neighbour && x25_sk(s)->neighbour->dev == dev)
            x25_disconnect(s, ENETUNREACH, 0, 0);

    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 = ptr;
    struct x25_neigh *nb;

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

    if (dev->type == ARPHRD_X25
#if IS_ENABLED(CONFIG_LLC)
     || dev->type == ARPHRD_ETHER
#endif
     ) {
        switch (event) {
        case NETDEV_UP:
            x25_link_device_up(dev);
            break;
        case NETDEV_GOING_DOWN:
            nb = x25_get_neigh(dev);
            if (nb) {
                x25_terminate_link(nb);
                x25_neigh_put(nb);
            }
            break;
        case NETDEV_DOWN:
            x25_kill_by_device(dev);
            x25_route_device_down(dev);
            x25_link_device_down(dev);
            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;
    struct hlist_node *node;

    read_lock_bh(&x25_list_lock);
    next_best = NULL;

    sk_for_each(s, node, &x25_list)
        if ((!strcmp(addr->x25_addr,
            x25_sk(s)->source_addr.x25_addr) ||
                !strcmp(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;
    struct hlist_node *node;

    sk_for_each(s, node, &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;

    read_lock_bh(&x25_list_lock);

    while ((sk = __x25_find_socket(lci, nb)) != NULL) {
        sock_put(sk);
        if (++lci == 4096) {
            lci = 0;
            break;
        }
    }

    read_unlock_bh(&x25_list_lock);
    return lci;
}

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

/*
 *  handler for deferred kills.
 */
static void x25_destroy_timer(unsigned long data)
{
    x25_destroy_socket_from_timer((struct sock *)data);
}

/*
 *  This is called from user mode and the timers. Thus it protects itself
 *  against interrupt 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;
        sk->sk_timer.data = (unsigned long)sk;
        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,
              char __user *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 (get_user(opt, (int __user *)optval))
        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;

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

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

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

    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 = -ENOBUFS;
    if ((sk = x25_alloc_socket(net)) == 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))) == NULL)
        goto out;

    x25 = x25_sk(sk);

    sk->sk_type        = osk->sk_type;
    sk->sk_priority    = 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;
    }

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

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

    if (!sock_flag(sk, SOCK_ZAPPED) ||
        addr_len != sizeof(struct sockaddr_x25) ||
        addr->sx25_family != AF_X25) {
        rc = -EINVAL;
        goto out;
    }

    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);
    x25_sk(sk)->source_addr = addr->sx25_addr;
    x25_insert_socket(sk);
    sock_reset_flag(sk, SOCK_ZAPPED);
    release_sock(sk);
    SOCK_DEBUG(sk, "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 = 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 *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;

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

    rc = -EINVAL;
    if (addr_len != sizeof(struct sockaddr_x25) ||
        addr->sx25_family != AF_X25)
        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_put_neigh;

    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_neigh_put(x25->neighbour);
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, int flags)
{
    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, 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->sk_ack_backlog--;
    newsock->state = SS_CONNECTED;
    rc = 0;
out2:
    release_sock(sk);
out:
    return rc;
}

static int x25_getname(struct socket *sock, struct sockaddr *uaddr,
               int *uaddr_len, 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;
    *uaddr_len = 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 facilties
     */

    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;
    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;
    }

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

    sk->sk_ack_backlog++;

    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, skb->len);
    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 kiocb *iocb, struct socket *sock,
               struct msghdr *msg, size_t len)
{
    struct sock *sk = sock->sk;
    struct x25_sock *x25 = x25_sk(sk);
    struct sockaddr_x25 *usx25 = (struct sockaddr_x25 *)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;
    }

    SOCK_DEBUG(sk, "x25_sendmsg: sendto: Addresses built.\n");

    /* Build a packet */
    SOCK_DEBUG(sk, "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
     */
    SOCK_DEBUG(sk, "x25_sendmsg: Copying user data\n");

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

    rc = memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, 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
     */
    SOCK_DEBUG(sk, "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;
    }

    SOCK_DEBUG(sk, "x25_sendmsg: Built header.\n");
    SOCK_DEBUG(sk, "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 kiocb *iocb, struct socket *sock,
               struct msghdr *msg, size_t size,
               int flags)
{
    struct sock *sk = sock->sk;
    struct x25_sock *x25 = x25_sk(sk);
    struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)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 & ~MSG_DONTWAIT,
                    flags & MSG_DONTWAIT, &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_iovec(skb, 0, msg->msg_iov, copied);
    if (rc)
        goto out_free_dgram;

    if (sx25) {
        sx25->sx25_family = AF_X25;
        sx25->sx25_addr   = x25->dest_addr;
    }

    msg->msg_namelen = sizeof(struct sockaddr_x25);

    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 SIOCGSTAMP:
        rc = -EINVAL;
        if (sk)
            rc = sock_get_timestamp(sk,
                        (struct timeval __user *)argp);
        break;
    case SIOCGSTAMPNS:
        rc = -EINVAL;
        if (sk)
            rc = sock_get_timestampns(sk,
                    (struct timespec __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.calling_ae == NULL)
            goto out_dtefac_release;
        if (dtefacs.called_len > X25_MAX_AE_LEN)
            goto out_dtefac_release;
        if (dtefacs.called_ae == NULL)
            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)
            break;
        clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
        release_sock(sk);
        rc = 0;
        break;
    }

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

    int rc = -ENOIOCTLCMD;

    switch(cmd) {
    case TIOCOUTQ:
    case TIOCINQ:
        rc = x25_ioctl(sock, cmd, (unsigned long)argp);
        break;
    case SIOCGSTAMP:
        rc = -EINVAL;
        if (sk)
            rc = compat_sock_get_timestamp(sk,
                    (struct timeval __user*)argp);
        break;
    case SIOCGSTAMPNS:
        rc = -EINVAL;
        if (sk)
            rc = compat_sock_get_timestampns(sk,
                    (struct timespec __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 = 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
    .listen =   x25_listen,
    .shutdown = sock_no_shutdown,
    .setsockopt =   x25_setsockopt,
    .getsockopt =   x25_getsockopt,
    .sendmsg =  x25_sendmsg,
    .recvmsg =  x25_recvmsg,
    .mmap =     sock_no_mmap,
    .sendpage = sock_no_sendpage,
};

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;
    struct hlist_node *node;

    write_lock_bh(&x25_list_lock);

    sk_for_each(s, node, &x25_list)
        if (x25_sk(s)->neighbour == nb)
            x25_disconnect(s, ENETUNREACH, 0, 0);

    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 = proto_register(&x25_proto, 0);

    if (rc != 0)
        goto out;

    rc = sock_register(&x25_family_ops);
    if (rc != 0)
        goto out_proto;

    dev_add_pack(&x25_packet_type);

    rc = register_netdevice_notifier(&x25_dev_notifier);
    if (rc != 0)
        goto out_sock;

    printk(KERN_INFO "X.25 for Linux Version 0.2\n");

    x25_register_sysctl();
    rc = x25_proc_init();
    if (rc != 0)
        goto out_dev;
out:
    return rc;
out_dev:
    unregister_netdevice_notifier(&x25_dev_notifier);
out_sock:
    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 <[email protected]>");
MODULE_DESCRIPTION("The X.25 Packet Layer network layer protocol");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_X25);