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root/net/netrom/af_netrom.c

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DEFINITIONS

This source file includes following definitions.
  1. nr_set_lockdep_one
  2. nr_set_lockdep_key
  3. nr_remove_socket
  4. nr_kill_by_device
  5. nr_device_event
  6. nr_insert_socket
  7. nr_find_listener
  8. nr_find_socket
  9. nr_find_peer
  10. nr_find_next_circuit
  11. nr_destroy_timer
  12. nr_destroy_socket
  13. nr_setsockopt
  14. nr_getsockopt
  15. nr_listen
  16. nr_create
  17. nr_make_new
  18. nr_release
  19. nr_bind
  20. nr_connect
  21. nr_accept
  22. nr_getname
  23. nr_rx_frame
  24. nr_sendmsg
  25. nr_recvmsg
  26. nr_ioctl
  27. nr_info_start
  28. nr_info_next
  29. nr_info_stop
  30. nr_info_show
  31. nr_info_open
  32. nr_proto_init
  33. nr_exit

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 * Copyright Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
 * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk)
 */
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/stat.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/termios.h>      /* For TIOCINQ/OUTQ */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <net/netrom.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/ip.h>
#include <net/tcp_states.h>
#include <net/arp.h>
#include <linux/init.h>

static int nr_ndevs = 4;

int sysctl_netrom_default_path_quality            = NR_DEFAULT_QUAL;
int sysctl_netrom_obsolescence_count_initialiser  = NR_DEFAULT_OBS;
int sysctl_netrom_network_ttl_initialiser         = NR_DEFAULT_TTL;
int sysctl_netrom_transport_timeout               = NR_DEFAULT_T1;
int sysctl_netrom_transport_maximum_tries         = NR_DEFAULT_N2;
int sysctl_netrom_transport_acknowledge_delay     = NR_DEFAULT_T2;
int sysctl_netrom_transport_busy_delay            = NR_DEFAULT_T4;
int sysctl_netrom_transport_requested_window_size = NR_DEFAULT_WINDOW;
int sysctl_netrom_transport_no_activity_timeout   = NR_DEFAULT_IDLE;
int sysctl_netrom_routing_control                 = NR_DEFAULT_ROUTING;
int sysctl_netrom_link_fails_count                = NR_DEFAULT_FAILS;
int sysctl_netrom_reset_circuit                   = NR_DEFAULT_RESET;

static unsigned short circuit = 0x101;

static HLIST_HEAD(nr_list);
static DEFINE_SPINLOCK(nr_list_lock);

static const struct proto_ops nr_proto_ops;

/*
 * NETROM network devices are virtual network devices encapsulating NETROM
 * frames into AX.25 which will be sent through an AX.25 device, so form a
 * special "super class" of normal net devices; split their locks off into a
 * separate class since they always nest.
 */
static struct lock_class_key nr_netdev_xmit_lock_key;
static struct lock_class_key nr_netdev_addr_lock_key;

static void nr_set_lockdep_one(struct net_device *dev,
                               struct netdev_queue *txq,
                               void *_unused)
{
        lockdep_set_class(&txq->_xmit_lock, &nr_netdev_xmit_lock_key);
}

static void nr_set_lockdep_key(struct net_device *dev)
{
        lockdep_set_class(&dev->addr_list_lock, &nr_netdev_addr_lock_key);
        netdev_for_each_tx_queue(dev, nr_set_lockdep_one, NULL);
}

/*
 *      Socket removal during an interrupt is now safe.
 */
static void nr_remove_socket(struct sock *sk)
{
        spin_lock_bh(&nr_list_lock);
        sk_del_node_init(sk);
        spin_unlock_bh(&nr_list_lock);
}

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

        spin_lock_bh(&nr_list_lock);
        sk_for_each(s, node, &nr_list)
                if (nr_sk(s)->device == dev)
                        nr_disconnect(s, ENETUNREACH);
        spin_unlock_bh(&nr_list_lock);
}

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

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

        if (event != NETDEV_DOWN)
                return NOTIFY_DONE;

        nr_kill_by_device(dev);
        nr_rt_device_down(dev);

        return NOTIFY_DONE;
}

/*
 *      Add a socket to the bound sockets list.
 */
static void nr_insert_socket(struct sock *sk)
{
        spin_lock_bh(&nr_list_lock);
        sk_add_node(sk, &nr_list);
        spin_unlock_bh(&nr_list_lock);
}

/*
 *      Find a socket that wants to accept the Connect Request we just
 *      received.
 */
static struct sock *nr_find_listener(ax25_address *addr)
{
        struct sock *s;
        struct hlist_node *node;

        spin_lock_bh(&nr_list_lock);
        sk_for_each(s, node, &nr_list)
                if (!ax25cmp(&nr_sk(s)->source_addr, addr) &&
                    s->sk_state == TCP_LISTEN) {
                        bh_lock_sock(s);
                        goto found;
                }
        s = NULL;
found:
        spin_unlock_bh(&nr_list_lock);
        return s;
}

/*
 *      Find a connected NET/ROM socket given my circuit IDs.
 */
static struct sock *nr_find_socket(unsigned char index, unsigned char id)
{
        struct sock *s;
        struct hlist_node *node;

        spin_lock_bh(&nr_list_lock);
        sk_for_each(s, node, &nr_list) {
                struct nr_sock *nr = nr_sk(s);

                if (nr->my_index == index && nr->my_id == id) {
                        bh_lock_sock(s);
                        goto found;
                }
        }
        s = NULL;
found:
        spin_unlock_bh(&nr_list_lock);
        return s;
}

/*
 *      Find a connected NET/ROM socket given their circuit IDs.
 */
static struct sock *nr_find_peer(unsigned char index, unsigned char id,
        ax25_address *dest)
{
        struct sock *s;
        struct hlist_node *node;

        spin_lock_bh(&nr_list_lock);
        sk_for_each(s, node, &nr_list) {
                struct nr_sock *nr = nr_sk(s);

                if (nr->your_index == index && nr->your_id == id &&
                    !ax25cmp(&nr->dest_addr, dest)) {
                        bh_lock_sock(s);
                        goto found;
                }
        }
        s = NULL;
found:
        spin_unlock_bh(&nr_list_lock);
        return s;
}

/*
 *      Find next free circuit ID.
 */
static unsigned short nr_find_next_circuit(void)
{
        unsigned short id = circuit;
        unsigned char i, j;
        struct sock *sk;

        for (;;) {
                i = id / 256;
                j = id % 256;

                if (i != 0 && j != 0) {
                        if ((sk=nr_find_socket(i, j)) == NULL)
                                break;
                        bh_unlock_sock(sk);
                }

                id++;
        }

        return id;
}

/*
 *      Deferred destroy.
 */
void nr_destroy_socket(struct sock *);

/*
 *      Handler for deferred kills.
 */
static void nr_destroy_timer(unsigned long data)
{
        struct sock *sk=(struct sock *)data;
        bh_lock_sock(sk);
        sock_hold(sk);
        nr_destroy_socket(sk);
        bh_unlock_sock(sk);
        sock_put(sk);
}

/*
 *      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.
 */
void nr_destroy_socket(struct sock *sk)
{
        struct sk_buff *skb;

        nr_remove_socket(sk);

        nr_stop_heartbeat(sk);
        nr_stop_t1timer(sk);
        nr_stop_t2timer(sk);
        nr_stop_t4timer(sk);
        nr_stop_idletimer(sk);

        nr_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 */
                        sock_set_flag(skb->sk, SOCK_DEAD);
                        nr_start_heartbeat(skb->sk);
                        nr_sk(skb->sk)->state = NR_STATE_0;
                }

                kfree_skb(skb);
        }

        if (atomic_read(&sk->sk_wmem_alloc) ||
            atomic_read(&sk->sk_rmem_alloc)) {
                /* Defer: outstanding buffers */
                sk->sk_timer.function = nr_destroy_timer;
                sk->sk_timer.expires  = jiffies + 2 * HZ;
                add_timer(&sk->sk_timer);
        } else
                sock_put(sk);
}

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

static int nr_setsockopt(struct socket *sock, int level, int optname,
        char __user *optval, int optlen)
{
        struct sock *sk = sock->sk;
        struct nr_sock *nr = nr_sk(sk);
        int opt;

        if (level != SOL_NETROM)
                return -ENOPROTOOPT;

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

        if (get_user(opt, (int __user *)optval))
                return -EFAULT;

        switch (optname) {
        case NETROM_T1:
                if (opt < 1)
                        return -EINVAL;
                nr->t1 = opt * HZ;
                return 0;

        case NETROM_T2:
                if (opt < 1)
                        return -EINVAL;
                nr->t2 = opt * HZ;
                return 0;

        case NETROM_N2:
                if (opt < 1 || opt > 31)
                        return -EINVAL;
                nr->n2 = opt;
                return 0;

        case NETROM_T4:
                if (opt < 1)
                        return -EINVAL;
                nr->t4 = opt * HZ;
                return 0;

        case NETROM_IDLE:
                if (opt < 0)
                        return -EINVAL;
                nr->idle = opt * 60 * HZ;
                return 0;

        default:
                return -ENOPROTOOPT;
        }
}

static int nr_getsockopt(struct socket *sock, int level, int optname,
        char __user *optval, int __user *optlen)
{
        struct sock *sk = sock->sk;
        struct nr_sock *nr = nr_sk(sk);
        int val = 0;
        int len;

        if (level != SOL_NETROM)
                return -ENOPROTOOPT;

        if (get_user(len, optlen))
                return -EFAULT;

        if (len < 0)
                return -EINVAL;

        switch (optname) {
        case NETROM_T1:
                val = nr->t1 / HZ;
                break;

        case NETROM_T2:
                val = nr->t2 / HZ;
                break;

        case NETROM_N2:
                val = nr->n2;
                break;

        case NETROM_T4:
                val = nr->t4 / HZ;
                break;

        case NETROM_IDLE:
                val = nr->idle / (60 * HZ);
                break;

        default:
                return -ENOPROTOOPT;
        }

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

        if (put_user(len, optlen))
                return -EFAULT;

        return copy_to_user(optval, &val, len) ? -EFAULT : 0;
}

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

        lock_sock(sk);
        if (sk->sk_state != TCP_LISTEN) {
                memset(&nr_sk(sk)->user_addr, 0, AX25_ADDR_LEN);
                sk->sk_max_ack_backlog = backlog;
                sk->sk_state           = TCP_LISTEN;
                release_sock(sk);
                return 0;
        }
        release_sock(sk);

        return -EOPNOTSUPP;
}

static struct proto nr_proto = {
        .name     = "NETROM",
        .owner    = THIS_MODULE,
        .obj_size = sizeof(struct nr_sock),
};

static int nr_create(struct net *net, struct socket *sock, int protocol)
{
        struct sock *sk;
        struct nr_sock *nr;

        if (net != &init_net)
                return -EAFNOSUPPORT;

        if (sock->type != SOCK_SEQPACKET || protocol != 0)
                return -ESOCKTNOSUPPORT;

        sk = sk_alloc(net, PF_NETROM, GFP_ATOMIC, &nr_proto);
        if (sk  == NULL)
                return -ENOMEM;

        nr = nr_sk(sk);

        sock_init_data(sock, sk);

        sock->ops    = &nr_proto_ops;
        sk->sk_protocol = protocol;

        skb_queue_head_init(&nr->ack_queue);
        skb_queue_head_init(&nr->reseq_queue);
        skb_queue_head_init(&nr->frag_queue);

        nr_init_timers(sk);

        nr->t1     =
                msecs_to_jiffies(sysctl_netrom_transport_timeout);
        nr->t2     =
                msecs_to_jiffies(sysctl_netrom_transport_acknowledge_delay);
        nr->n2     =
                msecs_to_jiffies(sysctl_netrom_transport_maximum_tries);
        nr->t4     =
                msecs_to_jiffies(sysctl_netrom_transport_busy_delay);
        nr->idle   =
                msecs_to_jiffies(sysctl_netrom_transport_no_activity_timeout);
        nr->window = sysctl_netrom_transport_requested_window_size;

        nr->bpqext = 1;
        nr->state  = NR_STATE_0;

        return 0;
}

static struct sock *nr_make_new(struct sock *osk)
{
        struct sock *sk;
        struct nr_sock *nr, *onr;

        if (osk->sk_type != SOCK_SEQPACKET)
                return NULL;

        sk = sk_alloc(sock_net(osk), PF_NETROM, GFP_ATOMIC, osk->sk_prot);
        if (sk == NULL)
                return NULL;

        nr = nr_sk(sk);

        sock_init_data(NULL, 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;
        sock_copy_flags(sk, osk);

        skb_queue_head_init(&nr->ack_queue);
        skb_queue_head_init(&nr->reseq_queue);
        skb_queue_head_init(&nr->frag_queue);

        nr_init_timers(sk);

        onr = nr_sk(osk);

        nr->t1      = onr->t1;
        nr->t2      = onr->t2;
        nr->n2      = onr->n2;
        nr->t4      = onr->t4;
        nr->idle    = onr->idle;
        nr->window  = onr->window;

        nr->device  = onr->device;
        nr->bpqext  = onr->bpqext;

        return sk;
}

static int nr_release(struct socket *sock)
{
        struct sock *sk = sock->sk;
        struct nr_sock *nr;

        if (sk == NULL) return 0;

        sock_hold(sk);
        sock_orphan(sk);
        lock_sock(sk);
        nr = nr_sk(sk);

        switch (nr->state) {
        case NR_STATE_0:
        case NR_STATE_1:
        case NR_STATE_2:
                nr_disconnect(sk, 0);
                nr_destroy_socket(sk);
                break;

        case NR_STATE_3:
                nr_clear_queues(sk);
                nr->n2count = 0;
                nr_write_internal(sk, NR_DISCREQ);
                nr_start_t1timer(sk);
                nr_stop_t2timer(sk);
                nr_stop_t4timer(sk);
                nr_stop_idletimer(sk);
                nr->state    = NR_STATE_2;
                sk->sk_state    = TCP_CLOSE;
                sk->sk_shutdown |= SEND_SHUTDOWN;
                sk->sk_state_change(sk);
                sock_set_flag(sk, SOCK_DESTROY);
                break;

        default:
                break;
        }

        sock->sk   = NULL;
        release_sock(sk);
        sock_put(sk);

        return 0;
}

static int nr_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
        struct sock *sk = sock->sk;
        struct nr_sock *nr = nr_sk(sk);
        struct full_sockaddr_ax25 *addr = (struct full_sockaddr_ax25 *)uaddr;
        struct net_device *dev;
        ax25_uid_assoc *user;
        ax25_address *source;

        lock_sock(sk);
        if (!sock_flag(sk, SOCK_ZAPPED)) {
                release_sock(sk);
                return -EINVAL;
        }
        if (addr_len < sizeof(struct sockaddr_ax25) || addr_len > sizeof(struct full_sockaddr_ax25)) {
                release_sock(sk);
                return -EINVAL;
        }
        if (addr_len < (addr->fsa_ax25.sax25_ndigis * sizeof(ax25_address) + sizeof(struct sockaddr_ax25))) {
                release_sock(sk);
                return -EINVAL;
        }
        if (addr->fsa_ax25.sax25_family != AF_NETROM) {
                release_sock(sk);
                return -EINVAL;
        }
        if ((dev = nr_dev_get(&addr->fsa_ax25.sax25_call)) == NULL) {
                SOCK_DEBUG(sk, "NET/ROM: bind failed: invalid node callsign\n");
                release_sock(sk);
                return -EADDRNOTAVAIL;
        }

        /*
         * Only the super user can set an arbitrary user callsign.
         */
        if (addr->fsa_ax25.sax25_ndigis == 1) {
                if (!capable(CAP_NET_BIND_SERVICE)) {
                        dev_put(dev);
                        release_sock(sk);
                        return -EACCES;
                }
                nr->user_addr   = addr->fsa_digipeater[0];
                nr->source_addr = addr->fsa_ax25.sax25_call;
        } else {
                source = &addr->fsa_ax25.sax25_call;

                user = ax25_findbyuid(current->euid);
                if (user) {
                        nr->user_addr   = user->call;
                        ax25_uid_put(user);
                } else {
                        if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
                                release_sock(sk);
                                dev_put(dev);
                                return -EPERM;
                        }
                        nr->user_addr   = *source;
                }

                nr->source_addr = *source;
        }

        nr->device = dev;
        nr_insert_socket(sk);

        sock_reset_flag(sk, SOCK_ZAPPED);
        dev_put(dev);
        release_sock(sk);
        SOCK_DEBUG(sk, "NET/ROM: socket is bound\n");
        return 0;
}

static int nr_connect(struct socket *sock, struct sockaddr *uaddr,
        int addr_len, int flags)
{
        struct sock *sk = sock->sk;
        struct nr_sock *nr = nr_sk(sk);
        struct sockaddr_ax25 *addr = (struct sockaddr_ax25 *)uaddr;
        ax25_address *source = NULL;
        ax25_uid_assoc *user;
        struct net_device *dev;
        int err = 0;

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

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

        if (sk->sk_state == TCP_ESTABLISHED) {
                err = -EISCONN; /* No reconnect on a seqpacket socket */
                goto out_release;
        }

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

        if (addr_len != sizeof(struct sockaddr_ax25) && addr_len != sizeof(struct full_sockaddr_ax25)) {
                err = -EINVAL;
                goto out_release;
        }
        if (addr->sax25_family != AF_NETROM) {
                err = -EINVAL;
                goto out_release;
        }
        if (sock_flag(sk, SOCK_ZAPPED)) {       /* Must bind first - autobinding in this may or may not work */
                sock_reset_flag(sk, SOCK_ZAPPED);

                if ((dev = nr_dev_first()) == NULL) {
                        err = -ENETUNREACH;
                        goto out_release;
                }
                source = (ax25_address *)dev->dev_addr;

                user = ax25_findbyuid(current->euid);
                if (user) {
                        nr->user_addr   = user->call;
                        ax25_uid_put(user);
                } else {
                        if (ax25_uid_policy && !capable(CAP_NET_ADMIN)) {
                                dev_put(dev);
                                err = -EPERM;
                                goto out_release;
                        }
                        nr->user_addr   = *source;
                }

                nr->source_addr = *source;
                nr->device      = dev;

                dev_put(dev);
                nr_insert_socket(sk);           /* Finish the bind */
        }

        nr->dest_addr = addr->sax25_call;

        release_sock(sk);
        circuit = nr_find_next_circuit();
        lock_sock(sk);

        nr->my_index = circuit / 256;
        nr->my_id    = circuit % 256;

        circuit++;

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

        nr_establish_data_link(sk);

        nr->state = NR_STATE_1;

        nr_start_heartbeat(sk);

        /* Now the loop */
        if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK)) {
                err = -EINPROGRESS;
                goto out_release;
        }

        /*
         * A Connect Ack with Choke or timeout or failed routing will go to
         * closed.
         */
        if (sk->sk_state == TCP_SYN_SENT) {
                DEFINE_WAIT(wait);

                for (;;) {
                        prepare_to_wait(sk->sk_sleep, &wait,
                                        TASK_INTERRUPTIBLE);
                        if (sk->sk_state != TCP_SYN_SENT)
                                break;
                        if (!signal_pending(current)) {
                                release_sock(sk);
                                schedule();
                                lock_sock(sk);
                                continue;
                        }
                        err = -ERESTARTSYS;
                        break;
                }
                finish_wait(sk->sk_sleep, &wait);
                if (err)
                        goto out_release;
        }

        if (sk->sk_state != TCP_ESTABLISHED) {
                sock->state = SS_UNCONNECTED;
                err = sock_error(sk);   /* Always set at this point */
                goto out_release;
        }

        sock->state = SS_CONNECTED;

out_release:
        release_sock(sk);

        return err;
}

static int nr_accept(struct socket *sock, struct socket *newsock, int flags)
{
        struct sk_buff *skb;
        struct sock *newsk;
        DEFINE_WAIT(wait);
        struct sock *sk;
        int err = 0;

        if ((sk = sock->sk) == NULL)
                return -EINVAL;

        lock_sock(sk);
        if (sk->sk_type != SOCK_SEQPACKET) {
                err = -EOPNOTSUPP;
                goto out_release;
        }

        if (sk->sk_state != TCP_LISTEN) {
                err = -EINVAL;
                goto out_release;
        }

        /*
         *      The write queue this time is holding sockets ready to use
         *      hooked into the SABM we saved
         */
        for (;;) {
                prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
                skb = skb_dequeue(&sk->sk_receive_queue);
                if (skb)
                        break;

                if (flags & O_NONBLOCK) {
                        err = -EWOULDBLOCK;
                        break;
                }
                if (!signal_pending(current)) {
                        release_sock(sk);
                        schedule();
                        lock_sock(sk);
                        continue;
                }
                err = -ERESTARTSYS;
                break;
        }
        finish_wait(sk->sk_sleep, &wait);
        if (err)
                goto out_release;

        newsk = skb->sk;
        sock_graft(newsk, newsock);

        /* Now attach up the new socket */
        kfree_skb(skb);
        sk_acceptq_removed(sk);

out_release:
        release_sock(sk);

        return err;
}

static int nr_getname(struct socket *sock, struct sockaddr *uaddr,
        int *uaddr_len, int peer)
{
        struct full_sockaddr_ax25 *sax = (struct full_sockaddr_ax25 *)uaddr;
        struct sock *sk = sock->sk;
        struct nr_sock *nr = nr_sk(sk);

        lock_sock(sk);
        if (peer != 0) {
                if (sk->sk_state != TCP_ESTABLISHED) {
                        release_sock(sk);
                        return -ENOTCONN;
                }
                sax->fsa_ax25.sax25_family = AF_NETROM;
                sax->fsa_ax25.sax25_ndigis = 1;
                sax->fsa_ax25.sax25_call   = nr->user_addr;
                sax->fsa_digipeater[0]     = nr->dest_addr;
                *uaddr_len = sizeof(struct full_sockaddr_ax25);
        } else {
                sax->fsa_ax25.sax25_family = AF_NETROM;
                sax->fsa_ax25.sax25_ndigis = 0;
                sax->fsa_ax25.sax25_call   = nr->source_addr;
                *uaddr_len = sizeof(struct sockaddr_ax25);
        }
        release_sock(sk);

        return 0;
}

int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
{
        struct sock *sk;
        struct sock *make;
        struct nr_sock *nr_make;
        ax25_address *src, *dest, *user;
        unsigned short circuit_index, circuit_id;
        unsigned short peer_circuit_index, peer_circuit_id;
        unsigned short frametype, flags, window, timeout;
        int ret;

        skb->sk = NULL;         /* Initially we don't know who it's for */

        /*
         *      skb->data points to the netrom frame start
         */

        src  = (ax25_address *)(skb->data + 0);
        dest = (ax25_address *)(skb->data + 7);

        circuit_index      = skb->data[15];
        circuit_id         = skb->data[16];
        peer_circuit_index = skb->data[17];
        peer_circuit_id    = skb->data[18];
        frametype          = skb->data[19] & 0x0F;
        flags              = skb->data[19] & 0xF0;

        /*
         * Check for an incoming IP over NET/ROM frame.
         */
        if (frametype == NR_PROTOEXT &&
            circuit_index == NR_PROTO_IP && circuit_id == NR_PROTO_IP) {
                skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
                skb_reset_transport_header(skb);

                return nr_rx_ip(skb, dev);
        }

        /*
         * Find an existing socket connection, based on circuit ID, if it's
         * a Connect Request base it on their circuit ID.
         *
         * Circuit ID 0/0 is not valid but it could still be a "reset" for a
         * circuit that no longer exists at the other end ...
         */

        sk = NULL;

        if (circuit_index == 0 && circuit_id == 0) {
                if (frametype == NR_CONNACK && flags == NR_CHOKE_FLAG)
                        sk = nr_find_peer(peer_circuit_index, peer_circuit_id, src);
        } else {
                if (frametype == NR_CONNREQ)
                        sk = nr_find_peer(circuit_index, circuit_id, src);
                else
                        sk = nr_find_socket(circuit_index, circuit_id);
        }

        if (sk != NULL) {
                skb_reset_transport_header(skb);

                if (frametype == NR_CONNACK && skb->len == 22)
                        nr_sk(sk)->bpqext = 1;
                else
                        nr_sk(sk)->bpqext = 0;

                ret = nr_process_rx_frame(sk, skb);
                bh_unlock_sock(sk);
                return ret;
        }

        /*
         * Now it should be a CONNREQ.
         */
        if (frametype != NR_CONNREQ) {
                /*
                 * Here it would be nice to be able to send a reset but
                 * NET/ROM doesn't have one.  We've tried to extend the protocol
                 * by sending NR_CONNACK | NR_CHOKE_FLAGS replies but that
                 * apparently kills BPQ boxes... :-(
                 * So now we try to follow the established behaviour of
                 * G8PZT's Xrouter which is sending packets with command type 7
                 * as an extension of the protocol.
                 */
                if (sysctl_netrom_reset_circuit &&
                    (frametype != NR_RESET || flags != 0))
                        nr_transmit_reset(skb, 1);

                return 0;
        }

        sk = nr_find_listener(dest);

        user = (ax25_address *)(skb->data + 21);

        if (sk == NULL || sk_acceptq_is_full(sk) ||
            (make = nr_make_new(sk)) == NULL) {
                nr_transmit_refusal(skb, 0);
                if (sk)
                        bh_unlock_sock(sk);
                return 0;
        }

        window = skb->data[20];

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

        /* Fill in his circuit details */
        nr_make = nr_sk(make);
        nr_make->source_addr = *dest;
        nr_make->dest_addr   = *src;
        nr_make->user_addr   = *user;

        nr_make->your_index  = circuit_index;
        nr_make->your_id     = circuit_id;

        bh_unlock_sock(sk);
        circuit = nr_find_next_circuit();
        bh_lock_sock(sk);

        nr_make->my_index    = circuit / 256;
        nr_make->my_id       = circuit % 256;

        circuit++;

        /* Window negotiation */
        if (window < nr_make->window)
                nr_make->window = window;

        /* L4 timeout negotiation */
        if (skb->len == 37) {
                timeout = skb->data[36] * 256 + skb->data[35];
                if (timeout * HZ < nr_make->t1)
                        nr_make->t1 = timeout * HZ;
                nr_make->bpqext = 1;
        } else {
                nr_make->bpqext = 0;
        }

        nr_write_internal(make, NR_CONNACK);

        nr_make->condition = 0x00;
        nr_make->vs        = 0;
        nr_make->va        = 0;
        nr_make->vr        = 0;
        nr_make->vl        = 0;
        nr_make->state     = NR_STATE_3;
        sk_acceptq_added(sk);
        skb_queue_head(&sk->sk_receive_queue, skb);

        if (!sock_flag(sk, SOCK_DEAD))
                sk->sk_data_ready(sk, skb->len);

        bh_unlock_sock(sk);

        nr_insert_socket(make);

        nr_start_heartbeat(make);
        nr_start_idletimer(make);

        return 1;
}

static int nr_sendmsg(struct kiocb *iocb, struct socket *sock,
                      struct msghdr *msg, size_t len)
{
        struct sock *sk = sock->sk;
        struct nr_sock *nr = nr_sk(sk);
        struct sockaddr_ax25 *usax = (struct sockaddr_ax25 *)msg->msg_name;
        int err;
        struct sockaddr_ax25 sax;
        struct sk_buff *skb;
        unsigned char *asmptr;
        int size;

        if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_CMSG_COMPAT))
                return -EINVAL;

        lock_sock(sk);
        if (sock_flag(sk, SOCK_ZAPPED)) {
                err = -EADDRNOTAVAIL;
                goto out;
        }

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

        if (nr->device == NULL) {
                err = -ENETUNREACH;
                goto out;
        }

        if (usax) {
                if (msg->msg_namelen < sizeof(sax)) {
                        err = -EINVAL;
                        goto out;
                }
                sax = *usax;
                if (ax25cmp(&nr->dest_addr, &sax.sax25_call) != 0) {
                        err = -EISCONN;
                        goto out;
                }
                if (sax.sax25_family != AF_NETROM) {
                        err = -EINVAL;
                        goto out;
                }
        } else {
                if (sk->sk_state != TCP_ESTABLISHED) {
                        err = -ENOTCONN;
                        goto out;
                }
                sax.sax25_family = AF_NETROM;
                sax.sax25_call   = nr->dest_addr;
        }

        SOCK_DEBUG(sk, "NET/ROM: sendto: Addresses built.\n");

        /* Build a packet */
        SOCK_DEBUG(sk, "NET/ROM: sendto: building packet.\n");
        size = len + NR_NETWORK_LEN + NR_TRANSPORT_LEN;

        if ((skb = sock_alloc_send_skb(sk, size, msg->msg_flags & MSG_DONTWAIT, &err)) == NULL)
                goto out;

        skb_reserve(skb, size - len);
        skb_reset_transport_header(skb);

        /*
         *      Push down the NET/ROM header
         */

        asmptr = skb_push(skb, NR_TRANSPORT_LEN);
        SOCK_DEBUG(sk, "Building NET/ROM Header.\n");

        /* Build a NET/ROM Transport header */

        *asmptr++ = nr->your_index;
        *asmptr++ = nr->your_id;
        *asmptr++ = 0;          /* To be filled in later */
        *asmptr++ = 0;          /*      Ditto            */
        *asmptr++ = NR_INFO;
        SOCK_DEBUG(sk, "Built header.\n");

        /*
         *      Put the data on the end
         */
        skb_put(skb, len);

        SOCK_DEBUG(sk, "NET/ROM: Appending user data\n");

        /* User data follows immediately after the NET/ROM transport header */
        if (memcpy_fromiovec(skb_transport_header(skb), msg->msg_iov, len)) {
                kfree_skb(skb);
                err = -EFAULT;
                goto out;
        }

        SOCK_DEBUG(sk, "NET/ROM: Transmitting buffer\n");

        if (sk->sk_state != TCP_ESTABLISHED) {
                kfree_skb(skb);
                err = -ENOTCONN;
                goto out;
        }

        nr_output(sk, skb);     /* Shove it onto the queue */

        err = len;
out:
        release_sock(sk);
        return err;
}

static int nr_recvmsg(struct kiocb *iocb, struct socket *sock,
                      struct msghdr *msg, size_t size, int flags)
{
        struct sock *sk = sock->sk;
        struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)msg->msg_name;
        size_t copied;
        struct sk_buff *skb;
        int er;

        /*
         * This works for seqpacket too. The receiver has ordered the queue for
         * us! We do one quick check first though
         */

        lock_sock(sk);
        if (sk->sk_state != TCP_ESTABLISHED) {
                release_sock(sk);
                return -ENOTCONN;
        }

        /* Now we can treat all alike */
        if ((skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &er)) == NULL) {
                release_sock(sk);
                return er;
        }

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

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

        skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

        if (sax != NULL) {
                sax->sax25_family = AF_NETROM;
                skb_copy_from_linear_data_offset(skb, 7, sax->sax25_call.ax25_call,
                              AX25_ADDR_LEN);
        }

        msg->msg_namelen = sizeof(*sax);

        skb_free_datagram(sk, skb);

        release_sock(sk);
        return copied;
}


static int nr_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        struct sock *sk = sock->sk;
        void __user *argp = (void __user *)arg;
        int ret;

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

                lock_sock(sk);
                amount = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
                if (amount < 0)
                        amount = 0;
                release_sock(sk);
                return put_user(amount, (int __user *)argp);
        }

        case TIOCINQ: {
                struct sk_buff *skb;
                long amount = 0L;

                lock_sock(sk);
                /* These two are safe on a single CPU system as only user tasks fiddle here */
                if ((skb = skb_peek(&sk->sk_receive_queue)) != NULL)
                        amount = skb->len;
                release_sock(sk);
                return put_user(amount, (int __user *)argp);
        }

        case SIOCGSTAMP:
                lock_sock(sk);
                ret = sock_get_timestamp(sk, argp);
                release_sock(sk);
                return ret;

        case SIOCGSTAMPNS:
                lock_sock(sk);
                ret = sock_get_timestampns(sk, argp);
                release_sock(sk);
                return ret;

        case SIOCGIFADDR:
        case SIOCSIFADDR:
        case SIOCGIFDSTADDR:
        case SIOCSIFDSTADDR:
        case SIOCGIFBRDADDR:
        case SIOCSIFBRDADDR:
        case SIOCGIFNETMASK:
        case SIOCSIFNETMASK:
        case SIOCGIFMETRIC:
        case SIOCSIFMETRIC:
                return -EINVAL;

        case SIOCADDRT:
        case SIOCDELRT:
        case SIOCNRDECOBS:
                if (!capable(CAP_NET_ADMIN)) return -EPERM;
                return nr_rt_ioctl(cmd, argp);

        default:
                return -ENOIOCTLCMD;
        }

        return 0;
}

#ifdef CONFIG_PROC_FS

static void *nr_info_start(struct seq_file *seq, loff_t *pos)
{
        struct sock *s;
        struct hlist_node *node;
        int i = 1;

        spin_lock_bh(&nr_list_lock);
        if (*pos == 0)
                return SEQ_START_TOKEN;

        sk_for_each(s, node, &nr_list) {
                if (i == *pos)
                        return s;
                ++i;
        }
        return NULL;
}

static void *nr_info_next(struct seq_file *seq, void *v, loff_t *pos)
{
        ++*pos;

        return (v == SEQ_START_TOKEN) ? sk_head(&nr_list)
                : sk_next((struct sock *)v);
}

static void nr_info_stop(struct seq_file *seq, void *v)
{
        spin_unlock_bh(&nr_list_lock);
}

static int nr_info_show(struct seq_file *seq, void *v)
{
        struct sock *s = v;
        struct net_device *dev;
        struct nr_sock *nr;
        const char *devname;
        char buf[11];

        if (v == SEQ_START_TOKEN)
                seq_puts(seq,
"user_addr dest_node src_node  dev    my  your  st  vs  vr  va    t1     t2     t4      idle   n2  wnd Snd-Q Rcv-Q inode\n");

        else {

                bh_lock_sock(s);
                nr = nr_sk(s);

                if ((dev = nr->device) == NULL)
                        devname = "???";
                else
                        devname = dev->name;

                seq_printf(seq, "%-9s ", ax2asc(buf, &nr->user_addr));
                seq_printf(seq, "%-9s ", ax2asc(buf, &nr->dest_addr));
                seq_printf(seq,
"%-9s %-3s  %02X/%02X %02X/%02X %2d %3d %3d %3d %3lu/%03lu %2lu/%02lu %3lu/%03lu %3lu/%03lu %2d/%02d %3d %5d %5d %ld\n",
                        ax2asc(buf, &nr->source_addr),
                        devname,
                        nr->my_index,
                        nr->my_id,
                        nr->your_index,
                        nr->your_id,
                        nr->state,
                        nr->vs,
                        nr->vr,
                        nr->va,
                        ax25_display_timer(&nr->t1timer) / HZ,
                        nr->t1 / HZ,
                        ax25_display_timer(&nr->t2timer) / HZ,
                        nr->t2 / HZ,
                        ax25_display_timer(&nr->t4timer) / HZ,
                        nr->t4 / HZ,
                        ax25_display_timer(&nr->idletimer) / (60 * HZ),
                        nr->idle / (60 * HZ),
                        nr->n2count,
                        nr->n2,
                        nr->window,
                        atomic_read(&s->sk_wmem_alloc),
                        atomic_read(&s->sk_rmem_alloc),
                        s->sk_socket ? SOCK_INODE(s->sk_socket)->i_ino : 0L);

                bh_unlock_sock(s);
        }
        return 0;
}

static const struct seq_operations nr_info_seqops = {
        .start = nr_info_start,
        .next = nr_info_next,
        .stop = nr_info_stop,
        .show = nr_info_show,
};

static int nr_info_open(struct inode *inode, struct file *file)
{
        return seq_open(file, &nr_info_seqops);
}

static const struct file_operations nr_info_fops = {
        .owner = THIS_MODULE,
        .open = nr_info_open,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = seq_release,
};
#endif  /* CONFIG_PROC_FS */

static struct net_proto_family nr_family_ops = {
        .family         =       PF_NETROM,
        .create         =       nr_create,
        .owner          =       THIS_MODULE,
};

static const struct proto_ops nr_proto_ops = {
        .family         =       PF_NETROM,
        .owner          =       THIS_MODULE,
        .release        =       nr_release,
        .bind           =       nr_bind,
        .connect        =       nr_connect,
        .socketpair     =       sock_no_socketpair,
        .accept         =       nr_accept,
        .getname        =       nr_getname,
        .poll           =       datagram_poll,
        .ioctl          =       nr_ioctl,
        .listen         =       nr_listen,
        .shutdown       =       sock_no_shutdown,
        .setsockopt     =       nr_setsockopt,
        .getsockopt     =       nr_getsockopt,
        .sendmsg        =       nr_sendmsg,
        .recvmsg        =       nr_recvmsg,
        .mmap           =       sock_no_mmap,
        .sendpage       =       sock_no_sendpage,
};

static struct notifier_block nr_dev_notifier = {
        .notifier_call  =       nr_device_event,
};

static struct net_device **dev_nr;

static struct ax25_protocol nr_pid = {
        .pid    = AX25_P_NETROM,
        .func   = nr_route_frame
};

static struct ax25_linkfail nr_linkfail_notifier = {
        .func   = nr_link_failed,
};

static int __init nr_proto_init(void)
{
        int i;
        int rc = proto_register(&nr_proto, 0);

        if (rc != 0)
                goto out;

        if (nr_ndevs > 0x7fffffff/sizeof(struct net_device *)) {
                printk(KERN_ERR "NET/ROM: nr_proto_init - nr_ndevs parameter to large\n");
                return -1;
        }

        dev_nr = kzalloc(nr_ndevs * sizeof(struct net_device *), GFP_KERNEL);
        if (dev_nr == NULL) {
                printk(KERN_ERR "NET/ROM: nr_proto_init - unable to allocate device array\n");
                return -1;
        }

        for (i = 0; i < nr_ndevs; i++) {
                char name[IFNAMSIZ];
                struct net_device *dev;

                sprintf(name, "nr%d", i);
                dev = alloc_netdev(sizeof(struct nr_private), name, nr_setup);
                if (!dev) {
                        printk(KERN_ERR "NET/ROM: nr_proto_init - unable to allocate device structure\n");
                        goto fail;
                }

                dev->base_addr = i;
                if (register_netdev(dev)) {
                        printk(KERN_ERR "NET/ROM: nr_proto_init - unable to register network device\n");
                        free_netdev(dev);
                        goto fail;
                }
                nr_set_lockdep_key(dev);
                dev_nr[i] = dev;
        }

        if (sock_register(&nr_family_ops)) {
                printk(KERN_ERR "NET/ROM: nr_proto_init - unable to register socket family\n");
                goto fail;
        }

        register_netdevice_notifier(&nr_dev_notifier);

        ax25_register_pid(&nr_pid);
        ax25_linkfail_register(&nr_linkfail_notifier);

#ifdef CONFIG_SYSCTL
        nr_register_sysctl();
#endif

        nr_loopback_init();

        proc_net_fops_create(&init_net, "nr", S_IRUGO, &nr_info_fops);
        proc_net_fops_create(&init_net, "nr_neigh", S_IRUGO, &nr_neigh_fops);
        proc_net_fops_create(&init_net, "nr_nodes", S_IRUGO, &nr_nodes_fops);
out:
        return rc;
fail:
        while (--i >= 0) {
                unregister_netdev(dev_nr[i]);
                free_netdev(dev_nr[i]);
        }
        kfree(dev_nr);
        proto_unregister(&nr_proto);
        rc = -1;
        goto out;
}

module_init(nr_proto_init);

module_param(nr_ndevs, int, 0);
MODULE_PARM_DESC(nr_ndevs, "number of NET/ROM devices");

MODULE_AUTHOR("Jonathan Naylor G4KLX <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The amateur radio NET/ROM network and transport layer protocol");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_NETROM);

static void __exit nr_exit(void)
{
        int i;

        proc_net_remove(&init_net, "nr");
        proc_net_remove(&init_net, "nr_neigh");
        proc_net_remove(&init_net, "nr_nodes");
        nr_loopback_clear();

        nr_rt_free();

#ifdef CONFIG_SYSCTL
        nr_unregister_sysctl();
#endif

        ax25_linkfail_release(&nr_linkfail_notifier);
        ax25_protocol_release(AX25_P_NETROM);

        unregister_netdevice_notifier(&nr_dev_notifier);

        sock_unregister(PF_NETROM);

        for (i = 0; i < nr_ndevs; i++) {
                struct net_device *dev = dev_nr[i];
                if (dev) {
                        unregister_netdev(dev);
                        free_netdev(dev);
                }
        }

        kfree(dev_nr);
        proto_unregister(&nr_proto);
}
module_exit(nr_exit);

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