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af_netrom.c
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af_netrom.c
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/*
* 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/slab.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 <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;
spin_lock_bh(&nr_list_lock);
sk_for_each(s, &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 = netdev_notifier_info_to_dev(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;
spin_lock_bh(&nr_list_lock);
sk_for_each(s, &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;
spin_lock_bh(&nr_list_lock);
sk_for_each(s, &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;
spin_lock_bh(&nr_list_lock);
sk_for_each(s, &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 (sk_has_allocations(sk)) {
/* 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, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct nr_sock *nr = nr_sk(sk);
unsigned long opt;
if (level != SOL_NETROM)
return -ENOPROTOOPT;
if (optlen < sizeof(unsigned int))
return -EINVAL;
if (get_user(opt, (unsigned int __user *)optval))
return -EFAULT;
switch (optname) {
case NETROM_T1:
if (opt < 1 || opt > ULONG_MAX / HZ)
return -EINVAL;
nr->t1 = opt * HZ;
return 0;
case NETROM_T2:
if (opt < 1 || opt > ULONG_MAX / HZ)
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 || opt > ULONG_MAX / HZ)
return -EINVAL;
nr->t4 = opt * HZ;
return 0;
case NETROM_IDLE:
if (opt > ULONG_MAX / (60 * HZ))
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,
int kern)
{
struct sock *sk;
struct nr_sock *nr;
if (!net_eq(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) {
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 -EPERM;
}
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);
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_sleep(sk), &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_sleep(sk), &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_sleep(sk), &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_sleep(sk), &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);
memset(&sax->fsa_ax25, 0, sizeof(struct sockaddr_ax25));
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;
memset(sax->fsa_digipeater, 0, sizeof(sax->fsa_digipeater));
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;
}