af_netrom.c

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/*
 *	NET/ROM release 007
 *
 *	This code REQUIRES 2.1.15 or higher/ NET3.038
 *
 *	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
 *	NET/ROM 001	Jonathan(G4KLX)	Cloned from the AX25 code.
 *	NET/ROM 002	Darryl(G7LED)	Fixes and address enhancement.
 *			Jonathan(G4KLX)	Complete bind re-think.
 *			Alan(GW4PTS)	Trivial tweaks into new format.
 *	NET/ROM	003	Jonathan(G4KLX)	Added G8BPQ extensions.
 *					Added NET/ROM routing ioctl.
 *			Darryl(G7LED)	Fix autobinding (on connect).
 *					Fixed nr_release(), set TCP_CLOSE, wakeup app
 *					context, THEN make the sock dead.
 *					Circuit ID check before allocating it on
 *					a connection.
 *			Alan(GW4PTS)	sendmsg/recvmsg only. Fixed connect clear bug
 *					inherited from AX.25
 *	NET/ROM 004	Jonathan(G4KLX)	Converted to module.
 *	NET/ROM 005	Jonathan(G4KLX) Linux 2.1
 *			Alan(GW4PTS)	Started POSIXisms
 *	NET/ROM 006	Alan(GW4PTS)	Brought in line with the ANK changes
 *			Jonathan(G4KLX)	Removed hdrincl.
 *	NET/ROM 007	Jonathan(G4KLX)	New timer architecture.
 *					Impmented Idle timer.
 *			Arnaldo C. Melo s/suser/capable/, micro cleanups
 */

#include <linux/config.h>
#include <linux/module.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/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 <net/ip.h>
#include <net/arp.h>
#include <linux/init.h>

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;

static unsigned short circuit = 0x101;

static struct sock *volatile nr_list;

static struct proto_ops nr_proto_ops;

static void nr_free_sock(struct sock *sk)
{
	sk_free(sk);

	MOD_DEC_USE_COUNT;
}

static struct sock *nr_alloc_sock(void)
{
	struct sock *sk;
	nr_cb *nr;

	if ((sk = sk_alloc(PF_NETROM, GFP_ATOMIC, 1)) == NULL)
		return NULL;

	if ((nr = kmalloc(sizeof(*nr), GFP_ATOMIC)) == NULL) {
		sk_free(sk);
		return NULL;
	}

	MOD_INC_USE_COUNT;

	memset(nr, 0x00, sizeof(*nr));

	sk->protinfo.nr = nr;
	nr->sk = sk;

	return sk;
}

/*
 *	Socket removal during an interrupt is now safe.
 */
static void nr_remove_socket(struct sock *sk)
{
	struct sock *s;
	unsigned long flags;

	save_flags(flags); cli();

	if ((s = nr_list) == sk) {
		nr_list = s->next;
		restore_flags(flags);
		return;
	}

	while (s != NULL && s->next != NULL) {
		if (s->next == sk) {
			s->next = sk->next;
			restore_flags(flags);
			return;
		}

		s = s->next;
	}

	restore_flags(flags);
}

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

	for (s = nr_list; s != NULL; s = s->next) {
		if (s->protinfo.nr->device == dev)
			nr_disconnect(s, ENETUNREACH);
	}
}

/*
 *	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 (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)
{
	unsigned long flags;

	save_flags(flags); cli();

	sk->next = nr_list;
	nr_list  = sk;

	restore_flags(flags);
}

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

	save_flags(flags);
	cli();

	for (s = nr_list; s != NULL; s = s->next) {
		if (ax25cmp(&s->protinfo.nr->source_addr, addr) == 0 && s->state == TCP_LISTEN) {
			restore_flags(flags);
			return s;
		}
	}

	restore_flags(flags);
	return NULL;
}

/*
 *	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;
	unsigned long flags;

	save_flags(flags);
	cli();

	for (s = nr_list; s != NULL; s = s->next) {
		if (s->protinfo.nr->my_index == index && s->protinfo.nr->my_id == id) {
			restore_flags(flags);
			return s;
		}
	}

	restore_flags(flags);

	return NULL;
}

/*
 *	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;
	unsigned long flags;

	save_flags(flags);
	cli();

	for (s = nr_list; s != NULL; s = s->next) {
		if (s->protinfo.nr->your_index == index && s->protinfo.nr->your_id == id && ax25cmp(&s->protinfo.nr->dest_addr, dest) == 0) {
			restore_flags(flags);
			return s;
		}
	}

	restore_flags(flags);

	return NULL;
}

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

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

		if (i != 0 && j != 0)
			if (nr_find_socket(i, j) == NULL)
				break;

		id++;
	}

	return id;
}

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

/*
 *	Handler for deferred kills.
 */
static void nr_destroy_timer(unsigned long data)
{
	nr_destroy_socket((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.
 */
void nr_destroy_socket(struct sock *sk)	/* Not static as it's used by the timer */
{
	struct sk_buff *skb;
	unsigned long flags;

	save_flags(flags); cli();

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

	nr_remove_socket(sk);
	nr_clear_queues(sk);		/* Flush the queues */

	while ((skb = skb_dequeue(&sk->receive_queue)) != NULL) {
		if (skb->sk != sk) {			/* A pending connection */
			skb->sk->dead = 1;	/* Queue the unaccepted socket for death */
			nr_start_heartbeat(skb->sk);
			skb->sk->protinfo.nr->state = NR_STATE_0;
		}

		kfree_skb(skb);
	}

	if (atomic_read(&sk->wmem_alloc) != 0 || atomic_read(&sk->rmem_alloc) != 0) {
		/* Defer: outstanding buffers */
		init_timer(&sk->timer);
		sk->timer.expires  = jiffies + 10 * HZ;
		sk->timer.function = nr_destroy_timer;
		sk->timer.data     = (unsigned long)sk;
		add_timer(&sk->timer);
	} else {
		nr_free_sock(sk);
	}

	restore_flags(flags);
}

/*
 *	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 *optval, int optlen)
{
	struct sock *sk = sock->sk;
	int opt;

	if (level != SOL_NETROM)
		return -ENOPROTOOPT;

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

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

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

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

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

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

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

		default:
			return -ENOPROTOOPT;
	}
}

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

	if (level != SOL_NETROM)
		return -ENOPROTOOPT;
	
	if (get_user(len, optlen))
		return -EFAULT;

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

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

		case NETROM_N2:
			val = sk->protinfo.nr->n2;
			break;

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

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

		default:
			return -ENOPROTOOPT;
	}

	len = min(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;

	if (sk->state != TCP_LISTEN) {
		memset(&sk->protinfo.nr->user_addr, '\0', AX25_ADDR_LEN);
		sk->max_ack_backlog = backlog;
		sk->state           = TCP_LISTEN;
		return 0;
	}

	return -EOPNOTSUPP;
}

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

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

	if ((sk = nr_alloc_sock()) == NULL)
		return -ENOMEM;

	nr = sk->protinfo.nr;

	sock_init_data(sock, sk);

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

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

	init_timer(&nr->t1timer);
	init_timer(&nr->t2timer);
	init_timer(&nr->t4timer);
	init_timer(&nr->idletimer);

	nr->t1     = sysctl_netrom_transport_timeout;
	nr->t2     = sysctl_netrom_transport_acknowledge_delay;
	nr->n2     = sysctl_netrom_transport_maximum_tries;
	nr->t4     = sysctl_netrom_transport_busy_delay;
	nr->idle   = 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;
	nr_cb *nr;

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

	if ((sk = nr_alloc_sock()) == NULL)
		return NULL;

	nr = sk->protinfo.nr;

	sock_init_data(NULL, sk);

	sk->type     = osk->type;
	sk->socket   = osk->socket;
	sk->priority = osk->priority;
	sk->protocol = osk->protocol;
	sk->rcvbuf   = osk->rcvbuf;
	sk->sndbuf   = osk->sndbuf;
	sk->debug    = osk->debug;
	sk->state    = TCP_ESTABLISHED;
	sk->sleep    = osk->sleep;
	sk->zapped   = osk->zapped;

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

	init_timer(&nr->t1timer);
	init_timer(&nr->t2timer);
	init_timer(&nr->t4timer);
	init_timer(&nr->idletimer);

	nr->t1      = osk->protinfo.nr->t1;
	nr->t2      = osk->protinfo.nr->t2;
	nr->n2      = osk->protinfo.nr->n2;
	nr->t4      = osk->protinfo.nr->t4;
	nr->idle    = osk->protinfo.nr->idle;
	nr->window  = osk->protinfo.nr->window;

	nr->device  = osk->protinfo.nr->device;
	nr->bpqext  = osk->protinfo.nr->bpqext;

	return sk;
}

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

	if (sk == NULL) return 0;

	switch (sk->protinfo.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);
			sk->protinfo.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);
			sk->protinfo.nr->state   = NR_STATE_2;
			sk->state                = TCP_CLOSE;
			sk->shutdown            |= SEND_SHUTDOWN;
			sk->state_change(sk);
			sk->dead                 = 1;
			sk->destroy              = 1;
			sk->socket               = NULL;
			break;

		default:
			sk->socket = NULL;
			break;
	}

	sock->sk   = NULL;	

	return 0;
}

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

	if (sk->zapped == 0)
		return -EINVAL;

	if (addr_len < sizeof(struct sockaddr_ax25) || addr_len > sizeof(struct
full_sockaddr_ax25))
		return -EINVAL;

	if (addr_len < (addr->fsa_ax25.sax25_ndigis * sizeof(ax25_address) + sizeof(struct sockaddr_ax25)))
		return -EINVAL;

	if (addr->fsa_ax25.sax25_family != AF_NETROM)
		return -EINVAL;

	if ((dev = nr_dev_get(&addr->fsa_ax25.sax25_call)) == NULL) {
		SOCK_DEBUG(sk, "NET/ROM: bind failed: invalid node callsign\n");
		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))
			return -EACCES;
		sk->protinfo.nr->user_addr   = addr->fsa_digipeater[0];
		sk->protinfo.nr->source_addr = addr->fsa_ax25.sax25_call;
	} else {
		source = &addr->fsa_ax25.sax25_call;

		if ((user = ax25_findbyuid(current->euid)) == NULL) {
			if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE))
				return -EPERM;
			user = source;
		}

		sk->protinfo.nr->user_addr   = *user;
		sk->protinfo.nr->source_addr = *source;
	}

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

	sk->zapped = 0;
	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 sockaddr_ax25 *addr = (struct sockaddr_ax25 *)uaddr;
	ax25_address *user, *source = NULL;
	struct net_device *dev;

	if (sk->state == TCP_ESTABLISHED && sock->state == SS_CONNECTING) {
		sock->state = SS_CONNECTED;
		return 0;	/* Connect completed during a ERESTARTSYS event */
	}

	if (sk->state == TCP_CLOSE && sock->state == SS_CONNECTING) {
		sock->state = SS_UNCONNECTED;
		return -ECONNREFUSED;
	}

	if (sk->state == TCP_ESTABLISHED)
		return -EISCONN;	/* No reconnect on a seqpacket socket */

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

	if (addr_len != sizeof(struct sockaddr_ax25) && addr_len != sizeof(struct full_sockaddr_ax25))
		return -EINVAL;

	if (addr->sax25_family != AF_NETROM)
		return -EINVAL;

	if (sk->zapped) {	/* Must bind first - autobinding in this may or may not work */
		sk->zapped = 0;