af_ax25.c

linux 内核源代码

/*
 * 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 (C) Alan Cox GW4PTS ([e-mail])
 * Copyright (C) Jonathan Naylor G4KLX ([e-mail])
 * Copyright (C) Darryl Miles G7LED ([e-mail])
 * Copyright (C) Steven Whitehouse GW7RRM ([e-mail])
 * Copyright (C) Joerg Reuter DL1BKE ([e-mail])
 * Copyright (C) Hans-Joachim Hetscher DD8NE ([e-mail])
 * Copyright (C) Hans Alblas PE1AYX ([e-mail])
 * Copyright (C) Frederic Rible F1OAT ([e-mail])
 */
#include <linux/capability.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 <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 <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <net/net_namespace.h>
#include <net/tcp_states.h>
#include <net/ip.h>
#include <net/arp.h>



HLIST_HEAD(ax25_list);
DEFINE_SPINLOCK(ax25_list_lock);

static const struct proto_ops ax25_proto_ops;

static void ax25_free_sock(struct sock *sk)
{
	ax25_cb_put(ax25_sk(sk));
}

/*
 *	Socket removal during an interrupt is now safe.
 */
static void ax25_cb_del(ax25_cb *ax25)
{
	if (!hlist_unhashed(&ax25->ax25_node)) {
		spin_lock_bh(&ax25_list_lock);
		hlist_del_init(&ax25->ax25_node);
		spin_unlock_bh(&ax25_list_lock);
		ax25_cb_put(ax25);
	}
}

/*
 *	Kill all bound sockets on a dropped device.
 */
static void ax25_kill_by_device(struct net_device *dev)
{
	ax25_dev *ax25_dev;
	ax25_cb *s;
	struct hlist_node *node;

	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
		return;

	spin_lock_bh(&ax25_list_lock);
again:
	ax25_for_each(s, node, &ax25_list) {
		if (s->ax25_dev == ax25_dev) {
			s->ax25_dev = NULL;
			spin_unlock_bh(&ax25_list_lock);
			ax25_disconnect(s, ENETUNREACH);
			spin_lock_bh(&ax25_list_lock);

			/* The entry could have been deleted from the
			 * list meanwhile and thus the next pointer is
			 * no longer valid.  Play it safe and restart
			 * the scan.  Forward progress is ensured
			 * because we set s->ax25_dev to NULL and we
			 * are never passed a NULL 'dev' argument.
			 */
			goto again;
		}
	}
	spin_unlock_bh(&ax25_list_lock);
}

/*
 *	Handle device status changes.
 */
static int ax25_device_event(struct notifier_block *this, unsigned long event,
	void *ptr)
{
	struct net_device *dev = (struct net_device *)ptr;

	if (dev->nd_net != &init_net)
		return NOTIFY_DONE;

	/* Reject non AX.25 devices */
	if (dev->type != ARPHRD_AX25)
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UP:
		ax25_dev_device_up(dev);
		break;
	case NETDEV_DOWN:
		ax25_kill_by_device(dev);
		ax25_rt_device_down(dev);
		ax25_dev_device_down(dev);
		break;
	default:
		break;
	}

	return NOTIFY_DONE;
}

/*
 *	Add a socket to the bound sockets list.
 */
void ax25_cb_add(ax25_cb *ax25)
{
	spin_lock_bh(&ax25_list_lock);
	ax25_cb_hold(ax25);
	hlist_add_head(&ax25->ax25_node, &ax25_list);
	spin_unlock_bh(&ax25_list_lock);
}

/*
 *	Find a socket that wants to accept the SABM we have just
 *	received.
 */
struct sock *ax25_find_listener(ax25_address *addr, int digi,
	struct net_device *dev, int type)
{
	ax25_cb *s;
	struct hlist_node *node;

	spin_lock(&ax25_list_lock);
	ax25_for_each(s, node, &ax25_list) {
		if ((s->iamdigi && !digi) || (!s->iamdigi && digi))
			continue;
		if (s->sk && !ax25cmp(&s->source_addr, addr) &&
		    s->sk->sk_type == type && s->sk->sk_state == TCP_LISTEN) {
			/* If device is null we match any device */
			if (s->ax25_dev == NULL || s->ax25_dev->dev == dev) {
				sock_hold(s->sk);
				spin_unlock(&ax25_list_lock);
				return s->sk;
			}
		}
	}
	spin_unlock(&ax25_list_lock);

	return NULL;
}

/*
 *	Find an AX.25 socket given both ends.
 */
struct sock *ax25_get_socket(ax25_address *my_addr, ax25_address *dest_addr,
	int type)
{
	struct sock *sk = NULL;
	ax25_cb *s;
	struct hlist_node *node;

	spin_lock(&ax25_list_lock);
	ax25_for_each(s, node, &ax25_list) {
		if (s->sk && !ax25cmp(&s->source_addr, my_addr) &&
		    !ax25cmp(&s->dest_addr, dest_addr) &&
		    s->sk->sk_type == type) {
			sk = s->sk;
			sock_hold(sk);
			break;
		}
	}

	spin_unlock(&ax25_list_lock);

	return sk;
}

/*
 *	Find an AX.25 control block given both ends. It will only pick up
 *	floating AX.25 control blocks or non Raw socket bound control blocks.
 */
ax25_cb *ax25_find_cb(ax25_address *src_addr, ax25_address *dest_addr,
	ax25_digi *digi, struct net_device *dev)
{
	ax25_cb *s;
	struct hlist_node *node;

	spin_lock_bh(&ax25_list_lock);
	ax25_for_each(s, node, &ax25_list) {
		if (s->sk && s->sk->sk_type != SOCK_SEQPACKET)
			continue;
		if (s->ax25_dev == NULL)
			continue;
		if (ax25cmp(&s->source_addr, src_addr) == 0 && ax25cmp(&s->dest_addr, dest_addr) == 0 && s->ax25_dev->dev == dev) {
			if (digi != NULL && digi->ndigi != 0) {
				if (s->digipeat == NULL)
					continue;
				if (ax25digicmp(s->digipeat, digi) != 0)
					continue;
			} else {
				if (s->digipeat != NULL && s->digipeat->ndigi != 0)
					continue;
			}
			ax25_cb_hold(s);
			spin_unlock_bh(&ax25_list_lock);

			return s;
		}
	}
	spin_unlock_bh(&ax25_list_lock);

	return NULL;
}

EXPORT_SYMBOL(ax25_find_cb);

void ax25_send_to_raw(ax25_address *addr, struct sk_buff *skb, int proto)
{
	ax25_cb *s;
	struct sk_buff *copy;
	struct hlist_node *node;

	spin_lock(&ax25_list_lock);
	ax25_for_each(s, node, &ax25_list) {
		if (s->sk != NULL && ax25cmp(&s->source_addr, addr) == 0 &&
		    s->sk->sk_type == SOCK_RAW &&
		    s->sk->sk_protocol == proto &&
		    s->ax25_dev->dev == skb->dev &&
		    atomic_read(&s->sk->sk_rmem_alloc) <= s->sk->sk_rcvbuf) {
			if ((copy = skb_clone(skb, GFP_ATOMIC)) == NULL)
				continue;
			if (sock_queue_rcv_skb(s->sk, copy) != 0)
				kfree_skb(copy);
		}
	}
	spin_unlock(&ax25_list_lock);
}

/*
 *	Deferred destroy.
 */
void ax25_destroy_socket(ax25_cb *);

/*
 *	Handler for deferred kills.
 */
static void ax25_destroy_timer(unsigned long data)
{
	ax25_cb *ax25=(ax25_cb *)data;
	struct sock *sk;

	sk=ax25->sk;

	bh_lock_sock(sk);
	sock_hold(sk);
	ax25_destroy_socket(ax25);
	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 ax25_destroy_socket(ax25_cb *ax25)
{
	struct sk_buff *skb;

	ax25_cb_del(ax25);

	ax25_stop_heartbeat(ax25);
	ax25_stop_t1timer(ax25);
	ax25_stop_t2timer(ax25);
	ax25_stop_t3timer(ax25);
	ax25_stop_idletimer(ax25);

	ax25_clear_queues(ax25);	/* Flush the queues */

	if (ax25->sk != NULL) {
		while ((skb = skb_dequeue(&ax25->sk->sk_receive_queue)) != NULL) {
			if (skb->sk != ax25->sk) {
				/* A pending connection */
				ax25_cb *sax25 = ax25_sk(skb->sk);

				/* Queue the unaccepted socket for death */
				sock_orphan(skb->sk);

				ax25_start_heartbeat(sax25);
				sax25->state = AX25_STATE_0;
			}

			kfree_skb(skb);
		}
		skb_queue_purge(&ax25->sk->sk_write_queue);
	}

	if (ax25->sk != NULL) {
		if (atomic_read(&ax25->sk->sk_wmem_alloc) ||
		    atomic_read(&ax25->sk->sk_rmem_alloc)) {
			/* Defer: outstanding buffers */
			init_timer(&ax25->dtimer);
			ax25->dtimer.expires  = jiffies + 2 * HZ;
			ax25->dtimer.function = ax25_destroy_timer;
			ax25->dtimer.data     = (unsigned long)ax25;
			add_timer(&ax25->dtimer);
		} else {
			struct sock *sk=ax25->sk;
			ax25->sk=NULL;
			sock_put(sk);
		}
	} else {
		ax25_cb_put(ax25);
	}
}

/*
 * dl1bke 960311: set parameters for existing AX.25 connections,
 *		  includes a KILL command to abort any connection.
 *		  VERY useful for debugging ;-)
 */
static int ax25_ctl_ioctl(const unsigned int cmd, void __user *arg)
{
	struct ax25_ctl_struct ax25_ctl;
	ax25_digi digi;
	ax25_dev *ax25_dev;
	ax25_cb *ax25;
	unsigned int k;

	if (copy_from_user(&ax25_ctl, arg, sizeof(ax25_ctl)))
		return -EFAULT;

	if ((ax25_dev = ax25_addr_ax25dev(&ax25_ctl.port_addr)) == NULL)
		return -ENODEV;

	if (ax25_ctl.digi_count > AX25_MAX_DIGIS)
		return -EINVAL;

	digi.ndigi = ax25_ctl.digi_count;
	for (k = 0; k < digi.ndigi; k++)
		digi.calls[k] = ax25_ctl.digi_addr[k];

	if ((ax25 = ax25_find_cb(&ax25_ctl.source_addr, &ax25_ctl.dest_addr, &digi, ax25_dev->dev)) == NULL)
		return -ENOTCONN;

	switch (ax25_ctl.cmd) {
	case AX25_KILL:
		ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
#ifdef CONFIG_AX25_DAMA_SLAVE
		if (ax25_dev->dama.slave && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
			ax25_dama_off(ax25);
#endif
		ax25_disconnect(ax25, ENETRESET);
		break;

	case AX25_WINDOW:
		if (ax25->modulus == AX25_MODULUS) {
			if (ax25_ctl.arg < 1 || ax25_ctl.arg > 7)
				return -EINVAL;
		} else {
			if (ax25_ctl.arg < 1 || ax25_ctl.arg > 63)
				return -EINVAL;
		}
		ax25->window = ax25_ctl.arg;
		break;

	case AX25_T1:
		if (ax25_ctl.arg < 1)
			return -EINVAL;
		ax25->rtt = (ax25_ctl.arg * HZ) / 2;
		ax25->t1  = ax25_ctl.arg * HZ;
		break;

	case AX25_T2:
		if (ax25_ctl.arg < 1)
			return -EINVAL;
		ax25->t2 = ax25_ctl.arg * HZ;
		break;

	case AX25_N2:
		if (ax25_ctl.arg < 1 || ax25_ctl.arg > 31)
			return -EINVAL;
		ax25->n2count = 0;
		ax25->n2 = ax25_ctl.arg;
		break;

	case AX25_T3:
		if (ax25_ctl.arg < 0)
			return -EINVAL;
		ax25->t3 = ax25_ctl.arg * HZ;
		break;

	case AX25_IDLE:
		if (ax25_ctl.arg < 0)
			return -EINVAL;
		ax25->idle = ax25_ctl.arg * 60 * HZ;
		break;

	case AX25_PACLEN:
		if (ax25_ctl.arg < 16 || ax25_ctl.arg > 65535)
			return -EINVAL;
		ax25->paclen = ax25_ctl.arg;
		break;

	default:
		return -EINVAL;
	  }

	return 0;
}

static void ax25_fillin_cb_from_dev(ax25_cb *ax25, ax25_dev *ax25_dev)
{
	ax25->rtt     = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T1]) / 2;
	ax25->t1      = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T1]);
	ax25->t2      = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T2]);
	ax25->t3      = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_T3]);
	ax25->n2      = ax25_dev->values[AX25_VALUES_N2];
	ax25->paclen  = ax25_dev->values[AX25_VALUES_PACLEN];
	ax25->idle    = msecs_to_jiffies(ax25_dev->values[AX25_VALUES_IDLE]);
	ax25->backoff = ax25_dev->values[AX25_VALUES_BACKOFF];

	if (ax25_dev->values[AX25_VALUES_AXDEFMODE]) {
		ax25->modulus = AX25_EMODULUS;
		ax25->window  = ax25_dev->values[AX25_VALUES_EWINDOW];
	} else {
		ax25->modulus = AX25_MODULUS;
		ax25->window  = ax25_dev->values[AX25_VALUES_WINDOW];
	}
}

/*
 *	Fill in a created AX.25 created control block with the default
 *	values for a particular device.
 */
void ax25_fillin_cb(ax25_cb *ax25, ax25_dev *ax25_dev)
{
	ax25->ax25_dev = ax25_dev;

	if (ax25->ax25_dev != NULL) {
		ax25_fillin_cb_from_dev(ax25, ax25_dev);
		return;
	}

	/*
	 * No device, use kernel / AX.25 spec default values
	 */
	ax25->rtt     = msecs_to_jiffies(AX25_DEF_T1) / 2;
	ax25->t1      = msecs_to_jiffies(AX25_DEF_T1);
	ax25->t2      = msecs_to_jiffies(AX25_DEF_T2);
	ax25->t3      = msecs_to_jiffies(AX25_DEF_T3);
	ax25->n2      = AX25_DEF_N2;
	ax25->paclen  = AX25_DEF_PACLEN;
	ax25->idle    = msecs_to_jiffies(AX25_DEF_IDLE);
	ax25->backoff = AX25_DEF_BACKOFF;

	if (AX25_DEF_AXDEFMODE) {
		ax25->modulus = AX25_EMODULUS;
		ax25->window  = AX25_DEF_EWINDOW;
	} else {
		ax25->modulus = AX25_MODULUS;
		ax25->window  = AX25_DEF_WINDOW;
	}
}

/*
 * Create an empty AX.25 control block.
 */
ax25_cb *ax25_create_cb(void)
{
	ax25_cb *ax25;

	if ((ax25 = kzalloc(sizeof(*ax25), GFP_ATOMIC)) == NULL)
		return NULL;

	atomic_set(&ax25->refcount, 1);

	skb_queue_head_init(&ax25->write_queue);
	skb_queue_head_init(&ax25->frag_queue);
	skb_queue_head_init(&ax25->ack_queue);
	skb_queue_head_init(&ax25->reseq_queue);

	init_timer(&ax25->timer);
	init_timer(&ax25->t1timer);
	init_timer(&ax25->t2timer);
	init_timer(&ax25->t3timer);
	init_timer(&ax25->idletimer);

	ax25_fillin_cb(ax25, NULL);

	ax25->state = AX25_STATE_0;

	return ax25;
}

/*
 *	Handling for system calls applied via the various interfaces to an
 *	AX25 socket object
 */

static int ax25_setsockopt(struct socket *sock, int level, int optname,
	char __user *optval, int optlen)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25;
	struct net_device *dev;
	char devname[IFNAMSIZ];
	int opt, res = 0;

	if (level != SOL_AX25)
		return -ENOPROTOOPT;

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

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

	lock_sock(sk);
	ax25 = ax25_sk(sk);

	switch (optname) {
	case AX25_WINDOW:
		if (ax25->modulus == AX25_MODULUS) {
			if (opt < 1 || opt > 7) {
				res = -EINVAL;
				break;
			}
		} else {
			if (opt < 1 || opt > 63) {
				res = -EINVAL;
				break;
			}
		}
		ax25->window = opt;
		break;

	case AX25_T1:
		if (opt < 1) {
			res = -EINVAL;
			break;
		}
		ax25->rtt = (opt * HZ) / 2;
		ax25->t1  = opt * HZ;
		break;

	case AX25_T2:
		if (opt < 1) {
			res = -EINVAL;
			break;
		}
		ax25->t2 = opt * HZ;
		break;

	case AX25_N2:
		if (opt < 1 || opt > 31) {
			res = -EINVAL;
			break;
		}
		ax25->n2 = opt;
		break;

	case AX25_T3:
		if (opt < 1) {
			res = -EINVAL;
			break;
		}
		ax25->t3 = opt * HZ;
		break;

	case AX25_IDLE:
		if (opt < 0) {
			res = -EINVAL;
			break;
		}
		ax25->idle = opt * 60 * HZ;
		break;

	case AX25_BACKOFF:
		if (opt < 0 || opt > 2) {
			res = -EINVAL;
			break;
		}
		ax25->backoff = opt;
		break;

	case AX25_EXTSEQ:
		ax25->modulus = opt ? AX25_EMODULUS : AX25_MODULUS;
		break;

	case AX25_PIDINCL:
		ax25->pidincl = opt ? 1 : 0;
		break;

	case AX25_IAMDIGI:
		ax25->iamdigi = opt ? 1 : 0;
		break;

	case AX25_PACLEN:
		if (opt < 16 || opt > 65535) {
			res = -EINVAL;
			break;
		}
		ax25->paclen = opt;
		break;

	case SO_BINDTODEVICE:
		if (optlen > IFNAMSIZ)
			optlen=IFNAMSIZ;
		if (copy_from_user(devname, optval, optlen)) {
		res = -EFAULT;
			break;
		}

		dev = dev_get_by_name(&init_net, devname);
		if (dev == NULL) {
			res = -ENODEV;
			break;
		}

		if (sk->sk_type == SOCK_SEQPACKET &&
		   (sock->state != SS_UNCONNECTED ||
		    sk->sk_state == TCP_LISTEN)) {
			res = -EADDRNOTAVAIL;
			dev_put(dev);
			break;
		}

		ax25->ax25_dev = ax25_dev_ax25dev(dev);
		ax25_fillin_cb(ax25, ax25->ax25_dev);
		break;

	default:
		res = -ENOPROTOOPT;
	}
	release_sock(sk);

	return res;
}

static int ax25_getsockopt(struct socket *sock, int level, int optname,
	char __user *optval, int __user *optlen)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25;
	struct ax25_dev *ax25_dev;
	char devname[IFNAMSIZ];
	void *valptr;
	int val = 0;
	int maxlen, length;

	if (level != SOL_AX25)
		return -ENOPROTOOPT;