af_ax25.c

linux 内核源代码

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

	if (maxlen < 1)
		return -EFAULT;

	valptr = (void *) &val;
	length = min_t(unsigned int, maxlen, sizeof(int));

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

	switch (optname) {
	case AX25_WINDOW:
		val = ax25->window;
		break;

	case AX25_T1:
		val = ax25->t1 / HZ;
		break;

	case AX25_T2:
		val = ax25->t2 / HZ;
		break;

	case AX25_N2:
		val = ax25->n2;
		break;

	case AX25_T3:
		val = ax25->t3 / HZ;
		break;

	case AX25_IDLE:
		val = ax25->idle / (60 * HZ);
		break;

	case AX25_BACKOFF:
		val = ax25->backoff;
		break;

	case AX25_EXTSEQ:
		val = (ax25->modulus == AX25_EMODULUS);
		break;

	case AX25_PIDINCL:
		val = ax25->pidincl;
		break;

	case AX25_IAMDIGI:
		val = ax25->iamdigi;
		break;

	case AX25_PACLEN:
		val = ax25->paclen;
		break;

	case SO_BINDTODEVICE:
		ax25_dev = ax25->ax25_dev;

		if (ax25_dev != NULL && ax25_dev->dev != NULL) {
			strlcpy(devname, ax25_dev->dev->name, sizeof(devname));
			length = strlen(devname) + 1;
		} else {
			*devname = '\0';
			length = 1;
		}

		valptr = (void *) devname;
		break;

	default:
		release_sock(sk);
		return -ENOPROTOOPT;
	}
	release_sock(sk);

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

	return copy_to_user(optval, valptr, length) ? -EFAULT : 0;
}

static int ax25_listen(struct socket *sock, int backlog)
{
	struct sock *sk = sock->sk;
	int res = 0;

	lock_sock(sk);
	if (sk->sk_type == SOCK_SEQPACKET && sk->sk_state != TCP_LISTEN) {
		sk->sk_max_ack_backlog = backlog;
		sk->sk_state           = TCP_LISTEN;
		goto out;
	}
	res = -EOPNOTSUPP;

out:
	release_sock(sk);

	return res;
}

/*
 * XXX: when creating ax25_sock we should update the .obj_size setting
 * below.
 */
static struct proto ax25_proto = {
	.name	  = "AX25",
	.owner	  = THIS_MODULE,
	.obj_size = sizeof(struct sock),
};

static int ax25_create(struct net *net, struct socket *sock, int protocol)
{
	struct sock *sk;
	ax25_cb *ax25;

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

	switch (sock->type) {
	case SOCK_DGRAM:
		if (protocol == 0 || protocol == PF_AX25)
			protocol = AX25_P_TEXT;
		break;

	case SOCK_SEQPACKET:
		switch (protocol) {
		case 0:
		case PF_AX25:	/* For CLX */
			protocol = AX25_P_TEXT;
			break;
		case AX25_P_SEGMENT:
#ifdef CONFIG_INET
		case AX25_P_ARP:
		case AX25_P_IP:
#endif
#ifdef CONFIG_NETROM
		case AX25_P_NETROM:
#endif
#ifdef CONFIG_ROSE
		case AX25_P_ROSE:
#endif
			return -ESOCKTNOSUPPORT;
#ifdef CONFIG_NETROM_MODULE
		case AX25_P_NETROM:
			if (ax25_protocol_is_registered(AX25_P_NETROM))
				return -ESOCKTNOSUPPORT;
#endif
#ifdef CONFIG_ROSE_MODULE
		case AX25_P_ROSE:
			if (ax25_protocol_is_registered(AX25_P_ROSE))
				return -ESOCKTNOSUPPORT;
#endif
		default:
			break;
		}
		break;

	case SOCK_RAW:
		break;
	default:
		return -ESOCKTNOSUPPORT;
	}

	sk = sk_alloc(net, PF_AX25, GFP_ATOMIC, &ax25_proto);
	if (sk == NULL)
		return -ENOMEM;

	ax25 = sk->sk_protinfo = ax25_create_cb();
	if (!ax25) {
		sk_free(sk);
		return -ENOMEM;
	}

	sock_init_data(sock, sk);

	sk->sk_destruct = ax25_free_sock;
	sock->ops    = &ax25_proto_ops;
	sk->sk_protocol = protocol;

	ax25->sk    = sk;

	return 0;
}

struct sock *ax25_make_new(struct sock *osk, struct ax25_dev *ax25_dev)
{
	struct sock *sk;
	ax25_cb *ax25, *oax25;

	sk = sk_alloc(osk->sk_net, PF_AX25, GFP_ATOMIC,	osk->sk_prot);
	if (sk == NULL)
		return NULL;

	if ((ax25 = ax25_create_cb()) == NULL) {
		sk_free(sk);
		return NULL;
	}

	switch (osk->sk_type) {
	case SOCK_DGRAM:
		break;
	case SOCK_SEQPACKET:
		break;
	default:
		sk_free(sk);
		ax25_cb_put(ax25);
		return NULL;
	}

	sock_init_data(NULL, sk);

	sk->sk_destruct = ax25_free_sock;
	sk->sk_type     = osk->sk_type;
	sk->sk_socket   = osk->sk_socket;
	sk->sk_priority = osk->sk_priority;
	sk->sk_protocol = osk->sk_protocol;
	sk->sk_rcvbuf   = osk->sk_rcvbuf;
	sk->sk_sndbuf   = osk->sk_sndbuf;
	sk->sk_state    = TCP_ESTABLISHED;
	sk->sk_sleep    = osk->sk_sleep;
	sock_copy_flags(sk, osk);

	oax25 = ax25_sk(osk);

	ax25->modulus = oax25->modulus;
	ax25->backoff = oax25->backoff;
	ax25->pidincl = oax25->pidincl;
	ax25->iamdigi = oax25->iamdigi;
	ax25->rtt     = oax25->rtt;
	ax25->t1      = oax25->t1;
	ax25->t2      = oax25->t2;
	ax25->t3      = oax25->t3;
	ax25->n2      = oax25->n2;
	ax25->idle    = oax25->idle;
	ax25->paclen  = oax25->paclen;
	ax25->window  = oax25->window;

	ax25->ax25_dev    = ax25_dev;
	ax25->source_addr = oax25->source_addr;

	if (oax25->digipeat != NULL) {
		ax25->digipeat = kmemdup(oax25->digipeat, sizeof(ax25_digi),
					 GFP_ATOMIC);
		if (ax25->digipeat == NULL) {
			sk_free(sk);
			ax25_cb_put(ax25);
			return NULL;
		}
	}

	sk->sk_protinfo = ax25;
	ax25->sk    = sk;

	return sk;
}

static int ax25_release(struct socket *sock)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25;

	if (sk == NULL)
		return 0;

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

	if (sk->sk_type == SOCK_SEQPACKET) {
		switch (ax25->state) {
		case AX25_STATE_0:
			release_sock(sk);
			ax25_disconnect(ax25, 0);
			lock_sock(sk);
			ax25_destroy_socket(ax25);
			break;

		case AX25_STATE_1:
		case AX25_STATE_2:
			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
			release_sock(sk);
			ax25_disconnect(ax25, 0);
			lock_sock(sk);
			ax25_destroy_socket(ax25);
			break;

		case AX25_STATE_3:
		case AX25_STATE_4:
			ax25_clear_queues(ax25);
			ax25->n2count = 0;

			switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
			case AX25_PROTO_STD_SIMPLEX:
			case AX25_PROTO_STD_DUPLEX:
				ax25_send_control(ax25,
						  AX25_DISC,
						  AX25_POLLON,
						  AX25_COMMAND);
				ax25_stop_t2timer(ax25);
				ax25_stop_t3timer(ax25);
				ax25_stop_idletimer(ax25);
				break;
#ifdef CONFIG_AX25_DAMA_SLAVE
			case AX25_PROTO_DAMA_SLAVE:
				ax25_stop_t3timer(ax25);
				ax25_stop_idletimer(ax25);
				break;
#endif
			}
			ax25_calculate_t1(ax25);
			ax25_start_t1timer(ax25);
			ax25->state = AX25_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;
		}
	} else {
		sk->sk_state     = TCP_CLOSE;
		sk->sk_shutdown |= SEND_SHUTDOWN;
		sk->sk_state_change(sk);
		ax25_destroy_socket(ax25);
	}

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

	return 0;
}

/*
 *	We support a funny extension here so you can (as root) give any callsign
 *	digipeated via a local address as source. This hack is obsolete now
 *	that we've implemented support for SO_BINDTODEVICE. It is however small
 *	and trivially backward compatible.
 */
static int ax25_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;
	ax25_dev *ax25_dev = NULL;
	ax25_uid_assoc *user;
	ax25_address call;
	ax25_cb *ax25;
	int err = 0;

	if (addr_len != sizeof(struct sockaddr_ax25) &&
	    addr_len != sizeof(struct full_sockaddr_ax25)) {
		/* support for old structure may go away some time */
		if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
		    (addr_len > sizeof(struct full_sockaddr_ax25))) {
			return -EINVAL;
	}

		printk(KERN_WARNING "ax25_bind(): %s uses old (6 digipeater) socket structure.\n",
			current->comm);
	}

	if (addr->fsa_ax25.sax25_family != AF_AX25)
		return -EINVAL;

	user = ax25_findbyuid(current->euid);
	if (user) {
		call = user->call;
		ax25_uid_put(user);
	} else {
		if (ax25_uid_policy && !capable(CAP_NET_ADMIN))
			return -EACCES;

		call = addr->fsa_ax25.sax25_call;
	}

	lock_sock(sk);

	ax25 = ax25_sk(sk);
	if (!sock_flag(sk, SOCK_ZAPPED)) {
		err = -EINVAL;
		goto out;
	}

	ax25->source_addr = call;

	/*
	 * User already set interface with SO_BINDTODEVICE
	 */
	if (ax25->ax25_dev != NULL)
		goto done;

	if (addr_len > sizeof(struct sockaddr_ax25) && addr->fsa_ax25.sax25_ndigis == 1) {
		if (ax25cmp(&addr->fsa_digipeater[0], &null_ax25_address) != 0 &&
		    (ax25_dev = ax25_addr_ax25dev(&addr->fsa_digipeater[0])) == NULL) {
			err = -EADDRNOTAVAIL;
			goto out;
		}
	} else {
		if ((ax25_dev = ax25_addr_ax25dev(&addr->fsa_ax25.sax25_call)) == NULL) {
			err = -EADDRNOTAVAIL;
			goto out;
		}
	}

	if (ax25_dev != NULL)
		ax25_fillin_cb(ax25, ax25_dev);

done:
	ax25_cb_add(ax25);
	sock_reset_flag(sk, SOCK_ZAPPED);

out:
	release_sock(sk);

	return 0;
}

/*
 *	FIXME: nonblock behaviour looks like it may have a bug.
 */
static int __must_check ax25_connect(struct socket *sock,
	struct sockaddr *uaddr, int addr_len, int flags)
{
	struct sock *sk = sock->sk;
	ax25_cb *ax25 = ax25_sk(sk), *ax25t;
	struct full_sockaddr_ax25 *fsa = (struct full_sockaddr_ax25 *)uaddr;
	ax25_digi *digi = NULL;
	int ct = 0, err = 0;

	/*
	 * some sanity checks. code further down depends on this
	 */

	if (addr_len == sizeof(struct sockaddr_ax25))
		/* support for this will go away in early 2.5.x
		 * ax25_connect(): uses obsolete socket structure
		 */
		;
	else if (addr_len != sizeof(struct full_sockaddr_ax25))
		/* support for old structure may go away some time
		 * ax25_connect(): uses old (6 digipeater) socket structure.
		 */
		if ((addr_len < sizeof(struct sockaddr_ax25) + sizeof(ax25_address) * 6) ||
		    (addr_len > sizeof(struct full_sockaddr_ax25)))
			return -EINVAL;


	if (fsa->fsa_ax25.sax25_family != AF_AX25)
		return -EINVAL;

	lock_sock(sk);

	/* deal with restarts */
	if (sock->state == SS_CONNECTING) {
		switch (sk->sk_state) {
		case TCP_SYN_SENT: /* still trying */
			err = -EINPROGRESS;
			goto out_release;

		case TCP_ESTABLISHED: /* connection established */
			sock->state = SS_CONNECTED;
			goto out_release;

		case TCP_CLOSE: /* connection refused */
			sock->state = SS_UNCONNECTED;
			err = -ECONNREFUSED;
			goto out_release;
		}
	}

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

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

	kfree(ax25->digipeat);
	ax25->digipeat = NULL;

	/*
	 *	Handle digi-peaters to be used.
	 */
	if (addr_len > sizeof(struct sockaddr_ax25) &&
	    fsa->fsa_ax25.sax25_ndigis != 0) {
		/* Valid number of digipeaters ? */
		if (fsa->fsa_ax25.sax25_ndigis < 1 || fsa->fsa_ax25.sax25_ndigis > AX25_MAX_DIGIS) {
			err = -EINVAL;
			goto out_release;
		}

		if ((digi = kmalloc(sizeof(ax25_digi), GFP_KERNEL)) == NULL) {
			err = -ENOBUFS;
			goto out_release;
		}

		digi->ndigi      = fsa->fsa_ax25.sax25_ndigis;
		digi->lastrepeat = -1;

		while (ct < fsa->fsa_ax25.sax25_ndigis) {
			if ((fsa->fsa_digipeater[ct].ax25_call[6] &
			     AX25_HBIT) && ax25->iamdigi) {
				digi->repeated[ct] = 1;
				digi->lastrepeat   = ct;
			} else {
				digi->repeated[ct] = 0;
			}
			digi->calls[ct] = fsa->fsa_digipeater[ct];
			ct++;
		}
	}

	/*
	 *	Must bind first - autobinding in this may or may not work. If
	 *	the socket is already bound, check to see if the device has
	 *	been filled in, error if it hasn't.
	 */
	if (sock_flag(sk, SOCK_ZAPPED)) {
		/* check if we can remove this feature. It is broken. */
		printk(KERN_WARNING "ax25_connect(): %s uses autobind, please contact [e-mail]\n",
			current->comm);
		if ((err = ax25_rt_autobind(ax25, &fsa->fsa_ax25.sax25_call)) < 0) {
			kfree(digi);
			goto out_release;
		}

		ax25_fillin_cb(ax25, ax25->ax25_dev);
		ax25_cb_add(ax25);
	} else {
		if (ax25->ax25_dev == NULL) {
			kfree(digi);
			err = -EHOSTUNREACH;
			goto out_release;
		}
	}

	if (sk->sk_type == SOCK_SEQPACKET &&
	    (ax25t=ax25_find_cb(&ax25->source_addr, &fsa->fsa_ax25.sax25_call, digi,
			 ax25->ax25_dev->dev))) {
		kfree(digi);
		err = -EADDRINUSE;		/* Already such a connection */
		ax25_cb_put(ax25t);
		goto out_release;
	}

	ax25->dest_addr = fsa->fsa_ax25.sax25_call;
	ax25->digipeat  = digi;

	/* First the easy one */
	if (sk->sk_type != SOCK_SEQPACKET) {
		sock->state = SS_CONNECTED;
		sk->sk_state   = TCP_ESTABLISHED;
		goto out_release;
	}

	/* Move to connecting socket, ax.25 lapb WAIT_UA.. */
	sock->state        = SS_CONNECTING;
	sk->sk_state          = TCP_SYN_SENT;

	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
	case AX25_PROTO_STD_SIMPLEX:
	case AX25_PROTO_STD_DUPLEX:
		ax25_std_establish_data_link(ax25);
		break;

#ifdef CONFIG_AX25_DAMA_SLAVE
	case AX25_PROTO_DAMA_SLAVE:
		ax25->modulus = AX25_MODULUS;
		ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
		if (ax25->ax25_dev->dama.slave)
			ax25_ds_establish_data_link(ax25);
		else
			ax25_std_establish_data_link(ax25);
		break;
#endif
	}

	ax25->state = AX25_STATE_1;

	ax25_start_heartbeat(ax25);

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

	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) {
		/* Not in ABM, not in WAIT_UA -> failed */
		sock->state = SS_UNCONNECTED;
		err = sock_error(sk);	/* Always set at this point */
		goto out_release;
	}

	sock->state = SS_CONNECTED;

	err = 0;
out_release:
	release_sock(sk);

	return err;
}

static int ax25_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 (sock->state != SS_UNCONNECTED)
		return -EINVAL;

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

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

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

	/*
	 *	The read 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)