af_x25.c

之前积累的一个X25在LINUX下的协议实现代码,现在估计应该比较少见了,应该是收藏的东西

	if (msg->msg_flags & MSG_OOB)
		skb_queue_tail(&x25->interrupt_out_queue, skb);
	else {
	        len = x25_output(sk, skb);
		if (len < 0)
			kfree_skb(skb);
		else if (x25->qbitincl)
			len++;
	}

	/*
	 * lock_sock() is currently only used to serialize this x25_kick()
	 * against input-driven x25_kick() calls. It currently only blocks
	 * incoming packets for this socket and does not protect against
	 * any other socket state changes and is not called from anywhere
	 * else. As x25_kick() cannot block and as long as all socket
	 * operations are BKL-wrapped, we don't need take to care about
	 * purging the backlog queue in x25_release().
	 *
	 * Using lock_sock() to protect all socket operations entirely
	 * (and making the whole x25 stack SMP aware) unfortunately would
	 * require major changes to {send,recv}msg and skb allocation methods.
	 * -> 2.5 ;)
	 */
	lock_sock(sk);
	x25_kick(sk);
	release_sock(sk);
	rc = len;
out:
	return rc;
out_kfree_skb:
	kfree_skb(skb);
	goto out;
}


static int x25_recvmsg(struct kiocb *iocb, struct socket *sock,
		       struct msghdr *msg, size_t size,
		       int flags)
{
	struct sock *sk = sock->sk;
	struct x25_sock *x25 = x25_sk(sk);
	struct sockaddr_x25 *sx25 = (struct sockaddr_x25 *)msg->msg_name;
	size_t copied;
	int qbit;
	struct sk_buff *skb;
	unsigned char *asmptr;
	int rc = -ENOTCONN;

	/*
	 * This works for seqpacket too. The receiver has ordered the queue for
	 * us! We do one quick check first though
	 */
	if (sk->sk_state != TCP_ESTABLISHED)
		goto out;

	if (flags & MSG_OOB) {
		rc = -EINVAL;
		if (sock_flag(sk, SOCK_URGINLINE) ||
		    !skb_peek(&x25->interrupt_in_queue))
			goto out;

		skb = skb_dequeue(&x25->interrupt_in_queue);

		skb_pull(skb, X25_STD_MIN_LEN);

		/*
		 *	No Q bit information on Interrupt data.
		 */
		if (x25->qbitincl) {
			asmptr  = skb_push(skb, 1);
			*asmptr = 0x00;
		}

		msg->msg_flags |= MSG_OOB;
	} else {
		/* Now we can treat all alike */
		skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
					flags & MSG_DONTWAIT, &rc);
		if (!skb)
			goto out;

		qbit = (skb->data[0] & X25_Q_BIT) == X25_Q_BIT;

		skb_pull(skb, x25->neighbour->extended ?
				X25_EXT_MIN_LEN : X25_STD_MIN_LEN);

		if (x25->qbitincl) {
			asmptr  = skb_push(skb, 1);
			*asmptr = qbit;
		}
	}

	skb->h.raw = skb->data;

	copied = skb->len;

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

	/* Currently, each datagram always contains a complete record */ 
	msg->msg_flags |= MSG_EOR;

	rc = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
	if (rc)
		goto out_free_dgram;

	if (sx25) {
		sx25->sx25_family = AF_X25;
		sx25->sx25_addr   = x25->dest_addr;
	}

	msg->msg_namelen = sizeof(struct sockaddr_x25);

	lock_sock(sk);
	x25_check_rbuf(sk);
	release_sock(sk);
	rc = copied;
out_free_dgram:
	skb_free_datagram(sk, skb);
out:
	return rc;
}


static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;
	struct x25_sock *x25 = x25_sk(sk);
	void __user *argp = (void __user *)arg;
	int rc;

	switch (cmd) {
		case TIOCOUTQ: {
			int amount = sk->sk_sndbuf -
				     atomic_read(&sk->sk_wmem_alloc);
			if (amount < 0)
				amount = 0;
			rc = put_user(amount, (unsigned int __user *)argp);
			break;
		}

		case TIOCINQ: {
			struct sk_buff *skb;
			int amount = 0;
			/*
			 * 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;
			rc = put_user(amount, (unsigned int __user *)argp);
			break;
		}

		case SIOCGSTAMP:
			rc = -EINVAL;
			if (sk)
				rc = sock_get_timestamp(sk, 
						(struct timeval __user *)argp); 
			break;
		case SIOCGIFADDR:
		case SIOCSIFADDR:
		case SIOCGIFDSTADDR:
		case SIOCSIFDSTADDR:
		case SIOCGIFBRDADDR:
		case SIOCSIFBRDADDR:
		case SIOCGIFNETMASK:
		case SIOCSIFNETMASK:
		case SIOCGIFMETRIC:
		case SIOCSIFMETRIC:
			rc = -EINVAL;
			break;
		case SIOCADDRT:
		case SIOCDELRT:
			rc = -EPERM;
			if (!capable(CAP_NET_ADMIN))
				break;
			rc = x25_route_ioctl(cmd, argp);
			break;
		case SIOCX25GSUBSCRIP:
			rc = x25_subscr_ioctl(cmd, argp);
			break;
		case SIOCX25SSUBSCRIP:
			rc = -EPERM;
			if (!capable(CAP_NET_ADMIN))
				break;
			rc = x25_subscr_ioctl(cmd, argp);
			break;
		case SIOCX25GFACILITIES: {
			struct x25_facilities fac = x25->facilities;
			rc = copy_to_user(argp, &fac,
					  sizeof(fac)) ? -EFAULT : 0;
			break;
		}

		case SIOCX25SFACILITIES: {
			struct x25_facilities facilities;
			rc = -EFAULT;
			if (copy_from_user(&facilities, argp,
					   sizeof(facilities)))
				break;
			rc = -EINVAL;
			if (sk->sk_state != TCP_LISTEN &&
			    sk->sk_state != TCP_CLOSE)
				break;
			if (facilities.pacsize_in < X25_PS16 ||
			    facilities.pacsize_in > X25_PS4096)
				break;
			if (facilities.pacsize_out < X25_PS16 ||
			    facilities.pacsize_out > X25_PS4096)
				break;
			if (facilities.winsize_in < 1 ||
			    facilities.winsize_in > 127)
				break;
			if (facilities.throughput < 0x03 ||
			    facilities.throughput > 0xDD)
				break;
			if (facilities.reverse &&
				(facilities.reverse | 0x81)!= 0x81)
				break;
			x25->facilities = facilities;
			rc = 0;
			break;
		}

		case SIOCX25GDTEFACILITIES: {
 			rc = copy_to_user(argp, &x25->dte_facilities,
						sizeof(x25->dte_facilities));
			if (rc)
				rc = -EFAULT;
 			break;
 		}

	 	case SIOCX25SDTEFACILITIES: {
	 		struct x25_dte_facilities dtefacs;
	 		rc = -EFAULT;
		 	if (copy_from_user(&dtefacs, argp, sizeof(dtefacs)))
				break;
			rc = -EINVAL;
			if (sk->sk_state != TCP_LISTEN &&
					sk->sk_state != TCP_CLOSE)
				break;
			if (dtefacs.calling_len > X25_MAX_AE_LEN)
				break;
			if (dtefacs.calling_ae == NULL)
				break;
			if (dtefacs.called_len > X25_MAX_AE_LEN)
				break;
			if (dtefacs.called_ae == NULL)
				break;
			x25->dte_facilities = dtefacs;
			rc = 0;
			break;
		}

		case SIOCX25GCALLUSERDATA: {
			struct x25_calluserdata cud = x25->calluserdata;
			rc = copy_to_user(argp, &cud,
					  sizeof(cud)) ? -EFAULT : 0;
			break;
		}

		case SIOCX25SCALLUSERDATA: {
			struct x25_calluserdata calluserdata;

			rc = -EFAULT;
			if (copy_from_user(&calluserdata, argp,
					   sizeof(calluserdata)))
				break;
			rc = -EINVAL;
			if (calluserdata.cudlength > X25_MAX_CUD_LEN)
				break;
			x25->calluserdata = calluserdata;
			rc = 0;
			break;
		}

		case SIOCX25GCAUSEDIAG: {
			struct x25_causediag causediag;
			causediag = x25->causediag;
			rc = copy_to_user(argp, &causediag,
					  sizeof(causediag)) ? -EFAULT : 0;
			break;
		}

		case SIOCX25SCUDMATCHLEN: {
			struct x25_subaddr sub_addr;
			rc = -EINVAL;
			if(sk->sk_state != TCP_CLOSE)
				break;
			rc = -EFAULT;
			if (copy_from_user(&sub_addr, argp,
					sizeof(sub_addr)))
				break;
		 	rc = -EINVAL;
			if(sub_addr.cudmatchlength > X25_MAX_CUD_LEN)
				break;
			x25->cudmatchlength = sub_addr.cudmatchlength;
			rc = 0;
			break;
		}

		case SIOCX25CALLACCPTAPPRV: {
			rc = -EINVAL;
			if (sk->sk_state != TCP_CLOSE)
				break;
			x25->accptapprv = X25_ALLOW_ACCPT_APPRV;
			rc = 0;
			break;
		}

		case SIOCX25SENDCALLACCPT:  {
			rc = -EINVAL;
			if (sk->sk_state != TCP_ESTABLISHED)
				break;
			if (x25->accptapprv)	/* must call accptapprv above */
				break;
			x25_write_internal(sk, X25_CALL_ACCEPTED);
			x25->state = X25_STATE_3;
			rc = 0;
			break;
		}

 		default:
			rc = -ENOIOCTLCMD;
			break;
	}

	return rc;
}

static struct net_proto_family x25_family_ops = {
	.family =	AF_X25,
	.create =	x25_create,
	.owner	=	THIS_MODULE,
};

#ifdef CONFIG_COMPAT
static int compat_x25_subscr_ioctl(unsigned int cmd,
		struct compat_x25_subscrip_struct __user *x25_subscr32)
{
	struct compat_x25_subscrip_struct x25_subscr;
	struct x25_neigh *nb;
	struct net_device *dev;
	int rc = -EINVAL;

	rc = -EFAULT;
	if (copy_from_user(&x25_subscr, x25_subscr32, sizeof(*x25_subscr32)))
		goto out;

	rc = -EINVAL;
	dev = x25_dev_get(x25_subscr.device);
	if (dev == NULL)
		goto out;

	nb = x25_get_neigh(dev);
	if (nb == NULL)
		goto out_dev_put;

	dev_put(dev);

	if (cmd == SIOCX25GSUBSCRIP) {
		x25_subscr.extended = nb->extended;
		x25_subscr.global_facil_mask = nb->global_facil_mask;
		rc = copy_to_user(x25_subscr32, &x25_subscr,
				sizeof(*x25_subscr32)) ? -EFAULT : 0;
	} else {
		rc = -EINVAL;
		if (x25_subscr.extended == 0 || x25_subscr.extended == 1) {
			rc = 0;
			nb->extended = x25_subscr.extended;
			nb->global_facil_mask = x25_subscr.global_facil_mask;
		}
	}
	x25_neigh_put(nb);
out:
	return rc;
out_dev_put:
	dev_put(dev);
	goto out;
}

static int compat_x25_ioctl(struct socket *sock, unsigned int cmd,
				unsigned long arg)
{
	void __user *argp = compat_ptr(arg);
	struct sock *sk = sock->sk;

	int rc = -ENOIOCTLCMD;

	switch(cmd) {
	case TIOCOUTQ:
	case TIOCINQ:
		rc = x25_ioctl(sock, cmd, (unsigned long)argp);
		break;
	case SIOCGSTAMP:
		rc = -EINVAL;
		if (sk)
			rc = compat_sock_get_timestamp(sk,
					(struct timeval __user*)argp);
		break;
	case SIOCGIFADDR:
	case SIOCSIFADDR:
	case SIOCGIFDSTADDR:
	case SIOCSIFDSTADDR:
	case SIOCGIFBRDADDR:
	case SIOCSIFBRDADDR:
	case SIOCGIFNETMASK:
	case SIOCSIFNETMASK:
	case SIOCGIFMETRIC:
	case SIOCSIFMETRIC:
		rc = -EINVAL;
		break;
	case SIOCADDRT:
	case SIOCDELRT:
		rc = -EPERM;
		if (!capable(CAP_NET_ADMIN))
			break;
		rc = x25_route_ioctl(cmd, argp);
		break;
	case SIOCX25GSUBSCRIP:
		rc = compat_x25_subscr_ioctl(cmd, argp);
		break;
	case SIOCX25SSUBSCRIP:
		rc = -EPERM;
		if (!capable(CAP_NET_ADMIN))
			break;
		rc = compat_x25_subscr_ioctl(cmd, argp);
		break;
	case SIOCX25GFACILITIES:
	case SIOCX25SFACILITIES:
	case SIOCX25GDTEFACILITIES:
	case SIOCX25SDTEFACILITIES:
	case SIOCX25GCALLUSERDATA:
	case SIOCX25SCALLUSERDATA:
	case SIOCX25GCAUSEDIAG:
	case SIOCX25SCUDMATCHLEN:
	case SIOCX25CALLACCPTAPPRV:
	case SIOCX25SENDCALLACCPT:
		rc = x25_ioctl(sock, cmd, (unsigned long)argp);
		break;
	default:
		rc = -ENOIOCTLCMD;
		break;
	}
	return rc;
}
#endif

static const struct proto_ops SOCKOPS_WRAPPED(x25_proto_ops) = {
	.family =	AF_X25,
	.owner =	THIS_MODULE,
	.release =	x25_release,
	.bind =		x25_bind,
	.connect =	x25_connect,
	.socketpair =	sock_no_socketpair,
	.accept =	x25_accept,
	.getname =	x25_getname,
	.poll =		datagram_poll,
	.ioctl =	x25_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = compat_x25_ioctl,
#endif
	.listen =	x25_listen,
	.shutdown =	sock_no_shutdown,
	.setsockopt =	x25_setsockopt,
	.getsockopt =	x25_getsockopt,
	.sendmsg =	x25_sendmsg,
	.recvmsg =	x25_recvmsg,
	.mmap =		sock_no_mmap,
	.sendpage =	sock_no_sendpage,
};

#include <linux/smp_lock.h>
SOCKOPS_WRAP(x25_proto, AF_X25);

static struct packet_type x25_packet_type = {
	.type =	__constant_htons(ETH_P_X25),
	.func =	x25_lapb_receive_frame,
};

static struct notifier_block x25_dev_notifier = {
	.notifier_call = x25_device_event,
};

void x25_kill_by_neigh(struct x25_neigh *nb)
{
	struct sock *s;
	struct hlist_node *node;

	write_lock_bh(&x25_list_lock);

	sk_for_each(s, node, &x25_list)
		if (x25_sk(s)->neighbour == nb)
			x25_disconnect(s, ENETUNREACH, 0, 0);

	write_unlock_bh(&x25_list_lock);
}

static int __init x25_init(void)
{
	int rc = proto_register(&x25_proto, 0);

	if (rc != 0)
		goto out;

	sock_register(&x25_family_ops);

	dev_add_pack(&x25_packet_type);

	register_netdevice_notifier(&x25_dev_notifier);

	printk(KERN_INFO "X.25 for Linux. Version 0.2 for Linux 2.1.15\n");

#ifdef CONFIG_SYSCTL
	x25_register_sysctl();
#endif
	x25_proc_init();
out:
	return rc;
}
module_init(x25_init);

static void __exit x25_exit(void)
{
	x25_proc_exit();
	x25_link_free();
	x25_route_free();

#ifdef CONFIG_SYSCTL
	x25_unregister_sysctl();
#endif

	unregister_netdevice_notifier(&x25_dev_notifier);

	dev_remove_pack(&x25_packet_type);

	sock_unregister(AF_X25);
	proto_unregister(&x25_proto);
}
module_exit(x25_exit);

MODULE_AUTHOR("Jonathan Naylor <[e-mail]>");
MODULE_DESCRIPTION("The X.25 Packet Layer network layer protocol");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_X25);