af_netrom.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

		if ((dev = nr_dev_first()) == NULL)
			return -ENETUNREACH;

		source = (ax25_address *)dev->dev_addr;

		if ((user = ax25_findbyuid(current->euid)) == NULL) {
			if (ax25_uid_policy && !capable(CAP_NET_ADMIN))
				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);		/* Finish the bind */
	}

	sk->protinfo.nr->dest_addr = addr->sax25_call;

	circuit = nr_find_next_circuit();

	sk->protinfo.nr->my_index = circuit / 256;
	sk->protinfo.nr->my_id    = circuit % 256;

	circuit++;

	/* Move to connecting socket, start sending Connect Requests */
	sock->state            = SS_CONNECTING;
	sk->state              = TCP_SYN_SENT;

	nr_establish_data_link(sk);

	sk->protinfo.nr->state = NR_STATE_1;

	nr_start_heartbeat(sk);

	/* Now the loop */
	if (sk->state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
		return -EINPROGRESS;
		
	cli();	/* To avoid races on the sleep */

	/*
	 * A Connect Ack with Choke or timeout or failed routing will go to closed.
	 */
	while (sk->state == TCP_SYN_SENT) {
		interruptible_sleep_on(sk->sleep);
		if (signal_pending(current)) {
			sti();
			return -ERESTARTSYS;
		}
	}

	if (sk->state != TCP_ESTABLISHED) {
		sti();
		sock->state = SS_UNCONNECTED;
		return sock_error(sk);	/* Always set at this point */
	}

	sock->state = SS_CONNECTED;

	sti();

	return 0;
}

static int nr_accept(struct socket *sock, struct socket *newsock, int flags)
{
	struct sock *sk;
	struct sock *newsk;
	struct sk_buff *skb;

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

	if (sk->type != SOCK_SEQPACKET)
		return -EOPNOTSUPP;

	if (sk->state != TCP_LISTEN)
		return -EINVAL;

	/*
	 *	The write queue this time is holding sockets ready to use
	 *	hooked into the SABM we saved
	 */
	do {
		cli();
		if ((skb = skb_dequeue(&sk->receive_queue)) == NULL) {
			if (flags & O_NONBLOCK) {
				sti();
				return -EWOULDBLOCK;
			}
			interruptible_sleep_on(sk->sleep);
			if (signal_pending(current)) {
				sti();
				return -ERESTARTSYS;
			}
		}
	} while (skb == NULL);

	newsk = skb->sk;
	newsk->pair = NULL;
	newsk->socket = newsock;
	newsk->sleep = &newsock->wait;
	sti();

	/* Now attach up the new socket */
	kfree_skb(skb);
	sk->ack_backlog--;
	newsock->sk = newsk;

	return 0;
}

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;

	if (peer != 0) {
		if (sk->state != TCP_ESTABLISHED)
			return -ENOTCONN;
		sax->fsa_ax25.sax25_family = AF_NETROM;
		sax->fsa_ax25.sax25_ndigis = 1;
		sax->fsa_ax25.sax25_call   = sk->protinfo.nr->user_addr;
		sax->fsa_digipeater[0]     = sk->protinfo.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   = sk->protinfo.nr->source_addr;
		*uaddr_len = sizeof(struct sockaddr_ax25);
	}

	return 0;
}

int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
{
	struct sock *sk;
	struct sock *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;

	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;

#ifdef CONFIG_INET
	/*
	 * 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->h.raw = skb->data;

		return nr_rx_ip(skb, dev);
	}
#endif

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

		if (frametype == NR_CONNACK && skb->len == 22)
			sk->protinfo.nr->bpqext = 1;
		else
			sk->protinfo.nr->bpqext = 0;

		return nr_process_rx_frame(sk, skb);
	}

	/*
	 * 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. The following hack would
		 * have been a way to extend the protocol but apparently
		 * it kills BPQ boxes... :-(
		 */
#if 0
		/*
		 * Never reply to a CONNACK/CHOKE.
		 */
		if (frametype != NR_CONNACK || flags != NR_CHOKE_FLAG)
			nr_transmit_refusal(skb, 1);
#endif
		return 0;
	}

	sk = nr_find_listener(dest);

	user = (ax25_address *)(skb->data + 21);

	if (sk == NULL || sk->ack_backlog == sk->max_ack_backlog || (make = nr_make_new(sk)) == NULL) {
		nr_transmit_refusal(skb, 0);
		return 0;
	}

	window = skb->data[20];

	skb->sk             = make;
	make->state         = TCP_ESTABLISHED;

	/* Fill in his circuit details */
	make->protinfo.nr->source_addr = *dest;
	make->protinfo.nr->dest_addr   = *src;
	make->protinfo.nr->user_addr   = *user;

	make->protinfo.nr->your_index  = circuit_index;
	make->protinfo.nr->your_id     = circuit_id;

	circuit = nr_find_next_circuit();

	make->protinfo.nr->my_index    = circuit / 256;
	make->protinfo.nr->my_id       = circuit % 256;

	circuit++;

	/* Window negotiation */
	if (window < make->protinfo.nr->window)
		make->protinfo.nr->window = window;

	/* L4 timeout negotiation */
	if (skb->len == 37) {
		timeout = skb->data[36] * 256 + skb->data[35];
		if (timeout * HZ < make->protinfo.nr->t1)
			make->protinfo.nr->t1 = timeout * HZ;
		make->protinfo.nr->bpqext = 1;
	} else {
		make->protinfo.nr->bpqext = 0;
	}

	nr_write_internal(make, NR_CONNACK);

	make->protinfo.nr->condition = 0x00;
	make->protinfo.nr->vs        = 0;
	make->protinfo.nr->va        = 0;
	make->protinfo.nr->vr        = 0;
	make->protinfo.nr->vl        = 0;
	make->protinfo.nr->state     = NR_STATE_3;
	sk->ack_backlog++;
	make->pair = sk;

	nr_insert_socket(make);

	skb_queue_head(&sk->receive_queue, skb);

	nr_start_heartbeat(make);
	nr_start_idletimer(make);

	if (!sk->dead)
		sk->data_ready(sk, skb->len);

	return 1;
}

static int nr_sendmsg(struct socket *sock, struct msghdr *msg, int len, struct scm_cookie *scm)
{
	struct sock *sk = sock->sk;
	struct sockaddr_ax25 *usax = (struct sockaddr_ax25 *)msg->msg_name;
	int err;
	struct sockaddr_ax25 sax;
	struct sk_buff *skb;
	unsigned char *asmptr;
	int size;

	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR))
		return -EINVAL;

	if (sk->zapped)
		return -EADDRNOTAVAIL;

	if (sk->shutdown & SEND_SHUTDOWN) {
		send_sig(SIGPIPE, current, 0);
		return -EPIPE;
	}

	if (sk->protinfo.nr->device == NULL)
		return -ENETUNREACH;

	if (usax) {
		if (msg->msg_namelen < sizeof(sax))
			return -EINVAL;
		sax = *usax;
		if (ax25cmp(&sk->protinfo.nr->dest_addr, &sax.sax25_call) != 0)
			return -EISCONN;
		if (sax.sax25_family != AF_NETROM)
			return -EINVAL;
	} else {
		if (sk->state != TCP_ESTABLISHED)
			return -ENOTCONN;
		sax.sax25_family = AF_NETROM;
		sax.sax25_call   = sk->protinfo.nr->dest_addr;
	}

	SOCK_DEBUG(sk, "NET/ROM: sendto: Addresses built.\n");

	/* Build a packet */
	SOCK_DEBUG(sk, "NET/ROM: sendto: building packet.\n");
	size = len + AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + NR_NETWORK_LEN + NR_TRANSPORT_LEN;

	if ((skb = sock_alloc_send_skb(sk, size, 0, msg->msg_flags & MSG_DONTWAIT, &err)) == NULL)
		return err;

	skb_reserve(skb, size - len);

	/*
	 *	Push down the NET/ROM header
	 */

	asmptr = skb_push(skb, NR_TRANSPORT_LEN);
	SOCK_DEBUG(sk, "Building NET/ROM Header.\n");

	/* Build a NET/ROM Transport header */

	*asmptr++ = sk->protinfo.nr->your_index;
	*asmptr++ = sk->protinfo.nr->your_id;
	*asmptr++ = 0;		/* To be filled in later */
	*asmptr++ = 0;		/*      Ditto            */
	*asmptr++ = NR_INFO;
	SOCK_DEBUG(sk, "Built header.\n");

	/*
	 *	Put the data on the end
	 */

	skb->h.raw = skb_put(skb, len);

	asmptr = skb->h.raw;
	SOCK_DEBUG(sk, "NET/ROM: Appending user data\n");

	/* User data follows immediately after the NET/ROM transport header */
	memcpy_fromiovec(asmptr, msg->msg_iov, len);
	SOCK_DEBUG(sk, "NET/ROM: Transmitting buffer\n");

	if (sk->state != TCP_ESTABLISHED) {
		kfree_skb(skb);
		return -ENOTCONN;
	}

	nr_output(sk, skb);	/* Shove it onto the queue */

	return len;
}

static int nr_recvmsg(struct socket *sock, struct msghdr *msg, int size, 
	int flags, struct scm_cookie *scm)
{
	struct sock *sk = sock->sk;
	struct sockaddr_ax25 *sax = (struct sockaddr_ax25 *)msg->msg_name;
	int copied;
	struct sk_buff *skb;
	int er;

	/*
	 * This works for seqpacket too. The receiver has ordered the queue for
	 * us! We do one quick check first though
	 */

	if (sk->state != TCP_ESTABLISHED)
		return -ENOTCONN;

	/* Now we can treat all alike */
	if ((skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &er)) == NULL)
		return er;

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

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

	skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);

	if (sax != NULL) {
		sax->sax25_family = AF_NETROM;
		memcpy(sax->sax25_call.ax25_call, skb->data + 7, AX25_ADDR_LEN);
	}

	msg->msg_namelen = sizeof(*sax);

	skb_free_datagram(sk, skb);

	return copied;
}


static int nr_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct sock *sk = sock->sk;

	switch (cmd) {
		case TIOCOUTQ: {
			long amount;
			amount = sk->sndbuf - atomic_read(&sk->wmem_alloc);
			if (amount < 0)
				amount = 0;
			return put_user(amount, (int *)arg);
		}

		case TIOCINQ: {
			struct sk_buff *skb;
			long amount = 0L;
			/* These two are safe on a single CPU system as only user tasks fiddle here */
			if ((skb = skb_peek(&sk->receive_queue)) != NULL)
				amount = skb->len;
			return put_user(amount, (int *)arg);
		}

		case SIOCGSTAMP:
			if (sk != NULL) {
				if (sk->stamp.tv_sec == 0)
					return -ENOENT;
				return copy_to_user((void *)arg, &sk->stamp, sizeof(struct timeval)) ? -EFAULT : 0;
			}
			return -EINVAL;

		case SIOCGIFADDR:
		case SIOCSIFADDR:
		case SIOCGIFDSTADDR:
		case SIOCSIFDSTADDR:
		case SIOCGIFBRDADDR:
		case SIOCSIFBRDADDR:
		case SIOCGIFNETMASK:
		case SIOCSIFNETMASK:
		case SIOCGIFMETRIC:
		case SIOCSIFMETRIC:
			return -EINVAL;

		case SIOCADDRT:
		case SIOCDELRT:
		case SIOCNRDECOBS:
			if (!capable(CAP_NET_ADMIN)) return -EPERM;
			return nr_rt_ioctl(cmd, (void *)arg);

 		default:
			return dev_ioctl(cmd, (void *)arg);
	}

	/*NOTREACHED*/
	return 0;
}

static int nr_get_info(char *buffer, char **start, off_t offset, int length)
{
	struct sock *s;
	struct net_device *dev;
	const char *devname;
	int len = 0;
	off_t pos = 0;
	off_t begin = 0;

	cli();

	len += sprintf(buffer, "user_addr dest_node src_node  dev    my  your  st  vs  vr  va    t1     t2     t4      idle   n2  wnd Snd-Q Rcv-Q inode\n");

	for (s = nr_list; s != NULL; s = s->next) {
		if ((dev = s->protinfo.nr->device) == NULL)
			devname = "???";
		else
			devname = dev->name;

		len += sprintf(buffer + len, "%-9s ",
			ax2asc(&s->protinfo.nr->user_addr));
		len += sprintf(buffer + len, "%-9s ",
			ax2asc(&s->protinfo.nr->dest_addr));
		len += sprintf(buffer + len, "%-9s %-3s  %02X/%02X %02X/%02X %2d %3d %3d %3d %3lu/%03lu %2lu/%02lu %3lu/%03lu %3lu/%03lu %2d/%02d %3d %5d %5d %ld\n",
			ax2asc(&s->protinfo.nr->source_addr),
			devname,
			s->protinfo.nr->my_index,
			s->protinfo.nr->my_id,
			s->protinfo.nr->your_index,
			s->protinfo.nr->your_id,
			s->protinfo.nr->state,
			s->protinfo.nr->vs,
			s->protinfo.nr->vr,
			s->protinfo.nr->va,
			ax25_display_timer(&s->protinfo.nr->t1timer) / HZ,
			s->protinfo.nr->t1 / HZ,
			ax25_display_timer(&s->protinfo.nr->t2timer) / HZ,
			s->protinfo.nr->t2 / HZ,
			ax25_display_timer(&s->protinfo.nr->t4timer) / HZ,
			s->protinfo.nr->t4 / HZ,
			ax25_display_timer(&s->protinfo.nr->idletimer) / (60 * HZ),
			s->protinfo.nr->idle / (60 * HZ),
			s->protinfo.nr->n2count,
			s->protinfo.nr->n2,
			s->protinfo.nr->window,
			atomic_read(&s->wmem_alloc),
			atomic_read(&s->rmem_alloc),
			s->socket != NULL ? s->socket->inode->i_ino : 0L);

		pos = begin + len;

		if (pos < offset) {
			len   = 0;
			begin = pos;
		}

		if (pos > offset + length)
			break;
	}

	sti();

	*start = buffer + (offset - begin);
	len   -= (offset - begin);

	if (len > length) len = length;

	return(len);
} 

static struct net_proto_family nr_family_ops = 
{
	PF_NETROM,
	nr_create
};

static struct proto_ops SOCKOPS_WRAPPED(nr_proto_ops) = {
	family:		PF_NETROM,

	release:	nr_release,
	bind:		nr_bind,
	connect:	nr_connect,
	socketpair:	sock_no_socketpair,
	accept:		nr_accept,
	getname:	nr_getname,
	poll:		datagram_poll,
	ioctl:		nr_ioctl,
	listen:		nr_listen,
	shutdown:	sock_no_shutdown,
	setsockopt:	nr_setsockopt,
	getsockopt:	nr_getsockopt,
	sendmsg:	nr_sendmsg,
	recvmsg:	nr_recvmsg,
	mmap:		sock_no_mmap,
};

#include <linux/smp_lock.h>
SOCKOPS_WRAP(nr_proto, PF_NETROM);

static struct notifier_block nr_dev_notifier = {
	nr_device_event,
	0
};

static struct net_device *dev_nr;

static int __init nr_proto_init(void)
{
	int i;

	if ((dev_nr = kmalloc(nr_ndevs * sizeof(struct net_device), GFP_KERNEL)) == NULL) {
		printk(KERN_ERR "NET/ROM: nr_proto_init - unable to allocate device structure\n");
		return -1;
	}

	memset(dev_nr, 0x00, nr_ndevs * sizeof(struct net_device));

	for (i = 0; i < nr_ndevs; i++) {
		sprintf(dev_nr[i].name, "nr%d", i);
		dev_nr[i].init = nr_init;
		register_netdev(&dev_nr[i]);
	}

	sock_register(&nr_family_ops);
	register_netdevice_notifier(&nr_dev_notifier);
	printk(KERN_INFO "G4KLX NET/ROM for Linux. Version 0.7 for AX25.037 Linux 2.4\n");

	ax25_protocol_register(AX25_P_NETROM, nr_route_frame);
	ax25_linkfail_register(nr_link_failed);

#ifdef CONFIG_SYSCTL
	nr_register_sysctl();
#endif

	nr_loopback_init();

	proc_net_create("nr", 0, nr_get_info);
	proc_net_create("nr_neigh", 0, nr_neigh_get_info);
	proc_net_create("nr_nodes", 0, nr_nodes_get_info);
	return 0;
}

module_init(nr_proto_init);


EXPORT_NO_SYMBOLS;

MODULE_PARM(nr_ndevs, "i");
MODULE_PARM_DESC(nr_ndevs, "number of NET/ROM devices");

MODULE_AUTHOR("Jonathan Naylor G4KLX <[e-mail]>");
MODULE_DESCRIPTION("The amateur radio NET/ROM network and transport layer protocol");

static void __exit nr_exit(void)
{
	int i;

	proc_net_remove("nr");
	proc_net_remove("nr_neigh");
	proc_net_remove("nr_nodes");
	nr_loopback_clear();

	nr_rt_free();

	ax25_protocol_release(AX25_P_NETROM);
	ax25_linkfail_release(nr_link_failed);

	unregister_netdevice_notifier(&nr_dev_notifier);

#ifdef CONFIG_SYSCTL
	nr_unregister_sysctl();
#endif
	sock_unregister(PF_NETROM);

	for (i = 0; i < nr_ndevs; i++) {
		if (dev_nr[i].priv != NULL) {
			kfree(dev_nr[i].priv);
			dev_nr[i].priv = NULL;
			unregister_netdev(&dev_nr[i]);
		}
		kfree(dev_nr[i].name);
	}

	kfree(dev_nr);
}
module_exit(nr_exit);