af_ipx.c

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	if (!intrfc)
		goto out;
	memcpy((char *)&(intrfc->if_node), idef->ipx_node, IPX_NODE_LEN);
	ipx_internal_net = ipx_primary_net = intrfc;
	ipxitf_hold(intrfc);
	ipxitf_insert(intrfc);

	ret = ipxitf_add_local_route(intrfc);
	ipxitf_put(intrfc);
out:	return ret;
}

static int ipx_map_frame_type(unsigned char type)
{
	int ret = 0;

	switch (type) {
		case IPX_FRAME_ETHERII:
			ret = __constant_htons(ETH_P_IPX);
			break;
		case IPX_FRAME_8022:
			ret = __constant_htons(ETH_P_802_2);
			break;
		case IPX_FRAME_SNAP:
			ret = __constant_htons(ETH_P_SNAP);
			break;
		case IPX_FRAME_8023:
			ret = __constant_htons(ETH_P_802_3);
			break;
	}

	return ret;
}

static int ipxitf_create(ipx_interface_definition *idef)
{
	struct net_device *dev;
	unsigned short dlink_type = 0;
	struct datalink_proto *datalink = NULL;
	ipx_interface *intrfc;
	int err;

	if (idef->ipx_special == IPX_INTERNAL) {
		err = ipxitf_create_internal(idef);
		goto out;
	}

	err = -EEXIST;
	if (idef->ipx_special == IPX_PRIMARY && ipx_primary_net)
		goto out;

	intrfc = ipxitf_find_using_net(idef->ipx_network);
	err = -EADDRINUSE;
	if (idef->ipx_network && intrfc) {
		ipxitf_put(intrfc);
		goto out;
	}

	if (intrfc)
		ipxitf_put(intrfc);

	dev = dev_get_by_name(idef->ipx_device);
	err = -ENODEV;
	if (!dev)
		goto out;

	switch (idef->ipx_dlink_type) {
		case IPX_FRAME_TR_8022:
			printk(KERN_WARNING "IPX frame type 802.2TR is "
				"obsolete Use 802.2 instead.\n");
			/* fall through */
		case IPX_FRAME_8022:
			dlink_type 	= __constant_htons(ETH_P_802_2);
			datalink 	= p8022_datalink;
			break;
		case IPX_FRAME_ETHERII:
			if (dev->type != ARPHRD_IEEE802) {
				dlink_type 	= __constant_htons(ETH_P_IPX);
				datalink 	= pEII_datalink;
				break;
			} else 
				printk(KERN_WARNING "IPX frame type EtherII "
					"over token-ring is obsolete. Use SNAP "
					"instead.\n");
			/* fall through */
		case IPX_FRAME_SNAP:
			dlink_type 	= __constant_htons(ETH_P_SNAP);
			datalink 	= pSNAP_datalink;
			break;
		case IPX_FRAME_8023:
			dlink_type 	= __constant_htons(ETH_P_802_3);
			datalink 	= p8023_datalink;
			break;
		case IPX_FRAME_NONE:
		default:
			err = -EPROTONOSUPPORT;
			goto out_dev;
	}

	err = -ENETDOWN;
	if (!(dev->flags & IFF_UP))
		goto out_dev;

	/* Check addresses are suitable */
	err = -EINVAL;
	if (dev->addr_len > IPX_NODE_LEN)
		goto out_dev;

	intrfc = ipxitf_find_using_phys(dev, dlink_type);
	if (!intrfc) {
		/* Ok now create */
		intrfc = ipxitf_alloc(dev, idef->ipx_network, dlink_type,
				      datalink, 0, dev->hard_header_len +
					datalink->header_length);
		err = -EAGAIN;
		if (!intrfc)
			goto out_dev;
		/* Setup primary if necessary */
		if (idef->ipx_special == IPX_PRIMARY)
			ipx_primary_net = intrfc;
		if (!memcmp(idef->ipx_node, "\000\000\000\000\000\000",
			    IPX_NODE_LEN)) {
			memset(intrfc->if_node, 0, IPX_NODE_LEN);
			memcpy(intrfc->if_node + IPX_NODE_LEN - dev->addr_len,
				dev->dev_addr, dev->addr_len);
		} else
			memcpy(intrfc->if_node, idef->ipx_node, IPX_NODE_LEN);
		ipxitf_hold(intrfc);
		ipxitf_insert(intrfc);
	}


	/* If the network number is known, add a route */
	err = 0;
	if (!intrfc->if_netnum)
		goto out_intrfc;

	err = ipxitf_add_local_route(intrfc);
out_intrfc:
	ipxitf_put(intrfc);
	goto out;
out_dev:
	dev_put(dev);
out:	return err;
}

static int ipxitf_delete(ipx_interface_definition *idef)
{
	struct net_device *dev = NULL;
	unsigned short dlink_type = 0;
	ipx_interface *intrfc;
	int ret = 0;

	spin_lock_bh(&ipx_interfaces_lock);
	if (idef->ipx_special == IPX_INTERNAL) {
		if (ipx_internal_net) {
			__ipxitf_put(ipx_internal_net);
			goto out;
		}
		ret = -ENOENT;
		goto out;
	}

	dlink_type = ipx_map_frame_type(idef->ipx_dlink_type);
	ret = -EPROTONOSUPPORT;
	if (!dlink_type)
		goto out;

	dev = __dev_get_by_name(idef->ipx_device);
	ret = -ENODEV;
	if (!dev)
		goto out;

	intrfc = __ipxitf_find_using_phys(dev, dlink_type);
	ret = -EINVAL;
	if (!intrfc)
		goto out;
	__ipxitf_put(intrfc);

	ret = 0;
out:	spin_unlock_bh(&ipx_interfaces_lock);
	return ret;
}

static ipx_interface *ipxitf_auto_create(struct net_device *dev, 
					 unsigned short dlink_type)
{
	ipx_interface *intrfc = NULL;
	struct datalink_proto *datalink;

	if (!dev)
		goto out;

	/* Check addresses are suitable */
	if (dev->addr_len > IPX_NODE_LEN)
		goto out;

	switch (htons(dlink_type)) {
		case ETH_P_IPX:
			datalink = pEII_datalink;
			break;

		case ETH_P_802_2:
			datalink = p8022_datalink;
			break;

		case ETH_P_SNAP:
			datalink = pSNAP_datalink;
			break;

		case ETH_P_802_3:
			datalink = p8023_datalink;
			break;

		default:
			goto out;
	}

	intrfc = ipxitf_alloc(dev, 0, dlink_type, datalink, 0,
				dev->hard_header_len + datalink->header_length);

	if (intrfc) {
		memset(intrfc->if_node, 0, IPX_NODE_LEN);
		memcpy((char *)&(intrfc->if_node[IPX_NODE_LEN-dev->addr_len]),
			dev->dev_addr, dev->addr_len);
		spin_lock_init(&intrfc->if_sklist_lock);
		atomic_set(&intrfc->refcnt, 1);
		ipxitf_insert(intrfc);
		dev_hold(dev);
	}

out:	return intrfc;
}

static int ipxitf_ioctl(unsigned int cmd, void *arg)
{
	struct ifreq ifr;
	int val;

	switch (cmd) {
		case SIOCSIFADDR: {
			struct sockaddr_ipx *sipx;
			ipx_interface_definition f;

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

			sipx = (struct sockaddr_ipx *)&ifr.ifr_addr;
			if (sipx->sipx_family != AF_IPX)
				return -EINVAL;

			f.ipx_network = sipx->sipx_network;
			memcpy(f.ipx_device, ifr.ifr_name,
				sizeof(f.ipx_device));
			memcpy(f.ipx_node, sipx->sipx_node, IPX_NODE_LEN);
			f.ipx_dlink_type = sipx->sipx_type;
			f.ipx_special = sipx->sipx_special;

			if (sipx->sipx_action == IPX_DLTITF)
				return ipxitf_delete(&f);
			else
				return ipxitf_create(&f);
		}

		case SIOCGIFADDR: {
			int err = 0;
			struct sockaddr_ipx *sipx;
			ipx_interface *ipxif;
			struct net_device *dev;

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

			sipx = (struct sockaddr_ipx *)&ifr.ifr_addr;
			dev = __dev_get_by_name(ifr.ifr_name);
			if (!dev)
				return -ENODEV;

			ipxif = ipxitf_find_using_phys(dev, ipx_map_frame_type(sipx->sipx_type));
			if (!ipxif)
				return -EADDRNOTAVAIL;

			sipx->sipx_family	= AF_IPX;
			sipx->sipx_network	= ipxif->if_netnum;
			memcpy(sipx->sipx_node, ipxif->if_node,
				sizeof(sipx->sipx_node));
			if (copy_to_user(arg, &ifr, sizeof(ifr)))
				err = -EFAULT;

			ipxitf_put(ipxif);
			return err;
		}

		case SIOCAIPXITFCRT: 
			if (get_user(val, (unsigned char *) arg))
				return -EFAULT;
			ipxcfg_set_auto_create(val);
			break;

		case SIOCAIPXPRISLT: 
			if (get_user(val, (unsigned char *) arg))
				return -EFAULT;
			ipxcfg_set_auto_select(val);
			break;

		default:
			return -EINVAL;
	}

	return 0;
}

/* Routing tables for the IPX socket layer. */

static inline void ipxrtr_hold(ipx_route *rt)
{
	atomic_inc(&rt->refcnt);
}

static inline void ipxrtr_put(ipx_route *rt)
{
	if (atomic_dec_and_test(&rt->refcnt))
		kfree(rt);
}

static ipx_route *ipxrtr_lookup(__u32 net)
{
	ipx_route *r;

	read_lock_bh(&ipx_routes_lock);
	for (r = ipx_routes; r && r->ir_net != net; r = r->ir_next)
		;
	if (r)
		ipxrtr_hold(r);
	read_unlock_bh(&ipx_routes_lock);

	return r;
}

/* caller must hold a reference to intrfc */

static int ipxrtr_add_route(__u32 network, ipx_interface *intrfc,
				unsigned char *node)
{
	ipx_route *rt;
	int ret;

	/* Get a route structure; either existing or create */
	rt = ipxrtr_lookup(network);
	if (!rt) {
		rt = kmalloc(sizeof(ipx_route), GFP_ATOMIC);
		ret = -EAGAIN;
		if (!rt)
			goto out;

		atomic_set(&rt->refcnt, 1);
		ipxrtr_hold(rt);
		write_lock_bh(&ipx_routes_lock);
		rt->ir_next	= ipx_routes;
		ipx_routes	= rt;
		write_unlock_bh(&ipx_routes_lock);
	} else {
		ret = -EEXIST;
		if (intrfc == ipx_internal_net)
			goto out_put;
	}

	rt->ir_net 	= network;
	rt->ir_intrfc 	= intrfc;
	if (!node) {
		memset(rt->ir_router_node, '\0', IPX_NODE_LEN);
		rt->ir_routed = 0;
	} else {
		memcpy(rt->ir_router_node, node, IPX_NODE_LEN);
		rt->ir_routed = 1;
	}

	ret = 0;
out_put:
	ipxrtr_put(rt);
out:	return ret;
}

static void ipxrtr_del_routes(ipx_interface *intrfc)
{
	ipx_route **r, *tmp;

	write_lock_bh(&ipx_routes_lock);
	for (r = &ipx_routes; (tmp = *r) != NULL;) {
		if (tmp->ir_intrfc == intrfc) {
			*r = tmp->ir_next;
			ipxrtr_put(tmp);
		} else
			r = &(tmp->ir_next);
	}
	write_unlock_bh(&ipx_routes_lock);
}

static int ipxrtr_create(ipx_route_definition *rd)
{
	ipx_interface *intrfc;
	int ret = -ENETUNREACH;

	/* Find the appropriate interface */
	intrfc = ipxitf_find_using_net(rd->ipx_router_network);
	if (!intrfc)
		goto out;
	ret = ipxrtr_add_route(rd->ipx_network, intrfc, rd->ipx_router_node);
	ipxitf_put(intrfc);
out:	return ret;
}

static int ipxrtr_delete(long net)
{
	ipx_route **r;
	ipx_route *tmp;
	int err;

	write_lock_bh(&ipx_routes_lock);
	for (r = &ipx_routes; (tmp = *r) != NULL;) {
		if (tmp->ir_net == net) {
			/* Directly connected; can't lose route */
			err = -EPERM;
			if (!tmp->ir_routed)
				goto out;

			*r = tmp->ir_next;
			ipxrtr_put(tmp);
			err = 0;
			goto out;
		}

		r = &(tmp->ir_next);
	}
	err = -ENOENT;
out:	write_unlock_bh(&ipx_routes_lock);
	return err;
}

/*
 *	Checksum routine for IPX
 */
 
/* Note: We assume ipx_tctrl==0 and htons(length)==ipx_pktsize */
/* This functions should *not* mess with packet contents */

static __u16 ipx_cksum(struct ipxhdr *packet, int length) 
{
	/* 
	 *	NOTE: sum is a net byte order quantity, which optimizes the 
	 *	loop. This only works on big and little endian machines. (I
	 *	don't know of a machine that isn't.)
	 */
	/* start at ipx_dest - We skip the checksum field and start with
	 * ipx_type before the loop, not considering ipx_tctrl in the calc */
	__u16 *p = (__u16 *)&packet->ipx_dest;
	__u32 i = (length >> 1) - 1; /* Number of complete words */
	__u32 sum = packet->ipx_type << sizeof(packet->ipx_tctrl); 

	/* Loop through all complete words except the checksum field,
	 * ipx_type (accounted above) and ipx_tctrl (not used in the cksum) */
	while (--i)
		sum += *p++;

	/* Add on the last part word if it exists */
	if (packet->ipx_pktsize & __constant_htons(1))
		sum += ntohs(0xff00) & *p;

	/* Do final fixup */
	sum = (sum & 0xffff) + (sum >> 16);

	/* It's a pity there's no concept of carry in C */
	if (sum >= 0x10000)
		sum++;

	return ~sum;
}

/*
 * Route an outgoing frame from a socket.
 */
static int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,
				struct iovec *iov, int len, int noblock)
{
	struct sk_buff *skb;
	ipx_interface *intrfc;
	struct ipxhdr *ipx;
	int size;
	int ipx_offset;
	ipx_route *rt = NULL;
	int err;

	/* Find the appropriate interface on which to send packet */
	if (!usipx->sipx_network && ipx_primary_net) {
		usipx->sipx_network = ipx_primary_net->if_netnum;
		intrfc = ipx_primary_net;
	} else {
		rt = ipxrtr_lookup(usipx->sipx_network);
		err = -ENETUNREACH;
		if (!rt)
			goto out;
		intrfc = rt->ir_intrfc;
	}

	ipxitf_hold(intrfc);
	ipx_offset = intrfc->if_ipx_offset;
	size = sizeof(struct ipxhdr) + len + ipx_offset;

	skb = sock_alloc_send_skb(sk, size, noblock, &err);
	if (!skb)
		goto out_put;

	skb_reserve(skb, ipx_offset);