af_ipx.c

linux 内核源代码

	if (copy)
		skb1 = skb_clone(skb, GFP_ATOMIC);
	else
		skb1 = skb;

	rc = -ENOMEM;
	if (!skb1)
		goto out_put;

	/* Do we need 2 SKBs? */
	if (sock1 && sock2)
		skb2 = skb_clone(skb1, GFP_ATOMIC);
	else
		skb2 = skb1;

	if (sock1)
		ipxitf_def_skb_handler(sock1, skb1);

	if (!skb2)
		goto out_put;

	if (sock2)
		ipxitf_def_skb_handler(sock2, skb2);

	rc = 0;
out_put:
	if (sock1)
		sock_put(sock1);
	if (sock2)
		sock_put(sock2);
out:
	return rc;
}
#endif	/* CONFIG_IPX_INTERN */

static struct sk_buff *ipxitf_adjust_skbuff(struct ipx_interface *intrfc,
					    struct sk_buff *skb)
{
	struct sk_buff *skb2;
	int in_offset = (unsigned char *)ipx_hdr(skb) - skb->head;
	int out_offset = intrfc->if_ipx_offset;
	int len;

	/* Hopefully, most cases */
	if (in_offset >= out_offset)
		return skb;

	/* Need new SKB */
	len  = skb->len + out_offset;
	skb2 = alloc_skb(len, GFP_ATOMIC);
	if (skb2) {
		skb_reserve(skb2, out_offset);
		skb_reset_network_header(skb2);
		skb_reset_transport_header(skb2);
		skb_put(skb2, skb->len);
		memcpy(ipx_hdr(skb2), ipx_hdr(skb), skb->len);
		memcpy(skb2->cb, skb->cb, sizeof(skb->cb));
	}
	kfree_skb(skb);
	return skb2;
}

/* caller must hold a reference to intrfc and the skb has to be unshared */
int ipxitf_send(struct ipx_interface *intrfc, struct sk_buff *skb, char *node)
{
	struct ipxhdr *ipx = ipx_hdr(skb);
	struct net_device *dev = intrfc->if_dev;
	struct datalink_proto *dl = intrfc->if_dlink;
	char dest_node[IPX_NODE_LEN];
	int send_to_wire = 1;
	int addr_len;

	ipx->ipx_tctrl = IPX_SKB_CB(skb)->ipx_tctrl;
	ipx->ipx_dest.net = IPX_SKB_CB(skb)->ipx_dest_net;
	ipx->ipx_source.net = IPX_SKB_CB(skb)->ipx_source_net;

	/* see if we need to include the netnum in the route list */
	if (IPX_SKB_CB(skb)->last_hop.index >= 0) {
		__be32 *last_hop = (__be32 *)(((u8 *) skb->data) +
				sizeof(struct ipxhdr) +
				IPX_SKB_CB(skb)->last_hop.index *
				sizeof(__be32));
		*last_hop = IPX_SKB_CB(skb)->last_hop.netnum;
		IPX_SKB_CB(skb)->last_hop.index = -1;
	}

	/*
	 * We need to know how many skbuffs it will take to send out this
	 * packet to avoid unnecessary copies.
	 */

	if (!dl || !dev || dev->flags & IFF_LOOPBACK)
		send_to_wire = 0;	/* No non looped */

	/*
	 * See if this should be demuxed to sockets on this interface
	 *
	 * We want to ensure the original was eaten or that we only use
	 * up clones.
	 */

	if (ipx->ipx_dest.net == intrfc->if_netnum) {
		/*
		 * To our own node, loop and free the original.
		 * The internal net will receive on all node address.
		 */
		if (intrfc == ipx_internal_net ||
		    !memcmp(intrfc->if_node, node, IPX_NODE_LEN)) {
			/* Don't charge sender */
			skb_orphan(skb);

			/* Will charge receiver */
			return ipxitf_demux_socket(intrfc, skb, 0);
		}

		/* Broadcast, loop and possibly keep to send on. */
		if (!memcmp(ipx_broadcast_node, node, IPX_NODE_LEN)) {
			if (!send_to_wire)
				skb_orphan(skb);
			ipxitf_demux_socket(intrfc, skb, send_to_wire);
			if (!send_to_wire)
				goto out;
		}
	}

	/*
	 * If the originating net is not equal to our net; this is routed
	 * We are still charging the sender. Which is right - the driver
	 * free will handle this fairly.
	 */
	if (ipx->ipx_source.net != intrfc->if_netnum) {
		/*
		 * Unshare the buffer before modifying the count in
		 * case it's a flood or tcpdump
		 */
		skb = skb_unshare(skb, GFP_ATOMIC);
		if (!skb)
			goto out;
		if (++ipx->ipx_tctrl > ipxcfg_max_hops)
			send_to_wire = 0;
	}

	if (!send_to_wire) {
		kfree_skb(skb);
		goto out;
	}

	/* Determine the appropriate hardware address */
	addr_len = dev->addr_len;
	if (!memcmp(ipx_broadcast_node, node, IPX_NODE_LEN))
		memcpy(dest_node, dev->broadcast, addr_len);
	else
		memcpy(dest_node, &(node[IPX_NODE_LEN-addr_len]), addr_len);

	/* Make any compensation for differing physical/data link size */
	skb = ipxitf_adjust_skbuff(intrfc, skb);
	if (!skb)
		goto out;

	/* set up data link and physical headers */
	skb->dev	= dev;
	skb->protocol	= htons(ETH_P_IPX);

	/* Send it out */
	dl->request(dl, skb, dest_node);
out:
	return 0;
}

static int ipxitf_add_local_route(struct ipx_interface *intrfc)
{
	return ipxrtr_add_route(intrfc->if_netnum, intrfc, NULL);
}

static void ipxitf_discover_netnum(struct ipx_interface *intrfc,
				   struct sk_buff *skb);
static int ipxitf_pprop(struct ipx_interface *intrfc, struct sk_buff *skb);

static int ipxitf_rcv(struct ipx_interface *intrfc, struct sk_buff *skb)
{
	struct ipxhdr *ipx = ipx_hdr(skb);
	int rc = 0;

	ipxitf_hold(intrfc);

	/* See if we should update our network number */
	if (!intrfc->if_netnum) /* net number of intrfc not known yet */
		ipxitf_discover_netnum(intrfc, skb);

	IPX_SKB_CB(skb)->last_hop.index = -1;
	if (ipx->ipx_type == IPX_TYPE_PPROP) {
		rc = ipxitf_pprop(intrfc, skb);
		if (rc)
			goto out_free_skb;
	}

	/* local processing follows */
	if (!IPX_SKB_CB(skb)->ipx_dest_net)
		IPX_SKB_CB(skb)->ipx_dest_net = intrfc->if_netnum;
	if (!IPX_SKB_CB(skb)->ipx_source_net)
		IPX_SKB_CB(skb)->ipx_source_net = intrfc->if_netnum;

	/* it doesn't make sense to route a pprop packet, there's no meaning
	 * in the ipx_dest_net for such packets */
	if (ipx->ipx_type != IPX_TYPE_PPROP &&
	    intrfc->if_netnum != IPX_SKB_CB(skb)->ipx_dest_net) {
		/* We only route point-to-point packets. */
		if (skb->pkt_type == PACKET_HOST) {
			skb = skb_unshare(skb, GFP_ATOMIC);
			if (skb)
				rc = ipxrtr_route_skb(skb);
			goto out_intrfc;
		}

		goto out_free_skb;
	}

	/* see if we should keep it */
	if (!memcmp(ipx_broadcast_node, ipx->ipx_dest.node, IPX_NODE_LEN) ||
	    !memcmp(intrfc->if_node, ipx->ipx_dest.node, IPX_NODE_LEN)) {
		rc = ipxitf_demux_socket(intrfc, skb, 0);
		goto out_intrfc;
	}

	/* we couldn't pawn it off so unload it */
out_free_skb:
	kfree_skb(skb);
out_intrfc:
	ipxitf_put(intrfc);
	return rc;
}

static void ipxitf_discover_netnum(struct ipx_interface *intrfc,
				   struct sk_buff *skb)
{
	const struct ipx_cb *cb = IPX_SKB_CB(skb);

	/* see if this is an intra packet: source_net == dest_net */
	if (cb->ipx_source_net == cb->ipx_dest_net && cb->ipx_source_net) {
		struct ipx_interface *i =
				ipxitf_find_using_net(cb->ipx_source_net);
		/* NB: NetWare servers lie about their hop count so we
		 * dropped the test based on it. This is the best way
		 * to determine this is a 0 hop count packet. */
		if (!i) {
			intrfc->if_netnum = cb->ipx_source_net;
			ipxitf_add_local_route(intrfc);
		} else {
			printk(KERN_WARNING "IPX: Network number collision "
				"%lx\n        %s %s and %s %s\n",
				(unsigned long) ntohl(cb->ipx_source_net),
				ipx_device_name(i),
				ipx_frame_name(i->if_dlink_type),
				ipx_device_name(intrfc),
				ipx_frame_name(intrfc->if_dlink_type));
			ipxitf_put(i);
		}
	}
}

/**
 * ipxitf_pprop - Process packet propagation IPX packet type 0x14, used for
 * 		  NetBIOS broadcasts
 * @intrfc: IPX interface receiving this packet
 * @skb: Received packet
 *
 * Checks if packet is valid: if its more than %IPX_MAX_PPROP_HOPS hops or if it
 * is smaller than a IPX header + the room for %IPX_MAX_PPROP_HOPS hops we drop
 * it, not even processing it locally, if it has exact %IPX_MAX_PPROP_HOPS we
 * don't broadcast it, but process it locally. See chapter 5 of Novell's "IPX
 * RIP and SAP Router Specification", Part Number 107-000029-001.
 *
 * If it is valid, check if we have pprop broadcasting enabled by the user,
 * if not, just return zero for local processing.
 *
 * If it is enabled check the packet and don't broadcast it if we have already
 * seen this packet.
 *
 * Broadcast: send it to the interfaces that aren't on the packet visited nets
 * array, just after the IPX header.
 *
 * Returns -EINVAL for invalid packets, so that the calling function drops
 * the packet without local processing. 0 if packet is to be locally processed.
 */
static int ipxitf_pprop(struct ipx_interface *intrfc, struct sk_buff *skb)
{
	struct ipxhdr *ipx = ipx_hdr(skb);
	int i, rc = -EINVAL;
	struct ipx_interface *ifcs;
	char *c;
	__be32 *l;

	/* Illegal packet - too many hops or too short */
	/* We decide to throw it away: no broadcasting, no local processing.
	 * NetBIOS unaware implementations route them as normal packets -
	 * tctrl <= 15, any data payload... */
	if (IPX_SKB_CB(skb)->ipx_tctrl > IPX_MAX_PPROP_HOPS ||
	    ntohs(ipx->ipx_pktsize) < sizeof(struct ipxhdr) +
					IPX_MAX_PPROP_HOPS * sizeof(u32))
		goto out;
	/* are we broadcasting this damn thing? */
	rc = 0;
	if (!sysctl_ipx_pprop_broadcasting)
		goto out;
	/* We do broadcast packet on the IPX_MAX_PPROP_HOPS hop, but we
	 * process it locally. All previous hops broadcasted it, and process it
	 * locally. */
	if (IPX_SKB_CB(skb)->ipx_tctrl == IPX_MAX_PPROP_HOPS)
		goto out;

	c = ((u8 *) ipx) + sizeof(struct ipxhdr);
	l = (__be32 *) c;

	/* Don't broadcast packet if already seen this net */
	for (i = 0; i < IPX_SKB_CB(skb)->ipx_tctrl; i++)
		if (*l++ == intrfc->if_netnum)
			goto out;

	/* < IPX_MAX_PPROP_HOPS hops && input interface not in list. Save the
	 * position where we will insert recvd netnum into list, later on,
	 * in ipxitf_send */
	IPX_SKB_CB(skb)->last_hop.index = i;
	IPX_SKB_CB(skb)->last_hop.netnum = intrfc->if_netnum;
	/* xmit on all other interfaces... */
	spin_lock_bh(&ipx_interfaces_lock);
	list_for_each_entry(ifcs, &ipx_interfaces, node) {
		/* Except unconfigured interfaces */
		if (!ifcs->if_netnum)
			continue;

		/* That aren't in the list */
		if (ifcs == intrfc)
			continue;
		l = (__be32 *) c;
		/* don't consider the last entry in the packet list,
		 * it is our netnum, and it is not there yet */
		for (i = 0; i < IPX_SKB_CB(skb)->ipx_tctrl; i++)
			if (ifcs->if_netnum == *l++)
				break;
		if (i == IPX_SKB_CB(skb)->ipx_tctrl) {
			struct sk_buff *s = skb_copy(skb, GFP_ATOMIC);

			if (s) {
				IPX_SKB_CB(s)->ipx_dest_net = ifcs->if_netnum;
				ipxrtr_route_skb(s);
			}
		}
	}
	spin_unlock_bh(&ipx_interfaces_lock);
out:
	return rc;
}

static void ipxitf_insert(struct ipx_interface *intrfc)
{
	spin_lock_bh(&ipx_interfaces_lock);
	list_add_tail(&intrfc->node, &ipx_interfaces);
	spin_unlock_bh(&ipx_interfaces_lock);

	if (ipxcfg_auto_select_primary && !ipx_primary_net)
		ipx_primary_net = intrfc;
}

static struct ipx_interface *ipxitf_alloc(struct net_device *dev, __be32 netnum,
					  __be16 dlink_type,
					  struct datalink_proto *dlink,
					  unsigned char internal,
					  int ipx_offset)
{
	struct ipx_interface *intrfc = kmalloc(sizeof(*intrfc), GFP_ATOMIC);

	if (intrfc) {
		intrfc->if_dev		= dev;
		intrfc->if_netnum	= netnum;
		intrfc->if_dlink_type 	= dlink_type;
		intrfc->if_dlink 	= dlink;
		intrfc->if_internal 	= internal;
		intrfc->if_ipx_offset 	= ipx_offset;
		intrfc->if_sknum 	= IPX_MIN_EPHEMERAL_SOCKET;
		INIT_HLIST_HEAD(&intrfc->if_sklist);
		atomic_set(&intrfc->refcnt, 1);
		spin_lock_init(&intrfc->if_sklist_lock);
	}

	return intrfc;
}

static int ipxitf_create_internal(struct ipx_interface_definition *idef)
{
	struct ipx_interface *intrfc;
	int rc = -EEXIST;

	/* Only one primary network allowed */
	if (ipx_primary_net)
		goto out;

	/* Must have a valid network number */
	rc = -EADDRNOTAVAIL;
	if (!idef->ipx_network)
		goto out;
	intrfc = ipxitf_find_using_net(idef->ipx_network);
	rc = -EADDRINUSE;
	if (intrfc) {
		ipxitf_put(intrfc);
		goto out;
	}
	intrfc = ipxitf_alloc(NULL, idef->ipx_network, 0, NULL, 1, 0);
	rc = -EAGAIN;
	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);

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

static __be16 ipx_map_frame_type(unsigned char type)
{
	__be16 rc = 0;

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

	return rc;
}

static int ipxitf_create(struct ipx_interface_definition *idef)
{
	struct net_device *dev;
	__be16 dlink_type = 0;
	struct datalink_proto *datalink = NULL;
	struct ipx_interface *intrfc;
	int rc;

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

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

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

	if (intrfc)
		ipxitf_put(intrfc);

	dev = dev_get_by_name(&init_net, idef->ipx_device);
	rc = -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 	= htons(ETH_P_802_2);
		datalink 	= p8022_datalink;
		break;
	case IPX_FRAME_ETHERII:
		if (dev->type != ARPHRD_IEEE802) {
			dlink_type 	= 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 	= htons(ETH_P_SNAP);
		datalink 	= pSNAP_datalink;
		break;
	case IPX_FRAME_8023:
		dlink_type 	= htons(ETH_P_802_3);
		datalink 	= p8023_datalink;
		break;
	case IPX_FRAME_NONE:
	default:
		rc = -EPROTONOSUPPORT;
		goto out_dev;
	}

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

	/* Check addresses are suitable */
	rc = -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);