Commit 8dc57da2 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'ipv6-firewire' 



YOSHIFUJI Hideaki says:

====================
This is take 4 of supporting IPv6 over Firewire (IEEE 1394) based on
RFC3146.

Take 3->4:
- Fix receiving 1394 ARP, which comes without arp$tha.
- Remove rfc3146 unit directory on module exit.
- other minor clean-ups - minimize diffs.

====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents b8092861 cb6bf355

drivers/firewire/Kconfig

+3 −3
Original line number Diff line number Diff line
@@ -47,9 +47,9 @@ config FIREWIRE_NET 
	tristate "IP networking over 1394"

	depends on FIREWIRE && INET

	help

	  This enables IPv4 over IEEE 1394, providing IP connectivity with

	  other implementations of RFC 2734 as found on several operating

	  systems.  Multicast support is currently limited.

	  This enables IPv4/IPv6 over IEEE 1394, providing IP connectivity

	  with other implementations of RFC 2734/3146 as found on several

	  operating systems.  Multicast support is currently limited.



	  To compile this driver as a module, say M here:  The module will be

	  called firewire-net.

drivers/firewire/net.c

+135 −166
Original line number Diff line number Diff line 
/*

 * IPv4 over IEEE 1394, per RFC 2734

 * IPv6 over IEEE 1394, per RFC 3146

 *

 * Copyright (C) 2009 Jay Fenlason <fenlason@redhat.com>

 *
@@ -28,6 +29,7 @@ 


#include <asm/unaligned.h>

#include <net/arp.h>

#include <net/firewire.h>



/* rx limits */

#define FWNET_MAX_FRAGMENTS		30 /* arbitrary, > TX queue depth */
@@ -45,6 +47,7 @@ 


#define IANA_SPECIFIER_ID		0x00005eU

#define RFC2734_SW_VERSION		0x000001U

#define RFC3146_SW_VERSION		0x000002U



#define IEEE1394_GASP_HDR_SIZE	8
@@ -57,32 +60,10 @@ 
#define RFC2374_HDR_LASTFRAG	2	/* last fragment	*/

#define RFC2374_HDR_INTFRAG	3	/* interior fragment	*/



#define RFC2734_HW_ADDR_LEN	16



struct rfc2734_arp {

	__be16 hw_type;		/* 0x0018	*/

	__be16 proto_type;	/* 0x0806       */

	u8 hw_addr_len;		/* 16		*/

	u8 ip_addr_len;		/* 4		*/

	__be16 opcode;		/* ARP Opcode	*/

	/* Above is exactly the same format as struct arphdr */



	__be64 s_uniq_id;	/* Sender's 64bit EUI			*/

	u8 max_rec;		/* Sender's max packet size		*/

	u8 sspd;		/* Sender's max speed			*/

	__be16 fifo_hi;		/* hi 16bits of sender's FIFO addr	*/

	__be32 fifo_lo;		/* lo 32bits of sender's FIFO addr	*/

	__be32 sip;		/* Sender's IP Address			*/

	__be32 tip;		/* IP Address of requested hw addr	*/

} __packed;



/* This header format is specific to this driver implementation. */

#define FWNET_ALEN	8

#define FWNET_HLEN	10

struct fwnet_header {

	u8 h_dest[FWNET_ALEN];	/* destination address */

	__be16 h_proto;		/* packet type ID field */

} __packed;

static bool fwnet_hwaddr_is_multicast(u8 *ha)

{

	return !!(*ha & 1);

}



/* IPv4 and IPv6 encapsulation header */

struct rfc2734_header {
@@ -191,8 +172,6 @@ struct fwnet_peer { 
	struct list_head peer_link;

	struct fwnet_device *dev;

	u64 guid;

	u64 fifo;

	__be32 ip;



	/* guarded by dev->lock */

	struct list_head pd_list; /* received partial datagrams */
@@ -221,6 +200,15 @@ struct fwnet_packet_task { 
	u8 enqueued;

};



/*

 * Get fifo address embedded in hwaddr

 */

static __u64 fwnet_hwaddr_fifo(union fwnet_hwaddr *ha)

{

	return (u64)get_unaligned_be16(&ha->uc.fifo_hi) << 32

	       | get_unaligned_be32(&ha->uc.fifo_lo);

}



/*

 * saddr == NULL means use device source address.

 * daddr == NULL means leave destination address (eg unresolved arp).
@@ -513,10 +501,20 @@ static int fwnet_finish_incoming_packet(struct net_device *net, 
					bool is_broadcast, u16 ether_type)

{

	struct fwnet_device *dev;

	static const __be64 broadcast_hw = cpu_to_be64(~0ULL);

	int status;

	__be64 guid;



	switch (ether_type) {

	case ETH_P_ARP:

	case ETH_P_IP:

#if IS_ENABLED(CONFIG_IPV6)

	case ETH_P_IPV6:

#endif

		break;

	default:

		goto err;

	}



	dev = netdev_priv(net);

	/* Write metadata, and then pass to the receive level */

	skb->dev = net;
@@ -524,92 +522,11 @@ static int fwnet_finish_incoming_packet(struct net_device *net, 


	/*

	 * Parse the encapsulation header. This actually does the job of

	 * converting to an ethernet frame header, as well as arp

	 * conversion if needed. ARP conversion is easier in this

	 * direction, since we are using ethernet as our backend.

	 * converting to an ethernet-like pseudo frame header.

	 */

	/*

	 * If this is an ARP packet, convert it. First, we want to make

	 * use of some of the fields, since they tell us a little bit

	 * about the sending machine.

	 */

	if (ether_type == ETH_P_ARP) {

		struct rfc2734_arp *arp1394;

		struct arphdr *arp;

		unsigned char *arp_ptr;

		u64 fifo_addr;

		u64 peer_guid;

		unsigned sspd;

		u16 max_payload;

		struct fwnet_peer *peer;

		unsigned long flags;



		arp1394   = (struct rfc2734_arp *)skb->data;

		arp       = (struct arphdr *)skb->data;

		arp_ptr   = (unsigned char *)(arp + 1);

		peer_guid = get_unaligned_be64(&arp1394->s_uniq_id);

		fifo_addr = (u64)get_unaligned_be16(&arp1394->fifo_hi) << 32

				| get_unaligned_be32(&arp1394->fifo_lo);



		sspd = arp1394->sspd;

		/* Sanity check.  OS X 10.3 PPC reportedly sends 131. */

		if (sspd > SCODE_3200) {

			dev_notice(&net->dev, "sspd %x out of range\n", sspd);

			sspd = SCODE_3200;

		}

		max_payload = fwnet_max_payload(arp1394->max_rec, sspd);



		spin_lock_irqsave(&dev->lock, flags);

		peer = fwnet_peer_find_by_guid(dev, peer_guid);

		if (peer) {

			peer->fifo = fifo_addr;



			if (peer->speed > sspd)

				peer->speed = sspd;

			if (peer->max_payload > max_payload)

				peer->max_payload = max_payload;



			peer->ip = arp1394->sip;

		}

		spin_unlock_irqrestore(&dev->lock, flags);



		if (!peer) {

			dev_notice(&net->dev,

				   "no peer for ARP packet from %016llx\n",

				   (unsigned long long)peer_guid);

			goto no_peer;

		}



		/*

		 * Now that we're done with the 1394 specific stuff, we'll

		 * need to alter some of the data.  Believe it or not, all

		 * that needs to be done is sender_IP_address needs to be

		 * moved, the destination hardware address get stuffed

		 * in and the hardware address length set to 8.

		 *

		 * IMPORTANT: The code below overwrites 1394 specific data

		 * needed above so keep the munging of the data for the

		 * higher level IP stack last.

		 */



		arp->ar_hln = 8;

		/* skip over sender unique id */

		arp_ptr += arp->ar_hln;

		/* move sender IP addr */

		put_unaligned(arp1394->sip, (u32 *)arp_ptr);

		/* skip over sender IP addr */

		arp_ptr += arp->ar_pln;



		if (arp->ar_op == htons(ARPOP_REQUEST))

			memset(arp_ptr, 0, sizeof(u64));

		else

			memcpy(arp_ptr, net->dev_addr, sizeof(u64));

	}



	/* Now add the ethernet header. */

	guid = cpu_to_be64(dev->card->guid);

	if (dev_hard_header(skb, net, ether_type,

			   is_broadcast ? &broadcast_hw : &guid,

			   is_broadcast ? net->broadcast : net->dev_addr,

			   NULL, skb->len) >= 0) {

		struct fwnet_header *eth;

		u16 *rawp;
@@ -618,7 +535,7 @@ static int fwnet_finish_incoming_packet(struct net_device *net, 
		skb_reset_mac_header(skb);

		skb_pull(skb, sizeof(*eth));

		eth = (struct fwnet_header *)skb_mac_header(skb);

		if (*eth->h_dest & 1) {

		if (fwnet_hwaddr_is_multicast(eth->h_dest)) {

			if (memcmp(eth->h_dest, net->broadcast,

				   net->addr_len) == 0)

				skb->pkt_type = PACKET_BROADCAST;
@@ -652,7 +569,7 @@ static int fwnet_finish_incoming_packet(struct net_device *net, 


	return 0;



 no_peer:

 err:

	net->stats.rx_errors++;

	net->stats.rx_dropped++;
@@ -856,7 +773,12 @@ static void fwnet_receive_broadcast(struct fw_iso_context *context, 
	ver = be32_to_cpu(buf_ptr[1]) & 0xffffff;

	source_node_id = be32_to_cpu(buf_ptr[0]) >> 16;



	if (specifier_id == IANA_SPECIFIER_ID && ver == RFC2734_SW_VERSION) {

	if (specifier_id == IANA_SPECIFIER_ID &&

	    (ver == RFC2734_SW_VERSION

#if IS_ENABLED(CONFIG_IPV6)

	     || ver == RFC3146_SW_VERSION

#endif

	    )) {

		buf_ptr += 2;

		length -= IEEE1394_GASP_HDR_SIZE;

		fwnet_incoming_packet(dev, buf_ptr, length, source_node_id,
@@ -1059,16 +981,27 @@ static int fwnet_send_packet(struct fwnet_packet_task *ptask) 
		u8 *p;

		int generation;

		int node_id;

		unsigned int sw_version;



		/* ptask->generation may not have been set yet */

		generation = dev->card->generation;

		smp_rmb();

		node_id = dev->card->node_id;



		switch (ptask->skb->protocol) {

		default:

			sw_version = RFC2734_SW_VERSION;

			break;

#if IS_ENABLED(CONFIG_IPV6)

		case htons(ETH_P_IPV6):

			sw_version = RFC3146_SW_VERSION;

#endif

		}



		p = skb_push(ptask->skb, IEEE1394_GASP_HDR_SIZE);

		put_unaligned_be32(node_id << 16 | IANA_SPECIFIER_ID >> 8, p);

		put_unaligned_be32((IANA_SPECIFIER_ID & 0xff) << 24

						| RFC2734_SW_VERSION, &p[4]);

						| sw_version, &p[4]);



		/* We should not transmit if broadcast_channel.valid == 0. */

		fw_send_request(dev->card, &ptask->transaction,
@@ -1272,13 +1205,9 @@ static int fwnet_open(struct net_device *net) 
	struct fwnet_device *dev = netdev_priv(net);

	int ret;



	ret = fwnet_fifo_start(dev);

	if (ret)

		return ret;



	ret = fwnet_broadcast_start(dev);

	if (ret)

		goto out;

		return ret;



	netif_start_queue(net);
@@ -1287,9 +1216,6 @@ static int fwnet_open(struct net_device *net) 
	spin_unlock_irq(&dev->lock);



	return 0;

out:

	fwnet_fifo_stop(dev);

	return ret;

}



/* ifdown */
@@ -1298,9 +1224,7 @@ static int fwnet_stop(struct net_device *net) 
	struct fwnet_device *dev = netdev_priv(net);



	netif_stop_queue(net);



	fwnet_broadcast_stop(dev);

	fwnet_fifo_stop(dev);



	return 0;

}
@@ -1340,19 +1264,27 @@ static netdev_tx_t fwnet_tx(struct sk_buff *skb, struct net_device *net) 
	 * We might need to rebuild the header on tx failure.

	 */

	memcpy(&hdr_buf, skb->data, sizeof(hdr_buf));

	skb_pull(skb, sizeof(hdr_buf));



	proto = hdr_buf.h_proto;



	switch (proto) {

	case htons(ETH_P_ARP):

	case htons(ETH_P_IP):

#if IS_ENABLED(CONFIG_IPV6)

	case htons(ETH_P_IPV6):

#endif

		break;

	default:

		goto fail;

	}



	skb_pull(skb, sizeof(hdr_buf));

	dg_size = skb->len;



	/*

	 * Set the transmission type for the packet.  ARP packets and IP

	 * broadcast packets are sent via GASP.

	 */

	if (memcmp(hdr_buf.h_dest, net->broadcast, FWNET_ALEN) == 0

	    || proto == htons(ETH_P_ARP)

	    || (proto == htons(ETH_P_IP)

		&& IN_MULTICAST(ntohl(ip_hdr(skb)->daddr)))) {

	if (fwnet_hwaddr_is_multicast(hdr_buf.h_dest)) {

		max_payload        = dev->broadcast_xmt_max_payload;

		datagram_label_ptr = &dev->broadcast_xmt_datagramlabel;
@@ -1361,11 +1293,12 @@ static netdev_tx_t fwnet_tx(struct sk_buff *skb, struct net_device *net) 
		ptask->dest_node   = IEEE1394_ALL_NODES;

		ptask->speed       = SCODE_100;

	} else {

		__be64 guid = get_unaligned((__be64 *)hdr_buf.h_dest);

		union fwnet_hwaddr *ha = (union fwnet_hwaddr *)hdr_buf.h_dest;

		__be64 guid = get_unaligned(&ha->uc.uniq_id);

		u8 generation;



		peer = fwnet_peer_find_by_guid(dev, be64_to_cpu(guid));

		if (!peer || peer->fifo == FWNET_NO_FIFO_ADDR)

		if (!peer)

			goto fail;



		generation         = peer->generation;
@@ -1373,32 +1306,12 @@ static netdev_tx_t fwnet_tx(struct sk_buff *skb, struct net_device *net) 
		max_payload        = peer->max_payload;

		datagram_label_ptr = &peer->datagram_label;



		ptask->fifo_addr   = peer->fifo;

		ptask->fifo_addr   = fwnet_hwaddr_fifo(ha);

		ptask->generation  = generation;

		ptask->dest_node   = dest_node;

		ptask->speed       = peer->speed;

	}



	/* If this is an ARP packet, convert it */

	if (proto == htons(ETH_P_ARP)) {

		struct arphdr *arp = (struct arphdr *)skb->data;

		unsigned char *arp_ptr = (unsigned char *)(arp + 1);

		struct rfc2734_arp *arp1394 = (struct rfc2734_arp *)skb->data;

		__be32 ipaddr;



		ipaddr = get_unaligned((__be32 *)(arp_ptr + FWNET_ALEN));



		arp1394->hw_addr_len    = RFC2734_HW_ADDR_LEN;

		arp1394->max_rec        = dev->card->max_receive;

		arp1394->sspd		= dev->card->link_speed;



		put_unaligned_be16(dev->local_fifo >> 32,

				   &arp1394->fifo_hi);

		put_unaligned_be32(dev->local_fifo & 0xffffffff,

				   &arp1394->fifo_lo);

		put_unaligned(ipaddr, &arp1394->sip);

	}



	ptask->hdr.w0 = 0;

	ptask->hdr.w1 = 0;

	ptask->skb = skb;
@@ -1513,8 +1426,6 @@ static int fwnet_add_peer(struct fwnet_device *dev, 


	peer->dev = dev;

	peer->guid = (u64)device->config_rom[3] << 32 | device->config_rom[4];

	peer->fifo = FWNET_NO_FIFO_ADDR;

	peer->ip = 0;

	INIT_LIST_HEAD(&peer->pd_list);

	peer->pdg_size = 0;

	peer->datagram_label = 0;
@@ -1544,6 +1455,7 @@ static int fwnet_probe(struct device *_dev) 
	struct fwnet_device *dev;

	unsigned max_mtu;

	int ret;

	union fwnet_hwaddr *ha;



	mutex_lock(&fwnet_device_mutex);
@@ -1574,6 +1486,11 @@ static int fwnet_probe(struct device *_dev) 
	dev->card = card;

	dev->netdev = net;



	ret = fwnet_fifo_start(dev);

	if (ret < 0)

		goto out;

	dev->local_fifo = dev->handler.offset;



	/*

	 * Use the RFC 2734 default 1500 octets or the maximum payload

	 * as initial MTU
@@ -1583,24 +1500,31 @@ static int fwnet_probe(struct device *_dev) 
	net->mtu = min(1500U, max_mtu);



	/* Set our hardware address while we're at it */

	put_unaligned_be64(card->guid, net->dev_addr);

	put_unaligned_be64(~0ULL, net->broadcast);

	ha = (union fwnet_hwaddr *)net->dev_addr;

	put_unaligned_be64(card->guid, &ha->uc.uniq_id);

	ha->uc.max_rec = dev->card->max_receive;

	ha->uc.sspd = dev->card->link_speed;

	put_unaligned_be16(dev->local_fifo >> 32, &ha->uc.fifo_hi);

	put_unaligned_be32(dev->local_fifo & 0xffffffff, &ha->uc.fifo_lo);



	memset(net->broadcast, -1, net->addr_len);



	ret = register_netdev(net);

	if (ret)

		goto out;



	list_add_tail(&dev->dev_link, &fwnet_device_list);

	dev_notice(&net->dev, "IPv4 over IEEE 1394 on card %s\n",

	dev_notice(&net->dev, "IP over IEEE 1394 on card %s\n",

		   dev_name(card->device));

 have_dev:

	ret = fwnet_add_peer(dev, unit, device);

	if (ret && allocated_netdev) {

		unregister_netdev(net);

		list_del(&dev->dev_link);

	}

 out:

	if (ret && allocated_netdev)

		fwnet_fifo_stop(dev);

		free_netdev(net);

	}



	mutex_unlock(&fwnet_device_mutex);
@@ -1633,14 +1557,14 @@ static int fwnet_remove(struct device *_dev) 
	mutex_lock(&fwnet_device_mutex);



	net = dev->netdev;

	if (net && peer->ip)

		arp_invalidate(net, peer->ip);



	fwnet_remove_peer(peer, dev);



	if (list_empty(&dev->peer_list)) {

		unregister_netdev(net);



		fwnet_fifo_stop(dev);



		for (i = 0; dev->queued_datagrams && i < 5; i++)

			ssleep(1);

		WARN_ON(dev->queued_datagrams);
@@ -1679,6 +1603,14 @@ static const struct ieee1394_device_id fwnet_id_table[] = { 
		.specifier_id = IANA_SPECIFIER_ID,

		.version      = RFC2734_SW_VERSION,

	},

#if IS_ENABLED(CONFIG_IPV6)

	{

		.match_flags  = IEEE1394_MATCH_SPECIFIER_ID |

				IEEE1394_MATCH_VERSION,

		.specifier_id = IANA_SPECIFIER_ID,

		.version      = RFC3146_SW_VERSION,

	},

#endif

	{ }

};
@@ -1716,6 +1648,30 @@ static struct fw_descriptor rfc2374_unit_directory = { 
	.data   = rfc2374_unit_directory_data

};



#if IS_ENABLED(CONFIG_IPV6)

static const u32 rfc3146_unit_directory_data[] = {

	0x00040000,	/* directory_length		*/

	0x1200005e,	/* unit_specifier_id: IANA	*/

	0x81000003,	/* textual descriptor offset	*/

	0x13000002,	/* unit_sw_version: RFC 3146	*/

	0x81000005,	/* textual descriptor offset	*/

	0x00030000,	/* descriptor_length		*/

	0x00000000,	/* text				*/

	0x00000000,	/* minimal ASCII, en		*/

	0x49414e41,	/* I A N A			*/

	0x00030000,	/* descriptor_length		*/

	0x00000000,	/* text				*/

	0x00000000,	/* minimal ASCII, en		*/

	0x49507636,	/* I P v 6			*/

};



static struct fw_descriptor rfc3146_unit_directory = {

	.length = ARRAY_SIZE(rfc3146_unit_directory_data),

	.key    = (CSR_DIRECTORY | CSR_UNIT) << 24,

	.data   = rfc3146_unit_directory_data

};

#endif



static int __init fwnet_init(void)

{

	int err;
@@ -1724,11 +1680,17 @@ static int __init fwnet_init(void) 
	if (err)

		return err;



#if IS_ENABLED(CONFIG_IPV6)

	err = fw_core_add_descriptor(&rfc3146_unit_directory);

	if (err)

		goto out;

#endif



	fwnet_packet_task_cache = kmem_cache_create("packet_task",

			sizeof(struct fwnet_packet_task), 0, 0, NULL);

	if (!fwnet_packet_task_cache) {

		err = -ENOMEM;

		goto out;

		goto out2;

	}



	err = driver_register(&fwnet_driver.driver);
@@ -1736,7 +1698,11 @@ static int __init fwnet_init(void) 
		return 0;



	kmem_cache_destroy(fwnet_packet_task_cache);

out2:

#if IS_ENABLED(CONFIG_IPV6)

	fw_core_remove_descriptor(&rfc3146_unit_directory);

out:

#endif

	fw_core_remove_descriptor(&rfc2374_unit_directory);



	return err;
@@ -1747,11 +1713,14 @@ static void __exit fwnet_cleanup(void) 
{

	driver_unregister(&fwnet_driver.driver);

	kmem_cache_destroy(fwnet_packet_task_cache);

#if IS_ENABLED(CONFIG_IPV6)

	fw_core_remove_descriptor(&rfc3146_unit_directory);

#endif

	fw_core_remove_descriptor(&rfc2374_unit_directory);

}

module_exit(fwnet_cleanup);



MODULE_AUTHOR("Jay Fenlason <fenlason@redhat.com>");

MODULE_DESCRIPTION("IPv4 over IEEE1394 as per RFC 2734");

MODULE_DESCRIPTION("IP over IEEE1394 as per RFC 2734/3146");

MODULE_LICENSE("GPL");

MODULE_DEVICE_TABLE(ieee1394, fwnet_id_table);

include/linux/if_arp.h

+10 −2
Original line number Diff line number Diff line
@@ -33,7 +33,15 @@ static inline struct arphdr *arp_hdr(const struct sk_buff *skb) 


static inline int arp_hdr_len(struct net_device *dev)

{

	switch (dev->type) {

#if IS_ENABLED(CONFIG_FIREWIRE_NET)

	case ARPHRD_IEEE1394:

		/* ARP header, device address and 2 IP addresses */

		return sizeof(struct arphdr) + dev->addr_len + sizeof(u32) * 2;

#endif

	default:

		/* ARP header, plus 2 device addresses, plus 2 IP addresses. */

		return sizeof(struct arphdr) + (dev->addr_len + sizeof(u32)) * 2;

	}

}

#endif	/* _LINUX_IF_ARP_H */

include/net/firewire.h

0 → 100644
+25 −0
Original line number Diff line number Diff line 
#ifndef _NET_FIREWIRE_H

#define _NET_FIREWIRE_H



/* Pseudo L2 address */

#define FWNET_ALEN	16

union fwnet_hwaddr {

	u8 u[FWNET_ALEN];

	/* "Hardware address" defined in RFC2734/RF3146 */

	struct {

		__be64 uniq_id;		/* EUI-64			*/

		u8 max_rec;		/* max packet size		*/

		u8 sspd;		/* max speed			*/

		__be16 fifo_hi;		/* hi 16bits of FIFO addr	*/

		__be32 fifo_lo;		/* lo 32bits of FIFO addr	*/

	} __packed uc;

};



/* Pseudo L2 Header */

#define FWNET_HLEN	18

struct fwnet_header {

	u8 h_dest[FWNET_ALEN];	/* destination address */

	__be16 h_proto;		/* packet type ID field */

} __packed;



#endif

net/ipv4/arp.c

+21 −6
Original line number Diff line number Diff line
@@ -654,11 +654,19 @@ struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip, 
	arp_ptr += dev->addr_len;

	memcpy(arp_ptr, &src_ip, 4);

	arp_ptr += 4;



	switch (dev->type) {

#if IS_ENABLED(CONFIG_FIREWIRE_NET)

	case ARPHRD_IEEE1394:

		break;

#endif

	default:

		if (target_hw != NULL)

			memcpy(arp_ptr, target_hw, dev->addr_len);

		else

			memset(arp_ptr, 0, dev->addr_len);

		arp_ptr += dev->addr_len;

	}

	memcpy(arp_ptr, &dest_ip, 4);



	return skb;
@@ -781,7 +789,14 @@ static int arp_process(struct sk_buff *skb) 
	arp_ptr += dev->addr_len;

	memcpy(&sip, arp_ptr, 4);

	arp_ptr += 4;

	switch (dev_type) {

#if IS_ENABLED(CONFIG_FIREWIRE_NET)

	case ARPHRD_IEEE1394:

		break;

#endif

	default:

		arp_ptr += dev->addr_len;

	}

	memcpy(&tip, arp_ptr, 4);

/*

 *	Check for bad requests for 127.x.x.x and requests for multicast

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