drivers/net/arcnet/capmode.c - kernel/quantenna - Git at Google

 /*
  * Linux ARCnet driver - "cap mode" packet encapsulation.
  * It adds sequence numbers to packets for communicating between a user space
  * application and the driver. After a transmit it sends a packet with protocol
  * byte 0 back up to the userspace containing the sequence number of the packet
  * plus the transmit-status on the ArcNet.
  *
  * Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
  * Derived from arc-rawmode.c by Avery Pennarun.
  * arc-rawmode was in turned based on skeleton.c, see below.
  *
  * **********************
  *
  * The original copyright of skeleton.c was as follows:
  *
  * skeleton.c Written 1993 by Donald Becker.
  * Copyright 1993 United States Government as represented by the
  * Director, National Security Agency.  This software may only be used
  * and distributed according to the terms of the GNU General Public License as
  * modified by SRC, incorporated herein by reference.
  *
  * **********************
  *
  * For more details, see drivers/net/arcnet.c
  *
  * **********************
  */

 #define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt

 #include <linux/module.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/if_arp.h>
 #include <net/arp.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>

 #include "arcdevice.h"

 /* packet receiver */
 static void rx(struct net_device *dev, int bufnum,
 	       struct archdr *pkthdr, int length)
 {
 	struct arcnet_local *lp = netdev_priv(dev);
 	struct sk_buff *skb;
 	struct archdr *pkt = pkthdr;
 	char *pktbuf, *pkthdrbuf;
 	int ofs;

 	arc_printk(D_DURING, dev, "it's a raw(cap) packet (length=%d)\n",
 		   length);

 	if (length >= MinTU)
 		ofs = 512 - length;
 	else
 		ofs = 256 - length;

 	skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
 	if (!skb) {
 		dev->stats.rx_dropped++;
 		return;
 	}
 	skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
 	skb->dev = dev;
 	skb_reset_mac_header(skb);
 	pkt = (struct archdr *)skb_mac_header(skb);
 	skb_pull(skb, ARC_HDR_SIZE);

 	/* up to sizeof(pkt->soft) has already been copied from the card
 	 * squeeze in an int for the cap encapsulation
 	 * use these variables to be sure we count in bytes, not in
 	 * sizeof(struct archdr)
 	 */
 	pktbuf = (char *)pkt;
 	pkthdrbuf = (char *)pkthdr;
 	memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto));
 	memcpy(pktbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto) + sizeof(int),
 	       pkthdrbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto),
 	       sizeof(struct archdr) - ARC_HDR_SIZE - sizeof(pkt->soft.cap.proto));

 	if (length > sizeof(pkt->soft))
 		lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 				      pkt->soft.raw + sizeof(pkt->soft)
 				      + sizeof(int),
 				      length - sizeof(pkt->soft));

 	if (BUGLVL(D_SKB))
 		arcnet_dump_skb(dev, skb, "rx");

 	skb->protocol = cpu_to_be16(ETH_P_ARCNET);
 	netif_rx(skb);
 }

 /* Create the ARCnet hard/soft headers for cap mode.
  * There aren't any soft headers in cap mode - not even the protocol id.
  */
 static int build_header(struct sk_buff *skb,
 			struct net_device *dev,
 			unsigned short type,
 			uint8_t daddr)
 {
 	int hdr_size = ARC_HDR_SIZE;
 	struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);

 	arc_printk(D_PROTO, dev, "Preparing header for cap packet %x.\n",
 		   *((int *)&pkt->soft.cap.cookie[0]));

 	/* Set the source hardware address.
 	 *
 	 * This is pretty pointless for most purposes, but it can help in
 	 * debugging.  ARCnet does not allow us to change the source address in
 	 * the actual packet sent)
 	 */
 	pkt->hard.source = *dev->dev_addr;

 	/* see linux/net/ethernet/eth.c to see where I got the following */

 	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 		/* FIXME: fill in the last byte of the dest ipaddr here to
 		 * better comply with RFC1051 in "noarp" mode.
 		 */
 		pkt->hard.dest = 0;
 		return hdr_size;
 	}
 	/* otherwise, just fill it in and go! */
 	pkt->hard.dest = daddr;

 	return hdr_size;	/* success */
 }

 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 		      int bufnum)
 {
 	struct arcnet_local *lp = netdev_priv(dev);
 	struct arc_hardware *hard = &pkt->hard;
 	int ofs;

 	/* hard header is not included in packet length */
 	length -= ARC_HDR_SIZE;
 	/* And neither is the cookie field */
 	length -= sizeof(int);

 	arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
 		   lp->next_tx, lp->cur_tx, bufnum);

 	arc_printk(D_PROTO, dev, "Sending for cap packet %x.\n",
 		   *((int *)&pkt->soft.cap.cookie[0]));

 	if (length > XMTU) {
 		/* should never happen! other people already check for this. */
 		arc_printk(D_NORMAL, dev, "Bug!  prepare_tx with size %d (> %d)\n",
 			   length, XMTU);
 		length = XMTU;
 	}
 	if (length > MinTU) {
 		hard->offset[0] = 0;
 		hard->offset[1] = ofs = 512 - length;
 	} else if (length > MTU) {
 		hard->offset[0] = 0;
 		hard->offset[1] = ofs = 512 - length - 3;
 	} else {
 		hard->offset[0] = ofs = 256 - length;
 	}

 	arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n",
 		   length, ofs);

 	/* Copy the arcnet-header + the protocol byte down: */
 	lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 	lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
 			    sizeof(pkt->soft.cap.proto));

 	/* Skip the extra integer we have written into it as a cookie
 	 * but write the rest of the message:
 	 */
 	lp->hw.copy_to_card(dev, bufnum, ofs + 1,
 			    ((unsigned char *)&pkt->soft.cap.mes), length - 1);

 	lp->lastload_dest = hard->dest;

 	return 1;	/* done */
 }

 static int ack_tx(struct net_device *dev, int acked)
 {
 	struct arcnet_local *lp = netdev_priv(dev);
 	struct sk_buff *ackskb;
 	struct archdr *ackpkt;
 	int length = sizeof(struct arc_cap);

 	arc_printk(D_DURING, dev, "capmode: ack_tx: protocol: %x: result: %d\n",
 		   lp->outgoing.skb->protocol, acked);

 	if (BUGLVL(D_SKB))
 		arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");

 	/* Now alloc a skb to send back up through the layers: */
 	ackskb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
 	if (!ackskb)
 		goto free_outskb;

 	skb_put(ackskb, length + ARC_HDR_SIZE);
 	ackskb->dev = dev;

 	skb_reset_mac_header(ackskb);
 	ackpkt = (struct archdr *)skb_mac_header(ackskb);
 	/* skb_pull(ackskb, ARC_HDR_SIZE); */

 	skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
 				  ARC_HDR_SIZE + sizeof(struct arc_cap));
 	ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
 	ackpkt->soft.cap.mes.ack = acked;

 	arc_printk(D_PROTO, dev, "Ackknowledge for cap packet %x.\n",
 		   *((int *)&ackpkt->soft.cap.cookie[0]));

 	ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);

 	if (BUGLVL(D_SKB))
 		arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
 	netif_rx(ackskb);

 free_outskb:
 	dev_kfree_skb_irq(lp->outgoing.skb);
 	lp->outgoing.proto = NULL;
 			/* We are always finished when in this protocol */

 	return 0;
 }

 static struct ArcProto capmode_proto = {
 	.suffix		= 'r',
 	.mtu		= XMTU,
 	.rx		= rx,
 	.build_header	= build_header,
 	.prepare_tx	= prepare_tx,
 	.ack_tx		= ack_tx
 };

 static int __init capmode_module_init(void)
 {
 	int count;

 	pr_info("cap mode (`c') encapsulation support loaded\n");

 	for (count = 1; count <= 8; count++)
 		if (arc_proto_map[count] == arc_proto_default)
 			arc_proto_map[count] = &capmode_proto;

 	/* for cap mode, we only set the bcast proto if there's no better one */
 	if (arc_bcast_proto == arc_proto_default)
 		arc_bcast_proto = &capmode_proto;

 	arc_proto_default = &capmode_proto;
 	arc_raw_proto = &capmode_proto;

 	return 0;
 }

 static void __exit capmode_module_exit(void)
 {
 	arcnet_unregister_proto(&capmode_proto);
 }
 module_init(capmode_module_init);
 module_exit(capmode_module_exit);

 MODULE_LICENSE("GPL");
	/*
	* Linux ARCnet driver - "cap mode" packet encapsulation.
	* It adds sequence numbers to packets for communicating between a user space
	* application and the driver. After a transmit it sends a packet with protocol
	* byte 0 back up to the userspace containing the sequence number of the packet
	* plus the transmit-status on the ArcNet.
	*
	* Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
	* Derived from arc-rawmode.c by Avery Pennarun.
	* arc-rawmode was in turned based on skeleton.c, see below.
	*
	* **********************
	*
	* The original copyright of skeleton.c was as follows:
	*
	* skeleton.c Written 1993 by Donald Becker.
	* Copyright 1993 United States Government as represented by the
	* Director, National Security Agency. This software may only be used
	* and distributed according to the terms of the GNU General Public License as
	* modified by SRC, incorporated herein by reference.
	*
	* **********************
	*
	* For more details, see drivers/net/arcnet.c
	*
	* **********************
	*/

	#define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt

	#include <linux/module.h>
	#include <linux/gfp.h>
	#include <linux/init.h>
	#include <linux/if_arp.h>
	#include <net/arp.h>
	#include <linux/netdevice.h>
	#include <linux/skbuff.h>

	#include "arcdevice.h"

	/* packet receiver */
	static void rx(struct net_device *dev, int bufnum,
	struct archdr *pkthdr, int length)
	{
	struct arcnet_local *lp = netdev_priv(dev);
	struct sk_buff *skb;
	struct archdr *pkt = pkthdr;
	char pktbuf, pkthdrbuf;
	int ofs;

	arc_printk(D_DURING, dev, "it's a raw(cap) packet (length=%d)\n",
	length);

	if (length >= MinTU)
	ofs = 512 - length;
	else
	ofs = 256 - length;

	skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
	if (!skb) {
	dev->stats.rx_dropped++;
	return;
	}
	skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
	skb->dev = dev;
	skb_reset_mac_header(skb);
	pkt = (struct archdr *)skb_mac_header(skb);
	skb_pull(skb, ARC_HDR_SIZE);

	/* up to sizeof(pkt->soft) has already been copied from the card
	* squeeze in an int for the cap encapsulation
	* use these variables to be sure we count in bytes, not in
	* sizeof(struct archdr)
	*/
	pktbuf = (char *)pkt;
	pkthdrbuf = (char *)pkthdr;
	memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto));
	memcpy(pktbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto) + sizeof(int),
	pkthdrbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto),
	sizeof(struct archdr) - ARC_HDR_SIZE - sizeof(pkt->soft.cap.proto));

	if (length > sizeof(pkt->soft))
	lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
	pkt->soft.raw + sizeof(pkt->soft)
	+ sizeof(int),
	length - sizeof(pkt->soft));

	if (BUGLVL(D_SKB))
	arcnet_dump_skb(dev, skb, "rx");

	skb->protocol = cpu_to_be16(ETH_P_ARCNET);
	netif_rx(skb);
	}

	/* Create the ARCnet hard/soft headers for cap mode.
	* There aren't any soft headers in cap mode - not even the protocol id.
	*/
	static int build_header(struct sk_buff *skb,
	struct net_device *dev,
	unsigned short type,
	uint8_t daddr)
	{
	int hdr_size = ARC_HDR_SIZE;
	struct archdr pkt = (struct archdr )skb_push(skb, hdr_size);

	arc_printk(D_PROTO, dev, "Preparing header for cap packet %x.\n",
	((int )&pkt->soft.cap.cookie[0]));

	/* Set the source hardware address.
	*
	* This is pretty pointless for most purposes, but it can help in
	* debugging. ARCnet does not allow us to change the source address in
	* the actual packet sent)
	*/
	pkt->hard.source = *dev->dev_addr;

	/* see linux/net/ethernet/eth.c to see where I got the following */

	if (dev->flags & (IFF_LOOPBACK \| IFF_NOARP)) {
	/* FIXME: fill in the last byte of the dest ipaddr here to
	* better comply with RFC1051 in "noarp" mode.
	*/
	pkt->hard.dest = 0;
	return hdr_size;
	}
	/* otherwise, just fill it in and go! */
	pkt->hard.dest = daddr;

	return hdr_size; /* success */
	}

	static int prepare_tx(struct net_device dev, struct archdr pkt, int length,
	int bufnum)
	{
	struct arcnet_local *lp = netdev_priv(dev);
	struct arc_hardware *hard = &pkt->hard;
	int ofs;

	/* hard header is not included in packet length */
	length -= ARC_HDR_SIZE;
	/* And neither is the cookie field */
	length -= sizeof(int);

	arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
	lp->next_tx, lp->cur_tx, bufnum);

	arc_printk(D_PROTO, dev, "Sending for cap packet %x.\n",
	((int )&pkt->soft.cap.cookie[0]));

	if (length > XMTU) {
	/* should never happen! other people already check for this. */
	arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n",
	length, XMTU);
	length = XMTU;
	}
	if (length > MinTU) {
	hard->offset[0] = 0;
	hard->offset[1] = ofs = 512 - length;
	} else if (length > MTU) {
	hard->offset[0] = 0;
	hard->offset[1] = ofs = 512 - length - 3;
	} else {
	hard->offset[0] = ofs = 256 - length;
	}

	arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n",
	length, ofs);

	/* Copy the arcnet-header + the protocol byte down: */
	lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
	lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
	sizeof(pkt->soft.cap.proto));

	/* Skip the extra integer we have written into it as a cookie
	* but write the rest of the message:
	*/
	lp->hw.copy_to_card(dev, bufnum, ofs + 1,
	((unsigned char *)&pkt->soft.cap.mes), length - 1);

	lp->lastload_dest = hard->dest;

	return 1; /* done */
	}

	static int ack_tx(struct net_device *dev, int acked)
	{
	struct arcnet_local *lp = netdev_priv(dev);
	struct sk_buff *ackskb;
	struct archdr *ackpkt;
	int length = sizeof(struct arc_cap);

	arc_printk(D_DURING, dev, "capmode: ack_tx: protocol: %x: result: %d\n",
	lp->outgoing.skb->protocol, acked);

	if (BUGLVL(D_SKB))
	arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");

	/* Now alloc a skb to send back up through the layers: */
	ackskb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
	if (!ackskb)
	goto free_outskb;

	skb_put(ackskb, length + ARC_HDR_SIZE);
	ackskb->dev = dev;

	skb_reset_mac_header(ackskb);
	ackpkt = (struct archdr *)skb_mac_header(ackskb);
	/* skb_pull(ackskb, ARC_HDR_SIZE); */

	skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
	ARC_HDR_SIZE + sizeof(struct arc_cap));
	ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
	ackpkt->soft.cap.mes.ack = acked;

	arc_printk(D_PROTO, dev, "Ackknowledge for cap packet %x.\n",
	((int )&ackpkt->soft.cap.cookie[0]));

	ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);

	if (BUGLVL(D_SKB))
	arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
	netif_rx(ackskb);

	free_outskb:
	dev_kfree_skb_irq(lp->outgoing.skb);
	lp->outgoing.proto = NULL;
	/* We are always finished when in this protocol */

	return 0;
	}

	static struct ArcProto capmode_proto = {
	.suffix = 'r',
	.mtu = XMTU,
	.rx = rx,
	.build_header = build_header,
	.prepare_tx = prepare_tx,
	.ack_tx = ack_tx
	};

	static int __init capmode_module_init(void)
	{
	int count;

	pr_info("cap mode (`c') encapsulation support loaded\n");

	for (count = 1; count <= 8; count++)
	if (arc_proto_map[count] == arc_proto_default)
	arc_proto_map[count] = &capmode_proto;

	/* for cap mode, we only set the bcast proto if there's no better one */
	if (arc_bcast_proto == arc_proto_default)
	arc_bcast_proto = &capmode_proto;

	arc_proto_default = &capmode_proto;
	arc_raw_proto = &capmode_proto;

	return 0;
	}

	static void __exit capmode_module_exit(void)
	{
	arcnet_unregister_proto(&capmode_proto);
	}
	module_init(capmode_module_init);
	module_exit(capmode_module_exit);

	MODULE_LICENSE("GPL");