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linux/drivers/net/arcnet/capmode.c

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/*
* 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
*
* **********************
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/if_arp.h>
#include <net/arp.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/arcdevice.h>
#define VERSION "arcnet: cap mode (`c') encapsulation support loaded.\n"
static void rx(struct net_device *dev, int bufnum,
struct archdr *pkthdr, int length);
static int build_header(struct sk_buff *skb,
struct net_device *dev,
unsigned short type,
uint8_t daddr);
static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
int bufnum);
static int ack_tx(struct net_device *dev, int acked);
static struct ArcProto capmode_proto =
{
'r',
XMTU,
0,
rx,
build_header,
prepare_tx,
NULL,
ack_tx
};
void arcnet_cap_init(void)
{
int count;
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;
}
#ifdef MODULE
static int __init capmode_module_init(void)
{
printk(VERSION);
arcnet_cap_init();
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");
#endif /* MODULE */
/* 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;
BUGMSG(D_DURING, "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 == NULL) {
BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
lp->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));
BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
skb->protocol = __constant_htons(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);
BUGMSG(D_PROTO, "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);
BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
lp->next_tx, lp->cur_tx, bufnum);
BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
*((int*)&pkt->soft.cap.cookie[0]));
if (length > XMTU) {
/* should never happen! other people already check for this. */
BUGMSG(D_NORMAL, "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;
BUGMSG(D_DURING, "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);
BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
lp->outgoing.skb->protocol, acked);
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 == NULL) {
BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
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;
BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
*((int*)&ackpkt->soft.cap.cookie[0]));
ackskb->protocol = __constant_htons(ETH_P_ARCNET);
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;
}
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