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aha/drivers/net/arcnet/rfc1201.c
Al Viro 701181ac1d arcnet endianness annotations 
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-10-10 16:51:59 -07:00

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/*
* Linux ARCnet driver - RFC1201 (standard) packet encapsulation
*
* Written 1994-1999 by Avery Pennarun.
* Derived from skeleton.c by Donald Becker.
*
* Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
* for sponsoring the further development of this driver.
*
* **********************
*
* 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 <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/arcdevice.h>
MODULE_LICENSE("GPL");
#define VERSION "arcnet: RFC1201 \"standard\" (`a') encapsulation support loaded.\n"
static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
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 continue_tx(struct net_device *dev, int bufnum);
static struct ArcProto rfc1201_proto =
{
.suffix = 'a',
.mtu = 1500, /* could be more, but some receivers can't handle it... */
.is_ip = 1, /* This is for sending IP and ARP packages */
.rx = rx,
.build_header = build_header,
.prepare_tx = prepare_tx,
.continue_tx = continue_tx,
.ack_tx = NULL
};
static int __init arcnet_rfc1201_init(void)
{
printk(VERSION);
arc_proto_map[ARC_P_IP]
= arc_proto_map[ARC_P_IPV6]
= arc_proto_map[ARC_P_ARP]
= arc_proto_map[ARC_P_RARP]
= arc_proto_map[ARC_P_IPX]
= arc_proto_map[ARC_P_NOVELL_EC]
= &rfc1201_proto;
/* if someone else already owns the broadcast, we won't take it */
if (arc_bcast_proto == arc_proto_default)
arc_bcast_proto = &rfc1201_proto;
return 0;
}
static void __exit arcnet_rfc1201_exit(void)
{
arcnet_unregister_proto(&rfc1201_proto);
}
module_init(arcnet_rfc1201_init);
module_exit(arcnet_rfc1201_exit);
/*
* Determine a packet's protocol ID.
*
* With ARCnet we have to convert everything to Ethernet-style stuff.
*/
static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
{
struct archdr *pkt = (struct archdr *) skb->data;
struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
struct arcnet_local *lp = dev->priv;
int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
/* Pull off the arcnet header. */
skb_reset_mac_header(skb);
skb_pull(skb, hdr_size);
if (pkt->hard.dest == 0)
skb->pkt_type = PACKET_BROADCAST;
else if (dev->flags & IFF_PROMISC) {
/* if we're not sending to ourselves :) */
if (pkt->hard.dest != dev->dev_addr[0])
skb->pkt_type = PACKET_OTHERHOST;
}
/* now return the protocol number */
switch (soft->proto) {
case ARC_P_IP:
return htons(ETH_P_IP);
case ARC_P_IPV6:
return htons(ETH_P_IPV6);
case ARC_P_ARP:
return htons(ETH_P_ARP);
case ARC_P_RARP:
return htons(ETH_P_RARP);
case ARC_P_IPX:
case ARC_P_NOVELL_EC:
return htons(ETH_P_802_3);
default:
lp->stats.rx_errors++;
lp->stats.rx_crc_errors++;
return 0;
}
return htons(ETH_P_IP);
}
/* packet receiver */
static void rx(struct net_device *dev, int bufnum,
struct archdr *pkthdr, int length)
{
struct arcnet_local *lp = dev->priv;
struct sk_buff *skb;
struct archdr *pkt = pkthdr;
struct arc_rfc1201 *soft = &pkthdr->soft.rfc1201;
int saddr = pkt->hard.source, ofs;
struct Incoming *in = &lp->rfc1201.incoming[saddr];
BUGMSG(D_DURING, "it's an RFC1201 packet (length=%d)\n", length);
if (length >= MinTU)
ofs = 512 - length;
else
ofs = 256 - length;
if (soft->split_flag == 0xFF) { /* Exception Packet */
if (length >= 4 + RFC1201_HDR_SIZE)
BUGMSG(D_DURING, "compensating for exception packet\n");
else {
BUGMSG(D_EXTRA, "short RFC1201 exception packet from %02Xh",
saddr);
return;
}
/* skip over 4-byte junkola */
length -= 4;
ofs += 4;
lp->hw.copy_from_card(dev, bufnum, 512 - length,
soft, sizeof(pkt->soft));
}
if (!soft->split_flag) { /* not split */
BUGMSG(D_RX, "incoming is not split (splitflag=%d)\n",
soft->split_flag);
if (in->skb) { /* already assembling one! */
BUGMSG(D_EXTRA, "aborting assembly (seq=%d) for unsplit packet (splitflag=%d, seq=%d)\n",
in->sequence, soft->split_flag, soft->sequence);
lp->rfc1201.aborted_seq = soft->sequence;
dev_kfree_skb_irq(in->skb);
lp->stats.rx_errors++;
lp->stats.rx_missed_errors++;
in->skb = NULL;
}
in->sequence = soft->sequence;
skb = alloc_skb(length + ARC_HDR_SIZE, 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);
skb->dev = dev;
pkt = (struct archdr *) skb->data;
soft = &pkt->soft.rfc1201;
/* up to sizeof(pkt->soft) has already been copied from the card */
memcpy(pkt, pkthdr, sizeof(struct archdr));
if (length > sizeof(pkt->soft))
lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
pkt->soft.raw + sizeof(pkt->soft),
length - sizeof(pkt->soft));
/*
* ARP packets have problems when sent from some DOS systems: the
* source address is always 0! So we take the hardware source addr
* (which is impossible to fumble) and insert it ourselves.
*/
if (soft->proto == ARC_P_ARP) {
struct arphdr *arp = (struct arphdr *) soft->payload;
/* make sure addresses are the right length */
if (arp->ar_hln == 1 && arp->ar_pln == 4) {
uint8_t *cptr = (uint8_t *) arp + sizeof(struct arphdr);
if (!*cptr) { /* is saddr = 00? */
BUGMSG(D_EXTRA,
"ARP source address was 00h, set to %02Xh.\n",
saddr);
lp->stats.rx_crc_errors++;
*cptr = saddr;
} else {
BUGMSG(D_DURING, "ARP source address (%Xh) is fine.\n",
*cptr);
}
} else {
BUGMSG(D_NORMAL, "funny-shaped ARP packet. (%Xh, %Xh)\n",
arp->ar_hln, arp->ar_pln);
lp->stats.rx_errors++;
lp->stats.rx_crc_errors++;
}
}
BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
skb->protocol = type_trans(skb, dev);
netif_rx(skb);
dev->last_rx = jiffies;
} else { /* split packet */
/*
* NOTE: MSDOS ARP packet correction should only need to apply to
* unsplit packets, since ARP packets are so short.
*
* My interpretation of the RFC1201 document is that if a packet is
* received out of order, the entire assembly process should be
* aborted.
*
* The RFC also mentions "it is possible for successfully received
* packets to be retransmitted." As of 0.40 all previously received
* packets are allowed, not just the most recent one.
*
* We allow multiple assembly processes, one for each ARCnet card
* possible on the network. Seems rather like a waste of memory,
* but there's no other way to be reliable.
*/
BUGMSG(D_RX, "packet is split (splitflag=%d, seq=%d)\n",
soft->split_flag, in->sequence);
if (in->skb && in->sequence != soft->sequence) {
BUGMSG(D_EXTRA, "wrong seq number (saddr=%d, expected=%d, seq=%d, splitflag=%d)\n",
saddr, in->sequence, soft->sequence,
soft->split_flag);
dev_kfree_skb_irq(in->skb);
in->skb = NULL;
lp->stats.rx_errors++;
lp->stats.rx_missed_errors++;
in->lastpacket = in->numpackets = 0;
}
if (soft->split_flag & 1) { /* first packet in split */
BUGMSG(D_RX, "brand new splitpacket (splitflag=%d)\n",
soft->split_flag);
if (in->skb) { /* already assembling one! */
BUGMSG(D_EXTRA, "aborting previous (seq=%d) assembly "
"(splitflag=%d, seq=%d)\n",
in->sequence, soft->split_flag,
soft->sequence);
lp->stats.rx_errors++;
lp->stats.rx_missed_errors++;
dev_kfree_skb_irq(in->skb);
}
in->sequence = soft->sequence;
in->numpackets = ((unsigned) soft->split_flag >> 1) + 2;
in->lastpacket = 1;
if (in->numpackets > 16) {
BUGMSG(D_EXTRA, "incoming packet more than 16 segments; dropping. (splitflag=%d)\n",
soft->split_flag);
lp->rfc1201.aborted_seq = soft->sequence;
lp->stats.rx_errors++;
lp->stats.rx_length_errors++;
return;
}
in->skb = skb = alloc_skb(508 * in->numpackets + ARC_HDR_SIZE,
GFP_ATOMIC);
if (skb == NULL) {
BUGMSG(D_NORMAL, "(split) memory squeeze, dropping packet.\n");
lp->rfc1201.aborted_seq = soft->sequence;
lp->stats.rx_dropped++;
return;
}
skb->dev = dev;
pkt = (struct archdr *) skb->data;
soft = &pkt->soft.rfc1201;
memcpy(pkt, pkthdr, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
skb_put(skb, ARC_HDR_SIZE + RFC1201_HDR_SIZE);
soft->split_flag = 0; /* end result won't be split */
} else { /* not first packet */
int packetnum = ((unsigned) soft->split_flag >> 1) + 1;
/*
* if we're not assembling, there's no point trying to
* continue.
*/
if (!in->skb) {
if (lp->rfc1201.aborted_seq != soft->sequence) {
BUGMSG(D_EXTRA, "can't continue split without starting "
"first! (splitflag=%d, seq=%d, aborted=%d)\n",
soft->split_flag, soft->sequence,
lp->rfc1201.aborted_seq);
lp->stats.rx_errors++;
lp->stats.rx_missed_errors++;
}
return;
}
in->lastpacket++;
if (packetnum != in->lastpacket) { /* not the right flag! */
/* harmless duplicate? ignore. */
if (packetnum <= in->lastpacket - 1) {
BUGMSG(D_EXTRA, "duplicate splitpacket ignored! (splitflag=%d)\n",
soft->split_flag);
lp->stats.rx_errors++;
lp->stats.rx_frame_errors++;
return;
}
/* "bad" duplicate, kill reassembly */
BUGMSG(D_EXTRA, "out-of-order splitpacket, reassembly "
"(seq=%d) aborted (splitflag=%d, seq=%d)\n",
in->sequence, soft->split_flag, soft->sequence);
lp->rfc1201.aborted_seq = soft->sequence;
dev_kfree_skb_irq(in->skb);
in->skb = NULL;
lp->stats.rx_errors++;
lp->stats.rx_missed_errors++;
in->lastpacket = in->numpackets = 0;
return;
}
pkt = (struct archdr *) in->skb->data;
soft = &pkt->soft.rfc1201;
}
skb = in->skb;
lp->hw.copy_from_card(dev, bufnum, ofs + RFC1201_HDR_SIZE,
skb->data + skb->len,
length - RFC1201_HDR_SIZE);
skb_put(skb, length - RFC1201_HDR_SIZE);
/* are we done? */
if (in->lastpacket == in->numpackets) {
in->skb = NULL;
in->lastpacket = in->numpackets = 0;
BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (unsplit)\n",
skb->len, pkt->hard.source);
BUGMSG(D_SKB_SIZE, "skb: received %d bytes from %02X (split)\n",
skb->len, pkt->hard.source);
BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
skb->protocol = type_trans(skb, dev);
netif_rx(skb);
dev->last_rx = jiffies;
}
}
}
/* Create the ARCnet hard/soft headers for RFC1201. */
static int build_header(struct sk_buff *skb, struct net_device *dev,
unsigned short type, uint8_t daddr)
{
struct arcnet_local *lp = dev->priv;
int hdr_size = ARC_HDR_SIZE + RFC1201_HDR_SIZE;
struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
struct arc_rfc1201 *soft = &pkt->soft.rfc1201;
/* set the protocol ID according to RFC1201 */
switch (type) {
case ETH_P_IP:
soft->proto = ARC_P_IP;
break;
case ETH_P_IPV6:
soft->proto = ARC_P_IPV6;
break;
case ETH_P_ARP:
soft->proto = ARC_P_ARP;
break;
case ETH_P_RARP:
soft->proto = ARC_P_RARP;
break;
case ETH_P_IPX:
case ETH_P_802_3:
case ETH_P_802_2:
soft->proto = ARC_P_IPX;
break;
case ETH_P_ATALK:
soft->proto = ARC_P_ATALK;
break;
default:
BUGMSG(D_NORMAL, "RFC1201: I don't understand protocol %d (%Xh)\n",
type, type);
lp->stats.tx_errors++;
lp->stats.tx_aborted_errors++;
return 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;
soft->sequence = htons(lp->rfc1201.sequence++);
soft->split_flag = 0; /* split packets are done elsewhere */
/* 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. For now, always broadcasting
* will probably at least get packets sent out :)
*/
pkt->hard.dest = 0;
return hdr_size;
}
/* otherwise, drop in the dest address */
pkt->hard.dest = daddr;
return hdr_size;
}
static void load_pkt(struct net_device *dev, struct arc_hardware *hard,
struct arc_rfc1201 *soft, int softlen, int bufnum)
{
struct arcnet_local *lp = dev->priv;
int ofs;
/* assume length <= XMTU: someone should have handled that by now. */
if (softlen > MinTU) {
hard->offset[0] = 0;
hard->offset[1] = ofs = 512 - softlen;
} else if (softlen > MTU) { /* exception packet - add an extra header */
struct arc_rfc1201 excsoft;
excsoft.proto = soft->proto;
excsoft.split_flag = 0xff;
excsoft.sequence = htons(0xffff);
hard->offset[0] = 0;
ofs = 512 - softlen;
hard->offset[1] = ofs - RFC1201_HDR_SIZE;
lp->hw.copy_to_card(dev, bufnum, ofs - RFC1201_HDR_SIZE,
&excsoft, RFC1201_HDR_SIZE);
} else
hard->offset[0] = ofs = 256 - softlen;
lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
lp->hw.copy_to_card(dev, bufnum, ofs, soft, softlen);
lp->lastload_dest = hard->dest;
}
static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
int bufnum)
{
struct arcnet_local *lp = dev->priv;
const int maxsegsize = XMTU - RFC1201_HDR_SIZE;
struct Outgoing *out;
BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
lp->next_tx, lp->cur_tx, bufnum);
length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
pkt->soft.rfc1201.split_flag = 0;
/* need to do a split packet? */
if (length > XMTU) {
out = &lp->outgoing;
out->length = length - RFC1201_HDR_SIZE;
out->dataleft = lp->outgoing.length;
out->numsegs = (out->dataleft + maxsegsize - 1) / maxsegsize;
out->segnum = 0;
BUGMSG(D_DURING, "rfc1201 prep_tx: ready for %d-segment split "
"(%d bytes, seq=%d)\n", out->numsegs, out->length,
pkt->soft.rfc1201.sequence);
return 0; /* not done */
}
/* just load the packet into the buffers and send it off */
load_pkt(dev, &pkt->hard, &pkt->soft.rfc1201, length, bufnum);
return 1; /* done */
}
static int continue_tx(struct net_device *dev, int bufnum)
{
struct arcnet_local *lp = dev->priv;
struct Outgoing *out = &lp->outgoing;
struct arc_hardware *hard = &out->pkt->hard;
struct arc_rfc1201 *soft = &out->pkt->soft.rfc1201, *newsoft;
int maxsegsize = XMTU - RFC1201_HDR_SIZE;
int seglen;
BUGMSG(D_DURING,
"rfc1201 continue_tx: loading segment %d(+1) of %d (seq=%d)\n",
out->segnum, out->numsegs, soft->sequence);
/* the "new" soft header comes right before the data chunk */
newsoft = (struct arc_rfc1201 *)
(out->pkt->soft.raw + out->length - out->dataleft);
if (!out->segnum) /* first packet; newsoft == soft */
newsoft->split_flag = ((out->numsegs - 2) << 1) | 1;
else {
newsoft->split_flag = out->segnum << 1;
newsoft->proto = soft->proto;
newsoft->sequence = soft->sequence;
}
seglen = maxsegsize;
if (seglen > out->dataleft)
seglen = out->dataleft;
out->dataleft -= seglen;
load_pkt(dev, hard, newsoft, seglen + RFC1201_HDR_SIZE, bufnum);
out->segnum++;
if (out->segnum >= out->numsegs)
return 1;
else
return 0;
}
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