drivers/net/arcnet/capmode.c

   1 /*
   2  * Linux ARCnet driver - "cap mode" packet encapsulation.
   3  * It adds sequence numbers to packets for communicating between a user space
   4  * application and the driver. After a transmit it sends a packet with protocol
   5  * byte 0 back up to the userspace containing the sequence number of the packet
   6  * plus the transmit-status on the ArcNet.
   7  *
   8  * Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
   9  * Derived from arc-rawmode.c by Avery Pennarun.
  10  * arc-rawmode was in turned based on skeleton.c, see below.
  11  *
  12  * **********************
  13  *
  14  * The original copyright of skeleton.c was as follows:
  15  *
  16  * skeleton.c Written 1993 by Donald Becker.
  17  * Copyright 1993 United States Government as represented by the
  18  * Director, National Security Agency.  This software may only be used
  19  * and distributed according to the terms of the GNU General Public License as
  20  * modified by SRC, incorporated herein by reference.
  21  *
  22  * **********************
  23  *
  24  * For more details, see drivers/net/arcnet.c
  25  *
  26  * **********************
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/if_arp.h>
  32 #include <net/arp.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/skbuff.h>
  35 #include <linux/arcdevice.h>
  36
  37 #define VERSION "arcnet: cap mode (`c') encapsulation support loaded.\n"
  38
  39
  40 static void rx(struct net_device *dev, int bufnum,
  41                struct archdr *pkthdr, int length);
  42 static int build_header(struct sk_buff *skb,
  43                         struct net_device *dev,
  44                         unsigned short type,
  45                         uint8_t daddr);
  46 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
  47                       int bufnum);
  48 static int ack_tx(struct net_device *dev, int acked);
  49
  50
  51 struct ArcProto capmode_proto =
  52 {
  53         'r',
  54         XMTU,
  55         0,
  56         rx,
  57         build_header,
  58         prepare_tx,
  59         NULL,
  60         ack_tx
  61 };
  62
  63
  64 void arcnet_cap_init(void)
  65 {
  66         int count;
  67
  68         for (count = 1; count <= 8; count++)
  69                 if (arc_proto_map[count] == arc_proto_default)
  70                         arc_proto_map[count] = &capmode_proto;
  71
  72         /* for cap mode, we only set the bcast proto if there's no better one */
  73         if (arc_bcast_proto == arc_proto_default)
  74                 arc_bcast_proto = &capmode_proto;
  75
  76         arc_proto_default = &capmode_proto;
  77         arc_raw_proto = &capmode_proto;
  78 }
  79
  80
  81 #ifdef MODULE
  82
  83 int __init init_module(void)
  84 {
  85         printk(VERSION);
  86         arcnet_cap_init();
  87         return 0;
  88 }
  89
  90 void cleanup_module(void)
  91 {
  92         arcnet_unregister_proto(&capmode_proto);
  93 }
  94
  95 MODULE_LICENSE("GPL");
  96 #endif                          /* MODULE */
  97
  98
  99
 100 /* packet receiver */
 101 static void rx(struct net_device *dev, int bufnum,
 102                struct archdr *pkthdr, int length)
 103 {
 104         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 105         struct sk_buff *skb;
 106         struct archdr *pkt = pkthdr;
 107         char *pktbuf, *pkthdrbuf;
 108         int ofs;
 109
 110         BUGMSG(D_DURING, "it's a raw(cap) packet (length=%d)\n", length);
 111
 112         if (length >= MinTU)
 113                 ofs = 512 - length;
 114         else
 115                 ofs = 256 - length;
 116
 117         skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
 118         if (skb == NULL) {
 119                 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
 120                 lp->stats.rx_dropped++;
 121                 return;
 122         }
 123         skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
 124         skb->dev = dev;
 125
 126         pkt = (struct archdr *) skb->data;
 127
 128         skb->mac.raw = skb->data;
 129         skb_pull(skb, ARC_HDR_SIZE);
 130
 131         /* up to sizeof(pkt->soft) has already been copied from the card */
 132         /* squeeze in an int for the cap encapsulation */
 133
 134         /* use these variables to be sure we count in bytes, not in
 135            sizeof(struct archdr) */
 136         pktbuf=(char*)pkt;
 137         pkthdrbuf=(char*)pkthdr;
 138         memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto));
 139         memcpy(pktbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto)+sizeof(int),
 140                pkthdrbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto),
 141                sizeof(struct archdr)-ARC_HDR_SIZE-sizeof(pkt->soft.cap.proto));
 142
 143         if (length > sizeof(pkt->soft))
 144                 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 145                                       pkt->soft.raw + sizeof(pkt->soft)
 146                                       + sizeof(int),
 147                                       length - sizeof(pkt->soft));
 148
 149         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 150
 151         skb->protocol = __constant_htons(ETH_P_ARCNET);
 152 ;
 153         netif_rx(skb);
 154         dev->last_rx = jiffies;
 155 }
 156
 157
 158 /*
 159  * Create the ARCnet hard/soft headers for cap mode.
 160  * There aren't any soft headers in cap mode - not even the protocol id.
 161  */
 162 static int build_header(struct sk_buff *skb,
 163                         struct net_device *dev,
 164                         unsigned short type,
 165                         uint8_t daddr)
 166 {
 167         int hdr_size = ARC_HDR_SIZE;
 168         struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
 169
 170         BUGMSG(D_PROTO, "Preparing header for cap packet %x.\n",
 171                *((int*)&pkt->soft.cap.cookie[0]));
 172         /*
 173          * Set the source hardware address.
 174          *
 175          * This is pretty pointless for most purposes, but it can help in
 176          * debugging.  ARCnet does not allow us to change the source address in
 177          * the actual packet sent)
 178          */
 179         pkt->hard.source = *dev->dev_addr;
 180
 181         /* see linux/net/ethernet/eth.c to see where I got the following */
 182
 183         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 184                 /*
 185                  * FIXME: fill in the last byte of the dest ipaddr here to better
 186                  * comply with RFC1051 in "noarp" mode.
 187                  */
 188                 pkt->hard.dest = 0;
 189                 return hdr_size;
 190         }
 191         /* otherwise, just fill it in and go! */
 192         pkt->hard.dest = daddr;
 193
 194         return hdr_size;        /* success */
 195 }
 196
 197
 198 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 199                       int bufnum)
 200 {
 201         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 202         struct arc_hardware *hard = &pkt->hard;
 203         int ofs;
 204
 205
 206         /* hard header is not included in packet length */
 207         length -= ARC_HDR_SIZE;
 208         /* And neither is the cookie field */
 209         length -= sizeof(int);
 210
 211         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 212                lp->next_tx, lp->cur_tx, bufnum);
 213
 214         BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
 215                *((int*)&pkt->soft.cap.cookie[0]));
 216
 217         if (length > XMTU) {
 218                 /* should never happen! other people already check for this. */
 219                 BUGMSG(D_NORMAL, "Bug!  prepare_tx with size %d (> %d)\n",
 220                        length, XMTU);
 221                 length = XMTU;
 222         }
 223         if (length > MinTU) {
 224                 hard->offset[0] = 0;
 225                 hard->offset[1] = ofs = 512 - length;
 226         } else if (length > MTU) {
 227                 hard->offset[0] = 0;
 228                 hard->offset[1] = ofs = 512 - length - 3;
 229         } else
 230                 hard->offset[0] = ofs = 256 - length;
 231
 232         BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n",
 233                length,ofs);
 234
 235         // Copy the arcnet-header + the protocol byte down:
 236         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 237         lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
 238                             sizeof(pkt->soft.cap.proto));
 239
 240         // Skip the extra integer we have written into it as a cookie
 241         // but write the rest of the message:
 242         lp->hw.copy_to_card(dev, bufnum, ofs+1,
 243                             ((unsigned char*)&pkt->soft.cap.mes),length-1);
 244
 245         lp->lastload_dest = hard->dest;
 246
 247         return 1;               /* done */
 248 }
 249
 250
 251 static int ack_tx(struct net_device *dev, int acked)
 252 {
 253   struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 254   struct sk_buff *ackskb;
 255   struct archdr *ackpkt;
 256   int length=sizeof(struct arc_cap);
 257
 258   BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
 259          lp->outgoing.skb->protocol, acked);
 260
 261   BUGLVL(D_SKB) arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
 262
 263   /* Now alloc a skb to send back up through the layers: */
 264   ackskb = alloc_skb(length + ARC_HDR_SIZE , GFP_ATOMIC);
 265   if (ackskb == NULL) {
 266           BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
 267           goto free_outskb;
 268   }
 269
 270   skb_put(ackskb, length + ARC_HDR_SIZE );
 271   ackskb->dev = dev;
 272
 273   ackpkt = (struct archdr *) ackskb->data;
 274
 275   ackskb->mac.raw = ackskb->data;
 276   /* skb_pull(ackskb, ARC_HDR_SIZE); */
 277
 278
 279   memcpy(ackpkt, lp->outgoing.skb->data, ARC_HDR_SIZE+sizeof(struct arc_cap));
 280   ackpkt->soft.cap.proto=0; /* using protocol 0 for acknowledge */
 281   ackpkt->soft.cap.mes.ack=acked;
 282
 283   BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
 284          *((int*)&ackpkt->soft.cap.cookie[0]));
 285
 286   ackskb->protocol = __constant_htons(ETH_P_ARCNET);
 287
 288   BUGLVL(D_SKB) arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
 289   netif_rx(ackskb);
 290
 291  free_outskb:
 292   dev_kfree_skb_irq(lp->outgoing.skb);
 293   lp->outgoing.proto = NULL; /* We are always finished when in this protocol */
 294
 295   return 0;
 296 }