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 static 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         skb_reset_mac_header(skb);
 126         pkt = (struct archdr *)skb_mac_header(skb);
 127         skb_pull(skb, ARC_HDR_SIZE);
 128
 129         /* up to sizeof(pkt->soft) has already been copied from the card */
 130         /* squeeze in an int for the cap encapsulation */
 131
 132         /* use these variables to be sure we count in bytes, not in
 133            sizeof(struct archdr) */
 134         pktbuf=(char*)pkt;
 135         pkthdrbuf=(char*)pkthdr;
 136         memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto));
 137         memcpy(pktbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto)+sizeof(int),
 138                pkthdrbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto),
 139                sizeof(struct archdr)-ARC_HDR_SIZE-sizeof(pkt->soft.cap.proto));
 140
 141         if (length > sizeof(pkt->soft))
 142                 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
 143                                       pkt->soft.raw + sizeof(pkt->soft)
 144                                       + sizeof(int),
 145                                       length - sizeof(pkt->soft));
 146
 147         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
 148
 149         skb->protocol = __constant_htons(ETH_P_ARCNET);
 150 ;
 151         netif_rx(skb);
 152         dev->last_rx = jiffies;
 153 }
 154
 155
 156 /*
 157  * Create the ARCnet hard/soft headers for cap mode.
 158  * There aren't any soft headers in cap mode - not even the protocol id.
 159  */
 160 static int build_header(struct sk_buff *skb,
 161                         struct net_device *dev,
 162                         unsigned short type,
 163                         uint8_t daddr)
 164 {
 165         int hdr_size = ARC_HDR_SIZE;
 166         struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
 167
 168         BUGMSG(D_PROTO, "Preparing header for cap packet %x.\n",
 169                *((int*)&pkt->soft.cap.cookie[0]));
 170         /*
 171          * Set the source hardware address.
 172          *
 173          * This is pretty pointless for most purposes, but it can help in
 174          * debugging.  ARCnet does not allow us to change the source address in
 175          * the actual packet sent)
 176          */
 177         pkt->hard.source = *dev->dev_addr;
 178
 179         /* see linux/net/ethernet/eth.c to see where I got the following */
 180
 181         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 182                 /*
 183                  * FIXME: fill in the last byte of the dest ipaddr here to better
 184                  * comply with RFC1051 in "noarp" mode.
 185                  */
 186                 pkt->hard.dest = 0;
 187                 return hdr_size;
 188         }
 189         /* otherwise, just fill it in and go! */
 190         pkt->hard.dest = daddr;
 191
 192         return hdr_size;        /* success */
 193 }
 194
 195
 196 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 197                       int bufnum)
 198 {
 199         struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 200         struct arc_hardware *hard = &pkt->hard;
 201         int ofs;
 202
 203
 204         /* hard header is not included in packet length */
 205         length -= ARC_HDR_SIZE;
 206         /* And neither is the cookie field */
 207         length -= sizeof(int);
 208
 209         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 210                lp->next_tx, lp->cur_tx, bufnum);
 211
 212         BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
 213                *((int*)&pkt->soft.cap.cookie[0]));
 214
 215         if (length > XMTU) {
 216                 /* should never happen! other people already check for this. */
 217                 BUGMSG(D_NORMAL, "Bug!  prepare_tx with size %d (> %d)\n",
 218                        length, XMTU);
 219                 length = XMTU;
 220         }
 221         if (length > MinTU) {
 222                 hard->offset[0] = 0;
 223                 hard->offset[1] = ofs = 512 - length;
 224         } else if (length > MTU) {
 225                 hard->offset[0] = 0;
 226                 hard->offset[1] = ofs = 512 - length - 3;
 227         } else
 228                 hard->offset[0] = ofs = 256 - length;
 229
 230         BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n",
 231                length,ofs);
 232
 233         // Copy the arcnet-header + the protocol byte down:
 234         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 235         lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
 236                             sizeof(pkt->soft.cap.proto));
 237
 238         // Skip the extra integer we have written into it as a cookie
 239         // but write the rest of the message:
 240         lp->hw.copy_to_card(dev, bufnum, ofs+1,
 241                             ((unsigned char*)&pkt->soft.cap.mes),length-1);
 242
 243         lp->lastload_dest = hard->dest;
 244
 245         return 1;               /* done */
 246 }
 247
 248
 249 static int ack_tx(struct net_device *dev, int acked)
 250 {
 251   struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
 252   struct sk_buff *ackskb;
 253   struct archdr *ackpkt;
 254   int length=sizeof(struct arc_cap);
 255
 256   BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
 257          lp->outgoing.skb->protocol, acked);
 258
 259   BUGLVL(D_SKB) arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
 260
 261   /* Now alloc a skb to send back up through the layers: */
 262   ackskb = alloc_skb(length + ARC_HDR_SIZE , GFP_ATOMIC);
 263   if (ackskb == NULL) {
 264           BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
 265           goto free_outskb;
 266   }
 267
 268   skb_put(ackskb, length + ARC_HDR_SIZE );
 269   ackskb->dev = dev;
 270
 271   skb_reset_mac_header(ackskb);
 272   ackpkt = (struct archdr *)skb_mac_header(ackskb);
 273   /* skb_pull(ackskb, ARC_HDR_SIZE); */
 274
 275
 276   skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
 277                 ARC_HDR_SIZE + sizeof(struct arc_cap));
 278   ackpkt->soft.cap.proto=0; /* using protocol 0 for acknowledge */
 279   ackpkt->soft.cap.mes.ack=acked;
 280
 281   BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
 282          *((int*)&ackpkt->soft.cap.cookie[0]));
 283
 284   ackskb->protocol = __constant_htons(ETH_P_ARCNET);
 285
 286   BUGLVL(D_SKB) arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
 287   netif_rx(ackskb);
 288
 289  free_outskb:
 290   dev_kfree_skb_irq(lp->outgoing.skb);
 291   lp->outgoing.proto = NULL; /* We are always finished when in this protocol */
 292
 293   return 0;
 294 }