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/gfp.h>
  31 #include <linux/init.h>
  32 #include <linux/if_arp.h>
  33 #include <net/arp.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/arcdevice.h>
  37
  38 #define VERSION "arcnet: cap mode (`c') encapsulation support loaded.\n"
  39
  40 /* packet receiver */
  41 static void rx(struct net_device *dev, int bufnum,
  42                struct archdr *pkthdr, int length)
  43 {
  44         struct arcnet_local *lp = netdev_priv(dev);
  45         struct sk_buff *skb;
  46         struct archdr *pkt = pkthdr;
  47         char *pktbuf, *pkthdrbuf;
  48         int ofs;
  49
  50         BUGMSG(D_DURING, "it's a raw(cap) packet (length=%d)\n", length);
  51
  52         if (length >= MinTU)
  53                 ofs = 512 - length;
  54         else
  55                 ofs = 256 - length;
  56
  57         skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
  58         if (skb == NULL) {
  59                 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
  60                 dev->stats.rx_dropped++;
  61                 return;
  62         }
  63         skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
  64         skb->dev = dev;
  65         skb_reset_mac_header(skb);
  66         pkt = (struct archdr *)skb_mac_header(skb);
  67         skb_pull(skb, ARC_HDR_SIZE);
  68
  69         /* up to sizeof(pkt->soft) has already been copied from the card */
  70         /* squeeze in an int for the cap encapsulation */
  71
  72         /* use these variables to be sure we count in bytes, not in
  73            sizeof(struct archdr) */
  74         pktbuf=(char*)pkt;
  75         pkthdrbuf=(char*)pkthdr;
  76         memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto));
  77         memcpy(pktbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto)+sizeof(int),
  78                pkthdrbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto),
  79                sizeof(struct archdr)-ARC_HDR_SIZE-sizeof(pkt->soft.cap.proto));
  80
  81         if (length > sizeof(pkt->soft))
  82                 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
  83                                       pkt->soft.raw + sizeof(pkt->soft)
  84                                       + sizeof(int),
  85                                       length - sizeof(pkt->soft));
  86
  87         BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
  88
  89         skb->protocol = cpu_to_be16(ETH_P_ARCNET);
  90         netif_rx(skb);
  91 }
  92
  93
  94 /*
  95  * Create the ARCnet hard/soft headers for cap mode.
  96  * There aren't any soft headers in cap mode - not even the protocol id.
  97  */
  98 static int build_header(struct sk_buff *skb,
  99                         struct net_device *dev,
 100                         unsigned short type,
 101                         uint8_t daddr)
 102 {
 103         int hdr_size = ARC_HDR_SIZE;
 104         struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
 105
 106         BUGMSG(D_PROTO, "Preparing header for cap packet %x.\n",
 107                *((int*)&pkt->soft.cap.cookie[0]));
 108         /*
 109          * Set the source hardware address.
 110          *
 111          * This is pretty pointless for most purposes, but it can help in
 112          * debugging.  ARCnet does not allow us to change the source address in
 113          * the actual packet sent)
 114          */
 115         pkt->hard.source = *dev->dev_addr;
 116
 117         /* see linux/net/ethernet/eth.c to see where I got the following */
 118
 119         if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
 120                 /*
 121                  * FIXME: fill in the last byte of the dest ipaddr here to better
 122                  * comply with RFC1051 in "noarp" mode.
 123                  */
 124                 pkt->hard.dest = 0;
 125                 return hdr_size;
 126         }
 127         /* otherwise, just fill it in and go! */
 128         pkt->hard.dest = daddr;
 129
 130         return hdr_size;        /* success */
 131 }
 132
 133
 134 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
 135                       int bufnum)
 136 {
 137         struct arcnet_local *lp = netdev_priv(dev);
 138         struct arc_hardware *hard = &pkt->hard;
 139         int ofs;
 140
 141
 142         /* hard header is not included in packet length */
 143         length -= ARC_HDR_SIZE;
 144         /* And neither is the cookie field */
 145         length -= sizeof(int);
 146
 147         BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
 148                lp->next_tx, lp->cur_tx, bufnum);
 149
 150         BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
 151                *((int*)&pkt->soft.cap.cookie[0]));
 152
 153         if (length > XMTU) {
 154                 /* should never happen! other people already check for this. */
 155                 BUGMSG(D_NORMAL, "Bug!  prepare_tx with size %d (> %d)\n",
 156                        length, XMTU);
 157                 length = XMTU;
 158         }
 159         if (length > MinTU) {
 160                 hard->offset[0] = 0;
 161                 hard->offset[1] = ofs = 512 - length;
 162         } else if (length > MTU) {
 163                 hard->offset[0] = 0;
 164                 hard->offset[1] = ofs = 512 - length - 3;
 165         } else
 166                 hard->offset[0] = ofs = 256 - length;
 167
 168         BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n",
 169                length,ofs);
 170
 171         /* Copy the arcnet-header + the protocol byte down: */
 172         lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
 173         lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
 174                             sizeof(pkt->soft.cap.proto));
 175
 176         /* Skip the extra integer we have written into it as a cookie
 177            but write the rest of the message: */
 178         lp->hw.copy_to_card(dev, bufnum, ofs+1,
 179                             ((unsigned char*)&pkt->soft.cap.mes),length-1);
 180
 181         lp->lastload_dest = hard->dest;
 182
 183         return 1;       /* done */
 184 }
 185
 186 static int ack_tx(struct net_device *dev, int acked)
 187 {
 188         struct arcnet_local *lp = netdev_priv(dev);
 189         struct sk_buff *ackskb;
 190         struct archdr *ackpkt;
 191         int length=sizeof(struct arc_cap);
 192
 193         BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
 194                 lp->outgoing.skb->protocol, acked);
 195
 196         BUGLVL(D_SKB) arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
 197
 198         /* Now alloc a skb to send back up through the layers: */
 199         ackskb = alloc_skb(length + ARC_HDR_SIZE , GFP_ATOMIC);
 200         if (ackskb == NULL) {
 201                 BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
 202                 goto free_outskb;
 203         }
 204
 205         skb_put(ackskb, length + ARC_HDR_SIZE );
 206         ackskb->dev = dev;
 207
 208         skb_reset_mac_header(ackskb);
 209         ackpkt = (struct archdr *)skb_mac_header(ackskb);
 210         /* skb_pull(ackskb, ARC_HDR_SIZE); */
 211
 212         skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
 213                                   ARC_HDR_SIZE + sizeof(struct arc_cap));
 214         ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
 215         ackpkt->soft.cap.mes.ack=acked;
 216
 217         BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
 218                         *((int*)&ackpkt->soft.cap.cookie[0]));
 219
 220         ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);
 221
 222         BUGLVL(D_SKB) arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
 223         netif_rx(ackskb);
 224
 225 free_outskb:
 226         dev_kfree_skb_irq(lp->outgoing.skb);
 227         lp->outgoing.proto = NULL; /* We are always finished when in this protocol */
 228
 229         return 0;
 230 }
 231
 232 static struct ArcProto capmode_proto =
 233 {
 234         'r',
 235         XMTU,
 236         0,
 237         rx,
 238         build_header,
 239         prepare_tx,
 240         NULL,
 241         ack_tx
 242 };
 243
 244 static void arcnet_cap_init(void)
 245 {
 246         int count;
 247
 248         for (count = 1; count <= 8; count++)
 249                 if (arc_proto_map[count] == arc_proto_default)
 250                         arc_proto_map[count] = &capmode_proto;
 251
 252         /* for cap mode, we only set the bcast proto if there's no better one */
 253         if (arc_bcast_proto == arc_proto_default)
 254                 arc_bcast_proto = &capmode_proto;
 255
 256         arc_proto_default = &capmode_proto;
 257         arc_raw_proto = &capmode_proto;
 258 }
 259
 260 static int __init capmode_module_init(void)
 261 {
 262         printk(VERSION);
 263         arcnet_cap_init();
 264         return 0;
 265 }
 266
 267 static void __exit capmode_module_exit(void)
 268 {
 269         arcnet_unregister_proto(&capmode_proto);
 270 }
 271 module_init(capmode_module_init);
 272 module_exit(capmode_module_exit);
 273
 274 MODULE_LICENSE("GPL");