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 static 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 static int __init capmode_module_init(void) 84 { 85 printk(VERSION); 86 arcnet_cap_init(); 87 return 0; 88 } 89 90 static void __exit capmode_module_exit(void) 91 { 92 arcnet_unregister_proto(&capmode_proto); 93 } 94 module_init(capmode_module_init); 95 module_exit(capmode_module_exit); 96 97 MODULE_LICENSE("GPL"); 98 #endif /* MODULE */ 99 100 101 102 /* packet receiver */ 103 static void rx(struct net_device *dev, int bufnum, 104 struct archdr *pkthdr, int length) 105 { 106 struct arcnet_local *lp = netdev_priv(dev); 107 struct sk_buff *skb; 108 struct archdr *pkt = pkthdr; 109 char *pktbuf, *pkthdrbuf; 110 int ofs; 111 112 BUGMSG(D_DURING, "it's a raw(cap) packet (length=%d)\n", length); 113 114 if (length >= MinTU) 115 ofs = 512 - length; 116 else 117 ofs = 256 - length; 118 119 skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC); 120 if (skb == NULL) { 121 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n"); 122 dev->stats.rx_dropped++; 123 return; 124 } 125 skb_put(skb, length + ARC_HDR_SIZE + sizeof(int)); 126 skb->dev = dev; 127 skb_reset_mac_header(skb); 128 pkt = (struct archdr *)skb_mac_header(skb); 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 = cpu_to_be16(ETH_P_ARCNET); 152 netif_rx(skb); 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 = netdev_priv(dev); 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 = netdev_priv(dev); 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 = cpu_to_be16(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 } 295