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"); 275