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 #define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt 30 31 #include <linux/module.h> 32 #include <linux/gfp.h> 33 #include <linux/init.h> 34 #include <linux/if_arp.h> 35 #include <net/arp.h> 36 #include <linux/netdevice.h> 37 #include <linux/skbuff.h> 38 39 #include "arcdevice.h" 40 41 /* packet receiver */ 42 static void rx(struct net_device *dev, int bufnum, 43 struct archdr *pkthdr, int length) 44 { 45 struct arcnet_local *lp = netdev_priv(dev); 46 struct sk_buff *skb; 47 struct archdr *pkt; 48 char *pktbuf, *pkthdrbuf; 49 int ofs; 50 51 arc_printk(D_DURING, dev, "it's a raw(cap) packet (length=%d)\n", 52 length); 53 54 if (length >= MinTU) 55 ofs = 512 - length; 56 else 57 ofs = 256 - length; 58 59 skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC); 60 if (!skb) { 61 dev->stats.rx_dropped++; 62 return; 63 } 64 skb_put(skb, length + ARC_HDR_SIZE + sizeof(int)); 65 skb->dev = dev; 66 skb_reset_mac_header(skb); 67 pkt = (struct archdr *)skb_mac_header(skb); 68 skb_pull(skb, ARC_HDR_SIZE); 69 70 /* up to sizeof(pkt->soft) has already been copied from the card 71 * squeeze in an int for the cap encapsulation 72 * use these variables to be sure we count in bytes, not in 73 * sizeof(struct archdr) 74 */ 75 pktbuf = (char *)pkt; 76 pkthdrbuf = (char *)pkthdr; 77 memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto)); 78 memcpy(pktbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto) + sizeof(int), 79 pkthdrbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto), 80 sizeof(struct archdr) - ARC_HDR_SIZE - sizeof(pkt->soft.cap.proto)); 81 82 if (length > sizeof(pkt->soft)) 83 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 84 pkt->soft.raw + sizeof(pkt->soft) 85 + sizeof(int), 86 length - sizeof(pkt->soft)); 87 88 if (BUGLVL(D_SKB)) 89 arcnet_dump_skb(dev, skb, "rx"); 90 91 skb->protocol = cpu_to_be16(ETH_P_ARCNET); 92 netif_rx(skb); 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 = skb_push(skb, hdr_size); 105 106 arc_printk(D_PROTO, dev, "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 /* FIXME: fill in the last byte of the dest ipaddr here to 121 * better comply with RFC1051 in "noarp" mode. 122 */ 123 pkt->hard.dest = 0; 124 return hdr_size; 125 } 126 /* otherwise, just fill it in and go! */ 127 pkt->hard.dest = daddr; 128 129 return hdr_size; /* success */ 130 } 131 132 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 133 int bufnum) 134 { 135 struct arcnet_local *lp = netdev_priv(dev); 136 struct arc_hardware *hard = &pkt->hard; 137 int ofs; 138 139 /* hard header is not included in packet length */ 140 length -= ARC_HDR_SIZE; 141 /* And neither is the cookie field */ 142 length -= sizeof(int); 143 144 arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n", 145 lp->next_tx, lp->cur_tx, bufnum); 146 147 arc_printk(D_PROTO, dev, "Sending for cap packet %x.\n", 148 *((int *)&pkt->soft.cap.cookie[0])); 149 150 if (length > XMTU) { 151 /* should never happen! other people already check for this. */ 152 arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n", 153 length, XMTU); 154 length = XMTU; 155 } 156 if (length > MinTU) { 157 hard->offset[0] = 0; 158 hard->offset[1] = ofs = 512 - length; 159 } else if (length > MTU) { 160 hard->offset[0] = 0; 161 hard->offset[1] = ofs = 512 - length - 3; 162 } else { 163 hard->offset[0] = ofs = 256 - length; 164 } 165 166 arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n", 167 length, ofs); 168 169 /* Copy the arcnet-header + the protocol byte down: */ 170 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 171 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto, 172 sizeof(pkt->soft.cap.proto)); 173 174 /* Skip the extra integer we have written into it as a cookie 175 * but write the rest of the message: 176 */ 177 lp->hw.copy_to_card(dev, bufnum, ofs + 1, 178 ((unsigned char *)&pkt->soft.cap.mes), length - 1); 179 180 lp->lastload_dest = hard->dest; 181 182 return 1; /* done */ 183 } 184 185 static int ack_tx(struct net_device *dev, int acked) 186 { 187 struct arcnet_local *lp = netdev_priv(dev); 188 struct sk_buff *ackskb; 189 struct archdr *ackpkt; 190 int length = sizeof(struct arc_cap); 191 192 arc_printk(D_DURING, dev, "capmode: ack_tx: protocol: %x: result: %d\n", 193 lp->outgoing.skb->protocol, acked); 194 195 if (BUGLVL(D_SKB)) 196 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) 201 goto free_outskb; 202 203 skb_put(ackskb, length + ARC_HDR_SIZE); 204 ackskb->dev = dev; 205 206 skb_reset_mac_header(ackskb); 207 ackpkt = (struct archdr *)skb_mac_header(ackskb); 208 /* skb_pull(ackskb, ARC_HDR_SIZE); */ 209 210 skb_copy_from_linear_data(lp->outgoing.skb, ackpkt, 211 ARC_HDR_SIZE + sizeof(struct arc_cap)); 212 ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */ 213 ackpkt->soft.cap.mes.ack = acked; 214 215 arc_printk(D_PROTO, dev, "Acknowledge for cap packet %x.\n", 216 *((int *)&ackpkt->soft.cap.cookie[0])); 217 218 ackskb->protocol = cpu_to_be16(ETH_P_ARCNET); 219 220 if (BUGLVL(D_SKB)) 221 arcnet_dump_skb(dev, ackskb, "ack_tx_recv"); 222 netif_rx(ackskb); 223 224 free_outskb: 225 dev_kfree_skb_irq(lp->outgoing.skb); 226 lp->outgoing.proto = NULL; 227 /* We are always finished when in this protocol */ 228 229 return 0; 230 } 231 232 static struct ArcProto capmode_proto = { 233 .suffix = 'r', 234 .mtu = XMTU, 235 .rx = rx, 236 .build_header = build_header, 237 .prepare_tx = prepare_tx, 238 .ack_tx = ack_tx 239 }; 240 241 static int __init capmode_module_init(void) 242 { 243 int count; 244 245 pr_info("cap mode (`c') encapsulation support loaded\n"); 246 247 for (count = 1; count <= 8; count++) 248 if (arc_proto_map[count] == arc_proto_default) 249 arc_proto_map[count] = &capmode_proto; 250 251 /* for cap mode, we only set the bcast proto if there's no better one */ 252 if (arc_bcast_proto == arc_proto_default) 253 arc_bcast_proto = &capmode_proto; 254 255 arc_proto_default = &capmode_proto; 256 arc_raw_proto = &capmode_proto; 257 258 return 0; 259 } 260 261 static void __exit capmode_module_exit(void) 262 { 263 arcnet_unregister_proto(&capmode_proto); 264 } 265 module_init(capmode_module_init); 266 module_exit(capmode_module_exit); 267 268 MODULE_LICENSE("GPL"); 269