1/* 2 * Linux ARCnet driver - RFC1051 ("simple" standard) packet encapsulation 3 * 4 * Written 1994-1999 by Avery Pennarun. 5 * Derived from skeleton.c by Donald Becker. 6 * 7 * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com) 8 * for sponsoring the further development of this driver. 9 * 10 * ********************** 11 * 12 * The original copyright of skeleton.c was as follows: 13 * 14 * skeleton.c Written 1993 by Donald Becker. 15 * Copyright 1993 United States Government as represented by the 16 * Director, National Security Agency. This software may only be used 17 * and distributed according to the terms of the GNU General Public License as 18 * modified by SRC, incorporated herein by reference. 19 * 20 * ********************** 21 * 22 * For more details, see drivers/net/arcnet.c 23 * 24 * ********************** 25 */ 26#include <linux/module.h> 27#include <linux/init.h> 28#include <linux/if_arp.h> 29#include <net/arp.h> 30#include <linux/netdevice.h> 31#include <linux/skbuff.h> 32#include <linux/arcdevice.h> 33 34#define VERSION "arcnet: RFC1051 \"simple standard\" (`s') encapsulation support loaded.\n" 35 36 37static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev); 38static void rx(struct net_device *dev, int bufnum, 39 struct archdr *pkthdr, int length); 40static int build_header(struct sk_buff *skb, struct net_device *dev, 41 unsigned short type, uint8_t daddr); 42static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 43 int bufnum); 44 45 46static struct ArcProto rfc1051_proto = 47{ 48 .suffix = 's', 49 .mtu = XMTU - RFC1051_HDR_SIZE, 50 .is_ip = 1, 51 .rx = rx, 52 .build_header = build_header, 53 .prepare_tx = prepare_tx, 54 .continue_tx = NULL, 55 .ack_tx = NULL 56}; 57 58 59static int __init arcnet_rfc1051_init(void) 60{ 61 printk(VERSION); 62 63 arc_proto_map[ARC_P_IP_RFC1051] 64 = arc_proto_map[ARC_P_ARP_RFC1051] 65 = &rfc1051_proto; 66 67 /* if someone else already owns the broadcast, we won't take it */ 68 if (arc_bcast_proto == arc_proto_default) 69 arc_bcast_proto = &rfc1051_proto; 70 71 return 0; 72} 73 74static void __exit arcnet_rfc1051_exit(void) 75{ 76 arcnet_unregister_proto(&rfc1051_proto); 77} 78 79module_init(arcnet_rfc1051_init); 80module_exit(arcnet_rfc1051_exit); 81 82MODULE_LICENSE("GPL"); 83 84/* 85 * Determine a packet's protocol ID. 86 * 87 * With ARCnet we have to convert everything to Ethernet-style stuff. 88 */ 89static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev) 90{ 91 struct arcnet_local *lp = dev->priv; 92 struct archdr *pkt = (struct archdr *) skb->data; 93 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 94 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 95 96 /* Pull off the arcnet header. */ 97 skb_reset_mac_header(skb); 98 skb_pull(skb, hdr_size); 99 100 if (pkt->hard.dest == 0) 101 skb->pkt_type = PACKET_BROADCAST; 102 else if (dev->flags & IFF_PROMISC) { 103 /* if we're not sending to ourselves :) */ 104 if (pkt->hard.dest != dev->dev_addr[0]) 105 skb->pkt_type = PACKET_OTHERHOST; 106 } 107 /* now return the protocol number */ 108 switch (soft->proto) { 109 case ARC_P_IP_RFC1051: 110 return htons(ETH_P_IP); 111 case ARC_P_ARP_RFC1051: 112 return htons(ETH_P_ARP); 113 114 default: 115 lp->stats.rx_errors++; 116 lp->stats.rx_crc_errors++; 117 return 0; 118 } 119 120 return htons(ETH_P_IP); 121} 122 123 124/* packet receiver */ 125static void rx(struct net_device *dev, int bufnum, 126 struct archdr *pkthdr, int length) 127{ 128 struct arcnet_local *lp = dev->priv; 129 struct sk_buff *skb; 130 struct archdr *pkt = pkthdr; 131 int ofs; 132 133 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length); 134 135 if (length >= MinTU) 136 ofs = 512 - length; 137 else 138 ofs = 256 - length; 139 140 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 141 if (skb == NULL) { 142 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n"); 143 lp->stats.rx_dropped++; 144 return; 145 } 146 skb_put(skb, length + ARC_HDR_SIZE); 147 skb->dev = dev; 148 149 pkt = (struct archdr *) skb->data; 150 151 /* up to sizeof(pkt->soft) has already been copied from the card */ 152 memcpy(pkt, pkthdr, sizeof(struct archdr)); 153 if (length > sizeof(pkt->soft)) 154 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 155 pkt->soft.raw + sizeof(pkt->soft), 156 length - sizeof(pkt->soft)); 157 158 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx"); 159 160 skb->protocol = type_trans(skb, dev); 161 netif_rx(skb); 162 dev->last_rx = jiffies; 163} 164 165 166/* 167 * Create the ARCnet hard/soft headers for RFC1051. 168 */ 169static int build_header(struct sk_buff *skb, struct net_device *dev, 170 unsigned short type, uint8_t daddr) 171{ 172 struct arcnet_local *lp = dev->priv; 173 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 174 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size); 175 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 176 177 /* set the protocol ID according to RFC1051 */ 178 switch (type) { 179 case ETH_P_IP: 180 soft->proto = ARC_P_IP_RFC1051; 181 break; 182 case ETH_P_ARP: 183 soft->proto = ARC_P_ARP_RFC1051; 184 break; 185 default: 186 BUGMSG(D_NORMAL, "RFC1051: I don't understand protocol %d (%Xh)\n", 187 type, type); 188 lp->stats.tx_errors++; 189 lp->stats.tx_aborted_errors++; 190 return 0; 191 } 192 193 194 /* 195 * Set the source hardware address. 196 * 197 * This is pretty pointless for most purposes, but it can help in 198 * debugging. ARCnet does not allow us to change the source address in 199 * the actual packet sent) 200 */ 201 pkt->hard.source = *dev->dev_addr; 202 203 /* see linux/net/ethernet/eth.c to see where I got the following */ 204 205 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 206 pkt->hard.dest = 0; 207 return hdr_size; 208 } 209 /* otherwise, just fill it in and go! */ 210 pkt->hard.dest = daddr; 211 212 return hdr_size; /* success */ 213} 214 215 216static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 217 int bufnum) 218{ 219 struct arcnet_local *lp = dev->priv; 220 struct arc_hardware *hard = &pkt->hard; 221 int ofs; 222 223 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n", 224 lp->next_tx, lp->cur_tx, bufnum); 225 226 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */ 227 228 if (length > XMTU) { 229 /* should never happen! other people already check for this. */ 230 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n", 231 length, XMTU); 232 length = XMTU; 233 } 234 if (length > MinTU) { 235 hard->offset[0] = 0; 236 hard->offset[1] = ofs = 512 - length; 237 } else if (length > MTU) { 238 hard->offset[0] = 0; 239 hard->offset[1] = ofs = 512 - length - 3; 240 } else 241 hard->offset[0] = ofs = 256 - length; 242 243 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 244 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 245 246 lp->lastload_dest = hard->dest; 247 248 return 1; /* done */ 249} 250