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/gfp.h> 28#include <linux/init.h> 29#include <linux/if_arp.h> 30#include <net/arp.h> 31#include <linux/netdevice.h> 32#include <linux/skbuff.h> 33#include <linux/arcdevice.h> 34 35#define VERSION "arcnet: RFC1051 \"simple standard\" (`s') encapsulation support loaded.\n" 36 37 38static __be16 type_trans(struct sk_buff *skb, struct net_device *dev); 39static void rx(struct net_device *dev, int bufnum, 40 struct archdr *pkthdr, int length); 41static int build_header(struct sk_buff *skb, struct net_device *dev, 42 unsigned short type, uint8_t daddr); 43static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 44 int bufnum); 45 46 47static struct ArcProto rfc1051_proto = 48{ 49 .suffix = 's', 50 .mtu = XMTU - RFC1051_HDR_SIZE, 51 .is_ip = 1, 52 .rx = rx, 53 .build_header = build_header, 54 .prepare_tx = prepare_tx, 55 .continue_tx = NULL, 56 .ack_tx = NULL 57}; 58 59 60static int __init arcnet_rfc1051_init(void) 61{ 62 printk(VERSION); 63 64 arc_proto_map[ARC_P_IP_RFC1051] 65 = arc_proto_map[ARC_P_ARP_RFC1051] 66 = &rfc1051_proto; 67 68 /* if someone else already owns the broadcast, we won't take it */ 69 if (arc_bcast_proto == arc_proto_default) 70 arc_bcast_proto = &rfc1051_proto; 71 72 return 0; 73} 74 75static void __exit arcnet_rfc1051_exit(void) 76{ 77 arcnet_unregister_proto(&rfc1051_proto); 78} 79 80module_init(arcnet_rfc1051_init); 81module_exit(arcnet_rfc1051_exit); 82 83MODULE_LICENSE("GPL"); 84 85/* 86 * Determine a packet's protocol ID. 87 * 88 * With ARCnet we have to convert everything to Ethernet-style stuff. 89 */ 90static __be16 type_trans(struct sk_buff *skb, struct net_device *dev) 91{ 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 dev->stats.rx_errors++; 116 dev->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 = netdev_priv(dev); 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 dev->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} 163 164 165/* 166 * Create the ARCnet hard/soft headers for RFC1051. 167 */ 168static int build_header(struct sk_buff *skb, struct net_device *dev, 169 unsigned short type, uint8_t daddr) 170{ 171 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 172 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size); 173 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 174 175 /* set the protocol ID according to RFC1051 */ 176 switch (type) { 177 case ETH_P_IP: 178 soft->proto = ARC_P_IP_RFC1051; 179 break; 180 case ETH_P_ARP: 181 soft->proto = ARC_P_ARP_RFC1051; 182 break; 183 default: 184 BUGMSG(D_NORMAL, "RFC1051: I don't understand protocol %d (%Xh)\n", 185 type, type); 186 dev->stats.tx_errors++; 187 dev->stats.tx_aborted_errors++; 188 return 0; 189 } 190 191 192 /* 193 * Set the source hardware address. 194 * 195 * This is pretty pointless for most purposes, but it can help in 196 * debugging. ARCnet does not allow us to change the source address in 197 * the actual packet sent) 198 */ 199 pkt->hard.source = *dev->dev_addr; 200 201 /* see linux/net/ethernet/eth.c to see where I got the following */ 202 203 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 204 /* 205 * FIXME: fill in the last byte of the dest ipaddr here to better 206 * comply with RFC1051 in "noarp" mode. 207 */ 208 pkt->hard.dest = 0; 209 return hdr_size; 210 } 211 /* otherwise, just fill it in and go! */ 212 pkt->hard.dest = daddr; 213 214 return hdr_size; /* success */ 215} 216 217 218static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 219 int bufnum) 220{ 221 struct arcnet_local *lp = netdev_priv(dev); 222 struct arc_hardware *hard = &pkt->hard; 223 int ofs; 224 225 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n", 226 lp->next_tx, lp->cur_tx, bufnum); 227 228 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */ 229 230 if (length > XMTU) { 231 /* should never happen! other people already check for this. */ 232 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n", 233 length, XMTU); 234 length = XMTU; 235 } 236 if (length > MinTU) { 237 hard->offset[0] = 0; 238 hard->offset[1] = ofs = 512 - length; 239 } else if (length > MTU) { 240 hard->offset[0] = 0; 241 hard->offset[1] = ofs = 512 - length - 3; 242 } else 243 hard->offset[0] = ofs = 256 - length; 244 245 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 246 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 247 248 lp->lastload_dest = hard->dest; 249 250 return 1; /* done */ 251} 252