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, unsigned short type, 41 uint8_t daddr); 42static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 43 int bufnum); 44 45 46struct ArcProto rfc1051_proto = 47{ 48 's', 49 XMTU - RFC1051_HDR_SIZE, 50 rx, 51 build_header, 52 prepare_tx 53}; 54 55 56void __init arcnet_rfc1051_init(void) 57{ 58 arc_proto_map[ARC_P_IP_RFC1051] 59 = arc_proto_map[ARC_P_ARP_RFC1051] 60 = &rfc1051_proto; 61 62 /* if someone else already owns the broadcast, we won't take it */ 63 if (arc_bcast_proto == arc_proto_default) 64 arc_bcast_proto = &rfc1051_proto; 65 66} 67 68 69#ifdef MODULE 70 71MODULE_LICENSE("GPL"); 72 73int __init init_module(void) 74{ 75 printk(VERSION); 76 arcnet_rfc1051_init(); 77 return 0; 78} 79 80void cleanup_module(void) 81{ 82 arcnet_unregister_proto(&rfc1051_proto); 83} 84 85#endif /* MODULE */ 86 87 88/* 89 * Determine a packet's protocol ID. 90 * 91 * With ARCnet we have to convert everything to Ethernet-style stuff. 92 */ 93static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev) 94{ 95 struct arcnet_local *lp = (struct arcnet_local *) dev->priv; 96 struct archdr *pkt = (struct archdr *) skb->data; 97 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 98 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 99 100 /* Pull off the arcnet header. */ 101 skb->mac.raw = skb->data; 102 skb_pull(skb, hdr_size); 103 104 if (pkt->hard.dest == 0) 105 skb->pkt_type = PACKET_BROADCAST; 106 else if (dev->flags & IFF_PROMISC) { 107 /* if we're not sending to ourselves :) */ 108 if (pkt->hard.dest != dev->dev_addr[0]) 109 skb->pkt_type = PACKET_OTHERHOST; 110 } 111 /* now return the protocol number */ 112 switch (soft->proto) { 113 case ARC_P_IP_RFC1051: 114 return htons(ETH_P_IP); 115 case ARC_P_ARP_RFC1051: 116 return htons(ETH_P_ARP); 117 118 default: 119 lp->stats.rx_errors++; 120 lp->stats.rx_crc_errors++; 121 return 0; 122 } 123 124 return htons(ETH_P_IP); 125} 126 127 128/* packet receiver */ 129static void rx(struct net_device *dev, int bufnum, 130 struct archdr *pkthdr, int length) 131{ 132 struct arcnet_local *lp = (struct arcnet_local *) dev->priv; 133 struct sk_buff *skb; 134 struct archdr *pkt = pkthdr; 135 int ofs; 136 137 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length); 138 139 if (length >= MinTU) 140 ofs = 512 - length; 141 else 142 ofs = 256 - length; 143 144 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 145 if (skb == NULL) { 146 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n"); 147 lp->stats.rx_dropped++; 148 return; 149 } 150 skb_put(skb, length + ARC_HDR_SIZE); 151 skb->dev = dev; 152 153 pkt = (struct archdr *) skb->data; 154 155 /* up to sizeof(pkt->soft) has already been copied from the card */ 156 memcpy(pkt, pkthdr, sizeof(struct archdr)); 157 if (length > sizeof(pkt->soft)) 158 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 159 pkt->soft.raw + sizeof(pkt->soft), 160 length - sizeof(pkt->soft)); 161 162 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx"); 163 164 skb->protocol = type_trans(skb, dev); 165 netif_rx(skb); 166 dev->last_rx = jiffies; 167} 168 169 170/* 171 * Create the ARCnet hard/soft headers for RFC1051. 172 */ 173static int build_header(struct sk_buff *skb, unsigned short type, 174 uint8_t daddr) 175{ 176 struct net_device *dev = skb->dev; 177 struct arcnet_local *lp = (struct arcnet_local *) dev->priv; 178 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 179 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size); 180 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 181 182 /* set the protocol ID according to RFC1051 */ 183 switch (type) { 184 case ETH_P_IP: 185 soft->proto = ARC_P_IP_RFC1051; 186 break; 187 case ETH_P_ARP: 188 soft->proto = ARC_P_ARP_RFC1051; 189 break; 190 default: 191 BUGMSG(D_NORMAL, "RFC1051: I don't understand protocol %d (%Xh)\n", 192 type, type); 193 lp->stats.tx_errors++; 194 lp->stats.tx_aborted_errors++; 195 return 0; 196 } 197 198 199 /* 200 * Set the source hardware address. 201 * 202 * This is pretty pointless for most purposes, but it can help in 203 * debugging. ARCnet does not allow us to change the source address in 204 * the actual packet sent) 205 */ 206 pkt->hard.source = *dev->dev_addr; 207 208 /* see linux/net/ethernet/eth.c to see where I got the following */ 209 210 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 211 pkt->hard.dest = 0; 212 return hdr_size; 213 } 214 /* otherwise, just fill it in and go! */ 215 pkt->hard.dest = daddr; 216 217 return hdr_size; /* success */ 218} 219 220 221static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 222 int bufnum) 223{ 224 struct arcnet_local *lp = (struct arcnet_local *) dev->priv; 225 struct arc_hardware *hard = &pkt->hard; 226 int ofs; 227 228 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n", 229 lp->next_tx, lp->cur_tx, bufnum); 230 231 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */ 232 233 if (length > XMTU) { 234 /* should never happen! other people already check for this. */ 235 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n", 236 length, XMTU); 237 length = XMTU; 238 } 239 if (length > MinTU) { 240 hard->offset[0] = 0; 241 hard->offset[1] = ofs = 512 - length; 242 } else if (length > MTU) { 243 hard->offset[0] = 0; 244 hard->offset[1] = ofs = 512 - length - 3; 245 } else 246 hard->offset[0] = ofs = 256 - length; 247 248 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 249 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 250 251 lp->lastload_dest = hard->dest; 252 253 return 1; /* done */ 254} 255