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 37 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev); 38 static void rx(struct net_device *dev, int bufnum, 39 struct archdr *pkthdr, int length); 40 static int build_header(struct sk_buff *skb, struct net_device *dev, 41 unsigned short type, uint8_t daddr); 42 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 43 int bufnum); 44 45 46 static 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 59 static 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 74 static void __exit arcnet_rfc1051_exit(void) 75 { 76 arcnet_unregister_proto(&rfc1051_proto); 77 } 78 79 module_init(arcnet_rfc1051_init); 80 module_exit(arcnet_rfc1051_exit); 81 82 MODULE_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 */ 89 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev) 90 { 91 struct archdr *pkt = (struct archdr *) skb->data; 92 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 93 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 94 95 /* Pull off the arcnet header. */ 96 skb_reset_mac_header(skb); 97 skb_pull(skb, hdr_size); 98 99 if (pkt->hard.dest == 0) 100 skb->pkt_type = PACKET_BROADCAST; 101 else if (dev->flags & IFF_PROMISC) { 102 /* if we're not sending to ourselves :) */ 103 if (pkt->hard.dest != dev->dev_addr[0]) 104 skb->pkt_type = PACKET_OTHERHOST; 105 } 106 /* now return the protocol number */ 107 switch (soft->proto) { 108 case ARC_P_IP_RFC1051: 109 return htons(ETH_P_IP); 110 case ARC_P_ARP_RFC1051: 111 return htons(ETH_P_ARP); 112 113 default: 114 dev->stats.rx_errors++; 115 dev->stats.rx_crc_errors++; 116 return 0; 117 } 118 119 return htons(ETH_P_IP); 120 } 121 122 123 /* packet receiver */ 124 static void rx(struct net_device *dev, int bufnum, 125 struct archdr *pkthdr, int length) 126 { 127 struct arcnet_local *lp = netdev_priv(dev); 128 struct sk_buff *skb; 129 struct archdr *pkt = pkthdr; 130 int ofs; 131 132 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length); 133 134 if (length >= MinTU) 135 ofs = 512 - length; 136 else 137 ofs = 256 - length; 138 139 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 140 if (skb == NULL) { 141 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n"); 142 dev->stats.rx_dropped++; 143 return; 144 } 145 skb_put(skb, length + ARC_HDR_SIZE); 146 skb->dev = dev; 147 148 pkt = (struct archdr *) skb->data; 149 150 /* up to sizeof(pkt->soft) has already been copied from the card */ 151 memcpy(pkt, pkthdr, sizeof(struct archdr)); 152 if (length > sizeof(pkt->soft)) 153 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 154 pkt->soft.raw + sizeof(pkt->soft), 155 length - sizeof(pkt->soft)); 156 157 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx"); 158 159 skb->protocol = type_trans(skb, dev); 160 netif_rx(skb); 161 } 162 163 164 /* 165 * Create the ARCnet hard/soft headers for RFC1051. 166 */ 167 static int build_header(struct sk_buff *skb, struct net_device *dev, 168 unsigned short type, uint8_t daddr) 169 { 170 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 171 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size); 172 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 173 174 /* set the protocol ID according to RFC1051 */ 175 switch (type) { 176 case ETH_P_IP: 177 soft->proto = ARC_P_IP_RFC1051; 178 break; 179 case ETH_P_ARP: 180 soft->proto = ARC_P_ARP_RFC1051; 181 break; 182 default: 183 BUGMSG(D_NORMAL, "RFC1051: I don't understand protocol %d (%Xh)\n", 184 type, type); 185 dev->stats.tx_errors++; 186 dev->stats.tx_aborted_errors++; 187 return 0; 188 } 189 190 191 /* 192 * Set the source hardware address. 193 * 194 * This is pretty pointless for most purposes, but it can help in 195 * debugging. ARCnet does not allow us to change the source address in 196 * the actual packet sent) 197 */ 198 pkt->hard.source = *dev->dev_addr; 199 200 /* see linux/net/ethernet/eth.c to see where I got the following */ 201 202 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 203 /* 204 * FIXME: fill in the last byte of the dest ipaddr here to better 205 * comply with RFC1051 in "noarp" mode. 206 */ 207 pkt->hard.dest = 0; 208 return hdr_size; 209 } 210 /* otherwise, just fill it in and go! */ 211 pkt->hard.dest = daddr; 212 213 return hdr_size; /* success */ 214 } 215 216 217 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 218 int bufnum) 219 { 220 struct arcnet_local *lp = netdev_priv(dev); 221 struct arc_hardware *hard = &pkt->hard; 222 int ofs; 223 224 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n", 225 lp->next_tx, lp->cur_tx, bufnum); 226 227 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */ 228 229 if (length > XMTU) { 230 /* should never happen! other people already check for this. */ 231 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n", 232 length, XMTU); 233 length = XMTU; 234 } 235 if (length > MinTU) { 236 hard->offset[0] = 0; 237 hard->offset[1] = ofs = 512 - length; 238 } else if (length > MTU) { 239 hard->offset[0] = 0; 240 hard->offset[1] = ofs = 512 - length - 3; 241 } else 242 hard->offset[0] = ofs = 256 - length; 243 244 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 245 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 246 247 lp->lastload_dest = hard->dest; 248 249 return 1; /* done */ 250 } 251