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 27 #define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt 28 29 #include <linux/module.h> 30 #include <linux/gfp.h> 31 #include <linux/init.h> 32 #include <linux/if_arp.h> 33 #include <net/arp.h> 34 #include <linux/netdevice.h> 35 #include <linux/skbuff.h> 36 37 #include "arcdevice.h" 38 39 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev); 40 static void rx(struct net_device *dev, int bufnum, 41 struct archdr *pkthdr, int length); 42 static int build_header(struct sk_buff *skb, struct net_device *dev, 43 unsigned short type, uint8_t daddr); 44 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 45 int bufnum); 46 47 static struct ArcProto rfc1051_proto = { 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 static int __init arcnet_rfc1051_init(void) 59 { 60 pr_info("%s\n", "RFC1051 \"simple standard\" (`s') encapsulation support loaded"); 61 62 arc_proto_map[ARC_P_IP_RFC1051] 63 = arc_proto_map[ARC_P_ARP_RFC1051] 64 = &rfc1051_proto; 65 66 /* if someone else already owns the broadcast, we won't take it */ 67 if (arc_bcast_proto == arc_proto_default) 68 arc_bcast_proto = &rfc1051_proto; 69 70 return 0; 71 } 72 73 static void __exit arcnet_rfc1051_exit(void) 74 { 75 arcnet_unregister_proto(&rfc1051_proto); 76 } 77 78 module_init(arcnet_rfc1051_init); 79 module_exit(arcnet_rfc1051_exit); 80 81 MODULE_LICENSE("GPL"); 82 83 /* Determine a packet's protocol ID. 84 * 85 * With ARCnet we have to convert everything to Ethernet-style stuff. 86 */ 87 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev) 88 { 89 struct archdr *pkt = (struct archdr *)skb->data; 90 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 91 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 92 93 /* Pull off the arcnet header. */ 94 skb_reset_mac_header(skb); 95 skb_pull(skb, hdr_size); 96 97 if (pkt->hard.dest == 0) { 98 skb->pkt_type = PACKET_BROADCAST; 99 } else if (dev->flags & IFF_PROMISC) { 100 /* if we're not sending to ourselves :) */ 101 if (pkt->hard.dest != dev->dev_addr[0]) 102 skb->pkt_type = PACKET_OTHERHOST; 103 } 104 /* now return the protocol number */ 105 switch (soft->proto) { 106 case ARC_P_IP_RFC1051: 107 return htons(ETH_P_IP); 108 case ARC_P_ARP_RFC1051: 109 return htons(ETH_P_ARP); 110 111 default: 112 dev->stats.rx_errors++; 113 dev->stats.rx_crc_errors++; 114 return 0; 115 } 116 117 return htons(ETH_P_IP); 118 } 119 120 /* packet receiver */ 121 static void rx(struct net_device *dev, int bufnum, 122 struct archdr *pkthdr, int length) 123 { 124 struct arcnet_local *lp = netdev_priv(dev); 125 struct sk_buff *skb; 126 struct archdr *pkt = pkthdr; 127 int ofs; 128 129 arc_printk(D_DURING, dev, "it's a raw packet (length=%d)\n", length); 130 131 if (length >= MinTU) 132 ofs = 512 - length; 133 else 134 ofs = 256 - length; 135 136 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 137 if (!skb) { 138 dev->stats.rx_dropped++; 139 return; 140 } 141 skb_put(skb, length + ARC_HDR_SIZE); 142 skb->dev = dev; 143 144 pkt = (struct archdr *)skb->data; 145 146 /* up to sizeof(pkt->soft) has already been copied from the card */ 147 memcpy(pkt, pkthdr, sizeof(struct archdr)); 148 if (length > sizeof(pkt->soft)) 149 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 150 pkt->soft.raw + sizeof(pkt->soft), 151 length - sizeof(pkt->soft)); 152 153 if (BUGLVL(D_SKB)) 154 arcnet_dump_skb(dev, skb, "rx"); 155 156 skb->protocol = type_trans(skb, dev); 157 netif_rx(skb); 158 } 159 160 /* Create the ARCnet hard/soft headers for RFC1051 */ 161 static int build_header(struct sk_buff *skb, struct net_device *dev, 162 unsigned short type, uint8_t daddr) 163 { 164 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE; 165 struct archdr *pkt = skb_push(skb, hdr_size); 166 struct arc_rfc1051 *soft = &pkt->soft.rfc1051; 167 168 /* set the protocol ID according to RFC1051 */ 169 switch (type) { 170 case ETH_P_IP: 171 soft->proto = ARC_P_IP_RFC1051; 172 break; 173 case ETH_P_ARP: 174 soft->proto = ARC_P_ARP_RFC1051; 175 break; 176 default: 177 arc_printk(D_NORMAL, dev, "RFC1051: I don't understand protocol %d (%Xh)\n", 178 type, type); 179 dev->stats.tx_errors++; 180 dev->stats.tx_aborted_errors++; 181 return 0; 182 } 183 184 /* Set the source hardware address. 185 * 186 * This is pretty pointless for most purposes, but it can help in 187 * debugging. ARCnet does not allow us to change the source address 188 * in the actual packet sent. 189 */ 190 pkt->hard.source = *dev->dev_addr; 191 192 /* see linux/net/ethernet/eth.c to see where I got the following */ 193 194 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 195 /* FIXME: fill in the last byte of the dest ipaddr here to 196 * better comply with RFC1051 in "noarp" mode. 197 */ 198 pkt->hard.dest = 0; 199 return hdr_size; 200 } 201 /* otherwise, just fill it in and go! */ 202 pkt->hard.dest = daddr; 203 204 return hdr_size; /* success */ 205 } 206 207 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 208 int bufnum) 209 { 210 struct arcnet_local *lp = netdev_priv(dev); 211 struct arc_hardware *hard = &pkt->hard; 212 int ofs; 213 214 arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n", 215 lp->next_tx, lp->cur_tx, bufnum); 216 217 /* hard header is not included in packet length */ 218 length -= ARC_HDR_SIZE; 219 220 if (length > XMTU) { 221 /* should never happen! other people already check for this. */ 222 arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n", 223 length, XMTU); 224 length = XMTU; 225 } 226 if (length > MinTU) { 227 hard->offset[0] = 0; 228 hard->offset[1] = ofs = 512 - length; 229 } else if (length > MTU) { 230 hard->offset[0] = 0; 231 hard->offset[1] = ofs = 512 - length - 3; 232 } else { 233 hard->offset[0] = ofs = 256 - length; 234 } 235 236 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 237 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 238 239 lp->lastload_dest = hard->dest; 240 241 return 1; /* done */ 242 } 243