1/* 2 * Linux ARCnet driver - "raw mode" packet encapsulation (no soft headers) 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#include <linux/module.h> 28#include <linux/gfp.h> 29#include <linux/init.h> 30#include <linux/if_arp.h> 31#include <net/arp.h> 32#include <linux/netdevice.h> 33#include <linux/skbuff.h> 34#include <linux/arcdevice.h> 35 36#define VERSION "arcnet: raw mode (`r') encapsulation support loaded.\n" 37 38 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 46static struct ArcProto rawmode_proto = 47{ 48 .suffix = 'r', 49 .mtu = XMTU, 50 .rx = rx, 51 .build_header = build_header, 52 .prepare_tx = prepare_tx, 53 .continue_tx = NULL, 54 .ack_tx = NULL 55}; 56 57 58static int __init arcnet_raw_init(void) 59{ 60 int count; 61 62 printk(VERSION); 63 64 for (count = 0; count < 256; count++) 65 if (arc_proto_map[count] == arc_proto_default) 66 arc_proto_map[count] = &rawmode_proto; 67 68 /* for raw mode, we only set the bcast proto if there's no better one */ 69 if (arc_bcast_proto == arc_proto_default) 70 arc_bcast_proto = &rawmode_proto; 71 72 arc_proto_default = &rawmode_proto; 73 return 0; 74} 75 76static void __exit arcnet_raw_exit(void) 77{ 78 arcnet_unregister_proto(&rawmode_proto); 79} 80 81module_init(arcnet_raw_init); 82module_exit(arcnet_raw_exit); 83 84MODULE_LICENSE("GPL"); 85 86 87/* packet receiver */ 88static void rx(struct net_device *dev, int bufnum, 89 struct archdr *pkthdr, int length) 90{ 91 struct arcnet_local *lp = netdev_priv(dev); 92 struct sk_buff *skb; 93 struct archdr *pkt = pkthdr; 94 int ofs; 95 96 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length); 97 98 if (length > MTU) 99 ofs = 512 - length; 100 else 101 ofs = 256 - length; 102 103 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 104 if (skb == NULL) { 105 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n"); 106 dev->stats.rx_dropped++; 107 return; 108 } 109 skb_put(skb, length + ARC_HDR_SIZE); 110 skb->dev = dev; 111 112 pkt = (struct archdr *) skb->data; 113 114 skb_reset_mac_header(skb); 115 skb_pull(skb, ARC_HDR_SIZE); 116 117 /* up to sizeof(pkt->soft) has already been copied from the card */ 118 memcpy(pkt, pkthdr, sizeof(struct archdr)); 119 if (length > sizeof(pkt->soft)) 120 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 121 pkt->soft.raw + sizeof(pkt->soft), 122 length - sizeof(pkt->soft)); 123 124 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx"); 125 126 skb->protocol = cpu_to_be16(ETH_P_ARCNET); 127 netif_rx(skb); 128} 129 130 131/* 132 * Create the ARCnet hard/soft headers for raw mode. 133 * There aren't any soft headers in raw mode - not even the protocol id. 134 */ 135static int build_header(struct sk_buff *skb, struct net_device *dev, 136 unsigned short type, uint8_t daddr) 137{ 138 int hdr_size = ARC_HDR_SIZE; 139 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size); 140 141 /* 142 * Set the source hardware address. 143 * 144 * This is pretty pointless for most purposes, but it can help in 145 * debugging. ARCnet does not allow us to change the source address in 146 * the actual packet sent) 147 */ 148 pkt->hard.source = *dev->dev_addr; 149 150 /* see linux/net/ethernet/eth.c to see where I got the following */ 151 152 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 153 pkt->hard.dest = 0; 154 return hdr_size; 155 } 156 /* otherwise, just fill it in and go! */ 157 pkt->hard.dest = daddr; 158 159 return hdr_size; /* success */ 160} 161 162 163static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 164 int bufnum) 165{ 166 struct arcnet_local *lp = netdev_priv(dev); 167 struct arc_hardware *hard = &pkt->hard; 168 int ofs; 169 170 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n", 171 lp->next_tx, lp->cur_tx, bufnum); 172 173 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */ 174 175 if (length > XMTU) { 176 /* should never happen! other people already check for this. */ 177 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n", 178 length, XMTU); 179 length = XMTU; 180 } 181 if (length >= MinTU) { 182 hard->offset[0] = 0; 183 hard->offset[1] = ofs = 512 - length; 184 } else if (length > MTU) { 185 hard->offset[0] = 0; 186 hard->offset[1] = ofs = 512 - length - 3; 187 } else 188 hard->offset[0] = ofs = 256 - length; 189 190 BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n", 191 length,ofs); 192 193 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 194 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 195 196 lp->lastload_dest = hard->dest; 197 198 return 1; /* done */ 199} 200