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 #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 #include "arcdevice.h" 37 38 /* packet receiver */ 39 static void rx(struct net_device *dev, int bufnum, 40 struct archdr *pkthdr, int length) 41 { 42 struct arcnet_local *lp = netdev_priv(dev); 43 struct sk_buff *skb; 44 struct archdr *pkt = pkthdr; 45 int ofs; 46 47 arc_printk(D_DURING, dev, "it's a raw packet (length=%d)\n", length); 48 49 if (length > MTU) 50 ofs = 512 - length; 51 else 52 ofs = 256 - length; 53 54 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 55 if (!skb) { 56 dev->stats.rx_dropped++; 57 return; 58 } 59 skb_put(skb, length + ARC_HDR_SIZE); 60 skb->dev = dev; 61 62 pkt = (struct archdr *)skb->data; 63 64 skb_reset_mac_header(skb); 65 skb_pull(skb, ARC_HDR_SIZE); 66 67 /* up to sizeof(pkt->soft) has already been copied from the card */ 68 memcpy(pkt, pkthdr, sizeof(struct archdr)); 69 if (length > sizeof(pkt->soft)) 70 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 71 pkt->soft.raw + sizeof(pkt->soft), 72 length - sizeof(pkt->soft)); 73 74 if (BUGLVL(D_SKB)) 75 arcnet_dump_skb(dev, skb, "rx"); 76 77 skb->protocol = cpu_to_be16(ETH_P_ARCNET); 78 netif_rx(skb); 79 } 80 81 /* Create the ARCnet hard/soft headers for raw mode. 82 * There aren't any soft headers in raw mode - not even the protocol id. 83 */ 84 static int build_header(struct sk_buff *skb, struct net_device *dev, 85 unsigned short type, uint8_t daddr) 86 { 87 int hdr_size = ARC_HDR_SIZE; 88 struct archdr *pkt = skb_push(skb, hdr_size); 89 90 /* Set the source hardware address. 91 * 92 * This is pretty pointless for most purposes, but it can help in 93 * debugging. ARCnet does not allow us to change the source address 94 * in the actual packet sent. 95 */ 96 pkt->hard.source = *dev->dev_addr; 97 98 /* see linux/net/ethernet/eth.c to see where I got the following */ 99 100 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 101 /* FIXME: fill in the last byte of the dest ipaddr here 102 * to better comply with RFC1051 in "noarp" mode. 103 */ 104 pkt->hard.dest = 0; 105 return hdr_size; 106 } 107 /* otherwise, just fill it in and go! */ 108 pkt->hard.dest = daddr; 109 110 return hdr_size; /* success */ 111 } 112 113 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 114 int bufnum) 115 { 116 struct arcnet_local *lp = netdev_priv(dev); 117 struct arc_hardware *hard = &pkt->hard; 118 int ofs; 119 120 arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n", 121 lp->next_tx, lp->cur_tx, bufnum); 122 123 /* hard header is not included in packet length */ 124 length -= ARC_HDR_SIZE; 125 126 if (length > XMTU) { 127 /* should never happen! other people already check for this. */ 128 arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n", 129 length, XMTU); 130 length = XMTU; 131 } 132 if (length >= MinTU) { 133 hard->offset[0] = 0; 134 hard->offset[1] = ofs = 512 - length; 135 } else if (length > MTU) { 136 hard->offset[0] = 0; 137 hard->offset[1] = ofs = 512 - length - 3; 138 } else { 139 hard->offset[0] = ofs = 256 - length; 140 } 141 142 arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n", 143 length, ofs); 144 145 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 146 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 147 148 lp->lastload_dest = hard->dest; 149 150 return 1; /* done */ 151 } 152 153 static struct ArcProto rawmode_proto = { 154 .suffix = 'r', 155 .mtu = XMTU, 156 .rx = rx, 157 .build_header = build_header, 158 .prepare_tx = prepare_tx, 159 .continue_tx = NULL, 160 .ack_tx = NULL 161 }; 162 163 static int __init arcnet_raw_init(void) 164 { 165 int count; 166 167 pr_info("raw mode (`r') encapsulation support loaded\n"); 168 169 for (count = 0; count < 256; count++) 170 if (arc_proto_map[count] == arc_proto_default) 171 arc_proto_map[count] = &rawmode_proto; 172 173 /* for raw mode, we only set the bcast proto if there's no better one */ 174 if (arc_bcast_proto == arc_proto_default) 175 arc_bcast_proto = &rawmode_proto; 176 177 arc_proto_default = &rawmode_proto; 178 return 0; 179 } 180 181 static void __exit arcnet_raw_exit(void) 182 { 183 arcnet_unregister_proto(&rawmode_proto); 184 } 185 186 module_init(arcnet_raw_init); 187 module_exit(arcnet_raw_exit); 188 189 MODULE_DESCRIPTION("ARCnet raw mode packet interface module"); 190 MODULE_LICENSE("GPL"); 191