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/init.h> 29 #include <linux/if_arp.h> 30 #include <net/arp.h> 31 #include <linux/netdevice.h> 32 #include <linux/skbuff.h> 33 #include <linux/arcdevice.h> 34 35 #define VERSION "arcnet: raw mode (`r') encapsulation support loaded.\n" 36 37 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 struct ArcProto rawmode_proto = 46 { 47 .suffix = 'r', 48 .mtu = XMTU, 49 .rx = rx, 50 .build_header = build_header, 51 .prepare_tx = prepare_tx, 52 .continue_tx = NULL, 53 .ack_tx = NULL 54 }; 55 56 57 static int __init arcnet_raw_init(void) 58 { 59 int count; 60 61 printk(VERSION); 62 63 for (count = 0; count < 256; count++) 64 if (arc_proto_map[count] == arc_proto_default) 65 arc_proto_map[count] = &rawmode_proto; 66 67 /* for raw mode, we only set the bcast proto if there's no better one */ 68 if (arc_bcast_proto == arc_proto_default) 69 arc_bcast_proto = &rawmode_proto; 70 71 arc_proto_default = &rawmode_proto; 72 return 0; 73 } 74 75 static void __exit arcnet_raw_exit(void) 76 { 77 arcnet_unregister_proto(&rawmode_proto); 78 } 79 80 module_init(arcnet_raw_init); 81 module_exit(arcnet_raw_exit); 82 83 MODULE_LICENSE("GPL"); 84 85 86 /* packet receiver */ 87 static void rx(struct net_device *dev, int bufnum, 88 struct archdr *pkthdr, int length) 89 { 90 struct arcnet_local *lp = dev->priv; 91 struct sk_buff *skb; 92 struct archdr *pkt = pkthdr; 93 int ofs; 94 95 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length); 96 97 if (length >= MinTU) 98 ofs = 512 - length; 99 else 100 ofs = 256 - length; 101 102 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC); 103 if (skb == NULL) { 104 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n"); 105 lp->stats.rx_dropped++; 106 return; 107 } 108 skb_put(skb, length + ARC_HDR_SIZE); 109 skb->dev = dev; 110 111 pkt = (struct archdr *) skb->data; 112 113 skb->mac.raw = skb->data; 114 skb_pull(skb, ARC_HDR_SIZE); 115 116 /* up to sizeof(pkt->soft) has already been copied from the card */ 117 memcpy(pkt, pkthdr, sizeof(struct archdr)); 118 if (length > sizeof(pkt->soft)) 119 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft), 120 pkt->soft.raw + sizeof(pkt->soft), 121 length - sizeof(pkt->soft)); 122 123 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx"); 124 125 skb->protocol = __constant_htons(ETH_P_ARCNET); 126 ; 127 netif_rx(skb); 128 dev->last_rx = jiffies; 129 } 130 131 132 /* 133 * Create the ARCnet hard/soft headers for raw mode. 134 * There aren't any soft headers in raw mode - not even the protocol id. 135 */ 136 static int build_header(struct sk_buff *skb, struct net_device *dev, 137 unsigned short type, uint8_t daddr) 138 { 139 int hdr_size = ARC_HDR_SIZE; 140 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size); 141 142 /* 143 * Set the source hardware address. 144 * 145 * This is pretty pointless for most purposes, but it can help in 146 * debugging. ARCnet does not allow us to change the source address in 147 * the actual packet sent) 148 */ 149 pkt->hard.source = *dev->dev_addr; 150 151 /* see linux/net/ethernet/eth.c to see where I got the following */ 152 153 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) { 154 /* 155 * FIXME: fill in the last byte of the dest ipaddr here to better 156 * comply with RFC1051 in "noarp" mode. 157 */ 158 pkt->hard.dest = 0; 159 return hdr_size; 160 } 161 /* otherwise, just fill it in and go! */ 162 pkt->hard.dest = daddr; 163 164 return hdr_size; /* success */ 165 } 166 167 168 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length, 169 int bufnum) 170 { 171 struct arcnet_local *lp = dev->priv; 172 struct arc_hardware *hard = &pkt->hard; 173 int ofs; 174 175 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n", 176 lp->next_tx, lp->cur_tx, bufnum); 177 178 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */ 179 180 if (length > XMTU) { 181 /* should never happen! other people already check for this. */ 182 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n", 183 length, XMTU); 184 length = XMTU; 185 } 186 if (length > MinTU) { 187 hard->offset[0] = 0; 188 hard->offset[1] = ofs = 512 - length; 189 } else if (length > MTU) { 190 hard->offset[0] = 0; 191 hard->offset[1] = ofs = 512 - length - 3; 192 } else 193 hard->offset[0] = ofs = 256 - length; 194 195 BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n", 196 length,ofs); 197 198 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE); 199 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length); 200 201 lp->lastload_dest = hard->dest; 202 203 return 1; /* done */ 204 } 205