2 * Linux ARCnet driver - RFC1051 ("simple" standard) packet encapsulation
4 * Written 1994-1999 by Avery Pennarun.
5 * Derived from skeleton.c by Donald Becker.
7 * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
8 * for sponsoring the further development of this driver.
10 * **********************
12 * The original copyright of skeleton.c was as follows:
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.
20 * **********************
22 * For more details, see drivers/net/arcnet.c
24 * **********************
26 #include <linux/module.h>
27 #include <linux/gfp.h>
28 #include <linux/init.h>
29 #include <linux/if_arp.h>
31 #include <linux/netdevice.h>
32 #include <linux/skbuff.h>
33 #include <linux/arcdevice.h>
35 #define VERSION "arcnet: RFC1051 \"simple standard\" (`s') encapsulation support loaded.\n"
38 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
39 static void rx(struct net_device *dev, int bufnum,
40 struct archdr *pkthdr, int length);
41 static int build_header(struct sk_buff *skb, struct net_device *dev,
42 unsigned short type, uint8_t daddr);
43 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
47 static struct ArcProto rfc1051_proto =
50 .mtu = XMTU - RFC1051_HDR_SIZE,
53 .build_header = build_header,
54 .prepare_tx = prepare_tx,
60 static int __init arcnet_rfc1051_init(void)
64 arc_proto_map[ARC_P_IP_RFC1051]
65 = arc_proto_map[ARC_P_ARP_RFC1051]
68 /* if someone else already owns the broadcast, we won't take it */
69 if (arc_bcast_proto == arc_proto_default)
70 arc_bcast_proto = &rfc1051_proto;
75 static void __exit arcnet_rfc1051_exit(void)
77 arcnet_unregister_proto(&rfc1051_proto);
80 module_init(arcnet_rfc1051_init);
81 module_exit(arcnet_rfc1051_exit);
83 MODULE_LICENSE("GPL");
86 * Determine a packet's protocol ID.
88 * With ARCnet we have to convert everything to Ethernet-style stuff.
90 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
92 struct archdr *pkt = (struct archdr *)skb->data;
93 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
94 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
96 /* Pull off the arcnet header. */
97 skb_reset_mac_header(skb);
98 skb_pull(skb, hdr_size);
100 if (pkt->hard.dest == 0)
101 skb->pkt_type = PACKET_BROADCAST;
102 else if (dev->flags & IFF_PROMISC) {
103 /* if we're not sending to ourselves :) */
104 if (pkt->hard.dest != dev->dev_addr[0])
105 skb->pkt_type = PACKET_OTHERHOST;
107 /* now return the protocol number */
108 switch (soft->proto) {
109 case ARC_P_IP_RFC1051:
110 return htons(ETH_P_IP);
111 case ARC_P_ARP_RFC1051:
112 return htons(ETH_P_ARP);
115 dev->stats.rx_errors++;
116 dev->stats.rx_crc_errors++;
120 return htons(ETH_P_IP);
124 /* packet receiver */
125 static void rx(struct net_device *dev, int bufnum,
126 struct archdr *pkthdr, int length)
128 struct arcnet_local *lp = netdev_priv(dev);
130 struct archdr *pkt = pkthdr;
133 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length);
140 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
142 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
143 dev->stats.rx_dropped++;
146 skb_put(skb, length + ARC_HDR_SIZE);
149 pkt = (struct archdr *)skb->data;
151 /* up to sizeof(pkt->soft) has already been copied from the card */
152 memcpy(pkt, pkthdr, sizeof(struct archdr));
153 if (length > sizeof(pkt->soft))
154 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
155 pkt->soft.raw + sizeof(pkt->soft),
156 length - sizeof(pkt->soft));
158 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
160 skb->protocol = type_trans(skb, dev);
166 * Create the ARCnet hard/soft headers for RFC1051.
168 static int build_header(struct sk_buff *skb, struct net_device *dev,
169 unsigned short type, uint8_t daddr)
171 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
172 struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
173 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
175 /* set the protocol ID according to RFC1051 */
178 soft->proto = ARC_P_IP_RFC1051;
181 soft->proto = ARC_P_ARP_RFC1051;
184 BUGMSG(D_NORMAL, "RFC1051: I don't understand protocol %d (%Xh)\n",
186 dev->stats.tx_errors++;
187 dev->stats.tx_aborted_errors++;
193 * Set the source hardware address.
195 * This is pretty pointless for most purposes, but it can help in
196 * debugging. ARCnet does not allow us to change the source address in
197 * the actual packet sent)
199 pkt->hard.source = *dev->dev_addr;
201 /* see linux/net/ethernet/eth.c to see where I got the following */
203 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
205 * FIXME: fill in the last byte of the dest ipaddr here to better
206 * comply with RFC1051 in "noarp" mode.
211 /* otherwise, just fill it in and go! */
212 pkt->hard.dest = daddr;
214 return hdr_size; /* success */
218 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
221 struct arcnet_local *lp = netdev_priv(dev);
222 struct arc_hardware *hard = &pkt->hard;
225 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
226 lp->next_tx, lp->cur_tx, bufnum);
228 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
231 /* should never happen! other people already check for this. */
232 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n",
236 if (length > MinTU) {
238 hard->offset[1] = ofs = 512 - length;
239 } else if (length > MTU) {
241 hard->offset[1] = ofs = 512 - length - 3;
243 hard->offset[0] = ofs = 256 - length;
245 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
246 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length);
248 lp->lastload_dest = hard->dest;