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 * **********************
27 #define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt
29 #include <linux/module.h>
30 #include <linux/gfp.h>
31 #include <linux/init.h>
32 #include <linux/if_arp.h>
34 #include <linux/netdevice.h>
35 #include <linux/skbuff.h>
36 #include <linux/arcdevice.h>
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,
46 static struct ArcProto rfc1051_proto = {
48 .mtu = XMTU - RFC1051_HDR_SIZE,
51 .build_header = build_header,
52 .prepare_tx = prepare_tx,
57 static int __init arcnet_rfc1051_init(void)
59 pr_info("%s\n", "RFC1051 \"simple standard\" (`s') encapsulation support loaded");
61 arc_proto_map[ARC_P_IP_RFC1051]
62 = arc_proto_map[ARC_P_ARP_RFC1051]
65 /* if someone else already owns the broadcast, we won't take it */
66 if (arc_bcast_proto == arc_proto_default)
67 arc_bcast_proto = &rfc1051_proto;
72 static void __exit arcnet_rfc1051_exit(void)
74 arcnet_unregister_proto(&rfc1051_proto);
77 module_init(arcnet_rfc1051_init);
78 module_exit(arcnet_rfc1051_exit);
80 MODULE_LICENSE("GPL");
82 /* Determine a packet's protocol ID.
84 * With ARCnet we have to convert everything to Ethernet-style stuff.
86 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
88 struct archdr *pkt = (struct archdr *)skb->data;
89 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
90 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
92 /* Pull off the arcnet header. */
93 skb_reset_mac_header(skb);
94 skb_pull(skb, hdr_size);
96 if (pkt->hard.dest == 0) {
97 skb->pkt_type = PACKET_BROADCAST;
98 } else if (dev->flags & IFF_PROMISC) {
99 /* if we're not sending to ourselves :) */
100 if (pkt->hard.dest != dev->dev_addr[0])
101 skb->pkt_type = PACKET_OTHERHOST;
103 /* now return the protocol number */
104 switch (soft->proto) {
105 case ARC_P_IP_RFC1051:
106 return htons(ETH_P_IP);
107 case ARC_P_ARP_RFC1051:
108 return htons(ETH_P_ARP);
111 dev->stats.rx_errors++;
112 dev->stats.rx_crc_errors++;
116 return htons(ETH_P_IP);
119 /* packet receiver */
120 static void rx(struct net_device *dev, int bufnum,
121 struct archdr *pkthdr, int length)
123 struct arcnet_local *lp = netdev_priv(dev);
125 struct archdr *pkt = pkthdr;
128 arc_printk(D_DURING, dev, "it's a raw packet (length=%d)\n", length);
135 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
137 dev->stats.rx_dropped++;
140 skb_put(skb, length + ARC_HDR_SIZE);
143 pkt = (struct archdr *)skb->data;
145 /* up to sizeof(pkt->soft) has already been copied from the card */
146 memcpy(pkt, pkthdr, sizeof(struct archdr));
147 if (length > sizeof(pkt->soft))
148 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
149 pkt->soft.raw + sizeof(pkt->soft),
150 length - sizeof(pkt->soft));
153 arcnet_dump_skb(dev, skb, "rx");
155 skb->protocol = type_trans(skb, dev);
159 /* Create the ARCnet hard/soft headers for RFC1051 */
160 static int build_header(struct sk_buff *skb, struct net_device *dev,
161 unsigned short type, uint8_t daddr)
163 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
164 struct archdr *pkt = (struct archdr *)skb_push(skb, hdr_size);
165 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
167 /* set the protocol ID according to RFC1051 */
170 soft->proto = ARC_P_IP_RFC1051;
173 soft->proto = ARC_P_ARP_RFC1051;
176 arc_printk(D_NORMAL, dev, "RFC1051: I don't understand protocol %d (%Xh)\n",
178 dev->stats.tx_errors++;
179 dev->stats.tx_aborted_errors++;
183 /* Set the source hardware address.
185 * This is pretty pointless for most purposes, but it can help in
186 * debugging. ARCnet does not allow us to change the source address
187 * in the actual packet sent.
189 pkt->hard.source = *dev->dev_addr;
191 /* see linux/net/ethernet/eth.c to see where I got the following */
193 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
194 /* FIXME: fill in the last byte of the dest ipaddr here to
195 * better comply with RFC1051 in "noarp" mode.
200 /* otherwise, just fill it in and go! */
201 pkt->hard.dest = daddr;
203 return hdr_size; /* success */
206 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
209 struct arcnet_local *lp = netdev_priv(dev);
210 struct arc_hardware *hard = &pkt->hard;
213 arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
214 lp->next_tx, lp->cur_tx, bufnum);
216 /* hard header is not included in packet length */
217 length -= ARC_HDR_SIZE;
220 /* should never happen! other people already check for this. */
221 arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n",
225 if (length > MinTU) {
227 hard->offset[1] = ofs = 512 - length;
228 } else if (length > MTU) {
230 hard->offset[1] = ofs = 512 - length - 3;
232 hard->offset[0] = ofs = 256 - length;
235 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
236 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length);
238 lp->lastload_dest = hard->dest;