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 */
rx(struct net_device * dev,int bufnum,struct archdr * pkthdr,int length)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 */
build_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,uint8_t daddr)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
prepare_tx(struct net_device * dev,struct archdr * pkt,int length,int bufnum)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
arcnet_raw_init(void)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
arcnet_raw_exit(void)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_LICENSE("GPL");
190