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269 lines · 7.5 KiB

1/*
2 * Linux ARCnet driver - "cap mode" packet encapsulation.
3 * It adds sequence numbers to packets for communicating between a user space
4 * application and the driver. After a transmit it sends a packet with protocol
5 * byte 0 back up to the userspace containing the sequence number of the packet
6 * plus the transmit-status on the ArcNet.
7 *
8 * Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
9 * Derived from arc-rawmode.c by Avery Pennarun.
10 * arc-rawmode was in turned based on skeleton.c, see below.
11 *
12 * **********************
13 *
14 * The original copyright of skeleton.c was as follows:
15 *
16 * skeleton.c Written 1993 by Donald Becker.
17 * Copyright 1993 United States Government as represented by the
18 * Director, National Security Agency. This software may only be used
19 * and distributed according to the terms of the GNU General Public License as
20 * modified by SRC, incorporated herein by reference.
21 *
22 * **********************
23 *
24 * For more details, see drivers/net/arcnet.c
25 *
26 * **********************
27 */
28
29#define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt
30
31#include <linux/module.h>
32#include <linux/gfp.h>
33#include <linux/init.h>
34#include <linux/if_arp.h>
35#include <net/arp.h>
36#include <linux/netdevice.h>
37#include <linux/skbuff.h>
38
39#include "arcdevice.h"
40
41/* packet receiver */
42static void rx(struct net_device *dev, int bufnum,
43 struct archdr *pkthdr, int length)
44{
45 struct arcnet_local *lp = netdev_priv(dev);
46 struct sk_buff *skb;
47 struct archdr *pkt;
48 char *pktbuf, *pkthdrbuf;
49 int ofs;
50
51 arc_printk(D_DURING, dev, "it's a raw(cap) packet (length=%d)\n",
52 length);
53
54 if (length >= MinTU)
55 ofs = 512 - length;
56 else
57 ofs = 256 - length;
58
59 skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
60 if (!skb) {
61 dev->stats.rx_dropped++;
62 return;
63 }
64 skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
65 skb->dev = dev;
66 skb_reset_mac_header(skb);
67 pkt = (struct archdr *)skb_mac_header(skb);
68 skb_pull(skb, ARC_HDR_SIZE);
69
70 /* up to sizeof(pkt->soft) has already been copied from the card
71 * squeeze in an int for the cap encapsulation
72 * use these variables to be sure we count in bytes, not in
73 * sizeof(struct archdr)
74 */
75 pktbuf = (char *)pkt;
76 pkthdrbuf = (char *)pkthdr;
77 memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto));
78 memcpy(pktbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto) + sizeof(int),
79 pkthdrbuf + ARC_HDR_SIZE + sizeof(pkt->soft.cap.proto),
80 sizeof(struct archdr) - ARC_HDR_SIZE - sizeof(pkt->soft.cap.proto));
81
82 if (length > sizeof(pkt->soft))
83 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
84 pkt->soft.raw + sizeof(pkt->soft)
85 + sizeof(int),
86 length - sizeof(pkt->soft));
87
88 if (BUGLVL(D_SKB))
89 arcnet_dump_skb(dev, skb, "rx");
90
91 skb->protocol = cpu_to_be16(ETH_P_ARCNET);
92 netif_rx(skb);
93}
94
95/* Create the ARCnet hard/soft headers for cap mode.
96 * There aren't any soft headers in cap mode - not even the protocol id.
97 */
98static int build_header(struct sk_buff *skb,
99 struct net_device *dev,
100 unsigned short type,
101 uint8_t daddr)
102{
103 int hdr_size = ARC_HDR_SIZE;
104 struct archdr *pkt = skb_push(skb, hdr_size);
105
106 arc_printk(D_PROTO, dev, "Preparing header for cap packet %x.\n",
107 *((int *)&pkt->soft.cap.cookie[0]));
108
109 /* Set the source hardware address.
110 *
111 * This is pretty pointless for most purposes, but it can help in
112 * debugging. ARCnet does not allow us to change the source address in
113 * the actual packet sent)
114 */
115 pkt->hard.source = *dev->dev_addr;
116
117 /* see linux/net/ethernet/eth.c to see where I got the following */
118
119 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
120 /* FIXME: fill in the last byte of the dest ipaddr here to
121 * better comply with RFC1051 in "noarp" mode.
122 */
123 pkt->hard.dest = 0;
124 return hdr_size;
125 }
126 /* otherwise, just fill it in and go! */
127 pkt->hard.dest = daddr;
128
129 return hdr_size; /* success */
130}
131
132static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
133 int bufnum)
134{
135 struct arcnet_local *lp = netdev_priv(dev);
136 struct arc_hardware *hard = &pkt->hard;
137 int ofs;
138
139 /* hard header is not included in packet length */
140 length -= ARC_HDR_SIZE;
141 /* And neither is the cookie field */
142 length -= sizeof(int);
143
144 arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
145 lp->next_tx, lp->cur_tx, bufnum);
146
147 arc_printk(D_PROTO, dev, "Sending for cap packet %x.\n",
148 *((int *)&pkt->soft.cap.cookie[0]));
149
150 if (length > XMTU) {
151 /* should never happen! other people already check for this. */
152 arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n",
153 length, XMTU);
154 length = XMTU;
155 }
156 if (length > MinTU) {
157 hard->offset[0] = 0;
158 hard->offset[1] = ofs = 512 - length;
159 } else if (length > MTU) {
160 hard->offset[0] = 0;
161 hard->offset[1] = ofs = 512 - length - 3;
162 } else {
163 hard->offset[0] = ofs = 256 - length;
164 }
165
166 arc_printk(D_DURING, dev, "prepare_tx: length=%d ofs=%d\n",
167 length, ofs);
168
169 /* Copy the arcnet-header + the protocol byte down: */
170 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
171 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
172 sizeof(pkt->soft.cap.proto));
173
174 /* Skip the extra integer we have written into it as a cookie
175 * but write the rest of the message:
176 */
177 lp->hw.copy_to_card(dev, bufnum, ofs + 1,
178 ((unsigned char *)&pkt->soft.cap.mes), length - 1);
179
180 lp->lastload_dest = hard->dest;
181
182 return 1; /* done */
183}
184
185static int ack_tx(struct net_device *dev, int acked)
186{
187 struct arcnet_local *lp = netdev_priv(dev);
188 struct sk_buff *ackskb;
189 struct archdr *ackpkt;
190 int length = sizeof(struct arc_cap);
191
192 arc_printk(D_DURING, dev, "capmode: ack_tx: protocol: %x: result: %d\n",
193 lp->outgoing.skb->protocol, acked);
194
195 if (BUGLVL(D_SKB))
196 arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
197
198 /* Now alloc a skb to send back up through the layers: */
199 ackskb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
200 if (!ackskb)
201 goto free_outskb;
202
203 skb_put(ackskb, length + ARC_HDR_SIZE);
204 ackskb->dev = dev;
205
206 skb_reset_mac_header(ackskb);
207 ackpkt = (struct archdr *)skb_mac_header(ackskb);
208 /* skb_pull(ackskb, ARC_HDR_SIZE); */
209
210 skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
211 ARC_HDR_SIZE + sizeof(struct arc_cap));
212 ackpkt->soft.cap.proto = 0; /* using protocol 0 for acknowledge */
213 ackpkt->soft.cap.mes.ack = acked;
214
215 arc_printk(D_PROTO, dev, "Acknowledge for cap packet %x.\n",
216 *((int *)&ackpkt->soft.cap.cookie[0]));
217
218 ackskb->protocol = cpu_to_be16(ETH_P_ARCNET);
219
220 if (BUGLVL(D_SKB))
221 arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
222 netif_rx(ackskb);
223
224free_outskb:
225 dev_kfree_skb_irq(lp->outgoing.skb);
226 lp->outgoing.proto = NULL;
227 /* We are always finished when in this protocol */
228
229 return 0;
230}
231
232static struct ArcProto capmode_proto = {
233 .suffix = 'r',
234 .mtu = XMTU,
235 .rx = rx,
236 .build_header = build_header,
237 .prepare_tx = prepare_tx,
238 .ack_tx = ack_tx
239};
240
241static int __init capmode_module_init(void)
242{
243 int count;
244
245 pr_info("cap mode (`c') encapsulation support loaded\n");
246
247 for (count = 1; count <= 8; count++)
248 if (arc_proto_map[count] == arc_proto_default)
249 arc_proto_map[count] = &capmode_proto;
250
251 /* for cap mode, we only set the bcast proto if there's no better one */
252 if (arc_bcast_proto == arc_proto_default)
253 arc_bcast_proto = &capmode_proto;
254
255 arc_proto_default = &capmode_proto;
256 arc_raw_proto = &capmode_proto;
257
258 return 0;
259}
260
261static void __exit capmode_module_exit(void)
262{
263 arcnet_unregister_proto(&capmode_proto);
264}
265module_init(capmode_module_init);
266module_exit(capmode_module_exit);
267
268MODULE_DESCRIPTION("ARCnet CAP mode packet interface module");
269MODULE_LICENSE("GPL");