aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/arcnet/capmode.c
blob: 6c764b66e9cc6fba1c71482324c9f9a52ef555e1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/*
 * Linux ARCnet driver - "cap mode" packet encapsulation.
 * It adds sequence numbers to packets for communicating between a user space
 * application and the driver. After a transmit it sends a packet with protocol
 * byte 0 back up to the userspace containing the sequence number of the packet
 * plus the transmit-status on the ArcNet.
 *
 * Written 2002-4 by Esben Nielsen, Vestas Wind Systems A/S
 * Derived from arc-rawmode.c by Avery Pennarun.
 * arc-rawmode was in turned based on skeleton.c, see below.
 *
 * **********************
 *
 * The original copyright of skeleton.c was as follows:
 *
 * skeleton.c Written 1993 by Donald Becker.
 * Copyright 1993 United States Government as represented by the
 * Director, National Security Agency.  This software may only be used
 * and distributed according to the terms of the GNU General Public License as
 * modified by SRC, incorporated herein by reference.
 *
 * **********************
 *
 * For more details, see drivers/net/arcnet.c
 *
 * **********************
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/if_arp.h>
#include <net/arp.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/arcdevice.h>

#define VERSION "arcnet: cap mode (`c') encapsulation support loaded.\n"


static void rx(struct net_device *dev, int bufnum,
	       struct archdr *pkthdr, int length);
static int build_header(struct sk_buff *skb,
			struct net_device *dev,
			unsigned short type,
			uint8_t daddr);
static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
		      int bufnum);
static int ack_tx(struct net_device *dev, int acked);


static struct ArcProto capmode_proto =
{
	'r',
	XMTU,
	0,
       	rx,
	build_header,
	prepare_tx,
	NULL,
	ack_tx
};


void arcnet_cap_init(void)
{
	int count;

	for (count = 1; count <= 8; count++)
		if (arc_proto_map[count] == arc_proto_default)
			arc_proto_map[count] = &capmode_proto;

	/* for cap mode, we only set the bcast proto if there's no better one */
	if (arc_bcast_proto == arc_proto_default)
		arc_bcast_proto = &capmode_proto;

	arc_proto_default = &capmode_proto;
	arc_raw_proto = &capmode_proto;
}


#ifdef MODULE

int __init init_module(void)
{
	printk(VERSION);
	arcnet_cap_init();
	return 0;
}

void cleanup_module(void)
{
	arcnet_unregister_proto(&capmode_proto);
}

MODULE_LICENSE("GPL");
#endif				/* MODULE */



/* packet receiver */
static void rx(struct net_device *dev, int bufnum,
	       struct archdr *pkthdr, int length)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	struct sk_buff *skb;
	struct archdr *pkt = pkthdr;
	char *pktbuf, *pkthdrbuf;
	int ofs;

	BUGMSG(D_DURING, "it's a raw(cap) packet (length=%d)\n", length);

	if (length >= MinTU)
		ofs = 512 - length;
	else
		ofs = 256 - length;

	skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
	if (skb == NULL) {
		BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
		lp->stats.rx_dropped++;
		return;
	}
	skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
	skb->dev = dev;
	skb_reset_mac_header(skb);
	pkt = (struct archdr *)skb->mac.raw;
	skb_pull(skb, ARC_HDR_SIZE);

	/* up to sizeof(pkt->soft) has already been copied from the card */
	/* squeeze in an int for the cap encapsulation */

	/* use these variables to be sure we count in bytes, not in
	   sizeof(struct archdr) */
	pktbuf=(char*)pkt;
	pkthdrbuf=(char*)pkthdr;
	memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto));
	memcpy(pktbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto)+sizeof(int),
	       pkthdrbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto),
	       sizeof(struct archdr)-ARC_HDR_SIZE-sizeof(pkt->soft.cap.proto));

	if (length > sizeof(pkt->soft))
		lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
				      pkt->soft.raw + sizeof(pkt->soft)
				      + sizeof(int),
				      length - sizeof(pkt->soft));

	BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");

	skb->protocol = __constant_htons(ETH_P_ARCNET);
;
	netif_rx(skb);
	dev->last_rx = jiffies;
}


/*
 * Create the ARCnet hard/soft headers for cap mode.
 * There aren't any soft headers in cap mode - not even the protocol id.
 */
static int build_header(struct sk_buff *skb,
			struct net_device *dev,
			unsigned short type,
			uint8_t daddr)
{
	int hdr_size = ARC_HDR_SIZE;
	struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);

	BUGMSG(D_PROTO, "Preparing header for cap packet %x.\n",
	       *((int*)&pkt->soft.cap.cookie[0]));
	/*
	 * Set the source hardware address.
	 *
	 * This is pretty pointless for most purposes, but it can help in
	 * debugging.  ARCnet does not allow us to change the source address in
	 * the actual packet sent)
	 */
	pkt->hard.source = *dev->dev_addr;

	/* see linux/net/ethernet/eth.c to see where I got the following */

	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
		/*
		 * FIXME: fill in the last byte of the dest ipaddr here to better
		 * comply with RFC1051 in "noarp" mode.
		 */
		pkt->hard.dest = 0;
		return hdr_size;
	}
	/* otherwise, just fill it in and go! */
	pkt->hard.dest = daddr;

	return hdr_size;	/* success */
}


static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
		      int bufnum)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	struct arc_hardware *hard = &pkt->hard;
	int ofs;


	/* hard header is not included in packet length */
	length -= ARC_HDR_SIZE;
	/* And neither is the cookie field */
	length -= sizeof(int);

	BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
	       lp->next_tx, lp->cur_tx, bufnum);

	BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
	       *((int*)&pkt->soft.cap.cookie[0]));

	if (length > XMTU) {
		/* should never happen! other people already check for this. */
		BUGMSG(D_NORMAL, "Bug!  prepare_tx with size %d (> %d)\n",
		       length, XMTU);
		length = XMTU;
	}
	if (length > MinTU) {
		hard->offset[0] = 0;
		hard->offset[1] = ofs = 512 - length;
	} else if (length > MTU) {
		hard->offset[0] = 0;
		hard->offset[1] = ofs = 512 - length - 3;
	} else
		hard->offset[0] = ofs = 256 - length;

	BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n",
	       length,ofs);

	// Copy the arcnet-header + the protocol byte down:
	lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
	lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
			    sizeof(pkt->soft.cap.proto));

	// Skip the extra integer we have written into it as a cookie
	// but write the rest of the message:
	lp->hw.copy_to_card(dev, bufnum, ofs+1,
			    ((unsigned char*)&pkt->soft.cap.mes),length-1);

	lp->lastload_dest = hard->dest;

	return 1;		/* done */
}


static int ack_tx(struct net_device *dev, int acked)
{
  struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
  struct sk_buff *ackskb;
  struct archdr *ackpkt;
  int length=sizeof(struct arc_cap);

  BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
	 lp->outgoing.skb->protocol, acked);

  BUGLVL(D_SKB) arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");

  /* Now alloc a skb to send back up through the layers: */
  ackskb = alloc_skb(length + ARC_HDR_SIZE , GFP_ATOMIC);
  if (ackskb == NULL) {
	  BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
	  goto free_outskb;
  }

  skb_put(ackskb, length + ARC_HDR_SIZE );
  ackskb->dev = dev;

  skb_reset_mac_header(ackskb);
  ackpkt = (struct archdr *)ackskb->mac.raw;
  /* skb_pull(ackskb, ARC_HDR_SIZE); */


  memcpy(ackpkt, lp->outgoing.skb->data, ARC_HDR_SIZE+sizeof(struct arc_cap));
  ackpkt->soft.cap.proto=0; /* using protocol 0 for acknowledge */
  ackpkt->soft.cap.mes.ack=acked;

  BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
	 *((int*)&ackpkt->soft.cap.cookie[0]));

  ackskb->protocol = __constant_htons(ETH_P_ARCNET);

  BUGLVL(D_SKB) arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
  netif_rx(ackskb);

 free_outskb:
  dev_kfree_skb_irq(lp->outgoing.skb);
  lp->outgoing.proto = NULL; /* We are always finished when in this protocol */

  return 0;
}