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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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#include <linux/module.h>
30#include <linux/init.h>
31#include <linux/if_arp.h>
32#include <net/arp.h>
33#include <linux/netdevice.h>
34#include <linux/skbuff.h>
35#include <linux/arcdevice.h>
36
37#define VERSION "arcnet: cap mode (`c') encapsulation support loaded.\n"
38
39
40static void rx(struct net_device *dev, int bufnum,
41 struct archdr *pkthdr, int length);
42static int build_header(struct sk_buff *skb,
43 struct net_device *dev,
44 unsigned short type,
45 uint8_t daddr);
46static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
47 int bufnum);
48static int ack_tx(struct net_device *dev, int acked);
49
50
Adrian Bunk75c96f82005-05-05 16:16:09 -070051static struct ArcProto capmode_proto =
Linus Torvalds1da177e2005-04-16 15:20:36 -070052{
53 'r',
54 XMTU,
55 0,
56 rx,
57 build_header,
58 prepare_tx,
59 NULL,
60 ack_tx
61};
62
63
64void arcnet_cap_init(void)
65{
66 int count;
67
68 for (count = 1; count <= 8; count++)
69 if (arc_proto_map[count] == arc_proto_default)
70 arc_proto_map[count] = &capmode_proto;
71
72 /* for cap mode, we only set the bcast proto if there's no better one */
73 if (arc_bcast_proto == arc_proto_default)
74 arc_bcast_proto = &capmode_proto;
75
76 arc_proto_default = &capmode_proto;
77 arc_raw_proto = &capmode_proto;
78}
79
80
81#ifdef MODULE
82
Jon Schindler7249d4c2008-03-05 18:49:51 -080083static int __init capmode_module_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084{
85 printk(VERSION);
86 arcnet_cap_init();
87 return 0;
88}
89
Jon Schindler7249d4c2008-03-05 18:49:51 -080090static void __exit capmode_module_exit(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070091{
92 arcnet_unregister_proto(&capmode_proto);
93}
Jon Schindler7249d4c2008-03-05 18:49:51 -080094module_init(capmode_module_init);
95module_exit(capmode_module_exit);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97MODULE_LICENSE("GPL");
98#endif /* MODULE */
99
100
101
102/* packet receiver */
103static void rx(struct net_device *dev, int bufnum,
104 struct archdr *pkthdr, int length)
105{
106 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
107 struct sk_buff *skb;
108 struct archdr *pkt = pkthdr;
109 char *pktbuf, *pkthdrbuf;
110 int ofs;
111
112 BUGMSG(D_DURING, "it's a raw(cap) packet (length=%d)\n", length);
113
114 if (length >= MinTU)
115 ofs = 512 - length;
116 else
117 ofs = 256 - length;
118
119 skb = alloc_skb(length + ARC_HDR_SIZE + sizeof(int), GFP_ATOMIC);
120 if (skb == NULL) {
121 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
122 lp->stats.rx_dropped++;
123 return;
124 }
125 skb_put(skb, length + ARC_HDR_SIZE + sizeof(int));
126 skb->dev = dev;
Arnaldo Carvalho de Melo459a98e2007-03-19 15:30:44 -0700127 skb_reset_mac_header(skb);
Arnaldo Carvalho de Melo98e399f2007-03-19 15:33:04 -0700128 pkt = (struct archdr *)skb_mac_header(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 skb_pull(skb, ARC_HDR_SIZE);
130
131 /* up to sizeof(pkt->soft) has already been copied from the card */
132 /* squeeze in an int for the cap encapsulation */
133
134 /* use these variables to be sure we count in bytes, not in
135 sizeof(struct archdr) */
136 pktbuf=(char*)pkt;
137 pkthdrbuf=(char*)pkthdr;
138 memcpy(pktbuf, pkthdrbuf, ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto));
139 memcpy(pktbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto)+sizeof(int),
140 pkthdrbuf+ARC_HDR_SIZE+sizeof(pkt->soft.cap.proto),
141 sizeof(struct archdr)-ARC_HDR_SIZE-sizeof(pkt->soft.cap.proto));
142
143 if (length > sizeof(pkt->soft))
144 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
145 pkt->soft.raw + sizeof(pkt->soft)
146 + sizeof(int),
147 length - sizeof(pkt->soft));
148
149 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
150
151 skb->protocol = __constant_htons(ETH_P_ARCNET);
152;
153 netif_rx(skb);
154 dev->last_rx = jiffies;
155}
156
157
158/*
159 * Create the ARCnet hard/soft headers for cap mode.
160 * There aren't any soft headers in cap mode - not even the protocol id.
161 */
162static int build_header(struct sk_buff *skb,
163 struct net_device *dev,
164 unsigned short type,
165 uint8_t daddr)
166{
167 int hdr_size = ARC_HDR_SIZE;
168 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
169
170 BUGMSG(D_PROTO, "Preparing header for cap packet %x.\n",
171 *((int*)&pkt->soft.cap.cookie[0]));
172 /*
173 * Set the source hardware address.
174 *
175 * This is pretty pointless for most purposes, but it can help in
176 * debugging. ARCnet does not allow us to change the source address in
177 * the actual packet sent)
178 */
179 pkt->hard.source = *dev->dev_addr;
180
181 /* see linux/net/ethernet/eth.c to see where I got the following */
182
183 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
184 /*
185 * FIXME: fill in the last byte of the dest ipaddr here to better
186 * comply with RFC1051 in "noarp" mode.
187 */
188 pkt->hard.dest = 0;
189 return hdr_size;
190 }
191 /* otherwise, just fill it in and go! */
192 pkt->hard.dest = daddr;
193
194 return hdr_size; /* success */
195}
196
197
198static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
199 int bufnum)
200{
201 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
202 struct arc_hardware *hard = &pkt->hard;
203 int ofs;
204
205
206 /* hard header is not included in packet length */
207 length -= ARC_HDR_SIZE;
208 /* And neither is the cookie field */
209 length -= sizeof(int);
210
211 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
212 lp->next_tx, lp->cur_tx, bufnum);
213
214 BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
215 *((int*)&pkt->soft.cap.cookie[0]));
216
217 if (length > XMTU) {
218 /* should never happen! other people already check for this. */
219 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n",
220 length, XMTU);
221 length = XMTU;
222 }
223 if (length > MinTU) {
224 hard->offset[0] = 0;
225 hard->offset[1] = ofs = 512 - length;
226 } else if (length > MTU) {
227 hard->offset[0] = 0;
228 hard->offset[1] = ofs = 512 - length - 3;
229 } else
230 hard->offset[0] = ofs = 256 - length;
231
232 BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n",
233 length,ofs);
234
235 // Copy the arcnet-header + the protocol byte down:
236 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
237 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
238 sizeof(pkt->soft.cap.proto));
239
240 // Skip the extra integer we have written into it as a cookie
241 // but write the rest of the message:
242 lp->hw.copy_to_card(dev, bufnum, ofs+1,
243 ((unsigned char*)&pkt->soft.cap.mes),length-1);
244
245 lp->lastload_dest = hard->dest;
246
247 return 1; /* done */
248}
249
250
251static int ack_tx(struct net_device *dev, int acked)
252{
253 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
254 struct sk_buff *ackskb;
255 struct archdr *ackpkt;
256 int length=sizeof(struct arc_cap);
257
258 BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
259 lp->outgoing.skb->protocol, acked);
260
261 BUGLVL(D_SKB) arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
262
263 /* Now alloc a skb to send back up through the layers: */
264 ackskb = alloc_skb(length + ARC_HDR_SIZE , GFP_ATOMIC);
265 if (ackskb == NULL) {
266 BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
267 goto free_outskb;
268 }
269
270 skb_put(ackskb, length + ARC_HDR_SIZE );
271 ackskb->dev = dev;
272
Arnaldo Carvalho de Melo459a98e2007-03-19 15:30:44 -0700273 skb_reset_mac_header(ackskb);
Arnaldo Carvalho de Melo98e399f2007-03-19 15:33:04 -0700274 ackpkt = (struct archdr *)skb_mac_header(ackskb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 /* skb_pull(ackskb, ARC_HDR_SIZE); */
276
277
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -0300278 skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
279 ARC_HDR_SIZE + sizeof(struct arc_cap));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 ackpkt->soft.cap.proto=0; /* using protocol 0 for acknowledge */
281 ackpkt->soft.cap.mes.ack=acked;
282
283 BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
284 *((int*)&ackpkt->soft.cap.cookie[0]));
285
286 ackskb->protocol = __constant_htons(ETH_P_ARCNET);
287
288 BUGLVL(D_SKB) arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
289 netif_rx(ackskb);
290
291 free_outskb:
292 dev_kfree_skb_irq(lp->outgoing.skb);
293 lp->outgoing.proto = NULL; /* We are always finished when in this protocol */
294
295 return 0;
296}