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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{
Wang Chen454d7c92008-11-12 23:37:49 -0800106 struct arcnet_local *lp = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
155
156
157/*
158 * Create the ARCnet hard/soft headers for cap mode.
159 * There aren't any soft headers in cap mode - not even the protocol id.
160 */
161static int build_header(struct sk_buff *skb,
162 struct net_device *dev,
163 unsigned short type,
164 uint8_t daddr)
165{
166 int hdr_size = ARC_HDR_SIZE;
167 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
168
169 BUGMSG(D_PROTO, "Preparing header for cap packet %x.\n",
170 *((int*)&pkt->soft.cap.cookie[0]));
171 /*
172 * Set the source hardware address.
173 *
174 * This is pretty pointless for most purposes, but it can help in
175 * debugging. ARCnet does not allow us to change the source address in
176 * the actual packet sent)
177 */
178 pkt->hard.source = *dev->dev_addr;
179
180 /* see linux/net/ethernet/eth.c to see where I got the following */
181
182 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
183 /*
184 * FIXME: fill in the last byte of the dest ipaddr here to better
185 * comply with RFC1051 in "noarp" mode.
186 */
187 pkt->hard.dest = 0;
188 return hdr_size;
189 }
190 /* otherwise, just fill it in and go! */
191 pkt->hard.dest = daddr;
192
193 return hdr_size; /* success */
194}
195
196
197static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
198 int bufnum)
199{
Wang Chen454d7c92008-11-12 23:37:49 -0800200 struct arcnet_local *lp = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 struct arc_hardware *hard = &pkt->hard;
202 int ofs;
203
204
205 /* hard header is not included in packet length */
206 length -= ARC_HDR_SIZE;
207 /* And neither is the cookie field */
208 length -= sizeof(int);
209
210 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
211 lp->next_tx, lp->cur_tx, bufnum);
212
213 BUGMSG(D_PROTO, "Sending for cap packet %x.\n",
214 *((int*)&pkt->soft.cap.cookie[0]));
215
216 if (length > XMTU) {
217 /* should never happen! other people already check for this. */
218 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n",
219 length, XMTU);
220 length = XMTU;
221 }
222 if (length > MinTU) {
223 hard->offset[0] = 0;
224 hard->offset[1] = ofs = 512 - length;
225 } else if (length > MTU) {
226 hard->offset[0] = 0;
227 hard->offset[1] = ofs = 512 - length - 3;
228 } else
229 hard->offset[0] = ofs = 256 - length;
230
231 BUGMSG(D_DURING, "prepare_tx: length=%d ofs=%d\n",
232 length,ofs);
233
234 // Copy the arcnet-header + the protocol byte down:
235 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
236 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft.cap.proto,
237 sizeof(pkt->soft.cap.proto));
238
239 // Skip the extra integer we have written into it as a cookie
240 // but write the rest of the message:
241 lp->hw.copy_to_card(dev, bufnum, ofs+1,
242 ((unsigned char*)&pkt->soft.cap.mes),length-1);
243
244 lp->lastload_dest = hard->dest;
245
246 return 1; /* done */
247}
248
249
250static int ack_tx(struct net_device *dev, int acked)
251{
Wang Chen454d7c92008-11-12 23:37:49 -0800252 struct arcnet_local *lp = netdev_priv(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 struct sk_buff *ackskb;
254 struct archdr *ackpkt;
255 int length=sizeof(struct arc_cap);
256
257 BUGMSG(D_DURING, "capmode: ack_tx: protocol: %x: result: %d\n",
258 lp->outgoing.skb->protocol, acked);
259
260 BUGLVL(D_SKB) arcnet_dump_skb(dev, lp->outgoing.skb, "ack_tx");
261
262 /* Now alloc a skb to send back up through the layers: */
263 ackskb = alloc_skb(length + ARC_HDR_SIZE , GFP_ATOMIC);
264 if (ackskb == NULL) {
265 BUGMSG(D_NORMAL, "Memory squeeze, can't acknowledge.\n");
266 goto free_outskb;
267 }
268
269 skb_put(ackskb, length + ARC_HDR_SIZE );
270 ackskb->dev = dev;
271
Arnaldo Carvalho de Melo459a98e2007-03-19 15:30:44 -0700272 skb_reset_mac_header(ackskb);
Arnaldo Carvalho de Melo98e399f2007-03-19 15:33:04 -0700273 ackpkt = (struct archdr *)skb_mac_header(ackskb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 /* skb_pull(ackskb, ARC_HDR_SIZE); */
275
276
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -0300277 skb_copy_from_linear_data(lp->outgoing.skb, ackpkt,
278 ARC_HDR_SIZE + sizeof(struct arc_cap));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 ackpkt->soft.cap.proto=0; /* using protocol 0 for acknowledge */
280 ackpkt->soft.cap.mes.ack=acked;
281
282 BUGMSG(D_PROTO, "Ackknowledge for cap packet %x.\n",
283 *((int*)&ackpkt->soft.cap.cookie[0]));
284
285 ackskb->protocol = __constant_htons(ETH_P_ARCNET);
286
287 BUGLVL(D_SKB) arcnet_dump_skb(dev, ackskb, "ack_tx_recv");
288 netif_rx(ackskb);
289
290 free_outskb:
291 dev_kfree_skb_irq(lp->outgoing.skb);
292 lp->outgoing.proto = NULL; /* We are always finished when in this protocol */
293
294 return 0;
295}