PageRenderTime 56ms CodeModel.GetById 12ms app.highlight 39ms RepoModel.GetById 2ms app.codeStats 0ms

/drivers/net/arcnet/capmode.c

http://github.com/mirrors/linux
C | 268 lines | 162 code | 48 blank | 58 comment | 18 complexity | 806feefb15fcc120bca257aac4c09c26 MD5 | raw file
  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_LICENSE("GPL");