1 /*
2 * Linux ARCnet driver - "raw mode" packet encapsulation (no soft headers)
3 *
4 * Written 1994-1999 by Avery Pennarun.
5 * Derived from skeleton.c by Donald Becker.
6 *
7 * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
8 * for sponsoring the further development of this driver.
9 *
10 * **********************
11 *
12 * The original copyright of skeleton.c was as follows:
13 *
14 * skeleton.c Written 1993 by Donald Becker.
15 * Copyright 1993 United States Government as represented by the
16 * Director, National Security Agency. This software may only be used
17 * and distributed according to the terms of the GNU General Public License as
18 * modified by SRC, incorporated herein by reference.
19 *
20 * **********************
21 *
22 * For more details, see drivers/net/arcnet.c
23 *
24 * **********************
25 */
26
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/if_arp.h>
30 #include <net/arp.h>
31 #include <linux/netdevice.h>
32 #include <linux/skbuff.h>
33 #include <linux/arcdevice.h>
34
35 #define VERSION "arcnet: raw mode (`r') encapsulation support loaded.\n"
36
37
38 static void rx(struct net_device *dev, int bufnum,
39 struct archdr *pkthdr, int length);
40 static int build_header(struct sk_buff *skb, struct net_device *dev,
41 unsigned short type, uint8_t daddr);
42 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
43 int bufnum);
44
45
46 struct ArcProto rawmode_proto =
47 {
48 'r',
49 XMTU,
50 rx,
51 build_header,
52 prepare_tx
53 };
54
55
arcnet_raw_init(void)56 void arcnet_raw_init(void)
57 {
58 int count;
59
60 for (count = 0; count < 256; count++)
61 if (arc_proto_map[count] == arc_proto_default)
62 arc_proto_map[count] = &rawmode_proto;
63
64 /* for raw mode, we only set the bcast proto if there's no better one */
65 if (arc_bcast_proto == arc_proto_default)
66 arc_bcast_proto = &rawmode_proto;
67
68 arc_proto_default = &rawmode_proto;
69 }
70
71
72 #ifdef MODULE
73
init_module(void)74 int __init init_module(void)
75 {
76 printk(VERSION);
77 arcnet_raw_init();
78 return 0;
79 }
80
cleanup_module(void)81 void cleanup_module(void)
82 {
83 arcnet_unregister_proto(&rawmode_proto);
84 }
85
86 MODULE_LICENSE("GPL");
87 #endif /* MODULE */
88
89
90
91 /* packet receiver */
rx(struct net_device * dev,int bufnum,struct archdr * pkthdr,int length)92 static void rx(struct net_device *dev, int bufnum,
93 struct archdr *pkthdr, int length)
94 {
95 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
96 struct sk_buff *skb;
97 struct archdr *pkt = pkthdr;
98 int ofs;
99
100 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length);
101
102 if (length >= MinTU)
103 ofs = 512 - length;
104 else
105 ofs = 256 - length;
106
107 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
108 if (skb == NULL) {
109 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
110 lp->stats.rx_dropped++;
111 return;
112 }
113 skb_put(skb, length + ARC_HDR_SIZE);
114 skb->dev = dev;
115
116 pkt = (struct archdr *) skb->data;
117
118 skb->mac.raw = skb->data;
119 skb_pull(skb, ARC_HDR_SIZE);
120
121 /* up to sizeof(pkt->soft) has already been copied from the card */
122 memcpy(pkt, pkthdr, sizeof(struct archdr));
123 if (length > sizeof(pkt->soft))
124 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
125 pkt->soft.raw + sizeof(pkt->soft),
126 length - sizeof(pkt->soft));
127
128 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
129
130 skb->protocol = 0;
131 netif_rx(skb);
132 dev->last_rx = jiffies;
133 }
134
135
136 /*
137 * Create the ARCnet hard/soft headers for raw mode.
138 * There aren't any soft headers in raw mode - not even the protocol id.
139 */
build_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,uint8_t daddr)140 static int build_header(struct sk_buff *skb, struct net_device *dev,
141 unsigned short type, uint8_t daddr)
142 {
143 int hdr_size = ARC_HDR_SIZE;
144 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
145
146 /*
147 * Set the source hardware address.
148 *
149 * This is pretty pointless for most purposes, but it can help in
150 * debugging. ARCnet does not allow us to change the source address in
151 * the actual packet sent)
152 */
153 pkt->hard.source = *dev->dev_addr;
154
155 /* see linux/net/ethernet/eth.c to see where I got the following */
156
157 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
158 /*
159 * FIXME: fill in the last byte of the dest ipaddr here to better
160 * comply with RFC1051 in "noarp" mode.
161 */
162 pkt->hard.dest = 0;
163 return hdr_size;
164 }
165 /* otherwise, just fill it in and go! */
166 pkt->hard.dest = daddr;
167
168 return hdr_size; /* success */
169 }
170
171
prepare_tx(struct net_device * dev,struct archdr * pkt,int length,int bufnum)172 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
173 int bufnum)
174 {
175 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
176 struct arc_hardware *hard = &pkt->hard;
177 int ofs;
178
179 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
180 lp->next_tx, lp->cur_tx, bufnum);
181
182 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
183
184 if (length > XMTU) {
185 /* should never happen! other people already check for this. */
186 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n",
187 length, XMTU);
188 length = XMTU;
189 }
190 if (length > MinTU) {
191 hard->offset[0] = 0;
192 hard->offset[1] = ofs = 512 - length;
193 } else if (length > MTU) {
194 hard->offset[0] = 0;
195 hard->offset[1] = ofs = 512 - length - 3;
196 } else
197 hard->offset[0] = ofs = 256 - length;
198
199 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
200 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length);
201
202 lp->lastload_dest = hard->dest;
203
204 return 1; /* done */
205 }
206