1 /*
2 * Linux ARCnet driver - RFC1051 ("simple" standard) packet encapsulation
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 #include <linux/module.h>
27 #include <linux/init.h>
28 #include <linux/if_arp.h>
29 #include <net/arp.h>
30 #include <linux/netdevice.h>
31 #include <linux/skbuff.h>
32 #include <linux/arcdevice.h>
33
34 #define VERSION "arcnet: RFC1051 \"simple standard\" (`s') encapsulation support loaded.\n"
35
36
37 static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev);
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 rfc1051_proto =
47 {
48 .suffix = 's',
49 .mtu = XMTU - RFC1051_HDR_SIZE,
50 .is_ip = 1,
51 .rx = rx,
52 .build_header = build_header,
53 .prepare_tx = prepare_tx,
54 .continue_tx = NULL,
55 .ack_tx = NULL
56 };
57
58
59 static int __init arcnet_rfc1051_init(void)
60 {
61 printk(VERSION);
62
63 arc_proto_map[ARC_P_IP_RFC1051]
64 = arc_proto_map[ARC_P_ARP_RFC1051]
65 = &rfc1051_proto;
66
67 /* if someone else already owns the broadcast, we won't take it */
68 if (arc_bcast_proto == arc_proto_default)
69 arc_bcast_proto = &rfc1051_proto;
70
71 return 0;
72 }
73
74 static void __exit arcnet_rfc1051_exit(void)
75 {
76 arcnet_unregister_proto(&rfc1051_proto);
77 }
78
79 module_init(arcnet_rfc1051_init);
80 module_exit(arcnet_rfc1051_exit);
81
82 MODULE_LICENSE("GPL");
83
84 /*
85 * Determine a packet's protocol ID.
86 *
87 * With ARCnet we have to convert everything to Ethernet-style stuff.
88 */
89 static unsigned short type_trans(struct sk_buff *skb, struct net_device *dev)
90 {
91 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
92 struct archdr *pkt = (struct archdr *) skb->data;
93 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
94 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
95
96 /* Pull off the arcnet header. */
97 skb->mac.raw = skb->data;
98 skb_pull(skb, hdr_size);
99
100 if (pkt->hard.dest == 0)
101 skb->pkt_type = PACKET_BROADCAST;
102 else if (dev->flags & IFF_PROMISC) {
103 /* if we're not sending to ourselves :) */
104 if (pkt->hard.dest != dev->dev_addr[0])
105 skb->pkt_type = PACKET_OTHERHOST;
106 }
107 /* now return the protocol number */
108 switch (soft->proto) {
109 case ARC_P_IP_RFC1051:
110 return htons(ETH_P_IP);
111 case ARC_P_ARP_RFC1051:
112 return htons(ETH_P_ARP);
113
114 default:
115 lp->stats.rx_errors++;
116 lp->stats.rx_crc_errors++;
117 return 0;
118 }
119
120 return htons(ETH_P_IP);
121 }
122
123
124 /* packet receiver */
125 static void rx(struct net_device *dev, int bufnum,
126 struct archdr *pkthdr, int length)
127 {
128 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
129 struct sk_buff *skb;
130 struct archdr *pkt = pkthdr;
131 int ofs;
132
133 BUGMSG(D_DURING, "it's a raw packet (length=%d)\n", length);
134
135 if (length >= MinTU)
136 ofs = 512 - length;
137 else
138 ofs = 256 - length;
139
140 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
141 if (skb == NULL) {
142 BUGMSG(D_NORMAL, "Memory squeeze, dropping packet.\n");
143 lp->stats.rx_dropped++;
144 return;
145 }
146 skb_put(skb, length + ARC_HDR_SIZE);
147 skb->dev = dev;
148
149 pkt = (struct archdr *) skb->data;
150
151 /* up to sizeof(pkt->soft) has already been copied from the card */
152 memcpy(pkt, pkthdr, sizeof(struct archdr));
153 if (length > sizeof(pkt->soft))
154 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
155 pkt->soft.raw + sizeof(pkt->soft),
156 length - sizeof(pkt->soft));
157
158 BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "rx");
159
160 skb->protocol = type_trans(skb, dev);
161 netif_rx(skb);
162 dev->last_rx = jiffies;
163 }
164
165
166 /*
167 * Create the ARCnet hard/soft headers for RFC1051.
168 */
169 static int build_header(struct sk_buff *skb, struct net_device *dev,
170 unsigned short type, uint8_t daddr)
171 {
172 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
173 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
174 struct archdr *pkt = (struct archdr *) skb_push(skb, hdr_size);
175 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
176
177 /* set the protocol ID according to RFC1051 */
178 switch (type) {
179 case ETH_P_IP:
180 soft->proto = ARC_P_IP_RFC1051;
181 break;
182 case ETH_P_ARP:
183 soft->proto = ARC_P_ARP_RFC1051;
184 break;
185 default:
186 BUGMSG(D_NORMAL, "RFC1051: I don't understand protocol %d (%Xh)\n",
187 type, type);
188 lp->stats.tx_errors++;
189 lp->stats.tx_aborted_errors++;
190 return 0;
191 }
192
193
194 /*
195 * Set the source hardware address.
196 *
197 * This is pretty pointless for most purposes, but it can help in
198 * debugging. ARCnet does not allow us to change the source address in
199 * the actual packet sent)
200 */
201 pkt->hard.source = *dev->dev_addr;
202
203 /* see linux/net/ethernet/eth.c to see where I got the following */
204
205 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
206 /*
207 * FIXME: fill in the last byte of the dest ipaddr here to better
208 * comply with RFC1051 in "noarp" mode.
209 */
210 pkt->hard.dest = 0;
211 return hdr_size;
212 }
213 /* otherwise, just fill it in and go! */
214 pkt->hard.dest = daddr;
215
216 return hdr_size; /* success */
217 }
218
219
220 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
221 int bufnum)
222 {
223 struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
224 struct arc_hardware *hard = &pkt->hard;
225 int ofs;
226
227 BUGMSG(D_DURING, "prepare_tx: txbufs=%d/%d/%d\n",
228 lp->next_tx, lp->cur_tx, bufnum);
229
230 length -= ARC_HDR_SIZE; /* hard header is not included in packet length */
231
232 if (length > XMTU) {
233 /* should never happen! other people already check for this. */
234 BUGMSG(D_NORMAL, "Bug! prepare_tx with size %d (> %d)\n",
235 length, XMTU);
236 length = XMTU;
237 }
238 if (length > MinTU) {
239 hard->offset[0] = 0;
240 hard->offset[1] = ofs = 512 - length;
241 } else if (length > MTU) {
242 hard->offset[0] = 0;
243 hard->offset[1] = ofs = 512 - length - 3;
244 } else
245 hard->offset[0] = ofs = 256 - length;
246
247 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
248 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length);
249
250 lp->lastload_dest = hard->dest;
251
252 return 1; /* done */
253 }
254
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