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
27 #define pr_fmt(fmt) "arcnet:" KBUILD_MODNAME ": " fmt
28
29 #include <linux/module.h>
30 #include <linux/gfp.h>
31 #include <linux/init.h>
32 #include <linux/if_arp.h>
33 #include <net/arp.h>
34 #include <linux/netdevice.h>
35 #include <linux/skbuff.h>
36
37 #include "arcdevice.h"
38
39 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev);
40 static void rx(struct net_device *dev, int bufnum,
41 struct archdr *pkthdr, int length);
42 static int build_header(struct sk_buff *skb, struct net_device *dev,
43 unsigned short type, uint8_t daddr);
44 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
45 int bufnum);
46
47 static struct ArcProto rfc1051_proto = {
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
arcnet_rfc1051_init(void)58 static int __init arcnet_rfc1051_init(void)
59 {
60 pr_info("%s\n", "RFC1051 \"simple standard\" (`s') encapsulation support loaded");
61
62 arc_proto_map[ARC_P_IP_RFC1051]
63 = arc_proto_map[ARC_P_ARP_RFC1051]
64 = &rfc1051_proto;
65
66 /* if someone else already owns the broadcast, we won't take it */
67 if (arc_bcast_proto == arc_proto_default)
68 arc_bcast_proto = &rfc1051_proto;
69
70 return 0;
71 }
72
arcnet_rfc1051_exit(void)73 static void __exit arcnet_rfc1051_exit(void)
74 {
75 arcnet_unregister_proto(&rfc1051_proto);
76 }
77
78 module_init(arcnet_rfc1051_init);
79 module_exit(arcnet_rfc1051_exit);
80
81 MODULE_LICENSE("GPL");
82
83 /* Determine a packet's protocol ID.
84 *
85 * With ARCnet we have to convert everything to Ethernet-style stuff.
86 */
type_trans(struct sk_buff * skb,struct net_device * dev)87 static __be16 type_trans(struct sk_buff *skb, struct net_device *dev)
88 {
89 struct archdr *pkt = (struct archdr *)skb->data;
90 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
91 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
92
93 /* Pull off the arcnet header. */
94 skb_reset_mac_header(skb);
95 skb_pull(skb, hdr_size);
96
97 if (pkt->hard.dest == 0) {
98 skb->pkt_type = PACKET_BROADCAST;
99 } else if (dev->flags & IFF_PROMISC) {
100 /* if we're not sending to ourselves :) */
101 if (pkt->hard.dest != dev->dev_addr[0])
102 skb->pkt_type = PACKET_OTHERHOST;
103 }
104 /* now return the protocol number */
105 switch (soft->proto) {
106 case ARC_P_IP_RFC1051:
107 return htons(ETH_P_IP);
108 case ARC_P_ARP_RFC1051:
109 return htons(ETH_P_ARP);
110
111 default:
112 dev->stats.rx_errors++;
113 dev->stats.rx_crc_errors++;
114 return 0;
115 }
116
117 return htons(ETH_P_IP);
118 }
119
120 /* packet receiver */
rx(struct net_device * dev,int bufnum,struct archdr * pkthdr,int length)121 static void rx(struct net_device *dev, int bufnum,
122 struct archdr *pkthdr, int length)
123 {
124 struct arcnet_local *lp = netdev_priv(dev);
125 struct sk_buff *skb;
126 struct archdr *pkt = pkthdr;
127 int ofs;
128
129 arc_printk(D_DURING, dev, "it's a raw packet (length=%d)\n", length);
130
131 if (length >= MinTU)
132 ofs = 512 - length;
133 else
134 ofs = 256 - length;
135
136 skb = alloc_skb(length + ARC_HDR_SIZE, GFP_ATOMIC);
137 if (!skb) {
138 dev->stats.rx_dropped++;
139 return;
140 }
141 skb_put(skb, length + ARC_HDR_SIZE);
142 skb->dev = dev;
143
144 pkt = (struct archdr *)skb->data;
145
146 /* up to sizeof(pkt->soft) has already been copied from the card */
147 memcpy(pkt, pkthdr, sizeof(struct archdr));
148 if (length > sizeof(pkt->soft))
149 lp->hw.copy_from_card(dev, bufnum, ofs + sizeof(pkt->soft),
150 pkt->soft.raw + sizeof(pkt->soft),
151 length - sizeof(pkt->soft));
152
153 if (BUGLVL(D_SKB))
154 arcnet_dump_skb(dev, skb, "rx");
155
156 skb->protocol = type_trans(skb, dev);
157 netif_rx(skb);
158 }
159
160 /* Create the ARCnet hard/soft headers for RFC1051 */
build_header(struct sk_buff * skb,struct net_device * dev,unsigned short type,uint8_t daddr)161 static int build_header(struct sk_buff *skb, struct net_device *dev,
162 unsigned short type, uint8_t daddr)
163 {
164 int hdr_size = ARC_HDR_SIZE + RFC1051_HDR_SIZE;
165 struct archdr *pkt = skb_push(skb, hdr_size);
166 struct arc_rfc1051 *soft = &pkt->soft.rfc1051;
167
168 /* set the protocol ID according to RFC1051 */
169 switch (type) {
170 case ETH_P_IP:
171 soft->proto = ARC_P_IP_RFC1051;
172 break;
173 case ETH_P_ARP:
174 soft->proto = ARC_P_ARP_RFC1051;
175 break;
176 default:
177 arc_printk(D_NORMAL, dev, "RFC1051: I don't understand protocol %d (%Xh)\n",
178 type, type);
179 dev->stats.tx_errors++;
180 dev->stats.tx_aborted_errors++;
181 return 0;
182 }
183
184 /* Set the source hardware address.
185 *
186 * This is pretty pointless for most purposes, but it can help in
187 * debugging. ARCnet does not allow us to change the source address
188 * in the actual packet sent.
189 */
190 pkt->hard.source = *dev->dev_addr;
191
192 /* see linux/net/ethernet/eth.c to see where I got the following */
193
194 if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
195 /* FIXME: fill in the last byte of the dest ipaddr here to
196 * better comply with RFC1051 in "noarp" mode.
197 */
198 pkt->hard.dest = 0;
199 return hdr_size;
200 }
201 /* otherwise, just fill it in and go! */
202 pkt->hard.dest = daddr;
203
204 return hdr_size; /* success */
205 }
206
prepare_tx(struct net_device * dev,struct archdr * pkt,int length,int bufnum)207 static int prepare_tx(struct net_device *dev, struct archdr *pkt, int length,
208 int bufnum)
209 {
210 struct arcnet_local *lp = netdev_priv(dev);
211 struct arc_hardware *hard = &pkt->hard;
212 int ofs;
213
214 arc_printk(D_DURING, dev, "prepare_tx: txbufs=%d/%d/%d\n",
215 lp->next_tx, lp->cur_tx, bufnum);
216
217 /* hard header is not included in packet length */
218 length -= ARC_HDR_SIZE;
219
220 if (length > XMTU) {
221 /* should never happen! other people already check for this. */
222 arc_printk(D_NORMAL, dev, "Bug! prepare_tx with size %d (> %d)\n",
223 length, XMTU);
224 length = XMTU;
225 }
226 if (length > MinTU) {
227 hard->offset[0] = 0;
228 hard->offset[1] = ofs = 512 - length;
229 } else if (length > MTU) {
230 hard->offset[0] = 0;
231 hard->offset[1] = ofs = 512 - length - 3;
232 } else {
233 hard->offset[0] = ofs = 256 - length;
234 }
235
236 lp->hw.copy_to_card(dev, bufnum, 0, hard, ARC_HDR_SIZE);
237 lp->hw.copy_to_card(dev, bufnum, ofs, &pkt->soft, length);
238
239 lp->lastload_dest = hard->dest;
240
241 return 1; /* done */
242 }
243