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 | |
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 | |
73 | static void __exit arcnet_rfc1051_exit(void) |
74 | { |
75 | arcnet_unregister_proto(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 | */ |
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, len: 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 */ |
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(size: length + ARC_HDR_SIZE, GFP_ATOMIC); |
137 | if (!skb) { |
138 | dev->stats.rx_dropped++; |
139 | return; |
140 | } |
141 | skb_put(skb, len: 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, desc: "rx" ); |
155 | |
156 | skb->protocol = type_trans(skb, dev); |
157 | netif_rx(skb); |
158 | } |
159 | |
160 | /* Create the ARCnet hard/soft headers for RFC1051 */ |
161 | static int (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, len: 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 | |
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 | |