xref: /openbmc/linux/net/802/hippi.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		HIPPI-type device handling.
7  *
8  * Version:	@(#)hippi.c	1.0.0	05/29/97
9  *
10  * Authors:	Ross Biro
11  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12  *		Mark Evans, <evansmp@uhura.aston.ac.uk>
13  *		Florian  La Roche, <rzsfl@rz.uni-sb.de>
14  *		Alan Cox, <gw4pts@gw4pts.ampr.org>
15  *		Jes Sorensen, <Jes.Sorensen@cern.ch>
16  *
17  *		This program is free software; you can redistribute it and/or
18  *		modify it under the terms of the GNU General Public License
19  *		as published by the Free Software Foundation; either version
20  *		2 of the License, or (at your option) any later version.
21  */
22 
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/string.h>
28 #include <linux/mm.h>
29 #include <linux/socket.h>
30 #include <linux/in.h>
31 #include <linux/inet.h>
32 #include <linux/netdevice.h>
33 #include <linux/hippidevice.h>
34 #include <linux/skbuff.h>
35 #include <linux/errno.h>
36 #include <net/arp.h>
37 #include <net/sock.h>
38 #include <asm/uaccess.h>
39 #include <asm/checksum.h>
40 #include <asm/system.h>
41 
42 /*
43  * Create the HIPPI MAC header for an arbitrary protocol layer
44  *
45  * saddr=NULL	means use device source address
46  * daddr=NULL	means leave destination address (eg unresolved arp)
47  */
48 
49 static int hippi_header(struct sk_buff *skb, struct net_device *dev,
50 			unsigned short type, void *daddr, void *saddr,
51 			unsigned len)
52 {
53 	struct hippi_hdr *hip = (struct hippi_hdr *)skb_push(skb, HIPPI_HLEN);
54 	struct hippi_cb *hcb = (struct hippi_cb *) skb->cb;
55 
56 	if (!len){
57 		len = skb->len - HIPPI_HLEN;
58 		printk("hippi_header(): length not supplied\n");
59 	}
60 
61 	/*
62 	 * Due to the stupidity of the little endian byte-order we
63 	 * have to set the fp field this way.
64 	 */
65 	hip->fp.fixed		= __constant_htonl(0x04800018);
66 	hip->fp.d2_size		= htonl(len + 8);
67 	hip->le.fc		= 0;
68 	hip->le.double_wide	= 0;	/* only HIPPI 800 for the time being */
69 	hip->le.message_type	= 0;	/* Data PDU */
70 
71 	hip->le.dest_addr_type	= 2;	/* 12 bit SC address */
72 	hip->le.src_addr_type	= 2;	/* 12 bit SC address */
73 
74 	memcpy(hip->le.src_switch_addr, dev->dev_addr + 3, 3);
75 	memset(&hip->le.reserved, 0, 16);
76 
77 	hip->snap.dsap		= HIPPI_EXTENDED_SAP;
78 	hip->snap.ssap		= HIPPI_EXTENDED_SAP;
79 	hip->snap.ctrl		= HIPPI_UI_CMD;
80 	hip->snap.oui[0]	= 0x00;
81 	hip->snap.oui[1]	= 0x00;
82 	hip->snap.oui[2]	= 0x00;
83 	hip->snap.ethertype	= htons(type);
84 
85 	if (daddr)
86 	{
87 		memcpy(hip->le.dest_switch_addr, daddr + 3, 3);
88 		memcpy(&hcb->ifield, daddr + 2, 4);
89 		return HIPPI_HLEN;
90 	}
91 	hcb->ifield = 0;
92 	return -((int)HIPPI_HLEN);
93 }
94 
95 
96 /*
97  * Rebuild the HIPPI MAC header. This is called after an ARP has
98  * completed on this sk_buff. We now let ARP fill in the other fields.
99  */
100 
101 static int hippi_rebuild_header(struct sk_buff *skb)
102 {
103 	struct hippi_hdr *hip = (struct hippi_hdr *)skb->data;
104 
105 	/*
106 	 * Only IP is currently supported
107 	 */
108 
109 	if(hip->snap.ethertype != __constant_htons(ETH_P_IP))
110 	{
111 		printk(KERN_DEBUG "%s: unable to resolve type %X addresses.\n",skb->dev->name,ntohs(hip->snap.ethertype));
112 		return 0;
113 	}
114 
115 	/*
116 	 * We don't support dynamic ARP on HIPPI, but we use the ARP
117 	 * static ARP tables to hold the I-FIELDs.
118 	 */
119 	return arp_find(hip->le.daddr, skb);
120 }
121 
122 
123 /*
124  *	Determine the packet's protocol ID.
125  */
126 
127 __be16 hippi_type_trans(struct sk_buff *skb, struct net_device *dev)
128 {
129 	struct hippi_hdr *hip;
130 
131 	hip = (struct hippi_hdr *) skb->data;
132 
133 	/*
134 	 * This is actually wrong ... question is if we really should
135 	 * set the raw address here.
136 	 */
137 	 skb->mac.raw = skb->data;
138 	 skb_pull(skb, HIPPI_HLEN);
139 
140 	/*
141 	 * No fancy promisc stuff here now.
142 	 */
143 
144 	return hip->snap.ethertype;
145 }
146 
147 EXPORT_SYMBOL(hippi_type_trans);
148 
149 static int hippi_change_mtu(struct net_device *dev, int new_mtu)
150 {
151 	/*
152 	 * HIPPI's got these nice large MTUs.
153 	 */
154 	if ((new_mtu < 68) || (new_mtu > 65280))
155 		return -EINVAL;
156 	dev->mtu = new_mtu;
157 	return(0);
158 }
159 
160 /*
161  * For HIPPI we will actually use the lower 4 bytes of the hardware
162  * address as the I-FIELD rather than the actual hardware address.
163  */
164 static int hippi_mac_addr(struct net_device *dev, void *p)
165 {
166 	struct sockaddr *addr = p;
167 	if (netif_running(dev))
168 		return -EBUSY;
169 	memcpy(dev->dev_addr, addr->sa_data, dev->addr_len);
170 	return 0;
171 }
172 
173 static int hippi_neigh_setup_dev(struct net_device *dev, struct neigh_parms *p)
174 {
175 	/* Never send broadcast/multicast ARP messages */
176 	p->mcast_probes = 0;
177 
178 	/* In IPv6 unicast probes are valid even on NBMA,
179 	* because they are encapsulated in normal IPv6 protocol.
180 	* Should be a generic flag.
181 	*/
182 	if (p->tbl->family != AF_INET6)
183 		p->ucast_probes = 0;
184 	return 0;
185 }
186 
187 static void hippi_setup(struct net_device *dev)
188 {
189 	dev->set_multicast_list		= NULL;
190 	dev->change_mtu			= hippi_change_mtu;
191 	dev->hard_header		= hippi_header;
192 	dev->rebuild_header 		= hippi_rebuild_header;
193 	dev->set_mac_address 		= hippi_mac_addr;
194 	dev->hard_header_parse		= NULL;
195 	dev->hard_header_cache		= NULL;
196 	dev->header_cache_update	= NULL;
197 	dev->neigh_setup 		= hippi_neigh_setup_dev;
198 
199 	/*
200 	 * We don't support HIPPI `ARP' for the time being, and probably
201 	 * never will unless someone else implements it. However we
202 	 * still need a fake ARPHRD to make ifconfig and friends play ball.
203 	 */
204 	dev->type		= ARPHRD_HIPPI;
205 	dev->hard_header_len 	= HIPPI_HLEN;
206 	dev->mtu		= 65280;
207 	dev->addr_len		= HIPPI_ALEN;
208 	dev->tx_queue_len	= 25 /* 5 */;
209 	memset(dev->broadcast, 0xFF, HIPPI_ALEN);
210 
211 
212 	/*
213 	 * HIPPI doesn't support broadcast+multicast and we only use
214 	 * static ARP tables. ARP is disabled by hippi_neigh_setup_dev.
215 	 */
216 	dev->flags = 0;
217 }
218 
219 /**
220  * alloc_hippi_dev - Register HIPPI device
221  * @sizeof_priv: Size of additional driver-private structure to be allocated
222  *	for this HIPPI device
223  *
224  * Fill in the fields of the device structure with HIPPI-generic values.
225  *
226  * Constructs a new net device, complete with a private data area of
227  * size @sizeof_priv.  A 32-byte (not bit) alignment is enforced for
228  * this private data area.
229  */
230 
231 struct net_device *alloc_hippi_dev(int sizeof_priv)
232 {
233 	return alloc_netdev(sizeof_priv, "hip%d", hippi_setup);
234 }
235 
236 EXPORT_SYMBOL(alloc_hippi_dev);
237