1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * FDDI-type device handling.
8 *
9 * Version: @(#)fddi.c 1.0.0 08/12/96
10 *
11 * Authors: Lawrence V. Stefani, <stefani@lkg.dec.com>
12 *
13 * fddi.c is based on previous eth.c and tr.c work by
14 * Ross Biro
15 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
16 * Mark Evans, <evansmp@uhura.aston.ac.uk>
17 * Florian La Roche, <rzsfl@rz.uni-sb.de>
18 * Alan Cox, <gw4pts@gw4pts.ampr.org>
19 *
20 * Changes
21 * Alan Cox : New arp/rebuild header
22 * Maciej W. Rozycki : IPv6 support
23 */
24
25 #include <linux/module.h>
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/string.h>
29 #include <linux/mm.h>
30 #include <linux/socket.h>
31 #include <linux/in.h>
32 #include <linux/inet.h>
33 #include <linux/netdevice.h>
34 #include <linux/fddidevice.h>
35 #include <linux/if_ether.h>
36 #include <linux/skbuff.h>
37 #include <linux/errno.h>
38 #include <net/arp.h>
39 #include <net/sock.h>
40
41 /*
42 * Create the FDDI MAC header for an arbitrary protocol layer
43 *
44 * saddr=NULL means use device source address
45 * daddr=NULL means leave destination address (eg unresolved arp)
46 */
47
48 static int fddi_header(struct sk_buff *skb, struct net_device *dev,
49 unsigned short type,
50 const void *daddr, const void *saddr, unsigned int len)
51 {
52 int hl = FDDI_K_SNAP_HLEN;
53 struct fddihdr *fddi;
54
55 if(type != ETH_P_IP && type != ETH_P_IPV6 && type != ETH_P_ARP)
56 hl=FDDI_K_8022_HLEN-3;
57 fddi = skb_push(skb, hl);
58 fddi->fc = FDDI_FC_K_ASYNC_LLC_DEF;
59 if(type == ETH_P_IP || type == ETH_P_IPV6 || type == ETH_P_ARP)
60 {
61 fddi->hdr.llc_snap.dsap = FDDI_EXTENDED_SAP;
62 fddi->hdr.llc_snap.ssap = FDDI_EXTENDED_SAP;
63 fddi->hdr.llc_snap.ctrl = FDDI_UI_CMD;
64 fddi->hdr.llc_snap.oui[0] = 0x00;
65 fddi->hdr.llc_snap.oui[1] = 0x00;
66 fddi->hdr.llc_snap.oui[2] = 0x00;
67 fddi->hdr.llc_snap.ethertype = htons(type);
68 }
69
70 /* Set the source and destination hardware addresses */
71
72 if (saddr != NULL)
73 memcpy(fddi->saddr, saddr, dev->addr_len);
74 else
75 memcpy(fddi->saddr, dev->dev_addr, dev->addr_len);
76
77 if (daddr != NULL)
78 {
79 memcpy(fddi->daddr, daddr, dev->addr_len);
80 return hl;
81 }
82
83 return -hl;
84 }
85
86 /*
87 * Determine the packet's protocol ID and fill in skb fields.
88 * This routine is called before an incoming packet is passed
89 * up. It's used to fill in specific skb fields and to set
90 * the proper pointer to the start of packet data (skb->data).
91 */
92
93 __be16 fddi_type_trans(struct sk_buff *skb, struct net_device *dev)
94 {
95 struct fddihdr *fddi = (struct fddihdr *)skb->data;
96 __be16 type;
97
98 /*
99 * Set mac.raw field to point to FC byte, set data field to point
100 * to start of packet data. Assume 802.2 SNAP frames for now.
101 */
102
103 skb->dev = dev;
104 skb_reset_mac_header(skb); /* point to frame control (FC) */
105
106 if(fddi->hdr.llc_8022_1.dsap==0xe0)
107 {
108 skb_pull(skb, FDDI_K_8022_HLEN-3);
109 type = htons(ETH_P_802_2);
110 }
111 else
112 {
113 skb_pull(skb, FDDI_K_SNAP_HLEN); /* adjust for 21 byte header */
114 type=fddi->hdr.llc_snap.ethertype;
115 }
116
117 /* Set packet type based on destination address and flag settings */
118
119 if (*fddi->daddr & 0x01)
120 {
121 if (memcmp(fddi->daddr, dev->broadcast, FDDI_K_ALEN) == 0)
122 skb->pkt_type = PACKET_BROADCAST;
123 else
124 skb->pkt_type = PACKET_MULTICAST;
125 }
126
127 else if (dev->flags & IFF_PROMISC)
128 {
129 if (memcmp(fddi->daddr, dev->dev_addr, FDDI_K_ALEN))
130 skb->pkt_type = PACKET_OTHERHOST;
131 }
132
133 /* Assume 802.2 SNAP frames, for now */
134
135 return type;
136 }
137
138 EXPORT_SYMBOL(fddi_type_trans);
139
140 static const struct header_ops fddi_header_ops = {
141 .create = fddi_header,
142 };
143
144
145 static void fddi_setup(struct net_device *dev)
146 {
147 dev->header_ops = &fddi_header_ops;
148 dev->type = ARPHRD_FDDI;
149 dev->hard_header_len = FDDI_K_SNAP_HLEN+3; /* Assume 802.2 SNAP hdr len + 3 pad bytes */
150 dev->mtu = FDDI_K_SNAP_DLEN; /* Assume max payload of 802.2 SNAP frame */
151 dev->min_mtu = FDDI_K_SNAP_HLEN;
152 dev->max_mtu = FDDI_K_SNAP_DLEN;
153 dev->addr_len = FDDI_K_ALEN;
154 dev->tx_queue_len = 100; /* Long queues on FDDI */
155 dev->flags = IFF_BROADCAST | IFF_MULTICAST;
156
157 memset(dev->broadcast, 0xFF, FDDI_K_ALEN);
158 }
159
160 /**
161 * alloc_fddidev - Register FDDI device
162 * @sizeof_priv: Size of additional driver-private structure to be allocated
163 * for this FDDI device
164 *
165 * Fill in the fields of the device structure with FDDI-generic values.
166 *
167 * Constructs a new net device, complete with a private data area of
168 * size @sizeof_priv. A 32-byte (not bit) alignment is enforced for
169 * this private data area.
170 */
171 struct net_device *alloc_fddidev(int sizeof_priv)
172 {
173 return alloc_netdev(sizeof_priv, "fddi%d", NET_NAME_UNKNOWN,
174 fddi_setup);
175 }
176 EXPORT_SYMBOL(alloc_fddidev);
177
178 MODULE_LICENSE("GPL");