1/*
2 * Generic HDLC support routines for Linux
3 * HDLC Ethernet emulation support
4 *
5 * Copyright (C) 2002-2006 Krzysztof Halasa <khc@pm.waw.pl>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of version 2 of the GNU General Public License
9 * as published by the Free Software Foundation.
10 */
11
12#include <linux/errno.h>
13#include <linux/etherdevice.h>
14#include <linux/gfp.h>
15#include <linux/hdlc.h>
16#include <linux/if_arp.h>
17#include <linux/inetdevice.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/pkt_sched.h>
22#include <linux/poll.h>
23#include <linux/rtnetlink.h>
24#include <linux/skbuff.h>
25
26static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr);
27
28static netdev_tx_t eth_tx(struct sk_buff *skb, struct net_device *dev)
29{
30	int pad = ETH_ZLEN - skb->len;
31	if (pad > 0) {		/* Pad the frame with zeros */
32		int len = skb->len;
33		if (skb_tailroom(skb) < pad)
34			if (pskb_expand_head(skb, 0, pad, GFP_ATOMIC)) {
35				dev->stats.tx_dropped++;
36				dev_kfree_skb(skb);
37				return 0;
38			}
39		skb_put(skb, pad);
40		memset(skb->data + len, 0, pad);
41	}
42	return dev_to_hdlc(dev)->xmit(skb, dev);
43}
44
45
46static struct hdlc_proto proto = {
47	.type_trans	= eth_type_trans,
48	.xmit		= eth_tx,
49	.ioctl		= raw_eth_ioctl,
50	.module		= THIS_MODULE,
51};
52
53
54static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr)
55{
56	raw_hdlc_proto __user *raw_s = ifr->ifr_settings.ifs_ifsu.raw_hdlc;
57	const size_t size = sizeof(raw_hdlc_proto);
58	raw_hdlc_proto new_settings;
59	hdlc_device *hdlc = dev_to_hdlc(dev);
60	int result, old_qlen;
61
62	switch (ifr->ifr_settings.type) {
63	case IF_GET_PROTO:
64		if (dev_to_hdlc(dev)->proto != &proto)
65			return -EINVAL;
66		ifr->ifr_settings.type = IF_PROTO_HDLC_ETH;
67		if (ifr->ifr_settings.size < size) {
68			ifr->ifr_settings.size = size; /* data size wanted */
69			return -ENOBUFS;
70		}
71		if (copy_to_user(raw_s, hdlc->state, size))
72			return -EFAULT;
73		return 0;
74
75	case IF_PROTO_HDLC_ETH:
76		if (!capable(CAP_NET_ADMIN))
77			return -EPERM;
78
79		if (dev->flags & IFF_UP)
80			return -EBUSY;
81
82		if (copy_from_user(&new_settings, raw_s, size))
83			return -EFAULT;
84
85		if (new_settings.encoding == ENCODING_DEFAULT)
86			new_settings.encoding = ENCODING_NRZ;
87
88		if (new_settings.parity == PARITY_DEFAULT)
89			new_settings.parity = PARITY_CRC16_PR1_CCITT;
90
91		result = hdlc->attach(dev, new_settings.encoding,
92				      new_settings.parity);
93		if (result)
94			return result;
95
96		result = attach_hdlc_protocol(dev, &proto,
97					      sizeof(raw_hdlc_proto));
98		if (result)
99			return result;
100		memcpy(hdlc->state, &new_settings, size);
101		old_qlen = dev->tx_queue_len;
102		ether_setup(dev);
103		dev->tx_queue_len = old_qlen;
104		eth_hw_addr_random(dev);
105		netif_dormant_off(dev);
106		return 0;
107	}
108
109	return -EINVAL;
110}
111
112
113static int __init mod_init(void)
114{
115	register_hdlc_protocol(&proto);
116	return 0;
117}
118
119
120
121static void __exit mod_exit(void)
122{
123	unregister_hdlc_protocol(&proto);
124}
125
126
127module_init(mod_init);
128module_exit(mod_exit);
129
130MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
131MODULE_DESCRIPTION("Ethernet encapsulation support for generic HDLC");
132MODULE_LICENSE("GPL v2");
133