1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Generic HDLC support routines for Linux
4*4882a593Smuzhiyun * HDLC Ethernet emulation support
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Copyright (C) 2002-2006 Krzysztof Halasa <khc@pm.waw.pl>
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <linux/errno.h>
10*4882a593Smuzhiyun #include <linux/etherdevice.h>
11*4882a593Smuzhiyun #include <linux/gfp.h>
12*4882a593Smuzhiyun #include <linux/hdlc.h>
13*4882a593Smuzhiyun #include <linux/if_arp.h>
14*4882a593Smuzhiyun #include <linux/inetdevice.h>
15*4882a593Smuzhiyun #include <linux/init.h>
16*4882a593Smuzhiyun #include <linux/kernel.h>
17*4882a593Smuzhiyun #include <linux/module.h>
18*4882a593Smuzhiyun #include <linux/pkt_sched.h>
19*4882a593Smuzhiyun #include <linux/poll.h>
20*4882a593Smuzhiyun #include <linux/rtnetlink.h>
21*4882a593Smuzhiyun #include <linux/skbuff.h>
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr);
24*4882a593Smuzhiyun
eth_tx(struct sk_buff * skb,struct net_device * dev)25*4882a593Smuzhiyun static netdev_tx_t eth_tx(struct sk_buff *skb, struct net_device *dev)
26*4882a593Smuzhiyun {
27*4882a593Smuzhiyun int pad = ETH_ZLEN - skb->len;
28*4882a593Smuzhiyun if (pad > 0) { /* Pad the frame with zeros */
29*4882a593Smuzhiyun int len = skb->len;
30*4882a593Smuzhiyun if (skb_tailroom(skb) < pad)
31*4882a593Smuzhiyun if (pskb_expand_head(skb, 0, pad, GFP_ATOMIC)) {
32*4882a593Smuzhiyun dev->stats.tx_dropped++;
33*4882a593Smuzhiyun dev_kfree_skb(skb);
34*4882a593Smuzhiyun return 0;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun skb_put(skb, pad);
37*4882a593Smuzhiyun memset(skb->data + len, 0, pad);
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun return dev_to_hdlc(dev)->xmit(skb, dev);
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun static struct hdlc_proto proto = {
44*4882a593Smuzhiyun .type_trans = eth_type_trans,
45*4882a593Smuzhiyun .xmit = eth_tx,
46*4882a593Smuzhiyun .ioctl = raw_eth_ioctl,
47*4882a593Smuzhiyun .module = THIS_MODULE,
48*4882a593Smuzhiyun };
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun
raw_eth_ioctl(struct net_device * dev,struct ifreq * ifr)51*4882a593Smuzhiyun static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr)
52*4882a593Smuzhiyun {
53*4882a593Smuzhiyun raw_hdlc_proto __user *raw_s = ifr->ifr_settings.ifs_ifsu.raw_hdlc;
54*4882a593Smuzhiyun const size_t size = sizeof(raw_hdlc_proto);
55*4882a593Smuzhiyun raw_hdlc_proto new_settings;
56*4882a593Smuzhiyun hdlc_device *hdlc = dev_to_hdlc(dev);
57*4882a593Smuzhiyun unsigned int old_qlen;
58*4882a593Smuzhiyun int result;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun switch (ifr->ifr_settings.type) {
61*4882a593Smuzhiyun case IF_GET_PROTO:
62*4882a593Smuzhiyun if (dev_to_hdlc(dev)->proto != &proto)
63*4882a593Smuzhiyun return -EINVAL;
64*4882a593Smuzhiyun ifr->ifr_settings.type = IF_PROTO_HDLC_ETH;
65*4882a593Smuzhiyun if (ifr->ifr_settings.size < size) {
66*4882a593Smuzhiyun ifr->ifr_settings.size = size; /* data size wanted */
67*4882a593Smuzhiyun return -ENOBUFS;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun if (copy_to_user(raw_s, hdlc->state, size))
70*4882a593Smuzhiyun return -EFAULT;
71*4882a593Smuzhiyun return 0;
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun case IF_PROTO_HDLC_ETH:
74*4882a593Smuzhiyun if (!capable(CAP_NET_ADMIN))
75*4882a593Smuzhiyun return -EPERM;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun if (dev->flags & IFF_UP)
78*4882a593Smuzhiyun return -EBUSY;
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun if (copy_from_user(&new_settings, raw_s, size))
81*4882a593Smuzhiyun return -EFAULT;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun if (new_settings.encoding == ENCODING_DEFAULT)
84*4882a593Smuzhiyun new_settings.encoding = ENCODING_NRZ;
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun if (new_settings.parity == PARITY_DEFAULT)
87*4882a593Smuzhiyun new_settings.parity = PARITY_CRC16_PR1_CCITT;
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun result = hdlc->attach(dev, new_settings.encoding,
90*4882a593Smuzhiyun new_settings.parity);
91*4882a593Smuzhiyun if (result)
92*4882a593Smuzhiyun return result;
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun result = attach_hdlc_protocol(dev, &proto,
95*4882a593Smuzhiyun sizeof(raw_hdlc_proto));
96*4882a593Smuzhiyun if (result)
97*4882a593Smuzhiyun return result;
98*4882a593Smuzhiyun memcpy(hdlc->state, &new_settings, size);
99*4882a593Smuzhiyun old_qlen = dev->tx_queue_len;
100*4882a593Smuzhiyun ether_setup(dev);
101*4882a593Smuzhiyun dev->tx_queue_len = old_qlen;
102*4882a593Smuzhiyun dev->priv_flags &= ~IFF_TX_SKB_SHARING;
103*4882a593Smuzhiyun eth_hw_addr_random(dev);
104*4882a593Smuzhiyun call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
105*4882a593Smuzhiyun netif_dormant_off(dev);
106*4882a593Smuzhiyun return 0;
107*4882a593Smuzhiyun }
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun return -EINVAL;
110*4882a593Smuzhiyun }
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun
mod_init(void)113*4882a593Smuzhiyun static int __init mod_init(void)
114*4882a593Smuzhiyun {
115*4882a593Smuzhiyun register_hdlc_protocol(&proto);
116*4882a593Smuzhiyun return 0;
117*4882a593Smuzhiyun }
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun
120*4882a593Smuzhiyun
mod_exit(void)121*4882a593Smuzhiyun static void __exit mod_exit(void)
122*4882a593Smuzhiyun {
123*4882a593Smuzhiyun unregister_hdlc_protocol(&proto);
124*4882a593Smuzhiyun }
125*4882a593Smuzhiyun
126*4882a593Smuzhiyun
127*4882a593Smuzhiyun module_init(mod_init);
128*4882a593Smuzhiyun module_exit(mod_exit);
129*4882a593Smuzhiyun
130*4882a593Smuzhiyun MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
131*4882a593Smuzhiyun MODULE_DESCRIPTION("Ethernet encapsulation support for generic HDLC");
132*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
133