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