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, 0, pad, GFP_ATOMIC)) { 32 dev->stats.tx_dropped++; 33 dev_kfree_skb(skb); 34 return 0; 35 } 36 skb_put(skb, 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(raw_s, hdlc->state, 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(&new_settings, raw_s, 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, 95 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(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); 116 return 0; 117 } 118 119 120 121 static void __exit hdlc_eth_exit(void) 122 { 123 unregister_hdlc_protocol(&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