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![Andrew Lunn](/assets/img/avatar_default.png)
An HDLC device can change type when the protocol driver is changed. Calling the notifier change allows potential users of the interface know about this planned change, and even block it. After the change has occurred, send a second notification to users can evaluate the new device type etc. Signed-off-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
244 lines
4.9 KiB
C
244 lines
4.9 KiB
C
/*
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* Generic HDLC support routines for Linux
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* X.25 support
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*
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* Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2 of the GNU General Public License
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* as published by the Free Software Foundation.
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*/
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#include <linux/errno.h>
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#include <linux/gfp.h>
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#include <linux/hdlc.h>
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#include <linux/if_arp.h>
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#include <linux/inetdevice.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/lapb.h>
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#include <linux/module.h>
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#include <linux/pkt_sched.h>
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#include <linux/poll.h>
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#include <linux/rtnetlink.h>
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#include <linux/skbuff.h>
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#include <net/x25device.h>
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static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
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/* These functions are callbacks called by LAPB layer */
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static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
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{
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struct sk_buff *skb;
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unsigned char *ptr;
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if ((skb = dev_alloc_skb(1)) == NULL) {
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netdev_err(dev, "out of memory\n");
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return;
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}
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ptr = skb_put(skb, 1);
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*ptr = code;
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skb->protocol = x25_type_trans(skb, dev);
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netif_rx(skb);
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}
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static void x25_connected(struct net_device *dev, int reason)
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{
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x25_connect_disconnect(dev, reason, X25_IFACE_CONNECT);
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}
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static void x25_disconnected(struct net_device *dev, int reason)
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{
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x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT);
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}
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static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
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{
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unsigned char *ptr;
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skb_push(skb, 1);
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if (skb_cow(skb, 1))
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return NET_RX_DROP;
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ptr = skb->data;
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*ptr = X25_IFACE_DATA;
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skb->protocol = x25_type_trans(skb, dev);
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return netif_rx(skb);
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}
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static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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hdlc->xmit(skb, dev); /* Ignore return value :-( */
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}
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static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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int result;
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/* X.25 to LAPB */
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switch (skb->data[0]) {
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case X25_IFACE_DATA: /* Data to be transmitted */
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skb_pull(skb, 1);
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if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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case X25_IFACE_CONNECT:
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if ((result = lapb_connect_request(dev))!= LAPB_OK) {
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if (result == LAPB_CONNECTED)
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/* Send connect confirm. msg to level 3 */
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x25_connected(dev, 0);
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else
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netdev_err(dev, "LAPB connect request failed, error code = %i\n",
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result);
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}
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break;
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case X25_IFACE_DISCONNECT:
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if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
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if (result == LAPB_NOTCONNECTED)
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/* Send disconnect confirm. msg to level 3 */
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x25_disconnected(dev, 0);
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else
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netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
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result);
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}
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break;
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default: /* to be defined */
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break;
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}
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dev_kfree_skb(skb);
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return NETDEV_TX_OK;
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}
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static int x25_open(struct net_device *dev)
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{
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int result;
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static const struct lapb_register_struct cb = {
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.connect_confirmation = x25_connected,
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.connect_indication = x25_connected,
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.disconnect_confirmation = x25_disconnected,
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.disconnect_indication = x25_disconnected,
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.data_indication = x25_data_indication,
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.data_transmit = x25_data_transmit,
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};
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result = lapb_register(dev, &cb);
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if (result != LAPB_OK)
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return result;
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return 0;
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}
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static void x25_close(struct net_device *dev)
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{
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lapb_unregister(dev);
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}
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static int x25_rx(struct sk_buff *skb)
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{
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struct net_device *dev = skb->dev;
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if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
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dev->stats.rx_dropped++;
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return NET_RX_DROP;
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}
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if (lapb_data_received(dev, skb) == LAPB_OK)
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return NET_RX_SUCCESS;
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dev->stats.rx_errors++;
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dev_kfree_skb_any(skb);
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return NET_RX_DROP;
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}
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static struct hdlc_proto proto = {
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.open = x25_open,
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.close = x25_close,
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.ioctl = x25_ioctl,
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.netif_rx = x25_rx,
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.xmit = x25_xmit,
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.module = THIS_MODULE,
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};
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static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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int result;
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switch (ifr->ifr_settings.type) {
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case IF_GET_PROTO:
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if (dev_to_hdlc(dev)->proto != &proto)
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return -EINVAL;
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ifr->ifr_settings.type = IF_PROTO_X25;
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return 0; /* return protocol only, no settable parameters */
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case IF_PROTO_X25:
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if (!capable(CAP_NET_ADMIN))
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return -EPERM;
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if (dev->flags & IFF_UP)
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return -EBUSY;
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result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
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if (result)
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return result;
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if ((result = attach_hdlc_protocol(dev, &proto, 0)))
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return result;
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dev->type = ARPHRD_X25;
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call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
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netif_dormant_off(dev);
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return 0;
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}
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return -EINVAL;
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}
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static int __init mod_init(void)
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{
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register_hdlc_protocol(&proto);
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return 0;
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}
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static void __exit mod_exit(void)
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{
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unregister_hdlc_protocol(&proto);
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}
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module_init(mod_init);
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module_exit(mod_exit);
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MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
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MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
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MODULE_LICENSE("GPL v2");
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