333 lines
9.8 KiB
C
333 lines
9.8 KiB
C
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/* $Id: isdn_x25iface.c,v 1.1.2.2 2004/01/12 22:37:19 keil Exp $
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*
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* Linux ISDN subsystem, X.25 related functions
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*
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* This software may be used and distributed according to the terms
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* of the GNU General Public License, incorporated herein by reference.
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*
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* stuff needed to support the Linux X.25 PLP code on top of devices that
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* can provide a lab_b service using the concap_proto mechanism.
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* This module supports a network interface which provides lapb_sematics
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* -- as defined in Documentation/networking/x25-iface.txt -- to
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* the upper layer and assumes that the lower layer provides a reliable
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* data link service by means of the concap_device_ops callbacks.
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*
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* Only protocol specific stuff goes here. Device specific stuff
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* goes to another -- device related -- concap_proto support source file.
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*
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*/
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/* #include <linux/isdn.h> */
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#include <linux/netdevice.h>
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#include <linux/concap.h>
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#include <linux/slab.h>
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#include <linux/wanrouter.h>
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#include <net/x25device.h>
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#include "isdn_x25iface.h"
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/* for debugging messages not to cause an oops when device pointer is NULL*/
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#define MY_DEVNAME(dev) ((dev) ? (dev)->name : "DEVICE UNSPECIFIED")
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typedef struct isdn_x25iface_proto_data {
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int magic;
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enum wan_states state;
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/* Private stuff, not to be accessed via proto_data. We provide the
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other storage for the concap_proto instance here as well,
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enabling us to allocate both with just one kmalloc(): */
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struct concap_proto priv;
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} ix25_pdata_t;
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/* is now in header file (extern): struct concap_proto * isdn_x25iface_proto_new(void); */
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static void isdn_x25iface_proto_del(struct concap_proto *);
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static int isdn_x25iface_proto_close(struct concap_proto *);
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static int isdn_x25iface_proto_restart(struct concap_proto *,
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struct net_device *,
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struct concap_device_ops *);
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static int isdn_x25iface_xmit(struct concap_proto *, struct sk_buff *);
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static int isdn_x25iface_receive(struct concap_proto *, struct sk_buff *);
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static int isdn_x25iface_connect_ind(struct concap_proto *);
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static int isdn_x25iface_disconn_ind(struct concap_proto *);
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static struct concap_proto_ops ix25_pops = {
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.proto_new = &isdn_x25iface_proto_new,
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.proto_del = &isdn_x25iface_proto_del,
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.restart = &isdn_x25iface_proto_restart,
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.close = &isdn_x25iface_proto_close,
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.encap_and_xmit = &isdn_x25iface_xmit,
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.data_ind = &isdn_x25iface_receive,
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.connect_ind = &isdn_x25iface_connect_ind,
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.disconn_ind = &isdn_x25iface_disconn_ind
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};
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/* error message helper function */
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static void illegal_state_warn(unsigned state, unsigned char firstbyte)
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{
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printk(KERN_WARNING "isdn_x25iface: firstbyte %x illegal in"
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"current state %d\n", firstbyte, state);
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}
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/* check protocol data field for consistency */
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static int pdata_is_bad(ix25_pdata_t *pda) {
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if (pda && pda->magic == ISDN_X25IFACE_MAGIC) return 0;
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printk(KERN_WARNING
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"isdn_x25iface_xxx: illegal pointer to proto data\n");
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return 1;
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}
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/* create a new x25 interface protocol instance
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*/
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struct concap_proto *isdn_x25iface_proto_new(void)
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{
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ix25_pdata_t *tmp = kmalloc(sizeof(ix25_pdata_t), GFP_KERNEL);
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IX25DEBUG("isdn_x25iface_proto_new\n");
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if (tmp) {
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tmp->magic = ISDN_X25IFACE_MAGIC;
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tmp->state = WAN_UNCONFIGURED;
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/* private data space used to hold the concap_proto data.
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Only to be accessed via the returned pointer */
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spin_lock_init(&tmp->priv.lock);
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tmp->priv.dops = NULL;
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tmp->priv.net_dev = NULL;
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tmp->priv.pops = &ix25_pops;
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tmp->priv.flags = 0;
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tmp->priv.proto_data = tmp;
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return (&(tmp->priv));
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}
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return NULL;
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};
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/* close the x25iface encapsulation protocol
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*/
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static int isdn_x25iface_proto_close(struct concap_proto *cprot) {
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ix25_pdata_t *tmp;
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int ret = 0;
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ulong flags;
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if (!cprot) {
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printk(KERN_ERR "isdn_x25iface_proto_close: "
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"invalid concap_proto pointer\n");
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return -1;
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}
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IX25DEBUG("isdn_x25iface_proto_close %s \n", MY_DEVNAME(cprot->net_dev));
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spin_lock_irqsave(&cprot->lock, flags);
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cprot->dops = NULL;
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cprot->net_dev = NULL;
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tmp = cprot->proto_data;
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if (pdata_is_bad(tmp)) {
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ret = -1;
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} else {
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tmp->state = WAN_UNCONFIGURED;
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}
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spin_unlock_irqrestore(&cprot->lock, flags);
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return ret;
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}
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/* Delete the x25iface encapsulation protocol instance
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*/
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static void isdn_x25iface_proto_del(struct concap_proto *cprot) {
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ix25_pdata_t *tmp;
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IX25DEBUG("isdn_x25iface_proto_del \n");
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if (!cprot) {
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printk(KERN_ERR "isdn_x25iface_proto_del: "
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"concap_proto pointer is NULL\n");
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return;
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}
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tmp = cprot->proto_data;
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if (tmp == NULL) {
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printk(KERN_ERR "isdn_x25iface_proto_del: inconsistent "
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"proto_data pointer (maybe already deleted?)\n");
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return;
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}
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/* close if the protocol is still open */
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if (cprot->dops) isdn_x25iface_proto_close(cprot);
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/* freeing the storage should be sufficient now. But some additional
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settings might help to catch wild pointer bugs */
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tmp->magic = 0;
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cprot->proto_data = NULL;
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kfree(tmp);
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return;
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}
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/* (re-)initialize the data structures for x25iface encapsulation
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*/
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static int isdn_x25iface_proto_restart(struct concap_proto *cprot,
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struct net_device *ndev,
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struct concap_device_ops *dops)
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{
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ix25_pdata_t *pda = cprot->proto_data;
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ulong flags;
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IX25DEBUG("isdn_x25iface_proto_restart %s \n", MY_DEVNAME(ndev));
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if (pdata_is_bad(pda)) return -1;
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if (!(dops && dops->data_req && dops->connect_req
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&& dops->disconn_req)) {
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printk(KERN_WARNING "isdn_x25iface_restart: required dops"
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" missing\n");
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isdn_x25iface_proto_close(cprot);
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return -1;
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}
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spin_lock_irqsave(&cprot->lock, flags);
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cprot->net_dev = ndev;
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cprot->pops = &ix25_pops;
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cprot->dops = dops;
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pda->state = WAN_DISCONNECTED;
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spin_unlock_irqrestore(&cprot->lock, flags);
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return 0;
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}
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/* deliver a dl_data frame received from i4l HL driver to the network layer
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*/
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static int isdn_x25iface_receive(struct concap_proto *cprot, struct sk_buff *skb)
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{
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IX25DEBUG("isdn_x25iface_receive %s \n", MY_DEVNAME(cprot->net_dev));
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if (((ix25_pdata_t *)(cprot->proto_data))
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->state == WAN_CONNECTED) {
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if (skb_push(skb, 1)) {
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skb->data[0] = X25_IFACE_DATA;
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skb->protocol = x25_type_trans(skb, cprot->net_dev);
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netif_rx(skb);
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return 0;
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}
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}
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printk(KERN_WARNING "isdn_x25iface_receive %s: not connected, skb dropped\n", MY_DEVNAME(cprot->net_dev));
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dev_kfree_skb(skb);
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return -1;
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}
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/* a connection set up is indicated by lower layer
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*/
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static int isdn_x25iface_connect_ind(struct concap_proto *cprot)
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{
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struct sk_buff *skb;
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enum wan_states *state_p
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= &(((ix25_pdata_t *)(cprot->proto_data))->state);
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IX25DEBUG("isdn_x25iface_connect_ind %s \n"
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, MY_DEVNAME(cprot->net_dev));
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if (*state_p == WAN_UNCONFIGURED) {
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printk(KERN_WARNING
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"isdn_x25iface_connect_ind while unconfigured %s\n"
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, MY_DEVNAME(cprot->net_dev));
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return -1;
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}
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*state_p = WAN_CONNECTED;
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skb = dev_alloc_skb(1);
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if (skb) {
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skb_put_u8(skb, X25_IFACE_CONNECT);
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skb->protocol = x25_type_trans(skb, cprot->net_dev);
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netif_rx(skb);
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return 0;
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} else {
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printk(KERN_WARNING "isdn_x25iface_connect_ind: "
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" out of memory -- disconnecting\n");
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cprot->dops->disconn_req(cprot);
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return -1;
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}
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}
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/* a disconnect is indicated by lower layer
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*/
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static int isdn_x25iface_disconn_ind(struct concap_proto *cprot)
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{
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struct sk_buff *skb;
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enum wan_states *state_p
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= &(((ix25_pdata_t *)(cprot->proto_data))->state);
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IX25DEBUG("isdn_x25iface_disconn_ind %s \n", MY_DEVNAME(cprot->net_dev));
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if (*state_p == WAN_UNCONFIGURED) {
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printk(KERN_WARNING
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"isdn_x25iface_disconn_ind while unconfigured\n");
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return -1;
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}
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if (!cprot->net_dev) return -1;
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*state_p = WAN_DISCONNECTED;
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skb = dev_alloc_skb(1);
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if (skb) {
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skb_put_u8(skb, X25_IFACE_DISCONNECT);
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skb->protocol = x25_type_trans(skb, cprot->net_dev);
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netif_rx(skb);
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return 0;
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} else {
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printk(KERN_WARNING "isdn_x25iface_disconn_ind:"
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" out of memory\n");
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return -1;
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}
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}
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/* process a frame handed over to us from linux network layer. First byte
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semantics as defined in Documentation/networking/x25-iface.txt
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*/
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static int isdn_x25iface_xmit(struct concap_proto *cprot, struct sk_buff *skb)
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{
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unsigned char firstbyte = skb->data[0];
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enum wan_states *state = &((ix25_pdata_t *)cprot->proto_data)->state;
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int ret = 0;
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IX25DEBUG("isdn_x25iface_xmit: %s first=%x state=%d\n",
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MY_DEVNAME(cprot->net_dev), firstbyte, *state);
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switch (firstbyte) {
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case X25_IFACE_DATA:
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if (*state == WAN_CONNECTED) {
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skb_pull(skb, 1);
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netif_trans_update(cprot->net_dev);
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ret = (cprot->dops->data_req(cprot, skb));
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/* prepare for future retransmissions */
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if (ret) skb_push(skb, 1);
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return ret;
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}
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illegal_state_warn(*state, firstbyte);
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break;
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case X25_IFACE_CONNECT:
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if (*state == WAN_DISCONNECTED) {
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*state = WAN_CONNECTING;
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ret = cprot->dops->connect_req(cprot);
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if (ret) {
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/* reset state and notify upper layer about
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* immidiatly failed attempts */
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isdn_x25iface_disconn_ind(cprot);
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}
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} else {
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illegal_state_warn(*state, firstbyte);
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}
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break;
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case X25_IFACE_DISCONNECT:
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switch (*state) {
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case WAN_DISCONNECTED:
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/* Should not happen. However, give upper layer a
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chance to recover from inconstistency but don't
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trust the lower layer sending the disconn_confirm
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when already disconnected */
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printk(KERN_WARNING "isdn_x25iface_xmit: disconnect "
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" requested while disconnected\n");
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isdn_x25iface_disconn_ind(cprot);
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break; /* prevent infinite loops */
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case WAN_CONNECTING:
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case WAN_CONNECTED:
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*state = WAN_DISCONNECTED;
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cprot->dops->disconn_req(cprot);
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break;
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default:
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illegal_state_warn(*state, firstbyte);
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}
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break;
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case X25_IFACE_PARAMS:
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printk(KERN_WARNING "isdn_x25iface_xmit: setting of lapb"
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" options not yet supported\n");
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break;
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default:
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printk(KERN_WARNING "isdn_x25iface_xmit: frame with illegal"
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" first byte %x ignored:\n", firstbyte);
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}
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dev_kfree_skb(skb);
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return 0;
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}
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