422 lines
9.0 KiB
C
422 lines
9.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* X.25 Packet Layer release 002
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*
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* This is ALPHA test software. This code may break your machine,
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* randomly fail to work with new releases, misbehave and/or generally
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* screw up. It might even work.
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*
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* This code REQUIRES 2.1.15 or higher
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*
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* History
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* X.25 001 Jonathan Naylor Started coding.
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* X.25 002 Jonathan Naylor New timer architecture.
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* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
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* negotiation.
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* 2000-09-04 Henner Eisen dev_hold() / dev_put() for x25_neigh.
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*/
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#define pr_fmt(fmt) "X25: " fmt
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#include <linux/kernel.h>
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#include <linux/jiffies.h>
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#include <linux/timer.h>
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#include <linux/slab.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/uaccess.h>
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#include <linux/init.h>
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#include <net/x25.h>
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LIST_HEAD(x25_neigh_list);
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DEFINE_RWLOCK(x25_neigh_list_lock);
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static void x25_t20timer_expiry(struct timer_list *);
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static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
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static void x25_transmit_restart_request(struct x25_neigh *nb);
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/*
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* Linux set/reset timer routines
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*/
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static inline void x25_start_t20timer(struct x25_neigh *nb)
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{
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mod_timer(&nb->t20timer, jiffies + nb->t20);
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}
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static void x25_t20timer_expiry(struct timer_list *t)
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{
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struct x25_neigh *nb = from_timer(nb, t, t20timer);
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x25_transmit_restart_request(nb);
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x25_start_t20timer(nb);
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}
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static inline void x25_stop_t20timer(struct x25_neigh *nb)
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{
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del_timer(&nb->t20timer);
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}
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/*
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* This handles all restart and diagnostic frames.
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*/
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void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
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unsigned short frametype)
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{
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struct sk_buff *skbn;
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switch (frametype) {
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case X25_RESTART_REQUEST:
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switch (nb->state) {
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case X25_LINK_STATE_0:
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/* This can happen when the x25 module just gets loaded
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* and doesn't know layer 2 has already connected
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*/
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nb->state = X25_LINK_STATE_3;
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x25_transmit_restart_confirmation(nb);
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break;
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case X25_LINK_STATE_2:
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x25_stop_t20timer(nb);
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nb->state = X25_LINK_STATE_3;
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break;
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case X25_LINK_STATE_3:
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/* clear existing virtual calls */
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x25_kill_by_neigh(nb);
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x25_transmit_restart_confirmation(nb);
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break;
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}
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break;
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case X25_RESTART_CONFIRMATION:
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switch (nb->state) {
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case X25_LINK_STATE_2:
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x25_stop_t20timer(nb);
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nb->state = X25_LINK_STATE_3;
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break;
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case X25_LINK_STATE_3:
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/* clear existing virtual calls */
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x25_kill_by_neigh(nb);
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x25_transmit_restart_request(nb);
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nb->state = X25_LINK_STATE_2;
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x25_start_t20timer(nb);
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break;
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}
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break;
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case X25_DIAGNOSTIC:
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if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
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break;
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pr_warn("diagnostic #%d - %02X %02X %02X\n",
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skb->data[3], skb->data[4],
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skb->data[5], skb->data[6]);
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break;
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default:
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pr_warn("received unknown %02X with LCI 000\n",
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frametype);
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break;
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}
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if (nb->state == X25_LINK_STATE_3)
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while ((skbn = skb_dequeue(&nb->queue)) != NULL)
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x25_send_frame(skbn, nb);
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}
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/*
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* This routine is called when a Restart Request is needed
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*/
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static void x25_transmit_restart_request(struct x25_neigh *nb)
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{
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unsigned char *dptr;
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int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
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struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
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if (!skb)
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return;
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skb_reserve(skb, X25_MAX_L2_LEN);
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dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
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*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
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*dptr++ = 0x00;
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*dptr++ = X25_RESTART_REQUEST;
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*dptr++ = 0x00;
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*dptr++ = 0;
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skb->sk = NULL;
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x25_send_frame(skb, nb);
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}
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/*
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* This routine is called when a Restart Confirmation is needed
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*/
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static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
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{
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unsigned char *dptr;
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int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
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struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
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if (!skb)
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return;
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skb_reserve(skb, X25_MAX_L2_LEN);
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dptr = skb_put(skb, X25_STD_MIN_LEN);
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*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
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*dptr++ = 0x00;
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*dptr++ = X25_RESTART_CONFIRMATION;
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skb->sk = NULL;
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x25_send_frame(skb, nb);
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}
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/*
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* This routine is called when a Clear Request is needed outside of the context
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* of a connected socket.
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*/
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void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
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unsigned char cause)
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{
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unsigned char *dptr;
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int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
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struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
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if (!skb)
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return;
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skb_reserve(skb, X25_MAX_L2_LEN);
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dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
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*dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
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X25_GFI_EXTSEQ :
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X25_GFI_STDSEQ);
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*dptr++ = (lci >> 0) & 0xFF;
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*dptr++ = X25_CLEAR_REQUEST;
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*dptr++ = cause;
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*dptr++ = 0x00;
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skb->sk = NULL;
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x25_send_frame(skb, nb);
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}
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void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
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{
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switch (nb->state) {
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case X25_LINK_STATE_0:
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skb_queue_tail(&nb->queue, skb);
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nb->state = X25_LINK_STATE_1;
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x25_establish_link(nb);
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break;
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case X25_LINK_STATE_1:
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case X25_LINK_STATE_2:
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skb_queue_tail(&nb->queue, skb);
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break;
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case X25_LINK_STATE_3:
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x25_send_frame(skb, nb);
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break;
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}
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}
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/*
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* Called when the link layer has become established.
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*/
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void x25_link_established(struct x25_neigh *nb)
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{
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switch (nb->state) {
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case X25_LINK_STATE_0:
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case X25_LINK_STATE_1:
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x25_transmit_restart_request(nb);
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nb->state = X25_LINK_STATE_2;
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x25_start_t20timer(nb);
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break;
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}
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}
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/*
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* Called when the link layer has terminated, or an establishment
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* request has failed.
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*/
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void x25_link_terminated(struct x25_neigh *nb)
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{
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nb->state = X25_LINK_STATE_0;
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skb_queue_purge(&nb->queue);
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x25_stop_t20timer(nb);
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/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
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x25_kill_by_neigh(nb);
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}
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/*
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* Add a new device.
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*/
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void x25_link_device_up(struct net_device *dev)
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{
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struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
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if (!nb)
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return;
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skb_queue_head_init(&nb->queue);
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timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);
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dev_hold(dev);
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nb->dev = dev;
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nb->state = X25_LINK_STATE_0;
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nb->extended = 0;
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/*
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* Enables negotiation
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*/
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nb->global_facil_mask = X25_MASK_REVERSE |
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X25_MASK_THROUGHPUT |
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X25_MASK_PACKET_SIZE |
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X25_MASK_WINDOW_SIZE;
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nb->t20 = sysctl_x25_restart_request_timeout;
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refcount_set(&nb->refcnt, 1);
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write_lock_bh(&x25_neigh_list_lock);
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list_add(&nb->node, &x25_neigh_list);
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write_unlock_bh(&x25_neigh_list_lock);
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}
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/**
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* __x25_remove_neigh - remove neighbour from x25_neigh_list
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* @nb: - neigh to remove
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*
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* Remove neighbour from x25_neigh_list. If it was there.
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* Caller must hold x25_neigh_list_lock.
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*/
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static void __x25_remove_neigh(struct x25_neigh *nb)
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{
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if (nb->node.next) {
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list_del(&nb->node);
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x25_neigh_put(nb);
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}
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}
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/*
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* A device has been removed, remove its links.
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*/
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void x25_link_device_down(struct net_device *dev)
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{
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struct x25_neigh *nb;
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struct list_head *entry, *tmp;
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write_lock_bh(&x25_neigh_list_lock);
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list_for_each_safe(entry, tmp, &x25_neigh_list) {
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nb = list_entry(entry, struct x25_neigh, node);
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if (nb->dev == dev) {
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__x25_remove_neigh(nb);
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dev_put(dev);
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}
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}
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write_unlock_bh(&x25_neigh_list_lock);
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}
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/*
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* Given a device, return the neighbour address.
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*/
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struct x25_neigh *x25_get_neigh(struct net_device *dev)
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{
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struct x25_neigh *nb, *use = NULL;
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read_lock_bh(&x25_neigh_list_lock);
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list_for_each_entry(nb, &x25_neigh_list, node) {
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if (nb->dev == dev) {
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use = nb;
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break;
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}
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}
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if (use)
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x25_neigh_hold(use);
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read_unlock_bh(&x25_neigh_list_lock);
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return use;
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}
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/*
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* Handle the ioctls that control the subscription functions.
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*/
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int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
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{
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struct x25_subscrip_struct x25_subscr;
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struct x25_neigh *nb;
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struct net_device *dev;
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int rc = -EINVAL;
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if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
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goto out;
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rc = -EFAULT;
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if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
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goto out;
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rc = -EINVAL;
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if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
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goto out;
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if ((nb = x25_get_neigh(dev)) == NULL)
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goto out_dev_put;
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dev_put(dev);
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if (cmd == SIOCX25GSUBSCRIP) {
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read_lock_bh(&x25_neigh_list_lock);
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x25_subscr.extended = nb->extended;
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x25_subscr.global_facil_mask = nb->global_facil_mask;
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read_unlock_bh(&x25_neigh_list_lock);
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rc = copy_to_user(arg, &x25_subscr,
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sizeof(x25_subscr)) ? -EFAULT : 0;
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} else {
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rc = -EINVAL;
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if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
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rc = 0;
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write_lock_bh(&x25_neigh_list_lock);
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nb->extended = x25_subscr.extended;
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nb->global_facil_mask = x25_subscr.global_facil_mask;
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write_unlock_bh(&x25_neigh_list_lock);
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}
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}
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x25_neigh_put(nb);
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out:
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return rc;
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out_dev_put:
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dev_put(dev);
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goto out;
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}
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/*
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* Release all memory associated with X.25 neighbour structures.
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*/
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void __exit x25_link_free(void)
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{
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struct x25_neigh *nb;
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struct list_head *entry, *tmp;
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write_lock_bh(&x25_neigh_list_lock);
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list_for_each_safe(entry, tmp, &x25_neigh_list) {
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struct net_device *dev;
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nb = list_entry(entry, struct x25_neigh, node);
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dev = nb->dev;
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__x25_remove_neigh(nb);
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dev_put(dev);
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}
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write_unlock_bh(&x25_neigh_list_lock);
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}
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