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1275 |
phoenix |
/*
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* AX.25 release 037
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*
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* This code REQUIRES 2.1.15 or higher/ NET3.038
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*
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* This module:
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* This module is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Most of this code is based on the SDL diagrams published in the 7th
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* ARRL Computer Networking Conference papers. The diagrams have mistakes
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* in them, but are mostly correct. Before you modify the code could you
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* read the SDL diagrams as the code is not obvious and probably very
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* easy to break;
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*
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* History
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* AX.25 036 Jonathan(G4KLX) Cloned from ax25_in.c
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* Joerg(DL1BKE) Fixed it.
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* AX.25 037 Jonathan(G4KLX) New timer architecture.
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* Joerg(DL1BKE) ax25->n2count never got reset
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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| 27 |
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <net/ax25.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/ip.h> /* For ip_rcv */
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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| 46 |
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/*
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* State machine for state 1, Awaiting Connection State.
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* The handling of the timer(s) is in file ax25_ds_timer.c.
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* Handling of state 0 and connection release is in ax25.c.
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*/
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static int ax25_ds_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
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{
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switch (frametype) {
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case AX25_SABM:
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ax25->modulus = AX25_MODULUS;
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ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
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ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
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break;
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case AX25_SABME:
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ax25->modulus = AX25_EMODULUS;
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ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
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ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
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break;
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case AX25_DISC:
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ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE);
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break;
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case AX25_UA:
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ax25_calculate_rtt(ax25);
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ax25_stop_t1timer(ax25);
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ax25_start_t3timer(ax25);
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ax25_start_idletimer(ax25);
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ax25->vs = 0;
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ax25->va = 0;
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ax25->vr = 0;
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ax25->state = AX25_STATE_3;
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ax25->n2count = 0;
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if (ax25->sk != NULL) {
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ax25->sk->state = TCP_ESTABLISHED;
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/* For WAIT_SABM connections we will produce an accept ready socket here */
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if (!ax25->sk->dead)
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ax25->sk->state_change(ax25->sk);
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}
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ax25_dama_on(ax25);
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/* according to DK4EG´s spec we are required to
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* send a RR RESPONSE FINAL NR=0.
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*/
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ax25_std_enquiry_response(ax25);
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break;
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case AX25_DM:
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if (pf) ax25_disconnect(ax25, ECONNREFUSED);
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break;
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default:
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if (pf) ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
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break;
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}
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return 0;
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}
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/*
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* State machine for state 2, Awaiting Release State.
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* The handling of the timer(s) is in file ax25_ds_timer.c
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* Handling of state 0 and connection release is in ax25.c.
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| 112 |
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*/
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static int ax25_ds_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
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{
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switch (frametype) {
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case AX25_SABM:
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case AX25_SABME:
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ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
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ax25_dama_off(ax25);
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break;
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| 122 |
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case AX25_DISC:
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ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
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ax25_dama_off(ax25);
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ax25_disconnect(ax25, 0);
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break;
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case AX25_DM:
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case AX25_UA:
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if (pf) {
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ax25_dama_off(ax25);
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ax25_disconnect(ax25, 0);
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}
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break;
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case AX25_I:
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case AX25_REJ:
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case AX25_RNR:
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case AX25_RR:
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if (pf) {
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ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
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ax25_dama_off(ax25);
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}
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break;
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default:
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break;
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}
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| 150 |
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return 0;
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}
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| 153 |
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/*
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* State machine for state 3, Connected State.
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* The handling of the timer(s) is in file ax25_timer.c
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* Handling of state 0 and connection release is in ax25.c.
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*/
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static int ax25_ds_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
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{
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int queued = 0;
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switch (frametype) {
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case AX25_SABM:
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case AX25_SABME:
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if (frametype == AX25_SABM) {
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ax25->modulus = AX25_MODULUS;
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ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
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} else {
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ax25->modulus = AX25_EMODULUS;
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ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
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}
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ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
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ax25_stop_t1timer(ax25);
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ax25_start_t3timer(ax25);
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ax25_start_idletimer(ax25);
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ax25->condition = 0x00;
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ax25->vs = 0;
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ax25->va = 0;
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ax25->vr = 0;
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ax25_requeue_frames(ax25);
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ax25_dama_on(ax25);
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break;
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| 184 |
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case AX25_DISC:
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ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
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ax25_dama_off(ax25);
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ax25_disconnect(ax25, 0);
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break;
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| 189 |
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| 190 |
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case AX25_DM:
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ax25_dama_off(ax25);
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ax25_disconnect(ax25, ECONNRESET);
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break;
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| 194 |
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| 195 |
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case AX25_RR:
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case AX25_RNR:
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| 197 |
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if (frametype == AX25_RR)
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ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
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| 199 |
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else
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| 200 |
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ax25->condition |= AX25_COND_PEER_RX_BUSY;
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| 201 |
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| 202 |
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if (ax25_validate_nr(ax25, nr)) {
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| 203 |
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if (ax25_check_iframes_acked(ax25, nr))
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| 204 |
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ax25->n2count=0;
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| 205 |
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if (type == AX25_COMMAND && pf)
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| 206 |
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ax25_ds_enquiry_response(ax25);
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| 207 |
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} else {
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| 208 |
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ax25_ds_nr_error_recovery(ax25);
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| 209 |
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ax25->state = AX25_STATE_1;
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| 210 |
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}
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| 211 |
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break;
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| 212 |
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| 213 |
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case AX25_REJ:
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ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
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| 215 |
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| 216 |
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if (ax25_validate_nr(ax25, nr)) {
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| 217 |
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if (ax25->va != nr)
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| 218 |
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ax25->n2count=0;
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| 219 |
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| 220 |
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ax25_frames_acked(ax25, nr);
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| 221 |
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ax25_calculate_rtt(ax25);
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| 222 |
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ax25_stop_t1timer(ax25);
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| 223 |
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ax25_start_t3timer(ax25);
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| 224 |
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ax25_requeue_frames(ax25);
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| 225 |
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| 226 |
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if (type == AX25_COMMAND && pf)
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| 227 |
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ax25_ds_enquiry_response(ax25);
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| 228 |
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} else {
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| 229 |
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ax25_ds_nr_error_recovery(ax25);
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| 230 |
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ax25->state = AX25_STATE_1;
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| 231 |
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}
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| 232 |
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break;
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| 233 |
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| 234 |
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case AX25_I:
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| 235 |
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if (!ax25_validate_nr(ax25, nr)) {
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| 236 |
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ax25_ds_nr_error_recovery(ax25);
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| 237 |
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ax25->state = AX25_STATE_1;
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| 238 |
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break;
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| 239 |
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}
|
| 240 |
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if (ax25->condition & AX25_COND_PEER_RX_BUSY) {
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| 241 |
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ax25_frames_acked(ax25, nr);
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| 242 |
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ax25->n2count = 0;
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| 243 |
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} else {
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| 244 |
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if (ax25_check_iframes_acked(ax25, nr))
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| 245 |
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ax25->n2count = 0;
|
| 246 |
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}
|
| 247 |
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if (ax25->condition & AX25_COND_OWN_RX_BUSY) {
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| 248 |
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if (pf) ax25_ds_enquiry_response(ax25);
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| 249 |
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break;
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| 250 |
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}
|
| 251 |
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if (ns == ax25->vr) {
|
| 252 |
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ax25->vr = (ax25->vr + 1) % ax25->modulus;
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| 253 |
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queued = ax25_rx_iframe(ax25, skb);
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| 254 |
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if (ax25->condition & AX25_COND_OWN_RX_BUSY)
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| 255 |
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ax25->vr = ns; /* ax25->vr - 1 */
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| 256 |
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ax25->condition &= ~AX25_COND_REJECT;
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| 257 |
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if (pf) {
|
| 258 |
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ax25_ds_enquiry_response(ax25);
|
| 259 |
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} else {
|
| 260 |
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if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
|
| 261 |
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ax25->condition |= AX25_COND_ACK_PENDING;
|
| 262 |
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ax25_start_t2timer(ax25);
|
| 263 |
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}
|
| 264 |
|
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}
|
| 265 |
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} else {
|
| 266 |
|
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if (ax25->condition & AX25_COND_REJECT) {
|
| 267 |
|
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if (pf) ax25_ds_enquiry_response(ax25);
|
| 268 |
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} else {
|
| 269 |
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ax25->condition |= AX25_COND_REJECT;
|
| 270 |
|
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ax25_ds_enquiry_response(ax25);
|
| 271 |
|
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ax25->condition &= ~AX25_COND_ACK_PENDING;
|
| 272 |
|
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}
|
| 273 |
|
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}
|
| 274 |
|
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break;
|
| 275 |
|
|
|
| 276 |
|
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case AX25_FRMR:
|
| 277 |
|
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case AX25_ILLEGAL:
|
| 278 |
|
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ax25_ds_establish_data_link(ax25);
|
| 279 |
|
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ax25->state = AX25_STATE_1;
|
| 280 |
|
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break;
|
| 281 |
|
|
|
| 282 |
|
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default:
|
| 283 |
|
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break;
|
| 284 |
|
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}
|
| 285 |
|
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|
| 286 |
|
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return queued;
|
| 287 |
|
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}
|
| 288 |
|
|
|
| 289 |
|
|
/*
|
| 290 |
|
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* Higher level upcall for a LAPB frame
|
| 291 |
|
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*/
|
| 292 |
|
|
int ax25_ds_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type)
|
| 293 |
|
|
{
|
| 294 |
|
|
int queued = 0, frametype, ns, nr, pf;
|
| 295 |
|
|
|
| 296 |
|
|
frametype = ax25_decode(ax25, skb, &ns, &nr, &pf);
|
| 297 |
|
|
|
| 298 |
|
|
switch (ax25->state) {
|
| 299 |
|
|
case AX25_STATE_1:
|
| 300 |
|
|
queued = ax25_ds_state1_machine(ax25, skb, frametype, pf, type);
|
| 301 |
|
|
break;
|
| 302 |
|
|
case AX25_STATE_2:
|
| 303 |
|
|
queued = ax25_ds_state2_machine(ax25, skb, frametype, pf, type);
|
| 304 |
|
|
break;
|
| 305 |
|
|
case AX25_STATE_3:
|
| 306 |
|
|
queued = ax25_ds_state3_machine(ax25, skb, frametype, ns, nr, pf, type);
|
| 307 |
|
|
break;
|
| 308 |
|
|
}
|
| 309 |
|
|
|
| 310 |
|
|
return queued;
|
| 311 |
|
|
}
|
| 312 |
|
|
|
