299 lines
6.9 KiB
C
299 lines
6.9 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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*
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* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
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* Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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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/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/tcp_states.h>
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#include <linux/uaccess.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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/*
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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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bh_lock_sock(ax25->sk);
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ax25->sk->sk_state = TCP_ESTABLISHED;
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/*
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* For WAIT_SABM connections we will produce an accept
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* ready socket here
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*/
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if (!sock_flag(ax25->sk, SOCK_DEAD))
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ax25->sk->sk_state_change(ax25->sk);
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bh_unlock_sock(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)
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ax25_disconnect(ax25, ECONNREFUSED);
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break;
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default:
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if (pf)
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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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*/
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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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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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return 0;
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}
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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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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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ax25_dama_off(ax25);
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ax25_disconnect(ax25, ECONNRESET);
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break;
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case AX25_RR:
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case AX25_RNR:
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if (frametype == AX25_RR)
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ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
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else
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ax25->condition |= AX25_COND_PEER_RX_BUSY;
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if (ax25_validate_nr(ax25, nr)) {
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if (ax25_check_iframes_acked(ax25, nr))
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ax25->n2count=0;
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if (type == AX25_COMMAND && pf)
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ax25_ds_enquiry_response(ax25);
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} else {
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ax25_ds_nr_error_recovery(ax25);
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ax25->state = AX25_STATE_1;
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}
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break;
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case AX25_REJ:
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ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
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if (ax25_validate_nr(ax25, nr)) {
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if (ax25->va != nr)
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ax25->n2count=0;
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ax25_frames_acked(ax25, nr);
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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_requeue_frames(ax25);
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if (type == AX25_COMMAND && pf)
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ax25_ds_enquiry_response(ax25);
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} else {
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ax25_ds_nr_error_recovery(ax25);
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ax25->state = AX25_STATE_1;
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}
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break;
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case AX25_I:
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if (!ax25_validate_nr(ax25, nr)) {
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ax25_ds_nr_error_recovery(ax25);
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ax25->state = AX25_STATE_1;
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break;
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}
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if (ax25->condition & AX25_COND_PEER_RX_BUSY) {
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ax25_frames_acked(ax25, nr);
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ax25->n2count = 0;
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} else {
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if (ax25_check_iframes_acked(ax25, nr))
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ax25->n2count = 0;
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}
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if (ax25->condition & AX25_COND_OWN_RX_BUSY) {
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if (pf) ax25_ds_enquiry_response(ax25);
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break;
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}
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if (ns == ax25->vr) {
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ax25->vr = (ax25->vr + 1) % ax25->modulus;
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queued = ax25_rx_iframe(ax25, skb);
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if (ax25->condition & AX25_COND_OWN_RX_BUSY)
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ax25->vr = ns; /* ax25->vr - 1 */
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ax25->condition &= ~AX25_COND_REJECT;
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if (pf) {
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ax25_ds_enquiry_response(ax25);
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} else {
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if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
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ax25->condition |= AX25_COND_ACK_PENDING;
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ax25_start_t2timer(ax25);
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}
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}
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} else {
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if (ax25->condition & AX25_COND_REJECT) {
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if (pf) ax25_ds_enquiry_response(ax25);
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} else {
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ax25->condition |= AX25_COND_REJECT;
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ax25_ds_enquiry_response(ax25);
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ax25->condition &= ~AX25_COND_ACK_PENDING;
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}
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}
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break;
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case AX25_FRMR:
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case AX25_ILLEGAL:
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ax25_ds_establish_data_link(ax25);
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ax25->state = AX25_STATE_1;
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break;
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default:
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break;
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}
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return queued;
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}
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/*
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* Higher level upcall for a LAPB frame
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*/
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int ax25_ds_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type)
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{
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int queued = 0, frametype, ns, nr, pf;
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frametype = ax25_decode(ax25, skb, &ns, &nr, &pf);
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switch (ax25->state) {
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case AX25_STATE_1:
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queued = ax25_ds_state1_machine(ax25, skb, frametype, pf, type);
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break;
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case AX25_STATE_2:
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queued = ax25_ds_state2_machine(ax25, skb, frametype, pf, type);
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break;
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case AX25_STATE_3:
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queued = ax25_ds_state3_machine(ax25, skb, frametype, ns, nr, pf, type);
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break;
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}
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return queued;
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}
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