1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * 4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) 5 */ 6 #include <linux/errno.h> 7 #include <linux/types.h> 8 #include <linux/socket.h> 9 #include <linux/in.h> 10 #include <linux/kernel.h> 11 #include <linux/timer.h> 12 #include <linux/string.h> 13 #include <linux/sockios.h> 14 #include <linux/net.h> 15 #include <net/ax25.h> 16 #include <linux/inet.h> 17 #include <linux/netdevice.h> 18 #include <linux/skbuff.h> 19 #include <net/sock.h> 20 #include <linux/uaccess.h> 21 #include <linux/fcntl.h> 22 #include <linux/mm.h> 23 #include <linux/interrupt.h> 24 25 /* 26 * The following routines are taken from page 170 of the 7th ARRL Computer 27 * Networking Conference paper, as is the whole state machine. 28 */ 29 30 void ax25_std_nr_error_recovery(ax25_cb *ax25) 31 { 32 ax25_std_establish_data_link(ax25); 33 } 34 35 void ax25_std_establish_data_link(ax25_cb *ax25) 36 { 37 ax25->condition = 0x00; 38 ax25->n2count = 0; 39 40 if (ax25->modulus == AX25_MODULUS) 41 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); 42 else 43 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND); 44 45 ax25_calculate_t1(ax25); 46 ax25_stop_idletimer(ax25); 47 ax25_stop_t3timer(ax25); 48 ax25_stop_t2timer(ax25); 49 ax25_start_t1timer(ax25); 50 } 51 52 void ax25_std_transmit_enquiry(ax25_cb *ax25) 53 { 54 if (ax25->condition & AX25_COND_OWN_RX_BUSY) 55 ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_COMMAND); 56 else 57 ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_COMMAND); 58 59 ax25->condition &= ~AX25_COND_ACK_PENDING; 60 61 ax25_calculate_t1(ax25); 62 ax25_start_t1timer(ax25); 63 } 64 65 void ax25_std_enquiry_response(ax25_cb *ax25) 66 { 67 if (ax25->condition & AX25_COND_OWN_RX_BUSY) 68 ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_RESPONSE); 69 else 70 ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_RESPONSE); 71 72 ax25->condition &= ~AX25_COND_ACK_PENDING; 73 } 74 75 void ax25_std_timeout_response(ax25_cb *ax25) 76 { 77 if (ax25->condition & AX25_COND_OWN_RX_BUSY) 78 ax25_send_control(ax25, AX25_RNR, AX25_POLLOFF, AX25_RESPONSE); 79 else 80 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE); 81 82 ax25->condition &= ~AX25_COND_ACK_PENDING; 83 } 84