diff options
Diffstat (limited to 'kernel/net/ax25/ax25_std_in.c')
-rw-r--r-- | kernel/net/ax25/ax25_std_in.c | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/kernel/net/ax25/ax25_std_in.c b/kernel/net/ax25/ax25_std_in.c new file mode 100644 index 000000000..3fbf8f7b2 --- /dev/null +++ b/kernel/net/ax25/ax25_std_in.c @@ -0,0 +1,446 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk) + * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) + * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) + * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de) + * + * Most of this code is based on the SDL diagrams published in the 7th ARRL + * Computer Networking Conference papers. The diagrams have mistakes in them, + * but are mostly correct. Before you modify the code could you read the SDL + * diagrams as the code is not obvious and probably very easy to break. + */ +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <net/ax25.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <net/sock.h> +#include <net/tcp_states.h> +#include <asm/uaccess.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> + +/* + * State machine for state 1, Awaiting Connection State. + * The handling of the timer(s) is in file ax25_std_timer.c. + * Handling of state 0 and connection release is in ax25.c. + */ +static int ax25_std_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type) +{ + switch (frametype) { + case AX25_SABM: + ax25->modulus = AX25_MODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + break; + + case AX25_SABME: + ax25->modulus = AX25_EMODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW]; + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + break; + + case AX25_DISC: + ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE); + break; + + case AX25_UA: + if (pf) { + ax25_calculate_rtt(ax25); + ax25_stop_t1timer(ax25); + ax25_start_t3timer(ax25); + ax25_start_idletimer(ax25); + ax25->vs = 0; + ax25->va = 0; + ax25->vr = 0; + ax25->state = AX25_STATE_3; + ax25->n2count = 0; + if (ax25->sk != NULL) { + bh_lock_sock(ax25->sk); + ax25->sk->sk_state = TCP_ESTABLISHED; + /* For WAIT_SABM connections we will produce an accept ready socket here */ + if (!sock_flag(ax25->sk, SOCK_DEAD)) + ax25->sk->sk_state_change(ax25->sk); + bh_unlock_sock(ax25->sk); + } + } + break; + + case AX25_DM: + if (pf) { + if (ax25->modulus == AX25_MODULUS) { + ax25_disconnect(ax25, ECONNREFUSED); + } else { + ax25->modulus = AX25_MODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; + } + } + break; + + default: + break; + } + + return 0; +} + +/* + * State machine for state 2, Awaiting Release State. + * The handling of the timer(s) is in file ax25_std_timer.c + * Handling of state 0 and connection release is in ax25.c. + */ +static int ax25_std_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type) +{ + switch (frametype) { + case AX25_SABM: + case AX25_SABME: + ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE); + break; + + case AX25_DISC: + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + ax25_disconnect(ax25, 0); + break; + + case AX25_DM: + case AX25_UA: + if (pf) + ax25_disconnect(ax25, 0); + break; + + case AX25_I: + case AX25_REJ: + case AX25_RNR: + case AX25_RR: + if (pf) ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE); + break; + + default: + break; + } + + return 0; +} + +/* + * State machine for state 3, Connected State. + * The handling of the timer(s) is in file ax25_std_timer.c + * Handling of state 0 and connection release is in ax25.c. + */ +static int ax25_std_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type) +{ + int queued = 0; + + switch (frametype) { + case AX25_SABM: + case AX25_SABME: + if (frametype == AX25_SABM) { + ax25->modulus = AX25_MODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; + } else { + ax25->modulus = AX25_EMODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW]; + } + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + ax25_stop_t1timer(ax25); + ax25_stop_t2timer(ax25); + ax25_start_t3timer(ax25); + ax25_start_idletimer(ax25); + ax25->condition = 0x00; + ax25->vs = 0; + ax25->va = 0; + ax25->vr = 0; + ax25_requeue_frames(ax25); + break; + + case AX25_DISC: + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + ax25_disconnect(ax25, 0); + break; + + case AX25_DM: + ax25_disconnect(ax25, ECONNRESET); + break; + + case AX25_RR: + case AX25_RNR: + if (frametype == AX25_RR) + ax25->condition &= ~AX25_COND_PEER_RX_BUSY; + else + ax25->condition |= AX25_COND_PEER_RX_BUSY; + if (type == AX25_COMMAND && pf) + ax25_std_enquiry_response(ax25); + if (ax25_validate_nr(ax25, nr)) { + ax25_check_iframes_acked(ax25, nr); + } else { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + } + break; + + case AX25_REJ: + ax25->condition &= ~AX25_COND_PEER_RX_BUSY; + if (type == AX25_COMMAND && pf) + ax25_std_enquiry_response(ax25); + if (ax25_validate_nr(ax25, nr)) { + ax25_frames_acked(ax25, nr); + ax25_calculate_rtt(ax25); + ax25_stop_t1timer(ax25); + ax25_start_t3timer(ax25); + ax25_requeue_frames(ax25); + } else { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + } + break; + + case AX25_I: + if (!ax25_validate_nr(ax25, nr)) { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + break; + } + if (ax25->condition & AX25_COND_PEER_RX_BUSY) { + ax25_frames_acked(ax25, nr); + } else { + ax25_check_iframes_acked(ax25, nr); + } + if (ax25->condition & AX25_COND_OWN_RX_BUSY) { + if (pf) ax25_std_enquiry_response(ax25); + break; + } + if (ns == ax25->vr) { + ax25->vr = (ax25->vr + 1) % ax25->modulus; + queued = ax25_rx_iframe(ax25, skb); + if (ax25->condition & AX25_COND_OWN_RX_BUSY) + ax25->vr = ns; /* ax25->vr - 1 */ + ax25->condition &= ~AX25_COND_REJECT; + if (pf) { + ax25_std_enquiry_response(ax25); + } else { + if (!(ax25->condition & AX25_COND_ACK_PENDING)) { + ax25->condition |= AX25_COND_ACK_PENDING; + ax25_start_t2timer(ax25); + } + } + } else { + if (ax25->condition & AX25_COND_REJECT) { + if (pf) ax25_std_enquiry_response(ax25); + } else { + ax25->condition |= AX25_COND_REJECT; + ax25_send_control(ax25, AX25_REJ, pf, AX25_RESPONSE); + ax25->condition &= ~AX25_COND_ACK_PENDING; + } + } + break; + + case AX25_FRMR: + case AX25_ILLEGAL: + ax25_std_establish_data_link(ax25); + ax25->state = AX25_STATE_1; + break; + + default: + break; + } + + return queued; +} + +/* + * State machine for state 4, Timer Recovery State. + * The handling of the timer(s) is in file ax25_std_timer.c + * Handling of state 0 and connection release is in ax25.c. + */ +static int ax25_std_state4_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type) +{ + int queued = 0; + + switch (frametype) { + case AX25_SABM: + case AX25_SABME: + if (frametype == AX25_SABM) { + ax25->modulus = AX25_MODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; + } else { + ax25->modulus = AX25_EMODULUS; + ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW]; + } + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + ax25_stop_t1timer(ax25); + ax25_stop_t2timer(ax25); + ax25_start_t3timer(ax25); + ax25_start_idletimer(ax25); + ax25->condition = 0x00; + ax25->vs = 0; + ax25->va = 0; + ax25->vr = 0; + ax25->state = AX25_STATE_3; + ax25->n2count = 0; + ax25_requeue_frames(ax25); + break; + + case AX25_DISC: + ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE); + ax25_disconnect(ax25, 0); + break; + + case AX25_DM: + ax25_disconnect(ax25, ECONNRESET); + break; + + case AX25_RR: + case AX25_RNR: + if (frametype == AX25_RR) + ax25->condition &= ~AX25_COND_PEER_RX_BUSY; + else + ax25->condition |= AX25_COND_PEER_RX_BUSY; + if (type == AX25_RESPONSE && pf) { + ax25_stop_t1timer(ax25); + ax25->n2count = 0; + if (ax25_validate_nr(ax25, nr)) { + ax25_frames_acked(ax25, nr); + if (ax25->vs == ax25->va) { + ax25_start_t3timer(ax25); + ax25->state = AX25_STATE_3; + } else { + ax25_requeue_frames(ax25); + } + } else { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + } + break; + } + if (type == AX25_COMMAND && pf) + ax25_std_enquiry_response(ax25); + if (ax25_validate_nr(ax25, nr)) { + ax25_frames_acked(ax25, nr); + } else { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + } + break; + + case AX25_REJ: + ax25->condition &= ~AX25_COND_PEER_RX_BUSY; + if (pf && type == AX25_RESPONSE) { + ax25_stop_t1timer(ax25); + ax25->n2count = 0; + if (ax25_validate_nr(ax25, nr)) { + ax25_frames_acked(ax25, nr); + if (ax25->vs == ax25->va) { + ax25_start_t3timer(ax25); + ax25->state = AX25_STATE_3; + } else { + ax25_requeue_frames(ax25); + } + } else { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + } + break; + } + if (type == AX25_COMMAND && pf) + ax25_std_enquiry_response(ax25); + if (ax25_validate_nr(ax25, nr)) { + ax25_frames_acked(ax25, nr); + ax25_requeue_frames(ax25); + } else { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + } + break; + + case AX25_I: + if (!ax25_validate_nr(ax25, nr)) { + ax25_std_nr_error_recovery(ax25); + ax25->state = AX25_STATE_1; + break; + } + ax25_frames_acked(ax25, nr); + if (ax25->condition & AX25_COND_OWN_RX_BUSY) { + if (pf) + ax25_std_enquiry_response(ax25); + break; + } + if (ns == ax25->vr) { + ax25->vr = (ax25->vr + 1) % ax25->modulus; + queued = ax25_rx_iframe(ax25, skb); + if (ax25->condition & AX25_COND_OWN_RX_BUSY) + ax25->vr = ns; /* ax25->vr - 1 */ + ax25->condition &= ~AX25_COND_REJECT; + if (pf) { + ax25_std_enquiry_response(ax25); + } else { + if (!(ax25->condition & AX25_COND_ACK_PENDING)) { + ax25->condition |= AX25_COND_ACK_PENDING; + ax25_start_t2timer(ax25); + } + } + } else { + if (ax25->condition & AX25_COND_REJECT) { + if (pf) ax25_std_enquiry_response(ax25); + } else { + ax25->condition |= AX25_COND_REJECT; + ax25_send_control(ax25, AX25_REJ, pf, AX25_RESPONSE); + ax25->condition &= ~AX25_COND_ACK_PENDING; + } + } + break; + + case AX25_FRMR: + case AX25_ILLEGAL: + ax25_std_establish_data_link(ax25); + ax25->state = AX25_STATE_1; + break; + + default: + break; + } + + return queued; +} + +/* + * Higher level upcall for a LAPB frame + */ +int ax25_std_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type) +{ + int queued = 0, frametype, ns, nr, pf; + + frametype = ax25_decode(ax25, skb, &ns, &nr, &pf); + + switch (ax25->state) { + case AX25_STATE_1: + queued = ax25_std_state1_machine(ax25, skb, frametype, pf, type); + break; + case AX25_STATE_2: + queued = ax25_std_state2_machine(ax25, skb, frametype, pf, type); + break; + case AX25_STATE_3: + queued = ax25_std_state3_machine(ax25, skb, frametype, ns, nr, pf, type); + break; + case AX25_STATE_4: + queued = ax25_std_state4_machine(ax25, skb, frametype, ns, nr, pf, type); + break; + } + + ax25_kick(ax25); + + return queued; +} |