patch-2.1.27 linux/net/ax25/ax25_std_in.c

• Lines: 543
• Date: Tue Feb 25 17:12:51 1997
• Orig file: v2.1.26/linux/net/ax25/ax25_std_in.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.26/linux/net/ax25/ax25_std_in.c linux/net/ax25/ax25_std_in.c
@@ -0,0 +1,542 @@
+/*
+ *	AX.25 release 036
+ *
+ *	This is ALPHA test software. This code may break your machine, randomly fail to work with new 
+ *	releases, misbehave and/or generally screw up. It might even work. 
+ *
+ *	This code REQUIRES 2.1.15 or higher/ NET3.038
+ *
+ *	This module:
+ *		This module 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.
+ *
+ *	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;
+ *
+ *	History
+ *	AX.25 028a	Jonathan(G4KLX)	New state machine based on SDL diagrams.
+ *	AX.25 028b	Jonathan(G4KLX) Extracted AX25 control block from
+ *					the sock structure.
+ *	AX.25 029	Alan(GW4PTS)	Switched to KA9Q constant names.
+ *			Jonathan(G4KLX)	Added IP mode registration.
+ *	AX.25 030	Jonathan(G4KLX)	Added AX.25 fragment reception.
+ *					Upgraded state machine for SABME.
+ *					Added arbitrary protocol id support.
+ *	AX.25 031	Joerg(DL1BKE)	Added DAMA support
+ *			HaJo(DD8NE)	Added Idle Disc Timer T5
+ *			Joerg(DL1BKE)   Renamed it to "IDLE" with a slightly
+ *					different behaviour. Fixed defrag
+ *					routine (I hope)
+ *	AX.25 032	Darryl(G7LED)	AX.25 segmentation fixed.
+ *	AX.25 033	Jonathan(G4KLX)	Remove auto-router.
+ *					Modularisation changes.
+ *	AX.25 035	Hans(PE1AYX)	Fixed interface to IP layer.
+ *	AX.25 036	Jonathan(G4KLX)	Cloned from ax25_in.c.
+ */
+
+#include <linux/config.h>
+#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/sched.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/ip.h>			/* For ip_rcv */
+#include <asm/uaccess.h>
+#include <asm/system.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->t1timer = 0;
+				ax25->t3timer = ax25->t3;
+				ax25->idletimer = ax25->idle;
+				ax25->vs      = 0;
+				ax25->va      = 0;
+				ax25->vr      = 0;
+				ax25->state   = AX25_STATE_3;
+				ax25->n2count = 0;
+				if (ax25->sk != NULL) {
+					ax25->sk->state = TCP_ESTABLISHED;
+					/* For WAIT_SABM connections we will produce an accept ready socket here */
+					if (!ax25->sk->dead)
+						ax25->sk->state_change(ax25->sk);
+				}
+			}
+			break;
+
+		case AX25_DM:
+			if (pf) {
+				if (ax25->modulus == AX25_MODULUS) {
+					ax25_clear_queues(ax25);
+					ax25->state = AX25_STATE_0;
+					if (ax25->sk != NULL) {
+						ax25->sk->state     = TCP_CLOSE;
+						ax25->sk->err       = ECONNREFUSED;
+						ax25->sk->shutdown |= SEND_SHUTDOWN;
+						if (!ax25->sk->dead)
+							ax25->sk->state_change(ax25->sk);
+						ax25->sk->dead      = 1;
+					}
+				} 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->state = AX25_STATE_0;
+			if (ax25->sk != NULL) {
+				ax25->sk->state     = TCP_CLOSE;
+				ax25->sk->err       = 0;
+				ax25->sk->shutdown |= SEND_SHUTDOWN;
+				if (!ax25->sk->dead)
+					ax25->sk->state_change(ax25->sk);
+				ax25->sk->dead      = 1;
+			}
+			break;
+
+		case AX25_DM:
+		case AX25_UA:
+			if (pf) {
+				ax25->state = AX25_STATE_0;
+				if (ax25->sk != NULL) {
+					ax25->sk->state     = TCP_CLOSE;
+					ax25->sk->err       = 0;
+					ax25->sk->shutdown |= SEND_SHUTDOWN;
+					if (!ax25->sk->dead)
+						ax25->sk->state_change(ax25->sk);
+					ax25->sk->dead      = 1;
+				}
+			}
+			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->condition = 0x00;
+			ax25->t1timer   = 0;
+			ax25->t3timer   = ax25->t3;
+			ax25->idletimer = ax25->idle;
+			ax25->vs        = 0;
+			ax25->va        = 0;
+			ax25->vr        = 0;
+			ax25_requeue_frames(ax25);
+			break;
+
+		case AX25_DISC:
+			ax25_clear_queues(ax25);
+			ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+			ax25->t3timer = 0;
+			ax25->state   = AX25_STATE_0;
+			if (ax25->sk != NULL) {
+				ax25->sk->state     = TCP_CLOSE;
+				ax25->sk->err       = 0;
+				ax25->sk->shutdown |= SEND_SHUTDOWN;
+				if (!ax25->sk->dead)
+					ax25->sk->state_change(ax25->sk);
+				ax25->sk->dead      = 1;
+			}
+			break;
+
+		case AX25_DM:
+			ax25_clear_queues(ax25);
+			ax25->t3timer = 0;
+			ax25->state   = AX25_STATE_0;
+			if (ax25->sk != NULL) {
+				ax25->sk->state     = TCP_CLOSE;
+				ax25->sk->err       = ECONNRESET;
+				ax25->sk->shutdown |= SEND_SHUTDOWN;
+				if (!ax25->sk->dead)
+					ax25->sk->state_change(ax25->sk);
+				ax25->sk->dead      = 1;
+			}
+			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->t1timer = 0;
+				ax25->t3timer = ax25->t3;
+				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 */
+					if (pf) ax25_std_enquiry_response(ax25);
+					break;
+				}
+				ax25->condition &= ~AX25_COND_REJECT;
+				if (pf) {
+					ax25_std_enquiry_response(ax25);
+				} else {
+					if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
+						ax25->t2timer = ax25->t2;
+						ax25->condition |= AX25_COND_ACK_PENDING;
+					}
+				}
+			} 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->condition = 0x00;
+			ax25->t1timer   = 0;
+			ax25->t3timer   = ax25->t3;
+			ax25->idletimer = ax25->idle;
+			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_clear_queues(ax25);
+			ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
+			ax25->t3timer = 0;
+			ax25->state   = AX25_STATE_0;
+			if (ax25->sk != NULL) {
+				ax25->sk->state     = TCP_CLOSE;
+				ax25->sk->err       = 0;
+				ax25->sk->shutdown |= SEND_SHUTDOWN;
+				if (!ax25->sk->dead)
+					ax25->sk->state_change(ax25->sk);
+				ax25->sk->dead      = 1;
+			}
+			break;
+
+		case AX25_DM:
+			ax25_clear_queues(ax25);
+			ax25->t3timer = 0;
+			ax25->state   = AX25_STATE_0;
+			if (ax25->sk != NULL) {
+				ax25->sk->state     = TCP_CLOSE;
+				ax25->sk->err       = ECONNRESET;
+				ax25->sk->shutdown |= SEND_SHUTDOWN;
+				if (!ax25->sk->dead)
+					ax25->sk->state_change(ax25->sk);
+				ax25->sk->dead      = 1;
+			}
+			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->t1timer = 0;
+				if (ax25_validate_nr(ax25, nr)) {
+					ax25_frames_acked(ax25, nr);
+					if (ax25->vs == ax25->va) {
+						ax25->t3timer = ax25->t3;
+						ax25->n2count = 0;
+						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->t1timer = 0;
+				if (ax25_validate_nr(ax25, nr)) {
+					ax25_frames_acked(ax25, nr);
+					if (ax25->vs == ax25->va) {
+						ax25->t3timer = ax25->t3;
+						ax25->n2count = 0;
+						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 */
+					if (pf) ax25_std_enquiry_response(ax25);
+					break;
+				}
+				ax25->condition &= ~AX25_COND_REJECT;
+				if (pf) {
+					ax25_std_enquiry_response(ax25);
+				} else {
+					if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
+						ax25->t2timer = ax25->t2;
+						ax25->condition |= AX25_COND_ACK_PENDING;
+					}
+				}
+			} 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;
+	}
+
+	return queued;
+}
+
+#endif