Initial import

1 files changed, 446 insertions, 0 deletions

diff --git a/net/ax25/ax25_std_in.c b/net/ax25/ax25_std_in.c
new file mode 100644
index 000000000..3fbf8f7b2
--- /dev/null
+++ b/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;
+}