patch-2.1.16 linux/net/x25/x25_subr.c

• Lines: 433
• Date: Wed Dec 18 12:07:56 1996
• Orig file: v2.1.15/linux/net/x25/x25_subr.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.15/linux/net/x25/x25_subr.c linux/net/x25/x25_subr.c
@@ -0,0 +1,432 @@
+/*
+ *	X.25 Packet Layer release 001
+ *
+ *	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
+ *
+ *	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.
+ *
+ *	History
+ *	X.25 001	Jonathan Naylor	Started coding.
+ */
+ 
+#include <linux/config.h>
+#if defined(CONFIG_X25) || defined(CONFIG_X25_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 <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <net/x25.h>
+
+/*
+ *	This routine purges all of the queues of frames.
+ */
+void x25_clear_queues(struct sock *sk)
+{
+	struct sk_buff *skb;
+
+	while ((skb = skb_dequeue(&sk->write_queue)) != NULL) {
+		skb->sk = sk;
+		kfree_skb(skb, FREE_WRITE);
+	}
+
+	while ((skb = skb_dequeue(&sk->protinfo.x25->ack_queue)) != NULL) {
+		skb->sk = sk;
+		kfree_skb(skb, FREE_WRITE);
+	}
+
+	while ((skb = skb_dequeue(&sk->protinfo.x25->interrupt_queue)) != NULL) {
+		skb->sk = sk;
+		kfree_skb(skb, FREE_WRITE);
+	}
+
+	while ((skb = skb_dequeue(&sk->protinfo.x25->fragment_queue)) != NULL) {
+		skb->sk = sk;
+		kfree_skb(skb, FREE_READ);
+	}
+}
+
+/*
+ * This routine purges the input queue of those frames that have been
+ * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
+ * SDL diagram.
+ */
+void x25_frames_acked(struct sock *sk, unsigned short nr)
+{
+	struct sk_buff *skb;
+	int modulus;
+	
+	modulus = (sk->protinfo.x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
+
+	/*
+	 * Remove all the ack-ed frames from the ack queue.
+	 */
+	if (sk->protinfo.x25->va != nr) {
+		while (skb_peek(&sk->protinfo.x25->ack_queue) != NULL && sk->protinfo.x25->va != nr) {
+		        skb     = skb_dequeue(&sk->protinfo.x25->ack_queue);
+		        skb->sk = sk;
+			kfree_skb(skb, FREE_WRITE);
+			sk->protinfo.x25->va = (sk->protinfo.x25->va + 1) % modulus;
+		}
+	}
+}
+
+/*
+ * Requeue all the un-ack-ed frames on the output queue to be picked
+ * up by x25_kick called from the timer. This arrangement handles the
+ * possibility of an empty output queue.
+ */
+void x25_requeue_frames(struct sock *sk)
+{
+	struct sk_buff *skb, *skb_prev = NULL;
+
+	while ((skb = skb_dequeue(&sk->protinfo.x25->ack_queue)) != NULL) {
+		if (skb_prev == NULL)
+			skb_queue_head(&sk->write_queue, skb);
+		else
+			skb_append(skb_prev, skb);
+		skb_prev = skb;
+	}
+}
+
+/*
+ *	Validate that the value of nr is between va and vs. Return true or
+ *	false for testing.
+ */
+int x25_validate_nr(struct sock *sk, unsigned short nr)
+{
+	unsigned short vc = sk->protinfo.x25->va;
+	int modulus;
+
+	modulus = (sk->protinfo.x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
+
+	while (vc != sk->protinfo.x25->vs) {
+		if (nr == vc) return 1;
+		vc = (vc + 1) % modulus;
+	}
+	
+	if (nr == sk->protinfo.x25->vs) return 1;
+
+	return 0;
+}
+
+/* 
+ *  This routine is called when the packet layer internally generates a
+ *  control frame.
+ */
+void x25_write_internal(struct sock *sk, int frametype)
+{
+	struct sk_buff *skb;
+	unsigned char  *dptr;
+	unsigned char  facilities[X25_MAX_FAC_LEN];
+	unsigned char  addresses[1 + X25_ADDR_LEN];
+	unsigned char  lci1, lci2;
+	int len;
+
+	/*
+	 *	Default safe frame size.
+	 */
+	len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
+
+	/*
+	 *	Adjust frame size.
+	 */	
+	switch (frametype) {
+		case X25_CALL_REQUEST:
+			len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN;
+			break;
+		case X25_CALL_ACCEPTED:
+			len += 1 + X25_MAX_FAC_LEN;
+			break;
+		case X25_CLEAR_REQUEST:
+		case X25_RESET_REQUEST:
+			len += 2;
+			break;
+		case X25_RR:
+		case X25_RNR:
+		case X25_REJ:
+		case X25_CLEAR_CONFIRMATION:
+		case X25_INTERRUPT_CONFIRMATION:
+		case X25_RESET_CONFIRMATION:
+			break;
+		default:
+			printk(KERN_ERR "X.25: invalid frame type %02X\n", frametype);
+			return;
+	}
+	
+	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
+		return;
+
+	/*
+	 *	Space for Ethernet and 802.2 LLC headers.
+	 */
+	skb_reserve(skb, X25_MAX_L2_LEN);
+	
+	/*
+	 *	Make space for the GFI and LCI, and fill them in.
+	 */
+	dptr = skb_put(skb, 2);
+
+	lci1 = (sk->protinfo.x25->lci >> 8) & 0x0F;
+	lci2 = (sk->protinfo.x25->lci >> 0) & 0xFF;
+
+	if (sk->protinfo.x25->neighbour->extended) {
+		*dptr++ = lci1 | X25_GFI_EXTSEQ;
+		*dptr++ = lci2;
+	} else {
+		*dptr++ = lci1 | X25_GFI_STDSEQ;
+		*dptr++ = lci2;
+	}
+
+	/*
+	 *	Now fill in the frame type specific information.
+	 */
+	switch (frametype) {
+	
+		case X25_CALL_REQUEST:
+			dptr    = skb_put(skb, 1);
+			*dptr++ = X25_CALL_REQUEST;
+			len     = x25_addr_aton(addresses, &sk->protinfo.x25->dest_addr, &sk->protinfo.x25->source_addr);
+			dptr    = skb_put(skb, len);
+			memcpy(dptr, addresses, len);
+			len     = x25_create_facilities(facilities, &sk->protinfo.x25->facilities);
+			dptr    = skb_put(skb, len);
+			memcpy(dptr, facilities, len);
+			break;
+
+		case X25_CALL_ACCEPTED:
+			dptr    = skb_put(skb, 2);
+			*dptr++ = X25_CALL_ACCEPTED;
+			*dptr++ = 0x00;		/* Address lengths */
+			len     = x25_create_facilities(facilities, &sk->protinfo.x25->facilities);
+			dptr    = skb_put(skb, len);
+			memcpy(dptr, facilities, len);
+			break;
+
+		case X25_CLEAR_REQUEST:
+		case X25_RESET_REQUEST:
+			dptr    = skb_put(skb, 3);
+			*dptr++ = frametype;
+			*dptr++ = 0x00;		/* XXX */
+			*dptr++ = 0x00;		/* XXX */
+			break;
+
+		case X25_RR:
+		case X25_RNR:
+		case X25_REJ:
+			if (sk->protinfo.x25->neighbour->extended) {
+				dptr     = skb_put(skb, 2);
+				*dptr++  = frametype;
+				*dptr++  = (sk->protinfo.x25->vr << 1) & 0xFE;
+			} else {
+				dptr     = skb_put(skb, 1);
+				*dptr    = frametype;
+				*dptr++ |= (sk->protinfo.x25->vr << 5) & 0xE0;
+			}
+			break;
+		
+		case X25_CLEAR_CONFIRMATION:
+		case X25_INTERRUPT_CONFIRMATION:
+		case X25_RESET_CONFIRMATION:
+			dptr  = skb_put(skb, 1);
+			*dptr = frametype;
+			break;
+	}
+
+	x25_transmit_link(skb, sk->protinfo.x25->neighbour);
+}
+
+/*
+ *	Unpick the contents of the passed X.25 Packet Layer frame.
+ */
+int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
+{
+	unsigned char *frame;
+	
+	frame = skb->data;
+	
+	*ns = *nr = *q = *d = *m = 0;
+
+	switch (frame[2]) {
+		case X25_CALL_REQUEST:
+		case X25_CALL_ACCEPTED:
+		case X25_CLEAR_REQUEST:
+		case X25_CLEAR_CONFIRMATION:
+		case X25_INTERRUPT:
+		case X25_INTERRUPT_CONFIRMATION:
+		case X25_RESET_REQUEST:
+		case X25_RESET_CONFIRMATION:
+		case X25_RESTART_REQUEST:
+		case X25_RESTART_CONFIRMATION:
+		case X25_REGISTRATION_REQUEST:
+		case X25_REGISTRATION_CONFIRMATION:
+		case X25_DIAGNOSTIC:
+			return frame[2];
+	}
+
+	if (sk->protinfo.x25->neighbour->extended) {
+		if (frame[2] == X25_RR  ||
+		    frame[2] == X25_RNR ||
+		    frame[2] == X25_REJ) {
+			*nr = (frame[3] >> 1) & 0x7F;
+			return frame[2];
+		}
+	} else {
+		if ((frame[2] & 0x1F) == X25_RR  ||
+		    (frame[2] & 0x1F) == X25_RNR ||
+		    (frame[2] & 0x1F) == X25_REJ) {
+			*nr = (frame[2] >> 5) & 0x07;
+			return frame[2] & 0x1F;
+		}
+	}
+
+	if (sk->protinfo.x25->neighbour->extended) {
+		if ((frame[2] & 0x01) == X25_DATA) {
+			*q  = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
+			*d  = (frame[0] & X25_D_BIT) == X25_D_BIT;
+			*m  = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
+			*nr = (frame[3] >> 1) & 0x7F;
+			*ns = (frame[2] >> 1) & 0x7F;
+			return X25_DATA;
+		}
+	} else {
+		if ((frame[2] & 0x01) == X25_DATA) {
+			*q  = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
+			*d  = (frame[0] & X25_D_BIT) == X25_D_BIT;
+			*m  = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
+			*nr = (frame[2] >> 5) & 0x07;
+			*ns = (frame[2] >> 1) & 0x07;
+			return X25_DATA;
+		}
+	}
+
+	printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n", frame[0], frame[1], frame[2]);
+	
+	return X25_ILLEGAL;
+}
+
+/*
+ *	Parse a set of facilities into the facilities structure. Unrecognised
+ *	facilities are written to the debug log file.
+ */
+int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities)
+{
+	unsigned int len;
+	unsigned char *p = skb->data;
+
+	facilities->window_size = -1;
+	facilities->packet_size = -1;
+	facilities->throughput  = -1;
+	facilities->reverse     = -1;
+
+	len = *p++;
+
+	while (len > 0) {
+		switch (*p & X25_FAC_CLASS_MASK) {
+			case X25_FAC_CLASS_A:
+				switch (*p) {
+					case X25_FAC_REVERSE:
+						facilities->reverse = (p[1] & 0x01);
+						break;
+					case X25_FAC_THROUGHPUT:
+						facilities->throughput = p[1];
+						break;
+					default:
+						printk(KERN_DEBUG "X.25: unknown facility %02X, value %02X\n", p[0], p[1]);
+						break;
+				}
+				p   += 2;
+				len -= 2;
+				break;
+				
+			case X25_FAC_CLASS_B:
+				switch (*p) {
+					case X25_FAC_PACKET_SIZE:
+						facilities->packet_size = p[1];
+						break;
+					case X25_FAC_WINDOW_SIZE:
+						facilities->window_size = p[1];
+						break;
+					default:
+						printk(KERN_DEBUG "X.25: unknown facility %02X, values %02X, %02X\n", p[0], p[1], p[2]);
+						break;
+				}
+				p   += 3;
+				len -= 3;
+				break;
+
+			case X25_FAC_CLASS_C:
+				printk(KERN_DEBUG "X.25: unknown facility %02X, values %02X, %02X, %02X\n", p[0], p[1], p[2], p[3]);
+				p   += 4;
+				len -= 4;
+				break;
+				
+			case X25_FAC_CLASS_D:
+				printk(KERN_DEBUG "X.25: unknown facility %02X, length %d, values %02X, %02X, %02X, %02X\n", p[0], p[1], p[2], p[3], p[4], p[5]);
+				p   += p[1] + 2;
+				len -= p[1] + 2;
+				break;
+		}
+	}
+
+	return p - skb->data;
+}
+
+/*
+ *	Create a set of facilities.
+ */
+int x25_create_facilities(unsigned char *buffer, struct x25_facilities *facilities)
+{
+	unsigned char *p = buffer + 1;
+	int len;
+
+	if (facilities->reverse != -1) {
+		*p++ = X25_FAC_REVERSE;
+		*p++ = (facilities->reverse) ? 0x01 : 0x00;
+	}
+
+	if (facilities->throughput != -1) {
+		*p++ = X25_FAC_THROUGHPUT;
+		*p++ = facilities->throughput;
+	}
+
+	if (facilities->packet_size != -1) {
+		*p++ = X25_FAC_PACKET_SIZE;
+		*p++ = facilities->packet_size;
+		*p++ = facilities->packet_size;
+	}
+
+	if (facilities->window_size != -1) {
+		*p++ = X25_FAC_WINDOW_SIZE;
+		*p++ = facilities->window_size;
+		*p++ = facilities->window_size;
+	}
+
+	len       = p - buffer;
+	buffer[0] = len - 1;
+	
+	return len;
+}
+
+#endif