patch-2.1.42 linux/net/x25/x25_facilities.c

• Lines: 204
• Date: Wed May 28 10:49:12 1997
• Orig file: v2.1.41/linux/net/x25/x25_facilities.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.41/linux/net/x25/x25_facilities.c linux/net/x25/x25_facilities.c
@@ -0,0 +1,203 @@
+/*
+ *	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	Split from x25_subr.c
+ */
+
+#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>
+
+/*
+ *	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;
+
+	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->pacsize_in  = p[1];
+						facilities->pacsize_out = p[2];
+						break;
+					case X25_FAC_WINDOW_SIZE:
+						facilities->winsize_in  = p[1];
+						facilities->winsize_out = p[2];
+						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 != 0) {
+		*p++ = X25_FAC_REVERSE;
+		*p++ = (facilities->reverse) ? 0x01 : 0x00;
+	}
+
+	if (facilities->throughput != 0) {
+		*p++ = X25_FAC_THROUGHPUT;
+		*p++ = facilities->throughput;
+	}
+
+	if (facilities->pacsize_in != 0 || facilities->pacsize_out != 0) {
+		*p++ = X25_FAC_PACKET_SIZE;
+		*p++ = (facilities->pacsize_in  == 0) ? facilities->pacsize_out : facilities->pacsize_in;
+		*p++ = (facilities->pacsize_out == 0) ? facilities->pacsize_in  : facilities->pacsize_out;
+	}
+
+	if (facilities->winsize_in != 0 || facilities->winsize_out != 0) {
+		*p++ = X25_FAC_WINDOW_SIZE;
+		*p++ = (facilities->winsize_in  == 0) ? facilities->winsize_out : facilities->winsize_in;
+		*p++ = (facilities->winsize_out == 0) ? facilities->winsize_in  : facilities->winsize_out;
+	}
+
+	len       = p - buffer;
+	buffer[0] = len - 1;
+
+	return len;
+}
+
+/*
+ *	Try to reach a compromise on a set of facilities.
+ *
+ *	The only real problem is with reverse charging.
+ */
+int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk, struct x25_facilities *new)
+{
+	struct x25_facilities *ours;
+	struct x25_facilities theirs;
+	int len;
+
+	memset(&theirs, 0x00, sizeof(struct x25_facilities));
+
+	ours = &sk->protinfo.x25->facilities;
+
+	*new = *ours;
+
+	len = x25_parse_facilities(skb, &theirs);
+
+	/*
+	 *	They want reverse charging, we won't accept it.
+	 */
+	if (theirs.reverse != 0 && ours->reverse == 0) {
+		SOCK_DEBUG(sk, "X.25: rejecting reverse charging request");
+		return -1;
+	}
+
+	new->reverse = theirs.reverse;
+
+	if (theirs.throughput != 0) {
+		if (theirs.throughput < ours->throughput) {
+			SOCK_DEBUG(sk, "X.25: throughput negotiated down");
+			new->throughput = theirs.throughput;
+		}
+	}
+
+	if (theirs.pacsize_in != 0 && theirs.pacsize_out != 0) {
+		if (theirs.pacsize_in < ours->pacsize_in) {
+			SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down");
+			new->pacsize_in = theirs.pacsize_in;
+		}
+		if (theirs.pacsize_out < ours->pacsize_out) {
+			SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down");
+			new->pacsize_out = theirs.pacsize_out;
+		}
+	}
+
+	if (theirs.winsize_in != 0 && theirs.winsize_out != 0) {
+		if (theirs.winsize_in < ours->winsize_in) {
+			SOCK_DEBUG(sk, "X.25: window size inwards negotiated down");
+			new->winsize_in = theirs.winsize_in;
+		}
+		if (theirs.winsize_out < ours->winsize_out) {
+			SOCK_DEBUG(sk, "X.25: window size outwards negotiated down");
+			new->winsize_out = theirs.winsize_out;
+		}
+	}
+
+	return len;
+}
+
+#endif