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![Shaun Pereira](/assets/img/avatar_default.png)
Allows use of the optional user facility to insert ITU-T (http://www.itu.int/ITU-T/) specified DTE facilities in call set-up x25 packets. This feature is optional; no facilities will be added if the ioctl is not used, and call setup packet remains the same as before. If the ioctls provided by the patch are used, then a facility marker will be added to the x25 packet header so that the called dte address extension facility can be differentiated from other types of facilities (as described in the ITU-T X.25 recommendation) that are also allowed in the x25 packet header. Facility markers are made up of two octets, and may be present in the x25 packet headers of call-request, incoming call, call accepted, clear request, and clear indication packets. The first of the two octets represents the facility code field and is set to zero by this patch. The second octet of the marker represents the facility parameter field and is set to 0x0F because the marker will be inserted before ITU-T type DTE facilities. Since according to ITU-T X.25 Recommendation X.25(10/96)- 7.1 "All networks will support the facility markers with a facility parameter field set to all ones or to 00001111", therefore this patch should work with all x.25 networks. While there are many ITU-T DTE facilities, this patch implements only the called and calling address extension, with placeholders in the x25_dte_facilities structure for the rest of the facilities. Testing: This patch was tested using a cisco xot router connected on its serial ports to an X.25 network, and on its lan ports to a host running an xotd daemon. It is also possible to test this patch using an xotd daemon and an x25tap patch, where the xotd daemons work back-to-back without actually using an x.25 network. See www.fyonne.net for details on how to do this. Signed-off-by: Shaun Pereira <spereira@tusc.com.au> Acked-by: Andrew Hendry <ahendry@tusc.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
313 lines
8.1 KiB
C
313 lines
8.1 KiB
C
/*
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* X.25 Packet Layer release 002
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*
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* This is ALPHA test software. This code may break your machine,
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* randomly fail to work with new releases, misbehave and/or generally
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* screw up. It might even work.
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*
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* This code REQUIRES 2.1.15 or higher
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*
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* This module:
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* This module is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* History
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* X.25 001 Split from x25_subr.c
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* mar/20/00 Daniela Squassoni Disabling/enabling of facilities
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* negotiation.
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* apr/14/05 Shaun Pereira - Allow fast select with no restriction
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* on response.
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*/
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/x25.h>
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/*
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* Parse a set of facilities into the facilities structures. Unrecognised
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* facilities are written to the debug log file.
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*/
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int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
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struct x25_dte_facilities *dte_facs, unsigned long *vc_fac_mask)
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{
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unsigned char *p = skb->data;
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unsigned int len = *p++;
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*vc_fac_mask = 0;
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/*
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* The kernel knows which facilities were set on an incoming call but
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* currently this information is not available to userspace. Here we
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* give userspace who read incoming call facilities 0 length to indicate
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* it wasn't set.
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*/
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dte_facs->calling_len = 0;
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dte_facs->called_len = 0;
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memset(dte_facs->called_ae, '\0', sizeof(dte_facs->called_ae));
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memset(dte_facs->calling_ae, '\0', sizeof(dte_facs->calling_ae));
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while (len > 0) {
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switch (*p & X25_FAC_CLASS_MASK) {
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case X25_FAC_CLASS_A:
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switch (*p) {
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case X25_FAC_REVERSE:
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if((p[1] & 0x81) == 0x81) {
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facilities->reverse = p[1] & 0x81;
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*vc_fac_mask |= X25_MASK_REVERSE;
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break;
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}
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if((p[1] & 0x01) == 0x01) {
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facilities->reverse = p[1] & 0x01;
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*vc_fac_mask |= X25_MASK_REVERSE;
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break;
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}
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if((p[1] & 0x80) == 0x80) {
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facilities->reverse = p[1] & 0x80;
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*vc_fac_mask |= X25_MASK_REVERSE;
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break;
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}
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if(p[1] == 0x00) {
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facilities->reverse
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= X25_DEFAULT_REVERSE;
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*vc_fac_mask |= X25_MASK_REVERSE;
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break;
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}
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case X25_FAC_THROUGHPUT:
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facilities->throughput = p[1];
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*vc_fac_mask |= X25_MASK_THROUGHPUT;
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break;
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case X25_MARKER:
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break;
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default:
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printk(KERN_DEBUG "X.25: unknown facility "
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"%02X, value %02X\n",
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p[0], p[1]);
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break;
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}
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p += 2;
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len -= 2;
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break;
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case X25_FAC_CLASS_B:
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switch (*p) {
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case X25_FAC_PACKET_SIZE:
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facilities->pacsize_in = p[1];
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facilities->pacsize_out = p[2];
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*vc_fac_mask |= X25_MASK_PACKET_SIZE;
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break;
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case X25_FAC_WINDOW_SIZE:
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facilities->winsize_in = p[1];
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facilities->winsize_out = p[2];
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*vc_fac_mask |= X25_MASK_WINDOW_SIZE;
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break;
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default:
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printk(KERN_DEBUG "X.25: unknown facility "
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"%02X, values %02X, %02X\n",
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p[0], p[1], p[2]);
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break;
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}
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p += 3;
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len -= 3;
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break;
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case X25_FAC_CLASS_C:
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printk(KERN_DEBUG "X.25: unknown facility %02X, "
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"values %02X, %02X, %02X\n",
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p[0], p[1], p[2], p[3]);
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p += 4;
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len -= 4;
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break;
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case X25_FAC_CLASS_D:
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switch (*p) {
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case X25_FAC_CALLING_AE:
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if (p[1] > X25_MAX_DTE_FACIL_LEN)
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break;
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dte_facs->calling_len = p[2];
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memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
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*vc_fac_mask |= X25_MASK_CALLING_AE;
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break;
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case X25_FAC_CALLED_AE:
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if (p[1] > X25_MAX_DTE_FACIL_LEN)
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break;
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dte_facs->called_len = p[2];
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memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
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*vc_fac_mask |= X25_MASK_CALLED_AE;
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break;
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default:
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printk(KERN_DEBUG "X.25: unknown facility %02X,"
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"length %d, values %02X, %02X, "
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"%02X, %02X\n",
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p[0], p[1], p[2], p[3], p[4], p[5]);
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break;
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}
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len -= p[1] + 2;
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p += p[1] + 2;
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break;
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}
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}
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return p - skb->data;
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}
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/*
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* Create a set of facilities.
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*/
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int x25_create_facilities(unsigned char *buffer,
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struct x25_facilities *facilities,
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struct x25_dte_facilities *dte_facs, unsigned long facil_mask)
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{
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unsigned char *p = buffer + 1;
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int len;
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if (!facil_mask) {
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/*
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* Length of the facilities field in call_req or
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* call_accept packets
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*/
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buffer[0] = 0;
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len = 1; /* 1 byte for the length field */
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return len;
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}
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if (facilities->reverse && (facil_mask & X25_MASK_REVERSE)) {
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*p++ = X25_FAC_REVERSE;
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*p++ = facilities->reverse;
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}
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if (facilities->throughput && (facil_mask & X25_MASK_THROUGHPUT)) {
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*p++ = X25_FAC_THROUGHPUT;
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*p++ = facilities->throughput;
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}
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if ((facilities->pacsize_in || facilities->pacsize_out) &&
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(facil_mask & X25_MASK_PACKET_SIZE)) {
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*p++ = X25_FAC_PACKET_SIZE;
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*p++ = facilities->pacsize_in ? : facilities->pacsize_out;
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*p++ = facilities->pacsize_out ? : facilities->pacsize_in;
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}
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if ((facilities->winsize_in || facilities->winsize_out) &&
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(facil_mask & X25_MASK_WINDOW_SIZE)) {
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*p++ = X25_FAC_WINDOW_SIZE;
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*p++ = facilities->winsize_in ? : facilities->winsize_out;
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*p++ = facilities->winsize_out ? : facilities->winsize_in;
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}
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if (facil_mask & (X25_MASK_CALLING_AE|X25_MASK_CALLED_AE)) {
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*p++ = X25_MARKER;
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*p++ = X25_DTE_SERVICES;
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}
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if (dte_facs->calling_len && (facil_mask & X25_MASK_CALLING_AE)) {
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unsigned bytecount = (dte_facs->calling_len % 2) ?
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dte_facs->calling_len / 2 + 1 :
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dte_facs->calling_len / 2;
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*p++ = X25_FAC_CALLING_AE;
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*p++ = 1 + bytecount;
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*p++ = dte_facs->calling_len;
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memcpy(p, dte_facs->calling_ae, bytecount);
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p += bytecount;
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}
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if (dte_facs->called_len && (facil_mask & X25_MASK_CALLED_AE)) {
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unsigned bytecount = (dte_facs->called_len % 2) ?
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dte_facs->called_len / 2 + 1 :
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dte_facs->called_len / 2;
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*p++ = X25_FAC_CALLED_AE;
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*p++ = 1 + bytecount;
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*p++ = dte_facs->called_len;
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memcpy(p, dte_facs->called_ae, bytecount);
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p+=bytecount;
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}
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len = p - buffer;
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buffer[0] = len - 1;
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return len;
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}
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/*
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* Try to reach a compromise on a set of facilities.
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*
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* The only real problem is with reverse charging.
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*/
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int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
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struct x25_facilities *new, struct x25_dte_facilities *dte)
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{
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struct x25_sock *x25 = x25_sk(sk);
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struct x25_facilities *ours = &x25->facilities;
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struct x25_facilities theirs;
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int len;
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memset(&theirs, 0, sizeof(theirs));
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memcpy(new, ours, sizeof(*new));
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len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
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/*
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* They want reverse charging, we won't accept it.
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*/
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if ((theirs.reverse & 0x01 ) && (ours->reverse & 0x01)) {
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SOCK_DEBUG(sk, "X.25: rejecting reverse charging request");
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return -1;
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}
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new->reverse = theirs.reverse;
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if (theirs.throughput) {
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if (theirs.throughput < ours->throughput) {
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SOCK_DEBUG(sk, "X.25: throughput negotiated down");
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new->throughput = theirs.throughput;
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}
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}
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if (theirs.pacsize_in && theirs.pacsize_out) {
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if (theirs.pacsize_in < ours->pacsize_in) {
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SOCK_DEBUG(sk, "X.25: packet size inwards negotiated down");
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new->pacsize_in = theirs.pacsize_in;
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}
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if (theirs.pacsize_out < ours->pacsize_out) {
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SOCK_DEBUG(sk, "X.25: packet size outwards negotiated down");
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new->pacsize_out = theirs.pacsize_out;
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}
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}
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if (theirs.winsize_in && theirs.winsize_out) {
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if (theirs.winsize_in < ours->winsize_in) {
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SOCK_DEBUG(sk, "X.25: window size inwards negotiated down");
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new->winsize_in = theirs.winsize_in;
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}
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if (theirs.winsize_out < ours->winsize_out) {
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SOCK_DEBUG(sk, "X.25: window size outwards negotiated down");
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new->winsize_out = theirs.winsize_out;
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}
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}
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return len;
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}
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/*
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* Limit values of certain facilities according to the capability of the
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* currently attached x25 link.
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*/
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void x25_limit_facilities(struct x25_facilities *facilities,
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struct x25_neigh *nb)
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{
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if (!nb->extended) {
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if (facilities->winsize_in > 7) {
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printk(KERN_DEBUG "X.25: incoming winsize limited to 7\n");
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facilities->winsize_in = 7;
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}
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if (facilities->winsize_out > 7) {
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facilities->winsize_out = 7;
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printk( KERN_DEBUG "X.25: outgoing winsize limited to 7\n");
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}
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}
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}
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