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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 18 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
350 lines
8.9 KiB
C
350 lines
8.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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* 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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#define pr_fmt(fmt) "X25: " fmt
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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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* x25_parse_facilities - Parse facilities from skb into the facilities structs
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*
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* @skb: sk_buff to parse
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* @facilities: Regular facilities, updated as facilities are found
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* @dte_facs: ITU DTE facilities, updated as DTE facilities are found
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* @vc_fac_mask: mask is updated with all facilities found
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*
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* Return codes:
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* -1 - Parsing error, caller should drop call and clean up
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* 0 - Parse OK, this skb has no facilities
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* >0 - Parse OK, returns the length of the facilities header
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*
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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;
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unsigned int len;
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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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if (!pskb_may_pull(skb, 1))
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return 0;
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len = skb->data[0];
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if (!pskb_may_pull(skb, 1 + len))
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return -1;
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p = skb->data + 1;
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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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if (len < 2)
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return -1;
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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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/*fall through */
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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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pr_debug("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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if (len < 3)
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return -1;
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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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pr_debug("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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if (len < 4)
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return -1;
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pr_debug("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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if (len < p[1] + 2)
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return -1;
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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 || p[1] <= 1)
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return -1;
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if (p[2] > X25_MAX_AE_LEN)
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return -1;
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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 || p[1] <= 1)
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return -1;
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if (p[2] > X25_MAX_AE_LEN)
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return -1;
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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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pr_debug("unknown facility %02X,"
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"length %d\n", p[0], p[1]);
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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 int bytecount = (dte_facs->calling_len + 1) >> 1;
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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 int 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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memset(dte, 0, sizeof(*dte));
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len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
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if (len < 0)
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return len;
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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\n");
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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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int theirs_in = theirs.throughput & 0x0f;
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int theirs_out = theirs.throughput & 0xf0;
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int ours_in = ours->throughput & 0x0f;
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int ours_out = ours->throughput & 0xf0;
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if (!ours_in || theirs_in < ours_in) {
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SOCK_DEBUG(sk, "X.25: inbound throughput negotiated\n");
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new->throughput = (new->throughput & 0xf0) | theirs_in;
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}
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if (!ours_out || theirs_out < ours_out) {
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SOCK_DEBUG(sk,
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"X.25: outbound throughput negotiated\n");
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new->throughput = (new->throughput & 0x0f) | theirs_out;
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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\n");
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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\n");
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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\n");
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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\n");
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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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pr_debug("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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pr_debug("outgoing winsize limited to 7\n");
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}
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}
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}
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