307 lines
6 KiB
C
307 lines
6 KiB
C
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <net/ax25.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <linux/uaccess.h>
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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/*
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* The default broadcast address of an interface is QST-0; the default address
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* is LINUX-1. The null address is defined as a callsign of all spaces with
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* an SSID of zero.
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*/
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const ax25_address ax25_bcast =
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{{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
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const ax25_address ax25_defaddr =
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{{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, 1 << 1}};
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const ax25_address null_ax25_address =
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{{' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}};
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EXPORT_SYMBOL_GPL(ax25_bcast);
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EXPORT_SYMBOL_GPL(ax25_defaddr);
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EXPORT_SYMBOL(null_ax25_address);
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/*
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* ax25 -> ascii conversion
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*/
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char *ax2asc(char *buf, const ax25_address *a)
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{
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char c, *s;
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int n;
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for (n = 0, s = buf; n < 6; n++) {
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c = (a->ax25_call[n] >> 1) & 0x7F;
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if (c != ' ') *s++ = c;
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}
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*s++ = '-';
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if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) {
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*s++ = '1';
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n -= 10;
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}
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*s++ = n + '0';
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*s++ = '\0';
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if (*buf == '\0' || *buf == '-')
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return "*";
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return buf;
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}
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EXPORT_SYMBOL(ax2asc);
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/*
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* ascii -> ax25 conversion
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*/
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void asc2ax(ax25_address *addr, const char *callsign)
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{
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const char *s;
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int n;
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for (s = callsign, n = 0; n < 6; n++) {
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if (*s != '\0' && *s != '-')
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addr->ax25_call[n] = *s++;
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else
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addr->ax25_call[n] = ' ';
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addr->ax25_call[n] <<= 1;
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addr->ax25_call[n] &= 0xFE;
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}
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if (*s++ == '\0') {
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addr->ax25_call[6] = 0x00;
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return;
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}
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addr->ax25_call[6] = *s++ - '0';
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if (*s != '\0') {
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addr->ax25_call[6] *= 10;
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addr->ax25_call[6] += *s++ - '0';
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}
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addr->ax25_call[6] <<= 1;
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addr->ax25_call[6] &= 0x1E;
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}
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EXPORT_SYMBOL(asc2ax);
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/*
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* Compare two ax.25 addresses
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*/
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int ax25cmp(const ax25_address *a, const ax25_address *b)
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{
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int ct = 0;
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while (ct < 6) {
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if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE)) /* Clean off repeater bits */
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return 1;
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ct++;
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}
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if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E)) /* SSID without control bit */
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return 0;
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return 2; /* Partial match */
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}
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EXPORT_SYMBOL(ax25cmp);
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/*
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* Compare two AX.25 digipeater paths.
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*/
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int ax25digicmp(const ax25_digi *digi1, const ax25_digi *digi2)
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{
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int i;
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if (digi1->ndigi != digi2->ndigi)
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return 1;
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if (digi1->lastrepeat != digi2->lastrepeat)
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return 1;
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for (i = 0; i < digi1->ndigi; i++)
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if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0)
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return 1;
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return 0;
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}
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/*
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* Given an AX.25 address pull of to, from, digi list, command/response and the start of data
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*
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*/
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const unsigned char *ax25_addr_parse(const unsigned char *buf, int len,
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ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags,
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int *dama)
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{
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int d = 0;
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if (len < 14) return NULL;
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if (flags != NULL) {
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*flags = 0;
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if (buf[6] & AX25_CBIT)
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*flags = AX25_COMMAND;
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if (buf[13] & AX25_CBIT)
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*flags = AX25_RESPONSE;
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}
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if (dama != NULL)
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*dama = ~buf[13] & AX25_DAMA_FLAG;
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/* Copy to, from */
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if (dest != NULL)
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memcpy(dest, buf + 0, AX25_ADDR_LEN);
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if (src != NULL)
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memcpy(src, buf + 7, AX25_ADDR_LEN);
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buf += 2 * AX25_ADDR_LEN;
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len -= 2 * AX25_ADDR_LEN;
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digi->lastrepeat = -1;
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digi->ndigi = 0;
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while (!(buf[-1] & AX25_EBIT)) {
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if (d >= AX25_MAX_DIGIS)
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return NULL;
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if (len < AX25_ADDR_LEN)
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return NULL;
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memcpy(&digi->calls[d], buf, AX25_ADDR_LEN);
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digi->ndigi = d + 1;
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if (buf[6] & AX25_HBIT) {
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digi->repeated[d] = 1;
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digi->lastrepeat = d;
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} else {
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digi->repeated[d] = 0;
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}
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buf += AX25_ADDR_LEN;
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len -= AX25_ADDR_LEN;
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d++;
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}
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return buf;
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}
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/*
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* Assemble an AX.25 header from the bits
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*/
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int ax25_addr_build(unsigned char *buf, const ax25_address *src,
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const ax25_address *dest, const ax25_digi *d, int flag, int modulus)
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{
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int len = 0;
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int ct = 0;
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memcpy(buf, dest, AX25_ADDR_LEN);
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buf[6] &= ~(AX25_EBIT | AX25_CBIT);
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buf[6] |= AX25_SSSID_SPARE;
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if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT;
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buf += AX25_ADDR_LEN;
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len += AX25_ADDR_LEN;
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memcpy(buf, src, AX25_ADDR_LEN);
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buf[6] &= ~(AX25_EBIT | AX25_CBIT);
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buf[6] &= ~AX25_SSSID_SPARE;
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if (modulus == AX25_MODULUS)
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buf[6] |= AX25_SSSID_SPARE;
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else
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buf[6] |= AX25_ESSID_SPARE;
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if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT;
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/*
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* Fast path the normal digiless path
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*/
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if (d == NULL || d->ndigi == 0) {
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buf[6] |= AX25_EBIT;
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return 2 * AX25_ADDR_LEN;
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}
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buf += AX25_ADDR_LEN;
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len += AX25_ADDR_LEN;
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while (ct < d->ndigi) {
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memcpy(buf, &d->calls[ct], AX25_ADDR_LEN);
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if (d->repeated[ct])
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buf[6] |= AX25_HBIT;
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else
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buf[6] &= ~AX25_HBIT;
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buf[6] &= ~AX25_EBIT;
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buf[6] |= AX25_SSSID_SPARE;
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buf += AX25_ADDR_LEN;
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len += AX25_ADDR_LEN;
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ct++;
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}
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buf[-1] |= AX25_EBIT;
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return len;
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}
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int ax25_addr_size(const ax25_digi *dp)
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{
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if (dp == NULL)
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return 2 * AX25_ADDR_LEN;
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return AX25_ADDR_LEN * (2 + dp->ndigi);
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}
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/*
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* Reverse Digipeat List. May not pass both parameters as same struct
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*/
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void ax25_digi_invert(const ax25_digi *in, ax25_digi *out)
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{
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int ct;
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out->ndigi = in->ndigi;
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out->lastrepeat = in->ndigi - in->lastrepeat - 2;
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/* Invert the digipeaters */
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for (ct = 0; ct < in->ndigi; ct++) {
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out->calls[ct] = in->calls[in->ndigi - ct - 1];
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if (ct <= out->lastrepeat) {
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out->calls[ct].ax25_call[6] |= AX25_HBIT;
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out->repeated[ct] = 1;
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} else {
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out->calls[ct].ax25_call[6] &= ~AX25_HBIT;
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out->repeated[ct] = 0;
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}
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}
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}
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