diff options
Diffstat (limited to 'net/ax25/ax25_addr.c')
| -rw-r--r-- | net/ax25/ax25_addr.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/net/ax25/ax25_addr.c b/net/ax25/ax25_addr.c new file mode 100644 index 0000000..f4fa6df --- /dev/null +++ b/net/ax25/ax25_addr.c @@ -0,0 +1,290 @@ +/* + * This program 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. + * + * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) + */ +#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 <net/ax25.h> +#include <linux/inet.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <net/sock.h> +#include <asm/uaccess.h> +#include <asm/system.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> + +/* + * The null address is defined as a callsign of all spaces with an + * SSID of zero. + */ +ax25_address null_ax25_address = {{0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x00}}; + +/* + * ax25 -> ascii conversion + */ +char *ax2asc(ax25_address *a) +{ + static char buf[11]; + char c, *s; + int n; + + for (n = 0, s = buf; n < 6; n++) { + c = (a->ax25_call[n] >> 1) & 0x7F; + + if (c != ' ') *s++ = c; + } + + *s++ = '-'; + + if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { + *s++ = '1'; + n -= 10; + } + + *s++ = n + '0'; + *s++ = '\0'; + + if (*buf == '\0' || *buf == '-') + return "*"; + + return buf; + +} + +/* + * ascii -> ax25 conversion + */ +ax25_address *asc2ax(char *callsign) +{ + static ax25_address addr; + char *s; + int n; + + for (s = callsign, n = 0; n < 6; n++) { + if (*s != '\0' && *s != '-') + addr.ax25_call[n] = *s++; + else + addr.ax25_call[n] = ' '; + addr.ax25_call[n] <<= 1; + addr.ax25_call[n] &= 0xFE; + } + + if (*s++ == '\0') { + addr.ax25_call[6] = 0x00; + return &addr; + } + + addr.ax25_call[6] = *s++ - '0'; + + if (*s != '\0') { + addr.ax25_call[6] *= 10; + addr.ax25_call[6] += *s++ - '0'; + } + + addr.ax25_call[6] <<= 1; + addr.ax25_call[6] &= 0x1E; + + return &addr; +} + +/* + * Compare two ax.25 addresses + */ +int ax25cmp(ax25_address *a, ax25_address *b) +{ + int ct = 0; + + while (ct < 6) { + if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE)) /* Clean off repeater bits */ + return 1; + ct++; + } + + if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E)) /* SSID without control bit */ + return 0; + + return 2; /* Partial match */ +} + +/* + * Compare two AX.25 digipeater paths. + */ +int ax25digicmp(ax25_digi *digi1, ax25_digi *digi2) +{ + int i; + + if (digi1->ndigi != digi2->ndigi) + return 1; + + if (digi1->lastrepeat != digi2->lastrepeat) + return 1; + + for (i = 0; i < digi1->ndigi; i++) + if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0) + return 1; + + return 0; +} + +/* + * Given an AX.25 address pull of to, from, digi list, command/response and the start of data + * + */ +unsigned char *ax25_addr_parse(unsigned char *buf, int len, ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags, int *dama) +{ + int d = 0; + + if (len < 14) return NULL; + + if (flags != NULL) { + *flags = 0; + + if (buf[6] & AX25_CBIT) + *flags = AX25_COMMAND; + if (buf[13] & AX25_CBIT) + *flags = AX25_RESPONSE; + } + + if (dama != NULL) + *dama = ~buf[13] & AX25_DAMA_FLAG; + + /* Copy to, from */ + if (dest != NULL) + memcpy(dest, buf + 0, AX25_ADDR_LEN); + if (src != NULL) + memcpy(src, buf + 7, AX25_ADDR_LEN); + + buf += 2 * AX25_ADDR_LEN; + len -= 2 * AX25_ADDR_LEN; + + digi->lastrepeat = -1; + digi->ndigi = 0; + + while (!(buf[-1] & AX25_EBIT)) { + if (d >= AX25_MAX_DIGIS) return NULL; /* Max of 6 digis */ + if (len < 7) return NULL; /* Short packet */ + + memcpy(&digi->calls[d], buf, AX25_ADDR_LEN); + digi->ndigi = d + 1; + + if (buf[6] & AX25_HBIT) { + digi->repeated[d] = 1; + digi->lastrepeat = d; + } else { + digi->repeated[d] = 0; + } + + buf += AX25_ADDR_LEN; + len -= AX25_ADDR_LEN; + d++; + } + + return buf; +} + +/* + * Assemble an AX.25 header from the bits + */ +int ax25_addr_build(unsigned char *buf, ax25_address *src, ax25_address *dest, ax25_digi *d, int flag, int modulus) +{ + int len = 0; + int ct = 0; + + memcpy(buf, dest, AX25_ADDR_LEN); + buf[6] &= ~(AX25_EBIT | AX25_CBIT); + buf[6] |= AX25_SSSID_SPARE; + + if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT; + + buf += AX25_ADDR_LEN; + len += AX25_ADDR_LEN; + + memcpy(buf, src, AX25_ADDR_LEN); + buf[6] &= ~(AX25_EBIT | AX25_CBIT); + buf[6] &= ~AX25_SSSID_SPARE; + + if (modulus == AX25_MODULUS) + buf[6] |= AX25_SSSID_SPARE; + else + buf[6] |= AX25_ESSID_SPARE; + + if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT; + + /* + * Fast path the normal digiless path + */ + if (d == NULL || d->ndigi == 0) { + buf[6] |= AX25_EBIT; + return 2 * AX25_ADDR_LEN; + } + + buf += AX25_ADDR_LEN; + len += AX25_ADDR_LEN; + + while (ct < d->ndigi) { + memcpy(buf, &d->calls[ct], AX25_ADDR_LEN); + + if (d->repeated[ct]) + buf[6] |= AX25_HBIT; + else + buf[6] &= ~AX25_HBIT; + + buf[6] &= ~AX25_EBIT; + buf[6] |= AX25_SSSID_SPARE; + + buf += AX25_ADDR_LEN; + len += AX25_ADDR_LEN; + ct++; + } + + buf[-1] |= AX25_EBIT; + + return len; +} + +int ax25_addr_size(ax25_digi *dp) +{ + if (dp == NULL) + return 2 * AX25_ADDR_LEN; + + return AX25_ADDR_LEN * (2 + dp->ndigi); +} + +/* + * Reverse Digipeat List. May not pass both parameters as same struct + */ +void ax25_digi_invert(ax25_digi *in, ax25_digi *out) +{ + int ct; + + out->ndigi = in->ndigi; + out->lastrepeat = in->ndigi - in->lastrepeat - 2; + + /* Invert the digipeaters */ + for (ct = 0; ct < in->ndigi; ct++) { + out->calls[ct] = in->calls[in->ndigi - ct - 1]; + + if (ct <= out->lastrepeat) { + out->calls[ct].ax25_call[6] |= AX25_HBIT; + out->repeated[ct] = 1; + } else { + out->calls[ct].ax25_call[6] &= ~AX25_HBIT; + out->repeated[ct] = 0; + } + } +} + |
