1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * 4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) 5 */ 6 #include <linux/errno.h> 7 #include <linux/types.h> 8 #include <linux/socket.h> 9 #include <linux/in.h> 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/timer.h> 13 #include <linux/string.h> 14 #include <linux/sockios.h> 15 #include <linux/net.h> 16 #include <net/ax25.h> 17 #include <linux/inet.h> 18 #include <linux/netdevice.h> 19 #include <linux/skbuff.h> 20 #include <net/sock.h> 21 #include <linux/uaccess.h> 22 #include <linux/fcntl.h> 23 #include <linux/mm.h> 24 #include <linux/interrupt.h> 25 26 /* 27 * The default broadcast address of an interface is QST-0; the default address 28 * is LINUX-1. The null address is defined as a callsign of all spaces with 29 * an SSID of zero. 30 */ 31 32 const ax25_address ax25_bcast = 33 {{'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}}; 34 const ax25_address ax25_defaddr = 35 {{'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, 1 << 1}}; 36 const ax25_address null_ax25_address = 37 {{' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, ' ' << 1, 0 << 1}}; 38 39 EXPORT_SYMBOL_GPL(ax25_bcast); 40 EXPORT_SYMBOL_GPL(ax25_defaddr); 41 EXPORT_SYMBOL(null_ax25_address); 42 43 /* 44 * ax25 -> ascii conversion 45 */ 46 char *ax2asc(char *buf, const ax25_address *a) 47 { 48 char c, *s; 49 int n; 50 51 for (n = 0, s = buf; n < 6; n++) { 52 c = (a->ax25_call[n] >> 1) & 0x7F; 53 54 if (c != ' ') *s++ = c; 55 } 56 57 *s++ = '-'; 58 59 if ((n = ((a->ax25_call[6] >> 1) & 0x0F)) > 9) { 60 *s++ = '1'; 61 n -= 10; 62 } 63 64 *s++ = n + '0'; 65 *s++ = '\0'; 66 67 if (*buf == '\0' || *buf == '-') 68 return "*"; 69 70 return buf; 71 72 } 73 74 EXPORT_SYMBOL(ax2asc); 75 76 /* 77 * ascii -> ax25 conversion 78 */ 79 void asc2ax(ax25_address *addr, const char *callsign) 80 { 81 const char *s; 82 int n; 83 84 for (s = callsign, n = 0; n < 6; n++) { 85 if (*s != '\0' && *s != '-') 86 addr->ax25_call[n] = *s++; 87 else 88 addr->ax25_call[n] = ' '; 89 addr->ax25_call[n] <<= 1; 90 addr->ax25_call[n] &= 0xFE; 91 } 92 93 if (*s++ == '\0') { 94 addr->ax25_call[6] = 0x00; 95 return; 96 } 97 98 addr->ax25_call[6] = *s++ - '0'; 99 100 if (*s != '\0') { 101 addr->ax25_call[6] *= 10; 102 addr->ax25_call[6] += *s++ - '0'; 103 } 104 105 addr->ax25_call[6] <<= 1; 106 addr->ax25_call[6] &= 0x1E; 107 } 108 109 EXPORT_SYMBOL(asc2ax); 110 111 /* 112 * Compare two ax.25 addresses 113 */ 114 int ax25cmp(const ax25_address *a, const ax25_address *b) 115 { 116 int ct = 0; 117 118 while (ct < 6) { 119 if ((a->ax25_call[ct] & 0xFE) != (b->ax25_call[ct] & 0xFE)) /* Clean off repeater bits */ 120 return 1; 121 ct++; 122 } 123 124 if ((a->ax25_call[ct] & 0x1E) == (b->ax25_call[ct] & 0x1E)) /* SSID without control bit */ 125 return 0; 126 127 return 2; /* Partial match */ 128 } 129 130 EXPORT_SYMBOL(ax25cmp); 131 132 /* 133 * Compare two AX.25 digipeater paths. 134 */ 135 int ax25digicmp(const ax25_digi *digi1, const ax25_digi *digi2) 136 { 137 int i; 138 139 if (digi1->ndigi != digi2->ndigi) 140 return 1; 141 142 if (digi1->lastrepeat != digi2->lastrepeat) 143 return 1; 144 145 for (i = 0; i < digi1->ndigi; i++) 146 if (ax25cmp(&digi1->calls[i], &digi2->calls[i]) != 0) 147 return 1; 148 149 return 0; 150 } 151 152 /* 153 * Given an AX.25 address pull of to, from, digi list, command/response and the start of data 154 * 155 */ 156 const unsigned char *ax25_addr_parse(const unsigned char *buf, int len, 157 ax25_address *src, ax25_address *dest, ax25_digi *digi, int *flags, 158 int *dama) 159 { 160 int d = 0; 161 162 if (len < 14) return NULL; 163 164 if (flags != NULL) { 165 *flags = 0; 166 167 if (buf[6] & AX25_CBIT) 168 *flags = AX25_COMMAND; 169 if (buf[13] & AX25_CBIT) 170 *flags = AX25_RESPONSE; 171 } 172 173 if (dama != NULL) 174 *dama = ~buf[13] & AX25_DAMA_FLAG; 175 176 /* Copy to, from */ 177 if (dest != NULL) 178 memcpy(dest, buf + 0, AX25_ADDR_LEN); 179 if (src != NULL) 180 memcpy(src, buf + 7, AX25_ADDR_LEN); 181 182 buf += 2 * AX25_ADDR_LEN; 183 len -= 2 * AX25_ADDR_LEN; 184 185 digi->lastrepeat = -1; 186 digi->ndigi = 0; 187 188 while (!(buf[-1] & AX25_EBIT)) { 189 if (d >= AX25_MAX_DIGIS) 190 return NULL; 191 if (len < AX25_ADDR_LEN) 192 return NULL; 193 194 memcpy(&digi->calls[d], buf, AX25_ADDR_LEN); 195 digi->ndigi = d + 1; 196 197 if (buf[6] & AX25_HBIT) { 198 digi->repeated[d] = 1; 199 digi->lastrepeat = d; 200 } else { 201 digi->repeated[d] = 0; 202 } 203 204 buf += AX25_ADDR_LEN; 205 len -= AX25_ADDR_LEN; 206 d++; 207 } 208 209 return buf; 210 } 211 212 /* 213 * Assemble an AX.25 header from the bits 214 */ 215 int ax25_addr_build(unsigned char *buf, const ax25_address *src, 216 const ax25_address *dest, const ax25_digi *d, int flag, int modulus) 217 { 218 int len = 0; 219 int ct = 0; 220 221 memcpy(buf, dest, AX25_ADDR_LEN); 222 buf[6] &= ~(AX25_EBIT | AX25_CBIT); 223 buf[6] |= AX25_SSSID_SPARE; 224 225 if (flag == AX25_COMMAND) buf[6] |= AX25_CBIT; 226 227 buf += AX25_ADDR_LEN; 228 len += AX25_ADDR_LEN; 229 230 memcpy(buf, src, AX25_ADDR_LEN); 231 buf[6] &= ~(AX25_EBIT | AX25_CBIT); 232 buf[6] &= ~AX25_SSSID_SPARE; 233 234 if (modulus == AX25_MODULUS) 235 buf[6] |= AX25_SSSID_SPARE; 236 else 237 buf[6] |= AX25_ESSID_SPARE; 238 239 if (flag == AX25_RESPONSE) buf[6] |= AX25_CBIT; 240 241 /* 242 * Fast path the normal digiless path 243 */ 244 if (d == NULL || d->ndigi == 0) { 245 buf[6] |= AX25_EBIT; 246 return 2 * AX25_ADDR_LEN; 247 } 248 249 buf += AX25_ADDR_LEN; 250 len += AX25_ADDR_LEN; 251 252 while (ct < d->ndigi) { 253 memcpy(buf, &d->calls[ct], AX25_ADDR_LEN); 254 255 if (d->repeated[ct]) 256 buf[6] |= AX25_HBIT; 257 else 258 buf[6] &= ~AX25_HBIT; 259 260 buf[6] &= ~AX25_EBIT; 261 buf[6] |= AX25_SSSID_SPARE; 262 263 buf += AX25_ADDR_LEN; 264 len += AX25_ADDR_LEN; 265 ct++; 266 } 267 268 buf[-1] |= AX25_EBIT; 269 270 return len; 271 } 272 273 int ax25_addr_size(const ax25_digi *dp) 274 { 275 if (dp == NULL) 276 return 2 * AX25_ADDR_LEN; 277 278 return AX25_ADDR_LEN * (2 + dp->ndigi); 279 } 280 281 /* 282 * Reverse Digipeat List. May not pass both parameters as same struct 283 */ 284 void ax25_digi_invert(const ax25_digi *in, ax25_digi *out) 285 { 286 int ct; 287 288 out->ndigi = in->ndigi; 289 out->lastrepeat = in->ndigi - in->lastrepeat - 2; 290 291 /* Invert the digipeaters */ 292 for (ct = 0; ct < in->ndigi; ct++) { 293 out->calls[ct] = in->calls[in->ndigi - ct - 1]; 294 295 if (ct <= out->lastrepeat) { 296 out->calls[ct].ax25_call[6] |= AX25_HBIT; 297 out->repeated[ct] = 1; 298 } else { 299 out->calls[ct].ax25_call[6] &= ~AX25_HBIT; 300 out->repeated[ct] = 0; 301 } 302 } 303 } 304