1 /* 2 * X.25 Packet Layer release 002 3 * 4 * This is ALPHA test software. This code may break your machine, 5 * randomly fail to work with new releases, misbehave and/or generally 6 * screw up. It might even work. 7 * 8 * This code REQUIRES 2.1.15 or higher 9 * 10 * This module: 11 * This module is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 * 16 * History 17 * X.25 001 Jonathan Naylor Started coding. 18 * X.25 002 Jonathan Naylor Centralised disconnection processing. 19 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities 20 * negotiation. 21 * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups 22 */ 23 24 #include <linux/kernel.h> 25 #include <linux/string.h> 26 #include <linux/skbuff.h> 27 #include <net/sock.h> 28 #include <net/tcp.h> 29 #include <net/x25.h> 30 31 /* 32 * This routine purges all of the queues of frames. 33 */ 34 void x25_clear_queues(struct sock *sk) 35 { 36 struct x25_sock *x25 = x25_sk(sk); 37 38 skb_queue_purge(&sk->sk_write_queue); 39 skb_queue_purge(&x25->ack_queue); 40 skb_queue_purge(&x25->interrupt_in_queue); 41 skb_queue_purge(&x25->interrupt_out_queue); 42 skb_queue_purge(&x25->fragment_queue); 43 } 44 45 46 /* 47 * This routine purges the input queue of those frames that have been 48 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the 49 * SDL diagram. 50 */ 51 void x25_frames_acked(struct sock *sk, unsigned short nr) 52 { 53 struct sk_buff *skb; 54 struct x25_sock *x25 = x25_sk(sk); 55 int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; 56 57 /* 58 * Remove all the ack-ed frames from the ack queue. 59 */ 60 if (x25->va != nr) 61 while (skb_peek(&x25->ack_queue) && x25->va != nr) { 62 skb = skb_dequeue(&x25->ack_queue); 63 kfree_skb(skb); 64 x25->va = (x25->va + 1) % modulus; 65 } 66 } 67 68 void x25_requeue_frames(struct sock *sk) 69 { 70 struct sk_buff *skb, *skb_prev = NULL; 71 72 /* 73 * Requeue all the un-ack-ed frames on the output queue to be picked 74 * up by x25_kick. This arrangement handles the possibility of an empty 75 * output queue. 76 */ 77 while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) { 78 if (!skb_prev) 79 skb_queue_head(&sk->sk_write_queue, skb); 80 else 81 skb_append(skb_prev, skb); 82 skb_prev = skb; 83 } 84 } 85 86 /* 87 * Validate that the value of nr is between va and vs. Return true or 88 * false for testing. 89 */ 90 int x25_validate_nr(struct sock *sk, unsigned short nr) 91 { 92 struct x25_sock *x25 = x25_sk(sk); 93 unsigned short vc = x25->va; 94 int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; 95 96 while (vc != x25->vs) { 97 if (nr == vc) 98 return 1; 99 vc = (vc + 1) % modulus; 100 } 101 102 return nr == x25->vs ? 1 : 0; 103 } 104 105 /* 106 * This routine is called when the packet layer internally generates a 107 * control frame. 108 */ 109 void x25_write_internal(struct sock *sk, int frametype) 110 { 111 struct x25_sock *x25 = x25_sk(sk); 112 struct sk_buff *skb; 113 unsigned char *dptr; 114 unsigned char facilities[X25_MAX_FAC_LEN]; 115 unsigned char addresses[1 + X25_ADDR_LEN]; 116 unsigned char lci1, lci2; 117 /* 118 * Default safe frame size. 119 */ 120 int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN; 121 122 /* 123 * Adjust frame size. 124 */ 125 switch (frametype) { 126 case X25_CALL_REQUEST: 127 len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + 128 X25_MAX_CUD_LEN; 129 break; 130 case X25_CALL_ACCEPTED: 131 len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; 132 break; 133 case X25_CLEAR_REQUEST: 134 case X25_RESET_REQUEST: 135 len += 2; 136 break; 137 case X25_RR: 138 case X25_RNR: 139 case X25_REJ: 140 case X25_CLEAR_CONFIRMATION: 141 case X25_INTERRUPT_CONFIRMATION: 142 case X25_RESET_CONFIRMATION: 143 break; 144 default: 145 printk(KERN_ERR "X.25: invalid frame type %02X\n", 146 frametype); 147 return; 148 } 149 150 if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL) 151 return; 152 153 /* 154 * Space for Ethernet and 802.2 LLC headers. 155 */ 156 skb_reserve(skb, X25_MAX_L2_LEN); 157 158 /* 159 * Make space for the GFI and LCI, and fill them in. 160 */ 161 dptr = skb_put(skb, 2); 162 163 lci1 = (x25->lci >> 8) & 0x0F; 164 lci2 = (x25->lci >> 0) & 0xFF; 165 166 if (x25->neighbour->extended) { 167 *dptr++ = lci1 | X25_GFI_EXTSEQ; 168 *dptr++ = lci2; 169 } else { 170 *dptr++ = lci1 | X25_GFI_STDSEQ; 171 *dptr++ = lci2; 172 } 173 174 /* 175 * Now fill in the frame type specific information. 176 */ 177 switch (frametype) { 178 179 case X25_CALL_REQUEST: 180 dptr = skb_put(skb, 1); 181 *dptr++ = X25_CALL_REQUEST; 182 len = x25_addr_aton(addresses, &x25->dest_addr, 183 &x25->source_addr); 184 dptr = skb_put(skb, len); 185 memcpy(dptr, addresses, len); 186 len = x25_create_facilities(facilities, 187 &x25->facilities, 188 x25->neighbour->global_facil_mask); 189 dptr = skb_put(skb, len); 190 memcpy(dptr, facilities, len); 191 dptr = skb_put(skb, x25->calluserdata.cudlength); 192 memcpy(dptr, x25->calluserdata.cuddata, 193 x25->calluserdata.cudlength); 194 x25->calluserdata.cudlength = 0; 195 break; 196 197 case X25_CALL_ACCEPTED: 198 dptr = skb_put(skb, 2); 199 *dptr++ = X25_CALL_ACCEPTED; 200 *dptr++ = 0x00; /* Address lengths */ 201 len = x25_create_facilities(facilities, 202 &x25->facilities, 203 x25->vc_facil_mask); 204 dptr = skb_put(skb, len); 205 memcpy(dptr, facilities, len); 206 dptr = skb_put(skb, x25->calluserdata.cudlength); 207 memcpy(dptr, x25->calluserdata.cuddata, 208 x25->calluserdata.cudlength); 209 x25->calluserdata.cudlength = 0; 210 break; 211 212 case X25_CLEAR_REQUEST: 213 case X25_RESET_REQUEST: 214 dptr = skb_put(skb, 3); 215 *dptr++ = frametype; 216 *dptr++ = 0x00; /* XXX */ 217 *dptr++ = 0x00; /* XXX */ 218 break; 219 220 case X25_RR: 221 case X25_RNR: 222 case X25_REJ: 223 if (x25->neighbour->extended) { 224 dptr = skb_put(skb, 2); 225 *dptr++ = frametype; 226 *dptr++ = (x25->vr << 1) & 0xFE; 227 } else { 228 dptr = skb_put(skb, 1); 229 *dptr = frametype; 230 *dptr++ |= (x25->vr << 5) & 0xE0; 231 } 232 break; 233 234 case X25_CLEAR_CONFIRMATION: 235 case X25_INTERRUPT_CONFIRMATION: 236 case X25_RESET_CONFIRMATION: 237 dptr = skb_put(skb, 1); 238 *dptr = frametype; 239 break; 240 } 241 242 x25_transmit_link(skb, x25->neighbour); 243 } 244 245 /* 246 * Unpick the contents of the passed X.25 Packet Layer frame. 247 */ 248 int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q, 249 int *d, int *m) 250 { 251 struct x25_sock *x25 = x25_sk(sk); 252 unsigned char *frame = skb->data; 253 254 *ns = *nr = *q = *d = *m = 0; 255 256 switch (frame[2]) { 257 case X25_CALL_REQUEST: 258 case X25_CALL_ACCEPTED: 259 case X25_CLEAR_REQUEST: 260 case X25_CLEAR_CONFIRMATION: 261 case X25_INTERRUPT: 262 case X25_INTERRUPT_CONFIRMATION: 263 case X25_RESET_REQUEST: 264 case X25_RESET_CONFIRMATION: 265 case X25_RESTART_REQUEST: 266 case X25_RESTART_CONFIRMATION: 267 case X25_REGISTRATION_REQUEST: 268 case X25_REGISTRATION_CONFIRMATION: 269 case X25_DIAGNOSTIC: 270 return frame[2]; 271 } 272 273 if (x25->neighbour->extended) { 274 if (frame[2] == X25_RR || 275 frame[2] == X25_RNR || 276 frame[2] == X25_REJ) { 277 *nr = (frame[3] >> 1) & 0x7F; 278 return frame[2]; 279 } 280 } else { 281 if ((frame[2] & 0x1F) == X25_RR || 282 (frame[2] & 0x1F) == X25_RNR || 283 (frame[2] & 0x1F) == X25_REJ) { 284 *nr = (frame[2] >> 5) & 0x07; 285 return frame[2] & 0x1F; 286 } 287 } 288 289 if (x25->neighbour->extended) { 290 if ((frame[2] & 0x01) == X25_DATA) { 291 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; 292 *d = (frame[0] & X25_D_BIT) == X25_D_BIT; 293 *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT; 294 *nr = (frame[3] >> 1) & 0x7F; 295 *ns = (frame[2] >> 1) & 0x7F; 296 return X25_DATA; 297 } 298 } else { 299 if ((frame[2] & 0x01) == X25_DATA) { 300 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; 301 *d = (frame[0] & X25_D_BIT) == X25_D_BIT; 302 *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT; 303 *nr = (frame[2] >> 5) & 0x07; 304 *ns = (frame[2] >> 1) & 0x07; 305 return X25_DATA; 306 } 307 } 308 309 printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n", 310 frame[0], frame[1], frame[2]); 311 312 return X25_ILLEGAL; 313 } 314 315 void x25_disconnect(struct sock *sk, int reason, unsigned char cause, 316 unsigned char diagnostic) 317 { 318 struct x25_sock *x25 = x25_sk(sk); 319 320 x25_clear_queues(sk); 321 x25_stop_timer(sk); 322 323 x25->lci = 0; 324 x25->state = X25_STATE_0; 325 326 x25->causediag.cause = cause; 327 x25->causediag.diagnostic = diagnostic; 328 329 sk->sk_state = TCP_CLOSE; 330 sk->sk_err = reason; 331 sk->sk_shutdown |= SEND_SHUTDOWN; 332 333 if (!sock_flag(sk, SOCK_DEAD)) { 334 sk->sk_state_change(sk); 335 sock_set_flag(sk, SOCK_DEAD); 336 } 337 } 338 339 /* 340 * Clear an own-rx-busy condition and tell the peer about this, provided 341 * that there is a significant amount of free receive buffer space available. 342 */ 343 void x25_check_rbuf(struct sock *sk) 344 { 345 struct x25_sock *x25 = x25_sk(sk); 346 347 if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) && 348 (x25->condition & X25_COND_OWN_RX_BUSY)) { 349 x25->condition &= ~X25_COND_OWN_RX_BUSY; 350 x25->condition &= ~X25_COND_ACK_PENDING; 351 x25->vl = x25->vr; 352 x25_write_internal(sk, X25_RR); 353 x25_stop_timer(sk); 354 } 355 } 356 357 /* 358 * Compare 2 calluserdata structures, used to find correct listening sockets 359 * when call user data is used. 360 */ 361 int x25_check_calluserdata(struct x25_calluserdata *ours, struct x25_calluserdata *theirs) 362 { 363 int i; 364 if (ours->cudlength != theirs->cudlength) 365 return 0; 366 367 for (i=0;i<ours->cudlength;i++) { 368 if (ours->cuddata[i] != theirs->cuddata[i]) { 369 return 0; 370 } 371 } 372 return 1; 373 } 374 375