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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 | // SPDX-License-Identifier: GPL-2.0-or-later /* * X.25 Packet Layer release 002 * * This is ALPHA test software. This code may break your machine, * randomly fail to work with new releases, misbehave and/or generally * screw up. It might even work. * * This code REQUIRES 2.1.15 or higher * * History * X.25 001 Jonathan Naylor Started coding. * X.25 002 Jonathan Naylor Centralised disconnection code. * New timer architecture. * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities * negotiation. * 2000-11-10 Henner Eisen Check and reset for out-of-sequence * i-frames. */ #define pr_fmt(fmt) "X25: " fmt #include <linux/slab.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/skbuff.h> #include <net/sock.h> #include <net/tcp_states.h> #include <net/x25.h> static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more) { struct sk_buff *skbo, *skbn = skb; struct x25_sock *x25 = x25_sk(sk); if (more) { x25->fraglen += skb->len; skb_queue_tail(&x25->fragment_queue, skb); skb_set_owner_r(skb, sk); return 0; } if (!more && x25->fraglen > 0) { /* End of fragment */ int len = x25->fraglen + skb->len; if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){ kfree_skb(skb); return 1; } skb_queue_tail(&x25->fragment_queue, skb); skb_reset_transport_header(skbn); skbo = skb_dequeue(&x25->fragment_queue); skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len), skbo->len); kfree_skb(skbo); while ((skbo = skb_dequeue(&x25->fragment_queue)) != NULL) { skb_pull(skbo, (x25->neighbour->extended) ? X25_EXT_MIN_LEN : X25_STD_MIN_LEN); skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len), skbo->len); kfree_skb(skbo); } x25->fraglen = 0; } skb_set_owner_r(skbn, sk); skb_queue_tail(&sk->sk_receive_queue, skbn); if (!sock_flag(sk, SOCK_DEAD)) sk->sk_data_ready(sk); return 0; } /* * State machine for state 1, Awaiting Call Accepted State. * The handling of the timer(s) is in file x25_timer.c. * Handling of state 0 and connection release is in af_x25.c. */ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct x25_address source_addr, dest_addr; int len; struct x25_sock *x25 = x25_sk(sk); switch (frametype) { case X25_CALL_ACCEPTED: { x25_stop_timer(sk); x25->condition = 0x00; x25->vs = 0; x25->va = 0; x25->vr = 0; x25->vl = 0; x25->state = X25_STATE_3; sk->sk_state = TCP_ESTABLISHED; /* * Parse the data in the frame. */ if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) goto out_clear; skb_pull(skb, X25_STD_MIN_LEN); len = x25_parse_address_block(skb, &source_addr, &dest_addr); if (len > 0) skb_pull(skb, len); else if (len < 0) goto out_clear; len = x25_parse_facilities(skb, &x25->facilities, &x25->dte_facilities, &x25->vc_facil_mask); if (len > 0) skb_pull(skb, len); else if (len < 0) goto out_clear; /* * Copy any Call User Data. */ if (skb->len > 0) { if (skb->len > X25_MAX_CUD_LEN) goto out_clear; skb_copy_bits(skb, 0, x25->calluserdata.cuddata, skb->len); x25->calluserdata.cudlength = skb->len; } if (!sock_flag(sk, SOCK_DEAD)) sk->sk_state_change(sk); break; } case X25_CALL_REQUEST: /* call collision */ x25->causediag.cause = 0x01; x25->causediag.diagnostic = 0x48; x25_write_internal(sk, X25_CLEAR_REQUEST); x25_disconnect(sk, EISCONN, 0x01, 0x48); break; case X25_CLEAR_REQUEST: if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) goto out_clear; x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); break; default: break; } return 0; out_clear: x25_write_internal(sk, X25_CLEAR_REQUEST); x25->state = X25_STATE_2; x25_start_t23timer(sk); return 0; } /* * State machine for state 2, Awaiting Clear Confirmation State. * The handling of the timer(s) is in file x25_timer.c * Handling of state 0 and connection release is in af_x25.c. */ static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) { switch (frametype) { case X25_CLEAR_REQUEST: if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) goto out_clear; x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, 0, skb->data[3], skb->data[4]); break; case X25_CLEAR_CONFIRMATION: x25_disconnect(sk, 0, 0, 0); break; default: break; } return 0; out_clear: x25_write_internal(sk, X25_CLEAR_REQUEST); x25_start_t23timer(sk); return 0; } /* * State machine for state 3, Connected State. * The handling of the timer(s) is in file x25_timer.c * Handling of state 0 and connection release is in af_x25.c. */ static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) { int queued = 0; int modulus; struct x25_sock *x25 = x25_sk(sk); modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS; switch (frametype) { case X25_RESET_REQUEST: x25_write_internal(sk, X25_RESET_CONFIRMATION); x25_stop_timer(sk); x25->condition = 0x00; x25->vs = 0; x25->vr = 0; x25->va = 0; x25->vl = 0; x25_requeue_frames(sk); break; case X25_CLEAR_REQUEST: if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) goto out_clear; x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, 0, skb->data[3], skb->data[4]); break; case X25_RR: case X25_RNR: if (!x25_validate_nr(sk, nr)) { x25_clear_queues(sk); x25_write_internal(sk, X25_RESET_REQUEST); x25_start_t22timer(sk); x25->condition = 0x00; x25->vs = 0; x25->vr = 0; x25->va = 0; x25->vl = 0; x25->state = X25_STATE_4; } else { x25_frames_acked(sk, nr); if (frametype == X25_RNR) { x25->condition |= X25_COND_PEER_RX_BUSY; } else { x25->condition &= ~X25_COND_PEER_RX_BUSY; } } break; case X25_DATA: /* XXX */ x25->condition &= ~X25_COND_PEER_RX_BUSY; if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) { x25_clear_queues(sk); x25_write_internal(sk, X25_RESET_REQUEST); x25_start_t22timer(sk); x25->condition = 0x00; x25->vs = 0; x25->vr = 0; x25->va = 0; x25->vl = 0; x25->state = X25_STATE_4; break; } x25_frames_acked(sk, nr); if (ns == x25->vr) { if (x25_queue_rx_frame(sk, skb, m) == 0) { x25->vr = (x25->vr + 1) % modulus; queued = 1; } else { /* Should never happen */ x25_clear_queues(sk); x25_write_internal(sk, X25_RESET_REQUEST); x25_start_t22timer(sk); x25->condition = 0x00; x25->vs = 0; x25->vr = 0; x25->va = 0; x25->vl = 0; x25->state = X25_STATE_4; break; } if (atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1)) x25->condition |= X25_COND_OWN_RX_BUSY; } /* * If the window is full Ack it immediately, else * start the holdback timer. */ if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) { x25->condition &= ~X25_COND_ACK_PENDING; x25_stop_timer(sk); x25_enquiry_response(sk); } else { x25->condition |= X25_COND_ACK_PENDING; x25_start_t2timer(sk); } break; case X25_INTERRUPT_CONFIRMATION: clear_bit(X25_INTERRUPT_FLAG, &x25->flags); break; case X25_INTERRUPT: if (sock_flag(sk, SOCK_URGINLINE)) queued = !sock_queue_rcv_skb(sk, skb); else { skb_set_owner_r(skb, sk); skb_queue_tail(&x25->interrupt_in_queue, skb); queued = 1; } sk_send_sigurg(sk); x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION); break; default: pr_warn("unknown %02X in state 3\n", frametype); break; } return queued; out_clear: x25_write_internal(sk, X25_CLEAR_REQUEST); x25->state = X25_STATE_2; x25_start_t23timer(sk); return 0; } /* * State machine for state 4, Awaiting Reset Confirmation State. * The handling of the timer(s) is in file x25_timer.c * Handling of state 0 and connection release is in af_x25.c. */ static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct x25_sock *x25 = x25_sk(sk); switch (frametype) { case X25_RESET_REQUEST: x25_write_internal(sk, X25_RESET_CONFIRMATION); /* fall through */ case X25_RESET_CONFIRMATION: { x25_stop_timer(sk); x25->condition = 0x00; x25->va = 0; x25->vr = 0; x25->vs = 0; x25->vl = 0; x25->state = X25_STATE_3; x25_requeue_frames(sk); break; } case X25_CLEAR_REQUEST: if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) goto out_clear; x25_write_internal(sk, X25_CLEAR_CONFIRMATION); x25_disconnect(sk, 0, skb->data[3], skb->data[4]); break; default: break; } return 0; out_clear: x25_write_internal(sk, X25_CLEAR_REQUEST); x25->state = X25_STATE_2; x25_start_t23timer(sk); return 0; } /* Higher level upcall for a LAPB frame */ int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb) { struct x25_sock *x25 = x25_sk(sk); int queued = 0, frametype, ns, nr, q, d, m; if (x25->state == X25_STATE_0) return 0; frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m); switch (x25->state) { case X25_STATE_1: queued = x25_state1_machine(sk, skb, frametype); break; case X25_STATE_2: queued = x25_state2_machine(sk, skb, frametype); break; case X25_STATE_3: queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m); break; case X25_STATE_4: queued = x25_state4_machine(sk, skb, frametype); break; } x25_kick(sk); return queued; } int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb) { int queued = x25_process_rx_frame(sk, skb); if (!queued) kfree_skb(skb); return 0; } |