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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 | // SPDX-License-Identifier: GPL-2.0-or-later /* * * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) * * Most of this code is based on the SDL diagrams published in the 7th ARRL * Computer Networking Conference papers. The diagrams have mistakes in them, * but are mostly correct. Before you modify the code could you read the SDL * diagrams as the code is not obvious and probably very easy to break. */ #include <linux/errno.h> #include <linux/filter.h> #include <linux/types.h> #include <linux/socket.h> #include <linux/in.h> #include <linux/kernel.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 <net/tcp_states.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <net/rose.h> /* * State machine for state 1, Awaiting Call Accepted State. * The handling of the timer(s) is in file rose_timer.c. * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct rose_sock *rose = rose_sk(sk); switch (frametype) { case ROSE_CALL_ACCEPTED: rose_stop_timer(sk); rose_start_idletimer(sk); rose->condition = 0x00; rose->vs = 0; rose->va = 0; rose->vr = 0; rose->vl = 0; rose->state = ROSE_STATE_3; sk->sk_state = TCP_ESTABLISHED; if (!sock_flag(sk, SOCK_DEAD)) sk->sk_state_change(sk); break; case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); rose->neighbour->use--; break; default: break; } return 0; } /* * State machine for state 2, Awaiting Clear Confirmation State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct rose_sock *rose = rose_sk(sk); switch (frametype) { case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose->neighbour->use--; break; case ROSE_CLEAR_CONFIRMATION: rose_disconnect(sk, 0, -1, -1); rose->neighbour->use--; break; default: break; } return 0; } /* * State machine for state 3, Connected State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) { struct rose_sock *rose = rose_sk(sk); int queued = 0; switch (frametype) { case ROSE_RESET_REQUEST: rose_stop_timer(sk); rose_start_idletimer(sk); rose_write_internal(sk, ROSE_RESET_CONFIRMATION); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose_requeue_frames(sk); break; case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose->neighbour->use--; break; case ROSE_RR: case ROSE_RNR: if (!rose_validate_nr(sk, nr)) { rose_write_internal(sk, ROSE_RESET_REQUEST); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose->state = ROSE_STATE_4; rose_start_t2timer(sk); rose_stop_idletimer(sk); } else { rose_frames_acked(sk, nr); if (frametype == ROSE_RNR) { rose->condition |= ROSE_COND_PEER_RX_BUSY; } else { rose->condition &= ~ROSE_COND_PEER_RX_BUSY; } } break; case ROSE_DATA: /* XXX */ rose->condition &= ~ROSE_COND_PEER_RX_BUSY; if (!rose_validate_nr(sk, nr)) { rose_write_internal(sk, ROSE_RESET_REQUEST); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose->state = ROSE_STATE_4; rose_start_t2timer(sk); rose_stop_idletimer(sk); break; } rose_frames_acked(sk, nr); if (ns == rose->vr) { rose_start_idletimer(sk); if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 && __sock_queue_rcv_skb(sk, skb) == 0) { rose->vr = (rose->vr + 1) % ROSE_MODULUS; queued = 1; } else { /* Should never happen ! */ rose_write_internal(sk, ROSE_RESET_REQUEST); rose->condition = 0x00; rose->vs = 0; rose->vr = 0; rose->va = 0; rose->vl = 0; rose->state = ROSE_STATE_4; rose_start_t2timer(sk); rose_stop_idletimer(sk); break; } if (atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1)) rose->condition |= ROSE_COND_OWN_RX_BUSY; } /* * If the window is full, ack the frame, else start the * acknowledge hold back timer. */ if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) { rose->condition &= ~ROSE_COND_ACK_PENDING; rose_stop_timer(sk); rose_enquiry_response(sk); } else { rose->condition |= ROSE_COND_ACK_PENDING; rose_start_hbtimer(sk); } break; default: printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype); break; } return queued; } /* * State machine for state 4, Awaiting Reset Confirmation State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) { struct rose_sock *rose = rose_sk(sk); switch (frametype) { case ROSE_RESET_REQUEST: rose_write_internal(sk, ROSE_RESET_CONFIRMATION); fallthrough; case ROSE_RESET_CONFIRMATION: rose_stop_timer(sk); rose_start_idletimer(sk); rose->condition = 0x00; rose->va = 0; rose->vr = 0; rose->vs = 0; rose->vl = 0; rose->state = ROSE_STATE_3; rose_requeue_frames(sk); break; case ROSE_CLEAR_REQUEST: rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose->neighbour->use--; break; default: break; } return 0; } /* * State machine for state 5, Awaiting Call Acceptance State. * The handling of the timer(s) is in file rose_timer.c * Handling of state 0 and connection release is in af_rose.c. */ static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype) { if (frametype == ROSE_CLEAR_REQUEST) { rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION); rose_disconnect(sk, 0, skb->data[3], skb->data[4]); rose_sk(sk)->neighbour->use--; } return 0; } /* Higher level upcall for a LAPB frame */ int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb) { struct rose_sock *rose = rose_sk(sk); int queued = 0, frametype, ns, nr, q, d, m; if (rose->state == ROSE_STATE_0) return 0; frametype = rose_decode(skb, &ns, &nr, &q, &d, &m); switch (rose->state) { case ROSE_STATE_1: queued = rose_state1_machine(sk, skb, frametype); break; case ROSE_STATE_2: queued = rose_state2_machine(sk, skb, frametype); break; case ROSE_STATE_3: queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m); break; case ROSE_STATE_4: queued = rose_state4_machine(sk, skb, frametype); break; case ROSE_STATE_5: queued = rose_state5_machine(sk, skb, frametype); break; } rose_kick(sk); return queued; } |