1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License as published by 4 * the Free Software Foundation; either version 2 of the License, or 5 * (at your option) any later version. 6 * 7 * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) 8 * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk) 9 */ 10 #include <linux/errno.h> 11 #include <linux/types.h> 12 #include <linux/socket.h> 13 #include <linux/in.h> 14 #include <linux/kernel.h> 15 #include <linux/sched.h> 16 #include <linux/timer.h> 17 #include <linux/string.h> 18 #include <linux/sockios.h> 19 #include <linux/net.h> 20 #include <net/ax25.h> 21 #include <linux/inet.h> 22 #include <linux/netdevice.h> 23 #include <linux/skbuff.h> 24 #include <net/sock.h> 25 #include <net/tcp_states.h> 26 #include <asm/uaccess.h> 27 #include <asm/system.h> 28 #include <linux/fcntl.h> 29 #include <linux/mm.h> 30 #include <linux/interrupt.h> 31 #include <net/netrom.h> 32 33 static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more) 34 { 35 struct sk_buff *skbo, *skbn = skb; 36 struct nr_sock *nr = nr_sk(sk); 37 38 skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN); 39 40 nr_start_idletimer(sk); 41 42 if (more) { 43 nr->fraglen += skb->len; 44 skb_queue_tail(&nr->frag_queue, skb); 45 return 0; 46 } 47 48 if (!more && nr->fraglen > 0) { /* End of fragment */ 49 nr->fraglen += skb->len; 50 skb_queue_tail(&nr->frag_queue, skb); 51 52 if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL) 53 return 1; 54 55 skbn->h.raw = skbn->data; 56 57 while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) { 58 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len); 59 kfree_skb(skbo); 60 } 61 62 nr->fraglen = 0; 63 } 64 65 return sock_queue_rcv_skb(sk, skbn); 66 } 67 68 /* 69 * State machine for state 1, Awaiting Connection State. 70 * The handling of the timer(s) is in file nr_timer.c. 71 * Handling of state 0 and connection release is in netrom.c. 72 */ 73 static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, 74 int frametype) 75 { 76 switch (frametype) { 77 case NR_CONNACK: { 78 struct nr_sock *nr = nr_sk(sk); 79 80 nr_stop_t1timer(sk); 81 nr_start_idletimer(sk); 82 nr->your_index = skb->data[17]; 83 nr->your_id = skb->data[18]; 84 nr->vs = 0; 85 nr->va = 0; 86 nr->vr = 0; 87 nr->vl = 0; 88 nr->state = NR_STATE_3; 89 nr->n2count = 0; 90 nr->window = skb->data[20]; 91 sk->sk_state = TCP_ESTABLISHED; 92 if (!sock_flag(sk, SOCK_DEAD)) 93 sk->sk_state_change(sk); 94 break; 95 } 96 97 case NR_CONNACK | NR_CHOKE_FLAG: 98 nr_disconnect(sk, ECONNREFUSED); 99 break; 100 101 case NR_RESET: 102 if (sysctl_netrom_reset_circuit); 103 nr_disconnect(sk, ECONNRESET); 104 break; 105 106 default: 107 break; 108 } 109 return 0; 110 } 111 112 /* 113 * State machine for state 2, Awaiting Release State. 114 * The handling of the timer(s) is in file nr_timer.c 115 * Handling of state 0 and connection release is in netrom.c. 116 */ 117 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, 118 int frametype) 119 { 120 switch (frametype) { 121 case NR_CONNACK | NR_CHOKE_FLAG: 122 nr_disconnect(sk, ECONNRESET); 123 break; 124 125 case NR_DISCREQ: 126 nr_write_internal(sk, NR_DISCACK); 127 128 case NR_DISCACK: 129 nr_disconnect(sk, 0); 130 break; 131 132 case NR_RESET: 133 if (sysctl_netrom_reset_circuit); 134 nr_disconnect(sk, ECONNRESET); 135 break; 136 137 default: 138 break; 139 } 140 return 0; 141 } 142 143 /* 144 * State machine for state 3, Connected State. 145 * The handling of the timer(s) is in file nr_timer.c 146 * Handling of state 0 and connection release is in netrom.c. 147 */ 148 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype) 149 { 150 struct nr_sock *nrom = nr_sk(sk); 151 struct sk_buff_head temp_queue; 152 struct sk_buff *skbn; 153 unsigned short save_vr; 154 unsigned short nr, ns; 155 int queued = 0; 156 157 nr = skb->data[18]; 158 ns = skb->data[17]; 159 160 switch (frametype) { 161 case NR_CONNREQ: 162 nr_write_internal(sk, NR_CONNACK); 163 break; 164 165 case NR_DISCREQ: 166 nr_write_internal(sk, NR_DISCACK); 167 nr_disconnect(sk, 0); 168 break; 169 170 case NR_CONNACK | NR_CHOKE_FLAG: 171 case NR_DISCACK: 172 nr_disconnect(sk, ECONNRESET); 173 break; 174 175 case NR_INFOACK: 176 case NR_INFOACK | NR_CHOKE_FLAG: 177 case NR_INFOACK | NR_NAK_FLAG: 178 case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG: 179 if (frametype & NR_CHOKE_FLAG) { 180 nrom->condition |= NR_COND_PEER_RX_BUSY; 181 nr_start_t4timer(sk); 182 } else { 183 nrom->condition &= ~NR_COND_PEER_RX_BUSY; 184 nr_stop_t4timer(sk); 185 } 186 if (!nr_validate_nr(sk, nr)) { 187 break; 188 } 189 if (frametype & NR_NAK_FLAG) { 190 nr_frames_acked(sk, nr); 191 nr_send_nak_frame(sk); 192 } else { 193 if (nrom->condition & NR_COND_PEER_RX_BUSY) { 194 nr_frames_acked(sk, nr); 195 } else { 196 nr_check_iframes_acked(sk, nr); 197 } 198 } 199 break; 200 201 case NR_INFO: 202 case NR_INFO | NR_NAK_FLAG: 203 case NR_INFO | NR_CHOKE_FLAG: 204 case NR_INFO | NR_MORE_FLAG: 205 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG: 206 case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG: 207 case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG: 208 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG: 209 if (frametype & NR_CHOKE_FLAG) { 210 nrom->condition |= NR_COND_PEER_RX_BUSY; 211 nr_start_t4timer(sk); 212 } else { 213 nrom->condition &= ~NR_COND_PEER_RX_BUSY; 214 nr_stop_t4timer(sk); 215 } 216 if (nr_validate_nr(sk, nr)) { 217 if (frametype & NR_NAK_FLAG) { 218 nr_frames_acked(sk, nr); 219 nr_send_nak_frame(sk); 220 } else { 221 if (nrom->condition & NR_COND_PEER_RX_BUSY) { 222 nr_frames_acked(sk, nr); 223 } else { 224 nr_check_iframes_acked(sk, nr); 225 } 226 } 227 } 228 queued = 1; 229 skb_queue_head(&nrom->reseq_queue, skb); 230 if (nrom->condition & NR_COND_OWN_RX_BUSY) 231 break; 232 skb_queue_head_init(&temp_queue); 233 do { 234 save_vr = nrom->vr; 235 while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) { 236 ns = skbn->data[17]; 237 if (ns == nrom->vr) { 238 if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) { 239 nrom->vr = (nrom->vr + 1) % NR_MODULUS; 240 } else { 241 nrom->condition |= NR_COND_OWN_RX_BUSY; 242 skb_queue_tail(&temp_queue, skbn); 243 } 244 } else if (nr_in_rx_window(sk, ns)) { 245 skb_queue_tail(&temp_queue, skbn); 246 } else { 247 kfree_skb(skbn); 248 } 249 } 250 while ((skbn = skb_dequeue(&temp_queue)) != NULL) { 251 skb_queue_tail(&nrom->reseq_queue, skbn); 252 } 253 } while (save_vr != nrom->vr); 254 /* 255 * Window is full, ack it immediately. 256 */ 257 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) { 258 nr_enquiry_response(sk); 259 } else { 260 if (!(nrom->condition & NR_COND_ACK_PENDING)) { 261 nrom->condition |= NR_COND_ACK_PENDING; 262 nr_start_t2timer(sk); 263 } 264 } 265 break; 266 267 case NR_RESET: 268 if (sysctl_netrom_reset_circuit); 269 nr_disconnect(sk, ECONNRESET); 270 break; 271 272 default: 273 break; 274 } 275 return queued; 276 } 277 278 /* Higher level upcall for a LAPB frame - called with sk locked */ 279 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb) 280 { 281 struct nr_sock *nr = nr_sk(sk); 282 int queued = 0, frametype; 283 284 if (nr->state == NR_STATE_0) 285 return 0; 286 287 frametype = skb->data[19]; 288 289 switch (nr->state) { 290 case NR_STATE_1: 291 queued = nr_state1_machine(sk, skb, frametype); 292 break; 293 case NR_STATE_2: 294 queued = nr_state2_machine(sk, skb, frametype); 295 break; 296 case NR_STATE_3: 297 queued = nr_state3_machine(sk, skb, frametype); 298 break; 299 } 300 301 nr_kick(sk); 302 303 return queued; 304 } 305