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/timer.h> 16 #include <linux/string.h> 17 #include <linux/sockios.h> 18 #include <linux/net.h> 19 #include <linux/slab.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 skb_reset_transport_header(skbn); 56 57 while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) { 58 skb_copy_from_linear_data(skbo, 59 skb_put(skbn, skbo->len), 60 skbo->len); 61 kfree_skb(skbo); 62 } 63 64 nr->fraglen = 0; 65 } 66 67 return sock_queue_rcv_skb(sk, skbn); 68 } 69 70 /* 71 * State machine for state 1, Awaiting Connection State. 72 * The handling of the timer(s) is in file nr_timer.c. 73 * Handling of state 0 and connection release is in netrom.c. 74 */ 75 static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, 76 int frametype) 77 { 78 switch (frametype) { 79 case NR_CONNACK: { 80 struct nr_sock *nr = nr_sk(sk); 81 82 nr_stop_t1timer(sk); 83 nr_start_idletimer(sk); 84 nr->your_index = skb->data[17]; 85 nr->your_id = skb->data[18]; 86 nr->vs = 0; 87 nr->va = 0; 88 nr->vr = 0; 89 nr->vl = 0; 90 nr->state = NR_STATE_3; 91 nr->n2count = 0; 92 nr->window = skb->data[20]; 93 sk->sk_state = TCP_ESTABLISHED; 94 if (!sock_flag(sk, SOCK_DEAD)) 95 sk->sk_state_change(sk); 96 break; 97 } 98 99 case NR_CONNACK | NR_CHOKE_FLAG: 100 nr_disconnect(sk, ECONNREFUSED); 101 break; 102 103 case NR_RESET: 104 if (sysctl_netrom_reset_circuit) 105 nr_disconnect(sk, ECONNRESET); 106 break; 107 108 default: 109 break; 110 } 111 return 0; 112 } 113 114 /* 115 * State machine for state 2, Awaiting Release State. 116 * The handling of the timer(s) is in file nr_timer.c 117 * Handling of state 0 and connection release is in netrom.c. 118 */ 119 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, 120 int frametype) 121 { 122 switch (frametype) { 123 case NR_CONNACK | NR_CHOKE_FLAG: 124 nr_disconnect(sk, ECONNRESET); 125 break; 126 127 case NR_DISCREQ: 128 nr_write_internal(sk, NR_DISCACK); 129 130 case NR_DISCACK: 131 nr_disconnect(sk, 0); 132 break; 133 134 case NR_RESET: 135 if (sysctl_netrom_reset_circuit) 136 nr_disconnect(sk, ECONNRESET); 137 break; 138 139 default: 140 break; 141 } 142 return 0; 143 } 144 145 /* 146 * State machine for state 3, Connected State. 147 * The handling of the timer(s) is in file nr_timer.c 148 * Handling of state 0 and connection release is in netrom.c. 149 */ 150 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype) 151 { 152 struct nr_sock *nrom = nr_sk(sk); 153 struct sk_buff_head temp_queue; 154 struct sk_buff *skbn; 155 unsigned short save_vr; 156 unsigned short nr, ns; 157 int queued = 0; 158 159 nr = skb->data[18]; 160 ns = skb->data[17]; 161 162 switch (frametype) { 163 case NR_CONNREQ: 164 nr_write_internal(sk, NR_CONNACK); 165 break; 166 167 case NR_DISCREQ: 168 nr_write_internal(sk, NR_DISCACK); 169 nr_disconnect(sk, 0); 170 break; 171 172 case NR_CONNACK | NR_CHOKE_FLAG: 173 case NR_DISCACK: 174 nr_disconnect(sk, ECONNRESET); 175 break; 176 177 case NR_INFOACK: 178 case NR_INFOACK | NR_CHOKE_FLAG: 179 case NR_INFOACK | NR_NAK_FLAG: 180 case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG: 181 if (frametype & NR_CHOKE_FLAG) { 182 nrom->condition |= NR_COND_PEER_RX_BUSY; 183 nr_start_t4timer(sk); 184 } else { 185 nrom->condition &= ~NR_COND_PEER_RX_BUSY; 186 nr_stop_t4timer(sk); 187 } 188 if (!nr_validate_nr(sk, nr)) { 189 break; 190 } 191 if (frametype & NR_NAK_FLAG) { 192 nr_frames_acked(sk, nr); 193 nr_send_nak_frame(sk); 194 } else { 195 if (nrom->condition & NR_COND_PEER_RX_BUSY) { 196 nr_frames_acked(sk, nr); 197 } else { 198 nr_check_iframes_acked(sk, nr); 199 } 200 } 201 break; 202 203 case NR_INFO: 204 case NR_INFO | NR_NAK_FLAG: 205 case NR_INFO | NR_CHOKE_FLAG: 206 case NR_INFO | NR_MORE_FLAG: 207 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG: 208 case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG: 209 case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG: 210 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG: 211 if (frametype & NR_CHOKE_FLAG) { 212 nrom->condition |= NR_COND_PEER_RX_BUSY; 213 nr_start_t4timer(sk); 214 } else { 215 nrom->condition &= ~NR_COND_PEER_RX_BUSY; 216 nr_stop_t4timer(sk); 217 } 218 if (nr_validate_nr(sk, nr)) { 219 if (frametype & NR_NAK_FLAG) { 220 nr_frames_acked(sk, nr); 221 nr_send_nak_frame(sk); 222 } else { 223 if (nrom->condition & NR_COND_PEER_RX_BUSY) { 224 nr_frames_acked(sk, nr); 225 } else { 226 nr_check_iframes_acked(sk, nr); 227 } 228 } 229 } 230 queued = 1; 231 skb_queue_head(&nrom->reseq_queue, skb); 232 if (nrom->condition & NR_COND_OWN_RX_BUSY) 233 break; 234 skb_queue_head_init(&temp_queue); 235 do { 236 save_vr = nrom->vr; 237 while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) { 238 ns = skbn->data[17]; 239 if (ns == nrom->vr) { 240 if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) { 241 nrom->vr = (nrom->vr + 1) % NR_MODULUS; 242 } else { 243 nrom->condition |= NR_COND_OWN_RX_BUSY; 244 skb_queue_tail(&temp_queue, skbn); 245 } 246 } else if (nr_in_rx_window(sk, ns)) { 247 skb_queue_tail(&temp_queue, skbn); 248 } else { 249 kfree_skb(skbn); 250 } 251 } 252 while ((skbn = skb_dequeue(&temp_queue)) != NULL) { 253 skb_queue_tail(&nrom->reseq_queue, skbn); 254 } 255 } while (save_vr != nrom->vr); 256 /* 257 * Window is full, ack it immediately. 258 */ 259 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) { 260 nr_enquiry_response(sk); 261 } else { 262 if (!(nrom->condition & NR_COND_ACK_PENDING)) { 263 nrom->condition |= NR_COND_ACK_PENDING; 264 nr_start_t2timer(sk); 265 } 266 } 267 break; 268 269 case NR_RESET: 270 if (sysctl_netrom_reset_circuit) 271 nr_disconnect(sk, ECONNRESET); 272 break; 273 274 default: 275 break; 276 } 277 return queued; 278 } 279 280 /* Higher level upcall for a LAPB frame - called with sk locked */ 281 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb) 282 { 283 struct nr_sock *nr = nr_sk(sk); 284 int queued = 0, frametype; 285 286 if (nr->state == NR_STATE_0) 287 return 0; 288 289 frametype = skb->data[19]; 290 291 switch (nr->state) { 292 case NR_STATE_1: 293 queued = nr_state1_machine(sk, skb, frametype); 294 break; 295 case NR_STATE_2: 296 queued = nr_state2_machine(sk, skb, frametype); 297 break; 298 case NR_STATE_3: 299 queued = nr_state3_machine(sk, skb, frametype); 300 break; 301 } 302 303 nr_kick(sk); 304 305 return queued; 306 } 307