1/* 2 * NET/ROM release 007 3 * 4 * This code REQUIRES 2.1.15 or higher/ NET3.038 5 * 6 * This module: 7 * This module is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * Most of this code is based on the SDL diagrams published in the 7th 13 * ARRL Computer Networking Conference papers. The diagrams have mistakes 14 * in them, but are mostly correct. Before you modify the code could you 15 * read the SDL diagrams as the code is not obvious and probably very 16 * easy to break; 17 * 18 * History 19 * NET/ROM 001 Jonathan(G4KLX) Cloned from ax25_in.c 20 * NET/ROM 003 Jonathan(G4KLX) Added NET/ROM fragment reception. 21 * Darryl(G7LED) Added missing INFO with NAK case, optimized 22 * INFOACK handling, removed reconnect on error. 23 * NET/ROM 006 Jonathan(G4KLX) Hdrincl removal changes. 24 * NET/ROM 007 Jonathan(G4KLX) New timer architecture. 25 */ 26 27#include <linux/errno.h> 28#include <linux/types.h> 29#include <linux/socket.h> 30#include <linux/in.h> 31#include <linux/kernel.h> 32#include <linux/sched.h> 33#include <linux/timer.h> 34#include <linux/string.h> 35#include <linux/sockios.h> 36#include <linux/net.h> 37#include <net/ax25.h> 38#include <linux/inet.h> 39#include <linux/netdevice.h> 40#include <linux/skbuff.h> 41#include <net/sock.h> 42#include <net/ip.h> /* For ip_rcv */ 43#include <asm/uaccess.h> 44#include <asm/system.h> 45#include <linux/fcntl.h> 46#include <linux/mm.h> 47#include <linux/interrupt.h> 48#include <net/netrom.h> 49 50static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more) 51{ 52 struct sk_buff *skbo, *skbn = skb; 53 54 skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN); 55 56 nr_start_idletimer(sk); 57 58 if (more) { 59 sk->protinfo.nr->fraglen += skb->len; 60 skb_queue_tail(&sk->protinfo.nr->frag_queue, skb); 61 return 0; 62 } 63 64 if (!more && sk->protinfo.nr->fraglen > 0) { /* End of fragment */ 65 sk->protinfo.nr->fraglen += skb->len; 66 skb_queue_tail(&sk->protinfo.nr->frag_queue, skb); 67 68 if ((skbn = alloc_skb(sk->protinfo.nr->fraglen, GFP_ATOMIC)) == NULL) 69 return 1; 70 71 skbn->h.raw = skbn->data; 72 73 while ((skbo = skb_dequeue(&sk->protinfo.nr->frag_queue)) != NULL) { 74 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len); 75 kfree_skb(skbo); 76 } 77 78 sk->protinfo.nr->fraglen = 0; 79 } 80 81 return sock_queue_rcv_skb(sk, skbn); 82} 83 84/* 85 * State machine for state 1, Awaiting Connection State. 86 * The handling of the timer(s) is in file nr_timer.c. 87 * Handling of state 0 and connection release is in netrom.c. 88 */ 89static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) 90{ 91 switch (frametype) { 92 93 case NR_CONNACK: 94 nr_stop_t1timer(sk); 95 nr_start_idletimer(sk); 96 sk->protinfo.nr->your_index = skb->data[17]; 97 sk->protinfo.nr->your_id = skb->data[18]; 98 sk->protinfo.nr->vs = 0; 99 sk->protinfo.nr->va = 0; 100 sk->protinfo.nr->vr = 0; 101 sk->protinfo.nr->vl = 0; 102 sk->protinfo.nr->state = NR_STATE_3; 103 sk->protinfo.nr->n2count = 0; 104 sk->protinfo.nr->window = skb->data[20]; 105 sk->state = TCP_ESTABLISHED; 106 if (!sk->dead) 107 sk->state_change(sk); 108 break; 109 110 case NR_CONNACK | NR_CHOKE_FLAG: 111 nr_disconnect(sk, ECONNREFUSED); 112 break; 113 114 default: 115 break; 116 } 117 118 return 0; 119} 120 121/* 122 * State machine for state 2, Awaiting Release State. 123 * The handling of the timer(s) is in file nr_timer.c 124 * Handling of state 0 and connection release is in netrom.c. 125 */ 126static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) 127{ 128 switch (frametype) { 129 130 case NR_CONNACK | NR_CHOKE_FLAG: 131 nr_disconnect(sk, ECONNRESET); 132 break; 133 134 case NR_DISCREQ: 135 nr_write_internal(sk, NR_DISCACK); 136 137 case NR_DISCACK: 138 nr_disconnect(sk, 0); 139 break; 140 141 default: 142 break; 143 } 144 145 return 0; 146} 147 148/* 149 * State machine for state 3, Connected State. 150 * The handling of the timer(s) is in file nr_timer.c 151 * Handling of state 0 and connection release is in netrom.c. 152 */ 153static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype) 154{ 155 struct sk_buff_head temp_queue; 156 struct sk_buff *skbn; 157 unsigned short save_vr; 158 unsigned short nr, ns; 159 int queued = 0; 160 161 nr = skb->data[18]; 162 ns = skb->data[17]; 163 164 switch (frametype) { 165 166 case NR_CONNREQ: 167 nr_write_internal(sk, NR_CONNACK); 168 break; 169 170 case NR_DISCREQ: 171 nr_write_internal(sk, NR_DISCACK); 172 nr_disconnect(sk, 0); 173 break; 174 175 case NR_CONNACK | NR_CHOKE_FLAG: 176 case NR_DISCACK: 177 nr_disconnect(sk, ECONNRESET); 178 break; 179 180 case NR_INFOACK: 181 case NR_INFOACK | NR_CHOKE_FLAG: 182 case NR_INFOACK | NR_NAK_FLAG: 183 case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG: 184 if (frametype & NR_CHOKE_FLAG) { 185 sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY; 186 nr_start_t4timer(sk); 187 } else { 188 sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY; 189 nr_stop_t4timer(sk); 190 } 191 if (!nr_validate_nr(sk, nr)) { 192 break; 193 } 194 if (frametype & NR_NAK_FLAG) { 195 nr_frames_acked(sk, nr); 196 nr_send_nak_frame(sk); 197 } else { 198 if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) { 199 nr_frames_acked(sk, nr); 200 } else { 201 nr_check_iframes_acked(sk, nr); 202 } 203 } 204 break; 205 206 case NR_INFO: 207 case NR_INFO | NR_NAK_FLAG: 208 case NR_INFO | NR_CHOKE_FLAG: 209 case NR_INFO | NR_MORE_FLAG: 210 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG: 211 case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG: 212 case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG: 213 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG: 214 if (frametype & NR_CHOKE_FLAG) { 215 sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY; 216 nr_start_t4timer(sk); 217 } else { 218 sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY; 219 nr_stop_t4timer(sk); 220 } 221 if (nr_validate_nr(sk, nr)) { 222 if (frametype & NR_NAK_FLAG) { 223 nr_frames_acked(sk, nr); 224 nr_send_nak_frame(sk); 225 } else { 226 if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) { 227 nr_frames_acked(sk, nr); 228 } else { 229 nr_check_iframes_acked(sk, nr); 230 } 231 } 232 } 233 queued = 1; 234 skb_queue_head(&sk->protinfo.nr->reseq_queue, skb); 235 if (sk->protinfo.nr->condition & NR_COND_OWN_RX_BUSY) 236 break; 237 skb_queue_head_init(&temp_queue); 238 do { 239 save_vr = sk->protinfo.nr->vr; 240 while ((skbn = skb_dequeue(&sk->protinfo.nr->reseq_queue)) != NULL) { 241 ns = skbn->data[17]; 242 if (ns == sk->protinfo.nr->vr) { 243 if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) { 244 sk->protinfo.nr->vr = (sk->protinfo.nr->vr + 1) % NR_MODULUS; 245 } else { 246 sk->protinfo.nr->condition |= NR_COND_OWN_RX_BUSY; 247 skb_queue_tail(&temp_queue, skbn); 248 } 249 } else if (nr_in_rx_window(sk, ns)) { 250 skb_queue_tail(&temp_queue, skbn); 251 } else { 252 kfree_skb(skbn); 253 } 254 } 255 while ((skbn = skb_dequeue(&temp_queue)) != NULL) { 256 skb_queue_tail(&sk->protinfo.nr->reseq_queue, skbn); 257 } 258 } while (save_vr != sk->protinfo.nr->vr); 259 /* 260 * Window is full, ack it immediately. 261 */ 262 if (((sk->protinfo.nr->vl + sk->protinfo.nr->window) % NR_MODULUS) == sk->protinfo.nr->vr) { 263 nr_enquiry_response(sk); 264 } else { 265 if (!(sk->protinfo.nr->condition & NR_COND_ACK_PENDING)) { 266 sk->protinfo.nr->condition |= NR_COND_ACK_PENDING; 267 nr_start_t2timer(sk); 268 } 269 } 270 break; 271 272 default: 273 break; 274 } 275 276 return queued; 277} 278 279/* Higher level upcall for a LAPB frame */ 280int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb) 281{ 282 int queued = 0, frametype; 283 284 if (sk->protinfo.nr->state == NR_STATE_0) 285 return 0; 286 287 frametype = skb->data[19]; 288 289 switch (sk->protinfo.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