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 default: 102 break; 103 } 104 return 0; 105 } 106 107 /* 108 * State machine for state 2, Awaiting Release State. 109 * The handling of the timer(s) is in file nr_timer.c 110 * Handling of state 0 and connection release is in netrom.c. 111 */ 112 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, 113 int frametype) 114 { 115 switch (frametype) { 116 case NR_CONNACK | NR_CHOKE_FLAG: 117 nr_disconnect(sk, ECONNRESET); 118 break; 119 120 case NR_DISCREQ: 121 nr_write_internal(sk, NR_DISCACK); 122 123 case NR_DISCACK: 124 nr_disconnect(sk, 0); 125 break; 126 127 default: 128 break; 129 } 130 return 0; 131 } 132 133 /* 134 * State machine for state 3, Connected State. 135 * The handling of the timer(s) is in file nr_timer.c 136 * Handling of state 0 and connection release is in netrom.c. 137 */ 138 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype) 139 { 140 struct nr_sock *nrom = nr_sk(sk); 141 struct sk_buff_head temp_queue; 142 struct sk_buff *skbn; 143 unsigned short save_vr; 144 unsigned short nr, ns; 145 int queued = 0; 146 147 nr = skb->data[18]; 148 ns = skb->data[17]; 149 150 switch (frametype) { 151 case NR_CONNREQ: 152 nr_write_internal(sk, NR_CONNACK); 153 break; 154 155 case NR_DISCREQ: 156 nr_write_internal(sk, NR_DISCACK); 157 nr_disconnect(sk, 0); 158 break; 159 160 case NR_CONNACK | NR_CHOKE_FLAG: 161 case NR_DISCACK: 162 nr_disconnect(sk, ECONNRESET); 163 break; 164 165 case NR_INFOACK: 166 case NR_INFOACK | NR_CHOKE_FLAG: 167 case NR_INFOACK | NR_NAK_FLAG: 168 case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG: 169 if (frametype & NR_CHOKE_FLAG) { 170 nrom->condition |= NR_COND_PEER_RX_BUSY; 171 nr_start_t4timer(sk); 172 } else { 173 nrom->condition &= ~NR_COND_PEER_RX_BUSY; 174 nr_stop_t4timer(sk); 175 } 176 if (!nr_validate_nr(sk, nr)) { 177 break; 178 } 179 if (frametype & NR_NAK_FLAG) { 180 nr_frames_acked(sk, nr); 181 nr_send_nak_frame(sk); 182 } else { 183 if (nrom->condition & NR_COND_PEER_RX_BUSY) { 184 nr_frames_acked(sk, nr); 185 } else { 186 nr_check_iframes_acked(sk, nr); 187 } 188 } 189 break; 190 191 case NR_INFO: 192 case NR_INFO | NR_NAK_FLAG: 193 case NR_INFO | NR_CHOKE_FLAG: 194 case NR_INFO | NR_MORE_FLAG: 195 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG: 196 case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG: 197 case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG: 198 case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG: 199 if (frametype & NR_CHOKE_FLAG) { 200 nrom->condition |= NR_COND_PEER_RX_BUSY; 201 nr_start_t4timer(sk); 202 } else { 203 nrom->condition &= ~NR_COND_PEER_RX_BUSY; 204 nr_stop_t4timer(sk); 205 } 206 if (nr_validate_nr(sk, nr)) { 207 if (frametype & NR_NAK_FLAG) { 208 nr_frames_acked(sk, nr); 209 nr_send_nak_frame(sk); 210 } else { 211 if (nrom->condition & NR_COND_PEER_RX_BUSY) { 212 nr_frames_acked(sk, nr); 213 } else { 214 nr_check_iframes_acked(sk, nr); 215 } 216 } 217 } 218 queued = 1; 219 skb_queue_head(&nrom->reseq_queue, skb); 220 if (nrom->condition & NR_COND_OWN_RX_BUSY) 221 break; 222 skb_queue_head_init(&temp_queue); 223 do { 224 save_vr = nrom->vr; 225 while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) { 226 ns = skbn->data[17]; 227 if (ns == nrom->vr) { 228 if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) { 229 nrom->vr = (nrom->vr + 1) % NR_MODULUS; 230 } else { 231 nrom->condition |= NR_COND_OWN_RX_BUSY; 232 skb_queue_tail(&temp_queue, skbn); 233 } 234 } else if (nr_in_rx_window(sk, ns)) { 235 skb_queue_tail(&temp_queue, skbn); 236 } else { 237 kfree_skb(skbn); 238 } 239 } 240 while ((skbn = skb_dequeue(&temp_queue)) != NULL) { 241 skb_queue_tail(&nrom->reseq_queue, skbn); 242 } 243 } while (save_vr != nrom->vr); 244 /* 245 * Window is full, ack it immediately. 246 */ 247 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) { 248 nr_enquiry_response(sk); 249 } else { 250 if (!(nrom->condition & NR_COND_ACK_PENDING)) { 251 nrom->condition |= NR_COND_ACK_PENDING; 252 nr_start_t2timer(sk); 253 } 254 } 255 break; 256 257 default: 258 break; 259 } 260 return queued; 261 } 262 263 /* Higher level upcall for a LAPB frame - called with sk locked */ 264 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb) 265 { 266 struct nr_sock *nr = nr_sk(sk); 267 int queued = 0, frametype; 268 269 if (nr->state == NR_STATE_0) 270 return 0; 271 272 frametype = skb->data[19]; 273 274 switch (nr->state) { 275 case NR_STATE_1: 276 queued = nr_state1_machine(sk, skb, frametype); 277 break; 278 case NR_STATE_2: 279 queued = nr_state2_machine(sk, skb, frametype); 280 break; 281 case NR_STATE_3: 282 queued = nr_state3_machine(sk, skb, frametype); 283 break; 284 } 285 286 nr_kick(sk); 287 288 return queued; 289 } 290