Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * 6pack.c This module implements the 6pack protocol for kernel-based |
| 3 | * devices like TTY. It interfaces between a raw TTY and the |
| 4 | * kernel's AX.25 protocol layers. |
| 5 | * |
Jan Engelhardt | 96de0e2 | 2007-10-19 23:21:04 +0200 | [diff] [blame] | 6 | * Authors: Andreas Könsgen <ajk@iehk.rwth-aachen.de> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * Ralf Baechle DL5RB <ralf@linux-mips.org> |
| 8 | * |
| 9 | * Quite a lot of stuff "stolen" by Joerg Reuter from slip.c, written by |
| 10 | * |
| 11 | * Laurence Culhane, <loz@holmes.demon.co.uk> |
| 12 | * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org> |
| 13 | */ |
| 14 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/module.h> |
| 16 | #include <asm/system.h> |
| 17 | #include <asm/uaccess.h> |
| 18 | #include <linux/bitops.h> |
| 19 | #include <linux/string.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/interrupt.h> |
| 22 | #include <linux/in.h> |
| 23 | #include <linux/tty.h> |
| 24 | #include <linux/errno.h> |
| 25 | #include <linux/netdevice.h> |
| 26 | #include <linux/timer.h> |
| 27 | #include <net/ax25.h> |
| 28 | #include <linux/etherdevice.h> |
| 29 | #include <linux/skbuff.h> |
| 30 | #include <linux/rtnetlink.h> |
| 31 | #include <linux/spinlock.h> |
| 32 | #include <linux/if_arp.h> |
| 33 | #include <linux/init.h> |
| 34 | #include <linux/ip.h> |
| 35 | #include <linux/tcp.h> |
Matthew Wilcox | 6188e10 | 2008-04-18 22:21:05 -0400 | [diff] [blame] | 36 | #include <linux/semaphore.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #include <asm/atomic.h> |
| 38 | |
| 39 | #define SIXPACK_VERSION "Revision: 0.3.0" |
| 40 | |
| 41 | /* sixpack priority commands */ |
| 42 | #define SIXP_SEOF 0x40 /* start and end of a 6pack frame */ |
| 43 | #define SIXP_TX_URUN 0x48 /* transmit overrun */ |
| 44 | #define SIXP_RX_ORUN 0x50 /* receive overrun */ |
| 45 | #define SIXP_RX_BUF_OVL 0x58 /* receive buffer overflow */ |
| 46 | |
| 47 | #define SIXP_CHKSUM 0xFF /* valid checksum of a 6pack frame */ |
| 48 | |
| 49 | /* masks to get certain bits out of the status bytes sent by the TNC */ |
| 50 | |
| 51 | #define SIXP_CMD_MASK 0xC0 |
| 52 | #define SIXP_CHN_MASK 0x07 |
| 53 | #define SIXP_PRIO_CMD_MASK 0x80 |
| 54 | #define SIXP_STD_CMD_MASK 0x40 |
| 55 | #define SIXP_PRIO_DATA_MASK 0x38 |
| 56 | #define SIXP_TX_MASK 0x20 |
| 57 | #define SIXP_RX_MASK 0x10 |
| 58 | #define SIXP_RX_DCD_MASK 0x18 |
| 59 | #define SIXP_LEDS_ON 0x78 |
| 60 | #define SIXP_LEDS_OFF 0x60 |
| 61 | #define SIXP_CON 0x08 |
| 62 | #define SIXP_STA 0x10 |
| 63 | |
| 64 | #define SIXP_FOUND_TNC 0xe9 |
| 65 | #define SIXP_CON_ON 0x68 |
| 66 | #define SIXP_DCD_MASK 0x08 |
| 67 | #define SIXP_DAMA_OFF 0 |
| 68 | |
| 69 | /* default level 2 parameters */ |
| 70 | #define SIXP_TXDELAY (HZ/4) /* in 1 s */ |
| 71 | #define SIXP_PERSIST 50 /* in 256ths */ |
| 72 | #define SIXP_SLOTTIME (HZ/10) /* in 1 s */ |
| 73 | #define SIXP_INIT_RESYNC_TIMEOUT (3*HZ/2) /* in 1 s */ |
| 74 | #define SIXP_RESYNC_TIMEOUT 5*HZ /* in 1 s */ |
| 75 | |
| 76 | /* 6pack configuration. */ |
| 77 | #define SIXP_NRUNIT 31 /* MAX number of 6pack channels */ |
| 78 | #define SIXP_MTU 256 /* Default MTU */ |
| 79 | |
| 80 | enum sixpack_flags { |
| 81 | SIXPF_ERROR, /* Parity, etc. error */ |
| 82 | }; |
| 83 | |
| 84 | struct sixpack { |
| 85 | /* Various fields. */ |
| 86 | struct tty_struct *tty; /* ptr to TTY structure */ |
| 87 | struct net_device *dev; /* easy for intr handling */ |
| 88 | |
| 89 | /* These are pointers to the malloc()ed frame buffers. */ |
| 90 | unsigned char *rbuff; /* receiver buffer */ |
| 91 | int rcount; /* received chars counter */ |
| 92 | unsigned char *xbuff; /* transmitter buffer */ |
| 93 | unsigned char *xhead; /* next byte to XMIT */ |
| 94 | int xleft; /* bytes left in XMIT queue */ |
| 95 | |
| 96 | unsigned char raw_buf[4]; |
| 97 | unsigned char cooked_buf[400]; |
| 98 | |
| 99 | unsigned int rx_count; |
| 100 | unsigned int rx_count_cooked; |
| 101 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | int mtu; /* Our mtu (to spot changes!) */ |
| 103 | int buffsize; /* Max buffers sizes */ |
| 104 | |
| 105 | unsigned long flags; /* Flag values/ mode etc */ |
| 106 | unsigned char mode; /* 6pack mode */ |
| 107 | |
| 108 | /* 6pack stuff */ |
| 109 | unsigned char tx_delay; |
| 110 | unsigned char persistence; |
| 111 | unsigned char slottime; |
| 112 | unsigned char duplex; |
| 113 | unsigned char led_state; |
| 114 | unsigned char status; |
| 115 | unsigned char status1; |
| 116 | unsigned char status2; |
| 117 | unsigned char tx_enable; |
| 118 | unsigned char tnc_state; |
| 119 | |
| 120 | struct timer_list tx_t; |
| 121 | struct timer_list resync_t; |
| 122 | atomic_t refcnt; |
| 123 | struct semaphore dead_sem; |
| 124 | spinlock_t lock; |
| 125 | }; |
| 126 | |
| 127 | #define AX25_6PACK_HEADER_LEN 0 |
| 128 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | static void sixpack_decode(struct sixpack *, unsigned char[], int); |
| 130 | static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); |
| 131 | |
| 132 | /* |
Ralf Baechle DL5RB | c043817 | 2005-08-10 10:03:20 -0700 | [diff] [blame] | 133 | * Perform the persistence/slottime algorithm for CSMA access. If the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | * persistence check was successful, write the data to the serial driver. |
| 135 | * Note that in case of DAMA operation, the data is not sent here. |
| 136 | */ |
| 137 | |
| 138 | static void sp_xmit_on_air(unsigned long channel) |
| 139 | { |
| 140 | struct sixpack *sp = (struct sixpack *) channel; |
Ralf Baechle DL5RB | c043817 | 2005-08-10 10:03:20 -0700 | [diff] [blame] | 141 | int actual, when = sp->slottime; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | static unsigned char random; |
| 143 | |
| 144 | random = random * 17 + 41; |
| 145 | |
| 146 | if (((sp->status1 & SIXP_DCD_MASK) == 0) && (random < sp->persistence)) { |
| 147 | sp->led_state = 0x70; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 148 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | sp->tx_enable = 1; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 150 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | sp->xleft -= actual; |
| 152 | sp->xhead += actual; |
| 153 | sp->led_state = 0x60; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 154 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | sp->status2 = 0; |
| 156 | } else |
Ralf Baechle DL5RB | c043817 | 2005-08-10 10:03:20 -0700 | [diff] [blame] | 157 | mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | } |
| 159 | |
| 160 | /* ----> 6pack timer interrupt handler and friends. <---- */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
| 162 | /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ |
| 163 | static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) |
| 164 | { |
| 165 | unsigned char *msg, *p = icp; |
| 166 | int actual, count; |
| 167 | |
| 168 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ |
| 169 | msg = "oversized transmit packet!"; |
| 170 | goto out_drop; |
| 171 | } |
| 172 | |
| 173 | if (len > sp->mtu) { /* sp->mtu = AX25_MTU = max. PACLEN = 256 */ |
| 174 | msg = "oversized transmit packet!"; |
| 175 | goto out_drop; |
| 176 | } |
| 177 | |
| 178 | if (p[0] > 5) { |
| 179 | msg = "invalid KISS command"; |
| 180 | goto out_drop; |
| 181 | } |
| 182 | |
| 183 | if ((p[0] != 0) && (len > 2)) { |
| 184 | msg = "KISS control packet too long"; |
| 185 | goto out_drop; |
| 186 | } |
| 187 | |
| 188 | if ((p[0] == 0) && (len < 15)) { |
| 189 | msg = "bad AX.25 packet to transmit"; |
| 190 | goto out_drop; |
| 191 | } |
| 192 | |
| 193 | count = encode_sixpack(p, sp->xbuff, len, sp->tx_delay); |
| 194 | set_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); |
| 195 | |
| 196 | switch (p[0]) { |
| 197 | case 1: sp->tx_delay = p[1]; |
| 198 | return; |
| 199 | case 2: sp->persistence = p[1]; |
| 200 | return; |
| 201 | case 3: sp->slottime = p[1]; |
| 202 | return; |
| 203 | case 4: /* ignored */ |
| 204 | return; |
| 205 | case 5: sp->duplex = p[1]; |
| 206 | return; |
| 207 | } |
| 208 | |
| 209 | if (p[0] != 0) |
| 210 | return; |
| 211 | |
| 212 | /* |
| 213 | * In case of fullduplex or DAMA operation, we don't take care about the |
| 214 | * state of the DCD or of any timers, as the determination of the |
| 215 | * correct time to send is the job of the AX.25 layer. We send |
| 216 | * immediately after data has arrived. |
| 217 | */ |
| 218 | if (sp->duplex == 1) { |
| 219 | sp->led_state = 0x70; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 220 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | sp->tx_enable = 1; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 222 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, count); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | sp->xleft = count - actual; |
| 224 | sp->xhead = sp->xbuff + actual; |
| 225 | sp->led_state = 0x60; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 226 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | } else { |
| 228 | sp->xleft = count; |
| 229 | sp->xhead = sp->xbuff; |
| 230 | sp->status2 = count; |
Ralf Baechle DL5RB | c043817 | 2005-08-10 10:03:20 -0700 | [diff] [blame] | 231 | sp_xmit_on_air((unsigned long)sp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | } |
| 233 | |
| 234 | return; |
| 235 | |
| 236 | out_drop: |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 237 | sp->dev->stats.tx_dropped++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | netif_start_queue(sp->dev); |
| 239 | if (net_ratelimit()) |
| 240 | printk(KERN_DEBUG "%s: %s - dropped.\n", sp->dev->name, msg); |
| 241 | } |
| 242 | |
| 243 | /* Encapsulate an IP datagram and kick it into a TTY queue. */ |
| 244 | |
| 245 | static int sp_xmit(struct sk_buff *skb, struct net_device *dev) |
| 246 | { |
| 247 | struct sixpack *sp = netdev_priv(dev); |
| 248 | |
| 249 | spin_lock_bh(&sp->lock); |
| 250 | /* We were not busy, so we are now... :-) */ |
| 251 | netif_stop_queue(dev); |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 252 | dev->stats.tx_bytes += skb->len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 253 | sp_encaps(sp, skb->data, skb->len); |
| 254 | spin_unlock_bh(&sp->lock); |
| 255 | |
| 256 | dev_kfree_skb(skb); |
| 257 | |
| 258 | return 0; |
| 259 | } |
| 260 | |
| 261 | static int sp_open_dev(struct net_device *dev) |
| 262 | { |
| 263 | struct sixpack *sp = netdev_priv(dev); |
| 264 | |
| 265 | if (sp->tty == NULL) |
| 266 | return -ENODEV; |
| 267 | return 0; |
| 268 | } |
| 269 | |
| 270 | /* Close the low-level part of the 6pack channel. */ |
| 271 | static int sp_close(struct net_device *dev) |
| 272 | { |
| 273 | struct sixpack *sp = netdev_priv(dev); |
| 274 | |
| 275 | spin_lock_bh(&sp->lock); |
| 276 | if (sp->tty) { |
| 277 | /* TTY discipline is running. */ |
| 278 | clear_bit(TTY_DO_WRITE_WAKEUP, &sp->tty->flags); |
| 279 | } |
| 280 | netif_stop_queue(dev); |
| 281 | spin_unlock_bh(&sp->lock); |
| 282 | |
| 283 | return 0; |
| 284 | } |
| 285 | |
| 286 | /* Return the frame type ID */ |
| 287 | static int sp_header(struct sk_buff *skb, struct net_device *dev, |
Stephen Hemminger | 3b04ddd | 2007-10-09 01:40:57 -0700 | [diff] [blame] | 288 | unsigned short type, const void *daddr, |
| 289 | const void *saddr, unsigned len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | { |
| 291 | #ifdef CONFIG_INET |
Al Viro | d9a19d2 | 2007-10-14 19:40:49 +0100 | [diff] [blame] | 292 | if (type != ETH_P_AX25) |
Ralf Baechle | 6f74998 | 2005-09-12 14:21:01 -0700 | [diff] [blame] | 293 | return ax25_hard_header(skb, dev, type, daddr, saddr, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 294 | #endif |
| 295 | return 0; |
| 296 | } |
| 297 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | static int sp_set_mac_address(struct net_device *dev, void *addr) |
| 299 | { |
| 300 | struct sockaddr_ax25 *sa = addr; |
| 301 | |
Herbert Xu | 932ff27 | 2006-06-09 12:20:56 -0700 | [diff] [blame] | 302 | netif_tx_lock_bh(dev); |
David S. Miller | e308a5d | 2008-07-15 00:13:44 -0700 | [diff] [blame] | 303 | netif_addr_lock(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | memcpy(dev->dev_addr, &sa->sax25_call, AX25_ADDR_LEN); |
David S. Miller | e308a5d | 2008-07-15 00:13:44 -0700 | [diff] [blame] | 305 | netif_addr_unlock(dev); |
Herbert Xu | 932ff27 | 2006-06-09 12:20:56 -0700 | [diff] [blame] | 306 | netif_tx_unlock_bh(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | |
| 308 | return 0; |
| 309 | } |
| 310 | |
| 311 | static int sp_rebuild_header(struct sk_buff *skb) |
| 312 | { |
| 313 | #ifdef CONFIG_INET |
| 314 | return ax25_rebuild_header(skb); |
| 315 | #else |
| 316 | return 0; |
| 317 | #endif |
| 318 | } |
| 319 | |
Stephen Hemminger | 3b04ddd | 2007-10-09 01:40:57 -0700 | [diff] [blame] | 320 | static const struct header_ops sp_header_ops = { |
| 321 | .create = sp_header, |
| 322 | .rebuild = sp_rebuild_header, |
| 323 | }; |
| 324 | |
Stephen Hemminger | b3672a7 | 2009-01-09 13:01:28 +0000 | [diff] [blame] | 325 | static const struct net_device_ops sp_netdev_ops = { |
| 326 | .ndo_open = sp_open_dev, |
| 327 | .ndo_stop = sp_close, |
| 328 | .ndo_start_xmit = sp_xmit, |
| 329 | .ndo_set_mac_address = sp_set_mac_address, |
| 330 | }; |
| 331 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 332 | static void sp_setup(struct net_device *dev) |
| 333 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | /* Finish setting up the DEVICE info. */ |
Stephen Hemminger | b3672a7 | 2009-01-09 13:01:28 +0000 | [diff] [blame] | 335 | dev->netdev_ops = &sp_netdev_ops; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | dev->destructor = free_netdev; |
Stephen Hemminger | b3672a7 | 2009-01-09 13:01:28 +0000 | [diff] [blame] | 337 | dev->mtu = SIXP_MTU; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | dev->hard_header_len = AX25_MAX_HEADER_LEN; |
Stephen Hemminger | 3b04ddd | 2007-10-09 01:40:57 -0700 | [diff] [blame] | 339 | dev->header_ops = &sp_header_ops; |
| 340 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | dev->addr_len = AX25_ADDR_LEN; |
| 342 | dev->type = ARPHRD_AX25; |
| 343 | dev->tx_queue_len = 10; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | |
| 345 | /* Only activated in AX.25 mode */ |
Ralf Baechle | 15b1c0e | 2006-12-07 15:47:08 -0800 | [diff] [blame] | 346 | memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN); |
| 347 | memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | dev->flags = 0; |
| 350 | } |
| 351 | |
| 352 | /* Send one completely decapsulated IP datagram to the IP layer. */ |
| 353 | |
| 354 | /* |
| 355 | * This is the routine that sends the received data to the kernel AX.25. |
| 356 | * 'cmd' is the KISS command. For AX.25 data, it is zero. |
| 357 | */ |
| 358 | |
| 359 | static void sp_bump(struct sixpack *sp, char cmd) |
| 360 | { |
| 361 | struct sk_buff *skb; |
| 362 | int count; |
| 363 | unsigned char *ptr; |
| 364 | |
| 365 | count = sp->rcount + 1; |
| 366 | |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 367 | sp->dev->stats.rx_bytes += count; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 368 | |
| 369 | if ((skb = dev_alloc_skb(count)) == NULL) |
| 370 | goto out_mem; |
| 371 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 372 | ptr = skb_put(skb, count); |
| 373 | *ptr++ = cmd; /* KISS command */ |
| 374 | |
| 375 | memcpy(ptr, sp->cooked_buf + 1, count); |
Arnaldo Carvalho de Melo | 56cb515 | 2005-04-24 18:53:06 -0700 | [diff] [blame] | 376 | skb->protocol = ax25_type_trans(skb, sp->dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 377 | netif_rx(skb); |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 378 | sp->dev->stats.rx_packets++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | |
| 380 | return; |
| 381 | |
| 382 | out_mem: |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 383 | sp->dev->stats.rx_dropped++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | } |
| 385 | |
| 386 | |
| 387 | /* ----------------------------------------------------------------------- */ |
| 388 | |
| 389 | /* |
| 390 | * We have a potential race on dereferencing tty->disc_data, because the tty |
| 391 | * layer provides no locking at all - thus one cpu could be running |
| 392 | * sixpack_receive_buf while another calls sixpack_close, which zeroes |
| 393 | * tty->disc_data and frees the memory that sixpack_receive_buf is using. The |
| 394 | * best way to fix this is to use a rwlock in the tty struct, but for now we |
| 395 | * use a single global rwlock for all ttys in ppp line discipline. |
| 396 | */ |
| 397 | static DEFINE_RWLOCK(disc_data_lock); |
| 398 | |
| 399 | static struct sixpack *sp_get(struct tty_struct *tty) |
| 400 | { |
| 401 | struct sixpack *sp; |
| 402 | |
| 403 | read_lock(&disc_data_lock); |
| 404 | sp = tty->disc_data; |
| 405 | if (sp) |
| 406 | atomic_inc(&sp->refcnt); |
| 407 | read_unlock(&disc_data_lock); |
| 408 | |
| 409 | return sp; |
| 410 | } |
| 411 | |
| 412 | static void sp_put(struct sixpack *sp) |
| 413 | { |
| 414 | if (atomic_dec_and_test(&sp->refcnt)) |
| 415 | up(&sp->dead_sem); |
| 416 | } |
| 417 | |
| 418 | /* |
| 419 | * Called by the TTY driver when there's room for more data. If we have |
| 420 | * more packets to send, we send them here. |
| 421 | */ |
| 422 | static void sixpack_write_wakeup(struct tty_struct *tty) |
| 423 | { |
| 424 | struct sixpack *sp = sp_get(tty); |
| 425 | int actual; |
| 426 | |
| 427 | if (!sp) |
| 428 | return; |
| 429 | if (sp->xleft <= 0) { |
| 430 | /* Now serial buffer is almost free & we can start |
| 431 | * transmission of another packet */ |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 432 | sp->dev->stats.tx_packets++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
| 434 | sp->tx_enable = 0; |
| 435 | netif_wake_queue(sp->dev); |
| 436 | goto out; |
| 437 | } |
| 438 | |
| 439 | if (sp->tx_enable) { |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 440 | actual = tty->ops->write(tty, sp->xhead, sp->xleft); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | sp->xleft -= actual; |
| 442 | sp->xhead += actual; |
| 443 | } |
| 444 | |
| 445 | out: |
| 446 | sp_put(sp); |
| 447 | } |
| 448 | |
| 449 | /* ----------------------------------------------------------------------- */ |
| 450 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 451 | /* |
| 452 | * Handle the 'receiver data ready' interrupt. |
| 453 | * This function is called by the 'tty_io' module in the kernel when |
| 454 | * a block of 6pack data has been received, which can now be decapsulated |
| 455 | * and sent on to some IP layer for further processing. |
| 456 | */ |
| 457 | static void sixpack_receive_buf(struct tty_struct *tty, |
| 458 | const unsigned char *cp, char *fp, int count) |
| 459 | { |
| 460 | struct sixpack *sp; |
| 461 | unsigned char buf[512]; |
| 462 | int count1; |
| 463 | |
| 464 | if (!count) |
| 465 | return; |
| 466 | |
| 467 | sp = sp_get(tty); |
| 468 | if (!sp) |
| 469 | return; |
| 470 | |
| 471 | memcpy(buf, cp, count < sizeof(buf) ? count : sizeof(buf)); |
| 472 | |
| 473 | /* Read the characters out of the buffer */ |
| 474 | |
| 475 | count1 = count; |
| 476 | while (count) { |
| 477 | count--; |
| 478 | if (fp && *fp++) { |
| 479 | if (!test_and_set_bit(SIXPF_ERROR, &sp->flags)) |
Paulius Zaleckas | de0561c | 2008-04-30 01:49:15 +0300 | [diff] [blame] | 480 | sp->dev->stats.rx_errors++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | continue; |
| 482 | } |
| 483 | } |
| 484 | sixpack_decode(sp, buf, count1); |
| 485 | |
| 486 | sp_put(sp); |
Alan Cox | 39c2e60 | 2008-04-30 00:54:18 -0700 | [diff] [blame] | 487 | tty_unthrottle(tty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | } |
| 489 | |
| 490 | /* |
| 491 | * Try to resync the TNC. Called by the resync timer defined in |
| 492 | * decode_prio_command |
| 493 | */ |
| 494 | |
| 495 | #define TNC_UNINITIALIZED 0 |
| 496 | #define TNC_UNSYNC_STARTUP 1 |
| 497 | #define TNC_UNSYNCED 2 |
| 498 | #define TNC_IN_SYNC 3 |
| 499 | |
| 500 | static void __tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) |
| 501 | { |
| 502 | char *msg; |
| 503 | |
| 504 | switch (new_tnc_state) { |
| 505 | default: /* gcc oh piece-o-crap ... */ |
| 506 | case TNC_UNSYNC_STARTUP: |
| 507 | msg = "Synchronizing with TNC"; |
| 508 | break; |
| 509 | case TNC_UNSYNCED: |
| 510 | msg = "Lost synchronization with TNC\n"; |
| 511 | break; |
| 512 | case TNC_IN_SYNC: |
| 513 | msg = "Found TNC"; |
| 514 | break; |
| 515 | } |
| 516 | |
| 517 | sp->tnc_state = new_tnc_state; |
| 518 | printk(KERN_INFO "%s: %s\n", sp->dev->name, msg); |
| 519 | } |
| 520 | |
| 521 | static inline void tnc_set_sync_state(struct sixpack *sp, int new_tnc_state) |
| 522 | { |
| 523 | int old_tnc_state = sp->tnc_state; |
| 524 | |
| 525 | if (old_tnc_state != new_tnc_state) |
| 526 | __tnc_set_sync_state(sp, new_tnc_state); |
| 527 | } |
| 528 | |
| 529 | static void resync_tnc(unsigned long channel) |
| 530 | { |
| 531 | struct sixpack *sp = (struct sixpack *) channel; |
| 532 | static char resync_cmd = 0xe8; |
| 533 | |
| 534 | /* clear any data that might have been received */ |
| 535 | |
| 536 | sp->rx_count = 0; |
| 537 | sp->rx_count_cooked = 0; |
| 538 | |
| 539 | /* reset state machine */ |
| 540 | |
| 541 | sp->status = 1; |
| 542 | sp->status1 = 1; |
| 543 | sp->status2 = 0; |
| 544 | |
| 545 | /* resync the TNC */ |
| 546 | |
| 547 | sp->led_state = 0x60; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 548 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
| 549 | sp->tty->ops->write(sp->tty, &resync_cmd, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 550 | |
| 551 | |
| 552 | /* Start resync timer again -- the TNC might be still absent */ |
| 553 | |
| 554 | del_timer(&sp->resync_t); |
| 555 | sp->resync_t.data = (unsigned long) sp; |
| 556 | sp->resync_t.function = resync_tnc; |
| 557 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; |
| 558 | add_timer(&sp->resync_t); |
| 559 | } |
| 560 | |
| 561 | static inline int tnc_init(struct sixpack *sp) |
| 562 | { |
| 563 | unsigned char inbyte = 0xe8; |
| 564 | |
| 565 | tnc_set_sync_state(sp, TNC_UNSYNC_STARTUP); |
| 566 | |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 567 | sp->tty->ops->write(sp->tty, &inbyte, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 568 | |
| 569 | del_timer(&sp->resync_t); |
| 570 | sp->resync_t.data = (unsigned long) sp; |
| 571 | sp->resync_t.function = resync_tnc; |
| 572 | sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT; |
| 573 | add_timer(&sp->resync_t); |
| 574 | |
| 575 | return 0; |
| 576 | } |
| 577 | |
| 578 | /* |
| 579 | * Open the high-level part of the 6pack channel. |
| 580 | * This function is called by the TTY module when the |
| 581 | * 6pack line discipline is called for. Because we are |
| 582 | * sure the tty line exists, we only have to link it to |
| 583 | * a free 6pcack channel... |
| 584 | */ |
| 585 | static int sixpack_open(struct tty_struct *tty) |
| 586 | { |
| 587 | char *rbuff = NULL, *xbuff = NULL; |
| 588 | struct net_device *dev; |
| 589 | struct sixpack *sp; |
| 590 | unsigned long len; |
| 591 | int err = 0; |
| 592 | |
| 593 | if (!capable(CAP_NET_ADMIN)) |
| 594 | return -EPERM; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 595 | if (tty->ops->write == NULL) |
| 596 | return -EOPNOTSUPP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | |
| 598 | dev = alloc_netdev(sizeof(struct sixpack), "sp%d", sp_setup); |
| 599 | if (!dev) { |
| 600 | err = -ENOMEM; |
| 601 | goto out; |
| 602 | } |
| 603 | |
| 604 | sp = netdev_priv(dev); |
| 605 | sp->dev = dev; |
| 606 | |
| 607 | spin_lock_init(&sp->lock); |
| 608 | atomic_set(&sp->refcnt, 1); |
| 609 | init_MUTEX_LOCKED(&sp->dead_sem); |
| 610 | |
| 611 | /* !!! length of the buffers. MTU is IP MTU, not PACLEN! */ |
| 612 | |
| 613 | len = dev->mtu * 2; |
| 614 | |
| 615 | rbuff = kmalloc(len + 4, GFP_KERNEL); |
| 616 | xbuff = kmalloc(len + 4, GFP_KERNEL); |
| 617 | |
| 618 | if (rbuff == NULL || xbuff == NULL) { |
| 619 | err = -ENOBUFS; |
| 620 | goto out_free; |
| 621 | } |
| 622 | |
| 623 | spin_lock_bh(&sp->lock); |
| 624 | |
| 625 | sp->tty = tty; |
| 626 | |
| 627 | sp->rbuff = rbuff; |
| 628 | sp->xbuff = xbuff; |
| 629 | |
| 630 | sp->mtu = AX25_MTU + 73; |
| 631 | sp->buffsize = len; |
| 632 | sp->rcount = 0; |
| 633 | sp->rx_count = 0; |
| 634 | sp->rx_count_cooked = 0; |
| 635 | sp->xleft = 0; |
| 636 | |
| 637 | sp->flags = 0; /* Clear ESCAPE & ERROR flags */ |
| 638 | |
| 639 | sp->duplex = 0; |
| 640 | sp->tx_delay = SIXP_TXDELAY; |
| 641 | sp->persistence = SIXP_PERSIST; |
| 642 | sp->slottime = SIXP_SLOTTIME; |
| 643 | sp->led_state = 0x60; |
| 644 | sp->status = 1; |
| 645 | sp->status1 = 1; |
| 646 | sp->status2 = 0; |
| 647 | sp->tx_enable = 0; |
| 648 | |
| 649 | netif_start_queue(dev); |
| 650 | |
| 651 | init_timer(&sp->tx_t); |
Ralf Baechle | 84a2ea1 | 2005-08-25 19:38:30 +0100 | [diff] [blame] | 652 | sp->tx_t.function = sp_xmit_on_air; |
| 653 | sp->tx_t.data = (unsigned long) sp; |
| 654 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | init_timer(&sp->resync_t); |
| 656 | |
| 657 | spin_unlock_bh(&sp->lock); |
| 658 | |
| 659 | /* Done. We have linked the TTY line to a channel. */ |
| 660 | tty->disc_data = sp; |
Alan Cox | 33f0f88 | 2006-01-09 20:54:13 -0800 | [diff] [blame] | 661 | tty->receive_room = 65536; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | |
| 663 | /* Now we're ready to register. */ |
| 664 | if (register_netdev(dev)) |
| 665 | goto out_free; |
| 666 | |
| 667 | tnc_init(sp); |
| 668 | |
| 669 | return 0; |
| 670 | |
| 671 | out_free: |
| 672 | kfree(xbuff); |
| 673 | kfree(rbuff); |
| 674 | |
| 675 | if (dev) |
| 676 | free_netdev(dev); |
| 677 | |
| 678 | out: |
| 679 | return err; |
| 680 | } |
| 681 | |
| 682 | |
| 683 | /* |
| 684 | * Close down a 6pack channel. |
| 685 | * This means flushing out any pending queues, and then restoring the |
| 686 | * TTY line discipline to what it was before it got hooked to 6pack |
| 687 | * (which usually is TTY again). |
| 688 | */ |
| 689 | static void sixpack_close(struct tty_struct *tty) |
| 690 | { |
| 691 | struct sixpack *sp; |
| 692 | |
| 693 | write_lock(&disc_data_lock); |
| 694 | sp = tty->disc_data; |
| 695 | tty->disc_data = NULL; |
| 696 | write_unlock(&disc_data_lock); |
Al Viro | 79ea13c | 2008-01-24 02:06:46 -0800 | [diff] [blame] | 697 | if (!sp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 698 | return; |
| 699 | |
| 700 | /* |
| 701 | * We have now ensured that nobody can start using ap from now on, but |
| 702 | * we have to wait for all existing users to finish. |
| 703 | */ |
| 704 | if (!atomic_dec_and_test(&sp->refcnt)) |
| 705 | down(&sp->dead_sem); |
| 706 | |
| 707 | unregister_netdev(sp->dev); |
| 708 | |
| 709 | del_timer(&sp->tx_t); |
| 710 | del_timer(&sp->resync_t); |
| 711 | |
| 712 | /* Free all 6pack frame buffers. */ |
| 713 | kfree(sp->rbuff); |
| 714 | kfree(sp->xbuff); |
| 715 | } |
| 716 | |
| 717 | /* Perform I/O control on an active 6pack channel. */ |
| 718 | static int sixpack_ioctl(struct tty_struct *tty, struct file *file, |
| 719 | unsigned int cmd, unsigned long arg) |
| 720 | { |
| 721 | struct sixpack *sp = sp_get(tty); |
Julia Lawall | 0397a26 | 2009-01-09 10:23:09 +0000 | [diff] [blame] | 722 | struct net_device *dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 723 | unsigned int tmp, err; |
| 724 | |
| 725 | if (!sp) |
| 726 | return -ENXIO; |
Julia Lawall | 0397a26 | 2009-01-09 10:23:09 +0000 | [diff] [blame] | 727 | dev = sp->dev; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | |
| 729 | switch(cmd) { |
| 730 | case SIOCGIFNAME: |
| 731 | err = copy_to_user((void __user *) arg, dev->name, |
| 732 | strlen(dev->name) + 1) ? -EFAULT : 0; |
| 733 | break; |
| 734 | |
| 735 | case SIOCGIFENCAP: |
| 736 | err = put_user(0, (int __user *) arg); |
| 737 | break; |
| 738 | |
| 739 | case SIOCSIFENCAP: |
| 740 | if (get_user(tmp, (int __user *) arg)) { |
| 741 | err = -EFAULT; |
| 742 | break; |
| 743 | } |
| 744 | |
| 745 | sp->mode = tmp; |
| 746 | dev->addr_len = AX25_ADDR_LEN; |
| 747 | dev->hard_header_len = AX25_KISS_HEADER_LEN + |
| 748 | AX25_MAX_HEADER_LEN + 3; |
| 749 | dev->type = ARPHRD_AX25; |
| 750 | |
| 751 | err = 0; |
| 752 | break; |
| 753 | |
| 754 | case SIOCSIFHWADDR: { |
| 755 | char addr[AX25_ADDR_LEN]; |
| 756 | |
| 757 | if (copy_from_user(&addr, |
| 758 | (void __user *) arg, AX25_ADDR_LEN)) { |
Alan Cox | d012753 | 2007-11-07 01:27:34 -0800 | [diff] [blame] | 759 | err = -EFAULT; |
| 760 | break; |
| 761 | } |
| 762 | |
| 763 | netif_tx_lock_bh(dev); |
| 764 | memcpy(dev->dev_addr, &addr, AX25_ADDR_LEN); |
| 765 | netif_tx_unlock_bh(dev); |
| 766 | |
| 767 | err = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | break; |
| 769 | } |
| 770 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 771 | default: |
Alan Cox | d012753 | 2007-11-07 01:27:34 -0800 | [diff] [blame] | 772 | err = tty_mode_ioctl(tty, file, cmd, arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 773 | } |
| 774 | |
| 775 | sp_put(sp); |
| 776 | |
| 777 | return err; |
| 778 | } |
| 779 | |
Alan Cox | a352def | 2008-07-16 21:53:12 +0100 | [diff] [blame] | 780 | static struct tty_ldisc_ops sp_ldisc = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | .owner = THIS_MODULE, |
| 782 | .magic = TTY_LDISC_MAGIC, |
| 783 | .name = "6pack", |
| 784 | .open = sixpack_open, |
| 785 | .close = sixpack_close, |
| 786 | .ioctl = sixpack_ioctl, |
| 787 | .receive_buf = sixpack_receive_buf, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 788 | .write_wakeup = sixpack_write_wakeup, |
| 789 | }; |
| 790 | |
| 791 | /* Initialize 6pack control device -- register 6pack line discipline */ |
| 792 | |
Hannes Eder | eb33ae2 | 2009-02-14 11:33:21 +0000 | [diff] [blame] | 793 | static const char msg_banner[] __initdata = KERN_INFO \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 794 | "AX.25: 6pack driver, " SIXPACK_VERSION "\n"; |
Hannes Eder | eb33ae2 | 2009-02-14 11:33:21 +0000 | [diff] [blame] | 795 | static const char msg_regfail[] __initdata = KERN_ERR \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 796 | "6pack: can't register line discipline (err = %d)\n"; |
| 797 | |
| 798 | static int __init sixpack_init_driver(void) |
| 799 | { |
| 800 | int status; |
| 801 | |
| 802 | printk(msg_banner); |
| 803 | |
| 804 | /* Register the provided line protocol discipline */ |
| 805 | if ((status = tty_register_ldisc(N_6PACK, &sp_ldisc)) != 0) |
| 806 | printk(msg_regfail, status); |
| 807 | |
| 808 | return status; |
| 809 | } |
| 810 | |
| 811 | static const char msg_unregfail[] __exitdata = KERN_ERR \ |
| 812 | "6pack: can't unregister line discipline (err = %d)\n"; |
| 813 | |
| 814 | static void __exit sixpack_exit_driver(void) |
| 815 | { |
| 816 | int ret; |
| 817 | |
Alexey Dobriyan | 64ccd71 | 2005-06-23 00:10:33 -0700 | [diff] [blame] | 818 | if ((ret = tty_unregister_ldisc(N_6PACK))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 819 | printk(msg_unregfail, ret); |
| 820 | } |
| 821 | |
| 822 | /* encode an AX.25 packet into 6pack */ |
| 823 | |
| 824 | static int encode_sixpack(unsigned char *tx_buf, unsigned char *tx_buf_raw, |
| 825 | int length, unsigned char tx_delay) |
| 826 | { |
| 827 | int count = 0; |
| 828 | unsigned char checksum = 0, buf[400]; |
| 829 | int raw_count = 0; |
| 830 | |
| 831 | tx_buf_raw[raw_count++] = SIXP_PRIO_CMD_MASK | SIXP_TX_MASK; |
| 832 | tx_buf_raw[raw_count++] = SIXP_SEOF; |
| 833 | |
| 834 | buf[0] = tx_delay; |
| 835 | for (count = 1; count < length; count++) |
| 836 | buf[count] = tx_buf[count]; |
| 837 | |
| 838 | for (count = 0; count < length; count++) |
| 839 | checksum += buf[count]; |
| 840 | buf[length] = (unsigned char) 0xff - checksum; |
| 841 | |
| 842 | for (count = 0; count <= length; count++) { |
| 843 | if ((count % 3) == 0) { |
| 844 | tx_buf_raw[raw_count++] = (buf[count] & 0x3f); |
| 845 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x30); |
| 846 | } else if ((count % 3) == 1) { |
| 847 | tx_buf_raw[raw_count++] |= (buf[count] & 0x0f); |
| 848 | tx_buf_raw[raw_count] = ((buf[count] >> 2) & 0x3c); |
| 849 | } else { |
| 850 | tx_buf_raw[raw_count++] |= (buf[count] & 0x03); |
| 851 | tx_buf_raw[raw_count++] = (buf[count] >> 2); |
| 852 | } |
| 853 | } |
| 854 | if ((length % 3) != 2) |
| 855 | raw_count++; |
| 856 | tx_buf_raw[raw_count++] = SIXP_SEOF; |
| 857 | return raw_count; |
| 858 | } |
| 859 | |
| 860 | /* decode 4 sixpack-encoded bytes into 3 data bytes */ |
| 861 | |
| 862 | static void decode_data(struct sixpack *sp, unsigned char inbyte) |
| 863 | { |
| 864 | unsigned char *buf; |
| 865 | |
| 866 | if (sp->rx_count != 3) { |
| 867 | sp->raw_buf[sp->rx_count++] = inbyte; |
| 868 | |
| 869 | return; |
| 870 | } |
| 871 | |
| 872 | buf = sp->raw_buf; |
| 873 | sp->cooked_buf[sp->rx_count_cooked++] = |
| 874 | buf[0] | ((buf[1] << 2) & 0xc0); |
| 875 | sp->cooked_buf[sp->rx_count_cooked++] = |
| 876 | (buf[1] & 0x0f) | ((buf[2] << 2) & 0xf0); |
| 877 | sp->cooked_buf[sp->rx_count_cooked++] = |
| 878 | (buf[2] & 0x03) | (inbyte << 2); |
| 879 | sp->rx_count = 0; |
| 880 | } |
| 881 | |
| 882 | /* identify and execute a 6pack priority command byte */ |
| 883 | |
| 884 | static void decode_prio_command(struct sixpack *sp, unsigned char cmd) |
| 885 | { |
| 886 | unsigned char channel; |
| 887 | int actual; |
| 888 | |
| 889 | channel = cmd & SIXP_CHN_MASK; |
| 890 | if ((cmd & SIXP_PRIO_DATA_MASK) != 0) { /* idle ? */ |
| 891 | |
| 892 | /* RX and DCD flags can only be set in the same prio command, |
| 893 | if the DCD flag has been set without the RX flag in the previous |
| 894 | prio command. If DCD has not been set before, something in the |
| 895 | transmission has gone wrong. In this case, RX and DCD are |
| 896 | cleared in order to prevent the decode_data routine from |
| 897 | reading further data that might be corrupt. */ |
| 898 | |
| 899 | if (((sp->status & SIXP_DCD_MASK) == 0) && |
| 900 | ((cmd & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK)) { |
| 901 | if (sp->status != 1) |
| 902 | printk(KERN_DEBUG "6pack: protocol violation\n"); |
| 903 | else |
| 904 | sp->status = 0; |
Jean Delvare | 95f6134 | 2006-11-23 11:48:28 -0800 | [diff] [blame] | 905 | cmd &= ~SIXP_RX_DCD_MASK; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | } |
| 907 | sp->status = cmd & SIXP_PRIO_DATA_MASK; |
| 908 | } else { /* output watchdog char if idle */ |
| 909 | if ((sp->status2 != 0) && (sp->duplex == 1)) { |
| 910 | sp->led_state = 0x70; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 911 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | sp->tx_enable = 1; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 913 | actual = sp->tty->ops->write(sp->tty, sp->xbuff, sp->status2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 914 | sp->xleft -= actual; |
| 915 | sp->xhead += actual; |
| 916 | sp->led_state = 0x60; |
| 917 | sp->status2 = 0; |
| 918 | |
| 919 | } |
| 920 | } |
| 921 | |
| 922 | /* needed to trigger the TNC watchdog */ |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 923 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 924 | |
| 925 | /* if the state byte has been received, the TNC is present, |
| 926 | so the resync timer can be reset. */ |
| 927 | |
| 928 | if (sp->tnc_state == TNC_IN_SYNC) { |
| 929 | del_timer(&sp->resync_t); |
| 930 | sp->resync_t.data = (unsigned long) sp; |
| 931 | sp->resync_t.function = resync_tnc; |
| 932 | sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT; |
| 933 | add_timer(&sp->resync_t); |
| 934 | } |
| 935 | |
| 936 | sp->status1 = cmd & SIXP_PRIO_DATA_MASK; |
| 937 | } |
| 938 | |
| 939 | /* identify and execute a standard 6pack command byte */ |
| 940 | |
| 941 | static void decode_std_command(struct sixpack *sp, unsigned char cmd) |
| 942 | { |
| 943 | unsigned char checksum = 0, rest = 0, channel; |
| 944 | short i; |
| 945 | |
| 946 | channel = cmd & SIXP_CHN_MASK; |
| 947 | switch (cmd & SIXP_CMD_MASK) { /* normal command */ |
| 948 | case SIXP_SEOF: |
| 949 | if ((sp->rx_count == 0) && (sp->rx_count_cooked == 0)) { |
| 950 | if ((sp->status & SIXP_RX_DCD_MASK) == |
| 951 | SIXP_RX_DCD_MASK) { |
| 952 | sp->led_state = 0x68; |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 953 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 954 | } |
| 955 | } else { |
| 956 | sp->led_state = 0x60; |
| 957 | /* fill trailing bytes with zeroes */ |
Alan Cox | f34d7a5 | 2008-04-30 00:54:13 -0700 | [diff] [blame] | 958 | sp->tty->ops->write(sp->tty, &sp->led_state, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 959 | rest = sp->rx_count; |
| 960 | if (rest != 0) |
| 961 | for (i = rest; i <= 3; i++) |
| 962 | decode_data(sp, 0); |
| 963 | if (rest == 2) |
| 964 | sp->rx_count_cooked -= 2; |
| 965 | else if (rest == 3) |
| 966 | sp->rx_count_cooked -= 1; |
| 967 | for (i = 0; i < sp->rx_count_cooked; i++) |
| 968 | checksum += sp->cooked_buf[i]; |
| 969 | if (checksum != SIXP_CHKSUM) { |
| 970 | printk(KERN_DEBUG "6pack: bad checksum %2.2x\n", checksum); |
| 971 | } else { |
| 972 | sp->rcount = sp->rx_count_cooked-2; |
| 973 | sp_bump(sp, 0); |
| 974 | } |
| 975 | sp->rx_count_cooked = 0; |
| 976 | } |
| 977 | break; |
| 978 | case SIXP_TX_URUN: printk(KERN_DEBUG "6pack: TX underrun\n"); |
| 979 | break; |
| 980 | case SIXP_RX_ORUN: printk(KERN_DEBUG "6pack: RX overrun\n"); |
| 981 | break; |
| 982 | case SIXP_RX_BUF_OVL: |
| 983 | printk(KERN_DEBUG "6pack: RX buffer overflow\n"); |
| 984 | } |
| 985 | } |
| 986 | |
| 987 | /* decode a 6pack packet */ |
| 988 | |
| 989 | static void |
| 990 | sixpack_decode(struct sixpack *sp, unsigned char *pre_rbuff, int count) |
| 991 | { |
| 992 | unsigned char inbyte; |
| 993 | int count1; |
| 994 | |
| 995 | for (count1 = 0; count1 < count; count1++) { |
| 996 | inbyte = pre_rbuff[count1]; |
| 997 | if (inbyte == SIXP_FOUND_TNC) { |
| 998 | tnc_set_sync_state(sp, TNC_IN_SYNC); |
| 999 | del_timer(&sp->resync_t); |
| 1000 | } |
| 1001 | if ((inbyte & SIXP_PRIO_CMD_MASK) != 0) |
| 1002 | decode_prio_command(sp, inbyte); |
| 1003 | else if ((inbyte & SIXP_STD_CMD_MASK) != 0) |
| 1004 | decode_std_command(sp, inbyte); |
| 1005 | else if ((sp->status & SIXP_RX_DCD_MASK) == SIXP_RX_DCD_MASK) |
| 1006 | decode_data(sp, inbyte); |
| 1007 | } |
| 1008 | } |
| 1009 | |
| 1010 | MODULE_AUTHOR("Ralf Baechle DO1GRB <ralf@linux-mips.org>"); |
| 1011 | MODULE_DESCRIPTION("6pack driver for AX.25"); |
| 1012 | MODULE_LICENSE("GPL"); |
| 1013 | MODULE_ALIAS_LDISC(N_6PACK); |
| 1014 | |
| 1015 | module_init(sixpack_init_driver); |
| 1016 | module_exit(sixpack_exit_driver); |