Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 1 | /* |
| 2 | * slcan.c - serial line CAN interface driver (using tty line discipline) |
| 3 | * |
Paul Gortmaker | 3396c78 | 2012-01-27 13:36:01 +0000 | [diff] [blame] | 4 | * This file is derived from linux/drivers/net/slip/slip.c |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 5 | * |
| 6 | * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk> |
| 7 | * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org> |
| 8 | * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net> |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify it |
| 11 | * under the terms of the GNU General Public License as published by the |
| 12 | * Free Software Foundation; either version 2 of the License, or (at your |
| 13 | * option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, but |
| 16 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 18 | * General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU General Public License along |
Jeff Kirsher | 05780d9 | 2013-12-06 06:28:45 -0800 | [diff] [blame] | 21 | * with this program; if not, see http://www.gnu.org/licenses/gpl.html |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 22 | * |
| 23 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 24 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 25 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 26 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 27 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 28 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 29 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 30 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 31 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 32 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 33 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
| 34 | * DAMAGE. |
| 35 | * |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 36 | */ |
| 37 | |
| 38 | #include <linux/module.h> |
| 39 | #include <linux/moduleparam.h> |
| 40 | |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 41 | #include <linux/uaccess.h> |
| 42 | #include <linux/bitops.h> |
| 43 | #include <linux/string.h> |
| 44 | #include <linux/tty.h> |
| 45 | #include <linux/errno.h> |
| 46 | #include <linux/netdevice.h> |
| 47 | #include <linux/skbuff.h> |
| 48 | #include <linux/rtnetlink.h> |
| 49 | #include <linux/if_arp.h> |
| 50 | #include <linux/if_ether.h> |
David S. Miller | 84b3cdc | 2010-12-08 18:41:03 -0800 | [diff] [blame] | 51 | #include <linux/sched.h> |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 52 | #include <linux/delay.h> |
| 53 | #include <linux/init.h> |
Andy Shevchenko | 81fc70d | 2011-07-17 22:26:37 +0000 | [diff] [blame] | 54 | #include <linux/kernel.h> |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 55 | #include <linux/can.h> |
Oliver Hartkopp | 156c2bb | 2013-01-17 18:43:39 +0100 | [diff] [blame] | 56 | #include <linux/can/skb.h> |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 57 | |
Andi Kleen | c477ebd | 2012-10-04 17:11:55 -0700 | [diff] [blame] | 58 | static __initconst const char banner[] = |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 59 | KERN_INFO "slcan: serial line CAN interface driver\n"; |
| 60 | |
| 61 | MODULE_ALIAS_LDISC(N_SLCAN); |
| 62 | MODULE_DESCRIPTION("serial line CAN interface"); |
| 63 | MODULE_LICENSE("GPL"); |
| 64 | MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>"); |
| 65 | |
| 66 | #define SLCAN_MAGIC 0x53CA |
| 67 | |
| 68 | static int maxdev = 10; /* MAX number of SLCAN channels; |
| 69 | This can be overridden with |
| 70 | insmod slcan.ko maxdev=nnn */ |
| 71 | module_param(maxdev, int, 0); |
| 72 | MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces"); |
| 73 | |
| 74 | /* maximum rx buffer len: extended CAN frame with timestamp */ |
| 75 | #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1) |
| 76 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 77 | #define SLC_CMD_LEN 1 |
| 78 | #define SLC_SFF_ID_LEN 3 |
| 79 | #define SLC_EFF_ID_LEN 8 |
| 80 | |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 81 | struct slcan { |
| 82 | int magic; |
| 83 | |
| 84 | /* Various fields. */ |
| 85 | struct tty_struct *tty; /* ptr to TTY structure */ |
| 86 | struct net_device *dev; /* easy for intr handling */ |
| 87 | spinlock_t lock; |
| 88 | |
| 89 | /* These are pointers to the malloc()ed frame buffers. */ |
| 90 | unsigned char rbuff[SLC_MTU]; /* receiver buffer */ |
| 91 | int rcount; /* received chars counter */ |
| 92 | unsigned char xbuff[SLC_MTU]; /* transmitter buffer */ |
| 93 | unsigned char *xhead; /* pointer to next XMIT byte */ |
| 94 | int xleft; /* bytes left in XMIT queue */ |
| 95 | |
| 96 | unsigned long flags; /* Flag values/ mode etc */ |
| 97 | #define SLF_INUSE 0 /* Channel in use */ |
| 98 | #define SLF_ERROR 1 /* Parity, etc. error */ |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 99 | }; |
| 100 | |
| 101 | static struct net_device **slcan_devs; |
| 102 | |
| 103 | /************************************************************************ |
| 104 | * SLCAN ENCAPSULATION FORMAT * |
| 105 | ************************************************************************/ |
| 106 | |
| 107 | /* |
| 108 | * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended |
| 109 | * frame format) a data length code (can_dlc) which can be from 0 to 8 |
| 110 | * and up to <can_dlc> data bytes as payload. |
| 111 | * Additionally a CAN frame may become a remote transmission frame if the |
| 112 | * RTR-bit is set. This causes another ECU to send a CAN frame with the |
| 113 | * given can_id. |
| 114 | * |
| 115 | * The SLCAN ASCII representation of these different frame types is: |
| 116 | * <type> <id> <dlc> <data>* |
| 117 | * |
| 118 | * Extended frames (29 bit) are defined by capital characters in the type. |
| 119 | * RTR frames are defined as 'r' types - normal frames have 't' type: |
| 120 | * t => 11 bit data frame |
| 121 | * r => 11 bit RTR frame |
| 122 | * T => 29 bit data frame |
| 123 | * R => 29 bit RTR frame |
| 124 | * |
| 125 | * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64). |
| 126 | * The <dlc> is a one byte ASCII number ('0' - '8') |
| 127 | * The <data> section has at much ASCII Hex bytes as defined by the <dlc> |
| 128 | * |
| 129 | * Examples: |
| 130 | * |
| 131 | * t1230 : can_id 0x123, can_dlc 0, no data |
| 132 | * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33 |
| 133 | * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55 |
| 134 | * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request |
| 135 | * |
| 136 | */ |
| 137 | |
| 138 | /************************************************************************ |
| 139 | * STANDARD SLCAN DECAPSULATION * |
| 140 | ************************************************************************/ |
| 141 | |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 142 | /* Send one completely decapsulated can_frame to the network layer */ |
| 143 | static void slc_bump(struct slcan *sl) |
| 144 | { |
| 145 | struct sk_buff *skb; |
| 146 | struct can_frame cf; |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 147 | int i, tmp; |
| 148 | u32 tmpid; |
| 149 | char *cmd = sl->rbuff; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 150 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 151 | cf.can_id = 0; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 152 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 153 | switch (*cmd) { |
| 154 | case 'r': |
| 155 | cf.can_id = CAN_RTR_FLAG; |
| 156 | /* fallthrough */ |
| 157 | case 't': |
| 158 | /* store dlc ASCII value and terminate SFF CAN ID string */ |
| 159 | cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN]; |
| 160 | sl->rbuff[SLC_CMD_LEN + SLC_SFF_ID_LEN] = 0; |
| 161 | /* point to payload data behind the dlc */ |
| 162 | cmd += SLC_CMD_LEN + SLC_SFF_ID_LEN + 1; |
| 163 | break; |
| 164 | case 'R': |
| 165 | cf.can_id = CAN_RTR_FLAG; |
| 166 | /* fallthrough */ |
| 167 | case 'T': |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 168 | cf.can_id |= CAN_EFF_FLAG; |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 169 | /* store dlc ASCII value and terminate EFF CAN ID string */ |
| 170 | cf.can_dlc = sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN]; |
| 171 | sl->rbuff[SLC_CMD_LEN + SLC_EFF_ID_LEN] = 0; |
| 172 | /* point to payload data behind the dlc */ |
| 173 | cmd += SLC_CMD_LEN + SLC_EFF_ID_LEN + 1; |
| 174 | break; |
| 175 | default: |
| 176 | return; |
| 177 | } |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 178 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 179 | if (kstrtou32(sl->rbuff + SLC_CMD_LEN, 16, &tmpid)) |
| 180 | return; |
| 181 | |
| 182 | cf.can_id |= tmpid; |
| 183 | |
| 184 | /* get can_dlc from sanitized ASCII value */ |
| 185 | if (cf.can_dlc >= '0' && cf.can_dlc < '9') |
| 186 | cf.can_dlc -= '0'; |
| 187 | else |
| 188 | return; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 189 | |
| 190 | *(u64 *) (&cf.data) = 0; /* clear payload */ |
| 191 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 192 | /* RTR frames may have a dlc > 0 but they never have any data bytes */ |
| 193 | if (!(cf.can_id & CAN_RTR_FLAG)) { |
| 194 | for (i = 0; i < cf.can_dlc; i++) { |
| 195 | tmp = hex_to_bin(*cmd++); |
| 196 | if (tmp < 0) |
| 197 | return; |
| 198 | cf.data[i] = (tmp << 4); |
| 199 | tmp = hex_to_bin(*cmd++); |
| 200 | if (tmp < 0) |
| 201 | return; |
| 202 | cf.data[i] |= tmp; |
| 203 | } |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 204 | } |
| 205 | |
Oliver Hartkopp | 156c2bb | 2013-01-17 18:43:39 +0100 | [diff] [blame] | 206 | skb = dev_alloc_skb(sizeof(struct can_frame) + |
| 207 | sizeof(struct can_skb_priv)); |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 208 | if (!skb) |
| 209 | return; |
| 210 | |
| 211 | skb->dev = sl->dev; |
| 212 | skb->protocol = htons(ETH_P_CAN); |
| 213 | skb->pkt_type = PACKET_BROADCAST; |
| 214 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
Oliver Hartkopp | 156c2bb | 2013-01-17 18:43:39 +0100 | [diff] [blame] | 215 | |
Oliver Hartkopp | 2bf3440 | 2013-01-28 08:33:33 +0000 | [diff] [blame] | 216 | can_skb_reserve(skb); |
| 217 | can_skb_prv(skb)->ifindex = sl->dev->ifindex; |
Oliver Hartkopp | 156c2bb | 2013-01-17 18:43:39 +0100 | [diff] [blame] | 218 | |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 219 | memcpy(skb_put(skb, sizeof(struct can_frame)), |
| 220 | &cf, sizeof(struct can_frame)); |
Oliver Hartkopp | 174c95d | 2011-08-10 05:18:59 +0000 | [diff] [blame] | 221 | netif_rx_ni(skb); |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 222 | |
| 223 | sl->dev->stats.rx_packets++; |
| 224 | sl->dev->stats.rx_bytes += cf.can_dlc; |
| 225 | } |
| 226 | |
| 227 | /* parse tty input stream */ |
| 228 | static void slcan_unesc(struct slcan *sl, unsigned char s) |
| 229 | { |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 230 | if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */ |
| 231 | if (!test_and_clear_bit(SLF_ERROR, &sl->flags) && |
| 232 | (sl->rcount > 4)) { |
| 233 | slc_bump(sl); |
| 234 | } |
| 235 | sl->rcount = 0; |
| 236 | } else { |
| 237 | if (!test_bit(SLF_ERROR, &sl->flags)) { |
| 238 | if (sl->rcount < SLC_MTU) { |
| 239 | sl->rbuff[sl->rcount++] = s; |
| 240 | return; |
| 241 | } else { |
| 242 | sl->dev->stats.rx_over_errors++; |
| 243 | set_bit(SLF_ERROR, &sl->flags); |
| 244 | } |
| 245 | } |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /************************************************************************ |
| 250 | * STANDARD SLCAN ENCAPSULATION * |
| 251 | ************************************************************************/ |
| 252 | |
| 253 | /* Encapsulate one can_frame and stuff into a TTY queue. */ |
| 254 | static void slc_encaps(struct slcan *sl, struct can_frame *cf) |
| 255 | { |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 256 | int actual, i; |
| 257 | unsigned char *pos; |
| 258 | unsigned char *endpos; |
| 259 | canid_t id = cf->can_id; |
| 260 | |
| 261 | pos = sl->xbuff; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 262 | |
| 263 | if (cf->can_id & CAN_RTR_FLAG) |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 264 | *pos = 'R'; /* becomes 'r' in standard frame format (SFF) */ |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 265 | else |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 266 | *pos = 'T'; /* becomes 't' in standard frame format (SSF) */ |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 267 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 268 | /* determine number of chars for the CAN-identifier */ |
| 269 | if (cf->can_id & CAN_EFF_FLAG) { |
| 270 | id &= CAN_EFF_MASK; |
| 271 | endpos = pos + SLC_EFF_ID_LEN; |
| 272 | } else { |
| 273 | *pos |= 0x20; /* convert R/T to lower case for SFF */ |
| 274 | id &= CAN_SFF_MASK; |
| 275 | endpos = pos + SLC_SFF_ID_LEN; |
| 276 | } |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 277 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 278 | /* build 3 (SFF) or 8 (EFF) digit CAN identifier */ |
| 279 | pos++; |
| 280 | while (endpos >= pos) { |
| 281 | *endpos-- = hex_asc_upper[id & 0xf]; |
| 282 | id >>= 4; |
| 283 | } |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 284 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 285 | pos += (cf->can_id & CAN_EFF_FLAG) ? SLC_EFF_ID_LEN : SLC_SFF_ID_LEN; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 286 | |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 287 | *pos++ = cf->can_dlc + '0'; |
| 288 | |
| 289 | /* RTR frames may have a dlc > 0 but they never have any data bytes */ |
| 290 | if (!(cf->can_id & CAN_RTR_FLAG)) { |
| 291 | for (i = 0; i < cf->can_dlc; i++) |
| 292 | pos = hex_byte_pack_upper(pos, cf->data[i]); |
| 293 | } |
| 294 | |
| 295 | *pos++ = '\r'; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 296 | |
| 297 | /* Order of next two lines is *very* important. |
| 298 | * When we are sending a little amount of data, |
| 299 | * the transfer may be completed inside the ops->write() |
| 300 | * routine, because it's running with interrupts enabled. |
| 301 | * In this case we *never* got WRITE_WAKEUP event, |
| 302 | * if we did not request it before write operation. |
| 303 | * 14 Oct 1994 Dmitry Gorodchanin. |
| 304 | */ |
| 305 | set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); |
Andre Naujoks | 87397fe | 2013-09-13 19:37:13 +0200 | [diff] [blame] | 306 | actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff); |
| 307 | sl->xleft = (pos - sl->xbuff) - actual; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 308 | sl->xhead = sl->xbuff + actual; |
| 309 | sl->dev->stats.tx_bytes += cf->can_dlc; |
| 310 | } |
| 311 | |
| 312 | /* |
| 313 | * Called by the driver when there's room for more data. If we have |
| 314 | * more packets to send, we send them here. |
| 315 | */ |
| 316 | static void slcan_write_wakeup(struct tty_struct *tty) |
| 317 | { |
| 318 | int actual; |
| 319 | struct slcan *sl = (struct slcan *) tty->disc_data; |
| 320 | |
| 321 | /* First make sure we're connected. */ |
| 322 | if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) |
| 323 | return; |
| 324 | |
Alexander Stein | 367525c | 2014-04-15 16:51:04 +0200 | [diff] [blame] | 325 | spin_lock_bh(&sl->lock); |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 326 | if (sl->xleft <= 0) { |
| 327 | /* Now serial buffer is almost free & we can start |
| 328 | * transmission of another packet */ |
| 329 | sl->dev->stats.tx_packets++; |
| 330 | clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); |
Alexander Stein | 367525c | 2014-04-15 16:51:04 +0200 | [diff] [blame] | 331 | spin_unlock_bh(&sl->lock); |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 332 | netif_wake_queue(sl->dev); |
| 333 | return; |
| 334 | } |
| 335 | |
| 336 | actual = tty->ops->write(tty, sl->xhead, sl->xleft); |
| 337 | sl->xleft -= actual; |
| 338 | sl->xhead += actual; |
Alexander Stein | 367525c | 2014-04-15 16:51:04 +0200 | [diff] [blame] | 339 | spin_unlock_bh(&sl->lock); |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 340 | } |
| 341 | |
| 342 | /* Send a can_frame to a TTY queue. */ |
| 343 | static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev) |
| 344 | { |
| 345 | struct slcan *sl = netdev_priv(dev); |
| 346 | |
| 347 | if (skb->len != sizeof(struct can_frame)) |
| 348 | goto out; |
| 349 | |
| 350 | spin_lock(&sl->lock); |
| 351 | if (!netif_running(dev)) { |
| 352 | spin_unlock(&sl->lock); |
| 353 | printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name); |
| 354 | goto out; |
| 355 | } |
| 356 | if (sl->tty == NULL) { |
| 357 | spin_unlock(&sl->lock); |
| 358 | goto out; |
| 359 | } |
| 360 | |
| 361 | netif_stop_queue(sl->dev); |
| 362 | slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */ |
| 363 | spin_unlock(&sl->lock); |
| 364 | |
| 365 | out: |
| 366 | kfree_skb(skb); |
| 367 | return NETDEV_TX_OK; |
| 368 | } |
| 369 | |
| 370 | |
| 371 | /****************************************** |
| 372 | * Routines looking at netdevice side. |
| 373 | ******************************************/ |
| 374 | |
| 375 | /* Netdevice UP -> DOWN routine */ |
| 376 | static int slc_close(struct net_device *dev) |
| 377 | { |
| 378 | struct slcan *sl = netdev_priv(dev); |
| 379 | |
| 380 | spin_lock_bh(&sl->lock); |
| 381 | if (sl->tty) { |
| 382 | /* TTY discipline is running. */ |
| 383 | clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags); |
| 384 | } |
| 385 | netif_stop_queue(dev); |
| 386 | sl->rcount = 0; |
| 387 | sl->xleft = 0; |
| 388 | spin_unlock_bh(&sl->lock); |
| 389 | |
| 390 | return 0; |
| 391 | } |
| 392 | |
| 393 | /* Netdevice DOWN -> UP routine */ |
| 394 | static int slc_open(struct net_device *dev) |
| 395 | { |
| 396 | struct slcan *sl = netdev_priv(dev); |
| 397 | |
| 398 | if (sl->tty == NULL) |
| 399 | return -ENODEV; |
| 400 | |
| 401 | sl->flags &= (1 << SLF_INUSE); |
| 402 | netif_start_queue(dev); |
| 403 | return 0; |
| 404 | } |
| 405 | |
| 406 | /* Hook the destructor so we can free slcan devs at the right point in time */ |
| 407 | static void slc_free_netdev(struct net_device *dev) |
| 408 | { |
| 409 | int i = dev->base_addr; |
| 410 | free_netdev(dev); |
| 411 | slcan_devs[i] = NULL; |
| 412 | } |
| 413 | |
Oliver Hartkopp | c971fa2 | 2014-03-07 09:23:41 +0100 | [diff] [blame] | 414 | static int slcan_change_mtu(struct net_device *dev, int new_mtu) |
| 415 | { |
| 416 | return -EINVAL; |
| 417 | } |
| 418 | |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 419 | static const struct net_device_ops slc_netdev_ops = { |
| 420 | .ndo_open = slc_open, |
| 421 | .ndo_stop = slc_close, |
| 422 | .ndo_start_xmit = slc_xmit, |
Oliver Hartkopp | c971fa2 | 2014-03-07 09:23:41 +0100 | [diff] [blame] | 423 | .ndo_change_mtu = slcan_change_mtu, |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 424 | }; |
| 425 | |
| 426 | static void slc_setup(struct net_device *dev) |
| 427 | { |
| 428 | dev->netdev_ops = &slc_netdev_ops; |
| 429 | dev->destructor = slc_free_netdev; |
| 430 | |
| 431 | dev->hard_header_len = 0; |
| 432 | dev->addr_len = 0; |
| 433 | dev->tx_queue_len = 10; |
| 434 | |
| 435 | dev->mtu = sizeof(struct can_frame); |
| 436 | dev->type = ARPHRD_CAN; |
| 437 | |
| 438 | /* New-style flags. */ |
| 439 | dev->flags = IFF_NOARP; |
Michał Mirosław | 34324dc | 2011-11-15 15:29:55 +0000 | [diff] [blame] | 440 | dev->features = NETIF_F_HW_CSUM; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 441 | } |
| 442 | |
| 443 | /****************************************** |
| 444 | Routines looking at TTY side. |
| 445 | ******************************************/ |
| 446 | |
| 447 | /* |
| 448 | * Handle the 'receiver data ready' interrupt. |
| 449 | * This function is called by the 'tty_io' module in the kernel when |
| 450 | * a block of SLCAN data has been received, which can now be decapsulated |
| 451 | * and sent on to some IP layer for further processing. This will not |
| 452 | * be re-entered while running but other ldisc functions may be called |
| 453 | * in parallel |
| 454 | */ |
| 455 | |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 456 | static void slcan_receive_buf(struct tty_struct *tty, |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 457 | const unsigned char *cp, char *fp, int count) |
| 458 | { |
| 459 | struct slcan *sl = (struct slcan *) tty->disc_data; |
| 460 | |
| 461 | if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev)) |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 462 | return; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 463 | |
| 464 | /* Read the characters out of the buffer */ |
Linus Torvalds | 55db4c6 | 2011-06-04 06:33:24 +0900 | [diff] [blame] | 465 | while (count--) { |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 466 | if (fp && *fp++) { |
| 467 | if (!test_and_set_bit(SLF_ERROR, &sl->flags)) |
| 468 | sl->dev->stats.rx_errors++; |
| 469 | cp++; |
| 470 | continue; |
| 471 | } |
| 472 | slcan_unesc(sl, *cp++); |
| 473 | } |
| 474 | } |
| 475 | |
| 476 | /************************************ |
| 477 | * slcan_open helper routines. |
| 478 | ************************************/ |
| 479 | |
| 480 | /* Collect hanged up channels */ |
| 481 | static void slc_sync(void) |
| 482 | { |
| 483 | int i; |
| 484 | struct net_device *dev; |
| 485 | struct slcan *sl; |
| 486 | |
| 487 | for (i = 0; i < maxdev; i++) { |
| 488 | dev = slcan_devs[i]; |
| 489 | if (dev == NULL) |
| 490 | break; |
| 491 | |
| 492 | sl = netdev_priv(dev); |
Matvejchikov Ilya | 7ad711b | 2011-07-18 21:58:48 +0000 | [diff] [blame] | 493 | if (sl->tty) |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 494 | continue; |
| 495 | if (dev->flags & IFF_UP) |
| 496 | dev_close(dev); |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | /* Find a free SLCAN channel, and link in this `tty' line. */ |
| 501 | static struct slcan *slc_alloc(dev_t line) |
| 502 | { |
| 503 | int i; |
Oliver Hartkopp | 2af4ba8 | 2011-07-14 21:49:19 +0000 | [diff] [blame] | 504 | char name[IFNAMSIZ]; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 505 | struct net_device *dev = NULL; |
| 506 | struct slcan *sl; |
| 507 | |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 508 | for (i = 0; i < maxdev; i++) { |
| 509 | dev = slcan_devs[i]; |
| 510 | if (dev == NULL) |
| 511 | break; |
| 512 | |
| 513 | } |
| 514 | |
| 515 | /* Sorry, too many, all slots in use */ |
| 516 | if (i >= maxdev) |
| 517 | return NULL; |
| 518 | |
Oliver Hartkopp | 2af4ba8 | 2011-07-14 21:49:19 +0000 | [diff] [blame] | 519 | sprintf(name, "slcan%d", i); |
| 520 | dev = alloc_netdev(sizeof(*sl), name, slc_setup); |
| 521 | if (!dev) |
| 522 | return NULL; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 523 | |
Oliver Hartkopp | 2af4ba8 | 2011-07-14 21:49:19 +0000 | [diff] [blame] | 524 | dev->base_addr = i; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 525 | sl = netdev_priv(dev); |
| 526 | |
| 527 | /* Initialize channel control data */ |
| 528 | sl->magic = SLCAN_MAGIC; |
| 529 | sl->dev = dev; |
| 530 | spin_lock_init(&sl->lock); |
| 531 | slcan_devs[i] = dev; |
| 532 | |
| 533 | return sl; |
| 534 | } |
| 535 | |
| 536 | /* |
| 537 | * Open the high-level part of the SLCAN channel. |
| 538 | * This function is called by the TTY module when the |
| 539 | * SLCAN line discipline is called for. Because we are |
| 540 | * sure the tty line exists, we only have to link it to |
| 541 | * a free SLCAN channel... |
| 542 | * |
| 543 | * Called in process context serialized from other ldisc calls. |
| 544 | */ |
| 545 | |
| 546 | static int slcan_open(struct tty_struct *tty) |
| 547 | { |
| 548 | struct slcan *sl; |
| 549 | int err; |
| 550 | |
| 551 | if (!capable(CAP_NET_ADMIN)) |
| 552 | return -EPERM; |
| 553 | |
| 554 | if (tty->ops->write == NULL) |
| 555 | return -EOPNOTSUPP; |
| 556 | |
| 557 | /* RTnetlink lock is misused here to serialize concurrent |
| 558 | opens of slcan channels. There are better ways, but it is |
| 559 | the simplest one. |
| 560 | */ |
| 561 | rtnl_lock(); |
| 562 | |
| 563 | /* Collect hanged up channels. */ |
| 564 | slc_sync(); |
| 565 | |
| 566 | sl = tty->disc_data; |
| 567 | |
| 568 | err = -EEXIST; |
| 569 | /* First make sure we're not already connected. */ |
| 570 | if (sl && sl->magic == SLCAN_MAGIC) |
| 571 | goto err_exit; |
| 572 | |
| 573 | /* OK. Find a free SLCAN channel to use. */ |
| 574 | err = -ENFILE; |
| 575 | sl = slc_alloc(tty_devnum(tty)); |
| 576 | if (sl == NULL) |
| 577 | goto err_exit; |
| 578 | |
| 579 | sl->tty = tty; |
| 580 | tty->disc_data = sl; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 581 | |
| 582 | if (!test_bit(SLF_INUSE, &sl->flags)) { |
| 583 | /* Perform the low-level SLCAN initialization. */ |
| 584 | sl->rcount = 0; |
| 585 | sl->xleft = 0; |
| 586 | |
| 587 | set_bit(SLF_INUSE, &sl->flags); |
| 588 | |
| 589 | err = register_netdevice(sl->dev); |
| 590 | if (err) |
| 591 | goto err_free_chan; |
| 592 | } |
| 593 | |
| 594 | /* Done. We have linked the TTY line to a channel. */ |
| 595 | rtnl_unlock(); |
| 596 | tty->receive_room = 65536; /* We don't flow control */ |
Oliver Hartkopp | 0d4420a | 2011-05-10 13:12:30 -0700 | [diff] [blame] | 597 | |
| 598 | /* TTY layer expects 0 on success */ |
| 599 | return 0; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 600 | |
| 601 | err_free_chan: |
| 602 | sl->tty = NULL; |
| 603 | tty->disc_data = NULL; |
| 604 | clear_bit(SLF_INUSE, &sl->flags); |
| 605 | |
| 606 | err_exit: |
| 607 | rtnl_unlock(); |
| 608 | |
| 609 | /* Count references from TTY module */ |
| 610 | return err; |
| 611 | } |
| 612 | |
| 613 | /* |
| 614 | * Close down a SLCAN channel. |
| 615 | * This means flushing out any pending queues, and then returning. This |
| 616 | * call is serialized against other ldisc functions. |
| 617 | * |
| 618 | * We also use this method for a hangup event. |
| 619 | */ |
| 620 | |
| 621 | static void slcan_close(struct tty_struct *tty) |
| 622 | { |
| 623 | struct slcan *sl = (struct slcan *) tty->disc_data; |
| 624 | |
| 625 | /* First make sure we're connected. */ |
| 626 | if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty) |
| 627 | return; |
| 628 | |
| 629 | tty->disc_data = NULL; |
| 630 | sl->tty = NULL; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 631 | |
| 632 | /* Flush network side */ |
| 633 | unregister_netdev(sl->dev); |
| 634 | /* This will complete via sl_free_netdev */ |
| 635 | } |
| 636 | |
| 637 | static int slcan_hangup(struct tty_struct *tty) |
| 638 | { |
| 639 | slcan_close(tty); |
| 640 | return 0; |
| 641 | } |
| 642 | |
| 643 | /* Perform I/O control on an active SLCAN channel. */ |
| 644 | static int slcan_ioctl(struct tty_struct *tty, struct file *file, |
| 645 | unsigned int cmd, unsigned long arg) |
| 646 | { |
| 647 | struct slcan *sl = (struct slcan *) tty->disc_data; |
| 648 | unsigned int tmp; |
| 649 | |
| 650 | /* First make sure we're connected. */ |
| 651 | if (!sl || sl->magic != SLCAN_MAGIC) |
| 652 | return -EINVAL; |
| 653 | |
| 654 | switch (cmd) { |
| 655 | case SIOCGIFNAME: |
| 656 | tmp = strlen(sl->dev->name) + 1; |
| 657 | if (copy_to_user((void __user *)arg, sl->dev->name, tmp)) |
| 658 | return -EFAULT; |
| 659 | return 0; |
| 660 | |
| 661 | case SIOCSIFHWADDR: |
| 662 | return -EINVAL; |
| 663 | |
| 664 | default: |
| 665 | return tty_mode_ioctl(tty, file, cmd, arg); |
| 666 | } |
| 667 | } |
| 668 | |
| 669 | static struct tty_ldisc_ops slc_ldisc = { |
| 670 | .owner = THIS_MODULE, |
| 671 | .magic = TTY_LDISC_MAGIC, |
| 672 | .name = "slcan", |
| 673 | .open = slcan_open, |
| 674 | .close = slcan_close, |
| 675 | .hangup = slcan_hangup, |
| 676 | .ioctl = slcan_ioctl, |
| 677 | .receive_buf = slcan_receive_buf, |
| 678 | .write_wakeup = slcan_write_wakeup, |
| 679 | }; |
| 680 | |
| 681 | static int __init slcan_init(void) |
| 682 | { |
| 683 | int status; |
| 684 | |
| 685 | if (maxdev < 4) |
| 686 | maxdev = 4; /* Sanity */ |
| 687 | |
| 688 | printk(banner); |
| 689 | printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev); |
| 690 | |
| 691 | slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL); |
Joe Perches | e404dec | 2012-01-29 12:56:23 +0000 | [diff] [blame] | 692 | if (!slcan_devs) |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 693 | return -ENOMEM; |
Oliver Hartkopp | a1044e3 | 2010-12-02 10:57:59 +0000 | [diff] [blame] | 694 | |
| 695 | /* Fill in our line protocol discipline, and register it */ |
| 696 | status = tty_register_ldisc(N_SLCAN, &slc_ldisc); |
| 697 | if (status) { |
| 698 | printk(KERN_ERR "slcan: can't register line discipline\n"); |
| 699 | kfree(slcan_devs); |
| 700 | } |
| 701 | return status; |
| 702 | } |
| 703 | |
| 704 | static void __exit slcan_exit(void) |
| 705 | { |
| 706 | int i; |
| 707 | struct net_device *dev; |
| 708 | struct slcan *sl; |
| 709 | unsigned long timeout = jiffies + HZ; |
| 710 | int busy = 0; |
| 711 | |
| 712 | if (slcan_devs == NULL) |
| 713 | return; |
| 714 | |
| 715 | /* First of all: check for active disciplines and hangup them. |
| 716 | */ |
| 717 | do { |
| 718 | if (busy) |
| 719 | msleep_interruptible(100); |
| 720 | |
| 721 | busy = 0; |
| 722 | for (i = 0; i < maxdev; i++) { |
| 723 | dev = slcan_devs[i]; |
| 724 | if (!dev) |
| 725 | continue; |
| 726 | sl = netdev_priv(dev); |
| 727 | spin_lock_bh(&sl->lock); |
| 728 | if (sl->tty) { |
| 729 | busy++; |
| 730 | tty_hangup(sl->tty); |
| 731 | } |
| 732 | spin_unlock_bh(&sl->lock); |
| 733 | } |
| 734 | } while (busy && time_before(jiffies, timeout)); |
| 735 | |
| 736 | /* FIXME: hangup is async so we should wait when doing this second |
| 737 | phase */ |
| 738 | |
| 739 | for (i = 0; i < maxdev; i++) { |
| 740 | dev = slcan_devs[i]; |
| 741 | if (!dev) |
| 742 | continue; |
| 743 | slcan_devs[i] = NULL; |
| 744 | |
| 745 | sl = netdev_priv(dev); |
| 746 | if (sl->tty) { |
| 747 | printk(KERN_ERR "%s: tty discipline still running\n", |
| 748 | dev->name); |
| 749 | /* Intentionally leak the control block. */ |
| 750 | dev->destructor = NULL; |
| 751 | } |
| 752 | |
| 753 | unregister_netdev(dev); |
| 754 | } |
| 755 | |
| 756 | kfree(slcan_devs); |
| 757 | slcan_devs = NULL; |
| 758 | |
| 759 | i = tty_unregister_ldisc(N_SLCAN); |
| 760 | if (i) |
| 761 | printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i); |
| 762 | } |
| 763 | |
| 764 | module_init(slcan_init); |
| 765 | module_exit(slcan_exit); |