/**************************************************************************** * drivers/net/slip.c * * Copyright (C) 2011-2012, 2015 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Reference: RFC 1055 * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(CONFIG_NET) && defined(CONFIG_NET_SLIP) /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* NOTE: Slip requires UART hardware handshake. If hardware handshake is * not available with your UART, then you might try the 'slattach' option * -L which enable "3-wire operation." That allows operation without the * hardware handshake (but with the possibility of data overrun). */ /* Configuration ************************************************************/ #ifndef CONFIG_NET_NOINTS # warning "CONFIG_NET_NOINTS must be set" #endif #ifndef CONFIG_NET_MULTIBUFFER # warning "CONFIG_NET_MULTIBUFFER must be set" #endif #ifndef CONFIG_SLIP_STACKSIZE # define CONFIG_SLIP_STACKSIZE 2048 #endif #ifndef CONFIG_SLIP_DEFPRIO # define CONFIG_SLIP_DEFPRIO 128 #endif /* The Linux slip module hard-codes its MTU size to 296 (40 bytes for the * IP+TPC headers plus 256 bytes of data). So you might as well set * CONFIG_NET_SLIP_MTU to 296 as well. * * There may be an issue with this setting, however. I see that Linux uses * a MTU of 296 and window of 256, but actually only sends 168 bytes of data: * 40 + 128. I believe that is to allow for the 2x worst cast packet * expansion. Ideally we would like to advertise the 256 MSS, but restrict * uIP to 128 bytes (possibly by modifying the tcp_mss() macro). */ #if CONFIG_NET_SLIP_MTU < 296 # error "CONFIG_NET_SLIP_MTU >= 296 is required" #elif CONFIG_NET_SLIP_MTU > 296 # warning "CONFIG_NET_SLIP_MTU == 296 is optimal" #endif /* CONFIG_SLIP_NINTERFACES determines the number of physical interfaces * that will be supported. */ #ifndef CONFIG_SLIP_NINTERFACES # define CONFIG_SLIP_NINTERFACES 1 #endif /* SLIP special character codes *******************************************/ #define SLIP_END 0300 /* Indicates end of packet */ #define SLIP_ESC 0333 /* Indicates byte stuffing */ #define SLIP_ESC_END 0334 /* ESC ESC_END means SLIP_END data byte */ #define SLIP_ESC_ESC 0335 /* ESC ESC_ESC means ESC data byte */ /* General driver definitions **********************************************/ /* TX poll delay = 1 second = 1000000 microseconds. */ #define SLIP_WDDELAY (1*1000000) #define SLIP_POLLHSEC (1*2) /* Statistics helper */ #ifdef CONFIG_NET_STATISTICS # define SLIP_STAT(p,f) (p->stats.f)++ #else # define SLIP_STAT(p,f) #endif /**************************************************************************** * Private Types ****************************************************************************/ /* Driver statistics */ #ifdef CONFIG_NET_STATISTICS struct slip_statistics_s { uint32_t transmitted; /* Number of packets transmitted */ uint32_t received /* Number of packets received */ }; #endif /* The slip_driver_s encapsulates all state information for a single hardware * interface */ struct slip_driver_s { volatile bool bifup; /* true:ifup false:ifdown */ bool txnodelay; /* True: usleep() not needed */ int16_t fd; /* TTY file descriptor */ uint16_t rxlen; /* The number of bytes in rxbuf */ pid_t rxpid; /* Receiver thread ID */ pid_t txpid; /* Transmitter thread ID */ sem_t waitsem; /* Mutually exclusive access to uIP */ /* Driver statistics */ #ifdef CONFIG_NET_STATISTICS struct slip_statistics_s stats; #endif /* This holds the information visible to uIP/NuttX */ struct net_driver_s dev; /* Interface understood by uIP */ uint8_t rxbuf[CONFIG_NET_SLIP_MTU + 2]; uint8_t txbuf[CONFIG_NET_SLIP_MTU + 2]; }; /**************************************************************************** * Private Data ****************************************************************************/ /* We really should get rid of CONFIG_SLIP_NINTERFACES and, instead, * kmm_malloc() new interface instances as needed. */ static struct slip_driver_s g_slip[CONFIG_SLIP_NINTERFACES]; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static void slip_semtake(FAR struct slip_driver_s *priv); /* Common TX logic */ static void slip_write(FAR struct slip_driver_s *priv, FAR const uint8_t *buffer, int len); static void slip_putc(FAR struct slip_driver_s *priv, int ch); static int slip_transmit(FAR struct slip_driver_s *priv); static int slip_txpoll(FAR struct net_driver_s *dev); static void slip_txtask(int argc, FAR char *argv[]); /* Packet receiver task */ static int slip_getc(FAR struct slip_driver_s *priv); static inline void slip_receive(FAR struct slip_driver_s *priv); static int slip_rxtask(int argc, FAR char *argv[]); /* NuttX callback functions */ static int slip_ifup(FAR struct net_driver_s *dev); static int slip_ifdown(FAR struct net_driver_s *dev); static int slip_txavail(FAR struct net_driver_s *dev); #ifdef CONFIG_NET_IGMP static int slip_addmac(FAR struct net_driver_s *dev, FAR const uint8_t *mac); static int slip_rmmac(FAR struct net_driver_s *dev, FAR const uint8_t *mac); #endif /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: slip_semtake ****************************************************************************/ static void slip_semtake(FAR struct slip_driver_s *priv) { /* Take the semaphore (perhaps waiting) */ while (sem_wait(&priv->waitsem) != 0) { /* The only case that an error should occur here is if * the wait was awakened by a signal. */ ASSERT(errno == EINTR); } } #define slip_semgive(p) sem_post(&(p)->waitsem); /**************************************************************************** * Function: slip_write * * Description: * Just an inline wrapper around fwrite with error checking. * * Parameters: * priv - Reference to the driver state structure * buffer - Buffer data to send * len - Buffer length in bytes * ****************************************************************************/ static inline void slip_write(FAR struct slip_driver_s *priv, FAR const uint8_t *buffer, int len) { /* Handle the case where the write is awakened by a signal */ while (write(priv->fd, buffer, len) < 0) { DEBUGASSERT(errno == EINTR); } } /**************************************************************************** * Function: slip_putc * * Description: * Just an inline wrapper around putc with error checking. * * Parameters: * priv - Reference to the driver state structure * ch - The character to send * ****************************************************************************/ static inline void slip_putc(FAR struct slip_driver_s *priv, int ch) { uint8_t buffer = (uint8_t)ch; slip_write(priv, &buffer, 1); } /**************************************************************************** * Function: slip_transmit * * Description: * Start hardware transmission. Called either from the txdone interrupt * handling or from watchdog based polling. * * Parameters: * priv - Reference to the driver state structure * * Returned Value: * OK on success; a negated errno on failure * ****************************************************************************/ static int slip_transmit(FAR struct slip_driver_s *priv) { uint8_t *src; uint8_t *start; uint8_t esc; int remaining; int len; /* Increment statistics */ nvdbg("Sending packet size %d\n", priv->dev.d_len); SLIP_STAT(priv, transmitted); /* Send an initial END character to flush out any data that may have * accumulated in the receiver due to line noise */ slip_putc(priv, SLIP_END); /* For each byte in the packet, send the appropriate character sequence */ src = priv->dev.d_buf; remaining = priv->dev.d_len; start = src; len = 0; while (remaining-- > 0) { switch (*src) { /* If it's the same code as an END character, we send a special two * character code so as not to make the receiver think we sent an * END */ case SLIP_END: esc = SLIP_ESC_END; goto escape; /* If it's the same code as an ESC character, we send a special two * character code so as not to make the receiver think we sent an * ESC */ case SLIP_ESC: esc = SLIP_ESC_ESC; escape: { /* Flush any unsent data */ if (len > 0) { slip_write(priv, start, len); } /* Reset */ start = src + 1; len = 0; /* Then send the escape sequence */ slip_putc(priv, SLIP_ESC); slip_putc(priv, esc); } break; /* otherwise, just bump up the count */ default: len++; break; } /* Point to the next character in the packet */ src++; } /* We have looked at every character in the packet. Now flush any unsent * data */ if (len > 0) { slip_write(priv, start, len); } /* And send the END token */ slip_putc(priv, SLIP_END); priv->txnodelay = true; return OK; } /**************************************************************************** * Function: slip_txpoll * * Description: * Check if uIP has any outgoing packets ready to send. This is a * callback from devif_poll(). devif_poll() may be called: * * 1. When the preceding TX packet send is complete, or * 2. When the preceding TX packet send times o ]ut and the interface is reset * 3. During normal TX polling * * Parameters: * dev - Reference to the NuttX driver state structure * * Returned Value: * OK on success; a negated errno on failure * * Assumptions: * The initiator of the poll holds the priv->waitsem; * ****************************************************************************/ static int slip_txpoll(FAR struct net_driver_s *dev) { FAR struct slip_driver_s *priv = (FAR struct slip_driver_s *)dev->d_private; /* If the polling resulted in data that should be sent out on the network, * the field d_len is set to a value > 0. */ if (priv->dev.d_len > 0) { slip_transmit(priv); } /* If zero is returned, the polling will continue until all connections have * been examined. */ return 0; } /**************************************************************************** * Function: slip_txtask * * Description: * Polling and transmission is performed on tx thread. * * Parameters: * arg - Reference to the NuttX driver state structure * * Returned Value: * None * ****************************************************************************/ static void slip_txtask(int argc, FAR char *argv[]) { FAR struct slip_driver_s *priv; unsigned int index = *(argv[1]) - '0'; net_lock_t flags; unsigned int msec_start; unsigned int msec_now; unsigned int hsec; ndbg("index: %d\n", index); DEBUGASSERT(index < CONFIG_SLIP_NINTERFACES); /* Get our private data structure instance and wake up the waiting * initialization logic. */ priv = &g_slip[index]; slip_semgive(priv); /* Loop forever */ msec_start = clock_systimer() * MSEC_PER_TICK; for (;;) { /* Wait for the timeout to expire (or until we are signaled by by */ slip_semtake(priv); if (!priv->txnodelay) { slip_semgive(priv); usleep(SLIP_WDDELAY); } else { priv->txnodelay = false; slip_semgive(priv); } /* Is the interface up? */ if (priv->bifup) { /* Get exclusive access to uIP (if it it is already being used * slip_rxtask, then we have to wait). */ slip_semtake(priv); /* Poll the networking layer for new XMIT data. */ flags = net_lock(); priv->dev.d_buf = priv->txbuf; msec_now = clock_systimer() * MSEC_PER_TICK; hsec = (unsigned int)(msec_now - msec_start) / (MSEC_PER_SEC / 2); if (hsec) { (void)devif_timer(&priv->dev, slip_txpoll, hsec); msec_start += hsec * (MSEC_PER_SEC / 2); } else { (void)devif_poll(&priv->dev, slip_uiptxpoll); } net_unlock(flags); slip_semgive(priv); } } } /**************************************************************************** * Function: slip_getc * * Description: * Get one byte from the serial input. * * Parameters: * priv - Reference to the driver state structure * * Returned Value: * The returned byte * ****************************************************************************/ static inline int slip_getc(FAR struct slip_driver_s *priv) { uint8_t ch; while (read(priv->fd, &ch, 1) < 0) { DEBUGASSERT(errno == EINTR); } return (int)ch; } /**************************************************************************** * Function: slip_receive * * Description: * Read a packet from the serial input * * Parameters: * priv - Reference to the driver state structure * * Returned Value: * None * ****************************************************************************/ static inline void slip_receive(FAR struct slip_driver_s *priv) { uint8_t ch; /* Copy the data data from the hardware to to the RX buffer until we * put together a whole packet. Make sure not to copy them into the * packet if we run out of room. */ nvdbg("Receiving packet\n"); for (;;) { /* Get the next character in the stream. */ ch = slip_getc(priv); /* Handle bytestuffing if necessary */ switch (ch) { /* If it's an END character then we're done with the packet. * (OR we are just starting a packet) */ case SLIP_END: { nvdbg("END\n"); /* A minor optimization: if there is no data in the packet, * ignore it. This is meant to avoid bothering IP with all the * empty packets generated by the duplicate END characters which * are in turn sent to try to detect line noise. */ if (priv->rxlen > 0) { nvdbg("Received packet size %d\n", priv->rxlen); return; } } break; /* if it's the same code as an ESC character, wait and get another * character and then figure out what to store in the packet based * on that. */ case SLIP_ESC: { nvdbg("ESC\n"); ch = slip_getc(priv); /* if "ch" is not one of these two, then we have a protocol * violation. The best bet seems to be to leave the byte alone * and just stuff it into the packet */ switch (ch) { case SLIP_ESC_END: nvdbg("ESC-END\n"); ch = SLIP_END; break; case SLIP_ESC_ESC: nvdbg("ESC-ESC\n"); ch = SLIP_ESC; break; default: ndbg("ERROR: Protocol violation: %02x\n", ch); break; } /* Here we fall into the default handler and let it store the * character for us */ } default: { if (priv->rxlen < CONFIG_NET_SLIP_MTU+2) { priv->rxbuf[priv->rxlen++] = ch; } } break; } } } /**************************************************************************** * Function: slip_rxtask * * Description: * Wait for incoming data. * * Parameters: * argc * argv * * Returned Value: * (Does not return) * * Assumptions: * ****************************************************************************/ static int slip_rxtask(int argc, FAR char *argv[]) { FAR struct slip_driver_s *priv; unsigned int index = *(argv[1]) - '0'; net_lock_t flags; int ch; ndbg("index: %d\n", index); DEBUGASSERT(index < CONFIG_SLIP_NINTERFACES); /* Get our private data structure instance and wake up the waiting * initialization logic. */ priv = &g_slip[index]; slip_semgive(priv); /* Loop forever */ for (;;) { /* Wait for the next character to be available on the input stream. */ nvdbg("Waiting...\n"); ch = slip_getc(priv); /* Ignore any input that we receive before the interface is up. */ if (!priv->bifup) { continue; } /* We have something... * * END characters may appear at packet boundaries BEFORE as well as * after the beginning of the packet. This is normal and expected. */ if (ch == SLIP_END) { priv->rxlen = 0; } /* Otherwise, we are in danger of being out-of-sync. Apparently the * leading END character is optional. Let's try to continue. */ else { priv->rxbuf[0] = (uint8_t)ch; priv->rxlen = 1; } /* Copy the data data from the hardware to priv->rxbuf until we put * together a whole packet. */ slip_receive(priv); SLIP_STAT(priv, received); /* All packets are assumed to be IP packets (we don't have a choice.. * there is no Ethernet header containing the EtherType). So pass the * received packet on for IP processing -- but only if it is big * enough to hold an IP header. */ if (priv->rxlen >= IPv4_HDRLEN) { /* Handle the IP input. Get exclusive access to uIP. */ slip_semtake(priv); priv->dev.d_buf = priv->rxbuf; priv->dev.d_len = priv->rxlen; flags = net_lock(); ipv4_input(&priv->dev); /* If the above function invocation resulted in data that should * be sent out on the network, the field d_len will set to a * value > 0. NOTE that we are transmitting using the RX buffer! */ if (priv->dev.d_len > 0) { slip_transmit(priv); kill(priv->txpid, SIGALRM); } net_unlock(flags); slip_semgive(priv); } else { SLIP_STAT(priv, rxsmallpacket); } } /* We won't get here */ return OK; } /**************************************************************************** * Function: slip_ifup * * Description: * NuttX Callback: Bring up the Ethernet interface when an IP address is * provided * * Parameters: * dev - Reference to the NuttX driver state structure * * Returned Value: * None * * Assumptions: * ****************************************************************************/ static int slip_ifup(FAR struct net_driver_s *dev) { FAR struct slip_driver_s *priv = (FAR struct slip_driver_s *)dev->d_private; ndbg("Bringing up: %d.%d.%d.%d\n", dev->d_ipaddr & 0xff, (dev->d_ipaddr >> 8) & 0xff, (dev->d_ipaddr >> 16) & 0xff, dev->d_ipaddr >> 24 ); /* Mark the interface up */ priv->bifup = true; return OK; } /**************************************************************************** * Function: slip_ifdown * * Description: * NuttX Callback: Stop the interface. * * Parameters: * dev - Reference to the NuttX driver state structure * * Returned Value: * None * * Assumptions: * ****************************************************************************/ static int slip_ifdown(FAR struct net_driver_s *dev) { FAR struct slip_driver_s *priv = (FAR struct slip_driver_s *)dev->d_private; /* Mark the device "down" */ priv->bifup = false; return OK; } /**************************************************************************** * Function: slip_txavail * * Description: * Driver callback invoked when new TX data is available. This is a * stimulus perform an out-of-cycle poll and, thereby, reduce the TX * latency. * * Parameters: * dev - Reference to the NuttX driver state structure * * Returned Value: * None * ****************************************************************************/ static int slip_txavail(FAR struct net_driver_s *dev) { FAR struct slip_driver_s *priv = (FAR struct slip_driver_s *)dev->d_private; /* Ignore the notification if the interface is not yet up */ if (priv->bifup) { /* Wake up the TX polling thread */ priv->txnodelay = true; kill(priv->txpid, SIGALRM); } return OK; } /**************************************************************************** * Function: slip_addmac * * Description: * NuttX Callback: Add the specified MAC address to the hardware multicast * address filtering * * Parameters: * dev - Reference to the NuttX driver state structure * mac - The MAC address to be added * * Returned Value: * None * * Assumptions: * ****************************************************************************/ #ifdef CONFIG_NET_IGMP static int slip_addmac(FAR struct net_driver_s *dev, FAR const uint8_t *mac) { FAR struct slip_driver_s *priv = (FAR struct slip_driver_s *)dev->d_private; /* Add the MAC address to the hardware multicast routing table */ return OK; } #endif /**************************************************************************** * Function: slip_rmmac * * Description: * NuttX Callback: Remove the specified MAC address from the hardware multicast * address filtering * * Parameters: * dev - Reference to the NuttX driver state structure * mac - The MAC address to be removed * * Returned Value: * None * * Assumptions: * ****************************************************************************/ #ifdef CONFIG_NET_IGMP static int slip_rmmac(FAR struct net_driver_s *dev, FAR const uint8_t *mac) { FAR struct slip_driver_s *priv = (FAR struct slip_driver_s *)dev->d_private; /* Add the MAC address to the hardware multicast routing table */ return OK; } #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Function: slip_initialize * * Description: * Instantiate a SLIP network interface. * * Parameters: * intf - In the case where there are multiple SLIP interfaces, this value * identifies which is to be initialized. The network name will be, * for example, "/dev/slip5" for intf == 5 * * Returned Value: * OK on success; Negated errno on failure. * * Assumptions: * ****************************************************************************/ int slip_initialize(int intf, FAR const char *devname) { FAR struct slip_driver_s *priv; char buffer[8]; FAR char *argv[2]; /* Get the interface structure associated with this interface number. */ DEBUGASSERT(intf < CONFIG_SLIP_NINTERFACES); priv = &g_slip[intf]; /* Initialize the driver structure */ memset(priv, 0, sizeof(struct slip_driver_s)); priv->dev.d_ifup = slip_ifup; /* I/F up (new IP address) callback */ priv->dev.d_ifdown = slip_ifdown; /* I/F down callback */ priv->dev.d_txavail = slip_txavail; /* New TX data callback */ #ifdef CONFIG_NET_IGMP priv->dev.d_addmac = slip_addmac; /* Add multicast MAC address */ priv->dev.d_rmmac = slip_rmmac; /* Remove multicast MAC address */ #endif priv->dev.d_private = priv; /* Used to recover private state from dev */ /* Open the device */ priv->fd = open(devname, O_RDWR, 0666); if (priv->fd < 0) { ndbg("ERROR: Failed to open %s: %d\n", devname, errno); return -errno; } /* Initialize the wait semaphore */ sem_init(&priv->waitsem, 0, 0); /* Put the interface in the down state. This usually amounts to resetting * the device and/or calling slip_ifdown(). */ slip_ifdown(&priv->dev); /* Start the SLIP receiver task */ snprintf(buffer, 8, "%d", intf); argv[0] = buffer; argv[1] = NULL; priv->rxpid = task_create("rxslip", CONFIG_SLIP_DEFPRIO, CONFIG_SLIP_STACKSIZE, (main_t)slip_rxtask, (FAR char * const *)argv); if (priv->rxpid < 0) { ndbg("ERROR: Failed to start receiver task\n"); return -errno; } /* Wait and make sure that the receive task is started. */ slip_semtake(priv); /* Start the SLIP transmitter task */ priv->txpid = task_create("txslip", CONFIG_SLIP_DEFPRIO, CONFIG_SLIP_STACKSIZE, (main_t)slip_txtask, (FAR char * const *)argv); if (priv->txpid < 0) { ndbg("ERROR: Failed to start receiver task\n"); return -errno; } /* Wait and make sure that the transmit task is started. */ slip_semtake(priv); /* Bump the semaphore count so that it can now be used as a mutex */ slip_semgive(priv); /* Register the device with the OS so that socket IOCTLs can be performed */ (void)netdev_register(&priv->dev, NET_LL_SLIP); /* When the RX and TX tasks were created, the TTY file descriptor was * dup'ed for each task. This task no longer needs the file descriptor * and we can safely close it. */ close(priv->fd); return OK; } #endif /* CONFIG_NET && CONFIG_NET_SLIP */