/**************************************************************************** * drivers/net/telnet.c * * Copyright (C) 2007, 2009, 2011-2013, 2017, 2019, 2020 Gregory Nutt. All * rights reserved. * Author: Gregory Nutt * * This derives remotely from some Telnet logic from uIP which has a * compatible BSD license: * * Author: Adam Dunkels * Copyright (c) 2003, Adam Dunkels. * All rights reserved. * * 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 of the Institute, 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 INSTITUTE 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 INSTITUTE 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 #ifdef CONFIG_NETDEV_TELNET /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Configuration ************************************************************/ #ifndef CONFIG_TELNET_RXBUFFER_SIZE # define CONFIG_TELNET_RXBUFFER_SIZE 256 #endif #ifndef CONFIG_TELNET_TXBUFFER_SIZE # define CONFIG_TELNET_TXBUFFER_SIZE 256 #endif #ifndef CONFIG_TELNET_MAXLCLIENTS # define CONFIG_TELNET_MAXLCLIENTS 8 #endif #ifndef CONFIG_TELNET_IOTHREAD_PRIORITY # define CONFIG_TELNET_IOTHREAD_PRIORITY 100 #endif #ifndef CONFIG_TELNET_IOTHREAD_STACKSIZE # define CONFIG_TELNET_IOTHREAD_STACKSIZE 1024 #endif #undef HAVE_SIGNALS #if defined(CONFIG_TTY_SIGINT) || defined(CONFIG_TTY_SIGSTP) # define HAVE_SIGNALS #endif /* Telnet protocol stuff ****************************************************/ #define TELNET_NL 0x0a #define TELNET_CR 0x0d /* Telnet commands */ #define TELNET_ECHO 1 #define TELNET_SGA 3 /* Suppress Go Ahead */ #define TELNET_NAWS 31 /* Negotiate about window size */ /* Telnet control */ #define TELNET_IAC 255 #define TELNET_WILL 251 #define TELNET_WONT 252 #define TELNET_DO 253 #define TELNET_DONT 254 #define TELNET_SB 250 #define TELNET_SE 240 /* Device stuff *************************************************************/ #define TELNET_DEVFMT "/dev/telnet%d" /**************************************************************************** * Private Types ****************************************************************************/ /* The state of the telnet parser */ enum telnet_state_e { STATE_NORMAL = 0, STATE_IAC, STATE_WILL, STATE_WONT, STATE_DO, STATE_DONT, STATE_SB, STATE_SB_NAWS, STATE_SE }; /* This structure describes the internal state of the driver */ struct telnet_dev_s { sem_t td_exclsem; /* Enforces mutually exclusive access */ sem_t td_iosem; /* I/O thread will notify that data is available */ uint8_t td_state; /* (See telnet_state_e) */ uint8_t td_pending; /* Number of valid, pending bytes in the rxbuffer */ uint8_t td_offset; /* Offset to the valid, pending bytes in the rxbuffer */ uint8_t td_crefs; /* The number of open references to the session */ uint8_t td_minor; /* Minor device number */ #ifdef CONFIG_TELNET_SUPPORT_NAWS uint16_t td_rows; /* Number of NAWS rows */ uint16_t td_cols; /* Number of NAWS cols */ int td_sb_count; /* Count of TELNET_SB bytes received */ #endif #ifdef HAVE_SIGNALS pid_t td_pid; #endif struct pollfd td_fds; FAR struct socket td_psock; /* A clone of the internal socket structure */ char td_rxbuffer[CONFIG_TELNET_RXBUFFER_SIZE]; char td_txbuffer[CONFIG_TELNET_TXBUFFER_SIZE]; }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Support functions */ #ifdef CONFIG_TELNET_DUMPBUFFER static inline void telnet_dumpbuffer(FAR const char *msg, FAR const char *buffer, unsigned int nbytes); #else # define telnet_dumpbuffer(msg,buffer,nbytes) #endif static void telnet_getchar(FAR struct telnet_dev_s *priv, uint8_t ch, FAR char *dest, int *nread); static ssize_t telnet_receive(FAR struct telnet_dev_s *priv, FAR const char *src, size_t srclen, FAR char *dest, size_t destlen); static bool telnet_putchar(FAR struct telnet_dev_s *priv, uint8_t ch, int *nwritten); static void telnet_sendopt(FAR struct telnet_dev_s *priv, uint8_t option, uint8_t value); static int telnet_io_main(int argc, FAR char** argv); /* Telnet character driver methods */ static int telnet_open(FAR struct file *filep); static int telnet_close(FAR struct file *filep); static ssize_t telnet_read(FAR struct file *filep, FAR char *buffer, size_t len); static ssize_t telnet_write(FAR struct file *filep, FAR const char *buffer, size_t len); static int telnet_ioctl(FAR struct file *filep, int cmd, unsigned long arg); static int telnet_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup); /* Telnet session creation */ static int telnet_session(FAR struct telnet_session_s *session); /* Telnet factory driver methods */ static ssize_t factory_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t factory_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int factory_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_telnet_fops = { telnet_open, /* open */ telnet_close, /* close */ telnet_read, /* read */ telnet_write, /* write */ NULL, /* seek */ telnet_ioctl, /* ioctl */ telnet_poll /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL /* unlink */ #endif }; static const struct file_operations g_factory_fops = { NULL, /* open */ NULL, /* close */ factory_read, /* read */ factory_write, /* write */ NULL, /* seek */ factory_ioctl, /* ioctl */ NULL /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , NULL /* unlink */ #endif }; /* This is an global data set of all of all active Telnet drivers. This * additional logic in included to handle killing of task via control * characters received via Telenet (via Ctrl-C SIGINT, in particular). */ static pid_t g_telnet_io_kthread; static struct telnet_dev_s *g_telnet_clients[CONFIG_TELNET_MAXLCLIENTS]; static sem_t g_iosem = SEM_INITIALIZER(0); static sem_t g_clients_sem = SEM_INITIALIZER(1); /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: telnet_dumpbuffer * * Description: * Dump a buffer of data (debug only) * ****************************************************************************/ #ifdef CONFIG_TELNET_DUMPBUFFER static inline void telnet_dumpbuffer(FAR const char *msg, FAR const char *buffer, unsigned int nbytes) { /* CONFIG_DEBUG_FEATURES, CONFIG_DEBUG_INFO, and CONFIG_DEBUG_NET have to * be defined or the following does nothing. */ ninfodumpbuffer(msg, (FAR const uint8_t *)buffer, nbytes); } #endif /**************************************************************************** * Name: telnet_check_ctrlchar * * Description: * Check if an incoming control character should generate a signal. * ****************************************************************************/ #ifdef HAVE_SIGNALS static void telnet_check_ctrlchar(FAR struct telnet_dev_s *priv, FAR char *buffer, size_t len) { int signo = 0; for (; priv->td_pid >= 0 && len > 0; buffer++, len--) { #ifdef CONFIG_TTY_SIGINT /* Is this the special character that will generate the SIGINT signal? */ if (*buffer == CONFIG_TTY_SIGINT_CHAR) { /* Yes.. note that the kill is needed and do not put the character * into the Rx buffer. It should not be read as normal data. */ signo = SIGINT; break; } #endif #ifdef CONFIG_TTY_SIGSTP /* Is this the special character that will generate the SIGSTP signal? */ if (*buffer == CONFIG_TTY_SIGSTP_CHAR) { /* Note that the kill is needed and do not put the character * into the Rx buffer. It should not be read as normal data. */ signo = SIGSTP; #ifndef CONFIG_TTY_SIGINT break; #endif } #endif } /* Send the signal if necessary */ if (signo != 0) { nxsig_kill(priv->td_pid, signo); } } #endif /**************************************************************************** * Name: telnet_getchar * * Description: * Get another character for the user received buffer from the RX buffer * ****************************************************************************/ static void telnet_getchar(FAR struct telnet_dev_s *priv, uint8_t ch, FAR char *dest, int *nread) { register int index; #ifndef CONFIG_TELNET_CHARACTER_MODE /* Ignore carriage returns */ if (ch != TELNET_CR) #endif { /* Add all other characters to the destination buffer */ index = *nread; dest[index++] = ch; *nread = index; } } /**************************************************************************** * Name: telnet_receive * * Description: * Process a received Telnet buffer * ****************************************************************************/ static ssize_t telnet_receive(FAR struct telnet_dev_s *priv, FAR const char *src, size_t srclen, FAR char *dest, size_t destlen) { int nread; uint8_t ch; ninfo("srclen: %d destlen: %d\n", srclen, destlen); for (nread = 0; srclen > 0 && nread < destlen; srclen--) { ch = *src++; ninfo("ch=%02x state=%d\n", ch, priv->td_state); switch (priv->td_state) { case STATE_IAC: if (ch == TELNET_IAC) { telnet_getchar(priv, ch, dest, &nread); priv->td_state = STATE_NORMAL; } else { switch (ch) { case TELNET_WILL: priv->td_state = STATE_WILL; break; case TELNET_WONT: priv->td_state = STATE_WONT; break; case TELNET_DO: priv->td_state = STATE_DO; break; case TELNET_DONT: priv->td_state = STATE_DONT; break; #ifdef CONFIG_TELNET_SUPPORT_NAWS case TELNET_SB: priv->td_state = STATE_SB; priv->td_sb_count = 0; break; case TELNET_SE: priv->td_state = STATE_NORMAL; break; #endif default: priv->td_state = STATE_NORMAL; break; } } break; case STATE_WILL: #ifdef CONFIG_TELNET_SUPPORT_NAWS /* For NAWS, Reply with a DO */ if (ch == TELNET_NAWS) { telnet_sendopt(priv, TELNET_DO, ch); } /* Reply with a DON'T */ else #endif { telnet_sendopt(priv, TELNET_DONT, ch); ninfo("Suppress: 0x%02X (%d)\n", ch, ch); } priv->td_state = STATE_NORMAL; break; case STATE_WONT: telnet_sendopt(priv, TELNET_DONT, ch); priv->td_state = STATE_NORMAL; break; case STATE_DO: #ifdef CONFIG_TELNET_CHARACTER_MODE if (ch == TELNET_SGA || ch == TELNET_ECHO) { /* If it received 'ECHO' or 'Suppress Go Ahead', then do nothing */ } else { /* Reply with a WONT */ telnet_sendopt(priv, TELNET_WONT, ch); ninfo("WONT: 0x%02X\n", ch); } #else /* Reply with a WONT */ telnet_sendopt(priv, TELNET_WONT, ch); #endif priv->td_state = STATE_NORMAL; break; case STATE_DONT: /* Reply with a WONT */ telnet_sendopt(priv, TELNET_WONT, ch); priv->td_state = STATE_NORMAL; break; case STATE_NORMAL: if (ch == TELNET_IAC) { priv->td_state = STATE_IAC; } else { telnet_getchar(priv, ch, dest, &nread); } break; #ifdef CONFIG_TELNET_SUPPORT_NAWS /* Handle Telnet Sub negotiation request */ case STATE_SB: switch (ch) { case TELNET_NAWS: priv->td_state = STATE_SB_NAWS; break; default: priv->td_state = STATE_NORMAL; break; } break; /* Handle NAWS sub-option negotiation */ case STATE_SB_NAWS: /* Update cols / rows based on received byte count */ switch (priv->td_sb_count) { case 0: priv->td_cols = (priv->td_cols & 0x00ff) | (ch << 8); break; case 1: priv->td_cols = (priv->td_cols & 0xff00) | ch; break; case 2: priv->td_rows = (priv->td_rows & 0x00ff) | (ch << 8); break; case 3: priv->td_rows = (priv->td_rows & 0xff00) | ch; ninfo("NAWS: %d,%d", priv->td_cols, priv->td_rows); break; } /* Increment SB count and switch to NORMAL when complete */ if (++priv->td_sb_count == 4) { priv->td_state = STATE_NORMAL; } break; #endif } } /* We get here if (1) all of the received bytes have been processed, or * (2) if the user's buffer has become full. */ if (srclen > 0) { /* Remember where we left off. These bytes will be returned the next * time that telnet_read() is called. */ priv->td_pending = srclen; priv->td_offset = (src - priv->td_rxbuffer); } else { /* All of the received bytes were consumed */ priv->td_pending = 0; priv->td_offset = 0; } return nread; } /**************************************************************************** * Name: telnet_putchar * * Description: * Put another character from the user buffer to the TX buffer. * ****************************************************************************/ static bool telnet_putchar(FAR struct telnet_dev_s *priv, uint8_t ch, int *nread) { register int index; bool ret = false; /* Ignore carriage returns (we will put these in automatically as necessary) */ if (ch != TELNET_CR) { /* Add all other characters to the destination buffer */ index = *nread; priv->td_txbuffer[index++] = ch; /* Check for line feeds */ if (ch == TELNET_NL) { /* Now add the carriage return */ priv->td_txbuffer[index++] = TELNET_CR; /* End of line */ ret = true; } *nread = index; } return ret; } /**************************************************************************** * Name: telnet_sendopt * * Description: * Send the telnet option bytes * ****************************************************************************/ static void telnet_sendopt(FAR struct telnet_dev_s *priv, uint8_t option, uint8_t value) { uint8_t optbuf[3]; int ret; optbuf[0] = TELNET_IAC; optbuf[1] = option; optbuf[2] = value; telnet_dumpbuffer("Send optbuf", optbuf, 3); ret = psock_send(&priv->td_psock, optbuf, 3, 0); if (ret < 0) { nerr("ERROR: Failed to send TELNET_IAC: %d\n", ret); } } /**************************************************************************** * Name: telnet_open ****************************************************************************/ static int telnet_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct telnet_dev_s *priv = inode->i_private; int tmp; int ret; ninfo("td_crefs: %d\n", priv->td_crefs); /* Get exclusive access to the device structures */ ret = nxsem_wait(&priv->td_exclsem); if (ret < 0) { nerr("ERROR: nxsem_wait failed: %d\n", ret); goto errout; } /* Increment the count of references to the device. If this the first * time that the driver has been opened for this device, then initialize * the device. */ tmp = priv->td_crefs + 1; if (tmp > 255) { /* More than 255 opens; uint8_t would overflow to zero */ ret = -EMFILE; goto errout_with_sem; } /* Save the new open count on success */ priv->td_crefs = tmp; ret = OK; errout_with_sem: nxsem_post(&priv->td_exclsem); errout: return ret; } /**************************************************************************** * Name: telnet_close ****************************************************************************/ static int telnet_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct telnet_dev_s *priv = inode->i_private; FAR char *devpath; int ret; int i; ninfo("td_crefs: %d\n", priv->td_crefs); /* Get exclusive access to the device structures */ ret = nxsem_wait(&priv->td_exclsem); if (ret < 0) { nerr("ERROR: nxsem_wait failed: %d\n", ret); goto errout; } /* Decrement the references to the driver. If the reference count will * decrement to 0, then uninitialize the driver. */ if (priv->td_crefs > 1) { /* Just decrement the reference count and release the semaphore */ priv->td_crefs--; nxsem_post(&priv->td_exclsem); } else { /* Re-create the path to the driver. */ ret = asprintf(&devpath, TELNET_DEVFMT, priv->td_minor); if (ret < 0) { nerr("ERROR: Failed to allocate the driver path\n"); } else { /* Un-register the character driver */ ret = unregister_driver(devpath); if (ret < 0) { /* NOTE: a return value of -EBUSY is not an error, it simply * means that the Telnet driver is busy now and cannot be * registered now because there are other sessions using the * connection. The driver will be properly unregistered when * the final session terminates. */ if (ret != -EBUSY) { nerr("ERROR: Failed to unregister the driver %s: %d\n", devpath, ret); } else { ret = OK; } } kmm_free(devpath); } /* Remove ourself from the clients list */ nxsem_wait(&g_clients_sem); for (i = 0; i < CONFIG_TELNET_MAXLCLIENTS; i++) { if (g_telnet_clients[i] == priv) { g_telnet_clients[i] = NULL; break; } } /* If the socket is still polling */ if (priv->td_fds.events) { /* Tear down the poll */ psock_poll(&priv->td_psock, &priv->td_fds, FALSE); priv->td_fds.events = 0; } nxsem_post(&g_clients_sem); /* Notify the I/O thread that a client was removed */ nxsem_post(&g_iosem); /* Close the socket */ psock_close(&priv->td_psock); /* Release the driver memory. What if there are threads waiting on * td_exclsem? They will never be awakened! How could this happen? * crefs == 1 so there are no other open references to the driver. * But this could have if someone were trying to re-open the driver * after every other thread has closed it. That really should not * happen in the intended usage model. */ DEBUGASSERT(priv->td_exclsem.semcount == 0); nxsem_destroy(&priv->td_exclsem); kmm_free(priv); } errout: return ret; } /**************************************************************************** * Name: telnet_read ****************************************************************************/ static ssize_t telnet_read(FAR struct file *filep, FAR char *buffer, size_t len) { FAR struct inode *inode = filep->f_inode; FAR struct telnet_dev_s *priv = inode->i_private; ssize_t ret = 0; ninfo("len: %d\n", len); /* First, handle the case where there are still valid bytes left in the * I/O buffer from the last time that read was called. NOTE: Much of * what we read may be protocol stuff and may not correspond to user * data. Hence we need the loop and we need may need to wait for data * multiple times in order to get data that the client is interested in. */ do { FAR const char *src; if (priv->td_pending == 0) { /* poll fds.revents contains last poll status in case of error */ if ((priv->td_fds.revents & (POLLHUP | POLLERR)) != 0) { return -EPIPE; } if (filep->f_oflags & O_NONBLOCK) { return -EAGAIN; } /* Wait for new data (or error) */ nxsem_wait_uninterruptible(&priv->td_iosem); continue; } /* Take exclusive access to data buffer */ nxsem_wait(&priv->td_exclsem); /* Process the buffered telnet data */ src = &priv->td_rxbuffer[priv->td_offset]; ret = telnet_receive(priv, src, priv->td_pending, buffer, len); nxsem_post(&priv->td_exclsem); } while (ret == 0); /* Returned Value: * * ret > 0: The number of characters copied into the user buffer by * telnet_receive(). * ret <= 0: Loss of connection or error events reported by recv(). */ return ret; } /**************************************************************************** * Name: telnet_write ****************************************************************************/ static ssize_t telnet_write(FAR struct file *filep, FAR const char *buffer, size_t len) { FAR struct inode *inode = filep->f_inode; FAR struct telnet_dev_s *priv = inode->i_private; FAR const char *src = buffer; ssize_t nsent; ssize_t ret; int ncopied; char ch; bool eol; ninfo("len: %d\n", len); /* Process each character from the user buffer */ for (nsent = 0, ncopied = 0; nsent < len; nsent++) { /* Get the next character from the user buffer */ ch = *src++; /* Add the character to the TX buffer */ eol = telnet_putchar(priv, ch, &ncopied); /* Was that the end of a line? Or is the buffer too full to hold the * next largest character sequence ("\r\n")? */ if (eol || ncopied > CONFIG_TELNET_TXBUFFER_SIZE - 2) { /* Yes... send the data now */ ret = psock_send(&priv->td_psock, priv->td_txbuffer, ncopied, 0); if (ret < 0) { nerr("ERROR: psock_send failed '%s': %d\n", priv->td_txbuffer, ret); return ret; } /* Reset the index to the beginning of the TX buffer. */ ncopied = 0; } } /* Send anything remaining in the TX buffer */ if (ncopied > 0) { ret = psock_send(&priv->td_psock, priv->td_txbuffer, ncopied, 0); if (ret < 0) { nerr("ERROR: psock_send failed '%s': %d\n", priv->td_txbuffer, ret); return ret; } } /* Notice that we don't actually return the number of bytes sent, but * rather, the number of bytes that the caller asked us to send. We may * have sent more bytes (because of CR-LF expansion). But it confuses * some logic if you report that you sent more than you were requested to. */ return len; } /**************************************************************************** * Name: telnet_session * * Description: * Create a character driver to "wrap" the telnet session. This function * will select and return a unique path for the new telnet device. * * Input Parameters: * session - On input, contains the socket descriptor that represents the * new telnet connection. On output, it holds the path to the new Telnet * driver. * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ static int telnet_session(FAR struct telnet_session_s *session) { FAR struct telnet_dev_s *priv; FAR struct socket *psock; int ret; /* Allocate instance data for this driver */ priv = (FAR struct telnet_dev_s *)kmm_zalloc(sizeof(struct telnet_dev_s)); if (!priv) { nerr("ERROR: Failed to allocate the driver data structure\n"); return -ENOMEM; } /* Initialize the allocated driver instance */ nxsem_init(&priv->td_exclsem, 0, 1); nxsem_init(&priv->td_iosem, 0, 0); /* td_iosem is used for signaling and, hence, must not participate in * priority inheritance. */ nxsem_setprotocol(&priv->td_iosem, SEM_PRIO_NONE); priv->td_state = STATE_NORMAL; priv->td_crefs = 0; priv->td_minor = 0; priv->td_pending = 0; priv->td_offset = 0; #ifdef HAVE_SIGNALS priv->td_pid = -1; #endif #ifdef CONFIG_TELNET_SUPPORT_NAWS priv->td_rows = 25; priv->td_cols = 80; priv->td_sb_count = 0; #endif /* Clone the internal socket structure. We do this so that it will be * independent of threads and of socket descriptors (the original socket * instance resided in the daemon's task group`). */ psock = sockfd_socket(session->ts_sd); if (!psock) { nerr("ERROR: Failed to convert sd=%d to a socket structure\n", session->ts_sd); ret = -EINVAL; goto errout_with_dev; } ret = psock_dup2(psock, &priv->td_psock); if (ret < 0) { nerr("ERROR: psock_dup2 failed: %d\n", ret); goto errout_with_dev; } /* Allocate a unique minor device number of the telnet driver. * Get exclusive access to the minor counter. */ ret = nxsem_wait_uninterruptible(&g_clients_sem); if (ret < 0) { nerr("ERROR: nxsem_wait failed: %d\n", ret); goto errout_with_clone; } /* Loop until the device name is verified to be unique. */ while (priv->td_minor < CONFIG_TELNET_MAXLCLIENTS) { if (g_telnet_clients[priv->td_minor] == NULL) { snprintf(session->ts_devpath, TELNET_DEVPATH_MAX, TELNET_DEVFMT, priv->td_minor); break; } priv->td_minor++; } if (priv->td_minor >= CONFIG_TELNET_MAXLCLIENTS) { nerr("ERROR: Too many sessions\n"); ret = -ENFILE; goto errout_with_semaphore; } /* Register the driver */ ret = register_driver(session->ts_devpath, &g_telnet_fops, 0666, priv); if (ret < 0) { nerr("ERROR: Failed to register the driver %s: %d\n", session->ts_devpath, ret); goto errout_with_semaphore; } /* Close the original psoock (keeping the clone) */ psock_close(psock); #ifdef CONFIG_TELNET_SUPPORT_NAWS telnet_sendopt(priv, TELNET_DO, TELNET_NAWS); #endif #ifdef CONFIG_TELNET_CHARACTER_MODE telnet_sendopt(priv, TELNET_WILL, TELNET_SGA); telnet_sendopt(priv, TELNET_WILL, TELNET_ECHO); #endif /* Has the I/O thread been started? */ if (g_telnet_io_kthread == (pid_t)0) { /* g_iosem is used for signaling and, hence, must not participate in * priority inheritance. */ nxsem_setprotocol(&g_iosem, SEM_PRIO_NONE); /* Start the I/O thread */ g_telnet_io_kthread = kthread_create("telnet_io", CONFIG_TELNET_IOTHREAD_PRIORITY, CONFIG_TELNET_IOTHREAD_STACKSIZE, telnet_io_main, NULL); } /* Save ourself in the list of Telnet client threads */ g_telnet_clients[priv->td_minor] = priv; nxsem_post(&g_clients_sem); nxsem_post(&g_iosem); return OK; errout_with_semaphore: nxsem_post(&g_clients_sem); errout_with_clone: psock_close(&priv->td_psock); errout_with_dev: free(priv); return ret; } /**************************************************************************** * Name: factory_read ****************************************************************************/ static ssize_t factory_read(FAR struct file *filep, FAR char *buffer, size_t len) { return 0; /* Return EOF */ } /**************************************************************************** * Name: factory_write ****************************************************************************/ static ssize_t factory_write(FAR struct file *filep, FAR const char *buffer, size_t len) { return len; /* Say that everything was written */ } /**************************************************************************** * Name: telnet_ioctl ****************************************************************************/ static int telnet_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR struct telnet_dev_s *priv = inode->i_private; int ret = OK; switch (cmd) { #ifdef HAVE_SIGNALS /* Make the given terminal the controlling terminal of the calling process */ case TIOCSCTTY: { /* Check if the ISIG flag is set in the termios c_lflag to enable * this feature. This flag is set automatically for a serial console * device. */ /* Save the PID of the recipient of the SIGINT signal. */ priv->td_pid = (pid_t)arg; DEBUGASSERT((unsigned long)(priv->td_pid) == arg); } break; #endif #ifdef CONFIG_TELNET_SUPPORT_NAWS case TIOCGWINSZ: { FAR struct winsize *pw = (FAR struct winsize *)((uintptr_t)arg); /* Get row/col from the private data */ pw->ws_row = priv->td_rows; pw->ws_col = priv->td_cols; } break; #endif default: ret = -ENOTTY; break; } UNUSED(priv); /* Avoid warning if not used */ return ret; } /**************************************************************************** * Name: telnet_poll * * Description: * The standard poll() operation redirects operations on socket descriptors * to this function. * * Input Parameters: * fd - The socket descriptor of interest * fds - The structure describing the events to be monitored, OR NULL if * this is a request to stop monitoring events. * setup - true: Setup up the poll; false: Teardown the poll * * Returned Value: * 0: Success; Negated errno on failure * ****************************************************************************/ static int telnet_poll(FAR struct file *filep, FAR struct pollfd *fds, bool setup) { FAR struct inode *inode = filep->f_inode; FAR struct telnet_dev_s *priv = inode->i_private; FAR struct socket *psock; DEBUGASSERT(fds != NULL); /* Get the underlying socket structure and verify that the sockfd * corresponds to valid, allocated socket */ psock = &priv->td_psock; if (!psock || psock->s_crefs <= 0) { return -EBADF; } /* Test if we have cached data waiting to be read */ if (priv->td_pending > 0) { /* Yes.. then signal the poll logic */ fds->revents |= (POLLRDNORM & fds->events); if (fds->revents) { nxsem_post(fds->sem); } } /* Then let psock_poll() do the heavy lifting */ return psock_poll(psock, fds, setup); } /**************************************************************************** * Name: telnet_io_main ****************************************************************************/ static int telnet_io_main(int argc, FAR char** argv) { FAR struct telnet_dev_s *priv; FAR char *buffer; int i; int ret; while (1) { nxsem_reset(&g_iosem, 0); /* Poll each client in the g_telnet_clients[] array. */ nxsem_wait(&g_clients_sem); for (i = 0; i < CONFIG_TELNET_MAXLCLIENTS; i++) { priv = g_telnet_clients[i]; if (priv != NULL && !(priv->td_fds.revents & (POLLHUP | POLLERR))) { priv->td_fds.sem = &g_iosem; priv->td_fds.events = POLLIN | POLLHUP | POLLERR; priv->td_fds.revents = 0; psock_poll(&priv->td_psock, &priv->td_fds, TRUE); } } nxsem_post(&g_clients_sem); /* Wait for any Telnet connect/disconnect events * to include/remove client sockets from polling */ nxsem_wait(&g_iosem); /* Revisit each client in the g_telnet_clients[] array */ nxsem_wait(&g_clients_sem); for (i = 0; i < CONFIG_TELNET_MAXLCLIENTS; i++) { priv = g_telnet_clients[i]; /* If poll was setup previously (events != 0) */ if (priv != NULL && priv->td_fds.events) { /* Check for a pending poll() */ if (priv->td_fds.revents & POLLIN) { if (priv->td_pending < CONFIG_TELNET_RXBUFFER_SIZE) { /* Take exclusive access to data buffer */ nxsem_wait(&priv->td_exclsem); buffer = priv->td_rxbuffer + priv->td_pending + priv->td_offset; ret = psock_recv(&priv->td_psock, buffer, CONFIG_TELNET_RXBUFFER_SIZE - priv->td_pending - priv->td_offset, 0); priv->td_pending += ret; nxsem_post(&priv->td_exclsem); /* Notify the client thread that data is available */ nxsem_post(&priv->td_iosem); #ifdef HAVE_SIGNALS /* Check if any of the received characters is a * control that should generate a signal. */ telnet_check_ctrlchar(priv, buffer, ret); #endif } } /* Tear it down */ psock_poll(&priv->td_psock, &priv->td_fds, FALSE); priv->td_fds.events = 0; /* POLLHUP (or POLLERR) indicates that this session has * terminated. */ if (priv->td_fds.revents & (POLLHUP | POLLERR)) { /* notify the client thread */ nxsem_post(&priv->td_iosem); } } } nxsem_post(&g_clients_sem); } return 0; } /**************************************************************************** * Name: factory_ioctl ****************************************************************************/ static int factory_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { int ret = OK; switch (cmd) { /* Command: SIOCTELNET * Description: Create a Telnet sessions. * Argument: A pointer to a write-able instance of struct * telnet_session_s. * Dependencies: CONFIG_NETDEV_TELNET */ case SIOCTELNET: { FAR struct telnet_session_s *session = (FAR struct telnet_session_s *)((uintptr_t)arg); if (session == NULL) { ret = -EINVAL; } else { ret = telnet_session(session); } } break; default: ret = -ENOTTY; break; } return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: telnet_initialize * * Description: * Create the Telnet factory at /dev/telnet. * * Input Parameters: * None * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int telnet_initialize(void) { return register_driver("/dev/telnet", &g_factory_fops, 0666, NULL); } #endif /* CONFIG_NETDEV_TELNET */