AP_Networking: added SLIP support

libraries/AP_Networking/AP_Networking.cpp

@@ -14,6 +14,7 @@ extern const AP_HAL::HAL& hal;
 
 #if AP_NETWORKING_BACKEND_CHIBIOS
 #include "AP_Networking_ChibiOS.h"
+#include "AP_Networking_SLIP.h"
 #include <hal_mii.h>
 #include <lwip/sockets.h>
 #else
@@ -22,6 +23,10 @@ extern const AP_HAL::HAL& hal;
 
 #include <AP_HAL/utility/Socket.h>
 
+#if AP_NETWORKING_BACKEND_SLIP
+#include "AP_Networking_SLIP.h"
+#endif
+
 #if AP_NETWORKING_BACKEND_SITL
 #include "AP_Networking_SITL.h"
 #endif
@@ -124,11 +129,21 @@ void AP_Networking::init()
     }
 #endif
 
+#if AP_NETWORKING_BACKEND_SLIP
+    if (AP::serialmanager().have_serial(AP_SerialManager::SerialProtocol_SLIP, 0)) {
+        backend = new AP_Networking_SLIP(*this);
+    }
+#endif
+
 #if AP_NETWORKING_BACKEND_CHIBIOS
-    backend = new AP_Networking_ChibiOS(*this);
+    if (backend == nullptr) {
+        backend = new AP_Networking_ChibiOS(*this);
+    }
 #endif
 #if AP_NETWORKING_BACKEND_SITL
-    backend = new AP_Networking_SITL(*this);
+    if (backend == nullptr) {
+        backend = new AP_Networking_SITL(*this);
+    }
 #endif
 
     if (backend == nullptr) {
@@ -374,15 +389,16 @@ AP_Networking &network()
  */
 int ap_networking_printf(const char *fmt, ...)
 {
-#ifdef AP_NETWORKING_LWIP_DEBUG_PORT
+#if AP_NETWORKING_LWIP_DEBUG_PORT >= 0
     static AP_HAL::UARTDriver *uart;
     if (uart == nullptr) {
         uart = hal.serial(AP_NETWORKING_LWIP_DEBUG_PORT);
         if (uart == nullptr) {
             return -1;
         }
-        uart->begin(921600, 0, 50000);
+        uart->begin(AP_NETWORKING_LWIP_DEBUG_BAUD, 1000, 50000);
     }
+    uart->begin(0);
     va_list ap;
     va_start(ap, fmt);
     uart->vprintf(fmt, ap);

libraries/AP_Networking/AP_Networking_Backend.h

@@ -19,7 +19,7 @@ public:
     CLASS_NO_COPY(AP_Networking_Backend);
 
     virtual bool init() = 0;
-    virtual void update() = 0;
+    virtual void update() {};
 
 protected:
     AP_Networking &frontend;

libraries/AP_Networking/AP_Networking_Config.h

@@ -22,6 +22,11 @@
 // ---------------------------
 #ifndef AP_NETWORKING_BACKEND_CHIBIOS
 #define AP_NETWORKING_BACKEND_CHIBIOS (AP_NETWORKING_BACKEND_DEFAULT_ENABLED && (CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS))
+#define AP_NETWORKING_BACKEND_SLIP (AP_NETWORKING_BACKEND_DEFAULT_ENABLED && (CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS))
+#endif
+
+#ifndef AP_NETWORKING_BACKEND_SLIP
+#define AP_NETWORKING_BACKEND_SLIP (AP_NETWORKING_BACKEND_DEFAULT_ENABLED && (CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS))
 #endif
 
 #ifndef AP_NETWORKING_BACKEND_SITL

libraries/AP_Networking/AP_Networking_SITL.h

@@ -16,7 +16,6 @@ public:
     bool init() override {
         return true;
     }
-    void update() override {}
 };
 
 #endif // AP_NETWORKING_BACKEND_SITL

libraries/AP_Networking/AP_Networking_SLIP.cpp

@@ -0,0 +1,99 @@
+
+#include "AP_Networking_Config.h"
+
+#if AP_NETWORKING_BACKEND_SLIP
+
+#include "AP_Networking_SLIP.h"
+#include <GCS_MAVLink/GCS.h>
+
+#include <lwipthread.h>
+#include <lwip/udp.h>
+#include <lwip/ip_addr.h>
+#include <lwip/sio.h>
+#include <lwip/tcpip.h>
+
+#include <netif/slipif.h>
+
+extern const AP_HAL::HAL& hal;
+AP_HAL::UARTDriver *AP_Networking_SLIP::uart;
+
+/*
+  initialise SLIP network backend using LWIP
+ */
+bool AP_Networking_SLIP::init()
+{
+    uart = AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_SLIP, 0);
+    if (uart == nullptr) {
+        return false;
+    }
+    uart->set_unbuffered_writes(true);
+    
+    slipif = new netif;
+    if (slipif == nullptr) {
+        return false;
+    }
+
+    // no dynamic IPs for SLIP
+    activeSettings.ip = frontend.get_ip_param();
+    activeSettings.gw = frontend.get_gateway_param();
+    activeSettings.nm = frontend.get_netmask_param();
+    activeSettings.last_change_ms = AP_HAL::millis();
+    
+    const ip4_addr_t ipaddr {htonl(activeSettings.ip)};
+    const ip4_addr_t netmask {htonl(activeSettings.nm)};
+    const ip4_addr_t gw {htonl(activeSettings.gw)};
+
+    tcpip_init(NULL, NULL);
+    hal.scheduler->delay(100);
+    
+    netif_add(slipif,
+              &ipaddr, &netmask, &gw,
+              &num_slip, slipif_init, ip_input);
+    netif_set_default(slipif);
+    slipif->mtu = 296;
+    netif_set_link_up(slipif);
+    netif_set_up(slipif);
+    
+    hal.scheduler->thread_create(FUNCTOR_BIND_MEMBER(&AP_Networking_SLIP::slip_loop, void),
+                                 "slip",
+                                 8192, AP_HAL::Scheduler::PRIORITY_UART, -1);
+    
+    return true;
+}
+
+/*
+  main loop for SLIP
+ */
+void AP_Networking_SLIP::slip_loop(void)
+{
+    uart->begin(0);
+    hal.scheduler->delay(100);
+    while (true) {
+        slipif_poll(slipif);
+        hal.scheduler->delay_microseconds(100);
+    }
+}
+
+void sio_send(uint8_t c, void *fd)
+{
+    auto *uart = (AP_HAL::UARTDriver *)fd;
+    uart->write(c);
+}
+
+sio_fd_t sio_open(uint8_t dev)
+{
+    return AP_Networking_SLIP::uart;
+}
+
+u32_t sio_tryread(sio_fd_t fd, u8_t *data, u32_t len)
+{
+    auto *uart = (AP_HAL::UARTDriver *)fd;
+    uart->begin(0);
+    const auto ret = uart->read(data, len);
+    if (ret <= 0) {
+        return 0;
+    }
+    return ret;
+}
+
+#endif // AP_NETWORKING_BACKEND_SLIP

libraries/AP_Networking/AP_Networking_SLIP.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "AP_Networking_Config.h"
+
+#ifdef AP_NETWORKING_BACKEND_SLIP
+#include "AP_Networking_Backend.h"
+
+class AP_Networking_SLIP : public AP_Networking_Backend
+{
+public:
+    using AP_Networking_Backend::AP_Networking_Backend;
+
+    /* Do not allow copies */
+    CLASS_NO_COPY(AP_Networking_SLIP);
+
+    bool init() override;
+
+    static AP_HAL::UARTDriver *uart;
+    
+private:
+    void slip_loop(void);
+
+    struct netif *slipif;
+    uint8_t num_slip;
+};
+
+#endif // AP_NETWORKING_BACKEND_SLIP