AP_Networking: added PPP support

libraries/AP_Networking/AP_Networking.cpp

@@ -15,6 +15,7 @@ extern const AP_HAL::HAL& hal;
 #if AP_NETWORKING_BACKEND_CHIBIOS
 #include "AP_Networking_ChibiOS.h"
 #include "AP_Networking_SLIP.h"
+#include "AP_Networking_PPP.h"
 #include <hal_mii.h>
 #include <lwip/sockets.h>
 #else
@@ -27,6 +28,10 @@ extern const AP_HAL::HAL& hal;
 #include "AP_Networking_SLIP.h"
 #endif
 
+#if AP_NETWORKING_BACKEND_PPP
+#include "AP_Networking_PPP.h"
+#endif
+
 #if AP_NETWORKING_BACKEND_SITL
 #include "AP_Networking_SITL.h"
 #endif
@@ -129,8 +134,14 @@ void AP_Networking::init()
     }
 #endif
 
+#if AP_NETWORKING_BACKEND_PPP
+    if (AP::serialmanager().have_serial(AP_SerialManager::SerialProtocol_PPP, 0)) {
+        backend = new AP_Networking_PPP(*this);
+    }
+#endif
+
 #if AP_NETWORKING_BACKEND_SLIP
-    if (AP::serialmanager().have_serial(AP_SerialManager::SerialProtocol_SLIP, 0)) {
+    if (backend == nullptr && AP::serialmanager().have_serial(AP_SerialManager::SerialProtocol_SLIP, 0)) {
         backend = new AP_Networking_SLIP(*this);
     }
 #endif

libraries/AP_Networking/AP_Networking_Config.h

@@ -22,7 +22,10 @@
 // ---------------------------
 #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_PPP
+#define AP_NETWORKING_BACKEND_PPP (AP_NETWORKING_BACKEND_DEFAULT_ENABLED && (CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS))
 #endif
 
 #ifndef AP_NETWORKING_BACKEND_SLIP

libraries/AP_Networking/AP_Networking_PPP.cpp

@@ -0,0 +1,181 @@
+
+#include "AP_Networking_Config.h"
+
+#if AP_NETWORKING_BACKEND_PPP
+
+#include "AP_Networking_PPP.h"
+#include <GCS_MAVLink/GCS.h>
+
+#include <lwipthread.h>
+#include <lwip/udp.h>
+#include <lwip/ip_addr.h>
+#include <netif/ppp/ppp_opts.h>
+#include <netif/ppp/pppapi.h>
+#include <netif/ppp/pppos.h>
+#include <lwip/tcpip.h>
+
+
+extern const AP_HAL::HAL& hal;
+
+/*
+  uint32_t timestamp in smallest available units
+ */
+uint32_t sys_jiffies(void)
+{
+    return AP_HAL::micros();
+}
+
+/*
+  output some data to the uart
+ */
+uint32_t AP_Networking_PPP::ppp_output_cb(ppp_pcb *pcb, const void *data, uint32_t len, void *ctx)
+{
+    auto &driver = *(AP_Networking_PPP *)ctx;
+    LWIP_UNUSED_ARG(pcb);
+    uint32_t remaining = len;
+    uint8_t *ptr = const_cast<uint8_t*>((const uint8_t *)data);
+    while (remaining > 0) {
+        auto n = driver.uart->write(ptr, remaining);
+        if (n > 0) {
+            remaining -= n;
+            ptr += n;
+        } else {
+            hal.scheduler->delay_microseconds(100);
+        }
+    }
+    return len;
+}
+
+/*
+  callback on link status change
+ */
+void AP_Networking_PPP::ppp_status_callback(struct ppp_pcb_s *pcb, int code, void *ctx)
+{
+    auto &driver = *(AP_Networking_PPP *)ctx;
+    struct netif *pppif = ppp_netif(pcb);
+    const char *msg = nullptr;
+
+    switch (code) {
+    case PPPERR_NONE: {
+        // got addresses
+        driver.activeSettings.ip = ntohl(netif_ip4_addr(pppif)->addr);
+        driver.activeSettings.gw = ntohl(netif_ip4_gw(pppif)->addr);
+        driver.activeSettings.nm = ntohl(netif_ip4_netmask(pppif)->addr);
+        driver.activeSettings.last_change_ms = AP_HAL::millis();
+
+        break;
+    }
+    case PPPERR_PARAM: {           /* Invalid parameter. */
+        msg = "PPPERR_PARAM";
+        break;
+    }
+    case PPPERR_OPEN: {            /* Unable to open PPP session. */
+        msg = "PPPERR_OPEN";
+        break;
+    }
+    case PPPERR_DEVICE: {          /* Invalid I/O device for PPP. */
+        msg = "PPPERR_DEVICE";
+        break;
+    }
+    case PPPERR_ALLOC: {           /* Unable to allocate resources. */
+        msg = "PPPERR_ALLOC";
+        break;
+    }
+    case PPPERR_USER: {            /* User interrupt. */
+        msg = "PPPERR_USER";
+        break;
+    }
+    case PPPERR_CONNECT: {         /* Connection lost. */
+        msg = "PPPERR_CONNECT";
+        break;
+    }
+    case PPPERR_AUTHFAIL: {        /* Failed authentication challenge. */
+        msg = "PPPERR_AUTHFAIL";
+        break;
+    }
+    case PPPERR_PROTOCOL: {        /* Failed to meet protocol. */
+        msg = "PPPERR_PROTOCOL";
+        break;
+    }
+    case PPPERR_PEERDEAD: {        /* Connection timeout */
+        msg = "PPPERR_PEERDEAD";
+        break;
+    }
+    case PPPERR_IDLETIMEOUT: {     /* Idle Timeout */
+        msg = "PPPERR_IDLETIMEOUT";
+        break;
+    }
+    case PPPERR_CONNECTTIME: {     /* Max connect time reached */
+        msg = "PPPERR_CONNECTTIME";
+        break;
+    }
+    case PPPERR_LOOPBACK: {        /* Loopback detected */
+        msg = "PPPERR_LOOPBACK";
+        break;
+    }
+    }
+    if (msg != nullptr) {
+        GCS_SEND_TEXT(MAV_SEVERITY_INFO, "PPP: %s", msg);
+    }
+}
+
+
+/*
+  initialise PPP network backend using LWIP
+ */
+bool AP_Networking_PPP::init()
+{
+    uart = AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_PPP, 0);
+    if (uart == nullptr) {
+        return false;
+    }
+    uart->set_unbuffered_writes(true);
+    
+    pppif = new netif;
+    if (pppif == nullptr) {
+        return false;
+    }
+
+    // initialise TCP/IP thread
+    tcpip_init(NULL, NULL);
+    hal.scheduler->delay(100);
+    
+    // create ppp connection
+    ppp = pppos_create(pppif, ppp_output_cb, ppp_status_callback, this);
+    if (ppp == nullptr) {
+        GCS_SEND_TEXT(MAV_SEVERITY_INFO, "PPP: failed to create link");
+        return false;
+    }
+
+    // connect and set as default route
+    ppp_connect(ppp, 0);
+    netif_set_default(pppif);
+
+    GCS_SEND_TEXT(MAV_SEVERITY_INFO, "PPP: started");
+    hal.scheduler->thread_create(FUNCTOR_BIND_MEMBER(&AP_Networking_PPP::ppp_loop, void),
+                                 "ppp",
+                                 8192, AP_HAL::Scheduler::PRIORITY_UART, 0);
+
+    return true;
+}
+
+/*
+  main loop for PPP
+ */
+void AP_Networking_PPP::ppp_loop(void)
+{
+    // ensure this thread owns the uart
+    uart->begin(0);
+
+    while (true) {
+        uint8_t buf[1024];
+        auto n = uart->read(buf, sizeof(buf));
+        if (n > 0) {
+            pppos_input(ppp, buf, n);
+        } else {
+            hal.scheduler->delay_microseconds(100);
+        }
+    }
+}
+
+#endif // AP_NETWORKING_BACKEND_PPP

libraries/AP_Networking/AP_Networking_PPP.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "AP_Networking_Config.h"
+
+#ifdef AP_NETWORKING_BACKEND_PPP
+#include "AP_Networking_Backend.h"
+
+class AP_Networking_PPP : public AP_Networking_Backend
+{
+public:
+    using AP_Networking_Backend::AP_Networking_Backend;
+
+    /* Do not allow copies */
+    CLASS_NO_COPY(AP_Networking_PPP);
+
+    bool init() override;
+
+private:
+    void ppp_loop(void);
+
+    AP_HAL::UARTDriver *uart;
+    struct netif *pppif;
+    struct ppp_pcb_s *ppp;
+
+    static void ppp_status_callback(struct ppp_pcb_s *pcb, int code, void *ctx);
+    static uint32_t ppp_output_cb(struct ppp_pcb_s *pcb, const void *data, uint32_t len, void *ctx);
+};
+
+#endif // AP_NETWORKING_BACKEND_PPP