AP_Networking: added sendfile()

this allows for scripting to offload a file send to the AP_Networking
library, reducing CPU costs of large file downloads

libraries/AP_Networking/AP_Networking.cpp

@@ -8,6 +8,7 @@
 #include <GCS_MAVLink/GCS.h>
 #include <AP_Math/crc.h>
 #include <AP_InternalError/AP_InternalError.h>
+#include <AP_Filesystem/AP_Filesystem.h>
 
 extern const AP_HAL::HAL& hal;
 
@@ -19,6 +20,8 @@ extern const AP_HAL::HAL& hal;
 #include <arpa/inet.h>
 #endif
 
+#include <AP_HAL/utility/Socket.h>
+
 #if AP_NETWORKING_BACKEND_SITL
 #include "AP_Networking_SITL.h"
 #endif
@@ -150,6 +153,9 @@ void AP_Networking::init()
 
     // init network mapped serialmanager ports
     ports_init();
+
+    // register sendfile handler
+    hal.scheduler->register_io_process(FUNCTOR_BIND_MEMBER(&AP_Networking::sendfile_check, void));
 }
 
 /*
@@ -282,6 +288,77 @@ void AP_Networking::startup_wait(void) const
 #endif
 }
 
+/*
+  send the rest of a file to a socket
+ */
+bool AP_Networking::sendfile(SocketAPM *sock, int fd)
+{
+    WITH_SEMAPHORE(sem);
+    if (sendfile_buf == nullptr) {
+        sendfile_buf = (uint8_t *)malloc(AP_NETWORKING_SENDFILE_BUFSIZE);
+        if (sendfile_buf == nullptr) {
+            return false;
+        }
+    }
+    for (auto &s : sendfiles) {
+        if (s.sock == nullptr) {
+            s.sock = sock->duplicate();
+            if (s.sock == nullptr) {
+                return false;
+            }
+            s.fd = fd;
+            return true;
+        }
+    }
+    return false;
+}
+
+void AP_Networking::SendFile::close(void)
+{
+    AP::FS().close(fd);
+    delete sock;
+    sock = nullptr;
+}
+
+#include <stdio.h>
+/*
+  check for sendfile updates
+ */
+void AP_Networking::sendfile_check(void)
+{
+    if (sendfile_buf == nullptr) {
+        return;
+    }
+    WITH_SEMAPHORE(sem);
+    bool none_active = true;
+    for (auto &s : sendfiles) {
+        if (s.sock == nullptr) {
+            continue;
+        }
+        none_active = false;
+        if (!s.sock->pollout(0)) {
+            continue;
+        }
+        const auto nread = AP::FS().read(s.fd, sendfile_buf, AP_NETWORKING_SENDFILE_BUFSIZE);
+        if (nread <= 0) {
+            s.close();
+            continue;
+        }
+        const auto nsent = s.sock->send(sendfile_buf, nread);
+        if (nsent <= 0) {
+            s.close();
+            continue;
+        }
+        if (nsent < nread) {
+            AP::FS().lseek(s.fd, nsent - nread, SEEK_CUR);
+        }
+    }
+    if (none_active) {
+        free(sendfile_buf);
+        sendfile_buf = nullptr;
+    }
+}
+
 AP_Networking *AP_Networking::singleton;
 
 namespace AP

libraries/AP_Networking/AP_Networking.h

@@ -188,6 +188,11 @@ public:
     static uint32_t convert_netmask_bitcount_to_ip(const uint32_t netmask_bitcount);
     static uint8_t convert_netmask_ip_to_bitcount(const uint32_t netmask_ip);
 
+    /*
+      send contents of a file to a socket then close both socket and file
+     */
+    bool sendfile(SocketAPM *sock, int fd);
+
     static const struct AP_Param::GroupInfo var_info[];
 
 private:
@@ -311,6 +316,16 @@ private:
     // ports for registration with serial manager
     Port ports[AP_NETWORKING_NUM_PORTS];
 
+    // support for sendfile()
+    struct SendFile {
+        SocketAPM *sock;
+        int fd;
+        void close(void);
+    } sendfiles[AP_NETWORKING_NUM_SENDFILES];
+
+    uint8_t *sendfile_buf;
+    void sendfile_check(void);
+
     void ports_init(void);
 };
 

libraries/AP_Networking/AP_Networking_Config.h

@@ -89,3 +89,11 @@
 #ifndef AP_NETWORKING_NUM_PORTS
 #define AP_NETWORKING_NUM_PORTS 4
 #endif
+
+#ifndef AP_NETWORKING_NUM_SENDFILES
+#define AP_NETWORKING_NUM_SENDFILES 20
+#endif
+
+#ifndef AP_NETWORKING_SENDFILE_BUFSIZE
+#define AP_NETWORKING_SENDFILE_BUFSIZE 10000
+#endif