UTC:2025-11-25 8:46:57 :

source/main.cpp

@@ -343,19 +343,19 @@ int main(int argc, char *argv[])
     ::std::uint16_t listenPort
         = static_cast<::std::uint16_t>(::std::strtoul(argv[4], nullptr, 10));
 
-    // Create socket.
-    int fd = ::socket(AF_INET, SOCK_DGRAM, 0);
-    if (fd < 0) {
+    // Create receive socket.
+    int recvFd = ::socket(AF_INET, SOCK_DGRAM, 0);
+    if (recvFd < 0) {
         int err = errno;
         ::std::cerr << "Failed to create socket: " << ::strerror(err)
                     << ::std::endl;
         return -1;
     }
-    ::std::unique_ptr<int, void (*)(int *)> autoCloseFd(&fd,
-                                                        [](int *fd) -> void {
-                                                            ::close(*fd);
-                                                            *fd = -1;
-                                                        });
+    ::std::unique_ptr<int, void (*)(int *)> autoCloseRecvFd(
+        &recvFd, [](int *fd) -> void {
+            ::close(*fd);
+            *fd = -1;
+        });
 
     // Bind.
     ::sockaddr_in bindAddress;
@@ -366,8 +366,9 @@ int main(int argc, char *argv[])
         return -1;
     }
     bindAddress.sin_port = htons(listenPort);
-    auto bindResult = ::bind(fd, reinterpret_cast<::sockaddr *>(&bindAddress),
-                             sizeof(bindAddress));
+    auto bindResult
+        = ::bind(recvFd, reinterpret_cast<::sockaddr *>(&bindAddress),
+                 sizeof(bindAddress));
     if (bindResult < 0) {
         int err = errno;
         ::std::cerr << "Failed to bind listen port: " << ::strerror(err)
@@ -375,6 +376,26 @@ int main(int argc, char *argv[])
         return -1;
     }
 
+    // Reuse.
+    int opt = 1;
+    ::setsockopt(recvFd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    opt = 1;
+    ::setsockopt(recvFd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
+
+    // Create send socket.
+    int sendFd = ::socket(AF_INET, SOCK_DGRAM, 0);
+    if (sendFd < 0) {
+        int err = errno;
+        ::std::cerr << "Failed to create socket: " << ::strerror(err)
+                    << ::std::endl;
+        return -1;
+    }
+    ::std::unique_ptr<int, void (*)(int *)> autoCloseSendFd(
+        &sendFd, [](int *fd) -> void {
+            ::close(*fd);
+            *fd = -1;
+        });
+
     // Make send address.
     ::sockaddr_in targetAddress;
     ::memset(&targetAddress, 0, sizeof(targetAddress));
@@ -385,7 +406,7 @@ int main(int argc, char *argv[])
     }
     targetAddress.sin_port = htons(targetPort);
     auto connectResult
-        = ::connect(fd, reinterpret_cast<::sockaddr *>(&targetAddress),
+        = ::connect(sendFd, reinterpret_cast<::sockaddr *>(&targetAddress),
                     sizeof(targetAddress));
     if (connectResult < 0) {
         int err = errno;
@@ -395,10 +416,10 @@ int main(int argc, char *argv[])
     }
 
     // Reuse.
-    int opt = 1;
-    ::setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
     opt = 1;
-    ::setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
+    ::setsockopt(sendFd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    opt = 1;
+    ::setsockopt(sendFd, SOL_SOCKET, SO_REUSEPORT, &opt, sizeof(opt));
 
     // Create quit event.
     static int quitEvent = -1;
@@ -430,7 +451,7 @@ int main(int argc, char *argv[])
         auto now = ::std::chrono::steady_clock::now();
         if (now - nextTimestamp > ::std::chrono::seconds(1)) {
             // Send.
-            writeData(fd);
+            writeData(sendFd);
             nextTimestamp += ::std::chrono::seconds(1);
             if (now > nextTimestamp) {
                 nextTimestamp = now + ::std::chrono::seconds(1);
@@ -439,7 +460,7 @@ int main(int argc, char *argv[])
 
         // Wait for data.
         ::std::array<::pollfd, 2> fds {
-            ::pollfd {.fd = fd, .events = POLLIN, .revents = 0},
+            ::pollfd {.fd = recvFd, .events = POLLIN, .revents = 0},
             ::pollfd {.fd = quitEvent, .events = POLLIN, .revents = 0}};
         now             = ::std::chrono::steady_clock::now();
         auto pollResult = ::poll(
@@ -452,8 +473,8 @@ int main(int argc, char *argv[])
         if (pollResult > 0) {
             for (auto &status : fds) {
                 if (status.revents & POLLIN) {
-                    if (status.fd == fd) {
-                        ::readData(fd);
+                    if (status.fd == recvFd) {
+                        ::readData(recvFd);
                     } else if (status.fd == quitEvent) {
                         ::std::cout << "Quit event received." << ::std::endl;
                         return 0;