Enabled IPV6_V6ONLY option for tcp IPv6 bind logic, net.ipv6.bindv6on…

.gitignore

@@ -1,3 +1,4 @@
+cmake-build
 *.o
 Makefile.depend
 udptunnel

CMakeLists.txt

@@ -0,0 +1,35 @@
+cmake_minimum_required (VERSION 3.10)
+project ("udptunnel" "C")
+
+if (PROJECT_SOURCE_DIR STREQUAL PROJECT_BINARY_DIR)
+  message (FATAL_ERROR "In-source builds are not allowed")
+endif ()
+
+set (CMAKE_PROJECT_DESCRIPTION "UDP tunnel over TCP")
+set (CMAKE_PROJECT_HOMEPAGE_URL "https://github.com/andrew-aladjev/udptunnel")
+set (PROJECT_VERSION "1.2.1")
+
+if (NOT DEFINED CMAKE_INSTALL_BINDIR)
+  set (CMAKE_INSTALL_BINDIR "sbin" CACHE PATH "output directory for binaries")
+endif ()
+
+set (CMAKE_C_FLAGS "-O2 -std=c11 -Wall")
+set (CMAKE_EXE_LINKER_FLAGS "-static")
+
+if (NOT DEFINED CMAKE_BUILD_TYPE OR CMAKE_BUILD_TYPE STREQUAL "")
+  set (CMAKE_BUILD_TYPE "Release")
+endif ()
+
+set (
+  SOURCES
+  "log.c"
+  "network.c"
+  "udptunnel.c"
+  "utils.c"
+)
+
+add_executable (${PROJECT_NAME} ${SOURCES})
+install (TARGETS ${PROJECT_NAME} RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
+include (CPackConfig.cmake)
+include (CPack)

CPackConfig.cmake

@@ -0,0 +1,29 @@
+set (CPACK_PACKAGE_NAME ${PROJECT_NAME})
+set (CPACK_PACKAGE_VERSION ${PROJECT_VERSION})
+set (CPACK_RESOURCE_FILE_README  "${PROJECT_SOURCE_DIR}/README.md")
+set (CPACK_RESOURCE_FILE_LICENSE "${PROJECT_SOURCE_DIR}/COPYING")
+
+set (CPACK_PACKAGE_LICENSE "LGPLv2")
+set (CPACK_RPM_PACKAGE_LICENSE ${CPACK_PACKAGE_LICENSE})
+set (CPACK_FREEBSD_PACKAGE_LICENSE ${CPACK_PACKAGE_LICENSE})
+
+set (CPACK_PACKAGE_MAINTAINER "Andrew Aladjev <andrew-aladjev@gmail.com>")
+set (CPACK_DEBIAN_PACKAGE_MAINTAINER ${CPACK_PACKAGE_MAINTAINER})
+set (CPACK_FREEBSD_PACKAGE_MAINTAINER ${CPACK_PACKAGE_MAINTAINER})
+
+set (CPACK_DEBIAN_PACKAGE_SECTION "net")
+set (CPACK_FREEBSD_PACKAGE_ORIGIN "net/${PROJECT_NAME}")
+
+set (CPACK_PACKAGE_ARCHITECTURE "amd64")
+set (CPACK_DEBIAN_PACKAGE_ARCHITECTURE ${CPACK_PACKAGE_ARCHITECTURE})
+set (CPACK_RPM_PACKAGE_ARCHITECTURE ${CPACK_PACKAGE_ARCHITECTURE})
+
+if (CMAKE_SYSTEM_NAME MATCHES "Linux")
+  set (CPACK_GENERATOR "DEB" "RPM")
+elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+  set (CPACK_GENERATOR "FREEBSD")
+endif ()
+
+set (PACKAGE_NAME "${CPACK_PACKAGE_NAME}")
+set (CPACK_PACKAGE_FILE_NAME "${PACKAGE_NAME}-${CPACK_PACKAGE_VERSION}.${CPACK_PACKAGE_ARCHITECTURE}")
+set (CPACK_STRIP_FILES true)

README.md

@@ -0,0 +1,17 @@
+UDP tunnel over TCP. License: LGPLv2.
+
+Please build it using the following commands:
+
+```bash
+rm -rf cmake-build
+cmake -S . -B cmake-build
+cmake --build cmake-build
+cmake --build cmake-build --target package
+```
+
+After that you will receive packages for DEB-based and RPM-based distros:
+
+```
+cmake-build/udptunnel-*.amd64.deb
+cmake-build/udptunnel-*.amd64.rpm
+```

network.c

@@ -198,6 +198,11 @@ int *tcp_listener(const char *s)
 	if ((fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol)) < 0)
 	    continue;		/* ignore */
 	opt = 1;
+	if (ai->ai_family == AF_INET6) {
+	    /* we are going to bind to IPv6 address only */
+	    if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &opt, sizeof(opt)) < 0)
+	        err_sys("setsockopt(IPPROTO_IPV6, IPV6_V6ONLY)");
+	}
 	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0)
 	    err_sys("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
 	if (bind(fd, (struct sockaddr *) ai->ai_addr, ai->ai_addrlen) < 0)

udptunnel.c

@@ -379,9 +379,7 @@ static void tcp_to_udp(struct relay *relay)
 
 static void send_handshake(struct relay *relay)
 {
-    if (sendto(relay->tcp_sock, relay->handshake, sizeof(relay->handshake), 0,
-	       (struct sockaddr *) &relay->remote_udpaddr,
-	       sizeof(relay->remote_udpaddr)) < 0)
+    if (send(relay->tcp_sock, relay->handshake, sizeof(relay->handshake), 0) < 0)
 	err_sys("sendto(tcp, handshake)");
 }