beautify

.dockerignore

+# Project exclude paths
+cmake-build-debug
+.idea
+Dockerfile
\ No newline at end of file

.gitignore

 # Project exclude paths
-/cmake-build-debug/
-/.idea/
+cmake-build-debug
+.idea
\ No newline at end of file

CMakeLists.txt

@@ -8,5 +8,5 @@ add_executable(tun main.cpp)
 find_package(Threads REQUIRED)
 target_link_libraries(tun Threads::Threads)
 
-#target_link_libraries(tun fmt)
+target_link_libraries(tun -static-libgcc -static-libstdc++)
 

Dockerfile

+FROM alpine AS builder
+RUN apk --no-cache add build-base cmake linux-headers
+
+WORKDIR /usr/src/app
+COPY . .
+RUN cmake -DCMAKE_BUILD_TYPE=Release .
+RUN make
+
+FROM alpine
+COPY --from=builder /usr/src/app/tun .
+
+RUN ["./tun"]
\ No newline at end of file

entrypoint.sh

+
+./tun $1
\ No newline at end of file

main.cpp

@@ -16,14 +16,14 @@ in_addr_t remote;
 // internet -> tun
 void inbound(int raw, int tun) {
     char buf[ETH_DATA_LEN];
-    sockaddr_in addr{AF_INET};
-    socklen_t addrlen;
-    size_t nread;
-    while ((nread = recvfrom(raw, buf, sizeof(buf), 0, (sockaddr *) &addr, &addrlen)) >= 0) {
-        std::cout << "recv " << nread << " bytes from" << inet_ntoa(addr.sin_addr) << std::endl;
+    sockaddr_in address{.sin_family = AF_INET};
+    socklen_t address_length;
+    size_t packet_length;
+    while ((packet_length = recvfrom(raw, buf, sizeof(buf), 0, (sockaddr *) &address, &address_length)) >= 0) {
+//        std::cout << "received " << packet_length << " bytes from " << inet_ntoa(address.sin_addr) << std::endl;
         auto *packet = (iphdr *) buf;
         auto overhead = packet->ihl * 4;
-        if (write(tun, buf + overhead, nread - overhead) < 0) {
+        if (write(tun, buf + overhead, packet_length - overhead) < 0) {
             perror("inbound write");
         }
     }
@@ -33,11 +33,11 @@ void inbound(int raw, int tun) {
 // tun -> internet
 void outbound(int raw, int tun) {
     char buf[ETH_DATA_LEN];
-    sockaddr_in addr{AF_INET};
-    addr.sin_addr.s_addr = remote;
-    size_t nread;
-    while ((nread = read(tun, buf, sizeof(buf))) >= 0) {
-        if (sendto(raw, buf, nread, 0, (sockaddr *) &addr, sizeof(addr)) < 0) {
+    sockaddr_in address{.sin_family = AF_INET};
+    address.sin_addr.s_addr = remote;
+    size_t packet_length;
+    while ((packet_length = read(tun, buf, sizeof(buf))) >= 0) {
+        if (sendto(raw, buf, packet_length, 0, (sockaddr *) &address, sizeof(address)) < 0) {
             perror("outbound write");
         }
     }