use socat

Dockerfile

-FROM debian:bullseye as base
-RUN apt update && \
-    apt -y install build-essential && \
-    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
-
-FROM base as builder
-
-WORKDIR /build
-COPY ./Makefile ./
-COPY ./proxy.c ./
-RUN make
-
-FROM base
+FROM debian:bullseye-slim
 
 RUN apt update && \
-    env DEBIAN_FRONTEND=noninteractive apt -y install curl gnupg2 libcap2-bin && \
+    env DEBIAN_FRONTEND=noninteractive apt -y install curl gnupg2 libcap2-bin socat && \
     curl https://pkg.cloudflareclient.com/pubkey.gpg | apt-key add - && \
     echo 'deb http://pkg.cloudflareclient.com/ bullseye main' | tee /etc/apt/sources.list.d/cloudflare-client.list && \
     apt update && \
@@ -25,7 +13,6 @@ RUN apt update && \
 
 WORKDIR /usr/src/app
 
-COPY --from=builder /build/proxy ./proxy
 COPY ./entrypoint.sh ./
 
 ENV LOCAL_PROXY_PORT 10080
@@ -33,4 +20,4 @@ ENV FORWARD_PROXY_PORT 8080
 EXPOSE $FORWARD_PROXY_PORT
 
 ENTRYPOINT [ "./entrypoint.sh" ]
-CMD ["bash", "-c", "./proxy -l $FORWARD_PROXY_PORT -h localhost -p $LOCAL_PROXY_PORT -f"]
+CMD ["bash", "-c", "socat tcp-listen:$FORWARD_PROXY_PORT,fork tcp:localhost:$LOCAL_PROXY_PORT"]

Makefile

-CFLAGS=-O2 -std=c99 -Wall
-OPTFLAGS=-s -DUSE_SPLICE
-LDFLAGS=
-
-all:
-	gcc $(CFLAGS) $(OPTFLAGS) -o proxy proxy.c $(LDFLAGS)
-tomato:
-	mipsel-uclibc-gcc $(CFLAGS) $(OPTFLAGS) -o proxy proxy.c $(LDFLAGS)
-openwrt:
-	mipsel-linux-uclibc-gcc $(CFLAGS) $(OPTFLAGS) -o proxy proxy.c $(LDFLAGS)
-backfire:
-	mipsel-openwrt-linux-uclibc-gcc $(CFLAGS) $(OPTFLAGS) -o proxy proxy.c $(LDFLAGS)
-darwin:
-	gcc $(CFLAGS) -o proxy proxy.c $(LDFLAGS)
-clean:
-	rm -f proxy proxy.exe