[Docker] masscan on alpine

masscan.Dockerfile

# Example: 
#  $ docker build -t masscan -f masscan.Dockerfile .
#  $ docker run --rm -it --net=host masscan -p0-65535 192.168.0.0/16 --rate 1000000
# --net=host is optional but I saw rate limit without it
# -v $(pwd):/opt if you want to feed result files back out
FROM alpine as builder
LABEL author "Peng Liu"
LABEL email "myme5261314@gmail.com"

ARG MASSCAN_GIT_URL=https://github.com/robertdavidgraham/masscan

RUN set -ex; \
    apk --update add --no-cache \
        ca-certificates \
        clang \
        clang-dev \
        gcc \
        git \
        libc-dev \
        linux-headers \
        make \
        libpcap-dev && \
    git clone "$MASSCAN_GIT_URL"; \
    cd masscan && \
        make -j4 && \
        cp bin/masscan /usr/local/bin/ && \
    cd .. && \
    rm -rf masscan

FROM alpine
LABEL author "Joe Eaves"
LABEL email "joe.eaves@shadowacre.ltd"

RUN apk --update add --no-cache libpcap-dev
COPY --from=builder /usr/local/bin/masscan /usr/local/bin/masscan

ENTRYPOINT ["/usr/local/bin/masscan"]
WORKDIR /opt