you can download it from the github: ssh:git clone git@github.com:openwrt/openwrt.git http:git clone https://github.com/openwrt/openwrt.git
or you can use the mirror source: git clone https://github.com/openwrt-mirror/openwrt.git
after unziping the package, enter the root path, update the code:
./scripts/feeds update -a ./sscripts/feeds install -athen choose the dut version which you need, then:
make V=s -jhttps://www.cnblogs.com/yaozuopan/p/12840424.html