diff --git a/docker-build.sh b/docker-build.sh
index 37a0740..65c0811 100755
--- a/docker-build.sh
+++ b/docker-build.sh
@@ -2,37 +2,37 @@
 
 set -ex
 
-DOCKERFILE="${DOCKERFILE:-Dockerfile}"
 # Copy Dockerfile inside build context to support older Docker versions
 # See https://github.com/docker/cli/pull/886
-cp "$DOCKERFILE" ./build/
-TMP_IMAGE_NAME=$(tr -dc '[:lower:]' < /dev/urandom | fold -w 32 | head -n 1)
-docker build -t "$TMP_IMAGE_NAME" -f "./build/$DOCKERFILE" ./build
+cp "$DOCKERFILE" ./build/Dockerfile
+TMP_IMAGE_NAME=$(tr -dc '[:lower:]' </dev/urandom | fold -w 32 | head -n 1)
+docker build -t "$TMP_IMAGE_NAME" -f "./build/Dockerfile" ./build
 
 for IMAGE in $DOCKER_IMAGE; do
 	docker tag "$TMP_IMAGE_NAME" "$IMAGE:$TARGET-$VERSION"
 
 	if [ -n "$ARCH" ]; then
-	    docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:$ARCH-$VERSION"
-	fi
+		docker tag "$TMP_IMAGE_NAME" "$IMAGE:$ARCH-$VERSION"
+		docker tag "$TMP_IMAGE_NAME" "$IMAGE:$ARCH-$BRANCH"
 
-	if [ "$VERSION" == "snapshot" ]; then
-	    docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:$TARGET-$BRANCH"
-
-	    if [ -n "$ARCH" ]; then
-		docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:$ARCH"
-	    fi
-	    docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:$TARGET"
-
-	    if [ "$TARGET" == "x86-64" ]; then
-		docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:$BRANCH"
-		docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:latest"
-	    fi
+		if [ "$VERSION" == "snapshot" ]; then
+			docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:$ARCH"
+		fi
 	fi
 
 	if [ "$TARGET" == "x86-64" ]; then
-	    docker tag "$IMAGE:$TARGET-$VERSION" "$IMAGE:$VERSION"
+		docker tag "$TMP_IMAGE_NAME" "$IMAGE:$VERSION"
+		docker tag "$TMP_IMAGE_NAME" "$IMAGE:$BRANCH"
+
+		if [ "$VERSION" == "snapshot" ]; then
+			docker tag "$TMP_IMAGE_NAME" "$IMAGE:latest"
+		fi
 	fi
+
+	for TARGET_TAG in $TARGETS; do
+		TARGET_TAG=$(echo "$TARGET_TAG" | tr '/' '-')
+		docker tag "$TMP_IMAGE_NAME" "$IMAGE:$TARGET_TAG-$VERSION"
+	done
 done
 
 docker rmi "$TMP_IMAGE_NAME"
diff --git a/docker-imagebuilder.sh b/docker-imagebuilder.sh
index a13f169..5f2f72b 100755
--- a/docker-imagebuilder.sh
+++ b/docker-imagebuilder.sh
@@ -2,24 +2,12 @@
 
 set -ex
 
-TARGET=$(echo "$CI_JOB_NAME" | cut -d _ -f 2-)
-export TARGET="${TARGET:-x86-64}"
-export VERSION="${VERSION:-snapshot}"
+. ./functions.sh
+
 export DOCKER_IMAGE="${DOCKER_IMAGE:-openwrt-imagebuilder}"
 export DOWNLOAD_FILE="openwrt-imagebuilder.*x86_64.tar.xz"
 
-if [ "$VERSION" = "snapshot" ]; then
-	export BRANCH="master"
-else
-	export BRANCH="openwrt-${VERSION%.*}"
-fi
-
-if [ "$VERSION" == "snapshot" ]; then
-	DOWNLOAD_PATH="snapshots/targets/$(echo "$TARGET" | tr '-' '/')"
-else
-	DOWNLOAD_PATH="releases/$VERSION/targets/$(echo "$TARGET" | tr '-' '/')"
-fi
-export DOWNLOAD_PATH
+export_variables
 
 ./docker-download.sh || exit 1
 ./docker-build.sh || exit 1
diff --git a/docker-rootfs.sh b/docker-rootfs.sh
index a676df8..e7b1cb6 100755
--- a/docker-rootfs.sh
+++ b/docker-rootfs.sh
@@ -2,25 +2,13 @@
 
 set -ex
 
-TARGET=$(echo "$CI_JOB_NAME" | cut -d _ -f 2-)
-export TARGET="${TARGET:-x86-64}"
-export VERSION="${VERSION:-snapshot}"
+. ./functions.sh
+
 export DOCKER_IMAGE="${DOCKER_IMAGE:-openwrt-rootfs}"
 export DOWNLOAD_FILE="openwrt-.*-rootfs.tar.gz"
 export DOCKERFILE="Dockerfile.rootfs"
 
-if [ "$VERSION" = "snapshot" ]; then
-	export BRANCH="master"
-else
-	export BRANCH="openwrt-${VERSION%.*}"
-fi
-
-if [ "$VERSION" = "snapshot" ]; then
-	DOWNLOAD_PATH="snapshots/targets/$(echo "$TARGET" | tr '-' '/')"
-else
-	DOWNLOAD_PATH="releases/$VERSION/targets/$(echo "$TARGET" | tr '-' '/')"
-fi
-export DOWNLOAD_PATH
+export_variables
 
 ./docker-download.sh || exit 1
 
diff --git a/docker-sdk.sh b/docker-sdk.sh
index 366cd07..703878b 100755
--- a/docker-sdk.sh
+++ b/docker-sdk.sh
@@ -2,64 +2,18 @@
 
 set -ex
 
-ARCH=$(echo "$CI_JOB_NAME" | cut -d _ -f 2-)
-# take the first supported target from TARGETS list
-# shellcheck disable=SC2153
-TARGET=$(echo "$TARGETS" | cut -d ' ' -f 1)
-export TARGET="${TARGET:-x86-64}"
-export ARCH="${ARCH:-x86_64}"
-export VERSION="${VERSION:-snapshot}"
+. ./functions.sh
+
 export DOCKER_IMAGE="${DOCKER_IMAGE:-openwrt-sdk}"
 export DOWNLOAD_FILE="openwrt-sdk-.*.Linux-x86_64.tar.xz"
+# take the first supported target from TARGETS list
+# shellcheck disable=SC2153,SC2034
+TARGET=$(echo "$TARGETS" | cut -d ' ' -f 1)
 
-if [ "$VERSION" = "snapshot" ]; then
-	export BRANCH="master"
-else
-	export BRANCH="openwrt-${VERSION%.*}"
-fi
-
-if [ "$VERSION" == "snapshot" ]; then
-	DOWNLOAD_PATH="snapshots/targets/$(echo "$TARGET" | tr '-' '/')"
-else
-	DOWNLOAD_PATH="releases/$VERSION/targets/$(echo "$TARGET" | tr '-' '/')"
-fi
-export DOWNLOAD_PATH
+export_variables
 
 ./docker-download.sh || exit 1
 
 echo "Using SDK from revision $(sed -ne 's/REVISION:=//p' ./build/include/version.mk)"
 
-DOCKERFILE="${DOCKERFILE:-Dockerfile}"
-# Copy Dockerfile inside build context to support older Docker versions
-# See https://github.com/docker/cli/pull/886
-cp "$DOCKERFILE" ./build/
-
-TMP_IMAGE_NAME=$(tr -dc '[:lower:]' < /dev/urandom | fold -w 32 | head -n 1)
-docker build -t "$TMP_IMAGE_NAME" -f "./build/$DOCKERFILE" ./build
-
-for IMAGE in $DOCKER_IMAGE; do
-	docker tag "$TMP_IMAGE_NAME" "$IMAGE:$ARCH-$VERSION"
-
-	if [ "$VERSION" == "snapshot" ]; then
-	    docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:$ARCH-$BRANCH"
-
-	    docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:$ARCH"
-	    if [ "$ARCH" == "x86_64" ]; then
-		docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:$BRANCH"
-		docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:latest"
-	    fi
-	fi
-
-	if [ "$ARCH" == "x86_64" ]; then
-	    docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:$VERSION"
-	fi
-
-	for TARGET_TAG in $TARGETS; do
-	    TARGET_TAG=$(echo "$TARGET_TAG" | tr '/' '-')
-	    docker tag "$IMAGE:$ARCH-$VERSION" "$IMAGE:$TARGET_TAG-$VERSION"
-	done
-done
-
-docker rmi "$TMP_IMAGE_NAME"
-
-rm -rf ./build
+./docker-build.sh || exit 1
diff --git a/functions.sh b/functions.sh
new file mode 100644
index 0000000..c80faf4
--- /dev/null
+++ b/functions.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+set -ex
+
+export_variables() {
+	ARCH=$(echo "$CI_JOB_NAME" | cut -d _ -f 2-)
+	export TARGET="${TARGET:-x86-64}"
+	export ARCH="${ARCH:-x86_64}"
+	export VERSION="${VERSION:-snapshot}"
+	export DOCKERFILE="${DOCKERFILE:-Dockerfile}"
+
+	case "$VERSION" in
+	snapshot)
+		export BRANCH="master"
+		;;
+	*-SNAPSHOT)
+		export BRANCH="openwrt-${VERSION%-*}"
+		;;
+	*)
+		export BRANCH="openwrt-${VERSION%.*}"
+		;;
+	esac
+
+	if [ "$VERSION" = "snapshot" ]; then
+		DOWNLOAD_PATH="snapshots/targets/$(echo "$TARGET" | tr '-' '/')"
+	else
+		DOWNLOAD_PATH="releases/$VERSION/targets/$(echo "$TARGET" | tr '-' '/')"
+	fi
+	export DOWNLOAD_PATH
+}