diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
new file mode 100644
index 0000000..cf9e3e5
--- /dev/null
+++ b/.github/workflows/ci.yaml
@@ -0,0 +1,67 @@
+name: CI
+on:
+    pull_request:
+    push:
+        branches:
+            - "master"
+    workflow_dispatch:
+jobs:
+    build:
+        runs-on: ubuntu-20.04
+        name: Build on ${{ matrix.arch }} using ${{ matrix.cc }}
+
+        strategy:
+            matrix:
+                cc:
+                    - "gcc"
+                    - "clang"
+                arch:
+                    - "amd64"
+                    - "aarch64"
+                    - "ppc64le"
+        steps:
+            -   uses: actions/checkout@v2
+            -   uses: uraimo/run-on-arch-action@v2.1.1
+                if: ${{ matrix.arch != 'amd64' }}
+                name: Build and test
+                with:
+                    arch: ${{ matrix.arch }}
+                    distro: ubuntu20.04
+
+                    githubToken: ${{ github.token }}
+
+                    env: |
+                        CC: ${{ matrix.cc }}
+
+                    install: |
+                        apt-get update -y -q
+                        apt-get install -q -y \
+                            build-essential \
+                            clang \
+                            debhelper \
+                            libtool \
+                            liblua5.1-dev
+
+                    run: |
+                        # Build the package.
+                        (cd pkg && make deb)
+                        # Compile and run the tests.
+                        (cd src && make clean && DEBUG=1 make tests)
+
+            -   name: Build and test
+                if: ${{ matrix.arch == 'amd64' }}
+                env:
+                    CC: ${{ matrix.cc }}
+
+                run: |
+                    sudo apt-get install -q -y \
+                        build-essential \
+                        clang \
+                        debhelper \
+                        libtool \
+                        liblua5.1-dev
+
+                    # Build the package.
+                    (cd pkg && make deb)
+                    # Compile and run the tests.
+                    (cd src && make clean && DEBUG=1 make tests)
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2f00dca
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+build
+pkg/BUILD
+pkg/BUILDROOT
+pkg/RPMS
+pkg/SOURCES
+pkg/SRPMS
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index bf038d5..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,36 +0,0 @@
-language: c
-
-compiler:
-  - gcc
-  - clang
-
-dist: bionic
-
-matrix:
-  include:
-    - os: linux
-      arch: amd64
-    - os: linux
-      arch: arm64
-    - os: linux
-      arch: ppc64le
-
-addons:
-  apt:
-    update: true
-    packages:
-    - build-essential
-    - fakeroot
-    - debhelper
-    - libtool
-    - libtool-bin
-    - liblua5.1-dev
-    - lua5.1
-
-script:
-  # Build the package.
-  - (cd pkg && make deb)
-  # Compile and run the tests.
-  - (cd src && make clean && DEBUG=1 make tests)
-  # Install the DEB packages and run the Lua tests.
-  #- (sudo dpkg -i *.deb && cd src/lua && lua ./t_lpm.lua)
diff --git a/pkg/SPECS/liblpm.spec b/pkg/SPECS/liblpm.spec
index fa81b46..b83dad0 100644
--- a/pkg/SPECS/liblpm.spec
+++ b/pkg/SPECS/liblpm.spec
@@ -4,7 +4,7 @@
 
 Name:		liblpm
 Version:	%{version}
-Release:	3%{?dist}
+Release:	4%{?dist}
 Summary:	Longest Prefix Match (LPM) library
 Group:		System Environment/Libraries
 License:	BSD
diff --git a/src/Makefile b/src/Makefile
index d140512..e502e5d 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -40,44 +40,49 @@ else
 CFLAGS+=	-DNDEBUG
 endif
 
+# Build outside src/ so artifacts never end up in the source tarball.
+OUTDIR?=	../build
+
 # C library
 INCS=		lpm.h
-OBJS=		lpm.o
+OBJS=		$(OUTDIR)/lpm.o
 LIB=		liblpm
 
-$(LIB).la:	LDFLAGS+=	-rpath $(LIBDIR) -version-info 1:0:0
+$(OUTDIR)/$(LIB).la:	LDFLAGS+=	-rpath $(LIBDIR) -version-info 1:0:0
 install/%.la:	ILIBDIR=	$(DESTDIR)/$(LIBDIR)
 install:	IINCDIR=	$(DESTDIR)/$(INCDIR)/
 #install:	IMANDIR=	$(DESTDIR)/$(MANDIR)/man3/
 
 obj: $(OBJS)
 
-lib: $(LIB).la
+lib: $(OUTDIR)/$(LIB).la
+
+$(OUTDIR):
+	mkdir -p $@
 
-%.o: %.c
-	$(CC) $(CFLAGS) -c $<
+$(OUTDIR)/%.o: %.c | $(OUTDIR)
+	$(CC) $(CFLAGS) -c $< -o $@
 
-%.lo: %.c
-	libtool --mode=compile --tag CC $(CC) $(CFLAGS) -fPIC -c $<
+$(OUTDIR)/%.lo: %.c | $(OUTDIR)
+	libtool --mode=compile --tag CC $(CC) $(CFLAGS) -fPIC -c $< -o $@
 
-$(LIB).la: $(shell echo $(OBJS) | sed 's/\.o/\.lo/g')
-	libtool --mode=link --tag CC $(CC) $(LDFLAGS) -o $@ $(notdir $^)
+$(OUTDIR)/$(LIB).la: $(OUTDIR)/lpm.lo
+	libtool --mode=link --tag CC $(CC) $(LDFLAGS) -o $@ $^
 
-install/%.la: %.la
+install/%.la: $(OUTDIR)/%.la
 	mkdir -p $(ILIBDIR)
-	libtool --mode=install install -c $(notdir $@) $(ILIBDIR)/$(notdir $@)
+	libtool --mode=install install -c $< $(ILIBDIR)/$(notdir $@)
 
 install: $(addprefix install/,$(LIB).la)
 	libtool --mode=finish $(LIBDIR)
 	mkdir -p $(IINCDIR) && install -c $(INCS) $(IINCDIR)
 	#mkdir -p $(IMANDIR) && install -c $(MANS) $(IMANDIR)
 
-tests: $(OBJS) t_$(PROJ).o
-	$(CC) $(CFLAGS) $^ -o t_$(PROJ)
-	MALLOC_CHECK_=3 ./t_$(PROJ)
+tests: $(OBJS) $(OUTDIR)/t_$(PROJ).o
+	$(CC) $(CFLAGS) $^ -o $(OUTDIR)/t_$(PROJ)
+	MALLOC_CHECK_=3 $(OUTDIR)/t_$(PROJ)
 
 clean:
-	libtool --mode=clean rm
-	rm -rf .libs *.so *.o *.lo *.la t_$(PROJ)
+	rm -rf $(OUTDIR) .libs *.so *.o *.lo *.la t_$(PROJ)
 
 .PHONY: all obj lib install tests clean
diff --git a/src/jni/Makefile b/src/jni/Makefile
index d60fee1..9bd46a8 100644
--- a/src/jni/Makefile
+++ b/src/jni/Makefile
@@ -22,7 +22,7 @@ JAVA_HOME?=	/usr/lib/jvm/java/
 
 CFLAGS+=	-I.. -I$(JAVA_HOME)/include
 # Sadly, jni_md.h location is OS dependent
-CFLAGS+=	-I$(shell dirname $(shell find -L $(JAVA_HOME) -name jni_md.h))
+CFLAGS+=	-I$(shell dirname $(shell find -L $(JAVA_HOME) -name jni_md.h | head -1))
 
 OBJS=		org_netbsd_liblpm_LPM.o ../lpm.o
 LIB=		org_netbsd_liblpm_LPM
diff --git a/src/jni/org/netbsd/liblpm/LPM.java b/src/jni/org/netbsd/liblpm/LPM.java
index a898a30..61e5f80 100644
--- a/src/jni/org/netbsd/liblpm/LPM.java
+++ b/src/jni/org/netbsd/liblpm/LPM.java
@@ -45,6 +45,8 @@ public class LPM<T> {
 	private native int insert(long lpm, byte[] address, int prefixLength, T value);
 	private native T lookup(long lpm, String addr);
 	private native T lookup(long lpm, byte[] address);
+	private native T lookupPrefix(long lpm, String cidr);
+	private native T lookupPrefix(long lpm, byte[] address, int prefixLength);
 	private native int remove(long lpm, String cidr);
 	private native int remove(long lpm, byte[] address, int prefixLength);
 	private native void clear(long lpm);
@@ -106,6 +108,24 @@ public T lookup(byte[] address) {
 		return lookup(lpm, address);
 	}
 
+	public T lookupPrefix(String cidr) {
+		if (cidr == null) {
+			throw new IllegalArgumentException(
+				"cidr must not be null");
+		}
+
+		return lookupPrefix(lpm, cidr);
+	}
+
+	public T lookupPrefix(InetAddress inet, int prefixLength) {
+		return lookupPrefix(inet.getAddress(), prefixLength);
+	}
+
+	public T lookupPrefix(byte[] address, int prefixLength) {
+		validateCIDR(address, prefixLength);
+		return lookupPrefix(lpm, address, prefixLength);
+	}
+
 	public boolean remove(String cidr) {
 		if (cidr == null) {
 			throw new IllegalArgumentException(
diff --git a/src/jni/org/netbsd/liblpm/LPMTest.java b/src/jni/org/netbsd/liblpm/LPMTest.java
index ceefa7e..7939e54 100644
--- a/src/jni/org/netbsd/liblpm/LPMTest.java
+++ b/src/jni/org/netbsd/liblpm/LPMTest.java
@@ -45,6 +45,24 @@ private static void basicTest() throws Exception {
 		} catch(IllegalArgumentException e) {
 		}
 
+		assertEqual(lpm.lookupPrefix("10.0.0.0/9"), null);
+		assertEqual(lpm.lookupPrefix(InetAddress.getByName("10.0.0.0"), 9), null);
+		assertEqual(lpm.lookupPrefix(new byte[]{10, 0, 0, 0}, 9), null);
+		assertEqual(lpm.lookupPrefix("2001:db8::1/65"), null);
+		assertEqual(lpm.lookupPrefix(InetAddress.getByName("2001:db8::1"), 65), null);
+		assertEqual(lpm.lookupPrefix(new byte[]{
+			127, 0, 0, 0, 0, 0, 0, 0, 127, 0, 0, 0, 0, 0, 0, 0
+		}, 67), null);
+
+		assertEqual(lpm.lookupPrefix("10.0.0.0/8"), "foo");
+		assertEqual(lpm.lookupPrefix(InetAddress.getByName("10.0.0.0"), 8), "foo");
+		assertEqual(lpm.lookupPrefix(new byte[]{10, 0, 0, 0}, 8), "foo");
+		assertEqual(lpm.lookupPrefix("2001:db8::1/64"), "baz");
+		assertEqual(lpm.lookupPrefix(InetAddress.getByName("2001:db8::1"), 64), "baz");
+		assertEqual(lpm.lookupPrefix(new byte[]{
+			127, 0, 0, 0, 0, 0, 0, 0, 127, 0, 0, 0, 0, 0, 0, 0
+		}, 66), "raw6");
+
 		assertEqual(lpm.lookup("10.0.1.2"), "foo");
 		assertEqual(lpm.lookup("10.10.3.4"), "bar");
 		assertEqual(lpm.lookup("11.10.3.4"), null);
diff --git a/src/jni/org_netbsd_liblpm_LPM.c b/src/jni/org_netbsd_liblpm_LPM.c
index 8bb51d3..069549f 100644
--- a/src/jni/org_netbsd_liblpm_LPM.c
+++ b/src/jni/org_netbsd_liblpm_LPM.c
@@ -158,6 +158,54 @@ Java_org_netbsd_liblpm_LPM_lookup__J_3B(JNIEnv *env, jobject obj,
 	return ret;
 }
 
+JNIEXPORT jobject JNICALL
+Java_org_netbsd_liblpm_LPM_lookupPrefix__JLjava_lang_String_2
+    (JNIEnv *env, jobject obj, jlong lpm_ref, jstring cidr)
+{
+	lpm_t *lpm = (lpm_t *)lpm_ref;
+	const char *cidr_s;
+	uint32_t addr[4];
+	size_t len;
+	unsigned pref;
+	int ret;
+
+	cidr_s = (*env)->GetStringUTFChars(env, cidr, NULL);
+	if (cidr_s == NULL) {
+		return NULL;
+	}
+	ret = lpm_strtobin(cidr_s, addr, &len, &pref);
+	(*env)->ReleaseStringUTFChars(env, cidr, cidr_s);
+	if (ret != 0) {
+		return NULL;
+	}
+
+	return lpm_lookup_prefix(lpm, addr, len, pref);
+}
+
+JNIEXPORT jobject JNICALL
+Java_org_netbsd_liblpm_LPM_lookupPrefix__J_3BI
+    (JNIEnv *env, jobject obj, jlong lpm_ref, jbyteArray addr_ref, jint pref)
+{
+	lpm_t *lpm = (lpm_t *)lpm_ref;
+	jbyte *addr;
+	size_t len;
+	void *ret;
+
+	len = (*env)->GetArrayLength(env, addr_ref);
+	assert(len == 16 || len == 4);
+
+	addr = (*env)->GetByteArrayElements(env, addr_ref, NULL);
+	if (addr == NULL) {
+		return NULL;
+	}
+
+	ret = lpm_lookup_prefix(lpm, addr, len, pref);
+
+	(*env)->ReleaseByteArrayElements(env, addr_ref, addr, JNI_ABORT);
+
+	return ret;
+}
+
 JNIEXPORT jint JNICALL
 Java_org_netbsd_liblpm_LPM_remove__JLjava_lang_String_2(JNIEnv *env,
     jobject obj, jlong lpm_ref, jstring addr)
diff --git a/src/lua/Makefile b/src/lua/Makefile
index d9fa8f8..8239b66 100644
--- a/src/lua/Makefile
+++ b/src/lua/Makefile
@@ -36,27 +36,33 @@ LUA_CFLAGS?=	$(shell pkg-config --cflags lua)
 LUA_LDFLAGS?=	$(shell pkg-config --cflags --libs lua)
 CFLAGS+=	$(LUA_CFLAGS) -I.. -fPIC
 LDFLAGS+=	$(LUA_LDFLAGS)
-LDFLAGS+=	-L../.libs -llpm
+# Build outside src/ so artifacts never end up in the source tarball.
+OUTDIR?=	../../build/lua
+LIBLPM_OUTDIR?=	../../build
+LDFLAGS+=	-L$(LIBLPM_OUTDIR)/.libs -llpm
 
-OBJS=		lpm_lua.o
+OBJS=		$(OUTDIR)/lpm_lua.o
 LIB=		lpm
 
 install:	LUA_ILIBDIR=	$(DESTDIR)/$(LUA_LIBDIR)/
 
 obj: $(OBJS)
 
-lib: $(LIB).so
+lib: $(OUTDIR)/$(LIB).so
 
-%.o: %.c
-	$(CC) $(CFLAGS) -c $<
+$(OUTDIR):
+	mkdir -p $@
 
-$(LIB).so: $(OBJS)
-	$(CC) $(LDFLAGS) -fPIC -shared -o $@ $(notdir $^)
+$(OUTDIR)/%.o: %.c | $(OUTDIR)
+	$(CC) $(CFLAGS) -c $< -o $@
+
+$(OUTDIR)/$(LIB).so: $(OBJS)
+	$(CC) $(LDFLAGS) -fPIC -shared -o $@ $^
 
 install:
-	mkdir -p $(LUA_ILIBDIR) && install -c lpm.so $(LUA_ILIBDIR)
+	mkdir -p $(LUA_ILIBDIR) && install -c $(OUTDIR)/lpm.so $(LUA_ILIBDIR)
 
 clean:
-	rm -rf .libs *.so *.o *.lo *.la t_$(PROJ)
+	rm -rf $(OUTDIR) .libs *.so *.o *.lo *.la t_$(PROJ)
 
 .PHONY: all obj lib install clean