Supporting bpf on packets

.gitignore

@@ -11,6 +11,7 @@ pcap4j-test-coverage/src/
 # Gradle
 build/
 .gradle/
+.idea
 gradle-app.setting
 .gradletasknamecache
 

pcap4j-core/src/main/java/org/pcap4j/core/BpfProgram.java

@@ -37,6 +37,33 @@ public String getExpression() {
     return expression;
   }
 
+  /**
+   * Apply the filter on a given packet.
+   * Return true if the packet given passes the filter that is built from this program.
+   *
+   * @param packet the packet to apply the filter on
+   * @return true if the packet passes the filter
+   */
+  public boolean applyFilter(byte[] packet) {
+    return applyFilter(packet, packet.length, packet.length);
+  }
+
+  /**
+   * Apply the filter on a given packet.
+   * Return true if the packet given passes the filter that is built from this program.
+   *
+   * @param packet the packet to apply the filter on
+   * @param buflen the buffer len to use
+   * @return true if the packet passes the filter
+   */
+  public boolean applyFilter(byte[] packet, int wirelen, int buflen) {
+    if (program.bf_insns == null) {
+      program.read();
+    }
+
+    return NativeMappings.bpf_filter(program.bf_insns, packet, wirelen, buflen) != 0;
+  }
+
   /**
    *
    * @return true if the bpf_program represented by this object is freed;

pcap4j-core/src/main/java/org/pcap4j/core/NativeMappings.java

@@ -187,6 +187,10 @@ static native int pcap_compile_nopcap(
     int optimize, int mask
   );
 
+
+  // u_int	bpf_filter(const struct bpf_insn *, const u_char *, u_int, u_int)
+  static native int bpf_filter(bpf_insn.ByReference bpf_insn, byte[] packet, int wirelen, int buflen);
+
   // int pcap_setfilter(pcap_t *p, struct bpf_program *fp)
   static native int pcap_setfilter(Pointer p, bpf_program fp);