From Florent Drouin: add support for filtering on MTP2 frame types.

[libpcap] / gencode.c

diff --git a/gencode.c b/gencode.c
index 324749293d7f46f4889d1d2fbea6d3552bdbd100..fcc9c1cc02a851da07a20961556f70a55491ab51 100644 (file)
--- a/gencode.c
+++ b/gencode.c
@@ -21,7 +21,7 @@
  */
 #ifndef lint
 static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.221.2.44 2006-10-13 08:56:07 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.221.2.45 2006-12-21 19:45:03 guy Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -724,6 +724,11 @@ static u_int off_vpi;
 static u_int off_vci;
 static u_int off_proto;
 
+/*
+ * These are offsets for the MTP2 fields.
+ */
+static u_int off_li;
+
 /*
  * These are offsets for the MTP3 fields.
  */
@@ -790,6 +795,7 @@ init_linktype(p)
        /*
         * And assume we're not doing SS7.
         */
+       off_li = -1;
        off_sio = -1;
        off_opc = -1;
        off_dpc = -1;
@@ -1217,6 +1223,7 @@ init_linktype(p)
                return;
 
        case DLT_MTP2:
+               off_li = 2;
                off_sio = 3;
                off_opc = 4;
                off_dpc = 4;
@@ -6748,6 +6755,47 @@ gen_atmtype_abbrev(type)
        return b1;
 }
 
+/* 
+ * Filtering for MTP2 messages based on li value
+ * FISU, length is null
+ * LSU, length is 1 or 2
+ * MSU, length is 3 or more
+ */
+struct block *
+gen_mtp2type_abbrev(type)
+       int type;
+{
+       struct block *b0, *b1;
+
+       switch (type) {
+
+       case M_FISU:
+               if (linktype != DLT_MTP2)
+                       bpf_error("'fisu' supported only on MTP2");
+               /* gen_ncmp(offrel, offset, size, mask, jtype, reverse, value) */
+               b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
+               break;
+
+       case M_LSU:
+               if (linktype != DLT_MTP2)
+                       bpf_error("'lsu' supported only on MTP2");
+               b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
+               b1 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
+               gen_and(b1, b0);
+               break;
+
+       case M_MSU:
+               if (linktype != DLT_MTP2)
+                       bpf_error("'msu' supported only on MTP2");
+               b0 = gen_ncmp(OR_PACKET, off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
+               break;
+
+       default:
+               abort();
+       }
+       return b0;
+}
+
 struct block *
 gen_mtp3field_code(mtp3field, jvalue, jtype, reverse)
        int mtp3field;