+/*
+ * 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;
+}
+