compiler: squelch a warning from MSVC.

Cast the sum of SKF_AD_OFF and a metadata field offset to bpf_u_int32
before making it the k field of an instruction.  SKF_AD_OFF is negative,
as is the sum in question, so you have to cast it.

Author: guyharris

gencode.c

@@ -9273,7 +9273,7 @@ gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid)
 	unsigned cnt;
 
 	s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
-	s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
+	s->s.k = (bpf_u_int32)(SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT);
 
 	/* true -> next instructions, false -> beginning of b_vid */
 	sjeq = new_stmt(cstate, JMP(BPF_JEQ));
@@ -9282,7 +9282,7 @@ gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid)
 	sappend(s, sjeq);
 
 	s2 = new_stmt(cstate, BPF_LD|BPF_H|BPF_ABS);
-	s2->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG;
+	s2->s.k = (bpf_u_int32)(SKF_AD_OFF + SKF_AD_VLAN_TAG);
 	sappend(s, s2);
 	sjeq->s.jt = s2;
 
@@ -9320,7 +9320,7 @@ gen_vlan_bpf_extensions(compiler_state_t *cstate, bpf_u_int32 vlan_num,
 	/* generate new filter code based on extracting packet
 	 * metadata */
 	s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
-	s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
+	s->s.k = (bpf_u_int32)(SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT);
 
 	b0 = new_block(cstate, JMP(BPF_JEQ));
 	b0->stmts = s;