Replace gen_ppi_dlt_check() with gen_cmp().

Use simpler C code to generate exactly the same filter program.

diff --git a/gencode.c b/gencode.c
index 6aeb0af33cb72e44845b09b588685e63910b4998..a9fe859b52d1d79f0fdffa3540ac03a10344c131 100644 (file)
--- a/gencode.c
+++ b/gencode.c
@@ -710,7 +710,6 @@ static struct block *gen_mac_multicast(compiler_state_t *, int);
 static struct block *gen_len(compiler_state_t *, int, int);
 static struct block *gen_encap_ll_check(compiler_state_t *cstate);
 
-static struct block *gen_ppi_dlt_check(compiler_state_t *);
 static struct block *gen_atmfield_code_internal(compiler_state_t *, int,
     bpf_u_int32, int, int);
 static struct block *gen_atmtype_llc(compiler_state_t *);
@@ -1103,8 +1102,6 @@ merge(struct block *b0, struct block *b1)
 int
 finish_parse(compiler_state_t *cstate, struct block *p)
 {
-       struct block *ppi_dlt_check;
-
        /*
         * Catch errors reported by us and routines below us, and return -1
         * on an error.
@@ -1146,9 +1143,11 @@ finish_parse(compiler_state_t *cstate, struct block *p)
         * 802.11 code (*and* anything else for which PPI is used)
         * and choose between them early in the BPF program?
         */
-       ppi_dlt_check = gen_ppi_dlt_check(cstate);
-       if (ppi_dlt_check != NULL)
+       if (cstate->linktype == DLT_PPI) {
+               struct block *ppi_dlt_check = gen_cmp(cstate, OR_PACKET,
+                       4, BPF_W, SWAPLONG(DLT_IEEE802_11));
                gen_and(ppi_dlt_check, p);
+       }
 
        backpatch(p, gen_retblk_internal(cstate, cstate->snaplen));
        p->sense = !p->sense;
@@ -3167,32 +3166,6 @@ insert_compute_vloffsets(compiler_state_t *cstate, struct block *b)
        }
 }
 
-static struct block *
-gen_ppi_dlt_check(compiler_state_t *cstate)
-{
-       struct slist *s_load_dlt;
-       struct block *b;
-
-       if (cstate->linktype == DLT_PPI)
-       {
-               /* Create the statements that check for the DLT
-                */
-               s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
-               s_load_dlt->s.k = 4;
-
-               b = new_block(cstate, JMP(BPF_JEQ));
-
-               b->stmts = s_load_dlt;
-               b->s.k = SWAPLONG(DLT_IEEE802_11);
-       }
-       else
-       {
-               b = NULL;
-       }
-
-       return b;
-}
-
 /*
  * Take an absolute offset, and:
  *