move OID decoding to wrapper function

to avoid conditions in the hot path

diff --git a/src/protocols/der/decode.c b/src/protocols/der/decode.c
index 60ca69dec1e913f466746484105351a0165b4871..1749c477d072d25abf6941d6166a8e18d5091728 100644 (file)
--- a/src/protocols/der/decode.c
+++ b/src/protocols/der/decode.c
@@ -1698,10 +1698,33 @@ static ssize_t fr_der_decode_combo_ip_addr(TALLOC_CTX *ctx, fr_pair_list_t *out,
        return fr_dbuff_set(in, &our_in);
 }
 
+static ssize_t fr_der_decode_oid_wrapper(TALLOC_CTX *ctx, fr_pair_list_t *out, fr_dict_attr_t const *parent,
+                                        fr_dbuff_t *in, UNUSED fr_der_decode_ctx_t *decode_ctx)
+{
+       ssize_t slen;
+       fr_der_decode_oid_to_str_ctx_t uctx = {
+               .ctx         = ctx,
+               .parent_da   = parent,
+               .parent_list = out,
+               .oid_buff = {},
+               .marker = {},
+       };
+
+       /*
+        *      We don't use an intermediate dbuff here.  We're not
+        *      doing anything with the dbuff, so an extra buffer
+        *      isn't necessary.
+        */
+       slen = fr_der_decode_oid(out, in, fr_der_decode_oid_to_str, &uctx);
+       if (unlikely(slen <= 0)) return -1; /* OIDs of zero length are invalid */
+
+       return slen;
+}
 
 static const fr_der_tag_decode_t tag_funcs[FR_DER_TAG_VALUE_MAX] = {
        [FR_DER_TAG_BOOLEAN]          = { .constructed = FR_DER_TAG_PRIMITIVE, .decode = fr_der_decode_boolean },
        [FR_DER_TAG_INTEGER]          = { .constructed = FR_DER_TAG_PRIMITIVE, .decode = fr_der_decode_integer },
+       [FR_DER_TAG_OID]              = { .constructed = FR_DER_TAG_PRIMITIVE, .decode = fr_der_decode_oid_wrapper },
        [FR_DER_TAG_BITSTRING]        = { .constructed = FR_DER_TAG_PRIMITIVE, .decode = fr_der_decode_bitstring },
        [FR_DER_TAG_OCTETSTRING]      = { .constructed = FR_DER_TAG_PRIMITIVE, .decode = fr_der_decode_octetstring },
        [FR_DER_TAG_NULL]             = { .constructed = FR_DER_TAG_PRIMITIVE, .decode = fr_der_decode_null },
@@ -1839,19 +1862,14 @@ static ssize_t fr_der_decode_hdr(fr_dict_attr_t const *parent, fr_dbuff_t *in, u
        func = &tag_funcs[*tag];
        fr_assert(func != NULL);
 
-       /*
-        *      Check if the tag is an OID. OID tags will be handled differently
-        */
-       if (*tag != FR_DER_TAG_OID) {
-               if (unlikely(func->decode == NULL)) {
-                       fr_strerror_printf("No decode function for tag %u", *tag);
-                       return -1;
-               }
+       if (unlikely(func->decode == NULL)) {
+               fr_strerror_printf("No decode function for tag %u", *tag);
+               return -1;
+       }
 
-               if (IS_DER_TAG_CONSTRUCTED(func->constructed) != constructed) {
-                       fr_strerror_printf("Constructed flag mismatch for tag %u", *tag);
-                       return -1;
-               }
+       if (IS_DER_TAG_CONSTRUCTED(func->constructed) != constructed) {
+               fr_strerror_printf("Constructed flag mismatch for tag %u", *tag);
+               return -1;
        }
 
        FR_DBUFF_OUT_RETURN(&len_byte, &our_in);
@@ -2618,33 +2636,19 @@ static ssize_t fr_der_decode_pair_dbuff(TALLOC_CTX *ctx, fr_pair_list_t *out, fr
                break;
        }
 
-       if (tag != FR_DER_TAG_OID) {
-               fr_assert(func->decode != NULL);
-
-               /*
-                *      The decode function can return 0 if len==0.  This is true for 'null' data types, and
-                *      for variable-sized types such as strings.
-                */
-               fr_dbuff_set_end(&our_in, fr_dbuff_current(&our_in) + len);
-               slen = func->decode(ctx, out, parent, &our_in, decode_ctx);
-               if (unlikely(slen < 0)) return slen;
-
-       } else {
-               fr_der_decode_oid_to_str_ctx_t uctx = {
-                       .ctx         = ctx,
-                       .parent_da   = parent,
-                       .parent_list = out,
-                       .oid_buff = {},
-                       .marker = {},
-               };
-
-               fr_assert(uctx.parent_da != NULL);
+       /*
+        *      Limit the length of the data to be decoded.
+        */
+       fr_dbuff_set_end(&our_in, fr_dbuff_current(&our_in) + len);
 
-               fr_dbuff_set_end(&our_in, fr_dbuff_current(&our_in) + len);
+       fr_assert(func->decode != NULL);
 
-               slen = fr_der_decode_oid(out, &our_in, fr_der_decode_oid_to_str, &uctx);
-               if (unlikely(slen <= 0)) return slen;
-       }
+       /*
+        *      The decode function can return 0 if len==0.  This is true for 'null' data types, and
+        *      for variable-sized types such as strings.
+        */
+       slen = func->decode(ctx, out, parent, &our_in, decode_ctx);
+       if (unlikely(slen < 0)) return slen;
 
        /*
         *      There may be extra data, in which case we ignore it.