Use dbuff primitives to read/write from dbuffs. (#3912)

diff --git a/src/protocols/tacacs/encode.c b/src/protocols/tacacs/encode.c
index 07c60db757a54575aac4c2495e3290091ea69d53..155260a5448e26028c822ddabec46afb3cd40360 100644 (file)
--- a/src/protocols/tacacs/encode.c
+++ b/src/protocols/tacacs/encode.c
@@ -130,7 +130,8 @@ ssize_t fr_tacacs_encode(fr_dbuff_t *dbuff, uint8_t const *original_packet, char
        ssize_t                 len = 0;
        size_t                  body_len, packet_len;
        fr_dbuff_t              work_dbuff = FR_DBUFF_NO_ADVANCE(dbuff);
-       fr_dbuff_marker_t       hdr, body;
+       fr_dbuff_marker_t       hdr, body, hdr_io;
+       uint8_t                 version_byte;
 
        fr_tacacs_packet_hdr_t const *original = (fr_tacacs_packet_hdr_t const *) original_packet;
 
@@ -165,6 +166,10 @@ ssize_t fr_tacacs_encode(fr_dbuff_t *dbuff, uint8_t const *original_packet, char
         *      Let's keep reference for packet header.
         */
        fr_dbuff_marker(&hdr, &work_dbuff);
+       /*
+        *      Add marker letting us read/write header bytes without moving hdr.
+        */
+       fr_dbuff_marker(&hdr_io, &work_dbuff);
 
        /*
         *      Handle the fields in-place.
@@ -556,8 +561,13 @@ ssize_t fr_tacacs_encode(fr_dbuff_t *dbuff, uint8_t const *original_packet, char
                        /*
                         *      Just to avoid malformed packet.
                         */
-                       if (!fr_dbuff_current(&hdr)[0]) fr_dbuff_current(&hdr)[0] = 0xc1; /* version 12.1 */
-
+                       fr_dbuff_set(&hdr_io, &hdr);
+                       fr_dbuff_out(&version_byte, &hdr_io);
+                       if (!version_byte) {
+                               version_byte = 0xc1; /* version 12.1 */
+                               fr_dbuff_set(&hdr_io, &hdr);
+                               fr_dbuff_in(&hdr_io, version_byte);
+                       }
                        /*
                         *      If the caller didn't set a session ID, use a random one.
                         */
@@ -612,7 +622,9 @@ ssize_t fr_tacacs_encode(fr_dbuff_t *dbuff, uint8_t const *original_packet, char
                         *      they have the correct values.
                         */
                        if (original) {
-                               if (!fr_dbuff_current(&hdr)[0]) {
+                               fr_dbuff_set(&hdr_io, &hdr);
+                               fr_dbuff_out(&version_byte, &hdr_io);
+                               if (!version_byte) {
                                        packet->hdr.version = original->version;
                                }