tls: code shrink

function                                             old     new   delta
tls_get_zeroed_outbuf                                  -      28     +28
static.empty_client_cert                               7       -      -7
tls_handshake                                       1930    1890     -40
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/1 up/down: 28/-47)            Total: -19 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/networking/tls.c b/networking/tls.c
index 20343bc0a..90a1bcf35 100644
--- a/networking/tls.c
+++ b/networking/tls.c
@@ -602,6 +602,13 @@ static void *tls_get_outbuf(tls_state_t *tls, int len)
         return tls->outbuf + OUTBUF_PFX;
 }
 
+static void *tls_get_zeroed_outbuf(tls_state_t *tls, int len)
+{
+        void *record = tls_get_outbuf(tls, len);
+        memset(record, 0, len);
+        return record;
+}
+
 static void xwrite_encrypted(tls_state_t *tls, unsigned size, unsigned type)
 {
         uint8_t *buf = tls->outbuf + OUTBUF_PFX;
@@ -1332,8 +1339,7 @@ static void send_client_hello_and_alloc_hsd(tls_state_t *tls, const char *sni)
 
         /* +2 is for "len of all extensions" 2-byte field */
         len = sizeof(*record) + 2 + ext_len;
-        record = tls_get_outbuf(tls, len);
-        memset(record, 0, len);
+        record = tls_get_zeroed_outbuf(tls, len);
 
         fill_handshake_record_hdr(record, HANDSHAKE_CLIENT_HELLO, len);
         record->proto_maj = TLS_MAJ;    /* the "requested" version of the protocol, */
@@ -1565,19 +1571,15 @@ static void send_empty_client_cert(tls_state_t *tls)
                 uint8_t cert_chain_len24_hi, cert_chain_len24_mid, cert_chain_len24_lo;
         };
         struct client_empty_cert *record;
-        static const uint8_t empty_client_cert[] = {
-                HANDSHAKE_CERTIFICATE,
-                0, 0, 3, //len24
-                0, 0, 0, //cert_chain_len24
-        };
 
-        record = tls_get_outbuf(tls, sizeof(*record));
+        record = tls_get_zeroed_outbuf(tls, sizeof(*record));
         //fill_handshake_record_hdr(record, HANDSHAKE_CERTIFICATE, sizeof(*record));
         //record->cert_chain_len24_hi = 0;
         //record->cert_chain_len24_mid = 0;
         //record->cert_chain_len24_lo = 0;
         // same as above:
-        memcpy(record, empty_client_cert, sizeof(empty_client_cert));
+        record->type = HANDSHAKE_CERTIFICATE;
+        record->len24_lo = 3;
 
         dbg(">> CERTIFICATE\n");
         xwrite_and_update_handshake_hash(tls, sizeof(*record));
@@ -1591,7 +1593,7 @@ static void send_client_key_exchange(tls_state_t *tls)
                 uint8_t key[2 + 4 * 1024]; // size??
         };
 //FIXME: better size estimate
-        struct client_key_exchange *record = tls_get_outbuf(tls, sizeof(*record));
+        struct client_key_exchange *record = tls_get_zeroed_outbuf(tls, sizeof(*record));
         uint8_t rsa_premaster[RSA_PREMASTER_SIZE];
         uint8_t x25519_premaster[CURVE25519_KEYSIZE];
         uint8_t *premaster;
@@ -1646,7 +1648,7 @@ static void send_client_key_exchange(tls_state_t *tls)
         }
 
         record->type = HANDSHAKE_CLIENT_KEY_EXCHANGE;
-        record->len24_hi  = 0;
+        /* record->len24_hi = 0; - already is */
         record->len24_mid = len >> 8;
         record->len24_lo  = len & 0xff;
         len += 4;