Revert "apply onetime auth to the first packet"

This reverts commit 889e4b96a1.

src/local.c

@@ -473,6 +473,8 @@ static void server_recv_cb(EV_P_ ev_io *w, int revents)
                 if (!remote->direct) {
                     if (auth) {
                         ss_addr_to_send[0] |= ONETIMEAUTH_FLAG;
+                        ss_onetimeauth(ss_addr_to_send + addr_len, ss_addr_to_send, addr_len);
+                        addr_len += ONETIMEAUTH_BYTES;
                     }
 
                     memcpy(remote->buf, ss_addr_to_send, addr_len);
@@ -480,12 +482,6 @@ static void server_recv_cb(EV_P_ ev_io *w, int revents)
                         memcpy(remote->buf + addr_len, buf, r);
                     }
                     r += addr_len;
-
-                    if (auth) {
-                        ss_onetimeauth(remote->buf + r, remote->buf, r);
-                        r += ONETIMEAUTH_BYTES;
-                    }
-
                 } else {
                     if (r > 0) {
                         memcpy(remote->buf, buf, r);

src/server.c

@@ -641,13 +641,13 @@ static void server_recv_cb(EV_P_ ev_io *w, int revents)
         offset += 2;
 
         if (auth || (atyp & ONETIMEAUTH_MASK)) {
-            r -= ONETIMEAUTH_BYTES;
-            if (ss_onetimeauth_verify(server->buf + r, server->buf, r)) {
+            if (ss_onetimeauth_verify(server->buf + offset, server->buf, offset)) {
                 LOGE("authentication error %d", atyp);
                 report_addr(server->fd);
                 close_and_free_server(EV_A_ server);
                 return;
             };
+            offset += ONETIMEAUTH_BYTES;
         }
 
         if (verbose) {