handshake: support extracting record size limit value

src/tlshd/handshake.c

@@ -80,6 +80,7 @@ static void tlshd_save_nagle(gnutls_session_t session, int *saved)
 void tlshd_start_tls_handshake(gnutls_session_t session,
 			       struct tlshd_handshake_parms *parms)
 {
+	ssize_t record_size_limit;
 	int saved, ret;
 	char *desc;
 
@@ -112,6 +113,11 @@ void tlshd_start_tls_handshake(gnutls_session_t session,
 	gnutls_free(desc);
 
 	parms->session_status = tlshd_initialize_ktls(session);
+	record_size_limit = gnutls_record_get_record_size_limit(session);
+	if (record_size_limit <= 0)
+		tlshd_log_notice("Inavlid Record size limit: %zd\n", record_size_limit);
+	else
+		parms->record_size_limit = (uint32_t)record_size_limit;
 }
 
 /**

src/tlshd/netlink.c

@@ -331,6 +331,7 @@ static const struct tlshd_handshake_parms tlshd_default_handshake_parms = {
 	.peerids		= NULL,
 	.remote_peerids		= NULL,
 	.msg_status		= 0,
+	.record_size_limit	= 0,
 	.session_status		= EIO,
 };
 
@@ -505,6 +506,12 @@ void tlshd_genl_done(struct tlshd_handshake_parms *parms)
 	if (err < 0)
 		goto out_free;
 
+	err = nla_put_u32(msg, HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT, parms->record_size_limit);
+	if (err < 0) {
+		tlshd_log_nl_error("nla_put record_size_limit", err);
+		goto out_free;
+	}
+
 sendit:
 	if (tlshd_delay_done) {
 		/* Undocumented tlshd.conf parameter:

src/tlshd/netlink.h

@@ -55,6 +55,7 @@ enum {
 	HANDSHAKE_A_DONE_STATUS = 1,
 	HANDSHAKE_A_DONE_SOCKFD,
 	HANDSHAKE_A_DONE_REMOTE_AUTH,
+	HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
 
 	__HANDSHAKE_A_DONE_MAX,
 	HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)

src/tlshd/tlshd.h

@@ -41,6 +41,7 @@ struct tlshd_handshake_parms {
 	GArray		*peerids;
 	GArray		*remote_peerids;
 	int		msg_status;
+	uint32_t        record_size_limit;
 
 	unsigned int	session_status;
 };