diff --git a/ggatec/ggatec.c b/ggatec/ggatec.c
index 3ca77eb..7e1027e 100644
--- a/ggatec/ggatec.c
+++ b/ggatec/ggatec.c
@@ -95,10 +95,14 @@ send_thread(void *arg __unused)
 {
 	struct g_gate_ctl_io ggio;
 	struct g_gate_hdr hdr;
-	char buf[MAXPHYS];
+	static char *buf;
 	ssize_t data;
+	int buflen = 1024*1024;
 	int error;
 
+	if (buf == NULL)
+		buf = malloc(buflen);
+
 	g_gate_log(LOG_NOTICE, "%s: started!", __func__);
 
 	ggio.gctl_version = G_GATE_VERSION;
@@ -106,7 +110,7 @@ send_thread(void *arg __unused)
 	ggio.gctl_data = buf;
 
 	for (;;) {
-		ggio.gctl_length = sizeof(buf);
+		ggio.gctl_length = buflen;
 		ggio.gctl_error = 0;
 		g_gate_ioctl(G_GATE_CMD_START, &ggio);
 		error = ggio.gctl_error;
@@ -203,9 +207,14 @@ recv_thread(void *arg __unused)
 {
 	struct g_gate_ctl_io ggio;
 	struct g_gate_hdr hdr;
-	char buf[MAXPHYS];
+	static char *buf;
+	int buflen;
 	ssize_t data;
 
+	buflen = 1024*1024;
+	if (buf == NULL)
+		buf = malloc(buflen);
+
 	g_gate_log(LOG_NOTICE, "%s: started!", __func__);
 
 	ggio.gctl_version = G_GATE_VERSION;
@@ -233,6 +242,13 @@ recv_thread(void *arg __unused)
 		ggio.gctl_length = hdr.gh_length;
 		ggio.gctl_error = hdr.gh_error;
 
+		if (ggio.gctl_length > buflen) {
+			g_gate_log(LOG_ERR, "Received too large data, %llu.", ggio.gctl_length);
+			reconnect = 1;
+			pthread_kill(sendtd, SIGUSR1);
+			break;
+		}
+
 		if (ggio.gctl_error == 0 && ggio.gctl_cmd == GGATE_CMD_READ) {
 			data = g_gate_recv(recvfd, ggio.gctl_data,
 			    ggio.gctl_length, MSG_WAITALL);