Use bounded string functions.

The bounds add a bit of safety in avoiding memory bugs and there are
sensible bounds in the cases we have been using them.

Change-Id: I381e122f356a54e5c0f1e183e521169522bc8aa9
diff --git a/test/linux/linux.c b/test/linux/linux.c
index d98d412..59e3ab9 100644
--- a/test/linux/linux.c
+++ b/test/linux/linux.c
@@ -78,7 +78,7 @@
 	int socket_id;
 	struct hf_sockaddr addr;
 	const char send_buf[] = "The quick brown fox jumps over the lazy dogs.";
-	size_t send_len = strlen(send_buf);
+	size_t send_len = sizeof(send_buf);
 	char resp_buf[MAX_BUF_SIZE];
 	ssize_t recv_len;