From 43021b31005abe90cf69cf5b3ed90053bf08adf2 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 28 Jan 2021 11:13:18 +0000
Subject: [PATCH] client: Add some example for gathering random data

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/client.c | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/client.c b/src/client.c
index f1bc97f..cc9fd44 100644
--- a/src/client.c
+++ b/src/client.c
@@ -20,8 +20,9 @@
 
 #include <errno.h>
 #include <signal.h>
-#include <sys/epoll.h>
 #include <string.h>
+#include <sys/epoll.h>
+#include <sys/random.h>
 #include <unistd.h>
 
 #include "client.h"
@@ -60,8 +61,22 @@ static int connect_socket(struct fireperf_config* conf, int fd) {
 	return 0;
 }
 
-static void randomize_buffer(char* buffer, size_t s) {
-	return; // TODO
+/*
+	This is just an example implementation because getrandom() is too slow for
+	this purpose. I would need a really fast pseudo-RNG.
+*/
+static int randomize_buffer(char* buffer, size_t s) {
+	ssize_t r = getrandom(buffer, s, 0);
+
+	// Error
+	if (r < 0)
+		return 1;
+
+	// We received less data than we wanted
+	else if (r > 0 && (size_t)r < s)
+		return 1;
+
+	return 0;
 }
 
 static int send_data_to_server(struct fireperf_config* conf, int fd) {
@@ -72,7 +87,12 @@ static int send_data_to_server(struct fireperf_config* conf, int fd) {
 
 	// Randomize the buffer if requested, otherwise just send an empty buffer
 	if (!conf->zero) {
-		randomize_buffer(buffer, sizeof(buffer));
+		int r = randomize_buffer(buffer, sizeof(buffer));
+		if (r) {
+			ERROR(conf, "Could not generate a random block of data: %s\n",
+				strerror(errno));
+			return 1;
+		}
 	}
 
 	do {
-- 
2.47.3