Module: monitoring-plugins Branch: master Commit: 8672529b37fc73fbcc15cb2b2ba9b677f37dac5e Author: Holger Weiss <hol...@zedat.fu-berlin.de> Date: Fri Sep 16 09:43:04 2016 +0200 URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=8672529
check_dhcp: Make xid a bit more random Don't just use the current time(2) to seed the PRNG that generates the xid. A DHCP server might be checked multiple times per second. --- plugins-root/check_dhcp.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/plugins-root/check_dhcp.c b/plugins-root/check_dhcp.c index 445ddbc..88b7ca1 100644 --- a/plugins-root/check_dhcp.c +++ b/plugins-root/check_dhcp.c @@ -463,10 +463,9 @@ int send_dhcp_discover(int sock){ discover_packet.hlen=ETHERNET_HARDWARE_ADDRESS_LENGTH; /* - * transaction ID is supposed to be random. We won't use the address so - * we don't care about high entropy here. time(2) is good enough. + * transaction ID is supposed to be random. */ - srand(time(NULL)); + srand(time(NULL)^getpid()); packet_xid=random(); discover_packet.xid=htonl(packet_xid);