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@@ -0,0 +1,85 @@ +README +====== + +License: GPLv2 + +You should be able to find GNU Public License from www.gnu.org. + + +LSM is a Link Status Monitor which can be used to monitor +for example a Linux router/firewall connectivity and if +you happen to have multiple connections it can change +routing when an up/down event happens by utilizing external +script. + +When a SIGUSR1 is received current connection states are +syslogged. + +This package is highly influenced by fping and iputils arping. +Many thanks for their efforts. + + +TODO +==== + +- Add "odd" icmp packet handling (may not be necessary) +- You can't set source ip for ping packets. It's always + autodiscovered. +- Could the arping connection targets use only one socket ... +- IPv6 support. +- Should be able to check ENODEV somehow before first sendto. + Now exits with error code 2 after daemon which init-script + can't handle. + * This is now changed so that ENODEV causes LOG_ERR with each ping + but no exit and behave just as the packet was sent. So for ENODEV + you should get a down -event just as if there was packet loss. +- The source is kind of ugly ... + + +DECISION MAKING +=============== +As of lsm v0.27, the detection algorithm works like this: + +LSM keeps track of + 1) the result of the most recent pings (up to 100) + 2) the number of consecutive lost pings. + 3) the number of consecutive received pings. + +Let A == the number of recently lost pings +Let B == the number of consecutive lost pings +Let C == the number of consecutive returned pings + +If connection (or group) is UP + AND ( (A >= max_packet_loss) OR (B >= max_successive_pkts_lost) + then change the connection (or group) to down. + +Else If connection (or group) is DOWN + AND ( (A <= min_packet_loss) AND (C > min_successive_pkts_rcved) ) + then change the connection (or group) to up. + +Note: LSM assumes each connection starts UP. + + +DEPENDENCIES +============ + +default_script uses /bin/mail that's the only reason to depend on +mailx-package. + + +INSTALLING +========== + +There is now Makefile target install for those of you not using rpms. I use only +rpm based distros so that may not be in sync with lsm.spec which does all what +I need. + + +AUTHORS +======= + +Mika Ilmaranta <ilmis@nullnet.fi> + +See lsm.spec's changelog section for patch submitters. + +#EOF |