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| author | Francis Dupont <fdupont@isc.org> | 2019-12-10 19:37:22 +0100 |
|---|---|---|
| committer | Francis Dupont <fdupont@isc.org> | 2019-12-10 21:05:02 +0100 |
| commit | b1fb6811ffe149c375a4503d2d64604acae72f83 (patch) | |
| tree | 85b6502239e352eb6c0d73ef12b03519029ceb73 /src/lib/dhcpsrv/database_backends.dox | |
| parent | [897-add-infinite-valid-lifetime-for-bootp] Added comments about T1/T2 vs inf... (diff) | |
| download | kea-b1fb6811ffe149c375a4503d2d64604acae72f83.tar.xz kea-b1fb6811ffe149c375a4503d2d64604acae72f83.zip | |
[#897] Addressed comments
Diffstat (limited to 'src/lib/dhcpsrv/database_backends.dox')
| -rw-r--r-- | src/lib/dhcpsrv/database_backends.dox | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/src/lib/dhcpsrv/database_backends.dox b/src/lib/dhcpsrv/database_backends.dox index e7019accd6..9f0bcffe13 100644 --- a/src/lib/dhcpsrv/database_backends.dox +++ b/src/lib/dhcpsrv/database_backends.dox @@ -105,6 +105,23 @@ For details, see @ref isc::db::CqlConnection::openDatabase(). + @subsection infinite-valid-lifetime Infinite Valid Lifetime + + The @c isc::dhcp::Lease class uses cltt (client last transmission time) + and valid lifetime, backend lease uses expire and valid lifetime. + These quantities are bound by the equation: + @code + expire = cltt + valid_lifetime + @endcode + + But when expire is a 32 bit date and valid lifetime is the infinity + special value (0xffffffff) this overflows so for MySQL and PostgreSQL + backends this becomes: + @code + expire = cltt + valid_lifetime if valid_lifetime != 0xffffffff + expire = cltt if valid_lifetime == 0xffffffff + @endcode + @section dhcpdb-host Host Backends Host backends (known also as host data sources) are similar to lease |