When BGP routes are missing, DHCP packets get relayed over mgmt
interface. This results in dhcpmon alerting that DHCP packets are
not being relayed. This is PR include mgmt interface as uplink
device, and so, if DHCP packet gets relayed over mgmt interface,
regular dhcpmon alert will not be issues. Instead, dhcpmon will
check the mgmt interface counts and issue a separate alert regarding
packets travelling through mgmt network.
In addition, this PR includes the following enhancements:
1. Add SIGUSR1 handler that prints out current packet counts
2. Increase alert grace window to 3 minutes from currently 2 minutes
3. Time is now computed more accurately
4. Print vlan name before counters
signed-off-by: Tamer Ahmed <tamer.ahmed@microsoft.com>
* [dhcp-relay]: Add DHCP Relay Monitor (#3886)
DHCP relay MONitor (dhcpmon) keeps track of DORA messages. If DHCP Relay
is detected to be not forwarding DORA message, dhcpmon will log such event
to syslog. Under the hood dhcpmon keeps counts of clients DR messages,
forwarded DR messages, DHCP server OA messages, and forwarded OA messages.
dhcpmon will check every 12 sec (configurable) if counts are monotonically
increasing and record snapshot of those counters. dhcpmon will report
discrepancies when detected between current counters and snapshot counters.
pull-request: https://github.com/Azure/sonic-buildimage/pull/3886
signed-off-by: Tamer Ahmed <tamer.ahmed@microsoft.com>
* Eliminate dependency on libexplain
* Remove dependency on libexplain
* Change URL for isc-dhcp source repository
* Modify supervisor conf to generate dhcrelay commands with '-id' and '-iu' options
* Comments; Also clean up jinja2 syntax
* Patch relay to open one socket per interface and send to all servers on all upstream interfaces
* Patch relay agent to properly forward BOOTREQUEST only on appropriate interface if it is a directed broadcast
* Port upstream patches to isc-dhcp-relay to support upstream/downstream interfaces
* Update patch to properly support interfaces with multiple IP addresses assigned
* Pass --enable-use-sockets to configure instead of uncommenting USE_SOCKETS directly
* [DHCP Relay]: Support new <DhcpRelays> minigraph tag; support multiple VLANs
* Don't start dhcrelay in quiet mode so as to get startup output in syslog
* Update sonic-cfggen tests to support new '<DhcpRelays>' tag
* <DhcpRelays> tag is only present for VLANs which require a DHCP relay agent -- only parse if present
* Don't attempt to configure a DHCP relay agent for VLANs without specified DHCP servers
* Modify to work with Taoyu's minigraph/DB changes (#942)
* Reduce number of DHCP servers in sonic-cfggen unit tests from 4 to 2
* Remove isc-dhcp-relay sample output file from sonic-cfggen test, as we no longer generate that file
* Update Option 82 isc-dhcp-relay patch to load all interface name-alias maps into memory once at start instead of calling sonic-cfggen on each packet we relay
* Remove executable permission from Jinja2 template
* Set max hop count to 1 so that DHCP relay will only relay packets with a hop count of zero
* Replace tabs with spaces
* Modify overlooked sonic-cfggen call, use Config DB instead of minigraph
* Also ensure > 1 VLAN requires a DHCP relay agent before outputting to template
* Generate port name-alias map file using sonic-cfggen and parse that in lieu of parsing port_config.ini directly
* No longer drop packets with hop count > 0; Instead, drop packets which already contain agent info
