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Logging GI-Addr
I've spent a little bit trying to find how to log things - specifically the GI-Addr.
But digging down through the log (priority, data-expr) is not exactly easy. [In fact, I'm not sure the GI-Addr information will be in there...]
And my GoogleFoo isn't getting me much that's helpful either.
Can someone give me a quick recipe that will help point me in the right direction?
I'll keep looking at the docs and seeing what I can further google up, but I'm feeling lost. :)
-Greg
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" GIaddr:",
pick-first-value(binary-to-ascii(10, 8, ".", packet(24,4)),
"(none)")
Bill
On 2/11/2018 11:06 PM, Gregory Sloop
wrote:
Logging GI-Addr
I've
spent a little bit trying to find how to log things -
specifically the GI-Addr.
But digging down through the log (priority, data-expr) is not
exactly easy. [In fact, I'm not sure the GI-Addr information
will be in there...]
And my GoogleFoo isn't getting me much that's helpful either.
Can someone give me a quick recipe that will help point me in
the right direction?
I'll keep looking at the docs and seeing what I can further
google up, but I'm feeling lost. :)
-Greg
_______________________________________________
dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
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dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
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Re: Logging GI-Addr
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" GIaddr:", pick-first-value(binary-to-ascii(10, 8, ".", packet(24,4)), "(none)") |
So, let me break this down, and see if I understand it correctly.
Starting from the inside...
Offset into the packet 24 bytes, and return 4 bytes [4 octets].
---
I think this means that the OP, HType, HLen and HOPS, [4 bytes / 1 octet [each] *4]
XID [4 octets / 4 bytes]
SECs and FLAGs [4 bytes, 2 octets each*2]
Then continue to offset past the CIADDR, YADDR & SIADDR (Four octets, 4 bytes each in IPV4) to get to the GIAddr, at byte 24.
Grab 4 bytes, 4 octets
[The wikipedia page on dhcp is pretty handy here! https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol ]
---
Convert from binary to ASCII from base 8 to base 10. Separate the items with "."
Grab the first non-null output from that output of binary-to-ascii.
If there's no GIAddr in this packet, return "(none)"
Do I have that right?
Thanks so much!
-Greg
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Yes, that is correct. Insert that line in with the rest of your
logging.
on commit {
log (
info,
concat (
"Host:", pick-first-value(option
fqdn.hostname, option host-name, "(none)"), "=>",
pick-first-value(config-option server.ddns-hostname, "(none)")
...
," GIaddr:",
pick-first-value(binary-to-ascii(10, 8, ".", packet(24,4)),
"(none)")
# ," Circuit:", pick-first-value(binary-to-ascii(10,
8, ":", option agent.circuit-id), "(none)")
# ," Remote:", pick-first-value(option
agent.remote-id, "(none)")
," ReqOpt:", pick-first-value(binary-to-ascii(10,
8, ",", option dhcp-parameter-request-list), "(none)")
)
);
}
Bill
On 2/12/2018 5:35 PM, Gregory Sloop
wrote:
Re: Logging GI-Addr
|
" GIaddr:",
pick-first-value(binary-to-ascii(10, 8, ".",
packet(24,4)), "(none)") |
So, let
me break this down, and see if I understand it correctly.
Starting from the inside...
Offset into the packet 24 bytes, and return 4 bytes [4 octets].
---
I think this means that the OP, HType, HLen and HOPS, [4 bytes
/ 1 octet [each] *4]
XID [4 octets / 4 bytes]
SECs and FLAGs [4 bytes, 2 octets each*2]
Then continue to offset past the CIADDR, YADDR & SIADDR
(Four octets, 4 bytes each in IPV4) to get to the GIAddr, at
byte 24.
Grab 4 bytes, 4 octets
[The wikipedia page on dhcp is pretty handy here! https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol ]
---
Convert from binary to ASCII from base 8 to base 10. Separate
the items with "."
Grab the first non-null output from that output of
binary-to-ascii.
If there's no GIAddr in this packet, return "(none)"
Do I have that right?
Thanks so much!
-Greg
_______________________________________________
dhcp-users mailing list
[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
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[hidden email]
https://lists.isc.org/mailman/listinfo/dhcp-users
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