30 lines
1.3 KiB
Markdown
30 lines
1.3 KiB
Markdown
DLT and LINKTYPE allocation
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===========================
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DLT_ types live in pcap/dlt.h. They can be requested by the community on a
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First-Come First-Served basis [i.e. https://tools.ietf.org/html/rfc8126#section-4.4 ]
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(Although libpcap is not at this time an IETF specification, there have been
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some as yet-incomplete efforts to do this).
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The Tcpdump Group prefers to link to an open specification on the new DLT_
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type, but they are available for closed, proprietary projects as well.
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In that case, a stable email address suffices so that someone who finds
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an unknown DLT_ type can investigate.
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We prefer to give out unambiguous numbers, and we try to do it as quickly
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as possible, but DLT_USERx is available while you wait.
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Note that DLT_ types are, in theory, private to the capture mechanism and can
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in some cases be operating system specific, and so a second set of values,
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LINKTYPE_ is allocated for actually writing to pcap files. As much as
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possible going forward, the DLT_ and LINKTYPE_ value are identical, however,
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this was not always the case. See pcap-common.c.
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The LINKTYPE_ values are not exported, but are in pcap-common.c only.
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DEVELOPER NOTES
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---------------
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When allocating a new DLT_ value, a corresponding value needs to be
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added to pcap-common.c.
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It is not necessary to copy the comments from dlt.h to pcap-common.c.
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