Kernel netdump project

Status: Committed to SVN in r333283 and nearby commits.

Netdump provides kernel core dumping over the network, instead of to a local disk. It implements a very minimal UDP/IPv4 stack and uses a custom UDP protocol to transmit the dump to the netdump server running on another host.

Netdump should find use in diskless workstation clusters, PXE-booted test machines, and perhaps when doing disk driver development.

• https://web.archive.org/web/20040619062455/www.cs.duke.edu/~anderson/freebsd/netdump/readme.html

• Netdump is fairly inefficient in the face of packet loss. When it misses an ACK, it prints “. ”.
• Netdumpd names cores based on source IP (“vmcore-IP.num”) but decryptcore(8) expects a certain convention

• Fixing any NIC-specific netdump bugs as they crop up
• Validate EKCD + netdumps (CEM: I've done some preliminary testing here and it mostly seems to work. The integration needs a little polish.)
  • (EKCD provides dump privacy, but not integrity nor does it authenticate the client to the server.)
• Validate compression + netdump (CEM: I've done some preliminary testing here too and it seems ok. Ditto maybe needing polish.)
• Improve performance. Current protocol is not ideal.
• Investigate using a standard protocol (TFTP?)
• Handling changing server domain IPs, interface IPs, and routes in some general fashion.
  • DNS resolution at dump time rather than configuration time?
    • Similar class of issue handling changing resolv.conf list
• IPv6 support
  • L2 address resolution using NDP instead of ARP
  • Something about SLAAC to auto-configure?
• Client authentication to netdumpd, i.e., solving the netdumpd trivial DoS problem
• Multiple servers (fallback?)

netdump(4) dumpon(8)

• Mark Johnston