CVS commit: src/sys/netinet

["Ryota Ozaki" <ozaki-r%netbsd.org@localhost>]

Module Name:    src
Committed By:   ozaki-r
Date:           Tue Jun 17 04:23:57 UTC 2025

Modified Files:
        src/sys/netinet: ip_input.c

Log Message:
in: avoid packet looping on incoming packets destining to an initializing address

The initialization of an IPv4 address is done by adding a connected route and
a local route (if necessary), and then publishing itself by adding it to the
global list (and the global hashtable).  Thus, there can exist a route with an
address that is not published.  This inconsistent state allows an incoming
packet destining to one of a host address which is not published but has a
local route to be forwarded and routed to a loopback interface.  This results
in forwarding the packet back to ip_input, that is, packet looping.

To avoid the situation, prohibit packets being forwarded via a local route.

This is a workaround for "IPv4 address initialization atomicity" in doc/TODO.smpnet.


To generate a diff of this commit:
cvs rdiff -u -r1.404 -r1.405 src/sys/netinet/ip_input.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.