While here fix ipv6 pcb printing by making tcp6_dump with tcp.
XXX: Merge the inet and the inet6 code. It is silly to need to specify
-p tcp6 to print a tcp6 pcb, we already know what it is.
- introduce a limit for the routes accepted via IPv6 Router Advertisement:
a common 2 interface client will have 6, the default limit is 100 and
can be adjusted via sysctl
- report the current number of routes installed via RA via sysctl
- count discarded route additions. Note that one RA message is two routes.
This is at present only across all interfaces even though per-interface
would be more useful, since the per-interface structure complies to RFC2466
- bump kernel version due to the previous change
- adjust netstat to use the new value (with netstat -p icmp6)
methods called Vestigial Time-Wait (VTW) and Maximum Segment Lifetime
Truncation (MSLT).
MSLT and VTW were contributed by Coyote Point Systems, Inc.
Even after a TCP session enters the TIME_WAIT state, its corresponding
socket and protocol control blocks (PCBs) stick around until the TCP
Maximum Segment Lifetime (MSL) expires. On a host whose workload
necessarily creates and closes down many TCP sockets, the sockets & PCBs
for TCP sessions in TIME_WAIT state amount to many megabytes of dead
weight in RAM.
Maximum Segment Lifetimes Truncation (MSLT) assigns each TCP session to
a class based on the nearness of the peer. Corresponding to each class
is an MSL, and a session uses the MSL of its class. The classes are
loopback (local host equals remote host), local (local host and remote
host are on the same link/subnet), and remote (local host and remote
host communicate via one or more gateways). Classes corresponding to
nearer peers have lower MSLs by default: 2 seconds for loopback, 10
seconds for local, 60 seconds for remote. Loopback and local sessions
expire more quickly when MSLT is used.
Vestigial Time-Wait (VTW) replaces a TIME_WAIT session's PCB/socket
dead weight with a compact representation of the session, called a
"vestigial PCB". VTW data structures are designed to be very fast and
memory-efficient: for fast insertion and lookup of vestigial PCBs,
the PCBs are stored in a hash table that is designed to minimize the
number of cacheline visits per lookup/insertion. The memory both
for vestigial PCBs and for elements of the PCB hashtable come from
fixed-size pools, and linked data structures exploit this to conserve
memory by representing references with a narrow index/offset from the
start of a pool instead of a pointer. When space for new vestigial PCBs
runs out, VTW makes room by discarding old vestigial PCBs, oldest first.
VTW cooperates with MSLT.
It may help to think of VTW as a "FIN cache" by analogy to the SYN
cache.
A 2.8-GHz Pentium 4 running a test workload that creates TIME_WAIT
sessions as fast as it can is approximately 17% idle when VTW is active
versus 0% idle when VTW is inactive. It has 103 megabytes more free RAM
when VTW is active (approximately 64k vestigial PCBs are created) than
when it is inactive.
use only sysctl and no kvm (implementing /dev/mem for a rump kernel
would probably not be hard, but still a non-zero effort).
Note: since there is absolutely no network activity in a fresh rump
kernel, rump.netstat usually displays exactly nothing when invoked
without parameters. Arguments like -r, -bi, -p icmp etc. produce
more stuff.
listener sockets unless -a was given. (It was checking the local
address instead of the remote address for being INADDR_ANY or
equivalent.)
PR 38093 from Dieter Roelants; I adjusted the patch a little.
This needs pullups for both -4 and -5.
Heavily based on similar code from Claudio Jeker (at OpenBSD).
While here, fix inet/inet6 sysctl stuff commited previously to
actually work, and some other nits to make netstat more sysctl
friendly.
One step closer to losing setgid kmem on this one...
christos