messages send by routers when they deny our traffic, this causes
a timeout when trying to connect to TCP ports/services on a remote
host, which is blocked by routers or firewalls.
rfc1122 (Requirements for Internet Hosts) section 3.2.2.1 actually
requi re that we treat such a message for a TCP session, that we
treat it like if we had recieved a RST.
quote begin.
A Destination Unreachable message that is received MUST be
reported to the transport layer. The transport layer SHOULD
use the information appropriately; for example, see Sections
4.1.3.3, 4.2.3.9, and 4.2.4 below. A transport protocol
that has its own mechanism for notifying the sender that a
port is unreachable (e.g., TCP, which sends RST segments)
MUST nevertheless accept an ICMP Port Unreachable for the
same purpose.
quote end.
I've written a small extension that implement this, it also create
a sysctl "net.inet.tcp.icmp_admin_prohib_like_rst" to control if
this new behaviour is activated.
When it's activated (set to 1) we'll treat a ICMP administratively
prohibited message (icmp type 3 code 9, 10 and 13) for a TCP
sessions, as if we recived a TCP RST, but only if the TCP session
is in SYN_SENT state.
The reason for only reacting when in SYN_SENT state, is that this
will solve the problem, and at the same time minimize the risk of
this being abused.
I suggest that we enable this new behaviour by default, but it
would be a change of current behaviour, so if people prefer to
leave it disabled by default, at least for now, this would be ok
for me, the attached diff actually have the sysctl set to 0 by
default.
PR: 23086
Submitted by: Jesper Skriver <jesper@skriver.dk>
1. ICMP ECHO and TSTAMP replies are now rate limited.
2. RSTs generated due to packets sent to open and unopen ports
are now limited by seperate counters.
3. Each rate limiting queue now has its own description, as
follows:
Limiting icmp unreach response from 439 to 200 packets per second
Limiting closed port RST response from 283 to 200 packets per second
Limiting open port RST response from 18724 to 200 packets per second
Limiting icmp ping response from 211 to 200 packets per second
Limiting icmp tstamp response from 394 to 200 packets per second
Submitted by: Mike Silbersack <silby@silby.com>
before adding/removing packets from the queue. Also, the if_obytes and
if_omcasts fields should only be manipulated under protection of the mutex.
IF_ENQUEUE, IF_PREPEND, and IF_DEQUEUE perform all necessary locking on
the queue. An IF_LOCK macro is provided, as well as the old (mutex-less)
versions of the macros in the form _IF_ENQUEUE, _IF_QFULL, for code which
needs them, but their use is discouraged.
Two new macros are introduced: IF_DRAIN() to drain a queue, and IF_HANDOFF,
which takes care of locking/enqueue, and also statistics updating/start
if necessary.
* Some dummynet code incorrectly handled a malloc()-allocated pseudo-mbuf
header structure, called "pkt," and could consequently pollute the mbuf
free list if it was ever passed to m_freem(). The fix involved passing not
pkt, but essentially pkt->m_next (which is a real mbuf) to the mbuf
utility routines.
* Also, for dummynet, in bdg_forward(), made the code copy the ethernet header
back into the mbuf (prepended) because the dummynet code that follows expects
it to be there but it is, unfortunately for dummynet, passed to bdg_forward
as a seperate argument.
PRs: kern/19551 ; misc/21534 ; kern/23010
Submitted by: Thomas Moestl <tmoestl@gmx.net>
Reviewed by: bmilekic
Approved by: luigi
instead.
Also, fix a small set of "avail." If we're setting `avail,' we shouldn't
be re-checking whether m_flags is M_EXT, because we know that it is, as if
it wasn't, we would have already returned several lines above.
Reviewed by: jlemon
only be checked if the system is currently performing New Reno style
fast recovery. However, this value was being checked regardless of the
NR state, with the end result being that the congestion window was never
opened.
Change the logic to check t_dupack instead; the only code path that
allows it to be nonzero at this point is NewReno, so if it is nonzero,
we are in fast recovery mode and should not touch the congestion window.
Tested by: phk
PPTP links are no longer dropped by simple (and inappropriate in this
case) "inactivity timeout" procedure, only when requested through the
control connection.
It is now possible to have multiple PPTP servers running behind NAT.
Just redirect the incoming TCP traffic to port 1723, everything else
is done transparently.
Problems were reported and the fix was tested by:
Michael Adler <Michael.Adler@compaq.com>,
David Andersen <dga@lcs.mit.edu>
<sys/proc.h> to <sys/systm.h>.
Correctly document the #includes needed in the manpage.
Add one now needed #include of <sys/systm.h>.
Remove the consequent 48 unused #includes of <sys/proc.h>.
because it only takes a struct tag which makes it impossible to
use unions, typedefs etc.
Define __offsetof() in <machine/ansi.h>
Define offsetof() in terms of __offsetof() in <stddef.h> and <sys/types.h>
Remove myriad of local offsetof() definitions.
Remove includes of <stddef.h> in kernel code.
NB: Kernelcode should *never* include from /usr/include !
Make <sys/queue.h> include <machine/ansi.h> to avoid polluting the API.
Deprecate <struct.h> with a warning. The warning turns into an error on
01-12-2000 and the file gets removed entirely on 01-01-2001.
Paritials reviews by: various.
Significant brucifications by: bde
of IP datagram. This fixes the problem when firewall denied fragmented
packets whose last fragment was less than minimum protocol header size.
Found by: Harti Brandt <brandt@fokus.gmd.de>
PR: kern/22309
in the code enforces this. So, do not check for and attempt a
false reassembly if only IP_RF is set.
Also, removed the dead code, since we no longer use dtom() on
return from ip_reass().
statistics on a per network address basis.
Teach the IPv4 and IPv6 input/output routines to log packets/bytes
against the network address connected to the flow.
Teach netstat to display the per-address stats for IP protocols
when 'netstat -i' is evoked, instead of displaying the per-interface
stats.
and instead reapply the revision 1.49 of mbuf.h, i.e.
Fixed regression of the type of the `header' member of struct pkthdr from
`void *' to caddr_t in rev.1.51. This mainly caused an annoying warning
for compiling ip_input.c.
Requested by: bde
enough into the mbuf data area. Solve this problem once and for all
by pulling up the entire (standard) header for TCP and UDP, and four
bytes of header for ICMP (enough for type, code and cksum fields).
the IP_FW_IF_IPID rule. (We have recently decided to keep the
ip_id field in network byte order inside the kernel, see revision
1.140 of src/sys/netinet/ip_input.c).
I did not like to have the conversion happen in userland, and I
think that the similar conversions for fw_tcp(seq|ack|win) should
be moved out of userland (src/sbin/ipfw/ipfw.c) into the kernel.
