functionality:
- Remove a rwlock aquisition/release per generated syncookie. Locking
is now integrated with the bucket row locking of syncache itself and
syncookies no longer add any additional lock overhead.
- Syncookie secrets are different for and stored per syncache buck row.
Secrets expire after 16 seconds and are reseeded on-demand.
- The computational overhead for syncookie generation and verification
is one MD5 hash computation as before.
- Syncache can be turned off and run with syncookies only by setting the
sysctl net.inet.tcp.syncookies_only=1.
This implementation extends the orginal idea and first implementation
of FreeBSD by using not only the initial sequence number field to store
information but also the timestamp field if present. This way we can
keep track of the entire state we need to know to recreate the session in
its original form. Almost all TCP speakers implement RFC1323 timestamps
these days. For those that do not we still have to live with the known
shortcomings of the ISN only SYN cookies. The use of the timestamp field
causes the timestamps to be randomized if syncookies are enabled.
The idea of SYN cookies is to encode and include all necessary information
about the connection setup state within the SYN-ACK we send back and thus
to get along without keeping any local state until the ACK to the SYN-ACK
arrives (if ever). Everything we need to know should be available from
the information we encoded in the SYN-ACK.
A detailed description of the inner working of the syncookies mechanism
is included in the comments in tcp_syncache.c.
Reviewed by: silby (slightly earlier version)
Sponsored by: TCP/IP Optimization Fundraise 2005
exists to allow the mandatory access control policy to properly initialize
mbufs generated by the firewall. An example where this might happen is keep
alive packets, or ICMP error packets in response to other packets.
This takes care of kernel panics associated with un-initialize mbuf labels
when the firewall generates packets.
[1] I modified this patch from it's original version, the initial patch
introduced a number of entry points which were programmatically
equivalent. So I introduced only one. Instead, we should leverage
mac_create_mbuf_netlayer() which is used for similar situations,
an example being icmp_error()
This will minimize the impact associated with the MFC
Submitted by: mlaier [1]
MFC after: 1 week
This is a RELENG_6 candidate
validity of ro->ro_rt first. This prevents crashing on any non-normally
routed IP packet.
Coverity CID: 162 (incorrectly, it was re-introduced by previous commit)
support a network w/ split mtu's by assigning each host route the correct
mtu. an aspiring programmer could write a daemon to probe hosts and find
out if they support a larger mtu.
timeouts for TCP and T/TCP connections in the TIME_WAIT
state, and we had two separate timed wait queues for them.
Now that is has gone, the timeout is always 2*MSL again,
and there is no reason to keep two queues (the first was
unused anyway!).
Also, reimplement the remaining queue using a TAILQ (it
was technically impossible before, with two queues).
TSO is only used if we are in a pure bulk sending state. The presence of
TCP-MD5, SACK retransmits, SACK advertizements, IPSEC and IP options prevent
using TSO. With TSO the TCP header is the same (except for the sequence number)
for all generated packets. This makes it impossible to transmit any options
which vary per generated segment or packet.
The length of TSO bursts is limited to TCP_MAXWIN.
The sysctl net.inet.tcp.tso globally controls the use of TSO and is enabled.
TSO enabled sends originating from tcp_output() have the CSUM_TCP and CSUM_TSO
flags set, m_pkthdr.csum_data filled with the header pseudo-checksum and
m_pkthdr.tso_segsz set to the segment size (net payload size, not counting
IP+TCP headers or TCP options).
IPv6 currently lacks a pseudo-header checksum function and thus doesn't support
TSO yet.
Tested by: Jack Vogel <jfvogel-at-gmail.com>
Sponsored by: TCP/IP Optimization Fundraise 2005
o add IFCAP_TSO[46] for drivers to announce this capability for IPv4 and IPv6
o add CSUM_TSO flag to mbuf pkthdr csum_flags field
o add tso_segsz field to mbuf pkthdr
o enhance ip_output() packet length check to allow for large TSO packets
o extend tcp_maxmtu[46]() with a flag pointer to pass interface capabilities
o adjust all callers of tcp_maxmtu[46]() accordingly
Discussed on: -current, -net
Sponsored by: TCP/IP Optimization Fundraise 2005
and skip over the normal IP processing.
Add a supporting function ifa_ifwithbroadaddr() to verify and validate the
supplied subnet broadcast address.
PR: kern/99558
Tested by: Andrey V. Elsukov <bu7cher-at-yandex.ru>
Sponsored by: TCP/IP Optimization Fundraise 2005
MFC after: 3 days
bad under high load. For example with 40k sockets and 25k tcptw
entries, connect() syscall can run for seconds. Debugging showed
that it iterates the cycle millions times and purges thousands of
tcptw entries at a time.
Besides practical unusability this change is architecturally
wrong. First, in_pcblookup_local() is used in connect() and bind()
syscalls. No stale entries purging shouldn't be done here. Second,
it is a layering violation.
o Return back the tcptw purging cycle to tcp_timer_2msl_tw(),
that was removed in rev. 1.78 by rwatson. The commit log of this
revision tells nothing about the reason cycle was removed. Now
we need this cycle, since major cleaner of stale tcptw structures
is removed.
o Disable probably necessary, but now unused
tcp_twrecycleable() function.
Reviewed by: ru
for example:
fwd tablearg ip from any to table(1)
where table 1 has entries of the form:
1.1.1.0/24 10.2.3.4
208.23.2.0/24 router2
This allows trivial implementation of a secondary routing table implemented
in the firewall layer.
I expect more work (under discussion with Glebius) to follow this to clean
up some of the messy parts of ipfw related to tables.
Reviewed by: Glebius
MFC after: 1 month
in older versions of FreeBSD. This option is pointless as it is needed in just
about every interesting usage of forward that I have ever seen. It doesn't make
the system any safer and just wastes huge amounts of develper time
when the system doesn't behave as expected when code is moved from
4.x to 6.x It doesn't make
the system any safer and just wastes huge amounts of develper time
when the system doesn't behave as expected when code is moved from
4.x to 6.x or 7.x
Reviewed by: glebius
MFC after: 1 week
were unused or already in if_var.h so add if_name() to if_var.h and
remove net_osdep.h along with all references to it.
Longer term we may want to kill off if_name() entierly since all modern
BSDs have if_xname variables rendering it unnecessicary.
tcp_twstart(), but not to the other, tcp_detach(), as the socket is
already being torn down and therefore there are no listeners. This avoids
a panic if kqueue state is registered on the socket at close(), and
eliminates to XXX comments. There is one case remaining in which
tcp_discardcb() reaches up to the socket layer as part of the TCP host
cache, which would be good to avoid.
Reported by: Goran Gajic <ggajic at afrodita dot rcub dot bg dot ac dot yu>
function, pru_close, to notify protocols that the file descriptor or
other consumer of a socket is closing the socket. pru_abort is now a
notification of close also, and no longer detaches. pru_detach is no
longer used to notify of close, and will be called during socket
tear-down by sofree() when all references to a socket evaporate after
an earlier call to abort or close the socket. This means detach is now
an unconditional teardown of a socket, whereas previously sockets could
persist after detach of the protocol retained a reference.
This faciliates sharing mutexes between layers of the network stack as
the mutex is required during the checking and removal of references at
the head of sofree(). With this change, pru_detach can now assume that
the mutex will no longer be required by the socket layer after
completion, whereas before this was not necessarily true.
Reviewed by: gnn
( and where appropriate the destruction) of the pcb mutex to the init/finit
functions of the pcb zones.
This allows locking of the pcb entries and race condition free comparison
of the generation count.
Rearrange locking a bit to avoid extra locking operation to update the generation
count in in_pcballoc(). (in_pcballoc now returns the pcb locked)
I am planning to convert pcb list handling from a type safe to a reference count
model soon. ( As this allows really freeing the PCBs)
Reviewed by: rwatson@, mohans@
MFC after: 1 week
parameter that can specify configuration parameters:
o rev cloner api's to add optional parameter block
o add SIOCCREATE2 that accepts parameter data
o rev vlan support to use new api (maintain old code)
Reviewed by: arch@
except in places dealing with ifaddr creation or destruction; and
in such special places incomplete ifaddrs should never be linked
to system-wide data structures. Therefore we can eliminate all the
superfluous checks for "ifa->ifa_addr != NULL" and get ready
to the system crashing honestly instead of masking possible bugs.
Suggested by: glebius, jhb, ru
used since FreeBSD-SA-06:04.ipfw.
Adopt send_reject6 to what had been done for legacy IP: no longer
send or permit sending rejects for any but the first fragment.
Discussed with: oleg, csjp (some weeks ago)
o don't assign remote/local host/port information manually between provided
struct in_conninfo and struct syncache, bcopy() it instead
o rename sc_tsrecent to sc_tsreflect in struct syncache to better capture
the purpose of this field
o rename sc_request_r_scale to sc_requested_r_scale for ditto reasons
o fix IPSEC error case printf's to report correct function name
o in syncache_socket() only transpose enhanced tcp options parameters to
struct tcpcb when the inpcb doesn't has TF_NOOPT set
o in syncache_respond() reorder stack variables
o in syncache_respond() remove bogus KASSERT()
No functional changes.
Sponsored by: TCP/IP Optimization Fundraise 2005
o redefine the parameter 'is_syn' to 'flags', add TO_SYN flag and adjust its
usage accordingly
o update the comments to the tcp_dooptions() invocation in
tcp_input():after_listen to reflect reality
o move the logic checking the echoed timestamp out of tcp_dooptions() to the
only place that uses it next to the invocation described in the previous
item
o adjust parsing of TCPOPT_SACK_PERMITTED to use the same style as the others
o add comments in to struct tcpopt.to_flags #defines
No functional changes.
Sponsored by: TCP/IP Optimization Fundraise 2005
