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
( 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
into in_pcbdrop(). Expand logic to detach the inpcb from its bound
address/port so that dropping a TCP connection releases the inpcb resource
reservation, which since the introduction of socket/pcb reference count
updates, has been persisting until the socket closed rather than being
released implicitly due to prior freeing of the inpcb on TCP drop.
MFC after: 3 months
holding the inpcb lock is sufficient to prevent races in reading
the address and port, as both the inpcb lock and pcbinfo lock are
required to change the address/port.
Improve consistency of spelling in assertions about inp != NULL.
MFC after: 3 months
NULL. We currently do allow this to happen, but may want to remove that
possibility in the future. This case can occur when a socket is left
open after TCP wraps up, and the timewait state is recycled. This will
be cleaned up in the future.
Found by: Kazuaki Oda <kaakun at highway dot ne dot jp>
MFC after: 3 months
casts.
Consistently use intotw() to cast inp_ppcb pointers to struct tcptw *
pointers.
Consistently use intotcpcb() to cast inp_ppcb pointers to struct tcpcb *
pointers.
Don't assign tp to the results to intotcpcb() during variable declation
at the top of functions, as that is before the asserts relating to
locking have been performed. Do this later in the function after
appropriate assertions have run to allow that operation to be conisdered
safe.
MFC after: 3 months
- in_pcbdetach(), which removes the link between an inpcb and its
socket.
- in_pcbfree(), which frees a detached pcb.
Unlike the previous in_pcbdetach(), neither of these functions will
attempt to conditionally free the socket, as they are responsible only
for managing in_pcb memory. Mirror these changes into in6_pcbdetach()
by breaking it into in6_pcbdetach() and in6_pcbfree().
While here, eliminate undesired checks for NULL inpcb pointers in
sockets, as we will now have as an invariant that sockets will always
have valid so_pcb pointers.
MFC after: 3 months
we have another PCB which is bound to 0.0.0.0. If a PCB has the
INP_IPV6 flag, then we set its cost higher than IPv4 only PCBs.
Submitted by: Keiichi SHIMA <keiichi__at__iijlab.net>
Obtained from: KAME
MFC after: 1 week
ip.portrange.last and there is the only port for that because:
a) it is not wise; b) it leads to a panic in the random ip port
allocation code. In general we need to disable ip port allocation
randomization if the last - first delta is ridiculous small.
PR: kern/79342
Spotted by: Anjali Kulkarni
Glanced at by: silby
MFC after: 2 weeks
loopback interface. Nobody have explained me sense of this check.
It breaks connect() system call to a destination address which is
loopback routed (e.g. blackholed).
Reviewed by: silence on net@
MFC after: 2 weeks
connection rates, which is causing problems for some users.
To retain the security advantage of random ports and ensure
correct operation for high connection rate users, disable
port randomization during periods of high connection rates.
Whenever the connection rate exceeds randomcps (10 by default),
randomization will be disabled for randomtime (45 by default)
seconds. These thresholds may be tuned via sysctl.
Many thanks to Igor Sysoev, who proved the necessity of this
change and tested many preliminary versions of the patch.
MFC After: 20 seconds
(sorele()/sotryfree()):
- This permits the caller to acquire the accept mutex before the socket
mutex, avoiding sofree() having to drop the socket mutex and re-order,
which could lead to races permitting more than one thread to enter
sofree() after a socket is ready to be free'd.
- This also covers clearing of the so_pcb weak socket reference from
the protocol to the socket, preventing races in clearing and
evaluation of the reference such that sofree() might be called more
than once on the same socket.
This appears to close a race I was able to easily trigger by repeatedly
opening and resetting TCP connections to a host, in which the
tcp_close() code called as a result of the RST raced with the close()
of the accepted socket in the user process resulting in simultaneous
attempts to de-allocate the same socket. The new locking increases
the overhead for operations that may potentially free the socket, so we
will want to revise the synchronization strategy here as we normalize
the reference counting model for sockets. The use of the accept mutex
in freeing of sockets that are not listen sockets is primarily
motivated by the potential need to remove the socket from the
incomplete connection queue on its parent (listen) socket, so cleaning
up the reference model here may allow us to substantially weaken the
synchronization requirements.
RELENG_5_3 candidate.
MFC after: 3 days
Reviewed by: dwhite
Discussed with: gnn, dwhite, green
Reported by: Marc UBM Bocklet <ubm at u-boot-man dot de>
Reported by: Vlad <marchenko at gmail dot com>
Alice is too lazy to write a server application in PF-independent
manner. Therefore she knocks up the server using PF_INET6 only
and allows the IPv6 socket to accept mapped IPv4 as well. An evil
hacker known on IRC as cheshire_cat has an account in the same
system. He starts a process listening on the same port as used
by Alice's server, but in PF_INET. As a consequence, cheshire_cat
will distract all IPv4 traffic supposed to go to Alice's server.
Such sort of port theft was initially enabled by copying the code that
implemented the RFC 2553 semantics on IPv4/6 sockets (see inet6(4)) for
the implied case of the same owner for both connections. After this
change, the above scenario will be impossible. In the same setting,
the user who attempts to start his server last will get EADDRINUSE.
Of course, using IPv4 mapped to IPv6 leads to security complications
in the first place, but there is no reason to make it even more unsafe.
This change doesn't apply to KAME since it affects a FreeBSD-specific
part of the code. It doesn't modify the out-of-box behaviour of the
TCP/IP stack either as long as mapping IPv4 to IPv6 is off by default.
MFC after: 1 month
somewhat clearer, but more importantly allows for a consistent naming
scheme for suser_cred flags.
The old name is still defined, but will be removed in a few days (unless I
hear any complaints...)
Discussed with: rwatson, scottl
Requested by: jhb
do not pick up the first local ip address for the source
ip address, return ENETUNREACH instead.
Submitted by: Gleb Smirnoff
Reviewed by: -current (silence)
SOCK_LOCK(so):
- Hold socket lock over calls to MAC entry points reading or
manipulating socket labels.
- Assert socket lock in MAC entry point implementations.
- When externalizing the socket label, first make a thread-local
copy while holding the socket lock, then release the socket lock
to externalize to userspace.
reference count:
- Assert SOCK_LOCK(so) macros that directly manipulate so_count:
soref(), sorele().
- Assert SOCK_LOCK(so) in macros/functions that rely on the state of
so_count: sofree(), sotryfree().
- Acquire SOCK_LOCK(so) before calling these functions or macros in
various contexts in the stack, both at the socket and protocol
layers.
- In some cases, perform soisdisconnected() before sotryfree(), as
this could result in frobbing of a non-present socket if
sotryfree() actually frees the socket.
- Note that sofree()/sotryfree() will release the socket lock even if
they don't free the socket.
Submitted by: sam
Sponsored by: FreeBSD Foundation
Obtained from: BSD/OS
unless it's in the closed or listening state (remote address
== INADDR_ANY).
If a TCP inpcb is in any other state, it's impossible to steal
its local port or use it for port theft. And if there are
both closed/listening and connected TCP inpcbs on the same
localIP:port couple, the call to in_pcblookup_local() will
find the former due to the design of that function.
No objections raised in: -net, -arch
MFC after: 1 month
implementation taken directly from OpenBSD.
I've resisted committing this for quite some time because of concern over
TIME_WAIT recycling breakage (sequential allocation ensures that there is a
long time before ports are recycled), but recent testing has shown me that
my fears were unwarranted.
to implement this mistake.
Fixed some nearby style bugs (initialization in declaration, misformatting
of this initialization, missing blank line after the declaration, and
comparision of the non-boolean result of the initialization with 0 using
"!". In KNF, "!" is not even used to compare booleans with 0).
zeroed. Doing a bzero on the entire struct route is not more
expensive than assigning NULL to ro.ro_rt and bzero of ro.ro_dst.
Reviewed by: sam (mentor)
Approved by: re (scottl)
rtalloc_ign() in in_pcbconnect_setup() before it is filled out.
Otherwise, stack junk would be left in sin_zero, which could
cause host routes to be ignored because they failed the comparison
in rn_match().
This should fix the wrong source address selection for connect() to
127.0.0.1, among other things.
Reviewed by: sam
Approved by: re (rwatson)
the routing table. Move all usage and references in the tcp stack
from the routing table metrics to the tcp hostcache.
It caches measured parameters of past tcp sessions to provide better
initial start values for following connections from or to the same
source or destination. Depending on the network parameters to/from
the remote host this can lead to significant speedups for new tcp
connections after the first one because they inherit and shortcut
the learning curve.
tcp_hostcache is designed for multiple concurrent access in SMP
environments with high contention and is hash indexed by remote
ip address.
It removes significant locking requirements from the tcp stack with
regard to the routing table.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
