mbuf that was fully consumed by the previous call, the mbuf ptr returned by the
current call ends up being the previous mbuf in the sb chain to the one that
contains the data we want.
This does not cause any observable issues because the mbuf copy routines happily
walk the mbuf chain to get to the data at the moff offset, which in this case
means they effectively skip over the mbuf returned by sbsndptr().
We can't adjust sb->sb_sndptr during the previous call for this case because the
next mbuf in the chain may not exist yet. We therefore need to detect the
condition and make the adjustment during the current call.
Fix by detecting the special case of moff being at the start of the next mbuf in
the chain and adjust the required accounting variables accordingly.
Reviewed by: andre
MFC after: 2 weeks
and the maximum TCP send and receive buffer limits from 256kB
to 2MB.
For sb_max_adj we need to add the cast as already used in the sysctl
handler to not overflow the type doing the maths.
Note that this is just the defaults. They will allow more memory
to be consumed per socket/connection if needed but not change the
default "idle" memory consumption. All values are still tunable
by sysctls.
Suggested by: gnn
Discussed on: arch (Mar and Aug 2011)
MFC after: 3 weeks
Approved by: re (kib)
chains) to pure data mbufs using m_demote(). This removes the
packet header and all m_tag information as they are not meaningful
anymore on a stream socket where mbufs are linked through m->m_next.
Strictly speaking a packet header can be only ever valid on the first
mbuf in an m_next chain.
sbcompress() was doing this already when the mbuf chain layout lent
itself to it (e.g. header splitting or merge-append), just not
consistently.
This frees resources at socket buffer append time instead of at
sbdrop_internal() time after data has been read from the socket.
For MAC the per packet information has done its duty and during
socket buffer appending the policy of the socket itself takes over.
With the append the packet boundaries disappear naturally and with
it any context that was based on it. None of the residual information
from mbuf headers in the socket buffer on stream sockets was looked at.
- Each socket upcall is now invoked with the appropriate socket buffer
locked. It is not permissible to call soisconnected() with this lock
held; however, so socket upcalls now return an integer value. The two
possible values are SU_OK and SU_ISCONNECTED. If an upcall returns
SU_ISCONNECTED, then the soisconnected() will be invoked on the
socket after the socket buffer lock is dropped.
- A new API is provided for setting and clearing socket upcalls. The
API consists of soupcall_set() and soupcall_clear().
- To simplify locking, each socket buffer now has a separate upcall.
- When a socket upcall returns SU_ISCONNECTED, the upcall is cleared from
the receive socket buffer automatically. Note that a SO_SND upcall
should never return SU_ISCONNECTED.
- All this means that accept filters should now return SU_ISCONNECTED
instead of calling soisconnected() directly. They also no longer need
to explicitly clear the upcall on the new socket.
- The HTTP accept filter still uses soupcall_set() to manage its internal
state machine, but other accept filters no longer have any explicit
knowlege of socket upcall internals aside from their return value.
- The various RPC client upcalls currently drop the socket buffer lock
while invoking soreceive() as a temporary band-aid. The plan for
the future is to add a new flag to allow soreceive() to be called with
the socket buffer locked.
- The AIO callback for socket I/O is now also invoked with the socket
buffer locked. Previously sowakeup() would drop the socket buffer
lock only to call aio_swake() which immediately re-acquired the socket
buffer lock for the duration of the function call.
Discussed with: rwatson, rmacklem
The main problem is that sbappendrecord_locked() relies on sbcompress()
to set sb_mbtail. This will not happen if sbappendrecord_locked() is
called with mbuf chain made of exactly one mbuf (i.e. m0->m_next == NULL).
In this case sbcompress() will be called with m == NULL and will do
nothing. I'm not entirely sure if m == NULL is a valid argument for
sbcompress(), and, it rather pointless to call it like that, but keep
calling it so it can do SBLASTMBUFCHK().
The problem is triggered by the SOCKBUF_DEBUG kernel option that
enables SBLASTRECORDCHK() and SBLASTMBUFCHK() checks.
PR: kern/126742
Investigated by: pluknet < pluknet -at- gmail -dot- com >
No response from: freebsd-current@, freebsd-bluetooth@
MFC after: 3 days
somehow.
As a consequence we may now get an unexpected result(*).
Catch that error cases with a well defined panic giving appropriate
pointers to ease debugging.
(*) While the concensus was that the case should never happen unless
there was a bug, noone was definitively sure.
Discussed with: kmacy (about 8 months back)
Reviewed by: silby (as part of a larger patch in March)
MFC after: 2 months
(all types) used per socket buffer.
Add support to netstat to print out all of the socket buffer
statistics.
Update the netstat manual page to describe the new -x flag
which gives the extended output.
Reviewed by: rwatson, julian
- Expose sbrelease_internal(), a variant of sbrelease() with no
expectations about the validity of locks in the socket buffer.
- Use sbrelease_internel() in sorflush(), and as a result avoid intializing
and destroying a socket buffer lock for the temporary stack copy of the
actual buffer, asb.
- Add a comment indicating why we do what we do, and remove an XXX since
things have gotten less ugly in sorflush() lately.
This makes socket close cleaner, and possibly also marginally faster.
MFC after: 3 weeks
read socket buffers in shutdown() and close():
- Call socantrcvmore() before sblock() to dislodge any threads that
might be sleeping (potentially indefinitely) while holding sblock(),
such as a thread blocked in recv().
- Flag the sblock() call as non-interruptible so that a signal
delivered to the thread calling sorflush() doesn't cause sblock() to
fail. The sblock() is required to ensure that all other socket
consumer threads have, in fact, left, and do not enter, the socket
buffer until we're done flushin it.
To implement the latter, change the 'flags' argument to sblock() to
accept two flags, SBL_WAIT and SBL_NOINTR, rather than one M_WAITOK
flag. When SBL_NOINTR is set, it forces a non-interruptible sx
acquisition, regardless of the setting of the disposition of SB_NOINTR
on the socket buffer; without this change it would be possible for
another thread to clear SB_NOINTR between when the socket buffer mutex
is released and sblock() is invoked.
Reviewed by: bz, kmacy
Reported by: Jos Backus <jos at catnook dot com>
details from consumers.
- Track individual selecters on a per-descriptor basis such that there
are no longer collisions and after sleeping for events only those
descriptors which triggered events must be rescaned.
- Protect the selinfo (per descriptor) structure with a mtx pool mutex.
mtx pool mutexes were chosen to preserve api compatibility with
existing code which does nothing but bzero() to setup selinfo
structures.
- Use a per-thread wait channel rather than a global wait channel.
- Hide select implementation details in a seltd structure which is
opaque to the rest of the kernel.
- Provide a 'selsocket' interface for those kernel consumers who wish to
select on a socket when they have no fd so they no longer have to
be aware of select implementation details.
Tested by: kris
Reviewed on: arch
properly observe the SB_NOINTR flag in sblock. This restores the
required behavior that lock acquisition be interruptible on the socket
buffer I/O serialization lock to allow threads waiting for I/O to be
signaled even if they aren't the thread currently holding the I/O lock.
With this change, the sblock regression test is again passed.
Reported by: alfred
sx(9) handiwork: attilio
on each socket buffer with the socket buffer's mutex. This sleep lock is
used to serialize I/O on sockets in order to prevent I/O interlacing.
This change replaces the custom sleep lock with an sx(9) lock, which
results in marginally better performance, better handling of contention
during simultaneous socket I/O across multiple threads, and a cleaner
separation between the different layers of locking in socket buffers.
Specifically, the socket buffer mutex is now solely responsible for
serializing simultaneous operation on the socket buffer data structure,
and not for I/O serialization.
While here, fix two historic bugs:
(1) a bug allowing I/O to be occasionally interlaced during long I/O
operations (discovere by Isilon).
(2) a bug in which failed non-blocking acquisition of the socket buffer
I/O serialization lock might be ignored (discovered by sam).
SCTP portion of this patch submitted by rrs.
other C files:
- Move sbcreatecontrol() and sbtoxsockbuf() to uipc_sockbuf.c. While
sbcreatecontrol() is really an mbuf allocation routine, it does its work
with awareness of the layout of socket buffer memory.
- Move pru_*() protocol switch stubs to uipc_socket.c where the non-stub
versions of several of these functions live. Likewise, move socket state
transition calls (soisconnecting(), etc) to uipc_socket.c. Moveo
sodupsockaddr() and sotoxsocket().
longer referenced by other threads (hence our freeing it), we don't need
to set the can't send and can't receive flags, wake up the consumers,
perform two levels of locking, etc. Implement a fast-path teardown,
sbdestroy(), which flushes and releases each socket buffer. A manual
dom_dispose of the receive buffer is still required explicitly to GC
any in-flight file descriptors, etc, before flushing the buffer.
This results in a 9% UP performance improvement and 16% SMP performance
improvement on a tight loop of socket();close(); in micro-benchmarking,
but will likely also affect CPU-bound macro-benchmark performance.
specific routines from uipc_socket2.c following repo-copy. We might
rethink the location of one or two at some point, but the division was
relatively clean. uipc_sockbuf.c is now the home of routines that
manipulate socket buffers.
basically always violated) invariannts of soreceive(), which assume
that the first mbuf pointer in a receive socket buffer can't change
while the SB_LOCK sleepable lock is held on the socket buffer,
which is precisely what these functions do. No current protocols
invoke these functions, and removing them will help discourage them
from ever being used. I should have removed them years ago, but
lost track of it.
MFC after: 1 week
Prodded almost by accident by: peter
- Move sonewconn(), which creates new sockets for incoming connections on
listen sockets, so that all socket allocate code is together in
uipc_socket.c.
- Move 'maxsockets' and associated sysctls to uipc_socket.c with the
socket allocation code.
- Move kern.ipc sysctl node to uipc_socket.c, add a SYSCTL_DECL() for it
to sysctl.h and remove lots of scattered implementations in various
IPC modules.
- Sort sodealloc() after soalloc() in uipc_socket.c for dependency order
reasons. Statisticize soalloc() and sodealloc() as they are now
required only in uipc_socket.c, and are internal to the socket
implementation.
After this change, socket allocation and deallocation is entirely
centralized in one file, and uipc_socket2.c consists entirely of socket
buffer manipulation and default protocol switch functions.
MFC after: 1 month
rather than an error. Detaches do not "fail", they other occur or
the protocol flags SS_PROTOREF to take ownership of the socket.
soclose() no longer looks at so_pcb to see if it's NULL, relying
entirely on the protocol to decide whether it's time to free the
socket or not using SS_PROTOREF. so_pcb is now entirely owned and
managed by the protocol code. Likewise, no longer test so_pcb in
other socket functions, such as soreceive(), which have no business
digging into protocol internals.
Protocol detach routines no longer try to free the socket on detach,
this is performed in the socket code if the protocol permits it.
In rts_detach(), no longer test for rp != NULL in detach, and
likewise in other protocols that don't permit a NULL so_pcb, reduce
the incidence of testing for it during detach.
netinet and netinet6 are not fully updated to this change, which
will be in an upcoming commit. In their current state they may leak
memory or panic.
MFC after: 3 months
than an int, as an error here is not meaningful. Modify soabort() to
unconditionally free the socket on the return of pru_abort(), and
modify most protocols to no longer conditionally free the socket,
since the caller will do this.
This commit likely leaves parts of netinet and netinet6 in a situation
where they may panic or leak memory, as they have not are not fully
updated by this commit. This will be corrected shortly in followup
commits to these components.
MFC after: 3 months
REGRESSION is enabled, allows user space to dictate that sonewconn()
should skip it's "skip the hard work" check to see if the listen
queue is full, and instead proceed with allocation of a socket and
trimming of the overflowed queue. This makes it easier to test the
queue overflow logic.
MFC after: 1 month
consumers ignore the return value, soabort() is required to succeed,
and protocols produce errors here to report multiple freeing of the
pcb, which we hope to eliminate.
connection queue for a new connection. It was removing connections
from the wrong list.
Submitted by: Paul Mikesell
Sponsored by: Isilon Systems
MFC after: 1 week
Having an additional MT_HEADER mbuf type is superfluous and redundant
as nothing depends on it. It only adds a layer of confusion. The
distinction between header mbuf's and data mbuf's is solely done
through the m->m_flags M_PKTHDR flag.
Non-native code is not changed in this commit. For compatibility
MT_HEADER is mapped to MT_DATA.
Sponsored by: TCP/IP Optimization Fundraise 2005
following the protocol pru_listen() call to solisten_proto(), so
that it occurs under the socket lock acquisition that also sets
SO_ACCEPTCONN. This requires passing the new backlog parameter
to the protocol, which also allows the protocol to be aware of
changes in queue limit should it wish to do something about the
new queue limit. This continues a move towards the socket layer
acting as a library for the protocol.
Bump __FreeBSD_version due to a change in the in-kernel protocol
interface. This change has been tested with IPv4 and UNIX domain
sockets, but not other protocols.
quite a bit of reading to figure it out, and I want to avoid figuring
it out again.
Convert an if (foo) else printf("this is almost a panic") into a
KASSERT.
MFC after: 3 days
- Introducing the possibility of using locks different than mutexes
for the knlist locking. In order to do this, we add three arguments to
knlist_init() to specify the functions to use to lock, unlock and
check if the lock is owned. If these arguments are NULL, we assume
mtx_lock, mtx_unlock and mtx_owned, respectively.
- Using the vnode lock for the knlist locking, when doing kqueue operations
on a vnode. This way, we don't have to lock the vnode while holding a
mutex, in filt_vfsread.
Reviewed by: jmg
Approved by: re (scottl), scottl (mentor override)
Pointyhat to: ssouhlal
Will be happy: everyone
that protects socket and receive socket buffer state, and a second
mutex to protect send socket buffer state. In some places, the
mutex shared between the socket and receive socket buffer will be
acquired twice, once by each layer, resulting in some
inconsistency, but providing the abstraction benefit of being able
to more easily separate the two mutexes in the future if desired.
When transitioning a socket to the SS_ISDISCONNECTING or
SS_ISDISCONNECTED states, grab the socket/receive socket buffer lock
once rather than grabbing it as the socket lock, modifying socket
state, then grabbing a second time as the receive lock in order to
modify the socket buffer state to indicate no further data can be
read. This change is believed to close a race between the change in
socket state and the change in socket buffer state, which for a
remotely initiated close on a UNIX domain socket, resulted in
soreceive() returning ENOTCONN rather than an EOF condition.
A similar race still exists in the case of send, however, and is
harder to fix as the socket and send socket buffer mutexes are not
the same, and we would like to avoid holding combinations of socket
mutexes over sb_upcall until we've finished clarifying the locking
protocol for upcalls.
This change has the side affect of reducing the number of mutex
operations to initiate disconnect or perform disconnect on a
socket by two.
PR: 78824
Rerported by: Marc Olzheim <marcolz@stack.nl>
MFC after: 2 weeks
so that the socket lock is held over the test-and-set removal of the
accept filter option during connect, and the two socket mutex regions
(transition to connected, perform accept filter) are combined.
connection status before inserting the new socket into the listen
socket's accept queue, or there might be a race in which another thread
wakes up when the accept lock is released, and sees the socket before its
state is set correctly. The wakeup still occurs after the accept lock is
released. There have been no diagnoses of this bug in real-world systems
(as yet).
MFC after: 3 days
