a socket from a regular socket to a listening socket able to accept new
connections. As part of this state transition, solisten() calls into the
protocol to update protocol-layer state. There were several bugs in this
implementation that could result in a race wherein a TCP SYN received
in the interval between the protocol state transition and the shortly
following socket layer transition would result in a panic in the TCP code,
as the socket would be in the TCPS_LISTEN state, but the socket would not
have the SO_ACCEPTCONN flag set.
This change does the following:
- Pushes the socket state transition from the socket layer solisten() to
to socket "library" routines called from the protocol. This permits
the socket routines to be called while holding the protocol mutexes,
preventing a race exposing the incomplete socket state transition to TCP
after the TCP state transition has completed. The check for a socket
layer state transition is performed by solisten_proto_check(), and the
actual transition is performed by solisten_proto().
- Holds the socket lock for the duration of the socket state test and set,
and over the protocol layer state transition, which is now possible as
the socket lock is acquired by the protocol layer, rather than vice
versa. This prevents additional state related races in the socket
layer.
This permits the dual transition of socket layer and protocol layer state
to occur while holding locks for both layers, making the two changes
atomic with respect to one another. Similar changes are likely require
elsewhere in the socket/protocol code.
Reported by: Peter Holm <peter@holm.cc>
Review and fixes from: emax, Antoine Brodin <antoine.brodin@laposte.net>
Philosophical head nod: gnn
portion of IPX/SPX:
- Protect IPX PCB lists with the IPX PCB list mutex, in particular
when calling PCB and PCB list manipulation routines in ipx_pcb.c.
- Protect both IPX PCB state and SPX PCB state using the IPX PCB
mutex.
- Generally annotate locking, as well as adding liberal use of lock
assertions to document locking requirements.
- Where possible, use unlocked reads when reading integer or smaller
sized socket options on SPX sockets.
- De-spl throughout.
Notes:
- spx_input() expects both the list mutex and PCB mutex to be held
on entry, but will release both on return. Because sonewconn() is
called from spx_input(), it may actually drop one PCB lock and
acquire another during generation of a new connection, meaning the
caller is not in a position to unlock the PCB mutex.
MFC after: 3 weeks
were derived from more complex TCP versions of the same:
- spx_close(), spx_disconnect(), spx_drop(), and spx_usrclosed() all
always free's the spxpcb invalidating the argument, so a return
value is not required to indicate if it has.
- Annotate that the cb arguments to each of these functions is
invalidated via a comment.
- When tearing down a pcb due to sonewconn() having failed, mark the
cb as NULL; later, when deciding whether to store trace information
due to SO_DEBUG, check that cb is not NULL before dereferencing or
a NULL pointer dereference may occur.
MFC after: 3 weeks
spx_reass() to increase atomicity across multiple operations on the
socket buffer when iterating over the SPX fragment reassembly list
for the ipxpcb, as well a to reduce the number of locking operations.
record loop for ACK'd data, rather than relying on lokcing in
sbdroprecord() and sowwakeup(), reducing the number of lock operations
as well as eliminating a possible race against the head of the send
buffer mbuf chain. Use the _locked variants of sbdroprecord() and
sowwakeup().
properly handle the case where a connection is disconnected. The
queue(9)-enabled version of this code broke from the inner but not
outer loop, and so potentially frobbed an ipxpcb flag after the ipxpcb
was free'd, which might be picked up later by the malloc debugging
code. Properly break from the loop context and avoid touching the
cb/ipxpcb after free.
- ipx_pcbnotify(), which is never called.
- ipx_rtchange(), which is never called, is incomplete inplemented, and
also #ifdef notdef.
- spx_fixmtu(), which is never called, is incompletely implemented, and
also #ifdef notdef.
socket from its accept queue when aborting it during a new inbound
connection. Update spx_input() to acquire the accept lock, assert
the condition of the socket on its parent queue, and approriately
disconnect it from the queue before calling soabort() on it.
flags relating to several aspects of socket functionality. This change
breaks out several bits relating to send and receive operation into a
new per-socket buffer field, sb_state, in order to facilitate locking.
This is required because, in order to provide more granular locking of
sockets, different state fields have different locking properties. The
following fields are moved to sb_state:
SS_CANTRCVMORE (so_state)
SS_CANTSENDMORE (so_state)
SS_RCVATMARK (so_state)
Rename respectively to:
SBS_CANTRCVMORE (so_rcv.sb_state)
SBS_CANTSENDMORE (so_snd.sb_state)
SBS_RCVATMARK (so_rcv.sb_state)
This facilitates locking by isolating fields to be located with other
identically locked fields, and permits greater granularity in socket
locking by avoiding storing fields with different locking semantics in
the same short (avoiding locking conflicts). In the future, we may
wish to coallesce sb_state and sb_flags; for the time being I leave
them separate and there is no additional memory overhead due to the
packing/alignment of shorts in the socket buffer structure.
functions in kern_socket.c.
Rename the "canwait" field to "mflags" and pass M_WAITOK and M_NOWAIT
in from the caller context rather than "1" or "0".
Correct mflags pass into mac_init_socket() from previous commit to not
include M_ZERO.
Submitted by: sam
the MAC label referenced from 'struct socket' in the IPv4 and
IPv6-based protocols. This permits MAC labels to be checked during
network delivery operations without dereferencing inp->inp_socket
to get to so->so_label, which will eventually avoid our having to
grab the socket lock during delivery at the network layer.
This change introduces 'struct inpcb' as a labeled object to the
MAC Framework, along with the normal circus of entry points:
initialization, creation from socket, destruction, as well as a
delivery access control check.
For most policies, the inpcb label will simply be a cache of the
socket label, so a new protocol switch method is introduced,
pr_sosetlabel() to notify protocols that the socket layer label
has been updated so that the cache can be updated while holding
appropriate locks. Most protocols implement this using
pru_sosetlabel_null(), but IPv4/IPv6 protocols using inpcbs use
the the worker function in_pcbsosetlabel(), which calls into the
MAC Framework to perform a cache update.
Biba, LOMAC, and MLS implement these entry points, as do the stub
policy, and test policy.
Reviewed by: sam, bms
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
o Add a mutex (sb_mtx) to struct sockbuf. This protects the data in a
socket buffer. The mutex in the receive buffer also protects the data
in struct socket.
o Determine the lock strategy for each members in struct socket.
o Lock down the following members:
- so_count
- so_options
- so_linger
- so_state
o Remove *_locked() socket APIs. Make the following socket APIs
touching the members above now require a locked socket:
- sodisconnect()
- soisconnected()
- soisconnecting()
- soisdisconnected()
- soisdisconnecting()
- sofree()
- soref()
- sorele()
- sorwakeup()
- sotryfree()
- sowakeup()
- sowwakeup()
Reviewed by: alfred
Requested by: bde
Since locking sigio_lock is usually followed by calling pgsigio(),
move the declaration of sigio_lock and the definitions of SIGIO_*() to
sys/signalvar.h.
While I am here, sort include files alphabetically, where possible.
this is a low-functionality change that changes the kernel to access the main
thread of a process via the linked list of threads rather than
assuming that it is embedded in the process. It IS still embeded there
but remove all teh code that assumes that in preparation for the next commit
which will actually move it out.
Reviewed by: peter@freebsd.org, gallatin@cs.duke.edu, benno rice,
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
other "system" header files.
Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.
Sort sys/*.h includes where possible in affected files.
OK'ed by: bde (with reservations)
This is because calls with M_WAIT (now M_TRYWAIT) may not wait
forever when nothing is available for allocation, and may end up
returning NULL. Hopefully we now communicate more of the right thing
to developers and make it very clear that it's necessary to check whether
calls with M_(TRY)WAIT also resulted in a failed allocation.
M_TRYWAIT basically means "try harder, block if necessary, but don't
necessarily wait forever." The time spent blocking is tunable with
the kern.ipc.mbuf_wait sysctl.
M_WAIT is now deprecated but still defined for the next little while.
* Fix a typo in a comment in mbuf.h
* Fix some code that was actually passing the mbuf subsystem's M_WAIT to
malloc(). Made it pass M_WAITOK instead. If we were ever to redefine the
value of the M_WAIT flag, this could have became a big problem.
another specialized mbuf type in the process. Also clean up some
of the cruft surrounding IPFW, multicast routing, RSVP, and other
ill-explored corners.
socket addresses in mbufs. (Socket buffers are the one exception.) A number
of kernel APIs needed to get fixed in order to make this happen. Also,
fix three protocol families which kept PCBs in mbufs to not malloc them
instead. Delete some old compatibility cruft while we're at it, and add
some new routines in the in_cksum family.
Use the MAC address of an interface for the host part of an IPX address
and not the MAC address of the first interface for every IPX address.
This is more inline with the way others like Novell do it.
Mostly Submitted by: "Serge A. Babkin" <babkin@hq.icb.chel.su>
Take out the error messages (the ip icmp equivalent) with #ifdef IPXERRORMSGS.
This is bogus and as far as I could figure out IPX don't have anything like
it. This is a leftover from its XNS heritage. If nobody complains, I will
take it out completely in a few weeks.
Add some more ipxstat statistics counters.
Make ipxprintfs a sysctl variable and off by default.
Add IPX Netbios "routing" support. This is off by default and can be
switched on with a sysctl knob.
General code cleanup to at least use the same style throughout the IPX
code, but also be more style(9) conformant. Also make a lot of functions
static.
If I don't get any complaints I'll bring all of this over to the 2.2 tree
in a few weeks.
