Commit Graph

62 Commits

Author SHA1 Message Date
Marko Zec
d57425ab65 When registering a protocol to an existing protocol domain via
pf_proto_register(), iterate over all existing vnets to call protosw_init()
and thus the appropriate .pr_init() handler in the context of each vnet.
NB in the future we probably want to separate pr_init() handlers into
two, i.e. per-vnet and global, functions.

This change has no impact on nooptions VIMAGE builds.

Approved by:	re (rwatson), julian (mentor)
MFC after:	3 days
2009-08-24 10:03:41 +00:00
Robert Watson
530c006014 Merge the remainder of kern_vimage.c and vimage.h into vnet.c and
vnet.h, we now use jails (rather than vimages) as the abstraction
for virtualization management, and what remained was specific to
virtual network stacks.  Minor cleanups are done in the process,
and comments updated to reflect these changes.

Reviewed by:	bz
Approved by:	re (vimage blanket)
2009-08-01 19:26:27 +00:00
Robert Watson
d0728d7174 Introduce and use a sysinit-based initialization scheme for virtual
network stacks, VNET_SYSINIT:

- Add VNET_SYSINIT and VNET_SYSUNINIT macros to declare events that will
  occur each time a network stack is instantiated and destroyed.  In the
  !VIMAGE case, these are simply mapped into regular SYSINIT/SYSUNINIT.
  For the VIMAGE case, we instead use SYSINIT's to track their order and
  properties on registration, using them for each vnet when created/
  destroyed, or immediately on module load for already-started vnets.
- Remove vnet_modinfo mechanism that existed to serve this purpose
  previously, as well as its dependency scheme: we now just use the
  SYSINIT ordering scheme.
- Implement VNET_DOMAIN_SET() to allow protocol domains to declare that
  they want init functions to be called for each virtual network stack
  rather than just once at boot, compiling down to DOMAIN_SET() in the
  non-VIMAGE case.
- Walk all virtualized kernel subsystems and make use of these instead
  of modinfo or DOMAIN_SET() for init/uninit events.  In some cases,
  convert modular components from using modevent to using sysinit (where
  appropriate).  In some cases, do minor rejuggling of SYSINIT ordering
  to make room for or better manage events.

Portions submitted by:	jhb (VNET_SYSINIT), bz (cleanup)
Discussed with:		jhb, bz, julian, zec
Reviewed by:		bz
Approved by:		re (VIMAGE blanket)
2009-07-23 20:46:49 +00:00
Robert Watson
eddfbb763d Build on Jeff Roberson's linker-set based dynamic per-CPU allocator
(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)
2009-07-14 22:48:30 +00:00
Marko Zec
bc29160df3 Introduce an infrastructure for dismantling vnet instances.
Vnet modules and protocol domains may now register destructor
functions to clean up and release per-module state.  The destructor
mechanisms can be triggered by invoking "vimage -d", or a future
equivalent command which will be provided via the new jail framework.

While this patch introduces numerous placeholder destructor functions,
many of those are currently incomplete, thus leaking memory or (even
worse) failing to stop all running timers.  Many of such issues are
already known and will be incrementaly fixed over the next weeks in
smaller incremental commits.

Apart from introducing new fields in structs ifnet, domain, protosw
and vnet_net, which requires the kernel and modules to be rebuilt, this
change should have no impact on nooptions VIMAGE builds, since vnet
destructors can only be called in VIMAGE kernels.  Moreover,
destructor functions should be in general compiled in only in
options VIMAGE builds, except for kernel modules which can be safely
kldunloaded at run time.

Bump __FreeBSD_version to 800097.
Reviewed by:	bz, julian
Approved by:	rwatson, kib (re), julian (mentor)
2009-06-08 17:15:40 +00:00
Marko Zec
bfe1aba468 Introduce vnet module registration / initialization framework with
dependency tracking and ordering enforcement.

With this change, per-vnet initialization functions introduced with
r190787 are no longer directly called from traditional initialization
functions (which cc in most cases inlined to pre-r190787 code), but are
instead registered via the vnet framework first, and are invoked only
after all prerequisite modules have been initialized.  In the long run,
this framework should allow us to both initialize and dismantle
multiple vnet instances in a correct order.

The problem this change aims to solve is how to replay the
initialization sequence of various network stack components, which
have been traditionally triggered via different mechanisms (SYSINIT,
protosw).  Note that this initialization sequence was and still can be
subtly different depending on whether certain pieces of code have been
statically compiled into the kernel, loaded as modules by boot
loader, or kldloaded at run time.

The approach is simple - we record the initialization sequence
established by the traditional mechanisms whenever vnet_mod_register()
is called for a particular vnet module.  The vnet_mod_register_multi()
variant allows a single initializer function to be registered multiple
times but with different arguments - currently this is only used in
kern/uipc_domain.c by net_add_domain() with different struct domain *
as arguments, which allows for protosw-registered initialization
routines to be invoked in a correct order by the new vnet
initialization framework.

For the purpose of identifying vnet modules, each vnet module has to
have a unique ID, which is statically assigned in sys/vimage.h.
Dynamic assignment of vnet module IDs is not supported yet.

A vnet module may specify a single prerequisite module at registration
time by filling in the vmi_dependson field of its vnet_modinfo struct
with the ID of the module it depends on.  Unless specified otherwise,
all vnet modules depend on VNET_MOD_NET (container for ifnet list head,
rt_tables etc.), which thus has to and will always be initialized
first.  The framework will panic if it detects any unresolved
dependencies before completing system initialization.  Detection of
unresolved dependencies for vnet modules registered after boot
(kldloaded modules) is not provided.

Note that the fact that each module can specify only a single
prerequisite may become problematic in the long run.  In particular,
INET6 depends on INET being already instantiated, due to TCP / UDP
structures residing in INET container.  IPSEC also depends on INET,
which will in turn additionally complicate making INET6-only kernel
configs a reality.

The entire registration framework can be compiled out by turning on the
VIMAGE_GLOBALS kernel config option.

Reviewed by:	bz
Approved by:	julian (mentor)
2009-04-11 05:58:58 +00:00
Ed Schouten
fdef61da21 Remove Giant locking from domains list.
During boot, the domain list is locked with Giant. It is not possible to
register any protocols after the system has booted, so the lock is only
used to protect insertion of entries.

There is already a mutex in uipc_domain.c called dom_mtx. Use this mutex
to lock the list, instead of using Giant. It won't matter anything with
respect to performance, but we'll never get rid of Giant if we don't
remove from places where we don't need it.

Approved by:	rwatson
MFC after:	3 weeks
2009-01-04 19:22:53 +00:00
Robert Watson
192a6120fc Remove two further uses (debugging and NULLing) of pr_ousrreq, missed due
to svn commit in the wrong directory.

Spotted by:	bz
2009-01-04 19:16:36 +00:00
Robert Watson
9c232f86ca Following the recent security advisory, add a comment describing our
invariants and approach for protocol switch methods in protsw_init(),
and also some KASSERT's for non-domain init entries in protocol
switch tables: pru_abort and pru_send must both be implemented.

For now, leave those assertions #if 0'd, since there are a few
protocols that violate them in non-harmful ways.  Whether or not we
should enforce pru_abort being implemented for non-stream protocols
is an interesting question: currently abort is only invoked on stream
sockets in situations where un-accepted sockets must be abruptly
closed (i.e., close() on a listen socket with pending connections),
but in principle it is useful for datagram sockets and most datagram
socket types implement it.

MFC after:	3 weeks
2008-12-25 11:32:38 +00:00
Colin Percival
f0b40b1c97 Prevent cross-site forgery attacks on ftpd(8) due to splitting
long commands into multiple requests. [08:12]

Avoid calling uninitialized function pointers in protocol switch
code. [08:13]

Merry Christmas everybody...

Approved by:	so (cperciva)
Approved by:	re (kensmith)
Security:	FreeBSD-SA-08:12.ftpd, FreeBSD-SA-08:13.protosw
2008-12-23 01:23:09 +00:00
Robert Watson
237fdd787b In keeping with style(9)'s recommendations on macros, use a ';'
after each SYSINIT() macro invocation.  This makes a number of
lightweight C parsers much happier with the FreeBSD kernel
source, including cflow's prcc and lxr.

MFC after:	1 month
Discussed with:	imp, rink
2008-03-16 10:58:09 +00:00
Robert Watson
0bf686c125 Remove the now-unused NET_{LOCK,UNLOCK,ASSERT}_GIANT() macros, which
previously conditionally acquired Giant based on debug.mpsafenet.  As that
has now been removed, they are no longer required.  Removing them
significantly simplifies error-handling in the socket layer, eliminated
quite a bit of unwinding of locking in error cases.

While here clean up the now unneeded opt_net.h, which previously was used
for the NET_WITH_GIANT kernel option.  Clean up some related gotos for
consistency.

Reviewed by:	bz, csjp
Tested by:	kris
Approved by:	re (kensmith)
2007-08-06 14:26:03 +00:00
Robert Watson
33d2bb9ca3 First in a series of changes to remove the now-unused Giant compatibility
framework for non-MPSAFE network protocols:

- Remove debug_mpsafenet variable, sysctl, and tunable.
- Remove NET_NEEDS_GIANT() and associate SYSINITSs used by it to force
  debug.mpsafenet=0 if non-MPSAFE protocols are compiled into the kernel.
- Remove logic to automatically flag interrupt handlers as non-MPSAFE if
  debug.mpsafenet is set for an INTR_TYPE_NET handler.
- Remove logic to automatically flag netisr handlers as non-MPSAFE if
  debug.mpsafenet is set.
- Remove references in a few subsystems, including NFS and Cronyx drivers,
  which keyed off debug_mpsafenet to determine various aspects of their own
  locking behavior.
- Convert NET_LOCK_GIANT(), NET_UNLOCK_GIANT(), and NET_ASSERT_GIANT into
  no-op's, as their entire behavior was determined by the value in
  debug_mpsafenet.
- Alias NET_CALLOUT_MPSAFE to CALLOUT_MPSAFE.

Many remaining references to NET_.*_GIANT() and NET_CALLOUT_MPSAFE are still
present in subsystems, and will be removed in followup commits.

Reviewed by:	bz, jhb
Approved by:	re (kensmith)
2007-07-27 11:59:57 +00:00
Robert Watson
d19e16a72c Generally migrate to ANSI function headers, and remove 'register' use. 2007-05-16 20:41:08 +00:00
Robert Watson
b0668f7151 soreceive_generic(), and sopoll_generic(). Add new functions sosend(),
soreceive(), and sopoll(), which are wrappers for pru_sosend,
pru_soreceive, and pru_sopoll, and are now used univerally by socket
consumers rather than either directly invoking the old so*() functions
or directly invoking the protocol switch method (about an even split
prior to this commit).

This completes an architectural change that was begun in 1996 to permit
protocols to provide substitute implementations, as now used by UDP.
Consumers now uniformly invoke sosend(), soreceive(), and sopoll() to
perform these operations on sockets -- in particular, distributed file
systems and socket system calls.

Architectural head nod:	sam, gnn, wollman
2006-07-24 15:20:08 +00:00
Robert Watson
5908c617bb Several protocol switch functions (pru_abort, pru_detach, pru_sosetlabel)
return void, so don't implement no-op versions of these functions.
Instead, consistently check if those switch pointers are NULL before
invoking them.
2006-07-11 23:18:28 +00:00
Paul Saab
4f590175b7 Allow for nmbclusters and maxsockets to be increased via sysctl.
An eventhandler is used to update all the various zones that depend
on these values.
2006-04-21 09:25:40 +00:00
Andre Oppermann
80444f8803 The sysctls kern.ipc.[max_linkhdr|max_protohdr|max_hdr|max_datalen]
can't be changed from userland.  Make them read-only and provide
descriptions.

kern.ipc.max_datalen must never be less than one byte.  Enforce this
with a panic in net_init_domain().

Sponsored by:	TCP/IP Optimization Fundraise 2005
MFC after:	3 days
2006-02-18 17:16:18 +00:00
Warner Losh
9454b2d864 /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 23:35:40 +00:00
Max Laier
f8aabcb680 Start the protocol timeouts only after all domains have been initialized
completely. For some reason (that I am still curious about) we started to no
longer manage to finish the initialization before the timeouts run the first
time leading to panics when using uninitialized mutex etc.

The root of this problem is that we currently first link a domain to the
domains list and only later initialize the domain's protocols. This should
be reworked in the future, but with the current API it is not possible in
all situations. We settle with this lazy fix for now.

Tested by:	gnn, ru, myself
2004-12-09 11:47:30 +00:00
Max Laier
83727f0c3a Am I smoking crack? Correct stupid, wrong ASSERT -> if conversion and make
it do what I had in mind.

Noticed by:	glebius
Pointyhat to:	me, myself and mlaier
2004-12-02 15:47:15 +00:00
Max Laier
69fb23b73d Implement the check I was talking about in the previous message already.
Introduce domain_init_status to keep track of the init status of the domains
list (surprise). 0 = uninitialized, 1 = initialized/unpopulated, 2 =
initialized/done. Higher values can be used to support late addition of
domains which right now "works", but is potential dangerous. I choose to
only give a warning when doing so.

Use domain_init_status with if_attachdomain[1]() to ensure that we have a
complete domains list when we init the if_afdata array. Store the current
value of domain_init_status in if_afdata_initialized. This way we can update
if_afdata after a new protocol has been added (once that is allowed).

Submitted by:	se (with changes)
Reviewed by:	julian, glebius, se
PR:		kern/73321	(partly)
2004-11-30 22:38:37 +00:00
Gleb Smirnoff
350bc1206a - Introduce protosw_init().
- Utilize it in net_init_domain().
- Utilize it pf_proto_register(), fixing panic on
  natd start.

Reviewed by:	ru, phk, obrien
2004-11-11 19:19:54 +00:00
Poul-Henning Kamp
756d52a195 Initialize struct pr_userreqs in new/sparse style and fill in common
default elements in net_init_domain().

This makes it possible to grep these structures and see any bogosities.
2004-11-08 14:44:54 +00:00
Andre Oppermann
480fa3f985 Aquire GIANT in pf_proto_[un]register() before manipulating the protosw. 2004-10-23 18:52:06 +00:00
Andre Oppermann
312c75c362 Support for dynamically loadable and unloadable protocols within existing protocol
families.

The protosw[] array of any particular protocol family ("domain") is of fixed size
defined at compile time.  This made it impossible to dynamically add or remove any
protocols to or from it.  We work around this by introducing so called SPACER's
which are embedded into the protosw[] array at compile time.  The SPACER's have
a special protocol number (32767) to indicate the fact that they are SPACER's but
are otherwise NULL.  Only as many protocols can be dynamically loaded as SPACER's
are provided in the protosw[] structure.

The pr_usrreqs structure is treated more special and contains pointers to dummy
functions only returning EOPNOTSUPP.  This is needed because the use of those
functions pointers is usually not checked within the kernel because until now it
was assumed to be a valid function pointer.  Instead of fixing all potential
callers we just return a proper error code.

Two new functions provide a clean API to register and unregister a protocol.  The
register function expects a pointer to a valid and complete struct protosw including
a pointer to struct pru_usrreqs provided by the caller.  Upon successful registration
the pr_init() function will be called to finish initialization of the protocol.  The
unregister function restores the SPACER in place of the protocol again.  It is the
responseability of the caller to ensure proper closing of all sockets and freeing
of memory allocation by the unloading protocol.

 sys/protosw.h

  o Define generic PROTO_SPACER to be 32767
  o Prototypes for all pru_*_notsupp() functions
  o Prototypes for pf_proto_[un]register() functions

 kern/uipc_domain.c

  o Global struct pr_usrreqs nousrreqs containing valid pointers to the
    pru_*_notsupp() functions
  o New functions pf_proto_[un]register()

 kern/uipc_socket2.c

  o New functions bodies for all pru_*_notsupp() functions
2004-10-19 15:13:30 +00:00
Warner Losh
7f8a436ff2 Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core
2004-04-05 21:03:37 +00:00
Robert Watson
5a35e5f9af If debug.mpsafenet, initialize UNIX domain socket timeouts as MPSAFE;
otherwise, assert Giant in the callouts.
2004-03-29 17:00:05 +00:00
Sam Leffler
28ace1bf60 move domain list mutex initialization to earlier in the boot sequence so
statically configured modules like netgraph can call net_init_domain

Noticed by:	D.Rock@t-online.de (D. Rock)
2003-09-02 20:59:23 +00:00
Sam Leffler
b9651df42c o interlock domain list when adding domains
o remove irrlevant spl

Notes:

1. We don't lock domain list traversals as this is safe until we start
   removing domains.
2. The calculation of max_datalen in net_init_domain appears safe as
   noone depends on max_hdr and max_datalen having consistent values.
3. Giant is still held for fast and slow timeouts; this must stay until
   each timeout routine is properly locked (coming soon).

Sponsored by:	FreeBSD Fondation
2003-09-01 05:01:55 +00:00
David E. O'Brien
677b542ea2 Use __FBSDID(). 2003-06-11 00:56:59 +00:00
Rob Braun
d132c84f07 Fix a spelling error.
Submitted by:	jkh
Reviewed by:	zarzycki
2003-03-07 22:47:32 +00:00
Seigo Tanimura
4cc20ab1f0 Back out my lats commit of locking down a socket, it conflicts with hsu's work.
Requested by:	hsu
2002-05-31 11:52:35 +00:00
Seigo Tanimura
243917fe3b Lock down a socket, milestone 1.
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
2002-05-20 05:41:09 +00:00
Jeff Roberson
586c8b6b29 Add calls to uma_zone_set_max() to restore previously enforced limits. 2002-03-20 05:30:58 +00:00
Jeff Roberson
c897b81311 Remove references to vm_zone.h and switch over to the new uma API.
Also, remove maxsockets.  If you look carefully you'll notice that the old
zone allocator never honored this anyway.
2002-03-20 04:09:59 +00:00
Alfred Perlstein
4d77a549fe Remove __P. 2002-03-19 21:25:46 +00:00
Chad David
995a2227c5 Update the comment about System initialization to reflect the use of
DOMAIN_SET(9) instead of SYSINIT for adding domains at startup.

Reviewed by: alfred
2001-12-08 04:20:54 +00:00
Hajimu UMEMOTO
3384154590 Sync with recent KAME.
This work was based on kame-20010528-freebsd43-snap.tgz and some
critical problem after the snap was out were fixed.
There are many many changes since last KAME merge.

TODO:
  - The definitions of SADB_* in sys/net/pfkeyv2.h are still different
    from RFC2407/IANA assignment because of binary compatibility
    issue.  It should be fixed under 5-CURRENT.
  - ip6po_m member of struct ip6_pktopts is no longer used.  But, it
    is still there because of binary compatibility issue.  It should
    be removed under 5-CURRENT.

Reviewed by:	itojun
Obtained from:	KAME
MFC after:	3 weeks
2001-06-11 12:39:29 +00:00
Jake Burkholder
4f55983606 Use callout_reset instead of timeout(9). Most callouts are statically
allocated, 2 have been added to struct proc for setitimer and sleep.

Reviewed by:	jhb, jlemon
2000-11-27 22:52:31 +00:00
Peter Wemm
c3aac50f28 $Id$ -> $FreeBSD$ 1999-08-28 01:08:13 +00:00
Peter Wemm
5b23857d22 Redo domain registration to use SYSINITS rather than linker sets.
Get rid of the spl wrapper kludge, it doesn't seem to be needed between
init calls since all that's running is the domain/protocol timers and they
are safe since domain list modifications are splnet() protected (which
blocks the timers)
1999-04-26 08:56:09 +00:00
Julian Elischer
ea5f0893fd Minor rearranging of code to allow simple protocol domains to be
added as KLDs.
1999-01-21 00:26:41 +00:00
Garrett Wollman
98271db4d5 Convert socket structures to be type-stable and add a version number.
Define a parameter which indicates the maximum number of sockets in a
system, and use this to size the zone allocators used for sockets and
for certain PCBs.

Convert PF_LOCAL PCB structures to be type-stable and add a version number.

Define an external format for infomation about socket structures and use
it in several places.

Define a mechanism to get all PF_LOCAL and PF_INET PCB lists through
sysctl(3) without blocking network interrupts for an unreasonable
length of time.  This probably still has some bugs and/or race
conditions, but it seems to work well enough on my machines.

It is now possible for `netstat' to get almost all of its information
via the sysctl(3) interface rather than reading kmem (changes to follow).
1998-05-15 20:11:40 +00:00
Bruce Evans
514ede0953 Fixed gratuitous ANSIisms. 1997-09-16 11:44:05 +00:00
Garrett Wollman
a29f300e80 The long-awaited mega-massive-network-code- cleanup. Part I.
This commit includes the following changes:
1) Old-style (pr_usrreq()) protocols are no longer supported, the compatibility
glue for them is deleted, and the kernel will panic on boot if any are compiled
in.

2) Certain protocol entry points are modified to take a process structure,
so they they can easily tell whether or not it is possible to sleep, and
also to access credentials.

3) SS_PRIV is no more, and with it goes the SO_PRIVSTATE setsockopt()
call.  Protocols should use the process pointer they are now passed.

4) The PF_LOCAL and PF_ROUTE families have been updated to use the new
style, as has the `raw' skeleton family.

5) PF_LOCAL sockets now obey the process's umask when creating a socket
in the filesystem.

As a result, LINT is now broken.  I'm hoping that some enterprising hacker
with a bit more time will either make the broken bits work (should be
easy for netipx) or dike them out.
1997-04-27 20:01:29 +00:00
Peter Wemm
6875d25465 Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.
1997-02-22 09:48:43 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
Garrett Wollman
2c37256e5a Modify the kernel to use the new pr_usrreqs interface rather than the old
pr_usrreq mechanism which was poorly designed and error-prone.  This
commit renames pr_usrreq to pr_ousrreq so that old code which depended on it
would break in an obvious manner.  This commit also implements the new
interface for TCP, although the old function is left as an example
(#ifdef'ed out).  This commit ALSO fixes a longstanding bug in the
TCP timer processing (introduced by davidg on 1995/04/12) which caused
timer processing on a TCB to always stop after a single timer had
expired (because it misinterpreted the return value from tcp_usrreq()
to indicate that the TCB had been deleted).  Finally, some code
related to polling has been deleted from if.c because it is not
relevant t -current and doesn't look at all like my current code.
1996-07-11 16:32:50 +00:00
Garrett Wollman
1e4ad9ce28 This is a proposal-in-code for a substantial modification of the way
the high kernel calls into a protocol stack to perform requests on the
user's behalf.  We replace the pr_usrreq() entry in struct protosw with a
pointer to a structure containing pointers to functions which implement
the various reuqests; each function is declared with the correct type and
number of arguments.  (This is unlike the current scheme in which a quarter
of the requests take arguments of type other than (struct mbuf *) and the
difference is papered over with casts.)  There are a few benefits to this
new scheme:

1) Arguments are passed with their correct types, and null-pointer dummies
   are no longer necessary.

2) There should be slightly better caching effects from eliminating
   the prximity to extraneous code and th switch in pr_usrreq().

3) It becomes much easier to change the types of the arguments to something
   other than `struct mbuf *' (e.g.,pushing the work of sosend() into
   the protocol as advocated by Van Jacobson).

There is one principal drawback: existing protocol stacks need to
be modified.  This is alleviated by compatibility code in
uipc_socket2.c and uipc_domain.c which emulates the new interface
in terms of the old and vice versa.

This idea is not original to me.  I  read about what Jacobson did
in one of his papers and have tried to implement  the first steps
towards something like that here.  Much work remains to be done.
1996-07-09 19:12:53 +00:00