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freebsd-nq/sys/kern/uipc_domain.c
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

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/*
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)uipc_domain.c 8.2 (Berkeley) 10/18/93
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <vm/uma.h>
/*
* System initialization
*
* Note: domain initialization takes place on a per domain basis
* as a result of traversing a SYSINIT linker set. Most likely,
* each domain would want to call DOMAIN_SET(9) itself, which
* would cause the domain to be added just after domaininit()
* is called during startup.
*
* See DOMAIN_SET(9) for details on its use.
*/
static void domaininit(void *);
SYSINIT(domain, SI_SUB_PROTO_DOMAIN, SI_ORDER_FIRST, domaininit, NULL)
static struct callout pffast_callout;
static struct callout pfslow_callout;
static void pffasttimo(void *);
static void pfslowtimo(void *);
struct domain *domains; /* registered protocol domains */
struct mtx dom_mtx; /* domain list lock */
MTX_SYSINIT(domain, &dom_mtx, "domain list", MTX_DEF);
/*
* Dummy protocol specific user requests function pointer array.
* All functions return EOPNOTSUPP.
*/
struct pr_usrreqs nousrreqs = {
pru_abort_notsupp, pru_accept_notsupp, pru_attach_notsupp,
pru_bind_notsupp, pru_connect_notsupp, pru_connect2_notsupp,
pru_control_notsupp, pru_detach_notsupp, pru_disconnect_notsupp,
pru_listen_notsupp, pru_peeraddr_notsupp, pru_rcvd_notsupp,
pru_rcvoob_notsupp, pru_send_notsupp, pru_sense_null,
pru_shutdown_notsupp, pru_sockaddr_notsupp, pru_sosend_notsupp,
pru_soreceive_notsupp, pru_sopoll_notsupp, pru_sosetlabel_null
};
/*
* Add a new protocol domain to the list of supported domains
* Note: you cant unload it again because a socket may be using it.
* XXX can't fail at this time.
*/
static void
net_init_domain(struct domain *dp)
{
struct protosw *pr;
if (dp->dom_init)
(*dp->dom_init)();
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++){
if (pr->pr_usrreqs == 0)
panic("domaininit: %ssw[%d] has no usrreqs!",
dp->dom_name,
(int)(pr - dp->dom_protosw));
if (pr->pr_init)
(*pr->pr_init)();
}
/*
* update global information about maximums
*/
max_hdr = max_linkhdr + max_protohdr;
max_datalen = MHLEN - max_hdr;
}
/*
* Add a new protocol domain to the list of supported domains
* Note: you cant unload it again because a socket may be using it.
* XXX can't fail at this time.
*/
void
net_add_domain(void *data)
{
struct domain *dp;
dp = (struct domain *)data;
mtx_lock(&dom_mtx);
dp->dom_next = domains;
domains = dp;
mtx_unlock(&dom_mtx);
net_init_domain(dp);
}
/* ARGSUSED*/
static void
domaininit(void *dummy)
{
/*
* Before we do any setup, make sure to initialize the
* zone allocator we get struct sockets from.
*/
socket_zone = uma_zcreate("socket", sizeof(struct socket), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_zone_set_max(socket_zone, maxsockets);
if (max_linkhdr < 16) /* XXX */
max_linkhdr = 16;
if (debug_mpsafenet) {
callout_init(&pffast_callout, CALLOUT_MPSAFE);
callout_init(&pfslow_callout, CALLOUT_MPSAFE);
} else {
callout_init(&pffast_callout, 0);
callout_init(&pfslow_callout, 0);
}
callout_reset(&pffast_callout, 1, pffasttimo, NULL);
callout_reset(&pfslow_callout, 1, pfslowtimo, NULL);
}
struct protosw *
pffindtype(family, type)
int family;
int type;
{
register struct domain *dp;
register struct protosw *pr;
for (dp = domains; dp; dp = dp->dom_next)
if (dp->dom_family == family)
goto found;
return (0);
found:
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_type && pr->pr_type == type)
return (pr);
return (0);
}
struct protosw *
pffindproto(family, protocol, type)
int family;
int protocol;
int type;
{
register struct domain *dp;
register struct protosw *pr;
struct protosw *maybe = 0;
if (family == 0)
return (0);
for (dp = domains; dp; dp = dp->dom_next)
if (dp->dom_family == family)
goto found;
return (0);
found:
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
if ((pr->pr_protocol == protocol) && (pr->pr_type == type))
return (pr);
if (type == SOCK_RAW && pr->pr_type == SOCK_RAW &&
pr->pr_protocol == 0 && maybe == (struct protosw *)0)
maybe = pr;
}
return (maybe);
}
/*
* The caller must make sure that the new protocol is fully set up and ready to
* accept requests before it is registered.
*/
int
pf_proto_register(family, npr)
int family;
struct protosw *npr;
{
struct domain *dp;
struct protosw *pr, *fpr;
/* Sanity checks. */
if (family == 0)
return (EPFNOSUPPORT);
if (npr->pr_type == 0)
return (EPROTOTYPE);
if (npr->pr_protocol == 0)
return (EPROTONOSUPPORT);
if (npr->pr_usrreqs == NULL)
return (ENXIO);
/* Try to find the specified domain based on the family. */
for (dp = domains; dp; dp = dp->dom_next)
if (dp->dom_family == family)
goto found;
return (EPFNOSUPPORT);
found:
/* Initialize backpointer to struct domain. */
npr->pr_domain = dp;
fpr = NULL;
/* The new protocol must not yet exist. */
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
if ((pr->pr_type == npr->pr_type) &&
(pr->pr_protocol == npr->pr_protocol))
return (EEXIST); /* XXX: Check only protocol? */
/* While here, remember the first free spacer. */
if ((fpr == NULL) && (pr->pr_protocol == PROTO_SPACER))
fpr = pr;
}
/* If no free spacer is found we can't add the new protocol. */
if (fpr == NULL)
return (ENOMEM);
/* Copy the new struct protosw over the spacer. */
bcopy(npr, fpr, sizeof(*fpr));
/* Initialize and activate the protocol. */
if (fpr->pr_init)
(fpr->pr_init)();
return (0);
}
/*
* The caller must make sure the protocol and its functions correctly shut down
* all sockets and release all locks and memory references.
*/
int
pf_proto_unregister(family, protocol, type)
int family;
int protocol;
int type;
{
struct domain *dp;
struct protosw *pr, *dpr;
/* Sanity checks. */
if (family == 0)
return (EPFNOSUPPORT);
if (protocol == 0)
return (EPROTONOSUPPORT);
if (type == 0)
return (EPROTOTYPE);
/* Try to find the specified domain based on the family type. */
for (dp = domains; dp; dp = dp->dom_next)
if (dp->dom_family == family)
goto found;
return (EPFNOSUPPORT);
found:
dpr = NULL;
/* The protocol must exist and only once. */
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
if ((pr->pr_type == type) && (pr->pr_protocol == protocol)) {
if (dpr != NULL)
return (EMLINK); /* Should not happen! */
else
dpr = pr;
}
}
/* Protocol does not exist. */
if (dpr == NULL)
return (EPROTONOSUPPORT);
/* De-orbit the protocol and make the slot available again. */
dpr->pr_type = 0;
dpr->pr_domain = dp;
dpr->pr_protocol = PROTO_SPACER;
dpr->pr_flags = 0;
dpr->pr_input = NULL;
dpr->pr_output = NULL;
dpr->pr_ctlinput = NULL;
dpr->pr_ctloutput = NULL;
dpr->pr_ousrreq = NULL;
dpr->pr_init = NULL;
dpr->pr_fasttimo = NULL;
dpr->pr_slowtimo = NULL;
dpr->pr_drain = NULL;
dpr->pr_usrreqs = &nousrreqs;
return (0);
}
void
pfctlinput(cmd, sa)
int cmd;
struct sockaddr *sa;
{
register struct domain *dp;
register struct protosw *pr;
for (dp = domains; dp; dp = dp->dom_next)
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_ctlinput)
(*pr->pr_ctlinput)(cmd, sa, (void *)0);
}
void
pfctlinput2(cmd, sa, ctlparam)
int cmd;
struct sockaddr *sa;
void *ctlparam;
{
struct domain *dp;
struct protosw *pr;
if (!sa)
return;
for (dp = domains; dp; dp = dp->dom_next) {
/*
* the check must be made by xx_ctlinput() anyways, to
* make sure we use data item pointed to by ctlparam in
* correct way. the following check is made just for safety.
*/
if (dp->dom_family != sa->sa_family)
continue;
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_ctlinput)
(*pr->pr_ctlinput)(cmd, sa, ctlparam);
}
}
static void
pfslowtimo(arg)
void *arg;
{
register struct domain *dp;
register struct protosw *pr;
NET_ASSERT_GIANT();
for (dp = domains; dp; dp = dp->dom_next)
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_slowtimo)
(*pr->pr_slowtimo)();
callout_reset(&pfslow_callout, hz/2, pfslowtimo, NULL);
}
static void
pffasttimo(arg)
void *arg;
{
register struct domain *dp;
register struct protosw *pr;
NET_ASSERT_GIANT();
for (dp = domains; dp; dp = dp->dom_next)
for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
if (pr->pr_fasttimo)
(*pr->pr_fasttimo)();
callout_reset(&pffast_callout, hz/5, pffasttimo, NULL);
}
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