uipc_domain.c

Go to the documentation of this file.

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 * 3. 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/eventhandler.h>
#include <sys/epoch.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/rmlock.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
 
#include <machine/atomic.h>
 
#include <net/vnet.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_DOMAININIT, SI_ORDER_ANY, domaininit, NULL);
 
static void domainfinalize(void *);
SYSINIT(domainfin, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_FIRST, domainfinalize,
    NULL);
 
static struct callout pffast_callout;
static struct callout pfslow_callout;
 
static void     pffasttimo(void *);
static void     pfslowtimo(void *);
 
static struct rmlock pftimo_lock;
RM_SYSINIT(pftimo_lock, &pftimo_lock, "pftimo");
 
static LIST_HEAD(, protosw) pffast_list =
    LIST_HEAD_INITIALIZER(pffast_list);
static LIST_HEAD(, protosw) pfslow_list =
    LIST_HEAD_INITIALIZER(pfslow_list);
 
struct domain *domains;         /* registered protocol domains */
int domain_init_status = 0;
static 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_accept =           pru_accept_notsupp,
        .pru_attach =           pru_attach_notsupp,
        .pru_bind =             pru_bind_notsupp,
        .pru_connect =          pru_connect_notsupp,
        .pru_connect2 =         pru_connect2_notsupp,
        .pru_control =          pru_control_notsupp,
        .pru_disconnect =       pru_disconnect_notsupp,
        .pru_listen =           pru_listen_notsupp,
        .pru_peeraddr =         pru_peeraddr_notsupp,
        .pru_rcvd =             pru_rcvd_notsupp,
        .pru_rcvoob =           pru_rcvoob_notsupp,
        .pru_send =             pru_send_notsupp,
        .pru_sense =            pru_sense_null,
        .pru_shutdown =         pru_shutdown_notsupp,
        .pru_sockaddr =         pru_sockaddr_notsupp,
        .pru_sosend =           pru_sosend_notsupp,
        .pru_soreceive =        pru_soreceive_notsupp,
        .pru_sopoll =           pru_sopoll_notsupp,
};
 
static void
pr_usrreqs_init(struct protosw *pr)
{
        struct pr_usrreqs *pu;
 
        pu = pr->pr_usrreqs;
        KASSERT(pu != NULL, ("%s: %ssw[%d] has no usrreqs!", __func__,
            pr->pr_domain->dom_name,
            (int)(pr - pr->pr_domain->dom_protosw)));
 
        /*
         * Protocol switch methods fall into three categories: mandatory,
         * mandatory but protosw_init() provides a default, and optional.
         *
         * For true protocols (i.e., pru_attach != NULL), KASSERT truly
         * mandatory methods with no defaults, and initialize defaults for
         * other mandatory methods if the protocol hasn't defined an
         * implementation (NULL function pointer).
         */
#if 0
        if (pu->pru_attach != NULL) {
                KASSERT(pu->pru_abort != NULL,
                    ("protosw_init: %ssw[%d] pru_abort NULL",
                    pr->pr_domain->dom_name,
                    (int)(pr - pr->pr_domain->dom_protosw)));
                KASSERT(pu->pru_send != NULL,
                    ("protosw_init: %ssw[%d] pru_send NULL",
                    pr->pr_domain->dom_name,
                    (int)(pr - pr->pr_domain->dom_protosw)));
        }
#endif
 
#define DEFAULT(foo, bar)       if ((foo) == NULL)  (foo) = (bar)
        DEFAULT(pu->pru_accept, pru_accept_notsupp);
        DEFAULT(pu->pru_aio_queue, pru_aio_queue_notsupp);
        DEFAULT(pu->pru_bind, pru_bind_notsupp);
        DEFAULT(pu->pru_bindat, pru_bindat_notsupp);
        DEFAULT(pu->pru_connect, pru_connect_notsupp);
        DEFAULT(pu->pru_connect2, pru_connect2_notsupp);
        DEFAULT(pu->pru_connectat, pru_connectat_notsupp);
        DEFAULT(pu->pru_control, pru_control_notsupp);
        DEFAULT(pu->pru_disconnect, pru_disconnect_notsupp);
        DEFAULT(pu->pru_listen, pru_listen_notsupp);
        DEFAULT(pu->pru_peeraddr, pru_peeraddr_notsupp);
        DEFAULT(pu->pru_rcvd, pru_rcvd_notsupp);
        DEFAULT(pu->pru_rcvoob, pru_rcvoob_notsupp);
        DEFAULT(pu->pru_sense, pru_sense_null);
        DEFAULT(pu->pru_shutdown, pru_shutdown_notsupp);
        DEFAULT(pu->pru_sockaddr, pru_sockaddr_notsupp);
        DEFAULT(pu->pru_sosend, sosend_generic);
        DEFAULT(pu->pru_soreceive, soreceive_generic);
        DEFAULT(pu->pru_sopoll, sopoll_generic);
        DEFAULT(pu->pru_ready, pru_ready_notsupp);
#undef DEFAULT
}
 
/*
 * 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
domain_init(void *arg)
{
        struct domain *dp = arg;
        struct protosw *pr;
        int flags;
 
        MPASS(IS_DEFAULT_VNET(curvnet));
 
        flags = atomic_load_acq_int(&dp->dom_flags);
        if ((flags & DOMF_SUPPORTED) == 0)
                return;
        MPASS((flags & DOMF_INITED) == 0);
 
        for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++) {
                pr_usrreqs_init(pr);
                rm_wlock(&pftimo_lock);
                if (pr->pr_fasttimo != NULL)
                        LIST_INSERT_HEAD(&pffast_list, pr, pr_fasttimos);
                if (pr->pr_slowtimo != NULL)
                        LIST_INSERT_HEAD(&pfslow_list, pr, pr_slowtimos);
                rm_wunlock(&pftimo_lock);
        }
 
        /*
         * update global information about maximums
         */
        max_hdr = max_linkhdr + max_protohdr;
        max_datalen = MHLEN - max_hdr;
        if (max_datalen < 1)
                panic("%s: max_datalen < 1", __func__);
        atomic_set_rel_int(&dp->dom_flags, DOMF_INITED);
}
 
/*
 * 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
domain_add(void *data)
{
        struct domain *dp;
 
        dp = (struct domain *)data;
        if (dp->dom_probe != NULL && (*dp->dom_probe)() != 0)
                return;
        atomic_set_rel_int(&dp->dom_flags, DOMF_SUPPORTED);
        mtx_lock(&dom_mtx);
        dp->dom_next = domains;
        domains = dp;
 
        KASSERT(domain_init_status >= 1,
            ("attempt to domain_add(%s) before domaininit()",
            dp->dom_name));
#ifndef INVARIANTS
        if (domain_init_status < 1)
                printf("WARNING: attempt to domain_add(%s) before "
                    "domaininit()\n", dp->dom_name);
#endif
        mtx_unlock(&dom_mtx);
}
 
/* ARGSUSED*/
static void
domaininit(void *dummy)
{
 
        if (max_linkhdr < 16)           /* XXX */
                max_linkhdr = 16;
 
        callout_init(&pffast_callout, 1);
        callout_init(&pfslow_callout, 1);
 
        mtx_lock(&dom_mtx);
        KASSERT(domain_init_status == 0, ("domaininit called too late!"));
        domain_init_status = 1;
        mtx_unlock(&dom_mtx);
}
 
/* ARGSUSED*/
static void
domainfinalize(void *dummy)
{
 
        mtx_lock(&dom_mtx);
        KASSERT(domain_init_status == 1, ("domainfinalize called too late!"));
        domain_init_status = 2;
        mtx_unlock(&dom_mtx);   
 
        callout_reset(&pffast_callout, 1, pffasttimo, NULL);
        callout_reset(&pfslow_callout, 1, pfslowtimo, NULL);
}
 
struct domain *
pffinddomain(int family)
{
        struct domain *dp;
 
        for (dp = domains; dp != NULL; dp = dp->dom_next)
                if (dp->dom_family == family)
                        return (dp);
        return (NULL);
}
 
struct protosw *
pffindtype(int family, int type)
{
        struct domain *dp;
        struct protosw *pr;
 
        dp = pffinddomain(family);
        if (dp == NULL)
                return (NULL);
 
        for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
                if (pr->pr_type && pr->pr_type == type)
                        return (pr);
        return (NULL);
}
 
struct protosw *
pffindproto(int family, int protocol, int type)
{
        struct domain *dp;
        struct protosw *pr;
        struct protosw *maybe;
 
        maybe = NULL;
        if (family == 0)
                return (NULL);
 
        dp = pffinddomain(family);
        if (dp == NULL)
                return (NULL);
 
        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 == NULL)
                        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(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. */
        dp = pffinddomain(family);
        if (dp == NULL)
                return (EPFNOSUPPORT);
 
        /* Initialize backpointer to struct domain. */
        npr->pr_domain = dp;
        fpr = NULL;
 
        /*
         * Protect us against races when two protocol registrations for
         * the same protocol happen at the same time.
         */
        mtx_lock(&dom_mtx);
 
        /* 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)) {
                        mtx_unlock(&dom_mtx);
                        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) {
                mtx_unlock(&dom_mtx);
                return (ENOMEM);
        }
 
        /* Copy the new struct protosw over the spacer. */
        bcopy(npr, fpr, sizeof(*fpr));
 
        pr_usrreqs_init(fpr);
        rm_wlock(&pftimo_lock);
        if (fpr->pr_fasttimo != NULL)
                LIST_INSERT_HEAD(&pffast_list, fpr, pr_fasttimos);
        if (fpr->pr_slowtimo != NULL)
                LIST_INSERT_HEAD(&pfslow_list, fpr, pr_slowtimos);
        rm_wunlock(&pftimo_lock);
 
        /* Job is done, no more protection required. */
        mtx_unlock(&dom_mtx);
 
        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(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. */
        dp = pffinddomain(family);
        if (dp == NULL)
                return (EPFNOSUPPORT);
 
        dpr = NULL;
 
        /* Lock out everyone else while we are manipulating the protosw. */
        mtx_lock(&dom_mtx);
 
        /* 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) {
                                mtx_unlock(&dom_mtx);
                                return (EMLINK);   /* Should not happen! */
                        } else
                                dpr = pr;
                }
        }
 
        /* Protocol does not exist. */
        if (dpr == NULL) {
                mtx_unlock(&dom_mtx);
                return (EPROTONOSUPPORT);
        }
 
        rm_wlock(&pftimo_lock);
        if (dpr->pr_fasttimo != NULL)
                LIST_REMOVE(dpr, pr_fasttimos);
        if (dpr->pr_slowtimo != NULL)
                LIST_REMOVE(dpr, pr_slowtimos);
        rm_wunlock(&pftimo_lock);
 
        /* 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_fasttimo = NULL;
        dpr->pr_slowtimo = NULL;
        dpr->pr_drain = NULL;
        dpr->pr_usrreqs = &nousrreqs;
 
        /* Job is done, not more protection required. */
        mtx_unlock(&dom_mtx);
 
        return (0);
}
 
void
pfctlinput(int cmd, struct sockaddr *sa)
{
        struct domain *dp;
        struct protosw *pr;
 
        NET_EPOCH_ASSERT();
 
        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);
}
 
static void
pfslowtimo(void *arg)
{
        struct rm_priotracker tracker;
        struct epoch_tracker et;
        struct protosw *pr;
 
        rm_rlock(&pftimo_lock, &tracker);
        NET_EPOCH_ENTER(et);
        LIST_FOREACH(pr, &pfslow_list, pr_slowtimos) {
                (*pr->pr_slowtimo)();
        }
        NET_EPOCH_EXIT(et);
        rm_runlock(&pftimo_lock, &tracker);
        callout_reset(&pfslow_callout, hz/2, pfslowtimo, NULL);
}
 
static void
pffasttimo(void *arg)
{
        struct rm_priotracker tracker;
        struct epoch_tracker et;
        struct protosw *pr;
 
        rm_rlock(&pftimo_lock, &tracker);
        NET_EPOCH_ENTER(et);
        LIST_FOREACH(pr, &pffast_list, pr_fasttimos) {
                (*pr->pr_fasttimo)();
        }
        NET_EPOCH_EXIT(et);
        rm_runlock(&pftimo_lock, &tracker);
        callout_reset(&pffast_callout, hz/5, pffasttimo, NULL);
}