318 lines
7.3 KiB
C
318 lines
7.3 KiB
C
/*-
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* Copyright (c) 2010-2013 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This material is based upon work partially supported by The
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* NetBSD Foundation under a contract with Mindaugas Rasiukevicius.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* NPF interface for the Application Level Gateways (ALGs).
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*/
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#ifdef _KERNEL
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: npf_alg.c,v 1.18 2018/09/29 14:41:36 rmind Exp $");
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/kmem.h>
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#include <sys/pserialize.h>
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#include <sys/psref.h>
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#include <sys/mutex.h>
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#include <net/pfil.h>
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#include <sys/module.h>
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#endif
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#include "npf_impl.h"
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/*
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* NAT ALG description structure. For more compact use of cache,
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* the functions are separated in their own arrays. The number of
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* ALGs is expected to be very small.
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*/
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struct npf_alg {
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const char * na_name;
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u_int na_slot;
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};
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struct npf_algset {
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/* List of ALGs and the count. */
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npf_alg_t alg_list[NPF_MAX_ALGS];
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u_int alg_count;
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/* Matching, inspection and translation functions. */
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npfa_funcs_t alg_funcs[NPF_MAX_ALGS];
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/* Passive reference until we npf conn lookup is pserialize-safe. */
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struct psref_target alg_psref[NPF_MAX_ALGS];
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};
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static const char alg_prefix[] = "npf_alg_";
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#define NPF_EXT_PREFLEN (sizeof(alg_prefix) - 1)
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__read_mostly static struct psref_class * npf_alg_psref_class = NULL;
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void
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npf_alg_sysinit(void)
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{
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npf_alg_psref_class = psref_class_create("npf_alg", IPL_SOFTNET);
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}
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void
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npf_alg_sysfini(void)
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{
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psref_class_destroy(npf_alg_psref_class);
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npf_alg_psref_class = NULL;
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}
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void
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npf_alg_init(npf_t *npf)
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{
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npf_algset_t *aset;
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aset = kmem_zalloc(sizeof(npf_algset_t), KM_SLEEP);
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npf->algset = aset;
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}
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void
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npf_alg_fini(npf_t *npf)
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{
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npf_algset_t *aset = npf->algset;
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kmem_free(aset, sizeof(npf_algset_t));
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}
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static npf_alg_t *
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npf_alg_lookup(npf_t *npf, const char *name)
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{
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npf_algset_t *aset = npf->algset;
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KASSERT(npf_config_locked_p(npf));
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for (u_int i = 0; i < aset->alg_count; i++) {
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npf_alg_t *alg = &aset->alg_list[i];
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const char *aname = alg->na_name;
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if (aname && strcmp(aname, name) == 0)
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return alg;
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}
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return NULL;
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}
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npf_alg_t *
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npf_alg_construct(npf_t *npf, const char *name)
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{
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npf_alg_t *alg;
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npf_config_enter(npf);
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if ((alg = npf_alg_lookup(npf, name)) == NULL) {
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char modname[NPF_EXT_PREFLEN + 64];
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snprintf(modname, sizeof(modname), "%s%s", alg_prefix, name);
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npf_config_exit(npf);
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if (module_autoload(modname, MODULE_CLASS_MISC) != 0) {
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return NULL;
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}
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npf_config_enter(npf);
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alg = npf_alg_lookup(npf, name);
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}
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npf_config_exit(npf);
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return alg;
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}
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/*
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* npf_alg_register: register application-level gateway.
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*/
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npf_alg_t *
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npf_alg_register(npf_t *npf, const char *name, const npfa_funcs_t *funcs)
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{
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npf_algset_t *aset = npf->algset;
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npfa_funcs_t *afuncs;
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npf_alg_t *alg;
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u_int i;
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npf_config_enter(npf);
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if (npf_alg_lookup(npf, name) != NULL) {
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npf_config_exit(npf);
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return NULL;
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}
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/* Find a spare slot. */
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for (i = 0; i < NPF_MAX_ALGS; i++) {
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alg = &aset->alg_list[i];
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if (alg->na_name == NULL) {
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break;
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}
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}
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if (i == NPF_MAX_ALGS) {
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npf_config_exit(npf);
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return NULL;
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}
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/* Register the ALG. */
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alg->na_name = name;
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alg->na_slot = i;
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/* Prepare a psref target. */
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psref_target_init(&aset->alg_psref[i], npf_alg_psref_class);
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membar_producer();
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/* Assign the functions. */
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afuncs = &aset->alg_funcs[i];
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afuncs->match = funcs->match;
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afuncs->translate = funcs->translate;
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afuncs->inspect = funcs->inspect;
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aset->alg_count = MAX(aset->alg_count, i + 1);
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npf_config_exit(npf);
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return alg;
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}
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/*
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* npf_alg_unregister: unregister application-level gateway.
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*/
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int
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npf_alg_unregister(npf_t *npf, npf_alg_t *alg)
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{
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npf_algset_t *aset = npf->algset;
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u_int i = alg->na_slot;
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npfa_funcs_t *afuncs;
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/* Deactivate the functions first. */
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npf_config_enter(npf);
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afuncs = &aset->alg_funcs[i];
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afuncs->match = NULL;
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afuncs->translate = NULL;
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afuncs->inspect = NULL;
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pserialize_perform(npf->qsbr);
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psref_target_destroy(&aset->alg_psref[i], npf_alg_psref_class);
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/* Finally, unregister the ALG. */
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npf_ruleset_freealg(npf_config_natset(npf), alg);
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alg->na_name = NULL;
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npf_config_exit(npf);
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return 0;
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}
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/*
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* npf_alg_match: call ALG matching inspectors, determine if any ALG matches.
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*/
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bool
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npf_alg_match(npf_cache_t *npc, npf_nat_t *nt, int di)
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{
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npf_algset_t *aset = npc->npc_ctx->algset;
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bool match = false;
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int s;
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s = pserialize_read_enter();
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for (u_int i = 0; i < aset->alg_count; i++) {
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const npfa_funcs_t *f = &aset->alg_funcs[i];
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if (f->match && f->match(npc, nt, di)) {
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match = true;
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break;
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}
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}
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pserialize_read_exit(s);
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return match;
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}
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/*
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* npf_alg_exec: execute ALG hooks for translation.
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*/
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void
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npf_alg_exec(npf_cache_t *npc, npf_nat_t *nt, bool forw)
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{
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npf_algset_t *aset = npc->npc_ctx->algset;
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int s;
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s = pserialize_read_enter();
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for (u_int i = 0; i < aset->alg_count; i++) {
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const npfa_funcs_t *f = &aset->alg_funcs[i];
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if (f->translate) {
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f->translate(npc, nt, forw);
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}
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}
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pserialize_read_exit(s);
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}
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npf_conn_t *
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npf_alg_conn(npf_cache_t *npc, int di)
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{
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npf_algset_t *aset = npc->npc_ctx->algset;
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npf_conn_t *con = NULL;
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struct psref psref;
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int s;
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s = pserialize_read_enter();
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for (u_int i = 0; i < aset->alg_count; i++) {
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const npfa_funcs_t *f = &aset->alg_funcs[i];
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struct psref_target *psref_target = &aset->alg_psref[i];
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if (!f->inspect)
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continue;
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membar_consumer();
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psref_acquire(&psref, psref_target, npf_alg_psref_class);
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pserialize_read_exit(s);
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con = f->inspect(npc, di);
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s = pserialize_read_enter();
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psref_release(&psref, psref_target, npf_alg_psref_class);
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if (con != NULL)
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break;
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}
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pserialize_read_exit(s);
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return con;
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}
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int
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npf_alg_export(npf_t *npf, nvlist_t *npf_dict)
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{
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npf_algset_t *aset = npf->algset;
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KASSERT(npf_config_locked_p(npf));
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for (u_int i = 0; i < aset->alg_count; i++) {
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const npf_alg_t *alg = &aset->alg_list[i];
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nvlist_t *algdict;
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if (alg->na_name == NULL) {
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continue;
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}
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algdict = nvlist_create(0);
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nvlist_add_string(algdict, "name", alg->na_name);
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nvlist_append_nvlist_array(npf_dict, "algs", algdict);
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nvlist_destroy(algdict);
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}
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return 0;
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}
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