138889Sjdp/*- 238889Sjdp * Copyright (c) 2000 Paycounter, Inc. 360484Sobrien * Copyright (c) 2005 Robert N. M. Watson 460484Sobrien * Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org> 560484Sobrien * All rights reserved. 638889Sjdp * 738889Sjdp * Redistribution and use in source and binary forms, with or without 860484Sobrien * modification, are permitted provided that the following conditions 938889Sjdp * are met: 1038889Sjdp * 1. Redistributions of source code must retain the above copyright 1138889Sjdp * notice, this list of conditions and the following disclaimer. 1260484Sobrien * 2. Redistributions in binary form must reproduce the above copyright 1360484Sobrien * notice, this list of conditions and the following disclaimer in the 1438889Sjdp * documentation and/or other materials provided with the distribution. 1577298Sobrien * 1677298Sobrien * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1777298Sobrien * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1860484Sobrien * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1938889Sjdp * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 2038889Sjdp * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2138889Sjdp * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2238889Sjdp * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2338889Sjdp * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2438889Sjdp * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2538889Sjdp * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2638889Sjdp * SUCH DAMAGE. 2738889Sjdp */ 2838889Sjdp 2938889Sjdp#include <sys/cdefs.h> 3038889Sjdp__FBSDID("$FreeBSD$"); 3138889Sjdp 3238889Sjdp#define ACCEPT_FILTER_MOD 3338889Sjdp 3438889Sjdp#include "opt_param.h" 3538889Sjdp#include <sys/param.h> 3638889Sjdp#include <sys/systm.h> 3738889Sjdp#include <sys/domain.h> 3838889Sjdp#include <sys/kernel.h> 3938889Sjdp#include <sys/lock.h> 4038889Sjdp#include <sys/malloc.h> 4138889Sjdp#include <sys/mbuf.h> 4238889Sjdp#include <sys/module.h> 4338889Sjdp#include <sys/mutex.h> 4460484Sobrien#include <sys/protosw.h> 4577298Sobrien#include <sys/sysctl.h> 4638889Sjdp#include <sys/socket.h> 4760484Sobrien#include <sys/socketvar.h> 4860484Sobrien#include <sys/queue.h> 4938889Sjdp 5038889Sjdpstatic struct mtx accept_filter_mtx; 5138889SjdpMTX_SYSINIT(accept_filter, &accept_filter_mtx, "accept_filter_mtx", 5277298Sobrien MTX_DEF); 5360484Sobrien#define ACCEPT_FILTER_LOCK() mtx_lock(&accept_filter_mtx) 5438889Sjdp#define ACCEPT_FILTER_UNLOCK() mtx_unlock(&accept_filter_mtx) 5538889Sjdp 5638889Sjdpstatic SLIST_HEAD(, accept_filter) accept_filtlsthd = 5738889Sjdp SLIST_HEAD_INITIALIZER(accept_filtlsthd); 5877298Sobrien 5938889SjdpMALLOC_DEFINE(M_ACCF, "accf", "accept filter data"); 6038889Sjdp 6160484Sobrienstatic int unloadable = 0; 6238889Sjdp 6338889SjdpSYSCTL_DECL(_net_inet); /* XXX: some header should do this for me */ 6438889SjdpSYSCTL_NODE(_net_inet, OID_AUTO, accf, CTLFLAG_RW, 0, "Accept filters"); 6538889SjdpSYSCTL_INT(_net_inet_accf, OID_AUTO, unloadable, CTLFLAG_RW, &unloadable, 0, 6660484Sobrien "Allow unload of accept filters (not recommended)"); 6738889Sjdp 6838889Sjdp/* 6938889Sjdp * Must be passed a malloc'd structure so we don't explode if the kld is 7038889Sjdp * unloaded, we leak the struct on deallocation to deal with this, but if a 7138889Sjdp * filter is loaded with the same name as a leaked one we re-use the entry. 7277298Sobrien */ 7360484Sobrienint 7438889Sjdpaccept_filt_add(struct accept_filter *filt) 7538889Sjdp{ 7638889Sjdp struct accept_filter *p; 7738889Sjdp 7838889Sjdp ACCEPT_FILTER_LOCK(); 7938889Sjdp SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 8078828Sobrien if (strcmp(p->accf_name, filt->accf_name) == 0) { 8138889Sjdp if (p->accf_callback != NULL) { 8238889Sjdp ACCEPT_FILTER_UNLOCK(); 8338889Sjdp return (EEXIST); 8438889Sjdp } else { 8538889Sjdp p->accf_callback = filt->accf_callback; 8638889Sjdp ACCEPT_FILTER_UNLOCK(); 8738889Sjdp free(filt, M_ACCF); 8838889Sjdp return (0); 8938889Sjdp } 9038889Sjdp } 9138889Sjdp 9238889Sjdp if (p == NULL) 9338889Sjdp SLIST_INSERT_HEAD(&accept_filtlsthd, filt, accf_next); 9438889Sjdp ACCEPT_FILTER_UNLOCK(); 9538889Sjdp return (0); 9638889Sjdp} 9738889Sjdp 9838889Sjdpint 9938889Sjdpaccept_filt_del(char *name) 10038889Sjdp{ 10138889Sjdp struct accept_filter *p; 10238889Sjdp 10377298Sobrien p = accept_filt_get(name); 10438889Sjdp if (p == NULL) 10538889Sjdp return (ENOENT); 10638889Sjdp 10738889Sjdp p->accf_callback = NULL; 10838889Sjdp return (0); 10938889Sjdp} 11077298Sobrien 11177298Sobrienstruct accept_filter * 11277298Sobrienaccept_filt_get(char *name) 11377298Sobrien{ 11477298Sobrien struct accept_filter *p; 11538889Sjdp 11638889Sjdp ACCEPT_FILTER_LOCK(); 11738889Sjdp SLIST_FOREACH(p, &accept_filtlsthd, accf_next) 11838889Sjdp if (strcmp(p->accf_name, name) == 0) 11938889Sjdp break; 12038889Sjdp ACCEPT_FILTER_UNLOCK(); 12138889Sjdp 12238889Sjdp return (p); 12338889Sjdp} 12438889Sjdp 12538889Sjdpint 12638889Sjdpaccept_filt_generic_mod_event(module_t mod, int event, void *data) 12738889Sjdp{ 12838889Sjdp struct accept_filter *p; 12938889Sjdp struct accept_filter *accfp = (struct accept_filter *) data; 13038889Sjdp int error; 13138889Sjdp 13238889Sjdp switch (event) { 13338889Sjdp case MOD_LOAD: 13460484Sobrien p = malloc(sizeof(*p), M_ACCF, 13538889Sjdp M_WAITOK); 13677298Sobrien bcopy(accfp, p, sizeof(*p)); 13760484Sobrien error = accept_filt_add(p); 13860484Sobrien break; 13938889Sjdp 14060484Sobrien case MOD_UNLOAD: 14160484Sobrien /* 14260484Sobrien * Do not support unloading yet. we don't keep track of 14377298Sobrien * refcounts and unloading an accept filter callback and then 14460484Sobrien * having it called is a bad thing. A simple fix would be to 14577298Sobrien * track the refcount in the struct accept_filter. 14677298Sobrien */ 14777298Sobrien if (unloadable != 0) { 14877298Sobrien error = accept_filt_del(accfp->accf_name); 14960484Sobrien } else 15060484Sobrien error = EOPNOTSUPP; 15160484Sobrien break; 15260484Sobrien 15360484Sobrien case MOD_SHUTDOWN: 15438889Sjdp error = 0; 15538889Sjdp break; 15638889Sjdp 15738889Sjdp default: 15838889Sjdp error = EOPNOTSUPP; 15938889Sjdp break; 16038889Sjdp } 16138889Sjdp 16238889Sjdp return (error); 16338889Sjdp} 16438889Sjdp 16560484Sobrienint 16638889Sjdpdo_getopt_accept_filter(struct socket *so, struct sockopt *sopt) 16738889Sjdp{ 16838889Sjdp struct accept_filter_arg *afap; 16938889Sjdp int error; 17038889Sjdp 17138889Sjdp error = 0; 17238889Sjdp afap = malloc(sizeof(*afap), M_TEMP, 17338889Sjdp M_WAITOK | M_ZERO); 17438889Sjdp SOCK_LOCK(so); 17538889Sjdp if ((so->so_options & SO_ACCEPTCONN) == 0) { 17638889Sjdp error = EINVAL; 17738889Sjdp goto out; 17838889Sjdp } 17938889Sjdp if ((so->so_options & SO_ACCEPTFILTER) == 0) { 18038889Sjdp error = EINVAL; 18138889Sjdp goto out; 18238889Sjdp } 18338889Sjdp strcpy(afap->af_name, so->so_accf->so_accept_filter->accf_name); 18438889Sjdp if (so->so_accf->so_accept_filter_str != NULL) 18538889Sjdp strcpy(afap->af_arg, so->so_accf->so_accept_filter_str); 18638889Sjdpout: 18738889Sjdp SOCK_UNLOCK(so); 18838889Sjdp if (error == 0) 18938889Sjdp error = sooptcopyout(sopt, afap, sizeof(*afap)); 19038889Sjdp free(afap, M_TEMP); 19138889Sjdp return (error); 19260484Sobrien} 19338889Sjdp 19438889Sjdpint 19560484Sobriendo_setopt_accept_filter(struct socket *so, struct sockopt *sopt) 19660484Sobrien{ 19738889Sjdp struct accept_filter_arg *afap; 19838889Sjdp struct accept_filter *afp; 19938889Sjdp struct so_accf *newaf; 20038889Sjdp int error = 0; 20138889Sjdp 20238889Sjdp /* 20338889Sjdp * Handle the simple delete case first. 20438889Sjdp */ 20538889Sjdp if (sopt == NULL || sopt->sopt_val == NULL) { 20638889Sjdp SOCK_LOCK(so); 20738889Sjdp if ((so->so_options & SO_ACCEPTCONN) == 0) { 20838889Sjdp SOCK_UNLOCK(so); 20938889Sjdp return (EINVAL); 21038889Sjdp } 21138889Sjdp if (so->so_accf != NULL) { 21238889Sjdp struct so_accf *af = so->so_accf; 21338889Sjdp if (af->so_accept_filter != NULL && 21438889Sjdp af->so_accept_filter->accf_destroy != NULL) { 21538889Sjdp af->so_accept_filter->accf_destroy(so); 21638889Sjdp } 21738889Sjdp if (af->so_accept_filter_str != NULL) 21838889Sjdp free(af->so_accept_filter_str, M_ACCF); 21938889Sjdp free(af, M_ACCF); 22038889Sjdp so->so_accf = NULL; 22138889Sjdp } 22238889Sjdp so->so_options &= ~SO_ACCEPTFILTER; 22338889Sjdp SOCK_UNLOCK(so); 22438889Sjdp return (0); 22560484Sobrien } 22677298Sobrien 22738889Sjdp /* 22860484Sobrien * Pre-allocate any memory we may need later to avoid blocking at 22960484Sobrien * untimely moments. This does not optimize for invalid arguments. 23038889Sjdp */ 23138889Sjdp afap = malloc(sizeof(*afap), M_TEMP, 23238889Sjdp M_WAITOK); 23377298Sobrien error = sooptcopyin(sopt, afap, sizeof *afap, sizeof *afap); 23460484Sobrien afap->af_name[sizeof(afap->af_name)-1] = '\0'; 23538889Sjdp afap->af_arg[sizeof(afap->af_arg)-1] = '\0'; 23638889Sjdp if (error) { 23738889Sjdp free(afap, M_TEMP); 23838889Sjdp return (error); 23977298Sobrien } 24038889Sjdp afp = accept_filt_get(afap->af_name); 24138889Sjdp if (afp == NULL) { 24260484Sobrien free(afap, M_TEMP); 24338889Sjdp return (ENOENT); 24438889Sjdp } 24538889Sjdp /* 24638889Sjdp * Allocate the new accept filter instance storage. We may 24760484Sobrien * have to free it again later if we fail to attach it. If 24838889Sjdp * attached properly, 'newaf' is NULLed to avoid a free() 24938889Sjdp * while in use. 25038889Sjdp */ 25138889Sjdp newaf = malloc(sizeof(*newaf), M_ACCF, M_WAITOK | 25238889Sjdp M_ZERO); 25377298Sobrien if (afp->accf_create != NULL && afap->af_name[0] != '\0') { 25460484Sobrien int len = strlen(afap->af_name) + 1; 25538889Sjdp newaf->so_accept_filter_str = malloc(len, M_ACCF, 25638889Sjdp M_WAITOK); 25738889Sjdp strcpy(newaf->so_accept_filter_str, afap->af_name); 25838889Sjdp } 25938889Sjdp 26038889Sjdp /* 26138889Sjdp * Require a listen socket; don't try to replace an existing filter 26238889Sjdp * without first removing it. 26338889Sjdp */ 26438889Sjdp SOCK_LOCK(so); 26560484Sobrien if (((so->so_options & SO_ACCEPTCONN) == 0) || 26677298Sobrien (so->so_accf != NULL)) { 26738889Sjdp error = EINVAL; 26860484Sobrien goto out; 26960484Sobrien } 27038889Sjdp 27138889Sjdp /* 27238889Sjdp * Invoke the accf_create() method of the filter if required. The 27377298Sobrien * socket mutex is held over this call, so create methods for filters 27460484Sobrien * can't block. 27538889Sjdp */ 27638889Sjdp if (afp->accf_create != NULL) { 27738889Sjdp newaf->so_accept_filter_arg = 27838889Sjdp afp->accf_create(so, afap->af_arg); 27977298Sobrien if (newaf->so_accept_filter_arg == NULL) { 28038889Sjdp error = EINVAL; 28138889Sjdp goto out; 28260484Sobrien } 28338889Sjdp } 28438889Sjdp newaf->so_accept_filter = afp; 28538889Sjdp so->so_accf = newaf; 28638889Sjdp so->so_options |= SO_ACCEPTFILTER; 28760484Sobrien newaf = NULL; 28838889Sjdpout: 28938889Sjdp SOCK_UNLOCK(so); 29038889Sjdp if (newaf != NULL) { 29138889Sjdp if (newaf->so_accept_filter_str != NULL) 29238889Sjdp free(newaf->so_accept_filter_str, M_ACCF); 29377298Sobrien free(newaf, M_ACCF); 29460484Sobrien } 29538889Sjdp if (afap != NULL) 29638889Sjdp free(afap, M_TEMP); 29738889Sjdp return (error); 29838889Sjdp} 29938889Sjdp