/*
 * Copyright (c) 2001-2003
 *	Fraunhofer Institute for Open Communication Systems (FhG Fokus).
 *	All rights reserved.
 *
 * Author: Harti Brandt <harti@freebsd.org>
 * 
 * Copyright (c) 2010 The FreeBSD Foundation
 * All rights reserved.
 *
 * Portions of this software were developed by Shteryana Sotirova Shopova
 * under sponsorship from the FreeBSD Foundation.
 *
 * 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.
 * 
 * THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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.
 *
 * $Begemot: bsnmp/snmpd/main.c,v 1.100 2006/02/14 09:04:20 brandt_h Exp $
 *
 * SNMPd main stuff.
 */

#include <sys/queue.h>
#include <sys/param.h>
#include <sys/un.h>
#include <sys/ucred.h>
#include <sys/uio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include <errno.h>
#include <syslog.h>
#include <unistd.h>
#include <signal.h>
#include <dlfcn.h>
#include <inttypes.h>

#ifdef USE_TCPWRAPPERS
#include <arpa/inet.h>
#include <tcpd.h>
#endif

#include "support.h"
#include "snmpmod.h"
#include "snmpd.h"
#include "tree.h"
#include "oid.h"

#define	PATH_PID	"/var/run/%s.pid"
#define PATH_CONFIG	"/etc/%s.config"
#define	PATH_ENGINE	"/var/%s.engine"

uint64_t this_tick;	/* start of processing of current packet (absolute) */
uint64_t start_tick;	/* start of processing */

struct systemg systemg = {
	NULL,
	{ 8, { 1, 3, 6, 1, 4, 1, 1115, 7352 }},
	NULL, NULL, NULL,
	64 + 8 + 4,
	0
};
struct debug debug = {
	0,		/* dump_pdus */
	LOG_DEBUG,	/* log_pri */
	0,		/* evdebug */
};

struct snmpd snmpd = {
	2048,		/* txbuf */
	2048,		/* rxbuf */
	0,		/* comm_dis */
	0,		/* auth_traps */
	{0, 0, 0, 0},	/* trap1addr */
	VERS_ENABLE_ALL,/* version_enable */
};
struct snmpd_stats snmpd_stats;

struct snmpd_usmstat snmpd_usmstats;

/* snmpEngine */
struct snmp_engine snmpd_engine;

/* snmpSerialNo */
int32_t snmp_serial_no;

struct snmpd_target_stats snmpd_target_stats;

/* search path for config files */
const char *syspath = PATH_SYSCONFIG;

/* list of all loaded modules */
struct lmodules lmodules = TAILQ_HEAD_INITIALIZER(lmodules);

/* list of loaded modules during start-up in the order they were loaded */
static struct lmodules modules_start = TAILQ_HEAD_INITIALIZER(modules_start);

/* list of all known communities */
struct community_list community_list = TAILQ_HEAD_INITIALIZER(community_list);

/* list of all known USM users */
struct usm_userlist usm_userlist = SLIST_HEAD_INITIALIZER(usm_userlist);

/* A list of all VACM users configured, including v1, v2c and v3 */
struct vacm_userlist vacm_userlist = SLIST_HEAD_INITIALIZER(vacm_userlist);

/* A list of all VACM groups */
struct vacm_grouplist vacm_grouplist = SLIST_HEAD_INITIALIZER(vacm_grouplist);

static struct vacm_group vacm_default_group = {
	.groupname = "",
};

/* The list of configured access entries */
struct vacm_accesslist vacm_accesslist = TAILQ_HEAD_INITIALIZER(vacm_accesslist);

/* The list of configured views */
struct vacm_viewlist vacm_viewlist = SLIST_HEAD_INITIALIZER(vacm_viewlist);

/* The list of configured contexts */
struct vacm_contextlist vacm_contextlist =
    SLIST_HEAD_INITIALIZER(vacm_contextlist);

/* list of all installed object resources */
struct objres_list objres_list = TAILQ_HEAD_INITIALIZER(objres_list);

/* community value generator */
static u_int next_community_index = 1;

/* list of all known ranges */
struct idrange_list idrange_list = TAILQ_HEAD_INITIALIZER(idrange_list);

/* identifier generator */
u_int next_idrange = 1;

/* list of all current timers */
struct timer_list timer_list = LIST_HEAD_INITIALIZER(timer_list);

/* list of file descriptors */
struct fdesc_list fdesc_list = LIST_HEAD_INITIALIZER(fdesc_list);

/* program arguments */
static char **progargs;
static int nprogargs;

/* current community */
u_int	community;
static struct community *comm;

/* current USM user */
struct usm_user *usm_user;

/* file names */
static char config_file[MAXPATHLEN + 1];
static char pid_file[MAXPATHLEN + 1];
char engine_file[MAXPATHLEN + 1];

#ifndef USE_LIBBEGEMOT
/* event context */
static evContext evctx;
#endif

/* signal mask */
static sigset_t blocked_sigs;

/* signal handling */
static int work;
#define	WORK_DOINFO	0x0001
#define	WORK_RECONFIG	0x0002

/* oids */
static const struct asn_oid
	oid_snmpMIB = OIDX_snmpMIB,
	oid_begemotSnmpd = OIDX_begemotSnmpd,
	oid_coldStart = OIDX_coldStart,
	oid_authenticationFailure = OIDX_authenticationFailure;

const struct asn_oid oid_zeroDotZero = { 2, { 0, 0 }};

const struct asn_oid oid_usmUnknownEngineIDs =
	{ 11, { 1, 3, 6, 1, 6, 3, 15, 1, 1, 4, 0}};

const struct asn_oid oid_usmNotInTimeWindows =
	{ 11, { 1, 3, 6, 1, 6, 3, 15, 1, 1, 2, 0}};

/* request id generator for traps */
u_int trap_reqid;

/* help text */
static const char usgtxt[] = "\
Begemot simple SNMP daemon. Copyright (c) 2001-2002 Fraunhofer Institute for\n\
Open Communication Systems (FhG Fokus). All rights reserved.\n\
Copyright (c) 2010 The FreeBSD Foundation. All rights reserved.\n\
usage: snmpd [-dh] [-c file] [-D options] [-e file] [-I path]\n\
             [-l prefix] [-m variable=value] [-p file]\n\
options:\n\
  -d		don't daemonize\n\
  -h		print this info\n\
  -c file	specify configuration file\n\
  -D options	debugging options\n\
  -e file	specify engine id file\n\
  -I path	system include path\n\
  -l prefix	default basename for pid and config file\n\
  -m var=val	define variable\n\
  -p file	specify pid file\n\
";

/* hosts_access(3) request */
#ifdef USE_TCPWRAPPERS
static struct request_info req;
#endif

/* transports */
extern const struct transport_def udp_trans;
extern const struct transport_def lsock_trans;

struct transport_list transport_list = TAILQ_HEAD_INITIALIZER(transport_list);

/* forward declarations */
static void snmp_printf_func(const char *fmt, ...);
static void snmp_error_func(const char *err, ...);
static void snmp_debug_func(const char *err, ...);
static void asn_error_func(const struct asn_buf *b, const char *err, ...);

/*
 * Allocate rx/tx buffer. We allocate one byte more for rx.
 */
void *
buf_alloc(int tx)
{
	void *buf;

	if ((buf = malloc(tx ? snmpd.txbuf : snmpd.rxbuf)) == NULL) {
		syslog(LOG_CRIT, "cannot allocate buffer");
		if (tx)
			snmpd_stats.noTxbuf++;
		else
			snmpd_stats.noRxbuf++;
		return (NULL);
	}
	return (buf);
}

/*
 * Return the buffer size.
 */
size_t
buf_size(int tx)
{
	return (tx ? snmpd.txbuf : snmpd.rxbuf);
}

/*
 * Prepare a PDU for output
 */
void
snmp_output(struct snmp_pdu *pdu, u_char *sndbuf, size_t *sndlen,
    const char *dest)
{
	struct asn_buf resp_b;

	resp_b.asn_ptr = sndbuf;
	resp_b.asn_len = snmpd.txbuf;

	if (snmp_pdu_encode(pdu, &resp_b) != 0) {
		syslog(LOG_ERR, "cannot encode message");
		abort();
	}
	if (debug.dump_pdus) {
		snmp_printf("%s <- ", dest);
		snmp_pdu_dump(pdu);
	}
	*sndlen = (size_t)(resp_b.asn_ptr - sndbuf);
}

/*
 * Check USM PDU header credentials against local SNMP Engine & users.
 */
static enum snmp_code
snmp_pdu_auth_user(struct snmp_pdu *pdu)
{
	uint64_t etime;
	usm_user = NULL;

	/* un-authenticated snmpEngineId discovery */
	if (pdu->engine.engine_len == 0 && strlen(pdu->user.sec_name) == 0) {
		pdu->engine.engine_len = snmpd_engine.engine_len;
		memcpy(pdu->engine.engine_id, snmpd_engine.engine_id,
		    snmpd_engine.engine_len);
		pdu->engine.engine_boots = snmpd_engine.engine_boots;
		pdu->engine.engine_time = snmpd_engine.engine_time;
		pdu->flags |= SNMP_MSG_AUTODISCOVER;
		return (SNMP_CODE_OK);
	}

	if ((usm_user = usm_find_user(pdu->engine.engine_id,
	    pdu->engine.engine_len, pdu->user.sec_name)) == NULL ||
	    usm_user->status != 1 /* active */)
		return (SNMP_CODE_BADUSER);

	if (usm_user->user_engine_len != snmpd_engine.engine_len ||
	    memcmp(usm_user->user_engine_id, snmpd_engine.engine_id,
	    snmpd_engine.engine_len) != 0)
		return (SNMP_CODE_BADENGINE);

	pdu->user.priv_proto = usm_user->suser.priv_proto;
	memcpy(pdu->user.priv_key, usm_user->suser.priv_key,
	    sizeof(pdu->user.priv_key));

	/* authenticated snmpEngineId discovery */
	if ((pdu->flags & SNMP_MSG_AUTH_FLAG) != 0) {
		etime = (get_ticks() - start_tick)  / 100ULL;
		if (etime < INT32_MAX)
			snmpd_engine.engine_time = etime;
		else {
			start_tick = get_ticks();
			set_snmpd_engine();
			snmpd_engine.engine_time = start_tick;
		}

		pdu->user.auth_proto = usm_user->suser.auth_proto;
		memcpy(pdu->user.auth_key, usm_user->suser.auth_key,
		    sizeof(pdu->user.auth_key));

		if (pdu->engine.engine_boots == 0 &&
		    pdu->engine.engine_time == 0) {
		    	pdu->flags |= SNMP_MSG_AUTODISCOVER;
			return (SNMP_CODE_OK);
		}

		if (pdu->engine.engine_boots != snmpd_engine.engine_boots ||
		    abs(pdu->engine.engine_time - snmpd_engine.engine_time) >
		    SNMP_TIME_WINDOW)
			return (SNMP_CODE_NOTINTIME);
	}

	if (((pdu->flags & SNMP_MSG_PRIV_FLAG) != 0 &&
	    (pdu->flags & SNMP_MSG_AUTH_FLAG) == 0) ||
	    ((pdu->flags & SNMP_MSG_AUTH_FLAG) == 0 &&
	    usm_user->suser.auth_proto != SNMP_AUTH_NOAUTH) ||
	    ((pdu->flags & SNMP_MSG_PRIV_FLAG) == 0 &&
	    usm_user->suser.priv_proto != SNMP_PRIV_NOPRIV))
		return (SNMP_CODE_BADSECLEVEL);

	return (SNMP_CODE_OK);
}

/*
 * Check whether access to each of var bindings in the PDU is allowed based
 * on the user credentials against the configured User groups & VACM views.
 */
enum snmp_code
snmp_pdu_auth_access(struct snmp_pdu *pdu, int32_t *ip)
{
	const char *uname;
	int32_t suboid, smodel;
	uint32_t i;
	struct vacm_user *vuser;
	struct vacm_access *acl;
	struct vacm_context *vacmctx;
	struct vacm_view *view;

	/*
	 * At least a default context exists if the snmpd_vacm(3) module is
	 * running.
	 */
	if (SLIST_EMPTY(&vacm_contextlist) ||
	    (pdu->flags & SNMP_MSG_AUTODISCOVER) != 0)
		return (SNMP_CODE_OK);

	switch (pdu->version) {
	case SNMP_V1:
		if ((uname = comm_string(community)) == NULL)
			return (SNMP_CODE_FAILED);
		smodel = SNMP_SECMODEL_SNMPv1;
		break;

	case SNMP_V2c:
		if ((uname = comm_string(community)) == NULL)
			return (SNMP_CODE_FAILED);
		smodel = SNMP_SECMODEL_SNMPv2c;
		break;

	case SNMP_V3:
		uname = pdu->user.sec_name;
		if ((smodel = pdu->security_model) !=  SNMP_SECMODEL_USM)
			return (SNMP_CODE_FAILED);
		/* Compare the PDU context engine id against the agent's */
		if (pdu->context_engine_len != snmpd_engine.engine_len ||
		    memcmp(pdu->context_engine, snmpd_engine.engine_id,
		    snmpd_engine.engine_len) != 0)
			return (SNMP_CODE_FAILED);
		break;

	default:
		abort();
	}

	SLIST_FOREACH(vuser, &vacm_userlist, vvu)
		if (strcmp(uname, vuser->secname) == 0 &&
		    vuser->sec_model == smodel)
			break;

	if (vuser == NULL || vuser->group == NULL)
		return (SNMP_CODE_FAILED);

	/* XXX: shteryana - recheck */
	TAILQ_FOREACH_REVERSE(acl, &vacm_accesslist, vacm_accesslist, vva) {
		if (acl->group != vuser->group)
			continue;
		SLIST_FOREACH(vacmctx, &vacm_contextlist, vcl)
			if (memcmp(vacmctx->ctxname, acl->ctx_prefix,
			    acl->ctx_match) == 0)
				goto match;
	}

	return (SNMP_CODE_FAILED);

match:

	switch (pdu->type) {
	case SNMP_PDU_GET:
	case SNMP_PDU_GETNEXT:
	case SNMP_PDU_GETBULK:
		if ((view = acl->read_view) == NULL)
			return (SNMP_CODE_FAILED);
		break;

	case SNMP_PDU_SET:
		if ((view = acl->write_view) == NULL)
			return (SNMP_CODE_FAILED);
		break;

	case SNMP_PDU_TRAP:
	case SNMP_PDU_INFORM:
	case SNMP_PDU_TRAP2:
	case SNMP_PDU_REPORT:
		if ((view = acl->notify_view) == NULL)
			return (SNMP_CODE_FAILED);
		break;
	case SNMP_PDU_RESPONSE:
		/* NOTREACHED */
			return (SNMP_CODE_FAILED);
	default:
		abort();
	}

	for (i = 0; i < pdu->nbindings; i++) {
		/* XXX - view->mask*/
		suboid = asn_is_suboid(&view->subtree, &pdu->bindings[i].var);
		if ((!suboid && !view->exclude) || (suboid && view->exclude)) {
			*ip = i + 1;
			return (SNMP_CODE_FAILED);
		}
	}

	return (SNMP_CODE_OK);
}

/*
 * SNMP input. Start: decode the PDU, find the user or community.
 */
enum snmpd_input_err
snmp_input_start(const u_char *buf, size_t len, const char *source,
    struct snmp_pdu *pdu, int32_t *ip, size_t *pdulen)
{
	struct asn_buf b;
	enum snmp_code code;
	enum snmpd_input_err ret;
	int sret;

	/* update uptime */
	this_tick = get_ticks();

	b.asn_cptr = buf;
	b.asn_len = len;

	/* look whether we have enough bytes for the entire PDU. */
	switch (sret = snmp_pdu_snoop(&b)) {

	  case 0:
		return (SNMPD_INPUT_TRUNC);

	  case -1:
		snmpd_stats.inASNParseErrs++;
		return (SNMPD_INPUT_FAILED);
	}
	b.asn_len = *pdulen = (size_t)sret;

	memset(pdu, 0, sizeof(*pdu));
	if ((code = snmp_pdu_decode_header(&b, pdu)) != SNMP_CODE_OK)
		goto decoded;

	if (pdu->version == SNMP_V3) {
		if (pdu->security_model != SNMP_SECMODEL_USM) {
			code = SNMP_CODE_FAILED;
			goto decoded;
		}
		if ((code = snmp_pdu_auth_user(pdu)) != SNMP_CODE_OK)
		    	goto decoded;
		if ((code =  snmp_pdu_decode_secmode(&b, pdu)) != SNMP_CODE_OK)
			goto decoded;
	}
	code = snmp_pdu_decode_scoped(&b, pdu, ip);

	ret = SNMPD_INPUT_OK;

decoded:
	snmpd_stats.inPkts++;

	switch (code) {

	  case SNMP_CODE_FAILED:
		snmpd_stats.inASNParseErrs++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_BADVERS:
	  bad_vers:
		snmpd_stats.inBadVersions++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_BADLEN:
		if (pdu->type == SNMP_OP_SET)
			ret = SNMPD_INPUT_VALBADLEN;
		break;

	  case SNMP_CODE_OORANGE:
		if (pdu->type == SNMP_OP_SET)
			ret = SNMPD_INPUT_VALRANGE;
		break;

	  case SNMP_CODE_BADENC:
		if (pdu->type == SNMP_OP_SET)
			ret = SNMPD_INPUT_VALBADENC;
		break;

	  case SNMP_CODE_BADSECLEVEL:
		snmpd_usmstats.unsupported_seclevels++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_NOTINTIME:
		snmpd_usmstats.not_in_time_windows++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_BADUSER:
		snmpd_usmstats.unknown_users++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_BADENGINE:
		snmpd_usmstats.unknown_engine_ids++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_BADDIGEST:
		snmpd_usmstats.wrong_digests++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_EDECRYPT:
		snmpd_usmstats.decrypt_errors++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_CODE_OK:
		switch (pdu->version) {

		  case SNMP_V1:
			if (!(snmpd.version_enable & VERS_ENABLE_V1))
				goto bad_vers;
			break;

		  case SNMP_V2c:
			if (!(snmpd.version_enable & VERS_ENABLE_V2C))
				goto bad_vers;
			break;

		  case SNMP_V3:
		  	if (!(snmpd.version_enable & VERS_ENABLE_V3))
				goto bad_vers;
			break;

		  case SNMP_Verr:
			goto bad_vers;
		}
		break;
	}

	if (debug.dump_pdus) {
		snmp_printf("%s -> ", source);
		snmp_pdu_dump(pdu);
	}

	/*
	 * Look, whether we know the community or user
	 */

	if (pdu->version != SNMP_V3) {
		TAILQ_FOREACH(comm, &community_list, link)
			if (comm->string != NULL &&
			    strcmp(comm->string, pdu->community) == 0)
				break;

		if (comm == NULL) {
			snmpd_stats.inBadCommunityNames++;
			snmp_pdu_free(pdu);
			if (snmpd.auth_traps)
				snmp_send_trap(&oid_authenticationFailure,
				    (struct snmp_value *)NULL);
			ret = SNMPD_INPUT_BAD_COMM;
		} else
			community = comm->value;
	} else if (pdu->nbindings == 0) {
		/* RFC 3414 - snmpEngineID Discovery */
		if (strlen(pdu->user.sec_name) == 0) {
			asn_append_oid(&(pdu->bindings[pdu->nbindings++].var),
			    &oid_usmUnknownEngineIDs);
			pdu->context_engine_len = snmpd_engine.engine_len;
			memcpy(pdu->context_engine, snmpd_engine.engine_id,
			    snmpd_engine.engine_len);
		} else if (pdu->engine.engine_boots == 0 &&
		    pdu->engine.engine_time == 0) {
			asn_append_oid(&(pdu->bindings[pdu->nbindings++].var),
			    &oid_usmNotInTimeWindows);
			pdu->engine.engine_boots = snmpd_engine.engine_boots;
			pdu->engine.engine_time = snmpd_engine.engine_time;
		}
	} else if (usm_user->suser.auth_proto != SNMP_AUTH_NOAUTH &&
	     (pdu->engine.engine_boots == 0 || pdu->engine.engine_time == 0)) {
		snmpd_usmstats.not_in_time_windows++;
		ret = SNMP_CODE_FAILED;
	}

	if ((code = snmp_pdu_auth_access(pdu, ip)) != SNMP_CODE_OK)
		ret = SNMP_CODE_FAILED;

	return (ret);
}

/*
 * Will return only _OK or _FAILED
 */
enum snmpd_input_err
snmp_input_finish(struct snmp_pdu *pdu, const u_char *rcvbuf, size_t rcvlen,
    u_char *sndbuf, size_t *sndlen, const char *source,
    enum snmpd_input_err ierr, int32_t ivar, void *data)
{
	struct snmp_pdu resp;
	struct asn_buf resp_b, pdu_b;
	enum snmp_ret ret;

	resp_b.asn_ptr = sndbuf;
	resp_b.asn_len = snmpd.txbuf;

	pdu_b.asn_cptr = rcvbuf;
	pdu_b.asn_len = rcvlen;

	if (ierr != SNMPD_INPUT_OK) {
		/* error decoding the input of a SET */
		if (pdu->version == SNMP_V1)
			pdu->error_status = SNMP_ERR_BADVALUE;
		else if (ierr == SNMPD_INPUT_VALBADLEN)
			pdu->error_status = SNMP_ERR_WRONG_LENGTH;
		else if (ierr == SNMPD_INPUT_VALRANGE)
			pdu->error_status = SNMP_ERR_WRONG_VALUE;
		else
			pdu->error_status = SNMP_ERR_WRONG_ENCODING;

		pdu->error_index = ivar;

		if (snmp_make_errresp(pdu, &pdu_b, &resp_b) == SNMP_RET_IGN) {
			syslog(LOG_WARNING, "could not encode error response");
			snmpd_stats.silentDrops++;
			return (SNMPD_INPUT_FAILED);
		}

		if (debug.dump_pdus) {
			snmp_printf("%s <- ", source);
			snmp_pdu_dump(pdu);
		}
		*sndlen = (size_t)(resp_b.asn_ptr - sndbuf);
		return (SNMPD_INPUT_OK);
	}

	switch (pdu->type) {

	  case SNMP_PDU_GET:
		ret = snmp_get(pdu, &resp_b, &resp, data);
		break;

	  case SNMP_PDU_GETNEXT:
		ret = snmp_getnext(pdu, &resp_b, &resp, data);
		break;

	  case SNMP_PDU_SET:
		ret = snmp_set(pdu, &resp_b, &resp, data);
		break;

	  case SNMP_PDU_GETBULK:
		ret = snmp_getbulk(pdu, &resp_b, &resp, data);
		break;

	  default:
		ret = SNMP_RET_IGN;
		break;
	}

	switch (ret) {

	  case SNMP_RET_OK:
		/* normal return - send a response */
		if (debug.dump_pdus) {
			snmp_printf("%s <- ", source);
			snmp_pdu_dump(&resp);
		}
		*sndlen = (size_t)(resp_b.asn_ptr - sndbuf);
		snmp_pdu_free(&resp);
		return (SNMPD_INPUT_OK);

	  case SNMP_RET_IGN:
		/* error - send nothing */
		snmpd_stats.silentDrops++;
		return (SNMPD_INPUT_FAILED);

	  case SNMP_RET_ERR:
		/* error - send error response. The snmp routine has
		 * changed the error fields in the original message. */
		resp_b.asn_ptr = sndbuf;
		resp_b.asn_len = snmpd.txbuf;
		if (snmp_make_errresp(pdu, &pdu_b, &resp_b) == SNMP_RET_IGN) {
			syslog(LOG_WARNING, "could not encode error response");
			snmpd_stats.silentDrops++;
			return (SNMPD_INPUT_FAILED);
		} else {
			if (debug.dump_pdus) {
				snmp_printf("%s <- ", source);
				snmp_pdu_dump(pdu);
			}
			*sndlen = (size_t)(resp_b.asn_ptr - sndbuf);
			return (SNMPD_INPUT_OK);
		}
	}
	abort();
}

/*
 * Insert a port into the right place in the transport's table of ports
 */
void
trans_insert_port(struct transport *t, struct tport *port)
{
	struct tport *p;

	TAILQ_FOREACH(p, &t->table, link) {
		if (asn_compare_oid(&p->index, &port->index) > 0) {
			TAILQ_INSERT_BEFORE(p, port, link);
			return;
		}
	}
	port->transport = t;
	TAILQ_INSERT_TAIL(&t->table, port, link);
}

/*
 * Remove a port from a transport's list
 */
void
trans_remove_port(struct tport *port)
{

	TAILQ_REMOVE(&port->transport->table, port, link);
}

/*
 * Find a port on a transport's list
 */
struct tport *
trans_find_port(struct transport *t, const struct asn_oid *idx, u_int sub)
{

	return (FIND_OBJECT_OID(&t->table, idx, sub));
}

/*
 * Find next port on a transport's list
 */
struct tport *
trans_next_port(struct transport *t, const struct asn_oid *idx, u_int sub)
{

	return (NEXT_OBJECT_OID(&t->table, idx, sub));
}

/*
 * Return first port
 */
struct tport *
trans_first_port(struct transport *t)
{

	return (TAILQ_FIRST(&t->table));
}

/*
 * Iterate through all ports until a function returns a 0.
 */
struct tport *
trans_iter_port(struct transport *t, int (*func)(struct tport *, intptr_t),
    intptr_t arg)
{
	struct tport *p;

	TAILQ_FOREACH(p, &t->table, link)
		if (func(p, arg) == 0)
			return (p);
	return (NULL);
}

/*
 * Register a transport
 */
int
trans_register(const struct transport_def *def, struct transport **pp)
{
	u_int i;
	char or_descr[256];

	if ((*pp = malloc(sizeof(**pp))) == NULL)
		return (SNMP_ERR_GENERR);

	/* construct index */
	(*pp)->index.len = strlen(def->name) + 1;
	(*pp)->index.subs[0] = strlen(def->name);
	for (i = 0; i < (*pp)->index.subs[0]; i++)
		(*pp)->index.subs[i + 1] = def->name[i];

	(*pp)->vtab = def;

	if (FIND_OBJECT_OID(&transport_list, &(*pp)->index, 0) != NULL) {
		free(*pp);
		return (SNMP_ERR_INCONS_VALUE);
	}

	/* register module */
	snprintf(or_descr, sizeof(or_descr), "%s transport mapping", def->name);
	if (((*pp)->or_index = or_register(&def->id, or_descr, NULL)) == 0) {
		free(*pp);
		return (SNMP_ERR_GENERR);
	}

	INSERT_OBJECT_OID((*pp), &transport_list);

	TAILQ_INIT(&(*pp)->table);

	return (SNMP_ERR_NOERROR);
}

/*
 * Unregister transport
 */
int
trans_unregister(struct transport *t)
{
	if (!TAILQ_EMPTY(&t->table))
		return (SNMP_ERR_INCONS_VALUE);

	or_unregister(t->or_index);
	TAILQ_REMOVE(&transport_list, t, link);

	return (SNMP_ERR_NOERROR);
}

/*
 * File descriptor support
 */
#ifdef USE_LIBBEGEMOT
static void
input(int fd, int mask __unused, void *uap)
#else
static void
input(evContext ctx __unused, void *uap, int fd, int mask __unused)
#endif
{
	struct fdesc *f = uap;

	(*f->func)(fd, f->udata);
}

void
fd_suspend(void *p)
{
	struct fdesc *f = p;

#ifdef USE_LIBBEGEMOT
	if (f->id >= 0) {
		poll_unregister(f->id);
		f->id = -1;
	}
#else
	if (evTestID(f->id)) {
		(void)evDeselectFD(evctx, f->id);
		evInitID(&f->id);
	}
#endif
}

int
fd_resume(void *p)
{
	struct fdesc *f = p;
	int err;

#ifdef USE_LIBBEGEMOT
	if (f->id >= 0)
		return (0);
	if ((f->id = poll_register(f->fd, input, f, POLL_IN)) < 0) {
		err = errno;
		syslog(LOG_ERR, "select fd %d: %m", f->fd);
		errno = err;
		return (-1);
	}
#else
	if (evTestID(f->id))
		return (0);
	if (evSelectFD(evctx, f->fd, EV_READ, input, f, &f->id)) {
		err = errno;
		syslog(LOG_ERR, "select fd %d: %m", f->fd);
		errno = err;
		return (-1);
	}
#endif
	return (0);
}

void *
fd_select(int fd, void (*func)(int, void *), void *udata, struct lmodule *mod)
{
	struct fdesc *f;
	int err;

	if ((f = malloc(sizeof(struct fdesc))) == NULL) {
		err = errno;
		syslog(LOG_ERR, "fd_select: %m");
		errno = err;
		return (NULL);
	}
	f->fd = fd;
	f->func = func;
	f->udata = udata;
	f->owner = mod;
#ifdef USE_LIBBEGEMOT
	f->id = -1;
#else
	evInitID(&f->id);
#endif

	if (fd_resume(f)) {
		err = errno;
		free(f);
		errno = err;
		return (NULL);
	}

	LIST_INSERT_HEAD(&fdesc_list, f, link);

	return (f);
}

void
fd_deselect(void *p)
{
	struct fdesc *f = p;

	LIST_REMOVE(f, link);
	fd_suspend(f);
	free(f);
}

static void
fd_flush(struct lmodule *mod)
{
	struct fdesc *t, *t1;

	t = LIST_FIRST(&fdesc_list);
	while (t != NULL) {
		t1 = LIST_NEXT(t, link);
		if (t->owner == mod)
			fd_deselect(t);
		t = t1;
	}
}

/*
 * Consume a message from the input buffer
 */
static void
snmp_input_consume(struct port_input *pi)
{
	if (!pi->stream) {
		/* always consume everything */
		pi->length = 0;
		return;
	}
	if (pi->consumed >= pi->length) {
		/* all bytes consumed */
		pi->length = 0;
		return;
	}
	memmove(pi->buf, pi->buf + pi->consumed, pi->length - pi->consumed);
	pi->length -= pi->consumed;
}

static void
check_priv_dgram(struct port_input *pi, struct sockcred *cred)
{

	/* process explicitly sends credentials */
	if (cred)
		pi->priv = (cred->sc_euid == 0);
	else
		pi->priv = 0;
}

static void
check_priv_stream(struct port_input *pi)
{
	struct xucred ucred;
	socklen_t ucredlen;

	/* obtain the accept time credentials */
	ucredlen = sizeof(ucred);

	if (getsockopt(pi->fd, 0, LOCAL_PEERCRED, &ucred, &ucredlen) == 0 &&
	    ucredlen >= sizeof(ucred) && ucred.cr_version == XUCRED_VERSION)
		pi->priv = (ucred.cr_uid == 0);
	else
		pi->priv = 0;
}

/*
 * Input from a stream socket.
 */
static int
recv_stream(struct port_input *pi)
{
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t len;

	if (pi->buf == NULL) {
		/* no buffer yet - allocate one */
		if ((pi->buf = buf_alloc(0)) == NULL) {
			/* ups - could not get buffer. Return an error
			 * the caller must close the transport. */
			return (-1);
		}
		pi->buflen = buf_size(0);
		pi->consumed = 0;
		pi->length = 0;
	}

	/* try to get a message */
	msg.msg_name = pi->peer;
	msg.msg_namelen = pi->peerlen;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;
	msg.msg_control = NULL;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;

	iov[0].iov_base = pi->buf + pi->length;
	iov[0].iov_len = pi->buflen - pi->length;

	len = recvmsg(pi->fd, &msg, 0);

	if (len == -1 || len == 0)
		/* receive error */
		return (-1);

	pi->length += len;

	if (pi->cred)
		check_priv_stream(pi);

	return (0);
}

/*
 * Input from a datagram socket.
 * Each receive should return one datagram.
 */
static int
recv_dgram(struct port_input *pi, struct in_addr *laddr)
{
	u_char embuf[1000];
	char cbuf[CMSG_SPACE(SOCKCREDSIZE(CMGROUP_MAX)) +
	    CMSG_SPACE(sizeof(struct in_addr))];
	struct msghdr msg;
	struct iovec iov[1];
	ssize_t len;
	struct cmsghdr *cmsg;
	struct sockcred *cred = NULL;

	if (pi->buf == NULL) {
		/* no buffer yet - allocate one */
		if ((pi->buf = buf_alloc(0)) == NULL) {
			/* ups - could not get buffer. Read away input
			 * and drop it */
			(void)recvfrom(pi->fd, embuf, sizeof(embuf),
			    0, NULL, NULL);
			/* return error */
			return (-1);
		}
		pi->buflen = buf_size(0);
	}

	/* try to get a message */
	msg.msg_name = pi->peer;
	msg.msg_namelen = pi->peerlen;
	msg.msg_iov = iov;
	msg.msg_iovlen = 1;
	memset(cbuf, 0, sizeof(cbuf));
	msg.msg_control = cbuf;
	msg.msg_controllen = sizeof(cbuf);
	msg.msg_flags = 0;

	iov[0].iov_base = pi->buf;
	iov[0].iov_len = pi->buflen;

	len = recvmsg(pi->fd, &msg, 0);

	if (len == -1 || len == 0)
		/* receive error */
		return (-1);

	if (msg.msg_flags & MSG_TRUNC) {
		/* truncated - drop */
		snmpd_stats.silentDrops++;
		snmpd_stats.inTooLong++;
		return (-1);
	}

	pi->length = (size_t)len;

	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
	    cmsg = CMSG_NXTHDR(&msg, cmsg)) {
		if (cmsg->cmsg_level == IPPROTO_IP &&
		    cmsg->cmsg_type == IP_RECVDSTADDR)
			memcpy(laddr, CMSG_DATA(cmsg), sizeof(struct in_addr));
		if (cmsg->cmsg_level == SOL_SOCKET &&
		    cmsg->cmsg_type == SCM_CREDS)
			cred = (struct sockcred *)CMSG_DATA(cmsg);
	}

	if (pi->cred)
		check_priv_dgram(pi, cred);

	return (0);
}

/*
 * Input from a socket
 */
int
snmpd_input(struct port_input *pi, struct tport *tport)
{
	u_char *sndbuf;
	size_t sndlen;
	struct snmp_pdu pdu;
	enum snmpd_input_err ierr, ferr;
	enum snmpd_proxy_err perr;
	int32_t vi;
	int ret;
	ssize_t slen;
#ifdef USE_TCPWRAPPERS
	char client[16];
#endif
	struct msghdr msg;
	struct iovec iov[1];
	char cbuf[CMSG_SPACE(sizeof(struct in_addr))];
	struct cmsghdr *cmsgp;

	/* get input depending on the transport */
	if (pi->stream) {
		msg.msg_control = NULL;
		msg.msg_controllen = 0;

		ret = recv_stream(pi);
	} else {
		struct in_addr *laddr;

		memset(cbuf, 0, CMSG_SPACE(sizeof(struct in_addr)));
		msg.msg_control = cbuf;
		msg.msg_controllen = CMSG_SPACE(sizeof(struct in_addr));
		cmsgp = CMSG_FIRSTHDR(&msg);
		cmsgp->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
		cmsgp->cmsg_level = IPPROTO_IP;
		cmsgp->cmsg_type = IP_SENDSRCADDR;
		laddr = (struct in_addr *)CMSG_DATA(cmsgp);
		
		ret = recv_dgram(pi, laddr);

		if (laddr->s_addr == 0) {
			msg.msg_control = NULL;
			msg.msg_controllen = 0;
		}
	}

	if (ret == -1)
		return (-1);

#ifdef USE_TCPWRAPPERS
	/*
	 * In case of AF_INET{6} peer, do hosts_access(5) check.
	 */
	if (pi->peer->sa_family != AF_LOCAL &&
	    inet_ntop(pi->peer->sa_family,
	    &((const struct sockaddr_in *)(const void *)pi->peer)->sin_addr,
	    client, sizeof(client)) != NULL) {
		request_set(&req, RQ_CLIENT_ADDR, client, 0);
		if (hosts_access(&req) == 0) {
			syslog(LOG_ERR, "refused connection from %.500s",
			    eval_client(&req));
			return (-1);
		}
	} else if (pi->peer->sa_family != AF_LOCAL)
		syslog(LOG_ERR, "inet_ntop(): %m");
#endif

	/*
	 * Handle input
	 */
	ierr = snmp_input_start(pi->buf, pi->length, "SNMP", &pdu, &vi,
	    &pi->consumed);
	if (ierr == SNMPD_INPUT_TRUNC) {
		/* need more bytes. This is ok only for streaming transports.
		 * but only if we have not reached bufsiz yet. */
		if (pi->stream) {
			if (pi->length == buf_size(0)) {
				snmpd_stats.silentDrops++;
				return (-1);
			}
			return (0);
		}
		snmpd_stats.silentDrops++;
		return (-1);
	}

	/* can't check for bad SET pdus here, because a proxy may have to
	 * check the access first. We don't want to return an error response
	 * to a proxy PDU with a wrong community */
	if (ierr == SNMPD_INPUT_FAILED) {
		/* for streaming transports this is fatal */
		if (pi->stream)
			return (-1);
		snmp_input_consume(pi);
		return (0);
	}
	if (ierr == SNMPD_INPUT_BAD_COMM) {
		snmp_input_consume(pi);
		return (0);
	}

	/*
	 * If that is a module community and the module has a proxy function,
	 * the hand it over to the module.
	 */
	if (comm != NULL && comm->owner != NULL &&
	    comm->owner->config->proxy != NULL) {
		perr = (*comm->owner->config->proxy)(&pdu, tport->transport,
		    &tport->index, pi->peer, pi->peerlen, ierr, vi,
		    !pi->cred || pi->priv);

		switch (perr) {

		  case SNMPD_PROXY_OK:
			snmp_input_consume(pi);
			return (0);

		  case SNMPD_PROXY_REJ:
			break;

		  case SNMPD_PROXY_DROP:
			snmp_input_consume(pi);
			snmp_pdu_free(&pdu);
			snmpd_stats.proxyDrops++;
			return (0);

		  case SNMPD_PROXY_BADCOMM:
			snmp_input_consume(pi);
			snmp_pdu_free(&pdu);
			snmpd_stats.inBadCommunityNames++;
			if (snmpd.auth_traps)
				snmp_send_trap(&oid_authenticationFailure,
				    (struct snmp_value *)NULL);
			return (0);

		  case SNMPD_PROXY_BADCOMMUSE:
			snmp_input_consume(pi);
			snmp_pdu_free(&pdu);
			snmpd_stats.inBadCommunityUses++;
			if (snmpd.auth_traps)
				snmp_send_trap(&oid_authenticationFailure,
				    (struct snmp_value *)NULL);
			return (0);
		}
	}

	/*
	 * Check type
	 */
	if (pdu.type == SNMP_PDU_RESPONSE ||
	    pdu.type == SNMP_PDU_TRAP ||
	    pdu.type == SNMP_PDU_TRAP2) {
		snmpd_stats.silentDrops++;
		snmpd_stats.inBadPduTypes++;
		snmp_pdu_free(&pdu);
		snmp_input_consume(pi);
		return (0);
	}

	/*
	 * Check community
	 */
	if (pdu.version < SNMP_V3 &&
	    ((pi->cred && !pi->priv && pdu.type == SNMP_PDU_SET) ||
	    (community != COMM_WRITE &&
            (pdu.type == SNMP_PDU_SET || community != COMM_READ)))) {
		snmpd_stats.inBadCommunityUses++;
		snmp_pdu_free(&pdu);
		snmp_input_consume(pi);
		if (snmpd.auth_traps)
			snmp_send_trap(&oid_authenticationFailure,
			    (struct snmp_value *)NULL);
		return (0);
	}

	/*
	 * Execute it.
	 */
	if ((sndbuf = buf_alloc(1)) == NULL) {
		snmpd_stats.silentDrops++;
		snmp_pdu_free(&pdu);
		snmp_input_consume(pi);
		return (0);
	}
	ferr = snmp_input_finish(&pdu, pi->buf, pi->length,
	    sndbuf, &sndlen, "SNMP", ierr, vi, NULL);

	if (ferr == SNMPD_INPUT_OK) {
		msg.msg_name = pi->peer;
		msg.msg_namelen = pi->peerlen;
		msg.msg_iov = iov;
		msg.msg_iovlen = 1;
		msg.msg_flags = 0;
		iov[0].iov_base = sndbuf;
		iov[0].iov_len = sndlen;

		slen = sendmsg(pi->fd, &msg, 0);
		if (slen == -1)
			syslog(LOG_ERR, "sendmsg: %m");
		else if ((size_t)slen != sndlen)
			syslog(LOG_ERR, "sendmsg: short write %zu/%zu",
			    sndlen, (size_t)slen);
	}
	snmp_pdu_free(&pdu);
	free(sndbuf);
	snmp_input_consume(pi);

	return (0);
}

/*
 * Send a PDU to a given port
 */
void
snmp_send_port(void *targ, const struct asn_oid *port, struct snmp_pdu *pdu,
    const struct sockaddr *addr, socklen_t addrlen)
{
	struct transport *trans = targ;
	struct tport *tp;
	u_char *sndbuf;
	size_t sndlen;
	ssize_t len;

	TAILQ_FOREACH(tp, &trans->table, link)
		if (asn_compare_oid(port, &tp->index) == 0)
			break;
	if (tp == 0)
		return;

	if ((sndbuf = buf_alloc(1)) == NULL)
		return;

	snmp_output(pdu, sndbuf, &sndlen, "SNMP PROXY");

	len = trans->vtab->send(tp, sndbuf, sndlen, addr, addrlen);

	if (len == -1)
		syslog(LOG_ERR, "sendto: %m");
	else if ((size_t)len != sndlen)
		syslog(LOG_ERR, "sendto: short write %zu/%zu",
		    sndlen, (size_t)len);

	free(sndbuf);
}


/*
 * Close an input source
 */
void
snmpd_input_close(struct port_input *pi)
{
	if (pi->id != NULL)
		fd_deselect(pi->id);
	if (pi->fd >= 0)
		(void)close(pi->fd);
	if (pi->buf != NULL)
		free(pi->buf);
}

/*
 * Dump internal state.
 */
#ifdef USE_LIBBEGEMOT
static void
info_func(void)
#else
static void
info_func(evContext ctx __unused, void *uap __unused, const void *tag __unused)
#endif
{
	struct lmodule *m;
	u_int i;
	char buf[10000];

	syslog(LOG_DEBUG, "Dump of SNMPd %lu\n", (u_long)getpid());
	for (i = 0; i < tree_size; i++) {
		switch (tree[i].type) {

		  case SNMP_NODE_LEAF:
			sprintf(buf, "LEAF: %s %s", tree[i].name,
			    asn_oid2str(&tree[i].oid));
			break;

		  case SNMP_NODE_COLUMN:
			sprintf(buf, "COL: %s %s", tree[i].name,
			    asn_oid2str(&tree[i].oid));
			break;
		}
		syslog(LOG_DEBUG, "%s", buf);
	}

	TAILQ_FOREACH(m, &lmodules, link)
		if (m->config->dump)
			(*m->config->dump)();
}

/*
 * Re-read configuration
 */
#ifdef USE_LIBBEGEMOT
static void
config_func(void)
#else
static void
config_func(evContext ctx __unused, void *uap __unused,
    const void *tag __unused)
#endif
{
	struct lmodule *m;

	if (read_config(config_file, NULL)) {
		syslog(LOG_ERR, "error reading config file '%s'", config_file);
		return;
	}
	TAILQ_FOREACH(m, &lmodules, link)
		if (m->config->config)
			(*m->config->config)();
}

/*
 * On USR1 dump actual configuration.
 */
static void
onusr1(int s __unused)
{

	work |= WORK_DOINFO;
}
static void
onhup(int s __unused)
{

	work |= WORK_RECONFIG;
}

static void
onterm(int s __unused)
{

	/* allow clean-up */
	exit(0);
}

static void
init_sigs(void)
{
	struct sigaction sa;

	sa.sa_handler = onusr1;
	sa.sa_flags = SA_RESTART;
	sigemptyset(&sa.sa_mask);
	if (sigaction(SIGUSR1, &sa, NULL)) {
		syslog(LOG_ERR, "sigaction: %m");
		exit(1);
	}

	sa.sa_handler = onhup;
	if (sigaction(SIGHUP, &sa, NULL)) {
		syslog(LOG_ERR, "sigaction: %m");
		exit(1);
	}

	sa.sa_handler = onterm;
	sa.sa_flags = 0;
	sigemptyset(&sa.sa_mask);
	if (sigaction(SIGTERM, &sa, NULL)) {
		syslog(LOG_ERR, "sigaction: %m");
		exit(1);
	}
	if (sigaction(SIGINT, &sa, NULL)) {
		syslog(LOG_ERR, "sigaction: %m");
		exit(1);
	}
}

static void
block_sigs(void)
{
	sigset_t set;

	sigfillset(&set);
	if (sigprocmask(SIG_BLOCK, &set, &blocked_sigs) == -1) {
		syslog(LOG_ERR, "SIG_BLOCK: %m");
		exit(1);
	}
}
static void
unblock_sigs(void)
{
	if (sigprocmask(SIG_SETMASK, &blocked_sigs, NULL) == -1) {
		syslog(LOG_ERR, "SIG_SETMASK: %m");
		exit(1);
	}
}

/*
 * Shut down
 */
static void
term(void)
{
	(void)unlink(pid_file);
}

static void
trans_stop(void)
{
	struct transport *t;

	TAILQ_FOREACH(t, &transport_list, link)
		(void)t->vtab->stop(1);
}

/*
 * Define a macro from the command line
 */
static void
do_macro(char *arg)
{
	char *eq;
	int err;

	if ((eq = strchr(arg, '=')) == NULL)
		err = define_macro(arg, "");
	else {
		*eq++ = '\0';
		err = define_macro(arg, eq);
	}
	if (err == -1) {
		syslog(LOG_ERR, "cannot save macro: %m");
		exit(1);
	}
}

/*
 * Re-implement getsubopt from scratch, because the second argument is broken
 * and will not compile with WARNS=5.
 */
static int
getsubopt1(char **arg, const char *const *options, char **valp, char **optp)
{
	static const char *const delim = ",\t ";
	u_int i;
	char *ptr;

	*optp = NULL;

	/* skip leading junk */
	for (ptr = *arg; *ptr != '\0'; ptr++)
		if (strchr(delim, *ptr) == NULL)
			break;
	if (*ptr == '\0') {
		*arg = ptr;
		return (-1);
	}
	*optp = ptr;

	/* find the end of the option */
	while (*++ptr != '\0')
		if (strchr(delim, *ptr) != NULL || *ptr == '=')
			break;

	if (*ptr != '\0') {
		if (*ptr == '=') {
			*ptr++ = '\0';
			*valp = ptr;
			while (*ptr != '\0' && strchr(delim, *ptr) == NULL)
				ptr++;
			if (*ptr != '\0')
				*ptr++ = '\0';
		} else
			*ptr++ = '\0';
	}

	*arg = ptr;

	for (i = 0; *options != NULL; options++, i++)
		if (strcmp(*optp, *options) == 0)
			return (i);
	return (-1);
}

int
main(int argc, char *argv[])
{
	int opt;
	FILE *fp;
	int background = 1;
	struct tport *p;
	const char *prefix = "snmpd";
	struct lmodule *m;
	char *value = NULL, *option; /* XXX */
	struct transport *t;

#define DBG_DUMP	0
#define DBG_EVENTS	1
#define DBG_TRACE	2
	static const char *const debug_opts[] = {
		"dump",
		"events",
		"trace",
		NULL
	};

	snmp_printf = snmp_printf_func;
	snmp_error = snmp_error_func;
	snmp_debug = snmp_debug_func;
	asn_error = asn_error_func;

	while ((opt = getopt(argc, argv, "c:dD:e:hI:l:m:p:")) != EOF)
		switch (opt) {

		  case 'c':
			strlcpy(config_file, optarg, sizeof(config_file));
			break;

		  case 'd':
			background = 0;
			break;

		  case 'D':
			while (*optarg) {
				switch (getsubopt1(&optarg, debug_opts,
				    &value, &option)) {

				  case DBG_DUMP:
					debug.dump_pdus = 1;
					break;

				  case DBG_EVENTS:
					debug.evdebug++;
					break;

				  case DBG_TRACE:
					if (value == NULL)
						syslog(LOG_ERR,
						    "no value for 'trace'");
					else
						snmp_trace = strtoul(value,
						    NULL, 0);
					break;

				  case -1:
					if (suboptarg)
						syslog(LOG_ERR,
						    "unknown debug flag '%s'",
						    option);
					else
						syslog(LOG_ERR,
						    "missing debug flag");
					break;
				}
			}
			break;

		  case 'e':
			strlcpy(engine_file, optarg, sizeof(engine_file));
			break;
		  case 'h':
			fprintf(stderr, "%s", usgtxt);
			exit(0);

		  case 'I':
			syspath = optarg;
			break;

		  case 'l':
			prefix = optarg;
			break;

		  case 'm':
			do_macro(optarg);
			break;

		  case 'p':
			strlcpy(pid_file, optarg, sizeof(pid_file));
			break;
		}

	openlog(prefix, LOG_PID | (background ? 0 : LOG_PERROR), LOG_USER);
	setlogmask(LOG_UPTO(debug.logpri - 1));

	if (background && daemon(0, 0) < 0) {
		syslog(LOG_ERR, "daemon: %m");
		exit(1);
	}

	argc -= optind;
	argv += optind;

	progargs = argv;
	nprogargs = argc;

	srandomdev();

	snmp_serial_no = random();

#ifdef USE_TCPWRAPPERS
	/*
	 * Initialize hosts_access(3) handler.
	 */
	request_init(&req, RQ_DAEMON, "snmpd", 0);
	sock_methods(&req);
#endif

	/*
	 * Initialize the tree.
	 */
	if ((tree = malloc(sizeof(struct snmp_node) * CTREE_SIZE)) == NULL) {
		syslog(LOG_ERR, "%m");
		exit(1);
	}
	memcpy(tree, ctree, sizeof(struct snmp_node) * CTREE_SIZE);
	tree_size = CTREE_SIZE;

	/*
	 * Get standard communities
	 */
	(void)comm_define(1, "SNMP read", NULL, NULL);
	(void)comm_define(2, "SNMP write", NULL, NULL);
	community = COMM_INITIALIZE;

	trap_reqid = reqid_allocate(512, NULL);

	if (config_file[0] == '\0')
		snprintf(config_file, sizeof(config_file), PATH_CONFIG, prefix);

	init_actvals();
	init_snmpd_engine();

	this_tick = get_ticks();
	start_tick = this_tick;

	/* start transports */
	if (atexit(trans_stop) == -1) {
		syslog(LOG_ERR, "atexit failed: %m");
		exit(1);
	}
	if (udp_trans.start() != SNMP_ERR_NOERROR)
		syslog(LOG_WARNING, "cannot start UDP transport");
	if (lsock_trans.start() != SNMP_ERR_NOERROR)
		syslog(LOG_WARNING, "cannot start LSOCK transport");

#ifdef USE_LIBBEGEMOT
	if (debug.evdebug > 0)
		rpoll_trace = 1;
#else
	if (evCreate(&evctx)) {
		syslog(LOG_ERR, "evCreate: %m");
		exit(1);
	}
	if (debug.evdebug > 0)
		evSetDebug(evctx, 10, stderr);
#endif

	if (engine_file[0] == '\0')
		snprintf(engine_file, sizeof(engine_file), PATH_ENGINE, prefix);

	if (read_config(config_file, NULL)) {
		syslog(LOG_ERR, "error in config file");
		exit(1);
	}

	TAILQ_FOREACH(t, &transport_list, link)
		TAILQ_FOREACH(p, &t->table, link)
			t->vtab->init_port(p);

	init_sigs();

	if (pid_file[0] == '\0')
		snprintf(pid_file, sizeof(pid_file), PATH_PID, prefix);

	if ((fp = fopen(pid_file, "w")) != NULL) {
		fprintf(fp, "%u", getpid());
		fclose(fp);
		if (atexit(term) == -1) {
			syslog(LOG_ERR, "atexit failed: %m");
			(void)remove(pid_file);
			exit(0);
		}
	}

	if (or_register(&oid_snmpMIB, "The MIB module for SNMPv2 entities.",
	    NULL) == 0) {
		syslog(LOG_ERR, "cannot register SNMPv2 MIB");
		exit(1);
	}
	if (or_register(&oid_begemotSnmpd, "The MIB module for the Begemot SNMPd.",
	    NULL) == 0) {
		syslog(LOG_ERR, "cannot register begemotSnmpd MIB");
		exit(1);
	}

	while ((m = TAILQ_FIRST(&modules_start)) != NULL) {
		m->flags &= ~LM_ONSTARTLIST;
		TAILQ_REMOVE(&modules_start, m, start);
		lm_start(m);
	}

	snmp_send_trap(&oid_coldStart, (struct snmp_value *)NULL);

	for (;;) {
#ifndef USE_LIBBEGEMOT
		evEvent event;
#endif
		struct lmodule *mod;

		TAILQ_FOREACH(mod, &lmodules, link)
			if (mod->config->idle != NULL)
				(*mod->config->idle)();

#ifndef USE_LIBBEGEMOT
		if (evGetNext(evctx, &event, EV_WAIT) == 0) {
			if (evDispatch(evctx, event))
				syslog(LOG_ERR, "evDispatch: %m");
		} else if (errno != EINTR) {
			syslog(LOG_ERR, "evGetNext: %m");
			exit(1);
		}
#else
		poll_dispatch(1);
#endif

		if (work != 0) {
			block_sigs();
			if (work & WORK_DOINFO) {
#ifdef USE_LIBBEGEMOT
				info_func();
#else
				if (evWaitFor(evctx, &work, info_func,
				    NULL, NULL) == -1) {
					syslog(LOG_ERR, "evWaitFor: %m");
					exit(1);
				}
#endif
			}
			if (work & WORK_RECONFIG) {
#ifdef USE_LIBBEGEMOT
				config_func();
#else
				if (evWaitFor(evctx, &work, config_func,
				    NULL, NULL) == -1) {
					syslog(LOG_ERR, "evWaitFor: %m");
					exit(1);
				}
#endif
			}
			work = 0;
			unblock_sigs();
#ifndef USE_LIBBEGEMOT
			if (evDo(evctx, &work) == -1) {
				syslog(LOG_ERR, "evDo: %m");
				exit(1);
			}
#endif
		}
	}

	return (0);
}

uint64_t
get_ticks(void)
{
	struct timeval tv;
	uint64_t ret;

	if (gettimeofday(&tv, NULL))
		abort();
	ret = tv.tv_sec * 100ULL + tv.tv_usec / 10000ULL;
	return (ret);
}

/*
 * Timer support
 */

/*
 * Trampoline for the non-repeatable timers.
 */
#ifdef USE_LIBBEGEMOT
static void
tfunc(int tid __unused, void *uap)
#else
static void
tfunc(evContext ctx __unused, void *uap, struct timespec due __unused,
	struct timespec inter __unused)
#endif
{
	struct timer *tp = uap;

	LIST_REMOVE(tp, link);
	tp->func(tp->udata);
	free(tp);
}

/*
 * Trampoline for the repeatable timers.
 */
#ifdef USE_LIBBEGEMOT
static void
trfunc(int tid __unused, void *uap)
#else
static void
trfunc(evContext ctx __unused, void *uap, struct timespec due __unused,
	struct timespec inter __unused)
#endif
{
	struct timer *tp = uap;

	tp->func(tp->udata);
}

/*
 * Start a one-shot timer
 */
void *
timer_start(u_int ticks, void (*func)(void *), void *udata, struct lmodule *mod)
{
	struct timer *tp;
#ifndef USE_LIBBEGEMOT
	struct timespec due;
#endif

	if ((tp = malloc(sizeof(struct timer))) == NULL) {
		syslog(LOG_CRIT, "out of memory for timer");
		exit(1);
	}

#ifndef USE_LIBBEGEMOT
	due = evAddTime(evNowTime(),
	    evConsTime(ticks / 100, (ticks % 100) * 10000));
#endif

	tp->udata = udata;
	tp->owner = mod;
	tp->func = func;

	LIST_INSERT_HEAD(&timer_list, tp, link);

#ifdef USE_LIBBEGEMOT
	if ((tp->id = poll_start_timer(ticks * 10, 0, tfunc, tp)) < 0) {
		syslog(LOG_ERR, "cannot set timer: %m");
		exit(1);
	}
#else
	if (evSetTimer(evctx, tfunc, tp, due, evConsTime(0, 0), &tp->id)
	    == -1) {
		syslog(LOG_ERR, "cannot set timer: %m");
		exit(1);
	}
#endif
	return (tp);
}

/*
 * Start a repeatable timer. When used with USE_LIBBEGEMOT the first argument
 * is currently ignored and the initial number of ticks is set to the
 * repeat number of ticks.
 */
void *
timer_start_repeat(u_int ticks __unused, u_int repeat_ticks,
    void (*func)(void *), void *udata, struct lmodule *mod)
{
	struct timer *tp;
#ifndef USE_LIBBEGEMOT
	struct timespec due;
	struct timespec inter;
#endif

	if ((tp = malloc(sizeof(struct timer))) == NULL) {
		syslog(LOG_CRIT, "out of memory for timer");
		exit(1);
	}

#ifndef USE_LIBBEGEMOT
	due = evAddTime(evNowTime(),
	    evConsTime(ticks / 100, (ticks % 100) * 10000));
	inter = evConsTime(repeat_ticks / 100, (repeat_ticks % 100) * 10000);
#endif

	tp->udata = udata;
	tp->owner = mod;
	tp->func = func;

	LIST_INSERT_HEAD(&timer_list, tp, link);

#ifdef USE_LIBBEGEMOT
	if ((tp->id = poll_start_timer(repeat_ticks * 10, 1, trfunc, tp)) < 0) {
		syslog(LOG_ERR, "cannot set timer: %m");
		exit(1);
	}
#else
	if (evSetTimer(evctx, trfunc, tp, due, inter, &tp->id) == -1) {
		syslog(LOG_ERR, "cannot set timer: %m");
		exit(1);
	}
#endif
	return (tp);
}

/*
 * Stop a timer.
 */
void
timer_stop(void *p)
{
	struct timer *tp = p;

	LIST_REMOVE(tp, link);
#ifdef USE_LIBBEGEMOT
	poll_stop_timer(tp->id);
#else
	if (evClearTimer(evctx, tp->id) == -1) {
		syslog(LOG_ERR, "cannot stop timer: %m");
		exit(1);
	}
#endif
	free(p);
}

static void
timer_flush(struct lmodule *mod)
{
	struct timer *t, *t1;

	t = LIST_FIRST(&timer_list);
	while (t != NULL) {
		t1 = LIST_NEXT(t, link);
		if (t->owner == mod)
			timer_stop(t);
		t = t1;
	}
}

static void
snmp_printf_func(const char *fmt, ...)
{
	va_list ap;
	static char *pend = NULL;
	char *ret, *new;

	va_start(ap, fmt);
	vasprintf(&ret, fmt, ap);
	va_end(ap);

	if (ret == NULL)
		return;
	if (pend != NULL) {
		if ((new = realloc(pend, strlen(pend) + strlen(ret) + 1))
		    == NULL) {
			free(ret);
			return;
		}
		pend = new;
		strcat(pend, ret);
		free(ret);
	} else
		pend = ret;

	while ((ret = strchr(pend, '\n')) != NULL) {
		*ret = '\0';
		syslog(LOG_DEBUG, "%s", pend);
		if (strlen(ret + 1) == 0) {
			free(pend);
			pend = NULL;
			break;
		}
		strcpy(pend, ret + 1);
	}
}

static void
snmp_error_func(const char *err, ...)
{
	char errbuf[1000];
	va_list ap;

	if (!(snmp_trace & LOG_SNMP_ERRORS))
		return;

	va_start(ap, err);
	snprintf(errbuf, sizeof(errbuf), "SNMP: ");
	vsnprintf(errbuf + strlen(errbuf),
	    sizeof(errbuf) - strlen(errbuf), err, ap);
	va_end(ap);

	syslog(LOG_ERR, "%s", errbuf);
}

static void
snmp_debug_func(const char *err, ...)
{
	char errbuf[1000];
	va_list ap;

	va_start(ap, err);
	snprintf(errbuf, sizeof(errbuf), "SNMP: ");
	vsnprintf(errbuf+strlen(errbuf), sizeof(errbuf)-strlen(errbuf),
	    err, ap);
	va_end(ap);

	syslog(LOG_DEBUG, "%s", errbuf);
}

static void
asn_error_func(const struct asn_buf *b, const char *err, ...)
{
	char errbuf[1000];
	va_list ap;
	u_int i;

	if (!(snmp_trace & LOG_ASN1_ERRORS))
		return;

	va_start(ap, err);
	snprintf(errbuf, sizeof(errbuf), "ASN.1: ");
	vsnprintf(errbuf + strlen(errbuf),
	    sizeof(errbuf) - strlen(errbuf), err, ap);
	va_end(ap);

	if (b != NULL) {
		snprintf(errbuf + strlen(errbuf),
		    sizeof(errbuf) - strlen(errbuf), " at");
		for (i = 0; b->asn_len > i; i++)
			snprintf(errbuf + strlen(errbuf),
			    sizeof(errbuf) - strlen(errbuf),
			    " %02x", b->asn_cptr[i]);
	}

	syslog(LOG_ERR, "%s", errbuf);
}

/*
 * Create a new community
 */
u_int
comm_define(u_int priv, const char *descr, struct lmodule *owner,
    const char *str)
{
	struct community *c, *p;
	u_int ncomm;

	/* generate an identifier */
	do {
		if ((ncomm = next_community_index++) == UINT_MAX)
			next_community_index = 1;
		TAILQ_FOREACH(c, &community_list, link)
			if (c->value == ncomm)
				break;
	} while (c != NULL);

	if ((c = malloc(sizeof(struct community))) == NULL) {
		syslog(LOG_ERR, "comm_define: %m");
		return (0);
	}
	c->owner = owner;
	c->value = ncomm;
	c->descr = descr;
	c->string = NULL;
	c->private = priv;

	if (str != NULL) {
		if((c->string = malloc(strlen(str)+1)) == NULL) {
			free(c);
			return (0);
		}
		strcpy(c->string, str);
	}

	/* make index */
	if (c->owner == NULL) {
		c->index.len = 1;
		c->index.subs[0] = 0;
	} else {
		c->index = c->owner->index;
	}
	c->index.subs[c->index.len++] = c->private;

	/*
	 * Insert ordered
	 */
	TAILQ_FOREACH(p, &community_list, link) {
		if (asn_compare_oid(&p->index, &c->index) > 0) {
			TAILQ_INSERT_BEFORE(p, c, link);
			break;
		}
	}
	if (p == NULL)
		TAILQ_INSERT_TAIL(&community_list, c, link);
	return (c->value);
}

const char *
comm_string(u_int ncomm)
{
	struct community *p;

	TAILQ_FOREACH(p, &community_list, link)
		if (p->value == ncomm)
			return (p->string);
	return (NULL);
}

/*
 * Delete all communities allocated by a module
 */
static void
comm_flush(struct lmodule *mod)
{
	struct community *p, *p1;

	p = TAILQ_FIRST(&community_list);
	while (p != NULL) {
		p1 = TAILQ_NEXT(p, link);
		if (p->owner == mod) {
			free(p->string);
			TAILQ_REMOVE(&community_list, p, link);
			free(p);
		}
		p = p1;
	}
}

/*
 * Request ID handling.
 *
 * Allocate a new range of request ids. Use a first fit algorithm.
 */
u_int
reqid_allocate(int size, struct lmodule *mod)
{
	u_int type;
	struct idrange *r, *r1;

	if (size <= 0 || size > INT32_MAX) {
		syslog(LOG_CRIT, "%s: size out of range: %d", __func__, size);
		return (0);
	}
	/* allocate a type id */
	do {
		if ((type = next_idrange++) == UINT_MAX)
			next_idrange = 1;
		TAILQ_FOREACH(r, &idrange_list, link)
			if (r->type == type)
				break;
	} while(r != NULL);

	/* find a range */
	if (TAILQ_EMPTY(&idr…