1/*	$OpenBSD: trap.c,v 1.43 2024/02/06 15:36:11 martijn Exp $	*/
2
3/*
4 * Copyright (c) 2008 Reyk Floeter <reyk@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/queue.h>
20#include <sys/socket.h>
21
22#include <ber.h>
23#include <stdint.h>
24#include <stdlib.h>
25#include <string.h>
26
27#include "log.h"
28#include "mib.h"
29#include "smi.h"
30#include "snmp.h"
31#include "snmpd.h"
32
33void
34trap_init(void)
35{
36	/*
37	 * Send a coldStart to notify that the daemon has been
38	 * started and re-initialized.
39	 */
40	trap_send(&OID(MIB_coldStart), NULL);
41}
42
43int
44trap_send(struct ber_oid *oid, struct ber_element *elm)
45{
46	struct trap_address	*tr;
47	struct ber_element	*vblist, *trap;
48	struct			 ber_oid uptime = OID(MIB_sysUpTime, 0);
49	struct			 ber_oid trapoid = OID(MIB_snmpTrapOID, 0);
50	char			 ostr[SNMP_MAX_OID_STRLEN];
51	struct snmp_message	*msg;
52	int			 r;
53
54	if (TAILQ_EMPTY(&snmpd_env->sc_trapreceivers))
55		return (0);
56
57	mib_oid2string(oid, ostr, sizeof(ostr), snmpd_env->sc_oidfmt);
58	log_debug("trap_send: oid %s", ostr);
59
60	/* Add mandatory varbind elements */
61	trap = ober_add_sequence(NULL);
62	vblist = ober_printf_elements(trap, "{Odt}{OO}",
63	    &uptime, smi_getticks(),
64	    BER_CLASS_APPLICATION, SNMP_T_TIMETICKS,
65	    &trapoid, oid);
66	if (elm != NULL)
67		ober_link_elements(vblist, elm);
68
69	TAILQ_FOREACH(tr, &snmpd_env->sc_trapreceivers, entry) {
70		if (tr->ta_oid.bo_n) {
71			/* The trap receiver may want only a specified MIB */
72			r = ober_oid_cmp(oid, &tr->ta_oid);
73			if (r != 0 && r != 2)
74				continue;
75		}
76
77		if ((msg = calloc(1, sizeof(*msg))) == NULL)
78			fatal("malloc");
79		msg->sm_sock = snmpd_socket_af(&tr->ta_ss, SOCK_DGRAM);
80		if (msg->sm_sock == -1) {
81			log_warn("socket");
82			free(msg);
83			continue;
84		}
85		memcpy(&(msg->sm_ss), &(tr->ta_ss), sizeof(msg->sm_ss));
86		msg->sm_slen = tr->ta_ss.ss_len;
87		if (tr->ta_sslocal.ss_family != 0) {
88			memcpy(&(msg->sm_local_ss), &(tr->ta_sslocal),
89			    sizeof(msg->sm_local_ss));
90			msg->sm_local_slen = tr->ta_sslocal.ss_len;
91		}
92		msg->sm_version = tr->ta_version;
93		msg->sm_pdutype = SNMP_C_TRAPV2;
94		ober_set_application(&msg->sm_ber, smi_application);
95		msg->sm_request = arc4random();
96		if ((msg->sm_varbindresp = ober_dup(trap->be_sub)) == NULL)
97			fatal("malloc");
98
99		switch (msg->sm_version) {
100		case SNMP_V2:
101			(void)strlcpy(msg->sm_community, tr->ta_community,
102			    sizeof(msg->sm_community));
103			break;
104		case SNMP_V3:
105			msg->sm_msgid = msg->sm_request & INT32_MAX;
106			msg->sm_max_msg_size = READ_BUF_SIZE;
107			msg->sm_flags = tr->ta_seclevel != -1 ?
108			    tr->ta_seclevel : snmpd_env->sc_min_seclevel;
109			msg->sm_secmodel = SNMP_SEC_USM;
110			msg->sm_engine_time = snmpd_engine_time();
111			msg->sm_engine_boots = snmpd_env->sc_engine_boots;
112			memcpy(msg->sm_ctxengineid, snmpd_env->sc_engineid,
113			    snmpd_env->sc_engineid_len);
114			msg->sm_ctxengineid_len =
115			    snmpd_env->sc_engineid_len;
116			(void)strlcpy(msg->sm_username, tr->ta_usmusername,
117			    sizeof(msg->sm_username));
118			msg->sm_user = tr->ta_usmuser;
119			arc4random_buf(msg->sm_salt, sizeof(msg->sm_salt));
120			break;
121		}
122
123		snmpe_response(msg);
124	}
125	ober_free_elements(trap);
126
127	return 0;
128}
129