1 /* $OpenBSD: trap.c,v 1.37 2021/09/02 05:41:02 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/types.h> 21 #include <sys/stat.h> 22 #include <sys/socket.h> 23 #include <sys/un.h> 24 #include <sys/tree.h> 25 26 #include <net/if.h> 27 #include <netinet/in.h> 28 #include <arpa/inet.h> 29 30 #include <stdlib.h> 31 #include <stdio.h> 32 #include <errno.h> 33 #include <event.h> 34 #include <fcntl.h> 35 #include <string.h> 36 #include <unistd.h> 37 #include <pwd.h> 38 39 #include "snmpd.h" 40 #include "mib.h" 41 42 void 43 trap_init(void) 44 { 45 struct ber_oid trapoid = OID(MIB_coldStart); 46 47 /* 48 * Send a coldStart to notify that the daemon has been 49 * started and re-initialized. 50 */ 51 trap_send(&trapoid, NULL); 52 } 53 54 int 55 trap_send(struct ber_oid *oid, struct ber_element *elm) 56 { 57 struct trap_address *tr; 58 struct ber_element *vblist, *trap; 59 struct ber_oid uptime = OID(MIB_sysUpTime); 60 struct ber_oid trapoid = OID(MIB_snmpTrapOID); 61 char ostr[SNMP_MAX_OID_STRLEN]; 62 struct oid oa, ob; 63 struct snmp_message *msg; 64 65 if (TAILQ_EMPTY(&snmpd_env->sc_trapreceivers)) 66 return (0); 67 68 smi_scalar_oidlen(&uptime); 69 smi_scalar_oidlen(&trapoid); 70 smi_scalar_oidlen(oid); 71 72 smi_oid2string(oid, ostr, sizeof(ostr), 0); 73 log_debug("trap_send: oid %s", ostr); 74 75 /* Setup OIDs to compare against the trap receiver MIB */ 76 bzero(&oa, sizeof(oa)); 77 bcopy(oid->bo_id, &oa.o_oid, sizeof(oa.o_oid)); 78 oa.o_oidlen = oid->bo_n; 79 bzero(&ob, sizeof(ob)); 80 ob.o_flags = OID_TABLE; 81 82 /* Add mandatory varbind elements */ 83 trap = ober_add_sequence(NULL); 84 vblist = ober_printf_elements(trap, "{Odt}{OO}", 85 &uptime, smi_getticks(), 86 BER_CLASS_APPLICATION, SNMP_T_TIMETICKS, 87 &trapoid, oid); 88 if (elm != NULL) 89 ober_link_elements(vblist, elm); 90 91 TAILQ_FOREACH(tr, &snmpd_env->sc_trapreceivers, entry) { 92 if (tr->ta_oid != NULL && tr->ta_oid->bo_n) { 93 /* The trap receiver may want only a specified MIB */ 94 bcopy(&tr->ta_oid->bo_id, &ob.o_oid, 95 sizeof(ob.o_oid)); 96 ob.o_oidlen = tr->ta_oid->bo_n; 97 if (smi_oid_cmp(&oa, &ob) != 0) 98 continue; 99 } 100 101 if ((msg = calloc(1, sizeof(*msg))) == NULL) 102 fatal("malloc"); 103 msg->sm_sock = snmpd_socket_af(&tr->ta_ss, SOCK_DGRAM); 104 if (msg->sm_sock == -1) { 105 log_warn("socket"); 106 free(msg); 107 continue; 108 } 109 memcpy(&(msg->sm_ss), &(tr->ta_ss), sizeof(msg->sm_ss)); 110 msg->sm_slen = tr->ta_ss.ss_len; 111 if (tr->ta_sslocal.ss_family != 0) { 112 memcpy(&(msg->sm_local_ss), &(tr->ta_sslocal), 113 sizeof(msg->sm_local_ss)); 114 msg->sm_local_slen = tr->ta_sslocal.ss_len; 115 } 116 msg->sm_version = tr->ta_version; 117 msg->sm_pdutype = SNMP_C_TRAPV2; 118 ober_set_application(&msg->sm_ber, smi_application); 119 msg->sm_request = arc4random(); 120 if ((msg->sm_varbindresp = ober_dup(trap->be_sub)) == NULL) 121 fatal("malloc"); 122 123 switch (msg->sm_version) { 124 case SNMP_V2: 125 (void)strlcpy(msg->sm_community, tr->ta_community, 126 sizeof(msg->sm_community)); 127 break; 128 case SNMP_V3: 129 msg->sm_msgid = msg->sm_request & INT32_MAX; 130 msg->sm_max_msg_size = READ_BUF_SIZE; 131 msg->sm_flags = tr->ta_seclevel != -1 ? 132 tr->ta_seclevel : snmpd_env->sc_min_seclevel; 133 msg->sm_secmodel = SNMP_SEC_USM; 134 msg->sm_engine_time = snmpd_engine_time(); 135 msg->sm_engine_boots = snmpd_env->sc_engine_boots; 136 memcpy(msg->sm_ctxengineid, snmpd_env->sc_engineid, 137 snmpd_env->sc_engineid_len); 138 msg->sm_ctxengineid_len = 139 snmpd_env->sc_engineid_len; 140 (void)strlcpy(msg->sm_username, tr->ta_usmusername, 141 sizeof(msg->sm_username)); 142 msg->sm_user = tr->ta_usmuser; 143 arc4random_buf(msg->sm_salt, sizeof(msg->sm_salt)); 144 break; 145 } 146 147 snmpe_response(msg); 148 } 149 ober_free_elements(trap); 150 151 return 0; 152 } 153