1 /* $OpenBSD: trap.c,v 1.34 2019/12/09 16:51:10 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_agentx(struct agentx_handle *h, struct agentx_pdu *pdu, int *idx, 56 char **varcpy, int *vcpylen) 57 { 58 struct agentx_varbind_hdr vbhdr; 59 u_int32_t d; 60 struct ber_oid o, oid; 61 struct ber_oid uptime = OID(MIB_sysUpTime); 62 struct ber_oid trapoid = OID(MIB_snmpTrapOID); 63 struct ber_element *varbind, *iter; 64 int x = 0, state = 0; 65 int ret = AGENTX_ERR_NONE; 66 int seensysuptime, seentrapoid; 67 size_t len = 0; 68 char *v = NULL; 69 70 *varcpy = NULL; 71 varbind = NULL; 72 iter = NULL; 73 seensysuptime = seentrapoid = 0; 74 75 if (pdu->hdr->flags & AGENTX_NON_DEFAULT_CONTEXT) { 76 ret = AGENTX_ERR_UNSUPPORTED_CONTEXT; 77 goto done; 78 } 79 80 if ((v = malloc(pdu->hdr->length)) == NULL || 81 snmp_agentx_copy_raw(pdu, v, pdu->hdr->length) == -1) { 82 ret = AGENTX_ERR_PROCESSING_ERROR; 83 goto done; 84 } 85 86 smi_scalar_oidlen(&uptime); 87 smi_scalar_oidlen(&trapoid); 88 while (pdu->datalen > sizeof(struct agentx_hdr)) { 89 x++; 90 91 if (snmp_agentx_read_vbhdr(pdu, &vbhdr) == -1) { 92 ret = AGENTX_ERR_PARSE_ERROR; 93 goto done; 94 } 95 96 if (state < 2) { 97 if (snmp_agentx_read_oid(pdu, (struct snmp_oid *)&oid) == -1) { 98 ret = AGENTX_ERR_PARSE_ERROR; 99 goto done; 100 } 101 if (state == 0 && ober_oid_cmp(&oid, &uptime) == 0) { 102 if (snmp_agentx_read_int(pdu, &d) == -1) { 103 ret = AGENTX_ERR_PARSE_ERROR; 104 goto done; 105 } 106 state = 1; 107 continue; 108 } else if (ober_oid_cmp(&oid, &trapoid) == 0) { 109 if (snmp_agentx_read_oid(pdu, 110 (struct snmp_oid *)&o) == -1) { 111 ret = AGENTX_ERR_PARSE_ERROR; 112 goto done; 113 } 114 state = 2; 115 continue; 116 } else { 117 ret = AGENTX_ERR_PROCESSING_ERROR; 118 goto done; 119 } 120 } 121 122 ret = varbind_convert(pdu, &vbhdr, &varbind, &iter); 123 if (ret != AGENTX_ERR_NONE) 124 goto done; 125 } 126 127 if (varbind != NULL) 128 len = ober_calc_len(varbind); 129 log_debug("trap_agentx: from packetid %d len %zu elements %d", 130 pdu->hdr->packetid, len, x); 131 132 trap_send(&o, varbind); 133 134 *varcpy = v; 135 *vcpylen = pdu->hdr->length; 136 137 return (AGENTX_ERR_NONE); 138 done: 139 if (varbind != NULL) 140 ober_free_elements(varbind); 141 free(v); 142 *idx = x; 143 return (ret); 144 } 145 146 int 147 trap_send(struct ber_oid *oid, struct ber_element *elm) 148 { 149 int ret = 0, s; 150 struct address *tr; 151 struct ber_element *root, *b, *c, *trap; 152 struct ber ber; 153 char *cmn; 154 ssize_t len; 155 u_int8_t *ptr; 156 struct ber_oid uptime = OID(MIB_sysUpTime); 157 struct ber_oid trapoid = OID(MIB_snmpTrapOID); 158 char ostr[SNMP_MAX_OID_STRLEN]; 159 struct oid oa, ob; 160 161 if (TAILQ_EMPTY(&snmpd_env->sc_trapreceivers)) 162 return (0); 163 164 smi_scalar_oidlen(&uptime); 165 smi_scalar_oidlen(&trapoid); 166 smi_scalar_oidlen(oid); 167 168 smi_oid2string(oid, ostr, sizeof(ostr), 0); 169 log_debug("trap_send: oid %s", ostr); 170 171 /* Setup OIDs to compare against the trap receiver MIB */ 172 bzero(&oa, sizeof(oa)); 173 bcopy(oid->bo_id, &oa.o_oid, sizeof(oa.o_oid)); 174 oa.o_oidlen = oid->bo_n; 175 bzero(&ob, sizeof(ob)); 176 ob.o_flags = OID_TABLE; 177 178 /* Add mandatory varbind elements */ 179 trap = ober_add_sequence(NULL); 180 c = ober_printf_elements(trap, "{Odt}{OO}", 181 &uptime, smi_getticks(), 182 BER_CLASS_APPLICATION, SNMP_T_TIMETICKS, 183 &trapoid, oid); 184 if (elm != NULL) 185 ober_link_elements(c, elm); 186 187 bzero(&ber, sizeof(ber)); 188 189 TAILQ_FOREACH(tr, &snmpd_env->sc_trapreceivers, entry) { 190 if (tr->sa_oid != NULL && tr->sa_oid->bo_n) { 191 /* The trap receiver may want only a specified MIB */ 192 bcopy(&tr->sa_oid->bo_id, &ob.o_oid, 193 sizeof(ob.o_oid)); 194 ob.o_oidlen = tr->sa_oid->bo_n; 195 if (smi_oid_cmp(&oa, &ob) != 0) 196 continue; 197 } 198 199 if ((s = snmpd_socket_af(&tr->ss, htons(tr->port), 200 IPPROTO_UDP)) == -1) { 201 ret = -1; 202 goto done; 203 } 204 if (tr->sa_srcaddr != NULL) { 205 if (bind(s, (struct sockaddr *)&tr->sa_srcaddr->ss, 206 tr->sa_srcaddr->ss.ss_len) == -1) { 207 ret = -1; 208 goto done; 209 } 210 } 211 212 cmn = tr->sa_community != NULL ? 213 tr->sa_community : snmpd_env->sc_trcommunity; 214 215 /* SNMP header */ 216 root = ober_add_sequence(NULL); 217 b = ober_printf_elements(root, "ds{tddd", 218 SNMP_V2, cmn, BER_CLASS_CONTEXT, SNMP_C_TRAPV2, 219 arc4random(), 0, 0); 220 ober_link_elements(b, trap); 221 222 #ifdef DEBUG 223 smi_debug_elements(root); 224 #endif 225 len = ober_write_elements(&ber, root); 226 if (ober_get_writebuf(&ber, (void *)&ptr) > 0 && 227 sendto(s, ptr, len, 0, (struct sockaddr *)&tr->ss, 228 tr->ss.ss_len) != -1) { 229 snmpd_env->sc_stats.snmp_outpkts++; 230 ret++; 231 } 232 233 close(s); 234 ober_unlink_elements(b); 235 ober_free_elements(root); 236 } 237 238 done: 239 ober_free_elements(trap); 240 ober_free(&ber); 241 242 return (ret); 243 } 244