add support for AgentX subagents in snmpd

snmp requests are now packaged into pseudo-continuations
to allow for being dispatched to seperate processes;
lightly tested for interoperability with NetSNMP, but
doesn't implement the complete set of AgentX messages

while here, clean up return types of mps_get* functions,
and make smi_insert refuse to insert duplicate OIDs

okay benno@ reyk@

1 files changed, 139 insertions, 0 deletions

diff --git a/usr.sbin/snmpd/util.c b/usr.sbin/snmpd/util.c
new file mode 100644
index 00000000000..e744be40a10
--- /dev/null
+++ b/usr.sbin/snmpd/util.c
@@ -0,0 +1,139 @@
+/*	$OpenBSD	*/
+/*
+ * Copyright (c) 2014 Bret Stephen Lambert <blambert@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/socket.h>
+
+#include <net/if.h>
+
+#include <event.h>
+
+#include "ber.h"
+#include "snmp.h"
+#include "snmpd.h"
+
+/*
+ * Convert variable bindings from AgentX to SNMP dialect.
+ */
+int
+varbind_convert(struct agentx_pdu *pdu, struct agentx_varbind_hdr *vbhdr,
+    struct ber_element **varbind, struct ber_element **iter)
+{
+	struct ber_oid			 oid;
+	u_int32_t			 d;
+	u_int64_t			 l;
+	int				 slen;
+	char				*str;
+	struct ber_element		*a;
+	int				 ret = AGENTX_ERR_NONE;
+
+	if (snmp_agentx_read_oid(pdu, (struct snmp_oid *)&oid) == -1) {
+		ret = AGENTX_ERR_PARSE_ERROR;
+		goto done;
+	}
+
+	*iter = ber_add_sequence(*iter);
+	if (*varbind == NULL)
+		*varbind = *iter;
+
+	a = ber_add_oid(*iter, &oid);
+
+	switch (vbhdr->type) {
+	case AGENTX_NO_SUCH_OBJECT:
+	case AGENTX_NO_SUCH_INSTANCE:
+	case AGENTX_END_OF_MIB_VIEW:
+	case AGENTX_NULL:
+		a = ber_add_null(a);
+		break;
+
+	case AGENTX_IP_ADDRESS:
+	case AGENTX_OPAQUE:
+	case AGENTX_OCTET_STRING:
+		str = snmp_agentx_read_octetstr(pdu, &slen);
+		if (str == NULL) {
+			ret = AGENTX_ERR_PARSE_ERROR;
+			goto done;
+		}
+		a = ber_add_nstring(a, str, slen);
+		break;
+
+	case AGENTX_OBJECT_IDENTIFIER:
+		if (snmp_agentx_read_oid(pdu,
+		    (struct snmp_oid *)&oid) == -1) {
+			ret = AGENTX_ERR_PARSE_ERROR;
+			goto done;
+		}
+		a = ber_add_oid(a, &oid);
+		break;
+
+	case AGENTX_INTEGER:
+	case AGENTX_COUNTER32:
+	case AGENTX_GAUGE32:
+	case AGENTX_TIME_TICKS:
+		if (snmp_agentx_read_int(pdu, &d) == -1) {
+			ret = AGENTX_ERR_PARSE_ERROR;
+			goto done;
+		}
+		a = ber_add_integer(a, d);
+		break;
+
+	case AGENTX_COUNTER64:
+		if (snmp_agentx_read_int64(pdu, &l) == -1) {
+			ret = AGENTX_ERR_PARSE_ERROR;
+			goto done;
+		}
+		a = ber_add_integer(a, l);
+		break;
+
+	default:
+		log_debug("unknown data type '%i'", vbhdr->type);
+		ret = AGENTX_ERR_PARSE_ERROR;
+		goto done;
+	}
+
+	/* AgentX types correspond to BER types */
+	switch (vbhdr->type) {
+	case BER_TYPE_INTEGER:
+	case BER_TYPE_BITSTRING:
+	case BER_TYPE_OCTETSTRING:
+	case BER_TYPE_NULL:
+	case BER_TYPE_OBJECT:
+		/* universal types */
+		break;
+
+	/* Convert AgentX error types to SNMP error types */
+	case AGENTX_NO_SUCH_OBJECT:
+		ber_set_header(a, BER_CLASS_CONTEXT, 0);
+		break;
+	case AGENTX_NO_SUCH_INSTANCE:
+		ber_set_header(a, BER_CLASS_CONTEXT, 1);
+		break;
+
+	case AGENTX_COUNTER64:
+		ber_set_header(a, BER_CLASS_APPLICATION, SNMP_COUNTER64);
+		break;
+
+	default:
+		/* application-specific types */
+		ber_set_header(a, BER_CLASS_APPLICATION, vbhdr->type);
+		break;
+	}
+ done:
+	return (ret);
+}