start working on an interface to send traps via snmpd.sock. userland

applications will be able to send imsgs defining the trap to snmpd and
the daemon will do the ASN.1/BER encoding before sending traps to the
registered receivers.  there are two advantages of this approach that
a) the applications do not need to handle any ASN.1/BER encoding and
b) snmpd will provide a central interface to define trap receivers.

discussed with thib and others

4 files changed, 217 insertions, 4 deletions

diff --git a/usr.sbin/snmpd/control.c b/usr.sbin/snmpd/control.c
index 24023e798c5..a048f652fa5 100644
--- a/usr.sbin/snmpd/control.c
+++ b/usr.sbin/snmpd/control.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.c,v 1.1 2007/12/05 09:22:44 reyk Exp $	*/
+/*	$OpenBSD: control.c,v 1.2 2008/01/16 09:36:30 reyk Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -230,6 +230,16 @@ control_dispatch_imsg(int fd, short event, void *arg)
 			}
 			c->flags |= CTL_CONN_NOTIFY;
 			break;
+		case IMSG_SNMP_TRAP:
+			if (snmpe_trap(&c->ibuf, imsg.hdr.pid) == -1) {
+				log_debug("control_dispatch_imsg: "
+				    "received invalid trap (pid %d)",
+				    imsg.hdr.pid);
+				imsg_free(&imsg);
+				control_close(fd);
+				return;
+			}
+			break;
 		default:
 			log_debug("control_dispatch_imsg: "
 			    "error handling imsg %d", imsg.hdr.type);
diff --git a/usr.sbin/snmpd/snmp.h b/usr.sbin/snmpd/snmp.h
index 0ba2d24d287..7d67cb44252 100644
--- a/usr.sbin/snmpd/snmp.h
+++ b/usr.sbin/snmpd/snmp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmp.h,v 1.2 2008/01/11 12:12:14 reyk Exp $	*/
+/*	$OpenBSD: snmp.h,v 1.3 2008/01/16 09:36:30 reyk Exp $	*/
 
 /*
  * Copyright (c) 2007 Reyk Floeter <reyk@vantronix.net>
@@ -19,6 +19,54 @@
 #ifndef SNMP_HEADER
 #define SNMP_HEADER
 
+/*
+ * SNMP IMSG interface
+ */
+
+#define SNMP_MAX_OID_LEN	128	/* max size of the OID _string_ */
+#define SNMP_SOCKET		"/var/run/snmpd.sock"
+
+enum snmp_type {
+	SNMP_IPADDR		= 0,
+	SNMP_COUNTER32		= 1,
+	SNMP_GAUGE32		= 2,
+	SNMP_UNSIGNED32		= 2,
+	SNMP_TIMETICKS		= 3,
+	SNMP_OPAQUE		= 4,
+	SNMP_NSAPADDR		= 5,
+	SNMP_COUNTER64		= 6,
+	SNMP_UINTEGER32		= 7,
+
+	SNMP_INTEGER32		= 100,
+	SNMP_BITSTRING		= 101,
+	SNMP_OCTETSTRING	= 102,
+	SNMP_NULL		= 103,
+	SNMP_OBJECT		= 104
+};
+
+enum snmp_imsg_ctl {
+	IMSG_SNMP_TRAP		= 1000,	/* something that works everywhere */
+	IMSG_SNMP_ELEMENT,
+	IMSG_SNMP_END
+};
+
+struct snmp_imsg_hdr {
+	u_int16_t	 imsg_type;
+	u_int16_t	 imsg_len;
+	u_int32_t	 imsg_peerid;
+	pid_t		 imsg_pid;
+};
+
+struct snmp_imsg {
+	char		 snmp_oid[SNMP_MAX_OID_LEN];
+	u_int8_t	 snmp_type;
+	u_int16_t	 snmp_len;
+};
+
+/*
+ * SNMP BER types
+ */
+
 enum snmp_version {
 	SNMP_V1			= 0,
 	SNMP_V2			= 1,
@@ -46,7 +94,9 @@ enum snmp_application {
 	SNMP_T_UNSIGNED32	= 2,
 	SNMP_T_TIMETICKS	= 3,
 	SNMP_T_OPAQUE		= 4,
+	SNMP_T_NSAPADDR		= 5,
 	SNMP_T_COUNTER64	= 6,
+	SNMP_T_UINTEGER32	= 7
 };
 
 enum snmp_generic_trap {
diff --git a/usr.sbin/snmpd/snmpd.h b/usr.sbin/snmpd/snmpd.h
index fc6418536b1..7499ea4231e 100644
--- a/usr.sbin/snmpd/snmpd.h
+++ b/usr.sbin/snmpd/snmpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpd.h,v 1.10 2008/01/03 15:03:47 reyk Exp $	*/
+/*	$OpenBSD: snmpd.h,v 1.11 2008/01/16 09:36:30 reyk Exp $	*/
 
 /*
  * Copyright (c) 2007 Reyk Floeter <reyk@vantronix.net>
@@ -387,6 +387,7 @@ struct kif_addr *kr_getnextaddr(struct in_addr *);
 
 /* snmpe.c */
 pid_t		 snmpe(struct snmpd *, int [2]);
+int		 snmpe_trap(struct imsgbuf *, pid_t);
 
 /* mps.c */
 struct ber_element *
diff --git a/usr.sbin/snmpd/snmpe.c b/usr.sbin/snmpd/snmpe.c
index 4db07333c10..44960a0abf7 100644
--- a/usr.sbin/snmpd/snmpe.c
+++ b/usr.sbin/snmpd/snmpe.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpe.c,v 1.10 2008/01/12 13:57:43 reyk Exp $	*/
+/*	$OpenBSD: snmpe.c,v 1.11 2008/01/16 09:36:30 reyk Exp $	*/
 
 /*
  * Copyright (c) 2007 Reyk Floeter <reyk@vantronix.net>
@@ -804,3 +804,155 @@ snmpe_recvmsg(int fd, short sig, void *arg)
 	if (resp != NULL)
 		ber_free_elements(resp);
 }
+
+int
+snmpe_trap(struct imsgbuf *ibuf, pid_t pid)
+{
+	struct imsg	 	 imsg;
+	int		 	 ret = -1, n, x = 0;
+	int		 	 done = 0;
+	struct snmp_imsg	*sm;
+	u_int32_t	 	 d;
+	u_int64_t	 	 l;
+	u_int8_t		*c;
+	char			 o[SNMP_MAX_OID_LEN];
+	struct ber_element	*ber, *trap = NULL, *oid = NULL, *a;
+	size_t			 len;
+
+	ber = trap = ber_add_sequence(NULL);
+
+	while (!done) {
+		while (!done) {
+			if ((n = imsg_get(ibuf, &imsg)) == -1)
+				goto done;
+			if (n == 0)
+				break;
+			switch (imsg.hdr.type) {
+			case IMSG_SNMP_ELEMENT:
+				if (imsg.hdr.len < (IMSG_HEADER_SIZE +
+				    sizeof(struct snmp_imsg)))
+					goto imsgdone;
+
+				sm = (struct snmp_imsg *)imsg.data;
+
+				if (oid == NULL) {
+					/* First element must be the trap OID */
+					if (sm->snmp_type != SNMP_NULL)
+						goto imsgdone;
+					ber = oid = ber_printf_elements(ber,
+					    "{o0}", sm->snmp_oid);
+					break;
+				}
+
+				ber = a = ber_add_sequence(ber);
+				a = ber_add_oidstring(a, sm->snmp_oid);
+
+				switch (sm->snmp_type) {
+				case SNMP_OBJECT:
+					if (sm->snmp_len != sizeof(o))
+						goto imsgdone;
+					bcopy(sm + 1, &o, sm->snmp_len);
+					a = ber_add_oidstring(a, o);
+					break;
+				case SNMP_BITSTRING:
+				case SNMP_OCTETSTRING:
+					if ((sm->snmp_len < 1) ||
+					    (sm->snmp_len >= SNMPD_MAXSTRLEN))
+						goto imsgdone;
+					if ((c =
+					    calloc(1, sm->snmp_len)) == NULL)
+						goto imsgdone;
+					bcopy(sm + 1, c, sm->snmp_len);
+					if (sm->snmp_type == SNMP_BITSTRING)
+						a = ber_add_bitstring(a, c,
+						    sm->snmp_len);
+					else
+						a = ber_add_nstring(a, c,
+						    sm->snmp_len);
+					a->be_free = 1;
+					break;
+				case SNMP_NULL:
+					a = ber_add_null(a);
+					break;
+				case SNMP_INTEGER32:
+				case SNMP_IPADDR:
+				case SNMP_COUNTER32:
+				case SNMP_GAUGE32:
+				case SNMP_TIMETICKS:
+				case SNMP_OPAQUE:
+				case SNMP_UINTEGER32:
+					if (sm->snmp_len != sizeof(d))
+						goto imsgdone;
+					bcopy(sm + 1, &d, sm->snmp_len);
+					a = ber_add_integer(a, d);
+					break;
+				case SNMP_COUNTER64:
+					if (sm->snmp_len != sizeof(l))
+						goto imsgdone;
+					bcopy(sm + 1, &l, sm->snmp_len);
+					a = ber_add_integer(a, d);
+					break;
+				default:
+					log_debug("snmpe_trap: illegal type %d",
+					    sm->snmp_type);
+					imsg_free(&imsg);
+					goto imsgdone;
+				}
+				switch (sm->snmp_type) {
+				case SNMP_INTEGER32:
+				case SNMP_BITSTRING:
+				case SNMP_OCTETSTRING:
+				case SNMP_NULL:
+				case SNMP_OBJECT:
+					/* universal types */
+					break;
+				case SNMP_IPADDR:
+				case SNMP_COUNTER32:
+				case SNMP_GAUGE32:
+				case SNMP_TIMETICKS:
+				case SNMP_OPAQUE:
+				case SNMP_NSAPADDR:
+				case SNMP_COUNTER64:
+				case SNMP_UINTEGER32:
+					/* application-specific types */
+					ber_set_header(a, BER_CLASS_APPLICATION,
+					    sm->snmp_type);
+					break;
+				}
+				x++;
+				break;
+			case IMSG_SNMP_END:
+				done = 1;
+				break;
+			default:
+				log_debug("snmpe_trap: illegal imsg %d",
+				    imsg.hdr.type);
+				goto imsgdone;
+			}
+			imsg_free(&imsg);
+		}
+		if (done)
+			break;
+		if ((n = imsg_read(ibuf)) == -1)
+			goto done;
+		if (n == 0)
+			goto done;
+	}
+
+	len = ber_calc_len(trap);
+	log_debug("snmpe_trap: %d bytes from pid %d", len, pid);
+
+	/* XXX send trap to registered receivers */
+
+#ifdef DEBUG
+	snmpe_debug_elements(trap);
+#endif
+
+	ret = 0;
+ imsgdone:
+	if (ret != 0)
+		imsg_free(&imsg);
+ done:
+	ber_free_elements(trap);
+	return (ret);
+}