Introduce application_internal.c. This backend is meant to replace

application_legacy.c, mps.c, and mib.c. This commit just introduces the
backend. The existing MIBs inside mib.c will be copied over in
subsequent commits.

OK tb@

5 files changed, 284 insertions, 6 deletions

diff --git a/usr.sbin/snmpd/Makefile b/usr.sbin/snmpd/Makefile
index 261e89b62c2..26f2ff8aeb6 100644
--- a/usr.sbin/snmpd/Makefile
+++ b/usr.sbin/snmpd/Makefile
@@ -1,9 +1,9 @@
-#	$OpenBSD: Makefile,v 1.22 2022/10/25 10:46:59 martijn Exp $
+#	$OpenBSD: Makefile,v 1.23 2023/11/04 09:22:52 martijn Exp $
 
 PROG=		snmpd
 MAN=		snmpd.8 snmpd.conf.5
 SRCS=		parse.y log.c snmpe.c application.c application_legacy.c \
-		    application_blocklist.c \
+		    application_blocklist.c application_internal.c \
 		    application_agentx.c ax.c \
 		    mps.c trap.c mib.c smi.c snmpd.c \
 		    proc.c usm.c traphandler.c util.c
diff --git a/usr.sbin/snmpd/application.c b/usr.sbin/snmpd/application.c
index c36f059345f..2663c9ed55e 100644
--- a/usr.sbin/snmpd/application.c
+++ b/usr.sbin/snmpd/application.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: application.c,v 1.27 2023/10/29 11:20:06 martijn Exp $	*/
+/*	$OpenBSD: application.c,v 1.28 2023/11/04 09:22:52 martijn Exp $	*/
 
 /*
  * Copyright (c) 2021 Martijn van Duren <martijn@openbsd.org>
@@ -159,6 +159,7 @@ void
 appl_init(void)
 {
 	appl_blocklist_init();
+	appl_internal_init();
 	appl_legacy_init();
 	appl_agentx_init();
 }
@@ -169,6 +170,7 @@ appl_shutdown(void)
 	struct appl_context *ctx, *tctx;
 
 	appl_blocklist_shutdown();
+	appl_internal_shutdown();
 	appl_legacy_shutdown();
 	appl_agentx_shutdown();
 
diff --git a/usr.sbin/snmpd/application.h b/usr.sbin/snmpd/application.h
index 39e7b5fc410..6e638e2c988 100644
--- a/usr.sbin/snmpd/application.h
+++ b/usr.sbin/snmpd/application.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: application.h,v 1.6 2023/10/24 13:28:11 martijn Exp $	*/
+/*	$OpenBSD: application.h,v 1.7 2023/11/04 09:22:52 martijn Exp $	*/
 
 /*
  * Copyright (c) 2021 Martijn van Duren <martijn@openbsd.org>
@@ -147,3 +147,7 @@ void	 appl_agentx_backend(int);
 /* application_blocklist.c */
 void	 appl_blocklist_init(void);
 void	 appl_blocklist_shutdown(void);
+
+/* application_internal.c */
+void	 appl_internal_init(void);
+void	 appl_internal_shutdown(void);
diff --git a/usr.sbin/snmpd/application_internal.c b/usr.sbin/snmpd/application_internal.c
new file mode 100644
index 00000000000..5d2cdb1edb1
--- /dev/null
+++ b/usr.sbin/snmpd/application_internal.c
@@ -0,0 +1,271 @@
+/*	$OpenBSD: application_internal.c,v 1.1 2023/11/04 09:22:52 martijn Exp $	*/
+
+/*
+ * Copyright (c) 2023 Martijn van Duren <martijn@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/tree.h>
+
+#include <event.h>
+#include <stdlib.h>
+
+#include "application.h"
+#include "log.h"
+#include "mib.h"
+#include "smi.h"
+#include "snmpd.h"
+
+struct appl_internal_object {
+	struct ber_oid			 oid;
+	struct ber_element *		(*get)(struct ber_oid *);
+	/* No getnext means the object is scalar */
+	struct ber_element *		(*getnext)(int8_t, struct ber_oid *);
+
+	RB_ENTRY(appl_internal_object)	 entry;
+};
+
+void appl_internal_region(struct ber_oid *);
+void appl_internal_object(struct ber_oid *,
+    struct ber_element *(*)(struct ber_oid *),
+    struct ber_element *(*)(int8_t, struct ber_oid *));
+void appl_internal_get(struct appl_backend *, int32_t, int32_t, const char *,
+    struct appl_varbind *);
+void appl_internal_getnext(struct appl_backend *, int32_t, int32_t,
+    const char *, struct appl_varbind *);
+struct appl_internal_object *appl_internal_object_parent(struct ber_oid *);
+int appl_internal_object_cmp(struct appl_internal_object *,
+    struct appl_internal_object *);
+
+struct appl_backend_functions appl_internal_functions = {
+	.ab_get = appl_internal_get,
+	.ab_getnext = appl_internal_getnext,
+	.ab_getbulk = NULL, /* getbulk is too complex */
+};
+
+struct appl_backend appl_internal = {
+	.ab_name = "internal",
+	.ab_cookie = NULL,
+	.ab_retries = 0,
+	.ab_range = 1,
+	.ab_fn = &appl_internal_functions
+};
+
+static RB_HEAD(appl_internal_objects, appl_internal_object)
+    appl_internal_objects = RB_INITIALIZER(&appl_internal_objects);
+RB_PROTOTYPE_STATIC(appl_internal_objects, appl_internal_object, entry,
+    appl_internal_object_cmp);
+
+void
+appl_internal_init(void)
+{
+}
+
+void
+appl_internal_shutdown(void)
+{
+	struct appl_internal_object *object;
+
+	while ((object = RB_ROOT(&appl_internal_objects)) != NULL) {
+		RB_REMOVE(appl_internal_objects, &appl_internal_objects,
+		    object);
+		free(object);
+	}
+
+	appl_close(&appl_internal);
+}
+
+void
+appl_internal_region(struct ber_oid *oid)
+{
+	enum appl_error error;
+	char oidbuf[1024];
+
+	error = appl_register(NULL, 150, 1, oid, 0, 1, 0, 0, &appl_internal);
+	/*
+	 * Ignore requestDenied, duplicateRegistration, and unsupportedContext
+	 */
+	if (error == APPL_ERROR_PROCESSINGERROR ||
+	    error == APPL_ERROR_PARSEERROR) {
+		smi_oid2string(oid, oidbuf, sizeof(oidbuf), 0);
+		fatalx("internal: Failed to register %s", oidbuf);
+	}
+}
+
+void
+appl_internal_object(struct ber_oid *oid,
+    struct ber_element *(*get)(struct ber_oid *),
+    struct ber_element *(*getnext)(int8_t, struct ber_oid *))
+{
+	struct appl_internal_object *obj;
+
+	if ((obj = calloc(1, sizeof(*obj))) == NULL)
+		fatal(NULL);
+	obj->oid = *oid;
+	obj->get = get;
+	obj->getnext = getnext;
+
+	RB_INSERT(appl_internal_objects, &appl_internal_objects, obj);
+}
+
+void
+appl_internal_get(struct appl_backend *backend, __unused int32_t transactionid,
+    int32_t requestid, __unused const char *ctx, struct appl_varbind *vblist)
+{
+	struct ber_oid oid;
+	struct appl_internal_object *object;
+	struct appl_varbind *vb, *resp;
+	size_t i;
+	int r;
+
+	for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++)
+		continue;
+
+	if ((resp = calloc(i, sizeof(*resp))) == NULL) {
+		log_warn("%s", backend->ab_name);
+		appl_response(backend, requestid, APPL_ERROR_GENERR, 1, vblist);
+		return;
+	}
+
+	for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++) {
+		resp[i].av_oid = vb->av_oid;
+		if ((object = appl_internal_object_parent(&vb->av_oid)) == NULL)
+			resp[i].av_value =
+			    appl_exception(APPL_EXC_NOSUCHOBJECT);
+		else {
+			oid = object->oid;
+			/* Add 0 element for scalar */
+			if (object->getnext == NULL)
+				oid.bo_id[oid.bo_n++] = 0;
+			r = ober_oid_cmp(&vb->av_oid, &oid);
+			if ((r == 0 && object->getnext == NULL) ||
+			    (r == 2 && object->getnext != NULL))
+				resp[i].av_value = object->get(&resp[i].av_oid);
+			else
+				resp[i].av_value =
+				    appl_exception(APPL_EXC_NOSUCHINSTANCE);
+		}
+		if (resp[i].av_value == NULL) {
+			log_warnx("%s: Failed to get value", backend->ab_name);
+			goto fail;
+		}
+		resp[i].av_next = &resp[i + 1];
+	}
+	resp[i - 1].av_next = NULL;
+
+	appl_response(backend, requestid, APPL_ERROR_NOERROR, 0, resp);
+	return;
+
+ fail:
+	for (vb = resp; vb != NULL; vb = vb->av_next)
+		ober_free_elements(vb->av_value);
+	free(resp);
+	appl_response(backend, requestid, APPL_ERROR_GENERR, i + 1, vblist);
+}
+
+void
+appl_internal_getnext(struct appl_backend *backend,
+    __unused int32_t transactionid, int32_t requestid, __unused const char *ctx,
+    struct appl_varbind *vblist)
+{
+	struct ber_oid oid;
+	struct appl_internal_object *object, search;
+	struct appl_varbind *vb, *resp;
+	size_t i;
+	int r;
+	int8_t include;
+
+	for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++)
+		continue;
+
+	if ((resp = calloc(i, sizeof(*resp))) == NULL) {
+		log_warn("%s", backend->ab_name);
+		appl_response(backend, requestid, APPL_ERROR_GENERR, 1, vblist);
+		return;
+	}
+
+	for (i = 0, vb = vblist; vb != NULL; vb = vb->av_next, i++) {
+		resp[i].av_oid = vb->av_oid;
+		object = appl_internal_object_parent(&vb->av_oid);
+		if (object == NULL) {
+			search.oid = vb->av_oid;
+			object = RB_NFIND(appl_internal_objects,
+			    &appl_internal_objects, &search);
+		}
+
+		include = vb->av_include;
+		for (; object != NULL; object = RB_NEXT(appl_internal_objects,
+		    &appl_internal_objects, object), include = 1) {
+			if (object->getnext == NULL) {
+				oid = object->oid;
+				oid.bo_id[oid.bo_n++] = 0;
+				r = ober_oid_cmp(&resp[i].av_oid, &oid);
+				if (r > 0 || (r == 0 && !include))
+					continue;
+				resp[i].av_oid = oid;
+				resp[i].av_value = object->get(&oid);
+				break;
+			}
+			/* non-scalar */
+			fatalx("%s: not implemented", backend->ab_name);
+		}
+		if (ober_oid_cmp(&resp[i].av_oid, &vb->av_oid_end) >= 0 ||
+		    object == NULL) {
+			resp[i].av_oid = vb->av_oid;
+			ober_free_elements(resp[i].av_value);
+			resp[i].av_value =
+			    appl_exception(APPL_EXC_ENDOFMIBVIEW);
+		}
+		if (resp[i].av_value == NULL) {
+			log_warnx("%s: Failed to get value", backend->ab_name);
+			goto fail;
+		}
+		resp[i].av_next = &resp[i + 1];
+	}
+	resp[i - 1].av_next = NULL;
+
+	appl_response(backend, requestid, APPL_ERROR_NOERROR, 0, resp);
+	return;
+
+ fail:
+	for (vb = resp; vb != NULL; vb = vb->av_next)
+		ober_free_elements(vb->av_value);
+	free(resp);
+	appl_response(backend, requestid, APPL_ERROR_GENERR, i + 1, vblist);
+}
+
+struct appl_internal_object *
+appl_internal_object_parent(struct ber_oid *oid)
+{
+	struct appl_internal_object *object, search;
+
+	search.oid = *oid;
+	do {
+		if ((object = RB_FIND(appl_internal_objects,
+		    &appl_internal_objects, &search)) != NULL)
+			return object;
+	} while (--search.oid.bo_n > 0);
+
+	return NULL;
+}
+
+int
+appl_internal_object_cmp(struct appl_internal_object *o1,
+    struct appl_internal_object *o2)
+{
+	return ober_oid_cmp(&o1->oid, &o2->oid);
+}
+
+RB_GENERATE_STATIC(appl_internal_objects, appl_internal_object, entry,
+    appl_internal_object_cmp);
diff --git a/usr.sbin/snmpd/snmpd.h b/usr.sbin/snmpd/snmpd.h
index 7abeeea0adf..3c46a451b1e 100644
--- a/usr.sbin/snmpd/snmpd.h
+++ b/usr.sbin/snmpd/snmpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: snmpd.h,v 1.106 2022/10/06 14:41:08 martijn Exp $	*/
+/*	$OpenBSD: snmpd.h,v 1.107 2023/11/04 09:22:52 martijn Exp $	*/
 
 /*
  * Copyright (c) 2007, 2008, 2012 Reyk Floeter <reyk@openbsd.org>
@@ -215,7 +215,8 @@ struct oid {
 	(((_oid)->o_flags & OID_IFSET) &&				\
 	((_oid)->o_data == NULL) && ((_oid)->o_val == 0))
 
-#define OID(...)		{ { __VA_ARGS__ } }
+#define OID(...)		(struct ber_oid){ { __VA_ARGS__ },	\
+    (sizeof((uint32_t []) { __VA_ARGS__ }) / sizeof(uint32_t)) }
 #define MIBDECL(...)		{ { MIB_##__VA_ARGS__ } }, #__VA_ARGS__
 #define MIB(...)		{ { MIB_##__VA_ARGS__ } }, NULL
 #define MIBEND			{ { 0 } }, NULL