SNMP agent rewrite

- SNMPv2c support - Greatly reduced RAM usage, no memory pools any more - API cleanup - MIB2 is separated from SNMP stack - Support for multiple MIBs (snmp_set_mibs call) - e.g. for private MIB - Improved MIB2 implementation (tcpConnTable etc.) - Redesigned simple and generic API for MIB implementation - Comfortable node types for scalar arrays and tables - Counter64, bit and truthvalue datatype support - Callbacks for SNMP writes - Runs on two APIs: RAW and netconn - Async API is gone - the stack now supports netconn API instead, so blocking operations can be done in MIB calls. SNMP runs in a worker thread when netconn API is used. - Simplified thread sync support for MIBs - useful when MIBs need to access variables shared with other threads without locking (used in MIB2 to access lwIP stats from lwIP thread) Currently in work: - Traps rewrite - MIB compiler
2026-08-10 01:23:48 +08:00 · 2015-12-26 11:43:29 +01:00
parent 0178d1d2ee
commit 7b946fa9b1
32 changed files with 8034 additions and 8176 deletions
--- a/src/include/lwip/apps/snmp.h
+++ b/src/include/lwip/apps/snmp.h
@@ -28,6 +28,7 @@
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Leon Woestenberg <leon.woestenberg@axon.tv>
+ *         Martin Hentschel <info@cl-soft.de>
 *
 */
 #ifndef LWIP_HDR_APPS_SNMP_H
@@ -41,55 +42,60 @@ extern "C" {

 #if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */

-#include "lwip/ip.h"
-    
-/** fixed maximum length for object identifier type */
-#define LWIP_SNMP_OBJ_ID_LEN 32
-
-/** internal object identifier representation */
-struct snmp_obj_id
-{
-  u8_t len;
-  s32_t id[LWIP_SNMP_OBJ_ID_LEN];
-};
+#include "lwip/err.h"
+#include "lwip/apps/snmp_core.h"

 /** Agent setup, start listening to port 161. */
 void snmp_init(void);
+void snmp_set_mibs(const struct snmp_mib **mibs, u8_t num_mibs);
+
+/**
+* 'device enterprise oid' is used for 'device OID' field in trap PDU's (for identification of generating device)
+* as well as for value returned by MIB-2 'sysObjectID' field (if internal MIB2 implementation is used).
+* The 'device enterprise oid' shall point to an OID located under 'private-enterprises' branch (1.3.6.1.4.1.XXX). If a vendor
+* wants to provide a custom object there, he has to get its own enterprise oid from IANA (http://www.iana.org). It
+* is not allowed to use LWIP enterprise ID!
+* In order to identify a specific device it is recommended to create a dedicated OID for each device type under its own 
+* enterprise oid.
+* e.g.
+* device a > 1.3.6.1.4.1.XXX(ent-oid).1(devices).1(device a)
+* device b > 1.3.6.1.4.1.XXX(ent-oid).1(devices).2(device b)
+* for more details see description of 'sysObjectID' field in RFC1213-MIB
+*/
+void snmp_set_device_enterprise_oid(const struct snmp_obj_id* device_enterprise_oid);
+const struct snmp_obj_id* snmp_get_device_enterprise_oid(void);
+
 void snmp_trap_dst_enable(u8_t dst_idx, u8_t enable);
 void snmp_trap_dst_ip_set(u8_t dst_idx, const ip_addr_t *dst);

+#define SNMP_GENTRAP_COLDSTART 0
+#define SNMP_GENTRAP_WARMSTART 1
+#define SNMP_GENTRAP_LINKDOWN 2
+#define SNMP_GENTRAP_LINKUP 3
+#define SNMP_GENTRAP_AUTH_FAILURE 4
+#define SNMP_GENTRAP_EGP_NEIGHBOR_LOSS 5
+#define SNMP_GENTRAP_ENTERPRISE_SPECIFIC 6
+err_t snmp_send_trap_generic(s32_t generic_trap);
+err_t snmp_send_trap_specific(s32_t specific_trap);
+
+#define SNMP_AUTH_TRAPS_DISABLED 0
+#define SNMP_AUTH_TRAPS_ENABLED  1
+void snmp_set_auth_traps_enabled(u8_t enable);
+u8_t snmp_get_auth_traps_enabled(void);
+
 const char * snmp_get_community(void);
-void snmp_set_community(const char * const community);
-#if SNMP_COMMUNITY_EXT
 const char * snmp_get_community_write(void);
 const char * snmp_get_community_trap(void);
+void snmp_set_community(const char * const community);
 void snmp_set_community_write(const char * const community);
 void snmp_set_community_trap(const char * const community);
-#endif /* SNMP_COMMUNITY_EXT */

-/* system */
-void snmp_set_sysdescr(const u8_t* str, const u8_t* len);
-void snmp_set_sysobjid(const struct snmp_obj_id *oid);
-void snmp_get_sysobjid_ptr(const struct snmp_obj_id **oid);
-void snmp_set_syscontact(u8_t *ocstr, u8_t *ocstrlen, u8_t bufsize);
-void snmp_set_sysname(u8_t *ocstr, u8_t *ocstrlen, u8_t bufsize);
-void snmp_set_syslocation(u8_t *ocstr, u8_t *ocstrlen, u8_t bufsize);
-void snmp_set_snmpenableauthentraps(u8_t *value);
-void snmp_msg_event(u8_t request_id);
 void snmp_coldstart_trap(void);
 void snmp_authfail_trap(void);
-#else
-/* LWIP_SNMP support not available */
-/* define everything to be empty */

-/* system */
-#define snmp_set_sysdescr(str, len)
-#define snmp_set_sysobjid(oid)
-#define snmp_get_sysobjid_ptr(oid)
-#define snmp_set_syscontact(ocstr, ocstrlen, bufsize)
-#define snmp_set_sysname(ocstr, ocstrlen, bufsize)
-#define snmp_set_syslocation(ocstr, ocstrlen, bufsize)
-#define snmp_set_snmpenableauthentraps(value)
+typedef void (*snmp_write_callback_fct)(const u32_t* oid, u8_t oid_len, void* callback_arg);
+void snmp_set_write_callback(snmp_write_callback_fct write_callback, void* callback_arg);
+
 #endif /* LWIP_SNMP */

 #ifdef __cplusplus
--- a/src/include/lwip/apps/snmp_asn1.h
+++ b/src/include/lwip/apps/snmp_asn1.h
@@ -1,105 +0,0 @@
-/**
- * @file
- * Abstract Syntax Notation One (ISO 8824, 8825) codec.
- */
-
-/*
- * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- * 3. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
- * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
- * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
- * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
- * OF SUCH DAMAGE.
- *
- * Author: Christiaan Simons <christiaan.simons@axon.tv>
- */
-
-#ifndef LWIP_HDR_APPS_SNMP_ASN1_H
-#define LWIP_HDR_APPS_SNMP_ASN1_H
-
-#include "lwip/apps/snmp_opts.h"
-#include "lwip/err.h"
-#include "lwip/pbuf.h"
-#include "lwip/apps/snmp.h"
-
-#if LWIP_SNMP
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#define SNMP_ASN1_UNIV   (0)    /* (!0x80 | !0x40) */
-#define SNMP_ASN1_APPLIC (0x40) /* (!0x80 |  0x40) */
-#define SNMP_ASN1_CONTXT (0x80) /* ( 0x80 | !0x40) */
-
-#define SNMP_ASN1_CONSTR (0x20) /* ( 0x20) */
-#define SNMP_ASN1_PRIMIT (0)    /* (!0x20) */
-
-/* universal tags (from ASN.1 spec.) */
-#define SNMP_ASN1_INTEG  2
-#define SNMP_ASN1_OC_STR 4
-#define SNMP_ASN1_NUL    5
-#define SNMP_ASN1_OBJ_ID 6
-#define SNMP_ASN1_SEQ    16
-
-/* application specific (SNMP) tags (from SNMPv2-SMI) */
-#define SNMP_ASN1_IPADDR    0  /* [APPLICATION 0] IMPLICIT OCTET STRING (SIZE (4)) */
-#define SNMP_ASN1_COUNTER   1  /* [APPLICATION 1] IMPLICIT INTEGER (0..4294967295) => u32_t */
-#define SNMP_ASN1_GAUGE     2  /* [APPLICATION 2] IMPLICIT INTEGER (0..4294967295) => u32_t */
-#define SNMP_ASN1_TIMETICKS 3  /* [APPLICATION 3] IMPLICIT INTEGER (0..4294967295) => u32_t */
-#define SNMP_ASN1_OPAQUE    4  /* [APPLICATION 4] IMPLICIT OCTET STRING */
-#define SNMP_ASN1_COUNTER64 6  /* [APPLICATION 6] IMPLICIT INTEGER (0..18446744073709551615) */
-
-/* context specific (SNMP) tags (from SNMP spec. RFC1157) */
-#define SNMP_ASN1_PDU_GET_REQ      0
-#define SNMP_ASN1_PDU_GET_NEXT_REQ 1
-#define SNMP_ASN1_PDU_GET_RESP     2
-#define SNMP_ASN1_PDU_SET_REQ      3
-#define SNMP_ASN1_PDU_TRAP         4
-
-err_t snmp_asn1_dec_type(struct pbuf *p, u16_t ofs, u8_t *type);
-err_t snmp_asn1_dec_length(struct pbuf *p, u16_t ofs, u8_t *octets_used, u16_t *length);
-err_t snmp_asn1_dec_u32t(struct pbuf *p, u16_t ofs, u16_t len, u32_t *value);
-err_t snmp_asn1_dec_s32t(struct pbuf *p, u16_t ofs, u16_t len, s32_t *value);
-err_t snmp_asn1_dec_oid(struct pbuf *p, u16_t ofs, u16_t len, struct snmp_obj_id *oid);
-err_t snmp_asn1_dec_raw(struct pbuf *p, u16_t ofs, u16_t len, u16_t raw_len, u8_t *raw);
-
-void snmp_asn1_enc_length_cnt(u16_t length, u8_t *octets_needed);
-void snmp_asn1_enc_u32t_cnt(u32_t value, u16_t *octets_needed);
-void snmp_asn1_enc_s32t_cnt(s32_t value, u16_t *octets_needed);
-void snmp_asn1_enc_oid_cnt(u16_t ident_len, const s32_t *ident, u16_t *octets_needed);
-err_t snmp_asn1_enc_type(struct pbuf *p, u16_t ofs, u8_t type);
-err_t snmp_asn1_enc_length(struct pbuf *p, u16_t ofs, u16_t length);
-err_t snmp_asn1_enc_u32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, u32_t value);
-err_t snmp_asn1_enc_s32t(struct pbuf *p, u16_t ofs, u16_t octets_needed, s32_t value);
-err_t snmp_asn1_enc_oid(struct pbuf *p, u16_t ofs, u16_t ident_len, const s32_t *ident);
-err_t snmp_asn1_enc_raw(struct pbuf *p, u16_t ofs, u16_t raw_len, const u8_t *raw);
-
-err_t snmp_asn1_dec_bits(const u8_t *buf, u32_t buf_len, u32_t *bit_value);
-u8_t  snmp_asn1_enc_bits(u8_t *buf, u32_t buf_len, u32_t bit_value);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* LWIP_SNMP */
-
-#endif /* LWIP_HDR_APPS_SNMP_ASN1_H */
--- a/src/include/lwip/apps/snmp_core.h
+++ b/src/include/lwip/apps/snmp_core.h
@@ -0,0 +1,349 @@
+/**
+ * @file
+ * Generic MIB tree structures.
+ *
+ * @todo namespace prefixes
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ *         Martin Hentschel <info@cl-soft.de>
+ */
+
+#ifndef LWIP_HDR_APPS_SNMP_CORE_H
+#define LWIP_HDR_APPS_SNMP_CORE_H
+
+#include "lwip/apps/snmp_opts.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/ip_addr.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* basic ASN1 defines */
+#define SNMP_ASN1_CLASS_UNIVERSAL   0x00
+#define SNMP_ASN1_CLASS_APPLICATION 0x40
+#define SNMP_ASN1_CLASS_CONTEXT     0x80
+#define SNMP_ASN1_CLASS_PRIVATE     0xC0
+
+#define SNMP_ASN1_CONTENTTYPE_PRIMITIVE   0x00
+#define SNMP_ASN1_CONTENTTYPE_CONSTRUCTED 0x20
+
+/* universal tags (from ASN.1 spec.) */
+#define SNMP_ASN1_UNIVERSAL_END_OF_CONTENT  0
+#define SNMP_ASN1_UNIVERSAL_INTEGER         2
+#define SNMP_ASN1_UNIVERSAL_OCTET_STRING    4
+#define SNMP_ASN1_UNIVERSAL_NULL            5
+#define SNMP_ASN1_UNIVERSAL_OBJECT_ID       6
+#define SNMP_ASN1_UNIVERSAL_SEQUENCE_OF    16
+
+/* application specific (SNMP) tags (from SNMPv2-SMI) */
+#define SNMP_ASN1_APPLICATION_IPADDR    0  /* [APPLICATION 0] IMPLICIT OCTET STRING (SIZE (4)) */
+#define SNMP_ASN1_APPLICATION_COUNTER   1  /* [APPLICATION 1] IMPLICIT INTEGER (0..4294967295) => u32_t */
+#define SNMP_ASN1_APPLICATION_GAUGE     2  /* [APPLICATION 2] IMPLICIT INTEGER (0..4294967295) => u32_t */
+#define SNMP_ASN1_APPLICATION_TIMETICKS 3  /* [APPLICATION 3] IMPLICIT INTEGER (0..4294967295) => u32_t */
+#define SNMP_ASN1_APPLICATION_OPAQUE    4  /* [APPLICATION 4] IMPLICIT OCTET STRING */
+#define SNMP_ASN1_APPLICATION_COUNTER64 6  /* [APPLICATION 6] IMPLICIT INTEGER (0..18446744073709551615) */
+
+/* context specific (SNMP) tags (from RFC 1905) */
+#define SNMP_ASN1_CONTEXT_VARBIND_NO_SUCH_INSTANCE 1
+
+/* full ASN1 type defines */
+#define SNMP_ASN1_TYPE_END_OF_CONTENT (SNMP_ASN1_CLASS_UNIVERSAL | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_UNIVERSAL_END_OF_CONTENT)
+#define SNMP_ASN1_TYPE_INTEGER        (SNMP_ASN1_CLASS_UNIVERSAL | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_UNIVERSAL_INTEGER)
+#define SNMP_ASN1_TYPE_OCTET_STRING   (SNMP_ASN1_CLASS_UNIVERSAL | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_UNIVERSAL_OCTET_STRING)
+#define SNMP_ASN1_TYPE_NULL           (SNMP_ASN1_CLASS_UNIVERSAL | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_UNIVERSAL_NULL)
+#define SNMP_ASN1_TYPE_OBJECT_ID      (SNMP_ASN1_CLASS_UNIVERSAL | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_UNIVERSAL_OBJECT_ID)
+#define SNMP_ASN1_TYPE_SEQUENCE       (SNMP_ASN1_CLASS_UNIVERSAL | SNMP_ASN1_CONTENTTYPE_CONSTRUCTED | SNMP_ASN1_UNIVERSAL_SEQUENCE_OF)
+#define SNMP_ASN1_TYPE_IPADDR         (SNMP_ASN1_CLASS_APPLICATION | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_APPLICATION_IPADDR)
+#define SNMP_ASN1_TYPE_COUNTER        (SNMP_ASN1_CLASS_APPLICATION | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_APPLICATION_COUNTER)
+#define SNMP_ASN1_TYPE_GAUGE          (SNMP_ASN1_CLASS_APPLICATION | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_APPLICATION_GAUGE)
+#define SNMP_ASN1_TYPE_TIMETICKS      (SNMP_ASN1_CLASS_APPLICATION | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_APPLICATION_TIMETICKS)
+#define SNMP_ASN1_TYPE_OPAQUE         (SNMP_ASN1_CLASS_APPLICATION | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_APPLICATION_OPAQUE)
+#define SNMP_ASN1_TYPE_COUNTER64      (SNMP_ASN1_CLASS_APPLICATION | SNMP_ASN1_CONTENTTYPE_PRIMITIVE | SNMP_ASN1_APPLICATION_COUNTER64)
+
+typedef u8_t snmp_err_t;
+
+  /* error codes predefined by SNMP prot. */
+#define SNMP_ERR_NOERROR              0
+/* 
+outdated v1 error codes. do not use anmore!
+#define SNMP_ERR_NOSUCHNAME 2 // use SNMP_ERR_NOSUCHINSTANCE instead
+#define SNMP_ERR_BADVALUE   3 // use SNMP_ERR_WRONGTYPE,SNMP_ERR_WRONGLENGTH,SNMP_ERR_WRONGENCODING or SNMP_ERR_WRONGVALUE instead
+#define SNMP_ERR_READONLY   4 // use SNMP_ERR_NOTWRITABLE instead
+*/
+#define SNMP_ERR_GENERROR             5
+#define SNMP_ERR_NOACCESS             6
+#define SNMP_ERR_WRONGTYPE            7
+#define SNMP_ERR_WRONGLENGTH          8
+#define SNMP_ERR_WRONGENCODING        9
+#define SNMP_ERR_WRONGVALUE          10
+#define SNMP_ERR_NOCREATION          11
+#define SNMP_ERR_INCONSISTENTVALUE   12
+#define SNMP_ERR_RESOURCEUNAVAILABLE 13
+#define SNMP_ERR_COMMITFAILED        14
+#define SNMP_ERR_UNDOFAILED          15
+#define SNMP_ERR_NOTWRITABLE         17
+#define SNMP_ERR_INCONSISTENTNAME    18
+
+#define SNMP_VARBIND_EXCEPTION_OFFSET 0xF0
+#define SNMP_VARBIND_EXCEPTION_MASK   0x0F
+#define SNMP_ERR_NOSUCHINSTANCE       SNMP_VARBIND_EXCEPTION_OFFSET + SNMP_ASN1_CONTEXT_VARBIND_NO_SUCH_INSTANCE
+
+
+/** internal object identifier representation */
+struct snmp_obj_id
+{
+  u8_t len;
+  u32_t id[SNMP_MAX_OBJ_ID_LEN];
+};
+
+struct snmp_obj_id_const_ref
+{
+  u8_t len;
+  const u32_t* id;
+};
+
+extern const struct snmp_obj_id_const_ref snmp_zero_dot_zero; /* administrative identifier from SNMPv2-SMI */
+
+union snmp_variant_value
+{
+  void* ptr;
+  const void* const_ptr;
+  u32_t u32;
+  s32_t s32;
+};
+
+#define SNMP_VARIANT_VALUE_TYPE_U32 0
+#define SNMP_VARIANT_VALUE_TYPE_S32 1
+#define SNMP_VARIANT_VALUE_TYPE_PTR 2
+#define SNMP_VARIANT_VALUE_TYPE_CONST_PTR 3
+
+/**
+SNMP MIB node types
+ tree node is the only node the stack can process in order to walk the tree,
+ all other nodes are assumed to be leaf nodes.
+ This cannot be an enum because users may want to define their own node types.
+*/
+#define SNMP_NODE_TREE         0x00
+/* predefined leaf node types */
+#define SNMP_NODE_SCALAR       0x01
+#define SNMP_NODE_SCALAR_ARRAY 0x02
+#define SNMP_NODE_TABLE        0x03
+#define SNMP_NODE_THREADSYNC   0x04
+
+/** node "base class" layout, the mandatory fields for a node  */
+struct snmp_node
+{
+  /** one out of SNMP_NODE_TREE or any leaf node type (like SNMP_NODE_SCALAR) */
+  u8_t node_type;
+  /** the number assigned to this node which used as part of the full OID */
+  u32_t oid;
+};
+
+/* SNMP node instance access types */
+typedef enum {
+  SNMP_NODE_INSTANCE_ACCESS_READ    = 1,
+  SNMP_NODE_INSTANCE_ACCESS_WRITE   = 2,
+  SNMP_NODE_INSTANCE_READ_ONLY      = SNMP_NODE_INSTANCE_ACCESS_READ,
+  SNMP_NODE_INSTANCE_READ_WRITE     = (SNMP_NODE_INSTANCE_ACCESS_READ | SNMP_NODE_INSTANCE_ACCESS_WRITE),
+  SNMP_NODE_INSTANCE_WRITE_ONLY     = SNMP_NODE_INSTANCE_ACCESS_WRITE,
+  SNMP_NODE_INSTANCE_NOT_ACCESSIBLE = 0
+} snmp_access_t;
+
+struct snmp_node_instance;
+
+typedef u16_t (*node_instance_get_value_method)(struct snmp_node_instance*, void*);
+typedef snmp_err_t (*node_instance_set_test_method)(struct snmp_node_instance*, u16_t, void*);
+typedef snmp_err_t (*node_instance_set_value_method)(struct snmp_node_instance*, u16_t, void*);
+typedef void (*node_instance_release_method)(struct snmp_node_instance*);
+
+#define SNMP_GET_VALUE_RAW_DATA 0x8000
+
+struct snmp_node_instance
+{
+  /** prefilled with the node, get_instance() is called on; may be changed by user to any value to pass an arbitrary node between calls to get_instance() and get_value/test_value/set_value */
+  const struct snmp_node* node;
+  /** prefilled with the instance id requested; for get_instance() this is the exact oid requested; for get_next_instance() this is the relative starting point, stack expects relative oid of next node here */
+  struct snmp_obj_id instance_oid;
+
+  /** ASN type for this object (see snmp_asn1.h for definitions) */
+  u8_t asn1_type;
+  /** one out of instance access types defined above (SNMP_NODE_INSTANCE_READ_ONLY,...) */
+  snmp_access_t access;
+  
+  /** returns object value for the given object identifier */
+  node_instance_get_value_method get_value;
+  /** tests length and/or range BEFORE setting */
+  node_instance_set_test_method set_test;
+  /** sets object value, only called when set_test() was successful */
+  node_instance_set_value_method set_value;
+  /** called in any case when the instance is not required anymore by stack (useful for freeing memory allocated in get_instance/get_next_instance methods) */
+  node_instance_release_method release_instance;
+
+  /** reference to pass arbitrary value between calls to get_instance() and get_value/test_value/set_value */
+  union snmp_variant_value reference;
+  /** see reference (if reference is a pointer, the length of underlying data may be stored here or anything else) */
+  u32_t reference_len;
+};
+
+
+struct snmp_tree_node
+{
+  /* inherited "base class" members */
+  struct snmp_node node;
+  u16_t subnode_count;
+  const struct snmp_node* const *subnodes;
+};
+
+#define SNMP_CREATE_TREE_NODE(oid, subnodes) \
+  {{ SNMP_NODE_TREE, (oid) }, \
+  (u16_t)LWIP_ARRAYSIZE(subnodes), (subnodes) }
+
+#define SNMP_CREATE_EMPTY_TREE_NODE(oid) \
+  {{ SNMP_NODE_TREE, (oid) }, \
+  0, NULL }
+
+struct snmp_leaf_node
+{
+  /* inherited "base class" members */
+  struct snmp_node node;
+  u8_t (*get_instance)(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+  u8_t (*get_next_instance)(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+};
+
+/* represents a single mib with its base oid and root node */
+struct snmp_mib
+{
+  const u32_t *base_oid;
+  u8_t base_oid_len;
+  const struct snmp_node *root_node;
+};
+
+#define SNMP_MIB_CREATE(oid_list, root_node) { (oid_list), (u8_t)LWIP_ARRAYSIZE(oid_list), root_node }
+
+/** OID range structure */
+struct snmp_oid_range
+{
+  u32_t min;
+  u32_t max;
+};
+
+/** checks if incoming OID length and values are in allowed ranges */
+u8_t snmp_oid_in_range(const u32_t *oid_in, u8_t oid_len, const struct snmp_oid_range *oid_ranges, u8_t oid_ranges_len);
+
+/** state for next_oid_init / next_oid_check functions */
+struct snmp_next_oid_state
+{
+  const u32_t* start_oid;
+  u8_t start_oid_len;
+
+  u32_t* next_oid;
+  u8_t next_oid_len;
+  u8_t next_oid_max_len;
+  
+  u8_t status;
+  void* reference;
+};
+
+#define SNMP_NEXT_OID_STATUS_SUCCESS      0
+#define SNMP_NEXT_OID_STATUS_NO_MATCH     1
+#define SNMP_NEXT_OID_STATUS_BUF_TO_SMALL 2
+
+/** initialize struct next_oid_state using this function before passing it to next_oid_check */
+void snmp_next_oid_init(struct snmp_next_oid_state *state,
+  const u32_t *start_oid, u8_t start_oid_len,
+  u32_t *next_oid_buf, u8_t next_oid_max_len);
+/** checks if the passed incomplete OID may be a possible candidate for snmp_next_oid_check();
+this methid is intended if the complete OID is not yet known but it is very expensive to build it up,
+so it is possible to test the starting part before building up the complete oid and pass it to snmp_next_oid_check()*/
+u8_t snmp_next_oid_precheck(struct snmp_next_oid_state *state, const u32_t *oid, const u8_t oid_len);
+/** checks the passed OID if it is a candidate to be the next one (get_next); returns !=0 if passed oid is currently closest, otherwise 0 */
+u8_t snmp_next_oid_check(struct snmp_next_oid_state *state, const u32_t *oid, const u8_t oid_len, void* reference);
+
+void snmp_oid_assign(struct snmp_obj_id* target, const u32_t *oid, u8_t oid_len);
+void snmp_oid_combine(struct snmp_obj_id* target, const u32_t *oid1, u8_t oid1_len, const u32_t *oid2, u8_t oid2_len);
+void snmp_oid_prefix(struct snmp_obj_id* target, const u32_t *oid, u8_t oid_len);
+void snmp_oid_append(struct snmp_obj_id* target, const u32_t *oid, u8_t oid_len);
+u8_t snmp_oid_equal(const u32_t *oid1, u8_t oid1_len, const u32_t *oid2, u8_t oid2_len);
+s8_t snmp_oid_compare(const u32_t *oid1, u8_t oid1_len, const u32_t *oid2, u8_t oid2_len);
+
+u8_t snmp_oid_to_ip(const u32_t *oid, ip4_addr_t *ip);
+void snmp_ip_to_oid(const ip4_addr_t *ip, u32_t *oid);
+
+u8_t snmp_set_test_ok(struct snmp_node_instance* instance, u16_t value_len, void* value); /* generic function which can be used if test is always successful */
+
+err_t snmp_decode_bits(const u8_t *buf, u32_t buf_len, u32_t *bit_value);
+err_t snmp_decode_truthvalue(const s32_t *asn1_value, u8_t *bool_value);
+u8_t  snmp_encode_bits(u8_t *buf, u32_t buf_len, u32_t bit_value, u8_t bit_count);
+u8_t  snmp_encode_truthvalue(s32_t *asn1_value, u32_t bool_value);
+
+struct snmp_statistics
+{
+  u32_t inpkts;
+  u32_t outpkts;
+  u32_t inbadversions;
+  u32_t inbadcommunitynames;
+  u32_t inbadcommunityuses;
+  u32_t inasnparseerrs;
+  u32_t intoobigs;
+  u32_t innosuchnames;
+  u32_t inbadvalues;
+  u32_t inreadonlys;
+  u32_t ingenerrs;
+  u32_t intotalreqvars;
+  u32_t intotalsetvars;
+  u32_t ingetrequests;
+  u32_t ingetnexts;
+  u32_t insetrequests;
+  u32_t ingetresponses;
+  u32_t intraps;
+  u32_t outtoobigs;
+  u32_t outnosuchnames;
+  u32_t outbadvalues;
+  u32_t outgenerrs;
+  u32_t outgetrequests;
+  u32_t outgetnexts;
+  u32_t outsetrequests;
+  u32_t outgetresponses;
+  u32_t outtraps;
+};
+
+extern struct snmp_statistics snmp_stats;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_SNMP */
+
+#endif /* LWIP_HDR_APPS_SNMP_CORE_H */
--- a/src/include/lwip/apps/snmp_mib2.h
+++ b/src/include/lwip/apps/snmp_mib2.h
@@ -0,0 +1,79 @@
+/**
+ * @file
+ * MIB2 callback functions called from throughout the stack to integrate a MIB2
+ * into lwIP (together with MIB2_STATS).
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Dirk Ziegelmeier <dziegel@gmx.de>
+ *
+ */
+#ifndef LWIP_HDR_APPS_SNMP_MIB2_H
+#define LWIP_HDR_APPS_SNMP_MIB2_H
+
+#include "lwip/apps/snmp_opts.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+#if SNMP_LWIP_MIB2
+
+#include "lwip/apps/snmp_core.h"
+
+extern const struct snmp_mib mib2;
+
+#if SNMP_USE_NETCONN
+#include "lwip/apps/snmp_threadsync.h"
+void snmp_mib2_lwip_synchronizer(snmp_threadsync_called_fn fn, void* arg);
+extern struct snmp_threadsync_locks snmp_mib2_lwip_locks;
+#endif
+
+#ifndef SNMP_SYSSERVICES
+#define SNMP_SYSSERVICES ((1 << 6) | (1 << 3) | ((IP_FORWARD) << 2))
+#endif
+
+void snmp_mib2_set_sysdescr(const u8_t* str, const u16_t* len); /* read-only be defintion */
+void snmp_mib2_set_syscontact(u8_t *ocstr, u16_t *ocstrlen, u16_t bufsize);
+void snmp_mib2_set_syscontact_readonly(const u8_t *ocstr, const u16_t *ocstrlen);
+void snmp_mib2_set_sysname(u8_t *ocstr, u16_t *ocstrlen, u16_t bufsize);
+void snmp_mib2_set_sysname_readonly(const u8_t *ocstr, const u16_t *ocstrlen);
+void snmp_mib2_set_syslocation(u8_t *ocstr, u16_t *ocstrlen, u16_t bufsize);
+void snmp_mib2_set_syslocation_readonly(const u8_t *ocstr, const u16_t *ocstrlen);
+
+#endif /* SNMP_LWIP_MIB2 */
+#endif /* LWIP_SNMP */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_APPS_SNMP_MIB2_H */
--- a/src/include/lwip/apps/snmp_opts.h
+++ b/src/include/lwip/apps/snmp_opts.h
@@ -29,17 +29,11 @@
 * Author: Dirk Ziegelmeier
 *
 */
-
-#ifndef LWIP_HDR_APPS_SNMP_OPTS_H
-#define LWIP_HDR_APPS_SNMP_OPTS_H
+#ifndef LWIP_HDR_SNMP_OPTS_H
+#define LWIP_HDR_SNMP_OPTS_H

 #include "lwip/opt.h"

-/*
-   ----------------------------------
-   ---------- SNMP options ----------
-   ----------------------------------
-*/
 /**
 * LWIP_SNMP==1: This enables the lwIP SNMP agent. UDP must be available
 * for SNMP transport.
@@ -53,14 +47,47 @@
 #endif

 /**
- * SNMP_CONCURRENT_REQUESTS: Number of concurrent requests the module will
- * allow. At least one request buffer is required.
- * Does not have to be changed unless external MIBs answer request asynchronously
+ * SNMP_USE_NETCONN: Use netconn API instead of raw API.
+ * Makes SNMP agent run in a worker thread, so blocking operations
+ * can be done in MIB calls.
 */
-#ifndef SNMP_CONCURRENT_REQUESTS
-#define SNMP_CONCURRENT_REQUESTS        1
+#ifndef SNMP_USE_NETCONN
+#define SNMP_USE_NETCONN           0
 #endif

+/**
+ * SNMP_USE_RAW: Use raw API.
+ * SNMP agent does not run in a worker thread, so blocking operations
+ * should not be done in MIB calls.
+ */
+#ifndef SNMP_USE_RAW
+#define SNMP_USE_RAW               1
+#endif
+
+#if SNMP_USE_NETCONN && SNMP_USE_RAW
+#error SNMP stack can use only one of the APIs {raw, netconn}
+#endif
+
+#if LWIP_SNMP && !SNMP_USE_NETCONN && !SNMP_USE_RAW
+#error SNMP stack needs a receive API and UDP {raw, netconn}
+#endif
+
+#if SNMP_USE_NETCONN
+/**
+ * SNMP_STACK_SIZE: Stack size of SNMP worker thread
+ */
+#ifndef SNMP_STACK_SIZE
+#define SNMP_STACK_SIZE            DEFAULT_THREAD_STACKSIZE
+#endif
+
+/**
+ * SNMP_THREAD_PRIO: SNMP worker thread priority
+ */
+#ifndef SNMP_THREAD_PRIO
+#define SNMP_THREAD_PRIO           DEFAULT_THREAD_PRIO
+#endif
+#endif /* SNMP_USE_NETCONN */
+
 /**
 * SNMP_TRAP_DESTINATIONS: Number of trap destinations. At least one trap
 * destination is required
@@ -69,15 +96,6 @@
 #define SNMP_TRAP_DESTINATIONS          1
 #endif

-/**
- * SNMP_PRIVATE_MIB:
- * When using a private MIB, you have to create a file 'private_mib.h' that contains
- * a 'struct mib_array_node mib_private' which contains your MIB.
- */
-#ifndef SNMP_PRIVATE_MIB
-#define SNMP_PRIVATE_MIB                0
-#endif
-
 /**
 * Only allow SNMP write actions that are 'safe' (e.g. disabling netifs is not
 * a safe action and disabled when SNMP_SAFE_REQUESTS = 1).
@@ -88,28 +106,26 @@
 #endif

 /**
- * The maximum length of strings used. This affects the size of
- * MEMP_SNMP_VALUE elements.
+ * The maximum length of strings used.
 */
 #ifndef SNMP_MAX_OCTET_STRING_LEN
 #define SNMP_MAX_OCTET_STRING_LEN       127
 #endif

 /**
- * The maximum depth of the SNMP tree.
- * With private MIBs enabled, this depends on your MIB!
- * This affects the size of MEMP_SNMP_VALUE elements.
+ * The maximum number of Sub ID's inside an object identifier.
+ * Indirectly this also limits the maximum depth of SNMP tree.
 */
-#ifndef SNMP_MAX_TREE_DEPTH
-#define SNMP_MAX_TREE_DEPTH             15
+#ifndef SNMP_MAX_OBJ_ID_LEN
+#define SNMP_MAX_OBJ_ID_LEN             32
 #endif

 /**
- * The size of the MEMP_SNMP_VALUE elements, normally calculated from
- * SNMP_MAX_OCTET_STRING_LEN and SNMP_MAX_TREE_DEPTH.
+ * The maximum size of a value.
 */
 #ifndef SNMP_MAX_VALUE_SIZE
-#define SNMP_MAX_VALUE_SIZE             LWIP_MAX((SNMP_MAX_OCTET_STRING_LEN)+1, sizeof(s32_t)*(SNMP_MAX_TREE_DEPTH))
+#define SNMP_MIN_VALUE_SIZE             (2 * sizeof(u32_t*)) // size required to store the basic types (8 bytes for counter64)
+#define SNMP_MAX_VALUE_SIZE             LWIP_MAX(LWIP_MAX((SNMP_MAX_OCTET_STRING_LEN), sizeof(u32_t)*(SNMP_MAX_OBJ_ID_LEN)), SNMP_MIN_VALUE_SIZE)
 #endif

 /**
@@ -120,16 +136,9 @@
 #define SNMP_COMMUNITY                  "public"
 #endif

-/**
- * Set this to 1 to enable support for dedicated write-access and trap communities.
- */
-#ifndef SNMP_COMMUNITY_EXT
-#define SNMP_COMMUNITY_EXT              0
-#endif
-
-#if SNMP_COMMUNITY_EXT
 /**
 * The snmp write-access community.
+ * Set this community to "" in order to disallow any write access.
 */
 #ifndef SNMP_COMMUNITY_WRITE
 #define SNMP_COMMUNITY_WRITE            "private"
@@ -141,48 +150,43 @@
 #ifndef SNMP_COMMUNITY_TRAP
 #define SNMP_COMMUNITY_TRAP             "public"
 #endif
-#endif /* SNMP_COMMUNITY_EXT */

 /**
- * SNMP_NUM_NODE: the number of leafs in the SNMP tree.
+ * The maximum length of community string.
+ * If community names shall be adjusted at runtime via snmp_set_community() calls,
+ * enter here the possible maximum length (+1 for terminating null character).
 */
-#ifndef SNMP_NUM_NODE
-#define SNMP_NUM_NODE              50
+#ifndef SNMP_MAX_COMMUNITY_STR_LEN
+#define SNMP_MAX_COMMUNITY_STR_LEN LWIP_MAX(LWIP_MAX(sizeof(SNMP_COMMUNITY), sizeof(SNMP_COMMUNITY_WRITE)), sizeof(SNMP_COMMUNITY_TRAP))
 #endif

 /**
- * SNMP_NUM_ROOTNODE: the number of branches in the SNMP tree.
- * Every branch has one leaf (MEMP_NUM_SNMP_NODE) at least!
+ * The OID identifiying the device. This may be the enterprise OID itself or any OID located below it in tree.
 */
-#ifndef SNMP_NUM_ROOTNODE
-#define SNMP_NUM_ROOTNODE          30
+#ifndef SNMP_DEVICE_ENTERPRISE_OID
+/**
+ * IANA assigned enterprise ID for lwIP is 26381
+ * @see http://www.iana.org/assignments/enterprise-numbers
+ *
+ * @note this enterprise ID is assigned to the lwIP project,
+ * all object identifiers living under this ID are assigned
+ * by the lwIP maintainers!
+ * @note don't change this define, use snmp_set_device_enterprise_oid()
+ *
+ * If you need to create your own private MIB you'll need
+ * to apply for your own enterprise ID with IANA:
+ * http://www.iana.org/numbers.html
+ */
+#define SNMP_LWIP_ENTERPRISE_OID 26381
+#define SNMP_DEVICE_ENTERPRISE_OID {1, 3, 6, 1, 4, 1, SNMP_LWIP_ENTERPRISE_OID}
+#define SNMP_DEVICE_ENTERPRISE_OID_LEN 7
 #endif

 /**
- * SNMP_NUM_VARBIND: influences the number of concurrent requests:
- * 2 of these are used per request (1 for input, 1 for output), so this needs
- * to be increased only if you want to support concurrent requests or multiple
- * variables per request/response.
+ * SNMP_DEBUG: Enable debugging for SNMP messages.
 */
-#ifndef SNMP_NUM_VARBIND
-#define SNMP_NUM_VARBIND           2
-#endif
-
-/**
- * SNMP_NUM_VALUE: the number of OID or values concurrently used
- * (does not have to be changed normally) - >=3 of these are used per request
- * (1 for the value read and 2 for OIDs - input and output on getnext, or more
- * if you want to support multiple varibles per request/response)
- */
-#ifndef SNMP_NUM_VALUE
-#define SNMP_NUM_VALUE             3
-#endif
-
-/**
- * SNMP_MSG_DEBUG: Enable debugging for SNMP messages.
- */
-#ifndef SNMP_MSG_DEBUG
-#define SNMP_MSG_DEBUG                  LWIP_DBG_OFF
+#ifndef SNMP_DEBUG
+#define SNMP_DEBUG                      LWIP_DBG_OFF
 #endif

 /**
@@ -192,4 +196,54 @@
 #define SNMP_MIB_DEBUG                  LWIP_DBG_OFF
 #endif

-#endif	/* LWIP_HDR_APPS_SNMP_OPTS_H */
+/**
+ * Indicates if the MIB2 implementation of LWIP SNMP stack is used.
+ */
+#ifndef SNMP_LWIP_MIB2
+#define SNMP_LWIP_MIB2                      LWIP_SNMP
+#endif
+
+/**
+ * Value return for sysDesc field of MIB2.
+ */
+#ifndef SNMP_LWIP_MIB2_SYSDESC
+#define SNMP_LWIP_MIB2_SYSDESC              "lwIP"
+#endif
+
+/**
+ * Value return for sysName field of MIB2.
+ * To make sysName field settable, call snmp_mib2_set_sysname() to provide the necessary buffers.
+ */
+#ifndef SNMP_LWIP_MIB2_SYSNAME
+#define SNMP_LWIP_MIB2_SYSNAME              "FQDN-unk"
+#endif
+
+/**
+ * Value return for sysContact field of MIB2.
+ * To make sysContact field settable, call snmp_mib2_set_syscontact() to provide the necessary buffers.
+ */
+#ifndef SNMP_LWIP_MIB2_SYSCONTACT
+#define SNMP_LWIP_MIB2_SYSCONTACT           ""
+#endif
+
+/**
+ * Value return for sysLocation field of MIB2.
+ * To make sysLocation field settable, call snmp_mib2_set_syslocation() to provide the necessary buffers.
+ */
+#ifndef SNMP_LWIP_MIB2_SYSLOCATION
+#define SNMP_LWIP_MIB2_SYSLOCATION          ""
+#endif
+
+/**
+ * This value is used to limit the repetitions processed in GetBulk requests (value == 0 means no limitation).
+ * This may be useful to limit the load for a single request.
+ * According to SNMP RFC 1905 it is allowed to not return all requested variables from a GetBulk request if system load would be too high.
+ * so the effect is that the client will do more requests to gather all data.
+ * For the stack this could be useful in case that SNMP processing is done in TCP/IP thread. In this situation a request with many
+ * repetitions could block the thread for a longer time. Setting limit here will keep the stack more responsive.
+ */
+#ifndef SNMP_LWIP_GETBULK_MAX_REPETITIONS
+#define SNMP_LWIP_GETBULK_MAX_REPETITIONS 0
+#endif
+
+#endif /* SNMP_LWIP_MIB2 */
--- a/src/include/lwip/apps/snmp_scalar.h
+++ b/src/include/lwip/apps/snmp_scalar.h
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Martin Hentschel <info@cl-soft.de>
+ *
+ */
+
+#ifndef LWIP_HDR_APPS_SNMP_SCALAR_H
+#define LWIP_HDR_APPS_SNMP_SCALAR_H
+
+#include "lwip/apps/snmp_opts.h"
+#include "lwip/apps/snmp_core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+/* basic scalar node */
+
+struct snmp_scalar_node
+{
+  /* inherited "base class" members */
+  struct snmp_leaf_node node;
+  u8_t asn1_type;
+  snmp_access_t access;
+  node_instance_get_value_method get_value;
+  node_instance_set_test_method set_test;
+  node_instance_set_value_method set_value;
+};
+
+
+snmp_err_t snmp_scalar_get_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+snmp_err_t snmp_scalar_get_next_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+
+#define SNMP_SCALAR_CREATE_NODE(oid, access, asn1_type, get_value_method, set_test_method, set_value_method) \
+  {{{ SNMP_NODE_SCALAR, (oid) }, \
+    snmp_scalar_get_instance, \
+    snmp_scalar_get_next_instance }, \
+    (asn1_type), (access), (get_value_method), (set_test_method), (set_value_method) }
+
+#define SNMP_SCALAR_CREATE_NODE_READONLY(oid, asn1_type, get_value_method) SNMP_SCALAR_CREATE_NODE(oid, SNMP_NODE_INSTANCE_READ_ONLY, asn1_type, get_value_method, NULL, NULL)
+
+/* scalar array node - a tree node which contains scalars only as children */
+struct snmp_scalar_array_node_def
+{
+  u32_t         oid;
+  u8_t          asn1_type;
+  snmp_access_t access;
+};
+
+typedef u16_t (*snmp_scalar_array_get_value_method)(const struct snmp_scalar_array_node_def*, void*);
+typedef snmp_err_t (*snmp_scalar_array_set_test_method)(const struct snmp_scalar_array_node_def*, u16_t, void*);
+typedef snmp_err_t (*snmp_scalar_array_set_value_method)(const struct snmp_scalar_array_node_def*, u16_t, void*);
+
+struct snmp_scalar_array_node
+{
+  /* inherited "base class" members */
+  struct snmp_leaf_node node;
+  u16_t array_node_count;
+  const struct snmp_scalar_array_node_def* array_nodes;
+  snmp_scalar_array_get_value_method get_value;
+  snmp_scalar_array_set_test_method set_test;
+  snmp_scalar_array_set_value_method set_value;
+};
+
+snmp_err_t snmp_scalar_array_get_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+snmp_err_t snmp_scalar_array_get_next_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+
+#define SNMP_SCALAR_CREATE_ARRAY_NODE(oid, array_nodes, get_value_method, set_test_method, set_value_method) \
+  {{{ SNMP_NODE_SCALAR_ARRAY, (oid) }, \
+    snmp_scalar_array_get_instance, \
+    snmp_scalar_array_get_next_instance }, \
+    (u16_t)LWIP_ARRAYSIZE(array_nodes), (array_nodes), (get_value_method), (set_test_method), (set_value_method) }
+
+#endif /* LWIP_SNMP */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_APPS_SNMP_SCALAR_H */
--- a/src/include/lwip/apps/snmp_structs.h
+++ b/src/include/lwip/apps/snmp_structs.h
@@ -1,271 +0,0 @@
-/**
- * @file
- * Generic MIB tree structures.
- *
- * @todo namespace prefixes
- */
-
-/*
- * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- *    this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- * 3. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
- * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
- * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
- * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
- * OF SUCH DAMAGE.
- *
- * Author: Christiaan Simons <christiaan.simons@axon.tv>
- */
-
-#ifndef LWIP_HDR_APPS_SNMP_STRUCTS_H
-#define LWIP_HDR_APPS_SNMP_STRUCTS_H
-
-#include "lwip/opt.h"
-
-#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
-
-#include "lwip/apps/snmp.h"
-#include "lwip/memp.h"
-
-LWIP_MEMPOOL_PROTOTYPE(SNMP_ROOTNODE);
-LWIP_MEMPOOL_PROTOTYPE(SNMP_NODE);
-
-#if SNMP_PRIVATE_MIB
-/* When using a private MIB, you have to create a file 'private_mib.h' that contains
- * a 'struct mib_array_node mib_private' which contains your MIB. */
-#include "private_mib.h"
-#endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* MIB object instance */
-#define MIB_OBJECT_NONE 0
-#define MIB_OBJECT_SCALAR 1
-#define MIB_OBJECT_TAB 2
-
-/* MIB access types */
-#define MIB_ACCESS_READ   1
-#define MIB_ACCESS_WRITE  2
-
-/* MIB object access */
-#define MIB_OBJECT_READ_ONLY      MIB_ACCESS_READ
-#define MIB_OBJECT_READ_WRITE     (MIB_ACCESS_READ | MIB_ACCESS_WRITE)
-#define MIB_OBJECT_WRITE_ONLY     MIB_ACCESS_WRITE
-#define MIB_OBJECT_NOT_ACCESSIBLE 0
-
-/** object definition returned by (get_object_def)() */
-struct obj_def
-{
-  /* MIB_OBJECT_NONE (0), MIB_OBJECT_SCALAR (1), MIB_OBJECT_TAB (2) */
-  u8_t instance;
-  /* 0 read-only, 1 read-write, 2 write-only, 3 not-accessible */
-  u8_t access;
-  /* ASN type for this object */
-  u8_t asn_type;
-  /* length of instance part of supplied object identifier */
-  u8_t  id_inst_len;
-  /* instance part of supplied object identifier */
-  s32_t *id_inst_ptr;
-};
-
-struct snmp_name_ptr
-{
-  u8_t ident_len;
-  s32_t *ident;
-};
-
-/** MIB const scalar (.0) node */
-#define MIB_NODE_SC 0x01
-/** MIB const array node */
-#define MIB_NODE_AR 0x02
-/** MIB list root node (memp_malloced from RAM) */
-#define MIB_NODE_LR 0x04
-/** MIB node for external objects */
-#define MIB_NODE_EX 0x05
-
-/** node "base class" layout, the mandatory fields for a node  */
-struct mib_node
-{
-  /** One out of MIB_NODE_AR, MIB_NODE_LR or MIB_NODE_EX */
-  u8_t node_type;
-};
-
-/** derived node for scalars .0 index */
-struct mib_scalar_node
-{
-  /* inherited "base class" members */
-  struct mib_node node;
-  /** returns struct obj_def for the given object identifier */
-  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
-  /** returns object value for the given object identifier */
-  u16_t (*get_value)(struct obj_def *od, void *value);
-  /** tests length and/or range BEFORE setting */
-  u8_t (*set_test)(struct obj_def *od, u16_t len, void *value);
-  /** sets object value, only to be called when set_test()  */
-  void (*set_value)(struct obj_def *od, u16_t len, void *value);
-};
-
-/** describes an array entry (objid/node pair) */
-struct mib_array_node_entry
-{
-  s32_t objid;
-  const struct mib_node *nptr;
-};
-
-/** derived node, points to a fixed size array
-    of sub-identifiers plus a 'child' pointer */
-struct mib_array_node
-{
-  /* inherited "base class" members */
-  struct mib_node node;
-
-  /* additional struct members */
-  u16_t maxlength;
-  const struct mib_array_node_entry *entries;
-};
-
-struct mib_list_node
-{
-  struct mib_list_node *prev;
-  struct mib_list_node *next;
-  s32_t objid;
-  struct mib_node *nptr;
-};
-
-/** derived node, points to a doubly linked list
-    of sub-identifiers plus a 'child' pointer */
-struct mib_list_rootnode
-{
-  /* inherited "base class" members */
-  struct mib_scalar_node scalar;
-
-  /* additional struct members */
-  struct mib_list_node *head;
-  struct mib_list_node *tail;
-  /* counts list nodes in list  */
-  u16_t count;
-};
-
-/** derived node, has access functions for mib object in external memory or device
-    using 'tree_level' and 'idx', with a range 0 .. (level_length() - 1) */
-struct mib_external_node
-{
-  /* inherited "base class" members */
-  struct mib_node node;
-
-  /* additional struct members */
-  /** points to an external (in memory) record of some sort of addressing
-      information, passed to and interpreted by the functions below */
-  void* addr_inf;
-  /** tree levels under this node */
-  u8_t tree_levels;
-  /** number of objects at this level */
-  u16_t (*level_length)(void* addr_inf, u8_t level);
-  /** compares object sub identifier with external id
-      return zero when equal, nonzero when unequal */
-  s32_t (*ident_cmp)(void* addr_inf, u8_t level, u16_t idx, s32_t sub_id);
-  void (*get_objid)(void* addr_inf, u8_t level, u16_t idx, s32_t *sub_id);
-
-  /** async Questions */
-  void (*get_object_def_q)(void* addr_inf, u8_t rid, u8_t ident_len, s32_t *ident);
-  void (*get_value_q)(u8_t rid, struct obj_def *od);
-  void (*set_test_q)(u8_t rid, struct obj_def *od);
-  void (*set_value_q)(u8_t rid, struct obj_def *od, u16_t len, void *value);
-  /** async Answers */
-  void (*get_object_def_a)(u8_t rid, u8_t ident_len, s32_t *ident, struct obj_def *od);
-  u16_t (*get_value_a)(u8_t rid, struct obj_def *od, void *value);
-  u8_t (*set_test_a)(u8_t rid, struct obj_def *od, u16_t len, void *value);
-  void (*set_value_a)(u8_t rid, struct obj_def *od, u16_t len, void *value);
-  /** async Panic Close (agent returns error reply,
-      e.g. used for external transaction cleanup) */
-  void (*get_object_def_pc)(u8_t rid, u8_t ident_len, s32_t *ident);
-  void (*get_value_pc)(u8_t rid, struct obj_def *od);
-  void (*set_test_pc)(u8_t rid, struct obj_def *od);
-  void (*set_value_pc)(u8_t rid, struct obj_def *od);
-};
-
-/** export MIB tree from mib2.c */
-extern const struct mib_array_node internet;
-
-/** dummy function pointers for non-leaf MIB nodes from mib2.c */
-void noleafs_get_object_def(u8_t ident_len, s32_t *ident, struct obj_def *od);
-u16_t noleafs_get_value(struct obj_def *od, void *value);
-u8_t noleafs_set_test(struct obj_def *od, u16_t len, void *value);
-void noleafs_set_value(struct obj_def *od, u16_t len, void *value);
-
-void snmp_oidtoip(s32_t *ident, ip4_addr_t *ip);
-void snmp_iptooid(const ip4_addr_t *ip, s32_t *ident);
-void snmp_ifindextonetif(s32_t ifindex, struct netif **netif);
-void snmp_netiftoifindex(struct netif *netif, s32_t *ifidx);
-
-struct mib_list_node* snmp_mib_ln_alloc(s32_t id);
-void snmp_mib_ln_free(struct mib_list_node *ln);
-struct mib_list_rootnode* snmp_mib_lrn_alloc(void);
-void snmp_mib_lrn_free(struct mib_list_rootnode *lrn);
-
-s8_t snmp_mib_node_insert(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **insn);
-s8_t snmp_mib_node_find(struct mib_list_rootnode *rn, s32_t objid, struct mib_list_node **fn);
-struct mib_list_rootnode *snmp_mib_node_delete(struct mib_list_rootnode *rn, struct mib_list_node *n);
-
-const struct mib_node* snmp_search_tree(const struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_name_ptr *np);
-const struct mib_node* snmp_expand_tree(const struct mib_node *node, u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);
-u8_t snmp_iso_prefix_tst(u8_t ident_len, s32_t *ident);
-u8_t snmp_iso_prefix_expand(u8_t ident_len, s32_t *ident, struct snmp_obj_id *oidret);
-
-/* SNMP stack internal MIB2 statistics */
-void mib2_inc_snmpinpkts(void);
-void mib2_inc_snmpoutpkts(void);
-void mib2_inc_snmpinbadversions(void);
-void mib2_inc_snmpinbadcommunitynames(void);
-void mib2_inc_snmpinbadcommunityuses(void);
-void mib2_inc_snmpinasnparseerrs(void);
-void mib2_inc_snmpintoobigs(void);
-void mib2_inc_snmpinnosuchnames(void);
-void mib2_inc_snmpinbadvalues(void);
-void mib2_inc_snmpinreadonlys(void);
-void mib2_inc_snmpingenerrs(void);
-void mib2_add_snmpintotalreqvars(u8_t value);
-void mib2_add_snmpintotalsetvars(u8_t value);
-void mib2_inc_snmpingetrequests(void);
-void mib2_inc_snmpingetnexts(void);
-void mib2_inc_snmpinsetrequests(void);
-void mib2_inc_snmpingetresponses(void);
-void mib2_inc_snmpintraps(void);
-void mib2_inc_snmpouttoobigs(void);
-void mib2_inc_snmpoutnosuchnames(void);
-void mib2_inc_snmpoutbadvalues(void);
-void mib2_inc_snmpoutgenerrs(void);
-void mib2_inc_snmpoutgetrequests(void);
-void mib2_inc_snmpoutgetnexts(void);
-void mib2_inc_snmpoutsetrequests(void);
-void mib2_inc_snmpoutgetresponses(void);
-void mib2_inc_snmpouttraps(void);
-void mib2_get_snmpgrpid_ptr(const struct snmp_obj_id **oid);
-void mib2_get_snmpenableauthentraps(u8_t *value);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* LWIP_SNMP */
-
-#endif /* LWIP_HDR_APPS_SNMP_STRUCTS_H */
--- a/src/include/lwip/apps/snmp_table.h
+++ b/src/include/lwip/apps/snmp_table.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Martin Hentschel <info@cl-soft.de>
+ *
+ */
+
+#ifndef LWIP_HDR_APPS_SNMP_TABLE_H
+#define LWIP_HDR_APPS_SNMP_TABLE_H
+
+#include "lwip/apps/snmp_opts.h"
+#include "lwip/apps/snmp_core.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+/* default (customizable) read/write table */
+
+struct snmp_table_col_def
+{
+  u32_t index;
+  u8_t asn1_type;
+  snmp_access_t access;
+};
+
+struct snmp_table_node
+{
+  /* inherited "base class" members */
+  struct snmp_leaf_node node;
+  u16_t column_count;
+  const struct snmp_table_col_def* columns;
+  snmp_err_t (*get_cell_instance)(const u32_t* column, const u32_t* row_oid, const u8_t row_oid_len, struct snmp_node_instance* cell_instance);
+  snmp_err_t (*get_next_cell_instance)(const u32_t* column, struct snmp_obj_id* row_oid, struct snmp_node_instance* cell_instance);
+  /** returns object value for the given object identifier */
+  node_instance_get_value_method get_value;
+  /** tests length and/or range BEFORE setting */
+  node_instance_set_test_method set_test;
+  /** sets object value, only called when set_test() was successful */
+  node_instance_set_value_method set_value;
+};
+
+snmp_err_t snmp_table_get_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+snmp_err_t snmp_table_get_next_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+
+#define SNMP_TABLE_CREATE(oid, columns, get_cell_instance_method, get_next_cell_instance_method, get_value_method, set_test_method, set_value_method) \
+  {{{ SNMP_NODE_TABLE, (oid) }, \
+  snmp_table_get_instance, \
+  snmp_table_get_next_instance }, \
+  (u16_t)LWIP_ARRAYSIZE(columns), (columns), \
+  (get_cell_instance_method), (get_next_cell_instance_method), \
+  (get_value_method), (set_test_method), (set_value_method)}
+
+#define SNMP_TABLE_GET_COLUMN_FROM_OID(oid) ((oid)[1]) /* first array value is (fixed) row entry (fixed to 1) and 2nd value is column, follow3ed by instance */
+
+  
+/* simple read-only table */
+
+struct snmp_table_simple_col_def
+{
+  u32_t index;
+  u8_t asn1_type;
+  u8_t data_type; /* any of SNMP_VARIANT_VALUE_TYPE_*, depending of what union member is used to store the value*/
+};
+
+struct snmp_table_simple_node
+{
+  /* inherited "base class" members */
+  struct snmp_leaf_node node;
+  u16_t column_count;
+  const struct snmp_table_simple_col_def* columns;
+  snmp_err_t (*get_cell_value)(const u32_t* column, const u32_t* row_oid, const u8_t row_oid_len, union snmp_variant_value* value, u32_t* value_len);
+  snmp_err_t (*get_next_cell_instance_and_value)(const u32_t* column, struct snmp_obj_id* row_oid, union snmp_variant_value* value, u32_t* value_len);
+};
+
+snmp_err_t snmp_table_simple_get_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+snmp_err_t snmp_table_simple_get_next_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+
+#define SNMP_TABLE_CREATE_SIMPLE(oid, columns, get_cell_value_method, get_next_cell_instance_and_value_method) \
+  {{{ SNMP_NODE_TABLE, (oid) }, \
+  snmp_table_simple_get_instance, \
+  snmp_table_simple_get_next_instance }, \
+  (u16_t)LWIP_ARRAYSIZE(columns), (columns), (get_cell_value_method), (get_next_cell_instance_and_value_method) }
+
+u16_t snmp_table_extract_value_from_s32ref(struct snmp_node_instance* instance, void* value);
+u16_t snmp_table_extract_value_from_u32ref(struct snmp_node_instance* instance, void* value);
+u16_t snmp_table_extract_value_from_refconstptr(struct snmp_node_instance* instance, void* value);
+
+#endif /* LWIP_SNMP */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_APPS_SNMP_TABLE_H */
--- a/src/include/lwip/apps/snmp_threadsync.h
+++ b/src/include/lwip/apps/snmp_threadsync.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Dirk Ziegelmeier <dziegel@gmx.de>
+ *
+ */
+
+#ifndef LWIP_HDR_APPS_SNMP_THREADSYNC_H
+#define LWIP_HDR_APPS_SNMP_THREADSYNC_H
+
+#include "lwip/apps/snmp_opts.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/apps/snmp_core.h"
+#include "lwip/sys.h"
+
+typedef void (*snmp_threadsync_called_fn)(void* arg);
+typedef void (*snmp_threadsync_synchronizer_fn)(snmp_threadsync_called_fn fn, void* arg);
+
+struct snmp_threadsync_locks
+{
+  sys_sem_t                       sem;
+  sys_mutex_t                     sem_usage_mutex;
+  snmp_threadsync_synchronizer_fn sync_fn;
+};
+
+/* thread sync node */
+struct snmp_threadsync_node
+{
+  /* inherited "base class" members */
+  struct snmp_leaf_node node;
+  const struct snmp_leaf_node *target;
+  struct snmp_threadsync_locks *locks;
+};
+
+snmp_err_t snmp_threadsync_get_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+snmp_err_t snmp_threadsync_get_next_instance(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
+
+#define SNMP_CREATE_THREAD_SYNC_NODE(oid, target, locks) \
+  {{{ SNMP_NODE_THREADSYNC, (oid) }, \
+    snmp_threadsync_get_instance, \
+    snmp_threadsync_get_next_instance }, \
+    (target), \
+    (locks) }
+
+void snmp_threadsync_init(struct snmp_threadsync_locks *locks, snmp_threadsync_synchronizer_fn sync_fn);
+
+#endif /* LWIP_SNMP */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_APPS_SNMP_THREADSYNC_H */