snmp_core.h

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/*
 * 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)

#define SNMP_VARBIND_EXCEPTION_OFFSET 0xF0
#define SNMP_VARBIND_EXCEPTION_MASK   0x0F

/* error codes predefined by SNMP prot. */
typedef enum {
  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
*/
  SNMP_ERR_GENERROR            = 5,
  SNMP_ERR_NOACCESS            = 6,
  SNMP_ERR_WRONGTYPE           = 7,
  SNMP_ERR_WRONGLENGTH         = 8,
  SNMP_ERR_WRONGENCODING       = 9,
  SNMP_ERR_WRONGVALUE          = 10,
  SNMP_ERR_NOCREATION          = 11,
  SNMP_ERR_INCONSISTENTVALUE   = 12,
  SNMP_ERR_RESOURCEUNAVAILABLE = 13,
  SNMP_ERR_COMMITFAILED        = 14,
  SNMP_ERR_UNDOFAILED          = 15,
  SNMP_ERR_NOTWRITABLE         = 17,
  SNMP_ERR_INCONSISTENTNAME    = 18,

  SNMP_ERR_NOSUCHINSTANCE      = SNMP_VARBIND_EXCEPTION_OFFSET + SNMP_ASN1_CONTEXT_VARBIND_NO_SUCH_INSTANCE
} snmp_err_t;

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_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

struct snmp_node
{
  u8_t node_type;
  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
{
  const struct snmp_node* node;
  struct snmp_obj_id instance_oid;

  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;
  node_instance_release_method release_instance;

  union snmp_variant_value reference;
  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;
  snmp_err_t (*get_instance)(const u32_t *root_oid, u8_t root_oid_len, struct snmp_node_instance* instance);
  snmp_err_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 }

struct snmp_oid_range
{
  u32_t min;
  u32_t max;
};

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);

typedef enum {
  SNMP_NEXT_OID_STATUS_SUCCESS,
  SNMP_NEXT_OID_STATUS_NO_MATCH,
  SNMP_NEXT_OID_STATUS_BUF_TO_SMALL
} snmp_next_oid_status_t;

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;
  
  snmp_next_oid_status_t status;
  void* reference;
};

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);
u8_t snmp_next_oid_precheck(struct snmp_next_oid_state *state, const u32_t *oid, const u8_t oid_len);
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);

#if LWIP_IPV4
u8_t snmp_oid_to_ip4(const u32_t *oid, ip4_addr_t *ip);
void snmp_ip4_to_oid(const ip4_addr_t *ip, u32_t *oid);
#endif /* LWIP_IPV4 */
#if LWIP_IPV6
u8_t snmp_oid_to_ip6(const u32_t *oid, ip6_addr_t *ip);
void snmp_ip6_to_oid(const ip6_addr_t *ip, u32_t *oid);
#endif /* LWIP_IPV6 */
#if LWIP_IPV4 || LWIP_IPV6
u8_t snmp_ip_to_oid(const ip_addr_t *ip, u32_t *oid);
u8_t snmp_ip_port_to_oid(const ip_addr_t *ip, u16_t port, u32_t *oid);

u8_t snmp_oid_to_ip(const u32_t *oid, u8_t oid_len, ip_addr_t *ip);
u8_t snmp_oid_to_ip_port(const u32_t *oid, u8_t oid_len, ip_addr_t *ip, u16_t *port);
#endif /* LWIP_IPV4 || LWIP_IPV6 */

snmp_err_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 */