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+/**
+ * @file
+ * MIB tree access/construction functions.
+ */
+
+/*
+ * 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>
+*/
+
+/**
+ * @defgroup snmp SNMPv2c agent
+ * @ingroup apps
+ * SNMPv2c compatible agent\n
+ * There is also a MIB compiler and a MIB viewer in lwIP contrib repository
+ * (lwip-contrib/apps/LwipMibCompiler).\n
+ * The agent implements the most important MIB2 MIBs including IPv6 support
+ * (interfaces, UDP, TCP, SNMP, ICMP, SYSTEM). IP MIB is an older version
+ * whithout IPv6 statistics (TODO).\n
+ * Rewritten by Martin Hentschel <info@cl-soft.de> and
+ * Dirk Ziegelmeier <dziegel@gmx.de>\n
+ * Work on SNMPv3 has started, but is not finished.\n
+ *
+ * 0 Agent Capabilities
+ * ====================
+ *
+ * Features:
+ * ---------
+ * - SNMPv2c support.
+ * - Low RAM usage - no memory pools, stack only.
+ * - MIB2 implementation is separated from SNMP stack.
+ * - Support for multiple MIBs (snmp_set_mibs() call) - e.g. for private MIB.
+ * - Simple and generic API for MIB implementation.
+ * - Comfortable node types and helper functions for scalar arrays and tables.
+ * - Counter64, bit and truthvalue datatype support.
+ * - Callbacks for SNMP writes e.g. to implement persistency.
+ * - 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 where no locking is
+ * possible. Used in MIB2 to access lwIP stats from lwIP thread.
+ *
+ * MIB compiler (code generator):
+ * ------------------------------
+ * - Provided in lwIP contrib repository.
+ * - Written in C#. MIB viewer used Windows Forms.
+ * - Developed on Windows with Visual Studio 2010.
+ * - Can be compiled and used on all platforms with http://www.monodevelop.com/.
+ * - Based on a heavily modified version of of SharpSnmpLib (a4bd05c6afb4)
+ * (https://sharpsnmplib.codeplex.com/SourceControl/network/forks/Nemo157/MIBParserUpdate).
+ * - MIB parser, C file generation framework and LWIP code generation are cleanly
+ * separated, which means the code may be useful as a base for code generation
+ * of other SNMP agents.
+ *
+ * Notes:
+ * ------
+ * - Stack and MIB compiler were used to implement a Profinet device.
+ * Compiled/implemented MIBs: LLDP-MIB, LLDP-EXT-DOT3-MIB, LLDP-EXT-PNO-MIB.
+ *
+ * SNMPv1 per RFC1157 and SNMPv2c per RFC 3416
+ * -------------------------------------------
+ * Note the S in SNMP stands for "Simple". Note that "Simple" is
+ * relative. SNMP is simple compared to the complex ISO network
+ * management protocols CMIP (Common Management Information Protocol)
+ * and CMOT (CMip Over Tcp).
+ *
+ * MIB II
+ * ------
+ * The standard lwIP stack management information base.
+ * This is a required MIB, so this is always enabled.
+ * The groups EGP, CMOT and transmission are disabled by default.
+ *
+ * Most mib-2 objects are not writable except:
+ * sysName, sysLocation, sysContact, snmpEnableAuthenTraps.
+ * Writing to or changing the ARP and IP address and route
+ * tables is not possible.
+ *
+ * Note lwIP has a very limited notion of IP routing. It currently
+ * doen't have a route table and doesn't have a notion of the U,G,H flags.
+ * Instead lwIP uses the interface list with only one default interface
+ * acting as a single gateway interface (G) for the default route.
+ *
+ * The agent returns a "virtual table" with the default route 0.0.0.0
+ * for the default interface and network routes (no H) for each
+ * network interface in the netif_list.
+ * All routes are considered to be up (U).
+ *
+ * Loading additional MIBs
+ * -----------------------
+ * MIBs can only be added in compile-time, not in run-time.
+ *
+ *
+ * 1 Building the Agent
+ * ====================
+ * First of all you'll need to add the following define
+ * to your local lwipopts.h:
+ * \#define LWIP_SNMP 1
+ *
+ * and add the source files your makefile.
+ *
+ * Note you'll might need to adapt you network driver to update
+ * the mib2 variables for your interface.
+ *
+ * 2 Running the Agent
+ * ===================
+ * The following function calls must be made in your program to
+ * actually get the SNMP agent running.
+ *
+ * Before starting the agent you should supply pointers
+ * for sysContact, sysLocation, and snmpEnableAuthenTraps.
+ * You can do this by calling
+ *
+ * - snmp_mib2_set_syscontact()
+ * - snmp_mib2_set_syslocation()
+ * - snmp_set_auth_traps_enabled()
+ *
+ * You can register a callback which is called on successful write access:
+ * snmp_set_write_callback().
+ *
+ * Additionally you may want to set
+ *
+ * - snmp_mib2_set_sysdescr()
+ * - snmp_set_device_enterprise_oid()
+ * - snmp_mib2_set_sysname()
+ *
+ * Also before starting the agent you need to setup
+ * one or more trap destinations using these calls:
+ *
+ * - snmp_trap_dst_enable()
+ * - snmp_trap_dst_ip_set()
+ *
+ * If you need more than MIB2, set the MIBs you want to use
+ * by snmp_set_mibs().
+ *
+ * Finally, enable the agent by calling snmp_init()
+ *
+ * @defgroup snmp_core Core
+ * @ingroup snmp
+ *
+ * @defgroup snmp_traps Traps
+ * @ingroup snmp
+ */
+
+#include "lwip/apps/snmp_opts.h"
+
+#if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/apps/snmp.h"
+#include "lwip/apps/snmp_core.h"
+#include "snmp_core_priv.h"
+#include "lwip/netif.h"
+#include <string.h>
+
+
+#if (LWIP_SNMP && (SNMP_TRAP_DESTINATIONS<=0))
+ #error "If you want to use SNMP, you have to define SNMP_TRAP_DESTINATIONS>=1 in your lwipopts.h"
+#endif
+#if (!LWIP_UDP && LWIP_SNMP)
+ #error "If you want to use SNMP, you have to define LWIP_UDP=1 in your lwipopts.h"
+#endif
+
+struct snmp_statistics snmp_stats;
+static const struct snmp_obj_id snmp_device_enterprise_oid_default = {SNMP_DEVICE_ENTERPRISE_OID_LEN, SNMP_DEVICE_ENTERPRISE_OID};
+static const struct snmp_obj_id* snmp_device_enterprise_oid = &snmp_device_enterprise_oid_default;
+
+const u32_t snmp_zero_dot_zero_values[] = { 0, 0 };
+const struct snmp_obj_id_const_ref snmp_zero_dot_zero = { LWIP_ARRAYSIZE(snmp_zero_dot_zero_values), snmp_zero_dot_zero_values };
+
+
+#if SNMP_LWIP_MIB2
+#include "lwip/apps/snmp_mib2.h"
+static const struct snmp_mib* const default_mibs[] = { &mib2 };
+static u8_t snmp_num_mibs = 1;
+#else
+static const struct snmp_mib* const default_mibs[] = { NULL };
+static u8_t snmp_num_mibs = 0;
+#endif
+
+/* List of known mibs */
+static struct snmp_mib const * const *snmp_mibs = default_mibs;
+
+/**
+ * @ingroup snmp_core
+ * Sets the MIBs to use.
+ * Example: call snmp_set_mibs() as follows:
+ * static const struct snmp_mib *my_snmp_mibs[] = {
+ * &mib2,
+ * &private_mib
+ * };
+ * snmp_set_mibs(my_snmp_mibs, LWIP_ARRAYSIZE(my_snmp_mibs));
+ */
+void
+snmp_set_mibs(const struct snmp_mib **mibs, u8_t num_mibs)
+{
+ LWIP_ASSERT("mibs pointer must be != NULL", (mibs != NULL));
+ LWIP_ASSERT("num_mibs pointer must be != 0", (num_mibs != 0));
+ snmp_mibs = mibs;
+ snmp_num_mibs = num_mibs;
+}
+
+/**
+ * @ingroup snmp_core
+ * '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)
+{
+ if (device_enterprise_oid == NULL) {
+ snmp_device_enterprise_oid = &snmp_device_enterprise_oid_default;
+ } else {
+ snmp_device_enterprise_oid = device_enterprise_oid;
+ }
+}
+
+/**
+ * @ingroup snmp_core
+ * Get 'device enterprise oid'
+ */
+const struct snmp_obj_id* snmp_get_device_enterprise_oid(void)
+{
+ return snmp_device_enterprise_oid;
+}
+
+#if LWIP_IPV4
+/**
+ * Conversion from InetAddressIPv4 oid to lwIP ip4_addr
+ * @param oid points to u32_t ident[4] input
+ * @param ip points to output struct
+ */
+u8_t
+snmp_oid_to_ip4(const u32_t *oid, ip4_addr_t *ip)
+{
+ if ((oid[0] > 0xFF) ||
+ (oid[1] > 0xFF) ||
+ (oid[2] > 0xFF) ||
+ (oid[3] > 0xFF)) {
+ ip4_addr_copy(*ip, *IP4_ADDR_ANY4);
+ return 0;
+ }
+
+ IP4_ADDR(ip, oid[0], oid[1], oid[2], oid[3]);
+ return 1;
+}
+
+/**
+ * Convert ip4_addr to InetAddressIPv4 (no InetAddressType)
+ * @param ip points to input struct
+ * @param oid points to u32_t ident[4] output
+ */
+void
+snmp_ip4_to_oid(const ip4_addr_t *ip, u32_t *oid)
+{
+ oid[0] = ip4_addr1(ip);
+ oid[1] = ip4_addr2(ip);
+ oid[2] = ip4_addr3(ip);
+ oid[3] = ip4_addr4(ip);
+}
+#endif /* LWIP_IPV4 */
+
+#if LWIP_IPV6
+/**
+ * Conversion from InetAddressIPv6 oid to lwIP ip6_addr
+ * @param oid points to u32_t oid[16] input
+ * @param ip points to output struct
+ */
+u8_t
+snmp_oid_to_ip6(const u32_t *oid, ip6_addr_t *ip)
+{
+ if ((oid[0] > 0xFF) ||
+ (oid[1] > 0xFF) ||
+ (oid[2] > 0xFF) ||
+ (oid[3] > 0xFF) ||
+ (oid[4] > 0xFF) ||
+ (oid[5] > 0xFF) ||
+ (oid[6] > 0xFF) ||
+ (oid[7] > 0xFF) ||
+ (oid[8] > 0xFF) ||
+ (oid[9] > 0xFF) ||
+ (oid[10] > 0xFF) ||
+ (oid[11] > 0xFF) ||
+ (oid[12] > 0xFF) ||
+ (oid[13] > 0xFF) ||
+ (oid[14] > 0xFF) ||
+ (oid[15] > 0xFF)) {
+ ip6_addr_set_any(ip);
+ return 0;
+ }
+
+ ip->addr[0] = (oid[0] << 24) | (oid[1] << 16) | (oid[2] << 8) | (oid[3] << 0);
+ ip->addr[1] = (oid[4] << 24) | (oid[5] << 16) | (oid[6] << 8) | (oid[7] << 0);
+ ip->addr[2] = (oid[8] << 24) | (oid[9] << 16) | (oid[10] << 8) | (oid[11] << 0);
+ ip->addr[3] = (oid[12] << 24) | (oid[13] << 16) | (oid[14] << 8) | (oid[15] << 0);
+ return 1;
+}
+
+/**
+ * Convert ip6_addr to InetAddressIPv6 (no InetAddressType)
+ * @param ip points to input struct
+ * @param oid points to u32_t ident[16] output
+ */
+void
+snmp_ip6_to_oid(const ip6_addr_t *ip, u32_t *oid)
+{
+ oid[0] = (ip->addr[0] & 0xFF000000) >> 24;
+ oid[1] = (ip->addr[0] & 0x00FF0000) >> 16;
+ oid[2] = (ip->addr[0] & 0x0000FF00) >> 8;
+ oid[3] = (ip->addr[0] & 0x000000FF) >> 0;
+ oid[4] = (ip->addr[1] & 0xFF000000) >> 24;
+ oid[5] = (ip->addr[1] & 0x00FF0000) >> 16;
+ oid[6] = (ip->addr[1] & 0x0000FF00) >> 8;
+ oid[7] = (ip->addr[1] & 0x000000FF) >> 0;
+ oid[8] = (ip->addr[2] & 0xFF000000) >> 24;
+ oid[9] = (ip->addr[2] & 0x00FF0000) >> 16;
+ oid[10] = (ip->addr[2] & 0x0000FF00) >> 8;
+ oid[11] = (ip->addr[2] & 0x000000FF) >> 0;
+ oid[12] = (ip->addr[3] & 0xFF000000) >> 24;
+ oid[13] = (ip->addr[3] & 0x00FF0000) >> 16;
+ oid[14] = (ip->addr[3] & 0x0000FF00) >> 8;
+ oid[15] = (ip->addr[3] & 0x000000FF) >> 0;
+}
+#endif /* LWIP_IPV6 */
+
+#if LWIP_IPV4 || LWIP_IPV6
+/**
+ * Convert to InetAddressType+InetAddress+InetPortNumber
+ * @param ip IP address
+ * @param port Port
+ * @param oid OID
+ * @return OID length
+ */
+u8_t
+snmp_ip_port_to_oid(const ip_addr_t *ip, u16_t port, u32_t *oid)
+{
+ u8_t idx;
+
+ idx = snmp_ip_to_oid(ip, oid);
+ oid[idx] = port;
+ idx++;
+
+ return idx;
+}
+
+/**
+ * Convert to InetAddressType+InetAddress
+ * @param ip IP address
+ * @param oid OID
+ * @return OID length
+ */
+u8_t
+snmp_ip_to_oid(const ip_addr_t *ip, u32_t *oid)
+{
+ if (IP_IS_ANY_TYPE_VAL(*ip)) {
+ oid[0] = 0; /* any */
+ oid[1] = 0; /* no IP OIDs follow */
+ return 2;
+ } else if (IP_IS_V6(ip)) {
+#if LWIP_IPV6
+ oid[0] = 2; /* ipv6 */
+ oid[1] = 16; /* 16 InetAddressIPv6 OIDs follow */
+ snmp_ip6_to_oid(ip_2_ip6(ip), &oid[2]);
+ return 18;
+#else /* LWIP_IPV6 */
+ return 0;
+#endif /* LWIP_IPV6 */
+ } else {
+#if LWIP_IPV4
+ oid[0] = 1; /* ipv4 */
+ oid[1] = 4; /* 4 InetAddressIPv4 OIDs follow */
+ snmp_ip4_to_oid(ip_2_ip4(ip), &oid[2]);
+ return 6;
+#else /* LWIP_IPV4 */
+ return 0;
+#endif /* LWIP_IPV4 */
+ }
+}
+
+/**
+ * Convert from InetAddressType+InetAddress to ip_addr_t
+ * @param oid OID
+ * @param oid_len OID length
+ * @param ip IP address
+ * @return Parsed OID length
+ */
+u8_t
+snmp_oid_to_ip(const u32_t *oid, u8_t oid_len, ip_addr_t *ip)
+{
+ /* InetAddressType */
+ if (oid_len < 1) {
+ return 0;
+ }
+
+ if (oid[0] == 0) { /* any */
+ /* 1x InetAddressType, 1x OID len */
+ if (oid_len < 2) {
+ return 0;
+ }
+ if (oid[1] != 0) {
+ return 0;
+ }
+
+ memset(ip, 0, sizeof(*ip));
+ IP_SET_TYPE(ip, IPADDR_TYPE_ANY);
+
+ return 2;
+ } else if (oid[0] == 1) { /* ipv4 */
+#if LWIP_IPV4
+ /* 1x InetAddressType, 1x OID len, 4x InetAddressIPv4 */
+ if (oid_len < 6) {
+ return 0;
+ }
+
+ /* 4x ipv4 OID */
+ if (oid[1] != 4) {
+ return 0;
+ }
+
+ IP_SET_TYPE(ip, IPADDR_TYPE_V4);
+ if (!snmp_oid_to_ip4(&oid[2], ip_2_ip4(ip))) {
+ return 0;
+ }
+
+ return 6;
+#else /* LWIP_IPV4 */
+ return 0;
+#endif /* LWIP_IPV4 */
+ } else if (oid[0] == 2) { /* ipv6 */
+#if LWIP_IPV6
+ /* 1x InetAddressType, 1x OID len, 16x InetAddressIPv6 */
+ if (oid_len < 18) {
+ return 0;
+ }
+
+ /* 16x ipv6 OID */
+ if (oid[1] != 16) {
+ return 0;
+ }
+
+ IP_SET_TYPE(ip, IPADDR_TYPE_V6);
+ if (!snmp_oid_to_ip6(&oid[2], ip_2_ip6(ip))) {
+ return 0;
+ }
+
+ return 18;
+#else /* LWIP_IPV6 */
+ return 0;
+#endif /* LWIP_IPV6 */
+ } else { /* unsupported InetAddressType */
+ return 0;
+ }
+}
+
+/**
+ * Convert from InetAddressType+InetAddress+InetPortNumber to ip_addr_t and u16_t
+ * @param oid OID
+ * @param oid_len OID length
+ * @param ip IP address
+ * @param port Port
+ * @return Parsed OID length
+ */
+u8_t
+snmp_oid_to_ip_port(const u32_t *oid, u8_t oid_len, ip_addr_t *ip, u16_t *port)
+{
+ u8_t idx = 0;
+
+ /* InetAddressType + InetAddress */
+ idx += snmp_oid_to_ip(&oid[idx], oid_len-idx, ip);
+ if (idx == 0) {
+ return 0;
+ }
+
+ /* InetPortNumber */
+ if (oid_len < (idx+1)) {
+ return 0;
+ }
+ if (oid[idx] > 0xffff) {
+ return 0;
+ }
+ *port = (u16_t)oid[idx];
+ idx++;
+
+ return idx;
+}
+
+#endif /* LWIP_IPV4 || LWIP_IPV6 */
+
+/**
+ * Assign an OID to struct snmp_obj_id
+ * @param target Assignment target
+ * @param oid OID
+ * @param oid_len OID length
+ */
+void
+snmp_oid_assign(struct snmp_obj_id* target, const u32_t *oid, u8_t oid_len)
+{
+ LWIP_ASSERT("oid_len <= LWIP_SNMP_OBJ_ID_LEN", oid_len <= SNMP_MAX_OBJ_ID_LEN);
+
+ target->len = oid_len;
+
+ if (oid_len > 0) {
+ MEMCPY(target->id, oid, oid_len * sizeof(u32_t));
+ }
+}
+
+/**
+ * Prefix an OID to OID in struct snmp_obj_id
+ * @param target Assignment target to prefix
+ * @param oid OID
+ * @param oid_len OID length
+ */
+void
+snmp_oid_prefix(struct snmp_obj_id* target, const u32_t *oid, u8_t oid_len)
+{
+ LWIP_ASSERT("target->len + oid_len <= LWIP_SNMP_OBJ_ID_LEN", (target->len + oid_len) <= SNMP_MAX_OBJ_ID_LEN);
+
+ if (oid_len > 0) {
+ /* move existing OID to make room at the beginning for OID to insert */
+ int i;
+ for (i = target->len-1; i>=0; i--) {
+ target->id[i + oid_len] = target->id[i];
+ }
+
+ /* paste oid at the beginning */
+ MEMCPY(target->id, oid, oid_len * sizeof(u32_t));
+ }
+}
+
+/**
+ * Combine two OIDs into struct snmp_obj_id
+ * @param target Assignmet target
+ * @param oid1 OID 1
+ * @param oid1_len OID 1 length
+ * @param oid2 OID 2
+ * @param oid2_len OID 2 length
+ */
+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)
+{
+ snmp_oid_assign(target, oid1, oid1_len);
+ snmp_oid_append(target, oid2, oid2_len);
+}
+
+/**
+ * Append OIDs to struct snmp_obj_id
+ * @param target Assignment target to append to
+ * @param oid OID
+ * @param oid_len OID length
+ */
+void
+snmp_oid_append(struct snmp_obj_id* target, const u32_t *oid, u8_t oid_len)
+{
+ LWIP_ASSERT("offset + oid_len <= LWIP_SNMP_OBJ_ID_LEN", (target->len + oid_len) <= SNMP_MAX_OBJ_ID_LEN);
+
+ if (oid_len > 0) {
+ MEMCPY(&target->id[target->len], oid, oid_len * sizeof(u32_t));
+ target->len += oid_len;
+ }
+}
+
+/**
+ * Compare two OIDs
+ * @param oid1 OID 1
+ * @param oid1_len OID 1 length
+ * @param oid2 OID 2
+ * @param oid2_len OID 2 length
+ * @return -1: OID1&lt;OID2 1: OID1 &gt;OID2 0: equal
+ */
+s8_t
+snmp_oid_compare(const u32_t *oid1, u8_t oid1_len, const u32_t *oid2, u8_t oid2_len)
+{
+ u8_t level = 0;
+ LWIP_ASSERT("'oid1' param must not be NULL or 'oid1_len' param be 0!", (oid1 != NULL) || (oid1_len == 0));
+ LWIP_ASSERT("'oid2' param must not be NULL or 'oid2_len' param be 0!", (oid2 != NULL) || (oid2_len == 0));
+
+ while ((level < oid1_len) && (level < oid2_len)) {
+ if (*oid1 < *oid2) {
+ return -1;
+ }
+ if (*oid1 > *oid2) {
+ return 1;
+ }
+
+ level++;
+ oid1++;
+ oid2++;
+ }
+
+ /* common part of both OID's is equal, compare length */
+ if (oid1_len < oid2_len) {
+ return -1;
+ }
+ if (oid1_len > oid2_len) {
+ return 1;
+ }
+
+ /* they are equal */
+ return 0;
+}
+
+
+/**
+ * Check of two OIDs are equal
+ * @param oid1 OID 1
+ * @param oid1_len OID 1 length
+ * @param oid2 OID 2
+ * @param oid2_len OID 2 length
+ * @return 1: equal 0: non-equal
+ */
+u8_t
+snmp_oid_equal(const u32_t *oid1, u8_t oid1_len, const u32_t *oid2, u8_t oid2_len)
+{
+ return (snmp_oid_compare(oid1, oid1_len, oid2, oid2_len) == 0)? 1 : 0;
+}
+
+/**
+ * Convert netif to interface index
+ * @param netif netif
+ * @return index
+ */
+u8_t
+netif_to_num(const struct netif *netif)
+{
+ u8_t result = 0;
+ struct netif *netif_iterator = netif_list;
+
+ while (netif_iterator != NULL) {
+ result++;
+
+ if (netif_iterator == netif) {
+ return result;
+ }
+
+ netif_iterator = netif_iterator->next;
+ }
+
+ LWIP_ASSERT("netif not found in netif_list", 0);
+ return 0;
+}
+
+static const struct snmp_mib*
+snmp_get_mib_from_oid(const u32_t *oid, u8_t oid_len)
+{
+ const u32_t* list_oid;
+ const u32_t* searched_oid;
+ u8_t i, l;
+
+ u8_t max_match_len = 0;
+ const struct snmp_mib* matched_mib = NULL;
+
+ LWIP_ASSERT("'oid' param must not be NULL!", (oid != NULL));
+
+ if (oid_len == 0) {
+ return NULL;
+ }
+
+ for (i = 0; i < snmp_num_mibs; i++) {
+ LWIP_ASSERT("MIB array not initialized correctly", (snmp_mibs[i] != NULL));
+ LWIP_ASSERT("MIB array not initialized correctly - base OID is NULL", (snmp_mibs[i]->base_oid != NULL));
+
+ if (oid_len >= snmp_mibs[i]->base_oid_len) {
+ l = snmp_mibs[i]->base_oid_len;
+ list_oid = snmp_mibs[i]->base_oid;
+ searched_oid = oid;
+
+ while (l > 0) {
+ if (*list_oid != *searched_oid) {
+ break;
+ }
+
+ l--;
+ list_oid++;
+ searched_oid++;
+ }
+
+ if ((l == 0) && (snmp_mibs[i]->base_oid_len > max_match_len)) {
+ max_match_len = snmp_mibs[i]->base_oid_len;
+ matched_mib = snmp_mibs[i];
+ }
+ }
+ }
+
+ return matched_mib;
+}
+
+static const struct snmp_mib*
+snmp_get_next_mib(const u32_t *oid, u8_t oid_len)
+{
+ u8_t i;
+ const struct snmp_mib* next_mib = NULL;
+
+ LWIP_ASSERT("'oid' param must not be NULL!", (oid != NULL));
+
+ if (oid_len == 0) {
+ return NULL;
+ }
+
+ for (i = 0; i < snmp_num_mibs; i++) {
+ if (snmp_mibs[i]->base_oid != NULL) {
+ /* check if mib is located behind starting point */
+ if (snmp_oid_compare(snmp_mibs[i]->base_oid, snmp_mibs[i]->base_oid_len, oid, oid_len) > 0) {
+ if ((next_mib == NULL) ||
+ (snmp_oid_compare(snmp_mibs[i]->base_oid, snmp_mibs[i]->base_oid_len,
+ next_mib->base_oid, next_mib->base_oid_len) < 0)) {
+ next_mib = snmp_mibs[i];
+ }
+ }
+ }
+ }
+
+ return next_mib;
+}
+
+static const struct snmp_mib*
+snmp_get_mib_between(const u32_t *oid1, u8_t oid1_len, const u32_t *oid2, u8_t oid2_len)
+{
+ const struct snmp_mib* next_mib = snmp_get_next_mib(oid1, oid1_len);
+
+ LWIP_ASSERT("'oid2' param must not be NULL!", (oid2 != NULL));
+ LWIP_ASSERT("'oid2_len' param must be greater than 0!", (oid2_len > 0));
+
+ if (next_mib != NULL) {
+ if (snmp_oid_compare(next_mib->base_oid, next_mib->base_oid_len, oid2, oid2_len) < 0) {
+ return next_mib;
+ }
+ }
+
+ return NULL;
+}
+
+u8_t
+snmp_get_node_instance_from_oid(const u32_t *oid, u8_t oid_len, struct snmp_node_instance* node_instance)
+{
+ u8_t result = SNMP_ERR_NOSUCHOBJECT;
+ const struct snmp_mib *mib;
+ const struct snmp_node *mn = NULL;
+
+ mib = snmp_get_mib_from_oid(oid, oid_len);
+ if (mib != NULL) {
+ u8_t oid_instance_len;
+
+ mn = snmp_mib_tree_resolve_exact(mib, oid, oid_len, &oid_instance_len);
+ if ((mn != NULL) && (mn->node_type != SNMP_NODE_TREE)) {
+ /* get instance */
+ const struct snmp_leaf_node* leaf_node = (const struct snmp_leaf_node*)(const void*)mn;
+
+ node_instance->node = mn;
+ snmp_oid_assign(&node_instance->instance_oid, oid + (oid_len - oid_instance_len), oid_instance_len);
+
+ result = leaf_node->get_instance(
+ oid,
+ oid_len - oid_instance_len,
+ node_instance);
+
+#ifdef LWIP_DEBUG
+ if (result == SNMP_ERR_NOERROR) {
+ if (((node_instance->access & SNMP_NODE_INSTANCE_ACCESS_READ) != 0) && (node_instance->get_value == NULL)) {
+ LWIP_DEBUGF(SNMP_DEBUG, ("SNMP inconsistent access: node is readable but no get_value function is specified\n"));
+ }
+ if (((node_instance->access & SNMP_NODE_INSTANCE_ACCESS_WRITE) != 0) && (node_instance->set_value == NULL)) {
+ LWIP_DEBUGF(SNMP_DEBUG, ("SNMP inconsistent access: node is writable but no set_value and/or set_test function is specified\n"));
+ }
+ }
+#endif
+ }
+ }
+
+ return result;
+}
+
+u8_t
+snmp_get_next_node_instance_from_oid(const u32_t *oid, u8_t oid_len, snmp_validate_node_instance_method validate_node_instance_method, void* validate_node_instance_arg, struct snmp_obj_id* node_oid, struct snmp_node_instance* node_instance)
+{
+ const struct snmp_mib *mib;
+ const struct snmp_node *mn = NULL;
+ const u32_t* start_oid = NULL;
+ u8_t start_oid_len = 0;
+
+ /* resolve target MIB from passed OID */
+ mib = snmp_get_mib_from_oid(oid, oid_len);
+ if (mib == NULL) {
+ /* passed OID does not reference any known MIB, start at the next closest MIB */
+ mib = snmp_get_next_mib(oid, oid_len);
+
+ if (mib != NULL) {
+ start_oid = mib->base_oid;
+ start_oid_len = mib->base_oid_len;
+ }
+ } else {
+ start_oid = oid;
+ start_oid_len = oid_len;
+ }
+
+ /* resolve target node from MIB, skip to next MIB if no suitable node is found in current MIB */
+ while ((mib != NULL) && (mn == NULL)) {
+ u8_t oid_instance_len;
+
+ /* check if OID directly references a node inside current MIB, in this case we have to ask this node for the next instance */
+ mn = snmp_mib_tree_resolve_exact(mib, start_oid, start_oid_len, &oid_instance_len);
+ if (mn != NULL) {
+ snmp_oid_assign(node_oid, start_oid, start_oid_len - oid_instance_len); /* set oid to node */
+ snmp_oid_assign(&node_instance->instance_oid, start_oid + (start_oid_len - oid_instance_len), oid_instance_len); /* set (relative) instance oid */
+ } else {
+ /* OID does not reference a node, search for the next closest node inside MIB; set instance_oid.len to zero because we want the first instance of this node */
+ mn = snmp_mib_tree_resolve_next(mib, start_oid, start_oid_len, node_oid);
+ node_instance->instance_oid.len = 0;
+ }
+
+ /* validate the node; if the node has no further instance or the returned instance is invalid, search for the next in MIB and validate again */
+ node_instance->node = mn;
+ while (mn != NULL) {
+ u8_t result;
+
+ /* clear fields which may have values from previous loops */
+ node_instance->asn1_type = 0;
+ node_instance->access = SNMP_NODE_INSTANCE_NOT_ACCESSIBLE;
+ node_instance->get_value = NULL;
+ node_instance->set_test = NULL;
+ node_instance->set_value = NULL;
+ node_instance->release_instance = NULL;
+ node_instance->reference.ptr = NULL;
+ node_instance->reference_len = 0;
+
+ result = ((const struct snmp_leaf_node*)(const void*)mn)->get_next_instance(
+ node_oid->id,
+ node_oid->len,
+ node_instance);
+
+ if (result == SNMP_ERR_NOERROR) {
+#ifdef LWIP_DEBUG
+ if (((node_instance->access & SNMP_NODE_INSTANCE_ACCESS_READ) != 0) && (node_instance->get_value == NULL)) {
+ LWIP_DEBUGF(SNMP_DEBUG, ("SNMP inconsistent access: node is readable but no get_value function is specified\n"));
+ }
+ if (((node_instance->access & SNMP_NODE_INSTANCE_ACCESS_WRITE) != 0) && (node_instance->set_value == NULL)) {
+ LWIP_DEBUGF(SNMP_DEBUG, ("SNMP inconsistent access: node is writable but no set_value function is specified\n"));
+ }
+#endif
+
+ /* validate node because the node may be not accessible for example (but let the caller decide what is valid */
+ if ((validate_node_instance_method == NULL) ||
+ (validate_node_instance_method(node_instance, validate_node_instance_arg) == SNMP_ERR_NOERROR)) {
+ /* node_oid "returns" the full result OID (including the instance part) */
+ snmp_oid_append(node_oid, node_instance->instance_oid.id, node_instance->instance_oid.len);
+ break;
+ }
+
+ if (node_instance->release_instance != NULL) {
+ node_instance->release_instance(node_instance);
+ }
+ /*
+ the instance itself is not valid, ask for next instance from same node.
+ we don't have to change any variables because node_instance->instance_oid is used as input (starting point)
+ as well as output (resulting next OID), so we have to simply call get_next_instance method again
+ */
+ } else {
+ if (node_instance->release_instance != NULL) {
+ node_instance->release_instance(node_instance);
+ }
+
+ /* the node has no further instance, skip to next node */
+ mn = snmp_mib_tree_resolve_next(mib, node_oid->id, node_oid->len, &node_instance->instance_oid); /* misuse node_instance->instance_oid as tmp buffer */
+ if (mn != NULL) {
+ /* prepare for next loop */
+ snmp_oid_assign(node_oid, node_instance->instance_oid.id, node_instance->instance_oid.len);
+ node_instance->instance_oid.len = 0;
+ node_instance->node = mn;
+ }
+ }
+ }
+
+ if (mn != NULL) {
+ /*
+ we found a suitable next node,
+ now we have to check if a inner MIB is located between the searched OID and the resulting OID.
+ this is possible because MIB's may be located anywhere in the global tree, that means also in
+ the subtree of another MIB (e.g. if searched OID is .2 and resulting OID is .4, then another
+ MIB having .3 as root node may exist)
+ */
+ const struct snmp_mib *intermediate_mib;
+ intermediate_mib = snmp_get_mib_between(start_oid, start_oid_len, node_oid->id, node_oid->len);
+
+ if (intermediate_mib != NULL) {
+ /* search for first node inside intermediate mib in next loop */
+ if (node_instance->release_instance != NULL) {
+ node_instance->release_instance(node_instance);
+ }
+
+ mn = NULL;
+ mib = intermediate_mib;
+ start_oid = mib->base_oid;
+ start_oid_len = mib->base_oid_len;
+ }
+ /* else { we found out target node } */
+ } else {
+ /*
+ there is no further (suitable) node inside this MIB, search for the next MIB with following priority
+ 1. search for inner MIB's (whose root is located inside tree of current MIB)
+ 2. search for surrouding MIB's (where the current MIB is the inner MIB) and continue there if any
+ 3. take the next closest MIB (not being related to the current MIB)
+ */
+ const struct snmp_mib *next_mib;
+ next_mib = snmp_get_next_mib(start_oid, start_oid_len); /* returns MIB's related to point 1 and 3 */
+
+ /* is the found MIB an inner MIB? (point 1) */
+ if ((next_mib != NULL) && (next_mib->base_oid_len > mib->base_oid_len) &&
+ (snmp_oid_compare(next_mib->base_oid, mib->base_oid_len, mib->base_oid, mib->base_oid_len) == 0)) {
+ /* yes it is -> continue at inner MIB */
+ mib = next_mib;
+ start_oid = mib->base_oid;
+ start_oid_len = mib->base_oid_len;
+ } else {
+ /* check if there is a surrounding mib where to continue (point 2) (only possible if OID length > 1) */
+ if (mib->base_oid_len > 1) {
+ mib = snmp_get_mib_from_oid(mib->base_oid, mib->base_oid_len - 1);
+
+ if (mib == NULL) {
+ /* no surrounding mib, use next mib encountered above (point 3) */
+ mib = next_mib;
+
+ if (mib != NULL) {
+ start_oid = mib->base_oid;
+ start_oid_len = mib->base_oid_len;
+ }
+ }
+ /* else { start_oid stays the same because we want to continue from current offset in surrounding mib (point 2) } */
+ }
+ }
+ }
+ }
+
+ if (mib == NULL) {
+ /* loop is only left when mib == null (error) or mib_node != NULL (success) */
+ return SNMP_ERR_ENDOFMIBVIEW;
+ }
+
+ return SNMP_ERR_NOERROR;
+}
+
+/**
+ * Searches tree for the supplied object identifier.
+ *
+ */
+const struct snmp_node *
+snmp_mib_tree_resolve_exact(const struct snmp_mib *mib, const u32_t *oid, u8_t oid_len, u8_t* oid_instance_len)
+{
+ const struct snmp_node* const* node = &mib->root_node;
+ u8_t oid_offset = mib->base_oid_len;
+
+ while ((oid_offset < oid_len) && ((*node)->node_type == SNMP_NODE_TREE)) {
+ /* search for matching sub node */
+ u32_t subnode_oid = *(oid + oid_offset);
+
+ u32_t i = (*(const struct snmp_tree_node* const*)node)->subnode_count;
+ node = (*(const struct snmp_tree_node* const*)node)->subnodes;
+ while ((i > 0) && ((*node)->oid != subnode_oid)) {
+ node++;
+ i--;
+ }
+
+ if (i == 0) {
+ /* no matching subnode found */
+ return NULL;
+ }
+
+ oid_offset++;
+ }
+
+ if ((*node)->node_type != SNMP_NODE_TREE) {
+ /* we found a leaf node */
+ *oid_instance_len = oid_len - oid_offset;
+ return (*node);
+ }
+
+ return NULL;
+}
+
+const struct snmp_node*
+snmp_mib_tree_resolve_next(const struct snmp_mib *mib, const u32_t *oid, u8_t oid_len, struct snmp_obj_id* oidret)
+{
+ u8_t oid_offset = mib->base_oid_len;
+ const struct snmp_node* const* node;
+ const struct snmp_tree_node* node_stack[SNMP_MAX_OBJ_ID_LEN];
+ s32_t nsi = 0; /* NodeStackIndex */
+ u32_t subnode_oid;
+
+ if (mib->root_node->node_type != SNMP_NODE_TREE) {
+ /* a next operation on a mib with only a leaf node will always return NULL because there is no other node */
+ return NULL;
+ }
+
+ /* first build node stack related to passed oid (as far as possible), then go backwards to determine the next node */
+ node_stack[nsi] = (const struct snmp_tree_node*)(const void*)mib->root_node;
+ while (oid_offset < oid_len) {
+ /* search for matching sub node */
+ u32_t i = node_stack[nsi]->subnode_count;
+ node = node_stack[nsi]->subnodes;
+
+ subnode_oid = *(oid + oid_offset);
+
+ while ((i > 0) && ((*node)->oid != subnode_oid)) {
+ node++;
+ i--;
+ }
+
+ if ((i == 0) || ((*node)->node_type != SNMP_NODE_TREE)) {
+ /* no (matching) tree-subnode found */
+ break;
+ }
+ nsi++;
+ node_stack[nsi] = (const struct snmp_tree_node*)(const void*)(*node);
+
+ oid_offset++;
+ }
+
+
+ if (oid_offset >= oid_len) {
+ /* passed oid references a tree node -> return first useable sub node of it */
+ subnode_oid = 0;
+ } else {
+ subnode_oid = *(oid + oid_offset) + 1;
+ }
+
+ while (nsi >= 0) {
+ const struct snmp_node* subnode = NULL;
+
+ /* find next node on current level */
+ s32_t i = node_stack[nsi]->subnode_count;
+ node = node_stack[nsi]->subnodes;
+ while (i > 0) {
+ if ((*node)->oid == subnode_oid) {
+ subnode = *node;
+ break;
+ } else if (((*node)->oid > subnode_oid) && ((subnode == NULL) || ((*node)->oid < subnode->oid))) {
+ subnode = *node;
+ }
+
+ node++;
+ i--;
+ }
+
+ if (subnode == NULL) {
+ /* no further node found on this level, go one level up and start searching with index of current node*/
+ subnode_oid = node_stack[nsi]->node.oid + 1;
+ nsi--;
+ } else {
+ if (subnode->node_type == SNMP_NODE_TREE) {
+ /* next is a tree node, go into it and start searching */
+ nsi++;
+ node_stack[nsi] = (const struct snmp_tree_node*)(const void*)subnode;
+ subnode_oid = 0;
+ } else {
+ /* we found a leaf node -> fill oidret and return it */
+ snmp_oid_assign(oidret, mib->base_oid, mib->base_oid_len);
+ i = 1;
+ while (i <= nsi) {
+ oidret->id[oidret->len] = node_stack[i]->node.oid;
+ oidret->len++;
+ i++;
+ }
+
+ oidret->id[oidret->len] = subnode->oid;
+ oidret->len++;
+
+ return subnode;
+ }
+ }
+ }
+
+ return NULL;
+}
+
+/** 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)
+{
+ state->start_oid = start_oid;
+ state->start_oid_len = start_oid_len;
+ state->next_oid = next_oid_buf;
+ state->next_oid_len = 0;
+ state->next_oid_max_len = next_oid_max_len;
+ state->status = SNMP_NEXT_OID_STATUS_NO_MATCH;
+}
+
+/** 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)
+{
+ if (state->status != SNMP_NEXT_OID_STATUS_BUF_TO_SMALL) {
+ u8_t start_oid_len = (oid_len < state->start_oid_len) ? oid_len : state->start_oid_len;
+
+ /* check passed OID is located behind start offset */
+ if (snmp_oid_compare(oid, oid_len, state->start_oid, start_oid_len) >= 0) {
+ /* check if new oid is located closer to start oid than current closest oid */
+ if ((state->status == SNMP_NEXT_OID_STATUS_NO_MATCH) ||
+ (snmp_oid_compare(oid, oid_len, state->next_oid, state->next_oid_len) < 0)) {
+ return 1;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/** 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)
+{
+ /* do not overwrite a fail result */
+ if (state->status != SNMP_NEXT_OID_STATUS_BUF_TO_SMALL) {
+ /* check passed OID is located behind start offset */
+ if (snmp_oid_compare(oid, oid_len, state->start_oid, state->start_oid_len) > 0) {
+ /* check if new oid is located closer to start oid than current closest oid */
+ if ((state->status == SNMP_NEXT_OID_STATUS_NO_MATCH) ||
+ (snmp_oid_compare(oid, oid_len, state->next_oid, state->next_oid_len) < 0)) {
+ if (oid_len <= state->next_oid_max_len) {
+ MEMCPY(state->next_oid, oid, oid_len * sizeof(u32_t));
+ state->next_oid_len = oid_len;
+ state->status = SNMP_NEXT_OID_STATUS_SUCCESS;
+ state->reference = reference;
+ return 1;
+ } else {
+ state->status = SNMP_NEXT_OID_STATUS_BUF_TO_SMALL;
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+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)
+{
+ u8_t i;
+
+ if (oid_len != oid_ranges_len) {
+ return 0;
+ }
+
+ for (i = 0; i < oid_ranges_len; i++) {
+ if ((oid_in[i] < oid_ranges[i].min) || (oid_in[i] > oid_ranges[i].max)) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+snmp_err_t
+snmp_set_test_ok(struct snmp_node_instance* instance, u16_t value_len, void* value)
+{
+ LWIP_UNUSED_ARG(instance);
+ LWIP_UNUSED_ARG(value_len);
+ LWIP_UNUSED_ARG(value);
+
+ return SNMP_ERR_NOERROR;
+}
+
+/**
+ * Decodes BITS pseudotype value from ASN.1 OctetString.
+ *
+ * @note Because BITS pseudo type is encoded as OCTET STRING, it cannot directly
+ * be encoded/decoded by the agent. Instead call this function as required from
+ * get/test/set methods.
+ *
+ * @param buf points to a buffer holding the ASN1 octet string
+ * @param buf_len length of octet string
+ * @param bit_value decoded Bit value with Bit0 == LSB
+ * @return ERR_OK if successful, ERR_ARG if bit value contains more than 32 bit
+ */
+err_t
+snmp_decode_bits(const u8_t *buf, u32_t buf_len, u32_t *bit_value)
+{
+ u8_t b;
+ u8_t bits_processed = 0;
+ *bit_value = 0;
+
+ while (buf_len > 0) {
+ /* any bit set in this byte? */
+ if (*buf != 0x00) {
+ if (bits_processed >= 32) {
+ /* accept more than 4 bytes, but only when no bits are set */
+ return ERR_VAL;
+ }
+
+ b = *buf;
+ do {
+ if (b & 0x80) {
+ *bit_value |= (1 << bits_processed);
+ }
+ bits_processed++;
+ b <<= 1;
+ }
+ while ((bits_processed & 0x07) != 0); /* &0x07 -> % 8 */
+ } else {
+ bits_processed += 8;
+ }
+
+ buf_len--;
+ buf++;
+ }
+
+ return ERR_OK;
+}
+
+err_t
+snmp_decode_truthvalue(const s32_t *asn1_value, u8_t *bool_value)
+{
+ /* defined by RFC1443:
+ TruthValue ::= TEXTUAL-CONVENTION
+ STATUS current
+ DESCRIPTION
+ "Represents a boolean value."
+ SYNTAX INTEGER { true(1), false(2) }
+ */
+
+ if ((asn1_value == NULL) || (bool_value == NULL)) {
+ return ERR_ARG;
+ }
+
+ if (*asn1_value == 1) {
+ *bool_value = 1;
+ } else if (*asn1_value == 2) {
+ *bool_value = 0;
+ } else {
+ return ERR_VAL;
+ }
+
+ return ERR_OK;
+}
+
+/**
+ * Encodes BITS pseudotype value into ASN.1 OctetString.
+ *
+ * @note Because BITS pseudo type is encoded as OCTET STRING, it cannot directly
+ * be encoded/decoded by the agent. Instead call this function as required from
+ * get/test/set methods.
+ *
+ * @param buf points to a buffer where the resulting ASN1 octet string is stored to
+ * @param buf_len max length of the bufffer
+ * @param bit_value Bit value to encode with Bit0 == LSB
+ * @param bit_count Number of possible bits for the bit value (according to rfc we have to send all bits independant from their truth value)
+ * @return number of bytes used from buffer to store the resulting OctetString
+ */
+u8_t
+snmp_encode_bits(u8_t *buf, u32_t buf_len, u32_t bit_value, u8_t bit_count)
+{
+ u8_t len = 0;
+ u8_t min_bytes = (bit_count + 7) >> 3; /* >>3 -> / 8 */
+
+ while ((buf_len > 0) && (bit_value != 0x00)) {
+ s8_t i = 7;
+ *buf = 0x00;
+ while (i >= 0) {
+ if (bit_value & 0x01) {
+ *buf |= 0x01;
+ }
+
+ if (i > 0) {
+ *buf <<= 1;
+ }
+
+ bit_value >>= 1;
+ i--;
+ }
+
+ buf++;
+ buf_len--;
+ len++;
+ }
+
+ if (len < min_bytes) {
+ buf += len;
+ buf_len -= len;
+
+ while ((len < min_bytes) && (buf_len > 0)) {
+ *buf = 0x00;
+ buf++;
+ buf_len--;
+ len++;
+ }
+ }
+
+ return len;
+}
+
+u8_t
+snmp_encode_truthvalue(s32_t *asn1_value, u32_t bool_value)
+{
+ /* defined by RFC1443:
+ TruthValue ::= TEXTUAL-CONVENTION
+ STATUS current
+ DESCRIPTION
+ "Represents a boolean value."
+ SYNTAX INTEGER { true(1), false(2) }
+ */
+
+ if (asn1_value == NULL) {
+ return 0;
+ }
+
+ if (bool_value) {
+ *asn1_value = 1; /* defined by RFC1443 */
+ } else {
+ *asn1_value = 2; /* defined by RFC1443 */
+ }
+
+ return sizeof(s32_t);
+}
+
+#endif /* LWIP_SNMP */