snmp_msg.h

00001 /**
00002  * @file
00003  * SNMP Agent message handling structures.
00004  */
00005 
00006 /*
00007  * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
00008  * All rights reserved.
00009  *
00010  * Redistribution and use in source and binary forms, with or without modification,
00011  * are permitted provided that the following conditions are met:
00012  *
00013  * 1. Redistributions of source code must retain the above copyright notice,
00014  *    this list of conditions and the following disclaimer.
00015  * 2. Redistributions in binary form must reproduce the above copyright notice,
00016  *    this list of conditions and the following disclaimer in the documentation
00017  *    and/or other materials provided with the distribution.
00018  * 3. The name of the author may not be used to endorse or promote products
00019  *    derived from this software without specific prior written permission.
00020  *
00021  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00022  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00023  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00024  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00025  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00026  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00027  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00028  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00029  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00030  * OF SUCH DAMAGE.
00031  *
00032  * Author: Christiaan Simons <christiaan.simons@axon.tv>
00033  */
00034 
00035 #ifndef __LWIP_SNMP_MSG_H__
00036 #define __LWIP_SNMP_MSG_H__
00037 
00038 #include "lwip/opt.h"
00039 #include "lwip/snmp.h"
00040 #include "lwip/snmp_structs.h"
00041 
00042 #if SNMP_PRIVATE_MIB
00043 #include "private_mib.h"
00044 #endif
00045 
00046 #ifdef __cplusplus
00047 extern "C" {
00048 #endif
00049 
00050 /* The listen port of the SNMP agent. Clients have to make their requests to
00051    this port. Most standard clients won't work if you change this! */
00052 #ifndef SNMP_IN_PORT
00053 #define SNMP_IN_PORT 161
00054 #endif
00055 /* The remote port the SNMP agent sends traps to. Most standard trap sinks won't
00056    work if you change this! */
00057 #ifndef SNMP_TRAP_PORT
00058 #define SNMP_TRAP_PORT 162
00059 #endif
00060 
00061 #define SNMP_ES_NOERROR 0
00062 #define SNMP_ES_TOOBIG 1
00063 #define SNMP_ES_NOSUCHNAME 2
00064 #define SNMP_ES_BADVALUE 3
00065 #define SNMP_ES_READONLY 4
00066 #define SNMP_ES_GENERROR 5
00067 
00068 #define SNMP_GENTRAP_COLDSTART 0
00069 #define SNMP_GENTRAP_WARMSTART 1
00070 #define SNMP_GENTRAP_AUTHFAIL 4
00071 #define SNMP_GENTRAP_ENTERPRISESPC 6
00072 
00073 struct snmp_varbind
00074 {
00075   /* next pointer, NULL for last in list */
00076   struct snmp_varbind *next;
00077   /* previous pointer, NULL for first in list */
00078   struct snmp_varbind *prev;
00079 
00080   /* object identifier length (in s32_t) */
00081   u8_t ident_len;
00082   /* object identifier array */
00083   s32_t *ident;
00084 
00085   /* object value ASN1 type */
00086   u8_t value_type;
00087   /* object value length (in u8_t) */
00088   u8_t value_len;
00089   /* object value */
00090   void *value;
00091 
00092   /* encoding varbind seq length length */
00093   u8_t seqlenlen;
00094   /* encoding object identifier length length */
00095   u8_t olenlen;
00096   /* encoding object value length length */
00097   u8_t vlenlen;
00098   /* encoding varbind seq length */
00099   u16_t seqlen;
00100   /* encoding object identifier length */
00101   u16_t olen;
00102   /* encoding object value length */
00103   u16_t vlen;
00104 };
00105 
00106 struct snmp_varbind_root
00107 {
00108   struct snmp_varbind *head;
00109   struct snmp_varbind *tail;
00110   /* number of variable bindings in list */
00111   u8_t count;
00112   /* encoding varbind-list seq length length */
00113   u8_t seqlenlen;
00114   /* encoding varbind-list seq length */
00115   u16_t seqlen;
00116 };
00117 
00118 /** output response message header length fields */
00119 struct snmp_resp_header_lengths
00120 {
00121   /* encoding error-index length length */
00122   u8_t erridxlenlen;
00123   /* encoding error-status length length */
00124   u8_t errstatlenlen;
00125   /* encoding request id length length */
00126   u8_t ridlenlen;
00127   /* encoding pdu length length */
00128   u8_t pdulenlen;
00129   /* encoding community length length */
00130   u8_t comlenlen;
00131   /* encoding version length length */
00132   u8_t verlenlen;
00133   /* encoding sequence length length */
00134   u8_t seqlenlen;
00135 
00136   /* encoding error-index length */
00137   u16_t erridxlen;
00138   /* encoding error-status length */
00139   u16_t errstatlen;
00140   /* encoding request id length */
00141   u16_t ridlen;
00142   /* encoding pdu length */
00143   u16_t pdulen;
00144   /* encoding community length */
00145   u16_t comlen;
00146   /* encoding version length */
00147   u16_t verlen;
00148   /* encoding sequence length */
00149   u16_t seqlen;
00150 };
00151 
00152 /** output response message header length fields */
00153 struct snmp_trap_header_lengths
00154 {
00155   /* encoding timestamp length length */
00156   u8_t tslenlen;
00157   /* encoding specific-trap length length */
00158   u8_t strplenlen;
00159   /* encoding generic-trap length length */
00160   u8_t gtrplenlen;
00161   /* encoding agent-addr length length */
00162   u8_t aaddrlenlen;
00163   /* encoding enterprise-id length length */
00164   u8_t eidlenlen;
00165   /* encoding pdu length length */
00166   u8_t pdulenlen;
00167   /* encoding community length length */
00168   u8_t comlenlen;
00169   /* encoding version length length */
00170   u8_t verlenlen;
00171   /* encoding sequence length length */
00172   u8_t seqlenlen;
00173 
00174   /* encoding timestamp length */
00175   u16_t tslen;
00176   /* encoding specific-trap length */
00177   u16_t strplen;
00178   /* encoding generic-trap length */
00179   u16_t gtrplen;
00180   /* encoding agent-addr length */
00181   u16_t aaddrlen;
00182   /* encoding enterprise-id length */
00183   u16_t eidlen;
00184   /* encoding pdu length */
00185   u16_t pdulen;
00186   /* encoding community length */
00187   u16_t comlen;
00188   /* encoding version length */
00189   u16_t verlen;
00190   /* encoding sequence length */
00191   u16_t seqlen;
00192 };
00193 
00194 /* Accepting new SNMP messages. */
00195 #define SNMP_MSG_EMPTY                 0
00196 /* Search for matching object for variable binding. */
00197 #define SNMP_MSG_SEARCH_OBJ            1
00198 /* Perform SNMP operation on in-memory object.
00199    Pass-through states, for symmetry only. */
00200 #define SNMP_MSG_INTERNAL_GET_OBJDEF   2
00201 #define SNMP_MSG_INTERNAL_GET_VALUE    3
00202 #define SNMP_MSG_INTERNAL_SET_TEST     4
00203 #define SNMP_MSG_INTERNAL_GET_OBJDEF_S 5
00204 #define SNMP_MSG_INTERNAL_SET_VALUE    6
00205 /* Perform SNMP operation on object located externally.
00206    In theory this could be used for building a proxy agent.
00207    Practical use is for an enterprise spc. app. gateway. */
00208 #define SNMP_MSG_EXTERNAL_GET_OBJDEF   7
00209 #define SNMP_MSG_EXTERNAL_GET_VALUE    8
00210 #define SNMP_MSG_EXTERNAL_SET_TEST     9
00211 #define SNMP_MSG_EXTERNAL_GET_OBJDEF_S 10
00212 #define SNMP_MSG_EXTERNAL_SET_VALUE    11
00213 
00214 #define SNMP_COMMUNITY_STR_LEN 64
00215 struct snmp_msg_pstat
00216 {
00217   /* lwIP local port (161) binding */
00218   struct udp_pcb *pcb;
00219   /* source IP address */
00220   struct ip_addr sip;
00221   /* source UDP port */
00222   u16_t sp;
00223   /* request type */
00224   u8_t rt;
00225   /* request ID */
00226   s32_t rid;
00227   /* error status */
00228   s32_t error_status;
00229   /* error index */
00230   s32_t error_index;
00231   /* community name (zero terminated) */
00232   u8_t community[SNMP_COMMUNITY_STR_LEN + 1];
00233   /* community string length (exclusive zero term) */
00234   u8_t com_strlen;
00235   /* one out of MSG_EMPTY, MSG_DEMUX, MSG_INTERNAL, MSG_EXTERNAL_x */
00236   u8_t state;
00237   /* saved arguments for MSG_EXTERNAL_x */
00238   struct mib_external_node *ext_mib_node;
00239   struct snmp_name_ptr ext_name_ptr;
00240   struct obj_def ext_object_def;
00241   struct snmp_obj_id ext_oid;
00242   /* index into input variable binding list */
00243   u8_t vb_idx;
00244   /* ptr into input variable binding list */
00245   struct snmp_varbind *vb_ptr;
00246   /* list of variable bindings from input */
00247   struct snmp_varbind_root invb;
00248   /* list of variable bindings to output */
00249   struct snmp_varbind_root outvb;
00250   /* output response lengths used in ASN encoding */
00251   struct snmp_resp_header_lengths rhl;
00252 };
00253 
00254 struct snmp_msg_trap
00255 {
00256   /* lwIP local port (161) binding */
00257   struct udp_pcb *pcb;
00258   /* destination IP address in network order */
00259   struct ip_addr dip;
00260 
00261   /* source enterprise ID (sysObjectID) */
00262   struct snmp_obj_id *enterprise;
00263   /* source IP address, raw network order format */
00264   u8_t sip_raw[4];
00265   /* generic trap code */
00266   u32_t gen_trap;
00267   /* specific trap code */
00268   u32_t spc_trap;
00269   /* timestamp */
00270   u32_t ts;
00271   /* list of variable bindings to output */
00272   struct snmp_varbind_root outvb;
00273   /* output trap lengths used in ASN encoding */
00274   struct snmp_trap_header_lengths thl;
00275 };
00276 
00277 /** Agent Version constant, 0 = v1 oddity */
00278 extern const s32_t snmp_version;
00279 /** Agent default "public" community string */
00280 extern const char snmp_publiccommunity[7];
00281 
00282 extern struct snmp_msg_trap trap_msg;
00283 
00284 /** Agent setup, start listening to port 161. */
00285 void snmp_init(void);
00286 void snmp_trap_dst_enable(u8_t dst_idx, u8_t enable);
00287 void snmp_trap_dst_ip_set(u8_t dst_idx, struct ip_addr *dst);
00288 
00289 /** Varbind-list functions. */
00290 struct snmp_varbind* snmp_varbind_alloc(struct snmp_obj_id *oid, u8_t type, u8_t len);
00291 void snmp_varbind_free(struct snmp_varbind *vb);
00292 void snmp_varbind_list_free(struct snmp_varbind_root *root);
00293 void snmp_varbind_tail_add(struct snmp_varbind_root *root, struct snmp_varbind *vb);
00294 struct snmp_varbind* snmp_varbind_tail_remove(struct snmp_varbind_root *root);
00295 
00296 /** Handle an internal (recv) or external (private response) event. */
00297 void snmp_msg_event(u8_t request_id);
00298 err_t snmp_send_response(struct snmp_msg_pstat *m_stat);
00299 err_t snmp_send_trap(s8_t generic_trap, struct snmp_obj_id *eoid, s32_t specific_trap);
00300 void snmp_coldstart_trap(void);
00301 void snmp_authfail_trap(void);
00302 
00303 #ifdef __cplusplus
00304 }
00305 #endif
00306 
00307 #endif /* __LWIP_SNMP_MSG_H__ */