msg_out.c

00001 /**
00002  * @file
00003  * SNMP output message processing (RFC1157).
00004  *
00005  * Output responses and traps are build in two passes:
00006  *
00007  * Pass 0: iterate over the output message backwards to determine encoding lengths
00008  * Pass 1: the actual forward encoding of internal form into ASN1
00009  *
00010  * The single-pass encoding method described by Comer & Stevens
00011  * requires extra buffer space and copying for reversal of the packet.
00012  * The buffer requirement can be prohibitively large for big payloads
00013  * (>= 484) therefore we use the two encoding passes.
00014  */
00015 
00016 /*
00017  * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
00018  * All rights reserved.
00019  *
00020  * Redistribution and use in source and binary forms, with or without modification,
00021  * are permitted provided that the following conditions are met:
00022  *
00023  * 1. Redistributions of source code must retain the above copyright notice,
00024  *    this list of conditions and the following disclaimer.
00025  * 2. Redistributions in binary form must reproduce the above copyright notice,
00026  *    this list of conditions and the following disclaimer in the documentation
00027  *    and/or other materials provided with the distribution.
00028  * 3. The name of the author may not be used to endorse or promote products
00029  *    derived from this software without specific prior written permission.
00030  *
00031  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00032  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00033  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00034  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00035  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00036  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00037  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00038  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00039  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00040  * OF SUCH DAMAGE.
00041  *
00042  * Author: Christiaan Simons <christiaan.simons@axon.tv>
00043  */
00044 
00045 #include "lwip/opt.h"
00046 
00047 #if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */
00048 
00049 #include "lwip/udp.h"
00050 #include "lwip/netif.h"
00051 #include "lwip/snmp.h"
00052 #include "lwip/snmp_asn1.h"
00053 #include "lwip/snmp_msg.h"
00054 
00055 struct snmp_trap_dst
00056 {
00057   /* destination IP address in network order */
00058   ip_addr_t dip;
00059   /* set to 0 when disabled, >0 when enabled */
00060   u8_t enable;
00061 };
00062 struct snmp_trap_dst trap_dst[SNMP_TRAP_DESTINATIONS];
00063 
00064 /** TRAP message structure */
00065 struct snmp_msg_trap trap_msg;
00066 
00067 static u16_t snmp_resp_header_sum(struct snmp_msg_pstat *m_stat, u16_t vb_len);
00068 static u16_t snmp_trap_header_sum(struct snmp_msg_trap *m_trap, u16_t vb_len);
00069 static u16_t snmp_varbind_list_sum(struct snmp_varbind_root *root);
00070 
00071 static u16_t snmp_resp_header_enc(struct snmp_msg_pstat *m_stat, struct pbuf *p);
00072 static u16_t snmp_trap_header_enc(struct snmp_msg_trap *m_trap, struct pbuf *p);
00073 static u16_t snmp_varbind_list_enc(struct snmp_varbind_root *root, struct pbuf *p, u16_t ofs);
00074 
00075 /**
00076  * Sets enable switch for this trap destination.
00077  * @param dst_idx index in 0 .. SNMP_TRAP_DESTINATIONS-1
00078  * @param enable switch if 0 destination is disabled >0 enabled.
00079  */
00080 void
00081 snmp_trap_dst_enable(u8_t dst_idx, u8_t enable)
00082 {
00083   if (dst_idx < SNMP_TRAP_DESTINATIONS)
00084   {
00085     trap_dst[dst_idx].enable = enable;
00086   }
00087 }
00088 
00089 /**
00090  * Sets IPv4 address for this trap destination.
00091  * @param dst_idx index in 0 .. SNMP_TRAP_DESTINATIONS-1
00092  * @param dst IPv4 address in host order.
00093  */
00094 void
00095 snmp_trap_dst_ip_set(u8_t dst_idx, ip_addr_t *dst)
00096 {
00097   if (dst_idx < SNMP_TRAP_DESTINATIONS)
00098   {
00099     ip_addr_set_hton(&trap_dst[dst_idx].dip, dst);
00100   }
00101 }
00102 
00103 /**
00104  * Sends a 'getresponse' message to the request originator.
00105  *
00106  * @param m_stat points to the current message request state source
00107  * @return ERR_OK when success, ERR_MEM if we're out of memory
00108  *
00109  * @note the caller is responsible for filling in outvb in the m_stat
00110  * and provide error-status and index (except for tooBig errors) ...
00111  */
00112 err_t
00113 snmp_send_response(struct snmp_msg_pstat *m_stat)
00114 {
00115   struct snmp_varbind_root emptyvb = {NULL, NULL, 0, 0, 0};
00116   struct pbuf *p;
00117   u16_t tot_len;
00118   err_t err;
00119 
00120   /* pass 0, calculate length fields */
00121   tot_len = snmp_varbind_list_sum(&m_stat->outvb);
00122   tot_len = snmp_resp_header_sum(m_stat, tot_len);
00123 
00124   /* try allocating pbuf(s) for complete response */
00125   p = pbuf_alloc(PBUF_TRANSPORT, tot_len, PBUF_POOL);
00126   if (p == NULL)
00127   {
00128     LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_snd_response() tooBig\n"));
00129 
00130     /* can't construct reply, return error-status tooBig */
00131     m_stat->error_status = SNMP_ES_TOOBIG;
00132     m_stat->error_index = 0;
00133     /* pass 0, recalculate lengths, for empty varbind-list */
00134     tot_len = snmp_varbind_list_sum(&emptyvb);
00135     tot_len = snmp_resp_header_sum(m_stat, tot_len);
00136     /* retry allocation once for header and empty varbind-list */
00137     p = pbuf_alloc(PBUF_TRANSPORT, tot_len, PBUF_POOL);
00138   }
00139   if (p != NULL)
00140   {
00141     /* first pbuf alloc try or retry alloc success */
00142     u16_t ofs;
00143 
00144     LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_snd_response() p != NULL\n"));
00145 
00146     /* pass 1, size error, encode packet ino the pbuf(s) */
00147     ofs = snmp_resp_header_enc(m_stat, p);
00148     if (m_stat->error_status == SNMP_ES_TOOBIG)
00149     {
00150       snmp_varbind_list_enc(&emptyvb, p, ofs);
00151     }
00152     else
00153     {
00154       snmp_varbind_list_enc(&m_stat->outvb, p, ofs);
00155     }
00156 
00157     switch (m_stat->error_status)
00158     {
00159       case SNMP_ES_TOOBIG:
00160         snmp_inc_snmpouttoobigs();
00161         break;
00162       case SNMP_ES_NOSUCHNAME:
00163         snmp_inc_snmpoutnosuchnames();
00164         break;
00165       case SNMP_ES_BADVALUE:
00166         snmp_inc_snmpoutbadvalues();
00167         break;
00168       case SNMP_ES_GENERROR:
00169         snmp_inc_snmpoutgenerrs();
00170         break;
00171     }
00172     snmp_inc_snmpoutgetresponses();
00173     snmp_inc_snmpoutpkts();
00174 
00175     /** @todo do we need separate rx and tx pcbs for threaded case? */
00176     /** connect to the originating source */
00177     udp_connect(m_stat->pcb, &m_stat->sip, m_stat->sp);
00178     err = udp_send(m_stat->pcb, p);
00179     if (err == ERR_MEM)
00180     {
00181       /** @todo release some memory, retry and return tooBig? tooMuchHassle? */
00182       err = ERR_MEM;
00183     }
00184     else
00185     {
00186       err = ERR_OK;
00187     }
00188     /** disassociate remote address and port with this pcb */
00189     udp_disconnect(m_stat->pcb);
00190 
00191     pbuf_free(p);
00192     LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_snd_response() done\n"));
00193     return err;
00194   }
00195   else
00196   {
00197     /* first pbuf alloc try or retry alloc failed
00198        very low on memory, couldn't return tooBig */
00199     return ERR_MEM;
00200   }
00201 }
00202 
00203 
00204 /**
00205  * Sends an generic or enterprise specific trap message.
00206  *
00207  * @param generic_trap is the trap code
00208  * @param eoid points to enterprise object identifier
00209  * @param specific_trap used for enterprise traps when generic_trap == 6
00210  * @return ERR_OK when success, ERR_MEM if we're out of memory
00211  *
00212  * @note the caller is responsible for filling in outvb in the trap_msg
00213  * @note the use of the enterpise identifier field
00214  * is per RFC1215.
00215  * Use .iso.org.dod.internet.mgmt.mib-2.snmp for generic traps
00216  * and .iso.org.dod.internet.private.enterprises.yourenterprise
00217  * (sysObjectID) for specific traps.
00218  */
00219 err_t
00220 snmp_send_trap(s8_t generic_trap, struct snmp_obj_id *eoid, s32_t specific_trap)
00221 {
00222   struct snmp_trap_dst *td;
00223   struct netif *dst_if;
00224   ip_addr_t dst_ip;
00225   struct pbuf *p;
00226   u16_t i,tot_len;
00227 
00228   for (i=0, td = &trap_dst[0]; i<SNMP_TRAP_DESTINATIONS; i++, td++)
00229   {
00230     if ((td->enable != 0) && !ip_addr_isany(&td->dip))
00231     {
00232       /* network order trap destination */
00233       ip_addr_copy(trap_msg.dip, td->dip);
00234       /* lookup current source address for this dst */
00235       dst_if = ip_route(&td->dip);
00236       ip_addr_copy(dst_ip, dst_if->ip_addr);
00237       /* @todo: what about IPv6? */
00238       trap_msg.sip_raw[0] = ip4_addr1(&dst_ip);
00239       trap_msg.sip_raw[1] = ip4_addr2(&dst_ip);
00240       trap_msg.sip_raw[2] = ip4_addr3(&dst_ip);
00241       trap_msg.sip_raw[3] = ip4_addr4(&dst_ip);
00242       trap_msg.gen_trap = generic_trap;
00243       trap_msg.spc_trap = specific_trap;
00244       if (generic_trap == SNMP_GENTRAP_ENTERPRISESPC)
00245       {
00246         /* enterprise-Specific trap */
00247         trap_msg.enterprise = eoid;
00248       }
00249       else
00250       {
00251         /* generic (MIB-II) trap */
00252         snmp_get_snmpgrpid_ptr(&trap_msg.enterprise);
00253       }
00254       snmp_get_sysuptime(&trap_msg.ts);
00255 
00256       /* pass 0, calculate length fields */
00257       tot_len = snmp_varbind_list_sum(&trap_msg.outvb);
00258       tot_len = snmp_trap_header_sum(&trap_msg, tot_len);
00259 
00260       /* allocate pbuf(s) */
00261       p = pbuf_alloc(PBUF_TRANSPORT, tot_len, PBUF_POOL);
00262       if (p != NULL)
00263       {
00264         u16_t ofs;
00265 
00266         /* pass 1, encode packet ino the pbuf(s) */
00267         ofs = snmp_trap_header_enc(&trap_msg, p);
00268         snmp_varbind_list_enc(&trap_msg.outvb, p, ofs);
00269 
00270         snmp_inc_snmpouttraps();
00271         snmp_inc_snmpoutpkts();
00272 
00273         /** connect to the TRAP destination */
00274         udp_connect(trap_msg.pcb, &trap_msg.dip, SNMP_TRAP_PORT);
00275         udp_send(trap_msg.pcb, p);
00276         /** disassociate remote address and port with this pcb */
00277         udp_disconnect(trap_msg.pcb);
00278 
00279         pbuf_free(p);
00280       }
00281       else
00282       {
00283         return ERR_MEM;
00284       }
00285     }
00286   }
00287   return ERR_OK;
00288 }
00289 
00290 void
00291 snmp_coldstart_trap(void)
00292 {
00293   trap_msg.outvb.head = NULL;
00294   trap_msg.outvb.tail = NULL;
00295   trap_msg.outvb.count = 0;
00296   snmp_send_trap(SNMP_GENTRAP_COLDSTART, NULL, 0);
00297 }
00298 
00299 void
00300 snmp_authfail_trap(void)
00301 {
00302   u8_t enable;
00303   snmp_get_snmpenableauthentraps(&enable);
00304   if (enable == 1)
00305   {
00306     trap_msg.outvb.head = NULL;
00307     trap_msg.outvb.tail = NULL;
00308     trap_msg.outvb.count = 0;
00309     snmp_send_trap(SNMP_GENTRAP_AUTHFAIL, NULL, 0);
00310   }
00311 }
00312 
00313 /**
00314  * Sums response header field lengths from tail to head and
00315  * returns resp_header_lengths for second encoding pass.
00316  *
00317  * @param vb_len varbind-list length
00318  * @param rhl points to returned header lengths
00319  * @return the required lenght for encoding the response header
00320  */
00321 static u16_t
00322 snmp_resp_header_sum(struct snmp_msg_pstat *m_stat, u16_t vb_len)
00323 {
00324   u16_t tot_len;
00325   struct snmp_resp_header_lengths *rhl;
00326 
00327   rhl = &m_stat->rhl;
00328   tot_len = vb_len;
00329   snmp_asn1_enc_s32t_cnt(m_stat->error_index, &rhl->erridxlen);
00330   snmp_asn1_enc_length_cnt(rhl->erridxlen, &rhl->erridxlenlen);
00331   tot_len += 1 + rhl->erridxlenlen + rhl->erridxlen;
00332 
00333   snmp_asn1_enc_s32t_cnt(m_stat->error_status, &rhl->errstatlen);
00334   snmp_asn1_enc_length_cnt(rhl->errstatlen, &rhl->errstatlenlen);
00335   tot_len += 1 + rhl->errstatlenlen + rhl->errstatlen;
00336 
00337   snmp_asn1_enc_s32t_cnt(m_stat->rid, &rhl->ridlen);
00338   snmp_asn1_enc_length_cnt(rhl->ridlen, &rhl->ridlenlen);
00339   tot_len += 1 + rhl->ridlenlen + rhl->ridlen;
00340 
00341   rhl->pdulen = tot_len;
00342   snmp_asn1_enc_length_cnt(rhl->pdulen, &rhl->pdulenlen);
00343   tot_len += 1 + rhl->pdulenlen;
00344 
00345   rhl->comlen = m_stat->com_strlen;
00346   snmp_asn1_enc_length_cnt(rhl->comlen, &rhl->comlenlen);
00347   tot_len += 1 + rhl->comlenlen + rhl->comlen;
00348 
00349   snmp_asn1_enc_s32t_cnt(snmp_version, &rhl->verlen);
00350   snmp_asn1_enc_length_cnt(rhl->verlen, &rhl->verlenlen);
00351   tot_len += 1 + rhl->verlen + rhl->verlenlen;
00352 
00353   rhl->seqlen = tot_len;
00354   snmp_asn1_enc_length_cnt(rhl->seqlen, &rhl->seqlenlen);
00355   tot_len += 1 + rhl->seqlenlen;
00356 
00357   return tot_len;
00358 }
00359 
00360 /**
00361  * Sums trap header field lengths from tail to head and
00362  * returns trap_header_lengths for second encoding pass.
00363  *
00364  * @param vb_len varbind-list length
00365  * @param thl points to returned header lengths
00366  * @return the required lenght for encoding the trap header
00367  */
00368 static u16_t
00369 snmp_trap_header_sum(struct snmp_msg_trap *m_trap, u16_t vb_len)
00370 {
00371   u16_t tot_len;
00372   struct snmp_trap_header_lengths *thl;
00373 
00374   thl = &m_trap->thl;
00375   tot_len = vb_len;
00376 
00377   snmp_asn1_enc_u32t_cnt(m_trap->ts, &thl->tslen);
00378   snmp_asn1_enc_length_cnt(thl->tslen, &thl->tslenlen);
00379   tot_len += 1 + thl->tslen + thl->tslenlen;
00380 
00381   snmp_asn1_enc_s32t_cnt(m_trap->spc_trap, &thl->strplen);
00382   snmp_asn1_enc_length_cnt(thl->strplen, &thl->strplenlen);
00383   tot_len += 1 + thl->strplen + thl->strplenlen;
00384 
00385   snmp_asn1_enc_s32t_cnt(m_trap->gen_trap, &thl->gtrplen);
00386   snmp_asn1_enc_length_cnt(thl->gtrplen, &thl->gtrplenlen);
00387   tot_len += 1 + thl->gtrplen + thl->gtrplenlen;
00388 
00389   thl->aaddrlen = 4;
00390   snmp_asn1_enc_length_cnt(thl->aaddrlen, &thl->aaddrlenlen);
00391   tot_len += 1 + thl->aaddrlen + thl->aaddrlenlen;
00392 
00393   snmp_asn1_enc_oid_cnt(m_trap->enterprise->len, &m_trap->enterprise->id[0], &thl->eidlen);
00394   snmp_asn1_enc_length_cnt(thl->eidlen, &thl->eidlenlen);
00395   tot_len += 1 + thl->eidlen + thl->eidlenlen;
00396 
00397   thl->pdulen = tot_len;
00398   snmp_asn1_enc_length_cnt(thl->pdulen, &thl->pdulenlen);
00399   tot_len += 1 + thl->pdulenlen;
00400 
00401   thl->comlen = sizeof(snmp_publiccommunity) - 1;
00402   snmp_asn1_enc_length_cnt(thl->comlen, &thl->comlenlen);
00403   tot_len += 1 + thl->comlenlen + thl->comlen;
00404 
00405   snmp_asn1_enc_s32t_cnt(snmp_version, &thl->verlen);
00406   snmp_asn1_enc_length_cnt(thl->verlen, &thl->verlenlen);
00407   tot_len += 1 + thl->verlen + thl->verlenlen;
00408 
00409   thl->seqlen = tot_len;
00410   snmp_asn1_enc_length_cnt(thl->seqlen, &thl->seqlenlen);
00411   tot_len += 1 + thl->seqlenlen;
00412 
00413   return tot_len;
00414 }
00415 
00416 /**
00417  * Sums varbind lengths from tail to head and
00418  * annotates lengths in varbind for second encoding pass.
00419  *
00420  * @param root points to the root of the variable binding list
00421  * @return the required lenght for encoding the variable bindings
00422  */
00423 static u16_t
00424 snmp_varbind_list_sum(struct snmp_varbind_root *root)
00425 {
00426   struct snmp_varbind *vb;
00427   u32_t *uint_ptr;
00428   s32_t *sint_ptr;
00429   u16_t tot_len;
00430 
00431   tot_len = 0;
00432   vb = root->tail;
00433   while ( vb != NULL )
00434   {
00435     /* encoded value lenght depends on type */
00436     switch (vb->value_type)
00437     {
00438       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG):
00439         sint_ptr = (s32_t*)vb->value;
00440         snmp_asn1_enc_s32t_cnt(*sint_ptr, &vb->vlen);
00441         break;
00442       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER):
00443       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE):
00444       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS):
00445         uint_ptr = (u32_t*)vb->value;
00446         snmp_asn1_enc_u32t_cnt(*uint_ptr, &vb->vlen);
00447         break;
00448       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR):
00449       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_NUL):
00450       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR):
00451       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_OPAQUE):
00452         vb->vlen = vb->value_len;
00453         break;
00454       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID):
00455         sint_ptr = (s32_t*)vb->value;
00456         snmp_asn1_enc_oid_cnt(vb->value_len / sizeof(s32_t), sint_ptr, &vb->vlen);
00457         break;
00458       default:
00459         /* unsupported type */
00460         vb->vlen = 0;
00461         break;
00462     };
00463     /* encoding length of value length field */
00464     snmp_asn1_enc_length_cnt(vb->vlen, &vb->vlenlen);
00465     snmp_asn1_enc_oid_cnt(vb->ident_len, vb->ident, &vb->olen);
00466     snmp_asn1_enc_length_cnt(vb->olen, &vb->olenlen);
00467 
00468     vb->seqlen = 1 + vb->vlenlen + vb->vlen;
00469     vb->seqlen += 1 + vb->olenlen + vb->olen;
00470     snmp_asn1_enc_length_cnt(vb->seqlen, &vb->seqlenlen);
00471 
00472     /* varbind seq */
00473     tot_len += 1 + vb->seqlenlen + vb->seqlen;
00474 
00475     vb = vb->prev;
00476   }
00477 
00478   /* varbind-list seq */
00479   root->seqlen = tot_len;
00480   snmp_asn1_enc_length_cnt(root->seqlen, &root->seqlenlen);
00481   tot_len += 1 + root->seqlenlen;
00482 
00483   return tot_len;
00484 }
00485 
00486 /**
00487  * Encodes response header from head to tail.
00488  */
00489 static u16_t
00490 snmp_resp_header_enc(struct snmp_msg_pstat *m_stat, struct pbuf *p)
00491 {
00492   u16_t ofs;
00493 
00494   ofs = 0;
00495   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
00496   ofs += 1;
00497   snmp_asn1_enc_length(p, ofs, m_stat->rhl.seqlen);
00498   ofs += m_stat->rhl.seqlenlen;
00499 
00500   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00501   ofs += 1;
00502   snmp_asn1_enc_length(p, ofs, m_stat->rhl.verlen);
00503   ofs += m_stat->rhl.verlenlen;
00504   snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.verlen, snmp_version);
00505   ofs += m_stat->rhl.verlen;
00506 
00507   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR));
00508   ofs += 1;
00509   snmp_asn1_enc_length(p, ofs, m_stat->rhl.comlen);
00510   ofs += m_stat->rhl.comlenlen;
00511   snmp_asn1_enc_raw(p, ofs, m_stat->rhl.comlen, m_stat->community);
00512   ofs += m_stat->rhl.comlen;
00513 
00514   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_RESP));
00515   ofs += 1;
00516   snmp_asn1_enc_length(p, ofs, m_stat->rhl.pdulen);
00517   ofs += m_stat->rhl.pdulenlen;
00518 
00519   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00520   ofs += 1;
00521   snmp_asn1_enc_length(p, ofs, m_stat->rhl.ridlen);
00522   ofs += m_stat->rhl.ridlenlen;
00523   snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.ridlen, m_stat->rid);
00524   ofs += m_stat->rhl.ridlen;
00525 
00526   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00527   ofs += 1;
00528   snmp_asn1_enc_length(p, ofs, m_stat->rhl.errstatlen);
00529   ofs += m_stat->rhl.errstatlenlen;
00530   snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.errstatlen, m_stat->error_status);
00531   ofs += m_stat->rhl.errstatlen;
00532 
00533   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00534   ofs += 1;
00535   snmp_asn1_enc_length(p, ofs, m_stat->rhl.erridxlen);
00536   ofs += m_stat->rhl.erridxlenlen;
00537   snmp_asn1_enc_s32t(p, ofs, m_stat->rhl.erridxlen, m_stat->error_index);
00538   ofs += m_stat->rhl.erridxlen;
00539 
00540   return ofs;
00541 }
00542 
00543 /**
00544  * Encodes trap header from head to tail.
00545  */
00546 static u16_t
00547 snmp_trap_header_enc(struct snmp_msg_trap *m_trap, struct pbuf *p)
00548 {
00549   u16_t ofs;
00550 
00551   ofs = 0;
00552   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
00553   ofs += 1;
00554   snmp_asn1_enc_length(p, ofs, m_trap->thl.seqlen);
00555   ofs += m_trap->thl.seqlenlen;
00556 
00557   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00558   ofs += 1;
00559   snmp_asn1_enc_length(p, ofs, m_trap->thl.verlen);
00560   ofs += m_trap->thl.verlenlen;
00561   snmp_asn1_enc_s32t(p, ofs, m_trap->thl.verlen, snmp_version);
00562   ofs += m_trap->thl.verlen;
00563 
00564   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR));
00565   ofs += 1;
00566   snmp_asn1_enc_length(p, ofs, m_trap->thl.comlen);
00567   ofs += m_trap->thl.comlenlen;
00568   snmp_asn1_enc_raw(p, ofs, m_trap->thl.comlen, (u8_t *)&snmp_publiccommunity[0]);
00569   ofs += m_trap->thl.comlen;
00570 
00571   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_TRAP));
00572   ofs += 1;
00573   snmp_asn1_enc_length(p, ofs, m_trap->thl.pdulen);
00574   ofs += m_trap->thl.pdulenlen;
00575 
00576   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID));
00577   ofs += 1;
00578   snmp_asn1_enc_length(p, ofs, m_trap->thl.eidlen);
00579   ofs += m_trap->thl.eidlenlen;
00580   snmp_asn1_enc_oid(p, ofs, m_trap->enterprise->len, &m_trap->enterprise->id[0]);
00581   ofs += m_trap->thl.eidlen;
00582 
00583   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR));
00584   ofs += 1;
00585   snmp_asn1_enc_length(p, ofs, m_trap->thl.aaddrlen);
00586   ofs += m_trap->thl.aaddrlenlen;
00587   snmp_asn1_enc_raw(p, ofs, m_trap->thl.aaddrlen, &m_trap->sip_raw[0]);
00588   ofs += m_trap->thl.aaddrlen;
00589 
00590   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00591   ofs += 1;
00592   snmp_asn1_enc_length(p, ofs, m_trap->thl.gtrplen);
00593   ofs += m_trap->thl.gtrplenlen;
00594   snmp_asn1_enc_u32t(p, ofs, m_trap->thl.gtrplen, m_trap->gen_trap);
00595   ofs += m_trap->thl.gtrplen;
00596 
00597   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG));
00598   ofs += 1;
00599   snmp_asn1_enc_length(p, ofs, m_trap->thl.strplen);
00600   ofs += m_trap->thl.strplenlen;
00601   snmp_asn1_enc_u32t(p, ofs, m_trap->thl.strplen, m_trap->spc_trap);
00602   ofs += m_trap->thl.strplen;
00603 
00604   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS));
00605   ofs += 1;
00606   snmp_asn1_enc_length(p, ofs, m_trap->thl.tslen);
00607   ofs += m_trap->thl.tslenlen;
00608   snmp_asn1_enc_u32t(p, ofs, m_trap->thl.tslen, m_trap->ts);
00609   ofs += m_trap->thl.tslen;
00610 
00611   return ofs;
00612 }
00613 
00614 /**
00615  * Encodes varbind list from head to tail.
00616  */
00617 static u16_t
00618 snmp_varbind_list_enc(struct snmp_varbind_root *root, struct pbuf *p, u16_t ofs)
00619 {
00620   struct snmp_varbind *vb;
00621   s32_t *sint_ptr;
00622   u32_t *uint_ptr;
00623   u8_t *raw_ptr;
00624 
00625   snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
00626   ofs += 1;
00627   snmp_asn1_enc_length(p, ofs, root->seqlen);
00628   ofs += root->seqlenlen;
00629 
00630   vb = root->head;
00631   while ( vb != NULL )
00632   {
00633     snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ));
00634     ofs += 1;
00635     snmp_asn1_enc_length(p, ofs, vb->seqlen);
00636     ofs += vb->seqlenlen;
00637 
00638     snmp_asn1_enc_type(p, ofs, (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID));
00639     ofs += 1;
00640     snmp_asn1_enc_length(p, ofs, vb->olen);
00641     ofs += vb->olenlen;
00642     snmp_asn1_enc_oid(p, ofs, vb->ident_len, &vb->ident[0]);
00643     ofs += vb->olen;
00644 
00645     snmp_asn1_enc_type(p, ofs, vb->value_type);
00646     ofs += 1;
00647     snmp_asn1_enc_length(p, ofs, vb->vlen);
00648     ofs += vb->vlenlen;
00649 
00650     switch (vb->value_type)
00651     {
00652       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG):
00653         sint_ptr = (s32_t*)vb->value;
00654         snmp_asn1_enc_s32t(p, ofs, vb->vlen, *sint_ptr);
00655         break;
00656       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER):
00657       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE):
00658       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS):
00659         uint_ptr = (u32_t*)vb->value;
00660         snmp_asn1_enc_u32t(p, ofs, vb->vlen, *uint_ptr);
00661         break;
00662       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR):
00663       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR):
00664       case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_OPAQUE):
00665         raw_ptr = (u8_t*)vb->value;
00666         snmp_asn1_enc_raw(p, ofs, vb->vlen, raw_ptr);
00667         break;
00668       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_NUL):
00669         break;
00670       case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID):
00671         sint_ptr = (s32_t*)vb->value;
00672         snmp_asn1_enc_oid(p, ofs, vb->value_len / sizeof(s32_t), sint_ptr);
00673         break;
00674       default:
00675         /* unsupported type */
00676         break;
00677     };
00678     ofs += vb->vlen;
00679     vb = vb->next;
00680   }
00681   return ofs;
00682 }
00683 
00684 #endif /* LWIP_SNMP */