/** * @file * [EXPERIMENTAL] SNMP input message processing (RFC1157). * * EXPERIMENTAL dumb echo, this is not how the agent should respond. * This is for test purposes only, DO NOT USE THIS CODE IN REAL WORLD!! */ /* * 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 */ #include #include "arch/cc.h" #include "lwip/opt.h" #include "lwip/ip_addr.h" #include "lwip/mem.h" #include "lwip/udp.h" #include "lwip/stats.h" #include "lwip/snmp.h" #include "lwip/snmp_asn1.h" #include "lwip/snmp_msg.h" #include "lwip/snmp_structs.h" #if LWIP_SNMP #define LWIP_SNMP_DBG_LOOPBACK_TST 0 #define SNMP_CONCURRENT_REQUESTS 2 /* public (non-static) constants */ /** SNMP v1 == 0 */ const s32_t snmp_version = 0; /** default SNMP community string */ const char snmp_publiccommunity[7] = "public"; /* statically allocated buffers for SNMP_CONCURRENT_REQUESTS */ struct snmp_msg_pstat msg_input_list[SNMP_CONCURRENT_REQUESTS]; /* UDP Protocol Control Block */ struct udp_pcb *snmp1_pcb = NULL; static void snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port); static err_t snmp_pdu_header_check(struct pbuf *p, u16_t ofs, u16_t pdu_len, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat); static err_t snmp_pdu_dec_varbindlist(struct pbuf *p, u16_t ofs, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat); static struct snmp_varbind* snmp_varbind_alloc(struct snmp_obj_id *oid, u8_t type, u8_t len); static void snmp_varbind_free(struct snmp_varbind *vb); static void snmp_varbind_list_free(struct snmp_varbind_root *root); static void snmp_varbind_tail_add(struct snmp_varbind_root *root, struct snmp_varbind *vb); static struct snmp_varbind* snmp_varbind_tail_remove(struct snmp_varbind_root *root); /** * Starts SNMP Agent. * Allocates UDP pcb and binds it to IP_ADDR_ANY port 161. */ void snmp_init(void) { struct snmp_msg_pstat *msg_ps; u8_t i; snmp1_pcb = udp_new(); if (snmp1_pcb != NULL) { udp_recv(snmp1_pcb, snmp_recv, (void *)SNMP_IN_PORT); udp_bind(snmp1_pcb, IP_ADDR_ANY, SNMP_IN_PORT); } msg_ps = &msg_input_list[0]; for (i=0; istate = SNMP_MSG_EMPTY; msg_ps->error_index = 0; msg_ps->error_status = 0; msg_ps++; } trap_msg.pcb = snmp1_pcb; } /** * called for each variable binding (also for the fist one) */ void snmp_msg_event(struct snmp_msg_pstat *msg_ps) { struct mib_node *mn; struct obj_def object_def; if (msg_ps->state == SNMP_MSG_DEMUX) { if (msg_ps->vb_idx == 0) { msg_ps->vb_ptr = msg_ps->invb.head; } else { msg_ps->vb_ptr = msg_ps->vb_ptr->next; msg_ps->vb_idx += 1; } if (msg_ps->rt == SNMP_ASN1_PDU_GET_REQ) { /** test object identifier for .iso.org.dod.internet prefix */ if (snmp_iso_prefix_tst(msg_ps->vb_ptr->ident_len, msg_ps->vb_ptr->ident)) { mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->vb_ptr->ident_len - 4, msg_ps->vb_ptr->ident + 4, &object_def); } else { mn = NULL; } if (mn != NULL) { if (mn->node_type == MIB_NODE_EX) { /* external object */ msg_ps->state = SNMP_MSG_EXTERNAL; } else { /* internal object */ msg_ps->state = SNMP_MSG_INTERNAL; } } else { /* mn == NULL, noSuchName */ msg_ps->error_status = SNMP_ES_NOSUCHNAME; msg_ps->error_index = 1 + msg_ps->vb_idx; msg_ps->outvb.head = NULL; msg_ps->outvb.tail = NULL; msg_ps->outvb.count = 0; msg_ps->outvb.seqlen = 0; msg_ps->outvb.seqlenlen = 1; snmp_send_response(msg_ps); msg_ps->state = SNMP_MSG_EMPTY; } } else if (msg_ps->rt == SNMP_ASN1_PDU_GET_NEXT_REQ) { } else if (msg_ps->rt == SNMP_ASN1_PDU_SET_REQ) { } else { /** @todo not a request, return generror?? */ } } else if (msg_ps->state == SNMP_MSG_INTERNAL) { } else if (msg_ps->state == SNMP_MSG_EXTERNAL) { } } /* lwIP UDP receive callback function */ static void snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port) { struct udp_hdr *udphdr; /* suppress unused argument warning */ if (arg); /* peek in the UDP header (goto IP payload) */ pbuf_header(p, UDP_HLEN); udphdr = p->payload; /* check if datagram is really directed at us (including broadcast requests) */ if ((pcb == snmp1_pcb) && (ntohs(udphdr->dest) == 161)) { struct snmp_msg_pstat *msg_ps; u8_t i; /* traverse input message process list, look for SNMP_MSG_EMPTY */ msg_ps = &msg_input_list[0]; i = 0; while ((istate != SNMP_MSG_EMPTY)) { i++; msg_ps++; } if (i != SNMP_CONCURRENT_REQUESTS) { err_t err_ret; u16_t payload_len; u16_t payload_ofs; u16_t varbind_ofs; /* accepting request */ snmp_inc_snmpinpkts(); /* register 'protocol control block' used */ msg_ps->pcb = pcb; /* source address (network order) */ msg_ps->sip = *addr; /* source port (host order (lwIP oddity)) */ msg_ps->sp = port; /* demultiplex variable bindings */ msg_ps->state = SNMP_MSG_DEMUX; /* first variable binding from list to inspect */ msg_ps->vb_idx = 0; /* read UDP payload length from UDP header */ payload_len = ntohs(udphdr->len) - UDP_HLEN; /* adjust to UDP payload */ payload_ofs = UDP_HLEN; /* check total length, version, community, pdu type */ err_ret = snmp_pdu_header_check(p, payload_ofs, payload_len, &varbind_ofs, msg_ps); if (err_ret == ERR_OK) { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv ok, community %s\n", msg_ps->community)); /* Builds a list of variable bindings. Copy the varbinds from the pbuf chain to glue them when these are divided over two or more pbuf's. */ err_ret = snmp_pdu_dec_varbindlist(p, varbind_ofs, &varbind_ofs, msg_ps); if ((err_ret == ERR_OK) && (msg_ps->invb.count > 0)) { struct mib_node *mn; struct obj_def object_def; /* we've decoded the incoming message, release input msg now */ pbuf_free(p); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv varbind cnt=%"U16_F"\n",(u16_t)msg_ps->invb.count)); if (msg_ps->rt == SNMP_ASN1_PDU_GET_REQ) { /** test object identifier for .iso.org.dod.internet prefix */ if (snmp_iso_prefix_tst(msg_ps->invb.head->ident_len, msg_ps->invb.head->ident)) { mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->invb.head->ident_len - 4, msg_ps->invb.head->ident + 4, &object_def); } else { mn = NULL; } if (mn != NULL) { if (msg_ps->invb.head->value != NULL) { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv free value before vb recycle")); mem_free(msg_ps->invb.head->value); } msg_ps->invb.head->value_type = object_def.asn_type; msg_ps->invb.head->value_len = object_def.v_len; msg_ps->invb.head->value = mem_malloc(object_def.v_len); if (msg_ps->invb.head->value != NULL) { mn->get_value(&object_def, object_def.v_len, msg_ps->invb.head->value); } else { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv couldn't allocate variable space")); } msg_ps->outvb = msg_ps->invb; } else { /* mn == NULL, noSuchName */ msg_ps->error_status = SNMP_ES_NOSUCHNAME; msg_ps->error_index = 1 + msg_ps->vb_idx; msg_ps->outvb.head = NULL; msg_ps->outvb.tail = NULL; msg_ps->outvb.count = 0; msg_ps->outvb.seqlen = 0; msg_ps->outvb.seqlenlen = 1; } } else { /* request != GET */ /** @todo EXPERIMENTAL dumb echo, this is not how the agent should respond. This is for test purposes only, do not use this in real world!! */ msg_ps->outvb = msg_ps->invb; msg_ps->error_status = SNMP_ES_NOERROR; msg_ps->error_index = 0; } /* when more variable bindings left msg_ps->state = SNMP_MSG_DEMUX */ /* when completed transaction */ err_ret = snmp_send_response(msg_ps); if (err_ret == ERR_MEM) { /* serious memory problem, can't return tooBig */ #if LWIP_STATS LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv pbufs.used = %"U16_F"\n",lwip_stats.pbuf.used)); #endif } else { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_response error_status = %"S32_F"\n",msg_ps->error_status)); } /* free varbinds (if available) */ snmp_varbind_list_free(&msg_ps->invb); msg_ps->state = SNMP_MSG_EMPTY; } else { /* varbind-list decode failed, or varbind list empty (silly cmd for agent) */ pbuf_free(p); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_pdu_dec_varbindlist() failed")); msg_ps->error_status = SNMP_ES_GENERROR; msg_ps->error_index = 0; msg_ps->outvb.head = NULL; msg_ps->outvb.tail = NULL; msg_ps->outvb.count = 0; msg_ps->outvb.seqlen = 0; msg_ps->outvb.seqlenlen = 1; snmp_send_response(msg_ps); } } else { /* header check failed! */ pbuf_free(p); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_pdu_header_check() failed")); } } else { /* exceeding number of concurrent requests */ pbuf_free(p); } } else { /* datagram not for us */ pbuf_free(p); } } /** * Checks and decodes incoming SNMP message header, logs header errors. * * @param p points to pbuf chain of SNMP message (UDP payload) * @param ofs points to first octet of SNMP message * @param pdu_len the length of the UDP payload * @param ofs_ret returns the ofset of the variable bindings * @param m_stat points to the current message request state return * @return * - ERR_OK SNMP header is sane and accepted * - ERR_ARG SNMP header is either malformed or rejected */ static err_t snmp_pdu_header_check(struct pbuf *p, u16_t ofs, u16_t pdu_len, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat) { err_t derr; u16_t len; u8_t len_octets; u8_t type; s32_t version; snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (pdu_len != (1 + len_octets + len)) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ))) { snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } ofs += (1 + len_octets); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG))) { /* can't decode or no integer (version) */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &version); if (derr != ERR_OK) { /* can't decode */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } if (version != 0) { /* not version 1 */ snmp_inc_snmpinbadversions(); return ERR_ARG; } ofs += (1 + len_octets + len); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR))) { /* can't decode or no octet string (community) */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, SNMP_COMMUNITY_STR_LEN, m_stat->community); if (derr != ERR_OK) { snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } /* add zero terminator */ len = ((len < (SNMP_COMMUNITY_STR_LEN))?(len):(SNMP_COMMUNITY_STR_LEN)); m_stat->community[len] = 0; m_stat->com_strlen = len; if (strncmp(snmp_publiccommunity, m_stat->community, SNMP_COMMUNITY_STR_LEN) != 0) { /** @todo: move this if we need to check more names */ snmp_inc_snmpinbadcommunitynames(); /** @todo: send authentication failure trap, if we have a trap destination */ return ERR_ARG; } ofs += (1 + len_octets + len); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if (derr != ERR_OK) { snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } switch(type) { case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_REQ): /* GetRequest PDU */ snmp_inc_snmpingetrequests(); derr = ERR_OK; break; case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_NEXT_REQ): /* GetNextRequest PDU */ snmp_inc_snmpingetnexts(); derr = ERR_OK; break; case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_GET_RESP): /* GetResponse PDU */ snmp_inc_snmpingetresponses(); derr = ERR_ARG; break; case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_SET_REQ): /* SetRequest PDU */ snmp_inc_snmpinsetrequests(); derr = ERR_OK; break; case (SNMP_ASN1_CONTXT | SNMP_ASN1_CONSTR | SNMP_ASN1_PDU_TRAP): /* Trap PDU */ snmp_inc_snmpintraps(); derr = ERR_ARG; break; default: snmp_inc_snmpinasnparseerrs(); derr = ERR_ARG; break; } if (derr != ERR_OK) { /* unsupported input PDU for this agent */ return ERR_ARG; } m_stat->rt = type & 0x1F; ofs += (1 + len_octets); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG))) { /* can't decode or no integer (request ID) */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &m_stat->rid); if (derr != ERR_OK) { /* can't decode */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } ofs += (1 + len_octets + len); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG))) { /* can't decode or no integer (error-status) */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } /* usually noError (0) for incoming messages but log errors for mib-2 completeness and for debug purposes */ derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &m_stat->error_status); if (derr != ERR_OK) { /* can't decode */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } switch (m_stat->error_status) { case SNMP_ES_TOOBIG: snmp_inc_snmpintoobigs(); break; case SNMP_ES_NOSUCHNAME: snmp_inc_snmpinnosuchnames(); break; case SNMP_ES_BADVALUE: snmp_inc_snmpinbadvalues(); break; case SNMP_ES_READONLY: snmp_inc_snmpinreadonlys(); break; case SNMP_ES_GENERROR: snmp_inc_snmpingenerrs(); break; } ofs += (1 + len_octets + len); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG))) { /* can't decode or no integer (error-index) */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } /* skip 'error-index', usually 0 for incoming requests */ ofs += (1 + len_octets + len); *ofs_ret = ofs; return ERR_OK; } static err_t snmp_pdu_dec_varbindlist(struct pbuf *p, u16_t ofs, u16_t *ofs_ret, struct snmp_msg_pstat *m_stat) { err_t derr; u16_t len, vb_len; u8_t len_octets; u8_t type; /* variable binding list */ snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &vb_len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ))) { snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } ofs += (1 + len_octets); /* start with empty list */ m_stat->invb.count = 0; m_stat->invb.head = NULL; m_stat->invb.tail = NULL; while (vb_len > 0) { struct snmp_obj_id oid, oid_value; struct snmp_varbind *vb; snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_CONSTR | SNMP_ASN1_SEQ))) { snmp_inc_snmpinasnparseerrs(); /* free varbinds (if available) */ snmp_varbind_list_free(&m_stat->invb); return ERR_ARG; } ofs += (1 + len_octets); vb_len -= (1 + len_octets); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if ((derr != ERR_OK) || (type != (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID))) { /* can't decode object name length */ snmp_inc_snmpinasnparseerrs(); /* free varbinds (if available) */ snmp_varbind_list_free(&m_stat->invb); return ERR_ARG; } derr = snmp_asn1_dec_oid(p, ofs + 1 + len_octets, len, &oid); if (derr != ERR_OK) { /* can't decode object name */ snmp_inc_snmpinasnparseerrs(); /* free varbinds (if available) */ snmp_varbind_list_free(&m_stat->invb); return ERR_ARG; } ofs += (1 + len_octets + len); vb_len -= (1 + len_octets + len); snmp_asn1_dec_type(p, ofs, &type); derr = snmp_asn1_dec_length(p, ofs+1, &len_octets, &len); if (derr != ERR_OK) { /* can't decode object value length */ snmp_inc_snmpinasnparseerrs(); /* free varbinds (if available) */ snmp_varbind_list_free(&m_stat->invb); return ERR_ARG; } switch (type) { case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_INTEG): vb = snmp_varbind_alloc(&oid, type, sizeof(s32_t)); if (vb != NULL) { s32_t *vptr = vb->value; derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, vptr); snmp_varbind_tail_add(&m_stat->invb, vb); } else { derr = ERR_ARG; } break; case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_COUNTER): case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_GAUGE): case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_TIMETICKS): vb = snmp_varbind_alloc(&oid, type, sizeof(u32_t)); if (vb != NULL) { u32_t *vptr = vb->value; derr = snmp_asn1_dec_u32t(p, ofs + 1 + len_octets, len, vptr); snmp_varbind_tail_add(&m_stat->invb, vb); } else { derr = ERR_ARG; } break; case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OC_STR): case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_OPAQUE): vb = snmp_varbind_alloc(&oid, type, len); if (vb != NULL) { derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, vb->value_len, vb->value); snmp_varbind_tail_add(&m_stat->invb, vb); } else { derr = ERR_ARG; } break; case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_NUL): vb = snmp_varbind_alloc(&oid, type, 0); if (vb != NULL) { snmp_varbind_tail_add(&m_stat->invb, vb); derr = ERR_OK; } else { derr = ERR_ARG; } break; case (SNMP_ASN1_UNIV | SNMP_ASN1_PRIMIT | SNMP_ASN1_OBJ_ID): derr = snmp_asn1_dec_oid(p, ofs + 1 + len_octets, len, &oid_value); if (derr == ERR_OK) { vb = snmp_varbind_alloc(&oid, type, oid_value.len * sizeof(s32_t)); if (vb != NULL) { u8_t i = oid_value.len; s32_t *vptr = vb->value; while(i > 0) { i--; vptr[i] = oid_value.id[i]; } snmp_varbind_tail_add(&m_stat->invb, vb); derr = ERR_OK; } else { derr = ERR_ARG; } } break; case (SNMP_ASN1_APPLIC | SNMP_ASN1_PRIMIT | SNMP_ASN1_IPADDR): if (len == 4) { /* must be exactly 4 octets! */ vb = snmp_varbind_alloc(&oid, type, 4); if (vb != NULL) { derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, vb->value_len, vb->value); snmp_varbind_tail_add(&m_stat->invb, vb); } else { derr = ERR_ARG; } } else { derr = ERR_ARG; } break; default: derr = ERR_ARG; break; } if (derr != ERR_OK) { snmp_inc_snmpinasnparseerrs(); /* free varbinds (if available) */ snmp_varbind_list_free(&m_stat->invb); return ERR_ARG; } ofs += (1 + len_octets + len); vb_len -= (1 + len_octets + len); } if (m_stat->rt == SNMP_ASN1_PDU_SET_REQ) { snmp_add_snmpintotalsetvars(m_stat->invb.count); } else { snmp_add_snmpintotalreqvars(m_stat->invb.count); } *ofs_ret = ofs; return ERR_OK; } static struct snmp_varbind* snmp_varbind_alloc(struct snmp_obj_id *oid, u8_t type, u8_t len) { struct snmp_varbind *vb; vb = (struct snmp_varbind *)mem_malloc(sizeof(struct snmp_varbind)); if (vb != NULL) { u8_t i; vb->next = NULL; vb->prev = NULL; i = oid->len; vb->ident_len = i; /* allocate array of s32_t for our object identifier */ vb->ident = (s32_t*)mem_malloc(sizeof(s32_t) * i); if (vb->ident == NULL) { mem_free(vb); return NULL; } while(i > 0) { i--; vb->ident[i] = oid->id[i]; } vb->value_type = type; vb->value_len = len; if (len > 0) { /* allocate raw bytes for our object value */ vb->value = mem_malloc(len); if (vb->value == NULL) { mem_free(vb->ident); mem_free(vb); return NULL; } } else { /* ASN1_NUL type, or zero length ASN1_OC_STR */ vb->value = NULL; } } return vb; } static void snmp_varbind_free(struct snmp_varbind *vb) { if (vb->value != NULL ) { mem_free(vb->value); } if (vb->ident != NULL ) { mem_free(vb->ident); } mem_free(vb); } static void snmp_varbind_list_free(struct snmp_varbind_root *root) { struct snmp_varbind *vb; vb = root->tail; while ( vb != NULL ) { snmp_varbind_free(vb); vb = vb->prev; } root->count = 0; } static void snmp_varbind_tail_add(struct snmp_varbind_root *root, struct snmp_varbind *vb) { if (root->count == 0) { /* add first varbind to list */ root->head = vb; root->tail = vb; } else { /* add nth varbind to list tail */ root->tail->next = vb; vb->prev = root->tail; root->tail = vb; } root->count += 1; } static struct snmp_varbind* snmp_varbind_tail_remove(struct snmp_varbind_root *root) { struct snmp_varbind* vb; if (root->count > 0) { /* remove tail varbind */ vb = root->tail; root->tail = vb->prev; vb->prev->next = NULL; root->count -= 1; } else { /* nothing to remove */ vb = NULL; } return vb; } #endif /* LWIP_SNMP */