Used in Live Traffic Update Nokia LCD Display Project
Fork of NetServices by
lwip/core/snmp/msg_in.c
- Committer:
- segundo
- Date:
- 2010-11-09
- Revision:
- 0:ac1725ba162c
File content as of revision 0:ac1725ba162c:
/** * @file * SNMP input message processing (RFC1157). */ /* * 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> */ #include "lwip/opt.h" #if LWIP_SNMP /* don't build if not configured for use in lwipopts.h */ #include "lwip/snmp.h" #include "lwip/snmp_asn1.h" #include "lwip/snmp_msg.h" #include "lwip/snmp_structs.h" #include "lwip/ip_addr.h" #include "lwip/memp.h" #include "lwip/udp.h" #include "lwip/stats.h" #include <string.h> /* 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; static void snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *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); /** * 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; i<SNMP_CONCURRENT_REQUESTS; i++) { msg_ps->state = SNMP_MSG_EMPTY; msg_ps->error_index = 0; msg_ps->error_status = SNMP_ES_NOERROR; msg_ps++; } trap_msg.pcb = snmp1_pcb; #ifdef SNMP_PRIVATE_MIB_INIT /* If defined, rhis must be a function-like define to initialize the * private MIB after the stack has been initialized. * The private MIB can also be initialized in tcpip_callback (or after * the stack is initialized), this define is only for convenience. */ SNMP_PRIVATE_MIB_INIT(); #endif /* SNMP_PRIVATE_MIB_INIT */ /* The coldstart trap will only be output if our outgoing interface is up & configured */ snmp_coldstart_trap(); } static void snmp_error_response(struct snmp_msg_pstat *msg_ps, u8_t error) { snmp_varbind_list_free(&msg_ps->outvb); msg_ps->outvb = msg_ps->invb; msg_ps->invb.head = NULL; msg_ps->invb.tail = NULL; msg_ps->invb.count = 0; msg_ps->error_status = error; msg_ps->error_index = 1 + msg_ps->vb_idx; snmp_send_response(msg_ps); snmp_varbind_list_free(&msg_ps->outvb); msg_ps->state = SNMP_MSG_EMPTY; } static void snmp_ok_response(struct snmp_msg_pstat *msg_ps) { err_t err_ret; err_ret = snmp_send_response(msg_ps); if (err_ret == ERR_MEM) { /* serious memory problem, can't return tooBig */ } else { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event = %"S32_F"\n",msg_ps->error_status)); } /* free varbinds (if available) */ snmp_varbind_list_free(&msg_ps->invb); snmp_varbind_list_free(&msg_ps->outvb); msg_ps->state = SNMP_MSG_EMPTY; } /** * Service an internal or external event for SNMP GET. * * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1) * @param msg_ps points to the assosicated message process state */ static void snmp_msg_get_event(u8_t request_id, struct snmp_msg_pstat *msg_ps) { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_get_event: msg_ps->state==%"U16_F"\n",(u16_t)msg_ps->state)); if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF) { struct mib_external_node *en; struct snmp_name_ptr np; /* get_object_def() answer*/ en = msg_ps->ext_mib_node; np = msg_ps->ext_name_ptr; /* translate answer into a known lifeform */ en->get_object_def_a(request_id, np.ident_len, np.ident, &msg_ps->ext_object_def); if ((msg_ps->ext_object_def.instance != MIB_OBJECT_NONE) && (msg_ps->ext_object_def.access & MIB_ACCESS_READ)) { msg_ps->state = SNMP_MSG_EXTERNAL_GET_VALUE; en->get_value_q(request_id, &msg_ps->ext_object_def); } else { en->get_object_def_pc(request_id, np.ident_len, np.ident); /* search failed, object id points to unknown object (nosuchname) */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } else if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_VALUE) { struct mib_external_node *en; struct snmp_varbind *vb; /* get_value() answer */ en = msg_ps->ext_mib_node; /* allocate output varbind */ vb = (struct snmp_varbind *)memp_malloc(MEMP_SNMP_VARBIND); LWIP_ASSERT("vb != NULL",vb != NULL); if (vb != NULL) { vb->next = NULL; vb->prev = NULL; /* move name from invb to outvb */ vb->ident = msg_ps->vb_ptr->ident; vb->ident_len = msg_ps->vb_ptr->ident_len; /* ensure this memory is refereced once only */ msg_ps->vb_ptr->ident = NULL; msg_ps->vb_ptr->ident_len = 0; vb->value_type = msg_ps->ext_object_def.asn_type; LWIP_ASSERT("invalid length", msg_ps->ext_object_def.v_len <= 0xff); vb->value_len = (u8_t)msg_ps->ext_object_def.v_len; if (vb->value_len > 0) { LWIP_ASSERT("SNMP_MAX_OCTET_STRING_LEN is configured too low", vb->value_len <= SNMP_MAX_VALUE_SIZE); vb->value = memp_malloc(MEMP_SNMP_VALUE); LWIP_ASSERT("vb->value != NULL",vb->value != NULL); if (vb->value != NULL) { en->get_value_a(request_id, &msg_ps->ext_object_def, vb->value_len, vb->value); snmp_varbind_tail_add(&msg_ps->outvb, vb); /* search again (if vb_idx < msg_ps->invb.count) */ msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } else { en->get_value_pc(request_id, &msg_ps->ext_object_def); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: no variable space\n")); msg_ps->vb_ptr->ident = vb->ident; msg_ps->vb_ptr->ident_len = vb->ident_len; memp_free(MEMP_SNMP_VARBIND, vb); snmp_error_response(msg_ps,SNMP_ES_TOOBIG); } } else { /* vb->value_len == 0, empty value (e.g. empty string) */ en->get_value_a(request_id, &msg_ps->ext_object_def, 0, NULL); vb->value = NULL; snmp_varbind_tail_add(&msg_ps->outvb, vb); /* search again (if vb_idx < msg_ps->invb.count) */ msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } } else { en->get_value_pc(request_id, &msg_ps->ext_object_def); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: no outvb space\n")); snmp_error_response(msg_ps,SNMP_ES_TOOBIG); } } while ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) && (msg_ps->vb_idx < msg_ps->invb.count)) { struct mib_node *mn; struct snmp_name_ptr np; if (msg_ps->vb_idx == 0) { msg_ps->vb_ptr = msg_ps->invb.head; } else { msg_ps->vb_ptr = msg_ps->vb_ptr->next; } /** 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, &np); if (mn != NULL) { if (mn->node_type == MIB_NODE_EX) { /* external object */ struct mib_external_node *en = (struct mib_external_node*)mn; msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF; /* save en && args in msg_ps!! */ msg_ps->ext_mib_node = en; msg_ps->ext_name_ptr = np; en->get_object_def_q(en->addr_inf, request_id, np.ident_len, np.ident); } else { /* internal object */ struct obj_def object_def; msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF; mn->get_object_def(np.ident_len, np.ident, &object_def); if ((object_def.instance != MIB_OBJECT_NONE) && (object_def.access & MIB_ACCESS_READ)) { mn = mn; } else { /* search failed, object id points to unknown object (nosuchname) */ mn = NULL; } if (mn != NULL) { struct snmp_varbind *vb; msg_ps->state = SNMP_MSG_INTERNAL_GET_VALUE; /* allocate output varbind */ vb = (struct snmp_varbind *)memp_malloc(MEMP_SNMP_VARBIND); LWIP_ASSERT("vb != NULL",vb != NULL); if (vb != NULL) { vb->next = NULL; vb->prev = NULL; /* move name from invb to outvb */ vb->ident = msg_ps->vb_ptr->ident; vb->ident_len = msg_ps->vb_ptr->ident_len; /* ensure this memory is refereced once only */ msg_ps->vb_ptr->ident = NULL; msg_ps->vb_ptr->ident_len = 0; vb->value_type = object_def.asn_type; LWIP_ASSERT("invalid length", object_def.v_len <= 0xff); vb->value_len = (u8_t)object_def.v_len; if (vb->value_len > 0) { LWIP_ASSERT("SNMP_MAX_OCTET_STRING_LEN is configured too low", vb->value_len <= SNMP_MAX_VALUE_SIZE); vb->value = memp_malloc(MEMP_SNMP_VALUE); LWIP_ASSERT("vb->value != NULL",vb->value != NULL); if (vb->value != NULL) { mn->get_value(&object_def, vb->value_len, vb->value); snmp_varbind_tail_add(&msg_ps->outvb, vb); msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } else { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: couldn't allocate variable space\n")); msg_ps->vb_ptr->ident = vb->ident; msg_ps->vb_ptr->ident_len = vb->ident_len; memp_free(MEMP_SNMP_VARBIND, vb); snmp_error_response(msg_ps,SNMP_ES_TOOBIG); } } else { /* vb->value_len == 0, empty value (e.g. empty string) */ vb->value = NULL; snmp_varbind_tail_add(&msg_ps->outvb, vb); msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } } else { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_event: couldn't allocate outvb space\n")); snmp_error_response(msg_ps,SNMP_ES_TOOBIG); } } } } } else { mn = NULL; } if (mn == NULL) { /* mn == NULL, noSuchName */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } if ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) && (msg_ps->vb_idx == msg_ps->invb.count)) { snmp_ok_response(msg_ps); } } /** * Service an internal or external event for SNMP GETNEXT. * * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1) * @param msg_ps points to the assosicated message process state */ static void snmp_msg_getnext_event(u8_t request_id, struct snmp_msg_pstat *msg_ps) { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_getnext_event: msg_ps->state==%"U16_F"\n",(u16_t)msg_ps->state)); if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF) { struct mib_external_node *en; /* get_object_def() answer*/ en = msg_ps->ext_mib_node; /* translate answer into a known lifeform */ en->get_object_def_a(request_id, 1, &msg_ps->ext_oid.id[msg_ps->ext_oid.len - 1], &msg_ps->ext_object_def); if (msg_ps->ext_object_def.instance != MIB_OBJECT_NONE) { msg_ps->state = SNMP_MSG_EXTERNAL_GET_VALUE; en->get_value_q(request_id, &msg_ps->ext_object_def); } else { en->get_object_def_pc(request_id, 1, &msg_ps->ext_oid.id[msg_ps->ext_oid.len - 1]); /* search failed, object id points to unknown object (nosuchname) */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } else if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_VALUE) { struct mib_external_node *en; struct snmp_varbind *vb; /* get_value() answer */ en = msg_ps->ext_mib_node; LWIP_ASSERT("invalid length", msg_ps->ext_object_def.v_len <= 0xff); vb = snmp_varbind_alloc(&msg_ps->ext_oid, msg_ps->ext_object_def.asn_type, (u8_t)msg_ps->ext_object_def.v_len); if (vb != NULL) { en->get_value_a(request_id, &msg_ps->ext_object_def, vb->value_len, vb->value); snmp_varbind_tail_add(&msg_ps->outvb, vb); msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } else { en->get_value_pc(request_id, &msg_ps->ext_object_def); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_getnext_event: couldn't allocate outvb space\n")); snmp_error_response(msg_ps,SNMP_ES_TOOBIG); } } while ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) && (msg_ps->vb_idx < msg_ps->invb.count)) { struct mib_node *mn; struct snmp_obj_id oid; if (msg_ps->vb_idx == 0) { msg_ps->vb_ptr = msg_ps->invb.head; } else { msg_ps->vb_ptr = msg_ps->vb_ptr->next; } if (snmp_iso_prefix_expand(msg_ps->vb_ptr->ident_len, msg_ps->vb_ptr->ident, &oid)) { if (msg_ps->vb_ptr->ident_len > 3) { /* can offset ident_len and ident */ mn = snmp_expand_tree((struct mib_node*)&internet, msg_ps->vb_ptr->ident_len - 4, msg_ps->vb_ptr->ident + 4, &oid); } else { /* can't offset ident_len -4, ident + 4 */ mn = snmp_expand_tree((struct mib_node*)&internet, 0, NULL, &oid); } } else { mn = NULL; } if (mn != NULL) { if (mn->node_type == MIB_NODE_EX) { /* external object */ struct mib_external_node *en = (struct mib_external_node*)mn; msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF; /* save en && args in msg_ps!! */ msg_ps->ext_mib_node = en; msg_ps->ext_oid = oid; en->get_object_def_q(en->addr_inf, request_id, 1, &oid.id[oid.len - 1]); } else { /* internal object */ struct obj_def object_def; struct snmp_varbind *vb; msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF; mn->get_object_def(1, &oid.id[oid.len - 1], &object_def); LWIP_ASSERT("invalid length", object_def.v_len <= 0xff); vb = snmp_varbind_alloc(&oid, object_def.asn_type, (u8_t)object_def.v_len); if (vb != NULL) { msg_ps->state = SNMP_MSG_INTERNAL_GET_VALUE; mn->get_value(&object_def, object_def.v_len, vb->value); snmp_varbind_tail_add(&msg_ps->outvb, vb); msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } else { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv couldn't allocate outvb space\n")); snmp_error_response(msg_ps,SNMP_ES_TOOBIG); } } } if (mn == NULL) { /* mn == NULL, noSuchName */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } if ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) && (msg_ps->vb_idx == msg_ps->invb.count)) { snmp_ok_response(msg_ps); } } /** * Service an internal or external event for SNMP SET. * * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1) * @param msg_ps points to the assosicated message process state */ static void snmp_msg_set_event(u8_t request_id, struct snmp_msg_pstat *msg_ps) { LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_msg_set_event: msg_ps->state==%"U16_F"\n",(u16_t)msg_ps->state)); if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF) { struct mib_external_node *en; struct snmp_name_ptr np; /* get_object_def() answer*/ en = msg_ps->ext_mib_node; np = msg_ps->ext_name_ptr; /* translate answer into a known lifeform */ en->get_object_def_a(request_id, np.ident_len, np.ident, &msg_ps->ext_object_def); if (msg_ps->ext_object_def.instance != MIB_OBJECT_NONE) { msg_ps->state = SNMP_MSG_EXTERNAL_SET_TEST; en->set_test_q(request_id, &msg_ps->ext_object_def); } else { en->get_object_def_pc(request_id, np.ident_len, np.ident); /* search failed, object id points to unknown object (nosuchname) */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } else if (msg_ps->state == SNMP_MSG_EXTERNAL_SET_TEST) { struct mib_external_node *en; /* set_test() answer*/ en = msg_ps->ext_mib_node; if (msg_ps->ext_object_def.access & MIB_ACCESS_WRITE) { if ((msg_ps->ext_object_def.asn_type == msg_ps->vb_ptr->value_type) && (en->set_test_a(request_id,&msg_ps->ext_object_def, msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value) != 0)) { msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } else { en->set_test_pc(request_id,&msg_ps->ext_object_def); /* bad value */ snmp_error_response(msg_ps,SNMP_ES_BADVALUE); } } else { en->set_test_pc(request_id,&msg_ps->ext_object_def); /* object not available for set */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } else if (msg_ps->state == SNMP_MSG_EXTERNAL_GET_OBJDEF_S) { struct mib_external_node *en; struct snmp_name_ptr np; /* get_object_def() answer*/ en = msg_ps->ext_mib_node; np = msg_ps->ext_name_ptr; /* translate answer into a known lifeform */ en->get_object_def_a(request_id, np.ident_len, np.ident, &msg_ps->ext_object_def); if (msg_ps->ext_object_def.instance != MIB_OBJECT_NONE) { msg_ps->state = SNMP_MSG_EXTERNAL_SET_VALUE; en->set_value_q(request_id, &msg_ps->ext_object_def, msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value); } else { en->get_object_def_pc(request_id, np.ident_len, np.ident); /* set_value failed, object has disappeared for some odd reason?? */ snmp_error_response(msg_ps,SNMP_ES_GENERROR); } } else if (msg_ps->state == SNMP_MSG_EXTERNAL_SET_VALUE) { struct mib_external_node *en; /** set_value_a() */ en = msg_ps->ext_mib_node; en->set_value_a(request_id, &msg_ps->ext_object_def, msg_ps->vb_ptr->value_len, msg_ps->vb_ptr->value); /** @todo use set_value_pc() if toobig */ msg_ps->state = SNMP_MSG_INTERNAL_SET_VALUE; msg_ps->vb_idx += 1; } /* test all values before setting */ while ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) && (msg_ps->vb_idx < msg_ps->invb.count)) { struct mib_node *mn; struct snmp_name_ptr np; if (msg_ps->vb_idx == 0) { msg_ps->vb_ptr = msg_ps->invb.head; } else { msg_ps->vb_ptr = msg_ps->vb_ptr->next; } /** 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, &np); if (mn != NULL) { if (mn->node_type == MIB_NODE_EX) { /* external object */ struct mib_external_node *en = (struct mib_external_node*)mn; msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF; /* save en && args in msg_ps!! */ msg_ps->ext_mib_node = en; msg_ps->ext_name_ptr = np; en->get_object_def_q(en->addr_inf, request_id, np.ident_len, np.ident); } else { /* internal object */ struct obj_def object_def; msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF; mn->get_object_def(np.ident_len, np.ident, &object_def); if (object_def.instance != MIB_OBJECT_NONE) { mn = mn; } else { /* search failed, object id points to unknown object (nosuchname) */ mn = NULL; } if (mn != NULL) { msg_ps->state = SNMP_MSG_INTERNAL_SET_TEST; if (object_def.access & MIB_ACCESS_WRITE) { if ((object_def.asn_type == msg_ps->vb_ptr->value_type) && (mn->set_test(&object_def,msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value) != 0)) { msg_ps->state = SNMP_MSG_SEARCH_OBJ; msg_ps->vb_idx += 1; } else { /* bad value */ snmp_error_response(msg_ps,SNMP_ES_BADVALUE); } } else { /* object not available for set */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } } } } else { mn = NULL; } if (mn == NULL) { /* mn == NULL, noSuchName */ snmp_error_response(msg_ps,SNMP_ES_NOSUCHNAME); } } if ((msg_ps->state == SNMP_MSG_SEARCH_OBJ) && (msg_ps->vb_idx == msg_ps->invb.count)) { msg_ps->vb_idx = 0; msg_ps->state = SNMP_MSG_INTERNAL_SET_VALUE; } /* set all values "atomically" (be as "atomic" as possible) */ while ((msg_ps->state == SNMP_MSG_INTERNAL_SET_VALUE) && (msg_ps->vb_idx < msg_ps->invb.count)) { struct mib_node *mn; struct snmp_name_ptr np; if (msg_ps->vb_idx == 0) { msg_ps->vb_ptr = msg_ps->invb.head; } else { msg_ps->vb_ptr = msg_ps->vb_ptr->next; } /* skip iso prefix test, was done previously while settesting() */ mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->vb_ptr->ident_len - 4, msg_ps->vb_ptr->ident + 4, &np); /* check if object is still available (e.g. external hot-plug thingy present?) */ if (mn != NULL) { if (mn->node_type == MIB_NODE_EX) { /* external object */ struct mib_external_node *en = (struct mib_external_node*)mn; msg_ps->state = SNMP_MSG_EXTERNAL_GET_OBJDEF_S; /* save en && args in msg_ps!! */ msg_ps->ext_mib_node = en; msg_ps->ext_name_ptr = np; en->get_object_def_q(en->addr_inf, request_id, np.ident_len, np.ident); } else { /* internal object */ struct obj_def object_def; msg_ps->state = SNMP_MSG_INTERNAL_GET_OBJDEF_S; mn->get_object_def(np.ident_len, np.ident, &object_def); msg_ps->state = SNMP_MSG_INTERNAL_SET_VALUE; mn->set_value(&object_def,msg_ps->vb_ptr->value_len,msg_ps->vb_ptr->value); msg_ps->vb_idx += 1; } } } if ((msg_ps->state == SNMP_MSG_INTERNAL_SET_VALUE) && (msg_ps->vb_idx == msg_ps->invb.count)) { /* simply echo the input if we can set it @todo do we need to return the actual value? e.g. if value is silently modified or behaves sticky? */ msg_ps->outvb = msg_ps->invb; msg_ps->invb.head = NULL; msg_ps->invb.tail = NULL; msg_ps->invb.count = 0; snmp_ok_response(msg_ps); } } /** * Handle one internal or external event. * Called for one async event. (recv external/private answer) * * @param request_id identifies requests from 0 to (SNMP_CONCURRENT_REQUESTS-1) */ void snmp_msg_event(u8_t request_id) { struct snmp_msg_pstat *msg_ps; if (request_id < SNMP_CONCURRENT_REQUESTS) { msg_ps = &msg_input_list[request_id]; if (msg_ps->rt == SNMP_ASN1_PDU_GET_NEXT_REQ) { snmp_msg_getnext_event(request_id, msg_ps); } else if (msg_ps->rt == SNMP_ASN1_PDU_GET_REQ) { snmp_msg_get_event(request_id, msg_ps); } else if(msg_ps->rt == SNMP_ASN1_PDU_SET_REQ) { snmp_msg_set_event(request_id, msg_ps); } } } /* lwIP UDP receive callback function */ static void snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port) { struct snmp_msg_pstat *msg_ps; u8_t req_idx; err_t err_ret; u16_t payload_len = p->tot_len; u16_t payload_ofs = 0; u16_t varbind_ofs = 0; /* suppress unused argument warning */ LWIP_UNUSED_ARG(arg); /* traverse input message process list, look for SNMP_MSG_EMPTY */ msg_ps = &msg_input_list[0]; req_idx = 0; while ((req_idx < SNMP_CONCURRENT_REQUESTS) && (msg_ps->state != SNMP_MSG_EMPTY)) { req_idx++; msg_ps++; } if (req_idx == SNMP_CONCURRENT_REQUESTS) { /* exceeding number of concurrent requests */ pbuf_free(p); return; } /* accepting request */ snmp_inc_snmpinpkts(); /* record used 'protocol control block' */ msg_ps->pcb = pcb; /* source address (network order) */ msg_ps->sip = *addr; /* source port (host order (lwIP oddity)) */ msg_ps->sp = port; /* check total length, version, community, pdu type */ err_ret = snmp_pdu_header_check(p, payload_ofs, payload_len, &varbind_ofs, msg_ps); /* Only accept requests and requests without error (be robust) */ /* Reject response and trap headers or error requests as input! */ if ((err_ret != ERR_OK) || ((msg_ps->rt != SNMP_ASN1_PDU_GET_REQ) && (msg_ps->rt != SNMP_ASN1_PDU_GET_NEXT_REQ) && (msg_ps->rt != SNMP_ASN1_PDU_SET_REQ)) || ((msg_ps->error_status != SNMP_ES_NOERROR) || (msg_ps->error_index != 0)) ) { /* header check failed drop request silently, do not return error! */ pbuf_free(p); LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_pdu_header_check() failed\n")); return; } 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); /* we've decoded the incoming message, release input msg now */ pbuf_free(p); if ((err_ret != ERR_OK) || (msg_ps->invb.count == 0)) { /* varbind-list decode failed, or varbind list empty. drop request silently, do not return error! (errors are only returned for a specific varbind failure) */ LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_pdu_dec_varbindlist() failed\n")); return; } msg_ps->error_status = SNMP_ES_NOERROR; msg_ps->error_index = 0; /* find object for each variable binding */ msg_ps->state = SNMP_MSG_SEARCH_OBJ; /* first variable binding from list to inspect */ msg_ps->vb_idx = 0; LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv varbind cnt=%"U16_F"\n",(u16_t)msg_ps->invb.count)); /* handle input event and as much objects as possible in one go */ snmp_msg_event(req_idx); } /** * 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, ofs_base; u8_t len_octets; u8_t type; s32_t version; ofs_base = ofs; 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 = (u8_t)len; if (strncmp(snmp_publiccommunity, (const char*)m_stat->community, SNMP_COMMUNITY_STR_LEN) != 0) { /** @todo: move this if we need to check more names */ snmp_inc_snmpinbadcommunitynames(); snmp_authfail_trap(); 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 (no parse error) */ return ERR_ARG; } m_stat->rt = type & 0x1F; ofs += (1 + len_octets); if (len != (pdu_len - (ofs - ofs_base))) { /* decoded PDU length does not equal actual payload length */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } 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; } /* must be noError (0) for incoming requests. 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; } /* must be 0 for incoming requests. decode anyway to catch bad integers (and dirty tricks) */ derr = snmp_asn1_dec_s32t(p, ofs + 1 + len_octets, len, &m_stat->error_index); if (derr != ERR_OK) { /* can't decode */ snmp_inc_snmpinasnparseerrs(); return ERR_ARG; } 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)) || (len == 0) || (len > vb_len)) { 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 = (s32_t*)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 = (u32_t*)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): LWIP_ASSERT("invalid length", len <= 0xff); vb = snmp_varbind_alloc(&oid, type, (u8_t)len); if (vb != NULL) { derr = snmp_asn1_dec_raw(p, ofs + 1 + len_octets, len, vb->value_len, (u8_t*)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 = (s32_t*)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, (u8_t*)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; } 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 *)memp_malloc(MEMP_SNMP_VARBIND); LWIP_ASSERT("vb != NULL",vb != NULL); if (vb != NULL) { u8_t i; vb->next = NULL; vb->prev = NULL; i = oid->len; vb->ident_len = i; if (i > 0) { LWIP_ASSERT("SNMP_MAX_TREE_DEPTH is configured too low", i <= SNMP_MAX_TREE_DEPTH); /* allocate array of s32_t for our object identifier */ vb->ident = (s32_t*)memp_malloc(MEMP_SNMP_VALUE); LWIP_ASSERT("vb->ident != NULL",vb->ident != NULL); if (vb->ident == NULL) { memp_free(MEMP_SNMP_VARBIND, vb); return NULL; } while(i > 0) { i--; vb->ident[i] = oid->id[i]; } } else { /* i == 0, pass zero length object identifier */ vb->ident = NULL; } vb->value_type = type; vb->value_len = len; if (len > 0) { LWIP_ASSERT("SNMP_MAX_OCTET_STRING_LEN is configured too low", vb->value_len <= SNMP_MAX_VALUE_SIZE); /* allocate raw bytes for our object value */ vb->value = memp_malloc(MEMP_SNMP_VALUE); LWIP_ASSERT("vb->value != NULL",vb->value != NULL); if (vb->value == NULL) { if (vb->ident != NULL) { memp_free(MEMP_SNMP_VALUE, vb->ident); } memp_free(MEMP_SNMP_VARBIND, vb); return NULL; } } else { /* ASN1_NUL type, or zero length ASN1_OC_STR */ vb->value = NULL; } } return vb; } void snmp_varbind_free(struct snmp_varbind *vb) { if (vb->value != NULL ) { memp_free(MEMP_SNMP_VALUE, vb->value); } if (vb->ident != NULL ) { memp_free(MEMP_SNMP_VALUE, vb->ident); } memp_free(MEMP_SNMP_VARBIND, vb); } void snmp_varbind_list_free(struct snmp_varbind_root *root) { struct snmp_varbind *vb, *prev; vb = root->tail; while ( vb != NULL ) { prev = vb->prev; snmp_varbind_free(vb); vb = prev; } root->count = 0; root->head = NULL; root->tail = NULL; } 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; } 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 */