static err_t
snmp_prepare_outbound_frame(struct snmp_request *request)
{
struct snmp_asn1_tlv tlv;
struct snmp_pbuf_stream* pbuf_stream = &(request->outbound_pbuf_stream);
/* try allocating pbuf(s) for maximum response size */
request->outbound_pbuf = pbuf_alloc(PBUF_TRANSPORT, 1472, PBUF_RAM);
if (request->outbound_pbuf == NULL) {
return ERR_MEM;
}
snmp_pbuf_stream_init(pbuf_stream, request->outbound_pbuf, 0, request->outbound_pbuf->tot_len);
/* 'Message' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, 0);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
/* version */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(request->version, &tlv.value_len);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
OF_BUILD_EXEC( snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->version) );
/* community */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, request->community_strlen);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
OF_BUILD_EXEC( snmp_asn1_enc_raw(pbuf_stream, request->community, request->community_strlen) );
/* 'PDU' sequence */
request->outbound_pdu_offset = pbuf_stream->offset;
SNMP_ASN1_SET_TLV_PARAMS(tlv, (SNMP_ASN1_CLASS_CONTEXT | SNMP_ASN1_CONTENTTYPE_CONSTRUCTED | SNMP_ASN1_CONTEXT_PDU_GET_RESP), 3, 0);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
/* request ID */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(request->request_id, &tlv.value_len);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
OF_BUILD_EXEC( snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, request->request_id) );
/* error status */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 1);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
request->outbound_error_status_offset = pbuf_stream->offset;
snmp_pbuf_stream_write(pbuf_stream, 0);
/* error index */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 1);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
request->outbound_error_index_offset = pbuf_stream->offset;
snmp_pbuf_stream_write(pbuf_stream, 0);
/* 'VarBindList' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, 0);
OF_BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
request->outbound_varbind_offset = pbuf_stream->offset;
return ERR_OK;
}
static err_t
snmp_trap_varbind_enc(struct snmp_msg_trap *trap, struct snmp_pbuf_stream *pbuf_stream, struct snmp_varbind *varbinds)
{
struct snmp_asn1_tlv tlv;
struct snmp_varbind *varbind;
varbind = varbinds;
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 0, trap->vbseqlen);
BUILD_EXEC( snmp_ans1_enc_tlv(pbuf_stream, &tlv) );
while (varbind != NULL) {
BUILD_EXEC( snmp_append_outbound_varbind(pbuf_stream, varbind) );
varbind = varbind->next;
}
return ERR_OK;
}
/**
* Encodes trap header from head to tail.
*/
static void
snmp_trap_header_enc(struct snmp_msg_trap *trap, struct snmp_pbuf_stream *pbuf_stream)
{
struct snmp_asn1_tlv tlv;
/* 'Message' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 0, trap->seqlen);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
/* version */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(trap->snmp_version, &tlv.value_len);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, trap->snmp_version);
/* community */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OCTET_STRING, 0, trap->comlen);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_raw(pbuf_stream, (const u8_t *)snmp_community_trap, trap->comlen);
/* 'PDU' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, (SNMP_ASN1_CLASS_CONTEXT | SNMP_ASN1_CONTENTTYPE_CONSTRUCTED | SNMP_ASN1_CONTEXT_PDU_TRAP), 0, trap->pdulen);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
/* object ID */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OBJECT_ID, 0, 0);
snmp_asn1_enc_oid_cnt(trap->enterprise->id, trap->enterprise->len, &tlv.value_len);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_oid(pbuf_stream, trap->enterprise->id, trap->enterprise->len);
/* IP addr */
if(IP_IS_V6_VAL(trap->sip)) {
#if LWIP_IPV6
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_IPADDR, 0, sizeof(ip_2_ip6(&trap->sip)->addr));
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_raw(pbuf_stream, (const u8_t *)&ip_2_ip6(&trap->sip)->addr, sizeof(ip_2_ip6(&trap->sip)->addr));
#endif
} else {
#if LWIP_IPV4
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_IPADDR, 0, sizeof(ip_2_ip4(&trap->sip)->addr));
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_raw(pbuf_stream, (const u8_t *)&ip_2_ip4(&trap->sip)->addr, sizeof(ip_2_ip4(&trap->sip)->addr));
#endif
}
/* trap length */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(trap->gen_trap, &tlv.value_len);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, trap->gen_trap);
/* specific trap */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_INTEGER, 0, 0);
snmp_asn1_enc_s32t_cnt(trap->spc_trap, &tlv.value_len);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, trap->spc_trap);
/* timestamp */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_TIMETICKS, 0, 0);
snmp_asn1_enc_s32t_cnt(trap->ts, &tlv.value_len);
snmp_ans1_enc_tlv(pbuf_stream, &tlv);
snmp_asn1_enc_s32t(pbuf_stream, tlv.value_len, trap->ts);
}
static err_t
snmp_complete_outbound_frame(struct snmp_request *request)
{
struct snmp_asn1_tlv tlv;
u16_t frame_size;
if (request->version == SNMP_VERSION_1) {
if (request->error_status != SNMP_ERR_NOERROR) {
/* map v2c error codes to v1 compliant error code (according to RFC 2089) */
switch (request->error_status) {
/* mapping of implementation specific "virtual" error codes
* (during processing of frame we already stored them in error_status field,
* so no need to check all varbinds here for those exceptions as suggested by RFC) */
case SNMP_ERR_NOSUCHINSTANCE:
case SNMP_ERR_NOSUCHOBJECT:
case SNMP_ERR_ENDOFMIBVIEW:
request->error_status = SNMP_ERR_NOSUCHNAME; break;
/* mapping according to RFC */
case SNMP_ERR_WRONGVALUE:
case SNMP_ERR_WRONGENCODING:
case SNMP_ERR_WRONGTYPE:
case SNMP_ERR_WRONGLENGTH:
case SNMP_ERR_INCONSISTENTVALUE:
request->error_status = SNMP_ERR_BADVALUE; break;
case SNMP_ERR_NOACCESS:
case SNMP_ERR_NOTWRITABLE:
case SNMP_ERR_NOCREATION:
case SNMP_ERR_INCONSISTENTNAME:
case SNMP_ERR_AUTHORIZATIONERROR:
request->error_status = SNMP_ERR_NOSUCHNAME; break;
case SNMP_ERR_RESOURCEUNAVAILABLE:
case SNMP_ERR_COMMITFAILED:
case SNMP_ERR_UNDOFAILED:
default:
request->error_status = SNMP_ERR_GENERROR; break;
}
}
} else {
if (request->error_status >= SNMP_VARBIND_EXCEPTION_OFFSET) {
/* should never occur because v2 frames store exceptions directly inside varbinds and not as frame error_status */
LWIP_DEBUGF(SNMP_DEBUG, ("snmp_complete_outbound_frame() > Found v2 request with varbind exception code stored as error status!\n"));
return ERR_ABRT;
}
}
if ((request->error_status != SNMP_ERR_NOERROR) || (request->request_type == SNMP_ASN1_CONTEXT_PDU_SET_REQ)) {
/* all inbound vars are returned in response without any modification for error responses and successful set requests*/
struct snmp_pbuf_stream inbound_stream;
OF_BUILD_EXEC( snmp_pbuf_stream_init(&inbound_stream, request->inbound_pbuf, request->inbound_varbind_offset, request->inbound_varbind_len) );
OF_BUILD_EXEC( snmp_pbuf_stream_init(&(request->outbound_pbuf_stream), request->outbound_pbuf, request->outbound_varbind_offset, request->outbound_pbuf->tot_len - request->outbound_varbind_offset) );
snmp_pbuf_stream_writeto(&inbound_stream, &(request->outbound_pbuf_stream), 0);
}
frame_size = request->outbound_pbuf_stream.offset;
/* complete mssing length in 'Message' sequence ; 'Message' tlv is located at the beginning (offset 0) */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, frame_size - 1 - 3); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
OF_BUILD_EXEC( snmp_pbuf_stream_init(&(request->outbound_pbuf_stream), request->outbound_pbuf, 0, request->outbound_pbuf->tot_len) );
OF_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
/* complete mssing length in 'PDU' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, (SNMP_ASN1_CLASS_CONTEXT | SNMP_ASN1_CONTENTTYPE_CONSTRUCTED | SNMP_ASN1_CONTEXT_PDU_GET_RESP), 3, frame_size - request->outbound_pdu_offset - 1 - 3); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
OF_BUILD_EXEC( snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_pdu_offset) );
OF_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
/* process and encode final error status */
if (request->error_status != 0) {
u16_t len;
snmp_asn1_enc_s32t_cnt(request->error_status, &len);
if (len != 1) {
/* error, we only reserved one byte for it */
return ERR_ABRT;
}
OF_BUILD_EXEC( snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_error_status_offset) );
OF_BUILD_EXEC( snmp_asn1_enc_s32t(&(request->outbound_pbuf_stream), len, request->error_status) );
/* for compatibility to v1, log statistics; in v2 (RFC 1907) these statistics are obsoleted */
switch (request->error_status) {
case SNMP_ERR_TOOBIG:
snmp_stats.outtoobigs++;
break;
case SNMP_ERR_NOSUCHNAME:
snmp_stats.outnosuchnames++;
break;
case SNMP_ERR_BADVALUE:
snmp_stats.outbadvalues++;
break;
case SNMP_ERR_GENERROR:
default:
snmp_stats.outgenerrs++;
break;
}
if (request->error_status == SNMP_ERR_TOOBIG) {
request->error_index = 0; /* defined by RFC 1157 */
} else if (request->error_index == 0) {
/* set index to varbind where error occured (if not already set before, e.g. during GetBulk processing) */
request->error_index = request->inbound_varbind_enumerator.varbind_count;
}
} else {
if (request->request_type == SNMP_ASN1_CONTEXT_PDU_SET_REQ) {
snmp_stats.intotalsetvars += request->inbound_varbind_enumerator.varbind_count;
} else {
snmp_stats.intotalreqvars += request->inbound_varbind_enumerator.varbind_count;
}
}
/* encode final error index*/
if (request->error_index != 0) {
u16_t len;
snmp_asn1_enc_s32t_cnt(request->error_index, &len);
if (len != 1) {
/* error, we only reserved one byte for it */
return ERR_VAL;
}
OF_BUILD_EXEC( snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_error_index_offset) );
OF_BUILD_EXEC( snmp_asn1_enc_s32t(&(request->outbound_pbuf_stream), len, request->error_index) );
}
/* complete mssing length in 'VarBindList' sequence ; 'VarBindList' tlv is located directly before varbind offset */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, 3, frame_size - request->outbound_varbind_offset);
OF_BUILD_EXEC( snmp_pbuf_stream_seek_abs(&(request->outbound_pbuf_stream), request->outbound_varbind_offset - 1 - 3) ); /* - type - length_len(fixed, see snmp_prepare_outbound_frame()) */
OF_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
pbuf_realloc(request->outbound_pbuf, frame_size);
snmp_stats.outgetresponses++;
snmp_stats.outpkts++;
return ERR_OK;
}
static err_t
snmp_append_outbound_varbind(struct snmp_request *request, struct snmp_varbind* varbind)
{
struct snmp_asn1_tlv tlv;
u8_t vb_len_len, oid_len_len, value_len_len;
u16_t vb_value_len, oid_value_len, value_value_len;
/* calculate required lengths */
snmp_asn1_enc_oid_cnt(varbind->oid.id, varbind->oid.len, &oid_value_len);
snmp_asn1_enc_length_cnt(oid_value_len, &oid_len_len);
if (varbind->value_len == 0) {
value_value_len = 0;
} else if (varbind->value_len & SNMP_GET_VALUE_RAW_DATA) {
value_value_len = varbind->value_len & (~SNMP_GET_VALUE_RAW_DATA);
} else {
switch (varbind->type)
{
case SNMP_ASN1_TYPE_INTEGER:
if (varbind->value_len != sizeof(s32_t)) {
return ERR_VAL;
}
snmp_asn1_enc_s32t_cnt(*((s32_t*)varbind->value) , &value_value_len);
break;
case SNMP_ASN1_TYPE_COUNTER:
case SNMP_ASN1_TYPE_GAUGE:
case SNMP_ASN1_TYPE_TIMETICKS:
if (varbind->value_len != sizeof(u32_t)) {
return ERR_VAL;
}
snmp_asn1_enc_u32t_cnt(*((u32_t*)varbind->value) , &value_value_len);
break;
case SNMP_ASN1_TYPE_OCTET_STRING:
case SNMP_ASN1_TYPE_IPADDR:
case SNMP_ASN1_TYPE_OPAQUE:
value_value_len = varbind->value_len;
break;
case SNMP_ASN1_TYPE_NULL:
if (varbind->value_len != 0) {
return ERR_VAL;
}
value_value_len = 0;
break;
case SNMP_ASN1_TYPE_OBJECT_ID:
if ((varbind->value_len % sizeof(u32_t)) != 0) {
return ERR_VAL;
}
snmp_asn1_enc_oid_cnt((u32_t*)varbind->value, varbind->value_len / sizeof(u32_t), &value_value_len);
break;
case SNMP_ASN1_TYPE_COUNTER64:
if (varbind->value_len != (2 * sizeof(u32_t))) {
return ERR_VAL;
}
snmp_asn1_enc_u64t_cnt((u32_t*)varbind->value , &value_value_len);
break;
default:
/* unsupported type */
return ERR_VAL;
}
}
snmp_asn1_enc_length_cnt(value_value_len, &value_len_len);
vb_value_len = 1 + oid_len_len + oid_value_len + 1 + value_len_len + value_value_len;
snmp_asn1_enc_length_cnt(vb_value_len, &vb_len_len);
/* check length already before adding first data because in case of GetBulk,
* data added so far is returned and therefore no partial data shall be added
*/
if ((1 + vb_len_len + vb_value_len) > request->outbound_pbuf_stream.length) {
return ERR_BUF;
}
/* 'VarBind' sequence */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_SEQUENCE, vb_len_len, vb_value_len);
OVB_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
/* VarBind OID */
SNMP_ASN1_SET_TLV_PARAMS(tlv, SNMP_ASN1_TYPE_OBJECT_ID, oid_len_len, oid_value_len);
OVB_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
OVB_BUILD_EXEC( snmp_asn1_enc_oid(&(request->outbound_pbuf_stream), varbind->oid.id, varbind->oid.len) );
/* VarBind value */
SNMP_ASN1_SET_TLV_PARAMS(tlv, varbind->type, value_len_len, value_value_len);
OVB_BUILD_EXEC( snmp_ans1_enc_tlv(&(request->outbound_pbuf_stream), &tlv) );
if (value_value_len > 0) {
if (varbind->value_len & SNMP_GET_VALUE_RAW_DATA) {
OVB_BUILD_EXEC( snmp_asn1_enc_raw(&(request->outbound_pbuf_stream), (u8_t*)varbind->value, value_value_len) );
} else {
switch (varbind->type)
{
case SNMP_ASN1_TYPE_INTEGER:
OVB_BUILD_EXEC( snmp_asn1_enc_s32t(&(request->outbound_pbuf_stream), value_value_len, *((s32_t*)varbind->value)) );
break;
case SNMP_ASN1_TYPE_COUNTER:
case SNMP_ASN1_TYPE_GAUGE:
case SNMP_ASN1_TYPE_TIMETICKS:
OVB_BUILD_EXEC( snmp_asn1_enc_u32t(&(request->outbound_pbuf_stream), value_value_len, *((u32_t*)varbind->value)) );
break;
case SNMP_ASN1_TYPE_OCTET_STRING:
case SNMP_ASN1_TYPE_IPADDR:
case SNMP_ASN1_TYPE_OPAQUE:
OVB_BUILD_EXEC( snmp_asn1_enc_raw(&(request->outbound_pbuf_stream), (u8_t*)varbind->value, value_value_len) );
value_value_len = varbind->value_len;
break;
case SNMP_ASN1_TYPE_OBJECT_ID:
OVB_BUILD_EXEC( snmp_asn1_enc_oid(&(request->outbound_pbuf_stream), (u32_t*)varbind->value, varbind->value_len / sizeof(u32_t)) );
break;
case SNMP_ASN1_TYPE_COUNTER64:
OVB_BUILD_EXEC( snmp_asn1_enc_u64t(&(request->outbound_pbuf_stream), value_value_len, (u32_t*)varbind->value) );
break;
default:
LWIP_ASSERT("Unknown variable type", 0);
break;
}
}
}
return ERR_OK;
}
