/* Parse PDU header */
static AGENTX_ERR_CODE_E
pdu_hdr_parse(struct agentx_datagram *xdg, uint8_t **buffer)
{
AGENTX_ERR_CODE_E err;
uint8_t *buf;
err = AGENTX_ERR_OK;
buf = *buffer;
/* PDU header */
xdg->pdu_hdr.version = *buf++;
xdg->pdu_hdr.type = *buf++;
xdg->pdu_hdr.flags = *buf++;
xdg->pdu_hdr.reserved = *buf++;
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->pdu_hdr.session_id = NTOH32(*(uint32_t *)buf);
buf += sizeof(uint32_t);
xdg->pdu_hdr.transaction_id = NTOH32(*(uint32_t *)buf);
buf += sizeof(uint32_t);
xdg->pdu_hdr.packet_id = NTOH32(*(uint32_t *)buf);
buf += sizeof(uint32_t);
xdg->pdu_hdr.payload_length = NTOH32(*(uint32_t *)buf);
buf += sizeof(uint32_t);
} else {
xdg->pdu_hdr.session_id = *(uint32_t *)buf;
buf += sizeof(uint32_t);
xdg->pdu_hdr.transaction_id = *(uint32_t *)buf;
buf += sizeof(uint32_t);
xdg->pdu_hdr.packet_id = *(uint32_t *)buf;
buf += sizeof(uint32_t);
xdg->pdu_hdr.payload_length = *(uint32_t *)buf;
buf += sizeof(uint32_t);
}
/* Optinal context */
if (xdg->pdu_hdr.flags & NON_DEFAULT_CONTEXT) {
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->ctx_len = NTOH32(*(uint32_t *)buf);
} else {
xdg->ctx_len = *(uint32_t *)buf;
}
if (xdg->ctx_len + 1 > sizeof(xdg->context)) {
err = AGENTX_ERR_PDU_CTX_LEN;
*buffer = buf;
return err;
}
buf += sizeof(uint32_t);
memcpy(xdg->context, buf, xdg->ctx_len);
buf += uint_sizeof(xdg->ctx_len);
xdg->pdu_hdr.payload_length -= 4 + uint_sizeof(xdg->ctx_len);
}
/* additional data */
switch (xdg->pdu_hdr.type) {
case AGENTX_PDU_CLOSE:
xdg->u.close.reason = *buf;
buf += sizeof(uint32_t);
xdg->pdu_hdr.payload_length -= sizeof(uint32_t);
break;
case AGENTX_PDU_GETBULK:
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->u.getbulk.non_rep = NTOH16(*(uint16_t *)buf);
} else {
xdg->u.getbulk.non_rep = *(uint16_t *)buf;
}
buf += sizeof(uint16_t);
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->u.getbulk.max_rep = NTOH16(*(uint16_t *)buf);
} else {
xdg->u.getbulk.max_rep = *(uint16_t *)buf;
}
buf += sizeof(uint16_t);
xdg->pdu_hdr.payload_length -= 2 * sizeof(uint16_t);
break;
case AGENTX_PDU_RESPONSE:
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->u.response.sys_up_time = NTOH32(*(uint32_t *)buf);
} else {
xdg->u.response.sys_up_time = *(uint32_t *)buf;
}
buf += sizeof(uint32_t);
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->u.response.error = NTOH16(*(uint16_t *)buf);
} else {
xdg->u.response.error = *(uint16_t *)buf;
}
buf += sizeof(uint16_t);
xdg->u.response.index = *(uint16_t *)buf;
if (xdg->pdu_hdr.flags & NETWORD_BYTE_ORDER) {
xdg->u.response.index = NTOH16(*(uint16_t *)buf);
} else {
xdg->u.response.index = *(uint16_t *)buf;
}
buf += sizeof(uint16_t);
xdg->pdu_hdr.payload_length -= sizeof(uint32_t) + 2 * sizeof(uint16_t);
default:
break;
}
*buffer = buf;
return err;
}
/* Input: buffer, flag, value type;
* Output: value pointer
* Return: number of elements
*/
uint32_t
agentx_value_dec(uint8_t **buffer, uint8_t flag, uint8_t type, void *value)
{
uint8_t *buf;
uint32_t i, ret;
uint32_t *oid_src, *oid_dest;
uint32_t *inter_src, *inter_dest;
uint64_t *long_src, *long_dest;
buf = *buffer;
switch (type) {
case ASN1_TAG_INT:
case ASN1_TAG_CNT:
case ASN1_TAG_GAU:
case ASN1_TAG_TIMETICKS:
inter_src = (uint32_t *)buf;
inter_dest = (uint32_t *)value;
*inter_dest = *inter_src;
buf += sizeof(uint32_t);
ret = 1;
break;
case ASN1_TAG_CNT64:
long_src = (uint64_t *)buf;
long_dest = (uint64_t *)value;
*long_dest = *long_src;
buf += sizeof(uint64_t);
ret = 1;
break;
case ASN1_TAG_OCTSTR:
case ASN1_TAG_IPADDR:
ret = *(uint32_t *)buf;
buf += 4;
memcpy(value, buf, ret);
buf += uint_sizeof(ret);
break;
case ASN1_TAG_OBJID:
ret = *buf++;
uint8_t prefix = *buf++;
buf += 2;
if (ret == 0 && prefix == 0) {
break;
}
ret += 5;
oid_src = (uint32_t *)buf;
oid_dest = (uint32_t *)value;
oid_dest[0] = 1;
oid_dest[1] = 3;
oid_dest[2] = 6;
oid_dest[3] = 1;
oid_dest[4] = prefix;
for (i = 5; i < ret; i++) {
oid_dest[i] = oid_src[i - 5];
buf += sizeof(uint32_t);
}
break;
default:
ret = 0;
break;
}
*buffer = buf;
return ret;
}
