packet_t *packet_parse(uint8_t *data, size_t length, options_t options)
{
packet_t *packet = (packet_t*) safe_malloc(sizeof(packet_t));
buffer_t *buffer = buffer_create_with_data(BO_BIG_ENDIAN, data, length);
/* Validate the size */
if(buffer_get_length(buffer) > MAX_PACKET_SIZE)
{
LOG_FATAL("Packet is too long: %zu bytes\n", buffer_get_length(buffer));
exit(1);
}
packet->packet_id = buffer_read_next_int16(buffer);
packet->packet_type = (packet_type_t) buffer_read_next_int8(buffer);
packet->session_id = buffer_read_next_int16(buffer);
switch(packet->packet_type)
{
case PACKET_TYPE_SYN:
packet->body.syn.seq = buffer_read_next_int16(buffer);
packet->body.syn.options = buffer_read_next_int16(buffer);
break;
case PACKET_TYPE_MSG:
if(options & OPT_CHUNKED_DOWNLOAD)
{
packet->body.msg.options.chunked.chunk = buffer_read_next_int32(buffer);
}
else
{
packet->body.msg.options.normal.seq = buffer_read_next_int16(buffer);
packet->body.msg.options.normal.ack = buffer_read_next_int16(buffer);
}
packet->body.msg.data = buffer_read_remaining_bytes(buffer, &packet->body.msg.data_length, -1, FALSE);
break;
case PACKET_TYPE_FIN:
packet->body.fin.reason = buffer_alloc_next_ntstring(buffer);
break;
case PACKET_TYPE_PING:
packet->body.ping.data = buffer_alloc_next_ntstring(buffer);
break;
default:
LOG_FATAL("Error: unknown message type (0x%02x)\n", packet->packet_type);
exit(0);
}
buffer_destroy(buffer);
return packet;
}
/* Read data from the session that will be sent out across the network. This
* will return up to read_length bytes (and will return the number of bytes
* read in read_length as well). The memory returned has to be freed.
*
* If the session isn't found, NULL is returned. If no data is waiting, the
* empty string is returned and read_length is set to 0.
*/
uint8_t *session_read(sessions_t *sessions, char *session_name, uint32_t *read_length)
{
uint32_t i = 0;
buffer_t *incoming;
buffer_t *response;
session_t *session;
session = session_get(sessions, session_name);
if(!session)
return NULL;
if(session_is_closed(sessions, session_name))
return NULL;
if(buffer_can_read_int8(sessions->buffer_data))
{
incoming = sessions->buffer_data;
}
else
{
if(!session)
return NULL;
incoming = session->buffer;
}
response = buffer_create(BO_NETWORK);
while(buffer_can_read_int8(incoming) && i < *read_length)
{
if(sessions->log)
fputc(buffer_peek_next_int8(incoming), sessions->log);
buffer_add_int8(response, buffer_read_next_int8(incoming));
i++;
}
/* Clear whichever buffer we're using if we're at the end. */
if(!buffer_can_read_int8(incoming))
buffer_clear(incoming);
return buffer_create_string_and_destroy(response, read_length);
}
static SELECT_RESPONSE_t recv_socket_callback(void *group, int s, uint8_t *data, size_t length, char *addr, uint16_t port, void *param)
{
/*driver_dns_t *driver_dns = param;*/
dns_t *dns = dns_create_from_packet(data, length);
driver_dns_t *driver = (driver_dns_t*) param;
LOG_INFO("DNS response received (%d bytes)", length);
/* TODO */
if(dns->rcode != _DNS_RCODE_SUCCESS)
{
/* TODO: Handle errors more gracefully */
switch(dns->rcode)
{
case _DNS_RCODE_FORMAT_ERROR:
LOG_ERROR("DNS: RCODE_FORMAT_ERROR");
break;
case _DNS_RCODE_SERVER_FAILURE:
LOG_ERROR("DNS: RCODE_SERVER_FAILURE");
break;
case _DNS_RCODE_NAME_ERROR:
LOG_ERROR("DNS: RCODE_NAME_ERROR");
break;
case _DNS_RCODE_NOT_IMPLEMENTED:
LOG_ERROR("DNS: RCODE_NOT_IMPLEMENTED");
break;
case _DNS_RCODE_REFUSED:
LOG_ERROR("DNS: RCODE_REFUSED");
break;
default:
LOG_ERROR("DNS: Unknown error code (0x%04x)", dns->rcode);
break;
}
}
else if(dns->question_count != 1)
{
LOG_ERROR("DNS returned the wrong number of response fields (question_count should be 1, was instead %d).", dns->question_count);
LOG_ERROR("This is probably due to a DNS error");
}
else if(dns->answer_count < 1)
{
LOG_ERROR("DNS didn't return an answer");
LOG_ERROR("This is probably due to a DNS error");
}
else
{
size_t i;
uint8_t *answer = NULL;
size_t answer_length = 0;
dns_type_t type = dns->answers[0].type;
if(type == _DNS_TYPE_TEXT)
{
/* Get the answer. */
answer = dns->answers[0].answer->TEXT.text;
answer_length = dns->answers[0].answer->TEXT.length;
LOG_INFO("Received a TXT response (%zu bytes)", answer_length);
/* Decode it. */
answer = buffer_decode_hex(answer, &answer_length);
}
else if(type == _DNS_TYPE_CNAME)
{
/* Get the answer. */
answer = remove_domain((char*)dns->answers[0].answer->CNAME.name, driver->domain);
answer_length = strlen((char*)answer);
LOG_INFO("Received a CNAME response (%zu bytes)", answer_length);
/* Decode it. */
answer = buffer_decode_hex(answer, &answer_length);
}
else if(type == _DNS_TYPE_MX)
{
/* Get the answer. */
answer = remove_domain((char*)dns->answers[0].answer->MX.name, driver->domain);
answer_length = strlen((char*)answer);
LOG_INFO("Received a MX response (%zu bytes)", answer_length);
/* Decode it. */
answer = buffer_decode_hex(answer, &answer_length);
}
else if(type == _DNS_TYPE_A)
{
buffer_t *buf = buffer_create(BO_BIG_ENDIAN);
qsort(dns->answers, dns->answer_count, sizeof(answer_t), cmpfunc_a);
for(i = 0; i < dns->answer_count; i++)
buffer_add_bytes(buf, dns->answers[i].answer->A.bytes + 1, 3);
answer_length = buffer_read_next_int8(buf);
LOG_INFO("Received an A response (%zu bytes)", answer_length);
answer = safe_malloc(answer_length);
buffer_read_bytes_at(buf, 1, answer, answer_length);
}
#ifndef WIN32
else if(type == _DNS_TYPE_AAAA)
{
buffer_t *buf = buffer_create(BO_BIG_ENDIAN);
qsort(dns->answers, dns->answer_count, sizeof(answer_t), cmpfunc_aaaa);
for(i = 0; i < dns->answer_count; i++)
buffer_add_bytes(buf, dns->answers[i].answer->AAAA.bytes + 1, 15);
answer_length = buffer_read_next_int8(buf);
LOG_INFO("Received an AAAA response (%zu bytes)", answer_length);
answer = safe_malloc(answer_length);
buffer_read_bytes_at(buf, 1, answer, answer_length);
}
#endif
else
{
LOG_ERROR("Unknown DNS type returned: %d", type);
answer = NULL;
}
if(answer)
{
/*LOG_WARNING("Received a %zu-byte DNS response: %s [0x%04x]", answer_length, answer, type);*/
/* Pass the buffer to the caller */
if(answer_length > 0)
{
/* Pass the data elsewhere. */
message_post_packet_in(answer, answer_length);
}
safe_free(answer);
}
}
dns_destroy(dns);
return SELECT_OK;
}
