void DNS::skip_to_section_end(InputMemoryStream& stream,
const uint32_t num_records) const {
for (uint32_t i = 0; i < num_records; ++i) {
skip_to_dname_end(stream);
stream.skip(sizeof(uint16_t) * 2 + sizeof(uint32_t));
uint16_t data_size = stream.read_be<uint16_t>();
if (!stream.can_read(data_size)) {
throw malformed_packet();
}
stream.skip(data_size);
}
}
void Dot11::parse_tagged_parameters(InputMemoryStream& stream) {
if (stream) {
while (stream.size() >= 2) {
OptionTypes opcode = static_cast<OptionTypes>(stream.read<uint8_t>());
uint8_t length = stream.read<uint8_t>();
if (!stream.can_read(length)) {
throw malformed_packet();
}
add_tagged_option(opcode, length, stream.pointer());
stream.skip(length);
}
}
}
void try_parse_icmp_extensions(InputMemoryStream& stream,
uint32_t payload_length,
ICMPExtensionsStructure& extensions) {
if (!stream) {
return;
}
// Check if this is one of the types defined in RFC 4884
const uint32_t minimum_payload = ICMPExtensionsStructure::MINIMUM_ICMP_PAYLOAD;
// Check if we actually have this amount of data and whether it's more than
// the minimum encapsulated packet size
const uint8_t* extensions_ptr;
uint32_t extensions_size;
if (stream.can_read(payload_length) && payload_length >= minimum_payload) {
extensions_ptr = stream.pointer() + payload_length;
extensions_size = stream.size() - payload_length;
}
else if (stream.can_read(minimum_payload)) {
// This packet might be non-rfc compliant. In that case the length
// field can contain garbage.
extensions_ptr = stream.pointer() + minimum_payload;
extensions_size = stream.size() - minimum_payload;
}
else {
// No more special cases, this doesn't have extensions
return;
}
if (ICMPExtensionsStructure::validate_extensions(extensions_ptr, extensions_size)) {
extensions = ICMPExtensionsStructure(extensions_ptr, extensions_size);
stream.size(stream.size() - extensions_size);
}
}
void DNS::skip_to_dname_end(InputMemoryStream& stream) const {
while (stream) {
uint8_t value = stream.read<uint8_t>();
if (value == 0) {
// Found the ending null byte, we're done
break;
}
else {
if ((value & 0xc0)) {
// This is an offset label, skip the second byte and we're done
stream.skip(1);
break;
}
else {
// This is an actual label, skip its contents
stream.skip(value);
}
}
}
}
