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LibDNS: Prefer spans over raw pointers when parsing DNS packets

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This means we don't have to keep track of the pointer and size
separately.
This commit is contained in:
Tim Ledbetter 2023-11-02 20:04:11 +00:00 • committed by Andreas Kling
parent c1d7a51391
commit 4e3b59a4bb
7 changed files with 23 additions and 25 deletions
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22
Userland/Libraries/LibDNS/Packet.cpp
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@ -97,14 +97,14 @@ private:
static_assert(sizeof(DNSRecordWithoutName) == 10);
Optional<Packet> Packet::from_raw_packet(u8 const* raw_data, size_t raw_size)
Optional<Packet> Packet::from_raw_packet(ReadonlyBytes bytes)
{
if (raw_size < sizeof(PacketHeader)) {
dbgln("DNS response not large enough ({} out of {}) to be a DNS packet.", raw_size, sizeof(PacketHeader));
if (bytes.size() < sizeof(PacketHeader)) {
dbgln("DNS response not large enough ({} out of {}) to be a DNS packet.", bytes.size(), sizeof(PacketHeader));
return {};
}
auto& header = *(PacketHeader const*)(raw_data);
auto const& header = *bit_cast<PacketHeader const*>(bytes.data());
dbgln_if(LOOKUPSERVER_DEBUG, "Got packet (ID: {})", header.id());
dbgln_if(LOOKUPSERVER_DEBUG, " Question count: {}", header.question_count());
dbgln_if(LOOKUPSERVER_DEBUG, " Answer count: {}", header.answer_count());
@ -123,12 +123,12 @@ Optional<Packet> Packet::from_raw_packet(u8 const* raw_data, size_t raw_size)
size_t offset = sizeof(PacketHeader);
for (u16 i = 0; i < header.question_count(); i++) {
auto name = Name::parse(raw_data, offset, raw_size);
auto name = Name::parse(bytes, offset);
struct RawDNSAnswerQuestion {
NetworkOrdered<u16> record_type;
NetworkOrdered<u16> class_code;
};
auto& record_and_class = *(RawDNSAnswerQuestion const*)&raw_data[offset];
auto const& record_and_class = *bit_cast<RawDNSAnswerQuestion const*>(bytes.offset_pointer(offset));
u16 class_code = record_and_class.class_code & ~MDNS_WANTS_UNICAST_RESPONSE;
bool mdns_wants_unicast_response = record_and_class.class_code & MDNS_WANTS_UNICAST_RESPONSE;
packet.m_questions.empend(name, (RecordType)(u16)record_and_class.record_type, (RecordClass)class_code, mdns_wants_unicast_response);
@ -138,18 +138,16 @@ Optional<Packet> Packet::from_raw_packet(u8 const* raw_data, size_t raw_size)
}
for (u16 i = 0; i < header.answer_count(); ++i) {
auto name = Name::parse(raw_data, offset, raw_size);
auto& record = *(DNSRecordWithoutName const*)(&raw_data[offset]);
auto name = Name::parse(bytes, offset);
auto const& record = *bit_cast<DNSRecordWithoutName const*>(bytes.offset_pointer(offset));
offset += sizeof(DNSRecordWithoutName);
DeprecatedString data;
offset += sizeof(DNSRecordWithoutName);
switch ((RecordType)record.type()) {
case RecordType::PTR: {
size_t dummy_offset = offset;
data = Name::parse(raw_data, dummy_offset, raw_size).as_string();
data = Name::parse(bytes, dummy_offset).as_string();
break;
}
case RecordType::CNAME: