Common/Network: Make Build() methods const

This commit is contained in:
Sepalani 2022-07-10 20:12:07 +04:00
parent d902b04ae0
commit 5fdf255a2d
3 changed files with 46 additions and 44 deletions

View File

@ -355,34 +355,36 @@ TCPPacket::TCPPacket(const MACAddress& destination, const MACAddress& source,
{ {
} }
std::vector<u8> TCPPacket::Build() std::vector<u8> TCPPacket::Build() const
{ {
std::vector<u8> result; std::vector<u8> result;
result.reserve(Size()); result.reserve(Size()); // Useful not to invalidate .data() pointers
// recalc size // Copy data
ip_header.total_len = htons(static_cast<u16>(IPv4Header::SIZE + ipv4_options.size() +
TCPHeader::SIZE + tcp_options.size() + data.size()));
// copy data
InsertObj(&result, eth_header); InsertObj(&result, eth_header);
u8* const ip_ptr = result.data() + result.size();
InsertObj(&result, ip_header); InsertObj(&result, ip_header);
result.insert(result.end(), ipv4_options.begin(), ipv4_options.end()); result.insert(result.end(), ipv4_options.begin(), ipv4_options.end());
const std::size_t tcp_offset = result.size(); u8* const tcp_ptr = result.data() + result.size();
InsertObj(&result, tcp_header);
tcp_header.checksum = 0;
const u16 props = (ntohs(tcp_header.properties) & 0xfff) |
(static_cast<u16>((tcp_options.size() + TCPHeader::SIZE) & 0x3c) << 10);
tcp_header.properties = htons(props);
const u8* tcp_ptr = reinterpret_cast<const u8*>(&tcp_header);
result.insert(result.end(), tcp_ptr, tcp_ptr + TCPHeader::SIZE);
result.insert(result.end(), tcp_options.begin(), tcp_options.end()); result.insert(result.end(), tcp_options.begin(), tcp_options.end());
result.insert(result.end(), data.begin(), data.end()); result.insert(result.end(), data.begin(), data.end());
tcp_header.checksum = ComputeTCPNetworkChecksum( // Adjust size and checksum fields
ip_header.source_addr, ip_header.destination_addr, &result[tcp_offset], const u16 tcp_length = static_cast<u16>(TCPHeader::SIZE + tcp_options.size() + data.size());
static_cast<u16>(result.size() - tcp_offset), IPPROTO_TCP); const u16 tcp_properties =
std::copy(tcp_ptr, tcp_ptr + TCPHeader::SIZE, result.begin() + tcp_offset); (ntohs(tcp_header.properties) & 0xfff) |
(static_cast<u16>((tcp_options.size() + TCPHeader::SIZE) & 0x3c) << 10);
Common::BitCastPtr<u16>(tcp_ptr + offsetof(TCPHeader, properties)) = htons(tcp_properties);
const u16 ip_total_len = static_cast<u16>(IPv4Header::SIZE + ipv4_options.size() + tcp_length);
Common::BitCastPtr<u16>(ip_ptr + offsetof(IPv4Header, total_len)) = htons(ip_total_len);
auto checksum_bitcast_ptr = Common::BitCastPtr<u16>(tcp_ptr + offsetof(TCPHeader, checksum));
checksum_bitcast_ptr = u16(0);
checksum_bitcast_ptr = ComputeTCPNetworkChecksum(
ip_header.source_addr, ip_header.destination_addr, tcp_ptr, tcp_length, IPPROTO_TCP);
return result; return result;
} }
@ -401,31 +403,31 @@ UDPPacket::UDPPacket(const MACAddress& destination, const MACAddress& source,
{ {
} }
std::vector<u8> UDPPacket::Build() std::vector<u8> UDPPacket::Build() const
{ {
std::vector<u8> result; std::vector<u8> result;
result.reserve(Size()); result.reserve(Size()); // Useful not to invalidate .data() pointers
// recalc size // Copy data
ip_header.total_len = htons(
static_cast<u16>(IPv4Header::SIZE + ipv4_options.size() + UDPHeader::SIZE + data.size()));
udp_header.length = htons(static_cast<u16>(UDPHeader::SIZE + data.size()));
// copy data
InsertObj(&result, eth_header); InsertObj(&result, eth_header);
u8* const ip_ptr = result.data() + result.size();
InsertObj(&result, ip_header); InsertObj(&result, ip_header);
result.insert(result.end(), ipv4_options.begin(), ipv4_options.end()); result.insert(result.end(), ipv4_options.begin(), ipv4_options.end());
const std::size_t udp_offset = result.size(); u8* const udp_ptr = result.data() + result.size();
InsertObj(&result, udp_header);
udp_header.checksum = 0;
const u8* udp_ptr = reinterpret_cast<const u8*>(&udp_header);
result.insert(result.end(), udp_ptr, udp_ptr + UDPHeader::SIZE);
result.insert(result.end(), data.begin(), data.end()); result.insert(result.end(), data.begin(), data.end());
udp_header.checksum = ComputeTCPNetworkChecksum( // Adjust size and checksum fields
ip_header.source_addr, ip_header.destination_addr, &result[udp_offset], const u16 udp_length = static_cast<u16>(UDPHeader::SIZE + data.size());
static_cast<u16>(result.size() - udp_offset), IPPROTO_UDP); Common::BitCastPtr<u16>(udp_ptr + offsetof(UDPHeader, length)) = htons(udp_length);
std::copy(udp_ptr, udp_ptr + UDPHeader::SIZE, result.begin() + udp_offset);
const u16 ip_total_len = static_cast<u16>(IPv4Header::SIZE + ipv4_options.size() + udp_length);
Common::BitCastPtr<u16>(ip_ptr + offsetof(IPv4Header, total_len)) = htons(ip_total_len);
auto checksum_bitcast_ptr = Common::BitCastPtr<u16>(udp_ptr + offsetof(UDPHeader, checksum));
checksum_bitcast_ptr = u16(0);
checksum_bitcast_ptr = ComputeTCPNetworkChecksum(
ip_header.source_addr, ip_header.destination_addr, udp_ptr, udp_length, IPPROTO_UDP);
return result; return result;
} }

View File

@ -202,7 +202,7 @@ struct TCPPacket
TCPPacket(); TCPPacket();
TCPPacket(const MACAddress& destination, const MACAddress& source, const sockaddr_in& from, TCPPacket(const MACAddress& destination, const MACAddress& source, const sockaddr_in& from,
const sockaddr_in& to, u32 seq, u32 ack, u16 flags); const sockaddr_in& to, u32 seq, u32 ack, u16 flags);
std::vector<u8> Build(); std::vector<u8> Build() const;
u16 Size() const; u16 Size() const;
EthernetHeader eth_header; EthernetHeader eth_header;
@ -220,7 +220,7 @@ struct UDPPacket
UDPPacket(); UDPPacket();
UDPPacket(const MACAddress& destination, const MACAddress& source, const sockaddr_in& from, UDPPacket(const MACAddress& destination, const MACAddress& source, const sockaddr_in& from,
const sockaddr_in& to, const std::vector<u8>& payload); const sockaddr_in& to, const std::vector<u8>& payload);
std::vector<u8> Build(); std::vector<u8> Build() const;
u16 Size() const; u16 Size() const;
EthernetHeader eth_header; EthernetHeader eth_header;

View File

@ -142,7 +142,7 @@ void CEXIETHERNET::BuiltInBBAInterface::HandleDHCP(const Common::UDPPacket& pack
reply.AddOption(3, ip_part); // router ip reply.AddOption(3, ip_part); // router ip
reply.AddOption(255, {}); // end reply.AddOption(255, {}); // end
Common::UDPPacket response(bba_mac, m_fake_mac, from, to, reply.Build()); const Common::UDPPacket response(bba_mac, m_fake_mac, from, to, reply.Build());
WriteToQueue(response.Build()); WriteToQueue(response.Build());
} }
@ -179,8 +179,8 @@ StackRef* CEXIETHERNET::BuiltInBBAInterface::GetTCPSlot(u16 src_port, u16 dst_po
std::vector<u8> BuildFINFrame(StackRef* ref) std::vector<u8> BuildFINFrame(StackRef* ref)
{ {
Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num, const Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num,
ref->ack_num, TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_RST); ref->ack_num, TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_RST);
for (auto& tcp_buf : ref->tcp_buffers) for (auto& tcp_buf : ref->tcp_buffers)
tcp_buf.used = false; tcp_buf.used = false;
@ -189,8 +189,8 @@ std::vector<u8> BuildFINFrame(StackRef* ref)
std::vector<u8> BuildAckFrame(StackRef* ref) std::vector<u8> BuildAckFrame(StackRef* ref)
{ {
Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num, const Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num,
ref->ack_num, TCP_FLAG_ACK); ref->ack_num, TCP_FLAG_ACK);
return result.Build(); return result.Build();
} }
@ -498,7 +498,7 @@ std::optional<std::vector<u8>> TryGetDataFromSocket(StackRef* ref)
ref->from.sin_port = htons(remote_port); ref->from.sin_port = htons(remote_port);
ref->from.sin_addr.s_addr = htonl(ref->target.toInteger()); ref->from.sin_addr.s_addr = htonl(ref->target.toInteger());
const std::vector<u8> udp_data(buffer.begin(), buffer.begin() + datasize); const std::vector<u8> udp_data(buffer.begin(), buffer.begin() + datasize);
Common::UDPPacket packet(ref->bba_mac, ref->my_mac, ref->from, ref->to, udp_data); const Common::UDPPacket packet(ref->bba_mac, ref->my_mac, ref->from, ref->to, udp_data);
return packet.Build(); return packet.Build();
} }
break; break;