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TCP: Correct checksum for packets with odd number of bytes.

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This commit is contained in:
Andreas Kling 2019-03-14 19:57:54 +01:00
parent 4919b926f4
commit 5dfdcf796d
1 changed files with 2 additions and 1 deletions
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3
Kernel/TCPSocket.cpp
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@ -50,6 +50,7 @@ int TCPSocket::protocol_receive(const ByteBuffer& packet_buffer, void* buffer, s
auto& ipv4_packet = *(const IPv4Packet*)(packet_buffer.pointer());
auto& tcp_packet = *static_cast<const TCPPacket*>(ipv4_packet.payload());
size_t payload_size = packet_buffer.size() - sizeof(IPv4Packet) - tcp_packet.header_size();
kprintf("payload_size %u, will it fit in %u?\n", payload_size, buffer_size);
ASSERT(buffer_size >= payload_size);
if (addr) {
auto& ia = *(sockaddr_in*)addr;
@ -141,7 +142,7 @@ NetworkOrdered<word> TCPSocket::compute_tcp_checksum(const IPv4Address& source,
checksum = (checksum >> 16) + (checksum & 0xffff);
}
if (payload_size & 1) {
word expanded_byte = ((const byte*)packet.payload())[payload_size - 1];
word expanded_byte = ((const byte*)packet.payload())[payload_size - 1] << 8;
checksum += expanded_byte;
if (checksum > 0xffff)
checksum = (checksum >> 16) + (checksum & 0xffff);