Bananymous
2f45349658
No need to swap bytes of every 16 bit word in the packet, we can just do one swap at the return
38 lines
869 B
C++
38 lines
869 B
C++
#include <kernel/Networking/NetworkLayer.h>
|
|
|
|
namespace Kernel
|
|
{
|
|
|
|
uint16_t calculate_internet_checksum(BAN::ConstByteSpan buffer)
|
|
{
|
|
return calculate_internet_checksum({ &buffer, 1 });
|
|
}
|
|
|
|
uint16_t calculate_internet_checksum(BAN::Span<const BAN::ConstByteSpan> buffers)
|
|
{
|
|
uint32_t checksum = 0;
|
|
|
|
for (size_t i = 0; i < buffers.size(); i++)
|
|
{
|
|
auto buffer = buffers[i];
|
|
|
|
const uint16_t* buffer_u16 = reinterpret_cast<const uint16_t*>(buffer.data());
|
|
for (size_t j = 0; j < buffer.size() / 2; j++)
|
|
checksum += buffer_u16[j];
|
|
|
|
if (buffer.size() % 2)
|
|
{
|
|
// NOTE: we only allow last buffer to be odd-length
|
|
ASSERT(i == buffers.size() - 1);
|
|
checksum += buffer[buffer.size() - 1];
|
|
}
|
|
}
|
|
|
|
while (checksum >> 16)
|
|
checksum = (checksum & 0xFFFF) + (checksum >> 16);
|
|
|
|
return BAN::host_to_network_endian<uint16_t>(~checksum);
|
|
}
|
|
|
|
}
|