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Kernel: Send Fragmented IPv4 packets if payload size > mtu

This adds IPv4 fragmentation, so now we can send huuuuuuge packets
properly.
This commit is contained in:
AnotherTest 2020-04-02 05:57:49 +04:30 committed by Andreas Kling
parent 592f218151
commit b3d7c5d9de
3 changed files with 70 additions and 2 deletions

View file

@ -40,6 +40,11 @@ enum class IPv4Protocol : u16 {
UDP = 17,
};
enum class IPv4PacketFlags : u16 {
DontFragment = 0x4000,
MoreFragments = 0x2000,
};
NetworkOrdered<u16> internet_checksum(const void*, size_t);
class [[gnu::packed]] IPv4Packet
@ -75,6 +80,28 @@ public:
void* payload() { return this + 1; }
const void* payload() const { return this + 1; }
u16 flags_and_fragment() const { return m_flags_and_fragment; }
u16 fragment_offset() const { return ((u16)m_flags_and_fragment & 0x2fff); }
u16 flags() const { return (((u16)m_flags_and_fragment) & (((u16)IPv4PacketFlags::MoreFragments) | ((u16)IPv4PacketFlags::DontFragment))); }
void set_has_more_fragments(bool more_fragments)
{
if (more_fragments)
m_flags_and_fragment = (u16)m_flags_and_fragment | ((u16)IPv4PacketFlags::MoreFragments);
else
m_flags_and_fragment = (u16)m_flags_and_fragment & ((u16)IPv4PacketFlags::MoreFragments);
}
void set_fragment_offset(u16 offset)
{
m_flags_and_fragment = flags() | (offset & 0x2fff);
}
bool is_a_fragment() const
{
// either has More-Fragments set, or has a fragment offset
return (((u16)m_flags_and_fragment) & ((u16)IPv4PacketFlags::MoreFragments)) || ((u16)m_flags_and_fragment & 0x2fff);
}
u16 payload_size() const { return m_length - sizeof(IPv4Packet); }
NetworkOrdered<u16> compute_checksum() const
@ -97,6 +124,7 @@ private:
};
static_assert(sizeof(IPv4Packet) == 20);
const LogStream& operator<<(const LogStream& stream, const IPv4Packet& packet);
inline NetworkOrdered<u16> internet_checksum(const void* ptr, size_t count)
{