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Kernel: Try to retransmit lost TCP packets

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Previously we didn't retransmit lost TCP packets which would cause
connections to hang if packets were lost. Also we now time out
TCP connections after a number of retransmission attempts.
This commit is contained in:
Gunnar Beutner 2021-05-13 10:49:10 +02:00 • committed by Andreas Kling
parent 9daec809b7
commit 08aa3a91e3
3 changed files with 101 additions and 16 deletions
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15
Kernel/Net/TCPSocket.h
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@ -93,6 +93,7 @@ public:
FINDuringConnect,
RSTDuringConnect,
UnexpectedFlagsDuringConnect,
RetransmitTimeout,
};
static const char* to_string(Error error)
@ -136,7 +137,6 @@ public:
KResult send_ack(bool allow_duplicate = false);
KResult send_tcp_packet(u16 flags, const UserOrKernelBuffer* = nullptr, size_t = 0);
void send_outgoing_packets(RoutingDecision&);
void receive_tcp_packet(const TCPPacket&, u16 size);
bool should_delay_next_ack() const;
@ -152,6 +152,9 @@ public:
void release_to_originator();
void release_for_accept(RefPtr<TCPSocket>);
static Lockable<HashTable<TCPSocket*>>& sockets_for_retransmit();
void retransmit_packets();
virtual KResult close() override;
protected:
@ -173,6 +176,10 @@ private:
virtual KResult protocol_bind() override;
virtual KResult protocol_listen() override;
void do_retransmit_packets();
void enqueue_for_retransmit();
void dequeue_for_retransmit();
WeakPtr<TCPSocket> m_originator;
HashMap<IPv4SocketTuple, NonnullRefPtr<TCPSocket>> m_pending_release_for_accept;
Direction m_direction { Direction::Unspecified };
@ -190,7 +197,6 @@ private:
u32 ack_number { 0 };
ByteBuffer buffer;
int tx_counter { 0 };
Time tx_time {};
};
Lock m_not_acked_lock { "TCPSocket unacked packets" };
@ -200,6 +206,11 @@ private:
u32 m_last_ack_number_sent { 0 };
Time m_last_ack_sent_time;
// FIXME: Make this configurable (sysctl)
static constexpr u32 maximum_retransmits = 5;
Time m_last_retransmit_time;
u32 m_retransmit_attempts { 0 };
};
}