Fixes unused MTU settings at TcpSocket dispatch #384
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This commit fixes a small bug, where the TcpSocket computed the maximum size per payload in a tx_buffer without taking into account the MTU defined by the underlying network device.
Dirbaio
requested changes
Oct 23, 2020
src/socket/tcp.rs
Outdated
| @@ -1558,7 +1558,8 @@ impl<'a> TcpSocket<'a> { | |||
| // Extract as much data as the remote side can receive in this packet | |||
| // from the transmit buffer. | |||
| let offset = self.remote_last_seq - self.local_seq_no; | |||
| let size = cmp::min(self.remote_win_len, self.remote_mss); | |||
| let size = cmp::min(cmp::min(self.remote_win_len, self.remote_mss), | |||
| caps.max_transmission_unit); | |||
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I'm not convinced this is correct. MTU is IP packet size (IP header + TCP header + payload). size here is only payload size.
You have to subtract the IP and TCP header sizes, as in here :
Line 1624 in 1268fb3
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Ah, so much for a quick fix on my part. Haha.
Is this fine?
let size = cmp::min(cmp::min(self.remote_win_len, self.remote_mss),
caps.max_transmission_unit - ip_repr.buffer_len() - repr.mss_header_len());
repr.payload = self.tx_buffer.get_allocated(offset, size);The MTU consists of TCP header, IP header and the payload. In the former fix, this was not taken into account.
Dirbaio
approved these changes
Oct 23, 2020
|
Thanks @mustermeiszer for the fix and @Dirbaio for the review! |
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This commit fixes a small bug, where the TcpSocket computed the maximum
size per payload in a tx_buffer without taking into account the MTU
defined by the underlying network device.