ngtcp2: Allow curl to send larger UDP datagrams #8883
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Allow curl to send larger UDP datagram if Path MTU Discovery finds the availability of larger path MTU. To make it work and not to send fragmented packet, we need to set DF bit. That makes send(2) fail with EMSGSIZE if UDP datagram is too large. In that case, just let it lost. This patch enables DF bit for Linux only.
bagder
reviewed
May 19, 2022
lib/vquic/ngtcp2.c
Outdated
| /* Send larger UDP datagram if we can set DF bit. */ | ||
| #if defined(__linux__) && defined(IP_MTU_DISCOVER) && \ | ||
| defined(IPV6_MTU_DISCOVER) | ||
| uint8_t out[1452]; |
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Shouldn't this value rather have an NGTCP2_-name as well?
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And maybe, since the smaller value is 1200 (right?), maybe you could just use the larger value unconditionally there and save the code from a complicated #ifdef setup?
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Fixed in 1c66f5b
NGTCP2_ name is now defined in ngtcp2 library header, and now always use larger buffer.
bagder
approved these changes
May 20, 2022
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Thanks! |
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Allow curl to send larger UDP datagram if Path MTU Discovery finds the
availability of larger path MTU. To make it work and not to send
fragmented packet, we need to set DF bit. That makes send(2) fail
with EMSGSIZE if UDP datagram is too large. In that case, just let it
lost. This patch enables DF bit for Linux only.