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8369640831
PLPMTUD will short-circuit the old process for icmp TOOBIG packets. This part is described in rfc8899#section-4.6.2 (PL_PTB_SIZE = PTB_SIZE - other_headers_len). Note that from rfc8899#section-5.2 State Machine, each case below is for some specific states only: a) PL_PTB_SIZE < MIN_PLPMTU || PL_PTB_SIZE >= PROBED_SIZE, discard it, for any state b) MIN_PLPMTU < PL_PTB_SIZE < BASE_PLPMTU, Base -> Error, for Base state c) BASE_PLPMTU <= PL_PTB_SIZE < PLPMTU, Search -> Base or Complete -> Base, for Search and Complete states. d) PLPMTU < PL_PTB_SIZE < PROBED_SIZE, set pl.probe_size to PL_PTB_SIZE then verify it, for Search state. The most important one is case d), which will help find the optimal fast during searching. Like when pathmtu = 1392 for SCTP over IPv4, the search will be (20 is iphdr_len): 1. probe with 1200 - 20 2. probe with 1232 - 20 3. probe with 1264 - 20 ... 7. probe with 1388 - 20 8. probe with 1420 - 20 When sending the probe with 1420 - 20, TOOBIG may come with PL_PTB_SIZE = 1392 - 20. Then it matches case d), and saves some rounds to try with the 1392 - 20 probe. But of course, PLPMTUD doesn't trust TOOBIG packets, and it will go back to the common searching once the probe with the new size can't be verified. Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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.. | ||
associola.c | ||
auth.c | ||
bind_addr.c | ||
chunk.c | ||
debug.c | ||
diag.c | ||
endpointola.c | ||
input.c | ||
inqueue.c | ||
ipv6.c | ||
Kconfig | ||
Makefile | ||
objcnt.c | ||
offload.c | ||
output.c | ||
outqueue.c | ||
primitive.c | ||
proc.c | ||
protocol.c | ||
sm_make_chunk.c | ||
sm_sideeffect.c | ||
sm_statefuns.c | ||
sm_statetable.c | ||
socket.c | ||
stream.c | ||
stream_interleave.c | ||
stream_sched.c | ||
stream_sched_prio.c | ||
stream_sched_rr.c | ||
sysctl.c | ||
transport.c | ||
tsnmap.c | ||
ulpevent.c | ||
ulpqueue.c |