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| author | David S. Miller <davem@sunset.davemloft.net> | 2007-08-24 22:21:50 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-08-26 18:35:36 -0700 |
| commit | 26722873a460703e319462afa7ebb8ed3a036c07 (patch) | |
| tree | d621eb098a252a8e91d74d635d33eb30ee05aa21 /net/ipv4/tcp_input.c | |
| parent | a96fb49be3dd2031f722bf32af6ed7db965b60f7 (diff) | |
| download | lwn-26722873a460703e319462afa7ebb8ed3a036c07.tar.gz lwn-26722873a460703e319462afa7ebb8ed3a036c07.zip | |
[TCP]: Describe tcp_init_cwnd() thoroughly in a comment.
People often get tripped up by this function and think that
it does not implemented the prescribed algorithms from
RFC2414 and RFC3390, even though it does.
So add a comment to head off such misunderstandings in the
future.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index f030435e0eb4..9785df37a65f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -755,7 +755,15 @@ void tcp_update_metrics(struct sock *sk) } } -/* Numbers are taken from RFC2414. */ +/* Numbers are taken from RFC3390. + * + * John Heffner states: + * + * The RFC specifies a window of no more than 4380 bytes + * unless 2*MSS > 4380. Reading the pseudocode in the RFC + * is a bit misleading because they use a clamp at 4380 bytes + * rather than use a multiplier in the relevant range. + */ __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst) { __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0); |