tcp/dccp: Consolidate common code for RFC 3390 conversion

This patch consolidates initial-window code common to TCP and CCID-2:
 * TCP uses RFC 3390 in a packet-oriented manner (tcp_input.c) and
 * CCID-2 uses RFC 3390 in packet-oriented manner (RFC 4341).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gerrit Renker 2010-08-29 19:23:12 +00:00 committed by David S. Miller
parent d26eeb07fd
commit 22b71c8f4f
3 changed files with 19 additions and 21 deletions

View file

@ -779,6 +779,21 @@ static inline __u32 tcp_current_ssthresh(const struct sock *sk)
/* Use define here intentionally to get WARN_ON location shown at the caller */
#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
/*
* Convert RFC 3390 larger initial window into an equivalent number of packets.
*
* 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 a multiplier in the relevant range.
*/
static inline u32 rfc3390_bytes_to_packets(const u32 smss)
{
return smss <= 1095 ? 4 : (smss > 1460 ? 2 : 3);
}
extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);