diff options
| author | Gerrit Renker <gerrit@erg.abdn.ac.uk> | 2007-09-26 05:40:13 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-10-10 23:52:35 (GMT) |
| commit | 4c70f383e0c0273c4092c4efdb414be0966978b7 (patch) | |
| tree | 733cc2497ec68c74d42ed6d8f6978b24152a3de0 | |
| parent | aa97efd97acefb7d3dcd864adb878c7ce34061b3 (diff) | |
| download | linux-4c70f383e0c0273c4092c4efdb414be0966978b7.tar.xz | |
[DCCP]: Provide 10s of microsecond timesource
This provides a timesource, conveniently used for DCCP timestamps, which
returns the elapsed time in 10s of microseconds since initialisation.
This makes for a wrap-around time of about 11.9 hours, which should be
sufficient for most applications.
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/dccp/dccp.h | 2 | ||||
| -rw-r--r-- | net/dccp/options.c | 2 | ||||
| -rw-r--r-- | net/dccp/proto.c | 2 | ||||
| -rw-r--r-- | net/dccp/timer.c | 21 |
4 files changed, 26 insertions, 1 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index ddacc23..a75c740 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -396,6 +396,8 @@ extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb); extern int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb, u32 elapsed_time); +extern u32 dccp_timestamp(void); +extern void dccp_timestamping_init(void); extern int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb); extern int dccp_insert_option(struct sock *sk, struct sk_buff *skb, diff --git a/net/dccp/options.c b/net/dccp/options.c index 1674156..a57fcbd 100644 --- a/net/dccp/options.c +++ b/net/dccp/options.c @@ -372,7 +372,7 @@ EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb) { - __be32 now = htonl(((suseconds_t)ktime_to_us(ktime_get_real())) / 10); + __be32 now = htonl(dccp_timestamp()); /* yes this will overflow but that is the point as we want a * 10 usec 32 bit timer which mean it wraps every 11.9 hours */ diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 8d545da..14ec1d2 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -1076,6 +1076,8 @@ static int __init dccp_init(void) rc = dccp_sysctl_init(); if (rc) goto out_ackvec_exit; + + dccp_timestamping_init(); out: return rc; out_ackvec_exit: diff --git a/net/dccp/timer.c b/net/dccp/timer.c index 0197a41..3af0673 100644 --- a/net/dccp/timer.c +++ b/net/dccp/timer.c @@ -291,3 +291,24 @@ void dccp_init_xmit_timers(struct sock *sk) inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, &dccp_keepalive_timer); } + +static ktime_t dccp_timestamp_seed; +/** + * dccp_timestamp - 10s of microseconds time source + * Returns the number of 10s of microseconds since loading DCCP. This is native + * DCCP time difference format (RFC 4340, sec. 13). + * Please note: This will wrap around about circa every 11.9 hours. + */ +u32 dccp_timestamp(void) +{ + s64 delta = ktime_us_delta(ktime_get_real(), dccp_timestamp_seed); + + do_div(delta, 10); + return delta; +} +EXPORT_SYMBOL_GPL(dccp_timestamp); + +void __init dccp_timestamping_init(void) +{ + dccp_timestamp_seed = ktime_get_real(); +} |