Messages in this thread | | | Date | Mon, 25 Nov 2013 09:37:00 +0800 | From | Xufeng Zhang <> | Subject | Re: [PATCH] sctp: Restore 'resent' bit to avoid retransmitted chunks for RTT measurements |
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On 11/22/2013 10:18 PM, Vlad Yasevich wrote: > On 11/22/2013 03:30 AM, Xufeng Zhang wrote: > >> From: Signed-off-by: Xufeng Zhang<xufeng.zhang@windriver.com> >> >> Currently retransmitted DATA chunks could also be used for >> RTT measurements since there are no flag to identify whether >> the transmitted DATA chunk is a new one or a retransmitted one. >> This problem is introduced by commit ae19c5486 ("sctp: remove >> 'resent' bit from the chunk") which inappropriately removed the >> 'resent' bit completely, instead of doing this, we should set >> the resent bit only for the retransmitted DATA chunks. >> >> Signed-off-by: Xufeng Zhang<xufeng.zhang@windriver.com> >> --- >> include/net/sctp/structs.h | 1 + >> net/sctp/output.c | 23 +++++++++++++---------- >> net/sctp/outqueue.c | 3 +++ >> net/sctp/sm_make_chunk.c | 1 + >> 4 files changed, 18 insertions(+), 10 deletions(-) >> >> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h >> index 2174d8d..ea0ca5f 100644 >> --- a/include/net/sctp/structs.h >> +++ b/include/net/sctp/structs.h >> @@ -629,6 +629,7 @@ struct sctp_chunk { >> #define SCTP_NEED_FRTX 0x1 >> #define SCTP_DONT_FRTX 0x2 >> __u16 rtt_in_progress:1, /* This chunk used for RTT calc? */ >> + resent:1, /* Has this chunk ever been resent. */ >> has_tsn:1, /* Does this chunk have a TSN yet? */ >> has_ssn:1, /* Does this chunk have a SSN yet? */ >> singleton:1, /* Only chunk in the packet? */ >> diff --git a/net/sctp/output.c b/net/sctp/output.c >> index e650978..32c214d 100644 >> --- a/net/sctp/output.c >> +++ b/net/sctp/output.c >> @@ -467,17 +467,20 @@ int sctp_packet_transmit(struct sctp_packet *packet) >> list_for_each_entry_safe(chunk, tmp,&packet->chunk_list, list) { >> list_del_init(&chunk->list); >> if (sctp_chunk_is_data(chunk)) { >> - /* 6.3.1 C4) When data is in flight and when allowed >> - * by rule C5, a new RTT measurement MUST be made each >> - * round trip. Furthermore, new RTT measurements >> - * SHOULD be made no more than once per round-trip >> - * for a given destination transport address. >> - */ >> - >> - if (!tp->rto_pending) { >> - chunk->rtt_in_progress = 1; >> - tp->rto_pending = 1; >> + if (!chunk->resent) { >> + /* 6.3.1 C4) When data is in flight and when allowed >> + * by rule C5, a new RTT measurement MUST be made each >> + * round trip. Furthermore, new RTT measurements >> + * SHOULD be made no more than once per round-trip >> + * for a given destination transport address. >> + */ >> + >> + if (!tp->rto_pending) { >> > Could be combined as > if (!chunk->resent&& !tp->rto_pending) { >
Got it!
> >> + chunk->rtt_in_progress = 1; >> + tp->rto_pending = 1; >> + } >> } >> + >> has_data = 1; >> } >> >> diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c >> index 94df758..70f4f56 100644 >> --- a/net/sctp/outqueue.c >> +++ b/net/sctp/outqueue.c >> @@ -446,6 +446,8 @@ void sctp_retransmit_mark(struct sctp_outq *q, >> transport->rto_pending = 0; >> } >> >> + chunk->resent = 1; >> + >> /* Move the chunk to the retransmit queue. The chunks >> * on the retransmit queue are always kept in order. >> */ >> @@ -1375,6 +1377,7 @@ static void sctp_check_transmitted(struct sctp_outq *q, >> * instance). >> */ >> if (!tchunk->tsn_gap_acked&& >> + !tchunk->resent&& >> tchunk->rtt_in_progress) { >> tchunk->rtt_in_progress = 0; >> rtt = jiffies - tchunk->sent_at; >> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c >> index fe69032..8fe89f8 100644 >> --- a/net/sctp/sm_make_chunk.c >> +++ b/net/sctp/sm_make_chunk.c >> @@ -1321,6 +1321,7 @@ struct sctp_chunk *sctp_chunkify(struct sk_buff *skb, >> INIT_LIST_HEAD(&retval->list); >> retval->skb = skb; >> retval->asoc = (struct sctp_association *)asoc; >> + retval->resent = 0; >> > Not needed due to zeroed out malloc. >
Thank you! Will send V2 later.
Thanks, Xufeng
> -vlad > > >> retval->singleton = 1; >> >> retval->fast_retransmit = SCTP_CAN_FRTX; >> >> > >
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