| Message ID | 08344e5d9b0eb31c1b777f44cd1b95ecdde5a3d6.1624549642.git.lucien.xin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | sctp: make the PLPMTUD probe more effective and efficient | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 2 maintainers not CCed: vyasevich@gmail.com nhorman@tuxdriver.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 60 this patch: 60 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | warning | WARNING: line length of 82 exceeds 80 columns WARNING: line length of 83 exceeds 80 columns |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 59 this patch: 59 |
| netdev/header_inline | success | Link |
On Thu, Jun 24, 2021 at 11:48:08AM -0400, Xin Long wrote: > @@ -333,13 +328,15 @@ void sctp_transport_pl_recv(struct sctp_transport *t) > t->pl.probe_size += SCTP_PL_MIN_STEP; > if (t->pl.probe_size >= t->pl.probe_high) { > t->pl.probe_high = 0; > + t->pl.raise_count = 0; > t->pl.state = SCTP_PL_COMPLETE; /* Search -> Search Complete */ > > t->pl.probe_size = t->pl.pmtu; > t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); > sctp_assoc_sync_pmtu(t->asoc); > } > - } else if (t->pl.state == SCTP_PL_COMPLETE) { > + } else if (t->pl.state == SCTP_PL_COMPLETE && ++t->pl.raise_count == 30) { Please either break the condition into 2 lines or even in 2 if()s. The ++ operator here can easily go unnoticed otherwise. > + /* Raise probe_size again after 30 * interval in Search Complete */ > t->pl.state = SCTP_PL_SEARCH; /* Search Complete -> Search */ > t->pl.probe_size += SCTP_PL_MIN_STEP; > } > -- > 2.27.0 >
On Thu, Jun 24, 2021 at 9:11 PM Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> wrote: > > On Thu, Jun 24, 2021 at 11:48:08AM -0400, Xin Long wrote: > > @@ -333,13 +328,15 @@ void sctp_transport_pl_recv(struct sctp_transport *t) > > t->pl.probe_size += SCTP_PL_MIN_STEP; > > if (t->pl.probe_size >= t->pl.probe_high) { > > t->pl.probe_high = 0; > > + t->pl.raise_count = 0; > > t->pl.state = SCTP_PL_COMPLETE; /* Search -> Search Complete */ > > > > t->pl.probe_size = t->pl.pmtu; > > t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); > > sctp_assoc_sync_pmtu(t->asoc); > > } > > - } else if (t->pl.state == SCTP_PL_COMPLETE) { > > + } else if (t->pl.state == SCTP_PL_COMPLETE && ++t->pl.raise_count == 30) { > > Please either break the condition into 2 lines or even in 2 if()s. The > ++ operator here can easily go unnoticed otherwise. will change it to: } else if (t->pl.state == SCTP_PL_COMPLETE) { t->pl.raise_count++; if (t->pl.raise_count == 30) { Thanks. > > > + /* Raise probe_size again after 30 * interval in Search Complete */ > > t->pl.state = SCTP_PL_SEARCH; /* Search Complete -> Search */ > > t->pl.probe_size += SCTP_PL_MIN_STEP; > > } > > -- > > 2.27.0 > >
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 9eaa701cda23..c4a4c1754be8 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -987,7 +987,8 @@ struct sctp_transport { __u16 pmtu; __u16 probe_size; __u16 probe_high; - __u8 probe_count; + __u8 probe_count:3; + __u8 raise_count:5; __u8 state; } pl; /* plpmtud related */ diff --git a/net/sctp/transport.c b/net/sctp/transport.c index f27b856ea8ce..5f23804f21c7 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -213,15 +213,10 @@ void sctp_transport_reset_reconf_timer(struct sctp_transport *transport) void sctp_transport_reset_probe_timer(struct sctp_transport *transport) { - int scale = 1; - if (timer_pending(&transport->probe_timer)) return; - if (transport->pl.state == SCTP_PL_COMPLETE && - transport->pl.probe_count == 1) - scale = 30; /* works as PMTU_RAISE_TIMER */ if (!mod_timer(&transport->probe_timer, - jiffies + transport->probe_interval * scale)) + jiffies + transport->probe_interval)) sctp_transport_hold(transport); } @@ -333,13 +328,15 @@ void sctp_transport_pl_recv(struct sctp_transport *t) t->pl.probe_size += SCTP_PL_MIN_STEP; if (t->pl.probe_size >= t->pl.probe_high) { t->pl.probe_high = 0; + t->pl.raise_count = 0; t->pl.state = SCTP_PL_COMPLETE; /* Search -> Search Complete */ t->pl.probe_size = t->pl.pmtu; t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); sctp_assoc_sync_pmtu(t->asoc); } - } else if (t->pl.state == SCTP_PL_COMPLETE) { + } else if (t->pl.state == SCTP_PL_COMPLETE && ++t->pl.raise_count == 30) { + /* Raise probe_size again after 30 * interval in Search Complete */ t->pl.state = SCTP_PL_SEARCH; /* Search Complete -> Search */ t->pl.probe_size += SCTP_PL_MIN_STEP; }
Currently the PLPMUTD probe will stop for a long period (interval * 30) after it enters search complete state. If there's a pmtu change on the route path, it takes a long time to be aware if the ICMP TooBig packet is lost or filtered. As it says in rfc8899#section-4.3: "A DPLPMTUD method MUST NOT rely solely on this method." (ICMP PTB message). This patch is to enable the other method for search complete state: "A PL can use the DPLPMTUD probing mechanism to periodically generate probe packets of the size of the current PLPMTU." With this patch, the probe will continue with the current pmtu every 'interval' until the PMTU_RAISE_TIMER 'timeout', which we implement by adding raise_count to raise the probe size when it counts to 30 and removing the SCTP_PL_COMPLETE check for PMTU_RAISE_TIMER. Signed-off-by: Xin Long <lucien.xin@gmail.com> --- include/net/sctp/structs.h | 3 ++- net/sctp/transport.c | 11 ++++------- 2 files changed, 6 insertions(+), 8 deletions(-)