| Message ID | 8a59f3bd9d43063f77c7b8db88f6722be44c6034.1635413715.git.lucien.xin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 40171248bb8934537fec8fbaf718e57c8add187c |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | sctp: a couple of fixes for PLPMTUD | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Series has a cover letter |
| netdev/fixes_present | success | Fixes tag present in non-next series |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 2 maintainers not CCed: nhorman@tuxdriver.com vyasevich@gmail.com |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Fixes tag looks correct |
| netdev/checkpatch | warning | WARNING: line length of 96 exceeds 80 columns |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | No static functions without inline keyword in header files |
diff --git a/net/sctp/output.c b/net/sctp/output.c index 4dfb5ea82b05..cdfdbd353c67 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -581,13 +581,16 @@ int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp) chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list); sk = chunk->skb->sk; - /* check gso */ if (packet->size > tp->pathmtu && !packet->ipfragok && !chunk->pmtu_probe) { - if (!sk_can_gso(sk)) { - pr_err_once("Trying to GSO but underlying device doesn't support it."); - goto out; + if (tp->pl.state == SCTP_PL_ERROR) { /* do IP fragmentation if in Error state */ + packet->ipfragok = 1; + } else { + if (!sk_can_gso(sk)) { /* check gso */ + pr_err_once("Trying to GSO but underlying device doesn't support it."); + goto out; + } + gso = 1; } - gso = 1; } /* alloc head skb */ diff --git a/net/sctp/transport.c b/net/sctp/transport.c index a3d3ca6dd63d..1f2dfad768d5 100644 --- a/net/sctp/transport.c +++ b/net/sctp/transport.c @@ -269,7 +269,7 @@ bool sctp_transport_pl_send(struct sctp_transport *t) if (t->pl.probe_size == SCTP_BASE_PLPMTU) { /* BASE_PLPMTU Confirmation Failed */ t->pl.state = SCTP_PL_ERROR; /* Base -> Error */ - t->pl.pmtu = SCTP_MIN_PLPMTU; + t->pl.pmtu = SCTP_BASE_PLPMTU; t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); sctp_assoc_sync_pmtu(t->asoc); } @@ -366,7 +366,7 @@ static bool sctp_transport_pl_toobig(struct sctp_transport *t, u32 pmtu) if (pmtu >= SCTP_MIN_PLPMTU && pmtu < SCTP_BASE_PLPMTU) { t->pl.state = SCTP_PL_ERROR; /* Base -> Error */ - t->pl.pmtu = SCTP_MIN_PLPMTU; + t->pl.pmtu = SCTP_BASE_PLPMTU; t->pathmtu = t->pl.pmtu + sctp_transport_pl_hlen(t); } } else if (t->pl.state == SCTP_PL_SEARCH) {
Currently when PLPMTUD enters Error state, transport pathmtu will be set to MIN_PLPMTU(512) while probe is continuing with BASE_PLPMTU(1200). It will cause pathmtu to stay in a very small value, even if the real pmtu is some value like 1000. RFC8899 doesn't clearly say how to set the value in Error state. But one possibility could be keep using BASE_PLPMTU for the real pmtu, but allow to do IP fragmentation when it's in Error state. As it says in rfc8899#section-5.4: Some paths could be unable to sustain packets of the BASE_PLPMTU size. The Error State could be implemented to provide robustness to such paths. This allows fallback to a smaller than desired PLPMTU rather than suffer connectivity failure. This could utilize methods such as endpoint IP fragmentation to enable the PL sender to communicate using packets smaller than the BASE_PLPMTU. This patch is to set pmtu to BASE_PLPMTU instead of MIN_PLPMTU for Error state in sctp_transport_pl_send/toobig(), and set packet ipfragok for non-probe packets when it's in Error state. Fixes: 1dc68c194571 ("sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path") Reported-by: Ying Xu <yinxu@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> --- net/sctp/output.c | 13 ++++++++----- net/sctp/transport.c | 4 ++-- 2 files changed, 10 insertions(+), 7 deletions(-)