git: 2de2ae331be2 - main - sctp: improve sctp_pathmtu_adjustment()
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Date: Thu, 30 Dec 2021 14:19:35 UTC
The branch main has been updated by tuexen:
URL: https://cgit.FreeBSD.org/src/commit/?id=2de2ae331be2504d1038b2124e7d44f23aa70405
commit 2de2ae331be2504d1038b2124e7d44f23aa70405
Author: Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2021-12-30 14:16:05 +0000
Commit: Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2021-12-30 14:16:05 +0000
sctp: improve sctp_pathmtu_adjustment()
Allow the resending of DATA chunks to be controlled by the caller,
which allows retiring sctp_mtu_size_reset() in a separate commit.
Also improve the computaion of the overhead and use 32-bit integers
consistently.
Thanks to Timo Voelker for pointing me to the code.
MFC after: 3 days
---
sys/netinet/sctp_input.c | 6 ++---
sys/netinet/sctp_pcb.c | 2 +-
sys/netinet/sctp_usrreq.c | 62 ++++++++++++++++++++++++++++-----------------
sys/netinet/sctp_var.h | 2 +-
sys/netinet6/sctp6_usrreq.c | 2 +-
5 files changed, 45 insertions(+), 29 deletions(-)
diff --git a/sys/netinet/sctp_input.c b/sys/netinet/sctp_input.c
index bdb126cbb50f..ef1b44c4a3ff 100644
--- a/sys/netinet/sctp_input.c
+++ b/sys/netinet/sctp_input.c
@@ -5291,7 +5291,7 @@ sctp_common_input_processing(struct mbuf **mm, int iphlen, int offset, int lengt
/* UDP encapsulation turned on. */
net->mtu -= sizeof(struct udphdr);
if (stcb->asoc.smallest_mtu > net->mtu) {
- sctp_pathmtu_adjustment(stcb, net->mtu);
+ sctp_pathmtu_adjustment(stcb, net->mtu, true);
}
} else if (port == 0) {
/* UDP encapsulation turned off. */
@@ -5331,7 +5331,7 @@ sctp_common_input_processing(struct mbuf **mm, int iphlen, int offset, int lengt
/* UDP encapsulation turned on. */
net->mtu -= sizeof(struct udphdr);
if (stcb->asoc.smallest_mtu > net->mtu) {
- sctp_pathmtu_adjustment(stcb, net->mtu);
+ sctp_pathmtu_adjustment(stcb, net->mtu, true);
}
} else if (port == 0) {
/* UDP encapsulation turned off. */
@@ -5426,7 +5426,7 @@ sctp_common_input_processing(struct mbuf **mm, int iphlen, int offset, int lengt
/* UDP encapsulation turned on. */
net->mtu -= sizeof(struct udphdr);
if (stcb->asoc.smallest_mtu > net->mtu) {
- sctp_pathmtu_adjustment(stcb, net->mtu);
+ sctp_pathmtu_adjustment(stcb, net->mtu, true);
}
} else if (port == 0) {
/* UDP encapsulation turned off. */
diff --git a/sys/netinet/sctp_pcb.c b/sys/netinet/sctp_pcb.c
index 7ad651ec377f..b7fce09fc661 100644
--- a/sys/netinet/sctp_pcb.c
+++ b/sys/netinet/sctp_pcb.c
@@ -4025,7 +4025,7 @@ sctp_add_remote_addr(struct sctp_tcb *stcb, struct sockaddr *newaddr,
stcb->asoc.smallest_mtu = net->mtu;
}
if (stcb->asoc.smallest_mtu > net->mtu) {
- sctp_pathmtu_adjustment(stcb, net->mtu);
+ sctp_pathmtu_adjustment(stcb, net->mtu, true);
}
#ifdef INET6
if (newaddr->sa_family == AF_INET6) {
diff --git a/sys/netinet/sctp_usrreq.c b/sys/netinet/sctp_usrreq.c
index bb84d3b7083f..e30d02dc9de1 100644
--- a/sys/netinet/sctp_usrreq.c
+++ b/sys/netinet/sctp_usrreq.c
@@ -104,35 +104,51 @@ VNET_SYSUNINIT(sctp, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH, sctp_finish, NULL);
#endif
void
-sctp_pathmtu_adjustment(struct sctp_tcb *stcb, uint16_t nxtsz)
+sctp_pathmtu_adjustment(struct sctp_tcb *stcb, uint32_t mtu, bool resend)
{
+ struct sctp_association *asoc;
struct sctp_tmit_chunk *chk;
- uint16_t overhead;
-
- /* Adjust that too */
- stcb->asoc.smallest_mtu = nxtsz;
- /* now off to subtract IP_DF flag if needed */
- overhead = IP_HDR_SIZE + sizeof(struct sctphdr);
- if (sctp_auth_is_required_chunk(SCTP_DATA, stcb->asoc.peer_auth_chunks)) {
- overhead += sctp_get_auth_chunk_len(stcb->asoc.peer_hmac_id);
+ uint32_t overhead;
+
+ asoc = &stcb->asoc;
+ KASSERT(mtu < asoc->smallest_mtu,
+ ("Currently only reducing association MTU %u supported (MTU %u)",
+ asoc->smallest_mtu, mtu));
+ asoc->smallest_mtu = mtu;
+ if (stcb->sctp_ep->sctp_flags & SCTP_PCB_FLAGS_BOUND_V6) {
+ overhead = SCTP_MIN_OVERHEAD;
+ } else {
+ overhead = SCTP_MIN_V4_OVERHEAD;
+ }
+ if (asoc->idata_supported) {
+ if (sctp_auth_is_required_chunk(SCTP_IDATA, asoc->peer_auth_chunks)) {
+ overhead += sctp_get_auth_chunk_len(asoc->peer_hmac_id);
+ }
+ } else {
+ if (sctp_auth_is_required_chunk(SCTP_DATA, asoc->peer_auth_chunks)) {
+ overhead += sctp_get_auth_chunk_len(asoc->peer_hmac_id);
+ }
}
- TAILQ_FOREACH(chk, &stcb->asoc.send_queue, sctp_next) {
- if ((chk->send_size + overhead) > nxtsz) {
+ KASSERT(overhead % 4 == 0,
+ ("overhead (%u) not a multiple of 4", overhead));
+ TAILQ_FOREACH(chk, &asoc->send_queue, sctp_next) {
+ if (((uint32_t)chk->send_size + overhead) > mtu) {
chk->flags |= CHUNK_FLAGS_FRAGMENT_OK;
}
}
- TAILQ_FOREACH(chk, &stcb->asoc.sent_queue, sctp_next) {
- if ((chk->send_size + overhead) > nxtsz) {
- /*
- * For this guy we also mark for immediate resend
- * since we sent to big of chunk
- */
+ TAILQ_FOREACH(chk, &asoc->sent_queue, sctp_next) {
+ if (((uint32_t)chk->send_size + overhead) > mtu) {
chk->flags |= CHUNK_FLAGS_FRAGMENT_OK;
- if (chk->sent < SCTP_DATAGRAM_RESEND) {
+ if (resend && chk->sent < SCTP_DATAGRAM_RESEND) {
+ /*
+ * If requested, mark the chunk for
+ * immediate resend, since we sent it being
+ * too big.
+ */
sctp_flight_size_decrease(chk);
sctp_total_flight_decrease(stcb, chk);
chk->sent = SCTP_DATAGRAM_RESEND;
- sctp_ucount_incr(stcb->asoc.sent_queue_retran_cnt);
+ sctp_ucount_incr(asoc->sent_queue_retran_cnt);
chk->rec.data.doing_fast_retransmit = 0;
if (SCTP_BASE_SYSCTL(sctp_logging_level) & SCTP_FLIGHT_LOGGING_ENABLE) {
sctp_misc_ints(SCTP_FLIGHT_LOG_DOWN_PMTU,
@@ -141,7 +157,7 @@ sctp_pathmtu_adjustment(struct sctp_tcb *stcb, uint16_t nxtsz)
(uint32_t)(uintptr_t)chk->whoTo,
chk->rec.data.tsn);
}
- /* Clear any time so NO RTT is being done */
+ /* Clear any time, so NO RTT is being done. */
if (chk->do_rtt == 1) {
chk->do_rtt = 0;
chk->whoTo->rto_needed = 1;
@@ -229,7 +245,7 @@ sctp_notify(struct sctp_inpcb *inp,
}
/* Update the association MTU */
if (stcb->asoc.smallest_mtu > next_mtu) {
- sctp_pathmtu_adjustment(stcb, next_mtu);
+ sctp_pathmtu_adjustment(stcb, next_mtu, true);
}
/* Finally, start the PMTU timer if it was running before. */
if (timer_stopped) {
@@ -5363,7 +5379,7 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
break;
}
if (net->mtu < stcb->asoc.smallest_mtu) {
- sctp_pathmtu_adjustment(stcb, net->mtu);
+ sctp_pathmtu_adjustment(stcb, net->mtu, true);
}
}
}
@@ -5507,7 +5523,7 @@ sctp_setopt(struct socket *so, int optname, void *optval, size_t optsize,
break;
}
if (net->mtu < stcb->asoc.smallest_mtu) {
- sctp_pathmtu_adjustment(stcb, net->mtu);
+ sctp_pathmtu_adjustment(stcb, net->mtu, true);
}
}
}
diff --git a/sys/netinet/sctp_var.h b/sys/netinet/sctp_var.h
index ed01de7d7014..a18dbb5e66e2 100644
--- a/sys/netinet/sctp_var.h
+++ b/sys/netinet/sctp_var.h
@@ -328,7 +328,7 @@ int sctp_ctloutput(struct socket *, struct sockopt *);
void sctp_input_with_port(struct mbuf *, int, uint16_t);
int sctp_input(struct mbuf **, int *, int);
#endif
-void sctp_pathmtu_adjustment(struct sctp_tcb *, uint16_t);
+void sctp_pathmtu_adjustment(struct sctp_tcb *, uint32_t, bool);
void sctp_drain(void);
void sctp_init(void);
void
diff --git a/sys/netinet6/sctp6_usrreq.c b/sys/netinet6/sctp6_usrreq.c
index 516107caf408..361bc4a18a2f 100644
--- a/sys/netinet6/sctp6_usrreq.c
+++ b/sys/netinet6/sctp6_usrreq.c
@@ -233,7 +233,7 @@ sctp6_notify(struct sctp_inpcb *inp,
}
/* Update the association MTU */
if (stcb->asoc.smallest_mtu > next_mtu) {
- sctp_pathmtu_adjustment(stcb, next_mtu);
+ sctp_pathmtu_adjustment(stcb, next_mtu, true);
}
/* Finally, start the PMTU timer if it was running before. */
if (timer_stopped) {