These are 4 constants described in rfc8899#section-5.1.2:
MAX_PROBES, MIN_PLPMTU, MAX_PLPMTU, BASE_PLPMTU;
And 2 variables described in rfc8899#section-5.1.3:
PROBED_SIZE, PROBE_COUNT;
And 5 states described in rfc8899#section-5.2:
DISABLED, BASE, SEARCH, SEARCH_COMPLETE, ERROR;
And these 4 APIs are used to reset/update PLPMTUD, check if PLPMTUD is
enabled, and calculate the additional headers length for a transport.
Note the member 'probe_high' in transport will be set to the probe
size when a probe fails with this probe size in the next patches.
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
---
include/net/sctp/constants.h | 17 +++++++++++++
include/net/sctp/sctp.h | 48 +++++++++++++++++++++++++++++++++---
include/net/sctp/structs.h | 8 ++++++
3 files changed, 70 insertions(+), 3 deletions(-)
diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index 449cf9cb428b..85f6a105c59d 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -200,6 +200,23 @@ enum sctp_sock_state {
SCTP_SS_CLOSING = TCP_CLOSE_WAIT,
};
+enum sctp_plpmtud_state {
+ SCTP_PL_DISABLED,
+ SCTP_PL_BASE,
+ SCTP_PL_SEARCH,
+ SCTP_PL_COMPLETE,
+ SCTP_PL_ERROR,
+};
+
+#define SCTP_BASE_PLPMTU 1200
+#define SCTP_MAX_PLPMTU 9000
+#define SCTP_MIN_PLPMTU 512
+
+#define SCTP_MAX_PROBES 3
+
+#define SCTP_PL_BIG_STEP 32
+#define SCTP_PL_MIN_STEP 4
+
/* These functions map various type to printable names. */
const char *sctp_cname(const union sctp_subtype id); /* chunk types */
const char *sctp_oname(const union sctp_subtype id); /* other events */
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
index 86f74f2fe6de..08347d3f004f 100644
--- a/include/net/sctp/sctp.h
+++ b/include/net/sctp/sctp.h
@@ -573,14 +573,15 @@ static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *
/* Calculate max payload size given a MTU, or the total overhead if
* given MTU is zero
*/
-static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
- __u32 mtu, __u32 extra)
+static inline __u32 __sctp_mtu_payload(const struct sctp_sock *sp,
+ const struct sctp_transport *t,
+ __u32 mtu, __u32 extra)
{
__u32 overhead = sizeof(struct sctphdr) + extra;
if (sp) {
overhead += sp->pf->af->net_header_len;
- if (sp->udp_port)
+ if (sp->udp_port && (!t || t->encap_port))
overhead += sizeof(struct udphdr);
} else {
overhead += sizeof(struct ipv6hdr);
@@ -592,6 +593,12 @@ static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
return mtu ? mtu - overhead : overhead;
}
+static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp,
+ __u32 mtu, __u32 extra)
+{
+ return __sctp_mtu_payload(sp, NULL, mtu, extra);
+}
+
static inline __u32 sctp_dst_mtu(const struct dst_entry *dst)
{
return SCTP_TRUNC4(max_t(__u32, dst_mtu(dst),
@@ -615,6 +622,41 @@ static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize)
return sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, datasize);
}
+static inline int sctp_transport_pl_hlen(struct sctp_transport *t)
+{
+ return __sctp_mtu_payload(sctp_sk(t->asoc->base.sk), t, 0, 0);
+}
+
+static inline void sctp_transport_pl_reset(struct sctp_transport *t)
+{
+ if (t->probe_interval && (t->param_flags & SPP_PMTUD_ENABLE) &&
+ (t->state == SCTP_ACTIVE || t->state == SCTP_UNKNOWN)) {
+ if (t->pl.state == SCTP_PL_DISABLED) {
+ t->pl.state = SCTP_PL_BASE;
+ t->pl.pmtu = SCTP_BASE_PLPMTU;
+ t->pl.probe_size = SCTP_BASE_PLPMTU;
+ }
+ } else {
+ if (t->pl.state != SCTP_PL_DISABLED)
+ t->pl.state = SCTP_PL_DISABLED;
+ }
+}
+
+static inline void sctp_transport_pl_update(struct sctp_transport *t)
+{
+ if (t->pl.state == SCTP_PL_DISABLED)
+ return;
+
+ t->pl.state = SCTP_PL_BASE;
+ t->pl.pmtu = SCTP_BASE_PLPMTU;
+ t->pl.probe_size = SCTP_BASE_PLPMTU;
+}
+
+static inline bool sctp_transport_pl_enabled(struct sctp_transport *t)
+{
+ return t->pl.state != SCTP_PL_DISABLED;
+}
+
static inline bool sctp_newsk_ready(const struct sock *sk)
{
return sock_flag(sk, SOCK_DEAD) || sk->sk_socket;
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index bf5d22deaefb..85d3566c2227 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -978,6 +978,14 @@ struct sctp_transport {
char cacc_saw_newack;
} cacc;
+ struct {
+ __u16 pmtu;
+ __u16 probe_size;
+ __u16 probe_high;
+ __u8 probe_count;
+ __u8 state;
+ } pl; /* plpmtud related */
+
/* 64-bit random number sent with heartbeat. */
__u64 hb_nonce;
--
2.27.0
