Commit d9e2e410 authored by Xin Long's avatar Xin Long Committed by David S. Miller
Browse files

sctp: add the constants/variables and states and some APIs for transport 



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: default avatarXin Long <lucien.xin@gmail.com>
Acked-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3190b649

include/net/sctp/constants.h

+17 −0
Original line number Diff line number Diff line
@@ -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 */

include/net/sctp/sctp.h

+45 −3
Original line number Diff line number Diff line
@@ -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,

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;

include/net/sctp/structs.h

+8 −0
Original line number Diff line number Diff line
@@ -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;