Merge branch 'sctp-rfc7496-support'

Xin Long says:

====================
sctp: implement rfc7496 in sctp

This patchset implements "Additional Policies for the Partially Reliable
Stream Control Transmission Protocol Extension" described on RFC7496.

The Partially Reliable SCTP (PR-SCTP) extension defined in [RFC3758]
provides a generic method for senders to abandon user messages. The
decision to abandon a user message is sender side only, and the exact
condition is called a "PR-SCTP policy". This patchset implements 3
policies:

 1. Timed Reliability:  This allows the sender to specify a timeout for
    a user message after which the SCTP stack abandons the user message.

 2. Limited Retransmission Policy:  Allows limitation of the number of
    retransmissions.

 3. Priority Policy:  Allows removal of lower-priority messages if space
    for higher-priority messages is needed in the send buffer.

Patch 1-3 add some sockopts in sctp to set/get pr_sctp policy status.
Patch 4-6 implement these 3 policies one by one.
====================

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 63 insertions, 2 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 83c5ec58b93a..8626bdd3249a 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -602,6 +602,16 @@ struct sctp_chunk {
 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
 	struct sctp_sndrcvinfo sinfo;
 
+	/* We use this field to record param for prsctp policies,
+	 * for TTL policy, it is the time_to_drop of this chunk,
+	 * for RTX policy, it is the max_sent_count of this chunk,
+	 * for PRIO policy, it is the priority of this chunk.
+	 */
+	unsigned long prsctp_param;
+
+	/* How many times this chunk have been sent, for prsctp RTX policy */
+	int sent_count;
+
 	/* Which association does this belong to?  */
 	struct sctp_association *asoc;
 
@@ -1074,6 +1084,8 @@ void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
 		     sctp_retransmit_reason_t);
 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
 int sctp_outq_uncork(struct sctp_outq *, gfp_t gfp);
+void sctp_prsctp_prune(struct sctp_association *asoc,
+		       struct sctp_sndrcvinfo *sinfo, int msg_len);
 /* Uncork and flush an outqueue.  */
 static inline void sctp_outq_cork(struct sctp_outq *q)
 {
@@ -1256,7 +1268,8 @@ struct sctp_endpoint {
 	/* SCTP-AUTH: endpoint shared keys */
 	struct list_head endpoint_shared_keys;
 	__u16 active_key_id;
-	__u8  auth_enable;
+	__u8  auth_enable:1,
+	      prsctp_enable:1;
 };
 
 /* Recover the outter endpoint structure. */
@@ -1848,9 +1861,15 @@ struct sctp_association {
 	__u16 active_key_id;
 
 	__u8 need_ecne:1,	/* Need to send an ECNE Chunk? */
-	     temp:1;		/* Is it a temporary association? */
+	     temp:1,		/* Is it a temporary association? */
+	     prsctp_enable:1;
 
 	struct sctp_priv_assoc_stats stats;
+
+	int sent_cnt_removable;
+
+	__u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1];
+	__u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1];
 };
 
 
diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index ce70fe6b45df..d304f4c9792c 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -112,6 +112,31 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_SOCKOPT_CONNECTX	110		/* CONNECTX requests. */
 #define SCTP_SOCKOPT_CONNECTX3	111	/* CONNECTX requests (updated) */
 #define SCTP_GET_ASSOC_STATS	112	/* Read only */
+#define SCTP_PR_SUPPORTED	113
+#define SCTP_DEFAULT_PRINFO	114
+#define SCTP_PR_ASSOC_STATUS	115
+
+/* PR-SCTP policies */
+#define SCTP_PR_SCTP_NONE	0x0000
+#define SCTP_PR_SCTP_TTL	0x0010
+#define SCTP_PR_SCTP_RTX	0x0020
+#define SCTP_PR_SCTP_PRIO	0x0030
+#define SCTP_PR_SCTP_MAX	SCTP_PR_SCTP_PRIO
+#define SCTP_PR_SCTP_MASK	0x0030
+
+#define __SCTP_PR_INDEX(x)	((x >> 4) - 1)
+#define SCTP_PR_INDEX(x)	__SCTP_PR_INDEX(SCTP_PR_SCTP_ ## x)
+
+#define SCTP_PR_POLICY(x)	((x) & SCTP_PR_SCTP_MASK)
+#define SCTP_PR_SET_POLICY(flags, x)	\
+	do {				\
+		flags &= ~SCTP_PR_SCTP_MASK;	\
+		flags |= x;		\
+	} while (0)
+
+#define SCTP_PR_TTL_ENABLED(x)	(SCTP_PR_POLICY(x) == SCTP_PR_SCTP_TTL)
+#define SCTP_PR_RTX_ENABLED(x)	(SCTP_PR_POLICY(x) == SCTP_PR_SCTP_RTX)
+#define SCTP_PR_PRIO_ENABLED(x)	(SCTP_PR_POLICY(x) == SCTP_PR_SCTP_PRIO)
 
 /* These are bit fields for msghdr->msg_flags.  See section 5.1.  */
 /* On user space Linux, these live in <bits/socket.h> as an enum.  */
@@ -902,4 +927,21 @@ struct sctp_paddrthlds {
 	__u16 spt_pathpfthld;
 };
 
+/*
+ * Socket Option for Getting the Association/Stream-Specific PR-SCTP Status
+ */
+struct sctp_prstatus {
+	sctp_assoc_t sprstat_assoc_id;
+	__u16 sprstat_sid;
+	__u16 sprstat_policy;
+	__u64 sprstat_abandoned_unsent;
+	__u64 sprstat_abandoned_sent;
+};
+
+struct sctp_default_prinfo {
+	sctp_assoc_t pr_assoc_id;
+	__u32 pr_value;
+	__u16 pr_policy;
+};
+
 #endif /* _UAPI_SCTP_H */