sctp: get pr_assoc and pr_stream all status with SCTP_PR_SCTP_ALL instead

According to rfc7496 section 4.3 or 4.4:

   sprstat_policy:  This parameter indicates for which PR-SCTP policy
      the user wants the information.  It is an error to use
      SCTP_PR_SCTP_NONE in sprstat_policy.  If SCTP_PR_SCTP_ALL is used,
      the counters provided are aggregated over all supported policies.

We change to dump pr_assoc and pr_stream all status by SCTP_PR_SCTP_ALL
instead, and return error for SCTP_PR_SCTP_NONE, as it also said "It is
an error to use SCTP_PR_SCTP_NONE in sprstat_policy. "

Fixes: 826d253d57b1 ("sctp: add SCTP_PR_ASSOC_STATUS on sctp sockopt")
Fixes: d229d48d183f ("sctp: add SCTP_PR_STREAM_STATUS sockopt for prsctp")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/sctp.h

@@ -301,6 +301,7 @@ enum sctp_sinfo_flags {
 	SCTP_SACK_IMMEDIATELY	= (1 << 3), /* SACK should be sent without delay. */
 	/* 2 bits here have been used by SCTP_PR_SCTP_MASK */
 	SCTP_SENDALL		= (1 << 6),
+	SCTP_PR_SCTP_ALL	= (1 << 7),
 	SCTP_NOTIFICATION	= MSG_NOTIFICATION, /* Next message is not user msg but notification. */
 	SCTP_EOF		= MSG_FIN,  /* Initiate graceful shutdown process. */
 };

net/sctp/socket.c

@@ -7100,14 +7100,14 @@ static int sctp_getsockopt_pr_assocstatus(struct sock *sk, int len,
 	}
 
 	policy = params.sprstat_policy;
-	if (policy & ~SCTP_PR_SCTP_MASK)
+	if (!policy || (policy & ~(SCTP_PR_SCTP_MASK | SCTP_PR_SCTP_ALL)))
 		goto out;
 
 	asoc = sctp_id2assoc(sk, params.sprstat_assoc_id);
 	if (!asoc)
 		goto out;
 
-	if (policy == SCTP_PR_SCTP_NONE) {
+	if (policy & SCTP_PR_SCTP_ALL) {
 		params.sprstat_abandoned_unsent = 0;
 		params.sprstat_abandoned_sent = 0;
 		for (policy = 0; policy <= SCTP_PR_INDEX(MAX); policy++) {
@@ -7159,7 +7159,7 @@ static int sctp_getsockopt_pr_streamstatus(struct sock *sk, int len,
 	}
 
 	policy = params.sprstat_policy;
-	if (policy & ~SCTP_PR_SCTP_MASK)
+	if (!policy || (policy & ~(SCTP_PR_SCTP_MASK | SCTP_PR_SCTP_ALL)))
 		goto out;
 
 	asoc = sctp_id2assoc(sk, params.sprstat_assoc_id);
@@ -7175,7 +7175,7 @@ static int sctp_getsockopt_pr_streamstatus(struct sock *sk, int len,
 		goto out;
 	}
 
-	if (policy == SCTP_PR_SCTP_NONE) {
+	if (policy == SCTP_PR_SCTP_ALL) {
 		params.sprstat_abandoned_unsent = 0;
 		params.sprstat_abandoned_sent = 0;
 		for (policy = 0; policy <= SCTP_PR_INDEX(MAX); policy++) {