sctp: add SCTP_DEFAULT_PRINFO into sctp sockopt

This patch adds SCTP_DEFAULT_PRINFO to sctp sockopt. It is used
to set/get sctp Partially Reliable Policies' default params,
which includes 3 policies (ttl, rtx, prio) and their values.

Still, if we set policy params in sndinfo, we will use the params
of sndinfo against chunks, instead of the default params.

In this patch, we will use 5-8bit of sp/asoc->default_flags
to store prsctp policies, and reuse asoc->default_timetolive
to store their values. It means if we enable and set prsctp
policy, prior ttl timeout in sctp will not work any more.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 91 insertions, 0 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 7460ddebd9ce..c03fe1b76706 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3694,6 +3694,47 @@ out:
 	return retval;
 }
 
+static int sctp_setsockopt_default_prinfo(struct sock *sk,
+					  char __user *optval,
+					  unsigned int optlen)
+{
+	struct sctp_default_prinfo info;
+	struct sctp_association *asoc;
+	int retval = -EINVAL;
+
+	if (optlen != sizeof(info))
+		goto out;
+
+	if (copy_from_user(&info, optval, sizeof(info))) {
+		retval = -EFAULT;
+		goto out;
+	}
+
+	if (info.pr_policy & ~SCTP_PR_SCTP_MASK)
+		goto out;
+
+	if (info.pr_policy == SCTP_PR_SCTP_NONE)
+		info.pr_value = 0;
+
+	asoc = sctp_id2assoc(sk, info.pr_assoc_id);
+	if (asoc) {
+		SCTP_PR_SET_POLICY(asoc->default_flags, info.pr_policy);
+		asoc->default_timetolive = info.pr_value;
+	} else if (!info.pr_assoc_id) {
+		struct sctp_sock *sp = sctp_sk(sk);
+
+		SCTP_PR_SET_POLICY(sp->default_flags, info.pr_policy);
+		sp->default_timetolive = info.pr_value;
+	} else {
+		goto out;
+	}
+
+	retval = 0;
+
+out:
+	return retval;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -3857,6 +3898,9 @@ static int sctp_setsockopt(struct sock *sk, int level, int optname,
 	case SCTP_PR_SUPPORTED:
 		retval = sctp_setsockopt_pr_supported(sk, optval, optlen);
 		break;
+	case SCTP_DEFAULT_PRINFO:
+		retval = sctp_setsockopt_default_prinfo(sk, optval, optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;
@@ -6243,6 +6287,49 @@ out:
 	return retval;
 }
 
+static int sctp_getsockopt_default_prinfo(struct sock *sk, int len,
+					  char __user *optval,
+					  int __user *optlen)
+{
+	struct sctp_default_prinfo info;
+	struct sctp_association *asoc;
+	int retval = -EFAULT;
+
+	if (len < sizeof(info)) {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	len = sizeof(info);
+	if (copy_from_user(&info, optval, len))
+		goto out;
+
+	asoc = sctp_id2assoc(sk, info.pr_assoc_id);
+	if (asoc) {
+		info.pr_policy = SCTP_PR_POLICY(asoc->default_flags);
+		info.pr_value = asoc->default_timetolive;
+	} else if (!info.pr_assoc_id) {
+		struct sctp_sock *sp = sctp_sk(sk);
+
+		info.pr_policy = SCTP_PR_POLICY(sp->default_flags);
+		info.pr_value = sp->default_timetolive;
+	} else {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	if (put_user(len, optlen))
+		goto out;
+
+	if (copy_to_user(optval, &info, len))
+		goto out;
+
+	retval = 0;
+
+out:
+	return retval;
+}
+
 static int sctp_getsockopt(struct sock *sk, int level, int optname,
 			   char __user *optval, int __user *optlen)
 {
@@ -6399,6 +6486,10 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname,
 	case SCTP_PR_SUPPORTED:
 		retval = sctp_getsockopt_pr_supported(sk, len, optval, optlen);
 		break;
+	case SCTP_DEFAULT_PRINFO:
+		retval = sctp_getsockopt_default_prinfo(sk, len, optval,
+							optlen);
+		break;
 	default:
 		retval = -ENOPROTOOPT;
 		break;