[PATCH net-next 08/10] sctp: add sockopt to get/set stream scheduler parameters

[Marcelo Ricardo Leitner]

As defined per RFC Draft ndata Section 4.3.3, named as
SCTP_STREAM_SCHEDULER_VALUE.

See-also: https://tools.ietf.org/html/draft-ietf-tsvwg-sctp-ndata-13
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leit...@gmail.com>
---
 include/uapi/linux/sctp.h |  7 +++++
 net/sctp/socket.c         | 77 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+)

diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 
0050f10087d224bad87c8c54ad318003381aee12..00ac417d2c4f8468ea2aad32e59806be5c5aa08d
 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -123,6 +123,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_ADD_STREAMS       121
 #define SCTP_SOCKOPT_PEELOFF_FLAGS 122
 #define SCTP_STREAM_SCHEDULER  123
+#define SCTP_STREAM_SCHEDULER_VALUE    124
 
 /* PR-SCTP policies */
 #define SCTP_PR_SCTP_NONE      0x0000
@@ -815,6 +816,12 @@ struct sctp_assoc_value {
     uint32_t                assoc_value;
 };
 
+struct sctp_stream_value {
+       sctp_assoc_t assoc_id;
+       uint16_t stream_id;
+       uint16_t stream_value;
+};
+
 /*
  * 7.2.2 Peer Address Information
  *
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 
ae35dbf2810f78c71ce77115ffe4b0e27a672abc..88c28421ec151e83665efcbcbd8a6403b122205a
 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3945,6 +3945,34 @@ static int sctp_setsockopt_scheduler(struct sock *sk,
        return retval;
 }
 
+static int sctp_setsockopt_scheduler_value(struct sock *sk,
+                                          char __user *optval,
+                                          unsigned int optlen)
+{
+       struct sctp_association *asoc;
+       struct sctp_stream_value params;
+       int retval = -EINVAL;
+
+       if (optlen < sizeof(params))
+               goto out;
+
+       optlen = sizeof(params);
+       if (copy_from_user(&params, optval, optlen)) {
+               retval = -EFAULT;
+               goto out;
+       }
+
+       asoc = sctp_id2assoc(sk, params.assoc_id);
+       if (!asoc)
+               goto out;
+
+       retval = sctp_sched_set_value(asoc, params.stream_id,
+                                     params.stream_value, GFP_KERNEL);
+
+out:
+       return retval;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4129,6 +4157,9 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
        case SCTP_STREAM_SCHEDULER:
                retval = sctp_setsockopt_scheduler(sk, optval, optlen);
                break;
+       case SCTP_STREAM_SCHEDULER_VALUE:
+               retval = sctp_setsockopt_scheduler_value(sk, optval, optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
@@ -6864,6 +6895,48 @@ static int sctp_getsockopt_scheduler(struct sock *sk, 
int len,
        return retval;
 }
 
+static int sctp_getsockopt_scheduler_value(struct sock *sk, int len,
+                                          char __user *optval,
+                                          int __user *optlen)
+{
+       struct sctp_stream_value params;
+       struct sctp_association *asoc;
+       int retval = -EFAULT;
+
+       if (len < sizeof(params)) {
+               retval = -EINVAL;
+               goto out;
+       }
+
+       len = sizeof(params);
+       if (copy_from_user(&params, optval, len))
+               goto out;
+
+       asoc = sctp_id2assoc(sk, params.assoc_id);
+       if (!asoc) {
+               retval = -EINVAL;
+               goto out;
+       }
+
+       retval = sctp_sched_get_value(asoc, params.stream_id,
+                                     &params.stream_value);
+       if (retval)
+               goto out;
+
+       if (put_user(len, optlen)) {
+               retval = -EFAULT;
+               goto out;
+       }
+
+       if (copy_to_user(optval, &params, len)) {
+               retval = -EFAULT;
+               goto out;
+       }
+
+out:
+       return retval;
+}
+
 static int sctp_getsockopt(struct sock *sk, int level, int optname,
                           char __user *optval, int __user *optlen)
 {
@@ -7050,6 +7123,10 @@ static int sctp_getsockopt(struct sock *sk, int level, 
int optname,
                retval = sctp_getsockopt_scheduler(sk, len, optval,
                                                   optlen);
                break;
+       case SCTP_STREAM_SCHEDULER_VALUE:
+               retval = sctp_getsockopt_scheduler_value(sk, len, optval,
+                                                        optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
-- 
2.13.5