[PATCH net-next 07/10] sctp: add sockopt to get/set stream scheduler

[Marcelo Ricardo Leitner]

As defined per RFC Draft ndata Section 4.3.2, named as
SCTP_STREAM_SCHEDULER.

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 |  1 +
 net/sctp/socket.c         | 75 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)

diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 
4487e7625ddbd48be1868a8292a807ecd0a314bc..0050f10087d224bad87c8c54ad318003381aee12
 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -122,6 +122,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_RESET_ASSOC       120
 #define SCTP_ADD_STREAMS       121
 #define SCTP_SOCKOPT_PEELOFF_FLAGS 122
+#define SCTP_STREAM_SCHEDULER  123
 
 /* PR-SCTP policies */
 #define SCTP_PR_SCTP_NONE      0x0000
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 
d207734326b085e60625e4333f74221481114892..ae35dbf2810f78c71ce77115ffe4b0e27a672abc
 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -79,6 +79,7 @@
 #include <net/sock.h>
 #include <net/sctp/sctp.h>
 #include <net/sctp/sm.h>
+#include <net/sctp/stream_sched.h>
 
 /* Forward declarations for internal helper functions. */
 static int sctp_writeable(struct sock *sk);
@@ -3914,6 +3915,36 @@ static int sctp_setsockopt_add_streams(struct sock *sk,
        return retval;
 }
 
+static int sctp_setsockopt_scheduler(struct sock *sk,
+                                    char __user *optval,
+                                    unsigned int optlen)
+{
+       struct sctp_association *asoc;
+       struct sctp_assoc_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;
+       }
+
+       if (params.assoc_value > SCTP_SS_MAX)
+               goto out;
+
+       asoc = sctp_id2assoc(sk, params.assoc_id);
+       if (!asoc)
+               goto out;
+
+       retval = sctp_sched_set_sched(asoc, params.assoc_value);
+
+out:
+       return retval;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4095,6 +4126,9 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
        case SCTP_ADD_STREAMS:
                retval = sctp_setsockopt_add_streams(sk, optval, optlen);
                break;
+       case SCTP_STREAM_SCHEDULER:
+               retval = sctp_setsockopt_scheduler(sk, optval, optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
@@ -6793,6 +6827,43 @@ static int sctp_getsockopt_enable_strreset(struct sock 
*sk, int len,
        return retval;
 }
 
+static int sctp_getsockopt_scheduler(struct sock *sk, int len,
+                                    char __user *optval,
+                                    int __user *optlen)
+{
+       struct sctp_assoc_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;
+       }
+
+       params.assoc_value = sctp_sched_get_sched(asoc);
+
+       if (put_user(len, optlen))
+               goto out;
+
+       if (copy_to_user(optval, &params, 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)
 {
@@ -6975,6 +7046,10 @@ static int sctp_getsockopt(struct sock *sk, int level, 
int optname,
                retval = sctp_getsockopt_enable_strreset(sk, len, optval,
                                                         optlen);
                break;
+       case SCTP_STREAM_SCHEDULER:
+               retval = sctp_getsockopt_scheduler(sk, len, optval,
+                                                  optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
-- 
2.13.5