[PATCHv3 net-next 4/4] sctp: add sockopt SCTP_EVENT

[Xin Long]

This patch adds sockopt SCTP_EVENT described in rfc6525#section-6.2.
With this sockopt users can subscribe to an event from a specified
asoc.

Signed-off-by: Xin Long <lucien....@gmail.com>
---
 include/uapi/linux/sctp.h |  7 ++++
 net/sctp/socket.c         | 88 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
index 66afa5b..d584073 100644
--- a/include/uapi/linux/sctp.h
+++ b/include/uapi/linux/sctp.h
@@ -129,6 +129,7 @@ typedef __s32 sctp_assoc_t;
 #define SCTP_STREAM_SCHEDULER_VALUE    124
 #define SCTP_INTERLEAVING_SUPPORTED    125
 #define SCTP_SENDMSG_CONNECT   126
+#define SCTP_EVENT     127
 
 /* PR-SCTP policies */
 #define SCTP_PR_SCTP_NONE      0x0000
@@ -1154,6 +1155,12 @@ struct sctp_add_streams {
        uint16_t sas_outstrms;
 };
 
+struct sctp_event {
+       sctp_assoc_t se_assoc_id;
+       uint16_t se_type;
+       uint8_t se_on;
+};
+
 /* SCTP Stream schedulers */
 enum sctp_sched_type {
        SCTP_SS_FCFS,
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index c771827..e16c090 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4288,6 +4288,57 @@ static int sctp_setsockopt_reuse_port(struct sock *sk, 
char __user *optval,
        return 0;
 }
 
+static int sctp_setsockopt_event(struct sock *sk, char __user *optval,
+                                unsigned int optlen)
+{
+       struct sctp_association *asoc;
+       struct sctp_ulpevent *event;
+       struct sctp_event param;
+       int retval = 0;
+
+       if (optlen < sizeof(param)) {
+               retval = -EINVAL;
+               goto out;
+       }
+
+       optlen = sizeof(param);
+       if (copy_from_user(&param, optval, optlen)) {
+               retval = -EFAULT;
+               goto out;
+       }
+
+       if (param.se_type < SCTP_SN_TYPE_BASE ||
+           param.se_type > SCTP_SN_TYPE_MAX) {
+               retval = -EINVAL;
+               goto out;
+       }
+
+       asoc = sctp_id2assoc(sk, param.se_assoc_id);
+       if (!asoc) {
+               sctp_ulpevent_type_set(&sctp_sk(sk)->subscribe,
+                                      param.se_type, param.se_on);
+               goto out;
+       }
+
+       sctp_ulpevent_type_set(&asoc->subscribe, param.se_type, param.se_on);
+
+       if (param.se_type == SCTP_SENDER_DRY_EVENT && param.se_on) {
+               if (sctp_outq_is_empty(&asoc->outqueue)) {
+                       event = sctp_ulpevent_make_sender_dry_event(asoc,
+                                       GFP_USER | __GFP_NOWARN);
+                       if (!event) {
+                               retval = -ENOMEM;
+                               goto out;
+                       }
+
+                       asoc->stream.si->enqueue_event(&asoc->ulpq, event);
+               }
+       }
+
+out:
+       return retval;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -4485,6 +4536,9 @@ static int sctp_setsockopt(struct sock *sk, int level, 
int optname,
        case SCTP_REUSE_PORT:
                retval = sctp_setsockopt_reuse_port(sk, optval, optlen);
                break;
+       case SCTP_EVENT:
+               retval = sctp_setsockopt_event(sk, optval, optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
@@ -7430,6 +7484,37 @@ static int sctp_getsockopt_reuse_port(struct sock *sk, 
int len,
        return 0;
 }
 
+static int sctp_getsockopt_event(struct sock *sk, int len, char __user *optval,
+                                int __user *optlen)
+{
+       struct sctp_association *asoc;
+       struct sctp_event param;
+       __u16 subscribe;
+
+       if (len < sizeof(param))
+               return -EINVAL;
+
+       len = sizeof(param);
+       if (copy_from_user(&param, optval, len))
+               return -EFAULT;
+
+       if (param.se_type < SCTP_SN_TYPE_BASE ||
+           param.se_type > SCTP_SN_TYPE_MAX)
+               return -EINVAL;
+
+       asoc = sctp_id2assoc(sk, param.se_assoc_id);
+       subscribe = asoc ? asoc->subscribe : sctp_sk(sk)->subscribe;
+       param.se_on = sctp_ulpevent_type_enabled(subscribe, param.se_type);
+
+       if (put_user(len, optlen))
+               return -EFAULT;
+
+       if (copy_to_user(optval, &param, len))
+               return -EFAULT;
+
+       return 0;
+}
+
 static int sctp_getsockopt(struct sock *sk, int level, int optname,
                           char __user *optval, int __user *optlen)
 {
@@ -7628,6 +7713,9 @@ static int sctp_getsockopt(struct sock *sk, int level, 
int optname,
        case SCTP_REUSE_PORT:
                retval = sctp_getsockopt_reuse_port(sk, len, optval, optlen);
                break;
+       case SCTP_EVENT:
+               retval = sctp_getsockopt_event(sk, len, optval, optlen);
+               break;
        default:
                retval = -ENOPROTOOPT;
                break;
-- 
2.1.0