[SCTP]: Implement SCTP_MAX_BURST socket option.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 67 insertions, 3 deletions

diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
index 5ddb85599863..bb37724495a5 100644
--- a/include/net/sctp/constants.h
+++ b/include/net/sctp/constants.h
@@ -283,7 +283,7 @@ enum { SCTP_MAX_GABS = 16 };
 #define SCTP_RTO_BETA           2   /* 1/4 when converted to right shifts. */
 
 /* Maximum number of new data packets that can be sent in a burst.  */
-#define SCTP_MAX_BURST          4
+#define SCTP_DEFAULT_MAX_BURST          4
 
 #define SCTP_CLOCK_GRANULARITY  1       /* 1 jiffy */
 
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 37b4a24e589b..7b4fff93ba7f 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -276,6 +276,7 @@ struct sctp_sock {
         __u32 default_context;
         __u32 default_timetolive;
         __u32 default_rcv_context;
+        int max_burst;
 
         /* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
          * the destination address every heartbeat interval. This value
diff --git a/include/net/sctp/user.h b/include/net/sctp/user.h
index 1b3153c2cdf0..6d2b57758cca 100644
--- a/include/net/sctp/user.h
+++ b/include/net/sctp/user.h
@@ -101,6 +101,8 @@ enum sctp_optname {
 #define SCTP_FRAGMENT_INTERLEAVE SCTP_FRAGMENT_INTERLEAVE
         SCTP_PARTIAL_DELIVERY_POINT,    /* Set/Get partial delivery point */
 #define SCTP_PARTIAL_DELIVERY_POINT SCTP_PARTIAL_DELIVERY_POINT
+        SCTP_MAX_BURST,         /* Set/Get max burst */
+#define SCTP_MAX_BURST SCTP_MAX_BURST
 
         /* Internal Socket Options. Some of the sctp library functions are 
          * implemented using these socket options.
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 85af1cb70fe8..37a343e1ebb7 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -143,7 +143,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
         /* Initialize the maximum mumber of new data packets that can be sent
          * in a burst.
          */
-        asoc->max_burst = sctp_max_burst;
+        asoc->max_burst = sp->max_burst;
 
         /* initialize association timers */
         asoc->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 7c28c9b959e2..c361deb6cea9 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1042,7 +1042,7 @@ SCTP_STATIC __init int sctp_init(void)
         sctp_cookie_preserve_enable     = 1;
 
         /* Max.Burst                - 4 */
-        sctp_max_burst                  = SCTP_MAX_BURST;
+        sctp_max_burst                  = SCTP_DEFAULT_MAX_BURST;
 
         /* Association.Max.Retrans  - 10 attempts
          * Path.Max.Retrans         - 5  attempts (per destination address)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index dda2f6700f5b..f904f2bc0f2c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2892,6 +2892,36 @@ static int sctp_setsockopt_partial_delivery_point(struct sock *sk,
         return 0; /* is this the right error code? */
 }
 
+/*
+ * 7.1.28.  Set or Get the maximum burst (SCTP_MAX_BURST)
+ *
+ * This option will allow a user to change the maximum burst of packets
+ * that can be emitted by this association.  Note that the default value
+ * is 4, and some implementations may restrict this setting so that it
+ * can only be lowered.
+ *
+ * NOTE: This text doesn't seem right.  Do this on a socket basis with
+ * future associations inheriting the socket value.
+ */
+static int sctp_setsockopt_maxburst(struct sock *sk,
+                                    char __user *optval,
+                                    int optlen)
+{
+        int val;
+
+        if (optlen != sizeof(int))
+                return -EINVAL;
+        if (get_user(val, (int __user *)optval))
+                return -EFAULT;
+
+        if (val < 0)
+                return -EINVAL;
+
+        sctp_sk(sk)->max_burst = val;
+
+        return 0;
+}
+
 /* API 6.2 setsockopt(), getsockopt()
  *
  * Applications use setsockopt() and getsockopt() to set or retrieve
@@ -3012,6 +3042,9 @@ SCTP_STATIC int sctp_setsockopt(struct sock *sk, int level, int optname,
         case SCTP_FRAGMENT_INTERLEAVE:
                 retval = sctp_setsockopt_fragment_interleave(sk, optval, optlen);
                 break;
+        case SCTP_MAX_BURST:
+                retval = sctp_setsockopt_maxburst(sk, optval, optlen);
+                break;
         default:
                 retval = -ENOPROTOOPT;
                 break;
@@ -3171,6 +3204,7 @@ SCTP_STATIC int sctp_init_sock(struct sock *sk)
         sp->default_timetolive = 0;
 
         sp->default_rcv_context = 0;
+        sp->max_burst = sctp_max_burst;
 
         /* Initialize default setup parameters. These parameters
          * can be modified with the SCTP_INITMSG socket option or
@@ -4689,6 +4723,30 @@ static int sctp_getsockopt_partial_delivery_point(struct sock *sk, int len,
         return -ENOTSUPP;
 }
 
+/*
+ * 7.1.28.  Set or Get the maximum burst (SCTP_MAX_BURST)
+ * (chapter and verse is quoted at sctp_setsockopt_maxburst())
+ */
+static int sctp_getsockopt_maxburst(struct sock *sk, int len,
+                                    char __user *optval,
+                                    int __user *optlen)
+{
+        int val;
+
+        if (len < sizeof(int))
+                return -EINVAL;
+
+        len = sizeof(int);
+
+        val = sctp_sk(sk)->max_burst;
+        if (put_user(len, optlen))
+                return -EFAULT;
+        if (copy_to_user(optval, &val, len))
+                return -EFAULT;
+
+        return -ENOTSUPP;
+}
+
 SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
                                 char __user *optval, int __user *optlen)
 {
@@ -4809,6 +4867,9 @@ SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
                 retval = sctp_getsockopt_partial_delivery_point(sk, len, optval,
                                                                 optlen);
                 break;
+        case SCTP_MAX_BURST:
+                retval = sctp_getsockopt_maxburst(sk, len, optval, optlen);
+                break;
         default:
                 retval = -ENOPROTOOPT;
                 break;