sctp: Bring SCTP_DELAYED_ACK socket option into API compliance

Brings delayed_ack socket option set/get into line with the latest ietf
socket extensions API draft, while maintaining backwards compatibility.

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

3 files changed, 169 insertions, 93 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index b4cd2b71953f..7b79d1e781a8 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -136,6 +136,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
 
         /* Set association default SACK delay */
         asoc->sackdelay = msecs_to_jiffies(sp->sackdelay);
+        asoc->sackfreq = sp->sackfreq;
 
         /* Set the association default flags controlling
          * Heartbeat, SACK delay, and Path MTU Discovery.
@@ -261,6 +262,7 @@ static struct sctp_association *sctp_association_init(struct sctp_association *a
          * already received one packet.]
          */
         asoc->peer.sack_needed = 1;
+        asoc->peer.sack_cnt = 0;
 
         /* Assume that the peer will tell us if he recognizes ASCONF
          * as part of INIT exchange.
@@ -615,6 +617,7 @@ struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc,
          * association configured value.
          */
         peer->sackdelay = asoc->sackdelay;
+        peer->sackfreq = asoc->sackfreq;
 
         /* Enable/disable heartbeat, SACK delay, and path MTU discovery
          * based on association setting.
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 23a9f1a95b7d..b083312c725a 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -190,20 +190,28 @@ static int sctp_gen_sack(struct sctp_association *asoc, int force,
          * unacknowledged DATA chunk. ...
          */
         if (!asoc->peer.sack_needed) {
-                /* We will need a SACK for the next packet.  */
-                asoc->peer.sack_needed = 1;
+                asoc->peer.sack_cnt++;
 
                 /* Set the SACK delay timeout based on the
                  * SACK delay for the last transport
                  * data was received from, or the default
                  * for the association.
                  */
-                if (trans)
+                if (trans) {
+                        /* We will need a SACK for the next packet.  */
+                        if (asoc->peer.sack_cnt >= trans->sackfreq - 1)
+                                asoc->peer.sack_needed = 1;
+
                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
                                 trans->sackdelay;
-                else
+                } else {
+                        /* We will need a SACK for the next packet.  */
+                        if (asoc->peer.sack_cnt >= asoc->sackfreq - 1)
+                                asoc->peer.sack_needed = 1;
+
                         asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
                                 asoc->sackdelay;
+                }
 
                 /* Restart the SACK timer. */
                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
@@ -216,6 +224,7 @@ static int sctp_gen_sack(struct sctp_association *asoc, int force,
                         goto nomem;
 
                 asoc->peer.sack_needed = 0;
+                asoc->peer.sack_cnt = 0;
 
                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack));
 
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index e7e3baf7009e..66985871401b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2305,74 +2305,98 @@ static int sctp_setsockopt_peer_addr_params(struct sock *sk,
         return 0;
 }
 
-/* 7.1.23. Delayed Ack Timer (SCTP_DELAYED_ACK_TIME)
- *
- *   This options will get or set the delayed ack timer.  The time is set
- *   in milliseconds.  If the assoc_id is 0, then this sets or gets the
- *   endpoints default delayed ack timer value.  If the assoc_id field is
- *   non-zero, then the set or get effects the specified association.
- *
- *   struct sctp_assoc_value {
- *       sctp_assoc_t            assoc_id;
- *       uint32_t                assoc_value;
- *   };
- *
- *     assoc_id    - This parameter, indicates which association the
- *                   user is preforming an action upon. Note that if
- *                   this field's value is zero then the endpoints
- *                   default value is changed (effecting future
- *                   associations only).
- *
- *     assoc_value - This parameter contains the number of milliseconds
- *                   that the user is requesting the delayed ACK timer
- *                   be set to. Note that this value is defined in
- *                   the standard to be between 200 and 500 milliseconds.
- *
- *                   Note: a value of zero will leave the value alone,
- *                   but disable SACK delay. A non-zero value will also
- *                   enable SACK delay.
+/*
+ * 7.1.23.  Get or set delayed ack timer (SCTP_DELAYED_SACK)
+ *
+ * This option will effect the way delayed acks are performed.  This
+ * option allows you to get or set the delayed ack time, in
+ * milliseconds.  It also allows changing the delayed ack frequency.
+ * Changing the frequency to 1 disables the delayed sack algorithm.  If
+ * the assoc_id is 0, then this sets or gets the endpoints default
+ * values.  If the assoc_id field is non-zero, then the set or get
+ * effects the specified association for the one to many model (the
+ * assoc_id field is ignored by the one to one model).  Note that if
+ * sack_delay or sack_freq are 0 when setting this option, then the
+ * current values will remain unchanged.
+ *
+ * struct sctp_sack_info {
+ *     sctp_assoc_t            sack_assoc_id;
+ *     uint32_t                sack_delay;
+ *     uint32_t                sack_freq;
+ * };
+ *
+ * sack_assoc_id -  This parameter, indicates which association the user
+ *    is performing an action upon.  Note that if this field's value is
+ *    zero then the endpoints default value is changed (effecting future
+ *    associations only).
+ *
+ * sack_delay -  This parameter contains the number of milliseconds that
+ *    the user is requesting the delayed ACK timer be set to.  Note that
+ *    this value is defined in the standard to be between 200 and 500
+ *    milliseconds.
+ *
+ * sack_freq -  This parameter contains the number of packets that must
+ *    be received before a sack is sent without waiting for the delay
+ *    timer to expire.  The default value for this is 2, setting this
+ *    value to 1 will disable the delayed sack algorithm.
  */
 
-static int sctp_setsockopt_delayed_ack_time(struct sock *sk,
+static int sctp_setsockopt_delayed_ack(struct sock *sk,
                                             char __user *optval, int optlen)
 {
-        struct sctp_assoc_value  params;
+        struct sctp_sack_info    params;
         struct sctp_transport   *trans = NULL;
         struct sctp_association *asoc = NULL;
         struct sctp_sock        *sp = sctp_sk(sk);
 
-        if (optlen != sizeof(struct sctp_assoc_value))
-                return - EINVAL;
+        if (optlen == sizeof(struct sctp_sack_info)) {
+                if (copy_from_user(&params, optval, optlen))
+                        return -EFAULT;
 
-        if (copy_from_user(&params, optval, optlen))
-                return -EFAULT;
+                if (params.sack_delay == 0 && params.sack_freq == 0)
+                        return 0;
+        } else if (optlen == sizeof(struct sctp_assoc_value)) {
+                printk(KERN_WARNING "SCTP: Use of struct sctp_sack_info "
+                       "in delayed_ack socket option deprecated\n");
+                printk(KERN_WARNING "SCTP: struct sctp_sack_info instead\n");
+                if (copy_from_user(&params, optval, optlen))
+                        return -EFAULT;
+
+                if (params.sack_delay == 0)
+                        params.sack_freq = 1;
+                else
+                        params.sack_freq = 0;
+        } else
+                return - EINVAL;
 
         /* Validate value parameter. */
-        if (params.assoc_value > 500)
+        if (params.sack_delay > 500)
                 return -EINVAL;
 
-        /* Get association, if assoc_id != 0 and the socket is a one
+        /* Get association, if sack_assoc_id != 0 and the socket is a one
          * to many style socket, and an association was not found, then
          * the id was invalid.
          */
-        asoc = sctp_id2assoc(sk, params.assoc_id);
-        if (!asoc && params.assoc_id && sctp_style(sk, UDP))
+        asoc = sctp_id2assoc(sk, params.sack_assoc_id);
+        if (!asoc && params.sack_assoc_id && sctp_style(sk, UDP))
                 return -EINVAL;
 
-        if (params.assoc_value) {
+        if (params.sack_delay) {
                 if (asoc) {
                         asoc->sackdelay =
-                                msecs_to_jiffies(params.assoc_value);
+                                msecs_to_jiffies(params.sack_delay);
                         asoc->param_flags =
                                 (asoc->param_flags & ~SPP_SACKDELAY) |
                                 SPP_SACKDELAY_ENABLE;
                 } else {
-                        sp->sackdelay = params.assoc_value;
+                        sp->sackdelay = params.sack_delay;
                         sp->param_flags =
                                 (sp->param_flags & ~SPP_SACKDELAY) |
                                 SPP_SACKDELAY_ENABLE;
                 }
-        } else {
+        }
+
+        if (params.sack_freq == 1) {
                 if (asoc) {
                         asoc->param_flags =
                                 (asoc->param_flags & ~SPP_SACKDELAY) |
@@ -2382,22 +2406,40 @@ static int sctp_setsockopt_delayed_ack_time(struct sock *sk,
                                 (sp->param_flags & ~SPP_SACKDELAY) |
                                 SPP_SACKDELAY_DISABLE;
                 }
+        } else if (params.sack_freq > 1) {
+                if (asoc) {
+                        asoc->sackfreq = params.sack_freq;
+                        asoc->param_flags =
+                                (asoc->param_flags & ~SPP_SACKDELAY) |
+                                SPP_SACKDELAY_ENABLE;
+                } else {
+                        sp->sackfreq = params.sack_freq;
+                        sp->param_flags =
+                                (sp->param_flags & ~SPP_SACKDELAY) |
+                                SPP_SACKDELAY_ENABLE;
+                }
         }
 
         /* If change is for association, also apply to each transport. */
         if (asoc) {
                 list_for_each_entry(trans, &asoc->peer.transport_addr_list,
                                 transports) {
-                        if (params.assoc_value) {
+                        if (params.sack_delay) {
                                 trans->sackdelay =
-                                        msecs_to_jiffies(params.assoc_value);
+                                        msecs_to_jiffies(params.sack_delay);
                                 trans->param_flags =
                                         (trans->param_flags & ~SPP_SACKDELAY) |
                                         SPP_SACKDELAY_ENABLE;
-                        } else {
+                        }
+                        if (params.sack_delay == 1) {
                                 trans->param_flags =
                                         (trans->param_flags & ~SPP_SACKDELAY) |
                                         SPP_SACKDELAY_DISABLE;
+                        } else if (params.sack_freq > 1) {
+                                trans->sackfreq = params.sack_freq;
+                                trans->param_flags =
+                                        (trans->param_flags & ~SPP_SACKDELAY) |
+                                        SPP_SACKDELAY_ENABLE;
                         }
                 }
         }
@@ -3186,8 +3228,8 @@ SCTP_STATIC int sctp_setsockopt(struct sock *sk, int level, int optname,
                 retval = sctp_setsockopt_peer_addr_params(sk, optval, optlen);
                 break;
 
-        case SCTP_DELAYED_ACK_TIME:
-                retval = sctp_setsockopt_delayed_ack_time(sk, optval, optlen);
+        case SCTP_DELAYED_ACK:
+                retval = sctp_setsockopt_delayed_ack(sk, optval, optlen);
                 break;
         case SCTP_PARTIAL_DELIVERY_POINT:
                 retval = sctp_setsockopt_partial_delivery_point(sk, optval, optlen);
@@ -3446,6 +3488,7 @@ SCTP_STATIC int sctp_init_sock(struct sock *sk)
         sp->pathmaxrxt  = sctp_max_retrans_path;
         sp->pathmtu     = 0; // allow default discovery
         sp->sackdelay   = sctp_sack_timeout;
+        sp->sackfreq    = 3;
         sp->param_flags = SPP_HB_ENABLE |
                           SPP_PMTUD_ENABLE |
                           SPP_SACKDELAY_ENABLE;
@@ -3999,70 +4042,91 @@ static int sctp_getsockopt_peer_addr_params(struct sock *sk, int len,
         return 0;
 }
 
-/* 7.1.23. Delayed Ack Timer (SCTP_DELAYED_ACK_TIME)
- *
- *   This options will get or set the delayed ack timer.  The time is set
- *   in milliseconds.  If the assoc_id is 0, then this sets or gets the
- *   endpoints default delayed ack timer value.  If the assoc_id field is
- *   non-zero, then the set or get effects the specified association.
- *
- *   struct sctp_assoc_value {
- *       sctp_assoc_t            assoc_id;
- *       uint32_t                assoc_value;
- *   };
+/*
+ * 7.1.23.  Get or set delayed ack timer (SCTP_DELAYED_SACK)
+ *
+ * This option will effect the way delayed acks are performed.  This
+ * option allows you to get or set the delayed ack time, in
+ * milliseconds.  It also allows changing the delayed ack frequency.
+ * Changing the frequency to 1 disables the delayed sack algorithm.  If
+ * the assoc_id is 0, then this sets or gets the endpoints default
+ * values.  If the assoc_id field is non-zero, then the set or get
+ * effects the specified association for the one to many model (the
+ * assoc_id field is ignored by the one to one model).  Note that if
+ * sack_delay or sack_freq are 0 when setting this option, then the
+ * current values will remain unchanged.
+ *
+ * struct sctp_sack_info {
+ *     sctp_assoc_t            sack_assoc_id;
+ *     uint32_t                sack_delay;
+ *     uint32_t                sack_freq;
+ * };
  *
- *     assoc_id    - This parameter, indicates which association the
- *                   user is preforming an action upon. Note that if
- *                   this field's value is zero then the endpoints
- *                   default value is changed (effecting future
- *                   associations only).
+ * sack_assoc_id -  This parameter, indicates which association the user
+ *    is performing an action upon.  Note that if this field's value is
+ *    zero then the endpoints default value is changed (effecting future
+ *    associations only).
  *
- *     assoc_value - This parameter contains the number of milliseconds
- *                   that the user is requesting the delayed ACK timer
- *                   be set to. Note that this value is defined in
- *                   the standard to be between 200 and 500 milliseconds.
+ * sack_delay -  This parameter contains the number of milliseconds that
+ *    the user is requesting the delayed ACK timer be set to.  Note that
+ *    this value is defined in the standard to be between 200 and 500
+ *    milliseconds.
  *
- *                   Note: a value of zero will leave the value alone,
- *                   but disable SACK delay. A non-zero value will also
- *                   enable SACK delay.
+ * sack_freq -  This parameter contains the number of packets that must
+ *    be received before a sack is sent without waiting for the delay
+ *    timer to expire.  The default value for this is 2, setting this
+ *    value to 1 will disable the delayed sack algorithm.
  */
-static int sctp_getsockopt_delayed_ack_time(struct sock *sk, int len,
+static int sctp_getsockopt_delayed_ack(struct sock *sk, int len,
                                             char __user *optval,
                                             int __user *optlen)
 {
-        struct sctp_assoc_value  params;
+        struct sctp_sack_info    params;
         struct sctp_association *asoc = NULL;
         struct sctp_sock        *sp = sctp_sk(sk);
 
-        if (len < sizeof(struct sctp_assoc_value))
-                return - EINVAL;
+        if (len >= sizeof(struct sctp_sack_info)) {
+                len = sizeof(struct sctp_sack_info);
 
-        len = sizeof(struct sctp_assoc_value);
-
-        if (copy_from_user(&params, optval, len))
-                return -EFAULT;
+                if (copy_from_user(&params, optval, len))
+                        return -EFAULT;
+        } else if (len == sizeof(struct sctp_assoc_value)) {
+                printk(KERN_WARNING "SCTP: Use of struct sctp_sack_info "
+                       "in delayed_ack socket option deprecated\n");
+                printk(KERN_WARNING "SCTP: struct sctp_sack_info instead\n");
+                if (copy_from_user(&params, optval, len))
+                        return -EFAULT;
+        } else
+                return - EINVAL;
 
-        /* Get association, if assoc_id != 0 and the socket is a one
+        /* Get association, if sack_assoc_id != 0 and the socket is a one
          * to many style socket, and an association was not found, then
          * the id was invalid.
          */
-        asoc = sctp_id2assoc(sk, params.assoc_id);
-        if (!asoc && params.assoc_id && sctp_style(sk, UDP))
+        asoc = sctp_id2assoc(sk, params.sack_assoc_id);
+        if (!asoc && params.sack_assoc_id && sctp_style(sk, UDP))
                 return -EINVAL;
 
         if (asoc) {
                 /* Fetch association values. */
-                if (asoc->param_flags & SPP_SACKDELAY_ENABLE)
-                        params.assoc_value = jiffies_to_msecs(
+                if (asoc->param_flags & SPP_SACKDELAY_ENABLE) {
+                        params.sack_delay = jiffies_to_msecs(
                                 asoc->sackdelay);
-                else
-                        params.assoc_value = 0;
+                        params.sack_freq = asoc->sackfreq;
+
+                } else {
+                        params.sack_delay = 0;
+                        params.sack_freq = 1;
+                }
         } else {
                 /* Fetch socket values. */
-                if (sp->param_flags & SPP_SACKDELAY_ENABLE)
-                        params.assoc_value  = sp->sackdelay;
-                else
-                        params.assoc_value  = 0;
+                if (sp->param_flags & SPP_SACKDELAY_ENABLE) {
+                        params.sack_delay  = sp->sackdelay;
+                        params.sack_freq = sp->sackfreq;
+                } else {
+                        params.sack_delay  = 0;
+                        params.sack_freq = 1;
+                }
         }
 
         if (copy_to_user(optval, &params, len))
@@ -5218,8 +5282,8 @@ SCTP_STATIC int sctp_getsockopt(struct sock *sk, int level, int optname,
                 retval = sctp_getsockopt_peer_addr_params(sk, len, optval,
                                                           optlen);
                 break;
-        case SCTP_DELAYED_ACK_TIME:
-                retval = sctp_getsockopt_delayed_ack_time(sk, len, optval,
+        case SCTP_DELAYED_ACK:
+                retval = sctp_getsockopt_delayed_ack(sk, len, optval,
                                                           optlen);
                 break;
         case SCTP_INITMSG: