[SCTP] Fix SCTP sendbuffer accouting.

- Include chunk and skb sizes in sendbuffer accounting.
- 2 policies are supported. 0: per socket accouting, 1: per association
  accounting

DaveM: I've made the default per-socket.

Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 54 insertions, 6 deletions

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 358d52b0c445..772998147e3e 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -643,6 +643,7 @@ enum {
         NET_SCTP_MAX_BURST               = 12,
         NET_SCTP_ADDIP_ENABLE            = 13,
         NET_SCTP_PRSCTP_ENABLE           = 14,
+        NET_SCTP_SNDBUF_POLICY           = 15,
 };
 
 /* /proc/sys/net/bridge */
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 7e64cf6bda1e..6c24d9cd3d66 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -154,6 +154,13 @@ extern struct sctp_globals {
         int max_retrans_path;
         int max_retrans_init;
 
+        /*
+         * Policy for preforming sctp/socket accounting
+         * 0   - do socket level accounting, all assocs share sk_sndbuf
+         * 1   - do sctp accounting, each asoc may use sk_sndbuf bytes
+         */
+        int sndbuf_policy;
+
         /* HB.interval              - 30 seconds  */
         int hb_interval;
 
@@ -207,6 +214,7 @@ extern struct sctp_globals {
 #define sctp_valid_cookie_life          (sctp_globals.valid_cookie_life)
 #define sctp_cookie_preserve_enable     (sctp_globals.cookie_preserve_enable)
 #define sctp_max_retrans_association    (sctp_globals.max_retrans_association)
+#define sctp_sndbuf_policy              (sctp_globals.sndbuf_policy)
 #define sctp_max_retrans_path           (sctp_globals.max_retrans_path)
 #define sctp_max_retrans_init           (sctp_globals.max_retrans_init)
 #define sctp_hb_interval                (sctp_globals.hb_interval)
@@ -1212,7 +1220,8 @@ struct sctp_endpoint {
         /* Default timeouts.  */
         int timeouts[SCTP_NUM_TIMEOUT_TYPES];
 
-        /* Various thresholds.  */
+        /* sendbuf acct. policy.        */
+        __u32 sndbuf_policy;
 
         /* Name for debugging output... */
         char *debug_name;
diff --git a/net/sctp/endpointola.c b/net/sctp/endpointola.c
index 544b75077dbd..334f61773e6d 100644
--- a/net/sctp/endpointola.c
+++ b/net/sctp/endpointola.c
@@ -125,6 +125,7 @@ static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
                 sp->autoclose * HZ;
 
         /* Use SCTP specific send buffer space queues.  */
+        ep->sndbuf_policy = sctp_sndbuf_policy;
         sk->sk_write_space = sctp_write_space;
         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 23c85a236c41..2e1f9c3556f5 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1043,6 +1043,9 @@ SCTP_STATIC __init int sctp_init(void)
         sctp_max_retrans_path           = 5;
         sctp_max_retrans_init           = 8;
 
+        /* Sendbuffer growth        - do per-socket accounting */
+        sctp_sndbuf_policy              = 0;
+
         /* HB.interval              - 30 seconds */
         sctp_hb_interval                = 30 * HZ;
 
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 32f2249411fa..0b338eca6dc0 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -115,9 +115,17 @@ static inline int sctp_wspace(struct sctp_association *asoc)
         struct sock *sk = asoc->base.sk;
         int amt = 0;
 
-        amt = sk->sk_sndbuf - asoc->sndbuf_used;
+        if (asoc->ep->sndbuf_policy) {
+                /* make sure that no association uses more than sk_sndbuf */
+                amt = sk->sk_sndbuf - asoc->sndbuf_used;
+        } else {
+                /* do socket level accounting */
+                amt = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
+        }
+
         if (amt < 0)
                 amt = 0;
+
         return amt;
 }
 
@@ -138,12 +146,21 @@ static inline void sctp_set_owner_w(struct sctp_chunk *chunk)
         /* The sndbuf space is tracked per association.  */
         sctp_association_hold(asoc);
 
+        skb_set_owner_w(chunk->skb, sk);
+
         chunk->skb->destructor = sctp_wfree;
         /* Save the chunk pointer in skb for sctp_wfree to use later.  */
         *((struct sctp_chunk **)(chunk->skb->cb)) = chunk;
 
-        asoc->sndbuf_used += SCTP_DATA_SNDSIZE(chunk);
-        sk->sk_wmem_queued += SCTP_DATA_SNDSIZE(chunk);
+        asoc->sndbuf_used += SCTP_DATA_SNDSIZE(chunk) +
+                                sizeof(struct sk_buff) +
+                                sizeof(struct sctp_chunk);
+
+        sk->sk_wmem_queued += SCTP_DATA_SNDSIZE(chunk) +
+                                sizeof(struct sk_buff) +
+                                sizeof(struct sctp_chunk);
+
+        atomic_add(sizeof(struct sctp_chunk), &sk->sk_wmem_alloc);
 }
 
 /* Verify that this is a valid address. */
@@ -4422,8 +4439,17 @@ static void sctp_wfree(struct sk_buff *skb)
         chunk = *((struct sctp_chunk **)(skb->cb));
         asoc = chunk->asoc;
         sk = asoc->base.sk;
-        asoc->sndbuf_used -= SCTP_DATA_SNDSIZE(chunk);
-        sk->sk_wmem_queued -= SCTP_DATA_SNDSIZE(chunk);
+        asoc->sndbuf_used -= SCTP_DATA_SNDSIZE(chunk) +
+                                sizeof(struct sk_buff) +
+                                sizeof(struct sctp_chunk);
+
+        sk->sk_wmem_queued -= SCTP_DATA_SNDSIZE(chunk) +
+                                sizeof(struct sk_buff) +
+                                sizeof(struct sctp_chunk);
+
+        atomic_sub(sizeof(struct sctp_chunk), &sk->sk_wmem_alloc);
+
+        sock_wfree(skb);
         __sctp_write_space(asoc);
 
         sctp_association_put(asoc);
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 89fa20c73a5c..7fc31849312b 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -110,6 +110,14 @@ static ctl_table sctp_table[] = {
                 .proc_handler   = &proc_dointvec
         },
         {
+                .ctl_name       = NET_SCTP_SNDBUF_POLICY,
+                .procname       = "sndbuf_policy",
+                .data           = &sctp_sndbuf_policy,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec
+        },
+        {
                 .ctl_name       = NET_SCTP_PATH_MAX_RETRANS,
                 .procname       = "path_max_retrans",
                 .data           = &sctp_max_retrans_path,