[PATCH] sctp: implement SIOCINQ ioctl()

From: Diego Elio 'Flameeyes' PettenÃ
Date: Wed Jun 23 2010 - 17:41:22 EST


This simple patch copies the current approach for SIOCINQ ioctl() from DCCP
into SCTp so that the userland code working with SCTP can use a similar
interface across different protocols to know how much space to allocate for
a buffer.
---
net/sctp/socket.c | 31 ++++++++++++++++++++++++++++++-
1 files changed, 30 insertions(+), 1 deletions(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 44a1ab0..3135b4e 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3595,7 +3595,36 @@ out:
/* The SCTP ioctl handler. */
SCTP_STATIC int sctp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
- return -ENOIOCTLCMD;
+ int rc = -ENOTCONN;
+
+ sctp_lock_sock(sk);
+
+ if (sctp_sstate(sk, LISTENING))
+ goto out;
+
+ switch(cmd) {
+ case SIOCINQ: {
+ struct sk_buff *skb;
+ unsigned long amount = 0;
+
+ skb = skb_peek(&sk->sk_receive_queue);
+ if (skb != NULL) {
+ /*
+ * We will only return the amount of this packet since
+ * that is all that will be read.
+ */
+ amount = skb->len;
+ }
+ rc = put_user(amount, (int __user *)arg);
+ }
+ break;
+ default:
+ rc = -ENOIOCTLCMD;
+ break;
+ }
+out:
+ sctp_release_sock(sk);
+ return rc;
}

/* This is the function which gets called during socket creation to
--
1.7.1

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