From: Diego Elio 'Flameeyes' Pettenà <flameeyes@xxxxxxxxx>
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.
Signed-off-by: Diego Elio Pettenà <flameeyes@xxxxxxxxx>
---
net/sctp/socket.c | 35 ++++++++++++++++++++++++++++++++++-
1 files changed, 34 insertions(+), 1 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index ca44917..8872028 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3595,7 +3595,40 @@ 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);
+
+ /*
+ * SEQPACKET-style sockets in LISTENING state are valid, for
+ * SCTP, so only discard TCP-style sockets in LISTENING state.
+ */
+ if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
+ goto out;
+
+ switch (cmd) {
+ case SIOCINQ: {
+ struct sk_buff *skb;
+ unsigned int 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
--
1.7.3.1
--
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