From 65040c33ee8d0199ab7686402bffdbf9e1e26cbe Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Diego=20Elio=20=27Flameeyes=27=20Petten=C3=B2?= Date: Fri, 3 Sep 2010 03:47:03 +0000 Subject: [PATCH] sctp: implement SIOCINQ ioctl() (take 3) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Pettenò Signed-off-by: David S. Miller --- net/sctp/socket.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index cf6dcc908b88..6a691d84aef4 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -3592,7 +3592,40 @@ 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