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Commit 2cb5c8e3 authored by Neil Horman's avatar Neil Horman Committed by David S. Miller
Browse files

sctp: Add peeloff-flags socket option 



Based on a request raised on the sctp devel list, there is a need to
augment the sctp_peeloff operation while specifying the O_CLOEXEC and
O_NONBLOCK flags (simmilar to the socket syscall).  Since modifying the
SCTP_SOCKOPT_PEELOFF socket option would break user space ABI for existing
programs, this patch creates a new socket option
SCTP_SOCKOPT_PEELOFF_FLAGS, which accepts a third flags parameter to
allow atomic assignment of the socket descriptor flags.

Tested successfully by myself and the requestor

Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Andreas Steinmetz <ast@domdv.de>
CC: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 15324b25

include/uapi/linux/sctp.h

+6 −0
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ typedef __s32 sctp_assoc_t; 
#define SCTP_RESET_STREAMS	119

#define SCTP_RESET_ASSOC	120

#define SCTP_ADD_STREAMS	121

#define SCTP_SOCKOPT_PEELOFF_FLAGS 122



/* PR-SCTP policies */

#define SCTP_PR_SCTP_NONE	0x0000
@@ -978,6 +979,11 @@ typedef struct { 
	int sd;

} sctp_peeloff_arg_t;



typedef struct {

	sctp_peeloff_arg_t p_arg;

	unsigned flags;

} sctp_peeloff_flags_arg_t;



/*

 *  Peer Address Thresholds socket option

 */

net/sctp/socket.c

+72 −15
Original line number Diff line number Diff line
@@ -4933,11 +4933,47 @@ int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp) 
}

EXPORT_SYMBOL(sctp_do_peeloff);



static int sctp_getsockopt_peeloff_common(struct sock *sk, sctp_peeloff_arg_t *peeloff,

					  struct file **newfile, unsigned flags)

{

	struct socket *newsock;

	int retval;



	retval = sctp_do_peeloff(sk, peeloff->associd, &newsock);

	if (retval < 0)

		goto out;



	/* Map the socket to an unused fd that can be returned to the user.  */

	retval = get_unused_fd_flags(flags & SOCK_CLOEXEC);

	if (retval < 0) {

		sock_release(newsock);

		goto out;

	}



	*newfile = sock_alloc_file(newsock, 0, NULL);

	if (IS_ERR(*newfile)) {

		put_unused_fd(retval);

		sock_release(newsock);

		retval = PTR_ERR(*newfile);

		*newfile = NULL;

		return retval;

	}



	pr_debug("%s: sk:%p, newsk:%p, sd:%d\n", __func__, sk, newsock->sk,

		 retval);



	peeloff->sd = retval;



	if (flags & SOCK_NONBLOCK)

		(*newfile)->f_flags |= O_NONBLOCK;

out:

	return retval;

}



static int sctp_getsockopt_peeloff(struct sock *sk, int len, char __user *optval, int __user *optlen)

{

	sctp_peeloff_arg_t peeloff;

	struct socket *newsock;

	struct file *newfile;

	struct file *newfile = NULL;

	int retval = 0;



	if (len < sizeof(sctp_peeloff_arg_t))
@@ -4946,26 +4982,44 @@ static int sctp_getsockopt_peeloff(struct sock *sk, int len, char __user *optval 
	if (copy_from_user(&peeloff, optval, len))

		return -EFAULT;



	retval = sctp_do_peeloff(sk, peeloff.associd, &newsock);

	retval = sctp_getsockopt_peeloff_common(sk, &peeloff, &newfile, 0);

	if (retval < 0)

		goto out;



	/* Map the socket to an unused fd that can be returned to the user.  */

	retval = get_unused_fd_flags(0);

	if (retval < 0) {

		sock_release(newsock);

		goto out;

	/* Return the fd mapped to the new socket.  */

	if (put_user(len, optlen)) {

		fput(newfile);

		put_unused_fd(retval);

		return -EFAULT;

	}



	newfile = sock_alloc_file(newsock, 0, NULL);

	if (IS_ERR(newfile)) {

	if (copy_to_user(optval, &peeloff, len)) {

		fput(newfile);

		put_unused_fd(retval);

		sock_release(newsock);

		return PTR_ERR(newfile);

		return -EFAULT;

	}

	fd_install(retval, newfile);

out:

	return retval;

}



	pr_debug("%s: sk:%p, newsk:%p, sd:%d\n", __func__, sk, newsock->sk,

		 retval);

static int sctp_getsockopt_peeloff_flags(struct sock *sk, int len,

					 char __user *optval, int __user *optlen)

{

	sctp_peeloff_flags_arg_t peeloff;

	struct file *newfile = NULL;

	int retval = 0;



	if (len < sizeof(sctp_peeloff_flags_arg_t))

		return -EINVAL;

	len = sizeof(sctp_peeloff_flags_arg_t);

	if (copy_from_user(&peeloff, optval, len))

		return -EFAULT;



	retval = sctp_getsockopt_peeloff_common(sk, &peeloff.p_arg,

						&newfile, peeloff.flags);

	if (retval < 0)

		goto out;



	/* Return the fd mapped to the new socket.  */

	if (put_user(len, optlen)) {
@@ -4973,7 +5027,7 @@ static int sctp_getsockopt_peeloff(struct sock *sk, int len, char __user *optval 
		put_unused_fd(retval);

		return -EFAULT;

	}

	peeloff.sd = retval;



	if (copy_to_user(optval, &peeloff, len)) {

		fput(newfile);

		put_unused_fd(retval);
@@ -6759,6 +6813,9 @@ static int sctp_getsockopt(struct sock *sk, int level, int optname, 
	case SCTP_SOCKOPT_PEELOFF:

		retval = sctp_getsockopt_peeloff(sk, len, optval, optlen);

		break;

	case SCTP_SOCKOPT_PEELOFF_FLAGS:

		retval = sctp_getsockopt_peeloff_flags(sk, len, optval, optlen);

		break;

	case SCTP_PEER_ADDR_PARAMS:

		retval = sctp_getsockopt_peer_addr_params(sk, len, optval,

							  optlen);