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Commit e89c2095 authored by Wei Yongjun's avatar Wei Yongjun Committed by David S. Miller
Browse files

sctp: Bring SCTP_MAXSEG socket option into ietf API extension compliance 



Brings maxseg socket option set/get into line with the latest ietf socket
extensions API draft, while maintaining backwards compatibility.

Signed-off-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 161c8d2f

net/sctp/socket.c

+107 −23
Original line number Diff line number Diff line
@@ -2778,33 +2778,78 @@ static int sctp_setsockopt_mappedv4(struct sock *sk, char __user *optval, int op 
}



/*

 * 7.1.17 Set the maximum fragrmentation size (SCTP_MAXSEG)

 *

 * This socket option specifies the maximum size to put in any outgoing

 * SCTP chunk.  If a message is larger than this size it will be

 * 8.1.16.  Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG)

 * This option will get or set the maximum size to put in any outgoing

 * SCTP DATA chunk.  If a message is larger than this size it will be

 * fragmented by SCTP into the specified size.  Note that the underlying

 * SCTP implementation may fragment into smaller sized chunks when the

 * PMTU of the underlying association is smaller than the value set by

 * the user.

 * the user.  The default value for this option is '0' which indicates

 * the user is NOT limiting fragmentation and only the PMTU will effect

 * SCTP's choice of DATA chunk size.  Note also that values set larger

 * than the maximum size of an IP datagram will effectively let SCTP

 * control fragmentation (i.e. the same as setting this option to 0).

 *

 * The following structure is used to access and modify this parameter:

 *

 * struct sctp_assoc_value {

 *   sctp_assoc_t assoc_id;

 *   uint32_t assoc_value;

 * };

 *

 * assoc_id:  This parameter is ignored for one-to-one style sockets.

 *    For one-to-many style sockets this parameter indicates which

 *    association the user is performing an action upon.  Note that if

 *    this field's value is zero then the endpoints default value is

 *    changed (effecting future associations only).

 * assoc_value:  This parameter specifies the maximum size in bytes.

 */

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

{

	struct sctp_assoc_value params;

	struct sctp_association *asoc;

	struct sctp_sock *sp = sctp_sk(sk);

	int val;



	if (optlen < sizeof(int))

		return -EINVAL;

	if (get_user(val, (int __user *)optval))

	if (optlen == sizeof(int)) {

		printk(KERN_WARNING

		   "SCTP: Use of int in maxseg socket option deprecated\n");

		printk(KERN_WARNING

		   "SCTP: Use struct sctp_assoc_value instead\n");

		if (copy_from_user(&val, optval, optlen))

			return -EFAULT;

		params.assoc_id = 0;

	} else if (optlen == sizeof(struct sctp_assoc_value)) {

		if (copy_from_user(&params, optval, optlen))

			return -EFAULT;

		val = params.assoc_value;

	} else

		return -EINVAL;



	if ((val != 0) && ((val < 8) || (val > SCTP_MAX_CHUNK_LEN)))

		return -EINVAL;



	asoc = sctp_id2assoc(sk, params.assoc_id);

	if (!asoc && params.assoc_id && sctp_style(sk, UDP))

		return -EINVAL;



	if (asoc) {

		if (val == 0) {

			val = asoc->pathmtu;

			val -= sp->pf->af->net_header_len;

			val -= sizeof(struct sctphdr) +

					sizeof(struct sctp_data_chunk);

		}



		asoc->frag_point = val;

	} else {

		sp->user_frag = val;



		/* Update the frag_point of the existing associations. */

		list_for_each_entry(asoc, &(sp->ep->asocs), asocs) {

			asoc->frag_point = sctp_frag_point(sp, asoc->pathmtu);

		}

	}



	return 0;

}
@@ -5100,30 +5145,69 @@ static int sctp_getsockopt_context(struct sock *sk, int len, 
}



/*

 * 7.1.17 Set the maximum fragrmentation size (SCTP_MAXSEG)

 *

 * This socket option specifies the maximum size to put in any outgoing

 * SCTP chunk.  If a message is larger than this size it will be

 * 8.1.16.  Get or Set the Maximum Fragmentation Size (SCTP_MAXSEG)

 * This option will get or set the maximum size to put in any outgoing

 * SCTP DATA chunk.  If a message is larger than this size it will be

 * fragmented by SCTP into the specified size.  Note that the underlying

 * SCTP implementation may fragment into smaller sized chunks when the

 * PMTU of the underlying association is smaller than the value set by

 * the user.

 * the user.  The default value for this option is '0' which indicates

 * the user is NOT limiting fragmentation and only the PMTU will effect

 * SCTP's choice of DATA chunk size.  Note also that values set larger

 * than the maximum size of an IP datagram will effectively let SCTP

 * control fragmentation (i.e. the same as setting this option to 0).

 *

 * The following structure is used to access and modify this parameter:

 *

 * struct sctp_assoc_value {

 *   sctp_assoc_t assoc_id;

 *   uint32_t assoc_value;

 * };

 *

 * assoc_id:  This parameter is ignored for one-to-one style sockets.

 *    For one-to-many style sockets this parameter indicates which

 *    association the user is performing an action upon.  Note that if

 *    this field's value is zero then the endpoints default value is

 *    changed (effecting future associations only).

 * assoc_value:  This parameter specifies the maximum size in bytes.

 */

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

				  char __user *optval, int __user *optlen)

{

	int val;

	struct sctp_assoc_value params;

	struct sctp_association *asoc;



	if (len < sizeof(int))

	if (len == sizeof(int)) {

		printk(KERN_WARNING

		   "SCTP: Use of int in maxseg socket option deprecated\n");

		printk(KERN_WARNING

		   "SCTP: Use struct sctp_assoc_value instead\n");

		params.assoc_id = 0;

	} else if (len >= sizeof(struct sctp_assoc_value)) {

		len = sizeof(struct sctp_assoc_value);

		if (copy_from_user(&params, optval, sizeof(params)))

			return -EFAULT;

	} else

		return -EINVAL;



	len = sizeof(int);

	asoc = sctp_id2assoc(sk, params.assoc_id);

	if (!asoc && params.assoc_id && sctp_style(sk, UDP))

		return -EINVAL;



	if (asoc)

		params.assoc_value = asoc->frag_point;

	else

		params.assoc_value = sctp_sk(sk)->user_frag;



	val = sctp_sk(sk)->user_frag;

	if (put_user(len, optlen))

		return -EFAULT;

	if (copy_to_user(optval, &val, len))

	if (len == sizeof(int)) {

		if (copy_to_user(optval, &params.assoc_value, len))

			return -EFAULT;

	} else {

		if (copy_to_user(optval, &params, len))

			return -EFAULT;

	}



	return 0;

}