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Commit 29450559 authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

dccp: Feature negotiation for minimum-checksum-coverage 



This provides feature negotiation for server minimum checksum coverage
which so far has been missing.

Since sender/receiver coverage values range only from 0...15, their
type has also been reduced in size from u16 to u4.

Feature-negotiation options are now generated for both sender and receiver
coverage, i.e. when the peer has `forgotten' to enable partial coverage
then feature negotiation will automatically enable (negotiate) the partial
coverage value for this connection.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 49aebc66

include/linux/dccp.h

+2 −2
Original line number Diff line number Diff line
@@ -527,8 +527,8 @@ struct dccp_sock { 
	__u32				dccps_timestamp_time;

	__u16				dccps_l_ack_ratio;

	__u16				dccps_r_ack_ratio;

	__u16				dccps_pcslen;

	__u16				dccps_pcrlen;

	__u8				dccps_pcslen:4;

	__u8				dccps_pcrlen:4;

	__u64				dccps_ndp_count:48;

	unsigned long			dccps_rate_last;

	struct dccp_minisock		dccps_minisock;

net/dccp/proto.c

+40 −13
Original line number Diff line number Diff line
@@ -470,6 +470,42 @@ static int dccp_setsockopt_service(struct sock *sk, const __be32 service, 
	return 0;

}



static int dccp_setsockopt_cscov(struct sock *sk, int cscov, bool rx)

{

	u8 *list, len;

	int i, rc;



	if (cscov < 0 || cscov > 15)

		return -EINVAL;

	/*

	 * Populate a list of permissible values, in the range cscov...15. This

	 * is necessary since feature negotiation of single values only works if

	 * both sides incidentally choose the same value. Since the list starts

	 * lowest-value first, negotiation will pick the smallest shared value.

	 */

	if (cscov == 0)

		return 0;

	len = 16 - cscov;



	list = kmalloc(len, GFP_KERNEL);

	if (list == NULL)

		return -ENOBUFS;



	for (i = 0; i < len; i++)

		list[i] = cscov++;



	rc = dccp_feat_register_sp(sk, DCCPF_MIN_CSUM_COVER, rx, list, len);



	if (rc == 0) {

		if (rx)

			dccp_sk(sk)->dccps_pcrlen = cscov;

		else

			dccp_sk(sk)->dccps_pcslen = cscov;

	}

	kfree(list);

	return rc;

}



static int do_dccp_setsockopt(struct sock *sk, int level, int optname,

		char __user *optval, int optlen)

{
@@ -502,20 +538,11 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname, 
		else

			dp->dccps_server_timewait = (val != 0);

		break;

	case DCCP_SOCKOPT_SEND_CSCOV:	/* sender side, RFC 4340, sec. 9.2 */

		if (val < 0 || val > 15)

			err = -EINVAL;

		else

			dp->dccps_pcslen = val;

	case DCCP_SOCKOPT_SEND_CSCOV:

		err = dccp_setsockopt_cscov(sk, val, false);

		break;

	case DCCP_SOCKOPT_RECV_CSCOV:	/* receiver side, RFC 4340 sec. 9.2.1 */

		if (val < 0 || val > 15)

			err = -EINVAL;

		else {

			dp->dccps_pcrlen = val;

			/* FIXME: add feature negotiation,

			 * ChangeL(MinimumChecksumCoverage, val) */

		}

	case DCCP_SOCKOPT_RECV_CSCOV:

		err = dccp_setsockopt_cscov(sk, val, true);

		break;

	default:

		err = -ENOPROTOOPT;