dccp: Deprecate old setsockopt framework

The previous setsockopt interface, which passed socket options via struct
dccp_so_feat, is complicated/difficult to use. Continuing to support it leads to
ugly code since the old approach did not distinguish between NN and SP values.

This patch removes the old setsockopt interface and replaces it with two new
functions to register NN/SP values for feature negotiation. 
These are essentially wrappers around the internal __feat_register functions,
with checking added to avoid

 * wrong usage (type);
 * changing values while the connection is in progress.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 51 deletions

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 1117d4d..3090fc4 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -470,44 +470,6 @@ static int dccp_setsockopt_service(struct sock *sk, const __be32 service,
 	return 0;
 }
 
-/* byte 1 is feature.  the rest is the preference list */
-static int dccp_setsockopt_change(struct sock *sk, int type,
-				  struct dccp_so_feat __user *optval)
-{
-	struct dccp_so_feat opt;
-	u8 *val;
-	int rc;
-
-	if (copy_from_user(&opt, optval, sizeof(opt)))
-		return -EFAULT;
-	/*
-	 * rfc4340: 6.1. Change Options
-	 */
-	if (opt.dccpsf_len < 1)
-		return -EINVAL;
-
-	val = kmalloc(opt.dccpsf_len, GFP_KERNEL);
-	if (!val)
-		return -ENOMEM;
-
-	if (copy_from_user(val, opt.dccpsf_val, opt.dccpsf_len)) {
-		rc = -EFAULT;
-		goto out_free_val;
-	}
-
-	rc = dccp_feat_change(dccp_msk(sk), type, opt.dccpsf_feat,
-			      val, opt.dccpsf_len, GFP_KERNEL);
-	if (rc)
-		goto out_free_val;
-
-out:
-	return rc;
-
-out_free_val:
-	kfree(val);
-	goto out;
-}
-
 static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
 		char __user *optval, int optlen)
 {
@@ -530,20 +492,9 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
 		err = 0;
 		break;
 	case DCCP_SOCKOPT_CHANGE_L:
-		if (optlen != sizeof(struct dccp_so_feat))
-			err = -EINVAL;
-		else
-			err = dccp_setsockopt_change(sk, DCCPO_CHANGE_L,
-						     (struct dccp_so_feat __user *)
-						     optval);
-		break;
 	case DCCP_SOCKOPT_CHANGE_R:
-		if (optlen != sizeof(struct dccp_so_feat))
-			err = -EINVAL;
-		else
-			err = dccp_setsockopt_change(sk, DCCPO_CHANGE_R,
-						     (struct dccp_so_feat __user *)
-						     optval);
+		DCCP_WARN("sockopt(CHANGE_L/R) is deprecated: fix your app\n");
+		err = 0;
 		break;
 	case DCCP_SOCKOPT_SERVER_TIMEWAIT:
 		if (dp->dccps_role != DCCP_ROLE_SERVER)