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, 27 insertions, 45 deletions

diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 4f86a48723f6..47ce9abaf72b 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -364,53 +364,35 @@ static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
         return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
 }
 
-int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
-                     u8 *val, u8 len, gfp_t gfp)
-{
-        struct dccp_opt_pend *opt;
-
-        dccp_feat_debug(type, feature, *val);
-
-        if (len > 3) {
-                DCCP_WARN("invalid length %d\n", len);
+/**
+ * dccp_feat_register_sp  -  Register requests to change SP feature values
+ * @sk: client or listening socket
+ * @feat: one of %dccp_feature_numbers
+ * @is_local: whether the local (1) or remote (0) @feat is meant
+ * @list: array of preferred values, in descending order of preference
+ * @len: length of @list in bytes
+ */
+int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
+                          u8 const *list, u8 len)
+{        /* any changes must be registered before establishing the connection */
+        if (sk->sk_state != DCCP_CLOSED)
+                return -EISCONN;
+        if (dccp_feat_type(feat) != FEAT_SP)
                 return -EINVAL;
-        }
-        /* XXX add further sanity checks */
-
-        /* check if that feature is already being negotiated */
-        list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
-                /* ok we found a negotiation for this option already */
-                if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
-                        dccp_pr_debug("Replacing old\n");
-                        /* replace */
-                        BUG_ON(opt->dccpop_val == NULL);
-                        kfree(opt->dccpop_val);
-                        opt->dccpop_val  = val;
-                        opt->dccpop_len  = len;
-                        opt->dccpop_conf = 0;
-                        return 0;
-                }
-        }
-
-        /* negotiation for a new feature */
-        opt = kmalloc(sizeof(*opt), gfp);
-        if (opt == NULL)
-                return -ENOMEM;
-
-        opt->dccpop_type = type;
-        opt->dccpop_feat = feature;
-        opt->dccpop_len  = len;
-        opt->dccpop_val  = val;
-        opt->dccpop_conf = 0;
-        opt->dccpop_sc   = NULL;
-
-        BUG_ON(opt->dccpop_val == NULL);
-
-        list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
-        return 0;
+        return __feat_register_sp(&dccp_sk(sk)->dccps_featneg, feat, is_local,
+                                  0, list, len);
 }
 
-EXPORT_SYMBOL_GPL(dccp_feat_change);
+/* Analogous to dccp_feat_register_sp(), but for non-negotiable values */
+int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val)
+{
+        /* any changes must be registered before establishing the connection */
+        if (sk->sk_state != DCCP_CLOSED)
+                return -EISCONN;
+        if (dccp_feat_type(feat) != FEAT_NN)
+                return -EINVAL;
+        return __feat_register_nn(&dccp_sk(sk)->dccps_featneg, feat, 0, val);
+}
 
 /*
  *      Tracking features whose value depend on the choice of CCID
@@ -1108,7 +1090,7 @@ int dccp_feat_init(struct sock *sk)
 
         /* Ack ratio */
         rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
-                                dmsk->dccpms_ack_ratio);
+                                dp->dccps_l_ack_ratio);
 out:
         return rc;
 }