dccp: Per-socket initialisation of feature negotiation

This provides feature-negotiation initialisation for both DCCP sockets
and DCCP request_sockets, to support feature negotiation during
connection setup.

It also resolves a FIXME regarding the congestion control
initialisation.

Thanks to Wei Yongjun for help with the IPv6 side of this patch.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 55 insertions, 0 deletions

diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 9a37b6ce3ac..069d8ffe4c6 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -90,6 +90,20 @@ static u8 dccp_feat_type(u8 feat_num)
         return dccp_feat_table[idx].reconciliation;
 }
 
+/* copy constructor, fval must not already contain allocated memory */
+static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
+{
+        fval->sp.len = len;
+        if (fval->sp.len > 0) {
+                fval->sp.vec = kmemdup(val, len, gfp_any());
+                if (fval->sp.vec == NULL) {
+                        fval->sp.len = 0;
+                        return -ENOBUFS;
+                }
+        }
+        return 0;
+}
+
 static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
 {
         if (unlikely(val == NULL))
@@ -99,6 +113,28 @@ static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
         memset(val, 0, sizeof(*val));
 }
 
+static struct dccp_feat_entry *
+              dccp_feat_clone_entry(struct dccp_feat_entry const *original)
+{
+        struct dccp_feat_entry *new;
+        u8 type = dccp_feat_type(original->feat_num);
+
+        if (type == FEAT_UNKNOWN)
+                return NULL;
+
+        new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any());
+        if (new == NULL)
+                return NULL;
+
+        if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val,
+                                                      original->val.sp.vec,
+                                                      original->val.sp.len)) {
+                kfree(new);
+                return NULL;
+        }
+        return new;
+}
+
 static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
 {
         if (entry != NULL) {
@@ -133,6 +169,25 @@ void dccp_feat_list_purge(struct list_head *fn_list)
 }
 EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
 
+/* generate @to as full clone of @from - @to must not contain any nodes */
+int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
+{
+        struct dccp_feat_entry *entry, *new;
+
+        INIT_LIST_HEAD(to);
+        list_for_each_entry(entry, from, node) {
+                new = dccp_feat_clone_entry(entry);
+                if (new == NULL)
+                        goto cloning_failed;
+                list_add_tail(&new->node, to);
+        }
+        return 0;
+
+cloning_failed:
+        dccp_feat_list_purge(to);
+        return -ENOMEM;
+}
+
 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
                      u8 *val, u8 len, gfp_t gfp)
 {