1 files changed, 48 insertions, 0 deletions

diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
index 8fe931a3d7a1..647cb0614f84 100644
--- a/net/dccp/ccid.c
+++ b/net/dccp/ccid.c
@@ -13,6 +13,13 @@
 
 #include "ccid.h"
 
+static u8 builtin_ccids[] = {
+        DCCPC_CCID2,            /* CCID2 is supported by default */
+#if defined(CONFIG_IP_DCCP_CCID3) || defined(CONFIG_IP_DCCP_CCID3_MODULE)
+        DCCPC_CCID3,
+#endif
+};
+
 static struct ccid_operations *ccids[CCID_MAX];
 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
 static atomic_t ccids_lockct = ATOMIC_INIT(0);
@@ -86,6 +93,47 @@ static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
         }
 }
 
+/* check that up to @array_len members in @ccid_array are supported */
+bool ccid_support_check(u8 const *ccid_array, u8 array_len)
+{
+        u8 i, j, found;
+
+        for (i = 0, found = 0; i < array_len; i++, found = 0) {
+                for (j = 0; !found && j < ARRAY_SIZE(builtin_ccids); j++)
+                        found = (ccid_array[i] == builtin_ccids[j]);
+                if (!found)
+                        return false;
+        }
+        return true;
+}
+
+/**
+ * ccid_get_builtin_ccids  -  Provide copy of `builtin' CCID array
+ * @ccid_array: pointer to copy into
+ * @array_len: value to return length into
+ * This function allocates memory - caller must see that it is freed after use.
+ */
+int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len)
+{
+        *ccid_array = kmemdup(builtin_ccids, sizeof(builtin_ccids), gfp_any());
+        if (*ccid_array == NULL)
+                return -ENOBUFS;
+        *array_len = ARRAY_SIZE(builtin_ccids);
+        return 0;
+}
+
+int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
+                                    char __user *optval, int __user *optlen)
+{
+        if (len < sizeof(builtin_ccids))
+                return -EINVAL;
+
+        if (put_user(sizeof(builtin_ccids), optlen) ||
+            copy_to_user(optval, builtin_ccids, sizeof(builtin_ccids)))
+                return -EFAULT;
+        return 0;
+}
+
 int ccid_register(struct ccid_operations *ccid_ops)
 {
         int err = -ENOBUFS;