1 files changed, 42 insertions, 1 deletions

diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 99d7b7f9efa9..ed0851fa3cb3 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 
 #include "dccp.h"
+#include "ccid.h"
 #include "feat.h"
 
 #define DCCP_FEAT_SP_NOAGREE (-123)
@@ -26,6 +27,8 @@ int dccp_feat_change(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len,
 
         dccp_pr_debug("feat change type=%d feat=%d\n", type, feature);
 
+        /* XXX sanity check feat change request */
+
         /* check if that feature is already being negotiated */
         list_for_each_entry(opt, &dp->dccps_options.dccpo_pending,
                             dccpop_node) {
@@ -62,11 +65,49 @@ int dccp_feat_change(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len,
 
 EXPORT_SYMBOL_GPL(dccp_feat_change);
 
+static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
+{
+        struct dccp_sock *dp = dccp_sk(sk);
+        /* figure out if we are changing our CCID or the peer's */
+        const int rx = type == DCCPO_CHANGE_R;
+        const u8 ccid_nr = rx ? dp->dccps_options.dccpo_rx_ccid :
+                                dp->dccps_options.dccpo_tx_ccid;
+        struct ccid *new_ccid;
+
+        /* Check if nothing is being changed. */
+        if (ccid_nr == new_ccid_nr)
+                return 0;
+
+        new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
+        if (new_ccid == NULL)
+                return -ENOMEM;
+
+        if (rx) {
+                ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
+                dp->dccps_hc_rx_ccid = new_ccid;
+                dp->dccps_options.dccpo_rx_ccid = new_ccid_nr;
+        } else {
+                ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+                dp->dccps_hc_tx_ccid = new_ccid;
+                dp->dccps_options.dccpo_tx_ccid = new_ccid_nr;
+        }
+
+        return 0;
+}
+
 /* XXX taking only u8 vals */
 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
 {
-        /* FIXME implement */
         dccp_pr_debug("changing [%d] feat %d to %d\n", type, feat, val);
+
+        switch (feat) {
+        case DCCPF_CCID:
+                return dccp_feat_update_ccid(sk, type, val);
+        default:
+                dccp_pr_debug("IMPLEMENT changing [%d] feat %d to %d\n",
+                              type, feat, val);
+                break;
+        }
         return 0;
 }