dccp: Set per-connection CCIDs via socket options

With this patch, TX/RX CCIDs can now be changed on a per-connection
basis, which overrides the defaults set by the global sysctl variables
for TX/RX CCIDs.

To make full use of this facility, the remaining patches of this patch
set are needed, which track dependencies and activate negotiated
feature values.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index eda389ce04f4..6a72ff52a8a4 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -168,6 +168,8 @@ enum {
         DCCPO_MIN_CCID_SPECIFIC = 128,
         DCCPO_MAX_CCID_SPECIFIC = 255,
 };
+/* maximum size of a single TLV-encoded DCCP option (sans type/len bytes) */
+#define DCCP_SINGLE_OPT_MAXLEN  253
 
 /* DCCP CCIDS */
 enum {
@@ -203,6 +205,9 @@ enum dccp_feature_numbers {
 #define DCCP_SOCKOPT_SEND_CSCOV         10
 #define DCCP_SOCKOPT_RECV_CSCOV         11
 #define DCCP_SOCKOPT_AVAILABLE_CCIDS    12
+#define DCCP_SOCKOPT_CCID               13
+#define DCCP_SOCKOPT_TX_CCID            14
+#define DCCP_SOCKOPT_RX_CCID            15
 #define DCCP_SOCKOPT_CCID_RX_INFO       128
 #define DCCP_SOCKOPT_CCID_TX_INFO       192