[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 <[EMAIL PROTECTED]>
---
Documentation/networking/dccp.txt | 14 ++++++++++++++
include/linux/dccp.h | 5 +++++
net/dccp/proto.c | 34 ++++++++++++++++++++++++++++++++++
3 files changed, 53 insertions(+)
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -61,6 +61,20 @@ DCCP_SOCKOPT_AVAILABLE_CCIDS is also rea
supported by the endpoint (see include/linux/dccp.h for symbolic constants).
The caller needs to provide a sufficiently large (> 2) array of type uint8_t.
+DCCP_SOCKOPT_CCID is write-only and sets both the TX and RX CCIDs at the same
+time, combining the operation of the next two socket options. This option is
+preferrable over the latter two, since often applications will use the same
+type of CCID for both directions, and mixed use of CCIDs is not currently well
+understood. This socket option takes as argument at least one uint8_t value, or
+an array of uint8_t values, which must match available CCIDS (see above). CCIDs
+must be registered before calling connect() or listen().
+
+DCCP_SOCKOPT_TX_CCID is read/write. It returns the current CCID (if set) or
sets
+the preference list for the TX CCID, using the same format as
DCCP_SOCKOPT_CCID.
+Please note that the getsockopt argument type is `int', not uint8_t.
+
+DCCP_SOCKOPT_RX_CCID is analogous to DCCP_SOCKOPT_TX_CCID, but for the RX CCID.
+
DCCP_SOCKOPT_SERVER_TIMEWAIT enables the server (listening socket) to hold
timewait state when closing the connection (RFC 4340, 8.3). The usual case is
that the closing server sends a CloseReq, whereupon the client holds timewait
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -213,11 +213,16 @@ struct dccp_so_feat {
#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
/* maximum number of services provided on the same listening port */
#define DCCP_SERVICE_LIST_MAX_LEN 32
+/* maximum number of CCID preferences that can be registered at one time */
+#define DCCP_CCID_LIST_MAX_LEN 16
#ifdef __KERNEL__
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -444,6 +444,36 @@ static int dccp_setsockopt_service(struc
return 0;
}
+static int dccp_setsockopt_ccid(struct sock *sk, int type,
+ char __user *optval, int optlen)
+{
+ u8 *val;
+ int rc = 0;
+
+ BUILD_BUG_ON(sizeof(u8) != 1);
+
+ if (optlen < 1 || optlen > DCCP_CCID_LIST_MAX_LEN)
+ return -EINVAL;
+
+ val = kmalloc(optlen, GFP_KERNEL);
+ if (val == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(val, optval, optlen))
+ rc = -EFAULT;
+
+ lock_sock(sk);
+ if (!rc && (type == DCCP_SOCKOPT_TX_CCID || type == DCCP_SOCKOPT_CCID))
+ rc = dccp_feat_register_change(sk, DCCPF_CCID, 1, val, optlen);
+
+ if (!rc && (type == DCCP_SOCKOPT_RX_CCID || type == DCCP_SOCKOPT_CCID))
+ rc = dccp_feat_register_change(sk, DCCPF_CCID, 0, val, optlen);
+ release_sock(sk);
+
+ kfree(val);
+ return rc;
+}
+
static int dccp_setsockopt_change(struct sock *sk, char __user *optval,
int optlen, bool is_local)
{
@@ -520,6 +550,10 @@ static int do_dccp_setsockopt(struct soc
return dccp_setsockopt_change(sk, optval, optlen, true);
case DCCP_SOCKOPT_CHANGE_R:
return dccp_setsockopt_change(sk, optval, optlen, false);
+ case DCCP_SOCKOPT_CCID:
+ case DCCP_SOCKOPT_RX_CCID:
+ case DCCP_SOCKOPT_TX_CCID:
+ return dccp_setsockopt_ccid(sk, optname, optval, optlen);
default:
if (optlen < sizeof(int))
return -EINVAL;
-
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