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dccp: Set per-connection CCIDs via socket options

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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>
This commit is contained in:
Gerrit Renker 2008-11-23 16:02:31 -08:00 committed by David S. Miller
parent 2c62ad7b56
commit b20a9c24d5
6 changed files with 61 additions and 8 deletions
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14
Documentation/networking/dccp.txt
View file

@ -61,6 +61,20 @@ DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs
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 on the socket 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 here 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

5
include/linux/dccp.h
View file

@ -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

9
net/dccp/ackvec.c
View file

@ -12,7 +12,6 @@
#include "ackvec.h"
#include "dccp.h"
#include <linux/dccp.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel.h>
@ -68,7 +67,7 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
struct dccp_sock *dp = dccp_sk(sk);
struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
/* Figure out how many options do we need to represent the ackvec */
const u16 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_MAX_ACKVEC_OPT_LEN);
const u8 nr_opts = DIV_ROUND_UP(av->av_vec_len, DCCP_SINGLE_OPT_MAXLEN);
u16 len = av->av_vec_len + 2 * nr_opts, i;
u32 elapsed_time;
const unsigned char *tail, *from;
@ -100,8 +99,8 @@ int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
for (i = 0; i < nr_opts; ++i) {
int copylen = len;
if (len > DCCP_MAX_ACKVEC_OPT_LEN)
copylen = DCCP_MAX_ACKVEC_OPT_LEN;
if (len > DCCP_SINGLE_OPT_MAXLEN)
copylen = DCCP_SINGLE_OPT_MAXLEN;
*to++ = DCCPO_ACK_VECTOR_0;
*to++ = copylen + 2;
@ -432,7 +431,7 @@ static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av,
int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
u64 *ackno, const u8 opt, const u8 *value, const u8 len)
{
if (len > DCCP_MAX_ACKVEC_OPT_LEN)
if (len > DCCP_SINGLE_OPT_MAXLEN)
return -1;
/* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */

5
net/dccp/ackvec.h
View file

@ -11,15 +11,14 @@
* published by the Free Software Foundation.
*/
#include <linux/dccp.h>
#include <linux/compiler.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/types.h>
/* Read about the ECN nonce to see why it is 253 */
#define DCCP_MAX_ACKVEC_OPT_LEN 253
/* We can spread an ack vector across multiple options */
#define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 2)
#define DCCP_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * 2)
#define DCCP_ACKVEC_STATE_RECEIVED 0
#define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6)

2
net/dccp/feat.h
View file

@ -22,6 +22,8 @@
/* Wmin=32 and Wmax=2^46-1 from 7.5.2 */
#define DCCPF_SEQ_WMIN 32
#define DCCPF_SEQ_WMAX 0x3FFFFFFFFFFFull
/* Maximum number of SP values that fit in a single (Confirm) option */
#define DCCP_FEAT_MAX_SP_VALS (DCCP_SINGLE_OPT_MAXLEN - 2)
enum dccp_feat_type {
FEAT_AT_RX = 1, /* located at RX side of half-connection */

34
net/dccp/proto.c
View file

@ -501,6 +501,36 @@ static int dccp_setsockopt_cscov(struct sock *sk, int cscov, bool rx)
return rc;
}
static int dccp_setsockopt_ccid(struct sock *sk, int type,
char __user *optval, int optlen)
{
u8 *val;
int rc = 0;
if (optlen < 1 || optlen > DCCP_FEAT_MAX_SP_VALS)
return -EINVAL;
val = kmalloc(optlen, GFP_KERNEL);
if (val == NULL)
return -ENOMEM;
if (copy_from_user(val, optval, optlen)) {
kfree(val);
return -EFAULT;
}
lock_sock(sk);
if (type == DCCP_SOCKOPT_TX_CCID || type == DCCP_SOCKOPT_CCID)
rc = dccp_feat_register_sp(sk, DCCPF_CCID, 1, val, optlen);
if (!rc && (type == DCCP_SOCKOPT_RX_CCID || type == DCCP_SOCKOPT_CCID))
rc = dccp_feat_register_sp(sk, DCCPF_CCID, 0, val, optlen);
release_sock(sk);
kfree(val);
return rc;
}
static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, int optlen)
{
@ -515,6 +545,10 @@ static int do_dccp_setsockopt(struct sock *sk, int level, int optname,
case DCCP_SOCKOPT_CHANGE_R:
DCCP_WARN("sockopt(CHANGE_L/R) is deprecated: fix your app\n");
return 0;
case DCCP_SOCKOPT_CCID:
case DCCP_SOCKOPT_RX_CCID:
case DCCP_SOCKOPT_TX_CCID:
return dccp_setsockopt_ccid(sk, optname, optval, optlen);
}
if (optlen < (int)sizeof(int))