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Message-Id: <1232184993-9927-4-git-send-email-gerrit@erg.abdn.ac.uk>
Date: Sat, 17 Jan 2009 10:36:32 +0100
From: Gerrit Renker <gerrit@....abdn.ac.uk>
To: davem@...emloft.net
Cc: dccp@...r.kernel.org, netdev@...r.kernel.org,
Gerrit Renker <gerrit@....abdn.ac.uk>
Subject: [PATCH 3/4] dccp: Initialisation and type-checking of feature sysctls
This patch takes care of initialising and type-checking sysctls related to
feature negotiation. Type checking is important since some of the sysctls
now directly impact the feature-negotiation process.
The sysctls are initialised with the known default values for each feature.
For the type-checking the value constraints from RFC 4340 are used:
* Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes),
tested and confirmed that it works up to 4294967295 - for Gbps speed;
* Ack Ratio is between 0 .. 0xffff (2-byte unsigned integer);
* CCIDs are between 0 .. 255;
* request_retries, retries1, retries2 also between 0..255 for good measure;
* tx_qlen is checked to be non-negative;
* sync_ratelimit remains as before.
Notes:
------
1. Die s@...ctl_dccp_feat@...ctl_dccp@g since the sysctls are now in feat.c.
2. As pointed out by Arnaldo, the pattern of type-checking repeats itself in
other places, sometimes with exactly the same kind of definitions (e.g.
"static int zero;"). It may be a good idea (kernel janitors?) to consolidate
type checking. For the sake of keeping the changeset small and in order not
to affect other subsystems, I have not strived to generalise here.
Signed-off-by: Gerrit Renker <gerrit@....abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@...di.co.nz>
---
include/linux/dccp.h | 8 --------
net/dccp/dccp.h | 3 ---
net/dccp/feat.c | 11 ++++++++---
net/dccp/feat.h | 8 ++++++++
net/dccp/options.c | 4 ----
net/dccp/sysctl.c | 43 ++++++++++++++++++++++++++++++-------------
6 files changed, 46 insertions(+), 31 deletions(-)
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -100,6 +100,13 @@ struct ccid_dependency {
u8 val;
};
+/*
+ * Sysctls to seed defaults for feature negotiation
+ */
+extern unsigned long sysctl_dccp_sequence_window;
+extern int sysctl_dccp_rx_ccid;
+extern int sysctl_dccp_tx_ccid;
+
#ifdef CONFIG_IP_DCCP_DEBUG
extern const char *dccp_feat_typename(const u8 type);
extern const char *dccp_feat_name(const u8 feat);
@@ -114,6 +121,7 @@ static inline void dccp_feat_debug(const
#endif /* CONFIG_IP_DCCP_DEBUG */
extern int dccp_feat_init(struct sock *sk);
+extern void dccp_feat_initialise_sysctls(void);
extern int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
u8 const *list, u8 len);
extern int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -25,6 +25,11 @@
#include "ccid.h"
#include "feat.h"
+/* feature-specific sysctls - initialised to the defaults from RFC 4340, 6.4 */
+unsigned long sysctl_dccp_sequence_window __read_mostly = 100;
+int sysctl_dccp_rx_ccid __read_mostly = 2,
+ sysctl_dccp_tx_ccid __read_mostly = 2;
+
/*
* Feature activation handlers.
*
@@ -1146,7 +1151,7 @@ int dccp_feat_init(struct sock *sk)
/* Non-negotiable (NN) features */
rc = __feat_register_nn(fn, DCCPF_SEQUENCE_WINDOW, 0,
- sysctl_dccp_feat_sequence_window);
+ sysctl_dccp_sequence_window);
if (rc)
return rc;
@@ -1172,8 +1177,8 @@ int dccp_feat_init(struct sock *sk)
ccid_get_builtin_ccids(&rx.val, &rx.len))
return -ENOBUFS;
- if (!dccp_feat_prefer(sysctl_dccp_feat_tx_ccid, tx.val, tx.len) ||
- !dccp_feat_prefer(sysctl_dccp_feat_rx_ccid, rx.val, rx.len))
+ if (!dccp_feat_prefer(sysctl_dccp_tx_ccid, tx.val, tx.len) ||
+ !dccp_feat_prefer(sysctl_dccp_rx_ccid, rx.val, rx.len))
goto free_ccid_lists;
rc = __feat_register_sp(fn, DCCPF_CCID, true, false, tx.val, tx.len);
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
@@ -18,55 +18,72 @@
#error This file should not be compiled without CONFIG_SYSCTL defined
#endif
+/* Boundary values */
+static int zero = 0,
+ u8_max = 0xFF;
+static unsigned long seqw_min = 32;
+
static struct ctl_table dccp_default_table[] = {
{
.procname = "seq_window",
- .data = &sysctl_dccp_feat_sequence_window,
- .maxlen = sizeof(sysctl_dccp_feat_sequence_window),
+ .data = &sysctl_dccp_sequence_window,
+ .maxlen = sizeof(sysctl_dccp_sequence_window),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_doulongvec_minmax,
+ .extra1 = &seqw_min, /* RFC 4340, 7.5.2 */
},
{
.procname = "rx_ccid",
- .data = &sysctl_dccp_feat_rx_ccid,
- .maxlen = sizeof(sysctl_dccp_feat_rx_ccid),
+ .data = &sysctl_dccp_rx_ccid,
+ .maxlen = sizeof(sysctl_dccp_rx_ccid),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u8_max, /* RFC 4340, 10. */
},
{
.procname = "tx_ccid",
- .data = &sysctl_dccp_feat_tx_ccid,
- .maxlen = sizeof(sysctl_dccp_feat_tx_ccid),
+ .data = &sysctl_dccp_tx_ccid,
+ .maxlen = sizeof(sysctl_dccp_tx_ccid),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u8_max, /* RFC 4340, 10. */
},
{
.procname = "request_retries",
.data = &sysctl_dccp_request_retries,
.maxlen = sizeof(sysctl_dccp_request_retries),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u8_max,
},
{
.procname = "retries1",
.data = &sysctl_dccp_retries1,
.maxlen = sizeof(sysctl_dccp_retries1),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u8_max,
},
{
.procname = "retries2",
.data = &sysctl_dccp_retries2,
.maxlen = sizeof(sysctl_dccp_retries2),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u8_max,
},
{
.procname = "tx_qlen",
.data = &sysctl_dccp_tx_qlen,
.maxlen = sizeof(sysctl_dccp_tx_qlen),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
},
{
.procname = "sync_ratelimit",
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -355,14 +355,6 @@ static inline unsigned int dccp_hdr_len(
return __dccp_hdr_len(dccp_hdr(skb));
}
-
-/* initial values for each feature */
-#define DCCPF_INITIAL_SEQUENCE_WINDOW 100
-#define DCCPF_INITIAL_ACK_RATIO 2
-#define DCCPF_INITIAL_CCID DCCPC_CCID2
-/* FIXME: for now we're default to 1 but it should really be 0 */
-#define DCCPF_INITIAL_SEND_NDP_COUNT 1
-
/**
* struct dccp_request_sock - represent DCCP-specific connection request
* @dreq_inet_rsk: structure inherited from
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -95,9 +95,6 @@ extern void dccp_time_wait(struct sock *
extern int sysctl_dccp_request_retries;
extern int sysctl_dccp_retries1;
extern int sysctl_dccp_retries2;
-extern int sysctl_dccp_feat_sequence_window;
-extern int sysctl_dccp_feat_rx_ccid;
-extern int sysctl_dccp_feat_tx_ccid;
extern int sysctl_dccp_tx_qlen;
extern int sysctl_dccp_sync_ratelimit;
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -23,10 +23,6 @@
#include "dccp.h"
#include "feat.h"
-int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
-int sysctl_dccp_feat_rx_ccid = DCCPF_INITIAL_CCID;
-int sysctl_dccp_feat_tx_ccid = DCCPF_INITIAL_CCID;
-
u64 dccp_decode_value_var(const u8 *bf, const u8 len)
{
u64 value = 0;
--
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