[DCCP]: Initialisation and type-checking of feature sysctls
The number of feature sysctls is now smaller (it is instead now possible
to set values on a per-connection basis via sockops); this patch takes care
of their initialisation and some rudimentary type-checking:
* Sequence Window uses the specified Wmin=32, the maximum is ulong (4 bytes), I have
tested and confirmed that it works up to 4294967295 - let's use it for Gbps;
* Ack Ratio is between 0 .. 0xFFFF (2-byte unsigned integer);
* CCIDs are between 0 .. 255 (FIXME: write handler for available ones);
* request_retries, retries1, retries2 also between 0..255 for good measure;
* tx_qlen is checked to be non-negative;
* sync_ratelimit remains as before.
The sysctls are initialised with the known default values for each feature
at boot or module load time; for the type-checking the value constraints from
RFC 4340 have been used. Type checking is important since some of the sysctls
now directly act on the feature-negotiation process.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
include/linux/dccp.h | 7 -------
net/dccp/dccp.h | 4 ----
net/dccp/feat.c | 12 ++++++++++++
net/dccp/feat.h | 10 ++++++++++
net/dccp/sysctl.c | 44 ++++++++++++++++++++++++++++++++------------
5 files changed, 54 insertions(+), 23 deletions(-)
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -95,10 +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_feat_ack_ratio;
extern int sysctl_dccp_tx_qlen;
extern int sysctl_dccp_sync_ratelimit;
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -368,13 +368,6 @@ static inline unsigned int dccp_hdr_len(
}
-/* 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_minisock - Minimal DCCP connection representation
*
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -88,6 +88,15 @@ struct ccid_dependency {
u8 val;
};
+/*
+ * Sysctls which determine global values for feature negotiation
+ */
+extern unsigned long sysctl_dccp_feat_sequence_window;
+extern int sysctl_dccp_feat_ack_ratio;
+extern int sysctl_dccp_feat_rx_ccid;
+extern int sysctl_dccp_feat_tx_ccid;
+extern int sysctl_dccp_feat_send_ndp_count;
+
#ifdef CONFIG_IP_DCCP_DEBUG
extern const char *dccp_feat_typename(const u8 type);
extern const char *dccp_feat_name(const u8 feat);
@@ -102,6 +111,7 @@ 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_change(struct sock *sk, u8 feat,
u8 is_local, u8 *val, u8 len);
extern int dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -1016,6 +1016,18 @@ int dccp_feat_parse_options(struct sock
return 0; /* ignore FN options in all other states */
}
+/* initialise sysctls with default values from the table */
+void __init dccp_feat_initialise_sysctls(void)
+{
+#define DCCP_FEAT_SYSCTL_INIT(var, feat) \
+ sysctl_dccp_feat_ ##var = dccp_feat_default_value(DCCPF_ ##feat)
+
+ DCCP_FEAT_SYSCTL_INIT(sequence_window, SEQUENCE_WINDOW);
+ DCCP_FEAT_SYSCTL_INIT(rx_ccid, CCID);
+ DCCP_FEAT_SYSCTL_INIT(tx_ccid, CCID);
+ DCCP_FEAT_SYSCTL_INIT(ack_ratio, ACK_RATIO);
+}
+
/**
* dccp_feat_init - Seed feature negotiation with host-specific defaults
* This initialises global defaults, depending on the value of the sysctls.
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
@@ -15,10 +15,10 @@
#include "feat.h"
/* sysctls related to initialisation of option values */
-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;
-int sysctl_dccp_feat_ack_ratio = DCCPF_INITIAL_ACK_RATIO;
+unsigned long sysctl_dccp_feat_sequence_window;
+int sysctl_dccp_feat_rx_ccid;
+int sysctl_dccp_feat_tx_ccid;
+int sysctl_dccp_feat_ack_ratio;
/* the maximum queue length for tx in packets. 0 is no limit */
int sysctl_dccp_tx_qlen __read_mostly = 5;
@@ -33,62 +33,81 @@ int sysctl_dccp_sync_ratelimit __read_mo
#ifdef CONFIG_SYSCTL
+static int zero = 0,
+ u8_max = 0xFF,
+ u16_max = 0xFFFF;
+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),
.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),
.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),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u8_max, /* RFC 4340, 10. */
},
{
.procname = "ack_ratio",
.data = &sysctl_dccp_feat_ack_ratio,
.maxlen = sizeof(sysctl_dccp_feat_ack_ratio),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &u16_max, /* RFC 4340, 11.3 */
},
{
.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",
@@ -135,6 +154,7 @@ static struct ctl_table_header *dccp_tab
int __init dccp_sysctl_init(void)
{
+ dccp_feat_initialise_sysctls();
dccp_table_header = register_sysctl_table(dccp_root_table);
return dccp_table_header != NULL ? 0 : -ENOMEM;
-
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