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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2009-01-16 23:36:32 +0000
committerDavid S. Miller <davem@davemloft.net>2009-01-21 14:34:05 -0800
commit883ca833e5fb814fb03426c9d35e5489ce43e8da (patch)
treedcf361291b79e57195f8d89ca493c15c835b14cf /net/dccp/feat.c
parent792b48780e8b6435d017cef4b5c304876a48653e (diff)
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@sysctl_dccp_feat@sysctl_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@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/feat.c')
-rw-r--r--net/dccp/feat.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 7303f79705d2..12006e9b2472 100644
--- 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);

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