path: root/net/dccp/feat.h
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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2011-07-24 20:22:29 -0600
committerGerrit Renker <gerrit@erg.abdn.ac.uk>2011-08-01 07:52:34 -0600
commitd6916f87ca5e566786f1a935a7cabba54774bbda (patch)
tree5420a242fe5f7aacf08e941a96cff8b173eec9aa /net/dccp/feat.h
parentMerge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6 (diff)
dccp: support for the exchange of NN options in established state 1/2
In contrast to static feature negotiation at the begin of a connection, this patch introduces support for exchange of dynamically changing options. Such an update/exchange is necessary in at least two cases: * CCID-2's Ack Ratio (RFC 4341, 6.1.2) which changes during the connection; * Sequence Window values that, as per RFC 4340, 7.5.2, should be sent "as the connection progresses". Both are non-negotiable (NN) features, which means that no new capabilities are negotiated, but rather that changes in known parameters are brought up-to-date at either end. Thse characteristics are reflected by the implementation: * only NN options can be exchanged after connection setup; * an ack is scheduled directly after activation to speed up the update; * CCIDs may request changes to an NN feature even if a negotiation for that feature is already underway: this is required by CCID-2, where changes in cwnd necessitate Ack Ratio changes, such that the previous Ack Ratio (which is still being negotiated) would cause irrecoverable RTO timeouts (thanks to work by Samuel Jero). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: Samuel Jero <sj323707@ohio.edu> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.uk>
Diffstat (limited to '')
1 files changed, 1 insertions, 0 deletions
diff --git a/net/dccp/feat.h b/net/dccp/feat.h
index e56a4e5e634e..90b957d34d26 100644
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
@@ -129,6 +129,7 @@ extern int dccp_feat_clone_list(struct list_head const *, struct list_head *);
extern void dccp_encode_value_var(const u64 value, u8 *to, const u8 len);
extern u64 dccp_decode_value_var(const u8 *bf, const u8 len);
+extern u64 dccp_feat_nn_get(struct sock *sk, u8 feat);
extern int dccp_insert_option_mandatory(struct sk_buff *skb);
extern int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,