[CCID2]: Use feature-negotiation to report Ack Ratio changes
This uses the new feature-negotiation framework to signal Ack Ratio changes,
as required by RFC 4341, sec. 6.1.2.
This raises some problems for CCID2 since it can at the moment not cope grace-
fully with Ack Ratio of e.g. 2. A FIXME has thus been added which reverts to
the previous policy of bypassing the Ack Ratio sysctl.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
Documentation/networking/dccp.txt | 4 +++-
net/dccp/minisocks.c | 12 ++++++++++++
net/dccp/proto.c | 1 -
3 files changed, 15 insertions(+), 2 deletions(-)
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -190,7 +190,6 @@ int dccp_init_sock(struct sock *sk, cons
dp->dccps_rate_last = jiffies;
dp->dccps_role = DCCP_ROLE_UNDEFINED;
dp->dccps_service = DCCP_SERVICE_CODE_IS_ABSENT;
- dp->dccps_l_ack_ratio = dp->dccps_r_ack_ratio = 1;
return 0;
}
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -323,10 +323,22 @@ int dccp_hdlr_seq_win(struct sock *sk, u
int dccp_hdlr_ack_ratio(struct sock *sk, u64 ratio, bool rx)
{
+#ifndef __CCID2_COPES_GRACEFULLY_WITH_DYNAMIC_ACK_RATIO_UPDATES__
+ /*
+ * FIXME: This hack is required to remain bug-compatible with CCID2.
+ * Using Ack Ratios > 1 lead to hangups and long RTO timeouts
+ * (1..3 seconds). CCID2 code needs to be fixed first before being
+ * able to use dynamic updates of Ack Ratio.
+ */
+ DCCP_WARN("Not changing %s Ack Ratio from 1 to %u\n", rx ? "RX" : "TX",
+ (u16)ratio);
+ dccp_sk(sk)->dccps_l_ack_ratio = dccp_sk(sk)->dccps_r_ack_ratio = 1;
+#else
if (rx)
dccp_sk(sk)->dccps_r_ack_ratio = ratio;
else
dccp_sk(sk)->dccps_l_ack_ratio = ratio;
+#endif
return 0;
}
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -144,7 +144,9 @@ send_ackvec = 1
Whether or not to send Ack Vector options (sec. 11.5).
ack_ratio = 2
- The default Ack Ratio (sec. 11.3) to use.
+ The default local (sender) Ack Ratio (sec. 11.3). This will only be used
+ if the active TX CCID supports it (currently only CCID2). The receiver
+ Ack Ratio is set automatically from the sender Ack Ratio of the peer.
seq_window = 100
The initial sequence window (sec. 7.5.2) of the sender. This influences
-
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