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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2008-07-13 11:51:40 +0100
committerGerrit Renker <gerrit@erg.abdn.ac.uk>2008-07-13 11:51:40 +0100
commit2013c7e35aeba39777f9b3eef8a70207b3931152 (patch)
tree5d63ce9f8c512ffd17b8084002e6dc0e0f998b84 /net/dccp/dccp.h
parent79d16385c7f287a33ea771c4dbe60ae43f791b49 (diff)
downloadlinux-2013c7e35aeba39777f9b3eef8a70207b3931152.tar.bz2
dccp ccid-3: Fix error in loss detection
The TFRC loss detection code used the wrong loss condition (RFC 4340, 7.7.1): * the difference between sequence numbers s1 and s2 instead of * the number of packets missing between s1 and s2 (one less than the distance). Since this condition appears in many places of the code, it has been put into a separate function, dccp_loss_free(). Further changes: ---------------- * tidied up incorrect typing (it was using `int' for u64/s64 types); * optimised conditional statements for common case of non-reordered packets; * rewrote comments/documentation to match the changes. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp/dccp.h')
-rw-r--r--net/dccp/dccp.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 1b2cea244e12..32617e0576cb 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -153,6 +153,21 @@ static inline u64 max48(const u64 seq1, const u64 seq2)
return after48(seq1, seq2) ? seq1 : seq2;
}
+/**
+ * dccp_loss_free - Evaluates condition for data loss from RFC 4340, 7.7.1
+ * @s1: start sequence number
+ * @s2: end sequence number
+ * @ndp: NDP count on packet with sequence number @s2
+ * Returns true if the sequence range s1...s2 has no data loss.
+ */
+static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp)
+{
+ s64 delta = dccp_delta_seqno(s1, s2);
+
+ BUG_TRAP(delta >= 0);
+ return (u64)delta <= ndp + 1;
+}
+
enum {
DCCP_MIB_NUM = 0,
DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */