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authorHans Petter Selasky <hselasky@FreeBSD.org>2022-06-02 18:33:21 +0000
committerHans Petter Selasky <hselasky@FreeBSD.org>2022-06-06 20:09:38 +0000
commitbc92b6240ddf6ab11813abe439653308da14ee54 (patch)
tree9c426fe44ffe24a1bbf0b24ca6ded9b2fea7aa6f
parent9feba5ab9023bac268f5f26fae1bc6d8ffbd49eb (diff)
downloadsrc-stable/11.tar.gz
src-stable/11.zip
tcp: Correctly compute the retransmit length for all 64-bit platforms.stable/11
When the TCP sequence number subtracted is greater than 2**32 minus the window size, or 2**31 minus the window size, the use of unsigned long as an intermediate variable, may result in an incorrect retransmit length computation on all 64-bit platforms. While at it create a helper macro to facilitate the computation of the difference between two TCP sequence numbers. Differential Revision: https://reviews.freebsd.org/D35388 Reviewed by: rscheff Sponsored by: NVIDIA Networking (cherry picked from commit 28173d49dccb91e50be9c401dbad1da908a5dc75)
-rw-r--r--sys/netinet/tcp_output.c15
-rw-r--r--sys/netinet/tcp_seq.h1
2 files changed, 10 insertions, 6 deletions
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index 53e3623e7616..cd12e2714d72 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -296,13 +296,16 @@ again:
*/
p = NULL;
goto after_sack_rexmit;
- } else
+ } else {
/* Can rexmit part of the current hole */
- len = ((long)ulmin(cwin,
- tp->snd_recover - p->rxmit));
- } else
- len = ((long)ulmin(cwin, p->end - p->rxmit));
- off = p->rxmit - tp->snd_una;
+ len = ((int32_t)ulmin(cwin,
+ SEQ_SUB(tp->snd_recover, p->rxmit)));
+ }
+ } else {
+ len = ((int32_t)ulmin(cwin,
+ SEQ_SUB(p->end, p->rxmit)));
+ }
+ off = SEQ_SUB(p->rxmit, tp->snd_una);
KASSERT(off >= 0,("%s: sack block to the left of una : %d",
__func__, off));
if (len > 0) {
diff --git a/sys/netinet/tcp_seq.h b/sys/netinet/tcp_seq.h
index ca1adbaaeab6..7a812e17cc54 100644
--- a/sys/netinet/tcp_seq.h
+++ b/sys/netinet/tcp_seq.h
@@ -41,6 +41,7 @@
#define SEQ_LEQ(a,b) ((int)((a)-(b)) <= 0)
#define SEQ_GT(a,b) ((int)((a)-(b)) > 0)
#define SEQ_GEQ(a,b) ((int)((a)-(b)) >= 0)
+#define SEQ_SUB(a,b) ((int)((a)-(b)))
#define SEQ_MIN(a, b) ((SEQ_LT(a, b)) ? (a) : (b))
#define SEQ_MAX(a, b) ((SEQ_GT(a, b)) ? (a) : (b))