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| author | Hans Petter Selasky <hselasky@FreeBSD.org> | 2022-06-02 18:33:21 +0000 |
|---|---|---|
| committer | Hans Petter Selasky <hselasky@FreeBSD.org> | 2022-06-06 20:09:38 +0000 |
| commit | bc92b6240ddf6ab11813abe439653308da14ee54 (patch) | |
| tree | 9c426fe44ffe24a1bbf0b24ca6ded9b2fea7aa6f | |
| parent | 9feba5ab9023bac268f5f26fae1bc6d8ffbd49eb (diff) | |
| download | src-bc92b6240ddf6ab11813abe439653308da14ee54.tar.gz src-bc92b6240ddf6ab11813abe439653308da14ee54.zip | |
tcp: Correctly compute the retransmit length for all 64-bit platforms.
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.c | 15 | ||||
| -rw-r--r-- | sys/netinet/tcp_seq.h | 1 |
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)) |