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tcp: Avoid division by zero when KERN_TLS is enabled in tcp_account_for_send().

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If the "len" variable is non-zero, we can assume that the sum of
"tp->t_snd_rxt_bytes + tp->t_sndbytes" is also non-zero.

It is also assumed that the 64-bit byte counters will never wrap around.

Differential Revision:	https://reviews.freebsd.org/D31959
Reviewed by:	gallatin, rrs and tuexen
Found by:	"I told you so", also called hselasky
MFC after:	1 week
Sponsored by:	NVIDIA Networking
This commit is contained in:
Hans Petter Selasky 2021-09-15 18:03:38 +02:00
parent 857dc1c0ec
commit e3e7d95332
1 changed files with 1 additions and 1 deletions

2
sys/netinet/tcp_var.h

@ -1155,7 +1155,7 @@ tcp_account_for_send(struct tcpcb *tp, uint32_t len, uint8_t is_rxt,
tp->t_sndbytes += len;
#ifdef KERN_TLS
if (hw_tls && is_rxt) {
if (hw_tls && is_rxt && len != 0) {
uint64_t rexmit_percent = (1000ULL * tp->t_snd_rxt_bytes) / (10ULL * (tp->t_snd_rxt_bytes + tp->t_sndbytes));
if (rexmit_percent > ktls_ifnet_max_rexmit_pct)
ktls_disable_ifnet(tp);