From: Alexander Bluhm <bluhm@openbsd.org>
Subject: sysctl export TCP snd_cwnd for netstat -B
To: tech@openbsd.org
Date: Tue, 3 Jun 2025 21:49:27 +0200

Hi,

Export TCP send congestion window in sysctl fill_file() also for
inet6 so netstat -B can show it.  Looks like an oversight.  While
there replace cast with common macro.

Proto   Recv-Q Send-Q Recv-W Send-W Cgst-W  Local Address          Foreign Address        TCP-State
before:
tcp6         0     44  17136  16384      0  fe80::725f:caff:.ssh   fe80::fce1:baff:.11120 ESTABLISHED
after:
tcp6         0     60  17136  16384  29988  fe80::725f:caff:.ssh   fe80::fce1:baff:.41587 ESTABLISHED

ok?

bluhm

Index: kern/kern_sysctl.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/kern_sysctl.c,v
diff -u -p -r1.472 kern_sysctl.c
--- kern/kern_sysctl.c	3 Jun 2025 17:32:42 -0000	1.472
+++ kern/kern_sysctl.c	3 Jun 2025 19:39:35 -0000
@@ -1576,7 +1576,8 @@ fill_file(struct kinfo_file *kf, struct 
 			if (so->so_type == SOCK_RAW)
 				kf->inp_proto = inpcb->inp_ip.ip_p;
 			if (so->so_proto->pr_protocol == IPPROTO_TCP) {
-				struct tcpcb *tcpcb = (void *)inpcb->inp_ppcb;
+				struct tcpcb *tcpcb = intotcpcb(inpcb);
+
 				kf->t_rcv_wnd = tcpcb->rcv_wnd;
 				kf->t_snd_wnd = tcpcb->snd_wnd;
 				kf->t_snd_cwnd = tcpcb->snd_cwnd;
@@ -1604,9 +1605,11 @@ fill_file(struct kinfo_file *kf, struct 
 			if (so->so_type == SOCK_RAW)
 				kf->inp_proto = inpcb->inp_ipv6.ip6_nxt;
 			if (so->so_proto->pr_protocol == IPPROTO_TCP) {
-				struct tcpcb *tcpcb = (void *)inpcb->inp_ppcb;
+				struct tcpcb *tcpcb = intotcpcb(inpcb);
+
 				kf->t_rcv_wnd = tcpcb->rcv_wnd;
 				kf->t_snd_wnd = tcpcb->snd_wnd;
+				kf->t_snd_cwnd = tcpcb->snd_cwnd;
 				kf->t_state = tcpcb->t_state;
 			}
 			break;