From: Alexander Bluhm <bluhm@openbsd.org>
Subject: Re: tcp const variables
To: Vitaliy Makkoveev <otto@bsdbox.dev>
Cc: OpenBSD tech <tech@openbsd.org>
Date: Thu, 26 Dec 2024 12:33:01 +0100

On Thu, Dec 26, 2024 at 03:10:16AM +0300, Vitaliy Makkoveev wrote:
> I'm interesting about behaviour after we changed const sb_max in
> ddb(4).

You are right, ddb does not like writing to sb_max.  Better mark
sb_max as initialized.

ok?

bluhm

Index: kern/uipc_socket2.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/kern/uipc_socket2.c,v
diff -u -p -r1.160 uipc_socket2.c
--- kern/uipc_socket2.c	19 Dec 2024 22:11:35 -0000	1.160
+++ kern/uipc_socket2.c	26 Dec 2024 11:21:32 -0000
@@ -47,7 +47,7 @@
  * Primitive routines for operating on sockets and socket buffers
  */
 
-u_long	sb_max = SB_MAX;		/* patchable */
+u_long sb_max = SB_MAX;		/* [I] patchable */
 
 extern struct pool mclpools[];
 extern struct pool mbpool;
Index: netinet/tcp_input.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/tcp_input.c,v
diff -u -p -r1.412 tcp_input.c
--- netinet/tcp_input.c	24 Dec 2024 19:16:53 -0000	1.412
+++ netinet/tcp_input.c	26 Dec 2024 11:20:59 -0000
@@ -108,8 +108,8 @@ int tcp_flush_queue(struct tcpcb *);
 #include <netinet6/nd6.h>
 #endif /* INET6 */
 
-int	tcprexmtthresh = 3;
-int	tcptv_keep_init = TCPTV_KEEP_INIT;
+const int tcprexmtthresh = 3;
+int tcptv_keep_init = TCPTV_KEEP_INIT;
 
 int tcp_rst_ppslim = 100;		/* 100pps */
 int tcp_rst_ppslim_count = 0;
Index: netinet/tcp_output.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/tcp_output.c,v
diff -u -p -r1.146 tcp_output.c
--- netinet/tcp_output.c	19 Dec 2024 22:11:35 -0000	1.146
+++ netinet/tcp_output.c	26 Dec 2024 11:20:59 -0000
@@ -103,8 +103,6 @@
 extern struct mbuf *m_copypack();
 #endif
 
-extern int tcprexmtthresh;
-
 #ifdef TCP_SACK_DEBUG
 void tcp_print_holes(struct tcpcb *tp);
 
Index: netinet/tcp_var.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/tcp_var.h,v
diff -u -p -r1.179 tcp_var.h
--- netinet/tcp_var.h	26 Dec 2024 10:15:27 -0000	1.179
+++ netinet/tcp_var.h	26 Dec 2024 11:20:59 -0000
@@ -678,6 +678,7 @@ extern	const struct pr_usrreqs tcp6_usrr
 extern	struct pool tcpcb_pool;
 extern	struct inpcbtable tcbtable, tcb6table;	/* queue of active tcpcb's */
 extern	int tcp_do_rfc1323;	/* enabled/disabled? */
+extern	const int tcprexmtthresh;
 extern	int tcptv_keep_init;	/* [N] time to keep alive initial SYN packet */
 extern	int tcp_mssdflt;	/* [a] default maximum segment size */
 extern	int tcp_rst_ppslim;	/* maximum outgoing RST packet per second */