From b774f2851a1f240375811c7dbc7167816896e28b Mon Sep 17 00:00:00 2001
From: jan <jan@openbsd.org>
Date: Tue, 7 Mar 2023 20:09:47 +0000
Subject: [PATCH] Avoid enabling TSO on interfaces which are already attached
 to a bridge.

with tweaks from claudio and deraadt

ok claudio, bluhm
---
 sbin/ifconfig/ifconfig.8 |  9 +++++++--
 sys/net/if.c             | 34 ++++++++++++++++++----------------
 sys/net/if.h             |  4 ++--
 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index 6bd446bb48d..beeb8e80219 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ifconfig.8,v 1.390 2023/02/27 14:53:38 jmc Exp $
+.\"	$OpenBSD: ifconfig.8,v 1.391 2023/03/07 20:09:47 jan Exp $
 .\"	$NetBSD: ifconfig.8,v 1.11 1996/01/04 21:27:29 pk Exp $
 .\"     $FreeBSD: ifconfig.8,v 1.16 1998/02/01 07:03:29 steve Exp $
 .\"
@@ -31,7 +31,7 @@
 .\"
 .\"     @(#)ifconfig.8	8.4 (Berkeley) 6/1/94
 .\"
-.Dd $Mdocdate: February 27 2023 $
+.Dd $Mdocdate: March 7 2023 $
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -501,6 +501,11 @@ such as
 .Xr aggr 4 ,
 and
 .Xr carp 4 .
+It is not possible to use TSO with interfaces attached to a
+.Xr bridge 4 ,
+.Xr veb 4 ,
+or
+.Xr tpmr 4 .
 Changing this option will re-initialize the network interface.
 .It Cm -tso
 Disable TSO.
diff --git a/sys/net/if.c b/sys/net/if.c
index 90a78d7f109..8ae59647204 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.684 2023/02/27 09:35:32 jan Exp $	*/
+/*	$OpenBSD: if.c,v 1.685 2023/03/07 20:09:48 jan Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -2058,18 +2058,9 @@ ifioctl(struct socket *so, u_long cmd, caddr_t data, struct proc *p)
 		}
 #endif
 
-		if (ISSET(ifp->if_capabilities, IFCAP_TSO) &&
-		    ISSET(ifr->ifr_flags, IFXF_TSO) !=
-		    ISSET(ifp->if_xflags, IFXF_TSO)) {
-			if (ISSET(ifr->ifr_flags, IFXF_TSO))
-				ifsettso(ifp, 1);
-			else
-				ifsettso(ifp, 0);
-		} else if (!ISSET(ifp->if_capabilities, IFCAP_TSO) &&
-		    ISSET(ifr->ifr_flags, IFXF_TSO)) {
-			ifr->ifr_flags &= ~IFXF_TSO;
-			error = ENOTSUP;
-		}
+		if (ISSET(ifr->ifr_flags, IFXF_TSO) !=
+		    ISSET(ifp->if_xflags, IFXF_TSO))
+			error = ifsettso(ifp, ISSET(ifr->ifr_flags, IFXF_TSO));
 
 		if (error == 0)
 			ifp->if_xflags = (ifp->if_xflags & IFXF_CANTCHANGE) |
@@ -3113,18 +3104,27 @@ ifpromisc(struct ifnet *ifp, int pswitch)
 }
 
 /* Set/clear TSO flag and restart interface if needed. */
-void
+int
 ifsettso(struct ifnet *ifp, int on)
 {
 	struct ifreq ifrq;
+	int error = 0;
 	int s = splnet();
 
 	NET_ASSERT_LOCKED();	/* for ioctl */
 	KERNEL_ASSERT_LOCKED();	/* for if_flags */
 
-	if (on && !ISSET(ifp->if_xflags, IFXF_TSO))
+	if (on && !ISSET(ifp->if_xflags, IFXF_TSO)) {
+		if (!ISSET(ifp->if_capabilities, IFCAP_TSO)) {
+			error = ENOTSUP;
+			goto out;
+		}
+		if (ether_brport_isset(ifp)) {
+			error = EBUSY;
+			goto out;
+		}
 		SET(ifp->if_xflags, IFXF_TSO);
-	else if (!on && ISSET(ifp->if_xflags, IFXF_TSO))
+	} else if (!on && ISSET(ifp->if_xflags, IFXF_TSO))
 		CLR(ifp->if_xflags, IFXF_TSO);
 	else
 		goto out;
@@ -3142,6 +3142,8 @@ ifsettso(struct ifnet *ifp, int on)
 	}
  out:
 	splx(s);
+
+	return error;
 }
 
 void
diff --git a/sys/net/if.h b/sys/net/if.h
index 6a046623747..757ff96f126 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.h,v 1.210 2023/02/27 09:35:32 jan Exp $	*/
+/*	$OpenBSD: if.h,v 1.211 2023/03/07 20:09:48 jan Exp $	*/
 /*	$NetBSD: if.h,v 1.23 1996/05/07 02:40:27 thorpej Exp $	*/
 
 /*
@@ -544,7 +544,7 @@ void	if_getdata(struct ifnet *, struct if_data *);
 void	ifinit(void);
 int	ifioctl(struct socket *, u_long, caddr_t, struct proc *);
 int	ifpromisc(struct ifnet *, int);
-void	ifsettso(struct ifnet *, int);
+int	ifsettso(struct ifnet *, int);
 struct	ifg_group *if_creategroup(const char *);
 int	if_addgroup(struct ifnet *, const char *);
 int	if_delgroup(struct ifnet *, const char *);
-- 
2.20.1