On Mon, Apr 17, 2023 at 04:32:13PM +0200, Alexander Bluhm wrote:
> On Mon, Apr 17, 2023 at 02:36:57AM +0300, Vitaliy Makkoveev wrote:
> > It seems rt_setsource() needs some attention, but sysctl_source() could
> > be called with shared netlock just now.
>
> I think rtable_setsource() is not MP safe. It is documented as [K]
> kernel lock. But that is not true and makes no sense. It should
> be exclusive netlock. in_pcbselsrc() calls rtable_getsource() with
> netlock. We should rename source to ar_source so we can grep for
> its users.
Perhaps something like this. I will run it through regress.
Index: net/art.h
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/art.h,v
retrieving revision 1.21
diff -u -p -r1.21 art.h
--- net/art.h 2 Mar 2021 17:50:41 -0000 1.21
+++ net/art.h 17 Apr 2023 14:48:46 -0000
@@ -41,7 +41,7 @@ struct art_root {
uint8_t ar_nlvl; /* [I] Number of levels */
uint8_t ar_alen; /* [I] Address length in bits */
uint8_t ar_off; /* [I] Offset of key in bytes */
- struct sockaddr *source; /* [K] optional src addr to use
*/
+ struct sockaddr *ar_source; /* [N] use optional src addr */
};
#define ISLEAF(e) (((unsigned long)(e) & 1) == 0)
Index: net/rtable.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/rtable.c,v
retrieving revision 1.80
diff -u -p -r1.80 rtable.c
--- net/rtable.c 29 Jun 2022 22:20:47 -0000 1.80
+++ net/rtable.c 17 Apr 2023 14:54:52 -0000
@@ -376,10 +376,12 @@ rtable_setsource(unsigned int rtableid,
{
struct art_root *ar;
+ NET_ASSERT_LOCKED_EXCLUSIVE();
+
if ((ar = rtable_get(rtableid, af)) == NULL)
return (EAFNOSUPPORT);
- ar->source = src;
+ ar->ar_source = src;
return (0);
}
@@ -389,11 +391,13 @@ rtable_getsource(unsigned int rtableid,
{
struct art_root *ar;
+ NET_ASSERT_LOCKED();
+
ar = rtable_get(rtableid, af);
if (ar == NULL)
return (NULL);
- return (ar->source);
+ return (ar->ar_source);
}
void
Index: net/rtsock.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/net/rtsock.c,v
retrieving revision 1.359
diff -u -p -r1.359 rtsock.c
--- net/rtsock.c 22 Jan 2023 12:05:44 -0000 1.359
+++ net/rtsock.c 17 Apr 2023 15:16:48 -0000
@@ -853,8 +853,10 @@ route_output(struct mbuf *m, struct sock
error = EINVAL;
goto fail;
}
- if ((error =
- rt_setsource(tableid, info.rti_info[RTAX_IFA])) != 0)
+ NET_LOCK();
+ error = rt_setsource(tableid, info.rti_info[RTAX_IFA]);
+ NET_UNLOCK();
+ if (error)
goto fail;
} else {
error = rtm_output(rtm, &rt, &info, prio, tableid);
@@ -862,7 +864,9 @@ route_output(struct mbuf *m, struct sock
type = rtm->rtm_type;
seq = rtm->rtm_seq;
free(rtm, M_RTABLE, len);
+ NET_LOCK_SHARED();
rtm = rtm_report(rt, type, seq, tableid);
+ NET_UNLOCK_SHARED();
len = rtm->rtm_msglen;
}
}
