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Make gif(4) nesting level and parallel tunnel support tunable at runtime

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via sysctl's.  The old #defines, MAX_GIF_NEST and XBONEHACK are
currently supported for backwards compatability, but will probably be
removed at some point in the future.
This commit is contained in:
Brooks Davis 2002-02-26 01:56:56 +00:00
parent 6f65a2bd46
commit 872f786a75
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=91270
2 changed files with 45 additions and 5 deletions
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18
share/man/man4/gif.4
View file

@ -153,6 +153,24 @@ Ingress filter can be turned off by
.Dv IFF_LINK2
bit.
.\"
.Pp
.Ss Miscellaneous
By default
.Nm
tunnels may not be nested.
This behavior may be modified at runtime by setting the
.Xr sysctl 8
variable
.Va net.link.gif.max_nesting
to the desired level of nesting.
Additionally,
.Nm
tunnels are restricted to one per pair of end points.
Parallel tunnels may be enabled by setting the
.Xr sysctl 8
variable
.Va net.link.gif.parallel_tunnels
to 1.
.Sh SEE ALSO
.Xr inet 4 ,
.Xr inet6 4 ,

32
sys/net/if_gif.c
View file

@ -42,6 +42,7 @@
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/protosw.h>
#include <sys/conf.h>
@ -123,9 +124,12 @@ struct ip6protosw in6_gif_protosw =
};
#endif
SYSCTL_DECL(_net_link);
SYSCTL_NODE(_net_link, IFT_GIF, gif, CTLFLAG_RW, 0,
"Generic Tunnel Interface");
#ifndef MAX_GIF_NEST
/*
* This macro controls the upper limitation on nesting of gif tunnels.
* This macro controls the default upper limitation on nesting of gif tunnels.
* Since, setting a large value to this macro with a careless configuration
* may introduce system crash, we don't allow any nestings by default.
* If you need to configure nested gif tunnels, you can define this macro
@ -135,6 +139,21 @@ struct ip6protosw in6_gif_protosw =
#define MAX_GIF_NEST 1
#endif
static int max_gif_nesting = MAX_GIF_NEST;
SYSCTL_INT(_net_link_gif, OID_AUTO, max_nesting, CTLFLAG_RW,
&max_gif_nesting, 0, "Max nested tunnels");
/*
* By default, we disallow creation of multiple tunnels between the same
* pair of addresses. Some applications require this functionality so
* we allow control over this check here.
*/
#ifdef XBONEHACK
static int parallel_tunnels = 1;
#else
static int parallel_tunnels = 0;
#endif
SYSCTL_INT(_net_link_gif, OID_AUTO, parallel_tunnels, CTLFLAG_RW,
&parallel_tunnels, 0, "Allow parallel tunnels?");
int
gif_clone_create(ifc, unit)
@ -659,14 +678,17 @@ gif_ioctl(ifp, cmd, data)
sc2->gif_psrc->sa_family != src->sa_family ||
sc2->gif_psrc->sa_len != src->sa_len)
continue;
#ifndef XBONEHACK
/* can't configure same pair of address onto two gifs */
if (bcmp(sc2->gif_pdst, dst, dst->sa_len) == 0 &&
/*
* Disallow parallel tunnels unless instructed
* otherwise.
*/
if (!parallel_tunnels &&
bcmp(sc2->gif_pdst, dst, dst->sa_len) == 0 &&
bcmp(sc2->gif_psrc, src, src->sa_len) == 0) {
error = EADDRNOTAVAIL;
goto bad;
}
#endif
/* can't configure multiple multi-dest interfaces */
#define multidest(x) \