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Move "called", a static function variable used to detect recursive

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processing with gif interfaces, to a global variable named "gif_called".
Add an annotation that this approach will not work with a reentrant
network stack, and that we should instead use packet tags to detect
excessive recursive processing.
This commit is contained in:
Robert Watson 2004-03-22 14:24:26 +00:00
parent 77890ec33d
commit 523ebc4efe
1 changed files with 11 additions and 4 deletions
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15
sys/net/if_gif.c
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@ -86,6 +86,14 @@
static MALLOC_DEFINE(M_GIF, "gif", "Generic Tunnel Interface"); static MALLOC_DEFINE(M_GIF, "gif", "Generic Tunnel Interface");
static LIST_HEAD(, gif_softc) gif_softc_list; static LIST_HEAD(, gif_softc) gif_softc_list;
/*
* XXX: gif_called is a recursion counter to prevent misconfiguration to
* cause unbounded looping in the network stack. However, this is a flawed
* approach as it assumes non-reentrance in the stack. This should be
* changed to use packet tags to track recusion..
*/
static int gif_called = 0;
void (*ng_gif_input_p)(struct ifnet *ifp, struct mbuf **mp, int af); void (*ng_gif_input_p)(struct ifnet *ifp, struct mbuf **mp, int af);
void (*ng_gif_input_orphan_p)(struct ifnet *ifp, struct mbuf *m, int af); void (*ng_gif_input_orphan_p)(struct ifnet *ifp, struct mbuf *m, int af);
void (*ng_gif_attach_p)(struct ifnet *ifp); void (*ng_gif_attach_p)(struct ifnet *ifp);
@ -314,7 +322,6 @@ gif_output(ifp, m, dst, rt)
{ {
struct gif_softc *sc = (struct gif_softc*)ifp; struct gif_softc *sc = (struct gif_softc*)ifp;
int error = 0; int error = 0;
static int called = 0; /* XXX: MUTEX */
#ifdef MAC #ifdef MAC
error = mac_check_ifnet_transmit(ifp, m); error = mac_check_ifnet_transmit(ifp, m);
@ -331,10 +338,10 @@ gif_output(ifp, m, dst, rt)
* mutual exclusion of the variable CALLED, especially if we * mutual exclusion of the variable CALLED, especially if we
* use kernel thread. * use kernel thread.
*/ */
if (++called > max_gif_nesting) { if (++gif_called > max_gif_nesting) {
log(LOG_NOTICE, log(LOG_NOTICE,
"gif_output: recursively called too many times(%d)\n", "gif_output: recursively called too many times(%d)\n",
called); gif_called);
m_freem(m); m_freem(m);
error = EIO; /* is there better errno? */ error = EIO; /* is there better errno? */
goto end; goto end;
@ -378,7 +385,7 @@ gif_output(ifp, m, dst, rt)
} }
end: end:
called = 0; /* reset recursion counter */ gif_called = 0; /* reset recursion counter */
if (error) if (error)
ifp->if_oerrors++; ifp->if_oerrors++;
return error; return error;