On Fri, Oct 30, 2015 at 12:29:27PM +0100, Mike Belopuhov wrote:
> On Fri, Oct 30, 2015 at 12:29 +0100, Mike Belopuhov wrote:
> > On Fri, Oct 30, 2015 at 12:19 +0100, Reyk Floeter wrote:
> > > On Fri, Oct 30, 2015 at 11:30:56AM +0100, Alexander Bluhm wrote:
> > > > On Fri, Oct 30, 2015 at 10:43:21AM +0100, Reyk Floeter wrote:
> > > > > Question:
> > > > > > How does pair(4) interact with pf? If a packet crosses a pair
> > > > > > does it create a new state or does pf track the original state?
> > > > > >
> > > > >
> > > > > Answer:
> > > > > It does create a new state, you can filter between pair(4) without
> > > > > problems and all features including nat work.
> > > > > But it currently does not clear some of the extended packet settings -
> > > > > like flags, tags, qid etc. - so you can filter on the tag, eg.
> > > > >
> > > > > # Assuming pair1 is patched to pair0
> > > > > pass out on pair1 tag FOO
> > > > > pass in on pair0 tagged FOO
> > > > >
> > > > > The attached diff _removes_ that and resets all pf settings, so the pf
> > > > > rules above will not work anymore. I think it is better to assume
> > > > > crossing barriers and receiving packets with pair(4) works like a
> > > > > "normal" Ethernet packet. The following will still work:
> > > > >
> > > > > # Received packets on pair0 don't carry any existing pf states
> > > > > pass out on pair1
> > > > > pass in on pair0
> > > > >
> > > > > OK?
> > > >
> > > > The new semantics is better.
> > > >
> > > > > +void
> > > > > +pf_pkt_reset(struct mbuf *m)
> > > > > +{
> > > > > + if (m->m_flags & M_PKTHDR)
> > > > > + m_tag_delete_chain(m);
> > > > > +
> > > > > + /* resets state key, pcb reference, qid, tag, and all flags */
> > > > > + memset(&m->m_pkthdr.pf, 0, sizeof(m->m_pkthdr.pf));
> > > > > +}
> > > >
> > > > You need a packet header mbuf to access m->m_pkthdr. So either
> > > > assume that M_PKTHDR is set and don't check. Or put both actions
> > > > into the if block.
> > > >
> > > > As pf_pkt_addr_changed() accesses the m->m_pkthdr without check, I
> > > > would recomend to remove the "if (m->m_flags & M_PKTHDR)" here,
> > > > too. You may also put an assert into both functions.
> > > >
> > > > The default for m->m_pkthdr.pf.prio is IFQ_DEFPRIO, not 0.
> > > > Look at m_inithdr().
> > > >
> > >
> > > Thanks.
> > >
> > > Adding asserts in in both functions makes sense, but I'll try it
> > > separately - no caller of pf_pkt_addr_changed() checks for the pkthdr
> > > at the moment and I fear potential fallout. Maybe it would also make
> > > sense to rename both functions to pf_pkthdr_* to make it clear, but
> > > this can also be done separately.
> > >
> > > Here is the updated diff, OK?
> > >
> > > Reyk
> > >
> >
> > As I've told Reyk privately, since this function removes all
> > mbufs including IPsec ones, etc. it should not be part of pf,
> > but part of mbuf source code.
>
> mbuf *tags*
I think pf does handle packet mangling in various ways, which would
include the intended removal of other tags, but I don't care.
Here is the updated diff.
OK?
Index: sys/kern/uipc_mbuf.c
===================================================================
RCS file: /cvs/src/sys/kern/uipc_mbuf.c,v
retrieving revision 1.208
diff -u -p -r1.208 uipc_mbuf.c
--- sys/kern/uipc_mbuf.c 22 Oct 2015 05:26:06 -0000 1.208
+++ sys/kern/uipc_mbuf.c 30 Oct 2015 11:30:32 -0000
@@ -250,6 +250,18 @@ m_inithdr(struct mbuf *m)
return (m);
}
+void
+m_resethdr(struct mbuf *m)
+{
+ /* like the previous, but keep any associated data and mbufs */
+ m->m_flags = M_PKTHDR;
+ memset(&m->m_pkthdr.pf, 0, sizeof(m->m_pkthdr.pf));
+ m->m_pkthdr.pf.prio = IFQ_DEFPRIO;
+
+ /* also delete all mbuf tags to reset the state */
+ m_tag_delete_chain(m);
+}
+
struct mbuf *
m_getclr(int nowait, int type)
{
Index: sys/sys/mbuf.h
===================================================================
RCS file: /cvs/src/sys/sys/mbuf.h,v
retrieving revision 1.198
diff -u -p -r1.198 mbuf.h
--- sys/sys/mbuf.h 22 Oct 2015 05:26:06 -0000 1.198
+++ sys/sys/mbuf.h 30 Oct 2015 11:30:33 -0000
@@ -410,6 +410,7 @@ struct mbuf *m_get(int, int);
struct mbuf *m_getclr(int, int);
struct mbuf *m_gethdr(int, int);
struct mbuf *m_inithdr(struct mbuf *);
+void m_resethdr(struct mbuf *);
int m_defrag(struct mbuf *, int);
struct mbuf *m_prepend(struct mbuf *, int, int);
struct mbuf *m_pulldown(struct mbuf *, int, int, int *);
Index: sys/net/if_pair.c
===================================================================
RCS file: /cvs/src/sys/net/if_pair.c,v
retrieving revision 1.4
diff -u -p -r1.4 if_pair.c
--- sys/net/if_pair.c 25 Oct 2015 12:59:57 -0000 1.4
+++ sys/net/if_pair.c 30 Oct 2015 11:30:33 -0000
@@ -30,6 +30,11 @@
#include <netinet/in.h>
#include <netinet/if_ether.h>
+#include "pf.h"
+#if NPF > 0
+#include <net/pfvar.h>
+#endif
+
#include "bpfilter.h"
#if NBPFILTER > 0
#include <net/bpf.h>
@@ -182,9 +187,13 @@ pairstart(struct ifnet *ifp)
#endif /* NBPFILTER > 0 */
ifp->if_opackets++;
- if (pairedifp != NULL)
+ if (pairedifp != NULL) {
+#if NPF > 0
+ if (m->m_flags & M_PKTHDR)
+ m_resethdr(m);
+#endif
ml_enqueue(&ml, m);
- else
+ } else
m_freem(m);
}
