Implement TUN[GS]IFHEAD ioctls. Passing a non-zero int to TUNSIFHEAD

tells that tun unit to prepend a four byte address family to packets
queued for tunread() and to expect a four byte address family at the
front of data received by tunwrite().

We queue any protocol received from the interface for tunread(), but
only accept INET, INET6, IPX and NETATALK from tunwrite().  There is
support for Xerox's NS stuff, but AFAICT config(8) doesn't ever
define NS.

1 files changed, 137 insertions, 39 deletions

diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c
index 7ad4d59..06befe4 100644
--- a/sys/net/if_tun.c
+++ b/sys/net/if_tun.c
@@ -16,7 +16,10 @@
  * $FreeBSD$
  */
 
+#include "opt_atalk.h"
 #include "opt_inet.h"
+#include "opt_inet6.h"
+#include "opt_ipx.h"
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -45,11 +48,27 @@
 #include <netinet/in_var.h>
 #endif
 
+#ifdef INET6
+#include <netinet6/in6.h>
+#include <netinet6/in6_var.h>
+#endif
+
 #ifdef NS
+/* This will never be defined by config(8), or for the if_tun module ! */
 #include <netns/ns.h>
 #include <netns/ns_if.h>
 #endif
 
+#ifdef IPX
+#include <netipx/ipx.h>
+#include <netipx/ipx_if.h>
+#endif
+
+#ifdef NETATALK
+#include <netatalk/at.h>
+#include <netatalk/at_var.h>
+#endif
+
 #include <net/bpf.h>
 
 #include <net/if_tunvar.h>
@@ -369,27 +388,41 @@ tunoutput(ifp, m0, dst, rt)
 		}
 	}
 
-	switch(dst->sa_family) {
-#ifdef INET
-	case AF_INET:
-		s = splimp();
-		if (IF_QFULL(&ifp->if_snd)) {
+	if (tp->tun_flags & TUN_IFHEAD) {
+		/* Prepend the address family */
+		M_PREPEND(m0, 4, M_DONTWAIT);
+
+		/* if allocation failed drop packet */
+		if (m0 == NULL){
+			s = splimp();	/* spl on queue manipulation */
 			IF_DROP(&ifp->if_snd);
-			m_freem(m0);
 			splx(s);
-			ifp->if_collisions++;
-			return (ENOBUFS);
-		}
-		ifp->if_obytes += m0->m_pkthdr.len;
-		IF_ENQUEUE(&ifp->if_snd, m0);
-		splx(s);
-		ifp->if_opackets++;
-		break;
+			ifp->if_oerrors++;
+			return ENOBUFS;
+		} else
+			*(u_int32_t *)m0->m_data = htonl(dst->sa_family);
+	} else {
+#ifdef INET
+		if (dst->sa_family != AF_INET)
 #endif
-	default:
+		{
+			m_freem(m0);
+			return EAFNOSUPPORT;
+		}
+	}
+
+	s = splimp();
+	if (IF_QFULL(&ifp->if_snd)) {
+		IF_DROP(&ifp->if_snd);
 		m_freem(m0);
-		return EAFNOSUPPORT;
+		splx(s);
+		ifp->if_collisions++;
+		return ENOBUFS;
 	}
+	ifp->if_obytes += m0->m_pkthdr.len;
+	IF_ENQUEUE(&ifp->if_snd, m0);
+	splx(s);
+	ifp->if_opackets++;
 
 	if (tp->tun_flags & TUN_RWAIT) {
 		tp->tun_flags &= ~TUN_RWAIT;
@@ -418,7 +451,7 @@ tunioctl(dev, cmd, data, flag, p)
 
 	switch (cmd) {
  	case TUNSIFINFO:
- 	        tunp = (struct tuninfo *)data;
+ 		tunp = (struct tuninfo *)data;
 		if (tunp->mtu < IF_MINMTU)
 			return (EINVAL);
  		tp->tun_if.if_mtu = tunp->mtu;
@@ -438,11 +471,22 @@ tunioctl(dev, cmd, data, flag, p)
 		*(int *)data = tundebug;
 		break;
 	case TUNSLMODE:
-		if (*(int *)data)
+		if (*(int *)data) {
 			tp->tun_flags |= TUN_LMODE;
-		else 
+			tp->tun_flags &= ~TUN_IFHEAD;
+		} else
 			tp->tun_flags &= ~TUN_LMODE;
 		break;
+	case TUNSIFHEAD:
+		if (*(int *)data) {
+			tp->tun_flags |= TUN_IFHEAD;
+			tp->tun_flags &= ~TUN_LMODE;
+		} else 
+			tp->tun_flags &= ~TUN_IFHEAD;
+		break;
+	case TUNGIFHEAD:
+		*(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0;
+		break;
 	case TUNSIFMODE:
 		/* deny this if UP */
 		if (tp->tun_if.if_flags & IFF_UP)
@@ -574,7 +618,9 @@ tunwrite(dev, uio, flag)
 	struct tun_softc *tp = dev->si_drv1;
 	struct ifnet	*ifp = &tp->tun_if;
 	struct mbuf	*top, **mp, *m;
-	int		error=0, s, tlen, mlen;
+	int		error=0, s, tlen, mlen, isr;
+	u_int32_t	family;
+	struct ifqueue	*q;
 
 	TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit);
 
@@ -620,38 +666,90 @@ tunwrite(dev, uio, flag)
 	top->m_pkthdr.rcvif = ifp;
 
 	if (ifp->if_bpf) {
-		/*
-		 * We need to prepend the address family as
-		 * a four byte field.  Cons up a dummy header
-		 * to pacify bpf.  This is safe because bpf
-		 * will only read from the mbuf (i.e., it won't
-		 * try to free it or keep a pointer to it).
-		 */
-		struct mbuf m;
-		u_int af = AF_INET;
+		if (tp->tun_flags & TUN_IFHEAD)
+			/*
+			 * Conveniently, we already have a 4-byte address
+			 * family prepended to our packet !
+			 */
+			bpf_mtap(ifp, top);
+		else {
+			/*
+			 * We need to prepend the address family as
+			 * a four byte field.  Cons up a dummy header
+			 * to pacify bpf.  This is safe because bpf
+			 * will only read from the mbuf (i.e., it won't
+			 * try to free it or keep a pointer to it).
+			 */
+			struct mbuf m;
+			u_int af = AF_INET;
+
+			m.m_next = top;
+			m.m_len = 4;
+			m.m_data = (char *)&af;
+
+			bpf_mtap(ifp, &m);
+		}
+	}
 
-		m.m_next = top;
-		m.m_len = 4;
-		m.m_data = (char *)&af;
+	if (tp->tun_flags & TUN_IFHEAD) {
+		if (top->m_len < sizeof(family) &&
+		    (top = m_pullup(top, sizeof(family))) == NULL)
+				return ENOBUFS;
+		family = ntohl(*mtod(top, u_int32_t *));
+		m_adj(top, sizeof(family));
+	} else
+		family = AF_INET;
 
-		bpf_mtap(ifp, &m);
+	switch (family) {
+#ifdef INET
+	case AF_INET:
+		q = &ipintrq;
+		isr = NETISR_IP;
+		break;
+#endif
+#ifdef INET6
+	case AF_INET6:
+		q = &ip6intrq;
+		isr = NETISR_IPV6;
+		break;
+#endif
+#ifdef NS
+	case AF_NS:
+		q = &nsintrq;
+		isr = NETISR_NS;
+		break;
+#endif
+#ifdef IPX
+	case AF_IPX:
+		q = &ipxintrq;
+		isr = NETISR_IPX;
+		break;
+#endif
+#ifdef NETATALK
+	case AF_APPLETALK:
+		q = &atintrq2;
+		isr = NETISR_ATALK;
+		break;
+#endif
+	default:
+		m_freem(top);
+		return EAFNOSUPPORT;
 	}
 
-#ifdef INET
 	s = splimp();
-	if (IF_QFULL (&ipintrq)) {
-		IF_DROP(&ipintrq);
+	if (IF_QFULL (q)) {
+		IF_DROP(q);
 		splx(s);
 		ifp->if_collisions++;
 		m_freem(top);
 		return ENOBUFS;
 	}
-	IF_ENQUEUE(&ipintrq, top);
+	IF_ENQUEUE(q, top);
 	splx(s);
 	ifp->if_ibytes += tlen;
 	ifp->if_ipackets++;
-	schednetisr(NETISR_IP);
-#endif
+	schednetisr(isr);
+
 	return error;
 }