Replace the fastforward path with tryforward which does not require a

sysctl and will always be on. The former split between default and
fast forwarding is removed by this commit while preserving the ability
to use all network stack features.

Differential Revision:	https://reviews.freebsd.org/D4042
Reviewed by:	ae, melifaro, olivier, rwatson
MFC after:	1 month
Sponsored by:	Rubicon Communications (Netgate)

8 files changed, 18 insertions, 125 deletions

diff --git a/sys/net/if_arcsubr.c b/sys/net/if_arcsubr.c
index d59c4a0..4944e97 100644
--- a/sys/net/if_arcsubr.c
+++ b/sys/net/if_arcsubr.c
@@ -550,15 +550,11 @@ arc_input(struct ifnet *ifp, struct mbuf *m)
 #ifdef INET
 	case ARCTYPE_IP:
 		m_adj(m, ARC_HDRNEWLEN);
-		if ((m = ip_fastforward(m)) == NULL)
-			return;
 		isr = NETISR_IP;
 		break;
 
 	case ARCTYPE_IP_OLD:
 		m_adj(m, ARC_HDRLEN);
-		if ((m = ip_fastforward(m)) == NULL)
-			return;
 		isr = NETISR_IP;
 		break;
 
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 7bb3d99..71e28ea 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -722,8 +722,6 @@ ether_demux(struct ifnet *ifp, struct mbuf *m)
 	switch (ether_type) {
 #ifdef INET
 	case ETHERTYPE_IP:
-		if ((m = ip_fastforward(m)) == NULL)
-			return;
 		isr = NETISR_IP;
 		break;
 
diff --git a/sys/net/if_fddisubr.c b/sys/net/if_fddisubr.c
index 4a09fcd..81b65a63 100644
--- a/sys/net/if_fddisubr.c
+++ b/sys/net/if_fddisubr.c
@@ -429,8 +429,6 @@ fddi_input(ifp, m)
 		switch (type) {
 #ifdef INET
 		case ETHERTYPE_IP:
-			if ((m = ip_fastforward(m)) == NULL)
-				return;
 			isr = NETISR_IP;
 			break;
 
diff --git a/sys/net/if_fwsubr.c b/sys/net/if_fwsubr.c
index f8ec120..626b1cb 100644
--- a/sys/net/if_fwsubr.c
+++ b/sys/net/if_fwsubr.c
@@ -605,8 +605,6 @@ firewire_input(struct ifnet *ifp, struct mbuf *m, uint16_t src)
 	switch (type) {
 #ifdef INET
 	case ETHERTYPE_IP:
-		if ((m = ip_fastforward(m)) == NULL)
-			return;
 		isr = NETISR_IP;
 		break;
 
diff --git a/sys/net/if_iso88025subr.c b/sys/net/if_iso88025subr.c
index 976e410..7192998 100644
--- a/sys/net/if_iso88025subr.c
+++ b/sys/net/if_iso88025subr.c
@@ -519,8 +519,6 @@ iso88025_input(ifp, m)
 #ifdef INET
 		case ETHERTYPE_IP:
 			th->iso88025_shost[0] &= ~(TR_RII); 
-			if ((m = ip_fastforward(m)) == NULL)
-				return;
 			isr = NETISR_IP;
 			break;
 
diff --git a/sys/netinet/in_var.h b/sys/netinet/in_var.h
index e491ba4..f21ddf4 100644
--- a/sys/netinet/in_var.h
+++ b/sys/netinet/in_var.h
@@ -380,7 +380,7 @@ int	in_scrubprefix(struct in_ifaddr *, u_int);
 void	ip_input(struct mbuf *);
 void	ip_direct_input(struct mbuf *);
 void	in_ifadown(struct ifaddr *ifa, int);
-struct	mbuf	*ip_fastforward(struct mbuf *);
+struct	mbuf	*ip_tryforward(struct mbuf *);
 void	*in_domifattach(struct ifnet *);
 void	in_domifdetach(struct ifnet *, void *);
 
diff --git a/sys/netinet/ip_fastfwd.c b/sys/netinet/ip_fastfwd.c
index 09ca4d7..22eb727 100644
--- a/sys/netinet/ip_fastfwd.c
+++ b/sys/netinet/ip_fastfwd.c
@@ -108,12 +108,6 @@ __FBSDID("$FreeBSD$");
 
 #include <machine/in_cksum.h>
 
-static VNET_DEFINE(int, ipfastforward_active);
-#define	V_ipfastforward_active		VNET(ipfastforward_active)
-
-SYSCTL_INT(_net_inet_ip, OID_AUTO, fastforwarding, CTLFLAG_VNET | CTLFLAG_RW,
-    &VNET_NAME(ipfastforward_active), 0, "Enable fast IP forwarding");
-
 static struct sockaddr_in *
 ip_findroute(struct route *ro, struct in_addr dest, struct mbuf *m)
 {
@@ -158,7 +152,7 @@ ip_findroute(struct route *ro, struct in_addr dest, struct mbuf *m)
  * to ip_input for full processing.
  */
 struct mbuf *
-ip_fastforward(struct mbuf *m)
+ip_tryforward(struct mbuf *m)
 {
 	struct ip *ip;
 	struct mbuf *m0 = NULL;
@@ -166,119 +160,20 @@ ip_fastforward(struct mbuf *m)
 	struct sockaddr_in *dst = NULL;
 	struct ifnet *ifp;
 	struct in_addr odest, dest;
-	uint16_t sum, ip_len, ip_off;
+	uint16_t ip_len, ip_off;
 	int error = 0;
-	int hlen, mtu;
+	int mtu;
 	struct m_tag *fwd_tag = NULL;
 
 	/*
 	 * Are we active and forwarding packets?
 	 */
-	if (!V_ipfastforward_active || !V_ipforwarding)
-		return m;
 
 	M_ASSERTVALID(m);
 	M_ASSERTPKTHDR(m);
 
 	bzero(&ro, sizeof(ro));
 
-	/*
-	 * Step 1: check for packet drop conditions (and sanity checks)
-	 */
-
-	/*
-	 * Is entire packet big enough?
-	 */
-	if (m->m_pkthdr.len < sizeof(struct ip)) {
-		IPSTAT_INC(ips_tooshort);
-		goto drop;
-	}
-
-	/*
-	 * Is first mbuf large enough for ip header and is header present?
-	 */
-	if (m->m_len < sizeof (struct ip) &&
-	   (m = m_pullup(m, sizeof (struct ip))) == NULL) {
-		IPSTAT_INC(ips_toosmall);
-		return NULL;	/* mbuf already free'd */
-	}
-
-	ip = mtod(m, struct ip *);
-
-	/*
-	 * Is it IPv4?
-	 */
-	if (ip->ip_v != IPVERSION) {
-		IPSTAT_INC(ips_badvers);
-		goto drop;
-	}
-
-	/*
-	 * Is IP header length correct and is it in first mbuf?
-	 */
-	hlen = ip->ip_hl << 2;
-	if (hlen < sizeof(struct ip)) {	/* minimum header length */
-		IPSTAT_INC(ips_badhlen);
-		goto drop;
-	}
-	if (hlen > m->m_len) {
-		if ((m = m_pullup(m, hlen)) == NULL) {
-			IPSTAT_INC(ips_badhlen);
-			return NULL;	/* mbuf already free'd */
-		}
-		ip = mtod(m, struct ip *);
-	}
-
-	/*
-	 * Checksum correct?
-	 */
-	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED)
-		sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
-	else {
-		if (hlen == sizeof(struct ip))
-			sum = in_cksum_hdr(ip);
-		else
-			sum = in_cksum(m, hlen);
-	}
-	if (sum) {
-		IPSTAT_INC(ips_badsum);
-		goto drop;
-	}
-
-	/*
-	 * Remember that we have checked the IP header and found it valid.
-	 */
-	m->m_pkthdr.csum_flags |= (CSUM_IP_CHECKED | CSUM_IP_VALID);
-
-	ip_len = ntohs(ip->ip_len);
-
-	/*
-	 * Is IP length longer than packet we have got?
-	 */
-	if (m->m_pkthdr.len < ip_len) {
-		IPSTAT_INC(ips_tooshort);
-		goto drop;
-	}
-
-	/*
-	 * Is packet longer than IP header tells us? If yes, truncate packet.
-	 */
-	if (m->m_pkthdr.len > ip_len) {
-		if (m->m_len == m->m_pkthdr.len) {
-			m->m_len = ip_len;
-			m->m_pkthdr.len = ip_len;
-		} else
-			m_adj(m, ip_len - m->m_pkthdr.len);
-	}
-
-	/*
-	 * Is packet from or to 127/8?
-	 */
-	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
-	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
-		IPSTAT_INC(ips_badaddr);
-		goto drop;
-	}
 
 #ifdef ALTQ
 	/*
@@ -289,12 +184,10 @@ ip_fastforward(struct mbuf *m)
 #endif
 
 	/*
-	 * Step 2: fallback conditions to normal ip_input path processing
-	 */
-
-	/*
 	 * Only IP packets without options
 	 */
+	ip = mtod(m, struct ip *);
+
 	if (ip->ip_hl != (sizeof(struct ip) >> 2)) {
 		if (V_ip_doopts == 1)
 			return m;
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index a406080..4998b14 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -79,6 +79,8 @@ __FBSDID("$FreeBSD$");
 #include <netinet/ip_carp.h>
 #ifdef IPSEC
 #include <netinet/ip_ipsec.h>
+#include <netipsec/ipsec.h>
+#include <netipsec/key.h>
 #endif /* IPSEC */
 #include <netinet/in_rss.h>
 
@@ -500,12 +502,22 @@ tooshort:
 			m_adj(m, ip_len - m->m_pkthdr.len);
 	}
 
+	/* Try to forward the packet, but if we fail continue */
 #ifdef IPSEC
+	/* For now we do not handle IPSEC in tryforward. */
+	if (!key_havesp(IPSEC_DIR_INBOUND) && !key_havesp(IPSEC_DIR_OUTBOUND) &&
+	    (V_ipforwarding == 1))
+		if (ip_tryforward(m) == NULL)
+			return;
 	/*
 	 * Bypass packet filtering for packets previously handled by IPsec.
 	 */
 	if (ip_ipsec_filtertunnel(m))
 		goto passin;
+#else
+	if (V_ipforwarding == 1)
+		if (ip_tryforward(m) == NULL)
+			return;
 #endif /* IPSEC */
 
 	/*