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Date:      Thu, 24 Dec 2015 16:18:52 -0500
From:      "George Neville-Neil" <gnn@freebsd.org>
To:        "Cy Schubert" <Cy.Schubert@komquats.com>
Cc:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   Re: svn commit: r290383 - in head/sys: net netinet
Message-ID:  <98F16C2B-3904-438D-912B-85C17ACFBDEA@freebsd.org>
In-Reply-To: <201512201802.tBKI2jpx051586@slippy.cwsent.com>
References:  <201512201802.tBKI2jpx051586@slippy.cwsent.com>

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On 20 Dec 2015, at 13:02, Cy Schubert wrote:

> Cy Schubert writes:
>> In message <201511050726.tA57QXlu074213@repo.freebsd.org>, "George V.
>> Neville-N
>> eil" writes:
>>> Author: gnn
>>> Date: Thu Nov  5 07:26:32 2015
>>> New Revision: 290383
>>> URL: https://svnweb.freebsd.org/changeset/base/290383
>>>
>>> Log:
>>> 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)
>>>
>>> Modified:
>>> head/sys/net/if_arcsubr.c
>>> head/sys/net/if_ethersubr.c
>>> head/sys/net/if_fddisubr.c
>>> head/sys/net/if_fwsubr.c
>>> head/sys/net/if_iso88025subr.c
>>> head/sys/netinet/in_var.h
>>> head/sys/netinet/ip_fastfwd.c
>>> head/sys/netinet/ip_input.c
>>>
>>> Modified: head/sys/net/if_arcsubr.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/net/if_arcsubr.c	Thu Nov  5 04:16:03 2015	(r29038
>> 2)
>>> +++ head/sys/net/if_arcsubr.c	Thu Nov  5 07:26:32 2015	(r29038
>> 3)
>>> @@ -550,15 +550,11 @@ arc_input(struct ifnet *ifp, struct mbuf
>>> #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;
>>>
>>>
>>> Modified: head/sys/net/if_ethersubr.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/net/if_ethersubr.c	Thu Nov  5 04:16:03 2015	(r29038
>>> 2)
>>> +++ head/sys/net/if_ethersubr.c	Thu Nov  5 07:26:32 2015	(r29038
>>> 3)
>>> @@ -722,8 +722,6 @@ ether_demux(struct ifnet *ifp, struct mb
>>> 	switch (ether_type) {
>>> #ifdef INET
>>> 	case ETHERTYPE_IP:
>>> -		if ((m = ip_fastforward(m)) == NULL)
>>> -			return;
>>> 		isr = NETISR_IP;
>>> 		break;
>>>
>>>
>>> Modified: head/sys/net/if_fddisubr.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/net/if_fddisubr.c	Thu Nov  5 04:16:03 2015	(r29038
>>> 2)
>>> +++ head/sys/net/if_fddisubr.c	Thu Nov  5 07:26:32 2015	(r29038
>>> 3)
>>> @@ -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;
>>>
>>>
>>> Modified: head/sys/net/if_fwsubr.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/net/if_fwsubr.c	Thu Nov  5 04:16:03 2015	(r29038
>> 2)
>>> +++ head/sys/net/if_fwsubr.c	Thu Nov  5 07:26:32 2015	(r29038
>> 3)
>>> @@ -605,8 +605,6 @@ firewire_input(struct ifnet *ifp, struct
>>> 	switch (type) {
>>> #ifdef INET
>>> 	case ETHERTYPE_IP:
>>> -		if ((m = ip_fastforward(m)) == NULL)
>>> -			return;
>>> 		isr = NETISR_IP;
>>> 		break;
>>>
>>>
>>> Modified: head/sys/net/if_iso88025subr.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/net/if_iso88025subr.c	Thu Nov  5 04:16:03 2015	(r29038
>>> 2)
>>> +++ head/sys/net/if_iso88025subr.c	Thu Nov  5 07:26:32 2015	(r29038
>>> 3)
>>> @@ -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;
>>>
>>>
>>> Modified: head/sys/netinet/in_var.h
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/netinet/in_var.h	Thu Nov  5 04:16:03 2015	(r29038
>> 2)
>>> +++ head/sys/netinet/in_var.h	Thu Nov  5 07:26:32 2015	(r29038
>> 3)
>>> @@ -380,7 +380,7 @@ int	in_scrubprefix(struct in_ifaddr *, u
>>> 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 *);
>>>
>>>
>>> Modified: head/sys/netinet/ip_fastfwd.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/netinet/ip_fastfwd.c	Thu Nov  5 04:16:03 2015	(r29038
>>> 2)
>>> +++ head/sys/netinet/ip_fastfwd.c	Thu Nov  5 07:26:32 2015	(r29038
>>> 3)
>>> @@ -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
>>> * 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;
>>>
>>> Modified: head/sys/netinet/ip_input.c
>>> ===========================================================================
>> ==
>>> =
>>> --- head/sys/netinet/ip_input.c	Thu Nov  5 04:16:03 2015	(r29038
>>> 2)
>>> +++ head/sys/netinet/ip_input.c	Thu Nov  5 07:26:32 2015	(r29038
>>> 3)
>>> @@ -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 */
>>>
>>> 	/*
>>>
>>>
>>
>> Hi George,
>>
>> Sorry for the lateness of this reply, I finally got some time off for
>> Christmas and have time to myself to boot.
>>
>> This breaks ipfilter's ipnat. I want to let you know before anyone 
>> MFCs
>> this.
>
> A fix to ipfilter has been committed to head and will be MFCed in a 
> week.
>

Let me know when that's done.

Thanks!

Best,
George



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