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Commit 4cf411de authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: Get rid of HW checksum invalidation 



Update hardware checksums incrementally to avoid breaking GSO.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 84fa7933

include/linux/netfilter.h

+6 −0
Original line number Diff line number Diff line
@@ -282,6 +282,12 @@ extern void nf_invalidate_cache(int pf); 
   Returns true or false. */

extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);



extern u_int16_t nf_csum_update(u_int32_t oldval, u_int32_t newval,

				u_int32_t csum);

extern u_int16_t nf_proto_csum_update(struct sk_buff *skb,

				      u_int32_t oldval, u_int32_t newval,

				      u_int16_t csum, int pseudohdr);



struct nf_afinfo {

	unsigned short	family;

	unsigned int	(*checksum)(struct sk_buff *skb, unsigned int hook,

include/linux/netfilter_ipv4/ip_nat.h

+0 −4
Original line number Diff line number Diff line
@@ -72,10 +72,6 @@ extern unsigned int ip_nat_setup_info(struct ip_conntrack *conntrack, 
extern int ip_nat_used_tuple(const struct ip_conntrack_tuple *tuple,

			     const struct ip_conntrack *ignored_conntrack);



/* Calculate relative checksum. */

extern u_int16_t ip_nat_cheat_check(u_int32_t oldvalinv,

				    u_int32_t newval,

				    u_int16_t oldcheck);

#else  /* !__KERNEL__: iptables wants this to compile. */

#define ip_nat_multi_range ip_nat_multi_range_compat

#endif /*__KERNEL__*/

include/linux/netfilter_ipv4/ip_nat_core.h

+4 −4
Original line number Diff line number Diff line
@@ -11,8 +11,8 @@ extern unsigned int ip_nat_packet(struct ip_conntrack *ct, 
			       unsigned int hooknum,

			       struct sk_buff **pskb);



extern int ip_nat_icmp_reply_translation(struct sk_buff **pskb,

					 struct ip_conntrack *ct,

					 enum ip_nat_manip_type manip,

					 enum ip_conntrack_dir dir);

extern int ip_nat_icmp_reply_translation(struct ip_conntrack *ct,

					 enum ip_conntrack_info ctinfo,

					 unsigned int hooknum,

					 struct sk_buff **pskb);

#endif /* _IP_NAT_CORE_H */

net/ipv4/netfilter/ip_nat_core.c

+20 −32
Original line number Diff line number Diff line
@@ -101,18 +101,6 @@ static void ip_nat_cleanup_conntrack(struct ip_conntrack *conn) 
	write_unlock_bh(&ip_nat_lock);

}



/* We do checksum mangling, so if they were wrong before they're still

 * wrong.  Also works for incomplete packets (eg. ICMP dest

 * unreachables.) */

u_int16_t

ip_nat_cheat_check(u_int32_t oldvalinv, u_int32_t newval, u_int16_t oldcheck)

{

	u_int32_t diffs[] = { oldvalinv, newval };

	return csum_fold(csum_partial((char *)diffs, sizeof(diffs),

				      oldcheck^0xFFFF));

}

EXPORT_SYMBOL(ip_nat_cheat_check);



/* Is this tuple already taken? (not by us) */

int

ip_nat_used_tuple(const struct ip_conntrack_tuple *tuple,
@@ -378,11 +366,11 @@ manip_pkt(u_int16_t proto, 
	iph = (void *)(*pskb)->data + iphdroff;



	if (maniptype == IP_NAT_MANIP_SRC) {

		iph->check = ip_nat_cheat_check(~iph->saddr, target->src.ip,

		iph->check = nf_csum_update(~iph->saddr, target->src.ip,

					    iph->check);

		iph->saddr = target->src.ip;

	} else {

		iph->check = ip_nat_cheat_check(~iph->daddr, target->dst.ip,

		iph->check = nf_csum_update(~iph->daddr, target->dst.ip,

					    iph->check);

		iph->daddr = target->dst.ip;

	}
@@ -423,10 +411,10 @@ unsigned int ip_nat_packet(struct ip_conntrack *ct, 
EXPORT_SYMBOL_GPL(ip_nat_packet);



/* Dir is direction ICMP is coming from (opposite to packet it contains) */

int ip_nat_icmp_reply_translation(struct sk_buff **pskb,

				  struct ip_conntrack *ct,

				  enum ip_nat_manip_type manip,

				  enum ip_conntrack_dir dir)

int ip_nat_icmp_reply_translation(struct ip_conntrack *ct,

				  enum ip_conntrack_info ctinfo,

				  unsigned int hooknum,

				  struct sk_buff **pskb)

{

	struct {

		struct icmphdr icmp;
@@ -434,7 +422,9 @@ int ip_nat_icmp_reply_translation(struct sk_buff **pskb, 
	} *inside;

	struct ip_conntrack_tuple inner, target;

	int hdrlen = (*pskb)->nh.iph->ihl * 4;

	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

	unsigned long statusbit;

	enum ip_nat_manip_type manip = HOOK2MANIP(hooknum);



	if (!skb_make_writable(pskb, hdrlen + sizeof(*inside)))

		return 0;
@@ -443,12 +433,8 @@ int ip_nat_icmp_reply_translation(struct sk_buff **pskb, 


	/* We're actually going to mangle it beyond trivial checksum

	   adjustment, so make sure the current checksum is correct. */

	if ((*pskb)->ip_summed != CHECKSUM_UNNECESSARY) {

		hdrlen = (*pskb)->nh.iph->ihl * 4;

		if ((u16)csum_fold(skb_checksum(*pskb, hdrlen,

						(*pskb)->len - hdrlen, 0)))

	if (nf_ip_checksum(*pskb, hooknum, hdrlen, 0))

		return 0;

	}



	/* Must be RELATED */

	IP_NF_ASSERT((*pskb)->nfctinfo == IP_CT_RELATED ||
@@ -487,12 +473,14 @@ int ip_nat_icmp_reply_translation(struct sk_buff **pskb, 
		       !manip))

		return 0;



	if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {

		/* Reloading "inside" here since manip_pkt inner. */

		inside = (void *)(*pskb)->data + (*pskb)->nh.iph->ihl*4;

		inside->icmp.checksum = 0;

		inside->icmp.checksum = csum_fold(skb_checksum(*pskb, hdrlen,

							       (*pskb)->len - hdrlen,

							       0));

	}



	/* Change outer to look the reply to an incoming packet

	 * (proto 0 means don't invert per-proto part). */

net/ipv4/netfilter/ip_nat_helper.c

+41 −18
Original line number Diff line number Diff line
@@ -165,7 +165,7 @@ ip_nat_mangle_tcp_packet(struct sk_buff **pskb, 
{

	struct iphdr *iph;

	struct tcphdr *tcph;

	int datalen;

	int oldlen, datalen;



	if (!skb_make_writable(pskb, (*pskb)->len))

		return 0;
@@ -180,13 +180,22 @@ ip_nat_mangle_tcp_packet(struct sk_buff **pskb, 
	iph = (*pskb)->nh.iph;

	tcph = (void *)iph + iph->ihl*4;



	oldlen = (*pskb)->len - iph->ihl*4;

	mangle_contents(*pskb, iph->ihl*4 + tcph->doff*4,

			match_offset, match_len, rep_buffer, rep_len);



	datalen = (*pskb)->len - iph->ihl*4;

	if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {

		tcph->check = 0;

	tcph->check = tcp_v4_check(tcph, datalen, iph->saddr, iph->daddr,

				   csum_partial((char *)tcph, datalen, 0));

		tcph->check = tcp_v4_check(tcph, datalen,

					   iph->saddr, iph->daddr,

					   csum_partial((char *)tcph,

					   		datalen, 0));

	} else

		tcph->check = nf_proto_csum_update(*pskb,

						   htons(oldlen) ^ 0xFFFF,

						   htons(datalen),

						   tcph->check, 1);



	if (rep_len != match_len) {

		set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
@@ -221,6 +230,7 @@ ip_nat_mangle_udp_packet(struct sk_buff **pskb, 
{

	struct iphdr *iph;

	struct udphdr *udph;

	int datalen, oldlen;



	/* UDP helpers might accidentally mangle the wrong packet */

	iph = (*pskb)->nh.iph;
@@ -238,22 +248,32 @@ ip_nat_mangle_udp_packet(struct sk_buff **pskb, 


	iph = (*pskb)->nh.iph;

	udph = (void *)iph + iph->ihl*4;



	oldlen = (*pskb)->len - iph->ihl*4;

	mangle_contents(*pskb, iph->ihl*4 + sizeof(*udph),

			match_offset, match_len, rep_buffer, rep_len);



	/* update the length of the UDP packet */

	udph->len = htons((*pskb)->len - iph->ihl*4);

	datalen = (*pskb)->len - iph->ihl*4;

	udph->len = htons(datalen);



	/* fix udp checksum if udp checksum was previously calculated */

	if (udph->check) {

		int datalen = (*pskb)->len - iph->ihl * 4;

	if (!udph->check && (*pskb)->ip_summed != CHECKSUM_PARTIAL)

		return 1;



	if ((*pskb)->ip_summed != CHECKSUM_PARTIAL) {

		udph->check = 0;

		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,

		                                datalen, IPPROTO_UDP,

		                                csum_partial((char *)udph,

		                                             datalen, 0));

	}



		if (!udph->check)

			udph->check = -1;

	} else

		udph->check = nf_proto_csum_update(*pskb,

						   htons(oldlen) ^ 0xFFFF,

						   htons(datalen),

						   udph->check, 1);

	return 1;

}

EXPORT_SYMBOL(ip_nat_mangle_udp_packet);
@@ -293,11 +313,14 @@ sack_adjust(struct sk_buff *skb, 
			ntohl(sack->start_seq), new_start_seq,

			ntohl(sack->end_seq), new_end_seq);



		tcph->check = 

			ip_nat_cheat_check(~sack->start_seq, new_start_seq,

					   ip_nat_cheat_check(~sack->end_seq, 

		tcph->check = nf_proto_csum_update(skb,

						   ~sack->start_seq,

						   new_start_seq,

						   tcph->check, 0);

		tcph->check = nf_proto_csum_update(skb,

						   ~sack->end_seq,

						   new_end_seq,

							      tcph->check));

						   tcph->check, 0);

		sack->start_seq = new_start_seq;

		sack->end_seq = new_end_seq;

		sackoff += sizeof(*sack);
@@ -381,10 +404,10 @@ ip_nat_seq_adjust(struct sk_buff **pskb, 
		newack = ntohl(tcph->ack_seq) - other_way->offset_before;

	newack = htonl(newack);



	tcph->check = ip_nat_cheat_check(~tcph->seq, newseq,

					 ip_nat_cheat_check(~tcph->ack_seq, 

					 		    newack, 

							    tcph->check));

	tcph->check = nf_proto_csum_update(*pskb, ~tcph->seq, newseq,

					   tcph->check, 0);

	tcph->check = nf_proto_csum_update(*pskb, ~tcph->ack_seq, newack,

					   tcph->check, 0);



	DEBUGP("Adjusting sequence number from %u->%u, ack from %u->%u\n",

		ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq),