Commit da878c8e authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: replace open coded checksum updates 



Replace open coded checksum update by nf_csum_update calls and clean up
the surrounding code a bit.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1158ba27

net/ipv4/netfilter/ipt_ECN.c

+9 −13
Original line number Diff line number Diff line
@@ -27,22 +27,18 @@ MODULE_DESCRIPTION("iptables ECN modification module"); 
static inline int

set_ect_ip(struct sk_buff **pskb, const struct ipt_ECN_info *einfo)

{

	if (((*pskb)->nh.iph->tos & IPT_ECN_IP_MASK)

	    != (einfo->ip_ect & IPT_ECN_IP_MASK)) {

		u_int16_t diffs[2];

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

	u_int16_t oldtos;



	if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) {

		if (!skb_make_writable(pskb, sizeof(struct iphdr)))

			return 0;



		diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;

		(*pskb)->nh.iph->tos &= ~IPT_ECN_IP_MASK;

		(*pskb)->nh.iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);

		diffs[1] = htons((*pskb)->nh.iph->tos);

		(*pskb)->nh.iph->check

			= csum_fold(csum_partial((char *)diffs,

						 sizeof(diffs),

						 (*pskb)->nh.iph->check

						 ^0xFFFF));

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

		oldtos = iph->tos;

		iph->tos &= ~IPT_ECN_IP_MASK;

		iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);

		iph->check = nf_csum_update(oldtos ^ 0xFFFF, iph->tos,

					    iph->check);

	} 

	return 1;

}

net/ipv4/netfilter/ipt_TOS.c

+8 −14
Original line number Diff line number Diff line
@@ -30,23 +30,17 @@ target(struct sk_buff **pskb, 
       void *userinfo)

{

	const struct ipt_tos_target_info *tosinfo = targinfo;

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

	u_int16_t oldtos;



	if (((*pskb)->nh.iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {

		u_int16_t diffs[2];



	if ((iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {

		if (!skb_make_writable(pskb, sizeof(struct iphdr)))

			return NF_DROP;



		diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;

		(*pskb)->nh.iph->tos

			= ((*pskb)->nh.iph->tos & IPTOS_PREC_MASK)

			| tosinfo->tos;

		diffs[1] = htons((*pskb)->nh.iph->tos);

		(*pskb)->nh.iph->check

			= csum_fold(csum_partial((char *)diffs,

						 sizeof(diffs),

						 (*pskb)->nh.iph->check

						 ^0xFFFF));

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

		oldtos = iph->tos;

		iph->tos = (iph->tos & IPTOS_PREC_MASK) | tosinfo->tos;

		iph->check = nf_csum_update(oldtos ^ 0xFFFF, iph->tos,

					    iph->check);

	}

	return IPT_CONTINUE;

}

net/ipv4/netfilter/ipt_TTL.c

+3 −6
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ ipt_ttl_target(struct sk_buff **pskb, 
{

	struct iphdr *iph;

	const struct ipt_TTL_info *info = targinfo;

	u_int16_t diffs[2];

	int new_ttl;



	if (!skb_make_writable(pskb, (*pskb)->len))
@@ -55,12 +54,10 @@ ipt_ttl_target(struct sk_buff **pskb, 
	}



	if (new_ttl != iph->ttl) {

		diffs[0] = htons(((unsigned)iph->ttl) << 8) ^ 0xFFFF;

		iph->check = nf_csum_update((iph->ttl << 8) ^ 0xFFFF,

					    new_ttl << 8,

					    iph->check);

		iph->ttl = new_ttl;

		diffs[1] = htons(((unsigned)iph->ttl) << 8);

		iph->check = csum_fold(csum_partial((char *)diffs,

						    sizeof(diffs),

						    iph->check^0xFFFF));

	}



	return IPT_CONTINUE;

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