[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: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -27,22 +27,18 @@ MODULE_DESCRIPTION("iptables ECN modification module");
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static inline int
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set_ect_ip(struct sk_buff **pskb, const struct ipt_ECN_info *einfo)
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{
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if (((*pskb)->nh.iph->tos & IPT_ECN_IP_MASK)
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!= (einfo->ip_ect & IPT_ECN_IP_MASK)) {
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u_int16_t diffs[2];
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struct iphdr *iph = (*pskb)->nh.iph;
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u_int16_t oldtos;
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if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
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if (!skb_make_writable(pskb, sizeof(struct iphdr)))
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return 0;
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diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;
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(*pskb)->nh.iph->tos &= ~IPT_ECN_IP_MASK;
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(*pskb)->nh.iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
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diffs[1] = htons((*pskb)->nh.iph->tos);
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(*pskb)->nh.iph->check
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= csum_fold(csum_partial((char *)diffs,
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sizeof(diffs),
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(*pskb)->nh.iph->check
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^0xFFFF));
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iph = (*pskb)->nh.iph;
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oldtos = iph->tos;
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iph->tos &= ~IPT_ECN_IP_MASK;
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iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
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iph->check = nf_csum_update(oldtos ^ 0xFFFF, iph->tos,
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iph->check);
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}
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return 1;
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}
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@ -30,23 +30,17 @@ target(struct sk_buff **pskb,
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void *userinfo)
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{
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const struct ipt_tos_target_info *tosinfo = targinfo;
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struct iphdr *iph = (*pskb)->nh.iph;
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u_int16_t oldtos;
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if (((*pskb)->nh.iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {
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u_int16_t diffs[2];
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if ((iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) {
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if (!skb_make_writable(pskb, sizeof(struct iphdr)))
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return NF_DROP;
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diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;
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(*pskb)->nh.iph->tos
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= ((*pskb)->nh.iph->tos & IPTOS_PREC_MASK)
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diffs[1] = htons((*pskb)->nh.iph->tos);
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(*pskb)->nh.iph->check
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= csum_fold(csum_partial((char *)diffs,
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sizeof(diffs),
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(*pskb)->nh.iph->check
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^0xFFFF));
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iph = (*pskb)->nh.iph;
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oldtos = iph->tos;
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iph->tos = (iph->tos & IPTOS_PREC_MASK) | tosinfo->tos;
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iph->check = nf_csum_update(oldtos ^ 0xFFFF, iph->tos,
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iph->check);
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}
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return IPT_CONTINUE;
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}
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@ -27,7 +27,6 @@ ipt_ttl_target(struct sk_buff **pskb,
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{
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struct iphdr *iph;
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const struct ipt_TTL_info *info = targinfo;
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u_int16_t diffs[2];
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int new_ttl;
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if (!skb_make_writable(pskb, (*pskb)->len))
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@ -55,12 +54,10 @@ ipt_ttl_target(struct sk_buff **pskb,
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}
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if (new_ttl != iph->ttl) {
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diffs[0] = htons(((unsigned)iph->ttl) << 8) ^ 0xFFFF;
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iph->check = nf_csum_update((iph->ttl << 8) ^ 0xFFFF,
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new_ttl << 8,
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iph->check);
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iph->ttl = new_ttl;
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diffs[1] = htons(((unsigned)iph->ttl) << 8);
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iph->check = csum_fold(csum_partial((char *)diffs,
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sizeof(diffs),
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iph->check^0xFFFF));
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}
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return IPT_CONTINUE;
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