From da878c8e5aae3eeceeee7af8d52633d7bc125edf Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 22 Aug 2006 00:33:09 -0700 Subject: [PATCH] [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 Signed-off-by: David S. Miller --- net/ipv4/netfilter/ipt_ECN.c | 22 +++++++++------------- net/ipv4/netfilter/ipt_TOS.c | 22 ++++++++-------------- net/ipv4/netfilter/ipt_TTL.c | 9 +++------ 3 files changed, 20 insertions(+), 33 deletions(-) diff --git a/net/ipv4/netfilter/ipt_ECN.c b/net/ipv4/netfilter/ipt_ECN.c index 35916c74fe..7e30e6d2b5 100644 --- a/net/ipv4/netfilter/ipt_ECN.c +++ b/net/ipv4/netfilter/ipt_ECN.c @@ -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; } diff --git a/net/ipv4/netfilter/ipt_TOS.c b/net/ipv4/netfilter/ipt_TOS.c index 1c7a5ca399..52e9d705d4 100644 --- a/net/ipv4/netfilter/ipt_TOS.c +++ b/net/ipv4/netfilter/ipt_TOS.c @@ -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; } diff --git a/net/ipv4/netfilter/ipt_TTL.c b/net/ipv4/netfilter/ipt_TTL.c index f48892ae0b..2afb2a8aa8 100644 --- a/net/ipv4/netfilter/ipt_TTL.c +++ b/net/ipv4/netfilter/ipt_TTL.c @@ -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; -- 2.39.5