[RFC PATCH net-next v2 3/8] netfilter: Allow calling into nat helper without skb_dst.
From: Jarno Rajahalme <hidden>
Date: 2015-11-07 00:06:03
Also in:
netfilter-devel
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
NAT checksum recalculation code assumes existence of skb_dst, which
becomes a problem for a later patch in the series ("openvswitch:
Interface with NAT."). Simplify this by removing the check on
skb_dst, as the checksum will be dealt with later in the stack.
Suggested-by: Pravin Shelar <redacted>
Signed-off-by: Jarno Rajahalme <redacted>
---
net/ipv4/netfilter/nf_nat_l3proto_ipv4.c | 29 ++++++++---------------------
net/ipv6/netfilter/nf_nat_l3proto_ipv6.c | 29 ++++++++---------------------
2 files changed, 16 insertions(+), 42 deletions(-)
diff --git a/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c b/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
index 5075b7e..f8aad03 100644
--- a/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_nat_l3proto_ipv4.c@@ -127,28 +127,15 @@ static void nf_nat_ipv4_csum_recalc(struct sk_buff *skb, u8 proto, void *data, __sum16 *check, int datalen, int oldlen) { - const struct iphdr *iph = ip_hdr(skb); - struct rtable *rt = skb_rtable(skb); - if (skb->ip_summed != CHECKSUM_PARTIAL) { - if (!(rt->rt_flags & RTCF_LOCAL) && - (!skb->dev || skb->dev->features & NETIF_F_V4_CSUM)) { - skb->ip_summed = CHECKSUM_PARTIAL; - skb->csum_start = skb_headroom(skb) + - skb_network_offset(skb) + - ip_hdrlen(skb); - skb->csum_offset = (void *)check - data; - *check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, - datalen, proto, 0); - } else { - *check = 0; - *check = csum_tcpudp_magic(iph->saddr, iph->daddr, - datalen, proto, - csum_partial(data, datalen, - 0)); - if (proto == IPPROTO_UDP && !*check) - *check = CSUM_MANGLED_0; - } + const struct iphdr *iph = ip_hdr(skb); + + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_headroom(skb) + skb_network_offset(skb) + + ip_hdrlen(skb); + skb->csum_offset = (void *)check - data; + *check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen, + proto, 0); } else inet_proto_csum_replace2(check, skb, htons(oldlen), htons(datalen), true);
diff --git a/net/ipv6/netfilter/nf_nat_l3proto_ipv6.c b/net/ipv6/netfilter/nf_nat_l3proto_ipv6.c
index 238e70c..e0be97e 100644
--- a/net/ipv6/netfilter/nf_nat_l3proto_ipv6.c
+++ b/net/ipv6/netfilter/nf_nat_l3proto_ipv6.c@@ -131,28 +131,15 @@ static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb, u8 proto, void *data, __sum16 *check, int datalen, int oldlen) { - const struct ipv6hdr *ipv6h = ipv6_hdr(skb); - struct rt6_info *rt = (struct rt6_info *)skb_dst(skb); - if (skb->ip_summed != CHECKSUM_PARTIAL) { - if (!(rt->rt6i_flags & RTF_LOCAL) && - (!skb->dev || skb->dev->features & NETIF_F_V6_CSUM)) { - skb->ip_summed = CHECKSUM_PARTIAL; - skb->csum_start = skb_headroom(skb) + - skb_network_offset(skb) + - (data - (void *)skb->data); - skb->csum_offset = (void *)check - data; - *check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, - datalen, proto, 0); - } else { - *check = 0; - *check = csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, - datalen, proto, - csum_partial(data, datalen, - 0)); - if (proto == IPPROTO_UDP && !*check) - *check = CSUM_MANGLED_0; - } + const struct ipv6hdr *ipv6h = ipv6_hdr(skb); + + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_headroom(skb) + skb_network_offset(skb) + + (data - (void *)skb->data); + skb->csum_offset = (void *)check - data; + *check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, + datalen, proto, 0); } else inet_proto_csum_replace2(check, skb, htons(oldlen), htons(datalen), true);
--
2.1.4
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