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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_queue.h>
#include <net/ip6_checksum.h>
#ifdef CONFIG_INET
__sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u8 protocol)
{
const struct iphdr *iph = ip_hdr(skb);
__sum16 csum = 0;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
break;
if ((protocol != IPPROTO_TCP && protocol != IPPROTO_UDP &&
!csum_fold(skb->csum)) ||
!csum_tcpudp_magic(iph->saddr, iph->daddr,
skb->len - dataoff, protocol,
skb->csum)) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
fallthrough;
case CHECKSUM_NONE:
if (protocol != IPPROTO_TCP && protocol != IPPROTO_UDP)
skb->csum = 0;
else
skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
skb->len - dataoff,
protocol, 0);
csum = __skb_checksum_complete(skb);
}
return csum;
}
EXPORT_SYMBOL(nf_ip_checksum);
#endif
static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, unsigned int len,
u8 protocol)
{
const struct iphdr *iph = ip_hdr(skb);
__sum16 csum = 0;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
if (len == skb->len - dataoff)
return nf_ip_checksum(skb, hook, dataoff, protocol);
fallthrough;
case CHECKSUM_NONE:
skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr, protocol,
skb->len - dataoff, 0);
skb->ip_summed = CHECKSUM_NONE;
return __skb_checksum_complete_head(skb, dataoff + len);
}
return csum;
}
__sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u8 protocol)
{
const struct ipv6hdr *ip6h = ipv6_hdr(skb);
__sum16 csum = 0;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
break;
if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
skb->len - dataoff, protocol,
csum_sub(skb->csum,
skb_checksum(skb, 0,
dataoff, 0)))) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
fallthrough;
case CHECKSUM_NONE:
skb->csum = ~csum_unfold(
csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
skb->len - dataoff,
protocol,
csum_sub(0,
skb_checksum(skb, 0,
dataoff, 0))));
csum = __skb_checksum_complete(skb);
}
return csum;
}
EXPORT_SYMBOL(nf_ip6_checksum);
static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, unsigned int len,
u8 protocol)
{
const struct ipv6hdr *ip6h = ipv6_hdr(skb);
__wsum hsum;
__sum16 csum = 0;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
if (len == skb->len - dataoff)
return nf_ip6_checksum(skb, hook, dataoff, protocol);
fallthrough;
case CHECKSUM_NONE:
hsum = skb_checksum(skb, 0, dataoff, 0);
skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
&ip6h->daddr,
skb->len - dataoff,
protocol,
csum_sub(0, hsum)));
skb->ip_summed = CHECKSUM_NONE;
return __skb_checksum_complete_head(skb, dataoff + len);
}
return csum;
};
__sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u8 protocol,
unsigned short family)
{
__sum16 csum = 0;
switch (family) {
case AF_INET:
csum = nf_ip_checksum(skb, hook, dataoff, protocol);
break;
case AF_INET6:
csum = nf_ip6_checksum(skb, hook, dataoff, protocol);
break;
}
return csum;
}
EXPORT_SYMBOL_GPL(nf_checksum);
__sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, unsigned int len,
u8 protocol, unsigned short family)
{
__sum16 csum = 0;
switch (family) {
case AF_INET:
csum = nf_ip_checksum_partial(skb, hook, dataoff, len,
protocol);
break;
case AF_INET6:
csum = nf_ip6_checksum_partial(skb, hook, dataoff, len,
protocol);
break;
}
return csum;
}
EXPORT_SYMBOL_GPL(nf_checksum_partial);
int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
bool strict, unsigned short family)
{
const struct nf_ipv6_ops *v6ops __maybe_unused;
int ret = 0;
switch (family) {
case AF_INET:
ret = nf_ip_route(net, dst, fl, strict);
break;
case AF_INET6:
ret = nf_ip6_route(net, dst, fl, strict);
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(nf_route);
static int nf_ip_reroute(struct sk_buff *skb, const struct nf_queue_entry *entry)
{
#ifdef CONFIG_INET
const struct ip_rt_info *rt_info = nf_queue_entry_reroute(entry);
if (entry->state.hook == NF_INET_LOCAL_OUT) {
const struct iphdr *iph = ip_hdr(skb);
if (!(iph->tos == rt_info->tos &&
skb->mark == rt_info->mark &&
iph->daddr == rt_info->daddr &&
iph->saddr == rt_info->saddr))
return ip_route_me_harder(entry->state.net, skb,
RTN_UNSPEC);
}
#endif
return 0;
}
int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry)
{
const struct nf_ipv6_ops *v6ops;
int ret = 0;
switch (entry->state.pf) {
case AF_INET:
ret = nf_ip_reroute(skb, entry);
break;
case AF_INET6:
v6ops = rcu_dereference(nf_ipv6_ops);
if (v6ops)
ret = v6ops->reroute(skb, entry);
break;
}
return ret;
}
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