linux/net/netfilter/utils.c

// 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)
{ … }
EXPORT_SYMBOL(…);
#endif

static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
				      unsigned int dataoff, unsigned int len,
				      u8 protocol)
{ … }

__sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
			unsigned int dataoff, u8 protocol)
{ … }
EXPORT_SYMBOL(…);

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)
{ … }
EXPORT_SYMBOL_GPL(…);

__sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
			    unsigned int dataoff, unsigned int len,
			    u8 protocol, unsigned short family)
{ … }
EXPORT_SYMBOL_GPL(…);

int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
	     bool strict, unsigned short family)
{ … }
EXPORT_SYMBOL_GPL(…);

/* Only get and check the lengths, not do any hop-by-hop stuff. */
int nf_ip6_check_hbh_len(struct sk_buff *skb, u32 *plen)
{ … }
EXPORT_SYMBOL_GPL(…);