// 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;}