/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Checksumming functions for IPv6
*
* Authors: Jorge Cwik, <[email protected]>
* Arnt Gulbrandsen, <[email protected]>
* Borrows very liberally from tcp.c and ip.c, see those
* files for more names.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/

/*
* Fixes:
*
* Ralf Baechle : generic ipv6 checksum
* <[email protected]>
*/

#ifndef _CHECKSUM_IPV6_H
#define _CHECKSUM_IPV6_H

#include <asm/types.h>
#include <asm/byteorder.h>
#include <net/ip.h>
#include <asm/checksum.h>
#include <linux/in6.h>
#include <linux/tcp.h>
#include <linux/ipv6.h>

#ifndef _HAVE_ARCH_IPV6_CSUM
__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, unsigned short proto,
__wsum csum);
#endif

static __inline__ __sum16 tcp_v6_check(int len,
const struct in6_addr *saddr,
const struct in6_addr *daddr,
__wsum base)
{
return csum_ipv6_magic(saddr, daddr, len, IPPROTO_TCP, base);
}

static inline void __tcp_v6_send_check(struct sk_buff *skb,
const struct in6_addr *saddr,
const struct in6_addr *daddr)
{
struct tcphdr *th = tcp_hdr(skb);

if (skb->ip_summed == CHECKSUM_PARTIAL) {
th->check = ~tcp_v6_check(skb->len, saddr, daddr, 0);
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct tcphdr, check);
} else {
th->check = tcp_v6_check(skb->len, saddr, daddr,
csum_partial(th, th->doff << 2,
skb->csum));
}
}

#if IS_ENABLED(CONFIG_IPV6)
static inline void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
{
struct ipv6_pinfo *np = inet6_sk(sk);

__tcp_v6_send_check(skb, &np->saddr, &sk->sk_v6_daddr);
}
#endif

int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto);
#endif