ipv6: move csum_ipv6_magic() and udp6_csum_init() into static library

As suggested by David, udp6_csum_init() is too big to be inlined,
move it to ipv6 static library, net/ipv6/ip6_checksum.c.

And the generic csum_ipv6_magic() too.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 97 insertions, 0 deletions

diff --git a/net/ipv6/ip6_checksum.c b/net/ipv6/ip6_checksum.c
new file mode 100644
index 000000000000..72d198b8e4d2
--- /dev/null
+++ b/net/ipv6/ip6_checksum.c
@@ -0,0 +1,97 @@
+#include <net/ip.h>
+#include <net/udp.h>
+#include <net/udplite.h>
+#include <asm/checksum.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)
+{
+
+	int carry;
+	__u32 ulen;
+	__u32 uproto;
+	__u32 sum = (__force u32)csum;
+
+	sum += (__force u32)saddr->s6_addr32[0];
+	carry = (sum < (__force u32)saddr->s6_addr32[0]);
+	sum += carry;
+
+	sum += (__force u32)saddr->s6_addr32[1];
+	carry = (sum < (__force u32)saddr->s6_addr32[1]);
+	sum += carry;
+
+	sum += (__force u32)saddr->s6_addr32[2];
+	carry = (sum < (__force u32)saddr->s6_addr32[2]);
+	sum += carry;
+
+	sum += (__force u32)saddr->s6_addr32[3];
+	carry = (sum < (__force u32)saddr->s6_addr32[3]);
+	sum += carry;
+
+	sum += (__force u32)daddr->s6_addr32[0];
+	carry = (sum < (__force u32)daddr->s6_addr32[0]);
+	sum += carry;
+
+	sum += (__force u32)daddr->s6_addr32[1];
+	carry = (sum < (__force u32)daddr->s6_addr32[1]);
+	sum += carry;
+
+	sum += (__force u32)daddr->s6_addr32[2];
+	carry = (sum < (__force u32)daddr->s6_addr32[2]);
+	sum += carry;
+
+	sum += (__force u32)daddr->s6_addr32[3];
+	carry = (sum < (__force u32)daddr->s6_addr32[3]);
+	sum += carry;
+
+	ulen = (__force u32)htonl((__u32) len);
+	sum += ulen;
+	carry = (sum < ulen);
+	sum += carry;
+
+	uproto = (__force u32)htonl(proto);
+	sum += uproto;
+	carry = (sum < uproto);
+	sum += carry;
+
+	return csum_fold((__force __wsum)sum);
+}
+EXPORT_SYMBOL(csum_ipv6_magic);
+#endif
+
+int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
+{
+	int err;
+
+	UDP_SKB_CB(skb)->partial_cov = 0;
+	UDP_SKB_CB(skb)->cscov = skb->len;
+
+	if (proto == IPPROTO_UDPLITE) {
+		err = udplite_checksum_init(skb, uh);
+		if (err)
+			return err;
+	}
+
+	if (uh->check == 0) {
+		/* RFC 2460 section 8.1 says that we SHOULD log
+		   this error. Well, it is reasonable.
+		 */
+		LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0\n");
+		return 1;
+	}
+	if (skb->ip_summed == CHECKSUM_COMPLETE &&
+	    !csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
+			     skb->len, proto, skb->csum))
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+	if (!skb_csum_unnecessary(skb))
+		skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
+							 &ipv6_hdr(skb)->daddr,
+							 skb->len, proto, 0));
+
+	return 0;
+}
+EXPORT_SYMBOL(udp6_csum_init);