ipv6: Separate tcp offload functionality

Pull TCPv6 offload functionality into its won file in preparation
for moving it out of the module.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 98 insertions, 0 deletions

diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
new file mode 100644
index 000000000000..edeafedba470
--- /dev/null
+++ b/net/ipv6/tcpv6_offload.c
@@ -0,0 +1,98 @@
+/*
+ *	IPV6 GSO/GRO offload support
+ *	Linux INET6 implementation
+ *
+ *	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.
+ *
+ *      TCPv6 GSO/GRO support
+ */
+#include <linux/skbuff.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/ip6_checksum.h>
+#include "ip6_offload.h"
+
+static int tcp_v6_gso_send_check(struct sk_buff *skb)
+{
+	const struct ipv6hdr *ipv6h;
+	struct tcphdr *th;
+
+	if (!pskb_may_pull(skb, sizeof(*th)))
+		return -EINVAL;
+
+	ipv6h = ipv6_hdr(skb);
+	th = tcp_hdr(skb);
+
+	th->check = 0;
+	skb->ip_summed = CHECKSUM_PARTIAL;
+	__tcp_v6_send_check(skb, &ipv6h->saddr, &ipv6h->daddr);
+	return 0;
+}
+
+static struct sk_buff **tcp6_gro_receive(struct sk_buff **head,
+					 struct sk_buff *skb)
+{
+	const struct ipv6hdr *iph = skb_gro_network_header(skb);
+	__wsum wsum;
+	__sum16 sum;
+
+	switch (skb->ip_summed) {
+	case CHECKSUM_COMPLETE:
+		if (!tcp_v6_check(skb_gro_len(skb), &iph->saddr, &iph->daddr,
+				  skb->csum)) {
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+			break;
+		}
+flush:
+		NAPI_GRO_CB(skb)->flush = 1;
+		return NULL;
+
+	case CHECKSUM_NONE:
+		wsum = ~csum_unfold(csum_ipv6_magic(&iph->saddr, &iph->daddr,
+						    skb_gro_len(skb),
+						    IPPROTO_TCP, 0));
+		sum = csum_fold(skb_checksum(skb,
+					     skb_gro_offset(skb),
+					     skb_gro_len(skb),
+					     wsum));
+		if (sum)
+			goto flush;
+
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+		break;
+	}
+
+	return tcp_gro_receive(head, skb);
+}
+
+static int tcp6_gro_complete(struct sk_buff *skb)
+{
+	const struct ipv6hdr *iph = ipv6_hdr(skb);
+	struct tcphdr *th = tcp_hdr(skb);
+
+	th->check = ~tcp_v6_check(skb->len - skb_transport_offset(skb),
+				  &iph->saddr, &iph->daddr, 0);
+	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+
+	return tcp_gro_complete(skb);
+}
+
+static const struct net_offload tcpv6_offload = {
+	.gso_send_check	=	tcp_v6_gso_send_check,
+	.gso_segment	=	tcp_tso_segment,
+	.gro_receive	=	tcp6_gro_receive,
+	.gro_complete	=	tcp6_gro_complete,
+};
+
+int __init tcpv6_offload_init(void)
+{
+	return inet6_add_offload(&tcpv6_offload, IPPROTO_TCP);
+}
+
+void tcpv6_offload_cleanup(void)
+{
+	inet6_del_offload(&tcpv6_offload, IPPROTO_TCP);
+}