From 33f11d16142b06588eedfc1dd8cf93790979a712 Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Tue, 15 Dec 2015 15:41:35 -0800
Subject: ila: Create net/ipv6/ila directory

Create ila directory in preparation for supporting other hooks in the
kernel than LWT for doing ILA. This includes:
  - Moving ila.c to ila/ila_lwt.c
  - Splitting out some common functions into ila_common.c

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/ila/ila_common.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 net/ipv6/ila/ila_common.c

(limited to 'net/ipv6/ila/ila_common.c')

diff --git a/net/ipv6/ila/ila_common.c b/net/ipv6/ila/ila_common.c
new file mode 100644
index 000000000000..64e1904991ac
--- /dev/null
+++ b/net/ipv6/ila/ila_common.c
@@ -0,0 +1,95 @@
+#include <linux/errno.h>
+#include <linux/ip.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/socket.h>
+#include <linux/types.h>
+#include <net/checksum.h>
+#include <net/ip.h>
+#include <net/ip6_fib.h>
+#include <net/lwtunnel.h>
+#include <net/protocol.h>
+#include <uapi/linux/ila.h>
+#include "ila.h"
+
+static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
+{
+	if (*(__be64 *)&ip6h->daddr == p->locator_match)
+		return p->csum_diff;
+	else
+		return compute_csum_diff8((__be32 *)&ip6h->daddr,
+					  (__be32 *)&p->locator);
+}
+
+void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
+{
+	__wsum diff;
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	size_t nhoff = sizeof(struct ipv6hdr);
+
+	/* First update checksum */
+	switch (ip6h->nexthdr) {
+	case NEXTHDR_TCP:
+		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
+			struct tcphdr *th = (struct tcphdr *)
+					(skb_network_header(skb) + nhoff);
+
+			diff = get_csum_diff(ip6h, p);
+			inet_proto_csum_replace_by_diff(&th->check, skb,
+							diff, true);
+		}
+		break;
+	case NEXTHDR_UDP:
+		if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
+			struct udphdr *uh = (struct udphdr *)
+					(skb_network_header(skb) + nhoff);
+
+			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
+				diff = get_csum_diff(ip6h, p);
+				inet_proto_csum_replace_by_diff(&uh->check, skb,
+								diff, true);
+				if (!uh->check)
+					uh->check = CSUM_MANGLED_0;
+			}
+		}
+		break;
+	case NEXTHDR_ICMP:
+		if (likely(pskb_may_pull(skb,
+					 nhoff + sizeof(struct icmp6hdr)))) {
+			struct icmp6hdr *ih = (struct icmp6hdr *)
+					(skb_network_header(skb) + nhoff);
+
+			diff = get_csum_diff(ip6h, p);
+			inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
+							diff, true);
+		}
+		break;
+	}
+
+	/* Now change destination address */
+	*(__be64 *)&ip6h->daddr = p->locator;
+}
+
+static int __init ila_init(void)
+{
+	int ret;
+
+	ret = ila_lwt_init();
+
+	if (ret)
+		goto fail_lwt;
+
+fail_lwt:
+	return ret;
+}
+
+static void __exit ila_fini(void)
+{
+	ila_lwt_fini();
+}
+
+module_init(ila_init);
+module_exit(ila_fini);
+MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
+MODULE_LICENSE("GPL");
-- 
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