From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 11 Apr 2024 10:27:49 +0200
Subject: Adding upstream version 6.6.15.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 net/ipv6/ila/ila_common.c | 155 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 155 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 000000000..95e914691
--- /dev/null
+++ b/net/ipv6/ila/ila_common.c
@@ -0,0 +1,155 @@
+#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"
+
+void ila_init_saved_csum(struct ila_params *p)
+{
+	if (!p->locator_match.v64)
+		return;
+
+	p->csum_diff = compute_csum_diff8(
+				(__be32 *)&p->locator,
+				(__be32 *)&p->locator_match);
+}
+
+static __wsum get_csum_diff_iaddr(struct ila_addr *iaddr, struct ila_params *p)
+{
+	if (p->locator_match.v64)
+		return p->csum_diff;
+	else
+		return compute_csum_diff8((__be32 *)&p->locator,
+					  (__be32 *)&iaddr->loc);
+}
+
+static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
+{
+	return get_csum_diff_iaddr(ila_a2i(&ip6h->daddr), p);
+}
+
+static void ila_csum_do_neutral_fmt(struct ila_addr *iaddr,
+				    struct ila_params *p)
+{
+	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
+	__wsum diff, fval;
+
+	diff = get_csum_diff_iaddr(iaddr, p);
+
+	fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
+			CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG);
+
+	diff = csum_add(diff, fval);
+
+	*adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
+
+	/* Flip the csum-neutral bit. Either we are doing a SIR->ILA
+	 * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
+	 * and the C-bit is not set, or we are doing an ILA-SIR
+	 * tranlsation and the C-bit is set.
+	 */
+	iaddr->ident.csum_neutral ^= 1;
+}
+
+static void ila_csum_do_neutral_nofmt(struct ila_addr *iaddr,
+				      struct ila_params *p)
+{
+	__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
+	__wsum diff;
+
+	diff = get_csum_diff_iaddr(iaddr, p);
+
+	*adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
+}
+
+static void ila_csum_adjust_transport(struct sk_buff *skb,
+				      struct ila_params *p)
+{
+	size_t nhoff = sizeof(struct ipv6hdr);
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	__wsum diff;
+
+	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;
+	}
+}
+
+void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
+			     bool sir2ila)
+{
+	struct ipv6hdr *ip6h = ipv6_hdr(skb);
+	struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
+
+	switch (p->csum_mode) {
+	case ILA_CSUM_ADJUST_TRANSPORT:
+		ila_csum_adjust_transport(skb, p);
+		break;
+	case ILA_CSUM_NEUTRAL_MAP:
+		if (sir2ila) {
+			if (WARN_ON(ila_csum_neutral_set(iaddr->ident))) {
+				/* Checksum flag should never be
+				 * set in a formatted SIR address.
+				 */
+				break;
+			}
+		} else if (!ila_csum_neutral_set(iaddr->ident)) {
+			/* ILA to SIR translation and C-bit isn't
+			 * set so we're good.
+			 */
+			break;
+		}
+		ila_csum_do_neutral_fmt(iaddr, p);
+		break;
+	case ILA_CSUM_NEUTRAL_MAP_AUTO:
+		ila_csum_do_neutral_nofmt(iaddr, p);
+		break;
+	case ILA_CSUM_NO_ACTION:
+		break;
+	}
+
+	/* Now change destination address */
+	iaddr->loc = p->locator;
+}
-- 
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