1 files changed, 109 insertions, 0 deletions
diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c
new file mode 100644
index 000000000..1482259de
--- /dev/null
+++ b/net/mpls/mpls_gso.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	MPLS GSO Support
+ *
+ *	Authors: Simon Horman (horms@verge.net.au)
+ *
+ *	Based on: GSO portions of net/ipv4/gre.c
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/netdev_features.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/mpls.h>
+
+static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
+				       netdev_features_t features)
+{
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	u16 mac_offset = skb->mac_header;
+	netdev_features_t mpls_features;
+	u16 mac_len = skb->mac_len;
+	__be16 mpls_protocol;
+	unsigned int mpls_hlen;
+
+	skb_reset_network_header(skb);
+	mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
+	if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
+		goto out;
+	if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
+		goto out;
+
+	/* Setup inner SKB. */
+	mpls_protocol = skb->protocol;
+	skb->protocol = skb->inner_protocol;
+
+	__skb_pull(skb, mpls_hlen);
+
+	skb->mac_len = 0;
+	skb_reset_mac_header(skb);
+
+	/* Segment inner packet. */
+	mpls_features = skb->dev->mpls_features & features;
+	segs = skb_mac_gso_segment(skb, mpls_features);
+	if (IS_ERR_OR_NULL(segs)) {
+		skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
+				     mac_len);
+		goto out;
+	}
+	skb = segs;
+
+	mpls_hlen += mac_len;
+	do {
+		skb->mac_len = mac_len;
+		skb->protocol = mpls_protocol;
+
+		skb_reset_inner_network_header(skb);
+
+		__skb_push(skb, mpls_hlen);
+
+		skb_reset_mac_header(skb);
+		skb_set_network_header(skb, mac_len);
+	} while ((skb = skb->next));
+
+out:
+	return segs;
+}
+
+static struct packet_offload mpls_mc_offload __read_mostly = {
+	.type = cpu_to_be16(ETH_P_MPLS_MC),
+	.priority = 15,
+	.callbacks = {
+		.gso_segment    =	mpls_gso_segment,
+	},
+};
+
+static struct packet_offload mpls_uc_offload __read_mostly = {
+	.type = cpu_to_be16(ETH_P_MPLS_UC),
+	.priority = 15,
+	.callbacks = {
+		.gso_segment    =	mpls_gso_segment,
+	},
+};
+
+static int __init mpls_gso_init(void)
+{
+	pr_info("MPLS GSO support\n");
+
+	dev_add_offload(&mpls_uc_offload);
+	dev_add_offload(&mpls_mc_offload);
+
+	return 0;
+}
+
+static void __exit mpls_gso_exit(void)
+{
+	dev_remove_offload(&mpls_uc_offload);
+	dev_remove_offload(&mpls_mc_offload);
+}
+
+module_init(mpls_gso_init);
+module_exit(mpls_gso_exit);
+
+MODULE_DESCRIPTION("MPLS GSO support");
+MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
+MODULE_LICENSE("GPL");