v4.19.13 snapshot.
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
new file mode 100644
index 0000000..95dee9c
--- /dev/null
+++ b/net/ipv6/udp_offload.c
@@ -0,0 +1,177 @@
+/*
+ * 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.
+ *
+ * UDPv6 GSO support
+ */
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <net/protocol.h>
+#include <net/ipv6.h>
+#include <net/udp.h>
+#include <net/ip6_checksum.h>
+#include "ip6_offload.h"
+
+static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ unsigned int mss;
+ unsigned int unfrag_ip6hlen, unfrag_len;
+ struct frag_hdr *fptr;
+ u8 *packet_start, *prevhdr;
+ u8 nexthdr;
+ u8 frag_hdr_sz = sizeof(struct frag_hdr);
+ __wsum csum;
+ int tnl_hlen;
+ int err;
+
+ mss = skb_shinfo(skb)->gso_size;
+ if (unlikely(skb->len <= mss))
+ goto out;
+
+ if (skb->encapsulation && skb_shinfo(skb)->gso_type &
+ (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))
+ segs = skb_udp_tunnel_segment(skb, features, true);
+ else {
+ const struct ipv6hdr *ipv6h;
+ struct udphdr *uh;
+
+ if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
+ goto out;
+
+ if (!pskb_may_pull(skb, sizeof(struct udphdr)))
+ goto out;
+
+ if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
+ return __udp_gso_segment(skb, features);
+
+ /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
+ * do checksum of UDP packets sent as multiple IP fragments.
+ */
+
+ uh = udp_hdr(skb);
+ ipv6h = ipv6_hdr(skb);
+
+ uh->check = 0;
+ csum = skb_checksum(skb, 0, skb->len, 0);
+ uh->check = udp_v6_check(skb->len, &ipv6h->saddr,
+ &ipv6h->daddr, csum);
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
+
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+ /* If there is no outer header we can fake a checksum offload
+ * due to the fact that we have already done the checksum in
+ * software prior to segmenting the frame.
+ */
+ if (!skb->encap_hdr_csum)
+ features |= NETIF_F_HW_CSUM;
+
+ /* Check if there is enough headroom to insert fragment header. */
+ tnl_hlen = skb_tnl_header_len(skb);
+ if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) {
+ if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz))
+ goto out;
+ }
+
+ /* Find the unfragmentable header and shift it left by frag_hdr_sz
+ * bytes to insert fragment header.
+ */
+ err = ip6_find_1stfragopt(skb, &prevhdr);
+ if (err < 0)
+ return ERR_PTR(err);
+ unfrag_ip6hlen = err;
+ nexthdr = *prevhdr;
+ *prevhdr = NEXTHDR_FRAGMENT;
+ unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) +
+ unfrag_ip6hlen + tnl_hlen;
+ packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset;
+ memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len);
+
+ SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz;
+ skb->mac_header -= frag_hdr_sz;
+ skb->network_header -= frag_hdr_sz;
+
+ fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
+ fptr->nexthdr = nexthdr;
+ fptr->reserved = 0;
+ fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb);
+
+ /* Fragment the skb. ipv6 header and the remaining fields of the
+ * fragment header are updated in ipv6_gso_segment()
+ */
+ segs = skb_segment(skb, features);
+ }
+
+out:
+ return segs;
+}
+
+static struct sk_buff *udp6_gro_receive(struct list_head *head,
+ struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_gro_udphdr(skb);
+
+ if (unlikely(!uh))
+ goto flush;
+
+ /* Don't bother verifying checksum if we're going to flush anyway. */
+ if (NAPI_GRO_CB(skb)->flush)
+ goto skip;
+
+ if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
+ ip6_gro_compute_pseudo))
+ goto flush;
+ else if (uh->check)
+ skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
+ ip6_gro_compute_pseudo);
+
+skip:
+ NAPI_GRO_CB(skb)->is_ipv6 = 1;
+ return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb);
+
+flush:
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
+}
+
+static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
+{
+ const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+ struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
+
+ if (uh->check) {
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+ uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
+ &ipv6h->daddr, 0);
+ } else {
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
+ }
+
+ return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
+}
+
+static const struct net_offload udpv6_offload = {
+ .callbacks = {
+ .gso_segment = udp6_ufo_fragment,
+ .gro_receive = udp6_gro_receive,
+ .gro_complete = udp6_gro_complete,
+ },
+};
+
+int udpv6_offload_init(void)
+{
+ return inet6_add_offload(&udpv6_offload, IPPROTO_UDP);
+}
+
+int udpv6_offload_exit(void)
+{
+ return inet6_del_offload(&udpv6_offload, IPPROTO_UDP);
+}