v4.19.13 snapshot.
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
new file mode 100644
index 0000000..0c0522b
--- /dev/null
+++ b/net/ipv4/udp_offload.c
@@ -0,0 +1,486 @@
+/*
+ * IPV4 GSO/GRO offload support
+ * Linux INET 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.
+ *
+ * UDPv4 GSO support
+ */
+
+#include <linux/skbuff.h>
+#include <net/udp.h>
+#include <net/protocol.h>
+
+static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
+ netdev_features_t features,
+ struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
+ netdev_features_t features),
+ __be16 new_protocol, bool is_ipv6)
+{
+ int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
+ bool remcsum, need_csum, offload_csum, gso_partial;
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ struct udphdr *uh = udp_hdr(skb);
+ u16 mac_offset = skb->mac_header;
+ __be16 protocol = skb->protocol;
+ u16 mac_len = skb->mac_len;
+ int udp_offset, outer_hlen;
+ __wsum partial;
+ bool need_ipsec;
+
+ if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
+ goto out;
+
+ /* Adjust partial header checksum to negate old length.
+ * We cannot rely on the value contained in uh->len as it is
+ * possible that the actual value exceeds the boundaries of the
+ * 16 bit length field due to the header being added outside of an
+ * IP or IPv6 frame that was already limited to 64K - 1.
+ */
+ if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
+ partial = (__force __wsum)uh->len;
+ else
+ partial = (__force __wsum)htonl(skb->len);
+ partial = csum_sub(csum_unfold(uh->check), partial);
+
+ /* setup inner skb. */
+ skb->encapsulation = 0;
+ SKB_GSO_CB(skb)->encap_level = 0;
+ __skb_pull(skb, tnl_hlen);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, skb_inner_network_offset(skb));
+ skb->mac_len = skb_inner_network_offset(skb);
+ skb->protocol = new_protocol;
+
+ need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
+ skb->encap_hdr_csum = need_csum;
+
+ remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
+ skb->remcsum_offload = remcsum;
+
+ need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
+ /* Try to offload checksum if possible */
+ offload_csum = !!(need_csum &&
+ !need_ipsec &&
+ (skb->dev->features &
+ (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
+ (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
+
+ features &= skb->dev->hw_enc_features;
+
+ /* The only checksum offload we care about from here on out is the
+ * outer one so strip the existing checksum feature flags and
+ * instead set the flag based on our outer checksum offload value.
+ */
+ if (remcsum) {
+ features &= ~NETIF_F_CSUM_MASK;
+ if (!need_csum || offload_csum)
+ features |= NETIF_F_HW_CSUM;
+ }
+
+ /* segment inner packet. */
+ segs = gso_inner_segment(skb, features);
+ if (IS_ERR_OR_NULL(segs)) {
+ skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
+ mac_len);
+ goto out;
+ }
+
+ gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
+
+ outer_hlen = skb_tnl_header_len(skb);
+ udp_offset = outer_hlen - tnl_hlen;
+ skb = segs;
+ do {
+ unsigned int len;
+
+ if (remcsum)
+ skb->ip_summed = CHECKSUM_NONE;
+
+ /* Set up inner headers if we are offloading inner checksum */
+ if (skb->ip_summed == CHECKSUM_PARTIAL) {
+ skb_reset_inner_headers(skb);
+ skb->encapsulation = 1;
+ }
+
+ skb->mac_len = mac_len;
+ skb->protocol = protocol;
+
+ __skb_push(skb, outer_hlen);
+ skb_reset_mac_header(skb);
+ skb_set_network_header(skb, mac_len);
+ skb_set_transport_header(skb, udp_offset);
+ len = skb->len - udp_offset;
+ uh = udp_hdr(skb);
+
+ /* If we are only performing partial GSO the inner header
+ * will be using a length value equal to only one MSS sized
+ * segment instead of the entire frame.
+ */
+ if (gso_partial && skb_is_gso(skb)) {
+ uh->len = htons(skb_shinfo(skb)->gso_size +
+ SKB_GSO_CB(skb)->data_offset +
+ skb->head - (unsigned char *)uh);
+ } else {
+ uh->len = htons(len);
+ }
+
+ if (!need_csum)
+ continue;
+
+ uh->check = ~csum_fold(csum_add(partial,
+ (__force __wsum)htonl(len)));
+
+ if (skb->encapsulation || !offload_csum) {
+ uh->check = gso_make_checksum(skb, ~uh->check);
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
+ } else {
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ }
+ } while ((skb = skb->next));
+out:
+ return segs;
+}
+
+struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
+ netdev_features_t features,
+ bool is_ipv6)
+{
+ __be16 protocol = skb->protocol;
+ const struct net_offload **offloads;
+ const struct net_offload *ops;
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
+ netdev_features_t features);
+
+ rcu_read_lock();
+
+ switch (skb->inner_protocol_type) {
+ case ENCAP_TYPE_ETHER:
+ protocol = skb->inner_protocol;
+ gso_inner_segment = skb_mac_gso_segment;
+ break;
+ case ENCAP_TYPE_IPPROTO:
+ offloads = is_ipv6 ? inet6_offloads : inet_offloads;
+ ops = rcu_dereference(offloads[skb->inner_ipproto]);
+ if (!ops || !ops->callbacks.gso_segment)
+ goto out_unlock;
+ gso_inner_segment = ops->callbacks.gso_segment;
+ break;
+ default:
+ goto out_unlock;
+ }
+
+ segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
+ protocol, is_ipv6);
+
+out_unlock:
+ rcu_read_unlock();
+
+ return segs;
+}
+EXPORT_SYMBOL(skb_udp_tunnel_segment);
+
+struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
+ netdev_features_t features)
+{
+ struct sock *sk = gso_skb->sk;
+ unsigned int sum_truesize = 0;
+ struct sk_buff *segs, *seg;
+ struct udphdr *uh;
+ unsigned int mss;
+ bool copy_dtor;
+ __sum16 check;
+ __be16 newlen;
+
+ mss = skb_shinfo(gso_skb)->gso_size;
+ if (gso_skb->len <= sizeof(*uh) + mss)
+ return ERR_PTR(-EINVAL);
+
+ skb_pull(gso_skb, sizeof(*uh));
+
+ /* clear destructor to avoid skb_segment assigning it to tail */
+ copy_dtor = gso_skb->destructor == sock_wfree;
+ if (copy_dtor)
+ gso_skb->destructor = NULL;
+
+ segs = skb_segment(gso_skb, features);
+ if (unlikely(IS_ERR_OR_NULL(segs))) {
+ if (copy_dtor)
+ gso_skb->destructor = sock_wfree;
+ return segs;
+ }
+
+ /* GSO partial and frag_list segmentation only requires splitting
+ * the frame into an MSS multiple and possibly a remainder, both
+ * cases return a GSO skb. So update the mss now.
+ */
+ if (skb_is_gso(segs))
+ mss *= skb_shinfo(segs)->gso_segs;
+
+ seg = segs;
+ uh = udp_hdr(seg);
+
+ /* compute checksum adjustment based on old length versus new */
+ newlen = htons(sizeof(*uh) + mss);
+ check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
+
+ for (;;) {
+ if (copy_dtor) {
+ seg->destructor = sock_wfree;
+ seg->sk = sk;
+ sum_truesize += seg->truesize;
+ }
+
+ if (!seg->next)
+ break;
+
+ uh->len = newlen;
+ uh->check = check;
+
+ if (seg->ip_summed == CHECKSUM_PARTIAL)
+ gso_reset_checksum(seg, ~check);
+ else
+ uh->check = gso_make_checksum(seg, ~check) ? :
+ CSUM_MANGLED_0;
+
+ seg = seg->next;
+ uh = udp_hdr(seg);
+ }
+
+ /* last packet can be partial gso_size, account for that in checksum */
+ newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
+ seg->data_len);
+ check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
+
+ uh->len = newlen;
+ uh->check = check;
+
+ if (seg->ip_summed == CHECKSUM_PARTIAL)
+ gso_reset_checksum(seg, ~check);
+ else
+ uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
+
+ /* update refcount for the packet */
+ if (copy_dtor) {
+ int delta = sum_truesize - gso_skb->truesize;
+
+ /* In some pathological cases, delta can be negative.
+ * We need to either use refcount_add() or refcount_sub_and_test()
+ */
+ if (likely(delta >= 0))
+ refcount_add(delta, &sk->sk_wmem_alloc);
+ else
+ WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
+ }
+ return segs;
+}
+EXPORT_SYMBOL_GPL(__udp_gso_segment);
+
+static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
+ netdev_features_t features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ unsigned int mss;
+ __wsum csum;
+ struct udphdr *uh;
+ struct iphdr *iph;
+
+ if (skb->encapsulation &&
+ (skb_shinfo(skb)->gso_type &
+ (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
+ segs = skb_udp_tunnel_segment(skb, features, false);
+ goto out;
+ }
+
+ 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);
+
+ mss = skb_shinfo(skb)->gso_size;
+ if (unlikely(skb->len <= mss))
+ goto out;
+
+ /* 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);
+ iph = ip_hdr(skb);
+
+ uh->check = 0;
+ csum = skb_checksum(skb, 0, skb->len, 0);
+ uh->check = udp_v4_check(skb->len, iph->saddr, iph->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;
+
+ /* Fragment the skb. IP headers of the fragments are updated in
+ * inet_gso_segment()
+ */
+ segs = skb_segment(skb, features);
+out:
+ return segs;
+}
+
+struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
+ struct udphdr *uh, udp_lookup_t lookup)
+{
+ struct sk_buff *pp = NULL;
+ struct sk_buff *p;
+ struct udphdr *uh2;
+ unsigned int off = skb_gro_offset(skb);
+ int flush = 1;
+ struct sock *sk;
+
+ if (NAPI_GRO_CB(skb)->encap_mark ||
+ (skb->ip_summed != CHECKSUM_PARTIAL &&
+ NAPI_GRO_CB(skb)->csum_cnt == 0 &&
+ !NAPI_GRO_CB(skb)->csum_valid))
+ goto out;
+
+ /* mark that this skb passed once through the tunnel gro layer */
+ NAPI_GRO_CB(skb)->encap_mark = 1;
+
+ rcu_read_lock();
+ sk = (*lookup)(skb, uh->source, uh->dest);
+
+ if (sk && udp_sk(sk)->gro_receive)
+ goto unflush;
+ goto out_unlock;
+
+unflush:
+ flush = 0;
+
+ list_for_each_entry(p, head, list) {
+ if (!NAPI_GRO_CB(p)->same_flow)
+ continue;
+
+ uh2 = (struct udphdr *)(p->data + off);
+
+ /* Match ports and either checksums are either both zero
+ * or nonzero.
+ */
+ if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
+ (!uh->check ^ !uh2->check)) {
+ NAPI_GRO_CB(p)->same_flow = 0;
+ continue;
+ }
+ }
+
+ skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
+ skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
+ pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
+
+out_unlock:
+ rcu_read_unlock();
+out:
+ skb_gro_flush_final(skb, pp, flush);
+ return pp;
+}
+EXPORT_SYMBOL(udp_gro_receive);
+
+static struct sk_buff *udp4_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,
+ inet_gro_compute_pseudo))
+ goto flush;
+ else if (uh->check)
+ skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
+ inet_gro_compute_pseudo);
+skip:
+ NAPI_GRO_CB(skb)->is_ipv6 = 0;
+ return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb);
+
+flush:
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
+}
+
+int udp_gro_complete(struct sk_buff *skb, int nhoff,
+ udp_lookup_t lookup)
+{
+ __be16 newlen = htons(skb->len - nhoff);
+ struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
+ int err = -ENOSYS;
+ struct sock *sk;
+
+ uh->len = newlen;
+
+ /* Set encapsulation before calling into inner gro_complete() functions
+ * to make them set up the inner offsets.
+ */
+ skb->encapsulation = 1;
+
+ rcu_read_lock();
+ sk = (*lookup)(skb, uh->source, uh->dest);
+ if (sk && udp_sk(sk)->gro_complete)
+ err = udp_sk(sk)->gro_complete(sk, skb,
+ nhoff + sizeof(struct udphdr));
+ rcu_read_unlock();
+
+ if (skb->remcsum_offload)
+ skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM;
+
+ return err;
+}
+EXPORT_SYMBOL(udp_gro_complete);
+
+static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
+{
+ const struct iphdr *iph = ip_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_v4_check(skb->len - nhoff, iph->saddr,
+ iph->daddr, 0);
+ } else {
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
+ }
+
+ return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
+}
+
+static const struct net_offload udpv4_offload = {
+ .callbacks = {
+ .gso_segment = udp4_ufo_fragment,
+ .gro_receive = udp4_gro_receive,
+ .gro_complete = udp4_gro_complete,
+ },
+};
+
+int __init udpv4_offload_init(void)
+{
+ return inet_add_offload(&udpv4_offload, IPPROTO_UDP);
+}