mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
565 lines
15 KiB
C
565 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* IPV4 GSO/GRO offload support
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* Linux INET implementation
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*
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* UDPv4 GSO support
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*/
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#include <linux/skbuff.h>
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#include <net/udp.h>
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#include <net/protocol.h>
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#include <net/inet_common.h>
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static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
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netdev_features_t features,
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struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
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netdev_features_t features),
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__be16 new_protocol, bool is_ipv6)
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{
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int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
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bool remcsum, need_csum, offload_csum, gso_partial;
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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struct udphdr *uh = udp_hdr(skb);
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u16 mac_offset = skb->mac_header;
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__be16 protocol = skb->protocol;
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u16 mac_len = skb->mac_len;
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int udp_offset, outer_hlen;
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__wsum partial;
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bool need_ipsec;
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if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
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goto out;
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/* Adjust partial header checksum to negate old length.
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* We cannot rely on the value contained in uh->len as it is
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* possible that the actual value exceeds the boundaries of the
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* 16 bit length field due to the header being added outside of an
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* IP or IPv6 frame that was already limited to 64K - 1.
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*/
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if (skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL)
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partial = (__force __wsum)uh->len;
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else
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partial = (__force __wsum)htonl(skb->len);
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partial = csum_sub(csum_unfold(uh->check), partial);
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/* setup inner skb. */
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skb->encapsulation = 0;
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SKB_GSO_CB(skb)->encap_level = 0;
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__skb_pull(skb, tnl_hlen);
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skb_reset_mac_header(skb);
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skb_set_network_header(skb, skb_inner_network_offset(skb));
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skb->mac_len = skb_inner_network_offset(skb);
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skb->protocol = new_protocol;
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need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
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skb->encap_hdr_csum = need_csum;
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remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
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skb->remcsum_offload = remcsum;
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need_ipsec = skb_dst(skb) && dst_xfrm(skb_dst(skb));
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/* Try to offload checksum if possible */
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offload_csum = !!(need_csum &&
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!need_ipsec &&
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(skb->dev->features &
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(is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) :
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(NETIF_F_HW_CSUM | NETIF_F_IP_CSUM))));
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features &= skb->dev->hw_enc_features;
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/* The only checksum offload we care about from here on out is the
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* outer one so strip the existing checksum feature flags and
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* instead set the flag based on our outer checksum offload value.
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*/
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if (remcsum) {
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features &= ~NETIF_F_CSUM_MASK;
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if (!need_csum || offload_csum)
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features |= NETIF_F_HW_CSUM;
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}
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/* segment inner packet. */
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segs = gso_inner_segment(skb, features);
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if (IS_ERR_OR_NULL(segs)) {
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skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
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mac_len);
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goto out;
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}
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gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
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outer_hlen = skb_tnl_header_len(skb);
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udp_offset = outer_hlen - tnl_hlen;
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skb = segs;
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do {
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unsigned int len;
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if (remcsum)
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skb->ip_summed = CHECKSUM_NONE;
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/* Set up inner headers if we are offloading inner checksum */
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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skb_reset_inner_headers(skb);
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skb->encapsulation = 1;
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}
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skb->mac_len = mac_len;
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skb->protocol = protocol;
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__skb_push(skb, outer_hlen);
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skb_reset_mac_header(skb);
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skb_set_network_header(skb, mac_len);
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skb_set_transport_header(skb, udp_offset);
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len = skb->len - udp_offset;
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uh = udp_hdr(skb);
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/* If we are only performing partial GSO the inner header
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* will be using a length value equal to only one MSS sized
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* segment instead of the entire frame.
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*/
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if (gso_partial && skb_is_gso(skb)) {
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uh->len = htons(skb_shinfo(skb)->gso_size +
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SKB_GSO_CB(skb)->data_offset +
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skb->head - (unsigned char *)uh);
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} else {
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uh->len = htons(len);
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}
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if (!need_csum)
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continue;
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uh->check = ~csum_fold(csum_add(partial,
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(__force __wsum)htonl(len)));
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if (skb->encapsulation || !offload_csum) {
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uh->check = gso_make_checksum(skb, ~uh->check);
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if (uh->check == 0)
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uh->check = CSUM_MANGLED_0;
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} else {
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = skb_transport_header(skb) - skb->head;
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skb->csum_offset = offsetof(struct udphdr, check);
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}
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} while ((skb = skb->next));
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out:
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return segs;
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}
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struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
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netdev_features_t features,
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bool is_ipv6)
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{
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__be16 protocol = skb->protocol;
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const struct net_offload **offloads;
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const struct net_offload *ops;
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb,
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netdev_features_t features);
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rcu_read_lock();
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switch (skb->inner_protocol_type) {
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case ENCAP_TYPE_ETHER:
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protocol = skb->inner_protocol;
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gso_inner_segment = skb_mac_gso_segment;
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break;
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case ENCAP_TYPE_IPPROTO:
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offloads = is_ipv6 ? inet6_offloads : inet_offloads;
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ops = rcu_dereference(offloads[skb->inner_ipproto]);
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if (!ops || !ops->callbacks.gso_segment)
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goto out_unlock;
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gso_inner_segment = ops->callbacks.gso_segment;
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break;
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default:
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goto out_unlock;
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}
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segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment,
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protocol, is_ipv6);
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out_unlock:
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rcu_read_unlock();
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return segs;
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}
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EXPORT_SYMBOL(skb_udp_tunnel_segment);
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struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
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netdev_features_t features)
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{
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struct sock *sk = gso_skb->sk;
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unsigned int sum_truesize = 0;
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struct sk_buff *segs, *seg;
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struct udphdr *uh;
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unsigned int mss;
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bool copy_dtor;
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__sum16 check;
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__be16 newlen;
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mss = skb_shinfo(gso_skb)->gso_size;
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if (gso_skb->len <= sizeof(*uh) + mss)
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return ERR_PTR(-EINVAL);
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skb_pull(gso_skb, sizeof(*uh));
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/* clear destructor to avoid skb_segment assigning it to tail */
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copy_dtor = gso_skb->destructor == sock_wfree;
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if (copy_dtor)
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gso_skb->destructor = NULL;
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segs = skb_segment(gso_skb, features);
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if (IS_ERR_OR_NULL(segs)) {
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if (copy_dtor)
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gso_skb->destructor = sock_wfree;
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return segs;
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}
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/* GSO partial and frag_list segmentation only requires splitting
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* the frame into an MSS multiple and possibly a remainder, both
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* cases return a GSO skb. So update the mss now.
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*/
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if (skb_is_gso(segs))
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mss *= skb_shinfo(segs)->gso_segs;
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seg = segs;
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uh = udp_hdr(seg);
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/* preserve TX timestamp flags and TS key for first segment */
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skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey;
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skb_shinfo(seg)->tx_flags |=
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(skb_shinfo(gso_skb)->tx_flags & SKBTX_ANY_TSTAMP);
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/* compute checksum adjustment based on old length versus new */
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newlen = htons(sizeof(*uh) + mss);
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check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
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for (;;) {
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if (copy_dtor) {
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seg->destructor = sock_wfree;
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seg->sk = sk;
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sum_truesize += seg->truesize;
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}
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if (!seg->next)
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break;
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uh->len = newlen;
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uh->check = check;
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if (seg->ip_summed == CHECKSUM_PARTIAL)
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gso_reset_checksum(seg, ~check);
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else
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uh->check = gso_make_checksum(seg, ~check) ? :
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CSUM_MANGLED_0;
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seg = seg->next;
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uh = udp_hdr(seg);
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}
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/* last packet can be partial gso_size, account for that in checksum */
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newlen = htons(skb_tail_pointer(seg) - skb_transport_header(seg) +
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seg->data_len);
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check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
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uh->len = newlen;
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uh->check = check;
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if (seg->ip_summed == CHECKSUM_PARTIAL)
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gso_reset_checksum(seg, ~check);
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else
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uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
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/* update refcount for the packet */
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if (copy_dtor) {
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int delta = sum_truesize - gso_skb->truesize;
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/* In some pathological cases, delta can be negative.
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* We need to either use refcount_add() or refcount_sub_and_test()
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*/
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if (likely(delta >= 0))
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refcount_add(delta, &sk->sk_wmem_alloc);
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else
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WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
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}
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return segs;
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}
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EXPORT_SYMBOL_GPL(__udp_gso_segment);
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static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
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netdev_features_t features)
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{
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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unsigned int mss;
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__wsum csum;
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struct udphdr *uh;
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struct iphdr *iph;
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if (skb->encapsulation &&
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(skb_shinfo(skb)->gso_type &
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(SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) {
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segs = skb_udp_tunnel_segment(skb, features, false);
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goto out;
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}
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if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
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goto out;
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if (!pskb_may_pull(skb, sizeof(struct udphdr)))
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goto out;
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if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
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return __udp_gso_segment(skb, features);
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mss = skb_shinfo(skb)->gso_size;
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if (unlikely(skb->len <= mss))
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goto out;
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/* Do software UFO. Complete and fill in the UDP checksum as
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* HW cannot do checksum of UDP packets sent as multiple
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* IP fragments.
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*/
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uh = udp_hdr(skb);
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iph = ip_hdr(skb);
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uh->check = 0;
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csum = skb_checksum(skb, 0, skb->len, 0);
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uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum);
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if (uh->check == 0)
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uh->check = CSUM_MANGLED_0;
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skb->ip_summed = CHECKSUM_UNNECESSARY;
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/* If there is no outer header we can fake a checksum offload
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* due to the fact that we have already done the checksum in
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* software prior to segmenting the frame.
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*/
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if (!skb->encap_hdr_csum)
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features |= NETIF_F_HW_CSUM;
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/* Fragment the skb. IP headers of the fragments are updated in
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* inet_gso_segment()
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*/
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segs = skb_segment(skb, features);
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out:
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return segs;
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}
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#define UDP_GRO_CNT_MAX 64
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static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
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struct sk_buff *skb)
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{
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struct udphdr *uh = udp_hdr(skb);
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struct sk_buff *pp = NULL;
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struct udphdr *uh2;
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struct sk_buff *p;
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unsigned int ulen;
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/* requires non zero csum, for symmetry with GSO */
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if (!uh->check) {
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NAPI_GRO_CB(skb)->flush = 1;
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return NULL;
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}
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/* Do not deal with padded or malicious packets, sorry ! */
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ulen = ntohs(uh->len);
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if (ulen <= sizeof(*uh) || ulen != skb_gro_len(skb)) {
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NAPI_GRO_CB(skb)->flush = 1;
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return NULL;
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}
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/* pull encapsulating udp header */
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skb_gro_pull(skb, sizeof(struct udphdr));
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skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
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list_for_each_entry(p, head, list) {
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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uh2 = udp_hdr(p);
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/* Match ports only, as csum is always non zero */
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if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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/* Terminate the flow on len mismatch or if it grow "too much".
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* Under small packet flood GRO count could elsewhere grow a lot
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* leading to excessive truesize values.
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* On len mismatch merge the first packet shorter than gso_size,
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* otherwise complete the GRO packet.
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*/
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if (ulen > ntohs(uh2->len) || skb_gro_receive(p, skb) ||
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ulen != ntohs(uh2->len) ||
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NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
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pp = p;
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return pp;
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}
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/* mismatch, but we never need to flush */
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return NULL;
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}
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INDIRECT_CALLABLE_DECLARE(struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
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__be16 sport, __be16 dport));
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struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
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struct udphdr *uh, udp_lookup_t lookup)
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{
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struct sk_buff *pp = NULL;
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struct sk_buff *p;
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struct udphdr *uh2;
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unsigned int off = skb_gro_offset(skb);
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int flush = 1;
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struct sock *sk;
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rcu_read_lock();
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sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
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udp4_lib_lookup_skb, skb, uh->source, uh->dest);
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if (!sk)
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goto out_unlock;
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if (udp_sk(sk)->gro_enabled) {
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pp = call_gro_receive(udp_gro_receive_segment, head, skb);
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rcu_read_unlock();
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return pp;
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}
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if (NAPI_GRO_CB(skb)->encap_mark ||
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(skb->ip_summed != CHECKSUM_PARTIAL &&
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NAPI_GRO_CB(skb)->csum_cnt == 0 &&
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!NAPI_GRO_CB(skb)->csum_valid) ||
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!udp_sk(sk)->gro_receive)
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goto out_unlock;
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/* mark that this skb passed once through the tunnel gro layer */
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NAPI_GRO_CB(skb)->encap_mark = 1;
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flush = 0;
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list_for_each_entry(p, head, list) {
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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uh2 = (struct udphdr *)(p->data + off);
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/* Match ports and either checksums are either both zero
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* or nonzero.
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*/
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if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) ||
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(!uh->check ^ !uh2->check)) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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}
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skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
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skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
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pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
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out_unlock:
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rcu_read_unlock();
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skb_gro_flush_final(skb, pp, flush);
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return pp;
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}
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EXPORT_SYMBOL(udp_gro_receive);
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INDIRECT_CALLABLE_SCOPE
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struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb)
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{
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struct udphdr *uh = udp_gro_udphdr(skb);
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if (unlikely(!uh) || !static_branch_unlikely(&udp_encap_needed_key))
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goto flush;
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/* Don't bother verifying checksum if we're going to flush anyway. */
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if (NAPI_GRO_CB(skb)->flush)
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goto skip;
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if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check,
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inet_gro_compute_pseudo))
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goto flush;
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else if (uh->check)
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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;
|
|
}
|
|
|
|
static int udp_gro_complete_segment(struct sk_buff *skb)
|
|
{
|
|
struct udphdr *uh = udp_hdr(skb);
|
|
|
|
skb->csum_start = (unsigned char *)uh - skb->head;
|
|
skb->csum_offset = offsetof(struct udphdr, check);
|
|
skb->ip_summed = CHECKSUM_PARTIAL;
|
|
|
|
skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
|
|
skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
|
|
rcu_read_lock();
|
|
sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
|
|
udp4_lib_lookup_skb, skb, uh->source, uh->dest);
|
|
if (sk && udp_sk(sk)->gro_enabled) {
|
|
err = udp_gro_complete_segment(skb);
|
|
} else if (sk && udp_sk(sk)->gro_complete) {
|
|
skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
|
|
: SKB_GSO_UDP_TUNNEL;
|
|
|
|
/* Set encapsulation before calling into inner gro_complete()
|
|
* functions to make them set up the inner offsets.
|
|
*/
|
|
skb->encapsulation = 1;
|
|
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);
|
|
|
|
INDIRECT_CALLABLE_SCOPE 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)
|
|
uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
|
|
iph->daddr, 0);
|
|
|
|
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);
|
|
}
|