290 lines
7.2 KiB
C
290 lines
7.2 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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* GRE GSO support
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*/
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#include <linux/skbuff.h>
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#include <linux/init.h>
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#include <net/protocol.h>
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#include <net/gre.h>
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#include <net/gro.h>
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static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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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 need_csum, offload_csum, gso_partial, need_ipsec;
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struct sk_buff *segs = ERR_PTR(-EINVAL);
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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 gre_offset, outer_hlen;
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if (!skb->encapsulation)
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goto out;
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if (unlikely(tnl_hlen < sizeof(struct gre_base_hdr)))
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goto out;
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if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
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goto out;
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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 = skb->inner_protocol;
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need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_GRE_CSUM);
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skb->encap_hdr_csum = need_csum;
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features &= skb->dev->hw_enc_features;
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if (need_csum)
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features &= ~NETIF_F_SCTP_CRC;
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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 && !need_ipsec &&
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(skb->dev->features & NETIF_F_HW_CSUM));
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/* segment inner packet. */
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segs = skb_mac_gso_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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gre_offset = outer_hlen - tnl_hlen;
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skb = segs;
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do {
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struct gre_base_hdr *greh;
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__sum16 *pcsum;
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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, gre_offset);
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if (!need_csum)
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continue;
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greh = (struct gre_base_hdr *)skb_transport_header(skb);
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pcsum = (__sum16 *)(greh + 1);
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if (gso_partial && skb_is_gso(skb)) {
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unsigned int partial_adj;
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/* Adjust checksum to account for the fact that
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* the partial checksum is based on actual size
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* whereas headers should be based on MSS size.
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*/
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partial_adj = skb->len + skb_headroom(skb) -
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SKB_GSO_CB(skb)->data_offset -
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skb_shinfo(skb)->gso_size;
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*pcsum = ~csum_fold((__force __wsum)htonl(partial_adj));
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} else {
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*pcsum = 0;
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}
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*(pcsum + 1) = 0;
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if (skb->encapsulation || !offload_csum) {
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*pcsum = gso_make_checksum(skb, 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 = sizeof(*greh);
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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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static struct sk_buff *gre_gro_receive(struct list_head *head,
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struct sk_buff *skb)
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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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const struct gre_base_hdr *greh;
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unsigned int hlen, grehlen;
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unsigned int off;
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int flush = 1;
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struct packet_offload *ptype;
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__be16 type;
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if (NAPI_GRO_CB(skb)->encap_mark)
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goto out;
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NAPI_GRO_CB(skb)->encap_mark = 1;
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off = skb_gro_offset(skb);
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hlen = off + sizeof(*greh);
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greh = skb_gro_header_fast(skb, off);
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if (skb_gro_header_hard(skb, hlen)) {
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greh = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!greh))
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goto out;
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}
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/* Only support version 0 and K (key), C (csum) flags. Note that
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* although the support for the S (seq#) flag can be added easily
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* for GRO, this is problematic for GSO hence can not be enabled
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* here because a GRO pkt may end up in the forwarding path, thus
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* requiring GSO support to break it up correctly.
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*/
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if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0)
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goto out;
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/* We can only support GRE_CSUM if we can track the location of
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* the GRE header. In the case of FOU/GUE we cannot because the
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* outer UDP header displaces the GRE header leaving us in a state
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* of limbo.
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*/
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if ((greh->flags & GRE_CSUM) && NAPI_GRO_CB(skb)->is_fou)
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goto out;
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type = greh->protocol;
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ptype = gro_find_receive_by_type(type);
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if (!ptype)
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goto out;
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grehlen = GRE_HEADER_SECTION;
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if (greh->flags & GRE_KEY)
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grehlen += GRE_HEADER_SECTION;
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if (greh->flags & GRE_CSUM)
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grehlen += GRE_HEADER_SECTION;
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hlen = off + grehlen;
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if (skb_gro_header_hard(skb, hlen)) {
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greh = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!greh))
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goto out;
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}
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/* Don't bother verifying checksum if we're going to flush anyway. */
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if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) {
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if (skb_gro_checksum_simple_validate(skb))
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goto out;
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skb_gro_checksum_try_convert(skb, IPPROTO_GRE,
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null_compute_pseudo);
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}
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list_for_each_entry(p, head, list) {
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const struct gre_base_hdr *greh2;
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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/* The following checks are needed to ensure only pkts
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* from the same tunnel are considered for aggregation.
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* The criteria for "the same tunnel" includes:
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* 1) same version (we only support version 0 here)
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* 2) same protocol (we only support ETH_P_IP for now)
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* 3) same set of flags
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* 4) same key if the key field is present.
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*/
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greh2 = (struct gre_base_hdr *)(p->data + off);
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if (greh2->flags != greh->flags ||
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greh2->protocol != greh->protocol) {
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NAPI_GRO_CB(p)->same_flow = 0;
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continue;
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}
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if (greh->flags & GRE_KEY) {
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/* compare keys */
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if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) {
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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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}
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skb_gro_pull(skb, grehlen);
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/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
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skb_gro_postpull_rcsum(skb, greh, grehlen);
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pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
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flush = 0;
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out:
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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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static int gre_gro_complete(struct sk_buff *skb, int nhoff)
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{
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struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff);
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struct packet_offload *ptype;
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unsigned int grehlen = sizeof(*greh);
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int err = -ENOENT;
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__be16 type;
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type = SKB_GSO_GRE;
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type = greh->protocol;
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if (greh->flags & GRE_KEY)
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grehlen += GRE_HEADER_SECTION;
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if (greh->flags & GRE_CSUM)
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grehlen += GRE_HEADER_SECTION;
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ptype = gro_find_complete_by_type(type);
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if (ptype)
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err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
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skb_set_inner_mac_header(skb, nhoff + grehlen);
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return err;
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}
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static const struct net_offload gre_offload = {
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.callbacks = {
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.gso_segment = gre_gso_segment,
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.gro_receive = gre_gro_receive,
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.gro_complete = gre_gro_complete,
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},
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};
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static int __init gre_offload_init(void)
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{
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int err;
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err = inet_add_offload(&gre_offload, IPPROTO_GRE);
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#if IS_ENABLED(CONFIG_IPV6)
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if (err)
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return err;
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err = inet6_add_offload(&gre_offload, IPPROTO_GRE);
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if (err)
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inet_del_offload(&gre_offload, IPPROTO_GRE);
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#endif
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return err;
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}
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device_initcall(gre_offload_init);
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