![Tom Herbert](/assets/img/avatar_default.png)
Set the inner mac header to point to the GRE payload when
doing GRO. This is needed if we proceed to send the packet
through GRE GSO which now uses the inner mac header instead
of inner network header to determine the length of encapsulation
headers.
Fixes: 14051f0452
("gre: Use inner mac length when computing tunnel length")
Reported-by: Wolfgang Walter <linux@stwm.de>
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
269 lines
6.2 KiB
C
269 lines
6.2 KiB
C
/*
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* IPV4 GSO/GRO offload support
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* Linux INET implementation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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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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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struct sk_buff *segs = ERR_PTR(-EINVAL);
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netdev_features_t enc_features;
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int ghl;
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struct gre_base_hdr *greh;
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u16 mac_offset = skb->mac_header;
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int mac_len = skb->mac_len;
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__be16 protocol = skb->protocol;
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int tnl_hlen;
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bool csum;
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if (unlikely(skb_shinfo(skb)->gso_type &
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~(SKB_GSO_TCPV4 |
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SKB_GSO_TCPV6 |
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SKB_GSO_UDP |
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SKB_GSO_DODGY |
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SKB_GSO_TCP_ECN |
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SKB_GSO_GRE |
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SKB_GSO_GRE_CSUM |
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SKB_GSO_IPIP)))
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goto out;
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if (!skb->encapsulation)
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goto out;
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if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
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goto out;
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greh = (struct gre_base_hdr *)skb_transport_header(skb);
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ghl = skb_inner_mac_header(skb) - skb_transport_header(skb);
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if (unlikely(ghl < sizeof(*greh)))
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goto out;
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csum = !!(greh->flags & GRE_CSUM);
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if (csum)
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skb->encap_hdr_csum = 1;
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/* setup inner skb. */
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skb->protocol = greh->protocol;
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skb->encapsulation = 0;
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if (unlikely(!pskb_may_pull(skb, ghl)))
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goto out;
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__skb_pull(skb, ghl);
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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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/* segment inner packet. */
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enc_features = skb->dev->hw_enc_features & features;
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segs = skb_mac_gso_segment(skb, enc_features);
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if (IS_ERR_OR_NULL(segs)) {
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skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len);
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goto out;
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}
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skb = segs;
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tnl_hlen = skb_tnl_header_len(skb);
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do {
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__skb_push(skb, ghl);
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if (csum) {
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__be32 *pcsum;
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if (skb_has_shared_frag(skb)) {
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int err;
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err = __skb_linearize(skb);
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if (err) {
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kfree_skb_list(segs);
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segs = ERR_PTR(err);
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goto out;
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}
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}
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skb_reset_transport_header(skb);
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greh = (struct gre_base_hdr *)
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skb_transport_header(skb);
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pcsum = (__be32 *)(greh + 1);
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*pcsum = 0;
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*(__sum16 *)pcsum = gso_make_checksum(skb, 0);
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}
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__skb_push(skb, tnl_hlen - ghl);
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skb_reset_inner_headers(skb);
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skb->encapsulation = 1;
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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->mac_len = mac_len;
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skb->protocol = protocol;
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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 sk_buff **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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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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type = greh->protocol;
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rcu_read_lock();
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ptype = gro_find_receive_by_type(type);
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if (ptype == NULL)
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goto out_unlock;
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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_unlock;
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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_unlock;
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skb_gro_checksum_try_convert(skb, IPPROTO_GRE, 0,
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null_compute_pseudo);
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}
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flush = 0;
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for (p = *head; p; p = p->next) {
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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 = ptype->callbacks.gro_receive(head, skb);
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out_unlock:
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rcu_read_unlock();
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out:
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NAPI_GRO_CB(skb)->flush |= 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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rcu_read_lock();
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ptype = gro_find_complete_by_type(type);
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if (ptype != NULL)
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err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
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rcu_read_unlock();
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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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return inet_add_offload(&gre_offload, IPPROTO_GRE);
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}
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device_initcall(gre_offload_init);
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