131 строка
2.8 KiB
C
131 строка
2.8 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 <net/protocol.h>
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#include <net/gre.h>
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static int gre_gso_send_check(struct sk_buff *skb)
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{
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if (!skb->encapsulation)
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return -EINVAL;
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return 0;
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}
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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 = GRE_HEADER_SECTION;
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struct gre_base_hdr *greh;
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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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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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if (greh->flags & GRE_KEY)
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ghl += GRE_HEADER_SECTION;
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if (greh->flags & GRE_SEQ)
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ghl += GRE_HEADER_SECTION;
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if (greh->flags & GRE_CSUM) {
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ghl += GRE_HEADER_SECTION;
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csum = true;
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} else
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csum = false;
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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 & netif_skb_features(skb);
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segs = skb_mac_gso_segment(skb, enc_features);
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if (!segs || IS_ERR(segs))
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goto out;
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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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greh = (struct gre_base_hdr *)(skb->data);
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pcsum = (__be32 *)(greh + 1);
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*pcsum = 0;
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*(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 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 const struct net_offload gre_offload = {
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.callbacks = {
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.gso_send_check = gre_gso_send_check,
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.gso_segment = gre_gso_segment,
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},
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};
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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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void __exit gre_offload_exit(void)
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{
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inet_del_offload(&gre_offload, IPPROTO_GRE);
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}
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