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294 lines
7.2 KiB
294 lines
7.2 KiB
// 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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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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rcu_read_lock(); |
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ptype = gro_find_receive_by_type(type); |
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if (!ptype) |
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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, |
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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_unlock: |
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rcu_read_unlock(); |
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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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rcu_read_lock(); |
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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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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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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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