net: ipv6: seg6_iptunnel: mitigate 2-realloc issue
This patch mitigates the two-reallocations issue with seg6_iptunnel by providing the dst_entry (in the cache) to the first call to skb_cow_head(). As a result, the very first iteration would still trigger two reallocations (i.e., empty cache), while next iterations would only trigger a single reallocation. Performance tests before/after applying this patch, which clearly shows the improvement: - before: https://ibb.co/3Cg4sNH - after: https://ibb.co/8rQ350r Signed-off-by: Justin Iurman <justin.iurman@uliege.be> Cc: David Lebrun <dlebrun@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Justin Iurman
Paolo Abeni
parent
dce525185b
commit
40475b6376
1 changed files with 52 additions and 33 deletions
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@ -124,8 +124,8 @@ static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
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return flowlabel;
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}
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/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
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int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
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static int __seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh,
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int proto, struct dst_entry *cache_dst)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct net *net = dev_net(dst->dev);
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@ -137,7 +137,7 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
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hdrlen = (osrh->hdrlen + 1) << 3;
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tot_len = hdrlen + sizeof(*hdr);
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err = skb_cow_head(skb, tot_len + skb->mac_len);
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err = skb_cow_head(skb, tot_len + dst_dev_overhead(cache_dst, skb));
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if (unlikely(err))
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return err;
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@ -197,11 +197,18 @@ int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
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return 0;
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}
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/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
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int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
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{
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return __seg6_do_srh_encap(skb, osrh, proto, NULL);
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}
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EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
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/* encapsulate an IPv6 packet within an outer IPv6 header with reduced SRH */
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static int seg6_do_srh_encap_red(struct sk_buff *skb,
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struct ipv6_sr_hdr *osrh, int proto)
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struct ipv6_sr_hdr *osrh, int proto,
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struct dst_entry *cache_dst)
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{
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__u8 first_seg = osrh->first_segment;
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struct dst_entry *dst = skb_dst(skb);
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@ -230,7 +237,7 @@ static int seg6_do_srh_encap_red(struct sk_buff *skb,
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tot_len = red_hdrlen + sizeof(struct ipv6hdr);
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err = skb_cow_head(skb, tot_len + skb->mac_len);
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err = skb_cow_head(skb, tot_len + dst_dev_overhead(cache_dst, skb));
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if (unlikely(err))
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return err;
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@ -317,8 +324,8 @@ out:
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return 0;
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}
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/* insert an SRH within an IPv6 packet, just after the IPv6 header */
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int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
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static int __seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh,
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struct dst_entry *cache_dst)
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{
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struct ipv6hdr *hdr, *oldhdr;
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struct ipv6_sr_hdr *isrh;
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@ -326,7 +333,7 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
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hdrlen = (osrh->hdrlen + 1) << 3;
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err = skb_cow_head(skb, hdrlen + skb->mac_len);
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err = skb_cow_head(skb, hdrlen + dst_dev_overhead(cache_dst, skb));
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if (unlikely(err))
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return err;
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@ -369,9 +376,8 @@ int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
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return 0;
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}
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EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
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static int seg6_do_srh(struct sk_buff *skb)
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static int seg6_do_srh(struct sk_buff *skb, struct dst_entry *cache_dst)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct seg6_iptunnel_encap *tinfo;
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@ -384,7 +390,7 @@ static int seg6_do_srh(struct sk_buff *skb)
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if (skb->protocol != htons(ETH_P_IPV6))
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return -EINVAL;
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err = seg6_do_srh_inline(skb, tinfo->srh);
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err = __seg6_do_srh_inline(skb, tinfo->srh, cache_dst);
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if (err)
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return err;
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break;
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@ -402,9 +408,11 @@ static int seg6_do_srh(struct sk_buff *skb)
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return -EINVAL;
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if (tinfo->mode == SEG6_IPTUN_MODE_ENCAP)
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err = seg6_do_srh_encap(skb, tinfo->srh, proto);
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err = __seg6_do_srh_encap(skb, tinfo->srh,
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proto, cache_dst);
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else
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err = seg6_do_srh_encap_red(skb, tinfo->srh, proto);
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err = seg6_do_srh_encap_red(skb, tinfo->srh,
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proto, cache_dst);
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if (err)
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return err;
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@ -425,11 +433,13 @@ static int seg6_do_srh(struct sk_buff *skb)
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skb_push(skb, skb->mac_len);
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if (tinfo->mode == SEG6_IPTUN_MODE_L2ENCAP)
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err = seg6_do_srh_encap(skb, tinfo->srh,
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IPPROTO_ETHERNET);
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err = __seg6_do_srh_encap(skb, tinfo->srh,
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IPPROTO_ETHERNET,
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cache_dst);
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else
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err = seg6_do_srh_encap_red(skb, tinfo->srh,
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IPPROTO_ETHERNET);
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IPPROTO_ETHERNET,
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cache_dst);
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if (err)
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return err;
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@ -444,6 +454,13 @@ static int seg6_do_srh(struct sk_buff *skb)
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return 0;
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}
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/* insert an SRH within an IPv6 packet, just after the IPv6 header */
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int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
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{
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return __seg6_do_srh_inline(skb, osrh, NULL);
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}
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EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
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static int seg6_input_finish(struct net *net, struct sock *sk,
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struct sk_buff *skb)
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{
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@ -458,31 +475,33 @@ static int seg6_input_core(struct net *net, struct sock *sk,
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struct seg6_lwt *slwt;
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int err;
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err = seg6_do_srh(skb);
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if (unlikely(err))
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goto drop;
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slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
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local_bh_disable();
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dst = dst_cache_get(&slwt->cache);
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local_bh_enable();
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err = seg6_do_srh(skb, dst);
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if (unlikely(err))
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goto drop;
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if (!dst) {
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ip6_route_input(skb);
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dst = skb_dst(skb);
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if (!dst->error) {
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local_bh_disable();
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dst_cache_set_ip6(&slwt->cache, dst,
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&ipv6_hdr(skb)->saddr);
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local_bh_enable();
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}
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err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
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if (unlikely(err))
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goto drop;
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} else {
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skb_dst_drop(skb);
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skb_dst_set(skb, dst);
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}
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local_bh_enable();
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err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
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if (unlikely(err))
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goto drop;
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if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
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return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
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@ -528,16 +547,16 @@ static int seg6_output_core(struct net *net, struct sock *sk,
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struct seg6_lwt *slwt;
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int err;
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err = seg6_do_srh(skb);
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if (unlikely(err))
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goto drop;
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slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
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local_bh_disable();
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dst = dst_cache_get(&slwt->cache);
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local_bh_enable();
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err = seg6_do_srh(skb, dst);
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if (unlikely(err))
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goto drop;
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if (unlikely(!dst)) {
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struct ipv6hdr *hdr = ipv6_hdr(skb);
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struct flowi6 fl6;
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@ -559,15 +578,15 @@ static int seg6_output_core(struct net *net, struct sock *sk,
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local_bh_disable();
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dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
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local_bh_enable();
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err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
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if (unlikely(err))
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goto drop;
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}
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skb_dst_drop(skb);
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skb_dst_set(skb, dst);
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err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
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if (unlikely(err))
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goto drop;
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if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
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return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb,
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NULL, skb_dst(skb)->dev, dst_output);
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