![Willem de Bruijn](/assets/img/avatar_default.png)
Commit 121d57af30
("gso: validate gso_type in GSO handlers") added
gso_type validation to existing gso_segment callback functions, to
filter out illegal and potentially dangerous SKB_GSO_DODGY packets.
Convert tunnels that now call inet_gso_segment and ipv6_gso_segment
directly to have their own callbacks and extend validation to these.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
454 lines
12 KiB
C
454 lines
12 KiB
C
/*
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* IPV6 GSO/GRO offload support
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* Linux INET6 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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#include <linux/kernel.h>
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#include <linux/socket.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/printk.h>
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#include <net/protocol.h>
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#include <net/ipv6.h>
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#include <net/inet_common.h>
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#include "ip6_offload.h"
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/* All GRO functions are always builtin, except UDP over ipv6, which lays in
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* ipv6 module, as it depends on UDPv6 lookup function, so we need special care
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* when ipv6 is built as a module
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*/
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#if IS_BUILTIN(CONFIG_IPV6)
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#define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
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#else
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#define INDIRECT_CALL_L4(f, f2, f1, ...) INDIRECT_CALL_1(f, f2, __VA_ARGS__)
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#endif
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#define indirect_call_gro_receive_l4(f2, f1, cb, head, skb) \
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({ \
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unlikely(gro_recursion_inc_test(skb)) ? \
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NAPI_GRO_CB(skb)->flush |= 1, NULL : \
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INDIRECT_CALL_L4(cb, f2, f1, head, skb); \
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})
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static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
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{
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const struct net_offload *ops = NULL;
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for (;;) {
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struct ipv6_opt_hdr *opth;
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int len;
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if (proto != NEXTHDR_HOP) {
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ops = rcu_dereference(inet6_offloads[proto]);
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if (unlikely(!ops))
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break;
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if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
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break;
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}
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if (unlikely(!pskb_may_pull(skb, 8)))
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break;
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opth = (void *)skb->data;
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len = ipv6_optlen(opth);
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if (unlikely(!pskb_may_pull(skb, len)))
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break;
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opth = (void *)skb->data;
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proto = opth->nexthdr;
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__skb_pull(skb, len);
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}
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return proto;
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}
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static struct sk_buff *ipv6_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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struct ipv6hdr *ipv6h;
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const struct net_offload *ops;
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int proto;
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struct frag_hdr *fptr;
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unsigned int payload_len;
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u8 *prevhdr;
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int offset = 0;
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bool encap, udpfrag;
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int nhoff;
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bool gso_partial;
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skb_reset_network_header(skb);
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nhoff = skb_network_header(skb) - skb_mac_header(skb);
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if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h))))
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goto out;
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encap = SKB_GSO_CB(skb)->encap_level > 0;
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if (encap)
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features &= skb->dev->hw_enc_features;
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SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
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ipv6h = ipv6_hdr(skb);
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__skb_pull(skb, sizeof(*ipv6h));
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segs = ERR_PTR(-EPROTONOSUPPORT);
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proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
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if (skb->encapsulation &&
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skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
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udpfrag = proto == IPPROTO_UDP && encap &&
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(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
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else
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udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
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(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
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ops = rcu_dereference(inet6_offloads[proto]);
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if (likely(ops && ops->callbacks.gso_segment)) {
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skb_reset_transport_header(skb);
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segs = ops->callbacks.gso_segment(skb, features);
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}
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if (IS_ERR_OR_NULL(segs))
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goto out;
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gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
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for (skb = segs; skb; skb = skb->next) {
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ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff);
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if (gso_partial && skb_is_gso(skb))
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payload_len = skb_shinfo(skb)->gso_size +
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SKB_GSO_CB(skb)->data_offset +
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skb->head - (unsigned char *)(ipv6h + 1);
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else
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payload_len = skb->len - nhoff - sizeof(*ipv6h);
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ipv6h->payload_len = htons(payload_len);
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skb->network_header = (u8 *)ipv6h - skb->head;
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skb_reset_mac_len(skb);
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if (udpfrag) {
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int err = ip6_find_1stfragopt(skb, &prevhdr);
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if (err < 0) {
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kfree_skb_list(segs);
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return ERR_PTR(err);
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}
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fptr = (struct frag_hdr *)((u8 *)ipv6h + err);
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fptr->frag_off = htons(offset);
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if (skb->next)
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fptr->frag_off |= htons(IP6_MF);
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offset += (ntohs(ipv6h->payload_len) -
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sizeof(struct frag_hdr));
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}
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if (encap)
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skb_reset_inner_headers(skb);
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}
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out:
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return segs;
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}
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/* Return the total length of all the extension hdrs, following the same
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* logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs.
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*/
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static int ipv6_exthdrs_len(struct ipv6hdr *iph,
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const struct net_offload **opps)
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{
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struct ipv6_opt_hdr *opth = (void *)iph;
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int len = 0, proto, optlen = sizeof(*iph);
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proto = iph->nexthdr;
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for (;;) {
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if (proto != NEXTHDR_HOP) {
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*opps = rcu_dereference(inet6_offloads[proto]);
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if (unlikely(!(*opps)))
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break;
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if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
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break;
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}
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opth = (void *)opth + optlen;
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optlen = ipv6_optlen(opth);
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len += optlen;
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proto = opth->nexthdr;
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}
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return len;
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}
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INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *,
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struct sk_buff *));
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INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
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struct sk_buff *));
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INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
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struct sk_buff *skb)
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{
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const struct net_offload *ops;
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struct sk_buff *pp = NULL;
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struct sk_buff *p;
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struct ipv6hdr *iph;
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unsigned int nlen;
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unsigned int hlen;
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unsigned int off;
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u16 flush = 1;
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int proto;
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off = skb_gro_offset(skb);
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hlen = off + sizeof(*iph);
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iph = skb_gro_header_fast(skb, off);
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if (skb_gro_header_hard(skb, hlen)) {
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iph = skb_gro_header_slow(skb, hlen, off);
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if (unlikely(!iph))
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goto out;
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}
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skb_set_network_header(skb, off);
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skb_gro_pull(skb, sizeof(*iph));
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skb_set_transport_header(skb, skb_gro_offset(skb));
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flush += ntohs(iph->payload_len) != skb_gro_len(skb);
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rcu_read_lock();
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proto = iph->nexthdr;
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ops = rcu_dereference(inet6_offloads[proto]);
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if (!ops || !ops->callbacks.gro_receive) {
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__pskb_pull(skb, skb_gro_offset(skb));
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skb_gro_frag0_invalidate(skb);
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proto = ipv6_gso_pull_exthdrs(skb, proto);
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skb_gro_pull(skb, -skb_transport_offset(skb));
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skb_reset_transport_header(skb);
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__skb_push(skb, skb_gro_offset(skb));
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ops = rcu_dereference(inet6_offloads[proto]);
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if (!ops || !ops->callbacks.gro_receive)
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goto out_unlock;
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iph = ipv6_hdr(skb);
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}
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NAPI_GRO_CB(skb)->proto = proto;
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flush--;
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nlen = skb_network_header_len(skb);
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list_for_each_entry(p, head, list) {
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const struct ipv6hdr *iph2;
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__be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */
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if (!NAPI_GRO_CB(p)->same_flow)
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continue;
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iph2 = (struct ipv6hdr *)(p->data + off);
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first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
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/* All fields must match except length and Traffic Class.
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* XXX skbs on the gro_list have all been parsed and pulled
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* already so we don't need to compare nlen
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* (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops)))
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* memcmp() alone below is sufficient, right?
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*/
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if ((first_word & htonl(0xF00FFFFF)) ||
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!ipv6_addr_equal(&iph->saddr, &iph2->saddr) ||
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!ipv6_addr_equal(&iph->daddr, &iph2->daddr) ||
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*(u16 *)&iph->nexthdr != *(u16 *)&iph2->nexthdr) {
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not_same_flow:
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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 (unlikely(nlen > sizeof(struct ipv6hdr))) {
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if (memcmp(iph + 1, iph2 + 1,
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nlen - sizeof(struct ipv6hdr)))
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goto not_same_flow;
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}
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/* flush if Traffic Class fields are different */
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NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000));
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NAPI_GRO_CB(p)->flush |= flush;
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/* If the previous IP ID value was based on an atomic
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* datagram we can overwrite the value and ignore it.
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*/
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if (NAPI_GRO_CB(skb)->is_atomic)
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NAPI_GRO_CB(p)->flush_id = 0;
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}
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NAPI_GRO_CB(skb)->is_atomic = true;
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NAPI_GRO_CB(skb)->flush |= flush;
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skb_gro_postpull_rcsum(skb, iph, nlen);
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pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive,
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ops->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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skb_gro_flush_final(skb, pp, flush);
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return pp;
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}
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static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
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struct sk_buff *skb)
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{
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/* Common GRO receive for SIT and IP6IP6 */
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if (NAPI_GRO_CB(skb)->encap_mark) {
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NAPI_GRO_CB(skb)->flush = 1;
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return NULL;
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}
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NAPI_GRO_CB(skb)->encap_mark = 1;
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return ipv6_gro_receive(head, skb);
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}
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static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
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struct sk_buff *skb)
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{
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/* Common GRO receive for SIT and IP6IP6 */
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if (NAPI_GRO_CB(skb)->encap_mark) {
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NAPI_GRO_CB(skb)->flush = 1;
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return NULL;
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}
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NAPI_GRO_CB(skb)->encap_mark = 1;
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return inet_gro_receive(head, skb);
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}
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INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *, int));
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INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
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INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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const struct net_offload *ops;
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struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
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int err = -ENOSYS;
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if (skb->encapsulation) {
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skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
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skb_set_inner_network_header(skb, nhoff);
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}
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iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
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rcu_read_lock();
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nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
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if (WARN_ON(!ops || !ops->callbacks.gro_complete))
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goto out_unlock;
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err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
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udp6_gro_complete, skb, nhoff);
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out_unlock:
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rcu_read_unlock();
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return err;
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}
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static int sit_gro_complete(struct sk_buff *skb, int nhoff)
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{
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
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return ipv6_gro_complete(skb, nhoff);
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}
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static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
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return ipv6_gro_complete(skb, nhoff);
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}
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static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
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{
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skb->encapsulation = 1;
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skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
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return inet_gro_complete(skb, nhoff);
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}
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static struct packet_offload ipv6_packet_offload __read_mostly = {
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.type = cpu_to_be16(ETH_P_IPV6),
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.callbacks = {
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.gso_segment = ipv6_gso_segment,
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.gro_receive = ipv6_gro_receive,
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.gro_complete = ipv6_gro_complete,
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},
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};
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static struct sk_buff *sit_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
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return ERR_PTR(-EINVAL);
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return ipv6_gso_segment(skb, features);
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}
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static struct sk_buff *ip4ip6_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
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return ERR_PTR(-EINVAL);
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return inet_gso_segment(skb, features);
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}
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static struct sk_buff *ip6ip6_gso_segment(struct sk_buff *skb,
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netdev_features_t features)
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{
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if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6))
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return ERR_PTR(-EINVAL);
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return ipv6_gso_segment(skb, features);
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}
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static const struct net_offload sit_offload = {
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.callbacks = {
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.gso_segment = sit_gso_segment,
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.gro_receive = sit_ip6ip6_gro_receive,
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.gro_complete = sit_gro_complete,
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},
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};
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static const struct net_offload ip4ip6_offload = {
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.callbacks = {
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.gso_segment = ip4ip6_gso_segment,
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.gro_receive = ip4ip6_gro_receive,
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.gro_complete = ip4ip6_gro_complete,
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},
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};
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static const struct net_offload ip6ip6_offload = {
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.callbacks = {
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.gso_segment = ip6ip6_gso_segment,
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.gro_receive = sit_ip6ip6_gro_receive,
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.gro_complete = ip6ip6_gro_complete,
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},
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};
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static int __init ipv6_offload_init(void)
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{
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if (tcpv6_offload_init() < 0)
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pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
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if (ipv6_exthdrs_offload_init() < 0)
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pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__);
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dev_add_offload(&ipv6_packet_offload);
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inet_add_offload(&sit_offload, IPPROTO_IPV6);
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inet6_add_offload(&ip6ip6_offload, IPPROTO_IPV6);
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inet6_add_offload(&ip4ip6_offload, IPPROTO_IPIP);
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return 0;
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}
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fs_initcall(ipv6_offload_init);
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