![Xin Long](/assets/img/avatar_default.png)
In early time, when freeing a xdst, it would be inserted into dst_garbage.list first. Then if it's refcnt was still held somewhere, later it would be put into dst_busy_list in dst_gc_task(). When one dev was being unregistered, the dev of these dsts in dst_busy_list would be set with loopback_dev and put this dev. So that this dev's removal wouldn't get blocked, and avoid the kmsg warning: kernel:unregister_netdevice: waiting for veth0 to become \ free. Usage count = 2 However after Commit52df157f17
("xfrm: take refcnt of dst when creating struct xfrm_dst bundle"), the xdst will not be freed with dst gc, and this warning happens. To fix it, we need to find these xdsts that are still held by others when removing the dev, and free xdst's dev and set it with loopback_dev. But unfortunately after flow_cache for xfrm was deleted, no list tracks them anymore. So we need to save these xdsts somewhere to release the xdst's dev later. To make this easier, this patch is to reuse uncached_list to track xdsts, so that the dev refcnt can be released in the event NETDEV_UNREGISTER process of fib_netdev_notifier. Thanks to Florian, we could move forward this fix quickly. Fixes:52df157f17
("xfrm: take refcnt of dst when creating struct xfrm_dst bundle") Reported-by: Jianlin Shi <jishi@redhat.com> Reported-by: Hangbin Liu <liuhangbin@gmail.com> Tested-by: Eyal Birger <eyal.birger@gmail.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
437 lines
9.8 KiB
C
437 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* xfrm6_policy.c: based on xfrm4_policy.c
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*
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* Authors:
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* Mitsuru KANDA @USAGI
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* Kazunori MIYAZAWA @USAGI
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* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
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* IPv6 support
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* YOSHIFUJI Hideaki
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* Split up af-specific portion
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*
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*/
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <net/addrconf.h>
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#include <net/dst.h>
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#include <net/xfrm.h>
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#include <net/ip.h>
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#include <net/ipv6.h>
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#include <net/ip6_route.h>
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#include <net/l3mdev.h>
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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#include <net/mip6.h>
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#endif
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static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
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const xfrm_address_t *saddr,
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const xfrm_address_t *daddr,
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u32 mark)
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{
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struct flowi6 fl6;
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struct dst_entry *dst;
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int err;
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memset(&fl6, 0, sizeof(fl6));
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fl6.flowi6_oif = l3mdev_master_ifindex_by_index(net, oif);
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fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
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fl6.flowi6_mark = mark;
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memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
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if (saddr)
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memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
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dst = ip6_route_output(net, NULL, &fl6);
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err = dst->error;
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if (dst->error) {
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dst_release(dst);
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dst = ERR_PTR(err);
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}
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return dst;
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}
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static int xfrm6_get_saddr(struct net *net, int oif,
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xfrm_address_t *saddr, xfrm_address_t *daddr,
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u32 mark)
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{
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struct dst_entry *dst;
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struct net_device *dev;
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dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
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if (IS_ERR(dst))
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return -EHOSTUNREACH;
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dev = ip6_dst_idev(dst)->dev;
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ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
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dst_release(dst);
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return 0;
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}
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static int xfrm6_get_tos(const struct flowi *fl)
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{
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return 0;
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}
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static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
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int nfheader_len)
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{
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if (dst->ops->family == AF_INET6) {
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struct rt6_info *rt = (struct rt6_info *)dst;
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path->path_cookie = rt6_get_cookie(rt);
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}
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path->u.rt6.rt6i_nfheader_len = nfheader_len;
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return 0;
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}
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static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
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const struct flowi *fl)
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{
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struct rt6_info *rt = (struct rt6_info *)xdst->route;
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xdst->u.dst.dev = dev;
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dev_hold(dev);
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xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
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if (!xdst->u.rt6.rt6i_idev) {
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dev_put(dev);
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return -ENODEV;
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}
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/* Sheit... I remember I did this right. Apparently,
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* it was magically lost, so this code needs audit */
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xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
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RTF_LOCAL);
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xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
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xdst->u.rt6.rt6i_node = rt->rt6i_node;
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xdst->route_cookie = rt6_get_cookie(rt);
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xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
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xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
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xdst->u.rt6.rt6i_src = rt->rt6i_src;
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INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached);
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rt6_uncached_list_add(&xdst->u.rt6);
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atomic_inc(&dev_net(dev)->ipv6.rt6_stats->fib_rt_uncache);
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return 0;
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}
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static inline void
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_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
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{
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struct flowi6 *fl6 = &fl->u.ip6;
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int onlyproto = 0;
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const struct ipv6hdr *hdr = ipv6_hdr(skb);
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u16 offset = sizeof(*hdr);
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struct ipv6_opt_hdr *exthdr;
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const unsigned char *nh = skb_network_header(skb);
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u16 nhoff = IP6CB(skb)->nhoff;
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int oif = 0;
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u8 nexthdr;
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if (!nhoff)
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nhoff = offsetof(struct ipv6hdr, nexthdr);
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nexthdr = nh[nhoff];
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if (skb_dst(skb))
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oif = skb_dst(skb)->dev->ifindex;
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memset(fl6, 0, sizeof(struct flowi6));
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fl6->flowi6_mark = skb->mark;
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fl6->flowi6_oif = reverse ? skb->skb_iif : oif;
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fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
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fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
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while (nh + offset + 1 < skb->data ||
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pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
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nh = skb_network_header(skb);
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exthdr = (struct ipv6_opt_hdr *)(nh + offset);
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switch (nexthdr) {
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case NEXTHDR_FRAGMENT:
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onlyproto = 1;
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/* fall through */
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case NEXTHDR_ROUTING:
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case NEXTHDR_HOP:
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case NEXTHDR_DEST:
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offset += ipv6_optlen(exthdr);
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nexthdr = exthdr->nexthdr;
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exthdr = (struct ipv6_opt_hdr *)(nh + offset);
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break;
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case IPPROTO_UDP:
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case IPPROTO_UDPLITE:
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case IPPROTO_TCP:
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case IPPROTO_SCTP:
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case IPPROTO_DCCP:
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if (!onlyproto && (nh + offset + 4 < skb->data ||
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pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
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__be16 *ports;
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nh = skb_network_header(skb);
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ports = (__be16 *)(nh + offset);
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fl6->fl6_sport = ports[!!reverse];
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fl6->fl6_dport = ports[!reverse];
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}
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fl6->flowi6_proto = nexthdr;
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return;
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case IPPROTO_ICMPV6:
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if (!onlyproto && (nh + offset + 2 < skb->data ||
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pskb_may_pull(skb, nh + offset + 2 - skb->data))) {
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u8 *icmp;
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nh = skb_network_header(skb);
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icmp = (u8 *)(nh + offset);
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fl6->fl6_icmp_type = icmp[0];
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fl6->fl6_icmp_code = icmp[1];
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}
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fl6->flowi6_proto = nexthdr;
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return;
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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case IPPROTO_MH:
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offset += ipv6_optlen(exthdr);
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if (!onlyproto && (nh + offset + 3 < skb->data ||
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pskb_may_pull(skb, nh + offset + 3 - skb->data))) {
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struct ip6_mh *mh;
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nh = skb_network_header(skb);
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mh = (struct ip6_mh *)(nh + offset);
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fl6->fl6_mh_type = mh->ip6mh_type;
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}
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fl6->flowi6_proto = nexthdr;
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return;
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#endif
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/* XXX Why are there these headers? */
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case IPPROTO_AH:
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case IPPROTO_ESP:
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case IPPROTO_COMP:
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default:
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fl6->fl6_ipsec_spi = 0;
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fl6->flowi6_proto = nexthdr;
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return;
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}
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}
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}
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static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
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struct sk_buff *skb, u32 mtu)
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{
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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struct dst_entry *path = xdst->route;
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path->ops->update_pmtu(path, sk, skb, mtu);
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}
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static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
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struct sk_buff *skb)
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{
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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struct dst_entry *path = xdst->route;
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path->ops->redirect(path, sk, skb);
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}
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static void xfrm6_dst_destroy(struct dst_entry *dst)
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{
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struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
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if (likely(xdst->u.rt6.rt6i_idev))
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in6_dev_put(xdst->u.rt6.rt6i_idev);
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dst_destroy_metrics_generic(dst);
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if (xdst->u.rt6.rt6i_uncached_list)
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rt6_uncached_list_del(&xdst->u.rt6);
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xfrm_dst_destroy(xdst);
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}
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static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
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int unregister)
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{
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struct xfrm_dst *xdst;
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if (!unregister)
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return;
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xdst = (struct xfrm_dst *)dst;
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if (xdst->u.rt6.rt6i_idev->dev == dev) {
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struct inet6_dev *loopback_idev =
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in6_dev_get(dev_net(dev)->loopback_dev);
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BUG_ON(!loopback_idev);
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do {
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in6_dev_put(xdst->u.rt6.rt6i_idev);
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xdst->u.rt6.rt6i_idev = loopback_idev;
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in6_dev_hold(loopback_idev);
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xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst);
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} while (xdst->u.dst.xfrm);
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__in6_dev_put(loopback_idev);
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}
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xfrm_dst_ifdown(dst, dev);
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}
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static struct dst_ops xfrm6_dst_ops_template = {
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.family = AF_INET6,
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.update_pmtu = xfrm6_update_pmtu,
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.redirect = xfrm6_redirect,
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.cow_metrics = dst_cow_metrics_generic,
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.destroy = xfrm6_dst_destroy,
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.ifdown = xfrm6_dst_ifdown,
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.local_out = __ip6_local_out,
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.gc_thresh = 32768,
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};
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static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
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.dst_ops = &xfrm6_dst_ops_template,
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.dst_lookup = xfrm6_dst_lookup,
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.get_saddr = xfrm6_get_saddr,
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.decode_session = _decode_session6,
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.get_tos = xfrm6_get_tos,
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.init_path = xfrm6_init_path,
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.fill_dst = xfrm6_fill_dst,
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.blackhole_route = ip6_blackhole_route,
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};
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static int __init xfrm6_policy_init(void)
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{
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return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
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}
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static void xfrm6_policy_fini(void)
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{
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xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
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}
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#ifdef CONFIG_SYSCTL
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static struct ctl_table xfrm6_policy_table[] = {
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{
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.procname = "xfrm6_gc_thresh",
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.data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{ }
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};
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static int __net_init xfrm6_net_sysctl_init(struct net *net)
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{
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struct ctl_table *table;
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struct ctl_table_header *hdr;
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table = xfrm6_policy_table;
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if (!net_eq(net, &init_net)) {
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table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
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if (!table)
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goto err_alloc;
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table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
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}
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hdr = register_net_sysctl(net, "net/ipv6", table);
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if (!hdr)
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goto err_reg;
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net->ipv6.sysctl.xfrm6_hdr = hdr;
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return 0;
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err_reg:
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if (!net_eq(net, &init_net))
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kfree(table);
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err_alloc:
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return -ENOMEM;
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}
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static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
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{
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struct ctl_table *table;
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if (!net->ipv6.sysctl.xfrm6_hdr)
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return;
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table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
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unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
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if (!net_eq(net, &init_net))
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kfree(table);
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}
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#else /* CONFIG_SYSCTL */
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static inline int xfrm6_net_sysctl_init(struct net *net)
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{
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return 0;
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}
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static inline void xfrm6_net_sysctl_exit(struct net *net)
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{
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}
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#endif
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static int __net_init xfrm6_net_init(struct net *net)
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{
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int ret;
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memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
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sizeof(xfrm6_dst_ops_template));
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ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
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if (ret)
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return ret;
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ret = xfrm6_net_sysctl_init(net);
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if (ret)
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dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
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return ret;
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}
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static void __net_exit xfrm6_net_exit(struct net *net)
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{
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xfrm6_net_sysctl_exit(net);
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dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
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}
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static struct pernet_operations xfrm6_net_ops = {
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.init = xfrm6_net_init,
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.exit = xfrm6_net_exit,
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};
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int __init xfrm6_init(void)
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{
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int ret;
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ret = xfrm6_policy_init();
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if (ret)
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goto out;
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ret = xfrm6_state_init();
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if (ret)
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goto out_policy;
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ret = xfrm6_protocol_init();
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if (ret)
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goto out_state;
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register_pernet_subsys(&xfrm6_net_ops);
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out:
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return ret;
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out_state:
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xfrm6_state_fini();
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out_policy:
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xfrm6_policy_fini();
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goto out;
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}
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void xfrm6_fini(void)
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{
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unregister_pernet_subsys(&xfrm6_net_ops);
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xfrm6_protocol_fini();
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xfrm6_policy_fini();
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xfrm6_state_fini();
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}
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