304 lines
7.1 KiB
C
304 lines
7.1 KiB
C
/*
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* xfrm4_policy.c
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*
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* Changes:
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* Kazunori MIYAZAWA @USAGI
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* YOSHIFUJI Hideaki @USAGI
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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/inetdevice.h>
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#include <linux/if_tunnel.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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static struct xfrm_policy_afinfo xfrm4_policy_afinfo;
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static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
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int tos,
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const xfrm_address_t *saddr,
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const xfrm_address_t *daddr)
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{
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struct rtable *rt;
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memset(fl4, 0, sizeof(*fl4));
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fl4->daddr = daddr->a4;
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fl4->flowi4_tos = tos;
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if (saddr)
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fl4->saddr = saddr->a4;
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rt = __ip_route_output_key(net, fl4);
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if (!IS_ERR(rt))
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return &rt->dst;
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return ERR_CAST(rt);
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}
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static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos,
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const xfrm_address_t *saddr,
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const xfrm_address_t *daddr)
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{
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struct flowi4 fl4;
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return __xfrm4_dst_lookup(net, &fl4, tos, saddr, daddr);
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}
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static int xfrm4_get_saddr(struct net *net,
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xfrm_address_t *saddr, xfrm_address_t *daddr)
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{
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struct dst_entry *dst;
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struct flowi4 fl4;
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dst = __xfrm4_dst_lookup(net, &fl4, 0, NULL, daddr);
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if (IS_ERR(dst))
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return -EHOSTUNREACH;
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saddr->a4 = fl4.saddr;
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dst_release(dst);
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return 0;
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}
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static int xfrm4_get_tos(const struct flowi *fl)
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{
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return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */
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}
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static int xfrm4_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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return 0;
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}
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static int xfrm4_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 rtable *rt = (struct rtable *)xdst->route;
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const struct flowi4 *fl4 = &fl->u.ip4;
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xdst->u.rt.rt_iif = fl4->flowi4_iif;
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xdst->u.dst.dev = dev;
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dev_hold(dev);
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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.rt.rt_is_input = rt->rt_is_input;
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xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
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RTCF_LOCAL);
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xdst->u.rt.rt_type = rt->rt_type;
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xdst->u.rt.rt_gateway = rt->rt_gateway;
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xdst->u.rt.rt_pmtu = rt->rt_pmtu;
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INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
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return 0;
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}
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static void
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_decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
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{
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const struct iphdr *iph = ip_hdr(skb);
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u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
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struct flowi4 *fl4 = &fl->u.ip4;
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memset(fl4, 0, sizeof(struct flowi4));
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fl4->flowi4_mark = skb->mark;
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if (!ip_is_fragment(iph)) {
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switch (iph->protocol) {
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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 (xprth + 4 < skb->data ||
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pskb_may_pull(skb, xprth + 4 - skb->data)) {
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__be16 *ports = (__be16 *)xprth;
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fl4->fl4_sport = ports[!!reverse];
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fl4->fl4_dport = ports[!reverse];
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}
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break;
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case IPPROTO_ICMP:
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if (pskb_may_pull(skb, xprth + 2 - skb->data)) {
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u8 *icmp = xprth;
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fl4->fl4_icmp_type = icmp[0];
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fl4->fl4_icmp_code = icmp[1];
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}
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break;
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case IPPROTO_ESP:
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if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
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__be32 *ehdr = (__be32 *)xprth;
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fl4->fl4_ipsec_spi = ehdr[0];
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}
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break;
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case IPPROTO_AH:
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if (pskb_may_pull(skb, xprth + 8 - skb->data)) {
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__be32 *ah_hdr = (__be32 *)xprth;
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fl4->fl4_ipsec_spi = ah_hdr[1];
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}
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break;
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case IPPROTO_COMP:
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if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
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__be16 *ipcomp_hdr = (__be16 *)xprth;
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fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1]));
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}
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break;
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case IPPROTO_GRE:
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if (pskb_may_pull(skb, xprth + 12 - skb->data)) {
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__be16 *greflags = (__be16 *)xprth;
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__be32 *gre_hdr = (__be32 *)xprth;
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if (greflags[0] & GRE_KEY) {
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if (greflags[0] & GRE_CSUM)
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gre_hdr++;
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fl4->fl4_gre_key = gre_hdr[1];
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}
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}
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break;
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default:
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fl4->fl4_ipsec_spi = 0;
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break;
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}
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}
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fl4->flowi4_proto = iph->protocol;
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fl4->daddr = reverse ? iph->saddr : iph->daddr;
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fl4->saddr = reverse ? iph->daddr : iph->saddr;
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fl4->flowi4_tos = iph->tos;
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}
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static inline int xfrm4_garbage_collect(struct dst_ops *ops)
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{
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struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops);
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xfrm4_policy_afinfo.garbage_collect(net);
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return (dst_entries_get_slow(ops) > ops->gc_thresh * 2);
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}
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static void xfrm4_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 xfrm4_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 xfrm4_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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dst_destroy_metrics_generic(dst);
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xfrm_dst_destroy(xdst);
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}
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static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
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int unregister)
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{
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if (!unregister)
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return;
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xfrm_dst_ifdown(dst, dev);
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}
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static struct dst_ops xfrm4_dst_ops = {
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.family = AF_INET,
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.protocol = cpu_to_be16(ETH_P_IP),
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.gc = xfrm4_garbage_collect,
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.update_pmtu = xfrm4_update_pmtu,
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.redirect = xfrm4_redirect,
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.cow_metrics = dst_cow_metrics_generic,
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.destroy = xfrm4_dst_destroy,
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.ifdown = xfrm4_dst_ifdown,
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.local_out = __ip_local_out,
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.gc_thresh = 1024,
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};
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static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
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.family = AF_INET,
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.dst_ops = &xfrm4_dst_ops,
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.dst_lookup = xfrm4_dst_lookup,
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.get_saddr = xfrm4_get_saddr,
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.decode_session = _decode_session4,
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.get_tos = xfrm4_get_tos,
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.init_path = xfrm4_init_path,
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.fill_dst = xfrm4_fill_dst,
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.blackhole_route = ipv4_blackhole_route,
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};
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#ifdef CONFIG_SYSCTL
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static struct ctl_table xfrm4_policy_table[] = {
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{
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.procname = "xfrm4_gc_thresh",
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.data = &init_net.xfrm.xfrm4_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 struct ctl_table_header *sysctl_hdr;
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#endif
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static void __init xfrm4_policy_init(void)
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{
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xfrm_policy_register_afinfo(&xfrm4_policy_afinfo);
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}
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static void __exit xfrm4_policy_fini(void)
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{
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#ifdef CONFIG_SYSCTL
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if (sysctl_hdr)
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unregister_net_sysctl_table(sysctl_hdr);
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#endif
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xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
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}
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void __init xfrm4_init(int rt_max_size)
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{
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/*
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* Select a default value for the gc_thresh based on the main route
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* table hash size. It seems to me the worst case scenario is when
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* we have ipsec operating in transport mode, in which we create a
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* dst_entry per socket. The xfrm gc algorithm starts trying to remove
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* entries at gc_thresh, and prevents new allocations as 2*gc_thresh
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* so lets set an initial xfrm gc_thresh value at the rt_max_size/2.
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* That will let us store an ipsec connection per route table entry,
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* and start cleaning when were 1/2 full
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*/
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xfrm4_dst_ops.gc_thresh = rt_max_size/2;
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dst_entries_init(&xfrm4_dst_ops);
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xfrm4_state_init();
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xfrm4_policy_init();
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#ifdef CONFIG_SYSCTL
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sysctl_hdr = register_net_sysctl(&init_net, "net/ipv4",
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xfrm4_policy_table);
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#endif
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}
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