![Steven Whitehouse](/assets/img/avatar_default.png)
As per Robert Olsson's patch for ipv4, this is the DECnet version to keep the code "in step". It changes the list of rules to use RCU rather than an rwlock. Inspired-by: Robert Olsson <robert.olsson@its.uu.se> Signed-off-by: Steven Whitehouse <steve@chygwyn.com> Signed-off-by: Patrick Caulfield <patrick@tykepenguin.com> Signed-off-by: David S. Miller <davem@davemloft.net>
427 lines
10 KiB
C
427 lines
10 KiB
C
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/*
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* DECnet An implementation of the DECnet protocol suite for the LINUX
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* operating system. DECnet is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* DECnet Routing Forwarding Information Base (Rules)
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*
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* Author: Steve Whitehouse <SteveW@ACM.org>
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* Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
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*
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*
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* Changes:
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*
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*/
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#include <linux/config.h>
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#include <linux/string.h>
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#include <linux/net.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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#include <linux/proc_fs.h>
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#include <linux/netdevice.h>
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#include <linux/timer.h>
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#include <linux/spinlock.h>
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#include <linux/in_route.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <asm/atomic.h>
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#include <asm/uaccess.h>
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#include <net/neighbour.h>
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#include <net/dst.h>
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#include <net/flow.h>
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#include <net/dn.h>
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#include <net/dn_fib.h>
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#include <net/dn_neigh.h>
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#include <net/dn_dev.h>
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struct dn_fib_rule
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{
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struct hlist_node r_hlist;
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atomic_t r_clntref;
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u32 r_preference;
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unsigned char r_table;
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unsigned char r_action;
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unsigned char r_dst_len;
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unsigned char r_src_len;
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__le16 r_src;
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__le16 r_srcmask;
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__le16 r_dst;
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__le16 r_dstmask;
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__le16 r_srcmap;
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u8 r_flags;
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#ifdef CONFIG_DECNET_ROUTE_FWMARK
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u32 r_fwmark;
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#endif
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int r_ifindex;
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char r_ifname[IFNAMSIZ];
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int r_dead;
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struct rcu_head rcu;
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};
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static struct dn_fib_rule default_rule = {
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.r_clntref = ATOMIC_INIT(2),
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.r_preference = 0x7fff,
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.r_table = RT_TABLE_MAIN,
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.r_action = RTN_UNICAST
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};
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static struct hlist_head dn_fib_rules;
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int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
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{
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struct rtattr **rta = arg;
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struct rtmsg *rtm = NLMSG_DATA(nlh);
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struct dn_fib_rule *r;
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struct hlist_node *node;
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int err = -ESRCH;
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hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
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if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
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rtm->rtm_src_len == r->r_src_len &&
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rtm->rtm_dst_len == r->r_dst_len &&
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(!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 2) == 0) &&
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#ifdef CONFIG_DECNET_ROUTE_FWMARK
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(!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
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#endif
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(!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
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(!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
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(!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) &&
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(!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
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err = -EPERM;
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if (r == &default_rule)
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break;
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hlist_del_rcu(&r->r_hlist);
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r->r_dead = 1;
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dn_fib_rule_put(r);
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err = 0;
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break;
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}
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}
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return err;
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}
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static inline void dn_fib_rule_put_rcu(struct rcu_head *head)
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{
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struct dn_fib_rule *r = container_of(head, struct dn_fib_rule, rcu);
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kfree(r);
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}
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void dn_fib_rule_put(struct dn_fib_rule *r)
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{
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if (atomic_dec_and_test(&r->r_clntref)) {
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if (r->r_dead)
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call_rcu(&r->rcu, dn_fib_rule_put_rcu);
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else
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printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
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}
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}
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int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
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{
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struct rtattr **rta = arg;
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struct rtmsg *rtm = NLMSG_DATA(nlh);
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struct dn_fib_rule *r, *new_r, *last = NULL;
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struct hlist_node *node = NULL;
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unsigned char table_id;
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if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
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return -EINVAL;
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if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
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return -EINVAL;
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if (rtm->rtm_type == RTN_NAT)
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return -EINVAL;
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table_id = rtm->rtm_table;
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if (table_id == RT_TABLE_UNSPEC) {
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struct dn_fib_table *tb;
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if (rtm->rtm_type == RTN_UNICAST) {
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if ((tb = dn_fib_empty_table()) == NULL)
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return -ENOBUFS;
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table_id = tb->n;
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}
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}
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new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
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if (!new_r)
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return -ENOMEM;
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memset(new_r, 0, sizeof(*new_r));
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if (rta[RTA_SRC-1])
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memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
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if (rta[RTA_DST-1])
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memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);
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if (rta[RTA_GATEWAY-1])
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memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 2);
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new_r->r_src_len = rtm->rtm_src_len;
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new_r->r_dst_len = rtm->rtm_dst_len;
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new_r->r_srcmask = dnet_make_mask(rtm->rtm_src_len);
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new_r->r_dstmask = dnet_make_mask(rtm->rtm_dst_len);
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#ifdef CONFIG_DECNET_ROUTE_FWMARK
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if (rta[RTA_PROTOINFO-1])
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memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
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#endif
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new_r->r_action = rtm->rtm_type;
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new_r->r_flags = rtm->rtm_flags;
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if (rta[RTA_PRIORITY-1])
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memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
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new_r->r_table = table_id;
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if (rta[RTA_IIF-1]) {
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struct net_device *dev;
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rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ);
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new_r->r_ifindex = -1;
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dev = dev_get_by_name(new_r->r_ifname);
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if (dev) {
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new_r->r_ifindex = dev->ifindex;
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dev_put(dev);
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}
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}
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r = container_of(dn_fib_rules.first, struct dn_fib_rule, r_hlist);
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if (!new_r->r_preference) {
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if (r && r->r_hlist.next != NULL) {
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r = container_of(r->r_hlist.next, struct dn_fib_rule, r_hlist);
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if (r->r_preference)
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new_r->r_preference = r->r_preference - 1;
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}
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}
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hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
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if (r->r_preference > new_r->r_preference)
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break;
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last = r;
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}
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atomic_inc(&new_r->r_clntref);
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if (last)
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hlist_add_after_rcu(&last->r_hlist, &new_r->r_hlist);
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else
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hlist_add_before_rcu(&new_r->r_hlist, &r->r_hlist);
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return 0;
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}
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int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
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{
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struct dn_fib_rule *r, *policy;
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struct dn_fib_table *tb;
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__le16 saddr = flp->fld_src;
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__le16 daddr = flp->fld_dst;
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struct hlist_node *node;
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int err;
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rcu_read_lock();
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hlist_for_each_entry_rcu(r, node, &dn_fib_rules, r_hlist) {
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if (((saddr^r->r_src) & r->r_srcmask) ||
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((daddr^r->r_dst) & r->r_dstmask) ||
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#ifdef CONFIG_DECNET_ROUTE_FWMARK
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(r->r_fwmark && r->r_fwmark != flp->fld_fwmark) ||
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#endif
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(r->r_ifindex && r->r_ifindex != flp->iif))
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continue;
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switch(r->r_action) {
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case RTN_UNICAST:
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case RTN_NAT:
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policy = r;
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break;
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case RTN_UNREACHABLE:
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rcu_read_unlock();
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return -ENETUNREACH;
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default:
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case RTN_BLACKHOLE:
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rcu_read_unlock();
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return -EINVAL;
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case RTN_PROHIBIT:
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rcu_read_unlock();
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return -EACCES;
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}
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if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)
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continue;
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err = tb->lookup(tb, flp, res);
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if (err == 0) {
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res->r = policy;
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if (policy)
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atomic_inc(&policy->r_clntref);
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rcu_read_unlock();
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return 0;
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}
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if (err < 0 && err != -EAGAIN) {
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rcu_read_unlock();
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return err;
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}
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}
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rcu_read_unlock();
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return -ESRCH;
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}
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unsigned dnet_addr_type(__le16 addr)
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{
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struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
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struct dn_fib_res res;
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unsigned ret = RTN_UNICAST;
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struct dn_fib_table *tb = dn_fib_tables[RT_TABLE_LOCAL];
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res.r = NULL;
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if (tb) {
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if (!tb->lookup(tb, &fl, &res)) {
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ret = res.type;
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dn_fib_res_put(&res);
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}
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}
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return ret;
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}
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__le16 dn_fib_rules_policy(__le16 saddr, struct dn_fib_res *res, unsigned *flags)
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{
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struct dn_fib_rule *r = res->r;
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if (r->r_action == RTN_NAT) {
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int addrtype = dnet_addr_type(r->r_srcmap);
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if (addrtype == RTN_NAT) {
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saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
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*flags |= RTCF_SNAT;
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} else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
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saddr = r->r_srcmap;
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*flags |= RTCF_MASQ;
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}
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}
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return saddr;
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}
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static void dn_fib_rules_detach(struct net_device *dev)
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{
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struct hlist_node *node;
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struct dn_fib_rule *r;
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hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
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if (r->r_ifindex == dev->ifindex)
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r->r_ifindex = -1;
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}
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}
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static void dn_fib_rules_attach(struct net_device *dev)
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{
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struct hlist_node *node;
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struct dn_fib_rule *r;
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hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
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if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)
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r->r_ifindex = dev->ifindex;
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}
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}
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static int dn_fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
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{
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struct net_device *dev = ptr;
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switch(event) {
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case NETDEV_UNREGISTER:
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dn_fib_rules_detach(dev);
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dn_fib_sync_down(0, dev, 1);
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case NETDEV_REGISTER:
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dn_fib_rules_attach(dev);
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dn_fib_sync_up(dev);
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block dn_fib_rules_notifier = {
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.notifier_call = dn_fib_rules_event,
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};
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static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_fib_rule *r,
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struct netlink_callback *cb, unsigned int flags)
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{
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struct rtmsg *rtm;
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struct nlmsghdr *nlh;
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unsigned char *b = skb->tail;
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nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWRULE, sizeof(*rtm), flags);
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rtm = NLMSG_DATA(nlh);
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rtm->rtm_family = AF_DECnet;
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rtm->rtm_dst_len = r->r_dst_len;
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rtm->rtm_src_len = r->r_src_len;
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rtm->rtm_tos = 0;
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#ifdef CONFIG_DECNET_ROUTE_FWMARK
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if (r->r_fwmark)
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RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
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#endif
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rtm->rtm_table = r->r_table;
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rtm->rtm_protocol = 0;
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rtm->rtm_scope = 0;
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rtm->rtm_type = r->r_action;
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rtm->rtm_flags = r->r_flags;
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if (r->r_dst_len)
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RTA_PUT(skb, RTA_DST, 2, &r->r_dst);
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if (r->r_src_len)
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RTA_PUT(skb, RTA_SRC, 2, &r->r_src);
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if (r->r_ifname[0])
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RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
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if (r->r_preference)
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RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
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if (r->r_srcmap)
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RTA_PUT(skb, RTA_GATEWAY, 2, &r->r_srcmap);
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nlh->nlmsg_len = skb->tail - b;
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return skb->len;
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nlmsg_failure:
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rtattr_failure:
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skb_trim(skb, b - skb->data);
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return -1;
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}
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int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
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{
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int idx = 0;
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int s_idx = cb->args[0];
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struct dn_fib_rule *r;
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struct hlist_node *node;
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rcu_read_lock();
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hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
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if (idx < s_idx)
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continue;
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if (dn_fib_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
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break;
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idx++;
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}
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rcu_read_unlock();
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cb->args[0] = idx;
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return skb->len;
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}
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void __init dn_fib_rules_init(void)
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{
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INIT_HLIST_HEAD(&dn_fib_rules);
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hlist_add_head(&default_rule.r_hlist, &dn_fib_rules);
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register_netdevice_notifier(&dn_fib_rules_notifier);
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}
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void __exit dn_fib_rules_cleanup(void)
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{
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unregister_netdevice_notifier(&dn_fib_rules_notifier);
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}
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