mirror of https://github.com/hak5/openwrt-owl.git
404 lines
10 KiB
Diff
404 lines
10 KiB
Diff
From: Alexander Duyck <alexander.h.duyck@redhat.com>
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Date: Wed, 31 Dec 2014 10:56:24 -0800
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Subject: [PATCH] fib_trie: Push rcu_read_lock/unlock to callers
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This change is to start cleaning up some of the rcu_read_lock/unlock
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handling. I realized while reviewing the code there are several spots that
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I don't believe are being handled correctly or are masking warnings by
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locally calling rcu_read_lock/unlock instead of calling them at the correct
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level.
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A common example is a call to fib_get_table followed by fib_table_lookup.
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The rcu_read_lock/unlock ought to wrap both but there are several spots where
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they were not wrapped.
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Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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--- a/include/net/ip_fib.h
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+++ b/include/net/ip_fib.h
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@@ -222,16 +222,19 @@ static inline struct fib_table *fib_new_
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static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
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struct fib_result *res)
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{
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- struct fib_table *table;
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+ int err = -ENETUNREACH;
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- table = fib_get_table(net, RT_TABLE_LOCAL);
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- if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
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- return 0;
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-
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- table = fib_get_table(net, RT_TABLE_MAIN);
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- if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
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- return 0;
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- return -ENETUNREACH;
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+ rcu_read_lock();
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+
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+ if (!fib_table_lookup(fib_get_table(net, RT_TABLE_LOCAL), flp, res,
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+ FIB_LOOKUP_NOREF) ||
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+ !fib_table_lookup(fib_get_table(net, RT_TABLE_MAIN), flp, res,
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+ FIB_LOOKUP_NOREF))
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+ err = 0;
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+
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+ rcu_read_unlock();
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+
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+ return err;
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}
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#else /* CONFIG_IP_MULTIPLE_TABLES */
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@@ -247,20 +250,25 @@ static inline int fib_lookup(struct net
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struct fib_result *res)
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{
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if (!net->ipv4.fib_has_custom_rules) {
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+ int err = -ENETUNREACH;
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+
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+ rcu_read_lock();
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+
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res->tclassid = 0;
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- if (net->ipv4.fib_local &&
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- !fib_table_lookup(net->ipv4.fib_local, flp, res,
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- FIB_LOOKUP_NOREF))
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- return 0;
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- if (net->ipv4.fib_main &&
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- !fib_table_lookup(net->ipv4.fib_main, flp, res,
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- FIB_LOOKUP_NOREF))
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- return 0;
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- if (net->ipv4.fib_default &&
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- !fib_table_lookup(net->ipv4.fib_default, flp, res,
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- FIB_LOOKUP_NOREF))
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- return 0;
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- return -ENETUNREACH;
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+ if ((net->ipv4.fib_local &&
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+ !fib_table_lookup(net->ipv4.fib_local, flp, res,
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+ FIB_LOOKUP_NOREF)) ||
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+ (net->ipv4.fib_main &&
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+ !fib_table_lookup(net->ipv4.fib_main, flp, res,
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+ FIB_LOOKUP_NOREF)) ||
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+ (net->ipv4.fib_default &&
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+ !fib_table_lookup(net->ipv4.fib_default, flp, res,
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+ FIB_LOOKUP_NOREF)))
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+ err = 0;
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+
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+ rcu_read_unlock();
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+
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+ return err;
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}
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return __fib_lookup(net, flp, res);
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}
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--- a/net/ipv4/fib_frontend.c
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+++ b/net/ipv4/fib_frontend.c
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@@ -109,6 +109,7 @@ struct fib_table *fib_new_table(struct n
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return tb;
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}
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+/* caller must hold either rtnl or rcu read lock */
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struct fib_table *fib_get_table(struct net *net, u32 id)
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{
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struct fib_table *tb;
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@@ -119,15 +120,11 @@ struct fib_table *fib_get_table(struct n
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id = RT_TABLE_MAIN;
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h = id & (FIB_TABLE_HASHSZ - 1);
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- rcu_read_lock();
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head = &net->ipv4.fib_table_hash[h];
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hlist_for_each_entry_rcu(tb, head, tb_hlist) {
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- if (tb->tb_id == id) {
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- rcu_read_unlock();
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+ if (tb->tb_id == id)
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return tb;
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- }
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}
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- rcu_read_unlock();
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return NULL;
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}
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#endif /* CONFIG_IP_MULTIPLE_TABLES */
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@@ -167,16 +164,18 @@ static inline unsigned int __inet_dev_ad
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if (ipv4_is_multicast(addr))
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return RTN_MULTICAST;
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+ rcu_read_lock();
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+
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local_table = fib_get_table(net, RT_TABLE_LOCAL);
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if (local_table) {
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ret = RTN_UNICAST;
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- rcu_read_lock();
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if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {
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if (!dev || dev == res.fi->fib_dev)
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ret = res.type;
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}
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- rcu_read_unlock();
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}
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+
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+ rcu_read_unlock();
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return ret;
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}
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@@ -923,7 +922,7 @@ no_promotions:
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#undef BRD1_OK
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}
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-static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
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+static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
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{
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struct fib_result res;
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@@ -933,6 +932,11 @@ static void nl_fib_lookup(struct fib_res
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.flowi4_tos = frn->fl_tos,
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.flowi4_scope = frn->fl_scope,
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};
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+ struct fib_table *tb;
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+
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+ rcu_read_lock();
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+
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+ tb = fib_get_table(net, frn->tb_id_in);
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frn->err = -ENOENT;
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if (tb) {
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@@ -949,6 +953,8 @@ static void nl_fib_lookup(struct fib_res
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}
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local_bh_enable();
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}
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+
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+ rcu_read_unlock();
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}
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static void nl_fib_input(struct sk_buff *skb)
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@@ -956,7 +962,6 @@ static void nl_fib_input(struct sk_buff
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struct net *net;
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struct fib_result_nl *frn;
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struct nlmsghdr *nlh;
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- struct fib_table *tb;
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u32 portid;
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net = sock_net(skb->sk);
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@@ -971,9 +976,7 @@ static void nl_fib_input(struct sk_buff
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nlh = nlmsg_hdr(skb);
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frn = (struct fib_result_nl *) nlmsg_data(nlh);
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- tb = fib_get_table(net, frn->tb_id_in);
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-
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- nl_fib_lookup(frn, tb);
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+ nl_fib_lookup(net, frn);
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portid = NETLINK_CB(skb).portid; /* netlink portid */
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NETLINK_CB(skb).portid = 0; /* from kernel */
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--- a/net/ipv4/fib_rules.c
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+++ b/net/ipv4/fib_rules.c
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@@ -81,27 +81,25 @@ static int fib4_rule_action(struct fib_r
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break;
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case FR_ACT_UNREACHABLE:
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- err = -ENETUNREACH;
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- goto errout;
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+ return -ENETUNREACH;
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case FR_ACT_PROHIBIT:
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- err = -EACCES;
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- goto errout;
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+ return -EACCES;
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case FR_ACT_BLACKHOLE:
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default:
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- err = -EINVAL;
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- goto errout;
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+ return -EINVAL;
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}
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+ rcu_read_lock();
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+
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tbl = fib_get_table(rule->fr_net, rule->table);
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- if (!tbl)
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- goto errout;
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+ if (tbl)
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+ err = fib_table_lookup(tbl, &flp->u.ip4,
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+ (struct fib_result *)arg->result,
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+ arg->flags);
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- err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags);
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- if (err > 0)
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- err = -EAGAIN;
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-errout:
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+ rcu_read_unlock();
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return err;
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}
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--- a/net/ipv4/fib_trie.c
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+++ b/net/ipv4/fib_trie.c
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@@ -1181,72 +1181,6 @@ err:
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return err;
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}
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-/* should be called with rcu_read_lock */
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-static int check_leaf(struct fib_table *tb, struct trie *t, struct tnode *l,
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- t_key key, const struct flowi4 *flp,
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- struct fib_result *res, int fib_flags)
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-{
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- struct leaf_info *li;
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- struct hlist_head *hhead = &l->list;
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-
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- hlist_for_each_entry_rcu(li, hhead, hlist) {
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- struct fib_alias *fa;
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-
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- if (l->key != (key & li->mask_plen))
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- continue;
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-
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- list_for_each_entry_rcu(fa, &li->falh, fa_list) {
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- struct fib_info *fi = fa->fa_info;
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- int nhsel, err;
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-
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- if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
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- continue;
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- if (fi->fib_dead)
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- continue;
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- if (fa->fa_info->fib_scope < flp->flowi4_scope)
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- continue;
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- fib_alias_accessed(fa);
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- err = fib_props[fa->fa_type].error;
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- if (unlikely(err < 0)) {
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-#ifdef CONFIG_IP_FIB_TRIE_STATS
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- this_cpu_inc(t->stats->semantic_match_passed);
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-#endif
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- return err;
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- }
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- if (fi->fib_flags & RTNH_F_DEAD)
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- continue;
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- for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
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- const struct fib_nh *nh = &fi->fib_nh[nhsel];
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-
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- if (nh->nh_flags & RTNH_F_DEAD)
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- continue;
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- if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
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- continue;
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-
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-#ifdef CONFIG_IP_FIB_TRIE_STATS
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- this_cpu_inc(t->stats->semantic_match_passed);
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-#endif
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- res->prefixlen = li->plen;
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- res->nh_sel = nhsel;
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- res->type = fa->fa_type;
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- res->scope = fi->fib_scope;
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- res->fi = fi;
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- res->table = tb;
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- res->fa_head = &li->falh;
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- if (!(fib_flags & FIB_LOOKUP_NOREF))
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- atomic_inc(&fi->fib_clntref);
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- return 0;
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- }
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- }
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-
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-#ifdef CONFIG_IP_FIB_TRIE_STATS
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- this_cpu_inc(t->stats->semantic_match_miss);
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-#endif
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- }
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-
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- return 1;
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-}
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-
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static inline t_key prefix_mismatch(t_key key, struct tnode *n)
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{
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t_key prefix = n->key;
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@@ -1254,6 +1188,7 @@ static inline t_key prefix_mismatch(t_ke
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return (key ^ prefix) & (prefix | -prefix);
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}
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+/* should be called with rcu_read_lock */
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int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
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struct fib_result *res, int fib_flags)
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{
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@@ -1263,14 +1198,12 @@ int fib_table_lookup(struct fib_table *t
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#endif
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const t_key key = ntohl(flp->daddr);
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struct tnode *n, *pn;
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+ struct leaf_info *li;
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t_key cindex;
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- int ret = 1;
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-
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- rcu_read_lock();
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n = rcu_dereference(t->trie);
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if (!n)
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- goto failed;
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+ return -EAGAIN;
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#ifdef CONFIG_IP_FIB_TRIE_STATS
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this_cpu_inc(stats->gets);
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@@ -1350,7 +1283,7 @@ backtrace:
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pn = node_parent_rcu(pn);
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if (unlikely(!pn))
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- goto failed;
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+ return -EAGAIN;
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#ifdef CONFIG_IP_FIB_TRIE_STATS
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this_cpu_inc(stats->backtrack);
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#endif
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@@ -1368,12 +1301,62 @@ backtrace:
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found:
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/* Step 3: Process the leaf, if that fails fall back to backtracing */
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- ret = check_leaf(tb, t, n, key, flp, res, fib_flags);
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- if (unlikely(ret > 0))
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- goto backtrace;
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-failed:
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- rcu_read_unlock();
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- return ret;
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+ hlist_for_each_entry_rcu(li, &n->list, hlist) {
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+ struct fib_alias *fa;
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+
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+ if ((key ^ n->key) & li->mask_plen)
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+ continue;
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+
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+ list_for_each_entry_rcu(fa, &li->falh, fa_list) {
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+ struct fib_info *fi = fa->fa_info;
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+ int nhsel, err;
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+
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+ if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
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+ continue;
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+ if (fi->fib_dead)
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+ continue;
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+ if (fa->fa_info->fib_scope < flp->flowi4_scope)
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+ continue;
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+ fib_alias_accessed(fa);
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+ err = fib_props[fa->fa_type].error;
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+ if (unlikely(err < 0)) {
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+#ifdef CONFIG_IP_FIB_TRIE_STATS
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+ this_cpu_inc(stats->semantic_match_passed);
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+#endif
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+ return err;
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+ }
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+ if (fi->fib_flags & RTNH_F_DEAD)
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+ continue;
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+ for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
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+ const struct fib_nh *nh = &fi->fib_nh[nhsel];
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+
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+ if (nh->nh_flags & RTNH_F_DEAD)
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+ continue;
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+ if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
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+ continue;
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+
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+ if (!(fib_flags & FIB_LOOKUP_NOREF))
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+ atomic_inc(&fi->fib_clntref);
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+
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+ res->prefixlen = li->plen;
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+ res->nh_sel = nhsel;
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+ res->type = fa->fa_type;
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+ res->scope = fi->fib_scope;
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+ res->fi = fi;
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+ res->table = tb;
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+ res->fa_head = &li->falh;
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+#ifdef CONFIG_IP_FIB_TRIE_STATS
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+ this_cpu_inc(stats->semantic_match_passed);
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+#endif
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+ return err;
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+ }
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+ }
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+
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+#ifdef CONFIG_IP_FIB_TRIE_STATS
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+ this_cpu_inc(stats->semantic_match_miss);
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+#endif
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+ }
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+ goto backtrace;
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}
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EXPORT_SYMBOL_GPL(fib_table_lookup);
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