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7764a45a8f
This change adds a new operation to the fib_rules_ops struct; it allows the suppression of routing decisions if certain criteria are not met by its results. The first implemented constraint is a minimum prefix length added to the structures of routing rules. If a rule is added with a minimum prefix length >0, only routes meeting this threshold will be considered. Any other (more general) routing table entries will be ignored. When configuring a system with multiple network uplinks and default routes, it is often convinient to reference the main routing table multiple times - but omitting the default route. Using this patch and a modified "ip" utility, this can be achieved by using the following command sequence: $ ip route add table secuplink default via 10.42.23.1 $ ip rule add pref 100 table main prefixlength 1 $ ip rule add pref 150 fwmark 0xA table secuplink With this setup, packets marked 0xA will be processed by the additional routing table "secuplink", but only if no suitable route in the main routing table can be found. By using a minimal prefixlength of 1, the default route (/0) of the table "main" is hidden to packets processed by rule 100; packets traveling to destinations with more specific routing entries are processed as usual. Signed-off-by: Stefan Tomanek <stefan.tomanek@wertarbyte.de> Signed-off-by: David S. Miller <davem@davemloft.net>
125 lines
3.2 KiB
C
125 lines
3.2 KiB
C
#ifndef __NET_FIB_RULES_H
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#define __NET_FIB_RULES_H
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/netdevice.h>
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#include <linux/fib_rules.h>
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#include <net/flow.h>
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#include <net/rtnetlink.h>
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struct fib_rule {
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struct list_head list;
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atomic_t refcnt;
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int iifindex;
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int oifindex;
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u32 mark;
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u32 mark_mask;
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u32 pref;
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u32 flags;
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u32 table;
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u8 table_prefixlen_min;
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u8 action;
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u32 target;
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struct fib_rule __rcu *ctarget;
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char iifname[IFNAMSIZ];
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char oifname[IFNAMSIZ];
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struct rcu_head rcu;
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struct net * fr_net;
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};
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struct fib_lookup_arg {
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void *lookup_ptr;
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void *result;
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struct fib_rule *rule;
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int flags;
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#define FIB_LOOKUP_NOREF 1
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};
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struct fib_rules_ops {
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int family;
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struct list_head list;
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int rule_size;
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int addr_size;
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int unresolved_rules;
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int nr_goto_rules;
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int (*action)(struct fib_rule *,
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struct flowi *, int,
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struct fib_lookup_arg *);
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bool (*suppress)(struct fib_rule *,
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struct fib_lookup_arg *);
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int (*match)(struct fib_rule *,
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struct flowi *, int);
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int (*configure)(struct fib_rule *,
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struct sk_buff *,
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struct fib_rule_hdr *,
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struct nlattr **);
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void (*delete)(struct fib_rule *);
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int (*compare)(struct fib_rule *,
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struct fib_rule_hdr *,
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struct nlattr **);
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int (*fill)(struct fib_rule *, struct sk_buff *,
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struct fib_rule_hdr *);
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u32 (*default_pref)(struct fib_rules_ops *ops);
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size_t (*nlmsg_payload)(struct fib_rule *);
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/* Called after modifications to the rules set, must flush
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* the route cache if one exists. */
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void (*flush_cache)(struct fib_rules_ops *ops);
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int nlgroup;
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const struct nla_policy *policy;
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struct list_head rules_list;
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struct module *owner;
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struct net *fro_net;
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struct rcu_head rcu;
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};
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#define FRA_GENERIC_POLICY \
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[FRA_IIFNAME] = { .type = NLA_STRING, .len = IFNAMSIZ - 1 }, \
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[FRA_OIFNAME] = { .type = NLA_STRING, .len = IFNAMSIZ - 1 }, \
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[FRA_PRIORITY] = { .type = NLA_U32 }, \
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[FRA_FWMARK] = { .type = NLA_U32 }, \
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[FRA_FWMASK] = { .type = NLA_U32 }, \
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[FRA_TABLE] = { .type = NLA_U32 }, \
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[FRA_TABLE_PREFIXLEN_MIN] = { .type = NLA_U8 }, \
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[FRA_GOTO] = { .type = NLA_U32 }
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static inline void fib_rule_get(struct fib_rule *rule)
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{
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atomic_inc(&rule->refcnt);
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}
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static inline void fib_rule_put_rcu(struct rcu_head *head)
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{
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struct fib_rule *rule = container_of(head, struct fib_rule, rcu);
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release_net(rule->fr_net);
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kfree(rule);
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}
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static inline void fib_rule_put(struct fib_rule *rule)
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{
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if (atomic_dec_and_test(&rule->refcnt))
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call_rcu(&rule->rcu, fib_rule_put_rcu);
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}
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static inline u32 frh_get_table(struct fib_rule_hdr *frh, struct nlattr **nla)
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{
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if (nla[FRA_TABLE])
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return nla_get_u32(nla[FRA_TABLE]);
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return frh->table;
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}
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extern struct fib_rules_ops *fib_rules_register(const struct fib_rules_ops *, struct net *);
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extern void fib_rules_unregister(struct fib_rules_ops *);
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extern int fib_rules_lookup(struct fib_rules_ops *,
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struct flowi *, int flags,
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struct fib_lookup_arg *);
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extern int fib_default_rule_add(struct fib_rules_ops *,
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u32 pref, u32 table,
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u32 flags);
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extern u32 fib_default_rule_pref(struct fib_rules_ops *ops);
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#endif
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