474 lines
9.8 KiB
C
474 lines
9.8 KiB
C
/*
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* net/core/fib_rules.c Generic Routing Rules
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2.
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <net/fib_rules.h>
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static LIST_HEAD(rules_ops);
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static DEFINE_SPINLOCK(rules_mod_lock);
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static void notify_rule_change(int event, struct fib_rule *rule,
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struct fib_rules_ops *ops, struct nlmsghdr *nlh,
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u32 pid);
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static struct fib_rules_ops *lookup_rules_ops(int family)
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{
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struct fib_rules_ops *ops;
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rcu_read_lock();
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list_for_each_entry_rcu(ops, &rules_ops, list) {
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if (ops->family == family) {
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if (!try_module_get(ops->owner))
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ops = NULL;
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rcu_read_unlock();
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return ops;
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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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static void rules_ops_put(struct fib_rules_ops *ops)
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{
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if (ops)
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module_put(ops->owner);
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}
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int fib_rules_register(struct fib_rules_ops *ops)
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{
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int err = -EEXIST;
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struct fib_rules_ops *o;
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if (ops->rule_size < sizeof(struct fib_rule))
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return -EINVAL;
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if (ops->match == NULL || ops->configure == NULL ||
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ops->compare == NULL || ops->fill == NULL ||
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ops->action == NULL)
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return -EINVAL;
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spin_lock(&rules_mod_lock);
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list_for_each_entry(o, &rules_ops, list)
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if (ops->family == o->family)
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goto errout;
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list_add_tail_rcu(&ops->list, &rules_ops);
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err = 0;
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errout:
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spin_unlock(&rules_mod_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(fib_rules_register);
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static void cleanup_ops(struct fib_rules_ops *ops)
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{
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struct fib_rule *rule, *tmp;
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list_for_each_entry_safe(rule, tmp, ops->rules_list, list) {
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list_del_rcu(&rule->list);
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fib_rule_put(rule);
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}
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}
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int fib_rules_unregister(struct fib_rules_ops *ops)
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{
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int err = 0;
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struct fib_rules_ops *o;
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spin_lock(&rules_mod_lock);
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list_for_each_entry(o, &rules_ops, list) {
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if (o == ops) {
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list_del_rcu(&o->list);
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cleanup_ops(ops);
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goto out;
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}
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}
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err = -ENOENT;
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out:
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spin_unlock(&rules_mod_lock);
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synchronize_rcu();
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return err;
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}
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EXPORT_SYMBOL_GPL(fib_rules_unregister);
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static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
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struct flowi *fl, int flags)
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{
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int ret = 0;
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if (rule->ifindex && (rule->ifindex != fl->iif))
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goto out;
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if ((rule->mark ^ fl->mark) & rule->mark_mask)
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goto out;
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ret = ops->match(rule, fl, flags);
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out:
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return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
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}
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int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
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int flags, struct fib_lookup_arg *arg)
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{
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struct fib_rule *rule;
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int err;
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rcu_read_lock();
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list_for_each_entry_rcu(rule, ops->rules_list, list) {
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if (!fib_rule_match(rule, ops, fl, flags))
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continue;
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err = ops->action(rule, fl, flags, arg);
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if (err != -EAGAIN) {
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fib_rule_get(rule);
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arg->rule = rule;
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goto out;
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}
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}
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err = -ENETUNREACH;
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out:
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rcu_read_unlock();
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return err;
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}
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EXPORT_SYMBOL_GPL(fib_rules_lookup);
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int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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{
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struct fib_rule_hdr *frh = nlmsg_data(nlh);
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struct fib_rules_ops *ops = NULL;
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struct fib_rule *rule, *r, *last = NULL;
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struct nlattr *tb[FRA_MAX+1];
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int err = -EINVAL;
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if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
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goto errout;
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ops = lookup_rules_ops(frh->family);
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if (ops == NULL) {
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err = EAFNOSUPPORT;
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goto errout;
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}
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err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
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if (err < 0)
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goto errout;
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rule = kzalloc(ops->rule_size, GFP_KERNEL);
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if (rule == NULL) {
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err = -ENOMEM;
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goto errout;
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}
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if (tb[FRA_PRIORITY])
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rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
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if (tb[FRA_IFNAME]) {
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struct net_device *dev;
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rule->ifindex = -1;
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nla_strlcpy(rule->ifname, tb[FRA_IFNAME], IFNAMSIZ);
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dev = __dev_get_by_name(rule->ifname);
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if (dev)
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rule->ifindex = dev->ifindex;
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}
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if (tb[FRA_FWMARK]) {
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rule->mark = nla_get_u32(tb[FRA_FWMARK]);
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if (rule->mark)
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/* compatibility: if the mark value is non-zero all bits
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* are compared unless a mask is explicitly specified.
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*/
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rule->mark_mask = 0xFFFFFFFF;
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}
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if (tb[FRA_FWMASK])
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rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
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rule->action = frh->action;
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rule->flags = frh->flags;
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rule->table = frh_get_table(frh, tb);
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if (!rule->pref && ops->default_pref)
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rule->pref = ops->default_pref();
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err = ops->configure(rule, skb, nlh, frh, tb);
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if (err < 0)
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goto errout_free;
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list_for_each_entry(r, ops->rules_list, list) {
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if (r->pref > rule->pref)
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break;
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last = r;
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}
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fib_rule_get(rule);
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if (last)
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list_add_rcu(&rule->list, &last->list);
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else
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list_add_rcu(&rule->list, ops->rules_list);
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notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
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rules_ops_put(ops);
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return 0;
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errout_free:
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kfree(rule);
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errout:
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rules_ops_put(ops);
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return err;
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}
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int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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{
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struct fib_rule_hdr *frh = nlmsg_data(nlh);
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struct fib_rules_ops *ops = NULL;
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struct fib_rule *rule;
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struct nlattr *tb[FRA_MAX+1];
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int err = -EINVAL;
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if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
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goto errout;
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ops = lookup_rules_ops(frh->family);
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if (ops == NULL) {
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err = EAFNOSUPPORT;
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goto errout;
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}
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err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
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if (err < 0)
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goto errout;
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list_for_each_entry(rule, ops->rules_list, list) {
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if (frh->action && (frh->action != rule->action))
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continue;
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if (frh->table && (frh_get_table(frh, tb) != rule->table))
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continue;
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if (tb[FRA_PRIORITY] &&
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(rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
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continue;
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if (tb[FRA_IFNAME] &&
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nla_strcmp(tb[FRA_IFNAME], rule->ifname))
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continue;
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if (tb[FRA_FWMARK] &&
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(rule->mark != nla_get_u32(tb[FRA_FWMARK])))
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continue;
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if (tb[FRA_FWMASK] &&
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(rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
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continue;
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if (!ops->compare(rule, frh, tb))
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continue;
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if (rule->flags & FIB_RULE_PERMANENT) {
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err = -EPERM;
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goto errout;
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}
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list_del_rcu(&rule->list);
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synchronize_rcu();
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notify_rule_change(RTM_DELRULE, rule, ops, nlh,
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NETLINK_CB(skb).pid);
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fib_rule_put(rule);
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rules_ops_put(ops);
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return 0;
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}
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err = -ENOENT;
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errout:
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rules_ops_put(ops);
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return err;
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}
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static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
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struct fib_rule *rule)
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{
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size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
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+ nla_total_size(IFNAMSIZ) /* FRA_IFNAME */
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+ nla_total_size(4) /* FRA_PRIORITY */
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+ nla_total_size(4) /* FRA_TABLE */
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+ nla_total_size(4) /* FRA_FWMARK */
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+ nla_total_size(4); /* FRA_FWMASK */
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if (ops->nlmsg_payload)
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payload += ops->nlmsg_payload(rule);
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return payload;
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}
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static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
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u32 pid, u32 seq, int type, int flags,
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struct fib_rules_ops *ops)
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{
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struct nlmsghdr *nlh;
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struct fib_rule_hdr *frh;
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nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
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if (nlh == NULL)
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return -1;
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frh = nlmsg_data(nlh);
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frh->table = rule->table;
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NLA_PUT_U32(skb, FRA_TABLE, rule->table);
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frh->res1 = 0;
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frh->res2 = 0;
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frh->action = rule->action;
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frh->flags = rule->flags;
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if (rule->ifname[0])
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NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);
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if (rule->pref)
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NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
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if (rule->mark)
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NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);
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if (rule->mark_mask || rule->mark)
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NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);
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if (ops->fill(rule, skb, nlh, frh) < 0)
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goto nla_put_failure;
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return nlmsg_end(skb, nlh);
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nla_put_failure:
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return nlmsg_cancel(skb, nlh);
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}
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int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family)
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{
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int idx = 0;
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struct fib_rule *rule;
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struct fib_rules_ops *ops;
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ops = lookup_rules_ops(family);
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if (ops == NULL)
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return -EAFNOSUPPORT;
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rcu_read_lock();
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list_for_each_entry(rule, ops->rules_list, list) {
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if (idx < cb->args[0])
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goto skip;
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if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
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cb->nlh->nlmsg_seq, RTM_NEWRULE,
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NLM_F_MULTI, ops) < 0)
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break;
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skip:
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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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rules_ops_put(ops);
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return skb->len;
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}
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EXPORT_SYMBOL_GPL(fib_rules_dump);
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static void notify_rule_change(int event, struct fib_rule *rule,
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struct fib_rules_ops *ops, struct nlmsghdr *nlh,
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u32 pid)
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{
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struct sk_buff *skb;
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int err = -ENOBUFS;
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skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
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if (skb == NULL)
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goto errout;
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err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
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/* failure implies BUG in fib_rule_nlmsg_size() */
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BUG_ON(err < 0);
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err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL);
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errout:
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if (err < 0)
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rtnl_set_sk_err(ops->nlgroup, err);
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}
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static void attach_rules(struct list_head *rules, struct net_device *dev)
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{
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struct fib_rule *rule;
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list_for_each_entry(rule, rules, list) {
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if (rule->ifindex == -1 &&
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strcmp(dev->name, rule->ifname) == 0)
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rule->ifindex = dev->ifindex;
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}
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}
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static void detach_rules(struct list_head *rules, struct net_device *dev)
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{
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struct fib_rule *rule;
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list_for_each_entry(rule, rules, list)
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if (rule->ifindex == dev->ifindex)
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rule->ifindex = -1;
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}
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static int fib_rules_event(struct notifier_block *this, unsigned long event,
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void *ptr)
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{
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struct net_device *dev = ptr;
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struct fib_rules_ops *ops;
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ASSERT_RTNL();
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rcu_read_lock();
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switch (event) {
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case NETDEV_REGISTER:
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list_for_each_entry(ops, &rules_ops, list)
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attach_rules(ops->rules_list, dev);
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break;
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case NETDEV_UNREGISTER:
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list_for_each_entry(ops, &rules_ops, list)
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detach_rules(ops->rules_list, dev);
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break;
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}
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rcu_read_unlock();
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return NOTIFY_DONE;
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}
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static struct notifier_block fib_rules_notifier = {
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.notifier_call = fib_rules_event,
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};
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static int __init fib_rules_init(void)
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{
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return register_netdevice_notifier(&fib_rules_notifier);
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}
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subsys_initcall(fib_rules_init);
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