[NET]: Protocol Independant Policy Routing Rules Framework
Derived from net/ipv/fib_rules.c
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
new file mode 100644
index 0000000..6cdad24
--- /dev/null
+++ b/net/core/fib_rules.c
@@ -0,0 +1,416 @@
+/*
+ * net/core/fib_rules.c Generic Routing Rules
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2.
+ *
+ * Authors: Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <net/fib_rules.h>
+
+static LIST_HEAD(rules_ops);
+static DEFINE_SPINLOCK(rules_mod_lock);
+
+static void notify_rule_change(int event, struct fib_rule *rule,
+ struct fib_rules_ops *ops);
+
+static struct fib_rules_ops *lookup_rules_ops(int family)
+{
+ struct fib_rules_ops *ops;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ops, &rules_ops, list) {
+ if (ops->family == family) {
+ if (!try_module_get(ops->owner))
+ ops = NULL;
+ rcu_read_unlock();
+ return ops;
+ }
+ }
+ rcu_read_unlock();
+
+ return NULL;
+}
+
+static void rules_ops_put(struct fib_rules_ops *ops)
+{
+ if (ops)
+ module_put(ops->owner);
+}
+
+int fib_rules_register(struct fib_rules_ops *ops)
+{
+ int err = -EEXIST;
+ struct fib_rules_ops *o;
+
+ if (ops->rule_size < sizeof(struct fib_rule))
+ return -EINVAL;
+
+ if (ops->match == NULL || ops->configure == NULL ||
+ ops->compare == NULL || ops->fill == NULL ||
+ ops->action == NULL)
+ return -EINVAL;
+
+ spin_lock(&rules_mod_lock);
+ list_for_each_entry(o, &rules_ops, list)
+ if (ops->family == o->family)
+ goto errout;
+
+ list_add_tail_rcu(&ops->list, &rules_ops);
+ err = 0;
+errout:
+ spin_unlock(&rules_mod_lock);
+
+ return err;
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_register);
+
+static void cleanup_ops(struct fib_rules_ops *ops)
+{
+ struct fib_rule *rule, *tmp;
+
+ list_for_each_entry_safe(rule, tmp, ops->rules_list, list) {
+ list_del_rcu(&rule->list);
+ fib_rule_put(rule);
+ }
+}
+
+int fib_rules_unregister(struct fib_rules_ops *ops)
+{
+ int err = 0;
+ struct fib_rules_ops *o;
+
+ spin_lock(&rules_mod_lock);
+ list_for_each_entry(o, &rules_ops, list) {
+ if (o == ops) {
+ list_del_rcu(&o->list);
+ cleanup_ops(ops);
+ goto out;
+ }
+ }
+
+ err = -ENOENT;
+out:
+ spin_unlock(&rules_mod_lock);
+
+ synchronize_rcu();
+
+ return err;
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_unregister);
+
+int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
+ int flags, struct fib_lookup_arg *arg)
+{
+ struct fib_rule *rule;
+ int err;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(rule, ops->rules_list, list) {
+ if (rule->ifindex && (rule->ifindex != fl->iif))
+ continue;
+
+ if (!ops->match(rule, fl, flags))
+ continue;
+
+ err = ops->action(rule, fl, flags, arg);
+ if (err != -EAGAIN) {
+ fib_rule_get(rule);
+ arg->rule = rule;
+ goto out;
+ }
+ }
+
+ err = -ENETUNREACH;
+out:
+ rcu_read_unlock();
+
+ return err;
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_lookup);
+
+int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
+{
+ struct fib_rule_hdr *frh = nlmsg_data(nlh);
+ struct fib_rules_ops *ops = NULL;
+ struct fib_rule *rule, *r, *last = NULL;
+ struct nlattr *tb[FRA_MAX+1];
+ int err = -EINVAL;
+
+ if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
+ goto errout;
+
+ ops = lookup_rules_ops(frh->family);
+ if (ops == NULL) {
+ err = EAFNOSUPPORT;
+ goto errout;
+ }
+
+ err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
+ if (err < 0)
+ goto errout;
+
+ if (tb[FRA_IFNAME] && nla_len(tb[FRA_IFNAME]) > IFNAMSIZ)
+ goto errout;
+
+ rule = kzalloc(ops->rule_size, GFP_KERNEL);
+ if (rule == NULL) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ if (tb[FRA_PRIORITY])
+ rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
+
+ if (tb[FRA_IFNAME]) {
+ struct net_device *dev;
+
+ rule->ifindex = -1;
+ if (nla_strlcpy(rule->ifname, tb[FRA_IFNAME],
+ IFNAMSIZ) >= IFNAMSIZ)
+ goto errout_free;
+
+ dev = __dev_get_by_name(rule->ifname);
+ if (dev)
+ rule->ifindex = dev->ifindex;
+ }
+
+ rule->action = frh->action;
+ rule->flags = frh->flags;
+ rule->table = frh->table;
+
+ if (!rule->pref && ops->default_pref)
+ rule->pref = ops->default_pref();
+
+ err = ops->configure(rule, skb, nlh, frh, tb);
+ if (err < 0)
+ goto errout_free;
+
+ list_for_each_entry(r, ops->rules_list, list) {
+ if (r->pref > rule->pref)
+ break;
+ last = r;
+ }
+
+ fib_rule_get(rule);
+
+ if (last)
+ list_add_rcu(&rule->list, &last->list);
+ else
+ list_add_rcu(&rule->list, ops->rules_list);
+
+ notify_rule_change(RTM_NEWRULE, rule, ops);
+ rules_ops_put(ops);
+ return 0;
+
+errout_free:
+ kfree(rule);
+errout:
+ rules_ops_put(ops);
+ return err;
+}
+
+int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
+{
+ struct fib_rule_hdr *frh = nlmsg_data(nlh);
+ struct fib_rules_ops *ops = NULL;
+ struct fib_rule *rule;
+ struct nlattr *tb[FRA_MAX+1];
+ int err = -EINVAL;
+
+ if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
+ goto errout;
+
+ ops = lookup_rules_ops(frh->family);
+ if (ops == NULL) {
+ err = EAFNOSUPPORT;
+ goto errout;
+ }
+
+ err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy);
+ if (err < 0)
+ goto errout;
+
+ list_for_each_entry(rule, ops->rules_list, list) {
+ if (frh->action && (frh->action != rule->action))
+ continue;
+
+ if (frh->table && (frh->table != rule->table))
+ continue;
+
+ if (tb[FRA_PRIORITY] &&
+ (rule->pref != nla_get_u32(tb[FRA_PRIORITY])))
+ continue;
+
+ if (tb[FRA_IFNAME] &&
+ nla_strcmp(tb[FRA_IFNAME], rule->ifname))
+ continue;
+
+ if (!ops->compare(rule, frh, tb))
+ continue;
+
+ if (rule->flags & FIB_RULE_PERMANENT) {
+ err = -EPERM;
+ goto errout;
+ }
+
+ list_del_rcu(&rule->list);
+ synchronize_rcu();
+ notify_rule_change(RTM_DELRULE, rule, ops);
+ fib_rule_put(rule);
+ rules_ops_put(ops);
+ return 0;
+ }
+
+ err = -ENOENT;
+errout:
+ rules_ops_put(ops);
+ return err;
+}
+
+static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
+ u32 pid, u32 seq, int type, int flags,
+ struct fib_rules_ops *ops)
+{
+ struct nlmsghdr *nlh;
+ struct fib_rule_hdr *frh;
+
+ nlh = nlmsg_put(skb, pid, seq, type, sizeof(*frh), flags);
+ if (nlh == NULL)
+ return -1;
+
+ frh = nlmsg_data(nlh);
+ frh->table = rule->table;
+ frh->res1 = 0;
+ frh->res2 = 0;
+ frh->action = rule->action;
+ frh->flags = rule->flags;
+
+ if (rule->ifname[0])
+ NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);
+
+ if (rule->pref)
+ NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
+
+ if (ops->fill(rule, skb, nlh, frh) < 0)
+ goto nla_put_failure;
+
+ return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+ return nlmsg_cancel(skb, nlh);
+}
+
+int fib_rules_dump(struct sk_buff *skb, struct netlink_callback *cb, int family)
+{
+ int idx = 0;
+ struct fib_rule *rule;
+ struct fib_rules_ops *ops;
+
+ ops = lookup_rules_ops(family);
+ if (ops == NULL)
+ return -EAFNOSUPPORT;
+
+ rcu_read_lock();
+ list_for_each_entry(rule, ops->rules_list, list) {
+ if (idx < cb->args[0])
+ goto skip;
+
+ if (fib_nl_fill_rule(skb, rule, NETLINK_CB(cb->skb).pid,
+ cb->nlh->nlmsg_seq, RTM_NEWRULE,
+ NLM_F_MULTI, ops) < 0)
+ break;
+skip:
+ idx++;
+ }
+ rcu_read_unlock();
+ cb->args[0] = idx;
+ rules_ops_put(ops);
+
+ return skb->len;
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_dump);
+
+static void notify_rule_change(int event, struct fib_rule *rule,
+ struct fib_rules_ops *ops)
+{
+ int size = nlmsg_total_size(sizeof(struct fib_rule_hdr) + 128);
+ struct sk_buff *skb = alloc_skb(size, GFP_KERNEL);
+
+ if (skb == NULL)
+ netlink_set_err(rtnl, 0, ops->nlgroup, ENOBUFS);
+ else if (fib_nl_fill_rule(skb, rule, 0, 0, event, 0, ops) < 0) {
+ kfree_skb(skb);
+ netlink_set_err(rtnl, 0, ops->nlgroup, EINVAL);
+ } else
+ netlink_broadcast(rtnl, skb, 0, ops->nlgroup, GFP_KERNEL);
+}
+
+static void attach_rules(struct list_head *rules, struct net_device *dev)
+{
+ struct fib_rule *rule;
+
+ list_for_each_entry(rule, rules, list) {
+ if (rule->ifindex == -1 &&
+ strcmp(dev->name, rule->ifname) == 0)
+ rule->ifindex = dev->ifindex;
+ }
+}
+
+static void detach_rules(struct list_head *rules, struct net_device *dev)
+{
+ struct fib_rule *rule;
+
+ list_for_each_entry(rule, rules, list)
+ if (rule->ifindex == dev->ifindex)
+ rule->ifindex = -1;
+}
+
+
+static int fib_rules_event(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = ptr;
+ struct fib_rules_ops *ops;
+
+ ASSERT_RTNL();
+ rcu_read_lock();
+
+ switch (event) {
+ case NETDEV_REGISTER:
+ list_for_each_entry(ops, &rules_ops, list)
+ attach_rules(ops->rules_list, dev);
+ break;
+
+ case NETDEV_UNREGISTER:
+ list_for_each_entry(ops, &rules_ops, list)
+ detach_rules(ops->rules_list, dev);
+ break;
+ }
+
+ rcu_read_unlock();
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block fib_rules_notifier = {
+ .notifier_call = fib_rules_event,
+};
+
+static int __init fib_rules_init(void)
+{
+ return register_netdevice_notifier(&fib_rules_notifier);
+}
+
+subsys_initcall(fib_rules_init);