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-rw-r--r--net/core/fib_rules.c685
1 files changed, 685 insertions, 0 deletions
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
new file mode 100644
index 0000000..79de3b1
--- /dev/null
+++ b/net/core/fib_rules.c
@@ -0,0 +1,685 @@
+/*
+ * 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/types.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <net/net_namespace.h>
+#include <net/sock.h>
+#include <net/fib_rules.h>
+
+int fib_default_rule_add(struct fib_rules_ops *ops,
+ u32 pref, u32 table, u32 flags)
+{
+ struct fib_rule *r;
+
+ r = kzalloc(ops->rule_size, GFP_KERNEL);
+ if (r == NULL)
+ return -ENOMEM;
+
+ atomic_set(&r->refcnt, 1);
+ r->action = FR_ACT_TO_TBL;
+ r->pref = pref;
+ r->table = table;
+ r->flags = flags;
+ r->fr_net = hold_net(ops->fro_net);
+
+ /* The lock is not required here, the list in unreacheable
+ * at the moment this function is called */
+ list_add_tail(&r->list, &ops->rules_list);
+ return 0;
+}
+EXPORT_SYMBOL(fib_default_rule_add);
+
+static void notify_rule_change(int event, struct fib_rule *rule,
+ struct fib_rules_ops *ops, struct nlmsghdr *nlh,
+ u32 pid);
+
+static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
+{
+ struct fib_rules_ops *ops;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ops, &net->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);
+}
+
+static void flush_route_cache(struct fib_rules_ops *ops)
+{
+ if (ops->flush_cache)
+ ops->flush_cache(ops);
+}
+
+int fib_rules_register(struct fib_rules_ops *ops)
+{
+ int err = -EEXIST;
+ struct fib_rules_ops *o;
+ struct net *net;
+
+ net = ops->fro_net;
+
+ 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(&net->rules_mod_lock);
+ list_for_each_entry(o, &net->rules_ops, list)
+ if (ops->family == o->family)
+ goto errout;
+
+ hold_net(net);
+ list_add_tail_rcu(&ops->list, &net->rules_ops);
+ err = 0;
+errout:
+ spin_unlock(&net->rules_mod_lock);
+
+ return err;
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_register);
+
+void fib_rules_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);
+ }
+}
+EXPORT_SYMBOL_GPL(fib_rules_cleanup_ops);
+
+void fib_rules_unregister(struct fib_rules_ops *ops)
+{
+ struct net *net = ops->fro_net;
+
+ spin_lock(&net->rules_mod_lock);
+ list_del_rcu(&ops->list);
+ fib_rules_cleanup_ops(ops);
+ spin_unlock(&net->rules_mod_lock);
+
+ synchronize_rcu();
+ release_net(net);
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_unregister);
+
+static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
+ struct flowi *fl, int flags)
+{
+ int ret = 0;
+
+ if (rule->ifindex && (rule->ifindex != fl->iif))
+ goto out;
+
+ if ((rule->mark ^ fl->mark) & rule->mark_mask)
+ goto out;
+
+ ret = ops->match(rule, fl, flags);
+out:
+ return (rule->flags & FIB_RULE_INVERT) ? !ret : ret;
+}
+
+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) {
+jumped:
+ if (!fib_rule_match(rule, ops, fl, flags))
+ continue;
+
+ if (rule->action == FR_ACT_GOTO) {
+ struct fib_rule *target;
+
+ target = rcu_dereference(rule->ctarget);
+ if (target == NULL) {
+ continue;
+ } else {
+ rule = target;
+ goto jumped;
+ }
+ } else if (rule->action == FR_ACT_NOP)
+ continue;
+ else
+ err = ops->action(rule, fl, flags, arg);
+
+ if (err != -EAGAIN) {
+ fib_rule_get(rule);
+ arg->rule = rule;
+ goto out;
+ }
+ }
+
+ err = -ESRCH;
+out:
+ rcu_read_unlock();
+
+ return err;
+}
+
+EXPORT_SYMBOL_GPL(fib_rules_lookup);
+
+static int validate_rulemsg(struct fib_rule_hdr *frh, struct nlattr **tb,
+ struct fib_rules_ops *ops)
+{
+ int err = -EINVAL;
+
+ if (frh->src_len)
+ if (tb[FRA_SRC] == NULL ||
+ frh->src_len > (ops->addr_size * 8) ||
+ nla_len(tb[FRA_SRC]) != ops->addr_size)
+ goto errout;
+
+ if (frh->dst_len)
+ if (tb[FRA_DST] == NULL ||
+ frh->dst_len > (ops->addr_size * 8) ||
+ nla_len(tb[FRA_DST]) != ops->addr_size)
+ goto errout;
+
+ err = 0;
+errout:
+ return err;
+}
+
+static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
+{
+ struct net *net = sock_net(skb->sk);
+ 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, unresolved = 0;
+
+ if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
+ goto errout;
+
+ ops = lookup_rules_ops(net, 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;
+
+ err = validate_rulemsg(frh, tb, ops);
+ if (err < 0)
+ goto errout;
+
+ rule = kzalloc(ops->rule_size, GFP_KERNEL);
+ if (rule == NULL) {
+ err = -ENOMEM;
+ goto errout;
+ }
+ rule->fr_net = hold_net(net);
+
+ if (tb[FRA_PRIORITY])
+ rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
+
+ if (tb[FRA_IFNAME]) {
+ struct net_device *dev;
+
+ rule->ifindex = -1;
+ nla_strlcpy(rule->ifname, tb[FRA_IFNAME], IFNAMSIZ);
+ dev = __dev_get_by_name(net, rule->ifname);
+ if (dev)
+ rule->ifindex = dev->ifindex;
+ }
+
+ if (tb[FRA_FWMARK]) {
+ rule->mark = nla_get_u32(tb[FRA_FWMARK]);
+ if (rule->mark)
+ /* compatibility: if the mark value is non-zero all bits
+ * are compared unless a mask is explicitly specified.
+ */
+ rule->mark_mask = 0xFFFFFFFF;
+ }
+
+ if (tb[FRA_FWMASK])
+ rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
+
+ rule->action = frh->action;
+ rule->flags = frh->flags;
+ rule->table = frh_get_table(frh, tb);
+
+ if (!rule->pref && ops->default_pref)
+ rule->pref = ops->default_pref(ops);
+
+ err = -EINVAL;
+ if (tb[FRA_GOTO]) {
+ if (rule->action != FR_ACT_GOTO)
+ goto errout_free;
+
+ rule->target = nla_get_u32(tb[FRA_GOTO]);
+ /* Backward jumps are prohibited to avoid endless loops */
+ if (rule->target <= rule->pref)
+ goto errout_free;
+
+ list_for_each_entry(r, &ops->rules_list, list) {
+ if (r->pref == rule->target) {
+ rule->ctarget = r;
+ break;
+ }
+ }
+
+ if (rule->ctarget == NULL)
+ unresolved = 1;
+ } else if (rule->action == FR_ACT_GOTO)
+ goto errout_free;
+
+ 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 (ops->unresolved_rules) {
+ /*
+ * There are unresolved goto rules in the list, check if
+ * any of them are pointing to this new rule.
+ */
+ list_for_each_entry(r, &ops->rules_list, list) {
+ if (r->action == FR_ACT_GOTO &&
+ r->target == rule->pref) {
+ BUG_ON(r->ctarget != NULL);
+ rcu_assign_pointer(r->ctarget, rule);
+ if (--ops->unresolved_rules == 0)
+ break;
+ }
+ }
+ }
+
+ if (rule->action == FR_ACT_GOTO)
+ ops->nr_goto_rules++;
+
+ if (unresolved)
+ ops->unresolved_rules++;
+
+ 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, nlh, NETLINK_CB(skb).pid);
+ flush_route_cache(ops);
+ rules_ops_put(ops);
+ return 0;
+
+errout_free:
+ release_net(rule->fr_net);
+ kfree(rule);
+errout:
+ rules_ops_put(ops);
+ return err;
+}
+
+static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
+{
+ struct net *net = sock_net(skb->sk);
+ struct fib_rule_hdr *frh = nlmsg_data(nlh);
+ struct fib_rules_ops *ops = NULL;
+ struct fib_rule *rule, *tmp;
+ struct nlattr *tb[FRA_MAX+1];
+ int err = -EINVAL;
+
+ if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
+ goto errout;
+
+ ops = lookup_rules_ops(net, 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;
+
+ err = validate_rulemsg(frh, tb, ops);
+ 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_get_table(frh, tb) != 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 (tb[FRA_FWMARK] &&
+ (rule->mark != nla_get_u32(tb[FRA_FWMARK])))
+ continue;
+
+ if (tb[FRA_FWMASK] &&
+ (rule->mark_mask != nla_get_u32(tb[FRA_FWMASK])))
+ continue;
+
+ if (!ops->compare(rule, frh, tb))
+ continue;
+
+ if (rule->flags & FIB_RULE_PERMANENT) {
+ err = -EPERM;
+ goto errout;
+ }
+
+ list_del_rcu(&rule->list);
+
+ if (rule->action == FR_ACT_GOTO)
+ ops->nr_goto_rules--;
+
+ /*
+ * Check if this rule is a target to any of them. If so,
+ * disable them. As this operation is eventually very
+ * expensive, it is only performed if goto rules have
+ * actually been added.
+ */
+ if (ops->nr_goto_rules > 0) {
+ list_for_each_entry(tmp, &ops->rules_list, list) {
+ if (tmp->ctarget == rule) {
+ rcu_assign_pointer(tmp->ctarget, NULL);
+ ops->unresolved_rules++;
+ }
+ }
+ }
+
+ synchronize_rcu();
+ notify_rule_change(RTM_DELRULE, rule, ops, nlh,
+ NETLINK_CB(skb).pid);
+ fib_rule_put(rule);
+ flush_route_cache(ops);
+ rules_ops_put(ops);
+ return 0;
+ }
+
+ err = -ENOENT;
+errout:
+ rules_ops_put(ops);
+ return err;
+}
+
+static inline size_t fib_rule_nlmsg_size(struct fib_rules_ops *ops,
+ struct fib_rule *rule)
+{
+ size_t payload = NLMSG_ALIGN(sizeof(struct fib_rule_hdr))
+ + nla_total_size(IFNAMSIZ) /* FRA_IFNAME */
+ + nla_total_size(4) /* FRA_PRIORITY */
+ + nla_total_size(4) /* FRA_TABLE */
+ + nla_total_size(4) /* FRA_FWMARK */
+ + nla_total_size(4); /* FRA_FWMASK */
+
+ if (ops->nlmsg_payload)
+ payload += ops->nlmsg_payload(rule);
+
+ return payload;
+}
+
+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 -EMSGSIZE;
+
+ frh = nlmsg_data(nlh);
+ frh->table = rule->table;
+ NLA_PUT_U32(skb, FRA_TABLE, rule->table);
+ frh->res1 = 0;
+ frh->res2 = 0;
+ frh->action = rule->action;
+ frh->flags = rule->flags;
+
+ if (rule->action == FR_ACT_GOTO && rule->ctarget == NULL)
+ frh->flags |= FIB_RULE_UNRESOLVED;
+
+ if (rule->ifname[0]) {
+ NLA_PUT_STRING(skb, FRA_IFNAME, rule->ifname);
+
+ if (rule->ifindex == -1)
+ frh->flags |= FIB_RULE_DEV_DETACHED;
+ }
+
+ if (rule->pref)
+ NLA_PUT_U32(skb, FRA_PRIORITY, rule->pref);
+
+ if (rule->mark)
+ NLA_PUT_U32(skb, FRA_FWMARK, rule->mark);
+
+ if (rule->mark_mask || rule->mark)
+ NLA_PUT_U32(skb, FRA_FWMASK, rule->mark_mask);
+
+ if (rule->target)
+ NLA_PUT_U32(skb, FRA_GOTO, rule->target);
+
+ if (ops->fill(rule, skb, nlh, frh) < 0)
+ goto nla_put_failure;
+
+ return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+ nlmsg_cancel(skb, nlh);
+ return -EMSGSIZE;
+}
+
+static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb,
+ struct fib_rules_ops *ops)
+{
+ int idx = 0;
+ struct fib_rule *rule;
+
+ list_for_each_entry(rule, &ops->rules_list, list) {
+ if (idx < cb->args[1])
+ 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++;
+ }
+ cb->args[1] = idx;
+ rules_ops_put(ops);
+
+ return skb->len;
+}
+
+static int fib_nl_dumprule(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct net *net = sock_net(skb->sk);
+ struct fib_rules_ops *ops;
+ int idx = 0, family;
+
+ family = rtnl_msg_family(cb->nlh);
+ if (family != AF_UNSPEC) {
+ /* Protocol specific dump request */
+ ops = lookup_rules_ops(net, family);
+ if (ops == NULL)
+ return -EAFNOSUPPORT;
+
+ return dump_rules(skb, cb, ops);
+ }
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ops, &net->rules_ops, list) {
+ if (idx < cb->args[0] || !try_module_get(ops->owner))
+ goto skip;
+
+ if (dump_rules(skb, cb, ops) < 0)
+ break;
+
+ cb->args[1] = 0;
+ skip:
+ idx++;
+ }
+ rcu_read_unlock();
+ cb->args[0] = idx;
+
+ return skb->len;
+}
+
+static void notify_rule_change(int event, struct fib_rule *rule,
+ struct fib_rules_ops *ops, struct nlmsghdr *nlh,
+ u32 pid)
+{
+ struct net *net;
+ struct sk_buff *skb;
+ int err = -ENOBUFS;
+
+ net = ops->fro_net;
+ skb = nlmsg_new(fib_rule_nlmsg_size(ops, rule), GFP_KERNEL);
+ if (skb == NULL)
+ goto errout;
+
+ err = fib_nl_fill_rule(skb, rule, pid, nlh->nlmsg_seq, event, 0, ops);
+ if (err < 0) {
+ /* -EMSGSIZE implies BUG in fib_rule_nlmsg_size() */
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(skb);
+ goto errout;
+ }
+
+ err = rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL);
+errout:
+ if (err < 0)
+ rtnl_set_sk_err(net, ops->nlgroup, err);
+}
+
+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 net *net = dev_net(dev);
+ struct fib_rules_ops *ops;
+
+ ASSERT_RTNL();
+ rcu_read_lock();
+
+ switch (event) {
+ case NETDEV_REGISTER:
+ list_for_each_entry(ops, &net->rules_ops, list)
+ attach_rules(&ops->rules_list, dev);
+ break;
+
+ case NETDEV_UNREGISTER:
+ list_for_each_entry(ops, &net->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 fib_rules_net_init(struct net *net)
+{
+ INIT_LIST_HEAD(&net->rules_ops);
+ spin_lock_init(&net->rules_mod_lock);
+ return 0;
+}
+
+static struct pernet_operations fib_rules_net_ops = {
+ .init = fib_rules_net_init,
+};
+
+static int __init fib_rules_init(void)
+{
+ int err;
+ rtnl_register(PF_UNSPEC, RTM_NEWRULE, fib_nl_newrule, NULL);
+ rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL);
+ rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule);
+
+ err = register_netdevice_notifier(&fib_rules_notifier);
+ if (err < 0)
+ goto fail;
+
+ err = register_pernet_subsys(&fib_rules_net_ops);
+ if (err < 0)
+ goto fail_unregister;
+ return 0;
+
+fail_unregister:
+ unregister_netdevice_notifier(&fib_rules_notifier);
+fail:
+ rtnl_unregister(PF_UNSPEC, RTM_NEWRULE);
+ rtnl_unregister(PF_UNSPEC, RTM_DELRULE);
+ rtnl_unregister(PF_UNSPEC, RTM_GETRULE);
+ return err;
+}
+
+subsys_initcall(fib_rules_init);
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