/* * 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 */ #include #include #include #include #include #include #include #define INVALID_UID ((uid_t) -1) #define uid_valid(uid) ((uid) != -1) #define uid_lte(a, b) ((a) <= (b)) #define uid_eq(a, b) ((a) == (b)) #define uid_gte(a, b) ((a) >= (b)) 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->uid_start = INVALID_UID; r->uid_end = INVALID_UID; 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); u32 fib_default_rule_pref(struct fib_rules_ops *ops) { struct list_head *pos; struct fib_rule *rule; if (!list_empty(&ops->rules_list)) { pos = ops->rules_list.next; if (pos->next != &ops->rules_list) { rule = list_entry(pos->next, struct fib_rule, list); if (rule->pref) return rule->pref - 1; } } return 0; } EXPORT_SYMBOL(fib_default_rule_pref); 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); } static 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; } struct fib_rules_ops * fib_rules_register(const struct fib_rules_ops *tmpl, struct net *net) { struct fib_rules_ops *ops; int err; ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL); if (ops == NULL) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&ops->rules_list); ops->fro_net = net; err = __fib_rules_register(ops); if (err) { kfree(ops); ops = ERR_PTR(err); } return ops; } EXPORT_SYMBOL_GPL(fib_rules_register); static 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); } } static void fib_rules_put_rcu(struct rcu_head *head) { struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu); struct net *net = ops->fro_net; release_net(net); kfree(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); call_rcu(&ops->rcu, fib_rules_put_rcu); } EXPORT_SYMBOL_GPL(fib_rules_unregister); static inline uid_t fib_nl_uid(struct nlattr *nla) { return nla_get_u32(nla); } static int nla_put_uid(struct sk_buff *skb, int idx, uid_t uid) { return nla_put_u32(skb, idx, uid); } static int fib_uid_range_match(struct flowi *fl, struct fib_rule *rule) { return (!uid_valid(rule->uid_start) && !uid_valid(rule->uid_end)) || (uid_gte(fl->flowi_uid, rule->uid_start) && uid_lte(fl->flowi_uid, rule->uid_end)); } static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops, struct flowi *fl, int flags) { int ret = 0; if (rule->iifindex && (rule->iifindex != fl->flowi_iif)) goto out; if (rule->oifindex && (rule->oifindex != fl->flowi_oif)) goto out; if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask) goto out; if (!fib_uid_range_match(fl, rule)) 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) { if ((arg->flags & FIB_LOOKUP_NOREF) || likely(atomic_inc_not_zero(&rule->refcnt))) { arg->rule = rule; goto out; } break; } } 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_IIFNAME]) { struct net_device *dev; rule->iifindex = -1; nla_strlcpy(rule->iifname, tb[FRA_IIFNAME], IFNAMSIZ); dev = __dev_get_by_name(net, rule->iifname); if (dev) rule->iifindex = dev->ifindex; } if (tb[FRA_OIFNAME]) { struct net_device *dev; rule->oifindex = -1; nla_strlcpy(rule->oifname, tb[FRA_OIFNAME], IFNAMSIZ); dev = __dev_get_by_name(net, rule->oifname); if (dev) rule->oifindex = 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 (!tb[FRA_PRIORITY] && 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) { RCU_INIT_POINTER(rule->ctarget, r); break; } } if (rcu_dereference_protected(rule->ctarget, 1) == NULL) unresolved = 1; } else if (rule->action == FR_ACT_GOTO) goto errout_free; /* UID start and end must either both be valid or both unspecified. */ rule->uid_start = rule->uid_end = INVALID_UID; if (tb[FRA_UID_START] || tb[FRA_UID_END]) { if (tb[FRA_UID_START] && tb[FRA_UID_END]) { rule->uid_start = fib_nl_uid(tb[FRA_UID_START]); rule->uid_end = fib_nl_uid(tb[FRA_UID_END]); } if (!uid_valid(rule->uid_start) || !uid_valid(rule->uid_end) || !uid_lte(rule->uid_start, rule->uid_end)) goto errout_free; } err = ops->configure(rule, skb, 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); 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 && rtnl_dereference(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++; 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_get_table(frh, tb) && (frh_get_table(frh, tb) != rule->table)) continue; if (tb[FRA_PRIORITY] && (rule->pref != nla_get_u32(tb[FRA_PRIORITY]))) continue; if (tb[FRA_IIFNAME] && nla_strcmp(tb[FRA_IIFNAME], rule->iifname)) continue; if (tb[FRA_OIFNAME] && nla_strcmp(tb[FRA_OIFNAME], rule->oifname)) 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 (tb[FRA_UID_START] && !uid_eq(rule->uid_start, fib_nl_uid(tb[FRA_UID_START]))) continue; if (tb[FRA_UID_END] && !uid_eq(rule->uid_end, fib_nl_uid(tb[FRA_UID_END]))) 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 (rtnl_dereference(tmp->ctarget) == rule) { rcu_assign_pointer(tmp->ctarget, NULL); ops->unresolved_rules++; } } } 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_IIFNAME */ + nla_total_size(IFNAMSIZ) /* FRA_OIFNAME */ + nla_total_size(4) /* FRA_PRIORITY */ + nla_total_size(4) /* FRA_TABLE */ + nla_total_size(4) /* FRA_FWMARK */ + nla_total_size(4) /* FRA_FWMASK */ + nla_total_size(4) /* FRA_UID_START */ + nla_total_size(4); /* FRA_UID_END */ 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->family = ops->family; 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 && rcu_dereference_raw(rule->ctarget) == NULL) frh->flags |= FIB_RULE_UNRESOLVED; if (rule->iifname[0]) { NLA_PUT_STRING(skb, FRA_IIFNAME, rule->iifname); if (rule->iifindex == -1) frh->flags |= FIB_RULE_IIF_DETACHED; } if (rule->oifname[0]) { NLA_PUT_STRING(skb, FRA_OIFNAME, rule->oifname); if (rule->oifindex == -1) frh->flags |= FIB_RULE_OIF_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 (uid_valid(rule->uid_start)) nla_put_uid(skb, FRA_UID_START, rule->uid_start); if (uid_valid(rule->uid_end)) nla_put_uid(skb, FRA_UID_END, rule->uid_end); if (ops->fill(rule, skb, 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; rcu_read_lock(); list_for_each_entry_rcu(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++; } rcu_read_unlock(); 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; } rtnl_notify(skb, net, pid, ops->nlgroup, nlh, GFP_KERNEL); return; 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->iifindex == -1 && strcmp(dev->name, rule->iifname) == 0) rule->iifindex = dev->ifindex; if (rule->oifindex == -1 && strcmp(dev->name, rule->oifname) == 0) rule->oifindex = 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->iifindex == dev->ifindex) rule->iifindex = -1; if (rule->oifindex == dev->ifindex) rule->oifindex = -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(); 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; } return NOTIFY_DONE; } static struct notifier_block fib_rules_notifier = { .notifier_call = fib_rules_event, }; static int __net_init 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, NULL); rtnl_register(PF_UNSPEC, RTM_DELRULE, fib_nl_delrule, NULL, NULL); rtnl_register(PF_UNSPEC, RTM_GETRULE, NULL, fib_nl_dumprule, NULL); err = register_pernet_subsys(&fib_rules_net_ops); if (err < 0) goto fail; err = register_netdevice_notifier(&fib_rules_notifier); if (err < 0) goto fail_unregister; return 0; fail_unregister: unregister_pernet_subsys(&fib_rules_net_ops); 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);