diff --git a/include/linux/fib_rules.h b/include/linux/fib_rules.h index 8270aac2aa5d..ec9c7b1d3e91 100644 --- a/include/linux/fib_rules.h +++ b/include/linux/fib_rules.h @@ -7,6 +7,7 @@ /* rule is permanent, and cannot be deleted */ #define FIB_RULE_PERMANENT 1 #define FIB_RULE_INVERT 2 +#define FIB_RULE_UNRESOLVED 4 struct fib_rule_hdr { @@ -29,7 +30,7 @@ enum FRA_DST, /* destination address */ FRA_SRC, /* source address */ FRA_IFNAME, /* interface name */ - FRA_UNUSED1, + FRA_GOTO, /* target to jump to (FR_ACT_GOTO) */ FRA_UNUSED2, FRA_PRIORITY, /* priority/preference */ FRA_UNUSED3, @@ -51,7 +52,7 @@ enum { FR_ACT_UNSPEC, FR_ACT_TO_TBL, /* Pass to fixed table */ - FR_ACT_RES1, + FR_ACT_GOTO, /* Jump to another rule */ FR_ACT_RES2, FR_ACT_RES3, FR_ACT_RES4, diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h index ff3029fe9656..08bab8b6e575 100644 --- a/include/net/fib_rules.h +++ b/include/net/fib_rules.h @@ -19,6 +19,8 @@ struct fib_rule u32 flags; u32 table; u8 action; + u32 target; + struct fib_rule * ctarget; struct rcu_head rcu; }; @@ -35,6 +37,8 @@ struct fib_rules_ops struct list_head list; int rule_size; int addr_size; + int unresolved_rules; + int nr_goto_rules; int (*action)(struct fib_rule *, struct flowi *, int, @@ -66,7 +70,8 @@ struct fib_rules_ops [FRA_PRIORITY] = { .type = NLA_U32 }, \ [FRA_FWMARK] = { .type = NLA_U32 }, \ [FRA_FWMASK] = { .type = NLA_U32 }, \ - [FRA_TABLE] = { .type = NLA_U32 } + [FRA_TABLE] = { .type = NLA_U32 }, \ + [FRA_GOTO] = { .type = NLA_U32 } static inline void fib_rule_get(struct fib_rule *rule) { diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c index fdf05af16ba5..0d8bb2efb0c1 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -132,10 +132,23 @@ int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl, rcu_read_lock(); list_for_each_entry_rcu(rule, ops->rules_list, list) { +jumped: if (!fib_rule_match(rule, ops, fl, flags)) continue; - err = ops->action(rule, fl, flags, arg); + 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 + err = ops->action(rule, fl, flags, arg); + if (err != -EAGAIN) { fib_rule_get(rule); arg->rule = rule; @@ -180,7 +193,7 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) struct fib_rules_ops *ops = NULL; struct fib_rule *rule, *r, *last = NULL; struct nlattr *tb[FRA_MAX+1]; - int err = -EINVAL; + int err = -EINVAL, unresolved = 0; if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh))) goto errout; @@ -237,6 +250,28 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) if (!rule->pref && ops->default_pref) rule->pref = ops->default_pref(); + 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; @@ -249,6 +284,28 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) 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 @@ -269,7 +326,7 @@ static 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 fib_rule *rule, *tmp; struct nlattr *tb[FRA_MAX+1]; int err = -EINVAL; @@ -322,6 +379,25 @@ static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg) } 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); @@ -371,6 +447,9 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, 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); @@ -383,6 +462,9 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule, 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;