fib_rules: move common handling of newrule delrule msgs into fib_nl2rule

This reduces code duplication in the fib rule add and del paths.
Get rid of validate_rulemsg. This became obvious when adding duplicate
extack support in fib newrule/delrule error paths.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/fib_rules.c

@@ -387,206 +387,185 @@ unsigned int fib_rules_seq_read(struct net *net, int family)
 }
 EXPORT_SYMBOL_GPL(fib_rules_seq_read);
 
-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 rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
-		       struct nlattr **tb, struct fib_rule *rule)
+static struct fib_rule *rule_find(struct fib_rules_ops *ops,
+				  struct fib_rule_hdr *frh,
+				  struct nlattr **tb,
+				  struct fib_rule *rule,
+				  bool user_priority)
 {
 	struct fib_rule *r;
 
 	list_for_each_entry(r, &ops->rules_list, list) {
-		if (r->action != rule->action)
+		if (rule->action && r->action != rule->action)
 			continue;
 
-		if (r->table != rule->table)
+		if (rule->table && r->table != rule->table)
 			continue;
 
-		if (r->pref != rule->pref)
+		if (user_priority && r->pref != rule->pref)
 			continue;
 
-		if (memcmp(r->iifname, rule->iifname, IFNAMSIZ))
+		if (rule->iifname[0] &&
+		    memcmp(r->iifname, rule->iifname, IFNAMSIZ))
 			continue;
 
-		if (memcmp(r->oifname, rule->oifname, IFNAMSIZ))
+		if (rule->oifname[0] &&
+		    memcmp(r->oifname, rule->oifname, IFNAMSIZ))
 			continue;
 
-		if (r->mark != rule->mark)
+		if (rule->mark && r->mark != rule->mark)
 			continue;
 
-		if (r->mark_mask != rule->mark_mask)
+		if (rule->mark_mask && r->mark_mask != rule->mark_mask)
 			continue;
 
-		if (r->tun_id != rule->tun_id)
+		if (rule->tun_id && r->tun_id != rule->tun_id)
 			continue;
 
 		if (r->fr_net != rule->fr_net)
 			continue;
 
-		if (r->l3mdev != rule->l3mdev)
+		if (rule->l3mdev && r->l3mdev != rule->l3mdev)
 			continue;
 
-		if (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
-		    !uid_eq(r->uid_range.end, rule->uid_range.end))
+		if (uid_range_set(&rule->uid_range) &&
+		    (!uid_eq(r->uid_range.start, rule->uid_range.start) ||
+		    !uid_eq(r->uid_range.end, rule->uid_range.end)))
 			continue;
 
-		if (r->ip_proto != rule->ip_proto)
+		if (rule->ip_proto && r->ip_proto != rule->ip_proto)
 			continue;
 
-		if (!fib_rule_port_range_compare(&r->sport_range,
+		if (fib_rule_port_range_set(&rule->sport_range) &&
+		    !fib_rule_port_range_compare(&r->sport_range,
 						 &rule->sport_range))
 			continue;
 
-		if (!fib_rule_port_range_compare(&r->dport_range,
+		if (fib_rule_port_range_set(&rule->dport_range) &&
+		    !fib_rule_port_range_compare(&r->dport_range,
 						 &rule->dport_range))
 			continue;
 
 		if (!ops->compare(r, frh, tb))
 			continue;
-		return 1;
+		return r;
 	}
-	return 0;
+
+	return NULL;
 }
 
-int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
-		   struct netlink_ext_ack *extack)
+static int fib_nl2rule(struct sk_buff *skb, struct nlmsghdr *nlh,
+		       struct netlink_ext_ack *extack,
+		       struct fib_rules_ops *ops,
+		       struct nlattr *tb[],
+		       struct fib_rule **rule,
+		       bool *user_priority)
 {
 	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;
-	}
+	struct fib_rule *nlrule = NULL;
+	int err = -EINVAL;
 
-	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
-	if (err < 0)
-		goto errout;
+	if (frh->src_len)
+		if (!tb[FRA_SRC] ||
+		    frh->src_len > (ops->addr_size * 8) ||
+		    nla_len(tb[FRA_SRC]) != ops->addr_size)
+			goto errout;
 
-	err = validate_rulemsg(frh, tb, ops);
-	if (err < 0)
-		goto errout;
+	if (frh->dst_len)
+		if (!tb[FRA_DST] ||
+		    frh->dst_len > (ops->addr_size * 8) ||
+		    nla_len(tb[FRA_DST]) != ops->addr_size)
+			goto errout;
 
-	rule = kzalloc(ops->rule_size, GFP_KERNEL);
-	if (rule == NULL) {
+	nlrule = kzalloc(ops->rule_size, GFP_KERNEL);
+	if (!nlrule) {
 		err = -ENOMEM;
 		goto errout;
 	}
-	refcount_set(&rule->refcnt, 1);
-	rule->fr_net = net;
+	refcount_set(&nlrule->refcnt, 1);
+	nlrule->fr_net = net;
 
-	rule->pref = tb[FRA_PRIORITY] ? nla_get_u32(tb[FRA_PRIORITY])
-	                              : fib_default_rule_pref(ops);
+	if (tb[FRA_PRIORITY]) {
+		nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
+		*user_priority = true;
+	} else {
+		nlrule->pref = fib_default_rule_pref(ops);
+	}
 
-	rule->proto = tb[FRA_PROTOCOL] ?
+	nlrule->proto = tb[FRA_PROTOCOL] ?
 		nla_get_u8(tb[FRA_PROTOCOL]) : RTPROT_UNSPEC;
 
 	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);
+		nlrule->iifindex = -1;
+		nla_strlcpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
+		dev = __dev_get_by_name(net, nlrule->iifname);
 		if (dev)
-			rule->iifindex = dev->ifindex;
+			nlrule->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);
+		nlrule->oifindex = -1;
+		nla_strlcpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
+		dev = __dev_get_by_name(net, nlrule->oifname);
 		if (dev)
-			rule->oifindex = dev->ifindex;
+			nlrule->oifindex = dev->ifindex;
 	}
 
 	if (tb[FRA_FWMARK]) {
-		rule->mark = nla_get_u32(tb[FRA_FWMARK]);
-		if (rule->mark)
+		nlrule->mark = nla_get_u32(tb[FRA_FWMARK]);
+		if (nlrule->mark)
 			/* compatibility: if the mark value is non-zero all bits
 			 * are compared unless a mask is explicitly specified.
 			 */
-			rule->mark_mask = 0xFFFFFFFF;
+			nlrule->mark_mask = 0xFFFFFFFF;
 	}
 
 	if (tb[FRA_FWMASK])
-		rule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
+		nlrule->mark_mask = nla_get_u32(tb[FRA_FWMASK]);
 
 	if (tb[FRA_TUN_ID])
-		rule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
+		nlrule->tun_id = nla_get_be64(tb[FRA_TUN_ID]);
 
 	err = -EINVAL;
 	if (tb[FRA_L3MDEV]) {
 #ifdef CONFIG_NET_L3_MASTER_DEV
-		rule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
-		if (rule->l3mdev != 1)
+		nlrule->l3mdev = nla_get_u8(tb[FRA_L3MDEV]);
+		if (nlrule->l3mdev != 1)
 #endif
 			goto errout_free;
 	}
 
-	rule->action = frh->action;
-	rule->flags = frh->flags;
-	rule->table = frh_get_table(frh, tb);
+	nlrule->action = frh->action;
+	nlrule->flags = frh->flags;
+	nlrule->table = frh_get_table(frh, tb);
 	if (tb[FRA_SUPPRESS_PREFIXLEN])
-		rule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
+		nlrule->suppress_prefixlen = nla_get_u32(tb[FRA_SUPPRESS_PREFIXLEN]);
 	else
-		rule->suppress_prefixlen = -1;
+		nlrule->suppress_prefixlen = -1;
 
 	if (tb[FRA_SUPPRESS_IFGROUP])
-		rule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
+		nlrule->suppress_ifgroup = nla_get_u32(tb[FRA_SUPPRESS_IFGROUP]);
 	else
-		rule->suppress_ifgroup = -1;
+		nlrule->suppress_ifgroup = -1;
 
 	if (tb[FRA_GOTO]) {
-		if (rule->action != FR_ACT_GOTO)
+		if (nlrule->action != FR_ACT_GOTO)
 			goto errout_free;
 
-		rule->target = nla_get_u32(tb[FRA_GOTO]);
+		nlrule->target = nla_get_u32(tb[FRA_GOTO]);
 		/* Backward jumps are prohibited to avoid endless loops */
-		if (rule->target <= rule->pref)
+		if (nlrule->target <= nlrule->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)
+	} else if (nlrule->action == FR_ACT_GOTO) {
 		goto errout_free;
+	}
 
-	if (rule->l3mdev && rule->table)
+	if (nlrule->l3mdev && nlrule->table)
 		goto errout_free;
 
 	if (tb[FRA_UID_RANGE]) {
@@ -595,34 +574,72 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 			goto errout_free;
 		}
 
-		rule->uid_range = nla_get_kuid_range(tb);
+		nlrule->uid_range = nla_get_kuid_range(tb);
 
-		if (!uid_range_set(&rule->uid_range) ||
-		    !uid_lte(rule->uid_range.start, rule->uid_range.end))
+		if (!uid_range_set(&nlrule->uid_range) ||
+		    !uid_lte(nlrule->uid_range.start, nlrule->uid_range.end))
 			goto errout_free;
 	} else {
-		rule->uid_range = fib_kuid_range_unset;
+		nlrule->uid_range = fib_kuid_range_unset;
 	}
 
 	if (tb[FRA_IP_PROTO])
-		rule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
+		nlrule->ip_proto = nla_get_u8(tb[FRA_IP_PROTO]);
 
 	if (tb[FRA_SPORT_RANGE]) {
 		err = nla_get_port_range(tb[FRA_SPORT_RANGE],
-					 &rule->sport_range);
+					 &nlrule->sport_range);
 		if (err)
 			goto errout_free;
 	}
 
 	if (tb[FRA_DPORT_RANGE]) {
 		err = nla_get_port_range(tb[FRA_DPORT_RANGE],
-					 &rule->dport_range);
+					 &nlrule->dport_range);
 		if (err)
 			goto errout_free;
 	}
 
+	*rule = nlrule;
+
+	return 0;
+
+errout_free:
+	kfree(nlrule);
+errout:
+	return err;
+}
+
+int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
+		   struct netlink_ext_ack *extack)
+{
+	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 = NULL, *r, *last = NULL;
+	struct nlattr *tb[FRA_MAX + 1];
+	int err = -EINVAL, unresolved = 0;
+	bool user_priority = false;
+
+	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
+		goto errout;
+
+	ops = lookup_rules_ops(net, frh->family);
+	if (!ops) {
+		err = -EAFNOSUPPORT;
+		goto errout;
+	}
+
+	err = nlmsg_parse(nlh, sizeof(*frh), tb, FRA_MAX, ops->policy, extack);
+	if (err < 0)
+		goto errout;
+
+	err = fib_nl2rule(skb, nlh, extack, ops, tb, &rule, &user_priority);
+	if (err)
+		goto errout;
+
 	if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
-	    rule_exists(ops, frh, tb, rule)) {
+	    rule_find(ops, frh, tb, rule, user_priority)) {
 		err = -EEXIST;
 		goto errout_free;
 	}
@@ -636,6 +653,16 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		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;
+
 	list_for_each_entry(r, &ops->rules_list, list) {
 		if (r->pref > rule->pref)
 			break;
@@ -690,13 +717,11 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 {
 	struct net *net = sock_net(skb->sk);
 	struct fib_rule_hdr *frh = nlmsg_data(nlh);
-	struct fib_rule_port_range sprange = {0, 0};
-	struct fib_rule_port_range dprange = {0, 0};
 	struct fib_rules_ops *ops = NULL;
-	struct fib_rule *rule, *r;
+	struct fib_rule *rule = NULL, *r, *nlrule = NULL;
 	struct nlattr *tb[FRA_MAX+1];
-	struct fib_kuid_range range;
 	int err = -EINVAL;
+	bool user_priority = false;
 
 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*frh)))
 		goto errout;
@@ -711,150 +736,73 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		goto errout;
 
-	err = validate_rulemsg(frh, tb, ops);
-	if (err < 0)
+	err = fib_nl2rule(skb, nlh, extack, ops, tb, &nlrule, &user_priority);
+	if (err)
 		goto errout;
 
-	if (tb[FRA_UID_RANGE]) {
-		range = nla_get_kuid_range(tb);
-		if (!uid_range_set(&range)) {
-			err = -EINVAL;
-			goto errout;
-		}
-	} else {
-		range = fib_kuid_range_unset;
+	rule = rule_find(ops, frh, tb, nlrule, user_priority);
+	if (!rule) {
+		err = -ENOENT;
+		goto errout;
 	}
 
-	if (tb[FRA_SPORT_RANGE]) {
-		err = nla_get_port_range(tb[FRA_SPORT_RANGE],
-					 &sprange);
-		if (err)
-			goto errout;
+	if (rule->flags & FIB_RULE_PERMANENT) {
+		err = -EPERM;
+		goto errout;
 	}
 
-	if (tb[FRA_DPORT_RANGE]) {
-		err = nla_get_port_range(tb[FRA_DPORT_RANGE],
-					 &dprange);
+	if (ops->delete) {
+		err = ops->delete(rule);
 		if (err)
 			goto errout;
 	}
 
-	list_for_each_entry(rule, &ops->rules_list, list) {
-		if (tb[FRA_PROTOCOL] &&
-		    (rule->proto != nla_get_u8(tb[FRA_PROTOCOL])))
-			continue;
-
-		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_TUN_ID] &&
-		    (rule->tun_id != nla_get_be64(tb[FRA_TUN_ID])))
-			continue;
-
-		if (tb[FRA_L3MDEV] &&
-		    (rule->l3mdev != nla_get_u8(tb[FRA_L3MDEV])))
-			continue;
-
-		if (uid_range_set(&range) &&
-		    (!uid_eq(rule->uid_range.start, range.start) ||
-		     !uid_eq(rule->uid_range.end, range.end)))
-			continue;
-
-		if (tb[FRA_IP_PROTO] &&
-		    (rule->ip_proto != nla_get_u8(tb[FRA_IP_PROTO])))
-			continue;
-
-		if (fib_rule_port_range_set(&sprange) &&
-		    !fib_rule_port_range_compare(&rule->sport_range, &sprange))
-			continue;
-
-		if (fib_rule_port_range_set(&dprange) &&
-		    !fib_rule_port_range_compare(&rule->dport_range, &dprange))
-			continue;
-
-		if (!ops->compare(rule, frh, tb))
-			continue;
-
-		if (rule->flags & FIB_RULE_PERMANENT) {
-			err = -EPERM;
-			goto errout;
-		}
-
-		if (ops->delete) {
-			err = ops->delete(rule);
-			if (err)
-				goto errout;
-		}
-
-		if (rule->tun_id)
-			ip_tunnel_unneed_metadata();
+	if (rule->tun_id)
+		ip_tunnel_unneed_metadata();
 
-		list_del_rcu(&rule->list);
+	list_del_rcu(&rule->list);
 
-		if (rule->action == FR_ACT_GOTO) {
-			ops->nr_goto_rules--;
-			if (rtnl_dereference(rule->ctarget) == NULL)
-				ops->unresolved_rules--;
-		}
+	if (rule->action == FR_ACT_GOTO) {
+		ops->nr_goto_rules--;
+		if (rtnl_dereference(rule->ctarget) == NULL)
+			ops->unresolved_rules--;
+	}
 
-		/*
-		 * Check if this rule is a target to any of them. If so,
-		 * adjust to the next one with the same preference or
-		 * disable them. As this operation is eventually very
-		 * expensive, it is only performed if goto rules, except
-		 * current if it is goto rule, have actually been added.
-		 */
-		if (ops->nr_goto_rules > 0) {
-			struct fib_rule *n;
-
-			n = list_next_entry(rule, list);
-			if (&n->list == &ops->rules_list || n->pref != rule->pref)
-				n = NULL;
-			list_for_each_entry(r, &ops->rules_list, list) {
-				if (rtnl_dereference(r->ctarget) != rule)
-					continue;
-				rcu_assign_pointer(r->ctarget, n);
-				if (!n)
-					ops->unresolved_rules++;
-			}
+	/*
+	 * Check if this rule is a target to any of them. If so,
+	 * adjust to the next one with the same preference or
+	 * disable them. As this operation is eventually very
+	 * expensive, it is only performed if goto rules, except
+	 * current if it is goto rule, have actually been added.
+	 */
+	if (ops->nr_goto_rules > 0) {
+		struct fib_rule *n;
+
+		n = list_next_entry(rule, list);
+		if (&n->list == &ops->rules_list || n->pref != rule->pref)
+			n = NULL;
+		list_for_each_entry(r, &ops->rules_list, list) {
+			if (rtnl_dereference(r->ctarget) != rule)
+				continue;
+			rcu_assign_pointer(r->ctarget, n);
+			if (!n)
+				ops->unresolved_rules++;
 		}
-
-		call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
-					NULL);
-		notify_rule_change(RTM_DELRULE, rule, ops, nlh,
-				   NETLINK_CB(skb).portid);
-		fib_rule_put(rule);
-		flush_route_cache(ops);
-		rules_ops_put(ops);
-		return 0;
 	}
 
-	err = -ENOENT;
+	call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule, ops,
+				NULL);
+	notify_rule_change(RTM_DELRULE, rule, ops, nlh,
+			   NETLINK_CB(skb).portid);
+	fib_rule_put(rule);
+	flush_route_cache(ops);
+	rules_ops_put(ops);
+	kfree(nlrule);
+	return 0;
+
 errout:
+	if (nlrule)
+		kfree(nlrule);
 	rules_ops_put(ops);
 	return err;
 }