net: fib_rules: Split fib_nl2rule().

We will move RTNL down to fib_nl_newrule() and fib_nl_delrule().

Some operations in fib_nl2rule() require RTNL: fib_default_rule_pref()
and __dev_get_by_name().

Let's split the RTNL parts as fib_nl2rule_rtnl().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250207072502.87775-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 87f7311995383429640669be2d0d0b5102945089..694a8c2884a8f19e70d032bda02a64628e0c0627 100644 (file)
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -550,30 +550,18 @@ static int fib_nl2rule(struct net *net, struct nlmsghdr *nlh,
        if (tb[FRA_PRIORITY]) {
                nlrule->pref = nla_get_u32(tb[FRA_PRIORITY]);
                *user_priority = true;
-       } else {
-               nlrule->pref = fib_default_rule_pref(ops);
        }
 
        nlrule->proto = nla_get_u8_default(tb[FRA_PROTOCOL], RTPROT_UNSPEC);
 
        if (tb[FRA_IIFNAME]) {
-               struct net_device *dev;
-
                nlrule->iifindex = -1;
                nla_strscpy(nlrule->iifname, tb[FRA_IIFNAME], IFNAMSIZ);
-               dev = __dev_get_by_name(net, nlrule->iifname);
-               if (dev)
-                       nlrule->iifindex = dev->ifindex;
        }
 
        if (tb[FRA_OIFNAME]) {
-               struct net_device *dev;
-
                nlrule->oifindex = -1;
                nla_strscpy(nlrule->oifname, tb[FRA_OIFNAME], IFNAMSIZ);
-               dev = __dev_get_by_name(net, nlrule->oifname);
-               if (dev)
-                       nlrule->oifindex = dev->ifindex;
        }
 
        if (tb[FRA_FWMARK]) {
@@ -615,11 +603,6 @@ static int fib_nl2rule(struct net *net, struct nlmsghdr *nlh,
                }
 
                nlrule->target = nla_get_u32(tb[FRA_GOTO]);
-               /* Backward jumps are prohibited to avoid endless loops */
-               if (nlrule->target <= nlrule->pref) {
-                       NL_SET_ERR_MSG(extack, "Backward goto not supported");
-                       goto errout_free;
-               }
        } else if (nlrule->action == FR_ACT_GOTO) {
                NL_SET_ERR_MSG(extack, "Missing goto target for action goto");
                goto errout_free;
@@ -679,6 +662,39 @@ errout:
        return err;
 }
 
+static int fib_nl2rule_rtnl(struct fib_rule *nlrule,
+                           struct fib_rules_ops *ops,
+                           struct nlattr *tb[],
+                           struct netlink_ext_ack *extack)
+{
+       if (!tb[FRA_PRIORITY])
+               nlrule->pref = fib_default_rule_pref(ops);
+
+       /* Backward jumps are prohibited to avoid endless loops */
+       if (tb[FRA_GOTO] && nlrule->target <= nlrule->pref) {
+               NL_SET_ERR_MSG(extack, "Backward goto not supported");
+               return -EINVAL;
+       }
+
+       if (tb[FRA_IIFNAME]) {
+               struct net_device *dev;
+
+               dev = __dev_get_by_name(nlrule->fr_net, nlrule->iifname);
+               if (dev)
+                       nlrule->iifindex = dev->ifindex;
+       }
+
+       if (tb[FRA_OIFNAME]) {
+               struct net_device *dev;
+
+               dev = __dev_get_by_name(nlrule->fr_net, nlrule->oifname);
+               if (dev)
+                       nlrule->oifindex = dev->ifindex;
+       }
+
+       return 0;
+}
+
 static int rule_exists(struct fib_rules_ops *ops, struct fib_rule_hdr *frh,
                       struct nlattr **tb, struct fib_rule *rule)
 {
@@ -801,6 +817,10 @@ int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (err)
                goto errout;
 
+       err = fib_nl2rule_rtnl(rule, ops, tb, extack);
+       if (err)
+               goto errout_free;
+
        if ((nlh->nlmsg_flags & NLM_F_EXCL) &&
            rule_exists(ops, frh, tb, rule)) {
                err = -EEXIST;
@@ -909,6 +929,10 @@ int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (err)
                goto errout;
 
+       err = fib_nl2rule_rtnl(nlrule, ops, tb, extack);
+       if (err)
+               goto errout;
+
        rule = rule_find(ops, frh, tb, nlrule, user_priority);
        if (!rule) {
                err = -ENOENT;