[NETLINK]: Do precise netlink message allocations where possible
Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.
Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 4148e27..1df6cd45 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -306,6 +306,22 @@
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)
@@ -384,15 +400,13 @@
struct sk_buff *skb;
int err = -ENOBUFS;
- skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+ 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) {
- kfree_skb(skb);
- goto errout;
- }
+ /* failure implies BUG in fib_rule_nlmsg_size() */
+ BUG_ON(err < 0);
err = rtnl_notify(skb, pid, ops->nlgroup, nlh, GFP_KERNEL);
errout: