[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>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 25804cb69cf0..d587dde5897e 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -232,6 +232,12 @@ static u32 fib6_rule_default_pref(void)
         return 0x3FFF;
 }
 
+static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
+{
+        return nla_total_size(16) /* dst */
+               + nla_total_size(16); /* src */
+}
+
 static struct fib_rules_ops fib6_rules_ops = {
         .family                 = AF_INET6,
         .rule_size              = sizeof(struct fib6_rule),
@@ -241,6 +247,7 @@ static struct fib_rules_ops fib6_rules_ops = {
         .compare                = fib6_rule_compare,
         .fill                   = fib6_rule_fill,
         .default_pref           = fib6_rule_default_pref,
+        .nlmsg_payload          = fib6_rule_nlmsg_payload,
         .nlgroup                = RTNLGRP_IPV6_RULE,
         .policy                 = fib6_rule_policy,
         .rules_list             = &fib6_rules,