[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/decnet/dn_table.c b/net/decnet/dn_table.c
index 317904b..e74b744 100644
--- a/net/decnet/dn_table.c
+++ b/net/decnet/dn_table.c
@@ -263,6 +263,32 @@
return 0;
}
+static inline size_t dn_fib_nlmsg_size(struct dn_fib_info *fi)
+{
+ size_t payload = NLMSG_ALIGN(struct rtmsg)
+ + nla_total_size(4) /* RTA_TABLE */
+ + nla_total_size(2) /* RTA_DST */
+ + nla_total_size(4); /* RTA_PRIORITY */
+
+ /* space for nested metrics */
+ payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
+
+ if (fi->fib_nhs) {
+ /* Also handles the special case fib_nhs == 1 */
+
+ /* each nexthop is packed in an attribute */
+ size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
+
+ /* may contain a gateway attribute */
+ nhsize += nla_total_size(4);
+
+ /* all nexthops are packed in a nested attribute */
+ payload += nla_total_size(fi->fib_nhs * nhsize);
+ }
+
+ return payload;
+}
+
static int dn_fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
u32 tb_id, u8 type, u8 scope, void *dst, int dst_len,
struct dn_fib_info *fi, unsigned int flags)
@@ -335,17 +361,15 @@
u32 pid = req ? req->pid : 0;
int err = -ENOBUFS;
- skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+ skb = nlmsg_new(dn_fib_nlmsg_size(DN_FIB_INFO(f), GFP_KERNEL));
if (skb == NULL)
goto errout;
err = dn_fib_dump_info(skb, pid, nlh->nlmsg_seq, event, tb_id,
f->fn_type, f->fn_scope, &f->fn_key, z,
DN_FIB_INFO(f), 0);
- if (err < 0) {
- kfree_skb(skb);
- goto errout;
- }
+ /* failure implies BUG in dn_fib_nlmsg_size() */
+ BUG_ON(err < 0);
err = rtnl_notify(skb, pid, RTNLGRP_DECnet_ROUTE, nlh, GFP_KERNEL);
errout: