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[NETLINK]: Do precise netlink message allocations where possible

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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>
This commit is contained in:
Thomas Graf
2006-11-10 14:10:15 -08:00
committed by David S. Miller
parent a94f723d59
commit 339bf98ffc
21 changed files with 233 additions and 107 deletions
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39
net/core/rtnetlink.c
View File

@@ -273,6 +273,25 @@ static void copy_rtnl_link_stats(struct rtnl_link_stats *a,
a->tx_compressed = b->tx_compressed;
};
static inline size_t if_nlmsg_size(int iwbuflen)
{
return NLMSG_ALIGN(sizeof(struct ifinfomsg))
+ nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
+ nla_total_size(IFNAMSIZ) /* IFLA_QDISC */
+ nla_total_size(sizeof(struct rtnl_link_ifmap))
+ nla_total_size(sizeof(struct rtnl_link_stats))
+ nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
+ nla_total_size(MAX_ADDR_LEN) /* IFLA_BROADCAST */
+ nla_total_size(4) /* IFLA_TXQLEN */
+ nla_total_size(4) /* IFLA_WEIGHT */
+ nla_total_size(4) /* IFLA_MTU */
+ nla_total_size(4) /* IFLA_LINK */
+ nla_total_size(4) /* IFLA_MASTER */
+ nla_total_size(1) /* IFLA_OPERSTATE */
+ nla_total_size(1) /* IFLA_LINKMODE */
+ nla_total_size(iwbuflen);
}
static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
void *iwbuf, int iwbuflen, int type, u32 pid,
u32 seq, u32 change, unsigned int flags)
@@ -558,7 +577,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
struct sk_buff *nskb;
char *iw_buf = NULL, *iw = NULL;
int iw_buf_len = 0;
int err, payload;
int err;
err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy);
if (err < 0)
@@ -587,9 +606,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
}
#endif /* CONFIG_NET_WIRELESS_RTNETLINK */
payload = NLMSG_ALIGN(sizeof(struct ifinfomsg) +
nla_total_size(iw_buf_len));
nskb = nlmsg_new(nlmsg_total_size(payload), GFP_KERNEL);
nskb = nlmsg_new(if_nlmsg_size(iw_buf_len), GFP_KERNEL);
if (nskb == NULL) {
err = -ENOBUFS;
goto errout;
@@ -597,10 +614,8 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
err = rtnl_fill_ifinfo(nskb, dev, iw, iw_buf_len, RTM_NEWLINK,
NETLINK_CB(skb).pid, nlh->nlmsg_seq, 0, 0);
if (err <= 0) {
kfree_skb(nskb);
goto errout;
}
/* failure impilies BUG in if_nlmsg_size or wireless_rtnetlink_get */
BUG_ON(err < 0);
err = rtnl_unicast(nskb, NETLINK_CB(skb).pid);
errout:
@@ -639,15 +654,13 @@ void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
struct sk_buff *skb;
int err = -ENOBUFS;
skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
skb = nlmsg_new(if_nlmsg_size(0), GFP_KERNEL);
if (skb == NULL)
goto errout;
err = rtnl_fill_ifinfo(skb, dev, NULL, 0, type, 0, 0, change, 0);
if (err < 0) {
kfree_skb(skb);
goto errout;
}
/* failure implies BUG in if_nlmsg_size() */
BUG_ON(err < 0);
err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_KERNEL);
errout: