[NETLINK]: Do precise netlink message allocations where possible

[net-next-2.6.git] / net / core / rtnetlink.c

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 02f3c794789815e5a39717e3caf6eb3119c035e9..50d6cb40c6e31d899f91d34e0cfdf4e09c7a2da1 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -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: