net/ipv4: Add support for specifying metric of connected routes

Add support for IFA_RT_PRIORITY to ipv4 addresses.

If the metric is changed on an existing address then the new route
is inserted before removing the old one. Since the metric is one
of the route keys, the prefix route can not be replaced.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 0 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 40f001782c1b..d7585ab1a77a 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -99,6 +99,7 @@ static const struct nla_policy ifa_ipv4_policy[IFA_MAX+1] = {
         [IFA_LABEL]             = { .type = NLA_STRING, .len = IFNAMSIZ - 1 },
         [IFA_CACHEINFO]         = { .len = sizeof(struct ifa_cacheinfo) },
         [IFA_FLAGS]             = { .type = NLA_U32 },
+        [IFA_RT_PRIORITY]       = { .type = NLA_U32 },
 };
 
 #define IN4_ADDR_HSIZE_SHIFT    8
@@ -835,6 +836,9 @@ static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
         else
                 memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
 
+        if (tb[IFA_RT_PRIORITY])
+                ifa->ifa_rt_priority = nla_get_u32(tb[IFA_RT_PRIORITY]);
+
         if (tb[IFA_CACHEINFO]) {
                 struct ifa_cacheinfo *ci;
 
@@ -906,12 +910,20 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
                 return __inet_insert_ifa(ifa, nlh, NETLINK_CB(skb).portid,
                                          extack);
         } else {
+                u32 new_metric = ifa->ifa_rt_priority;
+
                 inet_free_ifa(ifa);
 
                 if (nlh->nlmsg_flags & NLM_F_EXCL ||
                     !(nlh->nlmsg_flags & NLM_F_REPLACE))
                         return -EEXIST;
                 ifa = ifa_existing;
+
+                if (ifa->ifa_rt_priority != new_metric) {
+                        fib_modify_prefix_metric(ifa, new_metric);
+                        ifa->ifa_rt_priority = new_metric;
+                }
+
                 set_ifa_lifetime(ifa, valid_lft, prefered_lft);
                 cancel_delayed_work(&check_lifetime_work);
                 queue_delayed_work(system_power_efficient_wq,
@@ -1549,6 +1561,7 @@ static size_t inet_nlmsg_size(void)
                + nla_total_size(4) /* IFA_BROADCAST */
                + nla_total_size(IFNAMSIZ) /* IFA_LABEL */
                + nla_total_size(4)  /* IFA_FLAGS */
+               + nla_total_size(4)  /* IFA_RT_PRIORITY */
                + nla_total_size(sizeof(struct ifa_cacheinfo)); /* IFA_CACHEINFO */
 }
 
@@ -1618,6 +1631,8 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
             (ifa->ifa_label[0] &&
              nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
             nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||
+            (ifa->ifa_rt_priority &&
+             nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) ||
             put_cacheinfo(skb, ifa->ifa_cstamp, ifa->ifa_tstamp,
                           preferred, valid))
                 goto nla_put_failure;