tcp_metrics: Add a field tcpm_net and verify it matches on lookup

In preparation for using one tcp metrics hash table for all network
namespaces add a field tcpm_net to struct tcp_metrics_block, and
verify that field on all hash table lookups.

Make the field tcpm_net of type possible_net_t so it takes no space
when network namespaces are disabled.

Further add a function tm_net to read that field so we can be
efficient when network namespaces are disabled and concise
the rest of the time.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 5 deletions

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index fbb42f44501e..461c3d2e1ca4 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -40,6 +40,7 @@ struct tcp_fastopen_metrics {
 
 struct tcp_metrics_block {
         struct tcp_metrics_block __rcu  *tcpm_next;
+        possible_net_t                  tcpm_net;
         struct inetpeer_addr            tcpm_saddr;
         struct inetpeer_addr            tcpm_daddr;
         unsigned long                   tcpm_stamp;
@@ -52,6 +53,11 @@ struct tcp_metrics_block {
         struct rcu_head                 rcu_head;
 };
 
+static inline struct net *tm_net(struct tcp_metrics_block *tm)
+{
+        return read_pnet(&tm->tcpm_net);
+}
+
 static bool tcp_metric_locked(struct tcp_metrics_block *tm,
                               enum tcp_metric_index idx)
 {
@@ -183,6 +189,7 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
                 if (!tm)
                         goto out_unlock;
         }
+        write_pnet(&tm->tcpm_net, net);
         tm->tcpm_saddr = *saddr;
         tm->tcpm_daddr = *daddr;
 
@@ -217,7 +224,8 @@ static struct tcp_metrics_block *__tcp_get_metrics(const struct inetpeer_addr *s
         for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_saddr, saddr) &&
-                    addr_same(&tm->tcpm_daddr, daddr))
+                    addr_same(&tm->tcpm_daddr, daddr) &&
+                    net_eq(tm_net(tm), net))
                         break;
                 depth++;
         }
@@ -258,7 +266,8 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
         for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_saddr, &saddr) &&
-                    addr_same(&tm->tcpm_daddr, &daddr))
+                    addr_same(&tm->tcpm_daddr, &daddr) &&
+                    net_eq(tm_net(tm), net))
                         break;
         }
         tcpm_check_stamp(tm, dst);
@@ -306,7 +315,8 @@ static struct tcp_metrics_block *__tcp_get_metrics_tw(struct inet_timewait_sock
         for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_saddr, &saddr) &&
-                    addr_same(&tm->tcpm_daddr, &daddr))
+                    addr_same(&tm->tcpm_daddr, &daddr) &&
+                    net_eq(tm_net(tm), net))
                         break;
         }
         return tm;
@@ -912,6 +922,8 @@ static int tcp_metrics_nl_dump(struct sk_buff *skb,
                 rcu_read_lock();
                 for (col = 0, tm = rcu_dereference(hb->chain); tm;
                      tm = rcu_dereference(tm->tcpm_next), col++) {
+                        if (!net_eq(tm_net(tm), net))
+                                continue;
                         if (col < s_col)
                                 continue;
                         if (tcp_metrics_dump_info(skb, cb, tm) < 0) {
@@ -1004,7 +1016,8 @@ static int tcp_metrics_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
         for (tm = rcu_dereference(net->ipv4.tcp_metrics_hash[hash].chain); tm;
              tm = rcu_dereference(tm->tcpm_next)) {
                 if (addr_same(&tm->tcpm_daddr, &daddr) &&
-                    (!src || addr_same(&tm->tcpm_saddr, &saddr))) {
+                    (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
+                    net_eq(tm_net(tm), net)) {
                         ret = tcp_metrics_fill_info(msg, tm);
                         break;
                 }
@@ -1081,7 +1094,8 @@ static int tcp_metrics_nl_cmd_del(struct sk_buff *skb, struct genl_info *info)
         spin_lock_bh(&tcp_metrics_lock);
         for (tm = deref_locked_genl(*pp); tm; tm = deref_locked_genl(*pp)) {
                 if (addr_same(&tm->tcpm_daddr, &daddr) &&
-                    (!src || addr_same(&tm->tcpm_saddr, &saddr))) {
+                    (!src || addr_same(&tm->tcpm_saddr, &saddr)) &&
+                    net_eq(tm_net(tm), net)) {
                         *pp = tm->tcpm_next;
                         kfree_rcu(tm, rcu_head);
                         found = true;