inet_diag: allow protocols to provide additional data

Extend inet_diag_handler to allow individual protocols to report
additional data on INET_DIAG_INFO through idiag_get_aux. The size
can be dynamic and is computed by idiag_get_aux_size.

Signed-off-by: Ivan Delalande <colona@arista.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/inet_diag.h b/include/linux/inet_diag.h
index 65da430..ee251c5 100644 (file)
--- a/include/linux/inet_diag.h
+++ b/include/linux/inet_diag.h
@@ -25,6 +25,13 @@ struct inet_diag_handler {
                                          struct inet_diag_msg *r,
                                          void *info);
 
+       int             (*idiag_get_aux)(struct sock *sk,
+                                        bool net_admin,
+                                        struct sk_buff *skb);
+
+       size_t          (*idiag_get_aux_size)(struct sock *sk,
+                                             bool net_admin);
+
        int             (*destroy)(struct sk_buff *in_skb,
                                   const struct inet_diag_req_v2 *req);
 

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 67325d5..c9c35b6 100644 (file)
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -93,8 +93,17 @@ void inet_diag_msg_common_fill(struct inet_diag_msg *r, struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(inet_diag_msg_common_fill);
 
-static size_t inet_sk_attr_size(void)
+static size_t inet_sk_attr_size(struct sock *sk,
+                               const struct inet_diag_req_v2 *req,
+                               bool net_admin)
 {
+       const struct inet_diag_handler *handler;
+       size_t aux = 0;
+
+       handler = inet_diag_table[req->sdiag_protocol];
+       if (handler && handler->idiag_get_aux_size)
+               aux = handler->idiag_get_aux_size(sk, net_admin);
+
        return    nla_total_size(sizeof(struct tcp_info))
                + nla_total_size(1) /* INET_DIAG_SHUTDOWN */
                + nla_total_size(1) /* INET_DIAG_TOS */
@@ -105,6 +114,7 @@ static size_t inet_sk_attr_size(void)
                + nla_total_size(SK_MEMINFO_VARS * sizeof(u32))
                + nla_total_size(TCP_CA_NAME_MAX)
                + nla_total_size(sizeof(struct tcpvegas_info))
+               + aux
                + 64;
 }
 
@@ -260,6 +270,10 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
 
        handler->idiag_get_info(sk, r, info);
 
+       if (ext & (1 << (INET_DIAG_INFO - 1)) && handler->idiag_get_aux)
+               if (handler->idiag_get_aux(sk, net_admin, skb) < 0)
+                       goto errout;
+
        if (sk->sk_state < TCP_TIME_WAIT) {
                union tcp_cc_info info;
                size_t sz = 0;
@@ -449,6 +463,7 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo *hashinfo,
                            const struct nlmsghdr *nlh,
                            const struct inet_diag_req_v2 *req)
 {
+       bool net_admin = netlink_net_capable(in_skb, CAP_NET_ADMIN);
        struct net *net = sock_net(in_skb->sk);
        struct sk_buff *rep;
        struct sock *sk;
@@ -458,7 +473,7 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo *hashinfo,
        if (IS_ERR(sk))
                return PTR_ERR(sk);
 
-       rep = nlmsg_new(inet_sk_attr_size(), GFP_KERNEL);
+       rep = nlmsg_new(inet_sk_attr_size(sk, req, net_admin), GFP_KERNEL);
        if (!rep) {
                err = -ENOMEM;
                goto out;
@@ -467,8 +482,7 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo *hashinfo,
        err = sk_diag_fill(sk, rep, req,
                           sk_user_ns(NETLINK_CB(in_skb).sk),
                           NETLINK_CB(in_skb).portid,
-                          nlh->nlmsg_seq, 0, nlh,
-                          netlink_net_capable(in_skb, CAP_NET_ADMIN));
+                          nlh->nlmsg_seq, 0, nlh, net_admin);
        if (err < 0) {
                WARN_ON(err == -EMSGSIZE);
                nlmsg_free(rep);