[PATCH net-next v5 1/2] inet_diag: allow protocols to provide additional data

Ivan Delalande
2017-08-31T16:59:40Z

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>
---
include/linux/inet_diag.h | 7 +++++++
net/ipv4/inet_diag.c | 22 ++++++++++++++++++----
2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/include/linux/inet_diag.h b/include/linux/inet_diag.h
index 65da430e260f..ee251c585854 100644
--- 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 67325d5832d7..c9c35b61a027 100644
--- 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);
--
2.14.1