Re: [PATCH net-next v3 1/2] inet_diag: allow protocols to provide additional data

[Stephen Hemminger]

On Tue, 29 Aug 2017 15:29:53 -0700
Ivan Delalande  wrote:

> @@ -452,13 +466,14 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo 
> *hashinfo,
>   struct net *net = sock_net(in_skb->sk);
>   struct sk_buff *rep;
>   struct sock *sk;
> + bool net_admin = netlink_net_capable(in_skb, CAP_NET_ADMIN);

Please keep declarations in Christmas tree order if possible.

int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
  struct sk_buff *skb, const struct inet_diag_req_v2 *req,
  struct user_namespace *user_ns,
  u32 portid, u32 seq, u16 nlmsg_flags,
  const struct nlmsghdr *unlh,
  bool net_admin)
{
bool net_admin = netlink_net_capable(in_skb, CAP_NET_ADMIN);
const struct tcp_congestion_ops *ca_ops;
const struct inet_diag_handler *handler;
int ext = req->idiag_ext;
struct inet_diag_msg *r;
struct nlmsghdr  *nlh;
struct nlattr *attr;
void *info = NULL;

[PATCH net-next v3 1/2] inet_diag: allow protocols to provide additional data

[Ivan Delalande]

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 
---
 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..8a88ef373395 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);
+
returnnla_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))
+   + nla_total_size(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;
@@ -452,13 +466,14 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo 
*hashinfo,
struct net *net = sock_net(in_skb->sk);
struct sk_buff *rep;
struct sock *sk;
+   bool net_admin = netlink_net_capable(in_skb, CAP_NET_ADMIN);
int err;
 
sk = inet_diag_find_one_icsk(net, hashinfo, req);
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