On Wed, 5 Jun 2019 17:39:22 +0200, Davide Caratti wrote:
> currently, only getsockopt(TCP_ULP) can be invoked to know if a ULP is on
> top of a TCP socket. Extend idiag_get_aux() and idiag_get_aux_size(),
> introduced by commit b37e88407c1d ("inet_diag: allow protocols to provide
> additional data"), to report the ULP name and other information that can
> be made available by the ULP through optional functions.
>
> Users having CAP_NET_ADMIN privileges will then be able to retrieve this
> information through inet_diag_handler, if they specify INET_DIAG_INFO in
> the request.
>
> Signed-off-by: Davide Caratti <dcara...@redhat.com>
> ---
> include/net/tcp.h | 3 +++
> include/uapi/linux/inet_diag.h | 8 ++++++++
> net/ipv4/tcp_diag.c | 34 ++++++++++++++++++++++++++++++++--
> 3 files changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 0083a14fb64f..94431562c4b4 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -2108,6 +2108,9 @@ struct tcp_ulp_ops {
> int (*init)(struct sock *sk);
> /* cleanup ulp */
> void (*release)(struct sock *sk);
> + /* diagnostic */
> + int (*get_info)(struct sock *sk, struct sk_buff *skb);
> + size_t (*get_info_size)(struct sock *sk);
>
> char name[TCP_ULP_NAME_MAX];
> struct module *owner;
> diff --git a/include/uapi/linux/inet_diag.h b/include/uapi/linux/inet_diag.h
> index e8baca85bac6..844133de3212 100644
> --- a/include/uapi/linux/inet_diag.h
> +++ b/include/uapi/linux/inet_diag.h
> @@ -153,11 +153,19 @@ enum {
> INET_DIAG_BBRINFO, /* request as INET_DIAG_VEGASINFO */
> INET_DIAG_CLASS_ID, /* request as INET_DIAG_TCLASS */
> INET_DIAG_MD5SIG,
> + INET_DIAG_ULP_INFO,
> __INET_DIAG_MAX,
> };
>
> #define INET_DIAG_MAX (__INET_DIAG_MAX - 1)
>
> +enum {
Value of 0 is commonly defined as UNSPEC (or NONE), so:
ULP_UNSPEC,
here. Also perhaps INET_ULP_..?
> + ULP_INFO_NAME,
> + __ULP_INFO_MAX,
> +};
> +
> +#define ULP_INFO_MAX (__ULP_INFO_MAX - 1)
> +
> /* INET_DIAG_MEM */
>
> struct inet_diag_meminfo {
> diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
> index 81148f7a2323..de2e9e75b8e0 100644
> --- a/net/ipv4/tcp_diag.c
> +++ b/net/ipv4/tcp_diag.c
> @@ -88,10 +88,12 @@ static int tcp_diag_put_md5sig(struct sk_buff *skb,
> static int tcp_diag_get_aux(struct sock *sk, bool net_admin,
> struct sk_buff *skb)
> {
> + struct inet_connection_sock *icsk = inet_csk(sk);
> + int err = 0;
> +
> #ifdef CONFIG_TCP_MD5SIG
> if (net_admin) {
> struct tcp_md5sig_info *md5sig;
> - int err = 0;
>
> rcu_read_lock();
> md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
> @@ -103,11 +105,33 @@ static int tcp_diag_get_aux(struct sock *sk, bool
> net_admin,
> }
> #endif
>
> - return 0;
> + if (net_admin && icsk->icsk_ulp_ops) {
> + struct nlattr *nest;
> +
> + nest = nla_nest_start_noflag(skb, INET_DIAG_ULP_INFO);
> + if (!nest) {
> + err = -EMSGSIZE;
> + goto nla_failure;
> + }
> + err = nla_put_string(skb, ULP_INFO_NAME,
> + icsk->icsk_ulp_ops->name);
> + if (err < 0)
nit: nla_put_string() does not return positive non-zero codes
> + goto nla_failure;
> + if (icsk->icsk_ulp_ops->get_info)
> + err = icsk->icsk_ulp_ops->get_info(sk, skb);
And neither should this, probably.
> + if (err < 0) {
> +nla_failure:
> + nla_nest_cancel(skb, nest);
> + return err;
> + }
> + nla_nest_end(skb, nest);
> + }
> + return err;
So just return 0 here.
> }
>
> static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
> {
> + struct inet_connection_sock *icsk = inet_csk(sk);
> size_t size = 0;
>
> #ifdef CONFIG_TCP_MD5SIG
> @@ -128,6 +152,12 @@ static size_t tcp_diag_get_aux_size(struct sock *sk,
> bool net_admin)
> }
> #endif
>
> + if (net_admin && icsk->icsk_ulp_ops) {
> + size += nla_total_size(0) /* INET_DIAG_ULP_INFO */
^^^ not sure we want those multiple spaces here.
> + + nla_total_size(TCP_ULP_NAME_MAX); /* ULP_INFO_NAME */
+ usually goes at the end of previous line
> + if (icsk->icsk_ulp_ops->get_info_size)
> + size += icsk->icsk_ulp_ops->get_info_size(sk);
I don't know the diag code, is the socket locked at this point?
> + }
> return size;
> }
>
