1// SPDX-License-Identifier: GPL-2.0
2/* MPTCP socket monitoring support
3 *
4 * Copyright (c) 2019 Red Hat
5 *
6 * Author: Davide Caratti <dcaratti@redhat.com>
7 */
8
9#include <linux/kernel.h>
10#include <linux/net.h>
11#include <linux/inet_diag.h>
12#include <net/netlink.h>
13#include "protocol.h"
14
15static int subflow_get_info(struct sock *sk, struct sk_buff *skb, bool net_admin)
16{
17 struct mptcp_subflow_context *sf;
18 struct nlattr *start;
19 u32 flags = 0;
20 bool slow;
21 int err;
22
23 if (inet_sk_state_load(sk) == TCP_LISTEN)
24 return 0;
25
26 start = nla_nest_start_noflag(skb, attrtype: INET_ULP_INFO_MPTCP);
27 if (!start)
28 return -EMSGSIZE;
29
30 slow = lock_sock_fast(sk);
31 rcu_read_lock();
32 sf = rcu_dereference(inet_csk(sk)->icsk_ulp_data);
33 if (!sf) {
34 err = 0;
35 goto nla_failure;
36 }
37
38 if (sf->mp_capable)
39 flags |= MPTCP_SUBFLOW_FLAG_MCAP_REM;
40 if (sf->request_mptcp)
41 flags |= MPTCP_SUBFLOW_FLAG_MCAP_LOC;
42 if (sf->mp_join)
43 flags |= MPTCP_SUBFLOW_FLAG_JOIN_REM;
44 if (sf->request_join)
45 flags |= MPTCP_SUBFLOW_FLAG_JOIN_LOC;
46 if (sf->backup)
47 flags |= MPTCP_SUBFLOW_FLAG_BKUP_REM;
48 if (sf->request_bkup)
49 flags |= MPTCP_SUBFLOW_FLAG_BKUP_LOC;
50 if (READ_ONCE(sf->fully_established))
51 flags |= MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED;
52 if (sf->conn_finished)
53 flags |= MPTCP_SUBFLOW_FLAG_CONNECTED;
54 if (sf->map_valid)
55 flags |= MPTCP_SUBFLOW_FLAG_MAPVALID;
56
57 if (nla_put_u32(skb, attrtype: MPTCP_SUBFLOW_ATTR_TOKEN_REM, value: sf->remote_token) ||
58 nla_put_u32(skb, attrtype: MPTCP_SUBFLOW_ATTR_TOKEN_LOC, value: sf->token) ||
59 nla_put_u32(skb, attrtype: MPTCP_SUBFLOW_ATTR_FLAGS, value: flags) ||
60 nla_put_u8(skb, attrtype: MPTCP_SUBFLOW_ATTR_ID_REM, value: sf->remote_id) ||
61 nla_put_u8(skb, attrtype: MPTCP_SUBFLOW_ATTR_ID_LOC, value: subflow_get_local_id(subflow: sf))) {
62 err = -EMSGSIZE;
63 goto nla_failure;
64 }
65
66 /* Only export seq related counters to user with CAP_NET_ADMIN */
67 if (net_admin &&
68 (nla_put_u32(skb, attrtype: MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ,
69 value: sf->rel_write_seq) ||
70 nla_put_u64_64bit(skb, attrtype: MPTCP_SUBFLOW_ATTR_MAP_SEQ, value: sf->map_seq,
71 padattr: MPTCP_SUBFLOW_ATTR_PAD) ||
72 nla_put_u32(skb, attrtype: MPTCP_SUBFLOW_ATTR_MAP_SFSEQ,
73 value: sf->map_subflow_seq) ||
74 nla_put_u32(skb, attrtype: MPTCP_SUBFLOW_ATTR_SSN_OFFSET, value: sf->ssn_offset) ||
75 nla_put_u16(skb, attrtype: MPTCP_SUBFLOW_ATTR_MAP_DATALEN,
76 value: sf->map_data_len))) {
77 err = -EMSGSIZE;
78 goto nla_failure;
79 }
80
81 rcu_read_unlock();
82 unlock_sock_fast(sk, slow);
83 nla_nest_end(skb, start);
84 return 0;
85
86nla_failure:
87 rcu_read_unlock();
88 unlock_sock_fast(sk, slow);
89 nla_nest_cancel(skb, start);
90 return err;
91}
92
93static size_t subflow_get_info_size(const struct sock *sk, bool net_admin)
94{
95 size_t size = 0;
96
97 size += nla_total_size(payload: 0) + /* INET_ULP_INFO_MPTCP */
98 nla_total_size(payload: 4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_REM */
99 nla_total_size(payload: 4) + /* MPTCP_SUBFLOW_ATTR_TOKEN_LOC */
100 nla_total_size(payload: 4) + /* MPTCP_SUBFLOW_ATTR_FLAGS */
101 nla_total_size(payload: 1) + /* MPTCP_SUBFLOW_ATTR_ID_REM */
102 nla_total_size(payload: 1) + /* MPTCP_SUBFLOW_ATTR_ID_LOC */
103 0;
104
105 if (net_admin)
106 size += nla_total_size(payload: 4) + /* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */
107 nla_total_size_64bit(payload: 8) + /* MPTCP_SUBFLOW_ATTR_MAP_SEQ */
108 nla_total_size(payload: 4) + /* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */
109 nla_total_size(payload: 4) + /* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
110 nla_total_size(payload: 2) + /* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */
111 0;
112
113 return size;
114}
115
116void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops)
117{
118 ops->get_info = subflow_get_info;
119 ops->get_info_size = subflow_get_info_size;
120}
121

source code of linux/net/mptcp/diag.c