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)
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, 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 (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, MPTCP_SUBFLOW_ATTR_TOKEN_REM, sf->remote_token) ||
58	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_LOC, sf->token) ||
59	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ,
60			sf->rel_write_seq) ||
61	    nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq,
62			      MPTCP_SUBFLOW_ATTR_PAD) ||
63	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ,
64			sf->map_subflow_seq) ||
65	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) ||
66	    nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN,
67			sf->map_data_len) ||
68	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_FLAGS, flags) ||
69	    nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_REM, sf->remote_id) ||
70	    nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_LOC, subflow_get_local_id(sf))) {
71		err = -EMSGSIZE;
72		goto nla_failure;
73	}
74
75	rcu_read_unlock();
76	unlock_sock_fast(sk, slow);
77	nla_nest_end(skb, start);
78	return 0;
79
80nla_failure:
81	rcu_read_unlock();
82	unlock_sock_fast(sk, slow);
83	nla_nest_cancel(skb, start);
84	return err;
85}
86
87static size_t subflow_get_info_size(const struct sock *sk)
88{
89	size_t size = 0;
90
91	size += nla_total_size(0) +	/* INET_ULP_INFO_MPTCP */
92		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_TOKEN_REM */
93		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_TOKEN_LOC */
94		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */
95		nla_total_size_64bit(8) +	/* MPTCP_SUBFLOW_ATTR_MAP_SEQ */
96		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */
97		nla_total_size(2) +	/* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
98		nla_total_size(2) +	/* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */
99		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_FLAGS */
100		nla_total_size(1) +	/* MPTCP_SUBFLOW_ATTR_ID_REM */
101		nla_total_size(1) +	/* MPTCP_SUBFLOW_ATTR_ID_LOC */
102		0;
103	return size;
104}
105
106void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops)
107{
108	ops->get_info = subflow_get_info;
109	ops->get_info_size = subflow_get_info_size;
110}
111