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 <uapi/linux/mptcp.h>
 14#include "protocol.h"
 15
 16static int subflow_get_info(struct sock *sk, struct sk_buff *skb)
 17{
 18	struct mptcp_subflow_context *sf;
 19	struct nlattr *start;
 20	u32 flags = 0;
 21	bool slow;
 22	int err;
 23
 24	if (inet_sk_state_load(sk) == TCP_LISTEN)
 25		return 0;
 26
 27	start = nla_nest_start_noflag(skb, INET_ULP_INFO_MPTCP);
 28	if (!start)
 29		return -EMSGSIZE;
 30
 31	slow = lock_sock_fast(sk);
 32	rcu_read_lock();
 33	sf = rcu_dereference(inet_csk(sk)->icsk_ulp_data);
 34	if (!sf) {
 35		err = 0;
 36		goto nla_failure;
 37	}
 38
 39	if (sf->mp_capable)
 40		flags |= MPTCP_SUBFLOW_FLAG_MCAP_REM;
 41	if (sf->request_mptcp)
 42		flags |= MPTCP_SUBFLOW_FLAG_MCAP_LOC;
 43	if (sf->mp_join)
 44		flags |= MPTCP_SUBFLOW_FLAG_JOIN_REM;
 45	if (sf->request_join)
 46		flags |= MPTCP_SUBFLOW_FLAG_JOIN_LOC;
 47	if (sf->backup)
 48		flags |= MPTCP_SUBFLOW_FLAG_BKUP_REM;
 49	if (sf->request_bkup)
 50		flags |= MPTCP_SUBFLOW_FLAG_BKUP_LOC;
 51	if (sf->fully_established)
 52		flags |= MPTCP_SUBFLOW_FLAG_FULLY_ESTABLISHED;
 53	if (sf->conn_finished)
 54		flags |= MPTCP_SUBFLOW_FLAG_CONNECTED;
 55	if (sf->map_valid)
 56		flags |= MPTCP_SUBFLOW_FLAG_MAPVALID;
 57
 58	if (nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_REM, sf->remote_token) ||
 59	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_TOKEN_LOC, sf->token) ||
 60	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ,
 61			sf->rel_write_seq) ||
 62	    nla_put_u64_64bit(skb, MPTCP_SUBFLOW_ATTR_MAP_SEQ, sf->map_seq,
 63			      MPTCP_SUBFLOW_ATTR_PAD) ||
 64	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_MAP_SFSEQ,
 65			sf->map_subflow_seq) ||
 66	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_SSN_OFFSET, sf->ssn_offset) ||
 67	    nla_put_u16(skb, MPTCP_SUBFLOW_ATTR_MAP_DATALEN,
 68			sf->map_data_len) ||
 69	    nla_put_u32(skb, MPTCP_SUBFLOW_ATTR_FLAGS, flags) ||
 70	    nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_REM, sf->remote_id) ||
 71	    nla_put_u8(skb, MPTCP_SUBFLOW_ATTR_ID_LOC, subflow_get_local_id(sf))) {
 72		err = -EMSGSIZE;
 73		goto nla_failure;
 74	}
 75
 76	rcu_read_unlock();
 77	unlock_sock_fast(sk, slow);
 78	nla_nest_end(skb, start);
 79	return 0;
 80
 81nla_failure:
 82	rcu_read_unlock();
 83	unlock_sock_fast(sk, slow);
 84	nla_nest_cancel(skb, start);
 85	return err;
 86}
 87
 88static size_t subflow_get_info_size(const struct sock *sk)
 89{
 90	size_t size = 0;
 91
 92	size += nla_total_size(0) +	/* INET_ULP_INFO_MPTCP */
 93		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_TOKEN_REM */
 94		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_TOKEN_LOC */
 95		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */
 96		nla_total_size_64bit(8) +	/* MPTCP_SUBFLOW_ATTR_MAP_SEQ */
 97		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */
 98		nla_total_size(2) +	/* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
 99		nla_total_size(2) +	/* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */
100		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_FLAGS */
101		nla_total_size(1) +	/* MPTCP_SUBFLOW_ATTR_ID_REM */
102		nla_total_size(1) +	/* MPTCP_SUBFLOW_ATTR_ID_LOC */
103		0;
104	return size;
105}
106
107void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops)
108{
109	ops->get_info = subflow_get_info;
110	ops->get_info_size = subflow_get_info_size;
111}