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 (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, 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(4) +	/* 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}