net/mptcp/diag.c

   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
  15 static 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
  80 nla_failure:
  81         rcu_read_unlock();
  82         unlock_sock_fast(sk, slow);
  83         nla_nest_cancel(skb, start);
  84         return err;
  85 }
  86
  87 static 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
 106 void 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 }