net/ipv4/tcp_diag.c

   1 /*
   2  * tcp_diag.c   Module for monitoring TCP transport protocols sockets.
   3  *
   4  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/net.h>
  14 #include <linux/sock_diag.h>
  15 #include <linux/inet_diag.h>
  16
  17 #include <linux/tcp.h>
  18
  19 #include <net/netlink.h>
  20 #include <net/tcp.h>
  21
  22 static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
  23                               void *_info)
  24 {
  25         struct tcp_info *info = _info;
  26
  27         if (sk_state_load(sk) == TCP_LISTEN) {
  28                 r->idiag_rqueue = sk->sk_ack_backlog;
  29                 r->idiag_wqueue = sk->sk_max_ack_backlog;
  30         } else if (sk->sk_type == SOCK_STREAM) {
  31                 const struct tcp_sock *tp = tcp_sk(sk);
  32
  33                 r->idiag_rqueue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
  34                 r->idiag_wqueue = tp->write_seq - tp->snd_una;
  35         }
  36         if (info)
  37                 tcp_get_info(sk, info);
  38 }
  39
  40 #ifdef CONFIG_TCP_MD5SIG
  41 static void tcp_diag_md5sig_fill(struct tcp_diag_md5sig *info,
  42                                  const struct tcp_md5sig_key *key)
  43 {
  44         info->tcpm_family = key->family;
  45         info->tcpm_prefixlen = key->prefixlen;
  46         info->tcpm_keylen = key->keylen;
  47         memcpy(info->tcpm_key, key->key, key->keylen);
  48
  49         if (key->family == AF_INET)
  50                 info->tcpm_addr[0] = key->addr.a4.s_addr;
  51         #if IS_ENABLED(CONFIG_IPV6)
  52         else if (key->family == AF_INET6)
  53                 memcpy(&info->tcpm_addr, &key->addr.a6,
  54                        sizeof(info->tcpm_addr));
  55         #endif
  56 }
  57
  58 static int tcp_diag_put_md5sig(struct sk_buff *skb,
  59                                const struct tcp_md5sig_info *md5sig)
  60 {
  61         const struct tcp_md5sig_key *key;
  62         struct tcp_diag_md5sig *info;
  63         struct nlattr *attr;
  64         int md5sig_count = 0;
  65
  66         hlist_for_each_entry_rcu(key, &md5sig->head, node)
  67                 md5sig_count++;
  68         if (md5sig_count == 0)
  69                 return 0;
  70
  71         attr = nla_reserve(skb, INET_DIAG_MD5SIG,
  72                            md5sig_count * sizeof(struct tcp_diag_md5sig));
  73         if (!attr)
  74                 return -EMSGSIZE;
  75
  76         info = nla_data(attr);
  77         memset(info, 0, md5sig_count * sizeof(struct tcp_diag_md5sig));
  78         hlist_for_each_entry_rcu(key, &md5sig->head, node) {
  79                 tcp_diag_md5sig_fill(info++, key);
  80                 if (--md5sig_count == 0)
  81                         break;
  82         }
  83
  84         return 0;
  85 }
  86 #endif
  87
  88 static int tcp_diag_get_aux(struct sock *sk, bool net_admin,
  89                             struct sk_buff *skb)
  90 {
  91 #ifdef CONFIG_TCP_MD5SIG
  92         if (net_admin) {
  93                 struct tcp_md5sig_info *md5sig;
  94                 int err = 0;
  95
  96                 rcu_read_lock();
  97                 md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
  98                 if (md5sig)
  99                         err = tcp_diag_put_md5sig(skb, md5sig);
 100                 rcu_read_unlock();
 101                 if (err < 0)
 102                         return err;
 103         }
 104 #endif
 105
 106         return 0;
 107 }
 108
 109 static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
 110 {
 111         size_t size = 0;
 112
 113 #ifdef CONFIG_TCP_MD5SIG
 114         if (net_admin && sk_fullsock(sk)) {
 115                 const struct tcp_md5sig_info *md5sig;
 116                 const struct tcp_md5sig_key *key;
 117                 size_t md5sig_count = 0;
 118
 119                 rcu_read_lock();
 120                 md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
 121                 if (md5sig) {
 122                         hlist_for_each_entry_rcu(key, &md5sig->head, node)
 123                                 md5sig_count++;
 124                 }
 125                 rcu_read_unlock();
 126                 size += nla_total_size(md5sig_count *
 127                                        sizeof(struct tcp_diag_md5sig));
 128         }
 129 #endif
 130
 131         return size;
 132 }
 133
 134 static void tcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 135                           const struct inet_diag_req_v2 *r, struct nlattr *bc)
 136 {
 137         inet_diag_dump_icsk(&tcp_hashinfo, skb, cb, r, bc);
 138 }
 139
 140 static int tcp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
 141                              const struct inet_diag_req_v2 *req)
 142 {
 143         return inet_diag_dump_one_icsk(&tcp_hashinfo, in_skb, nlh, req);
 144 }
 145
 146 #ifdef CONFIG_INET_DIAG_DESTROY
 147 static int tcp_diag_destroy(struct sk_buff *in_skb,
 148                             const struct inet_diag_req_v2 *req)
 149 {
 150         struct net *net = sock_net(in_skb->sk);
 151         struct sock *sk = inet_diag_find_one_icsk(net, &tcp_hashinfo, req);
 152         int err;
 153
 154         if (IS_ERR(sk))
 155                 return PTR_ERR(sk);
 156
 157         err = sock_diag_destroy(sk, ECONNABORTED);
 158
 159         sock_gen_put(sk);
 160
 161         return err;
 162 }
 163 #endif
 164
 165 static const struct inet_diag_handler tcp_diag_handler = {
 166         .dump                   = tcp_diag_dump,
 167         .dump_one               = tcp_diag_dump_one,
 168         .idiag_get_info         = tcp_diag_get_info,
 169         .idiag_get_aux          = tcp_diag_get_aux,
 170         .idiag_get_aux_size     = tcp_diag_get_aux_size,
 171         .idiag_type             = IPPROTO_TCP,
 172         .idiag_info_size        = sizeof(struct tcp_info),
 173 #ifdef CONFIG_INET_DIAG_DESTROY
 174         .destroy                = tcp_diag_destroy,
 175 #endif
 176 };
 177
 178 static int __init tcp_diag_init(void)
 179 {
 180         return inet_diag_register(&tcp_diag_handler);
 181 }
 182
 183 static void __exit tcp_diag_exit(void)
 184 {
 185         inet_diag_unregister(&tcp_diag_handler);
 186 }
 187
 188 module_init(tcp_diag_init);
 189 module_exit(tcp_diag_exit);
 190 MODULE_LICENSE("GPL");
 191 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);