net/ipv4/tcp_diag.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * tcp_diag.c   Module for monitoring TCP transport protocols sockets.
   4  *
   5  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/net.h>
  10 #include <linux/sock_diag.h>
  11 #include <linux/inet_diag.h>
  12
  13 #include <linux/tcp.h>
  14
  15 #include <net/netlink.h>
  16 #include <net/tcp.h>
  17
  18 static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
  19                               void *_info)
  20 {
  21         struct tcp_info *info = _info;
  22
  23         if (inet_sk_state_load(sk) == TCP_LISTEN) {
  24                 r->idiag_rqueue = READ_ONCE(sk->sk_ack_backlog);
  25                 r->idiag_wqueue = READ_ONCE(sk->sk_max_ack_backlog);
  26         } else if (sk->sk_type == SOCK_STREAM) {
  27                 const struct tcp_sock *tp = tcp_sk(sk);
  28
  29                 r->idiag_rqueue = max_t(int, READ_ONCE(tp->rcv_nxt) -
  30                                              READ_ONCE(tp->copied_seq), 0);
  31                 r->idiag_wqueue = READ_ONCE(tp->write_seq) - tp->snd_una;
  32         }
  33         if (info)
  34                 tcp_get_info(sk, info);
  35 }
  36
  37 #ifdef CONFIG_TCP_MD5SIG
  38 static void tcp_diag_md5sig_fill(struct tcp_diag_md5sig *info,
  39                                  const struct tcp_md5sig_key *key)
  40 {
  41         info->tcpm_family = key->family;
  42         info->tcpm_prefixlen = key->prefixlen;
  43         info->tcpm_keylen = key->keylen;
  44         memcpy(info->tcpm_key, key->key, key->keylen);
  45
  46         if (key->family == AF_INET)
  47                 info->tcpm_addr[0] = key->addr.a4.s_addr;
  48         #if IS_ENABLED(CONFIG_IPV6)
  49         else if (key->family == AF_INET6)
  50                 memcpy(&info->tcpm_addr, &key->addr.a6,
  51                        sizeof(info->tcpm_addr));
  52         #endif
  53 }
  54
  55 static int tcp_diag_put_md5sig(struct sk_buff *skb,
  56                                const struct tcp_md5sig_info *md5sig)
  57 {
  58         const struct tcp_md5sig_key *key;
  59         struct tcp_diag_md5sig *info;
  60         struct nlattr *attr;
  61         int md5sig_count = 0;
  62
  63         hlist_for_each_entry_rcu(key, &md5sig->head, node)
  64                 md5sig_count++;
  65         if (md5sig_count == 0)
  66                 return 0;
  67
  68         attr = nla_reserve(skb, INET_DIAG_MD5SIG,
  69                            md5sig_count * sizeof(struct tcp_diag_md5sig));
  70         if (!attr)
  71                 return -EMSGSIZE;
  72
  73         info = nla_data(attr);
  74         memset(info, 0, md5sig_count * sizeof(struct tcp_diag_md5sig));
  75         hlist_for_each_entry_rcu(key, &md5sig->head, node) {
  76                 tcp_diag_md5sig_fill(info++, key);
  77                 if (--md5sig_count == 0)
  78                         break;
  79         }
  80
  81         return 0;
  82 }
  83 #endif
  84
  85 static int tcp_diag_put_ulp(struct sk_buff *skb, struct sock *sk,
  86                             const struct tcp_ulp_ops *ulp_ops)
  87 {
  88         struct nlattr *nest;
  89         int err;
  90
  91         nest = nla_nest_start_noflag(skb, INET_DIAG_ULP_INFO);
  92         if (!nest)
  93                 return -EMSGSIZE;
  94
  95         err = nla_put_string(skb, INET_ULP_INFO_NAME, ulp_ops->name);
  96         if (err)
  97                 goto nla_failure;
  98
  99         if (ulp_ops->get_info)
 100                 err = ulp_ops->get_info(sk, skb);
 101         if (err)
 102                 goto nla_failure;
 103
 104         nla_nest_end(skb, nest);
 105         return 0;
 106
 107 nla_failure:
 108         nla_nest_cancel(skb, nest);
 109         return err;
 110 }
 111
 112 static int tcp_diag_get_aux(struct sock *sk, bool net_admin,
 113                             struct sk_buff *skb)
 114 {
 115         struct inet_connection_sock *icsk = inet_csk(sk);
 116         int err = 0;
 117
 118 #ifdef CONFIG_TCP_MD5SIG
 119         if (net_admin) {
 120                 struct tcp_md5sig_info *md5sig;
 121
 122                 rcu_read_lock();
 123                 md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
 124                 if (md5sig)
 125                         err = tcp_diag_put_md5sig(skb, md5sig);
 126                 rcu_read_unlock();
 127                 if (err < 0)
 128                         return err;
 129         }
 130 #endif
 131
 132         if (net_admin) {
 133                 const struct tcp_ulp_ops *ulp_ops;
 134
 135                 ulp_ops = icsk->icsk_ulp_ops;
 136                 if (ulp_ops)
 137                         err = tcp_diag_put_ulp(skb, sk, ulp_ops);
 138                 if (err)
 139                         return err;
 140         }
 141         return 0;
 142 }
 143
 144 static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
 145 {
 146         struct inet_connection_sock *icsk = inet_csk(sk);
 147         size_t size = 0;
 148
 149 #ifdef CONFIG_TCP_MD5SIG
 150         if (net_admin && sk_fullsock(sk)) {
 151                 const struct tcp_md5sig_info *md5sig;
 152                 const struct tcp_md5sig_key *key;
 153                 size_t md5sig_count = 0;
 154
 155                 rcu_read_lock();
 156                 md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
 157                 if (md5sig) {
 158                         hlist_for_each_entry_rcu(key, &md5sig->head, node)
 159                                 md5sig_count++;
 160                 }
 161                 rcu_read_unlock();
 162                 size += nla_total_size(md5sig_count *
 163                                        sizeof(struct tcp_diag_md5sig));
 164         }
 165 #endif
 166
 167         if (net_admin && sk_fullsock(sk)) {
 168                 const struct tcp_ulp_ops *ulp_ops;
 169
 170                 ulp_ops = icsk->icsk_ulp_ops;
 171                 if (ulp_ops) {
 172                         size += nla_total_size(0) +
 173                                 nla_total_size(TCP_ULP_NAME_MAX);
 174                         if (ulp_ops->get_info_size)
 175                                 size += ulp_ops->get_info_size(sk);
 176                 }
 177         }
 178         return size;
 179 }
 180
 181 static void tcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 182                           const struct inet_diag_req_v2 *r)
 183 {
 184         struct inet_hashinfo *hinfo;
 185
 186         hinfo = sock_net(cb->skb->sk)->ipv4.tcp_death_row.hashinfo;
 187
 188         inet_diag_dump_icsk(hinfo, skb, cb, r);
 189 }
 190
 191 static int tcp_diag_dump_one(struct netlink_callback *cb,
 192                              const struct inet_diag_req_v2 *req)
 193 {
 194         struct inet_hashinfo *hinfo;
 195
 196         hinfo = sock_net(cb->skb->sk)->ipv4.tcp_death_row.hashinfo;
 197
 198         return inet_diag_dump_one_icsk(hinfo, cb, req);
 199 }
 200
 201 #ifdef CONFIG_INET_DIAG_DESTROY
 202 static int tcp_diag_destroy(struct sk_buff *in_skb,
 203                             const struct inet_diag_req_v2 *req)
 204 {
 205         struct net *net = sock_net(in_skb->sk);
 206         struct inet_hashinfo *hinfo;
 207         struct sock *sk;
 208         int err;
 209
 210         hinfo = net->ipv4.tcp_death_row.hashinfo;
 211         sk = inet_diag_find_one_icsk(net, hinfo, req);
 212
 213         if (IS_ERR(sk))
 214                 return PTR_ERR(sk);
 215
 216         err = sock_diag_destroy(sk, ECONNABORTED);
 217
 218         sock_gen_put(sk);
 219
 220         return err;
 221 }
 222 #endif
 223
 224 static const struct inet_diag_handler tcp_diag_handler = {
 225         .owner                  = THIS_MODULE,
 226         .dump                   = tcp_diag_dump,
 227         .dump_one               = tcp_diag_dump_one,
 228         .idiag_get_info         = tcp_diag_get_info,
 229         .idiag_get_aux          = tcp_diag_get_aux,
 230         .idiag_get_aux_size     = tcp_diag_get_aux_size,
 231         .idiag_type             = IPPROTO_TCP,
 232         .idiag_info_size        = sizeof(struct tcp_info),
 233 #ifdef CONFIG_INET_DIAG_DESTROY
 234         .destroy                = tcp_diag_destroy,
 235 #endif
 236 };
 237
 238 static int __init tcp_diag_init(void)
 239 {
 240         return inet_diag_register(&tcp_diag_handler);
 241 }
 242
 243 static void __exit tcp_diag_exit(void)
 244 {
 245         inet_diag_unregister(&tcp_diag_handler);
 246 }
 247
 248 module_init(tcp_diag_init);
 249 module_exit(tcp_diag_exit);
 250 MODULE_LICENSE("GPL");
 251 MODULE_DESCRIPTION("TCP socket monitoring via SOCK_DIAG");
 252 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);