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 = sk->sk_ack_backlog;
  25                 r->idiag_wqueue = 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, tp->rcv_nxt - tp->copied_seq, 0);
  30                 r->idiag_wqueue = tp->write_seq - tp->snd_una;
  31         }
  32         if (info)
  33                 tcp_get_info(sk, info);
  34 }
  35
  36 #ifdef CONFIG_TCP_MD5SIG
  37 static void tcp_diag_md5sig_fill(struct tcp_diag_md5sig *info,
  38                                  const struct tcp_md5sig_key *key)
  39 {
  40         info->tcpm_family = key->family;
  41         info->tcpm_prefixlen = key->prefixlen;
  42         info->tcpm_keylen = key->keylen;
  43         memcpy(info->tcpm_key, key->key, key->keylen);
  44
  45         if (key->family == AF_INET)
  46                 info->tcpm_addr[0] = key->addr.a4.s_addr;
  47         #if IS_ENABLED(CONFIG_IPV6)
  48         else if (key->family == AF_INET6)
  49                 memcpy(&info->tcpm_addr, &key->addr.a6,
  50                        sizeof(info->tcpm_addr));
  51         #endif
  52 }
  53
  54 static int tcp_diag_put_md5sig(struct sk_buff *skb,
  55                                const struct tcp_md5sig_info *md5sig)
  56 {
  57         const struct tcp_md5sig_key *key;
  58         struct tcp_diag_md5sig *info;
  59         struct nlattr *attr;
  60         int md5sig_count = 0;
  61
  62         hlist_for_each_entry_rcu(key, &md5sig->head, node)
  63                 md5sig_count++;
  64         if (md5sig_count == 0)
  65                 return 0;
  66
  67         attr = nla_reserve(skb, INET_DIAG_MD5SIG,
  68                            md5sig_count * sizeof(struct tcp_diag_md5sig));
  69         if (!attr)
  70                 return -EMSGSIZE;
  71
  72         info = nla_data(attr);
  73         memset(info, 0, md5sig_count * sizeof(struct tcp_diag_md5sig));
  74         hlist_for_each_entry_rcu(key, &md5sig->head, node) {
  75                 tcp_diag_md5sig_fill(info++, key);
  76                 if (--md5sig_count == 0)
  77                         break;
  78         }
  79
  80         return 0;
  81 }
  82 #endif
  83
  84 static int tcp_diag_get_aux(struct sock *sk, bool net_admin,
  85                             struct sk_buff *skb)
  86 {
  87 #ifdef CONFIG_TCP_MD5SIG
  88         if (net_admin) {
  89                 struct tcp_md5sig_info *md5sig;
  90                 int err = 0;
  91
  92                 rcu_read_lock();
  93                 md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
  94                 if (md5sig)
  95                         err = tcp_diag_put_md5sig(skb, md5sig);
  96                 rcu_read_unlock();
  97                 if (err < 0)
  98                         return err;
  99         }
 100 #endif
 101
 102         return 0;
 103 }
 104
 105 static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
 106 {
 107         size_t size = 0;
 108
 109 #ifdef CONFIG_TCP_MD5SIG
 110         if (net_admin && sk_fullsock(sk)) {
 111                 const struct tcp_md5sig_info *md5sig;
 112                 const struct tcp_md5sig_key *key;
 113                 size_t md5sig_count = 0;
 114
 115                 rcu_read_lock();
 116                 md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
 117                 if (md5sig) {
 118                         hlist_for_each_entry_rcu(key, &md5sig->head, node)
 119                                 md5sig_count++;
 120                 }
 121                 rcu_read_unlock();
 122                 size += nla_total_size(md5sig_count *
 123                                        sizeof(struct tcp_diag_md5sig));
 124         }
 125 #endif
 126
 127         return size;
 128 }
 129
 130 static void tcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 131                           const struct inet_diag_req_v2 *r, struct nlattr *bc)
 132 {
 133         inet_diag_dump_icsk(&tcp_hashinfo, skb, cb, r, bc);
 134 }
 135
 136 static int tcp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,
 137                              const struct inet_diag_req_v2 *req)
 138 {
 139         return inet_diag_dump_one_icsk(&tcp_hashinfo, in_skb, nlh, req);
 140 }
 141
 142 #ifdef CONFIG_INET_DIAG_DESTROY
 143 static int tcp_diag_destroy(struct sk_buff *in_skb,
 144                             const struct inet_diag_req_v2 *req)
 145 {
 146         struct net *net = sock_net(in_skb->sk);
 147         struct sock *sk = inet_diag_find_one_icsk(net, &tcp_hashinfo, req);
 148         int err;
 149
 150         if (IS_ERR(sk))
 151                 return PTR_ERR(sk);
 152
 153         err = sock_diag_destroy(sk, ECONNABORTED);
 154
 155         sock_gen_put(sk);
 156
 157         return err;
 158 }
 159 #endif
 160
 161 static const struct inet_diag_handler tcp_diag_handler = {
 162         .dump                   = tcp_diag_dump,
 163         .dump_one               = tcp_diag_dump_one,
 164         .idiag_get_info         = tcp_diag_get_info,
 165         .idiag_get_aux          = tcp_diag_get_aux,
 166         .idiag_get_aux_size     = tcp_diag_get_aux_size,
 167         .idiag_type             = IPPROTO_TCP,
 168         .idiag_info_size        = sizeof(struct tcp_info),
 169 #ifdef CONFIG_INET_DIAG_DESTROY
 170         .destroy                = tcp_diag_destroy,
 171 #endif
 172 };
 173
 174 static int __init tcp_diag_init(void)
 175 {
 176         return inet_diag_register(&tcp_diag_handler);
 177 }
 178
 179 static void __exit tcp_diag_exit(void)
 180 {
 181         inet_diag_unregister(&tcp_diag_handler);
 182 }
 183
 184 module_init(tcp_diag_init);
 185 module_exit(tcp_diag_exit);
 186 MODULE_LICENSE("GPL");
 187 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);