1 // SPDX-License-Identifier: GPL-2.0 2 /* MPTCP socket monitoring support 3 * 4 * Copyright (c) 2020 Red Hat 5 * 6 * Author: Paolo Abeni <pabeni@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 sk_diag_dump(struct sock *sk, struct sk_buff *skb, 16 struct netlink_callback *cb, 17 const struct inet_diag_req_v2 *req, 18 bool net_admin) 19 { 20 if (!inet_diag_bc_sk(cb->data, sk)) 21 return 0; 22 23 return inet_sk_diag_fill(sk, inet_csk(sk), skb, cb, req, NLM_F_MULTI, 24 net_admin); 25 } 26 27 static int mptcp_diag_dump_one(struct netlink_callback *cb, 28 const struct inet_diag_req_v2 *req) 29 { 30 struct sk_buff *in_skb = cb->skb; 31 struct mptcp_sock *msk = NULL; 32 struct sk_buff *rep; 33 int err = -ENOENT; 34 struct net *net; 35 struct sock *sk; 36 37 net = sock_net(in_skb->sk); 38 msk = mptcp_token_get_sock(net, req->id.idiag_cookie[0]); 39 if (!msk) 40 goto out_nosk; 41 42 err = -ENOMEM; 43 sk = (struct sock *)msk; 44 rep = nlmsg_new(nla_total_size(sizeof(struct inet_diag_msg)) + 45 inet_diag_msg_attrs_size() + 46 nla_total_size(sizeof(struct mptcp_info)) + 47 nla_total_size(sizeof(struct inet_diag_meminfo)) + 64, 48 GFP_KERNEL); 49 if (!rep) 50 goto out; 51 52 err = inet_sk_diag_fill(sk, inet_csk(sk), rep, cb, req, 0, 53 netlink_net_capable(in_skb, CAP_NET_ADMIN)); 54 if (err < 0) { 55 WARN_ON(err == -EMSGSIZE); 56 kfree_skb(rep); 57 goto out; 58 } 59 err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid); 60 61 out: 62 sock_put(sk); 63 64 out_nosk: 65 return err; 66 } 67 68 struct mptcp_diag_ctx { 69 long s_slot; 70 long s_num; 71 unsigned int l_slot; 72 unsigned int l_num; 73 }; 74 75 static void mptcp_diag_dump_listeners(struct sk_buff *skb, struct netlink_callback *cb, 76 const struct inet_diag_req_v2 *r, 77 bool net_admin) 78 { 79 struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; 80 struct net *net = sock_net(skb->sk); 81 struct inet_hashinfo *hinfo; 82 int i; 83 84 hinfo = net->ipv4.tcp_death_row.hashinfo; 85 86 for (i = diag_ctx->l_slot; i <= hinfo->lhash2_mask; i++) { 87 struct inet_listen_hashbucket *ilb; 88 struct hlist_nulls_node *node; 89 struct sock *sk; 90 int num = 0; 91 92 ilb = &hinfo->lhash2[i]; 93 94 rcu_read_lock(); 95 spin_lock(&ilb->lock); 96 sk_nulls_for_each(sk, node, &ilb->nulls_head) { 97 const struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk); 98 struct inet_sock *inet = inet_sk(sk); 99 int ret; 100 101 if (num < diag_ctx->l_num) 102 goto next_listen; 103 104 if (!ctx || strcmp(inet_csk(sk)->icsk_ulp_ops->name, "mptcp")) 105 goto next_listen; 106 107 sk = ctx->conn; 108 if (!sk || !net_eq(sock_net(sk), net)) 109 goto next_listen; 110 111 if (r->sdiag_family != AF_UNSPEC && 112 sk->sk_family != r->sdiag_family) 113 goto next_listen; 114 115 if (r->id.idiag_sport != inet->inet_sport && 116 r->id.idiag_sport) 117 goto next_listen; 118 119 if (!refcount_inc_not_zero(&sk->sk_refcnt)) 120 goto next_listen; 121 122 ret = sk_diag_dump(sk, skb, cb, r, net_admin); 123 124 sock_put(sk); 125 126 if (ret < 0) { 127 spin_unlock(&ilb->lock); 128 rcu_read_unlock(); 129 diag_ctx->l_slot = i; 130 diag_ctx->l_num = num; 131 return; 132 } 133 diag_ctx->l_num = num + 1; 134 num = 0; 135 next_listen: 136 ++num; 137 } 138 spin_unlock(&ilb->lock); 139 rcu_read_unlock(); 140 141 cond_resched(); 142 diag_ctx->l_num = 0; 143 } 144 145 diag_ctx->l_num = 0; 146 diag_ctx->l_slot = i; 147 } 148 149 static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, 150 const struct inet_diag_req_v2 *r) 151 { 152 bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN); 153 struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; 154 struct net *net = sock_net(skb->sk); 155 struct mptcp_sock *msk; 156 157 BUILD_BUG_ON(sizeof(cb->ctx) < sizeof(*diag_ctx)); 158 159 while ((msk = mptcp_token_iter_next(net, &diag_ctx->s_slot, 160 &diag_ctx->s_num)) != NULL) { 161 struct inet_sock *inet = (struct inet_sock *)msk; 162 struct sock *sk = (struct sock *)msk; 163 int ret = 0; 164 165 if (!(r->idiag_states & (1 << sk->sk_state))) 166 goto next; 167 if (r->sdiag_family != AF_UNSPEC && 168 sk->sk_family != r->sdiag_family) 169 goto next; 170 if (r->id.idiag_sport != inet->inet_sport && 171 r->id.idiag_sport) 172 goto next; 173 if (r->id.idiag_dport != inet->inet_dport && 174 r->id.idiag_dport) 175 goto next; 176 177 ret = sk_diag_dump(sk, skb, cb, r, net_admin); 178 next: 179 sock_put(sk); 180 if (ret < 0) { 181 /* will retry on the same position */ 182 diag_ctx->s_num--; 183 break; 184 } 185 cond_resched(); 186 } 187 188 if ((r->idiag_states & TCPF_LISTEN) && r->id.idiag_dport == 0) 189 mptcp_diag_dump_listeners(skb, cb, r, net_admin); 190 } 191 192 static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r, 193 void *_info) 194 { 195 struct mptcp_sock *msk = mptcp_sk(sk); 196 struct mptcp_info *info = _info; 197 198 r->idiag_rqueue = sk_rmem_alloc_get(sk); 199 r->idiag_wqueue = sk_wmem_alloc_get(sk); 200 201 if (inet_sk_state_load(sk) == TCP_LISTEN) { 202 struct sock *lsk = READ_ONCE(msk->first); 203 204 if (lsk) { 205 /* override with settings from tcp listener, 206 * so Send-Q will show accept queue. 207 */ 208 r->idiag_rqueue = READ_ONCE(lsk->sk_ack_backlog); 209 r->idiag_wqueue = READ_ONCE(lsk->sk_max_ack_backlog); 210 } 211 } 212 213 if (!info) 214 return; 215 216 mptcp_diag_fill_info(msk, info); 217 } 218 219 static const struct inet_diag_handler mptcp_diag_handler = { 220 .owner = THIS_MODULE, 221 .dump = mptcp_diag_dump, 222 .dump_one = mptcp_diag_dump_one, 223 .idiag_get_info = mptcp_diag_get_info, 224 .idiag_type = IPPROTO_MPTCP, 225 .idiag_info_size = sizeof(struct mptcp_info), 226 }; 227 228 static int __init mptcp_diag_init(void) 229 { 230 return inet_diag_register(&mptcp_diag_handler); 231 } 232 233 static void __exit mptcp_diag_exit(void) 234 { 235 inet_diag_unregister(&mptcp_diag_handler); 236 } 237 238 module_init(mptcp_diag_init); 239 module_exit(mptcp_diag_exit); 240 MODULE_LICENSE("GPL"); 241 MODULE_DESCRIPTION("MPTCP socket monitoring via SOCK_DIAG"); 242 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-262 /* AF_INET - IPPROTO_MPTCP */); 243