xref: /openbmc/linux/net/mptcp/mptcp_diag.c (revision 4461568a)
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 <uapi/linux/mptcp.h>
14 #include "protocol.h"
15 
sk_diag_dump(struct sock * sk,struct sk_buff * skb,struct netlink_callback * cb,const struct inet_diag_req_v2 * req,struct nlattr * bc,bool net_admin)16 static int sk_diag_dump(struct sock *sk, struct sk_buff *skb,
17 			struct netlink_callback *cb,
18 			const struct inet_diag_req_v2 *req,
19 			struct nlattr *bc, bool net_admin)
20 {
21 	if (!inet_diag_bc_sk(bc, sk))
22 		return 0;
23 
24 	return inet_sk_diag_fill(sk, inet_csk(sk), skb, cb, req, NLM_F_MULTI,
25 				 net_admin);
26 }
27 
mptcp_diag_dump_one(struct netlink_callback * cb,const struct inet_diag_req_v2 * req)28 static int mptcp_diag_dump_one(struct netlink_callback *cb,
29 			       const struct inet_diag_req_v2 *req)
30 {
31 	struct sk_buff *in_skb = cb->skb;
32 	struct mptcp_sock *msk = NULL;
33 	struct sk_buff *rep;
34 	int err = -ENOENT;
35 	struct net *net;
36 	struct sock *sk;
37 
38 	net = sock_net(in_skb->sk);
39 	msk = mptcp_token_get_sock(net, req->id.idiag_cookie[0]);
40 	if (!msk)
41 		goto out_nosk;
42 
43 	err = -ENOMEM;
44 	sk = (struct sock *)msk;
45 	rep = nlmsg_new(nla_total_size(sizeof(struct inet_diag_msg)) +
46 			inet_diag_msg_attrs_size() +
47 			nla_total_size(sizeof(struct mptcp_info)) +
48 			nla_total_size(sizeof(struct inet_diag_meminfo)) + 64,
49 			GFP_KERNEL);
50 	if (!rep)
51 		goto out;
52 
53 	err = inet_sk_diag_fill(sk, inet_csk(sk), rep, cb, req, 0,
54 				netlink_net_capable(in_skb, CAP_NET_ADMIN));
55 	if (err < 0) {
56 		WARN_ON(err == -EMSGSIZE);
57 		kfree_skb(rep);
58 		goto out;
59 	}
60 	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
61 
62 out:
63 	sock_put(sk);
64 
65 out_nosk:
66 	return err;
67 }
68 
69 struct mptcp_diag_ctx {
70 	long s_slot;
71 	long s_num;
72 	unsigned int l_slot;
73 	unsigned int l_num;
74 };
75 
mptcp_diag_dump_listeners(struct sk_buff * skb,struct netlink_callback * cb,const struct inet_diag_req_v2 * r,bool net_admin)76 static void mptcp_diag_dump_listeners(struct sk_buff *skb, struct netlink_callback *cb,
77 				      const struct inet_diag_req_v2 *r,
78 				      bool net_admin)
79 {
80 	struct inet_diag_dump_data *cb_data = cb->data;
81 	struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx;
82 	struct nlattr *bc = cb_data->inet_diag_nla_bc;
83 	struct net *net = sock_net(skb->sk);
84 	struct inet_hashinfo *hinfo;
85 	int i;
86 
87 	hinfo = net->ipv4.tcp_death_row.hashinfo;
88 
89 	for (i = diag_ctx->l_slot; i <= hinfo->lhash2_mask; i++) {
90 		struct inet_listen_hashbucket *ilb;
91 		struct hlist_nulls_node *node;
92 		struct sock *sk;
93 		int num = 0;
94 
95 		ilb = &hinfo->lhash2[i];
96 
97 		rcu_read_lock();
98 		spin_lock(&ilb->lock);
99 		sk_nulls_for_each(sk, node, &ilb->nulls_head) {
100 			const struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk);
101 			struct inet_sock *inet = inet_sk(sk);
102 			int ret;
103 
104 			if (num < diag_ctx->l_num)
105 				goto next_listen;
106 
107 			if (!ctx || strcmp(inet_csk(sk)->icsk_ulp_ops->name, "mptcp"))
108 				goto next_listen;
109 
110 			sk = ctx->conn;
111 			if (!sk || !net_eq(sock_net(sk), net))
112 				goto next_listen;
113 
114 			if (r->sdiag_family != AF_UNSPEC &&
115 			    sk->sk_family != r->sdiag_family)
116 				goto next_listen;
117 
118 			if (r->id.idiag_sport != inet->inet_sport &&
119 			    r->id.idiag_sport)
120 				goto next_listen;
121 
122 			if (!refcount_inc_not_zero(&sk->sk_refcnt))
123 				goto next_listen;
124 
125 			ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin);
126 
127 			sock_put(sk);
128 
129 			if (ret < 0) {
130 				spin_unlock(&ilb->lock);
131 				rcu_read_unlock();
132 				diag_ctx->l_slot = i;
133 				diag_ctx->l_num = num;
134 				return;
135 			}
136 			diag_ctx->l_num = num + 1;
137 			num = 0;
138 next_listen:
139 			++num;
140 		}
141 		spin_unlock(&ilb->lock);
142 		rcu_read_unlock();
143 
144 		cond_resched();
145 		diag_ctx->l_num = 0;
146 	}
147 
148 	diag_ctx->l_num = 0;
149 	diag_ctx->l_slot = i;
150 }
151 
mptcp_diag_dump(struct sk_buff * skb,struct netlink_callback * cb,const struct inet_diag_req_v2 * r)152 static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
153 			    const struct inet_diag_req_v2 *r)
154 {
155 	bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
156 	struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx;
157 	struct net *net = sock_net(skb->sk);
158 	struct inet_diag_dump_data *cb_data;
159 	struct mptcp_sock *msk;
160 	struct nlattr *bc;
161 
162 	BUILD_BUG_ON(sizeof(cb->ctx) < sizeof(*diag_ctx));
163 
164 	cb_data = cb->data;
165 	bc = cb_data->inet_diag_nla_bc;
166 
167 	while ((msk = mptcp_token_iter_next(net, &diag_ctx->s_slot,
168 					    &diag_ctx->s_num)) != NULL) {
169 		struct inet_sock *inet = (struct inet_sock *)msk;
170 		struct sock *sk = (struct sock *)msk;
171 		int ret = 0;
172 
173 		if (!(r->idiag_states & (1 << sk->sk_state)))
174 			goto next;
175 		if (r->sdiag_family != AF_UNSPEC &&
176 		    sk->sk_family != r->sdiag_family)
177 			goto next;
178 		if (r->id.idiag_sport != inet->inet_sport &&
179 		    r->id.idiag_sport)
180 			goto next;
181 		if (r->id.idiag_dport != inet->inet_dport &&
182 		    r->id.idiag_dport)
183 			goto next;
184 
185 		ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin);
186 next:
187 		sock_put(sk);
188 		if (ret < 0) {
189 			/* will retry on the same position */
190 			diag_ctx->s_num--;
191 			break;
192 		}
193 		cond_resched();
194 	}
195 
196 	if ((r->idiag_states & TCPF_LISTEN) && r->id.idiag_dport == 0)
197 		mptcp_diag_dump_listeners(skb, cb, r, net_admin);
198 }
199 
mptcp_diag_get_info(struct sock * sk,struct inet_diag_msg * r,void * _info)200 static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
201 				void *_info)
202 {
203 	struct mptcp_sock *msk = mptcp_sk(sk);
204 	struct mptcp_info *info = _info;
205 
206 	r->idiag_rqueue = sk_rmem_alloc_get(sk);
207 	r->idiag_wqueue = sk_wmem_alloc_get(sk);
208 
209 	if (inet_sk_state_load(sk) == TCP_LISTEN) {
210 		struct sock *lsk = READ_ONCE(msk->first);
211 
212 		if (lsk) {
213 			/* override with settings from tcp listener,
214 			 * so Send-Q will show accept queue.
215 			 */
216 			r->idiag_rqueue = READ_ONCE(lsk->sk_ack_backlog);
217 			r->idiag_wqueue = READ_ONCE(lsk->sk_max_ack_backlog);
218 		}
219 	}
220 
221 	if (!info)
222 		return;
223 
224 	mptcp_diag_fill_info(msk, info);
225 }
226 
227 static const struct inet_diag_handler mptcp_diag_handler = {
228 	.dump		 = mptcp_diag_dump,
229 	.dump_one	 = mptcp_diag_dump_one,
230 	.idiag_get_info  = mptcp_diag_get_info,
231 	.idiag_type	 = IPPROTO_MPTCP,
232 	.idiag_info_size = sizeof(struct mptcp_info),
233 };
234 
mptcp_diag_init(void)235 static int __init mptcp_diag_init(void)
236 {
237 	return inet_diag_register(&mptcp_diag_handler);
238 }
239 
mptcp_diag_exit(void)240 static void __exit mptcp_diag_exit(void)
241 {
242 	inet_diag_unregister(&mptcp_diag_handler);
243 }
244 
245 module_init(mptcp_diag_init);
246 module_exit(mptcp_diag_exit);
247 MODULE_LICENSE("GPL");
248 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-262 /* AF_INET - IPPROTO_MPTCP */);
249