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 | |
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: bc, sk)) |
22 | return 0; |
23 | |
24 | return inet_sk_diag_fill(sk, icsk: inet_csk(sk), skb, cb, req, NLM_F_MULTI, |
25 | net_admin); |
26 | } |
27 | |
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(sk: in_skb->sk); |
39 | msk = mptcp_token_get_sock(net, token: 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(payload: nla_total_size(payload: sizeof(struct inet_diag_msg)) + |
46 | inet_diag_msg_attrs_size() + |
47 | nla_total_size(payload: sizeof(struct mptcp_info)) + |
48 | nla_total_size(payload: sizeof(struct inet_diag_meminfo)) + 64, |
49 | GFP_KERNEL); |
50 | if (!rep) |
51 | goto out; |
52 | |
53 | err = inet_sk_diag_fill(sk, icsk: inet_csk(sk), skb: rep, cb, req, nlmsg_flags: 0, |
54 | net_admin: netlink_net_capable(skb: in_skb, CAP_NET_ADMIN)); |
55 | if (err < 0) { |
56 | WARN_ON(err == -EMSGSIZE); |
57 | kfree_skb(skb: rep); |
58 | goto out; |
59 | } |
60 | err = nlmsg_unicast(sk: net->diag_nlsk, skb: 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 | |
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(sk: 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(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(net1: sock_net(sk), net2: 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(r: &sk->sk_refcnt)) |
123 | goto next_listen; |
124 | |
125 | ret = sk_diag_dump(sk, skb, cb, req: r, bc, net_admin); |
126 | |
127 | sock_put(sk); |
128 | |
129 | if (ret < 0) { |
130 | spin_unlock(lock: &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(lock: &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 | |
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(skb: cb->skb, CAP_NET_ADMIN); |
156 | struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; |
157 | struct net *net = sock_net(sk: 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, s_slot: &diag_ctx->s_slot, |
168 | s_num: &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, req: 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 | |
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 | |
235 | static int __init mptcp_diag_init(void) |
236 | { |
237 | return inet_diag_register(handler: &mptcp_diag_handler); |
238 | } |
239 | |
240 | static void __exit mptcp_diag_exit(void) |
241 | { |
242 | inet_diag_unregister(handler: &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 | |