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 struct nlattr *bc, bool net_admin) 19 { 20 if (!inet_diag_bc_sk(bc, 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 inet_diag_dump_data *cb_data = cb->data; 80 struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; 81 struct nlattr *bc = cb_data->inet_diag_nla_bc; 82 struct net *net = sock_net(skb->sk); 83 struct inet_hashinfo *hinfo; 84 int i; 85 86 hinfo = net->ipv4.tcp_death_row.hashinfo; 87 88 for (i = diag_ctx->l_slot; i <= hinfo->lhash2_mask; i++) { 89 struct inet_listen_hashbucket *ilb; 90 struct hlist_nulls_node *node; 91 struct sock *sk; 92 int num = 0; 93 94 ilb = &hinfo->lhash2[i]; 95 96 rcu_read_lock(); 97 spin_lock(&ilb->lock); 98 sk_nulls_for_each(sk, node, &ilb->nulls_head) { 99 const struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk); 100 struct inet_sock *inet = inet_sk(sk); 101 int ret; 102 103 if (num < diag_ctx->l_num) 104 goto next_listen; 105 106 if (!ctx || strcmp(inet_csk(sk)->icsk_ulp_ops->name, "mptcp")) 107 goto next_listen; 108 109 sk = ctx->conn; 110 if (!sk || !net_eq(sock_net(sk), net)) 111 goto next_listen; 112 113 if (r->sdiag_family != AF_UNSPEC && 114 sk->sk_family != r->sdiag_family) 115 goto next_listen; 116 117 if (r->id.idiag_sport != inet->inet_sport && 118 r->id.idiag_sport) 119 goto next_listen; 120 121 if (!refcount_inc_not_zero(&sk->sk_refcnt)) 122 goto next_listen; 123 124 ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin); 125 126 sock_put(sk); 127 128 if (ret < 0) { 129 spin_unlock(&ilb->lock); 130 rcu_read_unlock(); 131 diag_ctx->l_slot = i; 132 diag_ctx->l_num = num; 133 return; 134 } 135 diag_ctx->l_num = num + 1; 136 num = 0; 137 next_listen: 138 ++num; 139 } 140 spin_unlock(&ilb->lock); 141 rcu_read_unlock(); 142 143 cond_resched(); 144 diag_ctx->l_num = 0; 145 } 146 147 diag_ctx->l_num = 0; 148 diag_ctx->l_slot = i; 149 } 150 151 static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, 152 const struct inet_diag_req_v2 *r) 153 { 154 bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN); 155 struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; 156 struct net *net = sock_net(skb->sk); 157 struct inet_diag_dump_data *cb_data; 158 struct mptcp_sock *msk; 159 struct nlattr *bc; 160 161 BUILD_BUG_ON(sizeof(cb->ctx) < sizeof(*diag_ctx)); 162 163 cb_data = cb->data; 164 bc = cb_data->inet_diag_nla_bc; 165 166 while ((msk = mptcp_token_iter_next(net, &diag_ctx->s_slot, 167 &diag_ctx->s_num)) != NULL) { 168 struct inet_sock *inet = (struct inet_sock *)msk; 169 struct sock *sk = (struct sock *)msk; 170 int ret = 0; 171 172 if (!(r->idiag_states & (1 << sk->sk_state))) 173 goto next; 174 if (r->sdiag_family != AF_UNSPEC && 175 sk->sk_family != r->sdiag_family) 176 goto next; 177 if (r->id.idiag_sport != inet->inet_sport && 178 r->id.idiag_sport) 179 goto next; 180 if (r->id.idiag_dport != inet->inet_dport && 181 r->id.idiag_dport) 182 goto next; 183 184 ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin); 185 next: 186 sock_put(sk); 187 if (ret < 0) { 188 /* will retry on the same position */ 189 diag_ctx->s_num--; 190 break; 191 } 192 cond_resched(); 193 } 194 195 if ((r->idiag_states & TCPF_LISTEN) && r->id.idiag_dport == 0) 196 mptcp_diag_dump_listeners(skb, cb, r, net_admin); 197 } 198 199 static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r, 200 void *_info) 201 { 202 struct mptcp_sock *msk = mptcp_sk(sk); 203 struct mptcp_info *info = _info; 204 205 r->idiag_rqueue = sk_rmem_alloc_get(sk); 206 r->idiag_wqueue = sk_wmem_alloc_get(sk); 207 208 if (inet_sk_state_load(sk) == TCP_LISTEN) { 209 struct sock *lsk = READ_ONCE(msk->first); 210 211 if (lsk) { 212 /* override with settings from tcp listener, 213 * so Send-Q will show accept queue. 214 */ 215 r->idiag_rqueue = READ_ONCE(lsk->sk_ack_backlog); 216 r->idiag_wqueue = READ_ONCE(lsk->sk_max_ack_backlog); 217 } 218 } 219 220 if (!info) 221 return; 222 223 mptcp_diag_fill_info(msk, info); 224 } 225 226 static const struct inet_diag_handler mptcp_diag_handler = { 227 .owner = THIS_MODULE, 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(&mptcp_diag_handler); 238 } 239 240 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_DESCRIPTION("MPTCP socket monitoring via SOCK_DIAG"); 249 MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-262 /* AF_INET - IPPROTO_MPTCP */); 250