| // SPDX-License-Identifier: GPL-2.0 |
| /* MPTCP socket monitoring support |
| * |
| * Copyright (c) 2020 Red Hat |
| * |
| * Author: Paolo Abeni <pabeni@redhat.com> |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/net.h> |
| #include <linux/inet_diag.h> |
| #include <net/netlink.h> |
| #include <uapi/linux/mptcp.h> |
| #include "protocol.h" |
| |
| static int 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) |
| { |
| if (!inet_diag_bc_sk(bc, sk)) |
| return 0; |
| |
| return inet_sk_diag_fill(sk, inet_csk(sk), skb, cb, req, NLM_F_MULTI, |
| net_admin); |
| } |
| |
| static int mptcp_diag_dump_one(struct netlink_callback *cb, |
| const struct inet_diag_req_v2 *req) |
| { |
| struct sk_buff *in_skb = cb->skb; |
| struct mptcp_sock *msk = NULL; |
| struct sk_buff *rep; |
| int err = -ENOENT; |
| struct net *net; |
| struct sock *sk; |
| |
| net = sock_net(in_skb->sk); |
| msk = mptcp_token_get_sock(net, req->id.idiag_cookie[0]); |
| if (!msk) |
| goto out_nosk; |
| |
| err = -ENOMEM; |
| sk = (struct sock *)msk; |
| rep = nlmsg_new(nla_total_size(sizeof(struct inet_diag_msg)) + |
| inet_diag_msg_attrs_size() + |
| nla_total_size(sizeof(struct mptcp_info)) + |
| nla_total_size(sizeof(struct inet_diag_meminfo)) + 64, |
| GFP_KERNEL); |
| if (!rep) |
| goto out; |
| |
| err = inet_sk_diag_fill(sk, inet_csk(sk), rep, cb, req, 0, |
| netlink_net_capable(in_skb, CAP_NET_ADMIN)); |
| if (err < 0) { |
| WARN_ON(err == -EMSGSIZE); |
| kfree_skb(rep); |
| goto out; |
| } |
| err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid); |
| |
| out: |
| sock_put(sk); |
| |
| out_nosk: |
| return err; |
| } |
| |
| struct mptcp_diag_ctx { |
| long s_slot; |
| long s_num; |
| unsigned int l_slot; |
| unsigned int l_num; |
| }; |
| |
| static void mptcp_diag_dump_listeners(struct sk_buff *skb, struct netlink_callback *cb, |
| const struct inet_diag_req_v2 *r, |
| bool net_admin) |
| { |
| struct inet_diag_dump_data *cb_data = cb->data; |
| struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; |
| struct nlattr *bc = cb_data->inet_diag_nla_bc; |
| struct net *net = sock_net(skb->sk); |
| struct inet_hashinfo *hinfo; |
| int i; |
| |
| hinfo = net->ipv4.tcp_death_row.hashinfo; |
| |
| for (i = diag_ctx->l_slot; i <= hinfo->lhash2_mask; i++) { |
| struct inet_listen_hashbucket *ilb; |
| struct hlist_nulls_node *node; |
| struct sock *sk; |
| int num = 0; |
| |
| ilb = &hinfo->lhash2[i]; |
| |
| rcu_read_lock(); |
| spin_lock(&ilb->lock); |
| sk_nulls_for_each(sk, node, &ilb->nulls_head) { |
| const struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk); |
| struct inet_sock *inet = inet_sk(sk); |
| int ret; |
| |
| if (num < diag_ctx->l_num) |
| goto next_listen; |
| |
| if (!ctx || strcmp(inet_csk(sk)->icsk_ulp_ops->name, "mptcp")) |
| goto next_listen; |
| |
| sk = ctx->conn; |
| if (!sk || !net_eq(sock_net(sk), net)) |
| goto next_listen; |
| |
| if (r->sdiag_family != AF_UNSPEC && |
| sk->sk_family != r->sdiag_family) |
| goto next_listen; |
| |
| if (r->id.idiag_sport != inet->inet_sport && |
| r->id.idiag_sport) |
| goto next_listen; |
| |
| if (!refcount_inc_not_zero(&sk->sk_refcnt)) |
| goto next_listen; |
| |
| ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin); |
| |
| sock_put(sk); |
| |
| if (ret < 0) { |
| spin_unlock(&ilb->lock); |
| rcu_read_unlock(); |
| diag_ctx->l_slot = i; |
| diag_ctx->l_num = num; |
| return; |
| } |
| diag_ctx->l_num = num + 1; |
| num = 0; |
| next_listen: |
| ++num; |
| } |
| spin_unlock(&ilb->lock); |
| rcu_read_unlock(); |
| |
| cond_resched(); |
| diag_ctx->l_num = 0; |
| } |
| |
| diag_ctx->l_num = 0; |
| diag_ctx->l_slot = i; |
| } |
| |
| static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, |
| const struct inet_diag_req_v2 *r) |
| { |
| bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN); |
| struct mptcp_diag_ctx *diag_ctx = (void *)cb->ctx; |
| struct net *net = sock_net(skb->sk); |
| struct inet_diag_dump_data *cb_data; |
| struct mptcp_sock *msk; |
| struct nlattr *bc; |
| |
| BUILD_BUG_ON(sizeof(cb->ctx) < sizeof(*diag_ctx)); |
| |
| cb_data = cb->data; |
| bc = cb_data->inet_diag_nla_bc; |
| |
| while ((msk = mptcp_token_iter_next(net, &diag_ctx->s_slot, |
| &diag_ctx->s_num)) != NULL) { |
| struct inet_sock *inet = (struct inet_sock *)msk; |
| struct sock *sk = (struct sock *)msk; |
| int ret = 0; |
| |
| if (!(r->idiag_states & (1 << sk->sk_state))) |
| goto next; |
| if (r->sdiag_family != AF_UNSPEC && |
| sk->sk_family != r->sdiag_family) |
| goto next; |
| if (r->id.idiag_sport != inet->inet_sport && |
| r->id.idiag_sport) |
| goto next; |
| if (r->id.idiag_dport != inet->inet_dport && |
| r->id.idiag_dport) |
| goto next; |
| |
| ret = sk_diag_dump(sk, skb, cb, r, bc, net_admin); |
| next: |
| sock_put(sk); |
| if (ret < 0) { |
| /* will retry on the same position */ |
| diag_ctx->s_num--; |
| break; |
| } |
| cond_resched(); |
| } |
| |
| if ((r->idiag_states & TCPF_LISTEN) && r->id.idiag_dport == 0) |
| mptcp_diag_dump_listeners(skb, cb, r, net_admin); |
| } |
| |
| static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r, |
| void *_info) |
| { |
| struct mptcp_sock *msk = mptcp_sk(sk); |
| struct mptcp_info *info = _info; |
| |
| r->idiag_rqueue = sk_rmem_alloc_get(sk); |
| r->idiag_wqueue = sk_wmem_alloc_get(sk); |
| |
| if (inet_sk_state_load(sk) == TCP_LISTEN) { |
| struct sock *lsk = READ_ONCE(msk->first); |
| |
| if (lsk) { |
| /* override with settings from tcp listener, |
| * so Send-Q will show accept queue. |
| */ |
| r->idiag_rqueue = READ_ONCE(lsk->sk_ack_backlog); |
| r->idiag_wqueue = READ_ONCE(lsk->sk_max_ack_backlog); |
| } |
| } |
| |
| if (!info) |
| return; |
| |
| mptcp_diag_fill_info(msk, info); |
| } |
| |
| static const struct inet_diag_handler mptcp_diag_handler = { |
| .owner = THIS_MODULE, |
| .dump = mptcp_diag_dump, |
| .dump_one = mptcp_diag_dump_one, |
| .idiag_get_info = mptcp_diag_get_info, |
| .idiag_type = IPPROTO_MPTCP, |
| .idiag_info_size = sizeof(struct mptcp_info), |
| }; |
| |
| static int __init mptcp_diag_init(void) |
| { |
| return inet_diag_register(&mptcp_diag_handler); |
| } |
| |
| static void __exit mptcp_diag_exit(void) |
| { |
| inet_diag_unregister(&mptcp_diag_handler); |
| } |
| |
| module_init(mptcp_diag_init); |
| module_exit(mptcp_diag_exit); |
| MODULE_LICENSE("GPL"); |
| MODULE_DESCRIPTION("MPTCP socket monitoring via SOCK_DIAG"); |
| MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-262 /* AF_INET - IPPROTO_MPTCP */); |