/*
* net/tipc/server.c: TIPC server infrastructure
*
* Copyright (c) 2012-2013, Wind River Systems
* Copyright (c) 2017-2018, Ericsson AB
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "subscr.h"
#include "topsrv.h"
#include "core.h"
#include "socket.h"
#include "addr.h"
#include "msg.h"
#include "bearer.h"
#include <net/sock.h>
#include <linux/module.h>
#include <trace/events/sock.h>
/* Number of messages to send before rescheduling */
#define MAX_SEND_MSG_COUNT 25
#define MAX_RECV_MSG_COUNT 25
#define CF_CONNECTED 1
#define TIPC_SERVER_NAME_LEN 32
/**
* struct tipc_topsrv - TIPC server structure
* @conn_idr: identifier set of connection
* @idr_lock: protect the connection identifier set
* @idr_in_use: amount of allocated identifier entry
* @net: network namspace instance
* @awork: accept work item
* @rcv_wq: receive workqueue
* @send_wq: send workqueue
* @listener: topsrv listener socket
* @name: server name
*/
struct tipc_topsrv {
struct idr conn_idr;
spinlock_t idr_lock; /* for idr list */
int idr_in_use;
struct net *net;
struct work_struct awork;
struct workqueue_struct *rcv_wq;
struct workqueue_struct *send_wq;
struct socket *listener;
char name[TIPC_SERVER_NAME_LEN];
};
/**
* struct tipc_conn - TIPC connection structure
* @kref: reference counter to connection object
* @conid: connection identifier
* @sock: socket handler associated with connection
* @flags: indicates connection state
* @server: pointer to connected server
* @sub_list: lsit to all pertaing subscriptions
* @sub_lock: lock protecting the subscription list
* @rwork: receive work item
* @outqueue: pointer to first outbound message in queue
* @outqueue_lock: control access to the outqueue
* @swork: send work item
*/
struct tipc_conn {
struct kref kref;
int conid;
struct socket *sock;
unsigned long flags;
struct tipc_topsrv *server;
struct list_head sub_list;
spinlock_t sub_lock; /* for subscription list */
struct work_struct rwork;
struct list_head outqueue;
spinlock_t outqueue_lock; /* for outqueue */
struct work_struct swork;
};
/* An entry waiting to be sent */
struct outqueue_entry {
bool inactive;
struct tipc_event evt;
struct list_head list;
};
static void tipc_conn_recv_work(struct work_struct *work);
static void tipc_conn_send_work(struct work_struct *work);
static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
static bool connected(struct tipc_conn *con)
{
return con && test_bit(CF_CONNECTED, &con->flags);
}
static void tipc_conn_kref_release(struct kref *kref)
{
struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
struct tipc_topsrv *s = con->server;
struct outqueue_entry *e, *safe;
spin_lock_bh(&s->idr_lock);
idr_remove(&s->conn_idr, con->conid);
s->idr_in_use--;
spin_unlock_bh(&s->idr_lock);
if (con->sock)
sock_release(con->sock);
spin_lock_bh(&con->outqueue_lock);
list_for_each_entry_safe(e, safe, &con->outqueue, list) {
list_del(&e->list);
kfree(e);
}
spin_unlock_bh(&con->outqueue_lock);
kfree(con);
}
static void conn_put(struct tipc_conn *con)
{
kref_put(&con->kref, tipc_conn_kref_release);
}
static void conn_get(struct tipc_conn *con)
{
kref_get(&con->kref);
}
static void tipc_conn_close(struct tipc_conn *con)
{
struct sock *sk = con->sock->sk;
bool disconnect = false;
write_lock_bh(&sk->sk_callback_lock);
disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
if (disconnect) {
sk->sk_user_data = NULL;
tipc_conn_delete_sub(con, NULL);
}
write_unlock_bh(&sk->sk_callback_lock);
/* Handle concurrent calls from sending and receiving threads */
if (!disconnect)
return;
/* Don't flush pending works, -just let them expire */
kernel_sock_shutdown(con->sock, SHUT_RDWR);
conn_put(con);
}
static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s, struct socket *sock)
{
struct tipc_conn *con;
int ret;
con = kzalloc(sizeof(*con), GFP_ATOMIC);
if (!con)
return ERR_PTR(-ENOMEM);
kref_init(&con->kref);
INIT_LIST_HEAD(&con->outqueue);
INIT_LIST_HEAD(&con->sub_list);
spin_lock_init(&con->outqueue_lock);
spin_lock_init(&con->sub_lock);
INIT_WORK(&con->swork, tipc_conn_send_work);
INIT_WORK(&con->rwork, tipc_conn_recv_work);
spin_lock_bh(&s->idr_lock);
ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
if (ret < 0) {
kfree(con);
spin_unlock_bh(&s->idr_lock);
return ERR_PTR(-ENOMEM);
}
con->conid = ret;
s->idr_in_use++;
set_bit(CF_CONNECTED, &con->flags);
con->server = s;
con->sock = sock;
conn_get(con);
spin_unlock_bh(&s->idr_lock);
return con;
}
static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
{
struct tipc_conn *con;
spin_lock_bh(&s->idr_lock);
con = idr_find(&s->conn_idr, conid);
if (!connected(con) || !kref_get_unless_zero(&con->kref))
con = NULL;
spin_unlock_bh(&s->idr_lock);
return con;
}
/* tipc_conn_delete_sub - delete a specific or all subscriptions
* for a given subscriber
*/
static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
{
struct tipc_net *tn = tipc_net(con->server->net);
struct list_head *sub_list = &con->sub_list;
struct tipc_subscription *sub, *tmp;
spin_lock_bh(&con->sub_lock);
list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
tipc_sub_unsubscribe(sub);
atomic_dec(&tn->subscription_count);
if (s)
break;
}
}
spin_unlock_bh(&con->sub_lock);
}
static void tipc_conn_send_to_sock(struct tipc_conn *con)
{
struct list_head *queue = &con->outqueue;
struct tipc_topsrv *srv = con->server;
struct outqueue_entry *e;
struct tipc_event *evt;
struct msghdr msg;
struct kvec iov;
int count = 0;
int ret;
spin_lock_bh(&con->outqueue_lock);
while (!list_empty(queue)) {
e = list_first_entry(queue, struct outqueue_entry, list);
evt = &e->evt;
spin_unlock_bh(&con->outqueue_lock);
if (e->inactive)
tipc_conn_delete_sub(con, &evt->s);
memset(&msg, 0, sizeof(msg));
msg.msg_flags = MSG_DONTWAIT;
iov.iov_base = evt;
iov.iov_len = sizeof(*evt);
msg.msg_name = NULL;
if (con->sock) {
ret = kernel_sendmsg(con->sock, &msg, &iov,
1, sizeof(*evt));
if (ret == -EWOULDBLOCK || ret == 0) {
cond_resched();
return;
} else if (ret < 0) {
return tipc_conn_close(con);
}
} else {
tipc_topsrv_kern_evt(srv->net, evt);
}
/* Don't starve users filling buffers */
if (++count >= MAX_SEND_MSG_COUNT) {
cond_resched();
count = 0;
}
spin_lock_bh(&con->outqueue_lock);
list_del(&e->list);
kfree(e);
}
spin_unlock_bh(&con->outqueue_lock);
}
static void tipc_conn_send_work(struct work_struct *work)
{
struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
if (connected(con))
tipc_conn_send_to_sock(con);
conn_put(con);
}
/* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
* The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
*/
void tipc_topsrv_queue_evt(struct net *net, int conid,
u32 event, struct tipc_event *evt)
{
struct tipc_topsrv *srv = tipc_topsrv(net);
struct outqueue_entry *e;
struct tipc_conn *con;
con = tipc_conn_lookup(srv, conid);
if (!con)
return;
if (!connected(con))
goto err;
e = kmalloc(sizeof(*e), GFP_ATOMIC);
if (!e)
goto err;
e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
memcpy(&e->evt, evt, sizeof(*evt));
spin_lock_bh(&con->outqueue_lock);
list_add_tail(&e->list, &con->outqueue);
spin_unlock_bh(&con->outqueue_lock);
if (queue_work(srv->send_wq, &con->swork))
return;
err:
conn_put(con);
}
/* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
* Indicates that there now is more space in the send buffer
* The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
*/
static void tipc_conn_write_space(struct sock *sk)
{
struct tipc_conn *con;
read_lock_bh(&sk->sk_callback_lock);
con = sk->sk_user_data;
if (connected(con)) {
conn_get(con);
if (!queue_work(con->server->send_wq, &con->swork))
conn_put(con);
}
read_unlock_bh(&sk->sk_callback_lock);
}
static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
struct tipc_conn *con,
struct tipc_subscr *s)
{
struct tipc_net *tn = tipc_net(srv->net);
struct tipc_subscription *sub;
u32 s_filter = tipc_sub_read(s, filter);
if (s_filter & TIPC_SUB_CANCEL) {
tipc_sub_write(s, filter, s_filter & ~TIPC_SUB_CANCEL);
tipc_conn_delete_sub(con, s);
return 0;
}
if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
return -1;
}
sub = tipc_sub_subscribe(srv->net, s, con->conid);
if (!sub)
return -1;
atomic_inc(&tn->subscription_count);
spin_lock_bh(&con->sub_lock);
list_add(&sub->sub_list, &con->sub_list);
spin_unlock_bh(&con->sub_lock);
return 0;
}
static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
{
struct tipc_topsrv *srv = con->server;
struct sock *sk = con->sock->sk;
struct msghdr msg = {};
struct tipc_subscr s;
struct kvec iov;
int ret;
iov.iov_base = &s;
iov.iov_len = sizeof(s);
msg.msg_name = NULL;
iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, iov.iov_len);
ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
if (ret == -EWOULDBLOCK)
return -EWOULDBLOCK;
if (ret == sizeof(s)) {
read_lock_bh(&sk->sk_callback_lock);
/* RACE: the connection can be closed in the meantime */
if (likely(connected(con)))
ret = tipc_conn_rcv_sub(srv, con, &s);
read_unlock_bh(&sk->sk_callback_lock);
if (!ret)
return 0;
}
tipc_conn_close(con);
return ret;
}
static void tipc_conn_recv_work(struct work_struct *work)
{
struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
int count = 0;
while (connected(con)) {
if (tipc_conn_rcv_from_sock(con))
break;
/* Don't flood Rx machine */
if (++count >= MAX_RECV_MSG_COUNT) {
cond_resched();
count = 0;
}
}
conn_put(con);
}
/* tipc_conn_data_ready - interrupt callback indicating the socket has data
* The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
*/
static void tipc_conn_data_ready(struct sock *sk)
{
struct tipc_conn *con;
trace_sk_data_ready(sk);
read_lock_bh(&sk->sk_callback_lock);
con = sk->sk_user_data;
if (connected(con)) {
conn_get(con);
if (!queue_work(con->server->rcv_wq, &con->rwork))
conn_put(con);
}
read_unlock_bh(&sk->sk_callback_lock);
}
static void tipc_topsrv_accept(struct work_struct *work)
{
struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
struct socket *newsock, *lsock;
struct tipc_conn *con;
struct sock *newsk;
int ret;
spin_lock_bh(&srv->idr_lock);
if (!srv->listener) {
spin_unlock_bh(&srv->idr_lock);
return;
}
lsock = srv->listener;
spin_unlock_bh(&srv->idr_lock);
while (1) {
ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
if (ret < 0)
return;
con = tipc_conn_alloc(srv, newsock);
if (IS_ERR(con)) {
ret = PTR_ERR(con);
sock_release(newsock);
return;
}
/* Register callbacks */
newsk = newsock->sk;
write_lock_bh(&newsk->sk_callback_lock);
newsk->sk_data_ready = tipc_conn_data_ready;
newsk->sk_write_space = tipc_conn_write_space;
newsk->sk_user_data = con;
write_unlock_bh(&newsk->sk_callback_lock);
/* Wake up receive process in case of 'SYN+' message */
newsk->sk_data_ready(newsk);
conn_put(con);
}
}
/* tipc_topsrv_listener_data_ready - interrupt callback with connection request
* The queued job is launched into tipc_topsrv_accept()
*/
static void tipc_topsrv_listener_data_ready(struct sock *sk)
{
struct tipc_topsrv *srv;
trace_sk_data_ready(sk);
read_lock_bh(&sk->sk_callback_lock);
srv = sk->sk_user_data;
if (srv)
queue_work(srv->rcv_wq, &srv->awork);
read_unlock_bh(&sk->sk_callback_lock);
}
static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
{
struct socket *lsock = NULL;
struct sockaddr_tipc saddr;
struct sock *sk;
int rc;
rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
if (rc < 0)
return rc;
srv->listener = lsock;
sk = lsock->sk;
write_lock_bh(&sk->sk_callback_lock);
sk->sk_data_ready = tipc_topsrv_listener_data_ready;
sk->sk_user_data = srv;
write_unlock_bh(&sk->sk_callback_lock);
lock_sock(sk);
rc = tsk_set_importance(sk, TIPC_CRITICAL_IMPORTANCE);
release_sock(sk);
if (rc < 0)
goto err;
saddr.family = AF_TIPC;
saddr.addrtype = TIPC_SERVICE_RANGE;
saddr.addr.nameseq.type = TIPC_TOP_SRV;
saddr.addr.nameseq.lower = TIPC_TOP_SRV;
saddr.addr.nameseq.upper = TIPC_TOP_SRV;
saddr.scope = TIPC_NODE_SCOPE;
rc = tipc_sk_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
if (rc < 0)
goto err;
rc = kernel_listen(lsock, 0);
if (rc < 0)
goto err;
/* As server's listening socket owner and creator is the same module,
* we have to decrease TIPC module reference count to guarantee that
* it remains zero after the server socket is created, otherwise,
* executing "rmmod" command is unable to make TIPC module deleted
* after TIPC module is inserted successfully.
*
* However, the reference count is ever increased twice in
* sock_create_kern(): one is to increase the reference count of owner
* of TIPC socket's proto_ops struct; another is to increment the
* reference count of owner of TIPC proto struct. Therefore, we must
* decrement the module reference count twice to ensure that it keeps
* zero after server's listening socket is created. Of course, we
* must bump the module reference count twice as well before the socket
* is closed.
*/
module_put(lsock->ops->owner);
module_put(sk->sk_prot_creator->owner);
return 0;
err:
sock_release(lsock);
return -EINVAL;
}
bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
u32 upper, u32 filter, int *conid)
{
struct tipc_subscr sub;
struct tipc_conn *con;
int rc;
sub.seq.type = type;
sub.seq.lower = lower;
sub.seq.upper = upper;
sub.timeout = TIPC_WAIT_FOREVER;
sub.filter = filter;
*(u64 *)&sub.usr_handle = (u64)port;
con = tipc_conn_alloc(tipc_topsrv(net), NULL);
if (IS_ERR(con))
return false;
*conid = con->conid;
rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
if (rc)
conn_put(con);
conn_put(con);
return !rc;
}
void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
{
struct tipc_conn *con;
con = tipc_conn_lookup(tipc_topsrv(net), conid);
if (!con)
return;
test_and_clear_bit(CF_CONNECTED, &con->flags);
tipc_conn_delete_sub(con, NULL);
conn_put(con);
conn_put(con);
}
static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
{
u32 port = *(u32 *)&evt->s.usr_handle;
u32 self = tipc_own_addr(net);
struct sk_buff_head evtq;
struct sk_buff *skb;
skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
self, self, port, port, 0);
if (!skb)
return;
msg_set_dest_droppable(buf_msg(skb), true);
memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
skb_queue_head_init(&evtq);
__skb_queue_tail(&evtq, skb);
tipc_loopback_trace(net, &evtq);
tipc_sk_rcv(net, &evtq);
}
static int tipc_topsrv_work_start(struct tipc_topsrv *s)
{
s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
if (!s->rcv_wq) {
pr_err("can't start tipc receive workqueue\n");
return -ENOMEM;
}
s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
if (!s->send_wq) {
pr_err("can't start tipc send workqueue\n");
destroy_workqueue(s->rcv_wq);
return -ENOMEM;
}
return 0;
}
static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
{
destroy_workqueue(s->rcv_wq);
destroy_workqueue(s->send_wq);
}
static int tipc_topsrv_start(struct net *net)
{
struct tipc_net *tn = tipc_net(net);
const char name[] = "topology_server";
struct tipc_topsrv *srv;
int ret;
srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
if (!srv)
return -ENOMEM;
srv->net = net;
INIT_WORK(&srv->awork, tipc_topsrv_accept);
strscpy(srv->name, name, sizeof(srv->name));
tn->topsrv = srv;
atomic_set(&tn->subscription_count, 0);
spin_lock_init(&srv->idr_lock);
idr_init(&srv->conn_idr);
srv->idr_in_use = 0;
ret = tipc_topsrv_work_start(srv);
if (ret < 0)
goto err_start;
ret = tipc_topsrv_create_listener(srv);
if (ret < 0)
goto err_create;
return 0;
err_create:
tipc_topsrv_work_stop(srv);
err_start:
kfree(srv);
return ret;
}
static void tipc_topsrv_stop(struct net *net)
{
struct tipc_topsrv *srv = tipc_topsrv(net);
struct socket *lsock = srv->listener;
struct tipc_conn *con;
int id;
spin_lock_bh(&srv->idr_lock);
for (id = 0; srv->idr_in_use; id++) {
con = idr_find(&srv->conn_idr, id);
if (con) {
spin_unlock_bh(&srv->idr_lock);
tipc_conn_close(con);
spin_lock_bh(&srv->idr_lock);
}
}
__module_get(lsock->ops->owner);
__module_get(lsock->sk->sk_prot_creator->owner);
srv->listener = NULL;
spin_unlock_bh(&srv->idr_lock);
tipc_topsrv_work_stop(srv);
sock_release(lsock);
idr_destroy(&srv->conn_idr);
kfree(srv);
}
int __net_init tipc_topsrv_init_net(struct net *net)
{
return tipc_topsrv_start(net);
}
void __net_exit tipc_topsrv_exit_net(struct net *net)
{
tipc_topsrv_stop(net);
}
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