// SPDX-License-Identifier: GPL-2.0-or-later
/* incoming call handling
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/errqueue.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/icmp.h>
#include <linux/gfp.h>
#include <linux/circ_buf.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include "ar-internal.h"
static void rxrpc_dummy_notify(struct sock *sk, struct rxrpc_call *call,
unsigned long user_call_ID)
{
}
/*
* Preallocate a single service call, connection and peer and, if possible,
* give them a user ID and attach the user's side of the ID to them.
*/
static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
struct rxrpc_backlog *b,
rxrpc_notify_rx_t notify_rx,
rxrpc_user_attach_call_t user_attach_call,
unsigned long user_call_ID, gfp_t gfp,
unsigned int debug_id)
{
struct rxrpc_call *call, *xcall;
struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
struct rb_node *parent, **pp;
int max, tmp;
unsigned int size = RXRPC_BACKLOG_MAX;
unsigned int head, tail, call_head, call_tail;
max = rx->sk.sk_max_ack_backlog;
tmp = rx->sk.sk_ack_backlog;
if (tmp >= max) {
_leave(" = -ENOBUFS [full %u]", max);
return -ENOBUFS;
}
max -= tmp;
/* We don't need more conns and peers than we have calls, but on the
* other hand, we shouldn't ever use more peers than conns or conns
* than calls.
*/
call_head = b->call_backlog_head;
call_tail = READ_ONCE(b->call_backlog_tail);
tmp = CIRC_CNT(call_head, call_tail, size);
if (tmp >= max) {
_leave(" = -ENOBUFS [enough %u]", tmp);
return -ENOBUFS;
}
max = tmp + 1;
head = b->peer_backlog_head;
tail = READ_ONCE(b->peer_backlog_tail);
if (CIRC_CNT(head, tail, size) < max) {
struct rxrpc_peer *peer;
peer = rxrpc_alloc_peer(rx->local, gfp, rxrpc_peer_new_prealloc);
if (!peer)
return -ENOMEM;
b->peer_backlog[head] = peer;
smp_store_release(&b->peer_backlog_head,
(head + 1) & (size - 1));
}
head = b->conn_backlog_head;
tail = READ_ONCE(b->conn_backlog_tail);
if (CIRC_CNT(head, tail, size) < max) {
struct rxrpc_connection *conn;
conn = rxrpc_prealloc_service_connection(rxnet, gfp);
if (!conn)
return -ENOMEM;
b->conn_backlog[head] = conn;
smp_store_release(&b->conn_backlog_head,
(head + 1) & (size - 1));
}
/* Now it gets complicated, because calls get registered with the
* socket here, with a user ID preassigned by the user.
*/
call = rxrpc_alloc_call(rx, gfp, debug_id);
if (!call)
return -ENOMEM;
call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
rxrpc_set_call_state(call, RXRPC_CALL_SERVER_PREALLOC);
__set_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events);
trace_rxrpc_call(call->debug_id, refcount_read(&call->ref),
user_call_ID, rxrpc_call_new_prealloc_service);
write_lock(&rx->call_lock);
/* Check the user ID isn't already in use */
pp = &rx->calls.rb_node;
parent = NULL;
while (*pp) {
parent = *pp;
xcall = rb_entry(parent, struct rxrpc_call, sock_node);
if (user_call_ID < xcall->user_call_ID)
pp = &(*pp)->rb_left;
else if (user_call_ID > xcall->user_call_ID)
pp = &(*pp)->rb_right;
else
goto id_in_use;
}
call->user_call_ID = user_call_ID;
call->notify_rx = notify_rx;
if (user_attach_call) {
rxrpc_get_call(call, rxrpc_call_get_kernel_service);
user_attach_call(call, user_call_ID);
}
rxrpc_get_call(call, rxrpc_call_get_userid);
rb_link_node(&call->sock_node, parent, pp);
rb_insert_color(&call->sock_node, &rx->calls);
set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
list_add(&call->sock_link, &rx->sock_calls);
write_unlock(&rx->call_lock);
rxnet = call->rxnet;
spin_lock(&rxnet->call_lock);
list_add_tail_rcu(&call->link, &rxnet->calls);
spin_unlock(&rxnet->call_lock);
b->call_backlog[call_head] = call;
smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
_leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID);
return 0;
id_in_use:
write_unlock(&rx->call_lock);
rxrpc_cleanup_call(call);
_leave(" = -EBADSLT");
return -EBADSLT;
}
/*
* Allocate the preallocation buffers for incoming service calls. These must
* be charged manually.
*/
int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
{
struct rxrpc_backlog *b = rx->backlog;
if (!b) {
b = kzalloc(sizeof(struct rxrpc_backlog), gfp);
if (!b)
return -ENOMEM;
rx->backlog = b;
}
return 0;
}
/*
* Discard the preallocation on a service.
*/
void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
{
struct rxrpc_backlog *b = rx->backlog;
struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
if (!b)
return;
rx->backlog = NULL;
/* Make sure that there aren't any incoming calls in progress before we
* clear the preallocation buffers.
*/
spin_lock(&rx->incoming_lock);
spin_unlock(&rx->incoming_lock);
head = b->peer_backlog_head;
tail = b->peer_backlog_tail;
while (CIRC_CNT(head, tail, size) > 0) {
struct rxrpc_peer *peer = b->peer_backlog[tail];
rxrpc_put_local(peer->local, rxrpc_local_put_prealloc_peer);
kfree(peer);
tail = (tail + 1) & (size - 1);
}
head = b->conn_backlog_head;
tail = b->conn_backlog_tail;
while (CIRC_CNT(head, tail, size) > 0) {
struct rxrpc_connection *conn = b->conn_backlog[tail];
write_lock(&rxnet->conn_lock);
list_del(&conn->link);
list_del(&conn->proc_link);
write_unlock(&rxnet->conn_lock);
kfree(conn);
if (atomic_dec_and_test(&rxnet->nr_conns))
wake_up_var(&rxnet->nr_conns);
tail = (tail + 1) & (size - 1);
}
head = b->call_backlog_head;
tail = b->call_backlog_tail;
while (CIRC_CNT(head, tail, size) > 0) {
struct rxrpc_call *call = b->call_backlog[tail];
rcu_assign_pointer(call->socket, rx);
if (rx->discard_new_call) {
_debug("discard %lx", call->user_call_ID);
rx->discard_new_call(call, call->user_call_ID);
if (call->notify_rx)
call->notify_rx = rxrpc_dummy_notify;
rxrpc_put_call(call, rxrpc_call_put_kernel);
}
rxrpc_call_completed(call);
rxrpc_release_call(rx, call);
rxrpc_put_call(call, rxrpc_call_put_discard_prealloc);
tail = (tail + 1) & (size - 1);
}
kfree(b);
}
/*
* Allocate a new incoming call from the prealloc pool, along with a connection
* and a peer as necessary.
*/
static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
struct rxrpc_local *local,
struct rxrpc_peer *peer,
struct rxrpc_connection *conn,
const struct rxrpc_security *sec,
struct sockaddr_rxrpc *peer_srx,
struct sk_buff *skb)
{
struct rxrpc_backlog *b = rx->backlog;
struct rxrpc_call *call;
unsigned short call_head, conn_head, peer_head;
unsigned short call_tail, conn_tail, peer_tail;
unsigned short call_count, conn_count;
/* #calls >= #conns >= #peers must hold true. */
call_head = smp_load_acquire(&b->call_backlog_head);
call_tail = b->call_backlog_tail;
call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX);
conn_head = smp_load_acquire(&b->conn_backlog_head);
conn_tail = b->conn_backlog_tail;
conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX);
ASSERTCMP(conn_count, >=, call_count);
peer_head = smp_load_acquire(&b->peer_backlog_head);
peer_tail = b->peer_backlog_tail;
ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=,
conn_count);
if (call_count == 0)
return NULL;
if (!conn) {
if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_service_conn))
peer = NULL;
if (!peer) {
peer = b->peer_backlog[peer_tail];
peer->srx = *peer_srx;
b->peer_backlog[peer_tail] = NULL;
smp_store_release(&b->peer_backlog_tail,
(peer_tail + 1) &
(RXRPC_BACKLOG_MAX - 1));
rxrpc_new_incoming_peer(local, peer);
}
/* Now allocate and set up the connection */
conn = b->conn_backlog[conn_tail];
b->conn_backlog[conn_tail] = NULL;
smp_store_release(&b->conn_backlog_tail,
(conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
conn->local = rxrpc_get_local(local, rxrpc_local_get_prealloc_conn);
conn->peer = peer;
rxrpc_see_connection(conn, rxrpc_conn_see_new_service_conn);
rxrpc_new_incoming_connection(rx, conn, sec, skb);
} else {
rxrpc_get_connection(conn, rxrpc_conn_get_service_conn);
atomic_inc(&conn->active);
}
/* And now we can allocate and set up a new call */
call = b->call_backlog[call_tail];
b->call_backlog[call_tail] = NULL;
smp_store_release(&b->call_backlog_tail,
(call_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
rxrpc_see_call(call, rxrpc_call_see_accept);
call->local = rxrpc_get_local(conn->local, rxrpc_local_get_call);
call->conn = conn;
call->security = conn->security;
call->security_ix = conn->security_ix;
call->peer = rxrpc_get_peer(conn->peer, rxrpc_peer_get_accept);
call->dest_srx = peer->srx;
call->cong_ssthresh = call->peer->cong_ssthresh;
call->tx_last_sent = ktime_get_real();
return call;
}
/*
* Set up a new incoming call. Called from the I/O thread.
*
* If this is for a kernel service, when we allocate the call, it will have
* three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
* retainer ref obtained from the backlog buffer. Prealloc calls for userspace
* services only have the ref from the backlog buffer.
*
* If we want to report an error, we mark the skb with the packet type and
* abort code and return false.
*/
bool rxrpc_new_incoming_call(struct rxrpc_local *local,
struct rxrpc_peer *peer,
struct rxrpc_connection *conn,
struct sockaddr_rxrpc *peer_srx,
struct sk_buff *skb)
{
const struct rxrpc_security *sec = NULL;
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct rxrpc_call *call = NULL;
struct rxrpc_sock *rx;
_enter("");
/* Don't set up a call for anything other than a DATA packet. */
if (sp->hdr.type != RXRPC_PACKET_TYPE_DATA)
return rxrpc_protocol_error(skb, rxrpc_eproto_no_service_call);
read_lock(&local->services_lock);
/* Weed out packets to services we're not offering. Packets that would
* begin a call are explicitly rejected and the rest are just
* discarded.
*/
rx = local->service;
if (!rx || (sp->hdr.serviceId != rx->srx.srx_service &&
sp->hdr.serviceId != rx->second_service)
) {
if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA &&
sp->hdr.seq == 1)
goto unsupported_service;
goto discard;
}
if (!conn) {
sec = rxrpc_get_incoming_security(rx, skb);
if (!sec)
goto unsupported_security;
}
spin_lock(&rx->incoming_lock);
if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED ||
rx->sk.sk_state == RXRPC_CLOSE) {
rxrpc_direct_abort(skb, rxrpc_abort_shut_down,
RX_INVALID_OPERATION, -ESHUTDOWN);
goto no_call;
}
call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, peer_srx,
skb);
if (!call) {
skb->mark = RXRPC_SKB_MARK_REJECT_BUSY;
goto no_call;
}
trace_rxrpc_receive(call, rxrpc_receive_incoming,
sp->hdr.serial, sp->hdr.seq);
/* Make the call live. */
rxrpc_incoming_call(rx, call, skb);
conn = call->conn;
if (rx->notify_new_call)
rx->notify_new_call(&rx->sk, call, call->user_call_ID);
spin_lock(&conn->state_lock);
if (conn->state == RXRPC_CONN_SERVICE_UNSECURED) {
conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
rxrpc_queue_conn(call->conn, rxrpc_conn_queue_challenge);
}
spin_unlock(&conn->state_lock);
spin_unlock(&rx->incoming_lock);
read_unlock(&local->services_lock);
if (hlist_unhashed(&call->error_link)) {
spin_lock(&call->peer->lock);
hlist_add_head(&call->error_link, &call->peer->error_targets);
spin_unlock(&call->peer->lock);
}
_leave(" = %p{%d}", call, call->debug_id);
rxrpc_input_call_event(call, skb);
rxrpc_put_call(call, rxrpc_call_put_input);
return true;
unsupported_service:
read_unlock(&local->services_lock);
return rxrpc_direct_abort(skb, rxrpc_abort_service_not_offered,
RX_INVALID_OPERATION, -EOPNOTSUPP);
unsupported_security:
read_unlock(&local->services_lock);
return rxrpc_direct_abort(skb, rxrpc_abort_service_not_offered,
RX_INVALID_OPERATION, -EKEYREJECTED);
no_call:
spin_unlock(&rx->incoming_lock);
read_unlock(&local->services_lock);
_leave(" = f [%u]", skb->mark);
return false;
discard:
read_unlock(&local->services_lock);
return true;
}
/*
* Charge up socket with preallocated calls, attaching user call IDs.
*/
int rxrpc_user_charge_accept(struct rxrpc_sock *rx, unsigned long user_call_ID)
{
struct rxrpc_backlog *b = rx->backlog;
if (rx->sk.sk_state == RXRPC_CLOSE)
return -ESHUTDOWN;
return rxrpc_service_prealloc_one(rx, b, NULL, NULL, user_call_ID,
GFP_KERNEL,
atomic_inc_return(&rxrpc_debug_id));
}
/*
* rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
* @sock: The socket on which to preallocate
* @notify_rx: Event notification function for the call
* @user_attach_call: Func to attach call to user_call_ID
* @user_call_ID: The tag to attach to the preallocated call
* @gfp: The allocation conditions.
* @debug_id: The tracing debug ID.
*
* Charge up the socket with preallocated calls, each with a user ID. A
* function should be provided to effect the attachment from the user's side.
* The user is given a ref to hold on the call.
*
* Note that the call may be come connected before this function returns.
*/
int rxrpc_kernel_charge_accept(struct socket *sock,
rxrpc_notify_rx_t notify_rx,
rxrpc_user_attach_call_t user_attach_call,
unsigned long user_call_ID, gfp_t gfp,
unsigned int debug_id)
{
struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
struct rxrpc_backlog *b = rx->backlog;
if (sock->sk->sk_state == RXRPC_CLOSE)
return -ESHUTDOWN;
return rxrpc_service_prealloc_one(rx, b, notify_rx,
user_attach_call, user_call_ID,
gfp, debug_id);
}
EXPORT_SYMBOL(rxrpc_kernel_charge_accept);
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