tipc: use pseudo message to wake up sockets after link congestion

[mirror_ubuntu-bionic-kernel.git] / net / tipc / port.c

/*
 * net/tipc/port.c: TIPC port code
 *
 * Copyright (c) 1992-2007, 2014, Ericsson AB
 * Copyright (c) 2004-2008, 2010-2013, Wind River Systems
 * 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 "core.h"
#include "config.h"
#include "port.h"
#include "name_table.h"
#include "socket.h"

/* Connection management: */
#define PROBING_INTERVAL 3600000        /* [ms] => 1 h */

#define MAX_REJECT_SIZE 1024

DEFINE_SPINLOCK(tipc_port_list_lock);

static LIST_HEAD(ports);
static void port_handle_node_down(unsigned long ref);
static struct sk_buff *port_build_self_abort_msg(struct tipc_port *, u32 err);
static struct sk_buff *port_build_peer_abort_msg(struct tipc_port *, u32 err);
static void port_timeout(unsigned long ref);

/**
 * tipc_port_peer_msg - verify message was sent by connected port's peer
 *
 * Handles cases where the node's network address has changed from
 * the default of <0.0.0> to its configured setting.
 */
int tipc_port_peer_msg(struct tipc_port *p_ptr, struct tipc_msg *msg)
{
        u32 peernode;
        u32 orignode;

        if (msg_origport(msg) != tipc_port_peerport(p_ptr))
                return 0;

        orignode = msg_orignode(msg);
        peernode = tipc_port_peernode(p_ptr);
        return (orignode == peernode) ||
                (!orignode && (peernode == tipc_own_addr)) ||
                (!peernode && (orignode == tipc_own_addr));
}

/* tipc_port_init - intiate TIPC port and lock it
 *
 * Returns obtained reference if initialization is successful, zero otherwise
 */
u32 tipc_port_init(struct tipc_port *p_ptr,
                   const unsigned int importance)
{
        struct tipc_msg *msg;
        u32 ref;

        ref = tipc_ref_acquire(p_ptr, &p_ptr->lock);
        if (!ref) {
                pr_warn("Port registration failed, ref. table exhausted\n");
                return 0;
        }

        p_ptr->max_pkt = MAX_PKT_DEFAULT;
        p_ptr->ref = ref;
        INIT_LIST_HEAD(&p_ptr->subscription.nodesub_list);
        k_init_timer(&p_ptr->timer, (Handler)port_timeout, ref);
        INIT_LIST_HEAD(&p_ptr->publications);
        INIT_LIST_HEAD(&p_ptr->port_list);

        /*
         * Must hold port list lock while initializing message header template
         * to ensure a change to node's own network address doesn't result
         * in template containing out-dated network address information
         */
        spin_lock_bh(&tipc_port_list_lock);
        msg = &p_ptr->phdr;
        tipc_msg_init(msg, importance, TIPC_NAMED_MSG, NAMED_H_SIZE, 0);
        msg_set_origport(msg, ref);
        list_add_tail(&p_ptr->port_list, &ports);
        spin_unlock_bh(&tipc_port_list_lock);
        return ref;
}

void tipc_port_destroy(struct tipc_port *p_ptr)
{
        struct sk_buff *buf = NULL;
        struct tipc_msg *msg = NULL;
        u32 peer;

        tipc_withdraw(p_ptr, 0, NULL);

        spin_lock_bh(p_ptr->lock);
        tipc_ref_discard(p_ptr->ref);
        spin_unlock_bh(p_ptr->lock);

        k_cancel_timer(&p_ptr->timer);
        if (p_ptr->connected) {
                buf = port_build_peer_abort_msg(p_ptr, TIPC_ERR_NO_PORT);
                tipc_nodesub_unsubscribe(&p_ptr->subscription);
                msg = buf_msg(buf);
                peer = msg_destnode(msg);
                tipc_link_xmit(buf, peer, msg_link_selector(msg));
        }
        spin_lock_bh(&tipc_port_list_lock);
        list_del(&p_ptr->port_list);
        spin_unlock_bh(&tipc_port_list_lock);
        k_term_timer(&p_ptr->timer);
}

/*
 * port_build_proto_msg(): create connection protocol message for port
 *
 * On entry the port must be locked and connected.
 */
static struct sk_buff *port_build_proto_msg(struct tipc_port *p_ptr,
                                            u32 type, u32 ack)
{
        struct sk_buff *buf;
        struct tipc_msg *msg;

        buf = tipc_buf_acquire(INT_H_SIZE);
        if (buf) {
                msg = buf_msg(buf);
                tipc_msg_init(msg, CONN_MANAGER, type, INT_H_SIZE,
                              tipc_port_peernode(p_ptr));
                msg_set_destport(msg, tipc_port_peerport(p_ptr));
                msg_set_origport(msg, p_ptr->ref);
                msg_set_msgcnt(msg, ack);
                buf->next = NULL;
        }
        return buf;
}

static void port_timeout(unsigned long ref)
{
        struct tipc_port *p_ptr = tipc_port_lock(ref);
        struct sk_buff *buf = NULL;
        struct tipc_msg *msg = NULL;

        if (!p_ptr)
                return;

        if (!p_ptr->connected) {
                tipc_port_unlock(p_ptr);
                return;
        }

        /* Last probe answered ? */
        if (p_ptr->probing_state == TIPC_CONN_PROBING) {
                buf = port_build_self_abort_msg(p_ptr, TIPC_ERR_NO_PORT);
        } else {
                buf = port_build_proto_msg(p_ptr, CONN_PROBE, 0);
                p_ptr->probing_state = TIPC_CONN_PROBING;
                k_start_timer(&p_ptr->timer, p_ptr->probing_interval);
        }
        tipc_port_unlock(p_ptr);
        msg = buf_msg(buf);
        tipc_link_xmit(buf, msg_destnode(msg),  msg_link_selector(msg));
}


static void port_handle_node_down(unsigned long ref)
{
        struct tipc_port *p_ptr = tipc_port_lock(ref);
        struct sk_buff *buf = NULL;
        struct tipc_msg *msg = NULL;

        if (!p_ptr)
                return;
        buf = port_build_self_abort_msg(p_ptr, TIPC_ERR_NO_NODE);
        tipc_port_unlock(p_ptr);
        msg = buf_msg(buf);
        tipc_link_xmit(buf, msg_destnode(msg),  msg_link_selector(msg));
}


static struct sk_buff *port_build_self_abort_msg(struct tipc_port *p_ptr, u32 err)
{
        struct sk_buff *buf = port_build_peer_abort_msg(p_ptr, err);

        if (buf) {
                struct tipc_msg *msg = buf_msg(buf);
                msg_swap_words(msg, 4, 5);
                msg_swap_words(msg, 6, 7);
                buf->next = NULL;
        }
        return buf;
}


static struct sk_buff *port_build_peer_abort_msg(struct tipc_port *p_ptr, u32 err)
{
        struct sk_buff *buf;
        struct tipc_msg *msg;
        u32 imp;

        if (!p_ptr->connected)
                return NULL;

        buf = tipc_buf_acquire(BASIC_H_SIZE);
        if (buf) {
                msg = buf_msg(buf);
                memcpy(msg, &p_ptr->phdr, BASIC_H_SIZE);
                msg_set_hdr_sz(msg, BASIC_H_SIZE);
                msg_set_size(msg, BASIC_H_SIZE);
                imp = msg_importance(msg);
                if (imp < TIPC_CRITICAL_IMPORTANCE)
                        msg_set_importance(msg, ++imp);
                msg_set_errcode(msg, err);
                buf->next = NULL;
        }
        return buf;
}

static int port_print(struct tipc_port *p_ptr, char *buf, int len, int full_id)
{
        struct publication *publ;
        int ret;

        if (full_id)
                ret = tipc_snprintf(buf, len, "<%u.%u.%u:%u>:",
                                    tipc_zone(tipc_own_addr),
                                    tipc_cluster(tipc_own_addr),
                                    tipc_node(tipc_own_addr), p_ptr->ref);
        else
                ret = tipc_snprintf(buf, len, "%-10u:", p_ptr->ref);

        if (p_ptr->connected) {
                u32 dport = tipc_port_peerport(p_ptr);
                u32 destnode = tipc_port_peernode(p_ptr);

                ret += tipc_snprintf(buf + ret, len - ret,
                                     " connected to <%u.%u.%u:%u>",
                                     tipc_zone(destnode),
                                     tipc_cluster(destnode),
                                     tipc_node(destnode), dport);
                if (p_ptr->conn_type != 0)
                        ret += tipc_snprintf(buf + ret, len - ret,
                                             " via {%u,%u}", p_ptr->conn_type,
                                             p_ptr->conn_instance);
        } else if (p_ptr->published) {
                ret += tipc_snprintf(buf + ret, len - ret, " bound to");
                list_for_each_entry(publ, &p_ptr->publications, pport_list) {
                        if (publ->lower == publ->upper)
                                ret += tipc_snprintf(buf + ret, len - ret,
                                                     " {%u,%u}", publ->type,
                                                     publ->lower);
                        else
                                ret += tipc_snprintf(buf + ret, len - ret,
                                                     " {%u,%u,%u}", publ->type,
                                                     publ->lower, publ->upper);
                }
        }
        ret += tipc_snprintf(buf + ret, len - ret, "\n");
        return ret;
}

struct sk_buff *tipc_port_get_ports(void)
{
        struct sk_buff *buf;
        struct tlv_desc *rep_tlv;
        char *pb;
        int pb_len;
        struct tipc_port *p_ptr;
        int str_len = 0;

        buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
        if (!buf)
                return NULL;
        rep_tlv = (struct tlv_desc *)buf->data;
        pb = TLV_DATA(rep_tlv);
        pb_len = ULTRA_STRING_MAX_LEN;

        spin_lock_bh(&tipc_port_list_lock);
        list_for_each_entry(p_ptr, &ports, port_list) {
                spin_lock_bh(p_ptr->lock);
                str_len += port_print(p_ptr, pb, pb_len, 0);
                spin_unlock_bh(p_ptr->lock);
        }
        spin_unlock_bh(&tipc_port_list_lock);
        str_len += 1;   /* for "\0" */
        skb_put(buf, TLV_SPACE(str_len));
        TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);

        return buf;
}

void tipc_port_reinit(void)
{
        struct tipc_port *p_ptr;
        struct tipc_msg *msg;

        spin_lock_bh(&tipc_port_list_lock);
        list_for_each_entry(p_ptr, &ports, port_list) {
                msg = &p_ptr->phdr;
                msg_set_prevnode(msg, tipc_own_addr);
                msg_set_orignode(msg, tipc_own_addr);
        }
        spin_unlock_bh(&tipc_port_list_lock);
}

void tipc_acknowledge(u32 ref, u32 ack)
{
        struct tipc_port *p_ptr;
        struct sk_buff *buf = NULL;
        struct tipc_msg *msg;

        p_ptr = tipc_port_lock(ref);
        if (!p_ptr)
                return;
        if (p_ptr->connected)
                buf = port_build_proto_msg(p_ptr, CONN_ACK, ack);

        tipc_port_unlock(p_ptr);
        if (!buf)
                return;
        msg = buf_msg(buf);
        tipc_link_xmit(buf, msg_destnode(msg),  msg_link_selector(msg));
}

int tipc_publish(struct tipc_port *p_ptr, unsigned int scope,
                 struct tipc_name_seq const *seq)
{
        struct publication *publ;
        u32 key;

        if (p_ptr->connected)
                return -EINVAL;
        key = p_ptr->ref + p_ptr->pub_count + 1;
        if (key == p_ptr->ref)
                return -EADDRINUSE;

        publ = tipc_nametbl_publish(seq->type, seq->lower, seq->upper,
                                    scope, p_ptr->ref, key);
        if (publ) {
                list_add(&publ->pport_list, &p_ptr->publications);
                p_ptr->pub_count++;
                p_ptr->published = 1;
                return 0;
        }
        return -EINVAL;
}

int tipc_withdraw(struct tipc_port *p_ptr, unsigned int scope,
                  struct tipc_name_seq const *seq)
{
        struct publication *publ;
        struct publication *tpubl;
        int res = -EINVAL;

        if (!seq) {
                list_for_each_entry_safe(publ, tpubl,
                                         &p_ptr->publications, pport_list) {
                        tipc_nametbl_withdraw(publ->type, publ->lower,
                                              publ->ref, publ->key);
                }
                res = 0;
        } else {
                list_for_each_entry_safe(publ, tpubl,
                                         &p_ptr->publications, pport_list) {
                        if (publ->scope != scope)
                                continue;
                        if (publ->type != seq->type)
                                continue;
                        if (publ->lower != seq->lower)
                                continue;
                        if (publ->upper != seq->upper)
                                break;
                        tipc_nametbl_withdraw(publ->type, publ->lower,
                                              publ->ref, publ->key);
                        res = 0;
                        break;
                }
        }
        if (list_empty(&p_ptr->publications))
                p_ptr->published = 0;
        return res;
}

int tipc_port_connect(u32 ref, struct tipc_portid const *peer)
{
        struct tipc_port *p_ptr;
        int res;

        p_ptr = tipc_port_lock(ref);
        if (!p_ptr)
                return -EINVAL;
        res = __tipc_port_connect(ref, p_ptr, peer);
        tipc_port_unlock(p_ptr);
        return res;
}

/*
 * __tipc_port_connect - connect to a remote peer
 *
 * Port must be locked.
 */
int __tipc_port_connect(u32 ref, struct tipc_port *p_ptr,
                        struct tipc_portid const *peer)
{
        struct tipc_msg *msg;
        int res = -EINVAL;

        if (p_ptr->published || p_ptr->connected)
                goto exit;
        if (!peer->ref)
                goto exit;

        msg = &p_ptr->phdr;
        msg_set_destnode(msg, peer->node);
        msg_set_destport(msg, peer->ref);
        msg_set_type(msg, TIPC_CONN_MSG);
        msg_set_lookup_scope(msg, 0);
        msg_set_hdr_sz(msg, SHORT_H_SIZE);

        p_ptr->probing_interval = PROBING_INTERVAL;
        p_ptr->probing_state = TIPC_CONN_OK;
        p_ptr->connected = 1;
        k_start_timer(&p_ptr->timer, p_ptr->probing_interval);

        tipc_nodesub_subscribe(&p_ptr->subscription, peer->node,
                          (void *)(unsigned long)ref,
                          (net_ev_handler)port_handle_node_down);
        res = 0;
exit:
        p_ptr->max_pkt = tipc_node_get_mtu(peer->node, ref);
        return res;
}

/*
 * __tipc_disconnect - disconnect port from peer
 *
 * Port must be locked.
 */
int __tipc_port_disconnect(struct tipc_port *tp_ptr)
{
        if (tp_ptr->connected) {
                tp_ptr->connected = 0;
                /* let timer expire on it's own to avoid deadlock! */
                tipc_nodesub_unsubscribe(&tp_ptr->subscription);
                return 0;
        }

        return -ENOTCONN;
}

/*
 * tipc_port_disconnect(): Disconnect port form peer.
 *                    This is a node local operation.
 */
int tipc_port_disconnect(u32 ref)
{
        struct tipc_port *p_ptr;
        int res;

        p_ptr = tipc_port_lock(ref);
        if (!p_ptr)
                return -EINVAL;
        res = __tipc_port_disconnect(p_ptr);
        tipc_port_unlock(p_ptr);
        return res;
}

/*
 * tipc_port_shutdown(): Send a SHUTDOWN msg to peer and disconnect
 */
int tipc_port_shutdown(u32 ref)
{
        struct tipc_msg *msg;
        struct tipc_port *p_ptr;
        struct sk_buff *buf = NULL;

        p_ptr = tipc_port_lock(ref);
        if (!p_ptr)
                return -EINVAL;

        buf = port_build_peer_abort_msg(p_ptr, TIPC_CONN_SHUTDOWN);
        tipc_port_unlock(p_ptr);
        msg = buf_msg(buf);
        tipc_link_xmit(buf, msg_destnode(msg),  msg_link_selector(msg));
        return tipc_port_disconnect(ref);
}