linux/net/tipc/node.c
Erik Hugne 40ba3cdf54 tipc: message reassembly using fragment chain
When the first fragment of a long data data message is received on a link, a
reassembly buffer large enough to hold the data from this and all subsequent
fragments of the message is allocated. The payload of each new fragment is
copied into this buffer upon arrival. When the last fragment is received, the
reassembled message is delivered upwards to the port/socket layer.

Not only is this an inefficient approach, but it may also cause bursts of
reassembly failures in low memory situations. since we may fail to allocate
the necessary large buffer in the first place. Furthermore, after 100 subsequent
such failures the link will be reset, something that in reality aggravates the
situation.

To remedy this problem, this patch introduces a different approach. Instead of
allocating a big reassembly buffer, we now append the arriving fragments
to a reassembly chain on the link, and deliver the whole chain up to the
socket layer once the last fragment has been received. This is safe because
the retransmission layer of a TIPC link always delivers packets in strict
uninterrupted order, to the reassembly layer as to all other upper layers.
Hence there can never be more than one fragment chain pending reassembly at
any given time in a link, and we can trust (but still verify) that the
fragments will be chained up in the correct order.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-07 18:30:11 -05:00

443 lines
12 KiB
C

/*
* net/tipc/node.c: TIPC node management routines
*
* Copyright (c) 2000-2006, 2012 Ericsson AB
* Copyright (c) 2005-2006, 2010-2011, 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 "node.h"
#include "name_distr.h"
#define NODE_HTABLE_SIZE 512
static void node_lost_contact(struct tipc_node *n_ptr);
static void node_established_contact(struct tipc_node *n_ptr);
static DEFINE_SPINLOCK(node_create_lock);
static struct hlist_head node_htable[NODE_HTABLE_SIZE];
LIST_HEAD(tipc_node_list);
static u32 tipc_num_nodes;
static atomic_t tipc_num_links = ATOMIC_INIT(0);
/*
* A trivial power-of-two bitmask technique is used for speed, since this
* operation is done for every incoming TIPC packet. The number of hash table
* entries has been chosen so that no hash chain exceeds 8 nodes and will
* usually be much smaller (typically only a single node).
*/
static unsigned int tipc_hashfn(u32 addr)
{
return addr & (NODE_HTABLE_SIZE - 1);
}
/*
* tipc_node_find - locate specified node object, if it exists
*/
struct tipc_node *tipc_node_find(u32 addr)
{
struct tipc_node *node;
if (unlikely(!in_own_cluster_exact(addr)))
return NULL;
hlist_for_each_entry(node, &node_htable[tipc_hashfn(addr)], hash) {
if (node->addr == addr)
return node;
}
return NULL;
}
/**
* tipc_node_create - create neighboring node
*
* Currently, this routine is called by neighbor discovery code, which holds
* net_lock for reading only. We must take node_create_lock to ensure a node
* isn't created twice if two different bearers discover the node at the same
* time. (It would be preferable to switch to holding net_lock in write mode,
* but this is a non-trivial change.)
*/
struct tipc_node *tipc_node_create(u32 addr)
{
struct tipc_node *n_ptr, *temp_node;
spin_lock_bh(&node_create_lock);
n_ptr = tipc_node_find(addr);
if (n_ptr) {
spin_unlock_bh(&node_create_lock);
return n_ptr;
}
n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
if (!n_ptr) {
spin_unlock_bh(&node_create_lock);
pr_warn("Node creation failed, no memory\n");
return NULL;
}
n_ptr->addr = addr;
spin_lock_init(&n_ptr->lock);
INIT_HLIST_NODE(&n_ptr->hash);
INIT_LIST_HEAD(&n_ptr->list);
INIT_LIST_HEAD(&n_ptr->nsub);
hlist_add_head(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);
list_for_each_entry(temp_node, &tipc_node_list, list) {
if (n_ptr->addr < temp_node->addr)
break;
}
list_add_tail(&n_ptr->list, &temp_node->list);
n_ptr->block_setup = WAIT_PEER_DOWN;
n_ptr->signature = INVALID_NODE_SIG;
tipc_num_nodes++;
spin_unlock_bh(&node_create_lock);
return n_ptr;
}
void tipc_node_delete(struct tipc_node *n_ptr)
{
list_del(&n_ptr->list);
hlist_del(&n_ptr->hash);
kfree(n_ptr);
tipc_num_nodes--;
}
/**
* tipc_node_link_up - handle addition of link
*
* Link becomes active (alone or shared) or standby, depending on its priority.
*/
void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
struct tipc_link **active = &n_ptr->active_links[0];
n_ptr->working_links++;
pr_info("Established link <%s> on network plane %c\n",
l_ptr->name, l_ptr->b_ptr->net_plane);
if (!active[0]) {
active[0] = active[1] = l_ptr;
node_established_contact(n_ptr);
return;
}
if (l_ptr->priority < active[0]->priority) {
pr_info("New link <%s> becomes standby\n", l_ptr->name);
return;
}
tipc_link_send_duplicate(active[0], l_ptr);
if (l_ptr->priority == active[0]->priority) {
active[0] = l_ptr;
return;
}
pr_info("Old link <%s> becomes standby\n", active[0]->name);
if (active[1] != active[0])
pr_info("Old link <%s> becomes standby\n", active[1]->name);
active[0] = active[1] = l_ptr;
}
/**
* node_select_active_links - select active link
*/
static void node_select_active_links(struct tipc_node *n_ptr)
{
struct tipc_link **active = &n_ptr->active_links[0];
u32 i;
u32 highest_prio = 0;
active[0] = active[1] = NULL;
for (i = 0; i < MAX_BEARERS; i++) {
struct tipc_link *l_ptr = n_ptr->links[i];
if (!l_ptr || !tipc_link_is_up(l_ptr) ||
(l_ptr->priority < highest_prio))
continue;
if (l_ptr->priority > highest_prio) {
highest_prio = l_ptr->priority;
active[0] = active[1] = l_ptr;
} else {
active[1] = l_ptr;
}
}
}
/**
* tipc_node_link_down - handle loss of link
*/
void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
struct tipc_link **active;
n_ptr->working_links--;
if (!tipc_link_is_active(l_ptr)) {
pr_info("Lost standby link <%s> on network plane %c\n",
l_ptr->name, l_ptr->b_ptr->net_plane);
return;
}
pr_info("Lost link <%s> on network plane %c\n",
l_ptr->name, l_ptr->b_ptr->net_plane);
active = &n_ptr->active_links[0];
if (active[0] == l_ptr)
active[0] = active[1];
if (active[1] == l_ptr)
active[1] = active[0];
if (active[0] == l_ptr)
node_select_active_links(n_ptr);
if (tipc_node_is_up(n_ptr))
tipc_link_changeover(l_ptr);
else
node_lost_contact(n_ptr);
}
int tipc_node_active_links(struct tipc_node *n_ptr)
{
return n_ptr->active_links[0] != NULL;
}
int tipc_node_redundant_links(struct tipc_node *n_ptr)
{
return n_ptr->working_links > 1;
}
int tipc_node_is_up(struct tipc_node *n_ptr)
{
return tipc_node_active_links(n_ptr);
}
void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
n_ptr->links[l_ptr->b_ptr->identity] = l_ptr;
atomic_inc(&tipc_num_links);
n_ptr->link_cnt++;
}
void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
n_ptr->links[l_ptr->b_ptr->identity] = NULL;
atomic_dec(&tipc_num_links);
n_ptr->link_cnt--;
}
static void node_established_contact(struct tipc_node *n_ptr)
{
tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
n_ptr->bclink.oos_state = 0;
n_ptr->bclink.acked = tipc_bclink_get_last_sent();
tipc_bclink_add_node(n_ptr->addr);
}
static void node_name_purge_complete(unsigned long node_addr)
{
struct tipc_node *n_ptr;
read_lock_bh(&tipc_net_lock);
n_ptr = tipc_node_find(node_addr);
if (n_ptr) {
tipc_node_lock(n_ptr);
n_ptr->block_setup &= ~WAIT_NAMES_GONE;
tipc_node_unlock(n_ptr);
}
read_unlock_bh(&tipc_net_lock);
}
static void node_lost_contact(struct tipc_node *n_ptr)
{
char addr_string[16];
u32 i;
pr_info("Lost contact with %s\n",
tipc_addr_string_fill(addr_string, n_ptr->addr));
/* Flush broadcast link info associated with lost node */
if (n_ptr->bclink.recv_permitted) {
while (n_ptr->bclink.deferred_head) {
struct sk_buff *buf = n_ptr->bclink.deferred_head;
n_ptr->bclink.deferred_head = buf->next;
kfree_skb(buf);
}
n_ptr->bclink.deferred_size = 0;
if (n_ptr->bclink.reasm_head) {
kfree_skb(n_ptr->bclink.reasm_head);
n_ptr->bclink.reasm_head = NULL;
n_ptr->bclink.reasm_tail = NULL;
}
tipc_bclink_remove_node(n_ptr->addr);
tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
n_ptr->bclink.recv_permitted = false;
}
/* Abort link changeover */
for (i = 0; i < MAX_BEARERS; i++) {
struct tipc_link *l_ptr = n_ptr->links[i];
if (!l_ptr)
continue;
l_ptr->reset_checkpoint = l_ptr->next_in_no;
l_ptr->exp_msg_count = 0;
tipc_link_reset_fragments(l_ptr);
}
/* Notify subscribers */
tipc_nodesub_notify(n_ptr);
/* Prevent re-contact with node until cleanup is done */
n_ptr->block_setup = WAIT_PEER_DOWN | WAIT_NAMES_GONE;
tipc_k_signal((Handler)node_name_purge_complete, n_ptr->addr);
}
struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
{
u32 domain;
struct sk_buff *buf;
struct tipc_node *n_ptr;
struct tipc_node_info node_info;
u32 payload_size;
if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
if (!tipc_addr_domain_valid(domain))
return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
" (network address)");
read_lock_bh(&tipc_net_lock);
if (!tipc_num_nodes) {
read_unlock_bh(&tipc_net_lock);
return tipc_cfg_reply_none();
}
/* For now, get space for all other nodes */
payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
if (payload_size > 32768u) {
read_unlock_bh(&tipc_net_lock);
return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
" (too many nodes)");
}
buf = tipc_cfg_reply_alloc(payload_size);
if (!buf) {
read_unlock_bh(&tipc_net_lock);
return NULL;
}
/* Add TLVs for all nodes in scope */
list_for_each_entry(n_ptr, &tipc_node_list, list) {
if (!tipc_in_scope(domain, n_ptr->addr))
continue;
node_info.addr = htonl(n_ptr->addr);
node_info.up = htonl(tipc_node_is_up(n_ptr));
tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
&node_info, sizeof(node_info));
}
read_unlock_bh(&tipc_net_lock);
return buf;
}
struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
{
u32 domain;
struct sk_buff *buf;
struct tipc_node *n_ptr;
struct tipc_link_info link_info;
u32 payload_size;
if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
if (!tipc_addr_domain_valid(domain))
return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
" (network address)");
if (!tipc_own_addr)
return tipc_cfg_reply_none();
read_lock_bh(&tipc_net_lock);
/* Get space for all unicast links + broadcast link */
payload_size = TLV_SPACE(sizeof(link_info)) *
(atomic_read(&tipc_num_links) + 1);
if (payload_size > 32768u) {
read_unlock_bh(&tipc_net_lock);
return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
" (too many links)");
}
buf = tipc_cfg_reply_alloc(payload_size);
if (!buf) {
read_unlock_bh(&tipc_net_lock);
return NULL;
}
/* Add TLV for broadcast link */
link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
link_info.up = htonl(1);
strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
/* Add TLVs for any other links in scope */
list_for_each_entry(n_ptr, &tipc_node_list, list) {
u32 i;
if (!tipc_in_scope(domain, n_ptr->addr))
continue;
tipc_node_lock(n_ptr);
for (i = 0; i < MAX_BEARERS; i++) {
if (!n_ptr->links[i])
continue;
link_info.dest = htonl(n_ptr->addr);
link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
strcpy(link_info.str, n_ptr->links[i]->name);
tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
&link_info, sizeof(link_info));
}
tipc_node_unlock(n_ptr);
}
read_unlock_bh(&tipc_net_lock);
return buf;
}