Root/net/tipc/node.c

1/*
2 * net/tipc/node.c: TIPC node management routines
3 *
4 * Copyright (c) 2000-2006, Ericsson AB
5 * Copyright (c) 2005-2006, Wind River Systems
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the names of the copyright holders nor the names of its
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * Alternatively, this software may be distributed under the terms of the
21 * GNU General Public License ("GPL") version 2 as published by the Free
22 * Software Foundation.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36
37#include "core.h"
38#include "config.h"
39#include "node.h"
40#include "cluster.h"
41#include "net.h"
42#include "addr.h"
43#include "node_subscr.h"
44#include "link.h"
45#include "port.h"
46#include "bearer.h"
47#include "name_distr.h"
48
49void node_print(struct print_buf *buf, struct tipc_node *n_ptr, char *str);
50static void node_lost_contact(struct tipc_node *n_ptr);
51static void node_established_contact(struct tipc_node *n_ptr);
52
53struct tipc_node *tipc_nodes = NULL; /* sorted list of nodes within cluster */
54
55static DEFINE_SPINLOCK(node_create_lock);
56
57u32 tipc_own_tag = 0;
58
59/**
60 * tipc_node_create - create neighboring node
61 *
62 * Currently, this routine is called by neighbor discovery code, which holds
63 * net_lock for reading only. We must take node_create_lock to ensure a node
64 * isn't created twice if two different bearers discover the node at the same
65 * time. (It would be preferable to switch to holding net_lock in write mode,
66 * but this is a non-trivial change.)
67 */
68
69struct tipc_node *tipc_node_create(u32 addr)
70{
71    struct cluster *c_ptr;
72    struct tipc_node *n_ptr;
73    struct tipc_node **curr_node;
74
75    spin_lock_bh(&node_create_lock);
76
77    for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
78        if (addr < n_ptr->addr)
79            break;
80        if (addr == n_ptr->addr) {
81            spin_unlock_bh(&node_create_lock);
82            return n_ptr;
83        }
84    }
85
86    n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
87    if (!n_ptr) {
88        spin_unlock_bh(&node_create_lock);
89        warn("Node creation failed, no memory\n");
90        return NULL;
91    }
92
93    c_ptr = tipc_cltr_find(addr);
94    if (!c_ptr) {
95        c_ptr = tipc_cltr_create(addr);
96    }
97    if (!c_ptr) {
98        spin_unlock_bh(&node_create_lock);
99        kfree(n_ptr);
100        return NULL;
101    }
102
103    n_ptr->addr = addr;
104        spin_lock_init(&n_ptr->lock);
105    INIT_LIST_HEAD(&n_ptr->nsub);
106    n_ptr->owner = c_ptr;
107    tipc_cltr_attach_node(c_ptr, n_ptr);
108    n_ptr->last_router = -1;
109
110    /* Insert node into ordered list */
111    for (curr_node = &tipc_nodes; *curr_node;
112         curr_node = &(*curr_node)->next) {
113        if (addr < (*curr_node)->addr) {
114            n_ptr->next = *curr_node;
115            break;
116        }
117    }
118    (*curr_node) = n_ptr;
119    spin_unlock_bh(&node_create_lock);
120    return n_ptr;
121}
122
123void tipc_node_delete(struct tipc_node *n_ptr)
124{
125    if (!n_ptr)
126        return;
127
128#if 0
129    /* Not needed because links are already deleted via tipc_bearer_stop() */
130
131    u32 l_num;
132
133    for (l_num = 0; l_num < MAX_BEARERS; l_num++) {
134        link_delete(n_ptr->links[l_num]);
135    }
136#endif
137
138    dbg("node %x deleted\n", n_ptr->addr);
139    kfree(n_ptr);
140}
141
142
143/**
144 * tipc_node_link_up - handle addition of link
145 *
146 * Link becomes active (alone or shared) or standby, depending on its priority.
147 */
148
149void tipc_node_link_up(struct tipc_node *n_ptr, struct link *l_ptr)
150{
151    struct link **active = &n_ptr->active_links[0];
152
153    n_ptr->working_links++;
154
155    info("Established link <%s> on network plane %c\n",
156         l_ptr->name, l_ptr->b_ptr->net_plane);
157
158    if (!active[0]) {
159        dbg(" link %x into %x/%x\n", l_ptr, &active[0], &active[1]);
160        active[0] = active[1] = l_ptr;
161        node_established_contact(n_ptr);
162        return;
163    }
164    if (l_ptr->priority < active[0]->priority) {
165        info("New link <%s> becomes standby\n", l_ptr->name);
166        return;
167    }
168    tipc_link_send_duplicate(active[0], l_ptr);
169    if (l_ptr->priority == active[0]->priority) {
170        active[0] = l_ptr;
171        return;
172    }
173    info("Old link <%s> becomes standby\n", active[0]->name);
174    if (active[1] != active[0])
175        info("Old link <%s> becomes standby\n", active[1]->name);
176    active[0] = active[1] = l_ptr;
177}
178
179/**
180 * node_select_active_links - select active link
181 */
182
183static void node_select_active_links(struct tipc_node *n_ptr)
184{
185    struct link **active = &n_ptr->active_links[0];
186    u32 i;
187    u32 highest_prio = 0;
188
189    active[0] = active[1] = NULL;
190
191    for (i = 0; i < MAX_BEARERS; i++) {
192        struct link *l_ptr = n_ptr->links[i];
193
194        if (!l_ptr || !tipc_link_is_up(l_ptr) ||
195            (l_ptr->priority < highest_prio))
196            continue;
197
198        if (l_ptr->priority > highest_prio) {
199            highest_prio = l_ptr->priority;
200            active[0] = active[1] = l_ptr;
201        } else {
202            active[1] = l_ptr;
203        }
204    }
205}
206
207/**
208 * tipc_node_link_down - handle loss of link
209 */
210
211void tipc_node_link_down(struct tipc_node *n_ptr, struct link *l_ptr)
212{
213    struct link **active;
214
215    n_ptr->working_links--;
216
217    if (!tipc_link_is_active(l_ptr)) {
218        info("Lost standby link <%s> on network plane %c\n",
219             l_ptr->name, l_ptr->b_ptr->net_plane);
220        return;
221    }
222    info("Lost link <%s> on network plane %c\n",
223        l_ptr->name, l_ptr->b_ptr->net_plane);
224
225    active = &n_ptr->active_links[0];
226    if (active[0] == l_ptr)
227        active[0] = active[1];
228    if (active[1] == l_ptr)
229        active[1] = active[0];
230    if (active[0] == l_ptr)
231        node_select_active_links(n_ptr);
232    if (tipc_node_is_up(n_ptr))
233        tipc_link_changeover(l_ptr);
234    else
235        node_lost_contact(n_ptr);
236}
237
238int tipc_node_has_active_links(struct tipc_node *n_ptr)
239{
240    return (n_ptr &&
241        ((n_ptr->active_links[0]) || (n_ptr->active_links[1])));
242}
243
244int tipc_node_has_redundant_links(struct tipc_node *n_ptr)
245{
246    return (n_ptr->working_links > 1);
247}
248
249static int tipc_node_has_active_routes(struct tipc_node *n_ptr)
250{
251    return (n_ptr && (n_ptr->last_router >= 0));
252}
253
254int tipc_node_is_up(struct tipc_node *n_ptr)
255{
256    return (tipc_node_has_active_links(n_ptr) || tipc_node_has_active_routes(n_ptr));
257}
258
259struct tipc_node *tipc_node_attach_link(struct link *l_ptr)
260{
261    struct tipc_node *n_ptr = tipc_node_find(l_ptr->addr);
262
263    if (!n_ptr)
264        n_ptr = tipc_node_create(l_ptr->addr);
265    if (n_ptr) {
266        u32 bearer_id = l_ptr->b_ptr->identity;
267        char addr_string[16];
268
269        if (n_ptr->link_cnt >= 2) {
270            err("Attempt to create third link to %s\n",
271                addr_string_fill(addr_string, n_ptr->addr));
272            return NULL;
273        }
274
275        if (!n_ptr->links[bearer_id]) {
276            n_ptr->links[bearer_id] = l_ptr;
277            tipc_net.zones[tipc_zone(l_ptr->addr)]->links++;
278            n_ptr->link_cnt++;
279            return n_ptr;
280        }
281        err("Attempt to establish second link on <%s> to %s \n",
282            l_ptr->b_ptr->publ.name,
283            addr_string_fill(addr_string, l_ptr->addr));
284    }
285    return NULL;
286}
287
288void tipc_node_detach_link(struct tipc_node *n_ptr, struct link *l_ptr)
289{
290    n_ptr->links[l_ptr->b_ptr->identity] = NULL;
291    tipc_net.zones[tipc_zone(l_ptr->addr)]->links--;
292    n_ptr->link_cnt--;
293}
294
295/*
296 * Routing table management - five cases to handle:
297 *
298 * 1: A link towards a zone/cluster external node comes up.
299 * => Send a multicast message updating routing tables of all
300 * system nodes within own cluster that the new destination
301 * can be reached via this node.
302 * (node.establishedContact()=>cluster.multicastNewRoute())
303 *
304 * 2: A link towards a slave node comes up.
305 * => Send a multicast message updating routing tables of all
306 * system nodes within own cluster that the new destination
307 * can be reached via this node.
308 * (node.establishedContact()=>cluster.multicastNewRoute())
309 * => Send a message to the slave node about existence
310 * of all system nodes within cluster:
311 * (node.establishedContact()=>cluster.sendLocalRoutes())
312 *
313 * 3: A new cluster local system node becomes available.
314 * => Send message(s) to this particular node containing
315 * information about all cluster external and slave
316 * nodes which can be reached via this node.
317 * (node.establishedContact()==>network.sendExternalRoutes())
318 * (node.establishedContact()==>network.sendSlaveRoutes())
319 * => Send messages to all directly connected slave nodes
320 * containing information about the existence of the new node
321 * (node.establishedContact()=>cluster.multicastNewRoute())
322 *
323 * 4: The link towards a zone/cluster external node or slave
324 * node goes down.
325 * => Send a multcast message updating routing tables of all
326 * nodes within cluster that the new destination can not any
327 * longer be reached via this node.
328 * (node.lostAllLinks()=>cluster.bcastLostRoute())
329 *
330 * 5: A cluster local system node becomes unavailable.
331 * => Remove all references to this node from the local
332 * routing tables. Note: This is a completely node
333 * local operation.
334 * (node.lostAllLinks()=>network.removeAsRouter())
335 * => Send messages to all directly connected slave nodes
336 * containing information about loss of the node
337 * (node.establishedContact()=>cluster.multicastLostRoute())
338 *
339 */
340
341static void node_established_contact(struct tipc_node *n_ptr)
342{
343    struct cluster *c_ptr;
344
345    dbg("node_established_contact:-> %x\n", n_ptr->addr);
346    if (!tipc_node_has_active_routes(n_ptr) && in_own_cluster(n_ptr->addr)) {
347        tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
348    }
349
350    /* Syncronize broadcast acks */
351    n_ptr->bclink.acked = tipc_bclink_get_last_sent();
352
353    if (is_slave(tipc_own_addr))
354        return;
355    if (!in_own_cluster(n_ptr->addr)) {
356        /* Usage case 1 (see above) */
357        c_ptr = tipc_cltr_find(tipc_own_addr);
358        if (!c_ptr)
359            c_ptr = tipc_cltr_create(tipc_own_addr);
360        if (c_ptr)
361            tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1,
362                          tipc_max_nodes);
363        return;
364    }
365
366    c_ptr = n_ptr->owner;
367    if (is_slave(n_ptr->addr)) {
368        /* Usage case 2 (see above) */
369        tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1, tipc_max_nodes);
370        tipc_cltr_send_local_routes(c_ptr, n_ptr->addr);
371        return;
372    }
373
374    if (n_ptr->bclink.supported) {
375        tipc_nmap_add(&tipc_cltr_bcast_nodes, n_ptr->addr);
376        if (n_ptr->addr < tipc_own_addr)
377            tipc_own_tag++;
378    }
379
380    /* Case 3 (see above) */
381    tipc_net_send_external_routes(n_ptr->addr);
382    tipc_cltr_send_slave_routes(c_ptr, n_ptr->addr);
383    tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, LOWEST_SLAVE,
384                  tipc_highest_allowed_slave);
385}
386
387static void node_lost_contact(struct tipc_node *n_ptr)
388{
389    struct cluster *c_ptr;
390    struct tipc_node_subscr *ns, *tns;
391    char addr_string[16];
392    u32 i;
393
394    /* Clean up broadcast reception remains */
395    n_ptr->bclink.gap_after = n_ptr->bclink.gap_to = 0;
396    while (n_ptr->bclink.deferred_head) {
397        struct sk_buff* buf = n_ptr->bclink.deferred_head;
398        n_ptr->bclink.deferred_head = buf->next;
399        buf_discard(buf);
400    }
401    if (n_ptr->bclink.defragm) {
402        buf_discard(n_ptr->bclink.defragm);
403        n_ptr->bclink.defragm = NULL;
404    }
405    if (in_own_cluster(n_ptr->addr) && n_ptr->bclink.supported) {
406        tipc_bclink_acknowledge(n_ptr, mod(n_ptr->bclink.acked + 10000));
407    }
408
409    /* Update routing tables */
410    if (is_slave(tipc_own_addr)) {
411        tipc_net_remove_as_router(n_ptr->addr);
412    } else {
413        if (!in_own_cluster(n_ptr->addr)) {
414            /* Case 4 (see above) */
415            c_ptr = tipc_cltr_find(tipc_own_addr);
416            tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
417                           tipc_max_nodes);
418        } else {
419            /* Case 5 (see above) */
420            c_ptr = tipc_cltr_find(n_ptr->addr);
421            if (is_slave(n_ptr->addr)) {
422                tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
423                               tipc_max_nodes);
424            } else {
425                if (n_ptr->bclink.supported) {
426                    tipc_nmap_remove(&tipc_cltr_bcast_nodes,
427                             n_ptr->addr);
428                    if (n_ptr->addr < tipc_own_addr)
429                        tipc_own_tag--;
430                }
431                tipc_net_remove_as_router(n_ptr->addr);
432                tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr,
433                               LOWEST_SLAVE,
434                               tipc_highest_allowed_slave);
435            }
436        }
437    }
438    if (tipc_node_has_active_routes(n_ptr))
439        return;
440
441    info("Lost contact with %s\n",
442         addr_string_fill(addr_string, n_ptr->addr));
443
444    /* Abort link changeover */
445    for (i = 0; i < MAX_BEARERS; i++) {
446        struct link *l_ptr = n_ptr->links[i];
447        if (!l_ptr)
448            continue;
449        l_ptr->reset_checkpoint = l_ptr->next_in_no;
450        l_ptr->exp_msg_count = 0;
451        tipc_link_reset_fragments(l_ptr);
452    }
453
454    /* Notify subscribers */
455    list_for_each_entry_safe(ns, tns, &n_ptr->nsub, nodesub_list) {
456        ns->node = NULL;
457        list_del_init(&ns->nodesub_list);
458        tipc_k_signal((Handler)ns->handle_node_down,
459                  (unsigned long)ns->usr_handle);
460    }
461}
462
463/**
464 * tipc_node_select_next_hop - find the next-hop node for a message
465 *
466 * Called by when cluster local lookup has failed.
467 */
468
469struct tipc_node *tipc_node_select_next_hop(u32 addr, u32 selector)
470{
471    struct tipc_node *n_ptr;
472    u32 router_addr;
473
474    if (!tipc_addr_domain_valid(addr))
475        return NULL;
476
477    /* Look for direct link to destination processsor */
478    n_ptr = tipc_node_find(addr);
479    if (n_ptr && tipc_node_has_active_links(n_ptr))
480        return n_ptr;
481
482    /* Cluster local system nodes *must* have direct links */
483    if (!is_slave(addr) && in_own_cluster(addr))
484        return NULL;
485
486    /* Look for cluster local router with direct link to node */
487    router_addr = tipc_node_select_router(n_ptr, selector);
488    if (router_addr)
489        return tipc_node_select(router_addr, selector);
490
491    /* Slave nodes can only be accessed within own cluster via a
492       known router with direct link -- if no router was found,give up */
493    if (is_slave(addr))
494        return NULL;
495
496    /* Inter zone/cluster -- find any direct link to remote cluster */
497    addr = tipc_addr(tipc_zone(addr), tipc_cluster(addr), 0);
498    n_ptr = tipc_net_select_remote_node(addr, selector);
499    if (n_ptr && tipc_node_has_active_links(n_ptr))
500        return n_ptr;
501
502    /* Last resort -- look for any router to anywhere in remote zone */
503    router_addr = tipc_net_select_router(addr, selector);
504    if (router_addr)
505        return tipc_node_select(router_addr, selector);
506
507    return NULL;
508}
509
510/**
511 * tipc_node_select_router - select router to reach specified node
512 *
513 * Uses a deterministic and fair algorithm for selecting router node.
514 */
515
516u32 tipc_node_select_router(struct tipc_node *n_ptr, u32 ref)
517{
518    u32 ulim;
519    u32 mask;
520    u32 start;
521    u32 r;
522
523    if (!n_ptr)
524        return 0;
525
526    if (n_ptr->last_router < 0)
527        return 0;
528    ulim = ((n_ptr->last_router + 1) * 32) - 1;
529
530    /* Start entry must be random */
531    mask = tipc_max_nodes;
532    while (mask > ulim)
533        mask >>= 1;
534    start = ref & mask;
535    r = start;
536
537    /* Lookup upwards with wrap-around */
538    do {
539        if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
540            break;
541    } while (++r <= ulim);
542    if (r > ulim) {
543        r = 1;
544        do {
545            if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
546                break;
547        } while (++r < start);
548        assert(r != start);
549    }
550    assert(r && (r <= ulim));
551    return tipc_addr(own_zone(), own_cluster(), r);
552}
553
554void tipc_node_add_router(struct tipc_node *n_ptr, u32 router)
555{
556    u32 r_num = tipc_node(router);
557
558    n_ptr->routers[r_num / 32] =
559        ((1 << (r_num % 32)) | n_ptr->routers[r_num / 32]);
560    n_ptr->last_router = tipc_max_nodes / 32;
561    while ((--n_ptr->last_router >= 0) &&
562           !n_ptr->routers[n_ptr->last_router]);
563}
564
565void tipc_node_remove_router(struct tipc_node *n_ptr, u32 router)
566{
567    u32 r_num = tipc_node(router);
568
569    if (n_ptr->last_router < 0)
570        return; /* No routes */
571
572    n_ptr->routers[r_num / 32] =
573        ((~(1 << (r_num % 32))) & (n_ptr->routers[r_num / 32]));
574    n_ptr->last_router = tipc_max_nodes / 32;
575    while ((--n_ptr->last_router >= 0) &&
576           !n_ptr->routers[n_ptr->last_router]);
577
578    if (!tipc_node_is_up(n_ptr))
579        node_lost_contact(n_ptr);
580}
581
582#if 0
583void node_print(struct print_buf *buf, struct tipc_node *n_ptr, char *str)
584{
585    u32 i;
586
587    tipc_printf(buf, "\n\n%s", str);
588    for (i = 0; i < MAX_BEARERS; i++) {
589        if (!n_ptr->links[i])
590            continue;
591        tipc_printf(buf, "Links[%u]: %x, ", i, n_ptr->links[i]);
592    }
593    tipc_printf(buf, "Active links: [%x,%x]\n",
594            n_ptr->active_links[0], n_ptr->active_links[1]);
595}
596#endif
597
598u32 tipc_available_nodes(const u32 domain)
599{
600    struct tipc_node *n_ptr;
601    u32 cnt = 0;
602
603    read_lock_bh(&tipc_net_lock);
604    for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
605        if (!in_scope(domain, n_ptr->addr))
606            continue;
607        if (tipc_node_is_up(n_ptr))
608            cnt++;
609    }
610    read_unlock_bh(&tipc_net_lock);
611    return cnt;
612}
613
614struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
615{
616    u32 domain;
617    struct sk_buff *buf;
618    struct tipc_node *n_ptr;
619    struct tipc_node_info node_info;
620    u32 payload_size;
621
622    if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
623        return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
624
625    domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
626    if (!tipc_addr_domain_valid(domain))
627        return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
628                           " (network address)");
629
630    read_lock_bh(&tipc_net_lock);
631    if (!tipc_nodes) {
632        read_unlock_bh(&tipc_net_lock);
633        return tipc_cfg_reply_none();
634    }
635
636    /* For now, get space for all other nodes
637       (will need to modify this when slave nodes are supported */
638
639    payload_size = TLV_SPACE(sizeof(node_info)) * (tipc_max_nodes - 1);
640    if (payload_size > 32768u) {
641        read_unlock_bh(&tipc_net_lock);
642        return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
643                           " (too many nodes)");
644    }
645    buf = tipc_cfg_reply_alloc(payload_size);
646    if (!buf) {
647        read_unlock_bh(&tipc_net_lock);
648        return NULL;
649    }
650
651    /* Add TLVs for all nodes in scope */
652
653    for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
654        if (!in_scope(domain, n_ptr->addr))
655            continue;
656        node_info.addr = htonl(n_ptr->addr);
657        node_info.up = htonl(tipc_node_is_up(n_ptr));
658        tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
659                    &node_info, sizeof(node_info));
660    }
661
662    read_unlock_bh(&tipc_net_lock);
663    return buf;
664}
665
666struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
667{
668    u32 domain;
669    struct sk_buff *buf;
670    struct tipc_node *n_ptr;
671    struct tipc_link_info link_info;
672    u32 payload_size;
673
674    if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
675        return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
676
677    domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
678    if (!tipc_addr_domain_valid(domain))
679        return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
680                           " (network address)");
681
682    if (tipc_mode != TIPC_NET_MODE)
683        return tipc_cfg_reply_none();
684
685    read_lock_bh(&tipc_net_lock);
686
687    /* Get space for all unicast links + multicast link */
688
689    payload_size = TLV_SPACE(sizeof(link_info)) *
690        (tipc_net.zones[tipc_zone(tipc_own_addr)]->links + 1);
691    if (payload_size > 32768u) {
692        read_unlock_bh(&tipc_net_lock);
693        return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
694                           " (too many links)");
695    }
696    buf = tipc_cfg_reply_alloc(payload_size);
697    if (!buf) {
698        read_unlock_bh(&tipc_net_lock);
699        return NULL;
700    }
701
702    /* Add TLV for broadcast link */
703
704    link_info.dest = htonl(tipc_own_addr & 0xfffff00);
705    link_info.up = htonl(1);
706    strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
707    tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));
708
709    /* Add TLVs for any other links in scope */
710
711    for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
712        u32 i;
713
714        if (!in_scope(domain, n_ptr->addr))
715            continue;
716        tipc_node_lock(n_ptr);
717        for (i = 0; i < MAX_BEARERS; i++) {
718            if (!n_ptr->links[i])
719                continue;
720            link_info.dest = htonl(n_ptr->addr);
721            link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
722            strcpy(link_info.str, n_ptr->links[i]->name);
723            tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
724                        &link_info, sizeof(link_info));
725        }
726        tipc_node_unlock(n_ptr);
727    }
728
729    read_unlock_bh(&tipc_net_lock);
730    return buf;
731}
732

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