[Olsr-dev] [PATCH v1 1/1] lq_packet: only report a neighbour once in a hello message

Conrad Lara (spam-protected)
Wed Jan 18 06:55:36 CET 2017


I believe this issue goes much deeper on the RX side than was first thought and don't see a way to solve this on the TX side.as shown in this patch.

Using this patch (and the previous test patch) I can confirm the following issue:

Lab setup as before (using latest head and patch on both sides)

Run the following command on Node61:
$ sudo iptables -F; sudo killall olsrd; sudo /usr/local/sbin/olsrd; sleep 60; echo "About to block"; sleep 10;  sudo iptables -I INPUT -i eth2.2580 -s 172.28.175.97 -j DROP; sleep 60; echo "OK check olsrd";

(make sure iptables is clear,  start olsrd up, sleep 60 so the link establishes , output some text for me to know to check OLSR, block OLSR packets, and then  have me check again)

I get back following on links BEFORE the IP block,

Links
Local IP	Remote IP	Hysteresis	LinkCost
172.29.175.61	172.29.175.97	0.00	(1.000/1.000) 0.100
172.29.175.61	172.28.175.97	0.00	(1.000/1.000) 0.100
172.31.175.61	172.31.175.97	0.00	(1.000/1.000) 1.000

(all is good)

And after the block:

Links
Local IP	Remote IP	Hysteresis	LinkCost
172.29.175.61	172.29.175.97	0.00	(1.000/1.000) 0.100
172.29.175.61	172.28.175.97	0.00	(1.000/1.000) 0.100
172.31.175.61	172.31.175.97	0.00	(1.000/1.000) 1.000

However this should not be possible because  packets from 172.28.175.97 are being blocked by the IPTables the link can not be symmetric it should read 0/1 and be an asymmetric link.

Just to confirm the firewall is working correctly I then execute on node61

$sudo killall olsrd; sudo /etc/init.d/olsrd;  

The links list looks as follows (confirming the ip packets are indeed initially blocked)

Links
Local IP	Remote IP	Hysteresis	LinkCost
172.31.175.61	172.31.175.97	0.00	(1.000/1.000) 1.000
172.29.175.61	172.29.175.97	0.00	(1.000/1.000) 0.100


---- Teco Boot <(spam-protected)> wrote: 
> There are glitches when hello is fragmented, right?
And there is a little bit of overhead. It may confuse.
But yes, this is a short patch!

Teco


> Op 16 jan. 2017, om 18:14 heeft Ferry Huberts <(spam-protected)> het volgende geschreven:
> 
> I think I may have stumbled onto a MUCH easier fix to this problem.
> 
> 
> The actual problem is quite involved (with fragmented hello messages etc) but it all boils down to a later UNSPEC link overwriting a previous SYM/ASYM/other link on the receiving end.
> 
> Since the neighbours in a hello message are already ordered when the hello message is sent out, the following patch also solves it.
> 
> Opinions?
> 
> 
> 
> diff --git a/src/lq_packet.c b/src/lq_packet.c
> index d44e654..287f4b4 100644
> --- a/src/lq_packet.c
> +++ b/src/lq_packet.c
> @@ -326,7 +326,7 @@ serialize_common(struct olsr_common *comm)
> static void
> serialize_lq_hello(struct lq_hello_message *lq_hello, struct interface_olsr *outif)
> {
> -  static const int LINK_ORDER[] = { SYM_LINK, UNSPEC_LINK, ASYM_LINK, LOST_LINK };
> +  static const int LINK_ORDER[] = { UNSPEC_LINK, LOST_LINK, ASYM_LINK, SYM_LINK };
>   int rem, size, req, expected_size = 0;
>   struct lq_hello_info_header *info_head;
>   struct lq_hello_neighbor *neigh;
> 
> 
> 
> 
> On 13/01/17 09:05, Ferry Huberts wrote:
>> From: "Iwan G. Flameling" <(spam-protected)>
>> 
>> A while ago we noticed that neighbours of nodes with multiple interfaces
>> on the same medium report infinite costs on their links to those nodes.
>> 
>> This problem is 100% reproducible.
>> 
>> Below is the setup in which we noticed the problem.
>> 
>>       wlan0                                                 wlan0
>>       172.31.175.97/16                           172.31.175.61/16
>>    (((*))) ------------------------------------------------- (((*)))
>>       |                                                         |
>>       |                                                         |
>>       |                                                         |
>>   ____|___   172.29.175.97/15   ________  172.29.175.61/15  ____|____
>>  |         |-eth1.2580---------|        |--------eth1.2580-|         |
>>  | Node 97 |                   | Switch |                  | Node 61 |
>>  |_________|-eth2.2580---------|________|                  |_________|
>>              172.28.175.97/15
>> 
>> In this setup node 97 will report normal link costs for its (wired) links
>> to node 61 (see the first table below), while node 61 will report infinite
>> link costs for both its (wired) links to node 97 (see the second table
>> below).
>> 
>>  Table: Links (node 97)
>>  Local IP       Remote IP       Hyst.   LQ      NLQ     Cost
>>  172.29.175.97  172.29.175.61   0.000   1.000   1.000   0.100
>>  172.28.175.97  172.29.175.61   0.000   1.000   1.000   0.100
>>  172.31.175.97  172.31.175.61   0.000   1.000   1.000   1.000
>> 
>>  Table: Links (node 61)
>>  Local IP       Remote IP       Hyst.   LQ      NLQ     Cost
>>  172.29.175.61  172.29.175.97   0.000   1.000   0.000   INFINITE
>>  172.29.175.61  172.28.175.97   0.000   1.000   0.000   INFINITE
>>  172.31.175.61  172.31.175.97   0.000   1.000   1.000   1.000
>> 
>> Checking the HELLO messages that are received on node 61 from node 97,
>> we see the following:
>> 
>>  [node 61] # tcpdump -vni eth1.2580 udp port 698
>>  tcpdump: listening on eth1.2580, link-type EN10MB (Ethernet), capture size 262144 bytes
>>  06:21:23.528204 IP (tos 0xc0, ttl 1, id 42455, offset 0, flags [DF], proto UDP (17), length 80)
>>      172.28.175.97.698 > 255.255.255.255.698: OLSRv4, seq 0xf7c0, length 52
>>     Hello-LQ Message (0xc9), originator 172.31.175.97, ttl 1, hop 0
>>       vtime 3.000s, msg-seq 0x533d, length 48
>>       hello-time 1.000s, MPR willingness 3
>>         link-type Symmetric, neighbor-type Symmetric, len 12
>>           neighbor 172.29.175.61, link-quality 0.00%, neighbor-link-quality 0.00%
>>         link-type Unspecified, neighbor-type Symmetric, len 20
>>           neighbor 172.31.175.61, link-quality 0.00%, neighbor-link-quality 0.00%
>>           neighbor 172.29.175.61, link-quality 0.00%, neighbor-link-quality 0.00%
>> 
>> Node 61 receives HELLO messages from node 97 that report (amongst others):
>> 1- a  SYMMETRIC   link-type to node 61 (172.29.175.61)
>> 2- an UNSPECIFIED link-type to node 61 (172.29.175.61)
>> 
>> Clearly, this is 'confusing' and the root cause of why node 61 reports
>> infinite costs for the links, as shown above.
>> 
>> We pose that in a HELLO message the same neighbour should NEVER be
>> reported with conflicting information.
>> 
>> Proposed solution:
>> 
>> 1- NEVER report a neighbour more than once in a HELLO message
>> 2- Use the 'best' values for a neighbour that is reported in a HELLO
>>   message
>> 
>> This requires:
>> 
>> 1- De-duplication of neighbours when constructing a HELLO message.
>> 
>> 2- When a neighbour is already present in the HELLO message
>>   that is under construction then he 'best' values must be determined
>>   and those in the neighbour that is already present should only be
>>   overwritten if those are worse.
>> 
>> This patch implements that solution.
>> 
>> Signed-off-by: Iwan G. Flameling <(spam-protected)>
>> Signed-off-by: Ferry Huberts <(spam-protected)>
>> ---
>> src/lq_packet.c               |  52 ++++++++++++----
>> src/lq_plugin.c               |   5 +-
>> src/lq_plugin.h               |   4 +-
>> src/lq_plugin_default_ff.c    |  13 +++-
>> src/lq_plugin_default_ffeth.c |  13 +++-
>> src/lq_plugin_default_float.c |  19 +++++-
>> src/lq_plugin_default_fpm.c   |  19 +++++-
>> src/olsr_protocol.h           | 136 ++++++++++++++++++++++++++++++++++++++++++
>> 8 files changed, 236 insertions(+), 25 deletions(-)
>> 
>> diff --git a/src/lq_packet.c b/src/lq_packet.c
>> index d44e654..2e8e027 100644
>> --- a/src/lq_packet.c
>> +++ b/src/lq_packet.c
>> @@ -68,6 +68,21 @@ bool lq_tc_pending = false;
>> static uint32_t msg_buffer_aligned[(MAXMESSAGESIZE - OLSR_HEADERSIZE) / sizeof(uint32_t) + 1];
>> static unsigned char *const msg_buffer = (unsigned char *)msg_buffer_aligned;
>> 
>> +static struct lq_hello_neighbor * neigh_find(struct link_entry *link, struct lq_hello_message *lq_hello) {
>> +  struct lq_hello_neighbor *neigh;
>> +
>> +  assert(link);
>> +  assert(lq_hello);
>> +
>> +  for (neigh = lq_hello->neigh; neigh; neigh = neigh->next) {
>> +    if (ipequal(&link->neighbor_iface_addr, &neigh->addr)) {
>> +      return neigh;
>> +    }
>> +  }
>> +
>> +  return NULL ;
>> +}
>> +
>> static void
>> create_lq_hello(struct lq_hello_message *lq_hello, struct interface_olsr *outif)
>> {
>> @@ -92,46 +107,57 @@ create_lq_hello(struct lq_hello_message *lq_hello, struct interface_olsr *outif)
>>   // loop through the link set
>> 
>>   OLSR_FOR_ALL_LINK_ENTRIES(walker) {
>> +    uint8_t link_type;
>> +    uint8_t neigh_type;
>> 
>>     // allocate a neighbour entry
>> -    struct lq_hello_neighbor *neigh = olsr_malloc_lq_hello_neighbor("Build LQ_HELLO");
>> +    struct lq_hello_neighbor *neigh = neigh_find(walker, lq_hello);
>> +    bool neigh_is_new = (neigh == NULL );
>> +    neigh = neigh_is_new ? olsr_malloc_lq_hello_neighbor("Build LQ_HELLO") : neigh;
>> 
>>     // a) this neighbor interface IS NOT visible via the output interface
>>     if (!ipequal(&walker->local_iface_addr, &outif->ip_addr))
>> -      neigh->link_type = UNSPEC_LINK;
>> +      link_type = UNSPEC_LINK;
>> 
>>     // b) this neighbor interface IS visible via the output interface
>> 
>>     else
>> -      neigh->link_type = lookup_link_status(walker);
>> +      link_type = lookup_link_status(walker);
>> +
>> +    if (neigh_is_new || link_type_compare(neigh->link_type, link_type))
>> +      neigh->link_type = link_type;
>> 
>>     // set the entry's link quality
>> -    olsr_copy_hello_lq(neigh, walker);
>> +    olsr_copy_hello_lq(neigh, walker, neigh_is_new);
>> 
>>     // set the entry's neighbour type
>> 
>>     if (walker->neighbor->is_mpr)
>> -      neigh->neigh_type = MPR_NEIGH;
>> +      neigh_type = MPR_NEIGH;
>> 
>>     else if (walker->neighbor->status == SYM)
>> -      neigh->neigh_type = SYM_NEIGH;
>> +      neigh_type = SYM_NEIGH;
>> 
>>     else if (walker->neighbor->status == NOT_SYM)
>> -      neigh->neigh_type = NOT_NEIGH;
>> +      neigh_type = NOT_NEIGH;
>> 
>>     else {
>>       OLSR_PRINTF(0, "Error: neigh_type undefined");
>> -      neigh->neigh_type = NOT_NEIGH;
>> +      neigh_type = NOT_NEIGH;
>>     }
>> 
>> -    // set the entry's neighbour interface address
>> +    if (neigh_is_new || neigh_type_compare(neigh->neigh_type, neigh_type))
>> +      neigh->neigh_type = neigh_type;
>> 
>> -    neigh->addr = walker->neighbor_iface_addr;
>> +    if (neigh_is_new) {
>> +      // set the entry's neighbour interface address
>> 
>> -    // queue the neighbour entry
>> -    neigh->next = lq_hello->neigh;
>> -    lq_hello->neigh = neigh;
>> +      neigh->addr = walker->neighbor_iface_addr;
>> 
>> +      // queue the neighbour entry
>> +      neigh->next = lq_hello->neigh;
>> +      lq_hello->neigh = neigh;
>> +    }
>>   }
>>   OLSR_FOR_ALL_LINK_ENTRIES_END(walker);
>> }
>> diff --git a/src/lq_plugin.c b/src/lq_plugin.c
>> index a917c84..01c6e4e 100644
>> --- a/src/lq_plugin.c
>> +++ b/src/lq_plugin.c
>> @@ -351,13 +351,14 @@ get_linkcost_scaled(olsr_linkcost cost, bool route)
>>  *
>>  * @param target pointer to target lq_hello_neighbor
>>  * @param source pointer to source link_entry
>> + * @param force true to force the copy, otherwise only copy when source is 'better' than target
>>  */
>> void
>> -olsr_copy_hello_lq(struct lq_hello_neighbor *target, struct link_entry *source)
>> +olsr_copy_hello_lq(struct lq_hello_neighbor *target, struct link_entry *source, bool force)
>> {
>>   assert((const char *)target + sizeof(*target) >= (const char *)target->linkquality);
>>   assert((const char *)source + sizeof(*source) >= (const char *)source->linkquality);
>> -  active_lq_handler->copy_link_lq_into_neigh(target->linkquality, source->linkquality);
>> +  active_lq_handler->copy_link_lq_into_neigh(target->linkquality, source->linkquality, force);
>> }
>> 
>> /**
>> diff --git a/src/lq_plugin.h b/src/lq_plugin.h
>> index 747a70c..26baba4 100644
>> --- a/src/lq_plugin.h
>> +++ b/src/lq_plugin.h
>> @@ -76,7 +76,7 @@ struct lq_handler {
>>   void (*packet_loss_handler) (struct link_entry * entry, void *lq, bool lost);
>> 
>>   void (*memorize_foreign_hello) (void *local, void *foreign);
>> -  void (*copy_link_lq_into_neigh) (void *target, void *source);
>> +  void (*copy_link_lq_into_neigh) (void *target, void *source, bool force);
>>   void (*copy_link_lq_into_tc) (void *target, void *source);
>>   void (*clear_hello) (void *target);
>>   void (*clear_tc) (void *target);
>> @@ -134,7 +134,7 @@ const char *get_linkcost_text(olsr_linkcost cost, bool route, struct lqtextbuffe
>> double get_linkcost_scaled(olsr_linkcost cost, bool route);
>> 
>> void olsr_clear_hello_lq(struct link_entry */*link*/);
>> -void olsr_copy_hello_lq(struct lq_hello_neighbor *target, struct link_entry *source);
>> +void olsr_copy_hello_lq(struct lq_hello_neighbor *target, struct link_entry *source, bool force);
>> void olsr_copylq_link_entry_2_tc_mpr_addr(struct tc_mpr_addr *target, struct link_entry *source);
>> void olsr_copylq_link_entry_2_tc_edge_entry(struct tc_edge_entry *target, struct link_entry *source);
>> void olsr_clear_tc_lq(struct tc_mpr_addr *target);
>> diff --git a/src/lq_plugin_default_ff.c b/src/lq_plugin_default_ff.c
>> index 3d6ba6a..fa617e3 100644
>> --- a/src/lq_plugin_default_ff.c
>> +++ b/src/lq_plugin_default_ff.c
>> @@ -70,7 +70,7 @@ static void default_lq_deserialize_hello_lq_pair_ff(const uint8_t ** curr, void
>> static int default_lq_serialize_tc_lq_pair_ff(unsigned char *buff, void *lq);
>> static void default_lq_deserialize_tc_lq_pair_ff(const uint8_t ** curr, void *lq);
>> 
>> -static void default_lq_copy_link2neigh_ff(void *t, void *s);
>> +static void default_lq_copy_link2neigh_ff(void *t, void *s, bool force);
>> static void default_lq_copy_link2tc_ff(void *target, void *source);
>> static void default_lq_clear_ff(void *target);
>> static void default_lq_clear_ff_hello(void *target);
>> @@ -371,11 +371,18 @@ default_lq_memorize_foreign_hello_ff(void *ptrLocal, void *ptrForeign)
>> }
>> 
>> static void
>> -default_lq_copy_link2neigh_ff(void *t, void *s)
>> +default_lq_copy_link2neigh_ff(void *t, void *s, bool force)
>> {
>>   struct default_lq_ff *target = t;
>>   struct default_lq_ff_hello *source = s;
>> -  *target = source->smoothed_lq;
>> +
>> +  if (force) {
>> +    *target = source->smoothed_lq;
>> +    return;
>> +  }
>> +
>> +  target->valueLq = MAX(target->valueLq, source->smoothed_lq.valueLq);
>> +  target->valueNlq = MAX(target->valueNlq, source->smoothed_lq.valueNlq);
>> }
>> 
>> static void
>> diff --git a/src/lq_plugin_default_ffeth.c b/src/lq_plugin_default_ffeth.c
>> index e78dcd7..0e9408e 100644
>> --- a/src/lq_plugin_default_ffeth.c
>> +++ b/src/lq_plugin_default_ffeth.c
>> @@ -72,7 +72,7 @@ static void default_lq_deserialize_hello_lq_pair_ffeth(const uint8_t ** curr, vo
>> static int default_lq_serialize_tc_lq_pair_ffeth(unsigned char *buff, void *lq);
>> static void default_lq_deserialize_tc_lq_pair_ffeth(const uint8_t ** curr, void *lq);
>> 
>> -static void default_lq_copy_link2neigh_ffeth(void *t, void *s);
>> +static void default_lq_copy_link2neigh_ffeth(void *t, void *s, bool force);
>> static void default_lq_copy_link2tc_ffeth(void *target, void *source);
>> static void default_lq_clear_ffeth(void *target);
>> static void default_lq_clear_ffeth_hello(void *target);
>> @@ -410,11 +410,18 @@ default_lq_memorize_foreign_hello_ffeth(void *ptrLocal, void *ptrForeign)
>> }
>> 
>> static void
>> -default_lq_copy_link2neigh_ffeth(void *t, void *s)
>> +default_lq_copy_link2neigh_ffeth(void *t, void *s, bool force)
>> {
>>   struct default_lq_ffeth *target = t;
>>   struct default_lq_ffeth_hello *source = s;
>> -  *target = source->smoothed_lq;
>> +
>> +  if (force) {
>> +    *target = source->smoothed_lq;
>> +    return;
>> +  }
>> +
>> +  target->valueLq = MAX(target->valueLq, source->smoothed_lq.valueLq);
>> +  target->valueNlq = MAX(target->valueNlq, source->smoothed_lq.valueNlq);
>> }
>> 
>> static void
>> diff --git a/src/lq_plugin_default_float.c b/src/lq_plugin_default_float.c
>> index 2e07686..f7e2031 100644
>> --- a/src/lq_plugin_default_float.c
>> +++ b/src/lq_plugin_default_float.c
>> @@ -59,6 +59,7 @@ static int default_lq_serialize_hello_lq_pair_float(unsigned char *buff, void *l
>> static void default_lq_deserialize_hello_lq_pair_float(const uint8_t ** curr, void *lq);
>> static int default_lq_serialize_tc_lq_pair_float(unsigned char *buff, void *lq);
>> static void default_lq_deserialize_tc_lq_pair_float(const uint8_t ** curr, void *lq);
>> +static void default_lq_copy_link2neigh_float(void *t, void *s, bool force);
>> static void default_lq_copy_link2tc_float(void *target, void *source);
>> static void default_lq_clear_float(void *target);
>> static const char *default_lq_print_float(void *ptr, char separator, struct lqtextbuffer *buffer);
>> @@ -74,7 +75,7 @@ struct lq_handler lq_etx_float_handler = {
>> 
>>   &default_lq_packet_loss_worker_float,
>>   &default_lq_memorize_foreign_hello_float,
>> -  &default_lq_copy_link2tc_float,
>> +  &default_lq_copy_link2neigh_float,
>>   &default_lq_copy_link2tc_float,
>>   &default_lq_clear_float,
>>   &default_lq_clear_float,
>> @@ -207,6 +208,22 @@ default_lq_memorize_foreign_hello_float(void *ptrLocal, void *ptrForeign)
>> }
>> 
>> static void
>> +default_lq_copy_link2neigh_float(void *t, void *s, bool force)
>> +{
>> +  struct default_lq_float *target = t;
>> +  struct default_lq_float *source = s;
>> +
>> +  if (force) {
>> +    memcpy(target, source, sizeof(struct default_lq_float));
>> +    return;
>> +  }
>> +
>> +  target->lq = MAX(target->lq, source->lq);
>> +  target->nlq = MAX(target->nlq, source->nlq);
>> +  target->quickstart = MAX(target->quickstart, source->quickstart);
>> +}
>> +
>> +static void
>> default_lq_copy_link2tc_float(void *target, void *source)
>> {
>>   memcpy(target, source, sizeof(struct default_lq_float));
>> diff --git a/src/lq_plugin_default_fpm.c b/src/lq_plugin_default_fpm.c
>> index fbfa0cf..2947f92 100644
>> --- a/src/lq_plugin_default_fpm.c
>> +++ b/src/lq_plugin_default_fpm.c
>> @@ -60,6 +60,7 @@ static int default_lq_serialize_hello_lq_pair_fpm(unsigned char *buff, void *lq)
>> static void default_lq_deserialize_hello_lq_pair_fpm(const uint8_t ** curr, void *lq);
>> static int default_lq_serialize_tc_lq_pair_fpm(unsigned char *buff, void *lq);
>> static void default_lq_deserialize_tc_lq_pair_fpm(const uint8_t ** curr, void *lq);
>> +static void default_lq_copy_link2neigh_fpm(void *t, void *s, bool force);
>> static void default_lq_copy_link2tc_fpm(void *target, void *source);
>> static void default_lq_clear_fpm(void *target);
>> static const char *default_lq_print_fpm(void *ptr, char separator, struct lqtextbuffer *buffer);
>> @@ -75,7 +76,7 @@ struct lq_handler lq_etx_fpm_handler = {
>> 
>>   &default_lq_packet_loss_worker_fpm,
>>   &default_lq_memorize_foreign_hello_fpm,
>> -  &default_lq_copy_link2tc_fpm,
>> +  &default_lq_copy_link2neigh_fpm,
>>   &default_lq_copy_link2tc_fpm,
>>   &default_lq_clear_fpm,
>>   &default_lq_clear_fpm,
>> @@ -224,6 +225,22 @@ default_lq_copy_link2tc_fpm(void *target, void *source)
>> }
>> 
>> static void
>> +default_lq_copy_link2neigh_fpm(void *t, void *s, bool force)
>> +{
>> +  struct default_lq_fpm *target = t;
>> +  struct default_lq_fpm *source = s;
>> +
>> +  if (force) {
>> +    memcpy(target, source, sizeof(struct default_lq_fpm));
>> +    return;
>> +  }
>> +
>> +  target->valueLq = MAX(target->valueLq, source->valueLq);
>> +  target->valueNlq = MAX(target->valueNlq, source->valueNlq);
>> +  target->quickstart = MAX(target->quickstart, source->quickstart);
>> +}
>> +
>> +static void
>> default_lq_clear_fpm(void *target)
>> {
>>   memset(target, 0, sizeof(struct default_lq_fpm));
>> diff --git a/src/olsr_protocol.h b/src/olsr_protocol.h
>> index a995db0..ed3e134 100644
>> --- a/src/olsr_protocol.h
>> +++ b/src/olsr_protocol.h
>> @@ -111,6 +111,83 @@ struct olsr;
>> #define HIDE_LINK             4
>> #define MAX_LINK              4
>> 
>> +/**
>> + * Compare two link types.
>> + *
>> + * <pre>
>> + * +-------------+------+------+--------+------+-----+
>> + * |             |        link_type_new              |
>> + * |             +------+------+--------+------+-----+
>> + * | link_type   | HIDE | LOST | UNSPEC | ASYM | SYM |
>> + * |-------------+------+------+--------+------+-----+
>> + * | HIDE        |  F   |  T   |   T    |  T   |  T  |
>> + * | LOST        |  F   |  F   |   T    |  T   |  T  |
>> + * | UNSPEC      |  F   |  F   |   F    |  T   |  T  |
>> + * | ASYM        |  F   |  F   |   F    |  F   |  T  |
>> + * | SYM         |  F   |  F   |   F    |  F   |  F  |
>> + * +-------------+------+------+--------+------+-----+
>> + * </pre>
>> + *
>> + * @param link_type a link type
>> + * @param link_type_new a (new) link type
>> + * @return true when link_type_new is 'better' than link_type
>> + */
>> +static INLINE bool link_type_compare(int link_type, int link_type_new) {
>> +  switch (link_type_new) {
>> +    case SYM_LINK:
>> +      switch (link_type) {
>> +        case SYM_LINK:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    case ASYM_LINK:
>> +      switch (link_type) {
>> +        case SYM_LINK:
>> +        case ASYM_LINK:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    case UNSPEC_LINK:
>> +      switch (link_type) {
>> +        case SYM_LINK:
>> +        case ASYM_LINK:
>> +        case UNSPEC_LINK:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    case LOST_LINK:
>> +      switch (link_type) {
>> +        case SYM_LINK:
>> +        case ASYM_LINK:
>> +        case UNSPEC_LINK:
>> +        case LOST_LINK:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    case HIDE_LINK:
>> +      return false;
>> +
>> +    default:
>> +      return true;
>> +  }
>> +}
>> +
>> static INLINE const char * linkTypeToString(int type) {
>>   switch (type) {
>>     case ASYM_LINK:
>> @@ -140,6 +217,65 @@ static INLINE const char * linkTypeToString(int type) {
>> #define MPR_NEIGH             2
>> #define MAX_NEIGH             2
>> 
>> +/**
>> + * Compare two neighbour types.
>> + *
>> + * <pre>
>> + * +-------+------+-----+-----+
>> + * |       |     neigh_new    |
>> + * |       +------+-----+-----+
>> + * | neigh | NOT  | SYM | MPR |
>> + * |-------+------+-----+-----+
>> + * | NOT   |  F   |  T  |  T  |
>> + * | SYM   |  F   |  F  |  T  |
>> + * | MPR   |  F   |  F  |  F  |
>> + * +-------+------+-----+-----+
>> + * </pre>
>> + *
>> + * @param neigh a neighbour type
>> + * @param neigh_new a (new) neighbour type
>> + * @return true when neigh_new is 'better' than neigh
>> + */
>> +static INLINE bool neigh_type_compare(int neigh, int neigh_new) {
>> +  switch (neigh_new) {
>> +    case MPR_NEIGH:
>> +      switch (neigh) {
>> +        case MPR_NEIGH:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    case SYM_NEIGH:
>> +      switch (neigh) {
>> +        case MPR_NEIGH:
>> +        case SYM_NEIGH:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    case NOT_NEIGH:
>> +      switch (neigh) {
>> +        case MPR_NEIGH:
>> +        case SYM_NEIGH:
>> +        case NOT_NEIGH:
>> +          return false;
>> +
>> +        default:
>> +          return true;
>> +      }
>> +      break;
>> +
>> +    default:
>> +      return true;
>> +  }
>> +}
>> +
>> /*
>>  *Neighbor status
>>  */
>> 
> 
> -- 
> Ferry Huberts


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