Commit 5ae13e15 authored by Ondrej Zajicek (work)'s avatar Ondrej Zajicek (work)
Browse files

Nest: Change nexthop merging order to prefer earlier nexthops 

When nexthop merge limit was applied, the old code used first N nexthops
in the canonical ordering. Now the code prefers nexthops based on the
order or routes in the network.
parent 00cf501a

nest/route.h

+1 −0
Original line number Diff line number Diff line
@@ -638,6 +638,7 @@ int nexthop__same(struct nexthop *x, struct nexthop *y); /* Compare multipath ne 
static inline int nexthop_same(struct nexthop *x, struct nexthop *y)

{ return (x == y) || nexthop__same(x, y); }

struct nexthop *nexthop_merge(struct nexthop *x, struct nexthop *y, int rx, int ry, int max, linpool *lp);

struct nexthop *nexthop_merge2(struct nexthop *x, struct nexthop *y, int ry, int *max, linpool *lp);

static inline void nexthop_link(struct rta *a, struct nexthop *from)

{ memcpy(&a->nh, from, nexthop_size(from)); }

void nexthop_insert(struct nexthop **n, struct nexthop *y);

nest/rt-attr.c

+51 −0
Original line number Diff line number Diff line
@@ -285,6 +285,57 @@ nexthop_merge(struct nexthop *x, struct nexthop *y, int rx, int ry, int max, lin 
  return root;

}



/**

 * nexthop_merge2 - merge nexthop lists

 * @x: list 1

 * @y: list 2

 * @ry: reusability of list @y

 * @max: max number of added nexthops

 * @lp: linpool for allocating nexthops

 *

 * The nexthop_merge2() function takes two nexthop lists @x and @y and merges

 * them, eliminating possible duplicates. It is a variant of nexthop_merge()

 * function differing in how @max limit is handled, here it limits just number

 * of nexthops added from the second list @y. The @max value is decreased with

 * each such nexthop, this return remaining 'unused' limit, which can be used in

 * subsequent calls. The list @x is expected to be an accumulator and its

 * reusability is implied.  New nodes are allocated from linpool @lp.

 */

struct nexthop *

nexthop_merge2(struct nexthop *x, struct nexthop *y, int ry, int *max, linpool *lp)

{

  struct nexthop *root = NULL;

  struct nexthop **n = &root;



  if (*max <= 0)

    return x;



  while (x || y)

  {

    int cmp = nexthop_compare_node(x, y);

    if (cmp < 0)

    {

      *n = x;

      x = x->next;

    }

    else if (cmp > 0)

    {

      *n = ry ? y : nexthop_copy_node(y, lp);

      y = (--*max) ? y->next : NULL;

    }

    else

    {

      *n = x;

      x = x->next;

      y = y->next;

    }

    n = &((*n)->next);

  }

  *n = NULL;



  return root;

}



void

nexthop_insert(struct nexthop **n, struct nexthop *x)

{

nest/rt-table.c

+8 −19
Original line number Diff line number Diff line
@@ -849,18 +849,13 @@ rt_notify_accepted(struct channel *c, net *net, rte *new_changed, rte *old_chang 
}





static struct nexthop *

nexthop_merge_rta(struct nexthop *nhs, rta *a, linpool *pool, int max)

{

  return nexthop_merge(nhs, &(a->nh), 1, 0, max, pool);

}



rte *

rt_export_merged(struct channel *c, net *net, rte **rt_free, ea_list **tmpa, linpool *pool, int silent)

{

  // struct proto *p = c->proto;

  struct nexthop *nhs = NULL;

  rte *best0, *best, *rt0, *rt, *tmp;

  int max = c->merge_limit;



  best0 = net->routes;

  *rt_free = NULL;
@@ -870,10 +865,12 @@ rt_export_merged(struct channel *c, net *net, rte **rt_free, ea_list **tmpa, lin 


  best = export_filter_(c, best0, rt_free, tmpa, pool, silent);



  if (!best || !rte_is_reachable(best))

  if (!best || !rte_is_reachable(best) || !best0->next)

    return best;



  for (rt0 = best0->next; rt0; rt0 = rt0->next)

  nhs = nexthop_merge2(NULL, &(best->attrs->nh), 0, &max, pool);



  for (rt0 = best0->next; rt0 && max; rt0 = rt0->next)

  {

    if (!rte_mergable(best0, rt0))

      continue;
@@ -884,22 +881,14 @@ rt_export_merged(struct channel *c, net *net, rte **rt_free, ea_list **tmpa, lin 
      continue;



    if (rte_is_reachable(rt))

      nhs = nexthop_merge_rta(nhs, rt->attrs, pool, c->merge_limit);

      nhs = nexthop_merge2(nhs, &(rt->attrs->nh), 0, &max, pool);



    if (tmp)

      rte_free(tmp);

  }



  if (nhs)

  {

    nhs = nexthop_merge_rta(nhs, best->attrs, pool, c->merge_limit);



    if (nhs->next)

    {

  best = rte_cow_rta(best, pool);

  nexthop_link(best->attrs, nhs);

    }

  }



  if (best != best0)

    *rt_free = best;

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