bird/proto/ospf/topology.c

/*
 *	BIRD -- OSPF Topological Database
 *
 *	(c) 1999        Martin Mares <mj@ucw.cz>
 *	(c) 1999 - 2000 Ondrej Filip <feela@network.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "nest/bird.h"
#include "lib/string.h"

#include "ospf.h"

#define HASH_DEF_ORDER 6
#define HASH_HI_MARK *4
#define HASH_HI_STEP 2
#define HASH_HI_MAX 16
#define HASH_LO_MARK /5
#define HASH_LO_STEP 2
#define HASH_LO_MIN 8

void *
originate_rt_lsa_body(struct ospf_area *oa, u16 *length, struct proto_ospf *p)
{
  struct ospf_iface *ifa;
  int j=0,k=0,v=0;
  u16 i=0;
  struct ospf_lsa_rt *rt;
  struct ospf_lsa_rt_link *ln;
  struct ospf_neighbor *neigh;
  struct top_hash_entry *old;
  struct proto_ospf *po=(struct proto_ospf *)p;

  DBG("%s: Originating RT_lsa body for area \"%I\".\n", po->proto.name,
    oa->areaid);

  WALK_LIST (ifa, p->iface_list)
  {
    if((ifa->an==oa->areaid) && (ifa->state!=OSPF_IS_DOWN))
    {
      i++;
      if(ifa->type==OSPF_IT_VLINK) v=1;
    }
  }
  rt=mb_allocz(p->proto.pool, sizeof(struct ospf_lsa_rt)+
    i*sizeof(struct ospf_lsa_rt_link));
  if(p->areano>1) rt->veb.bit.b=1;
  if((p->ebit)&&(!oa->stub)) rt->veb.bit.e=1;
  rt->veb.bit.v=v;
  ln=(struct ospf_lsa_rt_link *)(rt+1);

  WALK_LIST (ifa, p->iface_list)
  {
    if((ifa->an!=oa->areaid) || (ifa->state==OSPF_IS_DOWN)) continue;

    if(ifa->state==OSPF_IS_LOOP)
    {
      ln->type=3;
      ln->id=ipa_to_u32(ifa->iface->addr->ip);
      ln->data=0xffffffff;
      ln->metric=0;
      ln->notos=0;
    }
    else
    {
      switch(ifa->type)
      {
        case OSPF_IT_PTP:		/* rfc2328 - pg126 */
          neigh=(struct ospf_neighbor *)HEAD(ifa->neigh_list);
          if((!EMPTY_LIST(ifa->neigh_list)) && (neigh->state==NEIGHBOR_FULL))
          {
             ln->type=LSART_PTP;
             ln->id=neigh->rid;
             ln->metric=ifa->cost;
             ln->notos=0;
             if(ifa->iface->flags && IA_UNNUMBERED)
             {
               ln->data=ifa->iface->index;
             }
             else
             {
               ln->id=ipa_to_u32(ifa->iface->addr->ip);
             }
          }
          else
          {
            if(ifa->state==OSPF_IS_PTP)
            {
              ln->type=LSART_STUB;
              ln->id=ln->id=ipa_to_u32(ifa->iface->addr->opposite);
              ln->metric=ifa->cost;
              ln->notos=0;
              ln->data=0xffffffff;
            }
            else
            {
              i--; /* No link added */
            }
          }
          break;
        case OSPF_IT_BCAST:
        case OSPF_IT_NBMA:
          if(ifa->state==OSPF_IS_WAITING)
          {
            ln->type=LSART_STUB;
            ln->id=ipa_to_u32(ifa->iface->addr->prefix);
            ln->data=ipa_to_u32(ipa_mkmask(ifa->iface->addr->pxlen));
            ln->metric=ifa->cost;
            ln->notos=0;
          }
          else
          {
            j=0,k=0;
            WALK_LIST(neigh, ifa->neigh_list)
            {
              if((neigh->rid==ifa->drid) &&
                (neigh->state==NEIGHBOR_FULL)) k=1;
              if(neigh->state==NEIGHBOR_FULL) j=1;
            }
            if(((ifa->state==OSPF_IS_DR) && (j==1)) || (k==1))
            {
              ln->type=LSART_NET;
              ln->id=ipa_to_u32(ifa->drip);
              ln->data=ipa_to_u32(ifa->iface->addr->ip);
              ln->metric=ifa->cost;
              ln->notos=0;
            }
            else
            {
              ln->type=LSART_STUB;
              ln->id=ipa_to_u32(ifa->iface->addr->prefix);
              ln->data=ipa_to_u32(ipa_mkmask(ifa->iface->addr->pxlen));
              ln->metric=ifa->cost;
              ln->notos=0;
            }
          }
          break;
        case OSPF_IT_VLINK:	/* FIXME Add virtual links! */
          i--;
          break;
      }
    }
    if(ifa->type==OSPF_IT_VLINK) v=1;
    ln=(ln+1);
  }
  rt->links=i;
  *length=i*sizeof(struct ospf_lsa_rt_link)+sizeof(struct ospf_lsa_rt)+
    sizeof(struct ospf_lsa_header);
  return rt;
}

void
addifa_rtlsa(struct ospf_iface *ifa)
{
  struct ospf_area *oa;
  struct proto_ospf *po=ifa->proto;
  struct proto *p=&po->proto;


  WALK_LIST(NODE oa,po->area_list)
  {
    if(oa->areaid==ifa->an) break;
  }

  if(EMPTY_LIST(po->area_list) || (oa->areaid!=ifa->an))	/* New area */
  {
    bug("Cannot add any area to accepted Interface");
  }
  else ifa->oa=oa;
}

/**
 * originate_rt_lsa - build new instance of router LSA
 * @oa: ospf_area which is LSA built to
 *
 * It builds router LSA walking through all OSPF interfaces in
 * specified OSPF area. This function is mostly called from
 * area_disp(). Builds new LSA, increases sequence number (if old
 * instance exists) and sets age of LSA to zero.
 */
void
originate_rt_lsa(struct ospf_area *oa)
{
  struct ospf_lsa_header lsa;
  struct proto_ospf *po=oa->po;
  struct proto *p=&po->proto;
  u32 rtid=po->proto.cf->global->router_id;
  struct top_hash_entry *en;
  void *body;

  if((oa->rt)&&((oa->rt->inst_t+MINLSINTERVAL))>now) return;
	/*
         * Tick is probably set to very low value. We cannot
	 * originate new LSA before MINLSINTERVAL. We will
	 * try to do it next tick.
         */

  OSPF_TRACE(D_EVENTS, "Originating RT_lsa for area \"%I\".",oa->areaid);

  lsa.age=0;
  lsa.id=rtid;
  lsa.type=LSA_T_RT;
  lsa.rt=rtid;
  lsa.options=0;
  if(oa->rt==NULL)
  {
    lsa.sn=LSA_INITSEQNO;
  }
  else
  {
    lsa.sn=oa->rt->lsa.sn+1;
  }
  body=originate_rt_lsa_body(oa, &lsa.length, po);
  lsasum_calculate(&lsa,body,po);
  en=lsa_install_new(&lsa, body, oa);
  oa->rt=en;
  flood_lsa(NULL,NULL,&oa->rt->lsa,po,NULL,oa,1);
  schedule_rtcalc(oa);
  oa->origrt=0;
}

void *
originate_net_lsa_body(struct ospf_iface *ifa, u16 *length,
  struct proto_ospf *po)
{
  u16 i=1;
  struct ospf_neighbor *n;
  u32 *body;
  struct ospf_lsa_net *net;

  net=mb_alloc(po->proto.pool,sizeof(u32)*(ifa->fadj+1)+
    sizeof(struct ospf_lsa_net));
  net->netmask=ipa_mkmask(ifa->iface->addr->pxlen);

  body=(u32 *)(net+1);
  i=1;
  *body=po->proto.cf->global->router_id;
  WALK_LIST(n,ifa->neigh_list)
  {
    if(n->state==NEIGHBOR_FULL)
    {
      *(body+i)=n->rid;
      i++;
    }
  }
  *length=i*sizeof(u32)+sizeof(struct ospf_lsa_header)+
    sizeof(struct ospf_lsa_net);
  return net;
}

/**
 * originate_net_lsa - originates of deletes network LSA
 * @ifa: interface which is LSA originated for
 *
 * Interface counts number of adjacent neighbors. If this number is
 * lower than one or interface is not in state %OSPF_IS_DR it deletes
 * and premature ages instance of network LSA for specified interface.
 * In other case, new instance of network LSA is originated.
 */
void
originate_net_lsa(struct ospf_iface *ifa)
{
  struct proto_ospf *po=ifa->proto;
  struct ospf_lsa_header lsa;
  u32 rtid=po->proto.cf->global->router_id;
  struct top_hash_entry *en;
  struct proto *p=&po->proto;
  void *body;

  if(ifa->nlsa&&((ifa->nlsa->inst_t+MINLSINTERVAL)>now)) return;
  /*
   * It's too early to originate new network LSA. We will
   * try to do it next tick
   */

  if((ifa->state!=OSPF_IS_DR)||(ifa->fadj==0))
  {
    if(ifa->nlsa==NULL) return;

    OSPF_TRACE(D_EVENTS, "Deleting Net lsa for iface \"%s\".",
      ifa->iface->name);
    ifa->nlsa->lsa.sn+=1;
    ifa->nlsa->lsa.age=LSA_MAXAGE;
    flood_lsa(NULL,NULL,&ifa->nlsa->lsa,po,NULL,ifa->oa,0);
    s_rem_node(SNODE ifa->nlsa);
    ospf_hash_delete(ifa->oa->gr, ifa->nlsa);
    schedule_rtcalc(ifa->oa);
    ifa->nlsa=NULL;
    return ;
  }

  OSPF_TRACE(D_EVENTS, "Originating Net lsa for iface \"%s\".",
    ifa->iface->name);

  lsa.age=0;
  lsa.id=ipa_to_u32(ifa->iface->addr->ip);
  lsa.type=LSA_T_NET;
  lsa.rt=rtid;
  lsa.options=0;
  if(ifa->nlsa==NULL)
  {
    lsa.sn=LSA_INITSEQNO;
  }
  else
  {
    lsa.sn=ifa->nlsa->lsa.sn+1;
  }

  body=originate_net_lsa_body(ifa, &lsa.length, po);
  lsasum_calculate(&lsa,body,po);
  ifa->nlsa=lsa_install_new(&lsa, body, ifa->oa);
  flood_lsa(NULL,NULL,&ifa->nlsa->lsa,po,NULL,ifa->oa,1);
  ifa->orignet=0;
}

static void *
originate_ext_lsa_body(net *n, rte *e, struct proto_ospf *po, struct ea_list *attrs)
{
  struct proto *p=&po->proto;
  struct ospf_lsa_ext *ext;
  struct ospf_lsa_ext_tos *et;
  neighbor *nn;
  u32 m1 = ea_get_int(attrs, EA_OSPF_METRIC1, LSINFINITY);
  u32 m2 = ea_get_int(attrs, EA_OSPF_METRIC2, 10000);
  u32 tag = ea_get_int(attrs, EA_OSPF_TAG, 0);
  int inas=0;

  ext=mb_alloc(p->pool,sizeof(struct ospf_lsa_ext)+
    sizeof(struct ospf_lsa_ext_tos));
  ext->netmask=ipa_mkmask(n->n.pxlen);

  et=(struct ospf_lsa_ext_tos *)(ext+1);

  if(m1!=LSINFINITY)
  {
    et->etos=0;
    et->metric=m1;
  }
  else
  {
    et->etos=0x80;
    et->metric=m2;
  }
  et->padding=0;
  et->tag=tag;
  if(ipa_compare(e->attrs->gw,ipa_from_u32(0))!=0)
  {
    if(find_iface((struct proto_ospf *)p, e->attrs->iface)!=NULL) inas=1;
  }
    
  if(!inas) et->fwaddr= ipa_from_u32(0);
  else et->fwaddr=e->attrs->gw;
  return ext;
}

/**
 * max_ext_lsa - calculate the maximum amount of external networks
 * possible for the given prefix length.
 *
 * This is a fix for the previous static use of MAXNETS which did
 * only work correct if MAXNETS < possible IPs for given prefix.
 * This solution is kind of a hack as there can now only be one
 * route for /32 type entries but this is better than the crashes
 * I did experience whith close together /32 routes originating
 * on different hosts.
 */

int
max_ext_lsa(unsigned pxlen)
{
  int i;
  for(i=1;pxlen<BITS_PER_IP_ADDRESS;pxlen++,i<<=1)
    if(i>=MAXNETS)
      return MAXNETS;
  return i;
}

/**
 * originate_ext_lsa - new route received from nest and filters
 * @n: network prefix and mask
 * @e: rte
 * @po: current instance of OSPF
 * @attrs: list of extended attributes
 *
 * If I receive a message that new route is installed, I try to originate an
 * external LSA. The LSA header of such LSA does not contain information about
 * prefix length, so if I have to originate multiple LSAs for route with
 * different prefixes I try to increment prefix id to find a "free" one.
 *
 * The function also sets flag ebit. If it's the first time, the new router lsa
 * origination is necessary.
 */
void
originate_ext_lsa(net *n, rte *e, struct proto_ospf *po, struct ea_list *attrs)
{
  struct ospf_lsa_header lsa;
  u32 rtid=po->proto.cf->global->router_id;
  struct top_hash_entry *en=NULL;
  void *body=NULL;
  struct proto *p=&po->proto;
  struct ospf_area *oa;
  struct ospf_lsa_ext *ext1,*ext2;
  int i;
  int max;

  OSPF_TRACE(D_EVENTS, "Originating Ext lsa for %I/%d.", n->n.prefix,
    n->n.pxlen);

  lsa.age=0;
  lsa.id=ipa_to_u32(n->n.prefix);
  lsa.type=LSA_T_EXT;
  lsa.rt=rtid;
  lsa.sn=LSA_INITSEQNO;
  body=originate_ext_lsa_body(n, e, po, attrs);
  lsa.length=sizeof(struct ospf_lsa_ext)+sizeof(struct ospf_lsa_ext_tos)+
    sizeof(struct ospf_lsa_header);
  ext1=body;
  max=max_ext_lsa(n->n.pxlen);

  oa=HEAD(po->area_list);

  for(i=0;i<max;i++)
  {
    if((en=ospf_hash_find_header(oa->gr, &lsa))!=NULL)
    {
      ext2=en->lsa_body;
      if(ipa_compare(ext1->netmask,ext2->netmask)!=0) lsa.id++;
      else break;
    }
    else break;
  }

  if(i==max)
  {
    log("%s: got more routes for one /%d network then %d, ignoring",p->name,
      n->n.pxlen,max);
    mb_free(body);
    return;
  }
  lsasum_calculate(&lsa,body,po);
  WALK_LIST(oa, po->area_list)
  {
    en=lsa_install_new(&lsa, body, oa);
    flood_lsa(NULL,NULL,&en->lsa,po,NULL,oa,1);
    body=originate_ext_lsa_body(n, e, po, attrs);
  }
  mb_free(body);

  if(po->ebit==0)
  {
    po->ebit=1;
    WALK_LIST(oa, po->area_list)
    {
      schedule_rt_lsa(oa);
    }
  }
}


static void
ospf_top_ht_alloc(struct top_graph *f)
{
  f->hash_size = 1 << f->hash_order;
  f->hash_mask = f->hash_size - 1;
  if (f->hash_order > HASH_HI_MAX - HASH_HI_STEP)
    f->hash_entries_max = ~0;
  else
    f->hash_entries_max = f->hash_size HASH_HI_MARK;
  if (f->hash_order < HASH_LO_MIN + HASH_LO_STEP)
    f->hash_entries_min = 0;
  else
    f->hash_entries_min = f->hash_size HASH_LO_MARK;
  DBG("Allocating OSPF hash of order %d: %d hash_entries, %d low, %d high\n",
      f->hash_order, f->hash_size, f->hash_entries_min, f->hash_entries_max);
  f->hash_table = mb_alloc(f->pool, f->hash_size * sizeof(struct top_hash_entry *));
  bzero(f->hash_table, f->hash_size * sizeof(struct top_hash_entry *));
}

static inline void
ospf_top_ht_free(struct top_hash_entry **h)
{
  mb_free(h);
}

static inline u32
ospf_top_hash_u32(u32 a)
{
  /* Shamelessly stolen from IP address hashing in ipv4.h */
  a ^= a >> 16;
  a ^= a << 10;
  return a;
}

static inline unsigned
ospf_top_hash(struct top_graph *f, u32 lsaid, u32 rtrid, u32 type)
{
#if 1	/* Dirty patch to make rt table calculation work. */
return (ospf_top_hash_u32(lsaid) + ospf_top_hash_u32((type==LSA_T_NET) ? lsaid : rtrid) + type) & f->hash_mask;
#else
  return (ospf_top_hash_u32(lsaid) + ospf_top_hash_u32(rtrid) + type) & f->hash_mask;
#endif
}

/**
 * ospf_top_new - allocated new topology database
 * @p: current instance of OSPF
 *
 * This dynamically hashed structure is often used for keeping LSAs. Mainly
 * its used in @ospf_area structure.
 */
struct top_graph *
ospf_top_new(struct proto_ospf *p)
{
  struct top_graph *f;

  f = mb_allocz(p->proto.pool, sizeof(struct top_graph));
  f->pool = p->proto.pool;
  f->hash_slab = sl_new(f->pool, sizeof(struct top_hash_entry));
  f->hash_order = HASH_DEF_ORDER;
  ospf_top_ht_alloc(f);
  f->hash_entries = 0;
  f->hash_entries_min = 0;
  return f;
}

void
ospf_top_free(struct top_graph *f)
{
  rfree(f->hash_slab);
  ospf_top_ht_free(f->hash_table);
  mb_free(f);
}

static void
ospf_top_rehash(struct top_graph *f, int step)
{
  unsigned int oldn, oldh;
  struct top_hash_entry **n, **oldt, **newt, *e, *x;

  oldn = f->hash_size;
  oldt = f->hash_table;
  DBG("Re-hashing topology hash from order %d to %d\n", f->hash_order, f->hash_order+step);
  f->hash_order += step;
  ospf_top_ht_alloc(f);
  newt = f->hash_table;

  for(oldh=0; oldh < oldn; oldh++)
    {
      e = oldt[oldh];
      while (e)
	{
	  x = e->next;
	  n = newt + ospf_top_hash(f, e->lsa.id, e->lsa.rt, e->lsa.type);
	  e->next = *n;
	  *n = e;
	  e = x;
	}
    }
  ospf_top_ht_free(oldt);
}

struct top_hash_entry *
ospf_hash_find_header(struct top_graph *f, struct ospf_lsa_header *h)
{
  return ospf_hash_find(f,h->id,h->rt,h->type);
}

struct top_hash_entry *
ospf_hash_get_header(struct top_graph *f, struct ospf_lsa_header *h)
{
  return ospf_hash_get(f,h->id,h->rt,h->type);
}

struct top_hash_entry *
ospf_hash_find(struct top_graph *f, u32 lsa, u32 rtr, u32 type)
{
  struct top_hash_entry *e = f->hash_table[ospf_top_hash(f, lsa, rtr, type)];

#if 1	/* Dirty patch to make rt table calculation work. */
  if(type==LSA_T_NET)
  {
    while (e && (e->lsa.id != lsa || e->lsa.type != LSA_T_NET ))
       e = e->next;
  }
  else
  {
     while (e && (e->lsa.id != lsa || e->lsa.type != type || e->lsa.rt != rtr))
       e = e->next;
  }
#else
  while (e && (e->lsa.id != lsa || e->lsa.rt != rtr || e->lsa.type != type))
    e = e->next;
#endif
  return e;
}

struct top_hash_entry *
ospf_hash_get(struct top_graph *f, u32 lsa, u32 rtr, u32 type)
{
  struct top_hash_entry **ee = f->hash_table + ospf_top_hash(f, lsa, rtr, type);
  struct top_hash_entry *e = *ee;

  while (e && (e->lsa.id != lsa || e->lsa.rt != rtr || e->lsa.type != type))
    e = e->next;
  if (e)
    return e;
  e = sl_alloc(f->hash_slab);
  e->lsa.id = lsa;
  e->lsa.rt = rtr;
  e->lsa.type = type;
  e->lsa_body = NULL;
  e->nhi=NULL;
  e->next=*ee;		/* MJ you forgot this :-) */
  *ee=e;
  if (f->hash_entries++ > f->hash_entries_max)
    ospf_top_rehash(f, HASH_HI_STEP);
  return e;
}

void
ospf_hash_delete(struct top_graph *f, struct top_hash_entry *e)
{
  unsigned int h = ospf_top_hash(f, e->lsa.id, e->lsa.rt, e->lsa.type);
  struct top_hash_entry **ee = f->hash_table + h;

  while (*ee)
    {
      if (*ee == e)
	{
	  *ee = e->next;
	  sl_free(f->hash_slab, e);
	  if (f->hash_entries-- < f->hash_entries_min)
	    ospf_top_rehash(f, -HASH_LO_STEP);
	  return;
	}
      ee = &((*ee)->next);
    }
  bug("ospf_hash_delete() called for invalid node");
}

void
ospf_top_dump(struct top_graph *f, struct proto *p)
{
  unsigned int i;
  OSPF_TRACE(D_EVENTS, "Hash entries: %d", f->hash_entries);

  for(i=0; i<f->hash_size; i++)
    {
      struct top_hash_entry *e = f->hash_table[i];
      while (e)
	{
	  OSPF_TRACE(D_EVENTS, "\t%1x %-1I %-1I %4u 0x%08x",
	    e->lsa.type, e->lsa.id,
            e->lsa.rt, e->lsa.age, e->lsa.sn);
	  e = e->next;
	}
    }
}

/* This is very inefficient, please don't call it often */

/* I should also test for every LSA if it's in some link state
 * retransmission list for every neighbor. I will not test it.
 * It could happen that I'll receive some strange ls ack's.
 */

int
can_flush_lsa(struct ospf_area *oa)
{
  struct ospf_iface *ifa;
  struct ospf_neighbor *n;
  struct proto_ospf *po=oa->po;

  WALK_LIST(ifa, iface_list)
  {
    if(ifa->oa==oa)
    {
      WALK_LIST(n, ifa->neigh_list)
      {
        if((n->state==NEIGHBOR_EXCHANGE)||(n->state==NEIGHBOR_LOADING))
	{
	  return 0;
	}
      }
    }
  }

  return 1;
}