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labs-bird/proto/ospf/hello.c

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/*
* BIRD -- OSPF
*
* (c) 1999--2004 Ondrej Filip <feela@network.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "ospf.h"
#ifdef OSPFv2
struct ospf_hello_packet
{
struct ospf_packet ospf_packet;
ip_addr netmask;
u16 helloint;
u8 options;
u8 priority;
u32 deadint;
u32 dr;
u32 bdr;
};
#endif
#ifdef OSPFv3
struct ospf_hello_packet
{
struct ospf_packet ospf_packet;
u32 iface_id;
u8 priority;
u8 options3;
u8 options2;
u8 options;
u16 helloint;
u16 deadint;
u32 dr;
u32 bdr;
};
#endif
void
ospf_hello_receive(struct ospf_packet *ps_i, struct ospf_iface *ifa,
struct ospf_neighbor *n, ip_addr faddr)
{
struct proto *p = &ifa->oa->po->proto;
char *beg = "Bad OSPF HELLO packet from ", *rec = " received: ";
unsigned int size, i, twoway, oldpriority, eligible, peers;
u32 olddr, oldbdr, oldiface_id, tmp;
u32 *pnrid;
size = ntohs(ps_i->length);
if (size < sizeof(struct ospf_hello_packet))
{
log(L_ERR "%s%I - too short (%u B)", beg, faddr, size);
return;
}
struct ospf_hello_packet *ps = (void *) ps_i;
OSPF_TRACE(D_PACKETS, "HELLO packet received from %I via %s%s", faddr,
(ifa->type == OSPF_IT_VLINK ? "vlink-" : ""), ifa->iface->name);
#ifdef OSPFv2
ip_addr mask = ps->netmask;
ipa_ntoh(mask);
if (ifa->type != OSPF_IT_VLINK)
{
char *msg = L_WARN "Received HELLO packet %s (%I) is inconsistent "
"with the primary address of interface %s.";
if ((ifa->type != OSPF_IT_PTP) &&
!ipa_equal(mask, ipa_mkmask(ifa->iface->addr->pxlen)))
{
if (!n) log(msg, "netmask", mask, ifa->iface->name);
return;
}
/* This check is not specified in RFC 2328, but it is needed
* to handle the case when there is more IP networks on one
* physical network (which is not handled in RFC 2328).
* We allow OSPF on primary IP address only and ignore HELLO packets
* with secondary addresses (which are sent for example by Quagga.
*/
if ((ifa->iface->addr->flags & IA_UNNUMBERED) ?
!ipa_equal(faddr, ifa->iface->addr->opposite) :
!ipa_equal(ipa_and(faddr,mask), ifa->iface->addr->prefix))
{
if (!n) log(msg, "address", faddr, ifa->iface->name);
return;
}
}
#endif
tmp = ntohs(ps->helloint);
if (tmp != ifa->helloint)
{
log(L_ERR "%s%I%shello interval mismatch (%d).", beg, faddr, rec, tmp);
return;
}
#ifdef OSPFv2
tmp = ntohl(ps->deadint);
#else /* OSPFv3 */
tmp = ntohs(ps->deadint);
#endif
if (tmp != ifa->dead)
{
log(L_ERR "%s%I%sdead interval mismatch (%d).", beg, faddr, rec, tmp);
return;
}
tmp = !(ps->options & OPT_E);
if (tmp != ifa->oa->stub)
{
log(L_ERR "%s%I%sstub area flag mismatch (%d).", beg, faddr, rec, tmp);
return;
}
if (!n)
{
if ((ifa->type == OSPF_IT_NBMA))
{
struct nbma_node *nn;
int found = 0;
WALK_LIST(nn, ifa->nbma_list)
{
if (ipa_equal(faddr, nn->ip))
{
found = 1;
break;
}
}
if ((found == 0) && (ifa->strictnbma))
{
log(L_WARN "Ignoring new neighbor: %I on %s.", faddr,
ifa->iface->name);
return;
}
if (found)
{
eligible = nn->eligible;
if (((ps->priority == 0) && eligible)
|| ((ps->priority > 0) && (eligible == 0)))
{
log(L_ERR "Eligibility mismatch for neighbor: %I on %s",
faddr, ifa->iface->name);
return;
}
}
}
OSPF_TRACE(D_EVENTS, "New neighbor found: %I on %s.", faddr,
ifa->iface->name);
n = ospf_neighbor_new(ifa);
n->rid = ntohl(((struct ospf_packet *) ps)->routerid);
n->ip = faddr;
n->dr = ntohl(ps->dr);
n->bdr = ntohl(ps->bdr);
n->priority = ps->priority;
#ifdef OSPFv3
n->iface_id = ntohl(ps->iface_id);
#endif
}
ospf_neigh_sm(n, INM_HELLOREC);
pnrid = (u32 *) ((struct ospf_hello_packet *) (ps + 1));
peers = (size - sizeof(struct ospf_hello_packet))/ sizeof(u32);
twoway = 0;
for (i = 0; i < peers; i++)
{
if (ntohl(*(pnrid + i)) == p->cf->global->router_id)
{
DBG("%s: Twoway received from %I\n", p->name, faddr);
ospf_neigh_sm(n, INM_2WAYREC);
twoway = 1;
break;
}
}
if (!twoway)
ospf_neigh_sm(n, INM_1WAYREC);
olddr = n->dr;
oldbdr = n->bdr;
oldpriority = n->priority;
#ifdef OSPFv3
oldiface_id = n->iface_id;
#endif
n->dr = ntohl(ps->dr);
n->bdr = ntohl(ps->bdr);
n->priority = ps->priority;
#ifdef OSPFv3
n->iface_id = ntohl(ps->iface_id);
#endif
/* Check priority change */
if (n->state >= NEIGHBOR_2WAY)
{
#ifdef OSPFv2
u32 rid = ipa_to_u32(n->ip);
#else /* OSPFv3 */
u32 rid = p->cf->global->router_id;
#endif
if (n->priority != oldpriority)
ospf_iface_sm(ifa, ISM_NEICH);
#ifdef OSPFv3
if (n->iface_id != oldiface_id)
ospf_iface_sm(ifa, ISM_NEICH);
#endif
/* Router is declaring itself ad DR and there is no BDR */
if ((rid == n->dr) && (n->bdr == 0)
&& (n->state != NEIGHBOR_FULL))
ospf_iface_sm(ifa, ISM_BACKS);
/* Neighbor is declaring itself as BDR */
if ((rid == n->bdr) && (n->state != NEIGHBOR_FULL))
ospf_iface_sm(ifa, ISM_BACKS);
/* Neighbor is newly declaring itself as DR or BDR */
if (((rid == n->dr) && (n->dr != olddr))
|| ((rid == n->bdr) && (n->bdr != oldbdr)))
ospf_iface_sm(ifa, ISM_NEICH);
/* Neighbor is no more declaring itself as DR or BDR */
if (((rid == olddr) && (n->dr != olddr))
|| ((rid == oldbdr) && (n->bdr != oldbdr)))
ospf_iface_sm(ifa, ISM_NEICH);
}
if (ifa->type == OSPF_IT_NBMA)
{
if ((ifa->priority == 0) && (n->priority > 0))
ospf_hello_send(NULL, 0, n);
}
ospf_neigh_sm(n, INM_HELLOREC);
}
void
ospf_hello_send(timer *timer, int poll, struct ospf_neighbor *dirn)
{
struct ospf_iface *ifa;
struct ospf_hello_packet *pkt;
struct ospf_packet *op;
struct proto *p;
struct ospf_neighbor *neigh, *n1;
u16 length;
u32 *pp;
int i, send;
struct nbma_node *nb;
if (timer == NULL)
ifa = dirn->ifa;
else
ifa = (struct ospf_iface *) timer->data;
if (ifa->state == OSPF_IS_DOWN)
return;
if (ifa->stub)
return; /* Don't send any packet on stub iface */
p = (struct proto *) (ifa->oa->po);
DBG("%s: Hello/Poll timer fired on interface %s.\n",
p->name, ifa->iface->name);
/* Now we should send a hello packet */
pkt = (struct ospf_hello_packet *) (ifa->sk->tbuf);
op = (struct ospf_packet *) pkt;
/* Now fill ospf_hello header */
ospf_pkt_fill_hdr(ifa, pkt, HELLO_P);
#ifdef OSPFv2
pkt->netmask = ipa_mkmask(ifa->iface->addr->pxlen);
ipa_hton(pkt->netmask);
if ((ifa->type == OSPF_IT_VLINK) || (ifa->type == OSPF_IT_PTP))
pkt->netmask = IPA_NONE;
#endif
pkt->helloint = ntohs(ifa->helloint);
pkt->priority = ifa->priority;
#ifdef OSPFv3
pkt->iface_id = htonl(ifa->iface->index);
pkt->options3 = ifa->oa->options >> 16;
pkt->options2 = ifa->oa->options >> 8;
#endif
pkt->options = ifa->oa->options;
#ifdef OSPFv2
pkt->deadint = htonl(ifa->dead);
pkt->dr = htonl(ipa_to_u32(ifa->drip));
pkt->bdr = htonl(ipa_to_u32(ifa->bdrip));
#else /* OSPFv3 */
pkt->deadint = htons(ifa->dead);
pkt->dr = htonl(ifa->drid);
pkt->bdr = htonl(ifa->bdrid);
#endif
/* Fill all neighbors */
i = 0;
pp = (u32 *) (((u8 *) pkt) + sizeof(struct ospf_hello_packet));
WALK_LIST(neigh, ifa->neigh_list)
{
if ((i+1) * sizeof(u32) + sizeof(struct ospf_hello_packet) > ospf_pkt_maxsize(ifa))
{
OSPF_TRACE(D_PACKETS, "Too many neighbors on the interface!");
break;
}
*(pp + i) = htonl(neigh->rid);
i++;
}
length = sizeof(struct ospf_hello_packet) + i * sizeof(u32);
op->length = htons(length);
switch(ifa->type)
{
case OSPF_IT_NBMA:
if (timer == NULL) /* Response to received hello */
{
ospf_send_to(ifa, dirn->ip);
}
else
{
int toall = 0;
int meeli = 0;
if (ifa->state > OSPF_IS_DROTHER)
toall = 1;
if (ifa->priority > 0)
meeli = 1;
WALK_LIST(nb, ifa->nbma_list)
{
send = 1;
WALK_LIST(n1, ifa->neigh_list)
{
if (ipa_equal(nb->ip, n1->ip))
{
send = 0;
break;
}
}
if ((poll == 1) && (send))
{
if (toall || (meeli && nb->eligible))
ospf_send_to(ifa, nb->ip);
}
}
if (poll == 0)
{
WALK_LIST(n1, ifa->neigh_list)
{
if (toall || (n1->rid == ifa->drid) || (n1->rid == ifa->bdrid) ||
(meeli && (n1->priority > 0)))
ospf_send_to(ifa, n1->ip);
}
}
}
break;
case OSPF_IT_VLINK:
ospf_send_to(ifa, ifa->vip);
break;
default:
ospf_send_to(ifa, AllSPFRouters);
}
OSPF_TRACE(D_PACKETS, "HELLO packet sent via %s%s",
(ifa->type == OSPF_IT_VLINK ? "vlink-" : ""), ifa->iface->name);
}
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