bird/proto/ospf/hello.c

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/*
* BIRD -- OSPF
*
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* (c) 1999--2004 Ondrej Filip <feela@network.cz>
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* (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org>
* (c) 2009--2014 CZ.NIC z.s.p.o.
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "ospf.h"
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struct ospf_hello2_packet
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{
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struct ospf_packet hdr;
union ospf_auth auth;
u32 netmask;
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u16 helloint;
u8 options;
u8 priority;
u32 deadint;
u32 dr;
u32 bdr;
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u32 neighbors[];
};
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struct ospf_hello3_packet
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{
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struct ospf_packet hdr;
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u32 iface_id;
u32 options;
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u16 helloint;
u16 deadint;
u32 dr;
u32 bdr;
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u32 neighbors[];
};
void
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ospf_send_hello(struct ospf_iface *ifa, int kind, struct ospf_neighbor *dirn)
{
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struct ospf_proto *p = ifa->oa->po;
struct ospf_packet *pkt;
struct ospf_neighbor *neigh, *n1;
struct nbma_node *nb;
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u32 *neighbors;
uint length;
int i, max;
if (ifa->state <= OSPF_IS_LOOP)
return;
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if (ifa->stub)
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return;
pkt = ospf_tx_buffer(ifa);
ospf_pkt_fill_hdr(ifa, pkt, HELLO_P);
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if (ospf_is_v2(p))
{
struct ospf_hello2_packet *ps = (void *) pkt;
if ((ifa->type == OSPF_IT_VLINK) ||
((ifa->type == OSPF_IT_PTP) && !ifa->ptp_netmask))
ps->netmask = 0;
else
ps->netmask = htonl(u32_mkmask(ifa->addr->prefix.pxlen));
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ps->helloint = ntohs(ifa->helloint);
ps->options = ifa->oa->options;
ps->priority = ifa->priority;
ps->deadint = htonl(ifa->deadint);
ps->dr = htonl(ipa_to_u32(ifa->drip));
ps->bdr = htonl(ipa_to_u32(ifa->bdrip));
length = sizeof(struct ospf_hello2_packet);
neighbors = ps->neighbors;
}
else
{
struct ospf_hello3_packet *ps = (void *) pkt;
ps->iface_id = htonl(ifa->iface_id);
ps->options = ntohl(ifa->oa->options | (ifa->priority << 24));
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ps->helloint = ntohs(ifa->helloint);
ps->deadint = htons(ifa->deadint);
ps->dr = htonl(ifa->drid);
ps->bdr = htonl(ifa->bdrid);
length = sizeof(struct ospf_hello3_packet);
neighbors = ps->neighbors;
}
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i = 0;
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max = (ospf_pkt_maxsize(ifa) - length) / sizeof(u32);
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/* Fill all neighbors */
if (kind != OHS_SHUTDOWN)
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{
WALK_LIST(neigh, ifa->neigh_list)
{
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if (i == max)
{
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log(L_WARN "%s: Too many neighbors on %s", p->p.name, ifa->ifname);
break;
}
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neighbors[i] = htonl(neigh->rid);
i++;
}
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}
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length += i * sizeof(u32);
pkt->length = htons(length);
OSPF_TRACE(D_PACKETS, "HELLO packet sent via %s", ifa->ifname);
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switch(ifa->type)
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{
case OSPF_IT_BCAST:
case OSPF_IT_PTP:
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ospf_send_to_all(ifa);
break;
case OSPF_IT_NBMA:
if (dirn) /* Response to received hello */
{
ospf_send_to(ifa, dirn->ip);
break;
}
int to_all = ifa->state > OSPF_IS_DROTHER;
int me_elig = ifa->priority > 0;
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if (kind == OHS_POLL) /* Poll timer */
{
WALK_LIST(nb, ifa->nbma_list)
if (!nb->found && (to_all || (me_elig && nb->eligible)))
ospf_send_to(ifa, nb->ip);
}
else /* Hello timer */
{
WALK_LIST(n1, ifa->neigh_list)
if (to_all || (me_elig && (n1->priority > 0)) ||
(n1->rid == ifa->drid) || (n1->rid == ifa->bdrid))
ospf_send_to(ifa, n1->ip);
}
break;
case OSPF_IT_PTMP:
WALK_LIST(n1, ifa->neigh_list)
ospf_send_to(ifa, n1->ip);
WALK_LIST(nb, ifa->nbma_list)
if (!nb->found)
ospf_send_to(ifa, nb->ip);
/* If there is no other target, we also send HELLO packet to the other end */
if (ipa_nonzero(ifa->addr->opposite) && !ifa->strictnbma &&
EMPTY_LIST(ifa->neigh_list) && EMPTY_LIST(ifa->nbma_list))
ospf_send_to(ifa, ifa->addr->opposite);
break;
case OSPF_IT_VLINK:
ospf_send_to(ifa, ifa->vip);
break;
default:
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bug("Bug in ospf_send_hello()");
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}
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}
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void
ospf_receive_hello(struct ospf_packet *pkt, struct ospf_iface *ifa,
struct ospf_neighbor *n, ip_addr faddr)
{
struct ospf_proto *p = ifa->oa->po;
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const char *err_dsc = NULL;
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u32 rcv_iface_id, rcv_helloint, rcv_deadint, rcv_dr, rcv_bdr;
uint rcv_options, rcv_priority;
uint loc_options = ifa->oa->options;
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u32 *neighbors;
u32 neigh_count;
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uint plen, i, err_val = 0;
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/* RFC 2328 10.5 */
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/*
* We may not yet have the associate neighbor, so we use Router ID from the
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* packet instead of one from the neighbor structure for log messages.
*/
u32 rcv_rid = ntohl(pkt->routerid);
OSPF_TRACE(D_PACKETS, "HELLO packet received from nbr %R on %s", rcv_rid, ifa->ifname);
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plen = ntohs(pkt->length);
if (ospf_is_v2(p))
{
struct ospf_hello2_packet *ps = (void *) pkt;
if (plen < sizeof(struct ospf_hello2_packet))
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DROP("too short", plen);
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rcv_iface_id = 0;
rcv_helloint = ntohs(ps->helloint);
rcv_deadint = ntohl(ps->deadint);
rcv_dr = ntohl(ps->dr);
rcv_bdr = ntohl(ps->bdr);
rcv_options = ps->options;
rcv_priority = ps->priority;
int pxlen = u32_masklen(ntohl(ps->netmask));
if (pxlen < 0)
DROP("prefix garbled", ntohl(ps->netmask));
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if ((ifa->type != OSPF_IT_VLINK) &&
(ifa->type != OSPF_IT_PTP) &&
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((uint) pxlen != ifa->addr->prefix.pxlen))
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DROP("prefix length mismatch", pxlen);
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neighbors = ps->neighbors;
neigh_count = (plen - sizeof(struct ospf_hello2_packet)) / sizeof(u32);
}
else /* OSPFv3 */
{
struct ospf_hello3_packet *ps = (void *) pkt;
if (plen < sizeof(struct ospf_hello3_packet))
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DROP("too short", plen);
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rcv_iface_id = ntohl(ps->iface_id);
rcv_helloint = ntohs(ps->helloint);
rcv_deadint = ntohs(ps->deadint);
rcv_dr = ntohl(ps->dr);
rcv_bdr = ntohl(ps->bdr);
rcv_options = ntohl(ps->options) & 0x00FFFFFF;
rcv_priority = ntohl(ps->options) >> 24;
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neighbors = ps->neighbors;
neigh_count = (plen - sizeof(struct ospf_hello3_packet)) / sizeof(u32);
}
if (rcv_helloint != ifa->helloint)
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DROP("hello interval mismatch", rcv_helloint);
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if (rcv_deadint != ifa->deadint)
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DROP("dead interval mismatch", rcv_deadint);
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/* Check whether bits E, N match */
if ((rcv_options ^ loc_options) & (OPT_E | OPT_N))
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DROP("area type mismatch", rcv_options);
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/* RFC 5838 2.4 - AF-bit check unless on IPv6 unicast */
if ((loc_options & OPT_AF) && !(loc_options & OPT_V6) && !(rcv_options & OPT_AF))
DROP("AF-bit mismatch", rcv_options);
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/* Check consistency of existing neighbor entry */
if (n)
{
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uint t = ifa->type;
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if (ospf_is_v2(p) && ((t == OSPF_IT_BCAST) || (t == OSPF_IT_NBMA) || (t == OSPF_IT_PTMP)))
{
/* Neighbor identified by IP address; Router ID may change */
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if (n->rid != rcv_rid)
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{
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OSPF_TRACE(D_EVENTS, "Neighbor %R on %s changed Router ID to %R",
n->rid, ifa->ifname, rcv_rid);
ospf_neigh_sm(n, INM_KILLNBR);
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n = NULL;
}
}
else /* OSPFv3 or OSPFv2/PtP */
{
/* Neighbor identified by Router ID; IP address may change */
if (!ipa_equal(faddr, n->ip))
{
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OSPF_TRACE(D_EVENTS, "Neighbor %R on %s changed IP address to %I",
n->rid, ifa->ifname, n->ip, faddr);
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n->ip = faddr;
}
}
}
if (!n)
{
if ((ifa->type == OSPF_IT_NBMA) || (ifa->type == OSPF_IT_PTMP))
{
struct nbma_node *nn = find_nbma_node(ifa, faddr);
if (!nn && ifa->strictnbma)
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DROP1("new neighbor denied");
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if (nn && (ifa->type == OSPF_IT_NBMA) &&
(((rcv_priority == 0) && nn->eligible) ||
((rcv_priority > 0) && !nn->eligible)))
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DROP("eligibility mismatch", rcv_priority);
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if (nn)
nn->found = 1;
}
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OSPF_TRACE(D_EVENTS, "New neighbor %R on %s, IP address %I",
rcv_rid, ifa->ifname, faddr);
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n = ospf_neighbor_new(ifa);
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n->rid = rcv_rid;
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n->ip = faddr;
n->dr = rcv_dr;
n->bdr = rcv_bdr;
n->priority = rcv_priority;
n->iface_id = rcv_iface_id;
if (n->ifa->cf->bfd)
ospf_neigh_update_bfd(n, n->ifa->bfd);
}
u32 n_id = ospf_is_v2(p) ? ipa_to_u32(n->ip) : n->rid;
u32 old_dr = n->dr;
u32 old_bdr = n->bdr;
u32 old_priority = n->priority;
u32 old_iface_id = n->iface_id;
n->dr = rcv_dr;
n->bdr = rcv_bdr;
n->priority = rcv_priority;
n->iface_id = rcv_iface_id;
/* Update inactivity timer */
ospf_neigh_sm(n, INM_HELLOREC);
/* RFC 2328 9.5.1 - non-eligible routers reply to hello on NBMA nets */
if (ifa->type == OSPF_IT_NBMA)
if ((ifa->priority == 0) && (n->priority > 0))
ospf_send_hello(n->ifa, OHS_HELLO, n);
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/* Examine list of neighbors */
for (i = 0; i < neigh_count; i++)
if (neighbors[i] == htonl(p->router_id))
goto found_self;
ospf_neigh_sm(n, INM_1WAYREC);
return;
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found_self:
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ospf_neigh_sm(n, INM_2WAYREC);
if (n->iface_id != old_iface_id)
{
/* If neighbor is DR, also update cached DR interface ID */
if (ifa->drid == n->rid)
ifa->dr_iface_id = n->iface_id;
/* RFC 5340 4.4.3 Event 4 - change of neighbor's interface ID */
ospf_notify_rt_lsa(ifa->oa);
/* Missed in RFC 5340 4.4.3 Event 4 - (Px-)Net-LSA uses iface_id to ref Link-LSAs */
ospf_notify_net_lsa(ifa);
}
if (ifa->state == OSPF_IS_WAITING)
{
/* Neighbor is declaring itself DR (and there is no BDR) or as BDR */
if (((n->dr == n_id) && (n->bdr == 0)) || (n->bdr == n_id))
ospf_iface_sm(ifa, ISM_BACKS);
}
else if (ifa->state >= OSPF_IS_DROTHER)
{
/* Neighbor changed priority or started/stopped declaring itself as DR/BDR */
if ((n->priority != old_priority) ||
((n->dr == n_id) && (old_dr != n_id)) ||
((n->dr != n_id) && (old_dr == n_id)) ||
((n->bdr == n_id) && (old_bdr != n_id)) ||
((n->bdr != n_id) && (old_bdr == n_id)))
ospf_iface_sm(ifa, ISM_NEICH);
}
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return;
drop:
LOG_PKT("Bad HELLO packet from nbr %R on %s - %s (%u)",
rcv_rid, ifa->ifname, err_dsc, err_val);
}