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BIRD Internet Routing Daemon
Commit a7a7372a authored by Ondřej Zajíček's avatar Ondřej Zajíček
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Temporary integrated OSPF commit.

parent 70945cb6
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Showing with 781 additions and 693 deletions
nest/locks.c
View file @ a7a7372a
......@@ -22,10 +22,11 @@
* or some other non-shareable resource, it asks the core to lock it and it doesn't
* use the resource until it's notified that it has acquired the lock.
*
* Object locks are represented by &object_lock structures which are in turn a kind of
* resource. Lockable resources are uniquely determined by resource type
* Object locks are represented by &object_lock structures which are in turn a
* kind of resource. Lockable resources are uniquely determined by resource type
* (%OBJLOCK_UDP for a UDP port etc.), IP address (usually a broadcast or
* multicast address the port is bound to), port number and interface.
* multicast address the port is bound to), port number, interface and optional
* instance ID.
*/
#undef LOCAL_DEBUG
......@@ -45,6 +46,7 @@ olock_same(struct object_lock *x, struct object_lock *y)
x->type == y->type &&
x->iface == y->iface &&
x->port == y->port &&
x->inst == y->inst &&
ipa_equal(x->addr, y->addr);
}
......@@ -88,7 +90,7 @@ olock_dump(resource *r)
struct object_lock *l = (struct object_lock *) r;
static char *olock_states[] = { "free", "locked", "waiting", "event" };
debug("(%d:%s:%I:%d) [%s]\n", l->type, (l->iface ? l->iface->name : "?"), l->addr, l->port, olock_states[l->state]);
debug("(%d:%s:%I:%d:%d) [%s]\n", l->type, (l->iface ? l->iface->name : "?"), l->addr, l->port, l->inst, olock_states[l->state]);
if (!EMPTY_LIST(l->waiters))
debug(" [wanted]\n");
}
......
nest/locks.h
View file @ a7a7372a
......@@ -26,9 +26,10 @@
struct object_lock {
resource r;
ip_addr addr; /* Identification of a object: IP address */
unsigned int type; /* ... object type (OBJLOCK_xxx) */
uint type; /* ... object type (OBJLOCK_xxx) */
uint port; /* ... port number */
uint inst; /* ... instance ID */
struct iface *iface; /* ... interface */
unsigned int port; /* ... port number */
void (*hook)(struct object_lock *); /* Called when the lock succeeds */
void *data; /* User data */
/* ... internal to lock manager, don't touch ... */
......
proto/ospf/dbdes.c
View file @ a7a7372a
......@@ -200,15 +200,11 @@ ospf_do_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)
* of the buffer.
*/
void
ospf_send_dbdes(struct ospf_neighbor *n, int next)
ospf_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n, int next)
{
struct ospf_iface *ifa = n->ifa;
struct ospf_area *oa = ifa->oa;
struct ospf_proto *p = oa->po;
/* RFC 2328 10.8 */
if (oa->rt == NULL)
if (n->ifa->oa->rt == NULL)
return;
switch (n->state)
......@@ -312,6 +308,7 @@ ospf_process_dbdes(struct ospf_proto *p, struct ospf_packet *pkt, struct ospf_ne
s_add_tail(&n->lsrql, SNODE req);
req->lsa = lsa;
req->lsa_body = LSA_BODY_DUMMY;
}
}
......@@ -394,7 +391,7 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
n->imms = rcv_imms;
OSPF_TRACE(D_PACKETS, "I'm slave to %I", n->ip);
ospf_neigh_sm(n, INM_NEGDONE);
ospf_send_dbdes(n, 1);
ospf_send_dbdes(p, n, 1);
break;
}
......@@ -426,7 +423,7 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
if (!(n->myimms & DBDES_MS))
{
/* Slave should retransmit dbdes packet */
ospf_send_dbdes(n, 0);
ospf_send_dbdes(p, n, 0);
}
return;
}
......@@ -472,7 +469,7 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))
ospf_neigh_sm(n, INM_EXDONE);
else
ospf_send_dbdes(n, 1);
ospf_send_dbdes(p, n, 1);
}
else
{
......@@ -489,7 +486,7 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
if (ospf_process_dbdes(p, pkt, n) < 0)
return;
ospf_send_dbdes(n, 1);
ospf_send_dbdes(p, n, 1);
}
break;
......@@ -504,7 +501,7 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
if (!(n->myimms & DBDES_MS))
{
/* Slave should retransmit dbdes packet */
ospf_send_dbdes(n, 0);
ospf_send_dbdes(p, n, 0);
}
return;
}
......
proto/ospf/hello.c
View file @ a7a7372a
......@@ -275,7 +275,7 @@ ospf_receive_hello(struct ospf_packet *pkt, struct ospf_iface *ifa,
/* Check consistency of existing neighbor entry */
if (n)
{
unsigned t = ifa->type;
uint t = ifa->type;
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 */
......
proto/ospf/iface.c
View file @ a7a7372a
......@@ -620,18 +620,11 @@ ospf_iface_new(struct ospf_area *oa, struct ifa *addr, struct ospf_iface_patt *i
add_tail(&oa->po->iface_list, NODE ifa);
/*
* In some cases we allow more ospf_ifaces on one physical iface.
* In OSPFv2, if they use different IP address prefix.
* In OSPFv3, if they use different instance_id.
* Therefore, we store such info to lock->addr field.
*/
// XXXX review
struct object_lock *lock = olock_new(pool);
lock->addr = ospf_is_v2(p) ? ifa->addr->prefix : _MI6(0,0,0,ifa->instance_id);
lock->addr = ospf_is_v2(p) ? ifa->addr->prefix : IPA_NONE;
lock->type = OBJLOCK_IP;
lock->port = OSPF_PROTO;
lock->inst = ifa->instance_id;
lock->iface = iface;
lock->data = ifa;
lock->hook = ospf_iface_add;
......@@ -997,7 +990,7 @@ ospf_walk_matching_iface_patts(struct ospf_proto *p, struct ospf_mip_walk *s)
BIT32_SET(s->ignore, id);
/* If we already found it in previous areas, ignore it and add warning */
if (!BIT32_TEST(s->active, id))
if (BIT32_TEST(s->active, id))
{ s->warn = 1; continue; }
BIT32_SET(s->active, id);
......@@ -1046,7 +1039,7 @@ ospf_ifa_notify2(struct proto *P, uint flags, struct ifa *a)
{
struct ospf_mip_walk s = { .iface = a->iface, .a = a };
while (ospf_walk_matching_iface_patts(p, &s))
ospf_iface_new(s.oa, s.a, s.ip);
ospf_iface_new(s.oa, a, s.ip);
}
if (flags & IF_CHANGE_DOWN)
......@@ -1078,7 +1071,7 @@ ospf_ifa_notify3(struct proto *P, uint flags, struct ifa *a)
{
struct ospf_mip_walk s = { .iface = a->iface };
while (ospf_walk_matching_iface_patts(p, &s))
ospf_iface_new(s.oa, s.a, s.ip);
ospf_iface_new(s.oa, a, s.ip);
}
if (flags & IF_CHANGE_DOWN)
......
proto/ospf/lsack.c
View file @ a7a7372a
......@@ -79,10 +79,9 @@ ospf_reset_lsack_queue(struct ospf_neighbor *n)
}
static inline void
ospf_send_lsack(struct ospf_neighbor *n, int queue)
ospf_send_lsack_(struct ospf_proto *p, struct ospf_neighbor *n, int queue)
{
struct ospf_iface *ifa = n->ifa;
struct ospf_proto *p = ifa->oa->po;
struct ospf_lsa_header *lsas;
struct ospf_packet *pkt;
struct lsa_node *no;
......@@ -121,10 +120,10 @@ ospf_send_lsack(struct ospf_neighbor *n, int queue)
}
void
ospf_lsack_send(struct ospf_neighbor *n, int queue)
ospf_send_lsack(struct ospf_proto *p, struct ospf_neighbor *n, int queue)
{
while (!EMPTY_LIST(n->ackl[queue]))
ospf_send_lsack(n, queue);
ospf_send_lsack_(p, n, queue);
}
void
......@@ -160,9 +159,6 @@ ospf_receive_lsack(struct ospf_packet *pkt, struct ospf_iface *ifa,
if (lsa_comp(&lsa, &ret->lsa) != CMP_SAME)
{
if ((lsa.sn == LSA_MAXSEQNO) && (lsa.age == LSA_MAXAGE))
continue;
OSPF_TRACE(D_PACKETS, "Strange LSACK from %I", n->ip);
OSPF_TRACE(D_PACKETS, "Type: %04x, Id: %R, Rt: %R",
lsa_type, lsa.id, lsa.rt);
......
proto/ospf/lsreq.c
View file @ a7a7372a
......@@ -71,7 +71,8 @@ ospf_send_lsreq(struct ospf_proto *p, struct ospf_neighbor *n)
ospf_pkt_fill_hdr(ifa, pkt, LSREQ_P);
ospf_lsreq_body(p, pkt, &lsrs, &lsr_max);
// for (i = 0; i < lsr_max; i++)
/* We send smaller LSREQ to prevent multiple LSACKs as answer */
lsr_max = lsr_max / 4;
i = 0;
WALK_SLIST(en, n->lsrql)
......
proto/ospf/lsupd.c
View file @ a7a7372a
......@@ -115,7 +115,8 @@ ospf_lsa_lsrt_up(struct top_hash_entry *en, struct ospf_neighbor *n)
s_add_tail(&n->lsrtl, SNODE ret);
}
memcpy(&ret->lsa, &en->lsa, sizeof(struct ospf_lsa_header));
ret->lsa = en->lsa;
ret->lsa_body = LSA_BODY_DUMMY;
}
static inline int
......@@ -134,25 +135,37 @@ ospf_lsa_lsrt_down(struct top_hash_entry *en, struct ospf_neighbor *n)
return 0;
}
void
ospf_add_flushed_to_lsrt(struct ospf_proto *p, struct ospf_neighbor *n)
{
struct top_hash_entry *en;
WALK_SLIST(en, p->lsal)
if ((en->lsa.age == LSA_MAXAGE) && (en->lsa_body != NULL) &&
lsa_flooding_allowed(en->lsa_type, en->domain, n->ifa))
ospf_lsa_lsrt_up(en, n);
}
static void ospf_lsupd_flood_ifa(struct ospf_proto *p, struct ospf_iface *ifa, struct top_hash_entry *en);
static void ospf_send_lsupd_to_ifa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_iface *ifa);
/**
* ospf_lsupd_flood - send received or generated LSA to the neighbors
* @p: OSPF protocol
* ospf_flood_lsa - send LSA to the neighbors
* @p: OSPF protocol instance
* @en: LSA entry
* @from: neighbor than sent this LSA (or NULL if LSA is local)
*
* return value - was the LSA flooded back?
*/
int
ospf_lsupd_flood(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_neighbor *from)
ospf_flood_lsa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_neighbor *from)
{
struct ospf_iface *ifa;
struct ospf_neighbor *n;
/* RFC 2328 13.3 */
int back = 0;
WALK_LIST(ifa, p->iface_list)
{
......@@ -185,6 +198,8 @@ ospf_lsupd_flood(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_ne
{
s_rem_node(SNODE req);
ospf_hash_delete(n->lsrqh, req);
n->want_lsreq = 1;
if ((EMPTY_SLIST(n->lsrql)) && (n->state == NEIGHBOR_LOADING))
ospf_neigh_sm(n, INM_LOADDONE);
}
......@@ -227,7 +242,7 @@ ospf_lsupd_flood(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_ne
}
/* 13.3 (5) - finally flood the packet */
ospf_lsupd_flood_ifa(p, ifa, en);
ospf_send_lsupd_to_ifa(p, en, ifa);
}
return back;
......@@ -288,7 +303,7 @@ ospf_prepare_lsupd(struct ospf_proto *p, struct ospf_iface *ifa,
static void
ospf_lsupd_flood_ifa(struct ospf_proto *p, struct ospf_iface *ifa, struct top_hash_entry *en)
ospf_send_lsupd_to_ifa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_iface *ifa)
{
uint c = ospf_prepare_lsupd(p, ifa, &en, 1);
......@@ -384,7 +399,8 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
/* RFC 2328 13. */
int sendreq = 1; /* XXXX: review sendreq */
int skip_lsreq = 0;
n->want_lsreq = 0;
uint plen = ntohs(pkt->length);
if (plen < (ospf_lsupd_hdrlen(p) + sizeof(struct ospf_lsa_header)))
......@@ -436,7 +452,7 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
u16 chsum = lsa_n->checksum;
if (chsum != lsasum_check(lsa_n, NULL))
{
log(L_WARN "%s: Received LSA from %I with bad checskum: %x %x",
log(L_WARN "%s: Received LSA from %I with bad checksum: %x %x",
p->p.name, n->ip, chsum, lsa_n->checksum);
continue;
}
......@@ -501,7 +517,7 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
if (en && ((now - en->inst_time) < MINLSARRIVAL))
{
OSPF_TRACE(D_EVENTS, "Skipping LSA received in less that MinLSArrival");
sendreq = 0;
skip_lsreq = 1;
continue;
}
......@@ -514,7 +530,6 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
{
log(L_WARN "%s: Received invalid LSA from %I", p->p.name, n->ip);
mb_free(body);
sendreq = 0;
continue;
}
......@@ -528,22 +543,27 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
}
/* 13. (5c) - remove old LSA from all retransmission lists */
/* Must be done before (5b), otherwise it also removes the new entries from (5b) */
/*
* We only need to remove it from the retransmission list of the neighbor
* that send us the new LSA. The old LSA is automatically replaced in
* retransmission lists by the new LSA.
*/
if (en)
ospf_lsa_lsrt_down(en, n);
#if 0
/*
{
struct ospf_iface *ifi;
struct ospf_neighbor *ni;
WALK_LIST(ifi, p->iface_list)
WALK_LIST(ni, ifi->neigh_list)
if (ni->state > NEIGHBOR_EXSTART)
ospf_lsa_lsrt_down(en, ni);
}
*/
* Old code for removing LSA from all retransmission lists. Must be done
* before (5b), otherwise it also removes the new entries from (5b).
*/
struct ospf_iface *ifi;
struct ospf_neighbor *ni;
WALK_LIST(ifi, p->iface_list)
WALK_LIST(ni, ifi->neigh_list)
if (ni->state > NEIGHBOR_EXSTART)
ospf_lsa_lsrt_down(en, ni);
#endif
/* 13. (5d) - install new LSA into database */
en = ospf_install_lsa(p, &lsa, lsa_type, lsa_domain, body);
......@@ -553,7 +573,7 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
ospf_notify_net_lsa(ifa);
/* 13. (5b) - flood new LSA */
int flood_back = ospf_lsupd_flood(p, en, n);
int flood_back = ospf_flood_lsa(p, en, n);
/* 13.5. - schedule ACKs (tbl 19, cases 1+2) */
if (! flood_back)
......@@ -582,7 +602,7 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
else
ospf_enqueue_lsack(n, lsa_n, ACKL_DIRECT);
sendreq = 0;
skip_lsreq = 1;
continue;
}
......@@ -598,11 +618,17 @@ ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
}
}
/* Send direct LSAs */
ospf_lsack_send(n, ACKL_DIRECT);
/* If loading, ask for another part of neighbor's database */
if (sendreq && (n->state == NEIGHBOR_LOADING))
/* Send direct LSACKs */
ospf_send_lsack(p, n, ACKL_DIRECT);
/*
* In loading state, we should ask for another batch of LSAs. This is only
* vaguely mentioned in RFC 2328. We send a new LSREQ only if the current
* LSUPD actually removed some entries from LSA request list (want_lsreq) and
* did not contain duplicate or early LSAs (skip_lsreq). The first condition
* prevents endless floods, the second condition helps with flow control.
*/
if ((n->state == NEIGHBOR_LOADING) && n->want_lsreq && !skip_lsreq)
ospf_send_lsreq(p, n);
}
proto/ospf/neighbor.c
View file @ a7a7372a
......@@ -33,13 +33,26 @@ static void rxmt_timer_hook(timer * timer);
static void ackd_timer_hook(timer * t);
static void
init_lists(struct ospf_neighbor *n)
init_lists(struct ospf_proto *p, struct ospf_neighbor *n)
{
s_init_list(&(n->lsrql));
n->lsrqh = ospf_top_new(n->pool);
n->lsrqh = ospf_top_new(p, n->pool);
s_init_list(&(n->lsrtl));
n->lsrth = ospf_top_new(n->pool);
n->lsrth = ospf_top_new(p, n->pool);
}
static void
release_lsrtl(struct ospf_proto *p, struct ospf_neighbor *n)
{
struct top_hash_entry *ret, *en;
WALK_SLIST(ret, n->lsrtl)
{
en = ospf_hash_find_entry(p->gr, ret);
if (en)
en->ret_count--;
}
}
/* Resets LSA request and retransmit lists.
......@@ -47,11 +60,12 @@ init_lists(struct ospf_neighbor *n)
* it is reset during entering EXCHANGE state.
*/
static void
reset_lists(struct ospf_neighbor *n)
reset_lists(struct ospf_proto *p, struct ospf_neighbor *n)
{
release_lsrtl(p,n);
ospf_top_free(n->lsrqh);
ospf_top_free(n->lsrth);
init_lists(n);
init_lists(p, n);
}
struct ospf_neighbor *
......@@ -68,7 +82,7 @@ ospf_neighbor_new(struct ospf_iface *ifa)
n->csn = 0;
n->state = NEIGHBOR_DOWN;
init_lists(n);
init_lists(p, n);
s_init(&(n->dbsi), &(p->lsal));
n->inactim = tm_new(pool);
......@@ -360,6 +374,10 @@ ospf_neigh_sm(struct ospf_neighbor *n, int event)
s_get(&(n->dbsi));
s_init(&(n->dbsi), &p->lsal);
/* Add MaxAge LSA entries to retransmission list */
ospf_add_flushed_to_lsrt(p, n);
/* FIXME: Why is this here ? */
ospf_reset_lsack_queue(n);
}
else
......@@ -388,7 +406,7 @@ ospf_neigh_sm(struct ospf_neighbor *n, int event)
if (n->state >= NEIGHBOR_EXSTART)
if (!can_do_adj(n))
{
reset_lists(n);
reset_lists(p,n);
neigh_chstate(n, NEIGHBOR_2WAY);
}
break;
......@@ -399,7 +417,7 @@ ospf_neigh_sm(struct ospf_neighbor *n, int event)
case INM_BADLSREQ:
if (n->state >= NEIGHBOR_EXCHANGE)
{
reset_lists(n);
reset_lists(p, n);
neigh_chstate(n, NEIGHBOR_EXSTART);
}
break;
......@@ -407,12 +425,12 @@ ospf_neigh_sm(struct ospf_neighbor *n, int event)
case INM_KILLNBR:
case INM_LLDOWN:
case INM_INACTTIM:
reset_lists(n);
reset_lists(p, n);
neigh_chstate(n, NEIGHBOR_DOWN);
break;
case INM_1WAYREC:
reset_lists(n);
reset_lists(p, n);
neigh_chstate(n, NEIGHBOR_INIT);
break;
......@@ -552,8 +570,10 @@ ospf_neigh_remove(struct ospf_neighbor *n)
nn->found = 0;
}
s_get(&(n->dbsi));
neigh_chstate(n, NEIGHBOR_DOWN);
s_get(&(n->dbsi));
release_lsrtl(p, n);
rem_node(NODE n);
rfree(n->pool);
OSPF_TRACE(D_EVENTS, "Deleting neigbor %R", n->rid);
......@@ -620,9 +640,9 @@ ospf_sh_neigh_info(struct ospf_neighbor *n)
}
static void
rxmt_timer_hook(timer * timer)
rxmt_timer_hook(timer *t)
{
struct ospf_neighbor *n = (struct ospf_neighbor *) timer->data;
struct ospf_neighbor *n = t->data;
struct ospf_proto *p = n->ifa->oa->po;
DBG("%s: RXMT timer fired on interface %s for neigh %I\n",
......@@ -631,12 +651,12 @@ rxmt_timer_hook(timer * timer)
switch (n->state)
{
case NEIGHBOR_EXSTART:
ospf_send_dbdes(n, 1);
ospf_send_dbdes(p, n, 1);
return;
case NEIGHBOR_EXCHANGE:
if (n->myimms & DBDES_MS)
ospf_send_dbdes(n, 0);
ospf_send_dbdes(p, n, 0);
case NEIGHBOR_LOADING:
ospf_send_lsreq(p, n);
return;
......@@ -653,8 +673,13 @@ rxmt_timer_hook(timer * timer)
}
static void
ackd_timer_hook(timer * t)
ackd_timer_hook(timer *t)
{
struct ospf_neighbor *n = t->data;
ospf_lsack_send(n, ACKL_DELAY);
struct ospf_proto *p = n->ifa->oa->po;
DBG("%s: ACKD timer fired on interface %s for neigh %I\n",
p->p.name, n->ifa->ifname, n->ip);
ospf_send_lsack(p, n, ACKL_DELAY);
}
proto/ospf/ospf.c
View file @ a7a7372a
......@@ -11,93 +11,81 @@
/**
* DOC: Open Shortest Path First (OSPF)
*
* The OSPF protocol is quite complicated and its complex implemenation is
* split to many files. In |ospf.c|, you will find mainly the interface
* for communication with the core (e.g., reconfiguration hooks, shutdown
* and initialisation and so on). In |packet.c|, you will find various
* functions for sending and receiving generic OSPF packets. There are
* also routines for authentication and checksumming. File |iface.c| contains
* the interface state machine and functions for allocation and deallocation of OSPF's
* interface data structures. Source |neighbor.c| includes the neighbor state
* machine and functions for election of Designated Router and Backup
* Designated router. In |hello.c|, there are routines for sending
* and receiving of hello packets as well as functions for maintaining
* wait times and the inactivity timer. Files |lsreq.c|, |lsack.c|, |dbdes.c|
* contain functions for sending and receiving of link-state requests,
* link-state acknowledgements and database descriptions respectively.
* In |lsupd.c|, there are functions for sending and receiving
* of link-state updates and also the flooding algorithm. Source |topology.c| is
* a place where routines for searching LSAs in the link-state database,
* adding and deleting them reside, there also are functions for originating
* of various types of LSAs (router LSA, net LSA, external LSA). File |rt.c|
* contains routines for calculating the routing table. |lsalib.c| is a set
* of various functions for working with the LSAs (endianity conversions,
* calculation of checksum etc.).
* The OSPF protocol is quite complicated and its complex implemenation is split
* to many files. In |ospf.c|, you will find mainly the interface for
* communication with the core (e.g., reconfiguration hooks, shutdown and
* initialisation and so on). File |iface.c| contains the interface state
* machine and functions for allocation and deallocation of OSPF's interface
* data structures. Source |neighbor.c| includes the neighbor state machine and
* functions for election of Designated Router and Backup Designated router. In
* |packet.c|, you will find various functions for sending and receiving generic
* OSPF packets. There are also routines for authentication and checksumming.
* In |hello.c|, there are routines for sending and receiving of hello packets
* as well as functions for maintaining wait times and the inactivity timer.
* Files |lsreq.c|, |lsack.c|, |dbdes.c| contain functions for sending and
* receiving of link-state requests, link-state acknowledgements and database
* descriptions respectively. In |lsupd.c|, there are functions for sending and
* receiving of link-state updates and also the flooding algorithm. Source
* |topology.c| is a place where routines for searching LSAs in the link-state
* database, adding and deleting them reside, there also are functions for
* originating of various types of LSAs (router LSA, net LSA, external LSA).
* File |rt.c| contains routines for calculating the routing table. |lsalib.c|
* is a set of various functions for working with the LSAs (endianity
* conversions, calculation of checksum etc.).
*
* One instance of the protocol is able to hold LSA databases for
* multiple OSPF areas, to exchange routing information between
* multiple neighbors and to calculate the routing tables. The core
* structure is &ospf_proto to which multiple &ospf_area and
* &ospf_iface structures are connected. &ospf_area is also connected to
* &top_hash_graph which is a dynamic hashing structure that
* describes the link-state database. It allows fast search, addition
* and deletion. Each LSA is kept in two pieces: header and body. Both of them are
* One instance of the protocol is able to hold LSA databases for multiple OSPF
* areas, to exchange routing information between multiple neighbors and to
* calculate the routing tables. The core structure is &ospf_proto to which
* multiple &ospf_area and &ospf_iface structures are connected. &ospf_proto is
* also connected to &top_hash_graph which is a dynamic hashing structure that
* describes the link-state database. It allows fast search, addition and
* deletion. Each LSA is kept in two pieces: header and body. Both of them are
* kept in the endianity of the CPU.
*
* In OSPFv2 specification, it is implied that there is one IP prefix
* for each physical network/interface (unless it is an ptp link). But
* in modern systems, there might be more independent IP prefixes
* associated with an interface. To handle this situation, we have
* one &ospf_iface for each active IP prefix (instead for each active
* iface); This behaves like virtual interface for the purpose of OSPF.
* If we receive packet, we associate it with a proper virtual interface
* mainly according to its source address.
* In OSPFv2 specification, it is implied that there is one IP prefix for each
* physical network/interface (unless it is an ptp link). But in modern systems,
* there might be more independent IP prefixes associated with an interface. To
* handle this situation, we have one &ospf_iface for each active IP prefix
* (instead for each active iface); This behaves like virtual interface for the
* purpose of OSPF. If we receive packet, we associate it with a proper virtual
* interface mainly according to its source address.
*
* OSPF keeps one socket per &ospf_iface. This allows us (compared to
* one socket approach) to evade problems with a limit of multicast
* groups per socket and with sending multicast packets to appropriate
* interface in a portable way. The socket is associated with
* underlying physical iface and should not receive packets received
* on other ifaces (unfortunately, this is not true on
* BSD). Generally, one packet can be received by more sockets (for
* example, if there are more &ospf_iface on one physical iface),
* therefore we explicitly filter received packets according to
* src/dst IP address and received iface.
* OSPF keeps one socket per &ospf_iface. This allows us (compared to one socket
* approach) to evade problems with a limit of multicast groups per socket and
* with sending multicast packets to appropriate interface in a portable way.
* The socket is associated with underlying physical iface and should not
* receive packets received on other ifaces (unfortunately, this is not true on