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bird/proto/ospf/lsupd.c
Ondrej Zajicek (work) 1a2ad348f6 OSPF: Support for graceful restart
Implement OSPFv2 (RFC 3623) and OSPFv3 (RFC 5187) graceful restart,
for both restarting and helper sides. Graceful restart is initiated
by 'graceful down' command.
2019-06-30 21:30:41 +02:00

733 lines
18 KiB
C

/*
* BIRD -- OSPF
*
* (c) 2000--2004 Ondrej Filip <feela@network.cz>
* (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"
/*
struct ospf_lsupd_packet
{
struct ospf_packet hdr;
// union ospf_auth auth;
u32 lsa_count;
void lsas[];
};
*/
void
ospf_dump_lsahdr(struct ospf_proto *p, struct ospf_lsa_header *lsa_n)
{
struct ospf_lsa_header lsa;
u32 lsa_etype;
lsa_ntoh_hdr(lsa_n, &lsa);
lsa_etype = lsa_get_etype(&lsa, p);
log(L_TRACE "%s: LSA Type: %04x, Id: %R, Rt: %R, Seq: %08x, Age: %u, Sum: %04x",
p->p.name, lsa_etype, lsa.id, lsa.rt, lsa.sn, lsa.age, lsa.checksum);
}
void
ospf_dump_common(struct ospf_proto *p, struct ospf_packet *pkt)
{
log(L_TRACE "%s: length %d", p->p.name, ntohs(pkt->length));
log(L_TRACE "%s: router %R", p->p.name, ntohl(pkt->routerid));
}
static inline uint
ospf_lsupd_hdrlen(struct ospf_proto *p)
{
return ospf_pkt_hdrlen(p) + 4; /* + u32 lsa count field */
}
static inline u32
ospf_lsupd_get_lsa_count(struct ospf_packet *pkt, uint hdrlen)
{
u32 *c = ((void *) pkt) + hdrlen - 4;
return ntohl(*c);
}
static inline void
ospf_lsupd_set_lsa_count(struct ospf_packet *pkt, uint hdrlen, u32 val)
{
u32 *c = ((void *) pkt) + hdrlen - 4;
*c = htonl(val);
}
static inline void
ospf_lsupd_body(struct ospf_proto *p, struct ospf_packet *pkt,
uint *offset, uint *lsa_count)
{
uint hlen = ospf_lsupd_hdrlen(p);
*offset = hlen;
*lsa_count = ospf_lsupd_get_lsa_count(pkt, hlen);
}
static void
ospf_dump_lsupd(struct ospf_proto *p, struct ospf_packet *pkt)
{
uint offset, plen, i, lsa_count, lsa_len;
ASSERT(pkt->type == LSUPD_P);
ospf_dump_common(p, pkt);
plen = ntohs(pkt->length);
ospf_lsupd_body(p, pkt, &offset, &lsa_count);
for (i = 0; i < lsa_count; i++)
{
if ((offset + sizeof(struct ospf_lsa_header)) > plen)
goto invalid;
struct ospf_lsa_header *lsa = ((void *) pkt) + offset;
lsa_len = ntohs(lsa->length);
if (((lsa_len % 4) != 0) || (lsa_len <= sizeof(struct ospf_lsa_header)))
goto invalid;
ospf_dump_lsahdr(p, lsa);
offset += lsa_len;
}
return;
invalid:
log(L_TRACE "%s: LSA invalid", p->p.name);
return;
}
static inline void
ospf_lsa_lsrq_down(struct top_hash_entry *req, struct ospf_neighbor *n)
{
if (req == n->lsrqi)
n->lsrqi = SNODE_NEXT(req);
s_rem_node(SNODE req);
ospf_hash_delete(n->lsrqh, req);
if (EMPTY_SLIST(n->lsrql))
{
tm_stop(n->lsrq_timer);
if (n->state == NEIGHBOR_LOADING)
ospf_neigh_sm(n, INM_LOADDONE);
}
}
static inline void
ospf_lsa_lsrt_up(struct top_hash_entry *en, struct ospf_neighbor *n)
{
struct top_hash_entry *ret = ospf_hash_get_entry(n->lsrth, en);
if (!SNODE_VALID(ret))
{
en->ret_count++;
s_add_tail(&n->lsrtl, SNODE ret);
}
ret->lsa = en->lsa;
ret->lsa_body = LSA_BODY_DUMMY;
if (!tm_active(n->lsrt_timer))
tm_start(n->lsrt_timer, n->ifa->rxmtint S);
}
void
ospf_lsa_lsrt_down_(struct top_hash_entry *en, struct ospf_neighbor *n, struct top_hash_entry *ret)
{
if (en)
en->ret_count--;
s_rem_node(SNODE ret);
ospf_hash_delete(n->lsrth, ret);
if (EMPTY_SLIST(n->lsrtl))
tm_stop(n->lsrt_timer);
}
static inline int
ospf_lsa_lsrt_down(struct top_hash_entry *en, struct ospf_neighbor *n)
{
struct top_hash_entry *ret = ospf_hash_find_entry(n->lsrth, en);
if (ret)
ospf_lsa_lsrt_down_(en, n, ret);
return ret != NULL;
}
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) &&
lsa_is_acceptable(en->lsa_type, n, p))
ospf_lsa_lsrt_up(en, n);
/* If we found any flushed LSA, we send them ASAP */
if (tm_active(n->lsrt_timer))
tm_start(n->lsrt_timer, 0);
}
static int ospf_flood_lsupd(struct ospf_proto *p, struct top_hash_entry **lsa_list, uint lsa_count, uint lsa_min_count, struct ospf_iface *ifa);
static void
ospf_enqueue_lsa(struct ospf_proto *p, struct top_hash_entry *en, struct ospf_iface *ifa)
{
/* Exception for local Grace-LSA, they are flooded synchronously */
if ((en->lsa_type == LSA_T_GR) && (en->lsa.rt == p->router_id))
{
ospf_flood_lsupd(p, &en, 1, 1, ifa);
return;
}
if (ifa->flood_queue_used == ifa->flood_queue_size)
{
/* If we already have full queue, we send some packets */
uint sent = ospf_flood_lsupd(p, ifa->flood_queue, ifa->flood_queue_used, ifa->flood_queue_used / 2, ifa);
uint i;
for (i = 0; i < sent; i++)
ifa->flood_queue[i]->ret_count--;
ifa->flood_queue_used -= sent;
memmove(ifa->flood_queue, ifa->flood_queue + sent, ifa->flood_queue_used * sizeof(void *));
bzero(ifa->flood_queue + ifa->flood_queue_used, sent * sizeof(void *));
}
en->ret_count++;
ifa->flood_queue[ifa->flood_queue_used] = en;
ifa->flood_queue_used++;
if (!ev_active(p->flood_event))
ev_schedule(p->flood_event);
}
void
ospf_flood_event(void *ptr)
{
struct ospf_proto *p = ptr;
struct ospf_iface *ifa;
int i, count;
WALK_LIST(ifa, p->iface_list)
{
if (ifa->flood_queue_used == 0)
continue;
count = ifa->flood_queue_used;
ospf_flood_lsupd(p, ifa->flood_queue, count, count, ifa);
for (i = 0; i < count; i++)
ifa->flood_queue[i]->ret_count--;
ifa->flood_queue_used = 0;
bzero(ifa->flood_queue, count * sizeof(void *));
}
}
/**
* 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_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)
{
if (ifa->stub)
continue;
if (! lsa_flooding_allowed(en->lsa_type, en->domain, ifa))
continue;
DBG("Wanted to flood LSA: Type: %u, ID: %R, RT: %R, SN: 0x%x, Age %u\n",
hh->type, hh->id, hh->rt, hh->sn, hh->age);
int used = 0;
WALK_LIST(n, ifa->neigh_list)
{
/* 13.3 (1a) */
if (n->state < NEIGHBOR_EXCHANGE)
continue;
/* 13.3 (1b) */
if (n->state < NEIGHBOR_FULL)
{
struct top_hash_entry *req = ospf_hash_find_entry(n->lsrqh, en);
if (req != NULL)
{
int cmp = lsa_comp(&en->lsa, &req->lsa);
/* If same or newer, remove LSA from the link state request list */
if (cmp > CMP_OLDER)
ospf_lsa_lsrq_down(req, n);
/* If older or same, skip processing of this neighbor */
if (cmp < CMP_NEWER)
continue;
}
}
/* 13.3 (1c) */
if (n == from)
continue;
/* Check whether optional LSAs are supported by neighbor */
if (!lsa_is_acceptable(en->lsa_type, n, p))
continue;
/* 13.3 (1d) - add LSA to the link state retransmission list */
ospf_lsa_lsrt_up(en, n);
used = 1;
}
/* 13.3 (2) */
if (!used)
continue;
if (from && (from->ifa == ifa))
{
/* 13.3 (3) */
if ((from->rid == ifa->drid) || (from->rid == ifa->bdrid))
continue;
/* 13.3 (4) */
if (ifa->state == OSPF_IS_BACKUP)
continue;
back = 1;
}
/* 13.3 (5) - finally flood the packet */
ospf_enqueue_lsa(p, en, ifa);
}
return back;
}
static uint
ospf_prepare_lsupd(struct ospf_proto *p, struct ospf_iface *ifa,
struct top_hash_entry **lsa_list, uint lsa_count)
{
struct ospf_packet *pkt;
uint hlen, pos, i, maxsize;
pkt = ospf_tx_buffer(ifa);
hlen = ospf_lsupd_hdrlen(p);
maxsize = ospf_pkt_maxsize(ifa);
ospf_pkt_fill_hdr(ifa, pkt, LSUPD_P);
pos = hlen;
for (i = 0; i < lsa_count; i++)
{
struct top_hash_entry *en = lsa_list[i];
uint len = en->lsa.length;
if ((pos + len) > maxsize)
{
/* The packet if full, stop adding LSAs and sent it */
if (i > 0)
break;
/* LSA is larger than MTU, check buffer size */
if (ospf_iface_assure_bufsize(ifa, pos + len) < 0)
{
/* Cannot fit in a tx buffer, skip that */
log(L_ERR "%s: LSA too large to send on %s (Type: %04x, Id: %R, Rt: %R)",
p->p.name, ifa->ifname, en->lsa_type, en->lsa.id, en->lsa.rt);
break;
}
/* TX buffer could be reallocated */
pkt = ospf_tx_buffer(ifa);
}
struct ospf_lsa_header *buf = ((void *) pkt) + pos;
lsa_hton_hdr(&en->lsa, buf);
lsa_hton_body(en->lsa_body, ((void *) buf) + sizeof(struct ospf_lsa_header),
len - sizeof(struct ospf_lsa_header));
buf->age = htons(MIN(en->lsa.age + ifa->inftransdelay, LSA_MAXAGE));
pos += len;
}
ospf_lsupd_set_lsa_count(pkt, hlen, i);
pkt->length = htons(pos);
return i;
}
static int
ospf_flood_lsupd(struct ospf_proto *p, struct top_hash_entry **lsa_list, uint lsa_count, uint lsa_min_count, struct ospf_iface *ifa)
{
uint i, c;
for (i = 0; i < lsa_min_count; i += c)
{
c = ospf_prepare_lsupd(p, ifa, lsa_list + i, lsa_count - i);
if (!c) /* Too large LSA */
{ i++; continue; }
OSPF_PACKET(ospf_dump_lsupd, ospf_tx_buffer(ifa),
"LSUPD packet flooded via %s", ifa->ifname);
if (ifa->type == OSPF_IT_BCAST)
{
if ((ifa->state == OSPF_IS_DR) || (ifa->state == OSPF_IS_BACKUP))
ospf_send_to_all(ifa);
else
ospf_send_to_des(ifa);
}
else
ospf_send_to_agt(ifa, NEIGHBOR_EXCHANGE);
}
return i;
}
int
ospf_send_lsupd(struct ospf_proto *p, struct top_hash_entry **lsa_list, uint lsa_count, struct ospf_neighbor *n)
{
struct ospf_iface *ifa = n->ifa;
uint i, c;
for (i = 0; i < lsa_count; i += c)
{
c = ospf_prepare_lsupd(p, ifa, lsa_list + i, lsa_count - i);
if (!c) /* Too large LSA */
{ i++; continue; }
OSPF_PACKET(ospf_dump_lsupd, ospf_tx_buffer(ifa),
"LSUPD packet sent to nbr %R on %s", n->rid, ifa->ifname);
ospf_send_to(ifa, n->ip);
}
return i;
}
void
ospf_rxmt_lsupd(struct ospf_proto *p, struct ospf_neighbor *n)
{
uint max = 2 * n->ifa->flood_queue_size;
struct top_hash_entry *entries[max];
struct top_hash_entry *ret, *nxt, *en;
uint i = 0;
/* ASSERT((n->state >= NEIGHBOR_EXCHANGE) && !EMPTY_SLIST(n->lsrtl)); */
WALK_SLIST_DELSAFE(ret, nxt, n->lsrtl)
{
if (i == max)
break;
en = ospf_hash_find_entry(p->gr, ret);
if (!en)
{
/* Probably flushed LSA, this should not happen */
log(L_WARN "%s: LSA disappeared (Type: %04x, Id: %R, Rt: %R)",
p->p.name, ret->lsa_type, ret->lsa.id, ret->lsa.rt);
s_rem_node(SNODE ret);
ospf_hash_delete(n->lsrth, ret);
continue;
}
entries[i] = en;
i++;
}
ospf_send_lsupd(p, entries, i, n);
}
static inline int
ospf_addr_is_local(struct ospf_proto *p, struct ospf_area *oa, ip_addr ip)
{
struct ospf_iface *ifa;
WALK_LIST(ifa, p->iface_list)
if ((ifa->oa == oa) && ifa->addr && ipa_equal(ifa->addr->ip, ip))
return 1;
return 0;
}
void
ospf_receive_lsupd(struct ospf_packet *pkt, struct ospf_iface *ifa,
struct ospf_neighbor *n)
{
struct ospf_proto *p = ifa->oa->po;
const char *err_dsc = NULL;
uint plen, err_val = 0;
/* RFC 2328 13. */
plen = ntohs(pkt->length);
if (plen < ospf_lsupd_hdrlen(p))
{
LOG_PKT("Bad LSUPD packet from nbr %R on %s - %s (%u)", n->rid, ifa->ifname, "too short", plen);
return;
}
OSPF_PACKET(ospf_dump_lsupd, pkt, "LSUPD packet received from nbr %R on %s", n->rid, ifa->ifname);
if (n->state < NEIGHBOR_EXCHANGE)
{
OSPF_TRACE(D_PACKETS, "LSUPD packet ignored - lesser state than Exchange");
return;
}
ospf_neigh_sm(n, INM_HELLOREC); /* Questionable */
uint offset, i, lsa_count;
ospf_lsupd_body(p, pkt, &offset, &lsa_count);
for (i = 0; i < lsa_count; i++)
{
struct ospf_lsa_header lsa, *lsa_n;
struct top_hash_entry *en;
u32 lsa_len, lsa_type, lsa_domain;
if ((offset + sizeof(struct ospf_lsa_header)) > plen)
DROP("too short", plen);
/* LSA header in network order */
lsa_n = ((void *) pkt) + offset;
lsa_len = ntohs(lsa_n->length);
offset += lsa_len;
if (offset > plen)
DROP("too short", plen);
if (((lsa_len % 4) != 0) || (lsa_len <= sizeof(struct ospf_lsa_header)))
DROP("invalid LSA length", lsa_len);
/* LSA header in host order */
lsa_ntoh_hdr(lsa_n, &lsa);
lsa_get_type_domain(&lsa, ifa, &lsa_type, &lsa_domain);
DBG("Update Type: %04x, Id: %R, Rt: %R, Sn: 0x%08x, Age: %u, Sum: %u\n",
lsa_type, lsa.id, lsa.rt, lsa.sn, lsa.age, lsa.checksum);
/* RFC 2328 13. (1) - verify LSA checksum */
if ((lsa_n->checksum == 0) || !lsa_verify_checksum(lsa_n, lsa_len))
SKIP("invalid checksum");
/* RFC 2328 13. (2) */
if (!lsa_type)
SKIP("unknown type");
/* RFC 5340 4.5.1 (2) and RFC 2328 13. (3) */
if (!oa_is_ext(ifa->oa) && (LSA_SCOPE(lsa_type) == LSA_SCOPE_AS))
SKIP("AS scope in stub area");
/* Errata 3746 to RFC 2328 - rt-summary-LSAs forbidden in stub areas */
if (!oa_is_ext(ifa->oa) && (lsa_type == LSA_T_SUM_RT))
SKIP("rt-summary-LSA in stub area");
/* RFC 5340 4.5.1 (3) */
if (LSA_SCOPE(lsa_type) == LSA_SCOPE_RES)
SKIP("invalid scope");
/* Find local copy of LSA in link state database */
en = ospf_hash_find(p->gr, lsa_domain, lsa.id, lsa.rt, lsa_type);
#ifdef LOCAL_DEBUG
if (en)
DBG("I have Type: %04x, Id: %R, Rt: %R, Sn: 0x%08x, Age: %u, Sum: %u\n",
en->lsa_type, en->lsa.id, en->lsa.rt, en->lsa.sn, en->lsa.age, en->lsa.checksum);
#endif
/* 13. (4) - ignore maxage LSA if i have no local copy */
if ((lsa.age == LSA_MAXAGE) && !en && (p->padj == 0))
{
/* 13.5. - schedule ACKs (tbl 19, case 5) */
ospf_enqueue_lsack(n, lsa_n, ACKL_DIRECT);
continue;
}
/* 13. (5) - received LSA is newer (or no local copy) */
if (!en || (lsa_comp(&lsa, &en->lsa) == CMP_NEWER))
{
/* 13. (5a) - enforce minimum time between updates for received LSAs */
/* We also use this to ratelimit reactions to received self-originated LSAs */
if (en && (lsa_inst_age(en) < MINLSARRIVAL))
{
OSPF_TRACE(D_EVENTS, "Skipping LSA received in less that MinLSArrival");
continue;
}
/* Copy and validate LSA body */
int blen = lsa.length - sizeof(struct ospf_lsa_header);
void *body = mb_alloc(p->p.pool, blen);
lsa_ntoh_body(lsa_n + 1, body, blen);
if (lsa_validate(&lsa, lsa_type, ospf_is_v2(p), body) == 0)
{
mb_free(body);
SKIP("invalid body");
}
/* 13. (5f) - handle self-originated LSAs, see also 13.4. */
if (!p->gr_recovery &&
((lsa.rt == p->router_id) ||
(ospf_is_v2(p) && (lsa_type == LSA_T_NET) && ospf_addr_is_local(p, ifa->oa, ipa_from_u32(lsa.id)))))
{
OSPF_TRACE(D_EVENTS, "Received unexpected self-originated LSA");
ospf_advance_lsa(p, en, &lsa, lsa_type, lsa_domain, body);
continue;
}
/* 13. (5c) - remove old LSA from all retransmission lists
*
* 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
/*
* 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);
/* RFC 5340 4.4.3 Events 6+7 - new Link LSA received */
if (lsa_type == LSA_T_LINK)
ospf_notify_net_lsa(ifa);
/* RFC 3623 3.1 - entering graceful restart helper mode */
if (lsa_type == LSA_T_GR)
ospf_neigh_notify_grace_lsa(n, en);
/* Link received pre-restart router LSA */
if (p->gr_recovery && (lsa_type == LSA_T_RT) && (lsa.rt == p->router_id))
ifa->oa->rt = en;
/* 13. (5b) - flood new LSA */
int flood_back = ospf_flood_lsa(p, en, n);
/* 13.5. - schedule ACKs (tbl 19, cases 1+2) */
if (! flood_back)
if ((ifa->state != OSPF_IS_BACKUP) || (n->rid == ifa->drid))
ospf_enqueue_lsack(n, lsa_n, ACKL_DELAY);
/* FIXME: remove LSA entry if it is LSA_MAXAGE and it is possible? */
continue;
}
/* 13. (6) - received LSA is in Link state request list (but not newer) */
if (ospf_hash_find_entry(n->lsrqh, en) != NULL)
DROP1("error in LSA database exchange");
/* 13. (7) - received LSA is same */
if (lsa_comp(&lsa, &en->lsa) == CMP_SAME)
{
/* Duplicate LSA, treat as implicit ACK */
int implicit_ack = ospf_lsa_lsrt_down(en, n);
/* 13.5. - schedule ACKs (tbl 19, cases 3+4) */
if (implicit_ack)
{
if ((ifa->state == OSPF_IS_BACKUP) && (n->rid == ifa->drid))
ospf_enqueue_lsack(n, lsa_n, ACKL_DELAY);
}
else
ospf_enqueue_lsack(n, lsa_n, ACKL_DIRECT);
continue;
}
/* 13. (8) - received LSA is older */
{
/* Seqnum is wrapping, wait until it is flushed */
if ((en->lsa.age == LSA_MAXAGE) && (en->lsa.sn == LSA_MAXSEQNO))
continue;
/* Send newer local copy back to neighbor */
/* FIXME - check for MinLSArrival ? */
ospf_send_lsupd(p, &en, 1, n);
continue;
}
skip:
LOG_LSA1("Bad LSA (Type: %04x, Id: %R, Rt: %R) in LSUPD", lsa_type, lsa.id, lsa.rt);
LOG_LSA2(" received from nbr %R on %s - %s", n->rid, ifa->ifname, err_dsc);
}
/* Send direct LSACKs */
ospf_send_lsack(p, n, ACKL_DIRECT);
/* Send enqueued LSAs immediately, do not wait for flood_event */
if (ev_active(p->flood_event))
{
ev_postpone(p->flood_event);
ospf_flood_event(p);
}
/*
* During loading, we should ask for another batch of LSAs. This is only
* vaguely mentioned in RFC 2328. We send a new LSREQ if all requests sent in
* the last packet were already answered and/or removed from the LS request
* list and therefore lsrqi is pointing to the first node of the list.
*/
if (!EMPTY_SLIST(n->lsrql) && (n->lsrqi == SHEAD(n->lsrql)))
{
ospf_send_lsreq(p, n);
tm_start(n->lsrq_timer, n->ifa->rxmtint S);
}
return;
drop:
LOG_PKT("Bad LSUPD packet from nbr %R on %s - %s (%u)",
n->rid, ifa->ifname, err_dsc, err_val);
/* Malformed LSUPD - there is no defined error event, we abuse BadLSReq */
ospf_neigh_sm(n, INM_BADLSREQ);
return;
}