0
0
mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-12-24 18:51:54 +00:00
bird/proto/ospf/dbdes.c
Ondrej Zajicek (work) bc591061f6 OSPF: Packets on PtP networks should be always sent to AllSPFRouters
As specified in RFC 2328 8.1: "On physical point-to-point networks,
the IP destination is always set to the address AllSPFRouters."

Note that this likely break setups with multiple neighbors on a network
configured as PtP, which worked before. These should be configured as
PtMP.

Thanks to Senthil Kumar Nagappan for the original patch and to Joakim
Tjernlund for suggestions.
2021-05-09 15:26:13 +02:00

511 lines
12 KiB
C

/*
* BIRD -- OSPF
*
* (c) 1999--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_dbdes2_packet
{
struct ospf_packet hdr;
union ospf_auth2 auth;
u16 iface_mtu;
u8 options;
u8 imms; /* I, M, MS bits */
u32 ddseq;
struct ospf_lsa_header lsas[];
};
struct ospf_dbdes3_packet
{
struct ospf_packet hdr;
u32 options;
u16 iface_mtu;
u8 padding;
u8 imms; /* I, M, MS bits */
u32 ddseq;
struct ospf_lsa_header lsas[];
};
uint
ospf_dbdes3_options(struct ospf_packet *pkt)
{
struct ospf_dbdes3_packet *ps = (void *) pkt;
return ntohl(ps->options);
}
static inline uint
ospf_dbdes_hdrlen(struct ospf_proto *p)
{
return ospf_is_v2(p) ?
sizeof(struct ospf_dbdes2_packet) : sizeof(struct ospf_dbdes3_packet);
}
static void
ospf_dbdes_body(struct ospf_proto *p, struct ospf_packet *pkt,
struct ospf_lsa_header **body, uint *count)
{
uint plen = ntohs(pkt->length);
uint hlen = ospf_dbdes_hdrlen(p);
*body = ((void *) pkt) + hlen;
*count = (plen - hlen) / sizeof(struct ospf_lsa_header);
}
static void
ospf_dump_dbdes(struct ospf_proto *p, struct ospf_packet *pkt)
{
struct ospf_lsa_header *lsas;
uint i, lsa_count;
u32 pkt_ddseq;
u16 pkt_iface_mtu;
u8 pkt_imms;
ASSERT(pkt->type == DBDES_P);
ospf_dump_common(p, pkt);
if (ospf_is_v2(p))
{
struct ospf_dbdes2_packet *ps = (void *) pkt;
pkt_iface_mtu = ntohs(ps->iface_mtu);
pkt_imms = ps->imms;
pkt_ddseq = ntohl(ps->ddseq);
}
else /* OSPFv3 */
{
struct ospf_dbdes3_packet *ps = (void *) pkt;
pkt_iface_mtu = ntohs(ps->iface_mtu);
pkt_imms = ps->imms;
pkt_ddseq = ntohl(ps->ddseq);
}
log(L_TRACE "%s: mtu %u", p->p.name, pkt_iface_mtu);
log(L_TRACE "%s: imms %s%s%s", p->p.name,
(pkt_imms & DBDES_I) ? "I " : "",
(pkt_imms & DBDES_M) ? "M " : "",
(pkt_imms & DBDES_MS) ? "MS" : "");
log(L_TRACE "%s: ddseq %u", p->p.name, pkt_ddseq);
ospf_dbdes_body(p, pkt, &lsas, &lsa_count);
for (i = 0; i < lsa_count; i++)
ospf_dump_lsahdr(p, lsas + i);
}
static void
ospf_prepare_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)
{
struct ospf_iface *ifa = n->ifa;
struct ospf_packet *pkt;
uint length;
u16 iface_mtu = (ifa->type == OSPF_IT_VLINK) ? 0 : ifa->iface->mtu;
/* Update DBDES buffer */
if (n->ldd_bsize != ifa->tx_length)
{
mb_free(n->ldd_buffer);
n->ldd_buffer = mb_allocz(n->pool, ifa->tx_length);
n->ldd_bsize = ifa->tx_length;
}
pkt = n->ldd_buffer;
ospf_pkt_fill_hdr(ifa, pkt, DBDES_P);
if (ospf_is_v2(p))
{
struct ospf_dbdes2_packet *ps = (void *) pkt;
ps->iface_mtu = htons(iface_mtu);
ps->options = ifa->oa->options & DBDES2_OPT_MASK;
ps->imms = 0; /* Will be set later */
ps->ddseq = htonl(n->dds);
length = sizeof(struct ospf_dbdes2_packet);
}
else /* OSPFv3 */
{
struct ospf_dbdes3_packet *ps = (void *) pkt;
u32 options = ifa->oa->options | (ifa->autype == OSPF_AUTH_CRYPT ? OPT_AT : 0);
ps->options = htonl(options & DBDES3_OPT_MASK);
ps->iface_mtu = htons(iface_mtu);
ps->padding = 0;
ps->imms = 0; /* Will be set later */
ps->ddseq = htonl(n->dds);
length = sizeof(struct ospf_dbdes3_packet);
}
/* Prepare DBDES body */
if (!(n->myimms & DBDES_I) && (n->myimms & DBDES_M))
{
struct ospf_lsa_header *lsas;
struct top_hash_entry *en;
uint i = 0, lsa_max;
ospf_dbdes_body(p, pkt, &lsas, &lsa_max);
en = (void *) s_get(&(n->dbsi));
while (i < lsa_max)
{
if (!SNODE_VALID(en))
{
n->myimms &= ~DBDES_M; /* Unset More bit */
break;
}
if ((en->lsa.age < LSA_MAXAGE) &&
lsa_flooding_allowed(en->lsa_type, en->domain, ifa) &&
lsa_is_acceptable(en->lsa_type, n, p))
{
lsa_hton_hdr(&(en->lsa), lsas + i);
i++;
}
en = SNODE_NEXT(en);
}
s_put(&(n->dbsi), SNODE en);
length += i * sizeof(struct ospf_lsa_header);
}
if (ospf_is_v2(p))
((struct ospf_dbdes2_packet *) pkt)->imms = n->myimms;
else
((struct ospf_dbdes3_packet *) pkt)->imms = n->myimms;
pkt->length = htons(length);
}
static void
ospf_do_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)
{
struct ospf_iface *ifa = n->ifa;
OSPF_PACKET(ospf_dump_dbdes, n->ldd_buffer,
"DBDES packet sent to nbr %R on %s", n->rid, ifa->ifname);
sk_set_tbuf(ifa->sk, n->ldd_buffer);
ospf_send_to_nbr(ifa, n);
sk_set_tbuf(ifa->sk, NULL);
}
/**
* ospf_send_dbdes - transmit database description packet
* @p: OSPF protocol instance
* @n: neighbor
*
* Sending of a database description packet is described in 10.8 of RFC 2328.
* Reception of each packet is acknowledged in the sequence number of another.
* When I send a packet to a neighbor I keep a copy in a buffer. If the neighbor
* does not reply, I don't create a new packet but just send the content
* of the buffer.
*/
void
ospf_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)
{
/* RFC 2328 10.8 */
ASSERT((n->state == NEIGHBOR_EXSTART) || (n->state == NEIGHBOR_EXCHANGE));
if (!n->ifa->oa->rt && !p->gr_recovery)
return;
ospf_prepare_dbdes(p, n);
ospf_do_send_dbdes(p, n);
}
void
ospf_rxmt_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)
{
ASSERT(n->state > NEIGHBOR_EXSTART);
if (!n->ldd_buffer)
{
log(L_WARN "%s: No DBDES packet for retransmit", p->p.name);
ospf_neigh_sm(n, INM_SEQMIS);
return;
}
/* Send last packet */
ospf_do_send_dbdes(p, n);
}
void
ospf_reset_ldd(struct ospf_proto *p UNUSED, struct ospf_neighbor *n)
{
mb_free(n->ldd_buffer);
n->ldd_buffer = NULL;
n->ldd_bsize = 0;
}
static int
ospf_process_dbdes(struct ospf_proto *p, struct ospf_packet *pkt, struct ospf_neighbor *n)
{
struct ospf_iface *ifa = n->ifa;
struct ospf_lsa_header *lsas, lsa;
struct top_hash_entry *en, *req;
const char *err_dsc = NULL;
u32 lsa_type, lsa_domain;
uint i, lsa_count;
ospf_dbdes_body(p, pkt, &lsas, &lsa_count);
for (i = 0; i < lsa_count; i++)
{
lsa_ntoh_hdr(lsas + i, &lsa);
lsa_get_type_domain(&lsa, ifa, &lsa_type, &lsa_domain);
/* RFC 2328 10.6 and RFC 5340 4.2.2 */
if (!lsa_type)
DROP1("LSA of unknown type");
if (!oa_is_ext(ifa->oa) && (LSA_SCOPE(lsa_type) == LSA_SCOPE_AS))
DROP1("LSA with 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))
DROP1("rt-summary-LSA in stub area");
/* Not explicitly mentioned in RFC 5340 4.2.2 but makes sense */
if (LSA_SCOPE(lsa_type) == LSA_SCOPE_RES)
DROP1("LSA with invalid scope");
/* RFC 3623 2.2 (2) special case - check for my router-LSA (GR recovery) */
if ((lsa_type == LSA_T_RT) && (lsa.rt == p->router_id))
n->got_my_rt_lsa = 1;
en = ospf_hash_find(p->gr, lsa_domain, lsa.id, lsa.rt, lsa_type);
if (!en || (lsa_comp(&lsa, &(en->lsa)) == CMP_NEWER))
{
/* This should be splitted to ospf_lsa_lsrq_up() */
req = ospf_hash_get(n->lsrqh, lsa_domain, lsa.id, lsa.rt, lsa_type);
if (!SNODE_VALID(req))
s_add_tail(&n->lsrql, SNODE req);
if (!SNODE_VALID(n->lsrqi))
n->lsrqi = req;
req->lsa = lsa;
req->lsa_body = LSA_BODY_DUMMY;
if (!tm_active(n->lsrq_timer))
tm_start(n->lsrq_timer, 0);
}
}
return 0;
drop:
LOG_LSA1("Bad LSA (Type: %04x, Id: %R, Rt: %R) in DBDES", lsa_type, lsa.id, lsa.rt);
LOG_LSA2(" received from nbr %R on %s - %s", n->rid, ifa->ifname, err_dsc);
ospf_neigh_sm(n, INM_SEQMIS);
return -1;
}
void
ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
struct ospf_neighbor *n)
{
struct ospf_proto *p = ifa->oa->po;
const char *err_dsc = NULL;
u32 rcv_ddseq, rcv_options;
u16 rcv_iface_mtu;
u8 rcv_imms;
uint plen, err_val = 0;
/* RFC 2328 10.6 */
plen = ntohs(pkt->length);
if (plen < ospf_dbdes_hdrlen(p))
{
LOG_PKT("Bad DBDES packet from nbr %R on %s - %s (%u)", n->rid, ifa->ifname, "too short", plen);
return;
}
OSPF_PACKET(ospf_dump_dbdes, pkt, "DBDES packet received from nbr %R on %s", n->rid, ifa->ifname);
ospf_neigh_sm(n, INM_HELLOREC);
if (ospf_is_v2(p))
{
struct ospf_dbdes2_packet *ps = (void *) pkt;
rcv_iface_mtu = ntohs(ps->iface_mtu);
rcv_options = ps->options;
rcv_imms = ps->imms;
rcv_ddseq = ntohl(ps->ddseq);
}
else /* OSPFv3 */
{
struct ospf_dbdes3_packet *ps = (void *) pkt;
rcv_options = ntohl(ps->options);
rcv_iface_mtu = ntohs(ps->iface_mtu);
rcv_imms = ps->imms;
rcv_ddseq = ntohl(ps->ddseq);
}
/* Reject packets with non-matching MTU */
if ((ifa->type != OSPF_IT_VLINK) &&
(rcv_iface_mtu != ifa->iface->mtu) &&
(rcv_iface_mtu != 0) && (ifa->iface->mtu != 0))
{
LOG_PKT("MTU mismatch with nbr %R on %s (remote %d, local %d)",
n->rid, ifa->ifname, rcv_iface_mtu, ifa->iface->mtu);
return;
}
switch (n->state)
{
case NEIGHBOR_DOWN:
case NEIGHBOR_ATTEMPT:
case NEIGHBOR_2WAY:
OSPF_TRACE(D_PACKETS, "DBDES packet ignored - lesser state than ExStart");
return;
case NEIGHBOR_INIT:
ospf_neigh_sm(n, INM_2WAYREC);
if (n->state != NEIGHBOR_EXSTART)
return;
/* fallthrough */
case NEIGHBOR_EXSTART:
if (((rcv_imms & DBDES_IMMS) == DBDES_IMMS) &&
(n->rid > p->router_id) &&
(plen == ospf_dbdes_hdrlen(p)))
{
/* I'm slave! */
n->dds = rcv_ddseq;
n->ddr = rcv_ddseq;
n->options = rcv_options;
n->myimms &= ~DBDES_MS;
n->imms = rcv_imms;
tm_stop(n->dbdes_timer);
ospf_neigh_sm(n, INM_NEGDONE);
ospf_send_dbdes(p, n);
break;
}
if (!(rcv_imms & DBDES_I) &&
!(rcv_imms & DBDES_MS) &&
(n->rid < p->router_id) &&
(n->dds == rcv_ddseq))
{
/* I'm master! */
n->options = rcv_options;
n->ddr = rcv_ddseq - 1; /* It will be set corectly a few lines down */
n->imms = rcv_imms;
ospf_neigh_sm(n, INM_NEGDONE);
/* Continue to the NEIGHBOR_EXCHANGE case */
}
else
{
DBG("%s: Nothing happend to %I (imms=%d)\n", p->name, n->ip, rcv_imms);
break;
}
case NEIGHBOR_EXCHANGE:
if ((rcv_imms == n->imms) &&
(rcv_options == n->options) &&
(rcv_ddseq == n->ddr))
goto duplicate;
if ((rcv_imms & DBDES_MS) != (n->imms & DBDES_MS))
DROP("MS-bit mismatch", rcv_imms);
if (rcv_imms & DBDES_I)
DROP("I-bit mismatch", rcv_imms);
if (rcv_options != n->options)
DROP("options mismatch", rcv_options);
n->ddr = rcv_ddseq;
n->imms = rcv_imms;
if (n->myimms & DBDES_MS)
{
/* MASTER */
if (rcv_ddseq != n->dds)
DROP("DD sequence number mismatch", rcv_ddseq);
n->dds++;
if (ospf_process_dbdes(p, pkt, n) < 0)
return;
if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))
{
tm_stop(n->dbdes_timer);
ospf_reset_ldd(p, n);
ospf_neigh_sm(n, INM_EXDONE);
break;
}
ospf_send_dbdes(p, n);
tm_start(n->dbdes_timer, n->ifa->rxmtint S);
}
else
{
/* SLAVE */
if (rcv_ddseq != (n->dds + 1))
DROP("DD sequence number mismatch", rcv_ddseq);
n->ddr = rcv_ddseq;
n->dds = rcv_ddseq;
if (ospf_process_dbdes(p, pkt, n) < 0)
return;
ospf_send_dbdes(p, n);
if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))
{
/* Use dbdes timer to postpone freeing of Last DBDES packet buffer */
tm_start(n->dbdes_timer, n->ifa->deadint S);
ospf_neigh_sm(n, INM_EXDONE);
}
}
break;
case NEIGHBOR_LOADING:
case NEIGHBOR_FULL:
if ((rcv_imms == n->imms) &&
(rcv_options == n->options) &&
(rcv_ddseq == n->ddr))
goto duplicate;
DROP("too late for DD exchange", n->state);
default:
bug("Undefined interface state");
}
return;
duplicate:
OSPF_TRACE(D_PACKETS, "DBDES packet is duplicate");
/* Slave should retransmit DBDES packet */
if (!(n->myimms & DBDES_MS))
ospf_rxmt_dbdes(p, n);
return;
drop:
LOG_PKT("Bad DBDES packet from nbr %R on %s - %s (%u)",
n->rid, ifa->ifname, err_dsc, err_val);
ospf_neigh_sm(n, INM_SEQMIS);
return;
}