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bird/proto/bgp/packets.c
Ondrej Zajicek (work) c0fc3e6718 The MRT protocol 
The new MRT protocol is responsible for periodic RIB table dumps in the
MRT format (RFC 6396). Also the existing code for BGP4MP MRT dumps is
refactored and splitted between BGP to MRT protocols, will be more
integrated into MRT in the future.

Example:

protocol mrt {
	table "*";
	filename "%N_%F_%T.mrt";
	period 60;
}

It is partially based on the old MRT code from Pavel Tvrdik.
2018-09-18 17:50:45 +02:00

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/*
* BIRD -- BGP Packet Processing
*
* (c) 2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "nest/attrs.h"
#include "proto/mrt/mrt.h"
#include "conf/conf.h"
#include "lib/unaligned.h"
#include "lib/socket.h"
#include "nest/cli.h"
#include "bgp.h"
#define BGP_RR_REQUEST 0
#define BGP_RR_BEGIN 1
#define BGP_RR_END 2
static struct tbf rl_rcv_update = TBF_DEFAULT_LOG_LIMITS;
static struct tbf rl_snd_update = TBF_DEFAULT_LOG_LIMITS;
/* Table for state -> RFC 6608 FSM error subcodes */
static byte fsm_err_subcode[BS_MAX] = {
[BS_OPENSENT] = 1,
[BS_OPENCONFIRM] = 2,
[BS_ESTABLISHED] = 3
};
static void
init_mrt_bgp_data(struct bgp_conn *conn, struct mrt_bgp_data *d)
{
struct bgp_proto *p = conn->bgp;
int p_ok = conn->state >= BS_OPENCONFIRM;
memset(d, 0, sizeof(struct mrt_bgp_data));
d->peer_as = p->remote_as;
d->local_as = p->local_as;
d->index = (p->neigh && p->neigh->iface) ? p->neigh->iface->index : 0;
d->af = BGP_AF;
d->peer_ip = conn->sk ? conn->sk->daddr : IPA_NONE;
d->local_ip = conn->sk ? conn->sk->saddr : IPA_NONE;
d->as4 = p_ok ? p->as4_session : 0;
d->add_path = p_ok ? p->add_path_rx : 0;
}
static void
bgp_dump_message(struct bgp_conn *conn, byte *pkt, uint len)
{
struct mrt_bgp_data d;
init_mrt_bgp_data(conn, &d);
d.message = pkt;
d.msg_len = len;
mrt_dump_bgp_message(&d);
}
void
bgp_dump_state_change(struct bgp_conn *conn, uint old, uint new)
{
struct mrt_bgp_data d;
init_mrt_bgp_data(conn, &d);
d.old_state = old;
d.new_state = new;
mrt_dump_bgp_state_change(&d);
}
static byte *
bgp_create_notification(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Sending NOTIFICATION(code=%d.%d)", conn->notify_code, conn->notify_subcode);
buf[0] = conn->notify_code;
buf[1] = conn->notify_subcode;
memcpy(buf+2, conn->notify_data, conn->notify_size);
return buf + 2 + conn->notify_size;
}
#ifdef IPV6
static byte *
bgp_put_cap_ipv6(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 1; /* Capability 1: Multiprotocol extensions */
*buf++ = 4; /* Capability data length */
*buf++ = 0; /* We support AF IPv6 */
*buf++ = BGP_AF_IPV6;
*buf++ = 0; /* RFU */
*buf++ = 1; /* and SAFI 1 */
return buf;
}
#else
static byte *
bgp_put_cap_ipv4(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 1; /* Capability 1: Multiprotocol extensions */
*buf++ = 4; /* Capability data length */
*buf++ = 0; /* We support AF IPv4 */
*buf++ = BGP_AF_IPV4;
*buf++ = 0; /* RFU */
*buf++ = 1; /* and SAFI 1 */
return buf;
}
#endif
static byte *
bgp_put_cap_rr(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 2; /* Capability 2: Support for route refresh */
*buf++ = 0; /* Capability data length */
return buf;
}
static byte *
bgp_put_cap_ext_msg(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 6; /* Capability 6: Support for extended messages */
*buf++ = 0; /* Capability data length */
return buf;
}
static byte *
bgp_put_cap_gr1(struct bgp_proto *p, byte *buf)
{
*buf++ = 64; /* Capability 64: Support for graceful restart */
*buf++ = 6; /* Capability data length */
put_u16(buf, p->cf->gr_time);
if (p->p.gr_recovery)
buf[0] |= BGP_GRF_RESTART;
buf += 2;
*buf++ = 0; /* Appropriate AF */
*buf++ = BGP_AF;
*buf++ = 1; /* and SAFI 1 */
*buf++ = p->p.gr_recovery ? BGP_GRF_FORWARDING : 0;
return buf;
}
static byte *
bgp_put_cap_gr2(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 64; /* Capability 64: Support for graceful restart */
*buf++ = 2; /* Capability data length */
put_u16(buf, 0);
return buf + 2;
}
static byte *
bgp_put_cap_as4(struct bgp_proto *p, byte *buf)
{
*buf++ = 65; /* Capability 65: Support for 4-octet AS number */
*buf++ = 4; /* Capability data length */
put_u32(buf, p->local_as);
return buf + 4;
}
static byte *
bgp_put_cap_add_path(struct bgp_proto *p, byte *buf)
{
*buf++ = 69; /* Capability 69: Support for ADD-PATH */
*buf++ = 4; /* Capability data length */
*buf++ = 0; /* Appropriate AF */
*buf++ = BGP_AF;
*buf++ = 1; /* SAFI 1 */
*buf++ = p->cf->add_path;
return buf;
}
static byte *
bgp_put_cap_err(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 70; /* Capability 70: Support for enhanced route refresh */
*buf++ = 0; /* Capability data length */
return buf;
}
static byte *
bgp_put_cap_llgr1(struct bgp_proto *p, byte *buf)
{
*buf++ = 71; /* Capability 71: Support for long-lived graceful restart */
*buf++ = 7; /* Capability data length */
*buf++ = 0; /* Appropriate AF */
*buf++ = BGP_AF;
*buf++ = 1; /* and SAFI 1 */
/* Next is 8bit flags and 24bit time */
put_u32(buf, p->cf->llgr_time);
buf[0] = p->p.gr_recovery ? BGP_LLGRF_FORWARDING : 0;
buf += 4;
return buf;
}
static byte *
bgp_put_cap_llgr2(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 71; /* Capability 71: Support for long-lived graceful restart */
*buf++ = 0; /* Capability data length */
return buf;
}
static byte *
bgp_create_open(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
byte *cap;
int cap_len;
BGP_TRACE(D_PACKETS, "Sending OPEN(ver=%d,as=%d,hold=%d,id=%08x)",
BGP_VERSION, p->local_as, p->cf->hold_time, p->local_id);
buf[0] = BGP_VERSION;
put_u16(buf+1, (p->local_as < 0xFFFF) ? p->local_as : AS_TRANS);
put_u16(buf+3, p->cf->hold_time);
put_u32(buf+5, p->local_id);
if (conn->start_state == BSS_CONNECT_NOCAP)
{
BGP_TRACE(D_PACKETS, "Skipping capabilities");
buf[9] = 0;
return buf + 10;
}
/* Skipped 3 B for length field and Capabilities parameter header */
cap = buf + 12;
#ifndef IPV6
if (p->cf->advertise_ipv4)
cap = bgp_put_cap_ipv4(p, cap);
#endif
#ifdef IPV6
cap = bgp_put_cap_ipv6(p, cap);
#endif
if (p->cf->enable_refresh)
cap = bgp_put_cap_rr(p, cap);
if (p->cf->gr_mode == BGP_GR_ABLE)
cap = bgp_put_cap_gr1(p, cap);
else if (p->cf->gr_mode == BGP_GR_AWARE)
cap = bgp_put_cap_gr2(p, cap);
if (p->cf->enable_as4)
cap = bgp_put_cap_as4(p, cap);
if (p->cf->add_path)
cap = bgp_put_cap_add_path(p, cap);
if (p->cf->enable_refresh)
cap = bgp_put_cap_err(p, cap);
if (p->cf->enable_extended_messages)
cap = bgp_put_cap_ext_msg(p, cap);
if (p->cf->llgr_mode == BGP_LLGR_ABLE)
cap = bgp_put_cap_llgr1(p, cap);
else if (p->cf->llgr_mode == BGP_LLGR_AWARE)
cap = bgp_put_cap_llgr2(p, cap);
cap_len = cap - buf - 12;
if (cap_len > 0)
{
buf[9] = cap_len + 2; /* Optional params len */
buf[10] = 2; /* Option: Capability list */
buf[11] = cap_len; /* Option length */
return cap;
}
else
{
buf[9] = 0; /* No optional parameters */
return buf + 10;
}
}
static uint
bgp_encode_prefixes(struct bgp_proto *p, byte *w, struct bgp_bucket *buck, uint remains)
{
byte *start = w;
ip_addr a;
int bytes;
while (!EMPTY_LIST(buck->prefixes) && (remains >= (5+sizeof(ip_addr))))
{
struct bgp_prefix *px = SKIP_BACK(struct bgp_prefix, bucket_node, HEAD(buck->prefixes));
DBG("\tDequeued route %I/%d\n", px->n.prefix, px->n.pxlen);
if (p->add_path_tx)
{
put_u32(w, px->path_id);
w += 4;
remains -= 4;
}
*w++ = px->n.pxlen;
bytes = (px->n.pxlen + 7) / 8;
a = px->n.prefix;
ipa_hton(a);
memcpy(w, &a, bytes);
w += bytes;
remains -= bytes + 1;
rem_node(&px->bucket_node);
bgp_free_prefix(p, px);
// fib_delete(&p->prefix_fib, px);
}
return w - start;
}
static void
bgp_flush_prefixes(struct bgp_proto *p, struct bgp_bucket *buck)
{
while (!EMPTY_LIST(buck->prefixes))
{
struct bgp_prefix *px = SKIP_BACK(struct bgp_prefix, bucket_node, HEAD(buck->prefixes));
log(L_ERR "%s: - route %I/%d skipped", p->p.name, px->n.prefix, px->n.pxlen);
rem_node(&px->bucket_node);
bgp_free_prefix(p, px);
// fib_delete(&p->prefix_fib, px);
}
}
#ifndef IPV6 /* IPv4 version */
static byte *
bgp_create_update(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
struct bgp_bucket *buck;
int remains = bgp_max_packet_length(p) - BGP_HEADER_LENGTH - 4;
byte *w;
int wd_size = 0;
int r_size = 0;
int a_size = 0;
w = buf+2;
if ((buck = p->withdraw_bucket) && !EMPTY_LIST(buck->prefixes))
{
DBG("Withdrawn routes:\n");
wd_size = bgp_encode_prefixes(p, w, buck, remains);
w += wd_size;
remains -= wd_size;
}
put_u16(buf, wd_size);
if (!wd_size)
{
while ((buck = (struct bgp_bucket *) HEAD(p->bucket_queue))->send_node.next)
{
if (EMPTY_LIST(buck->prefixes))
{
DBG("Deleting empty bucket %p\n", buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
}
DBG("Processing bucket %p\n", buck);
a_size = bgp_encode_attrs(p, w+2, buck->eattrs, remains - 1024);
if (a_size < 0)
{
log(L_ERR "%s: Attribute list too long, skipping corresponding routes", p->p.name);
bgp_flush_prefixes(p, buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
}
put_u16(w, a_size);
w += a_size + 2;
r_size = bgp_encode_prefixes(p, w, buck, remains - a_size);
w += r_size;
break;
}
}
if (!a_size) /* Attributes not already encoded */
{
put_u16(w, 0);
w += 2;
}
if (wd_size || r_size)
{
BGP_TRACE_RL(&rl_snd_update, D_PACKETS, "Sending UPDATE");
return w;
}
else
return NULL;
}
static byte *
bgp_create_end_mark(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Sending END-OF-RIB");
put_u32(buf, 0);
return buf+4;
}
#else /* IPv6 version */
static inline int
same_iface(struct bgp_proto *p, ip_addr *ip)
{
neighbor *n = neigh_find(&p->p, ip, 0);
return n && p->neigh && n->iface == p->neigh->iface;
}
static byte *
bgp_create_update(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
struct bgp_bucket *buck;
int size, second, rem_stored;
int remains = bgp_max_packet_length(p) - BGP_HEADER_LENGTH - 4;
byte *w, *w_stored, *tmp, *tstart;
ip_addr *ipp, ip, ip_ll;
ea_list *ea;
eattr *nh;
put_u16(buf, 0);
w = buf+4;
if ((buck = p->withdraw_bucket) && !EMPTY_LIST(buck->prefixes))
{
DBG("Withdrawn routes:\n");
tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_UNREACH_NLRI, remains-8);
*tmp++ = 0;
*tmp++ = BGP_AF_IPV6;
*tmp++ = 1;
ea->attrs[0].u.ptr->length = 3 + bgp_encode_prefixes(p, tmp, buck, remains-11);
size = bgp_encode_attrs(p, w, ea, remains);
ASSERT(size >= 0);
w += size;
remains -= size;
}
else
{
while ((buck = (struct bgp_bucket *) HEAD(p->bucket_queue))->send_node.next)
{
if (EMPTY_LIST(buck->prefixes))
{
DBG("Deleting empty bucket %p\n", buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
}
DBG("Processing bucket %p\n", buck);
rem_stored = remains;
w_stored = w;
size = bgp_encode_attrs(p, w, buck->eattrs, remains - 1024);
if (size < 0)
{
log(L_ERR "%s: Attribute list too long, skipping corresponding routes", p->p.name);
bgp_flush_prefixes(p, buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
}
w += size;
remains -= size;
/* We have two addresses here in NEXT_HOP eattr. Really.
Unless NEXT_HOP was modified by filter */
nh = ea_find(buck->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
ASSERT(nh);
second = (nh->u.ptr->length == NEXT_HOP_LENGTH);
ipp = (ip_addr *) nh->u.ptr->data;
ip = ipp[0];
ip_ll = IPA_NONE;
if (ipa_equal(ip, p->source_addr))
ip_ll = p->local_link;
else
{
/* If we send a route with 'third party' next hop destinated
* in the same interface, we should also send a link local
* next hop address. We use the received one (stored in the
* other part of BA_NEXT_HOP eattr). If we didn't received
* it (for example it is a static route), we can't use
* 'third party' next hop and we have to use local IP address
* as next hop. Sending original next hop address without
* link local address seems to be a natural way to solve that
* problem, but it is contrary to RFC 2545 and Quagga does not
* accept such routes.
*
* There are two cases, either we have global IP, or
* IPA_NONE if the neighbor is link-local. For IPA_NONE,
* we suppose it is on the same iface, see bgp_update_attrs().
*/
if (ipa_zero(ip) || same_iface(p, &ip))
{
if (second && ipa_nonzero(ipp[1]))
ip_ll = ipp[1];
else
{
switch (p->cf->missing_lladdr)
{
case MLL_SELF:
ip = p->source_addr;
ip_ll = p->local_link;
break;
case MLL_DROP:
log(L_ERR "%s: Missing link-local next hop address, skipping corresponding routes", p->p.name);
w = w_stored;
remains = rem_stored;
bgp_flush_prefixes(p, buck);
rem_node(&buck->send_node);
bgp_free_bucket(p, buck);
continue;
case MLL_IGNORE:
break;
}
}
}
}
tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
*tmp++ = 0;
*tmp++ = BGP_AF_IPV6;
*tmp++ = 1;
if (ipa_is_link_local(ip))
ip = IPA_NONE;
if (ipa_nonzero(ip_ll))
{
*tmp++ = 32;
ipa_hton(ip);
memcpy(tmp, &ip, 16);
ipa_hton(ip_ll);
memcpy(tmp+16, &ip_ll, 16);
tmp += 32;
}
else
{
*tmp++ = 16;
ipa_hton(ip);
memcpy(tmp, &ip, 16);
tmp += 16;
}
*tmp++ = 0; /* No SNPA information */
tmp += bgp_encode_prefixes(p, tmp, buck, remains - (8+3+32+1));
ea->attrs[0].u.ptr->length = tmp - tstart;
size = bgp_encode_attrs(p, w, ea, remains);
ASSERT(size >= 0);
w += size;
break;
}
}
size = w - (buf+4);
put_u16(buf+2, size);
lp_flush(bgp_linpool);
if (size)
{
BGP_TRACE_RL(&rl_snd_update, D_PACKETS, "Sending UPDATE");
return w;
}
else
return NULL;
}
static byte *
bgp_create_end_mark(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Sending END-OF-RIB");
put_u16(buf+0, 0);
put_u16(buf+2, 6); /* length 4-9 */
buf += 4;
/* Empty MP_UNREACH_NLRI atribute */
*buf++ = BAF_OPTIONAL;
*buf++ = BA_MP_UNREACH_NLRI;
*buf++ = 3; /* Length 7-9 */
*buf++ = 0; /* AFI */
*buf++ = BGP_AF_IPV6;
*buf++ = 1; /* SAFI */
return buf;
}
#endif
static inline byte *
bgp_create_route_refresh(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Sending ROUTE-REFRESH");
/* Original original route refresh request, RFC 2918 */
*buf++ = 0;
*buf++ = BGP_AF;
*buf++ = BGP_RR_REQUEST;
*buf++ = 1; /* SAFI */
return buf;
}
static inline byte *
bgp_create_begin_refresh(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Sending BEGIN-OF-RR");
/* Demarcation of beginning of route refresh (BoRR), RFC 7313 */
*buf++ = 0;
*buf++ = BGP_AF;
*buf++ = BGP_RR_BEGIN;
*buf++ = 1; /* SAFI */
return buf;
}
static inline byte *
bgp_create_end_refresh(struct bgp_conn *conn, byte *buf)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Sending END-OF-RR");
/* Demarcation of ending of route refresh (EoRR), RFC 7313 */
*buf++ = 0;
*buf++ = BGP_AF;
*buf++ = BGP_RR_END;
*buf++ = 1; /* SAFI */
return buf;
}
static void
bgp_create_header(byte *buf, uint len, uint type)
{
memset(buf, 0xff, 16); /* Marker */
put_u16(buf+16, len);
buf[18] = type;
}
/**
* bgp_fire_tx - transmit packets
* @conn: connection
*
* Whenever the transmit buffers of the underlying TCP connection
* are free and we have any packets queued for sending, the socket functions
* call bgp_fire_tx() which takes care of selecting the highest priority packet
* queued (Notification > Keepalive > Open > Update), assembling its header
* and body and sending it to the connection.
*/
static int
bgp_fire_tx(struct bgp_conn *conn)
{
struct bgp_proto *p = conn->bgp;
uint s = conn->packets_to_send;
sock *sk = conn->sk;
byte *buf, *pkt, *end;
int type;
if (!sk)
{
conn->packets_to_send = 0;
return 0;
}
buf = sk->tbuf;
pkt = buf + BGP_HEADER_LENGTH;
if (s & (1 << PKT_SCHEDULE_CLOSE))
{
/* We can finally close connection and enter idle state */
bgp_conn_enter_idle_state(conn);
return 0;
}
if (s & (1 << PKT_NOTIFICATION))
{
s = 1 << PKT_SCHEDULE_CLOSE;
type = PKT_NOTIFICATION;
end = bgp_create_notification(conn, pkt);
}
else if (s & (1 << PKT_KEEPALIVE))
{
s &= ~(1 << PKT_KEEPALIVE);
type = PKT_KEEPALIVE;
end = pkt; /* Keepalives carry no data */
BGP_TRACE(D_PACKETS, "Sending KEEPALIVE");
bgp_start_timer(conn->keepalive_timer, conn->keepalive_time);
}
else if (s & (1 << PKT_OPEN))
{
s &= ~(1 << PKT_OPEN);
type = PKT_OPEN;
end = bgp_create_open(conn, pkt);
}
else if (s & (1 << PKT_ROUTE_REFRESH))
{
s &= ~(1 << PKT_ROUTE_REFRESH);
type = PKT_ROUTE_REFRESH;
end = bgp_create_route_refresh(conn, pkt);
}
else if (s & (1 << PKT_BEGIN_REFRESH))
{
s &= ~(1 << PKT_BEGIN_REFRESH);
type = PKT_ROUTE_REFRESH; /* BoRR is a subtype of RR */
end = bgp_create_begin_refresh(conn, pkt);
}
else if (s & (1 << PKT_UPDATE))
{
type = PKT_UPDATE;
end = bgp_create_update(conn, pkt);
if (!end)
{
/* No update to send, perhaps we need to send End-of-RIB or EoRR */
conn->packets_to_send = 0;
if (p->feed_state == BFS_LOADED)
{
type = PKT_UPDATE;
end = bgp_create_end_mark(conn, pkt);
}
else if (p->feed_state == BFS_REFRESHED)
{
type = PKT_ROUTE_REFRESH;
end = bgp_create_end_refresh(conn, pkt);
}
else /* Really nothing to send */
return 0;
p->feed_state = BFS_NONE;
}
}
else
return 0;
conn->packets_to_send = s;
bgp_create_header(buf, end - buf, type);
return sk_send(sk, end - buf);
}
/**
* bgp_schedule_packet - schedule a packet for transmission
* @conn: connection
* @type: packet type
*
* Schedule a packet of type @type to be sent as soon as possible.
*/
void
bgp_schedule_packet(struct bgp_conn *conn, int type)
{
DBG("BGP: Scheduling packet type %d\n", type);
conn->packets_to_send |= 1 << type;
if (conn->sk && conn->sk->tpos == conn->sk->tbuf && !ev_active(conn->tx_ev))
ev_schedule(conn->tx_ev);
}
void
bgp_kick_tx(void *vconn)
{
struct bgp_conn *conn = vconn;
DBG("BGP: kicking TX\n");
while (bgp_fire_tx(conn) > 0)
;
}
void
bgp_tx(sock *sk)
{
struct bgp_conn *conn = sk->data;
DBG("BGP: TX hook\n");
while (bgp_fire_tx(conn) > 0)
;
}
/* Capatibility negotiation as per RFC 2842 */
void
bgp_parse_capabilities(struct bgp_conn *conn, byte *opt, int len)
{
// struct bgp_proto *p = conn->bgp;
int i, cl;
while (len > 0)
{
if (len < 2 || len < 2 + opt[1])
goto err;
cl = opt[1];
switch (opt[0])
{
case 2: /* Route refresh capability, RFC 2918 */
if (cl != 0)
goto err;
conn->peer_refresh_support = 1;
break;
case 6: /* Extended message length capability, draft */
if (cl != 0)
goto err;
conn->peer_ext_messages_support = 1;
break;
case 64: /* Graceful restart capability, RFC 4724 */
if (cl % 4 != 2)
goto err;
conn->peer_gr_aware = 1;
conn->peer_gr_able = 0;
conn->peer_gr_time = get_u16(opt + 2) & 0x0fff;
conn->peer_gr_flags = opt[2] & 0xf0;
conn->peer_gr_aflags = 0;
for (i = 2; i < cl; i += 4)
if (opt[2+i+0] == 0 && opt[2+i+1] == BGP_AF && opt[2+i+2] == 1) /* Match AFI/SAFI */
{
conn->peer_gr_able = 1;
conn->peer_gr_aflags = opt[2+i+3];
}
break;
case 65: /* AS4 capability, RFC 4893 */
if (cl != 4)
goto err;
conn->peer_as4_support = 1;
if (conn->bgp->cf->enable_as4)
conn->advertised_as = get_u32(opt + 2);
break;
case 69: /* ADD-PATH capability, RFC 7911 */
if (cl % 4)
goto err;
for (i = 0; i < cl; i += 4)
if (opt[2+i+0] == 0 && opt[2+i+1] == BGP_AF && opt[2+i+2] == 1) /* Match AFI/SAFI */
conn->peer_add_path = opt[2+i+3];
if (conn->peer_add_path > ADD_PATH_FULL)
goto err;
break;
case 70: /* Enhanced route refresh capability, RFC 7313 */
if (cl != 0)
goto err;
conn->peer_enhanced_refresh_support = 1;
break;
case 71: /* Long-lived graceful restart capability, RFC draft */
if (cl % 7)
goto err;
conn->peer_llgr_aware = 1;
conn->peer_llgr_able = 0;
conn->peer_llgr_time = 0;
conn->peer_llgr_aflags = 0;
for (i = 0; i < cl; i += 7)
if (opt[2+i+0] == 0 && opt[2+i+1] == BGP_AF && opt[2+i+2] == 1) /* Match AFI/SAFI */
{
conn->peer_llgr_able = 1;
conn->peer_llgr_time = get_u32(opt + 2+i+3) & 0xffffff;
conn->peer_llgr_aflags = opt[2+i+3];
}
break;
/* We can safely ignore all other capabilities */
}
len -= 2 + cl;
opt += 2 + cl;
}
/* The LLGR capability must be advertised together with the GR capability,
otherwise it must be disregarded */
if (!conn->peer_gr_aware && conn->peer_llgr_aware)
{
conn->peer_llgr_aware = 0;
conn->peer_llgr_able = 0;
conn->peer_llgr_time = 0;
conn->peer_llgr_aflags = 0;
}
return;
err:
bgp_error(conn, 2, 0, NULL, 0);
return;
}
static int
bgp_parse_options(struct bgp_conn *conn, byte *opt, int len)
{
struct bgp_proto *p = conn->bgp;
int ol;
while (len > 0)
{
if (len < 2 || len < 2 + opt[1])
{ bgp_error(conn, 2, 0, NULL, 0); return 0; }
#ifdef LOCAL_DEBUG
{
int i;
DBG("\tOption %02x:", opt[0]);
for(i=0; i<opt[1]; i++)
DBG(" %02x", opt[2+i]);
DBG("\n");
}
#endif
ol = opt[1];
switch (opt[0])
{
case 2:
if (conn->start_state == BSS_CONNECT_NOCAP)
BGP_TRACE(D_PACKETS, "Ignoring received capabilities");
else
bgp_parse_capabilities(conn, opt + 2, ol);
break;
default:
/*
* BGP specs don't tell us to send which option
* we didn't recognize, but it's common practice
* to do so. Also, capability negotiation with
* Cisco routers doesn't work without that.
*/
bgp_error(conn, 2, 4, opt, ol);
return 0;
}
len -= 2 + ol;
opt += 2 + ol;
}
return 0;
}
static void
bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
{
struct bgp_conn *other;
struct bgp_proto *p = conn->bgp;
unsigned hold;
u16 base_as;
u32 id;
/* Check state */
if (conn->state != BS_OPENSENT)
{ bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); return; }
/* Check message contents */
if (len < 29 || len != 29U + pkt[28])
{ bgp_error(conn, 1, 2, pkt+16, 2); return; }
if (pkt[19] != BGP_VERSION)
{ bgp_error(conn, 2, 1, pkt+19, 1); return; } /* RFC 1771 says 16 bits, draft-09 tells to use 8 */
conn->advertised_as = base_as = get_u16(pkt+20);
hold = get_u16(pkt+22);
id = get_u32(pkt+24);
BGP_TRACE(D_PACKETS, "Got OPEN(as=%d,hold=%d,id=%08x)", conn->advertised_as, hold, id);
if (bgp_parse_options(conn, pkt+29, pkt[28]))
return;
if (hold > 0 && hold < 3)
{ bgp_error(conn, 2, 6, pkt+22, 2); return; }
/* RFC 6286 2.2 - router ID is nonzero and AS-wide unique */
if (!id || (p->is_internal && id == p->local_id))
{ bgp_error(conn, 2, 3, pkt+24, -4); return; }
if ((conn->advertised_as != base_as) && (base_as != AS_TRANS))
log(L_WARN "%s: Peer advertised inconsistent AS numbers", p->p.name);
if (conn->advertised_as != p->remote_as)
{
if (conn->peer_as4_support)
{
u32 val = htonl(conn->advertised_as);
bgp_error(conn, 2, 2, (byte *) &val, 4);
}
else
bgp_error(conn, 2, 2, pkt+20, 2);
return;
}
/* Check the other connection */
other = (conn == &p->outgoing_conn) ? &p->incoming_conn : &p->outgoing_conn;
switch (other->state)
{
case BS_CONNECT:
case BS_ACTIVE:
/* Stop outgoing connection attempts */
bgp_conn_enter_idle_state(other);
break;
case BS_IDLE:
case BS_OPENSENT:
case BS_CLOSE:
break;
case BS_OPENCONFIRM:
/*
* Description of collision detection rules in RFC 4271 is confusing and
* contradictory, but it is essentially:
*
* 1. Router with higher ID is dominant
* 2. If both have the same ID, router with higher ASN is dominant [RFC6286]
* 3. When both connections are in OpenConfirm state, one initiated by
* the dominant router is kept.
*
* The first line in the expression below evaluates whether the neighbor
* is dominant, the second line whether the new connection was initiated
* by the neighbor. If both are true (or both are false), we keep the new
* connection, otherwise we keep the old one.
*/
if (((p->local_id < id) || ((p->local_id == id) && (p->local_as < p->remote_as)))
== (conn == &p->incoming_conn))
{
/* Should close the other connection */
BGP_TRACE(D_EVENTS, "Connection collision, giving up the other connection");
bgp_error(other, 6, 7, NULL, 0);
break;
}
/* Fall thru */
case BS_ESTABLISHED:
/* Should close this connection */
BGP_TRACE(D_EVENTS, "Connection collision, giving up this connection");
bgp_error(conn, 6, 7, NULL, 0);
return;
default:
bug("bgp_rx_open: Unknown state");
}
/* Update our local variables */
conn->hold_time = MIN(hold, p->cf->hold_time);
conn->keepalive_time = p->cf->keepalive_time ? : conn->hold_time / 3;
p->remote_id = id;
p->as4_session = p->cf->enable_as4 && conn->peer_as4_support;
p->add_path_rx = (p->cf->add_path & ADD_PATH_RX) && (conn->peer_add_path & ADD_PATH_TX);
p->add_path_tx = (p->cf->add_path & ADD_PATH_TX) && (conn->peer_add_path & ADD_PATH_RX);
p->gr_ready = (p->cf->gr_mode && conn->peer_gr_able) ||
(p->cf->llgr_mode && conn->peer_llgr_able);
p->ext_messages = p->cf->enable_extended_messages && conn->peer_ext_messages_support;
/* Update RA mode */
if (p->add_path_tx)
p->p.accept_ra_types = RA_ANY;
else if (p->cf->secondary)
p->p.accept_ra_types = RA_ACCEPTED;
else
p->p.accept_ra_types = RA_OPTIMAL;
DBG("BGP: Hold timer set to %d, keepalive to %d, AS to %d, ID to %x, AS4 session to %d\n", conn->hold_time, conn->keepalive_time, p->remote_as, p->remote_id, p->as4_session);
bgp_schedule_packet(conn, PKT_KEEPALIVE);
bgp_start_timer(conn->hold_timer, conn->hold_time);
bgp_conn_enter_openconfirm_state(conn);
}
static inline void
bgp_rx_end_mark(struct bgp_proto *p)
{
BGP_TRACE(D_PACKETS, "Got END-OF-RIB");
if (p->load_state == BFS_LOADING)
p->load_state = BFS_NONE;
if (p->p.gr_recovery)
proto_graceful_restart_unlock(&p->p);
if (p->gr_active)
bgp_graceful_restart_done(p);
}
#define DECODE_PREFIX(pp, ll) do { \
if (p->add_path_rx) \
{ \
if (ll < 5) { err=1; goto done; } \
path_id = get_u32(pp); \
pp += 4; \
ll -= 4; \
} \
int b = *pp++; \
int q; \
ll--; \
if (b > BITS_PER_IP_ADDRESS) { err=10; goto done; } \
q = (b+7) / 8; \
if (ll < q) { err=1; goto done; } \
memcpy(&prefix, pp, q); \
pp += q; \
ll -= q; \
ipa_ntoh(prefix); \
prefix = ipa_and(prefix, ipa_mkmask(b)); \
pxlen = b; \
} while (0)
static inline void
bgp_rte_update(struct bgp_proto *p, ip_addr prefix, int pxlen,
u32 path_id, u32 *last_id, struct rte_src **src,
rta *a0, rta **a)
{
if (path_id != *last_id)
{
*src = rt_get_source(&p->p, path_id);
*last_id = path_id;
if (*a)
{
rta_free(*a);
*a = NULL;
}
}
/* Prepare cached route attributes */
if (!*a)
{
a0->src = *src;
/* Workaround for rta_lookup() breaking eattrs */
ea_list *ea = a0->eattrs;
*a = rta_lookup(a0);
a0->eattrs = ea;
}
net *n = net_get(p->p.table, prefix, pxlen);
rte *e = rte_get_temp(rta_clone(*a));
e->net = n;
e->pflags = 0;
e->u.bgp.suppressed = 0;
e->u.bgp.stale = -1;
rte_update2(p->p.main_ahook, n, e, *src);
}
static inline void
bgp_rte_withdraw(struct bgp_proto *p, ip_addr prefix, int pxlen,
u32 path_id, u32 *last_id, struct rte_src **src)
{
if (path_id != *last_id)
{
*src = rt_find_source(&p->p, path_id);
*last_id = path_id;
}
net *n = net_find(p->p.table, prefix, pxlen);
rte_update2( p->p.main_ahook, n, NULL, *src);
}
static inline int
bgp_set_next_hop(struct bgp_proto *p, rta *a)
{
struct eattr *nh = ea_find(a->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
ip_addr *nexthop = (ip_addr *) nh->u.ptr->data;
#ifdef IPV6
int second = (nh->u.ptr->length == NEXT_HOP_LENGTH) && ipa_nonzero(nexthop[1]);
/* First address should not be link-local, but may be zero in direct mode */
if (ipa_is_link_local(*nexthop))
*nexthop = IPA_NONE;
#else
int second = 0;
#endif
if (p->cf->gw_mode == GW_DIRECT)
{
neighbor *ng = NULL;
if (ipa_nonzero(*nexthop))
ng = neigh_find(&p->p, nexthop, 0);
else if (second) /* GW_DIRECT -> single_hop -> p->neigh != NULL */
ng = neigh_find2(&p->p, nexthop + 1, p->neigh->iface, 0);
/* Fallback */
if (!ng)
ng = p->neigh;
if (ng->scope == SCOPE_HOST)
return 0;
a->dest = RTD_ROUTER;
a->gw = ng->addr;
a->iface = ng->iface;
a->hostentry = NULL;
a->igp_metric = 0;
}
else /* GW_RECURSIVE */
{
if (ipa_zero(*nexthop))
return 0;
rta_set_recursive_next_hop(p->p.table, a, p->igp_table, nexthop, nexthop + second);
}
return 1;
}
#ifndef IPV6 /* IPv4 version */
static void
bgp_do_rx_update(struct bgp_conn *conn,
byte *withdrawn, int withdrawn_len,
byte *nlri, int nlri_len,
byte *attrs, int attr_len)
{
struct bgp_proto *p = conn->bgp;
struct rte_src *src = p->p.main_source;
rta *a0, *a = NULL;
ip_addr prefix;
int pxlen, err = 0;
u32 path_id = 0;
u32 last_id = 0;
/* Check for End-of-RIB marker */
if (!withdrawn_len && !attr_len && !nlri_len)
{
bgp_rx_end_mark(p);
return;
}
/* Withdraw routes */
while (withdrawn_len)
{
DECODE_PREFIX(withdrawn, withdrawn_len);
DBG("Withdraw %I/%d\n", prefix, pxlen);
bgp_rte_withdraw(p, prefix, pxlen, path_id, &last_id, &src);
}
if (!attr_len && !nlri_len) /* shortcut */
return;
a0 = bgp_decode_attrs(conn, attrs, attr_len, bgp_linpool, nlri_len);
if (conn->state != BS_ESTABLISHED) /* fatal error during decoding */
return;
if (a0 && nlri_len && !bgp_set_next_hop(p, a0))
a0 = NULL;
last_id = 0;
src = p->p.main_source;
while (nlri_len)
{
DECODE_PREFIX(nlri, nlri_len);
DBG("Add %I/%d\n", prefix, pxlen);
if (a0)
bgp_rte_update(p, prefix, pxlen, path_id, &last_id, &src, a0, &a);
else /* Forced withdraw as a result of soft error */
bgp_rte_withdraw(p, prefix, pxlen, path_id, &last_id, &src);
}
done:
if (a)
rta_free(a);
if (err)
bgp_error(conn, 3, err, NULL, 0);
return;
}
#else /* IPv6 version */
#define DO_NLRI(name) \
x = p->name##_start; \
len = len0 = p->name##_len; \
if (len) \
{ \
if (len < 3) { err=9; goto done; } \
af = get_u16(x); \
x += 3; \
len -= 3; \
DBG("\tNLRI AF=%d sub=%d len=%d\n", af, x[-1], len);\
} \
else \
af = 0; \
if (af == BGP_AF_IPV6)
static void
bgp_attach_next_hop(rta *a0, byte *x)
{
ip_addr *nh = (ip_addr *) bgp_attach_attr_wa(&a0->eattrs, bgp_linpool, BA_NEXT_HOP, NEXT_HOP_LENGTH);
memcpy(nh, x+1, 16);
ipa_ntoh(nh[0]);
/* We store received link local address in the other part of BA_NEXT_HOP eattr. */
if (*x == 32)
{
memcpy(nh+1, x+17, 16);
ipa_ntoh(nh[1]);
}
else
nh[1] = IPA_NONE;
}
static void
bgp_do_rx_update(struct bgp_conn *conn,
byte *withdrawn UNUSED, int withdrawn_len,
byte *nlri UNUSED, int nlri_len,
byte *attrs, int attr_len)
{
struct bgp_proto *p = conn->bgp;
struct rte_src *src = p->p.main_source;
byte *x;
int len, len0;
unsigned af;
rta *a0, *a = NULL;
ip_addr prefix;
int pxlen, err = 0;
u32 path_id = 0;
u32 last_id = 0;
p->mp_reach_len = 0;
p->mp_unreach_len = 0;
a0 = bgp_decode_attrs(conn, attrs, attr_len, bgp_linpool, 0);
if (conn->state != BS_ESTABLISHED) /* fatal error during decoding */
return;
/* Check for End-of-RIB marker */
if ((attr_len < 8) && !withdrawn_len && !nlri_len && !p->mp_reach_len &&
(p->mp_unreach_len == 3) && (get_u16(p->mp_unreach_start) == BGP_AF_IPV6))
{
bgp_rx_end_mark(p);
return;
}
DO_NLRI(mp_unreach)
{
while (len)
{
DECODE_PREFIX(x, len);
DBG("Withdraw %I/%d\n", prefix, pxlen);
bgp_rte_withdraw(p, prefix, pxlen, path_id, &last_id, &src);
}
}
DO_NLRI(mp_reach)
{
/* Create fake NEXT_HOP attribute */
if (len < 1 || (*x != 16 && *x != 32) || len < *x + 2)
{ err = 9; goto done; }
if (a0)
bgp_attach_next_hop(a0, x);
/* Also ignore one reserved byte */
len -= *x + 2;
x += *x + 2;
if (a0 && ! bgp_set_next_hop(p, a0))
a0 = NULL;
last_id = 0;
src = p->p.main_source;
while (len)
{
DECODE_PREFIX(x, len);
DBG("Add %I/%d\n", prefix, pxlen);
if (a0)
bgp_rte_update(p, prefix, pxlen, path_id, &last_id, &src, a0, &a);
else /* Forced withdraw as a result of soft error */
bgp_rte_withdraw(p, prefix, pxlen, path_id, &last_id, &src);
}
}
done:
if (a)
rta_free(a);
if (err) /* Use subcode 9, not err */
bgp_error(conn, 3, 9, NULL, 0);
return;
}
#endif
static void
bgp_rx_update(struct bgp_conn *conn, byte *pkt, uint len)
{
struct bgp_proto *p = conn->bgp;
byte *withdrawn, *attrs, *nlri;
uint withdrawn_len, attr_len, nlri_len;
BGP_TRACE_RL(&rl_rcv_update, D_PACKETS, "Got UPDATE");
/* Workaround for some BGP implementations that skip initial KEEPALIVE */
if (conn->state == BS_OPENCONFIRM)
bgp_conn_enter_established_state(conn);
if (conn->state != BS_ESTABLISHED)
{ bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); return; }
bgp_start_timer(conn->hold_timer, conn->hold_time);
/* Find parts of the packet and check sizes */
if (len < 23)
{
bgp_error(conn, 1, 2, pkt+16, 2);
return;
}
withdrawn = pkt + 21;
withdrawn_len = get_u16(pkt + 19);
if (withdrawn_len + 23 > len)
goto malformed;
attrs = withdrawn + withdrawn_len + 2;
attr_len = get_u16(attrs - 2);
if (withdrawn_len + attr_len + 23 > len)
goto malformed;
nlri = attrs + attr_len;
nlri_len = len - withdrawn_len - attr_len - 23;
if (!attr_len && nlri_len)
goto malformed;
DBG("Sizes: withdrawn=%d, attrs=%d, NLRI=%d\n", withdrawn_len, attr_len, nlri_len);
lp_flush(bgp_linpool);
bgp_do_rx_update(conn, withdrawn, withdrawn_len, nlri, nlri_len, attrs, attr_len);
return;
malformed:
bgp_error(conn, 3, 1, NULL, 0);
}
static struct {
byte major, minor;
byte *msg;
} bgp_msg_table[] = {
{ 1, 0, "Invalid message header" },
{ 1, 1, "Connection not synchronized" },
{ 1, 2, "Bad message length" },
{ 1, 3, "Bad message type" },
{ 2, 0, "Invalid OPEN message" },
{ 2, 1, "Unsupported version number" },
{ 2, 2, "Bad peer AS" },
{ 2, 3, "Bad BGP identifier" },
{ 2, 4, "Unsupported optional parameter" },
{ 2, 5, "Authentication failure" },
{ 2, 6, "Unacceptable hold time" },
{ 2, 7, "Required capability missing" }, /* [RFC5492] */
{ 2, 8, "No supported AFI/SAFI" }, /* This error msg is nonstandard */
{ 3, 0, "Invalid UPDATE message" },
{ 3, 1, "Malformed attribute list" },
{ 3, 2, "Unrecognized well-known attribute" },
{ 3, 3, "Missing mandatory attribute" },
{ 3, 4, "Invalid attribute flags" },
{ 3, 5, "Invalid attribute length" },
{ 3, 6, "Invalid ORIGIN attribute" },
{ 3, 7, "AS routing loop" }, /* Deprecated */
{ 3, 8, "Invalid NEXT_HOP attribute" },
{ 3, 9, "Optional attribute error" },
{ 3, 10, "Invalid network field" },
{ 3, 11, "Malformed AS_PATH" },
{ 4, 0, "Hold timer expired" },
{ 5, 0, "Finite state machine error" }, /* Subcodes are according to [RFC6608] */
{ 5, 1, "Unexpected message in OpenSent state" },
{ 5, 2, "Unexpected message in OpenConfirm state" },
{ 5, 3, "Unexpected message in Established state" },
{ 6, 0, "Cease" }, /* Subcodes are according to [RFC4486] */
{ 6, 1, "Maximum number of prefixes reached" },
{ 6, 2, "Administrative shutdown" },
{ 6, 3, "Peer de-configured" },
{ 6, 4, "Administrative reset" },
{ 6, 5, "Connection rejected" },
{ 6, 6, "Other configuration change" },
{ 6, 7, "Connection collision resolution" },
{ 6, 8, "Out of Resources" },
{ 7, 0, "Invalid ROUTE-REFRESH message" }, /* [RFC7313] */
{ 7, 1, "Invalid ROUTE-REFRESH message length" } /* [RFC7313] */
};
/**
* bgp_error_dsc - return BGP error description
* @code: BGP error code
* @subcode: BGP error subcode
*
* bgp_error_dsc() returns error description for BGP errors
* which might be static string or given temporary buffer.
*/
const char *
bgp_error_dsc(unsigned code, unsigned subcode)
{
static char buff[32];
unsigned i;
for (i=0; i < ARRAY_SIZE(bgp_msg_table); i++)
if (bgp_msg_table[i].major == code && bgp_msg_table[i].minor == subcode)
{
return bgp_msg_table[i].msg;
}
bsprintf(buff, "Unknown error %d.%d", code, subcode);
return buff;
}
/* RFC 8203 - shutdown communication message */
static int
bgp_handle_message(struct bgp_proto *p, byte *data, uint len, byte **bp)
{
byte *msg = data + 1;
uint msg_len = data[0];
uint i;
/* Handle zero length message */
if (msg_len == 0)
return 1;
/* Handle proper message */
if ((msg_len > 128) && (msg_len + 1 > len))
return 0;
/* Some elementary cleanup */
for (i = 0; i < msg_len; i++)
if (msg[i] < ' ')
msg[i] = ' ';
proto_set_message(&p->p, msg, msg_len);
*bp += bsprintf(*bp, ": \"%s\"", p->p.message);
return 1;
}
void
bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsigned subcode, byte *data, unsigned len)
{
byte argbuf[256], *t = argbuf;
unsigned i;
/* Don't report Cease messages generated by myself */
if (code == 6 && class == BE_BGP_TX)
return;
/* Reset shutdown message */
if ((code == 6) && ((subcode == 2) || (subcode == 4)))
proto_set_message(&p->p, NULL, 0);
if (len)
{
/* Bad peer AS - we would like to print the AS */
if ((code == 2) && (subcode == 2) && ((len == 2) || (len == 4)))
{
t += bsprintf(t, ": %u", (len == 2) ? get_u16(data) : get_u32(data));
goto done;
}
/* RFC 8203 - shutdown communication */
if (((code == 6) && ((subcode == 2) || (subcode == 4))))
if (bgp_handle_message(p, data, len, &t))
goto done;
*t++ = ':';
*t++ = ' ';
if (len > 16)
len = 16;
for (i=0; i<len; i++)
t += bsprintf(t, "%02x", data[i]);
}
done:
*t = 0;
const byte *dsc = bgp_error_dsc(code, subcode);
log(L_REMOTE "%s: %s: %s%s", p->p.name, msg, dsc, argbuf);
}
static void
bgp_rx_notification(struct bgp_conn *conn, byte *pkt, uint len)
{
struct bgp_proto *p = conn->bgp;
if (len < 21)
{
bgp_error(conn, 1, 2, pkt+16, 2);
return;
}
unsigned code = pkt[19];
unsigned subcode = pkt[20];
int err = (code != 6);
bgp_log_error(p, BE_BGP_RX, "Received", code, subcode, pkt+21, len-21);
bgp_store_error(p, conn, BE_BGP_RX, (code << 16) | subcode);
#ifndef IPV6
if ((code == 2) && ((subcode == 4) || (subcode == 7))
/* Error related to capability:
* 4 - Peer does not support capabilities at all.
* 7 - Peer request some capability. Strange unless it is IPv6 only peer.
*/
&& (p->cf->capabilities == 2)
/* Capabilities are not explicitly enabled or disabled, therefore heuristic is used */
&& (conn->start_state == BSS_CONNECT)
/* Failed connection attempt have used capabilities */
&& (p->cf->remote_as <= 0xFFFF))
/* Not possible with disabled capabilities */
{
/* We try connect without capabilities */
log(L_WARN "%s: Capability related error received, retry with capabilities disabled", p->p.name);
p->start_state = BSS_CONNECT_NOCAP;
err = 0;
}
#endif
bgp_conn_enter_close_state(conn);
bgp_schedule_packet(conn, PKT_SCHEDULE_CLOSE);
if (err)
{
bgp_update_startup_delay(p);
bgp_stop(p, 0, NULL, 0);
}
else
{
uint subcode_bit = 1 << ((subcode <= 8) ? subcode : 0);
if (p->cf->disable_after_cease & subcode_bit)
{
log(L_INFO "%s: Disabled after Cease notification", p->p.name);
p->startup_delay = 0;
p->p.disabled = 1;
}
}
}
static void
bgp_rx_keepalive(struct bgp_conn *conn)
{
struct bgp_proto *p = conn->bgp;
BGP_TRACE(D_PACKETS, "Got KEEPALIVE");
bgp_start_timer(conn->hold_timer, conn->hold_time);
switch (conn->state)
{
case BS_OPENCONFIRM:
bgp_conn_enter_established_state(conn);
break;
case BS_ESTABLISHED:
break;
default:
bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0);
}
}
static void
bgp_rx_route_refresh(struct bgp_conn *conn, byte *pkt, uint len)
{
struct bgp_proto *p = conn->bgp;
if (conn->state != BS_ESTABLISHED)
{ bgp_error(conn, 5, fsm_err_subcode[conn->state], NULL, 0); return; }
if (!p->cf->enable_refresh)
{ bgp_error(conn, 1, 3, pkt+18, 1); return; }
if (len < (BGP_HEADER_LENGTH + 4))
{ bgp_error(conn, 1, 2, pkt+16, 2); return; }
if (len > (BGP_HEADER_LENGTH + 4))
{ bgp_error(conn, 7, 1, pkt, MIN(len, 2048)); return; }
/* FIXME - we ignore AFI/SAFI values, as we support
just one value and even an error code for an invalid
request is not defined */
/* RFC 7313 redefined reserved field as RR message subtype */
uint subtype = conn->peer_enhanced_refresh_support ? pkt[21] : BGP_RR_REQUEST;
switch (subtype)
{
case BGP_RR_REQUEST:
BGP_TRACE(D_PACKETS, "Got ROUTE-REFRESH");
proto_request_feeding(&p->p);
break;
case BGP_RR_BEGIN:
BGP_TRACE(D_PACKETS, "Got BEGIN-OF-RR");
bgp_refresh_begin(p);
break;
case BGP_RR_END:
BGP_TRACE(D_PACKETS, "Got END-OF-RR");
bgp_refresh_end(p);
break;
default:
log(L_WARN "%s: Got ROUTE-REFRESH message with unknown subtype %u, ignoring",
p->p.name, subtype);
break;
}
}
/**
* bgp_rx_packet - handle a received packet
* @conn: BGP connection
* @pkt: start of the packet
* @len: packet size
*
* bgp_rx_packet() takes a newly received packet and calls the corresponding
* packet handler according to the packet type.
*/
static void
bgp_rx_packet(struct bgp_conn *conn, byte *pkt, unsigned len)
{
byte type = pkt[18];
DBG("BGP: Got packet %02x (%d bytes)\n", type, len);
if (conn->bgp->p.mrtdump & MD_MESSAGES)
bgp_dump_message(conn, pkt, len);
switch (type)
{
case PKT_OPEN: return bgp_rx_open(conn, pkt, len);
case PKT_UPDATE: return bgp_rx_update(conn, pkt, len);
case PKT_NOTIFICATION: return bgp_rx_notification(conn, pkt, len);
case PKT_KEEPALIVE: return bgp_rx_keepalive(conn);
case PKT_ROUTE_REFRESH: return bgp_rx_route_refresh(conn, pkt, len);
default: bgp_error(conn, 1, 3, pkt+18, 1);
}
}
/**
* bgp_rx - handle received data
* @sk: socket
* @size: amount of data received
*
* bgp_rx() is called by the socket layer whenever new data arrive from
* the underlying TCP connection. It assembles the data fragments to packets,
* checks their headers and framing and passes complete packets to
* bgp_rx_packet().
*/
int
bgp_rx(sock *sk, uint size)
{
struct bgp_conn *conn = sk->data;
struct bgp_proto *p = conn->bgp;
byte *pkt_start = sk->rbuf;
byte *end = pkt_start + size;
unsigned i, len;
DBG("BGP: RX hook: Got %d bytes\n", size);
while (end >= pkt_start + BGP_HEADER_LENGTH)
{
if ((conn->state == BS_CLOSE) || (conn->sk != sk))
return 0;
for(i=0; i<16; i++)
if (pkt_start[i] != 0xff)
{
bgp_error(conn, 1, 1, NULL, 0);
break;
}
len = get_u16(pkt_start+16);
if (len < BGP_HEADER_LENGTH || len > bgp_max_packet_length(p))
{
bgp_error(conn, 1, 2, pkt_start+16, 2);
break;
}
if (end < pkt_start + len)
break;
bgp_rx_packet(conn, pkt_start, len);
pkt_start += len;
}
if (pkt_start != sk->rbuf)
{
memmove(sk->rbuf, pkt_start, end - pkt_start);
sk->rpos = sk->rbuf + (end - pkt_start);
}
return 0;
}
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