Implements option that controls IPv6 BGP next hops when lladdr is missing.
This commit is contained in:
Ondrej Zajicek
parent
62aa96caa2
commit
3f9b7bfe9f
6 changed files with 69 additions and 23 deletions
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@ -646,7 +646,7 @@ incompatible with each other (that is to prevent you from shooting in the foot).
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but <cf>1.0.0.0/16 ˜ [ 1.0.0.0/8- ]</cf> is false.
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Cisco-style patterns like <cf>10.0.0.0/8 ge 16 le 24</cf> can be expressed
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in Bird as <cf>10.0.0.0/8{16,24}</cf>, <cf>192.168.0.0/16 le 24</cf> as
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in BIRD as <cf>10.0.0.0/8{16,24}</cf>, <cf>192.168.0.0/16 le 24</cf> as
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<cf>192.168.0.0/16{16,24}</cf> and <cf>192.168.0.0/16 ge 24</cf> as
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<cf>192.168.0.0/16{24,32}</cf>.
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@ -887,12 +887,28 @@ for each neighbor using the following configuration parameters:
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we should route via our direct neighbor with address <m/ip/.
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Default: switched off.
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<tag>next hop self</tag> Avoid calculation of the Next Hop attribute
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and always advertise our own source address (see below) as a next hop.
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This needs to be used only
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occasionally to circumvent misconfigurations of other routers.
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<tag>next hop self</tag> Avoid calculation of the Next Hop
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attribute and always advertise our own source address (see
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below) as a next hop. This needs to be used only occasionally
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to circumvent misconfigurations of other routers.
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Default: disabled.
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<tag>missing lladdr self|drop|ignore</tag>Next Hop attribute
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in BGP-IPv6 sometimes contains just the global IPv6 address,
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but sometimes it has to contain both global and link-local
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IPv6 addresses. This option specifies what to do if BIRD have
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to send both addresses but does not know link-local address.
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This situation might happen when routes from other protocols
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are exported to BGP, or when improper updates are received
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from BGP peers. <tag/self/ means that BIRD advertises its own
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local address instead. <tag/drop/ means that BIRD skips that
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prefixes and logs error. <tag/ignore/ means that BIRD ignores
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the problem and sends just the global address (and therefore
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forms improper BGP update). Default: <tag/self/, unless BIRD
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is configured as a route server (option <tag/rs client/), in
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that case default is <tag/drop/, because route servers usually
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does not forward packets ifselves.
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<tag>source address <m/ip/</tag> Define local address we should use
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for next hop calculation. Default: the address of the local end
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of the interface our neighbor is connected to.
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@ -920,7 +936,7 @@ for each neighbor using the following configuration parameters:
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as a route server client. A route server is used as a
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replacement for full mesh EBGP routing in Internet exchange
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points in a similar way to route reflectors used in IBGP routing.
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Bird does not implement obsoleted RFC 1863, but uses ad-hoc implementation,
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BIRD does not implement obsoleted RFC 1863, but uses ad-hoc implementation,
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which behaves like plain EBGP but reduces modifications to advertised route
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attributes to be transparent (for example does not prepend its AS number to
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AS PATH attribute and keep MED attribute). Default: disabled.
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@ -141,7 +141,7 @@ proto_item:
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| EXPORT imexport { this_proto->out_filter = $2; }
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| TABLE rtable { this_proto->table = $2; }
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| ROUTER ID idval { this_proto->router_id = $3; }
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| DESCRIPTION dsc { this_proto->dsc = $2; }
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| DESCRIPTION TEXT { this_proto->dsc = $2; }
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;
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imexport:
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@ -886,6 +886,10 @@ bgp_check(struct bgp_config *c)
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if ((c->local_as == c->remote_as) && (c->rs_client))
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cf_error("Only external neighbor can be RS client");
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/* Different default based on rs_client */
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if (c->missing_lladdr == 0)
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c->missing_lladdr = c->rs_client ? MLL_DROP : MLL_SELF;
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}
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static char *bgp_state_names[] = { "Idle", "Connect", "Active", "OpenSent", "OpenConfirm", "Established", "Close" };
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@ -23,6 +23,7 @@ struct bgp_config {
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ip_addr multihop_via; /* Multihop: address to route to */
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ip_addr source_addr; /* Source address to use */
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int next_hop_self; /* Always set next hop to local IP address */
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int missing_lladdr; /* What we will do when we don' know link-local addr, see MLL_* */
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int compare_path_lengths; /* Use path lengths when selecting best route */
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int prefer_older; /* Prefer older routes according to RFC 5004 */
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u32 default_local_pref; /* Default value for LOCAL_PREF attribute */
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@ -46,6 +47,10 @@ struct bgp_config {
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char *password; /* Password used for MD5 authentication */
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};
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#define MLL_SELF 1
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#define MLL_DROP 2
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#define MLL_IGNORE 3
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struct bgp_conn {
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struct bgp_proto *bgp;
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struct birdsock *sk;
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@ -22,7 +22,8 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
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BGP_PATH, BGP_LOCAL_PREF, BGP_MED, BGP_ORIGIN, BGP_NEXT_HOP,
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BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS,
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PASSWORD, RR, RS, CLIENT, CLUSTER, ID, AS4, ADVERTISE, IPV4,
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CAPABILITIES, LIMIT, PASSIVE, PREFER, OLDER)
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CAPABILITIES, LIMIT, PASSIVE, PREFER, OLDER, MISSING, LLADDR,
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DROP, IGNORE)
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CF_GRAMMAR
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@ -64,6 +65,9 @@ bgp_proto:
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| bgp_proto KEEPALIVE TIME expr ';' { BGP_CFG->keepalive_time = $4; }
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| bgp_proto MULTIHOP expr VIA ipa ';' { BGP_CFG->multihop = $3; BGP_CFG->multihop_via = $5; }
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| bgp_proto NEXT HOP SELF ';' { BGP_CFG->next_hop_self = 1; }
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| bgp_proto MISSING LLADDR SELF ';' { BGP_CFG->missing_lladdr = MLL_SELF; }
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| bgp_proto MISSING LLADDR DROP ';' { BGP_CFG->missing_lladdr = MLL_DROP; }
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| bgp_proto MISSING LLADDR IGNORE ';' { BGP_CFG->missing_lladdr = MLL_IGNORE; }
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| bgp_proto PATH METRIC bool ';' { BGP_CFG->compare_path_lengths = $4; }
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| bgp_proto PREFER OLDER bool ';' { BGP_CFG->prefer_older = $4; }
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| bgp_proto DEFAULT BGP_MED expr ';' { BGP_CFG->default_med = $4; }
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@ -199,7 +199,7 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
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if (a_size < 0)
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{
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log(L_ERR "%s: Attribute list too long, skipping corresponding route group", p->p.name);
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log(L_ERR "%s: Attribute list too long, skipping corresponding routes", p->p.name);
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bgp_flush_prefixes(p, buck);
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rem_node(&buck->send_node);
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bgp_free_bucket(p, buck);
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@ -234,9 +234,9 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
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{
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struct bgp_proto *p = conn->bgp;
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struct bgp_bucket *buck;
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int size, second;
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int size, second, rem_stored;
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int remains = BGP_MAX_PACKET_LENGTH - BGP_HEADER_LENGTH - 4;
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byte *w, *tmp, *tstart;
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byte *w, *w_stored, *tmp, *tstart;
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ip_addr *ipp, ip, ip_ll;
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ea_list *ea;
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eattr *nh;
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@ -272,28 +272,25 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
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}
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DBG("Processing bucket %p\n", buck);
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size = bgp_encode_attrs(p, w, buck->eattrs, 2048);
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rem_stored = remains;
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w_stored = w;
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size = bgp_encode_attrs(p, w, buck->eattrs, 2048);
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if (size < 0)
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{
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log(L_ERR "%s: Attribute list too long, ignoring corresponding route group", p->p.name);
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log(L_ERR "%s: Attribute list too long, skipping corresponding routes", p->p.name);
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bgp_flush_prefixes(p, buck);
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rem_node(&buck->send_node);
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bgp_free_bucket(p, buck);
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continue;
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}
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w += size;
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remains -= size;
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tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
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*tmp++ = 0;
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*tmp++ = BGP_AF_IPV6;
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*tmp++ = 1;
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/* We have two addresses here in NEXT_HOP eattr. Really.
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Unless NEXT_HOP was modified by filter */
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nh = ea_find(buck->eattrs, EA_CODE(EAP_BGP, BA_NEXT_HOP));
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ASSERT(nh);
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/* We have two addresses here in 'nh'. Really.
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Unless NEXT_HOP was modified by filter */
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second = (nh->u.ptr->length == NEXT_HOP_LENGTH);
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ipp = (ip_addr *) nh->u.ptr->data;
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ip = ipp[0];
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@ -322,12 +319,32 @@ bgp_create_update(struct bgp_conn *conn, byte *buf)
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ip_ll = ipp[1];
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else
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{
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ip = p->source_addr;
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ip_ll = p->local_link;
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switch (p->cf->missing_lladdr)
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{
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case MLL_SELF:
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ip = p->source_addr;
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ip_ll = p->local_link;
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break;
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case MLL_DROP:
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log(L_ERR "%s: Missing link-local next hop address, skipping corresponding routes", p->p.name);
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w = w_stored;
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remains = rem_stored;
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bgp_flush_prefixes(p, buck);
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rem_node(&buck->send_node);
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bgp_free_bucket(p, buck);
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continue;
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case MLL_IGNORE:
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break;
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}
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}
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}
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}
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tstart = tmp = bgp_attach_attr_wa(&ea, bgp_linpool, BA_MP_REACH_NLRI, remains-8);
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*tmp++ = 0;
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*tmp++ = BGP_AF_IPV6;
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*tmp++ = 1;
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if (ipa_nonzero(ip_ll))
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{
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*tmp++ = 32;
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