def build_ospf(anm):
"""
Build OSPF graph.
Allowable area combinations:
0 -> 0
0 -> x (x!= 0)
x -> 0 (x!= 0)
x -> x (x != 0)
Not-allowed:
x -> x (x != y != 0)
#TODO: build check that verifies these rules
"""
import netaddr
g_in = anm['input']
# add regardless, so allows quick check of node in anm['ospf'] in compilers
g_ospf = anm.add_overlay("ospf")
if not any(n.igp == "ospf" for n in g_in):
log.debug("No OSPF nodes")
return
g_ospf.add_nodes_from(g_in.nodes("is_router", igp="ospf"), retain=['asn'])
g_ospf.add_nodes_from(g_in.nodes("is_switch"), retain=['asn'])
g_ospf.add_edges_from(g_in.edges(), retain=['edge_id'])
ank_utils.copy_attr_from(g_in, g_ospf, "ospf_area", dst_attr="area")
ank_utils.copy_edge_attr_from(g_in,
g_ospf,
"ospf_cost",
dst_attr="cost",
type=float)
ank_utils.aggregate_nodes(g_ospf,
g_ospf.nodes("is_switch"),
retain="edge_id")
exploded_edges = ank_utils.explode_nodes(g_ospf,
g_ospf.nodes("is_switch"),
retain="edge_id")
for edge in exploded_edges:
edge.multipoint = True
g_ospf.remove_edges_from([
link for link in g_ospf.edges() if link.src.asn != link.dst.asn
]) # remove inter-AS links
area_zero_ip = netaddr.IPAddress("0.0.0.0")
area_zero_int = 0
area_zero_ids = {area_zero_ip, area_zero_int}
default_area = area_zero_int
if any(router.area == "0.0.0.0" for router in g_ospf):
# string comparison as hasn't yet been cast to IPAddress
default_area = area_zero_ip
for router in g_ospf:
if not router.area or router.area == "None":
router.area = default_area
# check if 0.0.0.0 used anywhere, if so then use 0.0.0.0 as format
else:
try:
router.area = int(router.area)
except ValueError:
try:
router.area = netaddr.IPAddress(router.area)
except netaddr.core.AddrFormatError:
log.warning("Invalid OSPF area %s for %s. Using default"
" of %s" % (router.area, router, default_area))
router.area = default_area
for router in g_ospf:
# and set area on interface
for edge in router.edges():
if edge.area:
continue # allocated (from other "direction", as undirected)
if router.area == edge.dst.area:
edge.area = router.area # intra-area
continue
if router.area in area_zero_ids or edge.dst.area in area_zero_ids:
# backbone to other area
if router.area in area_zero_ids:
# router in backbone, use other area
edge.area = edge.dst.area
else:
# router not in backbone, use its area
edge.area = router.area
for router in g_ospf:
areas = {edge.area for edge in router.edges()}
router.areas = list(areas) # edges router participates in
if len(areas) in area_zero_ids:
router.type = "backbone" # no ospf edges (eg single node in AS)
elif len(areas) == 1:
# single area: either backbone (all 0) or internal (all nonzero)
if len(areas & area_zero_ids):
# intersection has at least one element -> router has area zero
router.type = "backbone"
else:
router.type = "internal"
else:
# multiple areas
if len(areas & area_zero_ids):
# intersection has at least one element -> router has area zero
router.type = "backbone ABR"
else:
log.warning(
"%s spans multiple areas but is not a member of area 0" %
router)
router.type = "INVALID"
if (any(area_zero_int in router.areas for router in g_ospf)
and any(area_zero_ip in router.areas for router in g_ospf)):
log.warning("Using both area 0 and area 0.0.0.0")
for link in g_ospf.edges():
if not link.cost:
link.cost = 1
# map areas and costs onto interfaces
#TODO: later map them directly rather than with edges - this is part of the transition
for edge in g_ospf.edges():
for interface in edge.interfaces():
interface.cost = edge.cost
interface.area = edge.area
interface.multipoint = edge.multipoint
for router in g_ospf:
router.loopback_zero.area = router.area
router.loopback_zero.cost = 0
def build_ospf(anm):
"""
Build OSPF graph.
Allowable area combinations:
0 -> 0
0 -> x (x!= 0)
x -> 0 (x!= 0)
x -> x (x != 0)
Not-allowed:
x -> x (x != y != 0)
#TODO: build check that verifies these rules
"""
import netaddr
g_in = anm['input']
# add regardless, so allows quick check of node in anm['ospf'] in compilers
g_ospf = anm.add_overlay("ospf")
if not any(n.igp == "ospf" for n in g_in):
log.debug("No OSPF nodes")
return
g_ospf.add_nodes_from(g_in.nodes("is_router", igp = "ospf"), retain=['asn'])
g_ospf.add_nodes_from(g_in.nodes("is_server", igp = "ospf"), retain=['asn'])
g_ospf.add_nodes_from(g_in.nodes("is_switch"), retain=['asn'])
g_ospf.add_edges_from(g_in.edges(), retain=['edge_id'])
ank_utils.copy_attr_from(g_in, g_ospf, "ospf_area", dst_attr="area")
ank_utils.copy_edge_attr_from(g_in, g_ospf, "ospf_cost", dst_attr="cost", type=float)
ank_utils.aggregate_nodes(g_ospf, g_ospf.nodes("is_switch"),
retain="edge_id")
exploded_edges = ank_utils.explode_nodes(g_ospf, g_ospf.nodes("is_switch"),
retain="edge_id")
for edge in exploded_edges:
edge.multipoint = True
g_ospf.remove_edges_from([link for link in g_ospf.edges(
) if link.src.asn != link.dst.asn]) # remove inter-AS links
area_zero_ip = netaddr.IPAddress("0.0.0.0")
area_zero_int = 0
area_zero_ids = {area_zero_ip, area_zero_int}
default_area = area_zero_int
if any(router.area == "0.0.0.0" for router in g_ospf):
# string comparison as hasn't yet been cast to IPAddress
default_area = area_zero_ip
#TODO: use interfaces throughout, rather than edges
for router in g_ospf:
if not router.area or router.area == "None":
router.area = default_area
# check if 0.0.0.0 used anywhere, if so then use 0.0.0.0 as format
else:
try:
router.area = int(router.area)
except ValueError:
try:
router.area = netaddr.IPAddress(router.area)
except netaddr.core.AddrFormatError:
log.warning("Invalid OSPF area %s for %s. Using default"
" of %s" % (router.area, router, default_area))
router.area = default_area
for router in g_ospf:
# and set area on interface
for edge in router.edges():
if edge.area:
continue # allocated (from other "direction", as undirected)
if router.area == edge.dst.area:
edge.area = router.area # intra-area
continue
if router.area in area_zero_ids or edge.dst.area in area_zero_ids:
# backbone to other area
if router.area in area_zero_ids:
# router in backbone, use other area
edge.area = edge.dst.area
else:
# router not in backbone, use its area
edge.area = router.area
for router in g_ospf:
areas = {edge.area for edge in router.edges()}
router.areas = list(areas) # edges router participates in
if len(areas) in area_zero_ids:
router.type = "backbone" # no ospf edges (eg single node in AS)
elif len(areas) == 1:
# single area: either backbone (all 0) or internal (all nonzero)
if len(areas & area_zero_ids):
# intersection has at least one element -> router has area zero
router.type = "backbone"
else:
router.type = "internal"
else:
# multiple areas
if len(areas & area_zero_ids):
# intersection has at least one element -> router has area zero
router.type = "backbone ABR"
else:
log.warning(
"%s spans multiple areas but is not a member of area 0"
% router)
router.type = "INVALID"
if (any(area_zero_int in router.areas for router in g_ospf) and
any(area_zero_ip in router.areas for router in g_ospf)):
log.warning("Using both area 0 and area 0.0.0.0")
for link in g_ospf.edges():
if not link.cost:
link.cost = 1
# map areas and costs onto interfaces
#TODO: later map them directly rather than with edges - this is part of the transition
for edge in g_ospf.edges():
for interface in edge.interfaces():
interface.cost = edge.cost
interface.area = edge.area
interface.multipoint = edge.multipoint
for router in g_ospf:
router.loopback_zero.area = router.area
router.loopback_zero.cost = 0
