def _calculate_update(self, ifaces):
"""
Calculates the iptables update to rewrite our chains.
To avoid traversing lots of dispatch rules to find the right one,
we build a tree of chains. Currently, the tree can only be
two layers deep: a root chain and a layer of leaves.
Interface names look like this: "prefix1234abc". The "prefix"
part is always the same so we ignore it. We call "1234abc", the
"suffix".
The root chain contains two sorts of rules:
* where there are multiple interfaces whose suffixes start with
the same character, it contains a rule that matches on
that prefix of the "suffix"(!) and directs the packet to a
leaf chain for that prefix.
* as an optimization, if there is only one interface whose
suffix starts with a given character, it contains a dispatch
rule for that exact interface name.
For example, if we have interface names "tapA1" "tapB1" "tapB2",
we'll get (in pseudo code):
Root chain:
if interface=="tapA1" then goto chain for endpoint tapA1
if interface.startswith("tapB") then goto leaf chain for prefix "tapB"
tapB leaf chain:
if interface=="tapB1" then goto chain for endpoint tapB1
if interface=="tapB2" then goto chain for endpoint tapB2
:param set[str] ifaces: The list of interfaces to generate a
dispatch chain for.
:returns Tuple: to_delete, deps, updates, new_leaf_chains:
* set of leaf chains that are no longer needed for deletion
* chain dependency dict.
* chain updates dict.
* complete set of leaf chains that are now required.
"""
# iptables update fragments/dependencies for the root chains.
updates = defaultdict(list)
root_to_upds = updates[self.chain_to_root]
root_from_upds = updates[self.chain_from_root]
dependencies = defaultdict(set)
root_to_deps = dependencies[self.chain_to_root]
root_from_deps = dependencies[self.chain_from_root]
# Separate the interface names by their prefixes so we can count them
# and decide whether to program a leaf chain or not.
interfaces_by_prefix = defaultdict(set)
iface_prefix = find_longest_prefix(ifaces)
for iface in ifaces:
ep_suffix = iface[len(iface_prefix):]
prefix = ep_suffix[:1]
interfaces_by_prefix[prefix].add(iface)
# Spin through the interfaces by prefix. Either add them directly
# to the root chain or create a leaf and add them there.
new_leaf_chains = set()
for prefix, interfaces in interfaces_by_prefix.iteritems():
use_root_chain = len(interfaces) == 1
if use_root_chain:
# Optimization: there's only one interface with this prefix,
# don't program a leaf chain.
disp_to_chain = self.chain_to_root
disp_from_chain = self.chain_from_root
to_deps = root_to_deps
from_deps = root_from_deps
to_upds = root_to_upds
from_upds = root_from_upds
else:
# There's more than one interface with this prefix, program
# a leaf chain.
disp_to_chain = self.chain_to_leaf + "-" + prefix
disp_from_chain = self.chain_from_leaf + "-" + prefix
to_upds = updates[disp_to_chain]
from_upds = updates[disp_from_chain]
to_deps = dependencies[disp_to_chain]
from_deps = dependencies[disp_from_chain]
new_leaf_chains.add(disp_from_chain)
new_leaf_chains.add(disp_to_chain)
# Root chain depends on its leaves.
root_from_deps.add(disp_to_chain)
root_to_deps.add(disp_from_chain)
# Point root chain at prefix chain.
iface_match = iface_prefix + prefix + "+"
root_from_upds.append(
"--append %s --in-interface %s --goto %s" %
(self.chain_from_root, iface_match, disp_from_chain)
)
root_to_upds.append(
"--append %s --out-interface %s --goto %s" %
(self.chain_to_root, iface_match, disp_to_chain)
)
# Common processing, add the per-endpoint rules to whichever
# chain we decided above.
for iface in interfaces:
# Add rule to leaf or global chain to direct traffic to the
# endpoint-specific one. Note that we use --goto, which means
# that the endpoint-specific chain will return to our parent
# rather than to this chain.
ep_suffix = interface_to_chain_suffix(self.config, iface)
to_chain_name = CHAIN_TO_PREFIX + ep_suffix
from_chain_name = CHAIN_FROM_PREFIX + ep_suffix
from_upds.append("--append %s --in-interface %s --goto %s" %
(disp_from_chain, iface, from_chain_name))
from_deps.add(from_chain_name)
to_upds.append("--append %s --out-interface %s --goto %s" %
(disp_to_chain, iface, to_chain_name))
to_deps.add(to_chain_name)
if not use_root_chain:
# Add a default drop to the end of the leaf chain.
# Add a default drop to the end of the leaf chain.
from_upds.extend(
self.end_of_chain_rules(disp_from_chain, "From"))
to_upds.extend(
self.end_of_chain_rules(disp_to_chain, "To"))
# Both TO and FROM chains end with a DROP so that interfaces that
# we don't know about yet can't bypass our rules.
root_from_upds.extend(
self.end_of_chain_rules(self.chain_from_root, "From"))
root_to_upds.extend(
self.end_of_chain_rules(self.chain_to_root, "To"))
chains_to_delete = self.programmed_leaf_chains - new_leaf_chains
_log.debug("New chains: %s; to delete: %s",
new_leaf_chains, chains_to_delete)
return chains_to_delete, dependencies, updates, new_leaf_chains
def _apply_endpoint_update(self):
pending_endpoint = self._pending_endpoint
if pending_endpoint == self.endpoint:
_log.debug("Endpoint hasn't changed, nothing to do")
return
# Calculate the set of IPs that we had before this update. Needed on
# the update and delete code paths below.
if self.endpoint:
old_ips = set(futils.net_to_ip(n) for n in
self.endpoint.get(self.nets_key, []))
old_nat_mappings = self.endpoint.get(self.nat_key, [])
else:
old_ips = set()
old_nat_mappings = []
all_old_ips = old_ips | set([n["ext_ip"] for n in old_nat_mappings])
if pending_endpoint:
# Update/create.
if pending_endpoint['mac'] != self._mac:
# Either we have not seen this MAC before, or it has changed.
_log.debug("Endpoint MAC changed to %s",
pending_endpoint["mac"])
self._mac = pending_endpoint['mac']
self._mac_changed = True
# MAC change requires refresh of iptables rules and ARP table.
self._iptables_in_sync = False
self._device_in_sync = False
if self.endpoint is None:
# This is the first time we have seen the endpoint, so extract
# the interface name and endpoint ID.
self._iface_name = pending_endpoint["name"]
self._suffix = interface_to_chain_suffix(self.config,
self._iface_name)
_log.debug("Learned interface name/suffix: %s/%s",
self._iface_name, self._suffix)
# First time through, need to program everything.
self._iptables_in_sync = False
self._device_in_sync = False
if self._device_is_up is None:
_log.debug("Learned interface name, checking if device "
"is up.")
self._device_is_up = (
devices.interface_exists(self._iface_name) and
devices.interface_up(self._iface_name)
)
# Check if the profile ID or IP addresses have changed, requiring
# a refresh of the dataplane.
profile_ids = set(pending_endpoint.get("profile_ids", []))
if profile_ids != self._explicit_profile_ids:
# Profile ID update requires iptables update but not device
# update.
_log.debug("Profile IDs changed from %s to %s, need to update "
"iptables", self._rules_ref_helper.required_refs,
profile_ids)
self._explicit_profile_ids = profile_ids
self._iptables_in_sync = False
self._profile_ids_dirty = True
# Check for changes to values that require a device update.
if self.endpoint:
if self.endpoint.get("state") != pending_endpoint.get("state"):
_log.debug("Desired interface state updated.")
self._device_in_sync = False
self._iptables_in_sync = False
new_ips = set(futils.net_to_ip(n) for n in
pending_endpoint.get(self.nets_key, []))
if old_ips != new_ips:
# IP addresses have changed, need to update the routing
# table.
_log.debug("IP addresses changed, need to update routing")
self._device_in_sync = False
new_nat_mappings = pending_endpoint.get(self.nat_key, [])
if old_nat_mappings != new_nat_mappings:
_log.debug("NAT mappings have changed, refreshing.")
self._device_in_sync = False
self._iptables_in_sync = False
all_new_ips = new_ips | set([n["ext_ip"] for n in
new_nat_mappings])
if all_old_ips != all_new_ips:
# Ensure we clean up any conntrack entries for IPs that
# have been removed.
_log.debug("Set of all IPs changed from %s to %s",
all_old_ips, all_new_ips)
self._removed_ips |= all_old_ips
self._removed_ips -= all_new_ips
else:
# Delete of the endpoint. Need to resync everything.
self._profile_ids_dirty = True
self._iptables_in_sync = False
self._device_in_sync = False
self._removed_ips |= all_old_ips
self.endpoint = pending_endpoint
self._endpoint_update_pending = False
self._pending_endpoint = None
def _apply_endpoint_update(self):
pending_endpoint = self._pending_endpoint
if pending_endpoint == self.endpoint:
_log.debug("Endpoint hasn't changed, nothing to do")
return
# Calculate the set of IPs that we had before this update. Needed on
# the update and delete code paths below.
if self.endpoint:
old_ips = set(
futils.net_to_ip(n)
for n in self.endpoint.get(self.nets_key, []))
old_nat_mappings = self.endpoint.get(self.nat_key, [])
else:
old_ips = set()
old_nat_mappings = []
all_old_ips = old_ips | set([n["ext_ip"] for n in old_nat_mappings])
if pending_endpoint:
# Update/create.
if pending_endpoint.get('mac') != self._mac:
# Either we have not seen this MAC before, or it has changed.
_log.debug("Endpoint MAC changed to %s",
pending_endpoint.get("mac"))
self._mac = pending_endpoint.get('mac')
self._mac_changed = True
# MAC change requires refresh of iptables rules and ARP table.
self._iptables_in_sync = False
self._device_in_sync = False
new_iface_name = pending_endpoint["name"]
# Interface renames are handled in the EndpointManager by
# simulating a delete then an add. We shouldn't see one here.
assert (self.endpoint is None
or self._iface_name == new_iface_name), (
"Unexpected change of interface name.")
if self.endpoint is None:
# This is the first time we have seen the endpoint, so extract
# the interface name and endpoint ID.
self._iface_name = new_iface_name
self._suffix = interface_to_chain_suffix(
self.config, self._iface_name)
_log.debug("Learned interface name/suffix: %s/%s",
self._iface_name, self._suffix)
# First time through, need to program everything.
self._iptables_in_sync = False
self._device_in_sync = False
if self._device_is_up is None:
_log.debug("Learned interface name, checking if device "
"is up.")
self._device_is_up = (
devices.interface_exists(self._iface_name)
and devices.interface_up(self._iface_name))
# Check if the profile ID or IP addresses have changed, requiring
# a refresh of the dataplane.
profile_ids = set(pending_endpoint.get("profile_ids", []))
if profile_ids != self._explicit_profile_ids:
# Profile ID update requires iptables update but not device
# update.
_log.debug(
"Profile IDs changed from %s to %s, need to update "
"iptables", self._rules_ref_helper.required_refs,
profile_ids)
self._explicit_profile_ids = profile_ids
self._iptables_in_sync = False
self._profile_ids_dirty = True
# Check for changes to values that require a device update.
if self.endpoint:
if self.endpoint.get("state") != pending_endpoint.get("state"):
_log.debug("Desired interface state updated.")
self._device_in_sync = False
self._iptables_in_sync = False
new_ips = set(
futils.net_to_ip(n)
for n in pending_endpoint.get(self.nets_key, []))
if old_ips != new_ips:
# IP addresses have changed, need to update the routing
# table.
_log.debug("IP addresses changed, need to update routing")
self._device_in_sync = False
new_nat_mappings = pending_endpoint.get(self.nat_key, [])
if old_nat_mappings != new_nat_mappings:
_log.debug("NAT mappings have changed, refreshing.")
self._device_in_sync = False
self._iptables_in_sync = False
all_new_ips = new_ips | set(
[n["ext_ip"] for n in new_nat_mappings])
if all_old_ips != all_new_ips:
# Ensure we clean up any conntrack entries for IPs that
# have been removed.
_log.debug("Set of all IPs changed from %s to %s",
all_old_ips, all_new_ips)
self._removed_ips |= all_old_ips
self._removed_ips -= all_new_ips
else:
# Delete of the endpoint. Need to resync everything.
self._profile_ids_dirty = True
self._iptables_in_sync = False
self._device_in_sync = False
self._removed_ips |= all_old_ips
self.endpoint = pending_endpoint
self._endpoint_update_pending = False
self._pending_endpoint = None
def _calculate_update(self, ifaces):
"""
Calculates the iptables update to rewrite our chains.
To avoid traversing lots of dispatch rules to find the right one,
we build a tree of chains. Currently, the tree can only be
two layers deep: a root chain and a layer of leaves.
Interface names look like this: "prefix1234abc". The "prefix"
part is always the same so we ignore it. We call "1234abc", the
"suffix".
The root chain contains two sorts of rules:
* where there are multiple interfaces whose suffixes start with
the same character, it contains a rule that matches on
that prefix of the "suffix"(!) and directs the packet to a
leaf chain for that prefix.
* as an optimization, if there is only one interface whose
suffix starts with a given character, it contains a dispatch
rule for that exact interface name.
For example, if we have interface names "tapA1" "tapB1" "tapB2",
we'll get (in pseudo code):
Root chain:
if interface=="tapA1" then goto chain for endpoint tapA1
if interface.startswith("tapB") then goto leaf chain for prefix "tapB"
tapB leaf chain:
if interface=="tapB1" then goto chain for endpoint tapB1
if interface=="tapB2" then goto chain for endpoint tapB2
:param set[str] ifaces: The list of interfaces to generate a
dispatch chain for.
:returns Tuple: to_delete, deps, updates, new_leaf_chains:
* set of leaf chains that are no longer needed for deletion
* chain dependency dict.
* chain updates dict.
* complete set of leaf chains that are now required.
"""
# iptables update fragments/dependencies for the root chains.
updates = defaultdict(list)
root_to_upds = updates[self.chain_to_root]
root_from_upds = updates[self.chain_from_root]
dependencies = defaultdict(set)
root_to_deps = dependencies[self.chain_to_root]
root_from_deps = dependencies[self.chain_from_root]
# Separate the interface names by their prefixes so we can count them
# and decide whether to program a leaf chain or not.
interfaces_by_prefix = defaultdict(set)
iface_prefix = find_longest_prefix(ifaces)
for iface in ifaces:
ep_suffix = iface[len(iface_prefix):]
prefix = ep_suffix[:1]
interfaces_by_prefix[prefix].add(iface)
# Spin through the interfaces by prefix. Either add them directly
# to the root chain or create a leaf and add them there.
new_leaf_chains = set()
for prefix, interfaces in interfaces_by_prefix.iteritems():
use_root_chain = len(interfaces) == 1
if use_root_chain:
# Optimization: there's only one interface with this prefix,
# don't program a leaf chain.
disp_to_chain = self.chain_to_root
disp_from_chain = self.chain_from_root
to_deps = root_to_deps
from_deps = root_from_deps
to_upds = root_to_upds
from_upds = root_from_upds
else:
# There's more than one interface with this prefix, program
# a leaf chain.
disp_to_chain = self.chain_to_leaf + "-" + prefix
disp_from_chain = self.chain_from_leaf + "-" + prefix
to_upds = updates[disp_to_chain]
from_upds = updates[disp_from_chain]
to_deps = dependencies[disp_to_chain]
from_deps = dependencies[disp_from_chain]
new_leaf_chains.add(disp_from_chain)
new_leaf_chains.add(disp_to_chain)
# Root chain depends on its leaves.
root_from_deps.add(disp_to_chain)
root_to_deps.add(disp_from_chain)
# Point root chain at prefix chain.
iface_match = iface_prefix + prefix + "+"
root_from_upds.append(
"--append %s --in-interface %s --goto %s" %
(self.chain_from_root, iface_match, disp_from_chain)
)
root_to_upds.append(
"--append %s --out-interface %s --goto %s" %
(self.chain_to_root, iface_match, disp_to_chain)
)
# Common processing, add the per-endpoint rules to whichever
# chain we decided above.
for iface in interfaces:
# Add rule to leaf or global chain to direct traffic to the
# endpoint-specific one. Note that we use --goto, which means
# that the endpoint-specific chain will return to our parent
# rather than to this chain.
ep_suffix = interface_to_chain_suffix(self.config, iface)
to_chain_name = CHAIN_TO_PREFIX + ep_suffix
from_chain_name = CHAIN_FROM_PREFIX + ep_suffix
from_upds.append("--append %s --in-interface %s --goto %s" %
(disp_from_chain, iface, from_chain_name))
from_deps.add(from_chain_name)
to_upds.append("--append %s --out-interface %s --goto %s" %
(disp_to_chain, iface, to_chain_name))
to_deps.add(to_chain_name)
if not use_root_chain:
# Add a default drop to the end of the leaf chain.
# Add a default drop to the end of the leaf chain.
from_upds.extend(
self.end_of_chain_rules(disp_from_chain, "From"))
to_upds.extend(
self.end_of_chain_rules(disp_to_chain, "To"))
# Both TO and FROM chains end with a DROP so that interfaces that
# we don't know about yet can't bypass our rules.
root_from_upds.extend(
self.end_of_chain_rules(self.chain_from_root, "From"))
root_to_upds.extend(
self.end_of_chain_rules(self.chain_to_root, "To"))
chains_to_delete = self.programmed_leaf_chains - new_leaf_chains
_log.debug("New chains: %s; to delete: %s",
new_leaf_chains, chains_to_delete)
return chains_to_delete, dependencies, updates, new_leaf_chains
