Class: OsCtld::NetConfig

Inherits:
Object
  • Object
show all
Defined in:
lib/osctld/net_config.rb

Overview

Generate network configuration for a container and apply using netlink

NetConfig has to be created before switching to container user and attaching to the container. Call NetConfig.create while running as root and #setup while attached into a container.

Defined Under Namespace

Classes: Addr, NetIf, Route

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ NetConfig

Returns a new instance of NetConfig.



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# File 'lib/osctld/net_config.rb', line 32

def initialize
  @netifs = []
end

Instance Attribute Details

#netifs ⇒ Object (readonly)

Returns the value of attribute netifs.



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# File 'lib/osctld/net_config.rb', line 17

def netifs
  @netifs
end

Class Method Details

.create(ct) ⇒ Object

Parameters:



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# File 'lib/osctld/net_config.rb', line 20

def self.create(ct)
  cfg = new
  ct.netifs.each { |netif| cfg.add_netif(netif) }
  cfg
end

.import(data) ⇒ Object 



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# File 'lib/osctld/net_config.rb', line 26

def self.import(data)
  cfg = new
  cfg.import(data)
  cfg
end

Instance Method Details

#add_netif(netif) ⇒ Object

Parameters:



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# File 'lib/osctld/net_config.rb', line 37

def add_netif(netif)
  n = NetIf.new(netif.name, [], [])

  [4, 6].each do |ip_v|
    if netif.respond_to?(:ips)
      netif.ips(ip_v).each do |ip|
        n.ips << Addr.new(ip_v, ip.to_s, ip.prefix.to_i)
      end
    end

    case netif.type
    when :bridge
      if netif.has_gateway?(ip_v)
        n.routes << Route.new(ip_v, default_route_addr(ip_v), 0, netif.gateway(ip_v))
      end

    when :routed
      # An IPv6-only interface cannot supply an IPv4 gateway/source, and
      # vice versa. Do not install defaults for unconfigured families.
      next unless n.ips.any? { |ip| ip.version == ip_v }

      begin
        via = netif.default_via(ip_v).to_s
        n.routes << Route.new(ip_v, via, ip_v == 4 ? 32 : 128, nil)
        n.routes << Route.new(ip_v, default_route_addr(ip_v), 0, via)
      rescue RuntimeError
        # IPv6 is routed via link-local address on the host interface, which
        # is not known when the container is stopped.
        next if ip_v == 6
      end
    end
  end

  netifs << n
end

#default_route_addr(ip_v) ⇒ Object (protected) 



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# File 'lib/osctld/net_config.rb', line 184

def default_route_addr(ip_v)
  ip_v == 4 ? '0.0.0.0' : '::'
end

#export ⇒ Object 



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# File 'lib/osctld/net_config.rb', line 100

def export
  netifs.map do |netif|
    {
      name: netif.name,
      ips: netif.ips.map(&:to_h),
      routes: netif.routes.map(&:to_h)
    }
  end
end

#import(data) ⇒ Object 



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# File 'lib/osctld/net_config.rb', line 110

def import(data)
  data.each do |netif_hash|
    netifs << NetIf.new(
      netif_hash[:name],
      netif_hash[:ips].map do |v|
        Addr.new(v[:version], v[:address], v[:prefix])
      end,
      netif_hash[:routes].map do |v|
        Route.new(v[:version], v[:address], v[:prefix], v[:via])
      end
    )
  end
end

#setup ⇒ Object

Apply configuration using netlink



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# File 'lib/osctld/net_config.rb', line 74

def setup
  nl = Linux::Netlink::Route::Socket.new
  wait_for_netifs(nl)

  netifs.each do |netif|
    netif.ips.each do |ip|
      nl.addr.add(index: netif.name, local: ip.address, prefixlen: ip.prefix)
    rescue Errno::EEXIST
      next
    end

    netif.routes.each do |route|
      nl.route.add(
        oif: netif.name,
        dst: route.address,
        dst_len: route.prefix,
        gateway: route.via
      )
    rescue Errno::EEXIST
      next
    end
  end

  wait_for_ipv6_addresses(nl)
end

#wait_for_ipv6_addresses(nl, timeout: 10) ⇒ Object (protected) 



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# File 'lib/osctld/net_config.rb', line 126

def wait_for_ipv6_addresses(nl, timeout: 10)
  expected = netifs.flat_map do |netif|
    netif.ips.select { |ip| ip.version == 6 }.map { |ip| [netif.name, IPAddr.new(ip.address)] }
  end
  return if expected.empty?

  deadline = Process.clock_gettime(Process::CLOCK_MONOTONIC) + timeout

  loop do
    # AddrHandler memoizes dumps: DAD progress requires a fresh snapshot.
    nl.addr.clear_cache
    addresses = expected.map(&:first).uniq.to_h do |name|
      [name, nl.addr.list(index: name, family: Socket::AF_INET6).to_a]
    end
    # Neighbor discovery also uses the interface's automatic link-local
    # address, whose DAD can finish after the configured global address.
    link_local = addresses.flat_map do |name, entries|
      entries.select { |entry| entry.address.link_local? }.map { |entry| [name, entry.address] }
    end
    pending = (expected + link_local).uniq.reject do |name, ip|
      address = addresses.fetch(name).find { |entry| entry.address == ip }
      next false unless address

      if address.flags.anybits?(Linux::IFA_F_DADFAILED)
        raise "IPv6 duplicate address detection failed: #{name}=#{ip}"
      end

      address.flags.nobits?(Linux::IFA_F_TENTATIVE)
    end
    return if pending.empty?

    if Process.clock_gettime(Process::CLOCK_MONOTONIC) >= deadline
      raise "IPv6 addresses not ready: #{pending.map { |name, ip| "#{name}=#{ip}" }.join(', ')}"
    end

    sleep(0.1)
  end
end

#wait_for_netifs(nl, timeout: 10) ⇒ Object (protected) 



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# File 'lib/osctld/net_config.rb', line 165

def wait_for_netifs(nl, timeout: 10)
  names = netifs.map(&:name).uniq
  return if names.empty?

  deadline = Time.now + timeout
  missing = []

  loop do
    existing = nl.link.list.map(&:ifname)
    missing = names - existing
    return if missing.empty?
    break if Time.now >= deadline

    sleep(0.1)
  end

  raise "network interfaces not found: #{missing.join(', ')}"
end