fs/skeleton/sbin/dhclient-script

#!/bin/sh
# dhclient-script for Linux. Dan Halbert, March, 1997.
# Updated for Linux 2.[12] by Brian J. Murrell, January 1999.
# No guarantees about this. I'm a novice at the details of Linux
# networking.
# Conversion to use ip for ipv4 (instead of ifconfig, route) by Peter Marschall
# Extended for 4.2.2, and ip output to /dev/null removed, by Ken Moffat

# Notes:

# 0. This script is based on the netbsd script supplied with dhcp-970306.

# 1. ifconfig down apparently deletes all relevant routes and flushes
# the arp cache, so this doesn't need to be done explicitly.

# 2. The alias address handling here has not been tested AT ALL.
# I'm just going by the doc of modern Linux ip aliasing, which uses
# notations like eth0:0, eth0:1, for each alias.

# 3. I have to calculate the network address, and calculate the broadcast
# address if it is not supplied. This might be much more easily done
# by the dhclient C code, and passed on.

# 4. TIMEOUT not tested. ping has a flag I don't know, and I'm suspicious
# of the $1 in its args.

printenv

. /etc/utils.sh

CONMAN_DIR=/tmp/conman
mkdir -p "$CONMAN_DIR"
mkdir -p /tmp/dnsmasq

ip=ip
wifi_ifc=eth2
bridge_ifc=br0

log() {
  echo "$@" >&2
}

log_file_contents() {
  local filename="$1"
  while read line; do
    log "$filename: $line"
  done <$filename
}

routable_ifc() {
  [ "$interface" != "$wifi_ifc" ]
}

is_ipv6() {
  endswith "$reason" "6"
}

internal_resolv_conf="
# Note: these settings are hardcoded so that DHCP-provided settings don't
# conflict with our log uploader and ACS.  For DHCP-provided settings
# suitable for end users, use /tmp/resolv.conf.external instead.
nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844
options single-request-reopen
options timeout:2
options attempts:3
"

merge_resolv_conf() {
    local confs=""

    if [ -e "/tmp/resolv.conf.dhclient" ]; then
        confs="$confs /tmp/resolv.conf.dhclient"
    fi

    if [ -e "/tmp/resolv.conf.dhclient6" ]; then
        confs="$confs /tmp/resolv.conf.dhclient6"
    fi

    if [ -n "$confs" ]; then
        atomic /tmp/resolv.conf.external "$(cat $confs)"
        log_file_contents /tmp/resolv.conf.external
        if [ -e "/config/allowdns" ]; then
            ln -sf /tmp/resolv.conf.external /tmp/resolv.conf
        else
            atomic /tmp/resolv.conf "$internal_resolv_conf"
        fi
        log_file_contents /tmp/resolv.conf
        for conf in /chroot/*/tmp; do
          if [ -d "$conf" ]; then
            atomic "$conf/resolv.conf" "$internal_resolv_conf"
            echo "Updated $conf/resolv.conf"
          fi
        done
    fi
}

make_resolv_conf() {
  if [ -n "$new_domain_name_servers" ]; then
    atomic /tmp/resolv.conf.dhclient "$(
      if [ -n "$new_domain_search" ]; then
        echo search $new_domain_search
        log "dns4 search $new_domain_search"
      elif [ -n "$new_domain_name" ]; then
        # Note that the DHCP 'Domain Name Option' is really just a domain
        # name, and that this practice of using the domain name option as
        # a search path is both nonstandard and deprecated.
        echo search $new_domain_name
        log "dns4 search $new_domain_name"
      fi
      for nameserver in $new_domain_name_servers; do
        echo nameserver $nameserver
        log "dns4 nameserver $nameserver"
      done
    )"
    merge_resolv_conf
  elif [ -n "$new_dhcp6_name_servers" ]; then
    atomic /tmp/resolv.conf.dhclient6 "$(
      if [ -n "$new_dhcp6_domain_search" ]; then
        echo search $new_dhcp6_domain_search
        log "dns6 search $new_dhcp6_domain_search"
      fi
      for nameserver in $new_dhcp6_name_servers; do
        echo nameserver $nameserver
        log "dns6 nameserver $nameserver"
      done
    )"
    merge_resolv_conf
  fi
}

make_dnsmasq_ipv6() {
  local prefix64="$1"
  if [ -n "$prefix64" ]; then
    # Write out a config that will enable dhcpv6 stateless server
    # and send router advertisements every 10 seconds.
    atomic /tmp/dnsmasq/ipv6.conf "$(
      echo "dhcp-range=${prefix64},ra-stateless"
      echo "ra-param=${bridge_ifc},10"
    )"
  else
    rm -f /tmp/dnsmasq/ipv6.conf
  fi
}

make_cwmp_files() {
  if [ -n "$new_cwmp_acs_url" ]; then
    log "cwmp dhcp acs '$new_cwmp_acs_url'"
    if is_ipv6; then
      set-acs dhcp6 "$new_cwmp_acs_url"
    else
      set-acs dhcp "$new_cwmp_acs_url"
    fi
  fi
  if [ -n "$new_cwmp_provisioning_code" ]; then
    atomic /tmp/cwmp/provisioning_code "$new_cwmp_provisioning_code"
    log "cwmp provisioning '$new_cwmp_provisioning_code'"
  fi
  if [ -n "$new_cwmp_retry_minimum_wait_interval" ]; then
    atomic /tmp/cwmp/retry_minimum_wait_interval "$new_cwmp_retry_minimum_wait_interval"
    log "cwmp retry minwait '$new_cwmp_retry_minimum_wait_interval'"
  fi
  if [ -n "$new_cwmp_retry_interval_multiplier" ]; then
    atomic /tmp/cwmp/retry_interval_multiplier "$new_cwmp_retry_interval_multiplier"
    log "cwmp retry mult '$new_cwmp_retry_interval_multiplier'"
  fi
}

make_etc_hosts() {
  atomic /tmp/hosts "$(
    echo "$new_ip_address  $(hostname)"
    echo "127.0.0.1  localhost"
  )"
  log_file_contents /tmp/hosts
}

write_ntp_conf_new()
{
  fname=$1
  atomic "$fname" "$new_ntp_servers"
  log_file_contents "$fname"
}

# Write a JSON encoded blob containing the data needed
# to configure ipv4 on the interface.
make_v4_dynamic_config() {
  atomic "/tmp/ip/dynamic/$interface" "$(
    echo "{ \"$interface\": {"
    echo "  \"ip\": [ {"
    [ -n "${new_ip_address}" ] && \
        echo "    \"new_ip_address\": \"$new_ip_address\","
    [ -n "${new_subnet_mask}" ] && \
        echo "    \"new_subnet_mask\": \"$new_subnet_mask\","
    [ -n "$new_interface_mtu" ] && \
        echo "    \"new_interface_mtu\": \"$new_interface_mtu\","
    [ -n "$new_routers" ] && echo "    \"new_routers\": \"$new_routers\","
    echo "    \"stuffing\": \"filling\" } ],"
    echo "  \"dynamic_pid\": $PPID"
    echo "} }"
  )"
}

ip6_prefix_to_addr() {
  if [ -z "$1" ]; then
    echo ""
    return
  fi

  local prefix=$(echo "$1" | sed -e 's@/..$@@')
  prefix="${prefix}1/64"
  echo "$prefix"
}

ip6_prefix_change() {
  # If neither the old nor the new prefix is set, don't do anything.
  if [ -z "$new_ip6_prefix" ] && [ -z "$old_ip6_prefix" ]; then
    echo 0
    return
  fi

  local new_addr64=$(ip6_prefix_to_addr "$new_ip6_prefix")
  local old_addr64=$(ip6_prefix_to_addr "$old_ip6_prefix")

  # Case 1:  Prefix is being removed.
  if [ -z "$new_addr64" ]; then
    ip -6 addr del "$old_addr64" dev $bridge_ifc
    echo 1
    return
  fi

  # Case 2: Old prefix != newprefix.
  if [ "$old_addr64" != "$new_addr64" ]; then
    if [ -n "$old_addr64" ]; then
      ip -6 addr del "$old_addr64" dev $bridge_ifc
    fi
    ip -6 addr add "$new_addr64" dev $bridge_ifc
    echo 1
    return
  fi

  # Case 3: old prefix = new prefix.  Check if this prefix is already set.
  local addrs
  addrs=$(ip -6 addr show dev $bridge_ifc | grep -i "$new_addr64")
  if [ -n "$addrs" ]; then
    echo 0
    return
  fi

  ip -6 addr add "$new_addr64" dev $bridge_ifc
  echo 1
}

remove_ip6_prefix() {
  # Remove the prefix address that was assigned to the bridge.
  local prefix="$1"
  if [ -n "$prefix" ]; then
    ip -6 addr del $(ip_prefix_to_addr "$prefix") dev $bridge_ifc
    rm -f /tmp/dnsmasq/ipv6.conf
    ip -6 addr flush dev $bridge_ifc scope global
    QUIET=1 restart dnsmasq
  fi
}


# Must be used on exit.   Invokes the local dhcp client exit hooks, if any.
exit_with_hooks() {
  exit_status=$1
  case $reason in
    BOUND|RENEW|REBIND|REBOOT)
      write_ntp_conf_new /tmp/ntpd4.servers
      if [ "$addr_added" = 1 ]; then
        QUIET=1 restart igmpproxy upnpd ssdpd dialserver
        runnable update-acs-iptables && update-acs-iptables
        runnable zebra && QUIET=1 restart quagga
      fi
      ;;

    BOUND6|RENEW6|REBIND6|REBOOT6)
      local restart_dnsmasq
      restart_dnsmasq=$(ip6_prefix_change)
      if [ "$restart_dnsmasq" = 1 ]; then
        local prefix=$(echo "$new_ip6_prefix" | sed -e 's@/..$@@')
        make_dnsmasq_ipv6 "$prefix"
      fi

      if [ "$restart_dnsmasq" != 0 ]; then
        QUIET=1 restart dnsmasq
      fi

      if runnable rdisc6 && \
        [ -n "${new_ip6_address}" ] && [ -n "${interface}" ] && \
        [ "${new_ip6_address}" != "${old_ip6_address}" ]; then
        # If we received a new address, force a router solicitation to
        # be sent, which will force a router advertisement.  We need the
        # RA for setting our default route.
        rdisc6 -1 "${interface}" &
      fi
      write_ntp_conf_new /tmp/ntpd6.servers
      ;;

    EXPIRE|FAIL|RELEASE|STOP)
      echo "Removing DHCP4 ntp servers on $reason"
      rm -f /tmp/ntpd4.servers
      ;;

    EXPIRE6|FAIL6|RELEASE6|STOP6)
      echo "Removing DHCP6 ntp servers on $reason"
      rm -f /tmp/ntpd6.servers
      ;;
  esac
  exit $exit_status
}

###
### DHCPv4 Handlers
###

if [ x$new_broadcast_address != x ]; then
  new_broadcast_arg="broadcast $new_broadcast_address"
fi
if [ x$old_broadcast_address != x ]; then
  old_broadcast_arg="broadcast $old_broadcast_address"
fi
if [ x$IF_METRIC != x ]; then
  metric_arg="metric $IF_METRIC"
fi

if [ x$reason = xMEDIUM ]; then
  # Linux doesn't do mediums (ok, ok, media).
  exit_with_hooks 0
fi

if [ x$reason = xPREINIT ]; then
  $ip link set dev ${interface} up

  # We need to give the kernel some time to get the interface up.
  sleep 1

  exit_with_hooks 0
fi

if [ x$reason = xARPCHECK ] || [ x$reason = xARPSEND ]; then
  exit_with_hooks 0
fi

if [ x$reason = xBOUND ] || [ x$reason = xRENEW ] || \
   [ x$reason = xREBIND ] || [ x$reason = xREBOOT ]; then

  if [ x$old_ip_address = x ] || [ x$old_ip_address != x$new_ip_address ] || \
     [ x$reason = xBOUND ] || [ x$reason = xREBOOT ]; then

    make_v4_dynamic_config
    ipapply ${interface}

    addr_added=1
  fi

  if [ "$addr_added" = 1 ]; then
    # Add a network route to the computed network address.
    if routable_ifc; then
      if [ x$new_routers != x ] && [ x$new_routers != x$old_routers ]; then
         # if we've changed routers delete the old and add the new.
        for router in $old_routers; do
          $ip -4 route del via $router
        done
      fi
      for router in $new_routers; do
        if [ "x$new_subnet_mask" = "x255.255.255.255" ]; then
          $ip -4 route add ${router} dev $interface
        fi
        # ipapply will handle the normal router case.
      done
    fi
  fi

  make_resolv_conf
  make_cwmp_files
  make_etc_hosts
  set-acs bounce
  exit_with_hooks 0
fi

if [ x$reason = xFAIL ] || [ x$reason = xRELEASE ] \
   || [ x$reason = xSTOP ] || [ x$reason = xEXPIRE ]; then
  rm -f "/tmp/ip/dynamic/${interface}"
  ipapply "${interface}"
  exit_with_hooks 0
fi

if [ x$reason = xTIMEOUT ]; then
  rm -f "/tmp/ip/dynamic/${interface}"
  ipapply "${interface}"
  exit_with_hooks 1
fi

###
### DHCPv6 Handlers
###

if [ x$reason = xPREINIT6 ]; then
  # Ensure interface is up.
  $ip link set ${interface} up

  # Remove any stale addresses from aborted clients.
  $ip -f inet6 addr flush dev ${interface} scope global permanent

  exit_with_hooks 0
fi

if [ x${old_ip6_prefix} != x ] || [ x${new_ip6_prefix} != x ]; then
    echo Prefix ${reason} old=${old_ip6_prefix} new=${new_ip6_prefix}

    exit_with_hooks 0
fi

if [ x$reason = xBOUND6 ]; then
  if [ x${new_ip6_address} = x ] || [ x${new_ip6_prefixlen} = x ]; then
    exit_with_hooks 2;
  fi

  $ip -f inet6 addr add ${new_ip6_address}/${new_ip6_prefixlen} \
        dev ${interface} scope global

  # Check for nameserver options.
  make_resolv_conf
  make_cwmp_files
  exit_with_hooks 0
fi

has_new_ip6_address() {
  local output
  output=$(ip -f inet6 addr show dev "${interface}" | grep "${new_ip6_address}")
  [ -n "$output" ]
}

if [ x$reason = xRENEW6 ] || [ x$reason = xREBIND6 ]; then
  # Part of the DHCPv6 spec says that a RENEW6 can send a new and
  # different address.
  if [ -n "${new_ip6_address}" ] && [ "${new_max_life}" != 0 ] && \
    ! has_new_ip6_address; then
    if [ -z "${new_ip6_prefixlen}" ]; then
      # Should never happen, we got a valid address, but no prefixlen.
      exit_with_hooks 2;
    fi
    $ip -f inet6 addr add ${new_ip6_address}/${new_ip6_prefixlen} \
      dev ${interface} scope global
  fi

  # Make sure nothing has moved around on us.

  # Nameservers/domains/etc.
  if [ "x${new_dhcp6_name_servers}" != "x${old_dhcp6_name_servers}" ] ||
     [ "x${new_dhcp6_domain_search}" != "x${old_dhcp6_domain_search}" ]; then
    make_resolv_conf
  fi

  if [ "x${new_cwmp_acs_url}" != "x${old_cwmp_acs_url}" ] ||
     [ "x${new_cwmp_provisioning_code}" != "x${old_cwmp_provisioning_code}" ] ||
     [ "x${new_cwmp_retry_minimum_wait_interval}" != "x${old_cwmp_retry_minimum_wait_interval}" ] ||
     [ "x${new_cwmp_retry_interval_multiplier}" != "x${old_cwmp_retry_interval_multiplier}" ]; then
    make_cwmp_files
  fi

  exit_with_hooks 0
fi

if [ x$reason = xDEPREF6 ]; then
  # If cur_ip_prefixlen is not set then call exit_with_hooks with 2
  # to indicate an error.
  if [ x${cur_ip6_prefixlen} = x ]; then
    exit_with_hooks 2;
  fi

  # This section handles removing the delegated prefix.
  if [ -n "$cur_ip6_prefix" ]; then
    remove_ip6_prefix $cur_ip6_prefix
  fi

  # This section is for the DPREF'd ip6 address.
  # Just remove the address on depref, setting the preferred_lft to
  # 0 still leaves the address active.
  if [ -n "$cur_ip6_address" ]; then
    $ip -f inet6 addr del ${cur_ip6_address}/${cur_ip6_prefixlen} \
      dev ${interface}
  fi

  exit_with_hooks 0
fi

if [ x$reason = xRELEASE6 -o x$reason = xSTOP6 -o x$reason = xEXPIRE6 ]; then
  if [ x${old_ip6_address} = x ] || [ x${old_ip6_prefixlen} = x ]; then
    exit_with_hooks 2;
  fi

  if [ -n "$old_ip6_prefix" ]; then
    remove_ip6_prefix $old_ip6_prefix
  fi

  if [ -n "$old_ip6_address" ]; then
    $ip -f inet6 addr del ${old_ip6_address}/${old_ip6_prefixlen} \
      dev ${interface}
  fi

  exit_with_hooks 0
fi

exit_with_hooks 0