# Generate /etc/resolv.conf # Support resolvconf(8) if available # We can merge other dhcpcd resolv.conf files into one like resolvconf, # but resolvconf is preferred as other applications like VPN clients # can readily hook into it. # Also, resolvconf can configure local nameservers such as bind # or dnsmasq. This is important as the libc resolver isn't that powerful. resolv_conf_dir="$state_dir/resolv.conf" nocarrier_roaming_dir="$state_dir/roaming" NL=" " : ${resolvconf:=resolvconf} if command -v "$resolvconf" >/dev/null 2>&1; then have_resolvconf=true else have_resolvconf=false fi build_resolv_conf() { cf="$state_dir/resolv.conf.$ifname" # Build a list of interfaces interfaces=$(list_interfaces "$resolv_conf_dir") # Build the resolv.conf header= if [ -n "$interfaces" ]; then # Build the header for x in ${interfaces}; do header="$header${header:+, }$x" done # Build the search list domain=$(cd "$resolv_conf_dir"; \ key_get_value "domain " ${interfaces}) search=$(cd "$resolv_conf_dir"; \ key_get_value "search " ${interfaces}) set -- ${domain} domain="$1" [ -n "$2" ] && search="$search $*" [ -n "$search" ] && search="$(uniqify $search)" [ "$domain" = "$search" ] && search= [ -n "$domain" ] && domain="domain $domain$NL" [ -n "$search" ] && search="search $search$NL" # Build the nameserver list srvs=$(cd "$resolv_conf_dir"; \ key_get_value "nameserver " ${interfaces}) for x in $(uniqify $srvs); do servers="${servers}nameserver $x$NL" done fi header="$signature_base${header:+ $from }$header" # Assemble resolv.conf using our head and tail files [ -f "$cf" ] && rm -f "$cf" [ -d "$resolv_conf_dir" ] || mkdir -p "$resolv_conf_dir" echo "$header" > "$cf" if [ -f /etc/resolv.conf.head ]; then cat /etc/resolv.conf.head >> "$cf" else echo "# /etc/resolv.conf.head can replace this line" >> "$cf" fi printf %s "$domain$search$servers" >> "$cf" if [ -f /etc/resolv.conf.tail ]; then cat /etc/resolv.conf.tail >> "$cf" else echo "# /etc/resolv.conf.tail can replace this line" >> "$cf" fi if change_file /etc/resolv.conf "$cf"; then chmod 644 /etc/resolv.conf fi rm -f "$cf" } # Extract any ND DNS options from the RA # Obey the lifetimes eval_nd_dns() { eval rdnsstime=\$nd${i}_rdnss${j}_lifetime [ -z "$rdnsstime" ] && return 1 ltime=$(($rdnsstime - $offset)) if [ "$ltime" -gt 0 ]; then eval rdnss=\$nd${i}_rdnss${j}_servers [ -n "$rdnss" ] && new_rdnss="$new_rdnss${new_rdnss:+ }$rdnss" fi eval dnssltime=\$nd${i}_dnssl${j}_lifetime [ -z "$dnssltime" ] && return 1 ltime=$(($dnssltime - $offset)) if [ "$ltime" -gt 0 ]; then eval dnssl=\$nd${i}_dnssl${j}_search [ -n "$dnssl" ] && new_dnssl="$new_dnssl${new_dnssl:+ }$dnssl" fi j=$(($j + 1)) return 0 } add_resolv_conf() { conf="$signature$NL" warn=true # Loop to extract the ND DNS options using our indexed shell values i=1 j=1 while true; do eval acquired=\$nd${i}_acquired [ -z "$acquired" ] && break eval now=\$nd${i}_now [ -z "$now" ] && break offset=$(($now - $acquired)) while true; do eval_nd_dns || break done i=$(($i + 1)) j=1 done [ -n "$new_rdnss" ] && \ new_domain_name_servers="$new_domain_name_servers${new_domain_name_servers:+ }$new_rdnss" [ -n "$new_dnssl" ] && \ new_domain_search="$new_domain_search${new_domain_search:+ }$new_dnssl" # Derive a new domain from our various hostname options if [ -z "$new_domain_name" ]; then if [ "$new_dhcp6_fqdn" != "${new_dhcp6_fqdn#*.}" ]; then new_domain_name="${new_dhcp6_fqdn#*.}" elif [ "$new_fqdn" != "${new_fqdn#*.}" ]; then new_domain_name="${new_fqdn#*.}" elif [ "$new_host_name" != "${new_host_name#*.}" ]; then new_domain_name="${new_host_name#*.}" fi fi # If we don't have any configuration, remove it if [ -z "$new_domain_name_servers" ] && [ -z "$new_domain_name" ] && [ -z "$new_domain_search" ]; then remove_resolv_conf return $? fi if [ -n "$new_domain_name" ]; then set -- $new_domain_name if valid_domainname "$1"; then conf="${conf}domain $1$NL" else syslog err "Invalid domain name: $1" fi # If there is no search this, make this one if [ -z "$new_domain_search" ]; then new_domain_search="$new_domain_name" [ "$new_domain_name" = "$1" ] && warn=true fi fi if [ -n "$new_domain_search" ]; then new_domain_search=$(uniqify $new_domain_search) if valid_domainname_list $new_domain_search; then conf="${conf}search $new_domain_search$NL" elif ! $warn; then syslog err "Invalid domain name in list:" \ "$new_domain_search" fi fi new_domain_name_servers=$(uniqify $new_domain_name_servers) for x in ${new_domain_name_servers}; do conf="${conf}nameserver $x$NL" done if $have_resolvconf; then [ -n "$ifmetric" ] && export IF_METRIC="$ifmetric" printf %s "$conf" | "$resolvconf" -a "$ifname" return $? fi if [ -e "$resolv_conf_dir/$ifname" ]; then rm -f "$resolv_conf_dir/$ifname" fi [ -d "$resolv_conf_dir" ] || mkdir -p "$resolv_conf_dir" printf %s "$conf" > "$resolv_conf_dir/$ifname" build_resolv_conf } remove_resolv_conf() { if $have_resolvconf; then "$resolvconf" -d "$ifname" -f else if [ -e "$resolv_conf_dir/$ifname" ]; then rm -f "$resolv_conf_dir/$ifname" fi build_resolv_conf fi } # For ease of use, map DHCP6 names onto our DHCP4 names case "$reason" in BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6) new_domain_name_servers="$new_dhcp6_name_servers" new_domain_search="$new_dhcp6_domain_search" ;; esac if $if_configured; then if $have_resolvconf && [ "$reason" = NOCARRIER_ROAMING ]; then # avoid calling resolvconf -c on CARRIER unless we roam mkdir -p "$nocarrier_roaming_dir" echo " " >"$nocarrier_roaming_dir/$interface" "$resolvconf" -C "$interface.*" elif $have_resolvconf && [ "$reason" = CARRIER ]; then # Not all resolvconf implementations support -c if [ -e "$nocarrier_roaming_dir/$interface" ]; then rm -f "$nocarrier_roaming_dir/$interface" "$resolvconf" -c "$interface.*" fi elif $if_up || [ "$reason" = ROUTERADVERT ]; then add_resolv_conf elif $if_down; then remove_resolv_conf fi fi