external/bsd/dhcpcd/dist/dhcpcd-hooks/20-resolv.conf

   1 # $NetBSD: 20-resolv.conf,v 1.8 2015/08/21 10:39:00 roy Exp $
   2
   3 # Generate /etc/resolv.conf
   4 # Support resolvconf(8) if available
   5 # We can merge other dhcpcd resolv.conf files into one like resolvconf,
   6 # but resolvconf is preferred as other applications like VPN clients
   7 # can readily hook into it.
   8 # Also, resolvconf can configure local nameservers such as bind
   9 # or dnsmasq. This is important as the libc resolver isn't that powerful.
  10
  11 resolv_conf_dir="$state_dir/resolv.conf"
  12 NL="
  13 "
  14
  15 build_resolv_conf()
  16 {
  17         local cf="$state_dir/resolv.conf.$ifname"
  18         local interfaces= header= search= srvs= servers= x=
  19
  20         # Build a list of interfaces
  21         interfaces=$(list_interfaces "$resolv_conf_dir")
  22
  23         # Build the resolv.conf
  24         if [ -n "$interfaces" ]; then
  25                 # Build the header
  26                 for x in ${interfaces}; do
  27                         header="$header${header:+, }$x"
  28                 done
  29
  30                 # Build the search list
  31                 domain=$(cd "$resolv_conf_dir"; \
  32                         key_get_value "domain " ${interfaces})
  33                 search=$(cd "$resolv_conf_dir"; \
  34                         key_get_value "search " ${interfaces})
  35                 set -- ${domain}
  36                 domain="$1"
  37                 [ -n "$2" ] && search="$search $*"
  38                 [ -n "$search" ] && search="$(uniqify $search)"
  39                 [ "$domain" = "$search" ] && search=
  40                 [ -n "$domain" ] && domain="domain $domain$NL"
  41                 [ -n "$search" ] && search="search $search$NL"
  42
  43                 # Build the nameserver list
  44                 srvs=$(cd "$resolv_conf_dir"; \
  45                         key_get_value "nameserver " ${interfaces})
  46                 for x in $(uniqify ${srvs}); do
  47                         servers="${servers}nameserver $x$NL"
  48                 done
  49         fi
  50         header="$signature_base${header:+ $from }$header"
  51
  52         # Assemble resolv.conf using our head and tail files
  53         [ -f "$cf" ] && rm -f "$cf"
  54         [ -d "$resolv_conf_dir" ] || mkdir -p "$resolv_conf_dir"
  55         echo "$header" > "$cf"
  56         if [ -f /etc/resolv.conf.head ]; then
  57                 cat /etc/resolv.conf.head >> "$cf"
  58         else
  59                 echo "# /etc/resolv.conf.head can replace this line" >> "$cf"
  60         fi
  61         printf %s "$domain$search$servers" >> "$cf"
  62         if [ -f /etc/resolv.conf.tail ]; then
  63                 cat /etc/resolv.conf.tail >> "$cf"
  64         else
  65                 echo "# /etc/resolv.conf.tail can replace this line" >> "$cf"
  66         fi
  67         if change_file /etc/resolv.conf "$cf"; then
  68                 chmod 644 /etc/resolv.conf
  69         fi
  70         rm -f "$cf"
  71 }
  72
  73 # Extract any ND DNS options from the RA
  74 # For now, we ignore the lifetime of the DNS options unless they
  75 # are absent or zero.
  76 # In this case they are removed from consideration.
  77 # See draft-gont-6man-slaac-dns-config-issues-01 for issues
  78 # regarding DNS option lifetime in ND messages.
  79 eval_nd_dns()
  80 {
  81
  82         eval ltime=\$nd${i}_rdnss${j}_lifetime
  83         if [ -z "$ltime" -o "$ltime" = 0 ]; then
  84                 rdnss=
  85         else
  86                 eval rdnss=\$nd${i}_rdnss${j}_servers
  87         fi
  88         eval ltime=\$nd${i}_dnssl${j}_lifetime
  89         if [ -z "$ltime" -o "$ltime" = 0 ]; then
  90                 dnssl=
  91         else
  92                 eval dnssl=\$nd${i}_dnssl${j}_search
  93         fi
  94
  95         [ -z "$rdnss" -a -z "$dnssl" ] && return 1
  96
  97         new_rdnss="$new_rdnss${new_rdnss:+ }$rdnss"
  98         new_dnssl="$new_dnssl${new_dnssl:+ }$dnssl"
  99         j=$(($j + 1))
 100         return 0
 101 }
 102
 103 add_resolv_conf()
 104 {
 105         local x= conf="$signature$NL" warn=true
 106         local i j ltime rdnss dnssl new_rdnss new_dnssl
 107
 108         # Loop to extract the ND DNS options using our indexed shell values
 109         i=1
 110         j=1
 111         while true; do
 112                 while true; do
 113                         eval_nd_dns || break
 114                 done
 115                 i=$(($i + 1))
 116                 j=1
 117                 eval_nd_dns || break
 118         done
 119         new_domain_name_servers="$new_domain_name_servers${new_domain_name_servers:+ }$new_rdnss"
 120         new_domain_search="$new_domain_search${new_domain_search:+ }$new_dnssl"
 121
 122         # Derive a new domain from our various hostname options
 123         if [ -z "$new_domain_name" ]; then
 124                 if [ "$new_dhcp6_fqdn" != "${new_dhcp6_fqdn#*.}" ]; then
 125                         new_domain_name="${new_dhcp6_fqdn#*.}"
 126                 elif [ "$new_fqdn" != "${new_fqdn#*.}" ]; then
 127                         new_domain_name="${new_fqdn#*.}"
 128                 elif [ "$new_host_name" != "${new_host_name#*.}" ]; then
 129                         new_domain_name="${new_host_name#*.}"
 130                 fi
 131         fi
 132
 133         # If we don't have any configuration, remove it
 134         if [ -z "$new_domain_name_servers" -a \
 135                 -z "$new_domain_name" -a \
 136                 -z "$new_domain_search" ]; then
 137                 remove_resolv_conf
 138                 return $?
 139         fi
 140
 141         if [ -n "$new_domain_name" ]; then
 142                 set -- $new_domain_name
 143                 if valid_domainname "$1"; then
 144                         conf="${conf}domain $1$NL"
 145                 else
 146                         syslog err "Invalid domain name: $1"
 147                 fi
 148                 # If there is no search this, make this one
 149                 if [ -z "$new_domain_search" ]; then
 150                         new_domain_search="$new_domain_name"
 151                         [ "$new_domain_name" = "$1" ] && warn=true
 152                 fi
 153         fi
 154         if [ -n "$new_domain_search" ]; then
 155                 if valid_domainname_list $new_domain_search; then
 156                         conf="${conf}search $new_domain_search$NL"
 157                 elif ! $warn; then
 158                         syslog err "Invalid domain name in list:" \
 159                             "$new_domain_search"
 160                 fi
 161         fi
 162         for x in ${new_domain_name_servers}; do
 163                 conf="${conf}nameserver $x$NL"
 164         done
 165         if type resolvconf >/dev/null 2>&1; then
 166                 [ -n "$ifmetric" ] && export IF_METRIC="$ifmetric"
 167                 printf %s "$conf" | resolvconf -a "$ifname"
 168                 return $?
 169         fi
 170
 171         if [ -e "$resolv_conf_dir/$ifname" ]; then
 172                 rm -f "$resolv_conf_dir/$ifname"
 173         fi
 174         [ -d "$resolv_conf_dir" ] || mkdir -p "$resolv_conf_dir"
 175         printf %s "$conf" > "$resolv_conf_dir/$ifname"
 176         build_resolv_conf
 177 }
 178
 179 remove_resolv_conf()
 180 {
 181         if type resolvconf >/dev/null 2>&1; then
 182                 resolvconf -d "$ifname" -f
 183         else
 184                 if [ -e "$resolv_conf_dir/$ifname" ]; then
 185                         rm -f "$resolv_conf_dir/$ifname"
 186                 fi
 187                 build_resolv_conf
 188         fi
 189 }
 190
 191 # For ease of use, map DHCP6 names onto our DHCP4 names
 192 case "$reason" in
 193 BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6)
 194         new_domain_name_servers="$new_dhcp6_name_servers"
 195         new_domain_search="$new_dhcp6_domain_search"
 196         ;;
 197 esac
 198
 199 if $if_up || [ "$reason" = ROUTERADVERT ]; then
 200         add_resolv_conf
 201 elif $if_down; then
 202         remove_resolv_conf
 203 fi