20-resolv.conf revision 1.4
1 # Generate /etc/resolv.conf 2 # Support resolvconf(8) if available 3 # We can merge other dhcpcd resolv.conf files into one like resolvconf, 4 # but resolvconf is preferred as other applications like VPN clients 5 # can readily hook into it. 6 # Also, resolvconf can configure local nameservers such as bind 7 # or dnsmasq. This is important as the libc resolver isn't that powerful. 8 9 resolv_conf_dir="$state_dir/resolv.conf" 10 NL=" 11 " 12 : ${resolvconf:=resolvconf} 13 14 build_resolv_conf() 15 { 16 cf="$state_dir/resolv.conf.$ifname" 17 18 # Build a list of interfaces 19 interfaces=$(list_interfaces "$resolv_conf_dir") 20 21 # Build the resolv.conf 22 header= 23 if [ -n "$interfaces" ]; then 24 # Build the header 25 for x in ${interfaces}; do 26 header="$header${header:+, }$x" 27 done 28 29 # Build the search list 30 domain=$(cd "$resolv_conf_dir"; \ 31 key_get_value "domain " ${interfaces}) 32 search=$(cd "$resolv_conf_dir"; \ 33 key_get_value "search " ${interfaces}) 34 set -- ${domain} 35 domain="$1" 36 [ -n "$2" ] && search="$search $*" 37 [ -n "$search" ] && search="$(uniqify $search)" 38 [ "$domain" = "$search" ] && search= 39 [ -n "$domain" ] && domain="domain $domain$NL" 40 [ -n "$search" ] && search="search $search$NL" 41 42 # Build the nameserver list 43 srvs=$(cd "$resolv_conf_dir"; \ 44 key_get_value "nameserver " ${interfaces}) 45 for x in $(uniqify $srvs); do 46 servers="${servers}nameserver $x$NL" 47 done 48 fi 49 header="$signature_base${header:+ $from }$header" 50 51 # Assemble resolv.conf using our head and tail files 52 [ -f "$cf" ] && rm -f "$cf" 53 [ -d "$resolv_conf_dir" ] || mkdir -p "$resolv_conf_dir" 54 echo "$header" > "$cf" 55 if [ -f /etc/resolv.conf.head ]; then 56 cat /etc/resolv.conf.head >> "$cf" 57 else 58 echo "# /etc/resolv.conf.head can replace this line" >> "$cf" 59 fi 60 printf %s "$domain$search$servers" >> "$cf" 61 if [ -f /etc/resolv.conf.tail ]; then 62 cat /etc/resolv.conf.tail >> "$cf" 63 else 64 echo "# /etc/resolv.conf.tail can replace this line" >> "$cf" 65 fi 66 if change_file /etc/resolv.conf "$cf"; then 67 chmod 644 /etc/resolv.conf 68 fi 69 rm -f "$cf" 70 } 71 72 # Extract any ND DNS options from the RA 73 # Obey the lifetimes 74 eval_nd_dns() 75 { 76 77 eval rdnsstime=\$nd${i}_rdnss${j}_lifetime 78 [ -z "$rdnsstime" ] && return 1 79 ltime=$(($rdnsstime - $offset)) 80 if [ "$ltime" -gt 0 ]; then 81 eval rdnss=\$nd${i}_rdnss${j}_servers 82 [ -n "$rdnss" ] && new_rdnss="$new_rdnss${new_rdnss:+ }$rdnss" 83 fi 84 85 eval dnssltime=\$nd${i}_dnssl${j}_lifetime 86 [ -z "$dnssltime" ] && return 1 87 ltime=$(($dnssltime - $offset)) 88 if [ "$ltime" -gt 0 ]; then 89 eval dnssl=\$nd${i}_dnssl${j}_search 90 [ -n "$dnssl" ] && new_dnssl="$new_dnssl${new_dnssl:+ }$dnssl" 91 fi 92 93 j=$(($j + 1)) 94 return 0 95 } 96 97 add_resolv_conf() 98 { 99 conf="$signature$NL" 100 warn=true 101 102 # Loop to extract the ND DNS options using our indexed shell values 103 i=1 104 j=1 105 while true; do 106 eval acquired=\$nd${i}_acquired 107 [ -z "$acquired" ] && break 108 eval now=\$nd${i}_now 109 [ -z "$now" ] && break 110 offset=$(($now - $acquired)) 111 while true; do 112 eval_nd_dns || break 113 done 114 i=$(($i + 1)) 115 j=1 116 done 117 [ -n "$new_rdnss" ] && \ 118 new_domain_name_servers="$new_domain_name_servers${new_domain_name_servers:+ }$new_rdnss" 119 [ -n "$new_dnssl" ] && \ 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" ] && 135 [ -z "$new_domain_name" ] && 136 [ -z "$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 new_domain_search=$(uniqify $new_domain_search) 156 if valid_domainname_list $new_domain_search; then 157 conf="${conf}search $new_domain_search$NL" 158 elif ! $warn; then 159 syslog err "Invalid domain name in list:" \ 160 "$new_domain_search" 161 fi 162 fi 163 new_domain_name_servers=$(uniqify $new_domain_name_servers) 164 for x in ${new_domain_name_servers}; do 165 conf="${conf}nameserver $x$NL" 166 done 167 if type "$resolvconf" >/dev/null 2>&1; then 168 [ -n "$ifmetric" ] && export IF_METRIC="$ifmetric" 169 printf %s "$conf" | "$resolvconf" -a "$ifname" 170 return $? 171 fi 172 173 if [ -e "$resolv_conf_dir/$ifname" ]; then 174 rm -f "$resolv_conf_dir/$ifname" 175 fi 176 [ -d "$resolv_conf_dir" ] || mkdir -p "$resolv_conf_dir" 177 printf %s "$conf" > "$resolv_conf_dir/$ifname" 178 build_resolv_conf 179 } 180 181 remove_resolv_conf() 182 { 183 if type "$resolvconf" >/dev/null 2>&1; then 184 "$resolvconf" -d "$ifname" -f 185 else 186 if [ -e "$resolv_conf_dir/$ifname" ]; then 187 rm -f "$resolv_conf_dir/$ifname" 188 fi 189 build_resolv_conf 190 fi 191 } 192 193 # For ease of use, map DHCP6 names onto our DHCP4 names 194 case "$reason" in 195 BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6) 196 new_domain_name_servers="$new_dhcp6_name_servers" 197 new_domain_search="$new_dhcp6_domain_search" 198 ;; 199 esac 200 201 if $if_up || [ "$reason" = ROUTERADVERT ]; then 202 add_resolv_conf 203 elif $if_down; then 204 remove_resolv_conf 205 fi 206
Indexes created Mon Apr 06 00:22:49 UTC 2026