odhcpd.awk 6.1 KB

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  1. #!/usr/bin/awk
  2. ##############################################################################
  3. #
  4. # This program is free software; you can redistribute it and/or modify
  5. # it under the terms of the GNU General Public License version 2 as
  6. # published by the Free Software Foundation.
  7. #
  8. # This program is distributed in the hope that it will be useful,
  9. # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11. # GNU General Public License for more details.
  12. #
  13. # Copyright (C) 2016 Eric Luehrsen
  14. #
  15. ##############################################################################
  16. #
  17. # Turn DHCP records into meaningful A, AAAA, and PTR records. Also lift a
  18. # function from dnsmasq and use DHCPv4 MAC to find IPV6 SLAAC hosts.
  19. #
  20. # External Parameters
  21. # "hostfile" = where this script will cache host DNS data
  22. # "domain" = text domain suffix
  23. # "bslaac" = boolean, use DHCPv4 MAC to find GA and ULA IPV6 SLAAC
  24. # "bisolt" = boolean, format <host>.<network>.<domain>. so you can isolate
  25. # "bconf" = boolean, write conf file format rather than pipe records
  26. #
  27. ##############################################################################
  28. /^#/ {
  29. # We need to pick out DHCP v4 or v6 records
  30. net = $2 ; id = $3 ; cls = $4 ; hst = $5 ; adr = $9 ; adr2 = $10
  31. cdr = adr ;
  32. cdr2 = adr2 ;
  33. sub( /\/.*/, "", adr ) ;
  34. sub( /.*\//, "", cdr ) ;
  35. sub( /\/.*/, "", adr2 ) ;
  36. sub( /.*\//, "", cdr2 ) ;
  37. if ( hst !~ /^[[:alnum:]]([-[:alnum:]]*[[:alnum:]])?$/ ) {
  38. # that is not a valid host name (RFC1123)
  39. hst = "-" ;
  40. }
  41. if ( bisolt == 1 ) {
  42. # TODO: this might be better with a substituion option,
  43. # or per DHCP pool do-not-DNS option, but its getting busy here.
  44. fqdn = net
  45. fqdn = sub( /\./, "-", fqdn ) ;
  46. fqdn = tolower( hst "." fqdn "." domain ) ;
  47. }
  48. else {
  49. fqdn = tolower( hst "." domain ) ;
  50. }
  51. if ((cls == "ipv4") && (hst != "-") && (cdr == 32) && (NF == 9)) {
  52. # IPV4 ; only for provided hostnames and full /32 assignments
  53. # NF=9 ; odhcpd errata in field format without host name
  54. ptr = adr ; qpr = "" ; split( ptr, ptr, "." ) ;
  55. slaac = slaac_eui64( id ) ;
  56. if ( bconf == 1 ) {
  57. x = ( "local-data: \"" fqdn ". 120 IN A " adr "\"" ) ;
  58. y = ( "local-data-ptr: \"" adr " 120 " fqdn "\"" ) ;
  59. print ( x "\n" y "\n" ) > hostfile ;
  60. }
  61. else {
  62. for( i=1; i<=4; i++ ) { qpr = ( ptr[i] "." qpr) ; }
  63. x = ( fqdn ". 120 IN A " adr ) ;
  64. y = ( qpr "in-addr.arpa. 120 IN PTR " fqdn ) ;
  65. print ( x "\n" y ) > hostfile ;
  66. }
  67. if (( bslaac == 1 ) && ( slaac != 0 )) {
  68. # UCI option to discover IPV6 routed SLAAC addresses
  69. # NOT TODO - ping probe take too long when added in awk-rule loop
  70. cmd = ( "ip -6 --oneline route show dev " net ) ;
  71. while ( ( cmd | getline adr ) > 0 ) {
  72. if (( substr( adr, 1, 5 ) <= "fdff:" ) \
  73. && ( index( adr, "anycast" ) == 0 ) \
  74. && ( index( adr, "via" ) == 0 )) {
  75. # GA or ULA routed addresses only (not LL or MC)
  76. sub( /\/.*/, "", adr ) ;
  77. adr = ( adr slaac ) ;
  78. if ( split( adr, tmp0, ":" ) > 8 ) {
  79. sub( "::", ":", adr ) ;
  80. }
  81. if ( bconf == 1 ) {
  82. x = ( "local-data: \"" fqdn ". 120 IN AAAA " adr "\"" ) ;
  83. y = ( "local-data-ptr: \"" adr " 120 " fqdn "\"" ) ;
  84. print ( x "\n" y "\n" ) > hostfile ;
  85. }
  86. else {
  87. qpr = ipv6_ptr( adr ) ;
  88. x = ( fqdn ". 120 IN AAAA " adr ) ;
  89. y = ( qpr ". 120 IN PTR " fqdn ) ;
  90. print ( x "\n" y ) > hostfile ;
  91. }
  92. }
  93. }
  94. close( cmd ) ;
  95. }
  96. }
  97. else if ((cls != "ipv4") && (hst != "-") && (9 <= NF) && (NF <= 10)) {
  98. if (cdr == 128) {
  99. if ( bconf == 1 ) {
  100. x = ( "local-data: \"" fqdn ". 120 IN AAAA " adr "\"" ) ;
  101. y = ( "local-data-ptr: \"" adr " 120 " fqdn "\"" ) ;
  102. print ( x "\n" y "\n" ) > hostfile ;
  103. }
  104. else {
  105. # only for provided hostnames and full /128 assignments
  106. qpr = ipv6_ptr( adr ) ;
  107. x = ( fqdn ". 120 IN AAAA " adr ) ;
  108. y = ( qpr ". 120 IN PTR " fqdn ) ;
  109. print ( x "\n" y ) > hostfile ;
  110. }
  111. }
  112. if (cdr2 == 128) {
  113. if ( bconf == 1 ) {
  114. x = ( "local-data: \"" fqdn ". 120 IN AAAA " adr2 "\"" ) ;
  115. y = ( "local-data-ptr: \"" adr2 " 120 " fqdn "\"" ) ;
  116. print ( x "\n" y "\n" ) > hostfile ;
  117. }
  118. else {
  119. # odhcp puts GA and ULA on the same line (position 9 and 10)
  120. qpr2 = ipv6_ptr( adr2 ) ;
  121. x = ( fqdn ". 120 IN AAAA " adr2 ) ;
  122. y = ( qpr2 ". 120 IN PTR " fqdn ) ;
  123. print ( x "\n" y ) > hostfile ;
  124. }
  125. }
  126. }
  127. else {
  128. # dump non-conforming lease records
  129. }
  130. }
  131. ##############################################################################
  132. function ipv6_ptr( ipv6, arpa, ary, end, i, j, new6, sz, start ) {
  133. # IPV6 colon flexibility is a challenge when creating [ptr].ip6.arpa.
  134. sz = split( ipv6, ary, ":" ) ; end = 9 - sz ;
  135. for( i=1; i<=sz; i++ ) {
  136. if( length(ary[i]) == 0 ) {
  137. for( j=1; j<=end; j++ ) { ary[i] = ( ary[i] "0000" ) ; }
  138. }
  139. else {
  140. ary[i] = substr( ( "0000" ary[i] ), length( ary[i] )+5-4 ) ;
  141. }
  142. }
  143. new6 = ary[1] ;
  144. for( i = 2; i <= sz; i++ ) { new6 = ( new6 ary[i] ) ; }
  145. start = length( new6 ) ;
  146. for( i=start; i>0; i-- ) { arpa = ( arpa substr( new6, i, 1 ) ) ; } ;
  147. gsub( /./, "&\.", arpa ) ; arpa = ( arpa "ip6.arpa" ) ;
  148. return arpa ;
  149. }
  150. ##############################################################################
  151. function slaac_eui64( mac, ary, glbit, eui64 ) {
  152. if ( length(mac) >= 12 ) {
  153. # RFC2373 and use DHCPv4 registered MAC to find SLAAC addresses
  154. split( mac , ary , "" ) ;
  155. glbit = ( "0x" ary[2] ) ;
  156. glbit = sprintf( "%d", glbit ) ;
  157. glbit = or( glbit, 2 ) ;
  158. ary[2] = sprintf( "%x", glbit ) ;
  159. eui64 = ( ary[1] ary[2] ary[3] ary[4] ":" ary[5] ary[6] "ff:fe" ) ;
  160. eui64 = ( eui64 ary[7] ary[8] ":" ary[9] ary[10] ary[11] ary[12] ) ;
  161. }
  162. else {
  163. eui64 = 0 ;
  164. }
  165. return eui64 ;
  166. }
  167. ##############################################################################