axfr-get.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 #include "uint32.h"
   4 #include "uint16.h"
   5 #include "stralloc.h"
   6 #include "error.h"
   7 #include "strerr.h"
   8 #include "getln.h"
   9 #include "buffer.h"
  10 #include "exit.h"
  11 #include "open.h"
  12 #include "scan.h"
  13 #include "byte.h"
  14 #include "str.h"
  15 #include "ip4.h"
  16 #include "timeoutread.h"
  17 #include "timeoutwrite.h"
  18 #include "dns.h"
  19
  20 #define FATAL "axfr-get: fatal: "
  21
  22 void die_usage(void)
  23 {
  24   strerr_die1x(100,"axfr-get: usage: axfr-get zone fn fn.tmp");
  25 }
  26 void die_generate(void)
  27 {
  28   strerr_die2sys(111,FATAL,"unable to generate AXFR query: ");
  29 }
  30 void die_parse(void)
  31 {
  32   strerr_die2sys(111,FATAL,"unable to parse AXFR results: ");
  33 }
  34 unsigned int x_copy(char *buf,unsigned int len,unsigned int pos,char *out,unsigned int outlen)
  35 {
  36   pos = dns_packet_copy(buf,len,pos,out,outlen);
  37   if (!pos) die_parse();
  38   return pos;
  39 }
  40 unsigned int x_getname(char *buf,unsigned int len,unsigned int pos,char **out)
  41 {
  42   pos = dns_packet_getname(buf,len,pos,out);
  43   if (!pos) die_parse();
  44   return pos;
  45 }
  46 unsigned int x_skipname(char *buf,unsigned int len,unsigned int pos)
  47 {
  48   pos = dns_packet_skipname(buf,len,pos);
  49   if (!pos) die_parse();
  50   return pos;
  51 }
  52
  53 static char *zone;
  54 unsigned int zonelen;
  55 char *fn;
  56 char *fntmp;
  57
  58 void die_netread(void)
  59 {
  60   strerr_die2sys(111,FATAL,"unable to read from network: ");
  61 }
  62 void die_netwrite(void)
  63 {
  64   strerr_die2sys(111,FATAL,"unable to write to network: ");
  65 }
  66 void die_read(void)
  67 {
  68   strerr_die4sys(111,FATAL,"unable to read ",fn,": ");
  69 }
  70 void die_write(void)
  71 {
  72   strerr_die4sys(111,FATAL,"unable to write ",fntmp,": ");
  73 }
  74
  75 int saferead(int fd,char *buf,unsigned int len)
  76 {
  77   int r;
  78   r = timeoutread(60,fd,buf,len);
  79   if (r == 0) { errno = error_proto; die_parse(); }
  80   if (r <= 0) die_netread();
  81   return r;
  82 }
  83 int safewrite(int fd,char *buf,unsigned int len)
  84 {
  85   int r;
  86   r = timeoutwrite(60,fd,buf,len);
  87   if (r <= 0) die_netwrite();
  88   return r;
  89 }
  90 char netreadspace[1024];
  91 buffer netread = BUFFER_INIT(saferead,6,netreadspace,sizeof netreadspace);
  92 char netwritespace[1024];
  93 buffer netwrite = BUFFER_INIT(safewrite,7,netwritespace,sizeof netwritespace);
  94
  95 void netget(char *buf,unsigned int len)
  96 {
  97   int r;
  98
  99   while (len > 0) {
 100     r = buffer_get(&netread,buf,len);
 101     buf += r; len -= r;
 102   }
 103 }
 104
 105 int fd;
 106 buffer b;
 107 char bspace[1024];
 108
 109 void put(char *buf,unsigned int len)
 110 {
 111   if (buffer_put(&b,buf,len) == -1) die_write();
 112 }
 113
 114 int printable(char ch)
 115 {
 116   if (ch == '.') return 1;
 117   if ((ch >= 'a') && (ch <= 'z')) return 1;
 118   if ((ch >= '0') && (ch <= '9')) return 1;
 119   if ((ch >= 'A') && (ch <= 'Z')) return 1;
 120   if (ch == '-') return 1;
 121   return 0;
 122 }
 123
 124 static char *d1;
 125 static char *d2;
 126 static char *d3;
 127
 128 stralloc line;
 129 int match;
 130
 131 int numsoa;
 132
 133 unsigned int doit(char *buf,unsigned int len,unsigned int pos)
 134 {
 135   char data[20];
 136   uint32 ttl;
 137   uint16 dlen;
 138   uint16 typenum;
 139   uint32 u32;
 140   int i;
 141
 142   pos = x_getname(buf,len,pos,&d1);
 143   pos = x_copy(buf,len,pos,data,10);
 144   uint16_unpack_big(data,&typenum);
 145   uint32_unpack_big(data + 4,&ttl);
 146   uint16_unpack_big(data + 8,&dlen);
 147   if (len - pos < dlen) { errno = error_proto; return 0; }
 148   len = pos + dlen;
 149
 150   if (!dns_domain_suffix(d1,zone)) return len;
 151   if (byte_diff(data + 2,2,DNS_C_IN)) return len;
 152
 153   if (byte_equal(data,2,DNS_T_SOA)) {
 154     if (++numsoa >= 2) return len;
 155     pos = x_getname(buf,len,pos,&d2);
 156     pos = x_getname(buf,len,pos,&d3);
 157     x_copy(buf,len,pos,data,20);
 158     uint32_unpack_big(data,&u32);
 159     if (!stralloc_copys(&line,"#")) return 0;
 160     if (!stralloc_catulong0(&line,u32,0)) return 0;
 161     if (!stralloc_cats(&line," auto axfr-get\n")) return 0;
 162     if (!stralloc_cats(&line,"Z")) return 0;
 163     if (!dns_domain_todot_cat(&line,d1)) return 0;
 164     if (!stralloc_cats(&line,":")) return 0;
 165     if (!dns_domain_todot_cat(&line,d2)) return 0;
 166     if (!stralloc_cats(&line,".:")) return 0;
 167     if (!dns_domain_todot_cat(&line,d3)) return 0;
 168     if (!stralloc_cats(&line,".")) return 0;
 169     for (i = 0;i < 5;++i) {
 170       uint32_unpack_big(data + 4 * i,&u32);
 171       if (!stralloc_cats(&line,":")) return 0;
 172       if (!stralloc_catulong0(&line,u32,0)) return 0;
 173     }
 174   }
 175   else if (byte_equal(data,2,DNS_T_NS)) {
 176     if (!stralloc_copys(&line,"&")) return 0;
 177     if (byte_equal(d1,2,"\1*")) { errno = error_proto; return 0; }
 178     if (!dns_domain_todot_cat(&line,d1)) return 0;
 179     if (!stralloc_cats(&line,"::")) return 0;
 180     x_getname(buf,len,pos,&d1);
 181     if (!dns_domain_todot_cat(&line,d1)) return 0;
 182     if (!stralloc_cats(&line,".")) return 0;
 183   }
 184   else if (byte_equal(data,2,DNS_T_CNAME)) {
 185     if (!stralloc_copys(&line,"C")) return 0;
 186     if (!dns_domain_todot_cat(&line,d1)) return 0;
 187     if (!stralloc_cats(&line,":")) return 0;
 188     x_getname(buf,len,pos,&d1);
 189     if (!dns_domain_todot_cat(&line,d1)) return 0;
 190     if (!stralloc_cats(&line,".")) return 0;
 191   }
 192   else if (byte_equal(data,2,DNS_T_PTR)) {
 193     if (!stralloc_copys(&line,"^")) return 0;
 194     if (!dns_domain_todot_cat(&line,d1)) return 0;
 195     if (!stralloc_cats(&line,":")) return 0;
 196     x_getname(buf,len,pos,&d1);
 197     if (!dns_domain_todot_cat(&line,d1)) return 0;
 198     if (!stralloc_cats(&line,".")) return 0;
 199   }
 200   else if (byte_equal(data,2,DNS_T_MX)) {
 201     uint16 dist;
 202     if (!stralloc_copys(&line,"@")) return 0;
 203     if (!dns_domain_todot_cat(&line,d1)) return 0;
 204     if (!stralloc_cats(&line,"::")) return 0;
 205     pos = x_copy(buf,len,pos,data,2);
 206     uint16_unpack_big(data,&dist);
 207     x_getname(buf,len,pos,&d1);
 208     if (!dns_domain_todot_cat(&line,d1)) return 0;
 209     if (!stralloc_cats(&line,".:")) return 0;
 210     if (!stralloc_catulong0(&line,dist,0)) return 0;
 211   }
 212   else if (byte_equal(data,2,DNS_T_A) && (dlen == 4)) {
 213     char ipstr[IP4_FMT];
 214     if (!stralloc_copys(&line,"+")) return 0;
 215     if (!dns_domain_todot_cat(&line,d1)) return 0;
 216     if (!stralloc_cats(&line,":")) return 0;
 217     x_copy(buf,len,pos,data,4);
 218     if (!stralloc_catb(&line,ipstr,ip4_fmt(ipstr,data))) return 0;
 219   }
 220   else {
 221     unsigned char ch;
 222     unsigned char ch2;
 223     if (!stralloc_copys(&line,":")) return 0;
 224     if (!dns_domain_todot_cat(&line,d1)) return 0;
 225     if (!stralloc_cats(&line,":")) return 0;
 226     if (!stralloc_catulong0(&line,typenum,0)) return 0;
 227     if (!stralloc_cats(&line,":")) return 0;
 228     for (i = 0;i < dlen;++i) {
 229       pos = x_copy(buf,len,pos,data,1);
 230       ch = data[0];
 231       if (printable(ch)) {
 232         if (!stralloc_catb(&line,&ch,1)) return 0;
 233       }
 234       else {
 235         if (!stralloc_cats(&line,"\\")) return 0;
 236         ch2 = '0' + ((ch >> 6) & 7);
 237         if (!stralloc_catb(&line,&ch2,1)) return 0;
 238         ch2 = '0' + ((ch >> 3) & 7);
 239         if (!stralloc_catb(&line,&ch2,1)) return 0;
 240         ch2 = '0' + (ch & 7);
 241         if (!stralloc_catb(&line,&ch2,1)) return 0;
 242       }
 243     }
 244   }
 245   if (!stralloc_cats(&line,":")) return 0;
 246   if (!stralloc_catulong0(&line,ttl,0)) return 0;
 247   if (!stralloc_cats(&line,"\n")) return 0;
 248   put(line.s,line.len);
 249
 250   return len;
 251 }
 252
 253 stralloc packet;
 254
 255 int main(int argc,char **argv)
 256 {
 257   char out[20];
 258   unsigned long u;
 259   uint16 dlen;
 260   unsigned int pos;
 261   uint32 oldserial = 0;
 262   uint32 newserial = 0;
 263   uint16 numqueries;
 264   uint16 numanswers;
 265
 266   if (!*argv) die_usage();
 267
 268   if (!*++argv) die_usage();
 269   if (!dns_domain_fromdot(&zone,*argv,str_len(*argv))) die_generate();
 270   zonelen = dns_domain_length(zone);
 271
 272   if (!*++argv) die_usage();
 273   fn = *argv;
 274   if (!*++argv) die_usage();
 275   fntmp = *argv;
 276
 277   fd = open_read(fn);
 278   if (fd == -1) {
 279     if (errno != error_noent) die_read();
 280   }
 281   else {
 282     buffer_init(&b,buffer_unixread,fd,bspace,sizeof bspace);
 283     if (getln(&b,&line,&match,'\n') == -1) die_read();
 284     if (!stralloc_0(&line)) die_read();
 285     if (line.s[0] == '#') {
 286       scan_ulong(line.s + 1,&u);
 287       oldserial = u;
 288     }
 289     close(fd);
 290   }
 291
 292   if (!stralloc_copyb(&packet,"\0\0\0\0\0\1\0\0\0\0\0\0",12)) die_generate();
 293   if (!stralloc_catb(&packet,zone,zonelen)) die_generate();
 294   if (!stralloc_catb(&packet,DNS_T_SOA DNS_C_IN,4)) die_generate();
 295   uint16_pack_big(out,packet.len);
 296   buffer_put(&netwrite,out,2);
 297   buffer_put(&netwrite,packet.s,packet.len);
 298   buffer_flush(&netwrite);
 299
 300   netget(out,2);
 301   uint16_unpack_big(out,&dlen);
 302   if (!stralloc_ready(&packet,dlen)) die_parse();
 303   netget(packet.s,dlen);
 304   packet.len = dlen;
 305
 306   pos = x_copy(packet.s,packet.len,0,out,12);
 307   uint16_unpack_big(out + 4,&numqueries);
 308   uint16_unpack_big(out + 6,&numanswers);
 309
 310   while (numqueries) {
 311     --numqueries;
 312     pos = x_skipname(packet.s,packet.len,pos);
 313     pos += 4;
 314   }
 315
 316   if (!numanswers) { errno = error_proto; die_parse(); }
 317   pos = x_getname(packet.s,packet.len,pos,&d1);
 318   if (!dns_domain_equal(zone,d1)) { errno = error_proto; die_parse(); }
 319   pos = x_copy(packet.s,packet.len,pos,out,10);
 320   if (byte_diff(out,4,DNS_T_SOA DNS_C_IN)) { errno = error_proto; die_parse(); }
 321   pos = x_skipname(packet.s,packet.len,pos);
 322   pos = x_skipname(packet.s,packet.len,pos);
 323   pos = x_copy(packet.s,packet.len,pos,out,4);
 324
 325   uint32_unpack_big(out,&newserial);
 326
 327
 328   if (oldserial && newserial) /* allow 0 for very recently modified zones */
 329     if (oldserial == newserial) /* allow serial numbers to move backwards */
 330       _exit(0);
 331
 332
 333   fd = open_trunc(fntmp);
 334   if (fd == -1) die_write();
 335   buffer_init(&b,buffer_unixwrite,fd,bspace,sizeof bspace);
 336
 337   if (!stralloc_copyb(&packet,"\0\0\0\0\0\1\0\0\0\0\0\0",12)) die_generate();
 338   if (!stralloc_catb(&packet,zone,zonelen)) die_generate();
 339   if (!stralloc_catb(&packet,DNS_T_AXFR DNS_C_IN,4)) die_generate();
 340   uint16_pack_big(out,packet.len);
 341   buffer_put(&netwrite,out,2);
 342   buffer_put(&netwrite,packet.s,packet.len);
 343   buffer_flush(&netwrite);
 344
 345   numsoa = 0;
 346   while (numsoa < 2) {
 347     netget(out,2);
 348     uint16_unpack_big(out,&dlen);
 349     if (!stralloc_ready(&packet,dlen)) die_parse();
 350     netget(packet.s,dlen);
 351     packet.len = dlen;
 352
 353     pos = x_copy(packet.s,packet.len,0,out,12);
 354     uint16_unpack_big(out + 4,&numqueries);
 355
 356     while (numqueries) {
 357       --numqueries;
 358       pos = x_skipname(packet.s,packet.len,pos);
 359       pos += 4;
 360     }
 361     while (pos < packet.len) {
 362       pos = doit(packet.s,packet.len,pos);
 363       if (!pos) die_parse();
 364     }
 365   }
 366
 367   if (buffer_flush(&b) == -1) die_write();
 368   if (fsync(fd) == -1) die_write();
 369   if (close(fd) == -1) die_write(); /* NFS dorks */
 370   if (rename(fntmp,fn) == -1)
 371     strerr_die6sys(111,FATAL,"unable to move ",fntmp," to ",fn,": ");
 372   _exit(0);
 373 }