mdw@git.distorted.org.uk Git - adns/blob - src/adns.c

   1 /**/
   2
   3 #include <stdarg.h>
   4 #include <stdio.h>
   5 #include <errno.h>
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include <assert.h>
   9 #include <unistd.h>
  10
  11 #include <netdb.h>
  12 #include <arpa/nameser.h>
  13 #include <sys/socket.h>
  14 #include <netinet/in.h>
  15 #include <arpa/inet.h>
  16
  17 #include "adns-internal.h"
  18
  19 #define LIST_UNLINK(list,node) \
  20   do { \
  21     if ((node)->back) (node)->back->next= (node)->next; \
  22       else                   (list).head= (node)->next; \
  23     if ((node)->next) (node)->next->back= (node)->back; \
  24       else                   (list).tail= (node)->back; \
  25   } while(0)
  26
  27 #define LIST_LINK_TAIL(list,node) \
  28   do { \
  29     (node)->back= 0; \
  30     (node)->next= (list).tail; \
  31     if ((list).tail) (list).tail->back= (node); else (list).head= (node); \
  32     (list).tail= (node); \
  33   } while(0)
  34
  35 static void vdebug(adns_state ads, const char *fmt, va_list al) {
  36   if (!(ads->iflags & adns_if_debug)) return;
  37   fputs("adns debug: ",stderr);
  38   vfprintf(stderr,fmt,al);
  39   fputc('\n',stderr);
  40 }
  41
  42 static void debug(adns_state ads, const char *fmt, ...) {
  43   va_list al;
  44
  45   va_start(al,fmt);
  46   vdebug(ads,fmt,al);
  47   va_end(al);
  48 }
  49
  50 static void vdiag(adns_state ads, const char *fmt, va_list al) {
  51   if (ads->iflags & adns_if_noerrprint) return;
  52   fputs("adns: ",stderr);
  53   vfprintf(stderr,fmt,al);
  54   fputc('\n',stderr);
  55 }
  56
  57 static void diag(adns_state ads, const char *fmt, ...) {
  58   va_list al;
  59
  60   va_start(al,fmt);
  61   vdiag(ads,fmt,al);
  62   va_end(al);
  63 }
  64
  65 static void addserver(adns_state ads, struct in_addr addr) {
  66   int i;
  67   struct server *ss;
  68
  69   for (i=0; i<ads->nservers; i++) {
  70     if (ads->servers[i].addr.s_addr == addr.s_addr) {
  71       debug(ads,"duplicate nameserver %s ignored",inet_ntoa(addr));
  72       return;
  73     }
  74   }
  75
  76   if (ads->nservers>=MAXSERVERS) {
  77     diag(ads,"too many nameservers, ignoring %s",inet_ntoa(addr));
  78     return;
  79   }
  80
  81   ss= ads->servers+ads->nservers;
  82   ss->addr= addr;
  83   ss->state= server_disc;
  84   ss->connw.head= ss->connw.tail= 0;
  85   ads->nservers++;
  86 }
  87
  88 static void configparseerr(adns_state ads, const char *fn, int lno,
  89                            const char *fmt, ...) {
  90   va_list al;
  91
  92   if (ads->iflags & adns_if_noerrprint) return;
  93   if (lno==-1) fprintf(stderr,"adns: %s: ",fn);
  94   else fprintf(stderr,"adns: %s:%d: ",fn,lno);
  95   va_start(al,fmt);
  96   vfprintf(stderr,fmt,al);
  97   va_end(al);
  98   fputc('\n',stderr);
  99 }
 100
 101 static void ccf_nameserver(adns_state ads, const char *fn, int lno, const char *buf) {
 102   struct in_addr ia;
 103
 104   if (!inet_aton(buf,&ia)) {
 105     configparseerr(ads,fn,lno,"invalid nameserver address `%s'",buf);
 106     return;
 107   }
 108   debug(ads,"using nameserver %s",inet_ntoa(ia));
 109   addserver(ads,ia);
 110 }
 111
 112 static void ccf_search(adns_state ads, const char *fn, int lno, const char *buf) {
 113   if (!buf) return;
 114   diag(ads,"warning - `search' ignored FIXME");
 115 }
 116
 117 static void ccf_sortlist(adns_state ads, const char *fn, int lno, const char *buf) {
 118   diag(ads,"warning - `sortlist' ignored FIXME");
 119 }
 120
 121 static void ccf_options(adns_state ads, const char *fn, int lno, const char *buf) {
 122   if (!buf) return;
 123   diag(ads,"warning - `options' ignored FIXME");
 124 }
 125
 126 static void ccf_clearnss(adns_state ads, const char *fn, int lno, const char *buf) {
 127   ads->nservers= 0;
 128 }
 129
 130 static const struct configcommandinfo {
 131   const char *name;
 132   void (*fn)(adns_state ads, const char *fn, int lno, const char *buf);
 133 } configcommandinfos[]= {
 134   { "nameserver",        ccf_nameserver  },
 135   { "domain",            ccf_search      },
 136   { "search",            ccf_search      },
 137   { "sortlist",          ccf_sortlist    },
 138   { "options",           ccf_options     },
 139   { "clearnameservers",  ccf_clearnss    },
 140   {  0                                   }
 141 };
 142
 143 static int whitespace(int c) {
 144   return c==' ' || c=='\n' || c=='\t';
 145 }
 146
 147 static void readconfig(adns_state ads, const char *filename) {
 148   char linebuf[2000], *p, *q;
 149   FILE *file;
 150   int lno, l, c;
 151   const struct configcommandinfo *ccip;
 152
 153   file= fopen(filename,"r");
 154   if (!file) {
 155     if (errno == ENOENT) {
 156       debug(ads,"configuration file `%s' does not exist",filename);
 157       return;
 158     }
 159     diag(ads,"cannot open configuration file `%s': %s",filename,strerror(errno));
 160     return;
 161   }
 162
 163   for (lno=1; fgets(linebuf,sizeof(linebuf),file); lno++) {
 164     l= strlen(linebuf);
 165     if (!l) continue;
 166     if (linebuf[l-1] != '\n' && !feof(file)) {
 167       diag(ads,"%s:%d: line too long",filename,lno);
 168       while ((c= getc(file)) != EOF && c != '\n') { }
 169       if (c == EOF) break;
 170       continue;
 171     }
 172     while (l>0 && whitespace(linebuf[l-1])) l--;
 173     linebuf[l]= 0;
 174     p= linebuf;
 175     while (whitespace(*p)) p++;
 176     if (*p == '#' || *p == '\n') continue;
 177     q= p;
 178     while (*q && !whitespace(*q)) q++;
 179     for (ccip=configcommandinfos;
 180          ccip->name && strncmp(ccip->name,p,q-p);
 181          ccip++);
 182     if (!ccip->name) {
 183       diag(ads,"%s:%d: unknown configuration directive `%.*s'",filename,lno,q-p,p);
 184       continue;
 185     }
 186     while (whitespace(*q)) q++;
 187     ccip->fn(ads,filename,lno,q);
 188   }
 189   if (ferror(file)) {
 190     diag(ads,"%s:%d: read error: %s",filename,lno,strerror(errno));
 191   }
 192   fclose(file);
 193 }
 194
 195 static const char *instrum_getenv(adns_state ads, const char *envvar) {
 196   const char *value;
 197
 198   value= getenv(envvar);
 199   if (!value) debug(ads,"environment variable %s not set",envvar);
 200   else debug(ads,"environment variable %s set to `%s'",envvar,value);
 201   return value;
 202 }
 203
 204 static void readconfigenv(adns_state ads, const char *envvar) {
 205   const char *filename;
 206
 207   if (ads->iflags & adns_if_noenv) {
 208     debug(ads,"not checking environment variable `%s'",envvar);
 209     return;
 210   }
 211   filename= instrum_getenv(ads,envvar);
 212   if (filename) readconfig(ads,filename);
 213 }
 214
 215 int adns_init(adns_state *ads_r, adns_initflags flags) {
 216   adns_state ads;
 217   const char *res_options, *adns_res_options;
 218   struct protoent *proto;
 219   struct sockaddr_in udpaddr;
 220   int udpaddrlen, r;
 221
 222   ads= malloc(sizeof(*ads)); if (!ads) return errno;
 223   ads->input.head= ads->input.tail= 0;
 224   ads->timew.head= ads->timew.tail= 0;
 225   ads->childw.head= ads->childw.tail= 0;
 226   ads->output.head= ads->output.tail= 0;
 227   ads->nextid= 0x311f;
 228   ads->udpsocket= -1;
 229   ads->qbufavail= 0;
 230   ads->qbuf= 0;
 231   ads->tcpbufavail= ads->tcpbufused= ads->tcpbufdone= 0;
 232   ads->tcpbuf= 0;
 233   ads->iflags= flags;
 234   ads->nservers= 0;
 235   ads->iflags= flags;
 236
 237   res_options= instrum_getenv(ads,"RES_OPTIONS");
 238   adns_res_options= instrum_getenv(ads,"ADNS_RES_OPTIONS");
 239   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 240   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 241
 242   readconfig(ads,"/etc/resolv.conf");
 243   readconfigenv(ads,"RES_CONF");
 244   readconfigenv(ads,"ADNS_RES_CONF");
 245
 246   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 247   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 248
 249   ccf_search(ads,"LOCALDOMAIN",-1,instrum_getenv(ads,"LOCALDOMAIN"));
 250   ccf_search(ads,"ADNS_LOCALDOMAIN",-1,instrum_getenv(ads,"ADNS_LOCALDOMAIN"));
 251
 252   if (!ads->nservers) {
 253     struct in_addr ia;
 254     if (ads->iflags & adns_if_debug)
 255       fprintf(stderr,"adns: no nameservers, using localhost\n");
 256     ia.s_addr= INADDR_LOOPBACK;
 257     addserver(ads,ia);
 258   }
 259
 260   proto= getprotobyname("udp"); if (!proto) { r= ENOPROTOOPT; goto x_free; }
 261   ads->udpsocket= socket(AF_INET,SOCK_DGRAM,proto->p_proto);
 262   if (!ads->udpsocket) { r= errno; goto x_closeudp; }
 263
 264   memset(&udpaddr,0,sizeof(udpaddr));
 265   udpaddr.sin_family= AF_INET;
 266   udpaddr.sin_addr.s_addr= INADDR_ANY;
 267   udpaddr.sin_port= 0;
 268   r= bind(ads->udpsocket,&udpaddr,sizeof(udpaddr));
 269   if (r) { r= errno; goto x_closeudp; }
 270
 271   udpaddrlen= sizeof(udpaddr);
 272   r= getsockname(ads->udpsocket,&udpaddr,&udpaddrlen);
 273   if (r) { r= errno; goto x_closeudp; }
 274   if (udpaddr.sin_family != AF_INET) {
 275     diag(ads,"network API error: UDP socket not AF_INET but %lu",
 276          (unsigned long)udpaddr.sin_family);
 277     r= EPROTOTYPE; goto x_closeudp;
 278   }
 279   debug(ads,"UDP socket is %s:%u",inet_ntoa(udpaddr.sin_addr),ntohs(udpaddr.sin_port));
 280
 281   *ads_r= ads;
 282   return 0;
 283
 284  x_closeudp:
 285   close(ads->udpsocket);
 286  x_free:
 287   free(ads);
 288   return r;
 289 }
 290
 291 static void query_fail(adns_state ads, adns_query qu, adns_status stat) {
 292   adns_answer *ans;
 293
 294   ans= qu->answer;
 295   if (!ans) ans= malloc(sizeof(*qu->answer));
 296   if (ans) {
 297     ans->status= stat;
 298     ans->cname= 0;
 299     ans->type= qu->type;
 300     ans->nrrs= 0;
 301   }
 302   qu->answer= ans;
 303   LIST_LINK_TAIL(ads->input,qu);
 304 }
 305
 306 int adns_finish(adns_state ads) {
 307   abort(); /* FIXME */
 308 }
 309
 310 void adns_interest(adns_state ads, int *maxfd,
 311                    fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 312                    struct timeval **tv_io, struct timeval *tvbuf) {
 313   abort(); /* FIXME */
 314 }
 315
 316 static void autosys(adns_state ads) {
 317   if (ads->iflags & adns_if_noautosys) return;
 318   adns_callback(ads,-1,0,0,0);
 319 }
 320
 321 void adns_cancel(adns_state ads, adns_query query) {
 322   abort(); /* FIXME */
 323 }
 324
 325 int adns_callback(adns_state ads, int maxfd,
 326                   const fd_set *readfds, const fd_set *writefds,
 327                   const fd_set *exceptfds) {
 328   abort(); /* FIXME */
 329 }
 330
 331 static int internal_check(adns_state ads,
 332                           adns_query *query_io,
 333                           adns_answer *answer,
 334                           void *context_r) {
 335   abort(); /* FIXME */
 336 }
 337
 338 int adns_wait(adns_state ads,
 339               adns_query *query_io,
 340               adns_answer *answer,
 341               void *context_r) {
 342   int r, maxfd, rsel, rcb;
 343   fd_set readfds, writefds, exceptfds;
 344   struct timeval tvbuf, *tvp;
 345
 346   for (;;) {
 347     r= internal_check(ads,query_io,answer,context_r);
 348     if (r && r != EWOULDBLOCK) return r;
 349     FD_ZERO(&readfds); FD_ZERO(&writefds); FD_ZERO(&exceptfds);
 350     maxfd= 0; tvp= 0;
 351     adns_interest(ads,&maxfd,&readfds,&writefds,&exceptfds,&tvp,&tvbuf);
 352     rsel= select(maxfd,&readfds,&writefds,&exceptfds,tvp);
 353     if (rsel==-1) return r;
 354     rcb= adns_callback(ads,maxfd,&readfds,&writefds,&exceptfds);
 355     assert(rcb==rsel);
 356   }
 357 }
 358
 359 int adns_check(adns_state ads,
 360                adns_query *query_io,
 361                adns_answer *answer,
 362                void *context_r) {
 363   autosys(ads);
 364   return internal_check(ads,query_io,answer,context_r);
 365 }
 366
 367 int adns_synchronous(adns_state ads,
 368                      const char *owner,
 369                      adns_rrtype type,
 370                      adns_queryflags flags,
 371                      adns_answer *answer) {
 372   adns_query qu;
 373   int r;
 374
 375   r= adns_submit(ads,owner,type,flags,0,&qu);
 376   if (r) return r;
 377
 378   do {
 379     r= adns_wait(ads,&qu,answer,0);
 380   } while (r==EINTR);
 381   if (r) adns_cancel(ads,qu);
 382   return r;
 383 }
 384
 385 static int mkquery(adns_state ads,
 386                    const char *owner,
 387                    adns_rrtype type) {
 388   abort();
 389 }
 390
 391 int adns_submit(adns_state ads,
 392                 const char *owner,
 393                 adns_rrtype type,
 394                 adns_queryflags flags,
 395                 void *context,
 396                 adns_query *query_r) {
 397   adns_query qu;
 398   adns_status stat;
 399   int ol;
 400
 401   stat= 0;
 402   ol= strlen(owner);
 403   if (ol>MAXDNAME+1) { stat= adns_s_invaliddomain; ol= 0; }
 404   if (ol>0 && owner[ol-1]=='.') { flags &= ~adns_f_search; ol--; }
 405   qu= malloc(sizeof(*qu)+ol+1); if (!qu) return errno;
 406   qu->next= qu->back= qu->parent= qu->child= 0;
 407   qu->id= ads->nextid++;
 408   qu->type= type;
 409   qu->answer= 0;
 410   qu->flags= flags;
 411   qu->context= context;
 412   qu->udpretries= 0;
 413   qu->sentudp= qu->senttcp= 0;
 414   qu->nextserver= 0;
 415   memcpy(qu->owner,owner,ol); qu->owner[ol]= 0;
 416
 417
 418   mkquery(ads,owner,type);
 419
 420   if (stat) {
 421     query_fail(ads,qu,stat);
 422   } else {
 423     LIST_LINK_TAIL(ads->input,qu);
 424     autosys(ads);
 425   }
 426   *query_r= qu;
 427   return 0;
 428 }