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
   9 #include <arpa/nameser.h>
  10 #include <sys/socket.h>
  11 #include <netinet/in.h>
  12 #include <arpa/inet.h>
  13
  14 #include "adns-internal.h"
  15
  16 #define LIST_UNLINK(list,node) \
  17   do { \
  18     if ((node)->back) (node)->back->next= (node)->next; \
  19       else                   (list).head= (node)->next; \
  20     if ((node)->next) (node)->next->back= (node)->back; \
  21       else                   (list).tail= (node)->back; \
  22   } while(0)
  23
  24 #define LIST_LINK_TAIL(list,node) \
  25   do { \
  26     (node)->back= 0; \
  27     (node)->next= (list).tail; \
  28     if ((list).tail) (list).tail->back= (node); else (list).head= (node); \
  29     (list).tail= (node); \
  30   } while(0)
  31
  32 static void vdebug(adns_state ads, const char *fmt, va_list al) {
  33   if (!(ads->iflags & adns_if_debug)) return;
  34   fputs("adns debug: ",stderr);
  35   vfprintf(stderr,fmt,al);
  36   fputc('\n',stderr);
  37 }
  38
  39 static void debug(adns_state ads, const char *fmt, ...) {
  40   va_list al;
  41
  42   va_start(al,fmt);
  43   vdebug(ads,fmt,al);
  44   va_end(al);
  45 }
  46
  47 static void vdiag(adns_state ads, const char *fmt, va_list al) {
  48   if (ads->iflags & adns_if_noerrprint) return;
  49   fputs("adns: ",stderr);
  50   vfprintf(stderr,fmt,al);
  51   fputc('\n',stderr);
  52 }
  53
  54 static void diag(adns_state ads, const char *fmt, ...) {
  55   va_list al;
  56
  57   va_start(al,fmt);
  58   vdiag(ads,fmt,al);
  59   va_end(al);
  60 }
  61
  62 static void addserver(adns_state ads, struct in_addr addr) {
  63   if (ads->nservers>=MAXSERVERS) {
  64     diag(ads,"too many nameservers, ignoring %s",inet_ntoa(addr));
  65   } else {
  66     ads->servers[ads->nservers].addr= addr;
  67     ads->servers[ads->nservers].tcpsocket= -1;
  68     ads->nservers++;
  69   }
  70 }
  71
  72 static void configparseerr(adns_state ads, const char *fn, int lno,
  73                            const char *fmt, ...) {
  74   va_list al;
  75
  76   if (ads->iflags & adns_if_noerrprint) return;
  77   if (lno==-1) fprintf(stderr,"adns: %s: ",fn);
  78   else fprintf(stderr,"adns: %s:%d: ",fn,lno);
  79   va_start(al,fmt);
  80   vfprintf(stderr,fmt,al);
  81   va_end(al);
  82   fputc('\n',stderr);
  83 }
  84
  85 static void ccf_nameserver(adns_state ads, const char *fn, int lno, const char *buf) {
  86   struct in_addr ia;
  87
  88   if (!inet_aton(buf,&ia)) {
  89     configparseerr(ads,fn,lno,"invalid nameserver address `%s'",buf);
  90     return;
  91   }
  92   debug(ads,"using nameserver %s",inet_ntoa(ia));
  93   addserver(ads,ia);
  94 }
  95
  96 static void ccf_search(adns_state ads, const char *fn, int lno, const char *buf) {
  97   if (!buf) return;
  98   diag(ads,"warning - `search' ignored FIXME");
  99 }
 100
 101 static void ccf_sortlist(adns_state ads, const char *fn, int lno, const char *buf) {
 102   diag(ads,"warning - `sortlist' ignored FIXME");
 103 }
 104
 105 static void ccf_options(adns_state ads, const char *fn, int lno, const char *buf) {
 106   if (!buf) return;
 107   diag(ads,"warning - `options' ignored FIXME");
 108 }
 109
 110 static void ccf_clearnss(adns_state ads, const char *fn, int lno, const char *buf) {
 111   ads->nservers= 0;
 112 }
 113
 114 static const struct configcommandinfo {
 115   const char *name;
 116   void (*fn)(adns_state ads, const char *fn, int lno, const char *buf);
 117 } configcommandinfos[]= {
 118   { "nameserver",        ccf_nameserver  },
 119   { "domain",            ccf_search      },
 120   { "search",            ccf_search      },
 121   { "sortlist",          ccf_sortlist    },
 122   { "options",           ccf_options     },
 123   { "clearnameservers",  ccf_clearnss    },
 124   {  0                                   }
 125 };
 126
 127 static int whitespace(int c) {
 128   return c==' ' || c=='\n' || c=='\t';
 129 }
 130
 131 static void readconfig(adns_state ads, const char *filename) {
 132   char linebuf[2000], *p, *q;
 133   FILE *file;
 134   int lno, l, c;
 135   const struct configcommandinfo *ccip;
 136
 137   file= fopen(filename,"r");
 138   if (!file) {
 139     if (errno == ENOENT) {
 140       debug(ads,"configuration file `%s' does not exist",filename);
 141       return;
 142     }
 143     diag(ads,"cannot open configuration file `%s': %s",filename,strerror(errno));
 144     return;
 145   }
 146
 147   for (lno=1; fgets(linebuf,sizeof(linebuf),file); lno++) {
 148     l= strlen(linebuf);
 149     if (!l) continue;
 150     if (linebuf[l-1] != '\n' && !feof(file)) {
 151       diag(ads,"%s:%d: line too long",filename,lno);
 152       while ((c= getc(file)) != EOF && c != '\n') { }
 153       if (c == EOF) break;
 154       continue;
 155     }
 156     while (l>0 && whitespace(linebuf[l-1])) l--;
 157     linebuf[l]= 0;
 158     p= linebuf;
 159     while (whitespace(*p)) p++;
 160     if (*p == '#' || *p == '\n') continue;
 161     q= p;
 162     while (*q && !whitespace(*q)) q++;
 163     for (ccip=configcommandinfos;
 164          ccip->name && strncmp(ccip->name,p,q-p);
 165          ccip++);
 166     if (!ccip->name) {
 167       diag(ads,"%s:%d: unknown configuration directive `%.*s'",filename,lno,q-p,p);
 168       continue;
 169     }
 170     while (whitespace(*q)) q++;
 171     ccip->fn(ads,filename,lno,q);
 172   }
 173   if (ferror(file)) {
 174     diag(ads,"%s:%d: read error: %s",filename,lno,strerror(errno));
 175   }
 176   fclose(file);
 177 }
 178
 179 static const char *instrum_getenv(adns_state ads, const char *envvar) {
 180   const char *value;
 181
 182   value= getenv(envvar);
 183   if (!value) debug(ads,"environment variable `%s' not set",envvar);
 184   else debug(ads,"environment variable `%s' set to `%s'",envvar,value);
 185   return value;
 186 }
 187
 188 static void readconfigenv(adns_state ads, const char *envvar) {
 189   const char *filename;
 190
 191   if (ads->iflags & adns_if_noenv) {
 192     debug(ads,"not checking environment variable `%s'",envvar);
 193     return;
 194   }
 195   filename= instrum_getenv(ads,envvar);
 196   if (filename) readconfig(ads,filename);
 197 }
 198
 199 int adns_init(adns_state *ads_r, adns_initflags flags) {
 200   adns_state ads;
 201   const char *res_options, *adns_res_options;
 202
 203   ads= malloc(sizeof(*ads)); if (!ads) return errno;
 204   ads->input.head= ads->input.tail= 0;
 205   ads->timew.head= ads->timew.tail= 0;
 206   ads->childw.head= ads->childw.tail= 0;
 207   ads->output.head= ads->output.tail= 0;
 208   ads->udpsocket= -1;
 209   ads->qbufavail= 0;
 210   ads->qbuf= 0;
 211   ads->tcpbufavail= ads->tcpbufused= ads->tcpbufdone= 0;
 212   ads->tcpbuf= 0;
 213   ads->iflags= flags;
 214   ads->nservers= 0;
 215   ads->iflags= flags;
 216
 217   res_options= instrum_getenv(ads,"RES_OPTIONS");
 218   adns_res_options= instrum_getenv(ads,"ADNS_RES_OPTIONS");
 219   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 220   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 221
 222   readconfig(ads,"/etc/resolv.conf");
 223   readconfigenv(ads,"RES_CONF");
 224   readconfigenv(ads,"ADNS_RES_CONF");
 225
 226   ccf_options(ads,"RES_OPTIONS",-1,res_options);
 227   ccf_options(ads,"ADNS_RES_OPTIONS",-1,adns_res_options);
 228
 229   ccf_search(ads,"LOCALDOMAIN",-1,instrum_getenv(ads,"LOCALDOMAIN"));
 230   ccf_search(ads,"ADNS_LOCALDOMAIN",-1,instrum_getenv(ads,"ADNS_LOCALDOMAIN"));
 231
 232   if (!ads->nservers) {
 233     struct in_addr ia;
 234     if (ads->iflags & adns_if_debug)
 235       fprintf(stderr,"adns: no nameservers, using localhost\n");
 236     ia.s_addr= INADDR_LOOPBACK;
 237     addserver(ads,ia);
 238   }
 239
 240   *ads_r= ads;
 241   return 0;
 242 }
 243
 244 static void query_fail(adns_state ads, adns_query qu, adns_status stat) {
 245   struct adns_answer *ans;
 246
 247   ans= qu->answer;
 248   if (!ans) ans= malloc(sizeof(*qu->answer));
 249   if (ans) {
 250     ans->status= stat;
 251     ans->cname= 0;
 252     ans->type= qu->type;
 253     ans->nrrs= 0;
 254   }
 255   qu->answer= ans;
 256   LIST_LINK_TAIL(ads->input,qu);
 257 }
 258
 259 void adns_interest(adns_state ads,
 260                    fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 261                    int *maxfd, struct timeval **tv_io, struct timeval *tvbuf) {
 262   abort(); /* FIXME */
 263 }
 264
 265 int adns_submit(adns_state ads,
 266                 const char *owner,
 267                 adns_rrtype type,
 268                 int flags,
 269                 void *context,
 270                 adns_query *query_r) {
 271   adns_query qu;
 272   adns_status stat;
 273   int ol;
 274
 275   stat= 0;
 276   ol= strlen(owner);
 277   if (ol>MAXDNAME+1) { stat= adns_s_invaliddomain; ol= 0; }
 278   if (ol>0 && owner[ol-1]=='.') { flags &= ~adns_f_search; ol--; }
 279   qu= malloc(sizeof(*qu)+ol+1); if (!qu) return errno;
 280   qu->next= qu->back= qu->parent= qu->child= 0;
 281   qu->type= type;
 282   qu->answer= 0;
 283   qu->flags= flags;
 284   qu->context= context;
 285   qu->udpretries= 0;
 286   qu->server= 0;
 287   memcpy(qu->owner,owner,ol); qu->owner[ol]= 0;
 288   if (stat) {
 289     query_fail(ads,qu,stat);
 290   } else {
 291     LIST_LINK_TAIL(ads->input,qu);
 292     adns_interest(ads,0,0,0,0,0,0);
 293   }
 294   *query_r= qu;
 295
 296   abort(); /* FIXME */
 297 }