dname.c
Go to the documentation of this file.
00001 /*
00002  * dname.c
00003  *
00004  * dname specific rdata implementations
00005  * A dname is a rdf structure with type LDNS_RDF_TYPE_DNAME
00006  * It is not a /real/ type! All function must therefor check
00007  * for LDNS_RDF_TYPE_DNAME.
00008  *
00009  * a Net::DNS like library for C
00010  *
00011  * (c) NLnet Labs, 2004-2006
00012  *
00013  * See the file LICENSE for the license
00014  */
00015 
00016 #include <ldns/config.h>
00017 
00018 #include <ldns/ldns.h>
00019 
00020 #ifdef HAVE_NETINET_IN_H
00021 #include <netinet/in.h>
00022 #endif
00023 #ifdef HAVE_SYS_SOCKET_H
00024 #include <sys/socket.h>
00025 #endif
00026 #ifdef HAVE_NETDB_H
00027 #include <netdb.h>
00028 #endif
00029 #ifdef HAVE_ARPA_INET_H
00030 #include <arpa/inet.h>
00031 #endif
00032 
00033 ldns_rdf *
00034 ldns_dname_cat_clone(const ldns_rdf *rd1, const ldns_rdf *rd2)
00035 {
00036         ldns_rdf *new;
00037         uint16_t new_size;
00038         uint8_t *buf;
00039         uint16_t left_size;
00040 
00041         if (ldns_rdf_get_type(rd1) != LDNS_RDF_TYPE_DNAME ||
00042                         ldns_rdf_get_type(rd2) != LDNS_RDF_TYPE_DNAME) {
00043                 return NULL;
00044         }
00045 
00046         /* remove root label if it is present at the end of the left
00047          * rd, by reducing the size with 1
00048          */
00049         left_size = ldns_rdf_size(rd1);
00050         if (left_size > 0 &&ldns_rdf_data(rd1)[left_size - 1] == 0) {
00051                 left_size--;
00052         }
00053 
00054         /* we overwrite the nullbyte of rd1 */
00055         new_size = left_size + ldns_rdf_size(rd2);
00056         buf = LDNS_XMALLOC(uint8_t, new_size);
00057         if (!buf) {
00058                 return NULL;
00059         }
00060 
00061         /* put the two dname's after each other */
00062         memcpy(buf, ldns_rdf_data(rd1), left_size);
00063         memcpy(buf + left_size, ldns_rdf_data(rd2), ldns_rdf_size(rd2));
00064 
00065         new = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, new_size, buf);
00066 
00067         LDNS_FREE(buf);
00068         return new;
00069 }
00070 
00071 ldns_status
00072 ldns_dname_cat(ldns_rdf *rd1, ldns_rdf *rd2)
00073 {
00074         uint16_t left_size;
00075         uint16_t size;
00076         uint8_t* newd;
00077 
00078         if (ldns_rdf_get_type(rd1) != LDNS_RDF_TYPE_DNAME ||
00079                         ldns_rdf_get_type(rd2) != LDNS_RDF_TYPE_DNAME) {
00080                 return LDNS_STATUS_ERR;
00081         }
00082 
00083         /* remove root label if it is present at the end of the left
00084          * rd, by reducing the size with 1
00085          */
00086         left_size = ldns_rdf_size(rd1);
00087         if (left_size > 0 &&ldns_rdf_data(rd1)[left_size - 1] == 0) {
00088                 left_size--;
00089         }
00090 
00091         size = left_size + ldns_rdf_size(rd2);
00092         newd = LDNS_XREALLOC(ldns_rdf_data(rd1), uint8_t, size);
00093         if(!newd) {
00094                 return LDNS_STATUS_MEM_ERR;
00095         }
00096 
00097         ldns_rdf_set_data(rd1, newd);
00098         memcpy(ldns_rdf_data(rd1) + left_size, ldns_rdf_data(rd2),
00099                         ldns_rdf_size(rd2));
00100         ldns_rdf_set_size(rd1, size);
00101 
00102         return LDNS_STATUS_OK;
00103 }
00104 
00105 ldns_rdf *
00106 ldns_dname_reverse(const ldns_rdf *d)
00107 {
00108         ldns_rdf *new;
00109         ldns_rdf *tmp;
00110         ldns_rdf *d_tmp;
00111         ldns_status status;
00112 
00113         d_tmp = ldns_rdf_clone(d);
00114 
00115         new = ldns_dname_new_frm_str(".");
00116         if(!new)
00117                 return NULL;
00118 
00119         while(ldns_dname_label_count(d_tmp) > 0) {
00120                 tmp = ldns_dname_label(d_tmp, 0);
00121                 status = ldns_dname_cat(tmp, new);
00122                 if(status != LDNS_STATUS_OK) {
00123                         ldns_rdf_deep_free(new);
00124                         ldns_rdf_deep_free(d_tmp);
00125                         return NULL;
00126                 }
00127                 ldns_rdf_deep_free(new);
00128                 new = tmp;
00129                 tmp = ldns_dname_left_chop(d_tmp);
00130                 ldns_rdf_deep_free(d_tmp);
00131                 d_tmp = tmp;
00132         }
00133         ldns_rdf_deep_free(d_tmp);
00134 
00135         return new;
00136 }
00137 
00138 ldns_rdf *
00139 ldns_dname_clone_from(const ldns_rdf *d, uint16_t n)
00140 {
00141         uint8_t *data;
00142         uint8_t label_size;
00143         size_t data_size;
00144 
00145         if (!d ||
00146             ldns_rdf_get_type(d) != LDNS_RDF_TYPE_DNAME ||
00147             ldns_dname_label_count(d) < n) {
00148                 return NULL;
00149         }
00150 
00151         data = ldns_rdf_data(d);
00152         data_size = ldns_rdf_size(d);
00153         while (n > 0) {
00154                 label_size = data[0] + 1;
00155                 data += label_size;
00156                 if (data_size < label_size) {
00157                         /* this label is very broken */
00158                         return NULL;
00159                 }
00160                 data_size -= label_size;
00161                 n--;
00162         }
00163 
00164         return ldns_dname_new_frm_data(data_size, data);
00165 }
00166 
00167 ldns_rdf *
00168 ldns_dname_left_chop(const ldns_rdf *d)
00169 {
00170         uint8_t label_pos;
00171         ldns_rdf *chop;
00172 
00173         if (!d) {
00174                 return NULL;
00175         }
00176 
00177         if (ldns_rdf_get_type(d) != LDNS_RDF_TYPE_DNAME) {
00178                 return NULL;
00179         }
00180         if (ldns_dname_label_count(d) == 0) {
00181                 /* root label */
00182                 return NULL;
00183         }
00184         /* 05blaat02nl00 */
00185         label_pos = ldns_rdf_data(d)[0];
00186 
00187         chop = ldns_dname_new_frm_data(ldns_rdf_size(d) - label_pos - 1,
00188                         ldns_rdf_data(d) + label_pos + 1);
00189         return chop;
00190 }
00191 
00192 uint8_t
00193 ldns_dname_label_count(const ldns_rdf *r)
00194 {
00195         uint16_t src_pos;
00196         uint16_t len;
00197         uint8_t i;
00198         size_t r_size;
00199 
00200         if (!r) {
00201                 return 0;
00202         }
00203 
00204         i = 0;
00205         src_pos = 0;
00206         r_size = ldns_rdf_size(r);
00207 
00208         if (ldns_rdf_get_type(r) != LDNS_RDF_TYPE_DNAME) {
00209                 return 0;
00210         } else {
00211                 len = ldns_rdf_data(r)[src_pos]; /* start of the label */
00212 
00213                 /* single root label */
00214                 if (1 == r_size) {
00215                         return 0;
00216                 } else {
00217                         while ((len > 0) && src_pos < r_size) {
00218                                 src_pos++;
00219                                 src_pos += len;
00220                                 len = ldns_rdf_data(r)[src_pos];
00221                                 i++;
00222                         }
00223                 }
00224         }
00225         return i;
00226 }
00227 
00228 ldns_rdf *
00229 ldns_dname_new(uint16_t s, void *d)
00230 {
00231         ldns_rdf *rd;
00232 
00233         rd = LDNS_MALLOC(ldns_rdf);
00234         if (!rd) {
00235                 return NULL;
00236         }
00237         ldns_rdf_set_size(rd, s);
00238         ldns_rdf_set_type(rd, LDNS_RDF_TYPE_DNAME);
00239         ldns_rdf_set_data(rd, d);
00240         return rd;
00241 }
00242 
00243 ldns_rdf *
00244 ldns_dname_new_frm_str(const char *str)
00245 {
00246         return ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, str);
00247 }
00248 
00249 ldns_rdf *
00250 ldns_dname_new_frm_data(uint16_t size, const void *data)
00251 {
00252         return ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, size, data);
00253 }
00254 
00255 void
00256 ldns_dname2canonical(const ldns_rdf *rd)
00257 {
00258         uint8_t *rdd;
00259         uint16_t i;
00260 
00261         if (ldns_rdf_get_type(rd) != LDNS_RDF_TYPE_DNAME) {
00262                 return;
00263         }
00264 
00265         rdd = (uint8_t*)ldns_rdf_data(rd);
00266         for (i = 0; i < ldns_rdf_size(rd); i++, rdd++) {
00267                 *rdd = (uint8_t)LDNS_DNAME_NORMALIZE((int)*rdd);
00268         }
00269 }
00270 
00271 bool
00272 ldns_dname_is_subdomain(const ldns_rdf *sub, const ldns_rdf *parent)
00273 {
00274         uint8_t sub_lab;
00275         uint8_t par_lab;
00276         int8_t i, j;
00277         ldns_rdf *tmp_sub = NULL;
00278         ldns_rdf *tmp_par = NULL;
00279     ldns_rdf *sub_clone;
00280     ldns_rdf *parent_clone;
00281     bool result = true;
00282 
00283         if (ldns_rdf_get_type(sub) != LDNS_RDF_TYPE_DNAME ||
00284                         ldns_rdf_get_type(parent) != LDNS_RDF_TYPE_DNAME ||
00285                         ldns_rdf_compare(sub, parent) == 0) {
00286                 return false;
00287         }
00288 
00289     /* would be nicer if we do not have to clone... */
00290     sub_clone = ldns_dname_clone_from(sub, 0);
00291     parent_clone = ldns_dname_clone_from(parent, 0);
00292     ldns_dname2canonical(sub_clone);
00293     ldns_dname2canonical(parent_clone);
00294 
00295         sub_lab = ldns_dname_label_count(sub_clone);
00296         par_lab = ldns_dname_label_count(parent_clone);
00297 
00298         /* if sub sits above parent, it cannot be a child/sub domain */
00299         if (sub_lab < par_lab) {
00300                 result = false;
00301         } else {
00302                 /* check all labels the from the parent labels, from right to left.
00303                  * When they /all/ match we have found a subdomain
00304                  */
00305                 j = sub_lab - 1; /* we count from zero, thank you */
00306                 for (i = par_lab -1; i >= 0; i--) {
00307                         tmp_sub = ldns_dname_label(sub_clone, j);
00308                         tmp_par = ldns_dname_label(parent_clone, i);
00309                         if (!tmp_sub || !tmp_par) {
00310                                 /* deep free does null check */
00311                                 ldns_rdf_deep_free(tmp_sub);
00312                                 ldns_rdf_deep_free(tmp_par);
00313                                 result = false;
00314                                 break;
00315                         }
00316 
00317                         if (ldns_rdf_compare(tmp_sub, tmp_par) != 0) {
00318                                 /* they are not equal */
00319                                 ldns_rdf_deep_free(tmp_sub);
00320                                 ldns_rdf_deep_free(tmp_par);
00321                                 result = false;
00322                                 break;
00323                         }
00324                         ldns_rdf_deep_free(tmp_sub);
00325                         ldns_rdf_deep_free(tmp_par);
00326                         j--;
00327                 }
00328         }
00329         ldns_rdf_deep_free(sub_clone);
00330         ldns_rdf_deep_free(parent_clone);
00331         return result;
00332 }
00333 
00334 int
00335 ldns_dname_compare(const ldns_rdf *dname1, const ldns_rdf *dname2)
00336 {
00337         size_t lc1, lc2, lc1f, lc2f;
00338         size_t i;
00339         int result = 0;
00340         uint8_t *lp1, *lp2;
00341 
00342         /* see RFC4034 for this algorithm */
00343         /* this algorithm assumes the names are normalized to case */
00344 
00345         /* only when both are not NULL we can say anything about them */
00346         if (!dname1 && !dname2) {
00347                 return 0;
00348         }
00349         if (!dname1 || !dname2) {
00350                 return -1;
00351         }
00352         /* asserts must happen later as we are looking in the
00353          * dname, which could be NULL. But this case is handled
00354          * above
00355          */
00356         assert(ldns_rdf_get_type(dname1) == LDNS_RDF_TYPE_DNAME);
00357         assert(ldns_rdf_get_type(dname2) == LDNS_RDF_TYPE_DNAME);
00358 
00359         lc1 = ldns_dname_label_count(dname1);
00360         lc2 = ldns_dname_label_count(dname2);
00361 
00362         if (lc1 == 0 && lc2 == 0) {
00363                 return 0;
00364         }
00365         if (lc1 == 0) {
00366                 return -1;
00367         }
00368         if (lc2 == 0) {
00369                 return 1;
00370         }
00371         lc1--;
00372         lc2--;
00373         /* we start at the last label */
00374         while (true) {
00375                 /* find the label first */
00376                 lc1f = lc1;
00377                 lp1 = ldns_rdf_data(dname1);
00378                 while (lc1f > 0) {
00379                         lp1 += *lp1 + 1;
00380                         lc1f--;
00381                 }
00382 
00383                 /* and find the other one */
00384                 lc2f = lc2;
00385                 lp2 = ldns_rdf_data(dname2);
00386                 while (lc2f > 0) {
00387                         lp2 += *lp2 + 1;
00388                         lc2f--;
00389                 }
00390 
00391                 /* now check the label character for character. */
00392                 for (i = 1; i < (size_t)(*lp1 + 1); i++) {
00393                         if (i > *lp2) {
00394                                 /* apparently label 1 is larger */
00395                                 result = 1;
00396                                 goto done;
00397                         }
00398                         if (LDNS_DNAME_NORMALIZE((int) *(lp1 + i)) <
00399                             LDNS_DNAME_NORMALIZE((int) *(lp2 + i))) {
00400                             result = -1;
00401                             goto done;
00402                         } else if (LDNS_DNAME_NORMALIZE((int) *(lp1 + i)) >
00403                             LDNS_DNAME_NORMALIZE((int) *(lp2 + i))) {
00404                             result = 1;
00405                             goto done;
00406                         }
00407                 }
00408                 if (*lp1 < *lp2) {
00409                         /* apparently label 2 is larger */
00410                         result = -1;
00411                         goto done;
00412                 }
00413                 if (lc1 == 0 && lc2 > 0) {
00414                         result = -1;
00415                         goto done;
00416                 } else if (lc1 > 0 && lc2 == 0) {
00417                         result = 1;
00418                         goto done;
00419                 } else if (lc1 == 0 && lc2 == 0) {
00420                         result = 0;
00421                         goto done;
00422                 }
00423                 lc1--;
00424                 lc2--;
00425         }
00426 
00427         done:
00428         return result;
00429 }
00430 
00431 int
00432 ldns_dname_is_wildcard(const ldns_rdf* dname)
00433 {
00434         return ( ldns_dname_label_count(dname) > 0 &&
00435                  ldns_rdf_data(dname)[0] == 1 &&
00436                  ldns_rdf_data(dname)[1] == '*');
00437 }
00438 
00439 int
00440 ldns_dname_match_wildcard(const ldns_rdf *dname, const ldns_rdf *wildcard)
00441 {
00442         ldns_rdf *wc_chopped;
00443         int result;
00444         /* check whether it really is a wildcard */
00445         if (ldns_dname_is_wildcard(wildcard)) {
00446                 /* ok, so the dname needs to be a subdomain of the wildcard
00447                  * without the *
00448                  */
00449                 wc_chopped = ldns_dname_left_chop(wildcard);
00450                 result = (int) ldns_dname_is_subdomain(dname, wc_chopped);
00451                 ldns_rdf_deep_free(wc_chopped);
00452         } else {
00453                 result = (ldns_dname_compare(dname, wildcard) == 0);
00454         }
00455         return result;
00456 }
00457 
00458 /* nsec test: does prev <= middle < next
00459  * -1 = yes
00460  * 0 = error/can't tell
00461  * 1 = no
00462  */
00463 int
00464 ldns_dname_interval(const ldns_rdf *prev, const ldns_rdf *middle,
00465                 const ldns_rdf *next)
00466 {
00467         int prev_check, next_check;
00468 
00469         assert(ldns_rdf_get_type(prev) == LDNS_RDF_TYPE_DNAME);
00470         assert(ldns_rdf_get_type(middle) == LDNS_RDF_TYPE_DNAME);
00471         assert(ldns_rdf_get_type(next) == LDNS_RDF_TYPE_DNAME);
00472 
00473         prev_check = ldns_dname_compare(prev, middle);
00474         next_check = ldns_dname_compare(middle, next);
00475         /* <= next. This cannot be the case for nsec, because then we would
00476          * have gotten the nsec of next...
00477          */
00478         if (next_check == 0) {
00479                 return 0;
00480         }
00481 
00482                         /* <= */
00483         if ((prev_check == -1 || prev_check == 0) &&
00484                         /* < */
00485                         next_check == -1) {
00486                 return -1;
00487         } else {
00488                 return 1;
00489         }
00490 }
00491 
00492 
00493 bool
00494 ldns_dname_str_absolute(const char *dname_str)
00495 {
00496         const char* s;
00497         if(dname_str && strcmp(dname_str, ".") == 0)
00498                 return 1;
00499         if(!dname_str || strlen(dname_str) < 2)
00500                 return 0;
00501         if(dname_str[strlen(dname_str) - 1] != '.')
00502                 return 0;
00503         if(dname_str[strlen(dname_str) - 2] != '\\')
00504                 return 1; /* ends in . and no \ before it */
00505         /* so we have the case of ends in . and there is \ before it */
00506         for(s=dname_str; *s; s++) {
00507                 if(*s == '\\') {
00508                         if(s[1] && s[2] && s[3] /* check length */
00509                                 && isdigit(s[1]) && isdigit(s[2]) && 
00510                                 isdigit(s[3]))
00511                                 s += 3;
00512                         else if(!s[1] || isdigit(s[1])) /* escape of nul,0-9 */
00513                                 return 0; /* parse error */
00514                         else s++; /* another character escaped */
00515                 }
00516                 else if(!*(s+1) && *s == '.')
00517                         return 1; /* trailing dot, unescaped */
00518         }
00519         return 0;
00520 }
00521 
00522 ldns_rdf *
00523 ldns_dname_label(const ldns_rdf *rdf, uint8_t labelpos)
00524 {
00525         uint8_t labelcnt;
00526         uint16_t src_pos;
00527         uint16_t len;
00528         ldns_rdf *tmpnew;
00529         size_t s;
00530         uint8_t *data;
00531 
00532         if (ldns_rdf_get_type(rdf) != LDNS_RDF_TYPE_DNAME) {
00533                 return NULL;
00534         }
00535 
00536         labelcnt = 0;
00537         src_pos = 0;
00538         s = ldns_rdf_size(rdf);
00539 
00540         len = ldns_rdf_data(rdf)[src_pos]; /* label start */
00541         while ((len > 0) && src_pos < s) {
00542                 if (labelcnt == labelpos) {
00543                         /* found our label */
00544                         data = LDNS_XMALLOC(uint8_t, len + 2);
00545                         if (!data) {
00546                                 return NULL;
00547                         }
00548                         memcpy(data, ldns_rdf_data(rdf) + src_pos, len + 1);
00549                         data[len + 2 - 1] = 0;
00550 
00551                         tmpnew = ldns_rdf_new( LDNS_RDF_TYPE_DNAME
00552                                              , len + 2, data);
00553                         if (!tmpnew) {
00554                                 LDNS_FREE(data);
00555                                 return NULL;
00556                         }
00557                         return tmpnew;
00558                 }
00559                 src_pos++;
00560                 src_pos += len;
00561                 len = ldns_rdf_data(rdf)[src_pos];
00562                 labelcnt++;
00563         }
00564         return NULL;
00565 }