| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Background reverse name resolution (ADNS version) |
| 4 | * |
| 5 | * (c) 2003 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the mLib utilities library. |
| 11 | * |
| 12 | * mLib is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * mLib is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with mLib; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | * |
| 27 | * |
| 28 | * HOWEVER, since GNU adns is covered by the full GNU General Public |
| 29 | * License, this file (only) is also covered by the full GNU GPL, and |
| 30 | * you may NOT take advantage of the more liberal conditions of the |
| 31 | * LGPL when modifying or redistributing this file. This doesn't mean |
| 32 | * that a program which uses the interface provided by this file is |
| 33 | * covered by the GPL, since @bres.c@ provides the same interface and |
| 34 | * is LGPL. However, it does mean that if your program depends, for |
| 35 | * some reason (e.g., to meet particular performance criteria), on |
| 36 | * this adns-based implementation of mLib's background resolver then it |
| 37 | * must be licensed under the full GPL. |
| 38 | */ |
| 39 | |
| 40 | #include "config.h" |
| 41 | |
| 42 | #ifndef HAVE_ADNS |
| 43 | # error "You need the ADNS library to compile this file." |
| 44 | #endif |
| 45 | |
| 46 | /*----- Header files ------------------------------------------------------*/ |
| 47 | |
| 48 | #include <assert.h> |
| 49 | #include <errno.h> |
| 50 | #include <signal.h> |
| 51 | #include <stdio.h> |
| 52 | #include <stdlib.h> |
| 53 | #include <string.h> |
| 54 | |
| 55 | #include <sys/types.h> |
| 56 | #include <sys/time.h> |
| 57 | #include <unistd.h> |
| 58 | #include <sys/wait.h> |
| 59 | |
| 60 | #include <sys/socket.h> |
| 61 | #include <netinet/in.h> |
| 62 | #include <arpa/inet.h> |
| 63 | #include <netdb.h> |
| 64 | |
| 65 | #include <adns.h> |
| 66 | |
| 67 | #include "alloc.h" |
| 68 | #include "bres.h" |
| 69 | #include "macros.h" |
| 70 | #include "report.h" |
| 71 | #include "sel.h" |
| 72 | |
| 73 | /*----- Static variables --------------------------------------------------*/ |
| 74 | |
| 75 | static adns_state ads; |
| 76 | static sel_state *sel; |
| 77 | static sel_hook selhook; |
| 78 | |
| 79 | /*----- Main code ---------------------------------------------------------*/ |
| 80 | |
| 81 | /* --- @bres_abort@ --- * |
| 82 | * |
| 83 | * Arguments: @bres_client *rc@ = pointer to client block |
| 84 | * |
| 85 | * Returns: --- |
| 86 | * |
| 87 | * Use: Removes a queued job. |
| 88 | */ |
| 89 | |
| 90 | void bres_abort(bres_client *rc) |
| 91 | { |
| 92 | if (rc->q == adns_r_addr) xfree(rc->u.name); |
| 93 | if (rc->a) free(rc->a); |
| 94 | adns_cancel(rc->aq); |
| 95 | } |
| 96 | |
| 97 | /* --- @bres_byaddr@ --- * |
| 98 | * |
| 99 | * Arguments: @bres_client *rc@ = pointer to client block |
| 100 | * @struct in_addr addr@ = address to resolve |
| 101 | * @void (*func)(struct hostent *h, void *p)@ = handler function |
| 102 | * @void *p@ = argument for handler function |
| 103 | * |
| 104 | * Returns: --- |
| 105 | * |
| 106 | * Use: Adds an address lookup job to the queue. The job will be |
| 107 | * processed when there's a spare resolver process to deal with |
| 108 | * it. |
| 109 | */ |
| 110 | |
| 111 | void bres_byaddr(bres_client *rc, struct in_addr addr, |
| 112 | void (*func)(struct hostent */*h*/, void */*p*/), |
| 113 | void *p) |
| 114 | { |
| 115 | int e; |
| 116 | struct sockaddr_in sin; |
| 117 | |
| 118 | if (!ads) goto fail; |
| 119 | sin.sin_family = AF_INET; |
| 120 | sin.sin_addr = addr; |
| 121 | sin.sin_port = 0; |
| 122 | if ((e = adns_submit_reverse(ads, (struct sockaddr *)&sin, adns_r_ptr, |
| 123 | 0, rc, &rc->aq)) != 0) |
| 124 | goto fail; |
| 125 | rc->a = 0; |
| 126 | rc->q = adns_r_ptr; |
| 127 | rc->u.addr = addr; |
| 128 | rc->func = func; |
| 129 | rc->p = p; |
| 130 | return; |
| 131 | |
| 132 | fail: |
| 133 | func(0, p); |
| 134 | } |
| 135 | |
| 136 | /* --- @bres_byname@ --- * |
| 137 | * |
| 138 | * Arguments: @bres_client *rc@ = pointer to client block |
| 139 | * @const char *name@ = name to resolve |
| 140 | * @void (*func)(struct hostent *h, void *p)@ = handler function |
| 141 | * @void *p@ = argument for handler function |
| 142 | * |
| 143 | * Returns: --- |
| 144 | * |
| 145 | * Use: Adds a name lookup job to the queue. The job will be |
| 146 | * processed when there's a spare resolver process to deal with |
| 147 | * it. |
| 148 | */ |
| 149 | |
| 150 | void bres_byname(bres_client *rc, const char *name, |
| 151 | void (*func)(struct hostent */*h*/, void */*p*/), |
| 152 | void *p) |
| 153 | { |
| 154 | int e; |
| 155 | |
| 156 | if (!ads) goto fail; |
| 157 | if ((e = adns_submit(ads, name, adns_r_addr, |
| 158 | adns_qf_search | adns_qf_owner, rc, &rc->aq)) != 0) |
| 159 | goto fail; |
| 160 | rc->a = 0; |
| 161 | rc->q = adns_r_addr; |
| 162 | rc->u.name = xstrdup(name); |
| 163 | rc->func = func; |
| 164 | rc->p = p; |
| 165 | return; |
| 166 | |
| 167 | fail: |
| 168 | func(0, p); |
| 169 | } |
| 170 | |
| 171 | /* --- @bres_exec@ --- * |
| 172 | * |
| 173 | * Arguments: @const char *file@ = file containing server code or null |
| 174 | * |
| 175 | * Returns: --- |
| 176 | * |
| 177 | * Use: Makes `bres' use a standalone server rather than copies of |
| 178 | * the current process. This can reduce memory consumption for |
| 179 | * large processes, at the expense of startup time (which |
| 180 | * shouldn't be too bad anyway, because of the resolver design). |
| 181 | * If the filename is null, a default set up at install time is |
| 182 | * used. It's probably a good idea to leave it alone. |
| 183 | */ |
| 184 | |
| 185 | void bres_exec(const char *file) |
| 186 | { |
| 187 | /* Nothin' doin' */ |
| 188 | } |
| 189 | |
| 190 | /* --- @report@ --- * |
| 191 | * |
| 192 | * Arguments: @bres_client *c@ = client descriptor block |
| 193 | * @adns_answer *a@ = A-record answer from resolver library |
| 194 | * @adns_rr_addr *av@ = vector of address records |
| 195 | * @int an@ = number of address records (must be positive) |
| 196 | * @char **nv@ = vector of name strings |
| 197 | * @int nn@ = number of name strings (must be positive) |
| 198 | * |
| 199 | * Returns: --- |
| 200 | * |
| 201 | * Use: Formats the given answer into a @struct hostent@ and reports |
| 202 | * it to the waiting client application. |
| 203 | */ |
| 204 | |
| 205 | static void report(bres_client *rc, adns_answer *a, |
| 206 | adns_rr_addr *av, int an, |
| 207 | char **nv, int nn) |
| 208 | { |
| 209 | struct hostent h; |
| 210 | char *n[16]; |
| 211 | char *aa[16]; |
| 212 | int i, j; |
| 213 | |
| 214 | j = 0; |
| 215 | if (a->cname) n[j++] = a->cname; |
| 216 | else { n[j++] = *nv; nv++; nn--; } |
| 217 | for (i = 0; i < nn && j < N(n) - 1; i++) |
| 218 | if (strcmp(n[0], nv[i]) != 0) n[j++] = nv[i]; |
| 219 | n[j++] = 0; |
| 220 | for (i = j = 0; i < an && j < N(av) - 1; i++) { |
| 221 | if (av[i].addr.sa.sa_family == AF_INET) |
| 222 | aa[j++] = (char *)&av[i].addr.inet.sin_addr; |
| 223 | } |
| 224 | aa[j++] = 0; |
| 225 | h.h_name = n[0]; |
| 226 | h.h_aliases = n + 1; |
| 227 | h.h_addrtype = AF_INET; |
| 228 | h.h_length = sizeof(struct in_addr); |
| 229 | h.h_addr_list = aa; |
| 230 | rc->func(&h, rc->p); |
| 231 | } |
| 232 | |
| 233 | /* --- @beforehook@, @afterhook@ --- * |
| 234 | * |
| 235 | * Arguments: @sel_state *s@ = select state |
| 236 | * @sel_args *sa@ = argument block |
| 237 | * @void *p@ = uninteresting pointer |
| 238 | * |
| 239 | * Returns: --- |
| 240 | * |
| 241 | * Use: Processes the selector's arguments before @select@ is |
| 242 | * called, to allow ADNS to do its thing. |
| 243 | */ |
| 244 | |
| 245 | static void beforehook(sel_state *s, sel_args *sa, void *p) |
| 246 | { |
| 247 | adns_beforeselect(ads, &sa->maxfd, |
| 248 | &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC], |
| 249 | &sa->tvp, &sa->tv, &sa->now); |
| 250 | } |
| 251 | |
| 252 | static void afterhook(sel_state *s, sel_args *sa, void *p) |
| 253 | { |
| 254 | void *c; |
| 255 | bres_client *rc; |
| 256 | adns_query q; |
| 257 | adns_answer *a, *aa; |
| 258 | int e; |
| 259 | int i; |
| 260 | |
| 261 | adns_afterselect(ads, sa->maxfd, |
| 262 | &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC], |
| 263 | &sa->now); |
| 264 | while (q = 0, (e = adns_check(ads, &q, &a, &c)) == 0) { |
| 265 | rc = c; |
| 266 | if (a->status != 0) |
| 267 | goto fail; |
| 268 | else switch (rc->q) { |
| 269 | case adns_r_addr: |
| 270 | assert(a->type == adns_r_addr); |
| 271 | xfree(rc->u.name); |
| 272 | report(rc, a, a->rrs.addr, a->nrrs, &a->owner, 1); |
| 273 | free(a); |
| 274 | break; |
| 275 | case adns_r_ptr: |
| 276 | if (a->type == adns_r_ptr) { |
| 277 | rc->a = a; |
| 278 | if ((e = adns_submit(ads, a->rrs.str[0], adns_r_addr, |
| 279 | 0, rc, &q)) != 0) |
| 280 | goto fail; |
| 281 | rc->aq = q; |
| 282 | } else { |
| 283 | assert(a->type == adns_r_addr); |
| 284 | for (i = 0; i < a->nrrs; i++) { |
| 285 | if (a->rrs.addr[i].addr.sa.sa_family == AF_INET && |
| 286 | a->rrs.addr[i].addr.inet.sin_addr.s_addr == |
| 287 | rc->u.addr.s_addr) |
| 288 | goto match; |
| 289 | } |
| 290 | goto fail; |
| 291 | match: |
| 292 | aa = rc->a; |
| 293 | report(rc, a, &a->rrs.addr[i], 1, aa->rrs.str, aa->nrrs); |
| 294 | free(aa); |
| 295 | free(a); |
| 296 | } |
| 297 | break; |
| 298 | default: |
| 299 | abort(); |
| 300 | } |
| 301 | continue; |
| 302 | |
| 303 | fail: |
| 304 | if (rc->q == adns_r_addr) xfree(rc->u.name); |
| 305 | if (rc->a) free(rc->a); |
| 306 | rc->func(0, rc->p); |
| 307 | free(a); |
| 308 | } |
| 309 | } |
| 310 | |
| 311 | /* --- @bres_init@ --- * |
| 312 | * |
| 313 | * Arguments: @sel_state *s@ = pointer to select multiplexor |
| 314 | * |
| 315 | * Returns: --- |
| 316 | * |
| 317 | * Use: Initializes the background resolver for use. |
| 318 | */ |
| 319 | |
| 320 | void bres_init(sel_state *s) |
| 321 | { |
| 322 | int e; |
| 323 | |
| 324 | if ((e = adns_init(&ads, adns_if_noautosys, 0)) != 0) { |
| 325 | moan("adns_init failed: resolver won't work"); |
| 326 | return; |
| 327 | } |
| 328 | sel_addhook(s, &selhook, beforehook, afterhook, 0); |
| 329 | sel = s; |
| 330 | } |
| 331 | |
| 332 | /*----- That's all, folks -------------------------------------------------*/ |