| 1 |
/* |
| 2 |
* A rewrite of Darren Reeds original res.c As there is nothing |
| 3 |
* left of Darrens original code, this is now licensed by the hybrid group. |
| 4 |
* (Well, some of the function names are the same, and bits of the structs..) |
| 5 |
* You can use it where it is useful, free even. Buy us a beer and stuff. |
| 6 |
* |
| 7 |
* The authors takes no responsibility for any damage or loss |
| 8 |
* of property which results from the use of this software. |
| 9 |
* |
| 10 |
* $Id$ |
| 11 |
* |
| 12 |
* July 1999 - Rewrote a bunch of stuff here. Change hostent builder code, |
| 13 |
* added callbacks and reference counting of returned hostents. |
| 14 |
* --Bleep (Thomas Helvey <tomh@inxpress.net>) |
| 15 |
* |
| 16 |
* This was all needlessly complicated for irc. Simplified. No more hostent |
| 17 |
* All we really care about is the IP -> hostname mappings. Thats all. |
| 18 |
* |
| 19 |
* Apr 28, 2003 --cryogen and Dianora |
| 20 |
*/ |
| 21 |
|
| 22 |
#include "stdinc.h" |
| 23 |
#include "tools.h" |
| 24 |
#include "client.h" |
| 25 |
#include "list.h" |
| 26 |
#include "common.h" |
| 27 |
#include "event.h" |
| 28 |
#include "irc_string.h" |
| 29 |
#include "sprintf_irc.h" |
| 30 |
#include "ircd.h" |
| 31 |
#include "numeric.h" |
| 32 |
#include "restart.h" |
| 33 |
#include "fdlist.h" |
| 34 |
#include "fileio.h" /* for fbopen / fbclose / fbputs */ |
| 35 |
#include "s_bsd.h" |
| 36 |
#include "s_log.h" |
| 37 |
#include "send.h" |
| 38 |
#include "memory.h" |
| 39 |
#include "irc_res.h" |
| 40 |
#include "irc_reslib.h" |
| 41 |
#include "irc_getnameinfo.h" |
| 42 |
|
| 43 |
#if (CHAR_BIT != 8) |
| 44 |
#error this code needs to be able to address individual octets |
| 45 |
#endif |
| 46 |
|
| 47 |
static PF res_readreply; |
| 48 |
|
| 49 |
#define MAXPACKET 1024 /* rfc sez 512 but we expand names so ... */ |
| 50 |
#define RES_MAXALIASES 35 /* maximum aliases allowed */ |
| 51 |
#define RES_MAXADDRS 35 /* maximum addresses allowed */ |
| 52 |
#define AR_TTL 600 /* TTL in seconds for dns cache entries */ |
| 53 |
|
| 54 |
/* RFC 1104/1105 wasn't very helpful about what these fields |
| 55 |
* should be named, so for now, we'll just name them this way. |
| 56 |
* we probably should look at what named calls them or something. |
| 57 |
*/ |
| 58 |
#define TYPE_SIZE (size_t)2 |
| 59 |
#define CLASS_SIZE (size_t)2 |
| 60 |
#define TTL_SIZE (size_t)4 |
| 61 |
#define RDLENGTH_SIZE (size_t)2 |
| 62 |
#define ANSWER_FIXED_SIZE (TYPE_SIZE + CLASS_SIZE + TTL_SIZE + RDLENGTH_SIZE) |
| 63 |
|
| 64 |
typedef enum |
| 65 |
{ |
| 66 |
REQ_IDLE, /* We're doing not much at all */ |
| 67 |
REQ_PTR, /* Looking up a PTR */ |
| 68 |
REQ_A, /* Looking up an A, possibly because AAAA failed */ |
| 69 |
#ifdef IPV6 |
| 70 |
REQ_AAAA, /* Looking up an AAAA */ |
| 71 |
#endif |
| 72 |
REQ_CNAME, /* We got a CNAME in response, we better get a real answer next */ |
| 73 |
REQ_INT /* ip6.arpa failed, falling back to ip6.int */ |
| 74 |
} request_state; |
| 75 |
|
| 76 |
struct reslist |
| 77 |
{ |
| 78 |
dlink_node node; |
| 79 |
int id; |
| 80 |
int sent; /* number of requests sent */ |
| 81 |
request_state state; /* State the resolver machine is in */ |
| 82 |
time_t ttl; |
| 83 |
char type; |
| 84 |
char retries; /* retry counter */ |
| 85 |
char sends; /* number of sends (>1 means resent) */ |
| 86 |
char resend; /* send flag. 0 == dont resend */ |
| 87 |
time_t sentat; |
| 88 |
time_t timeout; |
| 89 |
struct irc_ssaddr addr; |
| 90 |
char *name; |
| 91 |
struct DNSQuery *query; /* query callback for this request */ |
| 92 |
}; |
| 93 |
|
| 94 |
static fde_t ResolverFileDescriptor; |
| 95 |
static dlink_list request_list = { NULL, NULL, 0 }; |
| 96 |
|
| 97 |
static void rem_request(struct reslist *request); |
| 98 |
static struct reslist *make_request(struct DNSQuery *query); |
| 99 |
static void do_query_name(struct DNSQuery *query, |
| 100 |
const char* name, struct reslist *request, int); |
| 101 |
static void do_query_number(struct DNSQuery *query, |
| 102 |
const struct irc_ssaddr *, |
| 103 |
struct reslist *request); |
| 104 |
static void query_name(const char *name, int query_class, int query_type, |
| 105 |
struct reslist *request); |
| 106 |
static int send_res_msg(const char *buf, int len, int count); |
| 107 |
static void resend_query(struct reslist *request); |
| 108 |
static int proc_answer(struct reslist *request, HEADER *header, char *, char *); |
| 109 |
static struct reslist *find_id(int id); |
| 110 |
static struct DNSReply *make_dnsreply(struct reslist *request); |
| 111 |
|
| 112 |
extern struct irc_ssaddr irc_nsaddr_list[IRCD_MAXNS]; |
| 113 |
extern int irc_nscount; |
| 114 |
extern char irc_domain[HOSTLEN+1]; |
| 115 |
|
| 116 |
|
| 117 |
/* |
| 118 |
* int |
| 119 |
* res_ourserver(inp) |
| 120 |
* looks up "inp" in irc_nsaddr_list[] |
| 121 |
* returns: |
| 122 |
* 0 : not found |
| 123 |
* >0 : found |
| 124 |
* author: |
| 125 |
* paul vixie, 29may94 |
| 126 |
* revised for ircd, cryogen(stu) may03 |
| 127 |
*/ |
| 128 |
static int |
| 129 |
res_ourserver(const struct irc_ssaddr *inp) |
| 130 |
{ |
| 131 |
#ifdef IPV6 |
| 132 |
struct sockaddr_in6 *v6; |
| 133 |
struct sockaddr_in6 *v6in = (struct sockaddr_in6 *)inp; |
| 134 |
#endif |
| 135 |
struct sockaddr_in *v4; |
| 136 |
struct sockaddr_in *v4in = (struct sockaddr_in *)inp; |
| 137 |
int ns; |
| 138 |
|
| 139 |
for (ns = 0; ns < irc_nscount; ns++) |
| 140 |
{ |
| 141 |
const struct irc_ssaddr *srv = &irc_nsaddr_list[ns]; |
| 142 |
#ifdef IPV6 |
| 143 |
v6 = (struct sockaddr_in6 *)srv; |
| 144 |
#endif |
| 145 |
v4 = (struct sockaddr_in *)srv; |
| 146 |
|
| 147 |
/* could probably just memcmp(srv, inp, srv.ss_len) here |
| 148 |
* but we'll air on the side of caution - stu |
| 149 |
* |
| 150 |
*/ |
| 151 |
switch (srv->ss.ss_family) |
| 152 |
{ |
| 153 |
#ifdef IPV6 |
| 154 |
case AF_INET6: |
| 155 |
if (srv->ss.ss_family == inp->ss.ss_family) |
| 156 |
if (v6->sin6_port == v6in->sin6_port) |
| 157 |
if ((memcmp(&v6->sin6_addr.s6_addr, &v6in->sin6_addr.s6_addr, |
| 158 |
sizeof(struct in6_addr)) == 0) || |
| 159 |
(memcmp(&v6->sin6_addr.s6_addr, &in6addr_any, |
| 160 |
sizeof(struct in6_addr)) == 0)) |
| 161 |
return(1); |
| 162 |
break; |
| 163 |
#endif |
| 164 |
case AF_INET: |
| 165 |
if (srv->ss.ss_family == inp->ss.ss_family) |
| 166 |
if (v4->sin_port == v4in->sin_port) |
| 167 |
if ((v4->sin_addr.s_addr == INADDR_ANY) || |
| 168 |
(v4->sin_addr.s_addr == v4in->sin_addr.s_addr)) |
| 169 |
return(1); |
| 170 |
break; |
| 171 |
default: |
| 172 |
break; |
| 173 |
} |
| 174 |
} |
| 175 |
|
| 176 |
return(0); |
| 177 |
} |
| 178 |
|
| 179 |
/* |
| 180 |
* timeout_query_list - Remove queries from the list which have been |
| 181 |
* there too long without being resolved. |
| 182 |
*/ |
| 183 |
static time_t |
| 184 |
timeout_query_list(time_t now) |
| 185 |
{ |
| 186 |
dlink_node *ptr; |
| 187 |
dlink_node *next_ptr; |
| 188 |
struct reslist *request; |
| 189 |
time_t next_time = 0; |
| 190 |
time_t timeout = 0; |
| 191 |
|
| 192 |
DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head) |
| 193 |
{ |
| 194 |
request = ptr->data; |
| 195 |
timeout = request->sentat + request->timeout; |
| 196 |
|
| 197 |
if (now >= timeout) |
| 198 |
{ |
| 199 |
if (--request->retries <= 0) |
| 200 |
{ |
| 201 |
(*request->query->callback)(request->query->ptr, NULL); |
| 202 |
rem_request(request); |
| 203 |
continue; |
| 204 |
} |
| 205 |
else |
| 206 |
{ |
| 207 |
request->sentat = now; |
| 208 |
request->timeout += request->timeout; |
| 209 |
resend_query(request); |
| 210 |
} |
| 211 |
} |
| 212 |
|
| 213 |
if ((next_time == 0) || timeout < next_time) |
| 214 |
{ |
| 215 |
next_time = timeout; |
| 216 |
} |
| 217 |
} |
| 218 |
|
| 219 |
return((next_time > now) ? next_time : (now + AR_TTL)); |
| 220 |
} |
| 221 |
|
| 222 |
/* |
| 223 |
* timeout_resolver - check request list |
| 224 |
*/ |
| 225 |
static void |
| 226 |
timeout_resolver(void *notused) |
| 227 |
{ |
| 228 |
timeout_query_list(CurrentTime); |
| 229 |
} |
| 230 |
|
| 231 |
/* |
| 232 |
* start_resolver - do everything we need to read the resolv.conf file |
| 233 |
* and initialize the resolver file descriptor if needed |
| 234 |
*/ |
| 235 |
static void |
| 236 |
start_resolver(void) |
| 237 |
{ |
| 238 |
irc_res_init(); |
| 239 |
|
| 240 |
if (!ResolverFileDescriptor.flags.open) |
| 241 |
{ |
| 242 |
if (comm_open(&ResolverFileDescriptor, irc_nsaddr_list[0].ss.ss_family, |
| 243 |
SOCK_DGRAM, 0, "Resolver socket") == -1) |
| 244 |
return; |
| 245 |
|
| 246 |
/* At the moment, the resolver FD data is global .. */ |
| 247 |
comm_setselect(&ResolverFileDescriptor, COMM_SELECT_READ, |
| 248 |
res_readreply, NULL, 0); |
| 249 |
eventAdd("timeout_resolver", timeout_resolver, NULL, 1); |
| 250 |
} |
| 251 |
} |
| 252 |
|
| 253 |
/* |
| 254 |
* init_resolver - initialize resolver and resolver library |
| 255 |
*/ |
| 256 |
void |
| 257 |
init_resolver(void) |
| 258 |
{ |
| 259 |
#ifdef HAVE_SRAND48 |
| 260 |
srand48(CurrentTime); |
| 261 |
#endif |
| 262 |
memset(&ResolverFileDescriptor, 0, sizeof(fde_t)); |
| 263 |
start_resolver(); |
| 264 |
} |
| 265 |
|
| 266 |
/* |
| 267 |
* restart_resolver - reread resolv.conf, reopen socket |
| 268 |
*/ |
| 269 |
void |
| 270 |
restart_resolver(void) |
| 271 |
{ |
| 272 |
fd_close(&ResolverFileDescriptor); |
| 273 |
eventDelete(timeout_resolver, NULL); /* -ddosen */ |
| 274 |
start_resolver(); |
| 275 |
} |
| 276 |
|
| 277 |
/* |
| 278 |
* add_local_domain - Add the domain to hostname, if it is missing |
| 279 |
* (as suggested by eps@TOASTER.SFSU.EDU) |
| 280 |
*/ |
| 281 |
void |
| 282 |
add_local_domain(char *hname, size_t size) |
| 283 |
{ |
| 284 |
/* try to fix up unqualified names |
| 285 |
*/ |
| 286 |
if (strchr(hname, '.') == NULL) |
| 287 |
{ |
| 288 |
if (irc_domain[0]) |
| 289 |
{ |
| 290 |
size_t len = strlen(hname); |
| 291 |
|
| 292 |
if ((strlen(irc_domain) + len + 2) < size) |
| 293 |
{ |
| 294 |
hname[len++] = '.'; |
| 295 |
strcpy(hname + len, irc_domain); |
| 296 |
} |
| 297 |
} |
| 298 |
} |
| 299 |
} |
| 300 |
|
| 301 |
/* |
| 302 |
* rem_request - remove a request from the list. |
| 303 |
* This must also free any memory that has been allocated for |
| 304 |
* temporary storage of DNS results. |
| 305 |
*/ |
| 306 |
static void |
| 307 |
rem_request(struct reslist *request) |
| 308 |
{ |
| 309 |
dlinkDelete(&request->node, &request_list); |
| 310 |
MyFree(request->name); |
| 311 |
MyFree(request); |
| 312 |
} |
| 313 |
|
| 314 |
/* |
| 315 |
* make_request - Create a DNS request record for the server. |
| 316 |
*/ |
| 317 |
static struct reslist * |
| 318 |
make_request(struct DNSQuery* query) |
| 319 |
{ |
| 320 |
struct reslist *request; |
| 321 |
|
| 322 |
request = (struct reslist *)MyMalloc(sizeof(struct reslist)); |
| 323 |
memset(request, 0, sizeof(struct reslist)); |
| 324 |
|
| 325 |
request->sentat = CurrentTime; |
| 326 |
request->retries = 3; |
| 327 |
request->resend = 1; |
| 328 |
request->timeout = 4; /* start at 4 and exponential inc. */ |
| 329 |
memset(&request->addr, 0, sizeof(request->addr)); |
| 330 |
request->query = query; |
| 331 |
request->state = REQ_IDLE; |
| 332 |
|
| 333 |
dlinkAdd(request, &request->node, &request_list); |
| 334 |
return(request); |
| 335 |
} |
| 336 |
|
| 337 |
/* |
| 338 |
* delete_resolver_queries - cleanup outstanding queries |
| 339 |
* for which there no longer exist clients or conf lines. |
| 340 |
*/ |
| 341 |
void |
| 342 |
delete_resolver_queries(const struct DNSQuery *query) |
| 343 |
{ |
| 344 |
dlink_node *ptr; |
| 345 |
dlink_node *next_ptr; |
| 346 |
struct reslist *request; |
| 347 |
|
| 348 |
DLINK_FOREACH_SAFE(ptr, next_ptr, request_list.head) |
| 349 |
{ |
| 350 |
if ((request = ptr->data) != NULL) |
| 351 |
{ |
| 352 |
if (query == request->query) |
| 353 |
rem_request(request); |
| 354 |
} |
| 355 |
} |
| 356 |
} |
| 357 |
|
| 358 |
/* |
| 359 |
* send_res_msg - sends msg to all nameservers found in the "_res" structure. |
| 360 |
* This should reflect /etc/resolv.conf. We will get responses |
| 361 |
* which arent needed but is easier than checking to see if nameserver |
| 362 |
* isnt present. Returns number of messages successfully sent to |
| 363 |
* nameservers or -1 if no successful sends. |
| 364 |
*/ |
| 365 |
static int |
| 366 |
send_res_msg(const char *msg, int len, int rcount) |
| 367 |
{ |
| 368 |
int i; |
| 369 |
int sent = 0; |
| 370 |
int max_queries = IRCD_MIN(irc_nscount, rcount); |
| 371 |
|
| 372 |
/* RES_PRIMARY option is not implemented |
| 373 |
* if (res.options & RES_PRIMARY || 0 == max_queries) |
| 374 |
*/ |
| 375 |
if (max_queries == 0) |
| 376 |
max_queries = 1; |
| 377 |
|
| 378 |
for (i = 0; i < max_queries; i++) |
| 379 |
{ |
| 380 |
if (sendto(ResolverFileDescriptor.fd, msg, len, 0, |
| 381 |
(struct sockaddr*)&(irc_nsaddr_list[i]), |
| 382 |
irc_nsaddr_list[i].ss_len) == len) |
| 383 |
++sent; |
| 384 |
} |
| 385 |
|
| 386 |
return(sent); |
| 387 |
} |
| 388 |
|
| 389 |
/* |
| 390 |
* find_id - find a dns request id (id is determined by dn_mkquery) |
| 391 |
*/ |
| 392 |
static struct reslist * |
| 393 |
find_id(int id) |
| 394 |
{ |
| 395 |
dlink_node *ptr; |
| 396 |
struct reslist *request; |
| 397 |
|
| 398 |
DLINK_FOREACH(ptr, request_list.head) |
| 399 |
{ |
| 400 |
request = ptr->data; |
| 401 |
|
| 402 |
if (request->id == id) |
| 403 |
return(request); |
| 404 |
} |
| 405 |
|
| 406 |
return(NULL); |
| 407 |
} |
| 408 |
|
| 409 |
/* |
| 410 |
* gethost_byname_type - get host address from name |
| 411 |
* |
| 412 |
*/ |
| 413 |
void |
| 414 |
gethost_byname_type(const char *name, struct DNSQuery *query, int type) |
| 415 |
{ |
| 416 |
assert(name != 0); |
| 417 |
do_query_name(query, name, NULL, type); |
| 418 |
} |
| 419 |
|
| 420 |
/* |
| 421 |
* gethost_byname - wrapper for _type - send T_AAAA first if IPV6 supported |
| 422 |
*/ |
| 423 |
void |
| 424 |
gethost_byname(const char *name, struct DNSQuery *query) |
| 425 |
{ |
| 426 |
#ifdef IPV6 |
| 427 |
gethost_byname_type(name, query, T_AAAA); |
| 428 |
#else |
| 429 |
gethost_byname_type(name, query, T_A); |
| 430 |
#endif |
| 431 |
} |
| 432 |
|
| 433 |
/* |
| 434 |
* gethost_byaddr - get host name from address |
| 435 |
*/ |
| 436 |
void |
| 437 |
gethost_byaddr(const struct irc_ssaddr *addr, struct DNSQuery *query) |
| 438 |
{ |
| 439 |
do_query_number(query, addr, NULL); |
| 440 |
} |
| 441 |
|
| 442 |
/* |
| 443 |
* do_query_name - nameserver lookup name |
| 444 |
*/ |
| 445 |
static void |
| 446 |
do_query_name(struct DNSQuery *query, const char *name, |
| 447 |
struct reslist *request, int type) |
| 448 |
{ |
| 449 |
char host_name[HOSTLEN + 1]; |
| 450 |
|
| 451 |
strlcpy(host_name, name, HOSTLEN); |
| 452 |
add_local_domain(host_name, HOSTLEN); |
| 453 |
|
| 454 |
if (request == NULL) |
| 455 |
{ |
| 456 |
request = make_request(query); |
| 457 |
request->name = (char *)MyMalloc(strlen(host_name) + 1); |
| 458 |
request->type = type; |
| 459 |
strcpy(request->name, host_name); |
| 460 |
#ifdef IPV6 |
| 461 |
if (type == T_A) |
| 462 |
request->state = REQ_A; |
| 463 |
else |
| 464 |
request->state = REQ_AAAA; |
| 465 |
#else |
| 466 |
request->state = REQ_A; |
| 467 |
#endif |
| 468 |
} |
| 469 |
|
| 470 |
request->type = type; |
| 471 |
query_name(host_name, C_IN, type, request); |
| 472 |
} |
| 473 |
|
| 474 |
/* |
| 475 |
* do_query_number - Use this to do reverse IP# lookups. |
| 476 |
*/ |
| 477 |
static void |
| 478 |
do_query_number(struct DNSQuery *query, const struct irc_ssaddr *addr, |
| 479 |
struct reslist *request) |
| 480 |
{ |
| 481 |
char ipbuf[128]; |
| 482 |
const unsigned char *cp; |
| 483 |
#ifdef IPV6 |
| 484 |
const char *intarpa; |
| 485 |
#endif |
| 486 |
if (addr->ss.ss_family == AF_INET) |
| 487 |
{ |
| 488 |
struct sockaddr_in *v4 = (struct sockaddr_in *)addr; |
| 489 |
cp = (const unsigned char*)&v4->sin_addr.s_addr; |
| 490 |
|
| 491 |
ircsprintf(ipbuf, "%u.%u.%u.%u.in-addr.arpa.", |
| 492 |
(unsigned int)(cp[3]), (unsigned int)(cp[2]), |
| 493 |
(unsigned int)(cp[1]), (unsigned int)(cp[0])); |
| 494 |
} |
| 495 |
#ifdef IPV6 |
| 496 |
else if (addr->ss.ss_family == AF_INET6) |
| 497 |
{ |
| 498 |
struct sockaddr_in6 *v6 = (struct sockaddr_in6 *)addr; |
| 499 |
cp = (const unsigned char *)&v6->sin6_addr.s6_addr; |
| 500 |
|
| 501 |
if (request != NULL && request->state == REQ_INT) |
| 502 |
intarpa = "int"; |
| 503 |
else |
| 504 |
intarpa = "arpa"; |
| 505 |
|
| 506 |
(void)sprintf(ipbuf, "%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x." |
| 507 |
"%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.%x.ip6.%s.", |
| 508 |
(unsigned int)(cp[15]&0xf), (unsigned int)(cp[15]>>4), |
| 509 |
(unsigned int)(cp[14]&0xf), (unsigned int)(cp[14]>>4), |
| 510 |
(unsigned int)(cp[13]&0xf), (unsigned int)(cp[13]>>4), |
| 511 |
(unsigned int)(cp[12]&0xf), (unsigned int)(cp[12]>>4), |
| 512 |
(unsigned int)(cp[11]&0xf), (unsigned int)(cp[11]>>4), |
| 513 |
(unsigned int)(cp[10]&0xf), (unsigned int)(cp[10]>>4), |
| 514 |
(unsigned int)(cp[9]&0xf), (unsigned int)(cp[9]>>4), |
| 515 |
(unsigned int)(cp[8]&0xf), (unsigned int)(cp[8]>>4), |
| 516 |
(unsigned int)(cp[7]&0xf), (unsigned int)(cp[7]>>4), |
| 517 |
(unsigned int)(cp[6]&0xf), (unsigned int)(cp[6]>>4), |
| 518 |
(unsigned int)(cp[5]&0xf), (unsigned int)(cp[5]>>4), |
| 519 |
(unsigned int)(cp[4]&0xf), (unsigned int)(cp[4]>>4), |
| 520 |
(unsigned int)(cp[3]&0xf), (unsigned int)(cp[3]>>4), |
| 521 |
(unsigned int)(cp[2]&0xf), (unsigned int)(cp[2]>>4), |
| 522 |
(unsigned int)(cp[1]&0xf), (unsigned int)(cp[1]>>4), |
| 523 |
(unsigned int)(cp[0]&0xf), (unsigned int)(cp[0]>>4), intarpa); |
| 524 |
} |
| 525 |
#endif |
| 526 |
if (request == NULL) |
| 527 |
{ |
| 528 |
request = make_request(query); |
| 529 |
request->type = T_PTR; |
| 530 |
memcpy(&request->addr, addr, sizeof(struct irc_ssaddr)); |
| 531 |
request->name = (char *)MyMalloc(HOSTLEN + 1); |
| 532 |
} |
| 533 |
|
| 534 |
query_name(ipbuf, C_IN, T_PTR, request); |
| 535 |
} |
| 536 |
|
| 537 |
/* |
| 538 |
* query_name - generate a query based on class, type and name. |
| 539 |
*/ |
| 540 |
static void |
| 541 |
query_name(const char *name, int query_class, int type, |
| 542 |
struct reslist *request) |
| 543 |
{ |
| 544 |
char buf[MAXPACKET]; |
| 545 |
int request_len = 0; |
| 546 |
|
| 547 |
memset(buf, 0, sizeof(buf)); |
| 548 |
|
| 549 |
if ((request_len = irc_res_mkquery(name, query_class, type, |
| 550 |
(unsigned char *)buf, sizeof(buf))) > 0) |
| 551 |
{ |
| 552 |
HEADER *header = (HEADER *)buf; |
| 553 |
#ifndef HAVE_LRAND48 |
| 554 |
int k = 0; |
| 555 |
struct timeval tv; |
| 556 |
#endif |
| 557 |
/* |
| 558 |
* generate an unique id |
| 559 |
* NOTE: we don't have to worry about converting this to and from |
| 560 |
* network byte order, the nameserver does not interpret this value |
| 561 |
* and returns it unchanged |
| 562 |
*/ |
| 563 |
#ifdef HAVE_LRAND48 |
| 564 |
do |
| 565 |
{ |
| 566 |
header->id = (header->id + lrand48()) & 0xffff; |
| 567 |
} while (find_id(header->id)); |
| 568 |
#else |
| 569 |
gettimeofday(&tv, NULL); |
| 570 |
do |
| 571 |
{ |
| 572 |
header->id = (header->id + k + tv.tv_usec) & 0xffff; |
| 573 |
k++; |
| 574 |
} while (find_id(header->id)); |
| 575 |
#endif /* HAVE_LRAND48 */ |
| 576 |
request->id = header->id; |
| 577 |
++request->sends; |
| 578 |
|
| 579 |
request->sent += send_res_msg(buf, request_len, request->sends); |
| 580 |
} |
| 581 |
} |
| 582 |
|
| 583 |
static void |
| 584 |
resend_query(struct reslist *request) |
| 585 |
{ |
| 586 |
if (request->resend == 0) |
| 587 |
return; |
| 588 |
|
| 589 |
switch(request->type) |
| 590 |
{ |
| 591 |
case T_PTR: |
| 592 |
do_query_number(NULL, &request->addr, request); |
| 593 |
break; |
| 594 |
case T_A: |
| 595 |
do_query_name(NULL, request->name, request, request->type); |
| 596 |
break; |
| 597 |
#ifdef IPV6 |
| 598 |
case T_AAAA: |
| 599 |
/* didnt work, try A */ |
| 600 |
if (request->state == REQ_AAAA) |
| 601 |
do_query_name(NULL, request->name, request, T_A); |
| 602 |
#endif |
| 603 |
default: |
| 604 |
break; |
| 605 |
} |
| 606 |
} |
| 607 |
|
| 608 |
/* |
| 609 |
* proc_answer - process name server reply |
| 610 |
*/ |
| 611 |
static int |
| 612 |
proc_answer(struct reslist *request, HEADER* header, char* buf, char* eob) |
| 613 |
{ |
| 614 |
char hostbuf[HOSTLEN + 100]; /* working buffer */ |
| 615 |
unsigned char *current; /* current position in buf */ |
| 616 |
int query_class; /* answer class */ |
| 617 |
int type; /* answer type */ |
| 618 |
int n; /* temp count */ |
| 619 |
int rd_length; |
| 620 |
struct sockaddr_in *v4; /* conversion */ |
| 621 |
#ifdef IPV6 |
| 622 |
struct sockaddr_in6 *v6; |
| 623 |
#endif |
| 624 |
current = (unsigned char *)buf + sizeof(HEADER); |
| 625 |
|
| 626 |
for (; header->qdcount > 0; --header->qdcount) |
| 627 |
{ |
| 628 |
if ((n = irc_dn_skipname(current, (unsigned char *)eob)) < 0) |
| 629 |
break; |
| 630 |
|
| 631 |
current += (size_t) n + QFIXEDSZ; |
| 632 |
} |
| 633 |
|
| 634 |
/* |
| 635 |
* process each answer sent to us blech. |
| 636 |
*/ |
| 637 |
while (header->ancount > 0 && (char *)current < eob) |
| 638 |
{ |
| 639 |
header->ancount--; |
| 640 |
|
| 641 |
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, current, |
| 642 |
hostbuf, sizeof(hostbuf)); |
| 643 |
|
| 644 |
if (n < 0) |
| 645 |
{ |
| 646 |
/* |
| 647 |
* broken message |
| 648 |
*/ |
| 649 |
return(0); |
| 650 |
} |
| 651 |
else if (n == 0) |
| 652 |
{ |
| 653 |
/* |
| 654 |
* no more answers left |
| 655 |
*/ |
| 656 |
return(0); |
| 657 |
} |
| 658 |
|
| 659 |
hostbuf[HOSTLEN] = '\0'; |
| 660 |
|
| 661 |
/* With Address arithmetic you have to be very anal |
| 662 |
* this code was not working on alpha due to that |
| 663 |
* (spotted by rodder/jailbird/dianora) |
| 664 |
*/ |
| 665 |
current += (size_t) n; |
| 666 |
|
| 667 |
if (!(((char *)current + ANSWER_FIXED_SIZE) < eob)) |
| 668 |
break; |
| 669 |
|
| 670 |
type = irc_ns_get16(current); |
| 671 |
current += TYPE_SIZE; |
| 672 |
|
| 673 |
query_class = irc_ns_get16(current); |
| 674 |
current += CLASS_SIZE; |
| 675 |
|
| 676 |
request->ttl = irc_ns_get32(current); |
| 677 |
current += TTL_SIZE; |
| 678 |
|
| 679 |
rd_length = irc_ns_get16(current); |
| 680 |
current += RDLENGTH_SIZE; |
| 681 |
|
| 682 |
/* |
| 683 |
* Wait to set request->type until we verify this structure |
| 684 |
*/ |
| 685 |
switch (type) |
| 686 |
{ |
| 687 |
case T_A: |
| 688 |
if (request->type != T_A) |
| 689 |
return(0); |
| 690 |
|
| 691 |
/* |
| 692 |
* check for invalid rd_length or too many addresses |
| 693 |
*/ |
| 694 |
if (rd_length != sizeof(struct in_addr)) |
| 695 |
return(0); |
| 696 |
v4 = (struct sockaddr_in *)&request->addr; |
| 697 |
request->addr.ss_len = sizeof(struct sockaddr_in); |
| 698 |
v4->sin_family = AF_INET; |
| 699 |
memcpy(&v4->sin_addr, current, sizeof(struct in_addr)); |
| 700 |
return(1); |
| 701 |
break; |
| 702 |
#ifdef IPV6 |
| 703 |
case T_AAAA: |
| 704 |
if (request->type != T_AAAA) |
| 705 |
return(0); |
| 706 |
if (rd_length != sizeof(struct in6_addr)) |
| 707 |
return(0); |
| 708 |
request->addr.ss_len = sizeof(struct sockaddr_in6); |
| 709 |
v6 = (struct sockaddr_in6 *)&request->addr; |
| 710 |
v6->sin6_family = AF_INET6; |
| 711 |
memcpy(&v6->sin6_addr, current, sizeof(struct in6_addr)); |
| 712 |
return(1); |
| 713 |
break; |
| 714 |
#endif |
| 715 |
case T_PTR: |
| 716 |
if (request->type != T_PTR) |
| 717 |
return(0); |
| 718 |
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, |
| 719 |
current, hostbuf, sizeof(hostbuf)); |
| 720 |
if (n < 0) |
| 721 |
return(0); /* broken message */ |
| 722 |
else if (n == 0) |
| 723 |
return(0); /* no more answers left */ |
| 724 |
|
| 725 |
strlcpy(request->name, hostbuf, HOSTLEN); |
| 726 |
|
| 727 |
return(1); |
| 728 |
break; |
| 729 |
case T_CNAME: /* first check we already havent started looking |
| 730 |
into a cname */ |
| 731 |
if (request->type != T_PTR) |
| 732 |
return(0); |
| 733 |
|
| 734 |
if (request->state == REQ_CNAME) |
| 735 |
{ |
| 736 |
n = irc_dn_expand((unsigned char *)buf, (unsigned char *)eob, |
| 737 |
current, hostbuf, sizeof(hostbuf)); |
| 738 |
|
| 739 |
if (n < 0) |
| 740 |
return(0); |
| 741 |
return(1); |
| 742 |
} |
| 743 |
|
| 744 |
request->state = REQ_CNAME; |
| 745 |
current += rd_length; |
| 746 |
break; |
| 747 |
|
| 748 |
default: |
| 749 |
/* XXX I'd rather just throw away the entire bogus thing |
| 750 |
* but its possible its just a broken nameserver with still |
| 751 |
* valid answers. But lets do some rudimentary logging for now... |
| 752 |
*/ |
| 753 |
ilog(L_ERROR, "irc_res.c bogus type %d", type); |
| 754 |
break; |
| 755 |
} |
| 756 |
} |
| 757 |
|
| 758 |
return(1); |
| 759 |
} |
| 760 |
|
| 761 |
/* |
| 762 |
* res_readreply - read a dns reply from the nameserver and process it. |
| 763 |
*/ |
| 764 |
static void |
| 765 |
res_readreply(fde_t *fd, void *data) |
| 766 |
{ |
| 767 |
char buf[sizeof(HEADER) + MAXPACKET]; |
| 768 |
HEADER *header; |
| 769 |
struct reslist *request = NULL; |
| 770 |
struct DNSReply *reply = NULL; |
| 771 |
int rc; |
| 772 |
int answer_count; |
| 773 |
socklen_t len = sizeof(struct irc_ssaddr); |
| 774 |
struct irc_ssaddr lsin; |
| 775 |
|
| 776 |
rc = recvfrom(fd->fd, buf, sizeof(buf), 0, (struct sockaddr *)&lsin, &len); |
| 777 |
|
| 778 |
/* Re-schedule a read *after* recvfrom, or we'll be registering |
| 779 |
* interest where it'll instantly be ready for read :-) -- adrian |
| 780 |
*/ |
| 781 |
comm_setselect(fd, COMM_SELECT_READ, res_readreply, NULL, 0); |
| 782 |
/* Better to cast the sizeof instead of rc */ |
| 783 |
if (rc <= (int)(sizeof(HEADER))) |
| 784 |
return; |
| 785 |
|
| 786 |
/* |
| 787 |
* convert DNS reply reader from Network byte order to CPU byte order. |
| 788 |
*/ |
| 789 |
header = (HEADER *)buf; |
| 790 |
header->ancount = ntohs(header->ancount); |
| 791 |
header->qdcount = ntohs(header->qdcount); |
| 792 |
header->nscount = ntohs(header->nscount); |
| 793 |
header->arcount = ntohs(header->arcount); |
| 794 |
|
| 795 |
/* |
| 796 |
* response for an id which we have already received an answer for |
| 797 |
* just ignore this response. |
| 798 |
*/ |
| 799 |
if (0 == (request = find_id(header->id))) |
| 800 |
return; |
| 801 |
|
| 802 |
/* |
| 803 |
* check against possibly fake replies |
| 804 |
*/ |
| 805 |
if (!res_ourserver(&lsin)) |
| 806 |
return; |
| 807 |
|
| 808 |
if ((header->rcode != NO_ERRORS) || (header->ancount == 0)) |
| 809 |
{ |
| 810 |
if (SERVFAIL == header->rcode) |
| 811 |
resend_query(request); |
| 812 |
else |
| 813 |
{ |
| 814 |
/* |
| 815 |
* If we havent already tried this, and we're looking up AAAA, try A |
| 816 |
* now |
| 817 |
*/ |
| 818 |
|
| 819 |
#ifdef IPV6 |
| 820 |
if (request->state == REQ_AAAA && request->type == T_AAAA) |
| 821 |
{ |
| 822 |
request->timeout += 4; |
| 823 |
resend_query(request); |
| 824 |
} |
| 825 |
else if (request->type == T_PTR && request->state != REQ_INT && |
| 826 |
request->addr.ss.ss_family == AF_INET6) |
| 827 |
{ |
| 828 |
request->state = REQ_INT; |
| 829 |
request->timeout += 4; |
| 830 |
request->retries--; |
| 831 |
resend_query(request); |
| 832 |
} |
| 833 |
else |
| 834 |
#endif |
| 835 |
{ |
| 836 |
/* |
| 837 |
* If a bad error was returned, we stop here and dont send |
| 838 |
* send any more (no retries granted). |
| 839 |
*/ |
| 840 |
(*request->query->callback)(request->query->ptr, NULL); |
| 841 |
rem_request(request); |
| 842 |
} |
| 843 |
} |
| 844 |
|
| 845 |
return; |
| 846 |
} |
| 847 |
/* |
| 848 |
* If this fails there was an error decoding the received packet, |
| 849 |
* try it again and hope it works the next time. |
| 850 |
*/ |
| 851 |
answer_count = proc_answer(request, header, buf, buf + rc); |
| 852 |
|
| 853 |
if (answer_count) |
| 854 |
{ |
| 855 |
if (request->type == T_PTR) |
| 856 |
{ |
| 857 |
if (request->name == NULL) |
| 858 |
{ |
| 859 |
/* |
| 860 |
* got a PTR response with no name, something bogus is happening |
| 861 |
* don't bother trying again, the client address doesn't resolve |
| 862 |
*/ |
| 863 |
(*request->query->callback)(request->query->ptr, reply); |
| 864 |
rem_request(request); |
| 865 |
return; |
| 866 |
} |
| 867 |
|
| 868 |
/* |
| 869 |
* Lookup the 'authoritative' name that we were given for the |
| 870 |
* ip#. |
| 871 |
* |
| 872 |
*/ |
| 873 |
#ifdef IPV6 |
| 874 |
if (request->addr.ss.ss_family == AF_INET6) |
| 875 |
gethost_byname_type(request->name, request->query, T_AAAA); |
| 876 |
else |
| 877 |
#endif |
| 878 |
gethost_byname_type(request->name, request->query, T_A); |
| 879 |
rem_request(request); |
| 880 |
} |
| 881 |
else |
| 882 |
{ |
| 883 |
/* |
| 884 |
* got a name and address response, client resolved |
| 885 |
*/ |
| 886 |
reply = make_dnsreply(request); |
| 887 |
(*request->query->callback)(request->query->ptr, reply); |
| 888 |
MyFree(reply); |
| 889 |
rem_request(request); |
| 890 |
} |
| 891 |
} |
| 892 |
else if (!request->sent) |
| 893 |
{ |
| 894 |
/* XXX - we got a response for a query we didn't send with a valid id? |
| 895 |
* this should never happen, bail here and leave the client unresolved |
| 896 |
*/ |
| 897 |
assert(0); |
| 898 |
|
| 899 |
/* XXX don't leak it */ |
| 900 |
rem_request(request); |
| 901 |
} |
| 902 |
} |
| 903 |
|
| 904 |
static struct DNSReply * |
| 905 |
make_dnsreply(struct reslist *request) |
| 906 |
{ |
| 907 |
struct DNSReply *cp; |
| 908 |
assert(request != 0); |
| 909 |
|
| 910 |
cp = (struct DNSReply *)MyMalloc(sizeof(struct DNSReply)); |
| 911 |
|
| 912 |
cp->h_name = request->name; |
| 913 |
memcpy(&cp->addr, &request->addr, sizeof(cp->addr)); |
| 914 |
return(cp); |
| 915 |
} |
| 916 |
|
| 917 |
void |
| 918 |
report_dns_servers(struct Client *source_p) |
| 919 |
{ |
| 920 |
int i; |
| 921 |
char ipaddr[HOSTIPLEN]; |
| 922 |
|
| 923 |
for (i = 0; i < irc_nscount; i++) |
| 924 |
{ |
| 925 |
irc_getnameinfo((struct sockaddr *)&(irc_nsaddr_list[i]), |
| 926 |
irc_nsaddr_list[i].ss_len, ipaddr, HOSTIPLEN, NULL, 0, |
| 927 |
NI_NUMERICHOST); |
| 928 |
sendto_one(source_p, form_str(RPL_STATSALINE), |
| 929 |
me.name, source_p->name, ipaddr); |
| 930 |
} |
| 931 |
} |