Annotation of libwww/Library/src/HTDNS.c, revision 2.32.2.5
2.1 frystyk 1: /* HTDNS.c
2: ** DOMAIN NAME SERVICE MANAGER
3: **
2.32.2.1 duerst 4: ** (c) COPYRIGHT MIT 1995-2003.
2.1 frystyk 5: ** Please first read the full copyright statement in the file COPYRIGH.
2.32.2.5! duerst 6: ** @(#) $Id: HTDNS.c,v 2.32.2.4 2003/04/02 15:56:21 duerst Exp $
2.1 frystyk 7: **
8: ** This object manages a cache of hosts we have looked up vis DNS.
9: ** The object contains the necessary parts from hostent. For Internet host
10: ** hostent->h_addr_list is not an array of char pointers but an array of
11: ** pointers of type in_addr.
12: **
13: ** 13 Sep 95 HFN Spawned from HTTCP.c and rewritten
2.32.2.1 duerst 14: ** 23 Feb 03 MJD Started working on IDN implementation
2.1 frystyk 15: */
16:
17: /* Library include files */
2.26 frystyk 18: #include "wwwsys.h"
2.21 frystyk 19: #include "WWWUtil.h"
2.1 frystyk 20: #include "HTParse.h"
21: #include "HTAlert.h"
22: #include "HTError.h"
2.21 frystyk 23: #include "HTTrans.h"
2.23 frystyk 24: #include "HTHstMan.h"
2.1 frystyk 25: #include "HTDNS.h" /* Implemented here */
26:
2.32.2.2 duerst 27: #include "idn/api.h"
28:
2.25 frystyk 29: #define DNS_TIMEOUT 1800L /* Default DNS timeout is 30 mn */
2.1 frystyk 30:
31: /* Type definitions and global variables etc. local to this module */
32: struct _HTdns {
2.21 frystyk 33: char * hostname; /* name of host */
2.1 frystyk 34: time_t ntime; /* Creation time */
35: int addrlength; /* Length of address in bytes */
36: int homes; /* Number of IP addresses on the host */
37: char ** addrlist; /* List of addresses from name server */
38: double * weight; /* Weight on each address */
39: };
40:
2.2 frystyk 41: PRIVATE HTList **CacheTable = NULL;
42: PRIVATE time_t DNSTimeout = DNS_TIMEOUT; /* Timeout on DNS entries */
2.1 frystyk 43:
44: /* ------------------------------------------------------------------------- */
45:
2.20 frystyk 46: PRIVATE void free_object (HTdns * me)
2.1 frystyk 47: {
48: if (me) {
2.17 frystyk 49: HT_FREE(me->hostname);
2.1 frystyk 50: if (*me->addrlist)
2.17 frystyk 51: HT_FREE(*me->addrlist);
52: HT_FREE(me->addrlist);
53: HT_FREE(me->weight);
54: HT_FREE(me);
2.1 frystyk 55: }
56: }
57:
2.21 frystyk 58: PRIVATE BOOL delete_object (HTList * list, HTdns * me)
2.1 frystyk 59: {
2.30 frystyk 60: HTTRACE(PROT_TRACE, "DNS Delete.. object %p from list %p\n" _ me _ list);
2.1 frystyk 61: HTList_removeObject(list, (void *) me);
2.20 frystyk 62: free_object(me);
2.1 frystyk 63: return YES;
64: }
65:
66: /* HTDNS_setTimeout
67: ** ----------------
68: ** Set the cache timeout for DNS entries. Default is DNS_TIMEOUT
69: */
70: PUBLIC void HTDNS_setTimeout (time_t timeout)
71: {
72: DNSTimeout = timeout;
73: }
74:
75: /* HTDNS_timeout
76: ** -------------
77: ** Get the cache timeout
78: */
79: PUBLIC time_t HTDNS_timeout (time_t timeout)
80: {
81: return DNSTimeout;
82: }
83:
84: /* HTDNS_add
85: ** ---------
86: ** Add an element to the cache of visited hosts. Note that this function
87: ** requires the system implemented structure hostent and not our own
2.21 frystyk 88: ** host_info. The homes variable indicates the number of IP addresses
89: ** found. A host name must NOT contain a port number.
90: ** Returns address of new HTdns object
2.1 frystyk 91: */
2.22 frystyk 92: PUBLIC HTdns * HTDNS_add (HTList * list, struct hostent * element,
93: char *host, int *homes)
2.1 frystyk 94: {
95: HTdns *me;
2.21 frystyk 96: char *addr = NULL;
2.1 frystyk 97: char **index = element->h_addr_list;
98: int cnt = 1;
99:
100: while(*index++) cnt++;
2.17 frystyk 101: if ((me = (HTdns *) HT_CALLOC(1, sizeof(HTdns))) == NULL ||
102: (me->addrlist = (char **) HT_CALLOC(1, cnt*sizeof(char*))) == NULL ||
103: (addr = (char *) HT_CALLOC(1, cnt*element->h_length)) == NULL)
104: HT_OUTOFMEM("HTDNS_add");
2.1 frystyk 105: StrAllocCopy(me->hostname, host);
106: me->ntime = time(NULL);
107: index = element->h_addr_list;
108: cnt = 0;
109: while (*index) {
110: *(me->addrlist+cnt) = addr+cnt*element->h_length;
111: memcpy((void *) *(me->addrlist+cnt++), *index++, element->h_length);
112: }
113: me->homes = cnt;
114: *homes = cnt;
2.17 frystyk 115: if ((me->weight = (double *) HT_CALLOC(me->homes, sizeof(double))) == NULL)
116: HT_OUTOFMEM("HTDNS_add");
2.1 frystyk 117: me->addrlength = element->h_length;
2.30 frystyk 118: HTTRACE(PROT_TRACE, "DNS Add..... `%s\' with %d home(s) to %p\n" _
119: host _ *homes _ list);
2.1 frystyk 120: HTList_addObject(list, (void *) me);
121: return me;
122: }
123:
124:
125: /* HTDNS_updateWeights
126: ** -------------------
127: ** This function calculates the weights of the different IP addresses
128: ** on a multi homed host. Each weight is calculated as
129: **
130: ** w(n+1) = w(n)*a + (1-a) * deltatime
131: ** a = exp(-1/Neff)
132: ** Neff is the effective number of samples used
133: ** deltatime is time spend on making a connection
134: **
135: ** A short window (low Neff) gives a high sensibility, but this is
136: ** required as we can't expect a lot of data to test on.
2.21 frystyk 137: ** "current" is the index returned by HTGetHostByName()
2.1 frystyk 138: */
2.24 frystyk 139: PUBLIC BOOL HTDNS_updateWeigths(HTdns *dns, int current, ms_t deltatime)
2.1 frystyk 140: {
141: if (dns) {
142: int cnt;
2.19 frystyk 143: const double passive = 0.9; /* Factor for all passive IP_addrs */
2.1 frystyk 144: #if 0
2.19 frystyk 145: const int Neff = 3;
146: const double alpha = exp(-1.0/Neff);
2.1 frystyk 147: #else
2.19 frystyk 148: const double alpha = 0.716531310574; /* Doesn't need the math lib */
2.1 frystyk 149: #endif
150: for (cnt=0; cnt<dns->homes; cnt++) {
151: if (cnt == current) {
152: *(dns->weight+current) = *(dns->weight+current)*alpha + (1.0-alpha)*deltatime;
2.16 frystyk 153: if (*(dns->weight+current) < 0.0) *(dns->weight+current) = 0.0;
2.1 frystyk 154: } else {
155: *(dns->weight+cnt) = *(dns->weight+cnt) * passive;
156: }
2.30 frystyk 157: HTTRACE(PROT_TRACE, "DNS weight.. Home %d has weight %4.2f\n" _ cnt _
2.1 frystyk 158: *(dns->weight+cnt));
159: }
160: return YES;
161: }
2.30 frystyk 162: HTTRACE(PROT_TRACE, "DNS weight.. Object %p not found'\n" _ dns);
2.1 frystyk 163: return NO;
164: }
165:
166: /* HTDNS_delete
167: ** ------------
168: ** Remove an element from the cache
169: */
2.19 frystyk 170: PUBLIC BOOL HTDNS_delete (const char * host)
2.1 frystyk 171: {
172: HTList *list;
173: int hash = 0;
2.19 frystyk 174: const char *ptr;
2.1 frystyk 175: if (!host || !CacheTable) return NO;
176: for(ptr=host; *ptr; ptr++)
2.29 frystyk 177: hash = (int) ((hash * 3 + (*(unsigned char *) ptr)) % HT_M_HASH_SIZE);
2.1 frystyk 178: if ((list = CacheTable[hash])) { /* We have the list, find the entry */
179: HTdns *pres;
180: while ((pres = (HTdns *) HTList_nextObject(list))) {
181: if (!strcmp(pres->hostname, host)) {
182: delete_object(CacheTable[hash], pres);
183: break;
184: }
185: }
186: }
187: return YES;
188: }
189:
190: /* HTDNS_deleteAll
191: ** ---------------
192: ** Destroys the cache completely
193: */
194: PUBLIC BOOL HTDNS_deleteAll (void)
195: {
196: int cnt;
197: HTList *cur;
198: if (!CacheTable) return NO;
2.29 frystyk 199: for (cnt=0; cnt<HT_M_HASH_SIZE; cnt++) {
2.1 frystyk 200: if ((cur = CacheTable[cnt])) {
201: HTdns *pres;
202: while ((pres = (HTdns *) HTList_nextObject(cur)) != NULL)
2.20 frystyk 203: free_object(pres);
2.1 frystyk 204: }
205: HTList_delete(CacheTable[cnt]);
206: CacheTable[cnt] = NULL;
2.2 frystyk 207: }
2.21 frystyk 208: HT_FREE(CacheTable);
2.2 frystyk 209: return YES;
210: }
2.1 frystyk 211:
2.32.2.1 duerst 212: /* Decode one hex character
213: */
214: /* copied from HTSRC.c, where it is not used */
215: PRIVATE long from_hex (char c)
216: {
217: return (c>='0')&&(c<='9') ? c-'0'
218: : (c>='A')&&(c<='F') ? c-'A'+10
219: : (c>='a')&&(c<='f') ? c-'a'+10
220: : 0;
221: }
222:
2.32.2.4 duerst 223: /* HTACEfromUTF8
224: ** -------------
225: ** Convert Internationalized Domain Name in UTF-8 to Ascii Compatible
2.32.2.5! duerst 226: ** encoding (ACE, i.e. punicode).
! 227: ** Returns:
2.32.2.4 duerst 228: ** 0 Success
229: ** !=0 Error
230: */
231: PUBLIC int HTACEfromUTF8 (char *hostUTF8, char *punycode, size_t punyLength)
232: {
233: idn_result_t result;
234: char *hostNoPercent = (char *) HT_MALLOC(strlen(hostUTF8));
235: char *ptr, *ptr2;
236:
237: /* unescape %-escapes from URI */
238: for(ptr=hostUTF8, ptr2=hostNoPercent; *ptr; ) {
239: if (*ptr=='%' && isxdigit(*(ptr+1)) && isxdigit(*(ptr+2))) {
240: /* isxdigit() includes check for end of string */
241: unsigned char unesc = (unsigned char) (from_hex(*(ptr+1))*16 + from_hex(*(ptr+2)));
242: if (unesc=='.') *ptr2++ = *ptr++; /* just copy, because reserved, for security */
243: else {
244: *ptr2++ = (char) unesc;
245: ptr += 3;
246: }
247: } else *ptr2++ = *ptr++; /* just copy */
248: }
249: *ptr2=*ptr;
250:
251: /* still to do? check for valid UTF-8 */
252: /* maybe check for ASCII-only (efficiency?) */
253:
254: /* call ToASCII conversion (stringprep/nameprep) */
255: result = idn_encodename(IDN_ENCODE_QUERY&(~IDN_LOCALCONV),
256: hostNoPercent, punycode, punyLength);
257: if (result!=idn_success)
258: HTTRACE(PROT_TRACE, "IDN encoding not successful.\n");
259: HT_FREE(hostNoPercent);
260: return result;
261: }
262:
2.1 frystyk 263: /* HTGetHostByName
264: ** ---------------
265: ** Resolve the host name using internal DNS cache. As we want to refer
266: ** a specific host when timing the connection the weight function must
267: ** use the 'current' value as returned.
268: ** Returns:
269: ** >0 Number of homes
270: ** -1 Error
271: */
2.23 frystyk 272: PUBLIC int HTGetHostByName (HTHost * host, char *hostname, HTRequest* request)
2.1 frystyk 273: {
2.23 frystyk 274: SockA *sin = HTHost_getSockAddr(host);
2.1 frystyk 275: int homes = -1;
276: HTList *list; /* Current list in cache */
277: HTdns *pres = NULL;
2.32.2.3 duerst 278: char hostace[256]; /* check lengths!!! */
279:
2.23 frystyk 280: if (!host || !hostname) {
2.30 frystyk 281: HTTRACE(PROT_TRACE, "HostByName.. Bad argument\n");
2.1 frystyk 282: return -1;
283: }
2.23 frystyk 284: HTHost_setHome(host, 0);
2.1 frystyk 285:
2.32.2.4 duerst 286: if (HTACEfromUTF8 (hostname, hostace, 255)) {
287: /* deal with errors here */
2.32.2.2 duerst 288: }
2.32.2.1 duerst 289:
2.1 frystyk 290: /* Find a hash for this host */
291: {
292: int hash = 0;
293: char *ptr;
2.32.2.3 duerst 294: for(ptr=hostace; *ptr; ptr++)
2.29 frystyk 295: hash = (int) ((hash * 3 + (*(unsigned char *) ptr)) % HT_M_HASH_SIZE);
2.1 frystyk 296: if (!CacheTable) {
2.29 frystyk 297: if ((CacheTable = (HTList* *) HT_CALLOC(HT_M_HASH_SIZE, sizeof(HTList *))) == NULL)
2.17 frystyk 298: HT_OUTOFMEM("HTDNS_init");
2.1 frystyk 299: }
300: if (!CacheTable[hash]) CacheTable[hash] = HTList_new();
301: list = CacheTable[hash];
302: }
303:
304: /* Search the cache */
305: {
306: HTList *cur = list;
307: while ((pres = (HTdns *) HTList_nextObject(cur))) {
2.32.2.3 duerst 308: if (!strcmp(pres->hostname, hostace)) {
2.1 frystyk 309: if (time(NULL) > pres->ntime + DNSTimeout) {
2.30 frystyk 310: HTTRACE(PROT_TRACE, "HostByName.. Refreshing cache\n");
2.1 frystyk 311: delete_object(list, pres);
312: pres = NULL;
313: }
314: break;
315: }
316: }
317: }
318: if (pres) {
319: /*
320: ** Find the best home. We still want to do this as we use it as a
321: ** fall back for persistent connections
322: */
323: homes = pres->homes;
324: if (pres->homes > 1) {
325: int cnt = 0;
2.28 frystyk 326: double best_weight = 1e30; /* Pretty bad */
2.1 frystyk 327: while (cnt < pres->homes) {
328: if (*(pres->weight+cnt) < best_weight) {
329: best_weight = *(pres->weight+cnt);
2.23 frystyk 330: HTHost_setHome(host, cnt);
2.1 frystyk 331: }
332: cnt++;
333: }
334: }
2.23 frystyk 335: host->dns = pres;
336: memcpy((void *) &sin->sin_addr, *(pres->addrlist+HTHost_home(host)),
2.14 frystyk 337: pres->addrlength);
2.1 frystyk 338: } else {
339: struct hostent *hostelement; /* see netdb.h */
2.10 frystyk 340: HTAlertCallback *cbf = HTAlert_find(HT_PROG_DNS);
2.1 frystyk 341: #ifdef HT_REENTRANT
342: int thd_errno;
343: char buffer[HOSTENT_MAX];
344: struct hostent result; /* For gethostbyname_r */
2.31 kahan 345: #endif
2.32 kahan 346: #ifdef HAVE_GETHOSTBYNAME_R_3
2.31 kahan 347: struct hostent_data hdata;
348: #endif
349:
2.32.2.3 duerst 350: if (cbf) (*cbf)(request, HT_PROG_DNS, HT_MSG_NULL,NULL,hostace,NULL);
2.32 kahan 351: #ifdef HAVE_GETHOSTBYNAME_R_5
2.32.2.3 duerst 352: hostelement = gethostbyname_r(hostace, &result, buffer,
2.1 frystyk 353: HOSTENT_MAX, &thd_errno);
2.32 kahan 354: #elif defined(HAVE_GETHOSTBYNAME_R_6)
2.32.2.3 duerst 355: gethostbyname_r(hostace, &result, buffer,
2.31 kahan 356: HOSTENT_MAX, &hostelement, &thd_errno);
357:
2.32 kahan 358: #elif defined(HAVE_GETHOSTBYNAME_R_3)
2.32.2.3 duerst 359: if (gethostbyname_r(hostace, &result, &hdata) == 0) {
2.31 kahan 360: hostelement = &result;
361: }
362: else {
363: hostelement = NULL;
364: }
2.1 frystyk 365: #else
2.32.2.3 duerst 366: if (cbf) (*cbf)(request, HT_PROG_DNS, HT_MSG_NULL,NULL,hostace,NULL);
367: hostelement = gethostbyname(hostace);
2.1 frystyk 368: #endif
369: if (!hostelement) {
2.27 frystyk 370: HTRequest_addSystemError(request, ERR_FATAL, socerrno, NO,
371: "gethostbyname");
2.1 frystyk 372: return -1;
373: }
2.32.2.3 duerst 374: host->dns = HTDNS_add(list, hostelement, hostace, &homes);
2.14 frystyk 375: memcpy((void *) &sin->sin_addr, *hostelement->h_addr_list,
376: hostelement->h_length);
2.1 frystyk 377: }
378: return homes;
379: }
380:
381:
382: /*
383: ** Get host name of the machine on the other end of a socket.
384: **
385: */
2.9 frystyk 386: PUBLIC char * HTGetHostBySock (int soc)
2.1 frystyk 387: {
388: struct sockaddr addr;
389: int len = sizeof(struct sockaddr);
390: struct in_addr *iaddr;
391: char *name = NULL;
392: struct hostent * phost; /* Pointer to host -- See netdb.h */
393: #ifdef HT_REENTRANT
394: int thd_errno;
395: char buffer[HOSTENT_MAX];
396: struct hostent result; /* For gethostbyaddr_r */
397: #endif
2.31 kahan 398: #ifdef HAVE_GETHOSTBYADDR_R_5
399: struct hostent_data hdata;
400: #endif
2.1 frystyk 401:
402: #ifdef DECNET /* Decnet ain't got no damn name server 8#OO */
403: return NULL;
404: #else
405: if (getpeername(soc, &addr, &len) < 0)
406: return NULL;
407: iaddr = &(((struct sockaddr_in *)&addr)->sin_addr);
408:
2.31 kahan 409: #ifdef HAVE_GETHOSTBYADDR_R_7
2.1 frystyk 410: phost = gethostbyaddr_r((char *) iaddr, sizeof(struct in_addr), AF_INET,
411: &result, buffer, HOSTENT_MAX, &thd_errno);
2.31 kahan 412: #elif defined(HAVE_GETHOSTBYADDR_R_8)
413: gethostbyaddr_r((char *) iaddr, sizeof(struct in_addr), AF_INET,
414: &result, buffer, HOSTENT_MAX, &phost, &thd_errno);
415: #elif defined(HAVE_GETHOSTBYADDR_R_5)
416: if(gethostbyaddr_r((char *) iaddr, sizeof(struct in_addr), AF_INET,
417: &result, &hdata)==0) {
418: phost=&result;
419: }
420: else {
421: phost = NULL;
422: }
2.1 frystyk 423: #else
424: phost = gethostbyaddr((char *) iaddr, sizeof(struct in_addr), AF_INET);
425: #endif
426: if (!phost) {
2.30 frystyk 427: HTTRACE(PROT_TRACE, "TCP......... Can't find internet node name for peer!!\n");
2.1 frystyk 428: return NULL;
429: }
430: StrAllocCopy(name, phost->h_name);
2.30 frystyk 431: HTTRACE(PROT_TRACE, "TCP......... Peer name is `%s'\n" _ name);
2.1 frystyk 432: return name;
433:
434: #endif /* not DECNET */
435: }
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