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Annotation of 43BSDReno/usr.sbin/sendmail/src/domain.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1986 Eric P. Allman
        !             3:  * Copyright (c) 1988 Regents of the University of California.
        !             4:  * All rights reserved.
        !             5:  *
        !             6:  * Redistribution and use in source and binary forms are permitted provided
        !             7:  * that: (1) source distributions retain this entire copyright notice and
        !             8:  * comment, and (2) distributions including binaries display the following
        !             9:  * acknowledgement:  ``This product includes software developed by the
        !            10:  * University of California, Berkeley and its contributors'' in the
        !            11:  * documentation or other materials provided with the distribution and in
        !            12:  * all advertising materials mentioning features or use of this software.
        !            13:  * Neither the name of the University nor the names of its contributors may
        !            14:  * be used to endorse or promote products derived from this software without
        !            15:  * specific prior written permission.
        !            16:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            17:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            18:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            19:  */
        !            20: 
        !            21: #include "sendmail.h"
        !            22: 
        !            23: #ifndef lint
        !            24: #ifdef NAMED_BIND
        !            25: static char sccsid[] = "@(#)domain.c   5.22 (Berkeley) 6/1/90 (with name server)";
        !            26: #else
        !            27: static char sccsid[] = "@(#)domain.c   5.22 (Berkeley) 6/1/90 (without name server)";
        !            28: #endif
        !            29: #endif /* not lint */
        !            30: 
        !            31: #ifdef NAMED_BIND
        !            32: 
        !            33: #include <sys/param.h>
        !            34: #include <errno.h>
        !            35: #include <arpa/nameser.h>
        !            36: #include <resolv.h>
        !            37: #include <netdb.h>
        !            38: 
        !            39: typedef union {
        !            40:        HEADER qb1;
        !            41:        char qb2[PACKETSZ];
        !            42: } querybuf;
        !            43: 
        !            44: static char hostbuf[MAXMXHOSTS*PACKETSZ];
        !            45: 
        !            46: getmxrr(host, mxhosts, localhost, rcode)
        !            47:        char *host, **mxhosts, *localhost;
        !            48:        int *rcode;
        !            49: {
        !            50:        extern int h_errno;
        !            51:        register u_char *eom, *cp;
        !            52:        register int i, j, n, nmx;
        !            53:        register char *bp;
        !            54:        HEADER *hp;
        !            55:        querybuf answer;
        !            56:        int ancount, qdcount, buflen, seenlocal;
        !            57:        u_short pref, localpref, type, prefer[MAXMXHOSTS];
        !            58: 
        !            59:        errno = 0;
        !            60:        n = res_search(host, C_IN, T_MX, (char *)&answer, sizeof(answer));
        !            61:        if (n < 0)
        !            62:        {
        !            63:                if (tTd(8, 1))
        !            64:                        printf("getmxrr: res_search failed (errno=%d, h_errno=%d)\n",
        !            65:                            errno, h_errno);
        !            66:                switch (h_errno)
        !            67:                {
        !            68:                  case NO_DATA:
        !            69:                  case NO_RECOVERY:
        !            70:                        /* no MX data on this host */
        !            71:                        goto punt;
        !            72: 
        !            73:                  case HOST_NOT_FOUND:
        !            74:                        /* the host just doesn't exist */
        !            75:                        *rcode = EX_NOHOST;
        !            76:                        break;
        !            77: 
        !            78:                  case TRY_AGAIN:
        !            79:                        /* couldn't connect to the name server */
        !            80:                        if (!UseNameServer && errno == ECONNREFUSED)
        !            81:                                goto punt;
        !            82: 
        !            83:                        /* it might come up later; better queue it up */
        !            84:                        *rcode = EX_TEMPFAIL;
        !            85:                        break;
        !            86:                }
        !            87: 
        !            88:                /* irreconcilable differences */
        !            89:                return (-1);
        !            90:        }
        !            91: 
        !            92:        /* find first satisfactory answer */
        !            93:        hp = (HEADER *)&answer;
        !            94:        cp = (u_char *)&answer + sizeof(HEADER);
        !            95:        eom = (u_char *)&answer + n;
        !            96:        for (qdcount = ntohs(hp->qdcount); qdcount--; cp += n + QFIXEDSZ)
        !            97:                if ((n = dn_skipname(cp, eom)) < 0)
        !            98:                        goto punt;
        !            99:        nmx = 0;
        !           100:        seenlocal = 0;
        !           101:        buflen = sizeof(hostbuf);
        !           102:        bp = hostbuf;
        !           103:        ancount = ntohs(hp->ancount);
        !           104:        while (--ancount >= 0 && cp < eom && nmx < MAXMXHOSTS) {
        !           105:                if ((n = dn_expand((char *)&answer, eom, cp, bp, buflen)) < 0)
        !           106:                        break;
        !           107:                cp += n;
        !           108:                GETSHORT(type, cp);
        !           109:                cp += sizeof(u_short) + sizeof(u_long);
        !           110:                GETSHORT(n, cp);
        !           111:                if (type != T_MX)  {
        !           112:                        if (tTd(8, 1) || _res.options & RES_DEBUG)
        !           113:                                printf("unexpected answer type %d, size %d\n",
        !           114:                                    type, n);
        !           115:                        cp += n;
        !           116:                        continue;
        !           117:                }
        !           118:                GETSHORT(pref, cp);
        !           119:                if ((n = dn_expand((char *)&answer, eom, cp, bp, buflen)) < 0)
        !           120:                        break;
        !           121:                cp += n;
        !           122:                if (!strcasecmp(bp, localhost)) {
        !           123:                        if (seenlocal == 0 || pref < localpref)
        !           124:                                localpref = pref;
        !           125:                        seenlocal = 1;
        !           126:                        continue;
        !           127:                }
        !           128:                prefer[nmx] = pref;
        !           129:                mxhosts[nmx++] = bp;
        !           130:                n = strlen(bp) + 1;
        !           131:                bp += n;
        !           132:                buflen -= n;
        !           133:        }
        !           134:        if (nmx == 0) {
        !           135: punt:          mxhosts[0] = strcpy(hostbuf, host);
        !           136:                return(1);
        !           137:        }
        !           138: 
        !           139:        /* sort the records */
        !           140:        for (i = 0; i < nmx; i++) {
        !           141:                for (j = i + 1; j < nmx; j++) {
        !           142:                        if (prefer[i] > prefer[j] ||
        !           143:                            (prefer[i] == prefer[j] && rand() % 1 == 0)) {
        !           144:                                register int temp;
        !           145:                                register char *temp1;
        !           146: 
        !           147:                                temp = prefer[i];
        !           148:                                prefer[i] = prefer[j];
        !           149:                                prefer[j] = temp;
        !           150:                                temp1 = mxhosts[i];
        !           151:                                mxhosts[i] = mxhosts[j];
        !           152:                                mxhosts[j] = temp1;
        !           153:                        }
        !           154:                }
        !           155:                if (seenlocal && prefer[i] >= localpref) {
        !           156:                        /*
        !           157:                         * truncate higher pref part of list; if we're
        !           158:                         * the best choice left, we should have realized
        !           159:                         * awhile ago that this was a local delivery.
        !           160:                         */
        !           161:                        if (i == 0) {
        !           162:                                *rcode = EX_CONFIG;
        !           163:                                return(-1);
        !           164:                        }
        !           165:                        nmx = i;
        !           166:                        break;
        !           167:                }
        !           168:        }
        !           169:        return(nmx);
        !           170: }
        !           171: 
        !           172: getcanonname(host, hbsize)
        !           173:        char *host;
        !           174:        int hbsize;
        !           175: {
        !           176:        extern int h_errno;
        !           177:        register u_char *eom, *cp;
        !           178:        register int n; 
        !           179:        HEADER *hp;
        !           180:        querybuf answer;
        !           181:        u_short type;
        !           182:        int first, ancount, qdcount, loopcnt;
        !           183:        char nbuf[PACKETSZ];
        !           184: 
        !           185:        loopcnt = 0;
        !           186: loop:
        !           187:        /*
        !           188:         * Use query type of ANY if possible (NO_WILDCARD_MX), which will
        !           189:         * find types CNAME, A, and MX, and will cause all existing records
        !           190:         * to be cached by our local server.  If there is (might be) a
        !           191:         * wildcard MX record in the local domain or its parents that are
        !           192:         * searched, we can't use ANY; it would cause fully-qualified names
        !           193:         * to match as names in a local domain.
        !           194:         */
        !           195: # ifdef NO_WILDCARD_MX
        !           196:        n = res_search(host, C_IN, T_ANY, (char *)&answer, sizeof(answer));
        !           197: # else
        !           198:        n = res_search(host, C_IN, T_CNAME, (char *)&answer, sizeof(answer));
        !           199: # endif
        !           200:        if (n < 0) {
        !           201:                if (tTd(8, 1))
        !           202:                        printf("getcanonname:  res_search failed (errno=%d, h_errno=%d)\n",
        !           203:                            errno, h_errno);
        !           204:                return;
        !           205:        }
        !           206: 
        !           207:        /* find first satisfactory answer */
        !           208:        hp = (HEADER *)&answer;
        !           209:        ancount = ntohs(hp->ancount);
        !           210: 
        !           211:        /* we don't care about errors here, only if we got an answer */
        !           212:        if (ancount == 0) {
        !           213:                if (tTd(8, 1))
        !           214:                        printf("rcode = %d, ancount=%d\n", hp->rcode, ancount);
        !           215:                return;
        !           216:        }
        !           217:        cp = (u_char *)&answer + sizeof(HEADER);
        !           218:        eom = (u_char *)&answer + n;
        !           219:        for (qdcount = ntohs(hp->qdcount); qdcount--; cp += n + QFIXEDSZ)
        !           220:                if ((n = dn_skipname(cp, eom)) < 0)
        !           221:                        return;
        !           222: 
        !           223:        /*
        !           224:         * just in case someone puts a CNAME record after another record,
        !           225:         * check all records for CNAME; otherwise, just take the first
        !           226:         * name found.
        !           227:         */
        !           228:        for (first = 1; --ancount >= 0 && cp < eom; cp += n) {
        !           229:                if ((n = dn_expand((char *)&answer, eom, cp, nbuf,
        !           230:                    sizeof(nbuf))) < 0)
        !           231:                        break;
        !           232:                if (first) {                    /* XXX */
        !           233:                        (void)strncpy(host, nbuf, hbsize);
        !           234:                        host[hbsize - 1] = '\0';
        !           235:                        first = 0;
        !           236:                }
        !           237:                cp += n;
        !           238:                GETSHORT(type, cp);
        !           239:                cp += sizeof(u_short) + sizeof(u_long);
        !           240:                GETSHORT(n, cp);
        !           241:                if (type == T_CNAME)  {
        !           242:                        /*
        !           243:                         * assume that only one cname will be found.  More
        !           244:                         * than one is undefined.  Copy so that if dn_expand
        !           245:                         * fails, `host' is still okay.
        !           246:                         */
        !           247:                        if ((n = dn_expand((char *)&answer, eom, cp, nbuf,
        !           248:                            sizeof(nbuf))) < 0)
        !           249:                                break;
        !           250:                        (void)strncpy(host, nbuf, hbsize); /* XXX */
        !           251:                        host[hbsize - 1] = '\0';
        !           252:                        if (++loopcnt > 8)      /* never be more than 1 */
        !           253:                                return;
        !           254:                        goto loop;
        !           255:                }
        !           256:        }
        !           257: }
        !           258: 
        !           259: #else /* not NAMED_BIND */
        !           260: 
        !           261: #include <netdb.h>
        !           262: 
        !           263: getcanonname(host, hbsize)
        !           264:        char *host;
        !           265:        int hbsize;
        !           266: {
        !           267:        struct hostent *hp;
        !           268: 
        !           269:        hp = gethostbyname(host);
        !           270:        if (hp == NULL)
        !           271:                return;
        !           272: 
        !           273:        if (strlen(hp->h_name) >= hbsize)
        !           274:                return;
        !           275: 
        !           276:        (void) strcpy(host, hp->h_name);
        !           277: }
        !           278: 
        !           279: #endif /* not NAMED_BIND */

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