diff options
Diffstat (limited to 'src/domain.c')
| -rw-r--r-- | src/domain.c | 912 |
1 files changed, 0 insertions, 912 deletions
diff --git a/src/domain.c b/src/domain.c deleted file mode 100644 index ec79be8..0000000 --- a/src/domain.c +++ /dev/null @@ -1,912 +0,0 @@ -/* - * Copyright (c) 1998 Sendmail, Inc. All rights reserved. - * Copyright (c) 1986, 1995-1997 Eric P. Allman. All rights reserved. - * Copyright (c) 1988, 1993 - * The Regents of the University of California. All rights reserved. - * - * By using this file, you agree to the terms and conditions set - * forth in the LICENSE file which can be found at the top level of - * the sendmail distribution. - * - */ - -#include "sendmail.h" - -#ifndef lint -#if NAMED_BIND -static char sccsid[] = "@(#)domain.c 8.81 (Berkeley) 1/21/1999 (with name server)"; -#else -static char sccsid[] = "@(#)domain.c 8.81 (Berkeley) 1/21/1999 (without name server)"; -#endif -#endif /* not lint */ - -#if NAMED_BIND - -#include <errno.h> -#include <resolv.h> -#include <arpa/inet.h> - -/* -** The standard udp packet size PACKETSZ (512) is not sufficient for some -** nameserver answers containing very many resource records. The resolver -** may switch to tcp and retry if it detects udp packet overflow. -** Also note that the resolver routines res_query and res_search return -** the size of the *un*truncated answer in case the supplied answer buffer -** it not big enough to accommodate the entire answer. -*/ - -#ifndef MAXPACKET -# define MAXPACKET 8192 /* max packet size used internally by BIND */ -#endif - -typedef union -{ - HEADER qb1; - u_char qb2[MAXPACKET]; -} querybuf; - -#ifndef MXHOSTBUFSIZE -# define MXHOSTBUFSIZE (128 * MAXMXHOSTS) -#endif - -static char MXHostBuf[MXHOSTBUFSIZE]; - -#ifndef MAXDNSRCH -# define MAXDNSRCH 6 /* number of possible domains to search */ -#endif - -#ifndef MAX -# define MAX(a, b) ((a) > (b) ? (a) : (b)) -#endif - -#ifndef NO_DATA -# define NO_DATA NO_ADDRESS -#endif - -#ifndef HFIXEDSZ -# define HFIXEDSZ 12 /* sizeof(HEADER) */ -#endif - -#define MAXCNAMEDEPTH 10 /* maximum depth of CNAME recursion */ - -#if defined(__RES) && (__RES >= 19940415) -# define RES_UNC_T char * -#else -# define RES_UNC_T u_char * -#endif - /* -** GETMXRR -- get MX resource records for a domain -** -** Parameters: -** host -- the name of the host to MX. -** mxhosts -- a pointer to a return buffer of MX records. -** droplocalhost -- If TRUE, all MX records less preferred -** than the local host (as determined by $=w) will -** be discarded. -** rcode -- a pointer to an EX_ status code. -** -** Returns: -** The number of MX records found. -** -1 if there is an internal failure. -** If no MX records are found, mxhosts[0] is set to host -** and 1 is returned. -*/ - -int -getmxrr(host, mxhosts, droplocalhost, rcode) - char *host; - char **mxhosts; - bool droplocalhost; - int *rcode; -{ - register u_char *eom, *cp; - register int i, j, n; - int nmx = 0; - register char *bp; - HEADER *hp; - querybuf answer; - int ancount, qdcount, buflen; - bool seenlocal = FALSE; - u_short pref, type; - u_short localpref = 256; - char *fallbackMX = FallBackMX; - bool trycanon = FALSE; - int (*resfunc)(); - extern int res_query(), res_search(); - u_short prefer[MAXMXHOSTS]; - int weight[MAXMXHOSTS]; - extern int mxrand __P((char *)); - - if (tTd(8, 2)) - printf("getmxrr(%s, droplocalhost=%d)\n", host, droplocalhost); - - if (fallbackMX != NULL && droplocalhost && - wordinclass(fallbackMX, 'w')) - { - /* don't use fallback for this pass */ - fallbackMX = NULL; - } - - *rcode = EX_OK; - - /* efficiency hack -- numeric or non-MX lookups */ - if (host[0] == '[') - goto punt; - - /* - ** If we don't have MX records in our host switch, don't - ** try for MX records. Note that this really isn't "right", - ** since we might be set up to try NIS first and then DNS; - ** if the host is found in NIS we really shouldn't be doing - ** MX lookups. However, that should be a degenerate case. - */ - - if (!UseNameServer) - goto punt; - if (HasWildcardMX && ConfigLevel >= 6) - resfunc = res_query; - else - resfunc = res_search; - - errno = 0; - n = (*resfunc)(host, C_IN, T_MX, (u_char *) &answer, sizeof(answer)); - if (n < 0) - { - if (tTd(8, 1)) - printf("getmxrr: res_search(%s) failed (errno=%d, h_errno=%d)\n", - (host == NULL) ? "<NULL>" : host, errno, h_errno); - switch (h_errno) - { - case NO_DATA: - trycanon = TRUE; - /* fall through */ - - case NO_RECOVERY: - /* no MX data on this host */ - goto punt; - - case HOST_NOT_FOUND: -#if BROKEN_RES_SEARCH - case 0: /* Ultrix resolver retns failure w/ h_errno=0 */ -#endif - /* host doesn't exist in DNS; might be in /etc/hosts */ - trycanon = TRUE; - *rcode = EX_NOHOST; - goto punt; - - case TRY_AGAIN: - case -1: - /* couldn't connect to the name server */ - if (fallbackMX != NULL) - { - /* name server is hosed -- push to fallback */ - mxhosts[nmx++] = fallbackMX; - return nmx; - } - /* it might come up later; better queue it up */ - *rcode = EX_TEMPFAIL; - break; - - default: - syserr("getmxrr: res_search (%s) failed with impossible h_errno (%d)\n", - host, h_errno); - *rcode = EX_OSERR; - break; - } - - /* irreconcilable differences */ - return (-1); - } - - /* avoid problems after truncation in tcp packets */ - if (n > sizeof(answer)) - n = sizeof(answer); - - /* find first satisfactory answer */ - hp = (HEADER *)&answer; - cp = (u_char *)&answer + HFIXEDSZ; - eom = (u_char *)&answer + n; - for (qdcount = ntohs(hp->qdcount); qdcount--; cp += n + QFIXEDSZ) - if ((n = dn_skipname(cp, eom)) < 0) - goto punt; - buflen = sizeof(MXHostBuf) - 1; - bp = MXHostBuf; - ancount = ntohs(hp->ancount); - while (--ancount >= 0 && cp < eom && nmx < MAXMXHOSTS - 1) - { - if ((n = dn_expand((u_char *)&answer, - eom, cp, (RES_UNC_T) bp, buflen)) < 0) - break; - cp += n; - GETSHORT(type, cp); - cp += INT16SZ + INT32SZ; - GETSHORT(n, cp); - if (type != T_MX) - { - if (tTd(8, 8) || _res.options & RES_DEBUG) - printf("unexpected answer type %d, size %d\n", - type, n); - cp += n; - continue; - } - GETSHORT(pref, cp); - if ((n = dn_expand((u_char *)&answer, eom, cp, - (RES_UNC_T) bp, buflen)) < 0) - break; - cp += n; - if (wordinclass(bp, 'w')) - { - if (tTd(8, 3)) - printf("found localhost (%s) in MX list, pref=%d\n", - bp, pref); - if (droplocalhost) - { - if (!seenlocal || pref < localpref) - localpref = pref; - seenlocal = TRUE; - continue; - } - weight[nmx] = 0; - } - else - weight[nmx] = mxrand(bp); - prefer[nmx] = pref; - mxhosts[nmx++] = bp; - n = strlen(bp); - bp += n; - if (bp[-1] != '.') - { - *bp++ = '.'; - n++; - } - *bp++ = '\0'; - buflen -= n + 1; - } - - /* sort the records */ - for (i = 0; i < nmx; i++) - { - for (j = i + 1; j < nmx; j++) - { - if (prefer[i] > prefer[j] || - (prefer[i] == prefer[j] && weight[i] > weight[j])) - { - register int temp; - register char *temp1; - - temp = prefer[i]; - prefer[i] = prefer[j]; - prefer[j] = temp; - temp1 = mxhosts[i]; - mxhosts[i] = mxhosts[j]; - mxhosts[j] = temp1; - temp = weight[i]; - weight[i] = weight[j]; - weight[j] = temp; - } - } - if (seenlocal && prefer[i] >= localpref) - { - /* truncate higher preference part of list */ - nmx = i; - } - } - - /* delete duplicates from list (yes, some bozos have duplicates) */ - for (i = 0; i < nmx - 1; ) - { - if (strcasecmp(mxhosts[i], mxhosts[i + 1]) != 0) - i++; - else - { - /* compress out duplicate */ - for (j = i + 1; j < nmx; j++) - mxhosts[j] = mxhosts[j + 1]; - nmx--; - } - } - - if (nmx == 0) - { -punt: - if (seenlocal && - (!TryNullMXList || sm_gethostbyname(host) == NULL)) - { - /* - ** If we have deleted all MX entries, this is - ** an error -- we should NEVER send to a host that - ** has an MX, and this should have been caught - ** earlier in the config file. - ** - ** Some sites prefer to go ahead and try the - ** A record anyway; that case is handled by - ** setting TryNullMXList. I believe this is a - ** bad idea, but it's up to you.... - */ - - *rcode = EX_CONFIG; - syserr("MX list for %s points back to %s", - host, MyHostName); - return -1; - } - if (strlen(host) >= (SIZE_T) sizeof MXHostBuf) - { - *rcode = EX_CONFIG; - syserr("Host name %s too long", - shortenstring(host, MAXSHORTSTR)); - return -1; - } - snprintf(MXHostBuf, sizeof MXHostBuf, "%s", host); - mxhosts[0] = MXHostBuf; - if (host[0] == '[') - { - register char *p; - - /* this may be an MX suppression-style address */ - p = strchr(MXHostBuf, ']'); - if (p != NULL) - { - *p = '\0'; - if (inet_addr(&MXHostBuf[1]) != INADDR_NONE) - { - nmx++; - *p = ']'; - } - else - { - trycanon = TRUE; - mxhosts[0]++; - } - } - } - if (trycanon && - getcanonname(mxhosts[0], sizeof MXHostBuf - 2, FALSE)) - { - bp = &MXHostBuf[strlen(MXHostBuf)]; - if (bp[-1] != '.') - { - *bp++ = '.'; - *bp = '\0'; - } - nmx = 1; - } - } - - /* if we have a default lowest preference, include that */ - if (fallbackMX != NULL && !seenlocal) - mxhosts[nmx++] = fallbackMX; - - return (nmx); -} - /* -** MXRAND -- create a randomizer for equal MX preferences -** -** If two MX hosts have equal preferences we want to randomize -** the selection. But in order for signatures to be the same, -** we need to randomize the same way each time. This function -** computes a pseudo-random hash function from the host name. -** -** Parameters: -** host -- the name of the host. -** -** Returns: -** A random but repeatable value based on the host name. -** -** Side Effects: -** none. -*/ - -int -mxrand(host) - register char *host; -{ - int hfunc; - static unsigned int seed; - - if (seed == 0) - { - seed = (int) curtime() & 0xffff; - if (seed == 0) - seed++; - } - - if (tTd(17, 9)) - printf("mxrand(%s)", host); - - hfunc = seed; - while (*host != '\0') - { - int c = *host++; - - if (isascii(c) && isupper(c)) - c = tolower(c); - hfunc = ((hfunc << 1) ^ c) % 2003; - } - - hfunc &= 0xff; - hfunc++; - - if (tTd(17, 9)) - printf(" = %d\n", hfunc); - return hfunc; -} - /* -** BESTMX -- find the best MX for a name -** -** This is really a hack, but I don't see any obvious way -** to generalize it at the moment. -*/ - -/* ARGSUSED3 */ -char * -bestmx_map_lookup(map, name, av, statp) - MAP *map; - char *name; - char **av; - int *statp; -{ - int nmx; - int saveopts = _res.options; - int i, len = 0; - char *p; - char *mxhosts[MAXMXHOSTS + 1]; - char buf[PSBUFSIZE / 2]; - - _res.options &= ~(RES_DNSRCH|RES_DEFNAMES); - nmx = getmxrr(name, mxhosts, FALSE, statp); - _res.options = saveopts; - if (nmx <= 0) - return NULL; - if (bitset(MF_MATCHONLY, map->map_mflags)) - return map_rewrite(map, name, strlen(name), NULL); - if ((map->map_coldelim == '\0') || (nmx == 1)) - return map_rewrite(map, mxhosts[0], strlen(mxhosts[0]), av); - - /* - ** We were given a -z flag (return all MXs) and there are multiple - ** ones. We need to build them all into a list. - */ - p = buf; - for (i = 0; i < nmx; i++) - { - int slen; - - if (strchr(mxhosts[i], map->map_coldelim) != NULL) - { - syserr("bestmx_map_lookup: MX host %.64s includes map delimiter character 0x%02X", - mxhosts[i], map->map_coldelim); - return NULL; - } - slen = strlen(mxhosts[i]); - if (len + slen + 2 > sizeof buf) - break; - if (i > 0) - { - *p++ = map->map_coldelim; - len++; - } - strcpy(p, mxhosts[i]); - p += slen; - len += slen; - } - return map_rewrite(map, buf, len, av); -} - /* -** DNS_GETCANONNAME -- get the canonical name for named host using DNS -** -** This algorithm tries to be smart about wildcard MX records. -** This is hard to do because DNS doesn't tell is if we matched -** against a wildcard or a specific MX. -** -** We always prefer A & CNAME records, since these are presumed -** to be specific. -** -** If we match an MX in one pass and lose it in the next, we use -** the old one. For example, consider an MX matching *.FOO.BAR.COM. -** A hostname bletch.foo.bar.com will match against this MX, but -** will stop matching when we try bletch.bar.com -- so we know -** that bletch.foo.bar.com must have been right. This fails if -** there was also an MX record matching *.BAR.COM, but there are -** some things that just can't be fixed. -** -** Parameters: -** host -- a buffer containing the name of the host. -** This is a value-result parameter. -** hbsize -- the size of the host buffer. -** trymx -- if set, try MX records as well as A and CNAME. -** statp -- pointer to place to store status. -** -** Returns: -** TRUE -- if the host matched. -** FALSE -- otherwise. -*/ - -bool -dns_getcanonname(host, hbsize, trymx, statp) - char *host; - int hbsize; - bool trymx; - int *statp; -{ - register u_char *eom, *ap; - register char *cp; - register int n; - HEADER *hp; - querybuf answer; - int ancount, qdcount; - int ret; - char **domain; - int type; - char **dp; - char *mxmatch; - bool amatch; - bool gotmx = FALSE; - int qtype; - int loopcnt; - char *xp; - char nbuf[MAX(MAXPACKET, MAXDNAME*2+2)]; - char *searchlist[MAXDNSRCH+2]; - extern char *gethostalias __P((char *)); - - if (tTd(8, 2)) - printf("dns_getcanonname(%s, trymx=%d)\n", host, trymx); - - if ((_res.options & RES_INIT) == 0 && res_init() == -1) - { - *statp = EX_UNAVAILABLE; - return FALSE; - } - - /* - ** Initialize domain search list. If there is at least one - ** dot in the name, search the unmodified name first so we - ** find "vse.CS" in Czechoslovakia instead of in the local - ** domain (e.g., vse.CS.Berkeley.EDU). - ** - ** Older versions of the resolver could create this - ** list by tearing apart the host name. - */ - - loopcnt = 0; -cnameloop: - /* Check for dots in the name */ - for (cp = host, n = 0; *cp != '\0'; cp++) - if (*cp == '.') - n++; - - /* - ** If this is a simple name, determine whether it matches an - ** alias in the file defined by the environment variable HOSTALIASES. - */ - if (n == 0 && (xp = gethostalias(host)) != NULL) - { - if (loopcnt++ > MAXCNAMEDEPTH) - { - syserr("loop in ${HOSTALIASES} file"); - } - else - { - strncpy(host, xp, hbsize); - host[hbsize - 1] = '\0'; - goto cnameloop; - } - } - - /* - ** Build the search list. - ** If there is at least one dot in name, start with a null - ** domain to search the unmodified name first. - ** If name does not end with a dot and search up local domain - ** tree desired, append each local domain component to the - ** search list; if name contains no dots and default domain - ** name is desired, append default domain name to search list; - ** else if name ends in a dot, remove that dot. - */ - - dp = searchlist; - if (n > 0) - *dp++ = ""; - if (n >= 0 && *--cp != '.' && bitset(RES_DNSRCH, _res.options)) - { - for (domain = _res.dnsrch; *domain != NULL; ) - *dp++ = *domain++; - } - else if (n == 0 && bitset(RES_DEFNAMES, _res.options)) - { - *dp++ = _res.defdname; - } - else if (*cp == '.') - { - *cp = '\0'; - } - *dp = NULL; - - /* - ** Now loop through the search list, appending each domain in turn - ** name and searching for a match. - */ - - mxmatch = NULL; - qtype = T_ANY; - - for (dp = searchlist; *dp != NULL; ) - { - if (qtype == T_ANY) - gotmx = FALSE; - if (tTd(8, 5)) - printf("dns_getcanonname: trying %s.%s (%s)\n", - host, *dp, - qtype == T_ANY ? "ANY" : qtype == T_A ? "A" : - qtype == T_MX ? "MX" : "???"); - ret = res_querydomain(host, *dp, C_IN, qtype, - answer.qb2, sizeof(answer.qb2)); - if (ret <= 0) - { - if (tTd(8, 7)) - printf("\tNO: errno=%d, h_errno=%d\n", - errno, h_errno); - - if (errno == ECONNREFUSED || h_errno == TRY_AGAIN) - { - /* the name server seems to be down */ - h_errno = TRY_AGAIN; - *statp = EX_TEMPFAIL; - return FALSE; - } - - if (h_errno != HOST_NOT_FOUND) - { - /* might have another type of interest */ - if (qtype == T_ANY) - { - qtype = T_A; - continue; - } - else if (qtype == T_A && !gotmx && (trymx || **dp == '\0')) - { - qtype = T_MX; - continue; - } - } - - /* definite no -- try the next domain */ - dp++; - qtype = T_ANY; - continue; - } - else if (tTd(8, 7)) - printf("\tYES\n"); - - /* avoid problems after truncation in tcp packets */ - if (ret > sizeof(answer)) - ret = sizeof(answer); - - /* - ** Appear to have a match. Confirm it by searching for A or - ** CNAME records. If we don't have a local domain - ** wild card MX record, we will accept MX as well. - */ - - hp = (HEADER *) &answer; - ap = (u_char *) &answer + HFIXEDSZ; - eom = (u_char *) &answer + ret; - - /* skip question part of response -- we know what we asked */ - for (qdcount = ntohs(hp->qdcount); qdcount--; ap += ret + QFIXEDSZ) - { - if ((ret = dn_skipname(ap, eom)) < 0) - { - if (tTd(8, 20)) - printf("qdcount failure (%d)\n", - ntohs(hp->qdcount)); - *statp = EX_SOFTWARE; - return FALSE; /* ???XXX??? */ - } - } - - amatch = FALSE; - for (ancount = ntohs(hp->ancount); --ancount >= 0 && ap < eom; - ap += n) - { - n = dn_expand((u_char *) &answer, eom, ap, - (RES_UNC_T) nbuf, sizeof nbuf); - if (n < 0) - break; - ap += n; - GETSHORT(type, ap); - ap += INT16SZ + INT32SZ; - GETSHORT(n, ap); - switch (type) - { - case T_MX: - gotmx = TRUE; - if (**dp != '\0' && HasWildcardMX) - { - /* - ** If we are using MX matches and have - ** not yet gotten one, save this one - ** but keep searching for an A or - ** CNAME match. - */ - - if (trymx && mxmatch == NULL) - mxmatch = *dp; - continue; - } - - /* - ** If we did not append a domain name, this - ** must have been a canonical name to start - ** with. Even if we did append a domain name, - ** in the absence of a wildcard MX this must - ** still be a real MX match. - ** Such MX matches are as good as an A match, - ** fall through. - */ - - case T_A: - /* Flag that a good match was found */ - amatch = TRUE; - - /* continue in case a CNAME also exists */ - continue; - - case T_CNAME: - if (DontExpandCnames) - { - /* got CNAME -- guaranteed canonical */ - amatch = TRUE; - break; - } - - if (loopcnt++ > MAXCNAMEDEPTH) - { - /*XXX should notify postmaster XXX*/ - message("DNS failure: CNAME loop for %s", - host); - if (CurEnv->e_message == NULL) - { - char ebuf[MAXLINE]; - - snprintf(ebuf, sizeof ebuf, - "Deferred: DNS failure: CNAME loop for %.100s", - host); - CurEnv->e_message = newstr(ebuf); - } - h_errno = NO_RECOVERY; - *statp = EX_CONFIG; - return FALSE; - } - - /* value points at name */ - if ((ret = dn_expand((u_char *)&answer, - eom, ap, (RES_UNC_T) nbuf, sizeof(nbuf))) < 0) - break; - (void)strncpy(host, nbuf, hbsize); /* XXX */ - host[hbsize - 1] = '\0'; - - /* - ** RFC 1034 section 3.6 specifies that CNAME - ** should point at the canonical name -- but - ** urges software to try again anyway. - */ - - goto cnameloop; - - default: - /* not a record of interest */ - continue; - } - } - - if (amatch) - { - /* - ** Got a good match -- either an A, CNAME, or an - ** exact MX record. Save it and get out of here. - */ - - mxmatch = *dp; - break; - } - - /* - ** Nothing definitive yet. - ** If this was a T_ANY query, we don't really know what - ** was returned -- it might have been a T_NS, - ** for example. Try T_A to be more specific - ** during the next pass. - ** If this was a T_A query and we haven't yet found a MX - ** match, try T_MX if allowed to do so. - ** Otherwise, try the next domain. - */ - - if (qtype == T_ANY) - qtype = T_A; - else if (qtype == T_A && !gotmx && (trymx || **dp == '\0')) - qtype = T_MX; - else - { - qtype = T_ANY; - dp++; - } - } - - /* if nothing was found, we are done */ - if (mxmatch == NULL) - { - *statp = EX_NOHOST; - return FALSE; - } - - /* - ** Create canonical name and return. - ** If saved domain name is null, name was already canonical. - ** Otherwise append the saved domain name. - */ - - (void) snprintf(nbuf, sizeof nbuf, "%.*s%s%.*s", MAXDNAME, host, - *mxmatch == '\0' ? "" : ".", - MAXDNAME, mxmatch); - strncpy(host, nbuf, hbsize); - host[hbsize - 1] = '\0'; - if (tTd(8, 5)) - printf("dns_getcanonname: %s\n", host); - *statp = EX_OK; - return TRUE; -} - - - -char * -gethostalias(host) - char *host; -{ - char *fname; - FILE *fp; - register char *p = NULL; - int sff = SFF_REGONLY; - char buf[MAXLINE]; - static char hbuf[MAXDNAME]; - - if (DontLockReadFiles) - sff |= SFF_NOLOCK; - fname = getenv("HOSTALIASES"); - if (fname == NULL || - (fp = safefopen(fname, O_RDONLY, 0, sff)) == NULL) - return NULL; - while (fgets(buf, sizeof buf, fp) != NULL) - { - for (p = buf; p != '\0' && !(isascii(*p) && isspace(*p)); p++) - continue; - if (*p == 0) - { - /* syntax error */ - continue; - } - *p++ = '\0'; - if (strcasecmp(buf, host) == 0) - break; - } - - if (feof(fp)) - { - /* no match */ - fclose(fp); - return NULL; - } - fclose(fp); - - /* got a match; extract the equivalent name */ - while (*p != '\0' && isascii(*p) && isspace(*p)) - p++; - host = p; - while (*p != '\0' && !(isascii(*p) && isspace(*p))) - p++; - *p = '\0'; - strncpy(hbuf, host, sizeof hbuf - 1); - hbuf[sizeof hbuf - 1] = '\0'; - return hbuf; -} - -#endif /* NAMED_BIND */ |