BOOL GetMX (
char *pszQuery,
char *pszServer,
OUT t_Ary_MXHostInfos &Ary_MXHostInfos
)
{
SOCKET hSocket;
SOCKADDR_IN stSockAddr; // socket address structures
int nAddrLen = sizeof( SOCKADDR_IN );
HOSTENT *pHostEnt;
char achBufOut[ BUFSIZE ] = { 0 };
char achBufIn[ BUFSIZE ] = { 0 };
int nQueryLen = 0;
int nRC;
char *p, *np, name[128], *eom;
int count, j, i, n;
memset( &stSockAddr, ASCII_NULL, sizeof( stSockAddr ) );
stSockAddr.sin_family = AF_INET;
stSockAddr.sin_port = htons( 53);
stSockAddr.sin_addr.s_addr = inet_addr( pszServer );
if ( stSockAddr.sin_addr.s_addr == INADDR_NONE )
{
pHostEnt = gethostbyname( pszServer );
if ( pHostEnt )
{
stSockAddr.sin_addr.s_addr = *((ULONG *)pHostEnt->h_addr_list[0]);
}
else
{
return FALSE;
} // end if
} // end if
/*------------------------------------------------------------
* Get a DGRAM socket
*/
hSocket = socket( AF_INET, SOCK_DGRAM, 0 );
if ( hSocket == INVALID_SOCKET )
{
return FALSE;
} // end if
/*-----------------------------------------------------------
* Format DNS Query
*/
pDNShdr = (PDNS_HDR)&( achBufOut[ 0 ] );
pDNShdr->dns_id = htons( 0xDEAD );
pDNShdr->dns_flags = htons( DNS_FLAG_RD ); // do recurse
pDNShdr->dns_q_count = htons( 1 ); // one query
pDNShdr->dns_rr_count = 0; // none in query
pDNShdr->dns_auth_count = 0; // none in query
pDNShdr->dns_add_count = 0; // none in query
nQueryLen = PutQName( pszQuery, &(achBufOut[ DNS_HDR_LEN ] ) );
nQueryLen += DNS_HDR_LEN;
achBufOut[ nQueryLen++ ] = 0;
achBufOut[ nQueryLen++ ] = 0;
achBufOut[ nQueryLen ] = DNS_RRTYPE_MX;
achBufOut[ nQueryLen + 1 ] = 0;
achBufOut[ nQueryLen + 2 ] = DNS_RRCLASS_IN;
achBufOut[ nQueryLen + 3 ] = 0;
nQueryLen += 4;
/*-----------------------------------------------------------
* Send DNS Query to server
*/
nRC = sendto( hSocket,
achBufOut,
nQueryLen,
0,
(LPSOCKADDR)&stSockAddr,
sizeof( SOCKADDR_IN ) );
if ( nRC == SOCKET_ERROR )
{
closesocket( hSocket );
return FALSE;
}
else
{
}
// VERIFY ( SetBlockingMode ( hSocket, TRUE ) );
// 用 select 模型实现连接超时
struct timeval timeout;
fd_set r;
FD_ZERO(&r);
FD_SET(hSocket, &r);
timeout.tv_sec = 5; //连接超时秒
timeout.tv_usec =0;
int ret = select(0, &r, 0, 0, &timeout);
if ( ret == SOCKET_ERROR )
{
::closesocket(hSocket);
hSocket = SOCKET_ERROR;
return FALSE;
}
// 得到可读的数据长度
long cmd = FIONREAD;
u_long argp = 0;
BOOL err = ioctlsocket ( hSocket, cmd, (u_long*)&argp );
if ( err || argp < 1 )
{
::closesocket(hSocket);
hSocket = SOCKET_ERROR;
return FALSE;
}
nRC = recvfrom( hSocket,
achBufIn,
BUFSIZE,
0,
(LPSOCKADDR)&stSockAddr,
&nAddrLen );
if ( nRC == SOCKET_ERROR )
{
int nWSAErr = WSAGetLastError();
if ( nWSAErr != WSAETIMEDOUT )
{
closesocket( hSocket );
return FALSE;
}
else
{
closesocket( hSocket );
return FALSE;
}
}
else
{
pDNShdr = (PDNS_HDR)&( achBufIn[ 0 ] );
p = (char *)&pDNShdr[0];
p+=12;
count = (int)*p;
// Parse the Question...
for (i = 0; i< ntohs(pDNShdr->dns_q_count); i++)
{
np = name;
eom = (char *)pDNShdr+nRC;
if ( (n = dn_expand((char *)pDNShdr, eom, p, name, 127)) < 0 )
{
return FALSE;
}
p += n + QFIXEDSZ;
}
for (i = 0; i< ntohs(pDNShdr->dns_rr_count); i++)
{
// The Question Name appears Again...
if ((n = dn_expand((char *)pDNShdr, eom, p, name, 127)) < 0)
{
return FALSE;
}
p+=n;
j = _getshort(p);; //TYPE
p+=2;
//printf("%s\tType:%d", name, j);
j = _getshort(p); //CLASS
p+=2;
// printf("\tClass:%d", j);
j = _getlong(p); //TTL
p+=4;
// printf("\tTTL:%d", j);
j = _getshort(p); //RDLENGTH
p+=2;
// printf("\tRDLENGTH:%d", j);
j = _getshort(p); //N??
p+=2;
// This should be an MX Name...
if ( (n = dn_expand((char *)pDNShdr, eom, p, name, 127)) < 0 )
{
return FALSE;
}
t_MXHostInfo tMXHostInfo = {0};
strncpy ( (char*)tMXHostInfo.szMXHost, name, _countof(tMXHostInfo.szMXHost));
tMXHostInfo.N = j;
Ary_MXHostInfos.Add ( tMXHostInfo );
TRACE ( _T("%s\t%d\r\n"), name, j );
p += n;
}
return TRUE;
}
closesocket( hSocket );
return FALSE;
}
/*
* Print resource record fields in human readable form.
*/
static char *
p_rr(char *cp, char *msg, FILE *file)
{
int type, class, dlen, n, c;
struct in_addr inaddr;
char *cp1, *cp2;
if ((cp = p_cdname(cp, msg, file)) == NULL)
return (NULL); /* compression error */
fprintf(file,"\n\ttype = %s", __p_type(type = _getshort(cp)));
cp += sizeof(u_short);
fprintf(file,", class = %s", __p_class(class = _getshort(cp)));
cp += sizeof(u_short);
fprintf(file,", ttl = %s", __p_time(_getlong(cp)));
cp += sizeof(u_long);
fprintf(file,", dlen = %d\n", dlen = _getshort(cp));
cp += sizeof(u_short);
cp1 = cp;
/*
* Print type specific data, if appropriate
*/
switch (type) {
case T_A:
switch (class) {
case C_IN:
case C_HS:
bcopy(cp, (char *)&inaddr, sizeof(inaddr));
if (dlen == 4) {
fprintf(file,"\tinternet address = %s\n",
inet_ntoa(inaddr));
cp += dlen;
} else if (dlen == 7) {
fprintf(file,"\tinternet address = %s",
inet_ntoa(inaddr));
fprintf(file,", protocol = %d", cp[4]);
fprintf(file,", port = %d\n",
(cp[5] << 8) + cp[6]);
cp += dlen;
}
break;
default:
cp += dlen;
}
break;
case T_CNAME:
case T_MB:
case T_MG:
case T_MR:
case T_NS:
case T_PTR:
fprintf(file,"\tdomain name = ");
cp = p_cdname(cp, msg, file);
fprintf(file,"\n");
break;
case T_HINFO:
if (n = *cp++) {
fprintf(file,"\tCPU=%.*s\n", n, cp);
cp += n;
}
if (n = *cp++) {
fprintf(file,"\tOS=%.*s\n", n, cp);
cp += n;
}
break;
case T_SOA:
fprintf(file,"\torigin = ");
cp = p_cdname(cp, msg, file);
fprintf(file,"\n\tmail addr = ");
cp = p_cdname(cp, msg, file);
fprintf(file,"\n\tserial = %ld", _getlong(cp));
cp += sizeof(u_long);
fprintf(file,"\n\trefresh = %s", __p_time(_getlong(cp)));
cp += sizeof(u_long);
fprintf(file,"\n\tretry = %s", __p_time(_getlong(cp)));
cp += sizeof(u_long);
fprintf(file,"\n\texpire = %s", __p_time(_getlong(cp)));
cp += sizeof(u_long);
fprintf(file,"\n\tmin = %s\n", __p_time(_getlong(cp)));
cp += sizeof(u_long);
break;
case T_MX:
fprintf(file,"\tpreference = %ld,",_getshort(cp));
cp += sizeof(u_short);
fprintf(file," name = ");
cp = p_cdname(cp, msg, file);
break;
case T_TXT:
(void) fputs("\t\"", file);
cp2 = cp1 + dlen;
while (cp < cp2) {
if (n = (unsigned char) *cp++) {
for (c = n; c > 0 && cp < cp2; c--)
if (*cp == '\n') {
(void) putc('\\', file);
(void) putc(*cp++, file);
} else
(void) putc(*cp++, file);
}
}
(void) fputs("\"\n", file);
break;
case T_MINFO:
fprintf(file,"\trequests = ");
cp = p_cdname(cp, msg, file);
fprintf(file,"\n\terrors = ");
cp = p_cdname(cp, msg, file);
break;
case T_UINFO:
fprintf(file,"\t%s\n", cp);
cp += dlen;
break;
case T_UID:
case T_GID:
if (dlen == 4) {
fprintf(file,"\t%ld\n", _getlong(cp));
cp += sizeof(int);
}
break;
case T_WKS:
if (dlen < sizeof(u_long) + 1)
break;
bcopy(cp, (char *)&inaddr, sizeof(inaddr));
cp += sizeof(u_long);
fprintf(file,"\tinternet address = %s, protocol = %d\n\t",
inet_ntoa(inaddr), *cp++);
n = 0;
while (cp < cp1 + dlen) {
c = *cp++;
do {
if (c & 0200)
fprintf(file," %d", n);
c <<= 1;
} while (++n & 07);
}
putc('\n',file);
break;
#ifdef ALLOW_T_UNSPEC
case T_UNSPEC:
{
int NumBytes = 8;
char *DataPtr;
int i;
if (dlen < NumBytes) NumBytes = dlen;
fprintf(file, "\tFirst %d bytes of hex data:",
NumBytes);
for (i = 0, DataPtr = cp; i < NumBytes; i++, DataPtr++)
fprintf(file, " %x", *DataPtr);
fputs("\n", file);
cp += dlen;
}
break;
#endif /* ALLOW_T_UNSPEC */
default:
fprintf(file,"\t???\n");
cp += dlen;
}
if (cp != cp1 + dlen) {
fprintf(file,"packet size error (%#x != %#x)\n", cp, cp1+dlen);
cp = NULL;
}
fprintf(file,"\n");
return (cp);
}
/*
* parse_rr:
* Extract and parse a resource record
*
* returns a pointer to the RR (or NULL on failure).
*/
s_rr *
parse_rr(
char **cpp,
char *msg)
{
s_rr *ptr;
int dlen;
union u_rdata *rd;
/*
* Set up the RR-independent information
*/
if ((ptr = (s_rr *)malloc(sizeof(s_rr))) == NULL )
return(NULL);
if ((ptr->name = expand_cdname(cpp,msg)) == NULL ) {
free(ptr);
return(NULL);
}
ptr->type = _getshort(*cpp);
*cpp += sizeof(u_short);
ptr->rclass = _getshort(*cpp);
*cpp += sizeof(u_short);
ptr->ttl = _getlong(*cpp);
/* Size on the network is 4 bytes so use u_int not u_long as
* u_long is architecture dependent (e.g. 8 bytes on 64 bit). */
*cpp += sizeof(u_int);
dlen = _getshort(*cpp);
ptr->dlen = dlen;
*cpp += sizeof(u_short);
rd = &ptr->rdata;
/*
* Handle RR-specifics
*
* (No indication of failures here is
* passed back to the calling procedure)
*/
switch(ptr->type) {
case T_A: /* Address */
switch (ptr->rclass) {
case C_IN:
memcpy((void *)&rd->address, (void *)*cpp, sizeof(struct in_addr));
*cpp += dlen;
break;
default:
/* Can't really handle this - just skip it */
*cpp += dlen;
}
break;
case T_NS: /* Name Server */
case T_MD: /* Mail Destination (OBS) */
case T_MF: /* Mail Forwarder (OBS) */
case T_CNAME: /* Canonical Name */
rd->string = expand_cdname(cpp, msg);
break;
case T_SOA: /* Start of Authority */
rd->soa.mname = expand_cdname(cpp, msg);
rd->soa.rname = expand_cdname(cpp, msg);
rd->soa.serial = _getlong(*cpp);
*cpp += sizeof(u_long);
rd->soa.refresh = _getlong(*cpp);
*cpp += sizeof(u_long);
rd->soa.retry = _getlong(*cpp);
*cpp += sizeof(u_long);
rd->soa.expire = _getlong(*cpp);
*cpp += sizeof(u_long);
rd->soa.minimum = _getlong(*cpp);
*cpp += sizeof(u_long);
break;
case T_MB: /* Mail Box */
case T_MG: /* Mail Group */
case T_MR: /* Mail Rename */
rd->string = expand_cdname(cpp, msg);
break;
/* Following modification taken from VxWorks --GAT */
/* 01b,29apr97,jag Changed T_NULL to T_NULL_RR to fix conflict with loadCoffLib.h */
case T_NULL_RR: /* Null RR */
if ((rd->null.anything = (char *)malloc(dlen)) != NULL )
memcpy((void *)rd->null.anything, (void *)*cpp, dlen);
rd->null.length = dlen;
*cpp += dlen;
break;
case T_WKS: /* Well Known Services */
memcpy((void *)&rd->wks.address, (void *)*cpp, sizeof(struct in_addr));
*cpp += sizeof(struct in_addr);
rd->wks.protocol = **cpp;
(*cpp)++;
rd->wks.maplength = dlen-(sizeof(struct in_addr) +1);
if ((rd->wks.bitmap = (char *)malloc(rd->wks.maplength)) != NULL )
memcpy((void *)rd->wks.bitmap, (void *)*cpp, rd->wks.maplength);
*cpp += rd->wks.maplength;
break;
case T_PTR: /* Domain Name Pointer */
rd->string = expand_cdname(cpp, msg);
break;
case T_HINFO: /* Host Info */
if (( rd->hinfo.cpu = expand_charstring(cpp, msg)) == NULL ) {
cpp += dlen;
break;
}
if (( rd->hinfo.os = expand_charstring(cpp, msg)) == NULL ) {
cpp -= (strlen(rd->hinfo.cpu) +1);
cpp += dlen;
break;
}
break;
case T_MINFO: /* Mailbox Info */
rd->minfo.rmailbx = expand_cdname(cpp, msg);
rd->minfo.emailbx = expand_cdname(cpp, msg);
break;
case T_MX: /* Mail Exchanger */
rd->mx.preference = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->mx.exchange = expand_cdname(cpp, msg);
break;
case T_SRV: /* Service location */
rd->srv.priority = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->srv.weight = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->srv.port = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->srv.target = expand_cdname(cpp, msg);
break;
case T_NAPTR: /* Naming authority pointer */
{
// This is copied from the other cases, but I think that
// all cases should be setting *cpp += dlen, not
// cpp += dlen.
char **cpp_end = cpp + dlen;
rd->naptr.order = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->naptr.preference = _getshort(*cpp);
*cpp += sizeof(u_short);
if (( rd->naptr.flags = expand_charstring(cpp, msg)) == NULL ) {
cpp = cpp_end;
break;
}
if (( rd->naptr.services = expand_charstring(cpp, msg)) == NULL ) {
cpp = cpp_end;
break;
}
if (( rd->naptr.regexp = expand_charstring(cpp, msg)) == NULL ) {
cpp = cpp_end;
break;
}
rd->naptr.replacement = expand_cdname(cpp, msg);
}
break;
case T_TXT: /* Text string */
rd->txt.len = **cpp;
rd->txt.next = NULL;
if ((rd->txt.text = expand_charstring(cpp, msg)) == NULL ) {
cpp += dlen;
break;
}
/*
* Multiple strings
* add onto a linked list
*/
if ( rd->txt.len+1 < dlen ) {
struct s_TXT *txtp;
char **cpp2;
int n;
n = rd->txt.len+1;
txtp = &(rd->txt);
cpp2 = cpp;
while ( n < dlen ) {
if ((txtp->next = (struct s_TXT *)malloc(sizeof(struct s_TXT))) == NULL ) {
cpp += (dlen - rd->txt.len);
break;
}
txtp = txtp->next;
txtp->len = **cpp2;
n += txtp->len+1;
txtp->next = NULL;
if ((txtp->text = expand_charstring(cpp2, msg)) == NULL ) {
cpp += (dlen - rd->txt.len);
break;
}
}
}
break;
/*
* RFC 1183 Additional types
*/
case T_AFSDB: /* AFS Server */
rd->afsdb.subtype = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->afsdb.hostname = expand_cdname(cpp, msg);
break;
case T_RP: /* Responsible Person */
rd->rp.mbox_dname = expand_cdname(cpp, msg);
rd->rp.txt_dname = expand_cdname(cpp, msg);
break;
case T_X25: /* X25 Address */
rd->string = expand_charstring(cpp, msg);
break;
case T_ISDN: /* ISDN Address */
if ( **cpp == dlen ) {
rd->isdn.address = expand_charstring(cpp, msg);
rd->isdn.sa = NULL;
}
else {
rd->isdn.address = expand_charstring(cpp, msg);
rd->isdn.sa = expand_charstring(cpp, msg);
}
break;
case T_RT: /* Route Through */
rd->rt.preference = _getshort(*cpp);
*cpp += sizeof(u_short);
rd->rt.int_host = expand_cdname(cpp, msg);
break;
/*
* Additional Non-standard types
*/
case T_UINFO: /* User (finger) info */
if ((rd->string = (char *)malloc(dlen+1)) != NULL ) {
memcpy((void *)rd->string, (void *)*cpp, dlen);
rd->string[dlen] = '\0';
}
*cpp += dlen;
break;
case T_UID: /* User ID */
case T_GID: /* Group ID */
rd->number = _getlong(*cpp);
*cpp += sizeof(u_long);
break;
case T_UNSPEC: /* Unspecified info */
default: /* Unrecognised */
if ((rd->string = (char *)malloc(dlen+1)) != NULL )
memcpy((void *)rd->string, (void *)*cpp, dlen);
*cpp += dlen;
break;
}
return(ptr);
}
