resolvlibdoc.c

vxworks source code, used for develop vxworks system.

/*******************************************************************************
*
* resolvParamsGet - get the parameters which control the resolver library
*
* This routine copies the resolver parameters to the RESOLV_PARAMS_S
* structure referenced in the <pResolvParms> parameter.  The RESOLV_PARAMS_S
* structure is defined in resolvLib.h as follows: 
* .CS
*     typedef struct
*        {
*        char   queryOrder;
*        char   domainName [MAXDNAME];
*        char   nameServersAddr [MAXNS][MAXIPADDRLEN];
*        } RESOLV_PARAMS_S;
* .CE
* Typically, you call this function just before calling resolvParamsSet().
* The resolvParamsGet() call populates the RESOLV_PARAMS_S structure. 
* You can then modify the default values just before calling 
* resolvParamsSet().  
*
* RETURNS: N/A
*
* SEE ALSO:
* resolvGetHostByName(), resolvGetHostByAddr(), resolvDNExpand(),
* resolvDNComp(), resolvSend(), resolvParamsSet(), resolvInit(),
* resolvMkQuery(), resolvQuery()
*/

void resolvParamsGet 
    (
    RESOLV_PARAMS_S *     pResolvParams  /* ptr to resolver parameter struct */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvHostLibGetByName - query the DNS server in behalf of hostGetByName
*
* When the resolver library is installed, the routine hostGetByName() in the 
* hostLib library invokes this routine.  When the host name is not found by
* hostGetByName in the static host table.  This feature allows existing 
* applications to take advantage of the resolver without any changes.
*
* NOMANUAL
*
* ERRNO:
*  S_resolvLib_TRY_AGAIN
*  S_resolvLib_HOST_NOT_FOUND
*  S_resolvLib_NO_DATA
*  S_resolvLib_NO_RECOVERY
*
* RETURNS: IP address of host, or ERROR if the host was not found.
*/

LOCAL int resolvHostLibGetByName 
    (
    char * pHostName       /* Pointer to host name */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvHostLibGetByAddr - query the DNS server in behalf of hostGetByAddr()
*
* When the resolver library is installed the routine hostGetByAddr() in the 
* hostLib library invokes this routine.  When the IP address is not found by
* hostGetByAddr() in the static host table.  This feature allows existing 
* applications to take advantage of the resolver without any changes.  The
* <addr> paramter specifies the IP address and <pHostName> points to the
* official name of the host when the query is successful.
*
* NOMANUAL
*
* ERRNO:
*  S_resolvLib_TRY_AGAIN
*  S_resolvLib_HOST_NOT_FOUND
*  S_resolvLib_NO_DATA
*  S_resolvLib_NO_RECOVERY
*
* RETURNS: OK, or ERROR if the host name was not found.
*/

LOCAL STATUS resolvHostLibGetByAddr
    (
    int   addr,			/* IP address of requested host name */
    char * pHostName		/* host name output by this routine */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvDNExpand - expand a DNS compressed name from a DNS packet
*
* This functions expands a compressed DNS name from a DNS packet.  The <msg>
* parameter points to that start of the DNS packet.  The <eomorig> parameter
* points to the last location of the DNS packet plus 1.  The <comp_dn> 
* parameter points to the compress domain name, and <exp_dn> parameter 
* expects a pointer to a buffer.  Upon function completion, this buffer 
* contains the expanded domain name.  Use the <length> parameter to pass in
* the size of the buffer referenced by the <exp_dn> parameter.  
*
* RETURNS: The length of the expanded domain name, or ERROR on failure.
*
* SEE ALSO:
* resolvGetHostByName(), resolvGetHostByAddr(), resolvInit(),
* resolvDNComp(), resolvSend(), resolvParamsSet(), resolvParamsGet(),
* resolvMkQuery(), resolvQuery()
*/

int resolvDNExpand 
    (
    const u_char * msg,     /* ptr to the start of the DNS packet */
    const u_char * eomorig, /* ptr to the last location +1 of the DNS packet */
    const u_char * comp_dn, /* ptr to the compressed domain name */
          u_char * exp_dn,  /* ptr to where the expanded DN is output */
          int      length   /* length of the buffer pointed by <expd_dn> */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvDNComp - compress a DNS name in a DNS packet
*
* This routine takes the expanded domain name referenced in the <exp_dn> 
* parameter, compresses it, and stores the compressed name in the location
* pointed to by the <comp_dn> parameter.  The <length> parameter passes in 
* the length of the buffer starting at <comp_dn>.  The <dnptrs> parameter 
* is a pointer to a list of pointers to previously compressed names.  The 
* <lastdnptr> parameter points to the last entry in the <dnptrs> array.
*
* RETURNS: The size of the compressed name, or ERROR.
*
* SEE ALSO:
* resolvGetHostByName(), resolvGetHostByAddr(), resolvDNExpand(),
* resolvInit(), resolvSend(), resolvParamsSet(), resolvParamsGet(),
* resolvMkQuery(), resolvQuery()
*/

int resolvDNComp 
    (
    const u_char *  exp_dn,   /* ptr to the expanded domain name */
          u_char *  comp_dn,  /* ptr to where to output the compressed name */  
          int       length,   /* length of the buffer pointed by <comp_dn> */
          u_char ** dnptrs,   /* ptr to a ptr list of compressed names */ 
          u_char ** lastdnptr /* ptr to the last entry pointed by <dnptrs> */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvQuery - construct a query, send it, wait for a response
*
* This routine constructs a query for the domain specified in the <name> 
* parameter.  The <class> parameter specifies the class of the query. 
* The <type> parameter specifies the type of query. The routine then sends
* the query to the DNS server.  When the server responds, the response is 
* validated and copied to the buffer you supplied in the <answer> parameter.
* Use the <anslen> parameter to pass in the size of the buffer referenced
* in <answer>.
*
* RETURNS: The length of the response or ERROR.
*
* ERRNO:
*  S_resolvLib_TRY_AGAIN
*  S_resolvLib_HOST_NOT_FOUND
*  S_resolvLib_NO_DATA
*  S_resolvLib_NO_RECOVERY
*
* SEE ALSO:
* resolvGetHostByName(), resolvGetHostByAddr(), resolvDNExpand(),
* resolvDNComp(), resolvInit(), resolvParamsSet(), resolvParamsGet(),
* resolvMkQuery()
*/

int resolvQuery 
    (
    char   *name,       /* domain name */
    int    class,       /* query class for IP is C_IN */
    int    type,        /* type is T_A, T_PTR, ... */
    u_char *answer,     /* buffer to put answer */
    int    anslen       /* length of answer buffer */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvMkQuery - create all types of DNS queries
*
* This routine uses the input parameters to create a domain name query.
* You can set the <op> parameter to QUERY or IQUERY.  Specify the domain 
* name in <dname>, the class in <class>, the query type in <type>.  Valid
* values for type include T_A, T_PTR, and so on.  Use <data> to add Resource 
* Record data to the query.  Use <datalen> to pass in the length of the 
* data buffer.  Set <newrr_in> to NULL.  This parameter is reserved for 
* future use.  The <buf> parameter expects a pointer to the output buffer 
* for the constructed query.  Use <buflen> to pass in the length of the 
* buffer referenced in <buf>.
*
* RETURNS: The length of the constructed query or ERROR.
*
* SEE ALSO:
* resolvGetHostByName(), resolvGetHostByAddr(), resolvDNExpand(),
* resolvDNComp(), resolvSend(), resolvParamsSet(), resolvParamsGet(),
* resolvInit(), resolvQuery()
*/

int resolvMkQuery 
    (
          int     op,	       /* set to desire query QUERY or IQUERY */
    const char *  dname,       /* domain name to be use in the query */
    int           class,       /* query class for IP is C_IN */
    int           type,        /* type is T_A, T_PTR, ... */
    const char *  data,        /* resource Record (RR) data */
    int           datalen,     /* length of the RR */
    const char *  newrr_in,    /* not used always set to NULL */
          char *  buf,         /* out of the constructed query */
          int     buflen       /* length of the buffer for the query */
    )
    {
    ...
    }

/*******************************************************************************
*
* resolvSend - send a pre-formatted query and return the answer
*
* This routine takes a pre-formatted DNS query and sends it to the domain
* server.  Use <buf> to pass in a pointer to the query.  Use <buflen> to 
* pass in the size of the buffer referenced in <buf>.  The <answer> parameter
* expects a pointer to a buffer into which this routine can write the 
* answer retrieved from the server.  Use <anslen> to pass in the size of
* the buffer you have provided in <anslen>.
*
* RETURNS: The length of the response or ERROR.
*
* ERRNO:
*  S_resolvLib_TRY_AGAIN
*  ECONNREFUSE
*  ETIMEDOU
*
* SEE ALSO:
* resolvGetHostByName(), resolvGetHostByAddr(), resolvDNExpand(),
* resolvDNComp(), resolvInit(), resolvParamsSet(), resolvParamsGet(),
* resolvMkQuery(), resolvQuery()
*/

int resolvSend 
    (
    const char * buf,		/* pre-formatted query */
          int    buflen,	/* length of query */
          char * answer,	/* buffer for answer */
          int    anslen		/* length of answer */
    )
    {
    ...
    }