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<!-- Copyright (C) 2003 Red Hat, Inc. --><!-- This material may be distributed only subject to the terms --><!-- and conditions set forth in the Open Publication License, v1.0 --><!-- or later (the latest version is presently available at --><!-- http://www.opencontent.org/openpub/). --><!-- Distribution of the work or derivative of the work in any --><!-- standard (paper) book form is prohibited unless prior --><!-- permission is obtained from the copyright holder. --><HTML><HEAD><TITLE>getrrsetbyname</TITLE><meta name="MSSmartTagsPreventParsing" content="TRUE"><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+"><LINKREL="HOME"TITLE="eCos Reference Manual"HREF="ecos-ref.html"><LINKREL="UP"TITLE="TCP/IP Library Reference"HREF="tcpip-library-reference.html"><LINKREL="PREVIOUS"TITLE="getprotoent"HREF="net-common-tcpip-manpages-getprotoent.html"><LINKREL="NEXT"TITLE="getservent"HREF="net-common-tcpip-manpages-getservent.html"></HEAD><BODYCLASS="SECT1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">eCos Reference Manual</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="net-common-tcpip-manpages-getprotoent.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">Chapter 38. TCP/IP Library Reference</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="net-common-tcpip-manpages-getservent.html"ACCESSKEY="N">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="SECT1"><H1CLASS="SECT1"><ANAME="NET-COMMON-TCPIP-MANPAGES-GETRRSETBYNAME">getrrsetbyname</H1><TABLEBORDER="5"BGCOLOR="#E0E0F0"WIDTH="70%"><TR><TD><PRECLASS="SCREEN">GETRRSETBYNAME(3) System Library Functions Manual GETRRSETBYNAME(3)NAME getrrsetbyname - retrieve DNS recordsSYNOPSIS #include <netdb.h> int getrrsetbyname(const char *hostname, unsigned int rdclass, unsigned int rdtype, unsigned int flags, struct rrsetinfo **res); int freerrset(struct rrsetinfo **rrset);DESCRIPTION getrrsetbyname() gets a set of resource records associated with a hostname, class and type. hostname is a pointer a to null-terminated string. The flags field is currently unused and must be zero. After a successful call to getrrsetbyname(), *res is a pointer to an rrsetinfo structure, containing a list of one or more rdatainfo struc- tures containing resource records and potentially another list of rdatainfo structures containing SIG resource records associated with those records. The members rri_rdclass and rri_rdtype are copied from the parameters. rri_ttl and rri_name are properties of the obtained rrset. The resource records contained in rri_rdatas and rri_sigs are in uncompressed DNS wire format. Properties of the rdataset are represented in the rri_flags bitfield. If the RRSET_VALIDATED bit is set, the data has been DNSSEC validated and the signatures verified. The following structures are used: struct rdatainfo { unsigned int rdi_length; /* length of data */ unsigned char *rdi_data; /* record data */ }; struct rrsetinfo { unsigned int rri_flags; /* RRSET_VALIDATED ... */ unsigned int rri_rdclass; /* class number */ unsigned int rri_rdtype; /* RR type number */ unsigned int rri_ttl; /* time to live */ unsigned int rri_nrdatas; /* size of rdatas array */ unsigned int rri_nsigs; /* size of sigs array */ char *rri_name; /* canonical name */ struct rdatainfo *rri_rdatas; /* individual records */ struct rdatainfo *rri_sigs; /* individual signatures */ }; All of the information returned by getrrsetbyname() is dynamically allo- cated: the rrsetinfo and rdatainfo structures, and the canonical host name strings pointed to by the rrsetinfostructure. Memory allocated for the dynamically allocated structures created by a successful call to getrrsetbyname() is released by freerrset(). rrset is a pointer to a struct rrset created by a call to getrrsetbyname(). If the EDNS0 option is activated in resolv.conf(3), getrrsetbyname() will request DNSSEC authentication using the EDNS0 DNSSEC OK (DO) bit.RETURN VALUES getrrsetbyname() returns zero on success, and one of the following error codes if an error occurred: ERRSET_NONAME the name does not exist ERRSET_NODATA the name exists, but does not have data of the desired type ERRSET_NOMEMORY memory could not be allocated ERRSET_INVAL a parameter is invalid ERRSET_FAIL other failureSEE ALSO resolver(3), resolv.conf(5), named(8)AUTHORS Jakob Schlyter <jakob@openbsd.org>HISTORY getrrsetbyname() first appeared in OpenBSD 3.0. The API first appeared in ISC BIND version 9.BUGS The data in *rdi_data should be returned in uncompressed wire format. Currently, the data is in compressed format and the caller can't uncom- press since it doesn't have the full message.CAVEATS The RRSET_VALIDATED flag in rri_flags is set if the AD (autenticated data) bit in the DNS answer is set. This flag should not be trusted unless the transport between the nameserver and the resolver is secure (e.g. IPsec, trusted network, loopback communication).BSD Oct 18, 2000 BSD </PRE></TD></TR></TABLE></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLESUMMARY="Footer navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="net-common-tcpip-manpages-getprotoent.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="ecos-ref.html"ACCESSKEY="H">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="net-common-tcpip-manpages-getservent.html"ACCESSKEY="N">Next</A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">getprotoent</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="tcpip-library-reference.html"ACCESSKEY="U">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">getservent</TD></TR></TABLE></DIV></BODY></HTML>⌨️ 快捷键说明
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