Author: jerry Date: 2006-07-19 20:53:10 +0000 (Wed, 19 Jul 2006) New Revision: 17146
WebSVN: http://websvn.samba.org/cgi-bin/viewcvs.cgi?view=rev&root=samba&rev=17146 Log: Starting to cleanout my local tree some * add code to lookup NS records (in prep for later coe that does DNS updates as part of the net ads join) Modified: branches/SAMBA_3_0/source/include/ads_dns.h branches/SAMBA_3_0/source/libads/dns.c Changeset: Modified: branches/SAMBA_3_0/source/include/ads_dns.h =================================================================== --- branches/SAMBA_3_0/source/include/ads_dns.h 2006-07-19 19:40:46 UTC (rev 17145) +++ branches/SAMBA_3_0/source/include/ads_dns.h 2006-07-19 20:53:10 UTC (rev 17146) @@ -50,5 +50,12 @@ struct in_addr ip; }; +/* SRV records */ +struct dns_rr_ns { + const char *hostname; + struct in_addr ip; +}; + + #endif /* _ADS_DNS_H */ Modified: branches/SAMBA_3_0/source/libads/dns.c =================================================================== --- branches/SAMBA_3_0/source/libads/dns.c 2006-07-19 19:40:46 UTC (rev 17145) +++ branches/SAMBA_3_0/source/libads/dns.c 2006-07-19 20:53:10 UTC (rev 17146) @@ -46,6 +46,7 @@ # define T_A ns_t_a #endif # define T_SRV ns_t_srv +# define T_NS ns_t_ns #else # ifdef HFIXEDSZ # define NS_HFIXEDSZ HFIXEDSZ @@ -197,7 +198,47 @@ return True; } +/********************************************************************* +*********************************************************************/ +static BOOL ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end, + uint8 **ptr, struct dns_rr_ns *nsrec ) +{ + struct dns_rr rr; + uint8 *p; + pstring nsname; + int namelen; + + if ( !start || !end || !nsrec || !*ptr) + return -1; + + /* Parse the RR entry. Coming out of the this, ptr is at the beginning + of the next record */ + + if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) { + DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n")); + return False; + } + + if ( rr.type != T_NS ) { + DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n", rr.type)); + return False; + } + + p = rr.rdata; + + /* ame server hostname */ + + namelen = dn_expand( start, end, p, nsname, sizeof(nsname) ); + if ( namelen < 0 ) { + DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n")); + return False; + } + nsrec->hostname = talloc_strdup( ctx, nsname ); + + return True; +} + /********************************************************************* Sort SRV record list based on weight and priority. See RFC 2782. *********************************************************************/ @@ -230,27 +271,16 @@ } /********************************************************************* - Simple wrapper for a DNS SRV query + Simple wrapper for a DNS query *********************************************************************/ -NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs ) +static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type, + uint8 **buf, int *resp_length ) { uint8 *buffer = NULL; size_t buf_len; - int resp_len = NS_PACKETSZ; - struct dns_rr_srv *dcs = NULL; - int query_count, answer_count, auth_count, additional_count; - uint8 *p = buffer; - int rrnum; - int idx = 0; - - if ( !ctx || !name || !dclist ) { - return NT_STATUS_INVALID_PARAMETER; - } + int resp_len = NS_PACKETSZ; - /* Send the request. May have to loop several times in case - of large replies */ - do { if ( buffer ) TALLOC_FREE( buffer ); @@ -262,13 +292,47 @@ return NT_STATUS_NO_MEMORY; } - if ( (resp_len = res_query(name, C_IN, T_SRV, buffer, buf_len)) < 0 ) { + if ( (resp_len = res_query(name, C_IN, q_type, buffer, buf_len)) < 0 ) { DEBUG(1,("ads_dns_lookup_srv: Failed to resolve %s (%s)\n", name, strerror(errno))); TALLOC_FREE( buffer ); return NT_STATUS_UNSUCCESSFUL; } } while ( buf_len < resp_len && resp_len < MAX_DNS_PACKET_SIZE ); + + *buf = buffer; + *resp_length = resp_len; + return NT_STATUS_OK; +} + +/********************************************************************* + Simple wrapper for a DNS SRV query +*********************************************************************/ + +static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs ) +{ + uint8 *buffer = NULL; + int resp_len = 0; + struct dns_rr_srv *dcs = NULL; + int query_count, answer_count, auth_count, additional_count; + uint8 *p = buffer; + int rrnum; + int idx = 0; + NTSTATUS status; + + if ( !ctx || !name || !dclist ) { + return NT_STATUS_INVALID_PARAMETER; + } + + /* Send the request. May have to loop several times in case + of large replies */ + + status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len ); + if ( !NT_STATUS_IS_OK(status) ) { + DEBUG(0,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n", + nt_errstr(status))); + return status; + } p = buffer; /* For some insane reason, the ns_initparse() et. al. routines are only @@ -361,6 +425,125 @@ return NT_STATUS_OK; } +/********************************************************************* + Simple wrapper for a DNS NS query +*********************************************************************/ + +NTSTATUS ads_dns_lookup_ns( TALLOC_CTX *ctx, const char *dnsdomain, struct dns_rr_ns **nslist, int *numns ) +{ + uint8 *buffer = NULL; + int resp_len = 0; + struct dns_rr_ns *nsarray = NULL; + int query_count, answer_count, auth_count, additional_count; + uint8 *p; + int rrnum; + int idx = 0; + NTSTATUS status; + + if ( !ctx || !dnsdomain || !nslist ) { + return NT_STATUS_INVALID_PARAMETER; + } + + /* Send the request. May have to loop several times in case + of large replies */ + + status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len ); + if ( !NT_STATUS_IS_OK(status) ) { + DEBUG(0,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n", + nt_errstr(status))); + return status; + } + p = buffer; + + /* For some insane reason, the ns_initparse() et. al. routines are only + available in libresolv.a, and not the shared lib. Who knows why.... + So we have to parse the DNS reply ourselves */ + + /* Pull the answer RR's count from the header. Use the NMB ordering macros */ + + query_count = RSVAL( p, 4 ); + answer_count = RSVAL( p, 6 ); + auth_count = RSVAL( p, 8 ); + additional_count = RSVAL( p, 10 ); + + DEBUG(4,("ads_dns_lookup_ns: %d records returned in the answer section.\n", + answer_count)); + + if ( (nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns, answer_count)) == NULL ) { + DEBUG(0,("ads_dns_lookup_ns: talloc() failure for %d char*'s\n", + answer_count)); + return NT_STATUS_NO_MEMORY; + } + + /* now skip the header */ + + p += NS_HFIXEDSZ; + + /* parse the query section */ + + for ( rrnum=0; rrnum<query_count; rrnum++ ) { + struct dns_query q; + + if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) { + DEBUG(1,("ads_dns_lookup_ns: Failed to parse query record!\n")); + return NT_STATUS_UNSUCCESSFUL; + } + } + + /* now we are at the answer section */ + + for ( rrnum=0; rrnum<answer_count; rrnum++ ) { + if ( !ads_dns_parse_rr_ns( ctx, buffer, buffer+resp_len, &p, &nsarray[rrnum] ) ) { + DEBUG(1,("ads_dns_lookup_ns: Failed to parse answer record!\n")); + return NT_STATUS_UNSUCCESSFUL; + } + } + idx = rrnum; + + /* Parse the authority section */ + /* just skip these for now */ + + for ( rrnum=0; rrnum<auth_count; rrnum++ ) { + struct dns_rr rr; + + if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) { + DEBUG(1,("ads_dns_lookup_ns: Failed to parse authority record!\n")); + return NT_STATUS_UNSUCCESSFUL; + } + } + + /* Parse the additional records section */ + + for ( rrnum=0; rrnum<additional_count; rrnum++ ) { + struct dns_rr rr; + int i; + + if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) { + DEBUG(1,("ads_dns_lookup_ns: Failed to parse additional records section!\n")); + return NT_STATUS_UNSUCCESSFUL; + } + + /* only interested in A records as a shortcut for having to come + back later and lookup the name */ + + if ( (rr.type != T_A) || (rr.rdatalen != 4) ) + continue; + + for ( i=0; i<idx; i++ ) { + if ( strcmp( rr.hostname, nsarray[i].hostname ) == 0 ) { + uint8 *buf = (uint8*)&nsarray[i].ip.s_addr; + memcpy( buf, rr.rdata, 4 ); + } + } + } + + *nslist = nsarray; + *numns = idx; + + return NT_STATUS_OK; +} + + /******************************************************************** ********************************************************************/
