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author | hpopescu@ixiacom.com <hpopescu@ixiacom.com> | 2012-08-10 12:06:09 +0300 |
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committer | Daniel Stenberg <daniel@haxx.se> | 2012-08-17 00:54:47 +0200 |
commit | 90364defb038d5d6b97acf9df9ed152d2393a863 (patch) | |
tree | 82ea71d7a7718652727fed628849a247c464728b /ares_mkquery.c | |
parent | e447bc5c603a139852fd74d9930c1293535ea749 (diff) | |
download | c-ares-90364defb038d5d6b97acf9df9ed152d2393a863.tar.gz c-ares-90364defb038d5d6b97acf9df9ed152d2393a863.tar.bz2 c-ares-90364defb038d5d6b97acf9df9ed152d2393a863.zip |
Added new feature (rfc2671)
Diffstat (limited to 'ares_mkquery.c')
-rw-r--r-- | ares_mkquery.c | 173 |
1 files changed, 1 insertions, 172 deletions
diff --git a/ares_mkquery.c b/ares_mkquery.c index e33f13f..5aea914 100644 --- a/ares_mkquery.c +++ b/ares_mkquery.c @@ -15,181 +15,10 @@ */ #include "ares_setup.h" - -#ifdef HAVE_SYS_SOCKET_H -# include <sys/socket.h> -#endif -#ifdef HAVE_NETINET_IN_H -# include <netinet/in.h> -#endif -#ifdef HAVE_ARPA_NAMESER_H -# include <arpa/nameser.h> -#else -# include "nameser.h" -#endif -#ifdef HAVE_ARPA_NAMESER_COMPAT_H -# include <arpa/nameser_compat.h> -#endif - -#include <stdlib.h> -#include <string.h> #include "ares.h" -#include "ares_dns.h" -#include "ares_private.h" - -/* Header format, from RFC 1035: - * 1 1 1 1 1 1 - * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | ID | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * |QR| Opcode |AA|TC|RD|RA| Z | RCODE | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | QDCOUNT | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | ANCOUNT | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | NSCOUNT | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | ARCOUNT | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * - * AA, TC, RA, and RCODE are only set in responses. Brief description - * of the remaining fields: - * ID Identifier to match responses with queries - * QR Query (0) or response (1) - * Opcode For our purposes, always QUERY - * RD Recursion desired - * Z Reserved (zero) - * QDCOUNT Number of queries - * ANCOUNT Number of answers - * NSCOUNT Number of name server records - * ARCOUNT Number of additional records - * - * Question format, from RFC 1035: - * 1 1 1 1 1 1 - * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | | - * / QNAME / - * / / - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | QTYPE | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * | QCLASS | - * +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ - * - * The query name is encoded as a series of labels, each represented - * as a one-byte length (maximum 63) followed by the text of the - * label. The list is terminated by a label of length zero (which can - * be thought of as the root domain). - */ int ares_mkquery(const char *name, int dnsclass, int type, unsigned short id, int rd, unsigned char **buf, int *buflen) { - int len; - unsigned char *q; - const char *p; - - /* Set our results early, in case we bail out early with an error. */ - *buflen = 0; - *buf = NULL; - - /* Compute the length of the encoded name so we can check buflen. - * Start counting at 1 for the zero-length label at the end. */ - len = 1; - for (p = name; *p; p++) - { - if (*p == '\\' && *(p + 1) != 0) - p++; - len++; - } - /* If there are n periods in the name, there are n + 1 labels, and - * thus n + 1 length fields, unless the name is empty or ends with a - * period. So add 1 unless name is empty or ends with a period. - */ - if (*name && *(p - 1) != '.') - len++; - - /* Immediately reject names that are longer than the maximum of 255 - * bytes that's specified in RFC 1035 ("To simplify implementations, - * the total length of a domain name (i.e., label octets and label - * length octets) is restricted to 255 octets or less."). We aren't - * doing this just to be a stickler about RFCs. For names that are - * too long, 'dnscache' closes its TCP connection to us immediately - * (when using TCP) and ignores the request when using UDP, and - * BIND's named returns ServFail (TCP or UDP). Sending a request - * that we know will cause 'dnscache' to close the TCP connection is - * painful, since that makes any other outstanding requests on that - * connection fail. And sending a UDP request that we know - * 'dnscache' will ignore is bad because resources will be tied up - * until we time-out the request. - */ - if (len > MAXCDNAME) - return ARES_EBADNAME; - - *buflen = len + HFIXEDSZ + QFIXEDSZ; - *buf = malloc(*buflen); - if (!*buf) - return ARES_ENOMEM; - - /* Set up the header. */ - q = *buf; - memset(q, 0, HFIXEDSZ); - DNS_HEADER_SET_QID(q, id); - DNS_HEADER_SET_OPCODE(q, QUERY); - if (rd) { - DNS_HEADER_SET_RD(q, 1); - } - else { - DNS_HEADER_SET_RD(q, 0); - } - DNS_HEADER_SET_QDCOUNT(q, 1); - - /* A name of "." is a screw case for the loop below, so adjust it. */ - if (strcmp(name, ".") == 0) - name++; - - /* Start writing out the name after the header. */ - q += HFIXEDSZ; - while (*name) - { - if (*name == '.') - return ARES_EBADNAME; - - /* Count the number of bytes in this label. */ - len = 0; - for (p = name; *p && *p != '.'; p++) - { - if (*p == '\\' && *(p + 1) != 0) - p++; - len++; - } - if (len > MAXLABEL) - return ARES_EBADNAME; - - /* Encode the length and copy the data. */ - *q++ = (unsigned char)len; - for (p = name; *p && *p != '.'; p++) - { - if (*p == '\\' && *(p + 1) != 0) - p++; - *q++ = *p; - } - - /* Go to the next label and repeat, unless we hit the end. */ - if (!*p) - break; - name = p + 1; - } - - /* Add the zero-length label at the end. */ - *q++ = 0; - - /* Finish off the question with the type and class. */ - DNS_QUESTION_SET_TYPE(q, type); - DNS_QUESTION_SET_CLASS(q, dnsclass); - - return ARES_SUCCESS; + return ares_create_query(name, dnsclass, type, id, rd, buf, buflen, 0); } |