+/* Creation of DNS query packets.
+ Copyright (C) 1995-2019 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. All rights reserved.
* SOFTWARE.
*/
-#if defined(LIBC_SCCS) && !defined(lint)
-static const char sccsid[] = "@(#)res_mkquery.c 8.1 (Berkeley) 6/4/93";
-static const char rcsid[] = "$BINDId: res_mkquery.c,v 8.12 1999/10/13 16:39:40 vixie Exp $";
-#endif /* LIBC_SCCS and not lint */
-
+#include <stdint.h>
#include <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <netdb.h>
-#include <resolv.h>
-#include <stdio.h>
+#include <resolv/resolv-internal.h>
+#include <resolv/resolv_context.h>
#include <string.h>
+#include <sys/time.h>
+#include <shlib-compat.h>
+#include <random-bits.h>
-/* Options. Leave them on. */
-/* #define DEBUG */
+int
+__res_context_mkquery (struct resolv_context *ctx, int op, const char *dname,
+ int class, int type, const unsigned char *data,
+ unsigned char *buf, int buflen)
+{
+ HEADER *hp;
+ unsigned char *cp;
+ int n;
+ unsigned char *dnptrs[20], **dpp, **lastdnptr;
-#ifdef _LIBC
-# include <hp-timing.h>
-# if HP_TIMING_AVAIL
-# define RANDOM_BITS(Var) { uint64_t v64; HP_TIMING_NOW (v64); Var = v64; }
-# endif
-#endif
+ if (class < 0 || class > 65535 || type < 0 || type > 65535)
+ return -1;
-/*
- * Form all types of queries.
- * Returns the size of the result or -1.
- */
+ /* Initialize header fields. */
+ if ((buf == NULL) || (buflen < HFIXEDSZ))
+ return -1;
+ memset (buf, 0, HFIXEDSZ);
+ hp = (HEADER *) buf;
+ /* We randomize the IDs every time. The old code just incremented
+ by one after the initial randomization which still predictable if
+ the application does multiple requests. */
+ hp->id = random_bits ();
+ hp->opcode = op;
+ hp->rd = (ctx->resp->options & RES_RECURSE) != 0;
+ hp->rcode = NOERROR;
+ cp = buf + HFIXEDSZ;
+ buflen -= HFIXEDSZ;
+ dpp = dnptrs;
+ *dpp++ = buf;
+ *dpp++ = NULL;
+ lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
+
+ /* Perform opcode specific processing. */
+ switch (op)
+ {
+ case NS_NOTIFY_OP:
+ if ((buflen -= QFIXEDSZ + (data == NULL ? 0 : RRFIXEDSZ)) < 0)
+ return -1;
+ goto compose;
+
+ case QUERY:
+ if ((buflen -= QFIXEDSZ) < 0)
+ return -1;
+ compose:
+ n = ns_name_compress (dname, cp, buflen,
+ (const unsigned char **) dnptrs,
+ (const unsigned char **) lastdnptr);
+ if (n < 0)
+ return -1;
+ cp += n;
+ buflen -= n;
+ NS_PUT16 (type, cp);
+ NS_PUT16 (class, cp);
+ hp->qdcount = htons (1);
+ if (op == QUERY || data == NULL)
+ break;
+
+ /* Make an additional record for completion domain. */
+ n = ns_name_compress ((char *)data, cp, buflen,
+ (const unsigned char **) dnptrs,
+ (const unsigned char **) lastdnptr);
+ if (__glibc_unlikely (n < 0))
+ return -1;
+ cp += n;
+ buflen -= n;
+ NS_PUT16 (T_NULL, cp);
+ NS_PUT16 (class, cp);
+ NS_PUT32 (0, cp);
+ NS_PUT16 (0, cp);
+ hp->arcount = htons (1);
+ break;
+
+ default:
+ return -1;
+ }
+ return cp - buf;
+}
+
+/* Common part of res_nmkquery and res_mkquery. */
+static int
+context_mkquery_common (struct resolv_context *ctx,
+ int op, const char *dname, int class, int type,
+ const unsigned char *data,
+ unsigned char *buf, int buflen)
+{
+ if (ctx == NULL)
+ return -1;
+ int result = __res_context_mkquery
+ (ctx, op, dname, class, type, data, buf, buflen);
+ if (result >= 2)
+ memcpy (&ctx->resp->id, buf, 2);
+ __resolv_context_put (ctx);
+ return result;
+}
+
+/* Form all types of queries. Returns the size of the result or -1 on
+ error.
+
+ STATP points to an initialized resolver state. OP is the opcode of
+ the query. DNAME is the domain. CLASS and TYPE are the DNS query
+ class and type. DATA can be NULL; otherwise, it is a pointer to a
+ domain name which is included in the generated packet (if op ==
+ NS_NOTIFY_OP). BUF must point to the out buffer of BUFLEN bytes.
+
+ DATALEN and NEWRR_IN are currently ignored. */
int
-res_nmkquery(res_state statp,
- int op, /* opcode of query */
- const char *dname, /* domain name */
- int class, int type, /* class and type of query */
- const u_char *data, /* resource record data */
- int datalen, /* length of data */
- const u_char *newrr_in, /* new rr for modify or append */
- u_char *buf, /* buffer to put query */
- int buflen) /* size of buffer */
+res_nmkquery (res_state statp, int op, const char *dname,
+ int class, int type,
+ const unsigned char *data, int datalen,
+ const unsigned char *newrr_in,
+ unsigned char *buf, int buflen)
{
- register HEADER *hp;
- register u_char *cp;
- register int n;
- u_char *dnptrs[20], **dpp, **lastdnptr;
-
-#ifdef DEBUG
- if (statp->options & RES_DEBUG)
- printf(";; res_nmkquery(%s, %s, %s, %s)\n",
- _res_opcodes[op], dname, p_class(class), p_type(type));
-#endif
- /*
- * Initialize header fields.
- */
- if ((buf == NULL) || (buflen < HFIXEDSZ))
- return (-1);
- memset(buf, 0, HFIXEDSZ);
- hp = (HEADER *) buf;
- /* We randomize the IDs every time. The old code just
- incremented by one after the initial randomization which
- still predictable if the application does multiple
- requests. */
- int randombits;
- do
- {
-#ifdef RANDOM_BITS
- RANDOM_BITS (randombits);
-#else
- struct timeval tv;
- __gettimeofday (&tv, NULL);
- randombits = (tv.tv_sec << 8) ^ tv.tv_usec;
-#endif
- }
- while ((randombits & 0xffff) == 0);
- statp->id = (statp->id + randombits) & 0xffff;
- hp->id = statp->id;
- hp->opcode = op;
- hp->rd = (statp->options & RES_RECURSE) != 0;
- hp->rcode = NOERROR;
- cp = buf + HFIXEDSZ;
- buflen -= HFIXEDSZ;
- dpp = dnptrs;
- *dpp++ = buf;
- *dpp++ = NULL;
- lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
- /*
- * perform opcode specific processing
- */
- switch (op) {
- case NS_NOTIFY_OP:
- if ((buflen -= QFIXEDSZ + (data == NULL ? 0 : RRFIXEDSZ)) < 0)
- return (-1);
- goto compose;
-
- case QUERY:
- if ((buflen -= QFIXEDSZ) < 0)
- return (-1);
- compose:
- if ((n = dn_comp(dname, cp, buflen, dnptrs, lastdnptr)) < 0)
- return (-1);
- cp += n;
- buflen -= n;
- NS_PUT16 (type, cp);
- NS_PUT16 (class, cp);
- hp->qdcount = htons(1);
- if (op == QUERY || data == NULL)
- break;
- /*
- * Make an additional record for completion domain.
- */
- n = dn_comp((char *)data, cp, buflen, dnptrs, lastdnptr);
- if (__builtin_expect (n < 0, 0))
- return (-1);
- cp += n;
- buflen -= n;
- NS_PUT16 (T_NULL, cp);
- NS_PUT16 (class, cp);
- NS_PUT32 (0, cp);
- NS_PUT16 (0, cp);
- hp->arcount = htons(1);
- break;
-
- case IQUERY:
- /*
- * Initialize answer section
- */
- if (__builtin_expect (buflen < 1 + RRFIXEDSZ + datalen, 0))
- return (-1);
- *cp++ = '\0'; /* no domain name */
- NS_PUT16 (type, cp);
- NS_PUT16 (class, cp);
- NS_PUT32 (0, cp);
- NS_PUT16 (datalen, cp);
- if (datalen) {
- memcpy(cp, data, datalen);
- cp += datalen;
- }
- hp->ancount = htons(1);
- break;
-
- default:
- return (-1);
- }
- return (cp - buf);
+ return context_mkquery_common
+ (__resolv_context_get_override (statp),
+ op, dname, class, type, data, buf, buflen);
+}
+
+int
+res_mkquery (int op, const char *dname, int class, int type,
+ const unsigned char *data, int datalen,
+ const unsigned char *newrr_in,
+ unsigned char *buf, int buflen)
+{
+ return context_mkquery_common
+ (__resolv_context_get_preinit (),
+ op, dname, class, type, data, buf, buflen);
}
-libresolv_hidden_def (res_nmkquery)
+
+/* Create an OPT resource record. Return the length of the final
+ packet, or -1 on error.
+
+ STATP must be an initialized resolver state. N0 is the current
+ number of bytes of the packet (already written to BUF by the
+ aller). BUF is the packet being constructed. The array it
+ pointers to must be BUFLEN bytes long. ANSLEN is the advertised
+ EDNS buffer size (to be included in the OPT resource record). */
+int
+__res_nopt (struct resolv_context *ctx,
+ int n0, unsigned char *buf, int buflen, int anslen)
+{
+ uint16_t flags = 0;
+ HEADER *hp = (HEADER *) buf;
+ unsigned char *cp = buf + n0;
+ unsigned char *ep = buf + buflen;
+
+ if ((ep - cp) < 1 + RRFIXEDSZ)
+ return -1;
+
+ /* Add the root label. */
+ *cp++ = 0;
+
+ NS_PUT16 (T_OPT, cp); /* Record type. */
+
+ /* Lowering the advertised buffer size based on the actual
+ answer buffer size is desirable because the server will
+ minimize the reply to fit into the UDP packet (and A
+ non-minimal response might not fit the buffer).
+
+ The RESOLV_EDNS_BUFFER_SIZE limit could still result in TCP
+ fallback and a non-minimal response which has to be
+ hard-truncated in the stub resolver, but this is price to
+ pay for avoiding fragmentation. (This issue does not
+ affect the nss_dns functions because they use the stub
+ resolver in such a way that it allocates a properly sized
+ response buffer.) */
+ {
+ uint16_t buffer_size;
+ if (anslen < 512)
+ buffer_size = 512;
+ else if (anslen > RESOLV_EDNS_BUFFER_SIZE)
+ buffer_size = RESOLV_EDNS_BUFFER_SIZE;
+ else
+ buffer_size = anslen;
+ NS_PUT16 (buffer_size, cp);
+ }
+
+ *cp++ = NOERROR; /* Extended RCODE. */
+ *cp++ = 0; /* EDNS version. */
+
+ if (ctx->resp->options & RES_USE_DNSSEC)
+ flags |= NS_OPT_DNSSEC_OK;
+
+ NS_PUT16 (flags, cp);
+ NS_PUT16 (0, cp); /* RDATA length (no options are preent). */
+ hp->arcount = htons (ntohs (hp->arcount) + 1);
+
+ return cp - buf;
+}
+
+#if SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2)
+# undef res_mkquery
+weak_alias (__res_mkquery, res_mkquery);
+#endif
projects / thirdparty / glibc.git / blobdiff