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* resolv/res_init.c (res_setoptions): Recognize edns0 option.
* resolv/res_mkquery.c: Define __res_nopt. * resolv/res_query.c (__libc_res_nquery): If RES_USE_EDNS0 is set try adding EDNS0 record. * resolv/res_send.c (send_dg): If request failed with FORMERR and EDNS0 record was send make sure we don't try it again. * resolv/resolv.h: Define RES_F_EDNS0ERR and RES_USE_EDNS0. * include/resolv.h: Declare __res_nopt.
This commit is contained in:
Ulrich Drepper
parent
00458b5bee
commit
2bbb7d5b3c
11
ChangeLog
11
ChangeLog
@ -1,3 +1,14 @@
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2007-02-09 Ulrich Drepper <drepper@redhat.com>
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* resolv/res_init.c (res_setoptions): Recognize edns0 option.
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* resolv/res_mkquery.c: Define __res_nopt.
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* resolv/res_query.c (__libc_res_nquery): If RES_USE_EDNS0 is set
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try adding EDNS0 record.
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* resolv/res_send.c (send_dg): If request failed with FORMERR and
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EDNS0 record was send make sure we don't try it again.
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* resolv/resolv.h: Define RES_F_EDNS0ERR and RES_USE_EDNS0.
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* include/resolv.h: Declare __res_nopt.
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2007-02-08 Jakub Jelinek <jakub@redhat.com>
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[BZ #3944]
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@ -48,6 +48,8 @@ extern void res_send_setrhook (res_send_rhook __hook);
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extern int res_ourserver_p (const res_state __statp,
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const struct sockaddr_in6 *__inp);
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extern void __res_iclose (res_state statp, bool free_addr);
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extern int __res_nopt(res_state statp, int n0, u_char *buf, int buflen,
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int anslen);
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libc_hidden_proto (__res_ninit)
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libc_hidden_proto (__res_maybe_init)
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libc_hidden_proto (__res_nclose)
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@ -100,6 +102,7 @@ libresolv_hidden_proto (__ns_name_ntop)
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libresolv_hidden_proto (__ns_name_unpack)
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libresolv_hidden_proto (__ns_get16)
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libresolv_hidden_proto (__ns_get32)
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libresolv_hidden_proto (__res_nopt)
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extern const char *_res_opcodes[];
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libresolv_hidden_proto (_res_opcodes)
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@ -510,6 +510,8 @@ res_setoptions(res_state statp, const char *options, const char *source) {
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} else if (!strncmp(cp, "no-check-names",
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sizeof("no-check-names") - 1)) {
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statp->options |= RES_NOCHECKNAME;
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} else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
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statp->options |= RES_USE_EDNS0;
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} else {
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/* XXX - print a warning here? */
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}
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@ -208,3 +208,49 @@ res_nmkquery(res_state statp,
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return (cp - buf);
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}
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libresolv_hidden_def (res_nmkquery)
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/* attach OPT pseudo-RR, as documented in RFC2671 (EDNS0). */
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#ifndef T_OPT
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#define T_OPT 41
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#endif
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int
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__res_nopt(res_state statp,
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int n0, /* current offset in buffer */
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u_char *buf, /* buffer to put query */
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int buflen, /* size of buffer */
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int anslen) /* UDP answer buffer size */
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{
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u_int16_t flags = 0;
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#ifdef DEBUG
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if ((statp->options & RES_DEBUG) != 0U)
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printf(";; res_nopt()\n");
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#endif
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HEADER *hp = (HEADER *) buf;
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u_char *cp = buf + n0;
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u_char *ep = buf + buflen;
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if ((ep - cp) < 1 + RRFIXEDSZ)
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return -1;
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*cp++ = 0; /* "." */
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ns_put16(T_OPT, cp); /* TYPE */
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cp += INT16SZ;
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ns_put16(anslen & 0xffff, cp); /* CLASS = UDP payload size */
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cp += INT16SZ;
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*cp++ = NOERROR; /* extended RCODE */
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*cp++ = 0; /* EDNS version */
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/* XXX Once we support DNSSEC we change the flag value here. */
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ns_put16(flags, cp);
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cp += INT16SZ;
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ns_put16(0, cp); /* RDLEN */
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cp += INT16SZ;
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hp->arcount = htons(ntohs(hp->arcount) + 1);
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return cp - buf;
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}
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libresolv_hidden_def (__res_nopt)
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@ -120,29 +120,44 @@ __libc_res_nquery(res_state statp,
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u_char *buf;
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HEADER *hp = (HEADER *) answer;
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int n, use_malloc = 0;
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u_int oflags = statp->_flags;
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size_t bufsize = QUERYSIZE;
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buf = alloca (bufsize);
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again:
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hp->rcode = NOERROR; /* default */
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buf = alloca (QUERYSIZE);
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_query(%s, %d, %d)\n", name, class, type);
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#endif
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n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
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buf, QUERYSIZE);
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if (__builtin_expect (n <= 0, 0)) {
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buf, bufsize);
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if (n > 0
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&& (oflags & RES_F_EDNS0ERR) == 0
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&& (statp->options & RES_USE_EDNS0) != 0)
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n = __res_nopt(statp, n, buf, bufsize, anslen);
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if (__builtin_expect (n <= 0, 0) && !use_malloc) {
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/* Retry just in case res_nmkquery failed because of too
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short buffer. Shouldn't happen. */
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buf = malloc (MAXPACKET);
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bufsize = MAXPACKET;
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buf = malloc (bufsize);
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if (buf != NULL) {
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use_malloc = 1;
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n = res_nmkquery(statp, QUERY, name, class, type, NULL,
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0, NULL, buf, MAXPACKET);
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goto again;
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}
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}
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if (__builtin_expect (n <= 0, 0)) {
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/* If the query choked with EDNS0, retry without EDNS0. */
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if ((statp->options & RES_USE_EDNS0) != 0
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&& ((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) {
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statp->_flags |= RES_F_EDNS0ERR;
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if (statp->options & RES_DEBUG)
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printf(";; res_nquery: retry without EDNS0\n");
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goto again;
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}
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_query: mkquery failed\n");
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@ -986,6 +986,24 @@ send_dg(res_state statp,
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ans, (resplen > anssiz) ? anssiz : resplen);
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goto wait;
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}
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#ifdef RES_USE_EDNS0
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if (anhp->rcode == FORMERR
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&& (statp->options & RES_USE_EDNS0) != 0U) {
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/*
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* Do not retry if the server do not understand
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* EDNS0. The case has to be captured here, as
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* FORMERR packet do not carry query section, hence
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* res_queriesmatch() returns 0.
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*/
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DprintQ(statp->options & RES_DEBUG,
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(stdout,
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"server rejected query with EDNS0:\n"),
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ans, (resplen > anssiz) ? anssiz : resplen);
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/* record the error */
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statp->_flags |= RES_F_EDNS0ERR;
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goto err_out;
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}
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#endif
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if (!(statp->options & RES_INSECURE2) &&
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!res_queriesmatch(buf, buf + buflen,
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ans, ans + anssiz)) {
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@ -180,6 +180,7 @@ struct res_sym {
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*/
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#define RES_F_VC 0x00000001 /* socket is TCP */
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#define RES_F_CONN 0x00000002 /* socket is connected */
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#define RES_F_EDNS0ERR 0x00000004 /* EDNS0 caused errors */
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/* res_findzonecut() options */
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#define RES_EXHAUSTIVE 0x00000001 /* always do all queries */
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@ -209,6 +210,7 @@ struct res_sym {
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strings */
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#define RES_NOIP6DOTINT 0x00080000 /* Do not use .ip6.int in IPv6
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reverse lookup */
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#define RES_USE_EDNS0 0x00100000 /* Use EDNS0. */
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#define RES_DEFAULT (RES_RECURSE|RES_DEFNAMES|RES_DNSRCH|RES_NOIP6DOTINT)
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