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-rw-r--r--ChangeLog11
-rw-r--r--include/resolv.h3
-rw-r--r--resolv/res_init.c2
-rw-r--r--resolv/res_mkquery.c46
-rw-r--r--resolv/res_query.c29
-rw-r--r--resolv/res_send.c18
-rw-r--r--resolv/resolv.h2
7 files changed, 104 insertions, 7 deletions
diff --git a/ChangeLog b/ChangeLog
index 070da56092..f1b6d3d022 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2007-02-09 Ulrich Drepper <drepper@redhat.com>
+
+ * 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.
+
2007-02-08 Jakub Jelinek <jakub@redhat.com>
[BZ #3944]
diff --git a/include/resolv.h b/include/resolv.h
index 189e4fb58b..c1c89f0ada 100644
--- a/include/resolv.h
+++ b/include/resolv.h
@@ -48,6 +48,8 @@ extern void res_send_setrhook (res_send_rhook __hook);
extern int res_ourserver_p (const res_state __statp,
const struct sockaddr_in6 *__inp);
extern void __res_iclose (res_state statp, bool free_addr);
+extern int __res_nopt(res_state statp, int n0, u_char *buf, int buflen,
+ int anslen);
libc_hidden_proto (__res_ninit)
libc_hidden_proto (__res_maybe_init)
libc_hidden_proto (__res_nclose)
@@ -100,6 +102,7 @@ libresolv_hidden_proto (__ns_name_ntop)
libresolv_hidden_proto (__ns_name_unpack)
libresolv_hidden_proto (__ns_get16)
libresolv_hidden_proto (__ns_get32)
+libresolv_hidden_proto (__res_nopt)
extern const char *_res_opcodes[];
libresolv_hidden_proto (_res_opcodes)
diff --git a/resolv/res_init.c b/resolv/res_init.c
index b5a03d1883..640e087920 100644
--- a/resolv/res_init.c
+++ b/resolv/res_init.c
@@ -510,6 +510,8 @@ res_setoptions(res_state statp, const char *options, const char *source) {
} else if (!strncmp(cp, "no-check-names",
sizeof("no-check-names") - 1)) {
statp->options |= RES_NOCHECKNAME;
+ } else if (!strncmp(cp, "edns0", sizeof("edns0") - 1)) {
+ statp->options |= RES_USE_EDNS0;
} else {
/* XXX - print a warning here? */
}
diff --git a/resolv/res_mkquery.c b/resolv/res_mkquery.c
index fd80569fe2..3fa597fecd 100644
--- a/resolv/res_mkquery.c
+++ b/resolv/res_mkquery.c
@@ -208,3 +208,49 @@ res_nmkquery(res_state statp,
return (cp - buf);
}
libresolv_hidden_def (res_nmkquery)
+
+
+/* attach OPT pseudo-RR, as documented in RFC2671 (EDNS0). */
+#ifndef T_OPT
+#define T_OPT 41
+#endif
+
+int
+__res_nopt(res_state statp,
+ int n0, /* current offset in buffer */
+ u_char *buf, /* buffer to put query */
+ int buflen, /* size of buffer */
+ int anslen) /* UDP answer buffer size */
+{
+ u_int16_t flags = 0;
+
+#ifdef DEBUG
+ if ((statp->options & RES_DEBUG) != 0U)
+ printf(";; res_nopt()\n");
+#endif
+
+ HEADER *hp = (HEADER *) buf;
+ u_char *cp = buf + n0;
+ u_char *ep = buf + buflen;
+
+ if ((ep - cp) < 1 + RRFIXEDSZ)
+ return -1;
+
+ *cp++ = 0; /* "." */
+
+ ns_put16(T_OPT, cp); /* TYPE */
+ cp += INT16SZ;
+ ns_put16(anslen & 0xffff, cp); /* CLASS = UDP payload size */
+ cp += INT16SZ;
+ *cp++ = NOERROR; /* extended RCODE */
+ *cp++ = 0; /* EDNS version */
+ /* XXX Once we support DNSSEC we change the flag value here. */
+ ns_put16(flags, cp);
+ cp += INT16SZ;
+ ns_put16(0, cp); /* RDLEN */
+ cp += INT16SZ;
+ hp->arcount = htons(ntohs(hp->arcount) + 1);
+
+ return cp - buf;
+}
+libresolv_hidden_def (__res_nopt)
diff --git a/resolv/res_query.c b/resolv/res_query.c
index 85bad97d2d..4371af5b05 100644
--- a/resolv/res_query.c
+++ b/resolv/res_query.c
@@ -120,10 +120,13 @@ __libc_res_nquery(res_state statp,
u_char *buf;
HEADER *hp = (HEADER *) answer;
int n, use_malloc = 0;
+ u_int oflags = statp->_flags;
- hp->rcode = NOERROR; /* default */
+ size_t bufsize = QUERYSIZE;
+ buf = alloca (bufsize);
- buf = alloca (QUERYSIZE);
+ again:
+ hp->rcode = NOERROR; /* default */
#ifdef DEBUG
if (statp->options & RES_DEBUG)
@@ -131,18 +134,30 @@ __libc_res_nquery(res_state statp,
#endif
n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
- buf, QUERYSIZE);
- if (__builtin_expect (n <= 0, 0)) {
+ buf, bufsize);
+ if (n > 0
+ && (oflags & RES_F_EDNS0ERR) == 0
+ && (statp->options & RES_USE_EDNS0) != 0)
+ n = __res_nopt(statp, n, buf, bufsize, anslen);
+ if (__builtin_expect (n <= 0, 0) && !use_malloc) {
/* Retry just in case res_nmkquery failed because of too
short buffer. Shouldn't happen. */
- buf = malloc (MAXPACKET);
+ bufsize = MAXPACKET;
+ buf = malloc (bufsize);
if (buf != NULL) {
use_malloc = 1;
- n = res_nmkquery(statp, QUERY, name, class, type, NULL,
- 0, NULL, buf, MAXPACKET);
+ goto again;
}
}
if (__builtin_expect (n <= 0, 0)) {
+ /* If the query choked with EDNS0, retry without EDNS0. */
+ if ((statp->options & RES_USE_EDNS0) != 0
+ && ((oflags ^ statp->_flags) & RES_F_EDNS0ERR) != 0) {
+ statp->_flags |= RES_F_EDNS0ERR;
+ if (statp->options & RES_DEBUG)
+ printf(";; res_nquery: retry without EDNS0\n");
+ goto again;
+ }
#ifdef DEBUG
if (statp->options & RES_DEBUG)
printf(";; res_query: mkquery failed\n");
diff --git a/resolv/res_send.c b/resolv/res_send.c
index 887d048e19..f38c399ffd 100644
--- a/resolv/res_send.c
+++ b/resolv/res_send.c
@@ -986,6 +986,24 @@ send_dg(res_state statp,
ans, (resplen > anssiz) ? anssiz : resplen);
goto wait;
}
+#ifdef RES_USE_EDNS0
+ if (anhp->rcode == FORMERR
+ && (statp->options & RES_USE_EDNS0) != 0U) {
+ /*
+ * Do not retry if the server do not understand
+ * EDNS0. The case has to be captured here, as
+ * FORMERR packet do not carry query section, hence
+ * res_queriesmatch() returns 0.
+ */
+ DprintQ(statp->options & RES_DEBUG,
+ (stdout,
+ "server rejected query with EDNS0:\n"),
+ ans, (resplen > anssiz) ? anssiz : resplen);
+ /* record the error */
+ statp->_flags |= RES_F_EDNS0ERR;
+ goto err_out;
+ }
+#endif
if (!(statp->options & RES_INSECURE2) &&
!res_queriesmatch(buf, buf + buflen,
ans, ans + anssiz)) {
diff --git a/resolv/resolv.h b/resolv/resolv.h
index d7cda117fd..9aa09b8701 100644
--- a/resolv/resolv.h
+++ b/resolv/resolv.h
@@ -180,6 +180,7 @@ struct res_sym {
*/
#define RES_F_VC 0x00000001 /* socket is TCP */
#define RES_F_CONN 0x00000002 /* socket is connected */
+#define RES_F_EDNS0ERR 0x00000004 /* EDNS0 caused errors */
/* res_findzonecut() options */
#define RES_EXHAUSTIVE 0x00000001 /* always do all queries */
@@ -209,6 +210,7 @@ struct res_sym {
strings */
#define RES_NOIP6DOTINT 0x00080000 /* Do not use .ip6.int in IPv6
reverse lookup */
+#define RES_USE_EDNS0 0x00100000 /* Use EDNS0. */
#define RES_DEFAULT (RES_RECURSE|RES_DEFNAMES|RES_DNSRCH|RES_NOIP6DOTINT)
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-17 21:16:12 +0000