[src/trunk]: src/lib/libc/net PR/52578: Benjamin M. Schwartz: sync the intern...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7d959d798a92
branches:  trunk
changeset: 826781:7d959d798a92
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Sep 29 00:04:33 2017 +0000

description:
PR/52578: Benjamin M. Schwartz: sync the internal copy of res_nquery for
getaddrinfo, with the real version so that we handle EDNS fallback.

diffstat:

 lib/libc/net/getaddrinfo.c |  56 +++++++++++++++++++++++++++++++++------------
 1 files changed, 41 insertions(+), 15 deletions(-)

diffs (123 lines):

diff -r 4d78bc64b7ab -r 7d959d798a92 lib/libc/net/getaddrinfo.c
--- a/lib/libc/net/getaddrinfo.c        Thu Sep 28 23:32:01 2017 +0000
+++ b/lib/libc/net/getaddrinfo.c        Fri Sep 29 00:04:33 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: getaddrinfo.c,v 1.115 2017/01/10 17:51:01 christos Exp $       */
+/*     $NetBSD: getaddrinfo.c,v 1.116 2017/09/29 00:04:33 christos Exp $       */
 /*     $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $    */
 
 /*
@@ -55,7 +55,7 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: getaddrinfo.c,v 1.115 2017/01/10 17:51:01 christos Exp $");
+__RCSID("$NetBSD: getaddrinfo.c,v 1.116 2017/09/29 00:04:33 christos Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #ifndef RUMP_ACTION
@@ -2539,13 +2539,14 @@
  */
 static int
 res_queryN(const char *name, /* domain name */ struct res_target *target,
-    res_state res)
+    res_state statp)
 {
        u_char buf[MAXPACKET];
        HEADER *hp;
        int n;
        struct res_target *t;
        int rcode;
+       u_char *rdata;
        int ancount;
 
        _DIAGASSERT(name != NULL);
@@ -2558,8 +2559,12 @@
                int class, type;
                u_char *answer;
                int anslen;
+               u_int oflags;
 
                hp = (HEADER *)(void *)t->answer;
+               oflags = statp->_flags;
+
+again:
                hp->rcode = NOERROR;    /* default */
 
                /* make it easier... */
@@ -2568,42 +2573,63 @@
                answer = t->answer;
                anslen = t->anslen;
 #ifdef DEBUG
-               if (res->options & RES_DEBUG)
+               if (statp->options & RES_DEBUG)
                        printf(";; res_nquery(%s, %d, %d)\n", name, class, type);
 #endif
 
-               n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL,
+               n = res_nmkquery(statp, QUERY, name, class, type, NULL, 0, NULL,
                    buf, (int)sizeof(buf));
 #ifdef RES_USE_EDNS0
-               if (n > 0 && (res->options & RES_USE_EDNS0) != 0)
-                       n = res_nopt(res, n, buf, (int)sizeof(buf), anslen);
+               if (n > 0 && (statp->_flags & RES_F_EDNS0ERR) == 0 &&
+                   (statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0) {
+                       n = res_nopt(statp, n, buf, (int)sizeof(buf), anslen);
+                       rdata = &buf[n];
+                       if (n > 0 && (statp->options & RES_NSID) != 0U) {
+                               n = res_nopt_rdata(statp, n, buf,
+                                   (int)sizeof(buf),
+                                   rdata, NS_OPT_NSID, 0, NULL);
+                       }
+               }
 #endif
                if (n <= 0) {
 #ifdef DEBUG
-                       if (res->options & RES_DEBUG)
+                       if (statp->options & RES_DEBUG)
                                printf(";; res_nquery: mkquery failed\n");
 #endif
                        h_errno = NO_RECOVERY;
                        return n;
                }
-               n = res_nsend(res, buf, n, answer, anslen);
-#if 0
+               n = res_nsend(statp, buf, n, answer, anslen);
                if (n < 0) {
+#ifdef RES_USE_EDNS0
+                       /* if the query choked with EDNS0, retry without EDNS0 */
+                       if ((statp->options & (RES_USE_EDNS0|RES_USE_DNSSEC)) != 0U &&
+                           ((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;
+                       }
+#endif
+#if 0
 #ifdef DEBUG
-                       if (res->options & RES_DEBUG)
+                       if (statp->options & RES_DEBUG)
                                printf(";; res_query: send error\n");
 #endif
                        h_errno = TRY_AGAIN;
                        return n;
+#endif
                }
-#endif
 
                if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
                        rcode = hp->rcode;      /* record most recent error */
 #ifdef DEBUG
-                       if (res->options & RES_DEBUG)
-                               printf(";; rcode = %u, ancount=%u\n", hp->rcode,
-                                   ntohs(hp->ancount));
+                       if (statp->options & RES_DEBUG)
+                               printf(";; rcode = (%s), counts = an:%d ns:%d ar:%d\n",
+                                      p_rcode(hp->rcode),
+                                      ntohs(hp->ancount),
+                                      ntohs(hp->nscount),
+                                      ntohs(hp->arcount));
 #endif
                        continue;
                }