[PATCH 2/4] resolv: Do not wait for non-existing second DNS response after error (bug 30081)
DJ Delorie
dj@redhat.com
Thu Jun 20 20:41:42 GMT 2024
Florian Weimer <fweimer@redhat.com> writes:
> + tst-resolv-semi-failure \
Ok.
> +$(objpfx)tst-resolv-semi-failure: $(objpfx)libresolv.so \
> + $(shared-thread-library)
Ok.
> diff --git a/resolv/res_send.c b/resolv/res_send.c
> index 572e72c32f..9c77613f37 100644
> --- a/resolv/res_send.c
> +++ b/resolv/res_send.c
> @@ -1238,7 +1238,7 @@ send_dg(res_state statp,
> *resplen2 = 0;
> return resplen;
> }
> - if (buf2 != NULL)
> + if (buf2 != NULL && !single_request)
Ok, don't check for the second answer if we didn't send a second query.
> diff --git a/resolv/tst-resolv-semi-failure.c b/resolv/tst-resolv-semi-failure.c
> new file mode 100644
> index 0000000000..aa9798b5a7
> --- /dev/null
> +++ b/resolv/tst-resolv-semi-failure.c
> @@ -0,0 +1,133 @@
> +/* Test parallel failure/success responses (bug 30081).
> + Copyright (C) 2024 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
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <resolv.h>
> +#include <support/check.h>
> +#include <support/resolv_test.h>
> +#include <support/check_nss.h>
Ok.
> +/* The rcode in the initial response. */
> +static volatile int rcode;
> +
> +/* Whether to fail the initial A query (!fail_aaaa) or the initial
> + AAAA query (fail_aaaa). */
> +static volatile bool fail_aaaa;
> +
> +static void
> +response (const struct resolv_response_context *ctx,
> + struct resolv_response_builder *b,
> + const char *qname, uint16_t qclass, uint16_t qtype)
> +{
> + /* Handle the failing query. */
> + if ((fail_aaaa && qtype == T_AAAA) && ctx->server_index == 0)
> + {
> + struct resolv_response_flags flags = {.rcode = rcode};
> + resolv_response_init (b, flags);
> + return;
> + }
Ok.
> + /* Otherwise produce a response. */
> + resolv_response_init (b, (struct resolv_response_flags) {});
> + resolv_response_add_question (b, qname, qclass, qtype);
> + resolv_response_section (b, ns_s_an);
> + resolv_response_open_record (b, qname, qclass, qtype, 0);
> + switch (qtype)
> + {
> + case T_A:
> + {
> + char ipv4[4] = {192, 0, 2, 17};
> + resolv_response_add_data (b, &ipv4, sizeof (ipv4));
> + }
> + break;
> + case T_AAAA:
> + {
> + char ipv6[16]
> + = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
> + resolv_response_add_data (b, &ipv6, sizeof (ipv6));
> + }
> + break;
Ok.
> + default:
> + FAIL_EXIT1 ("unexpected TYPE%d query", qtype);
> + }
> + resolv_response_close_record (b);
> +}
Ok.
> +static void
> +check_one (void)
> +{
> +
> + /* The buggy 1-second query timeout results in 30 seconds of delay,
> + which triggers are test timeout failure. */
Same comment here - can we rely on this?
> + for (int i = 0; i < 30; ++i)
> + {
> + static const struct addrinfo hints =
> + {
> + .ai_family = AF_UNSPEC,
> + .ai_socktype = SOCK_STREAM,
> + };
> + struct addrinfo *ai;
> + int ret = getaddrinfo ("www.example", "80", &hints, &ai);
> + const char *expected;
> + if (ret == 0 && ai->ai_next != NULL)
> + expected = ("address: STREAM/TCP 192.0.2.17 80\n"
> + "address: STREAM/TCP 2001:db8::1 80\n");
> + else
> + /* Only one response because the AAAA lookup failure is
> + treated as an ignoreable error. */
> + expected = "address: STREAM/TCP 192.0.2.17 80\n";
> + check_addrinfo ("www.example", ai, ret, expected);
> + if (ret == 0)
> + freeaddrinfo (ai);
> + }
> +}
Ok.
> +static int
> +do_test (void)
> +{
> + for (int do_single_lookup = 0; do_single_lookup < 2; ++do_single_lookup)
> + {
> + struct resolv_test *aux = resolv_test_start
> + ((struct resolv_redirect_config)
> + {
> + .response_callback = response,
> + });
> +
> + if (do_single_lookup)
> + _res.options |= RES_SNGLKUP;
Ok.
> + for (int do_fail_aaaa = 0; do_fail_aaaa < 2; ++do_fail_aaaa)
> + {
> + fail_aaaa = do_fail_aaaa;
Ok.
> + rcode = 2; /* SERVFAIL. */
> + check_one ();
> +
> + rcode = 4; /* NOTIMP. */
> + check_one ();
> +
> + rcode = 5; /* REFUSED. */
> + check_one ();
> + }
> +
> + resolv_test_end (aux);
> + }
> +
> + return 0;
> +}
Ok.
> +#include <support/test-driver.c>
> diff --git a/resolv/tst-resolv-short-response.c b/resolv/tst-resolv-short-response.c
> index 0647de0704..a6ea456e46 100644
> --- a/resolv/tst-resolv-short-response.c
> +++ b/resolv/tst-resolv-short-response.c
> @@ -81,6 +81,18 @@ check_one (void)
> check_hostent ("www.example", gethostbyname2 ("www.example", AF_INET6),
> "name: www.example\n"
> "address: 2001:db8::1\n");
> + static const struct addrinfo hints =
> + {
> + .ai_family = AF_UNSPEC,
> + .ai_socktype = SOCK_STREAM,
> + };
> + struct addrinfo *ai;
> + int ret = getaddrinfo ("www.example", "80", &hints, &ai);
> + check_addrinfo ("www.example", ai, ret,
> + "address: STREAM/TCP 192.0.2.17 80\n"
> + "address: STREAM/TCP 2001:db8::1 80\n");
> + if (ret == 0)
> + freeaddrinfo (ai);
> }
> }
Ok.
More information about the Libc-alpha
mailing list