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https://github.com/RIOT-OS/RIOT.git
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Merge pull request #20857 from benpicco/dns_msg-fix_skip
dns_msg: skip RDLENGTH_LENGTH field when skipping record
This commit is contained in:
benpicco
GitHub
commit
9bdb697edb
@ -26,6 +26,9 @@
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#include "net/dns/msg.h"
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#define ENABLE_DEBUG 0
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#include "debug.h"
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static ssize_t _enc_domain_name(uint8_t *out, const char *domain_name)
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{
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/*
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@ -76,10 +79,13 @@ static ssize_t _skip_hostname(const uint8_t *buf, size_t len,
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if (bufpos >= buflim) {
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/* out-of-bound */
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DEBUG("dns_msg: bufpos is out of bounds\n");
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return -EBADMSG;
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}
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/* handle DNS Message Compression */
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if (*bufpos >= 192) {
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if (*bufpos & 0xc0) {
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DEBUG("dns_msg: hostname is compressed\n");
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if ((bufpos + 2) >= buflim) {
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return -EBADMSG;
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}
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@ -90,6 +96,7 @@ static ssize_t _skip_hostname(const uint8_t *buf, size_t len,
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res += bufpos[res] + 1;
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if ((&bufpos[res]) >= buflim) {
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/* out-of-bound */
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DEBUG("dns_msg: hostname out-of-bounds\n");
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return -EBADMSG;
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}
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}
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@ -156,6 +163,7 @@ int dns_msg_parse_reply(const uint8_t *buf, size_t len, int family,
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bufpos += tmp;
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if ((bufpos + RR_TYPE_LENGTH + RR_CLASS_LENGTH +
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RR_TTL_LENGTH + sizeof(uint16_t)) >= buflim) {
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DEBUG("dns_msg: record beyond buf limit");
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return -EBADMSG;
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}
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uint16_t _type = ntohs(_get_short(bufpos));
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@ -167,35 +175,38 @@ int dns_msg_parse_reply(const uint8_t *buf, size_t len, int family,
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}
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bufpos += RR_TTL_LENGTH;
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unsigned addrlen = ntohs(_get_short(bufpos));
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unsigned rdlen = ntohs(_get_short(bufpos));
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bufpos += RR_RDLENGTH_LENGTH;
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if ((bufpos + rdlen) > buflim) {
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return -EBADMSG;
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}
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DEBUG("dns_msg: type: %u, class: %u, len: %u\n", _type, class, rdlen);
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/* skip unwanted answers */
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if ((class != DNS_CLASS_IN) ||
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((_type == DNS_TYPE_A) && (family == AF_INET6)) ||
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((_type == DNS_TYPE_AAAA) && (family == AF_INET)) ||
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! ((_type == DNS_TYPE_A) || ((_type == DNS_TYPE_AAAA))
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)) {
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if (addrlen > len) {
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if (rdlen > len) {
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/* buffer wraps around memory space */
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return -EBADMSG;
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}
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bufpos += addrlen;
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bufpos += rdlen;
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/* other out-of-bound is checked in `_skip_hostname()` at start of
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* loop */
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continue;
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}
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if (((addrlen != INADDRSZ) && (family == AF_INET)) ||
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((addrlen != IN6ADDRSZ) && (family == AF_INET6)) ||
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((addrlen != IN6ADDRSZ) && (addrlen != INADDRSZ) &&
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if (((rdlen != INADDRSZ) && (family == AF_INET)) ||
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((rdlen != IN6ADDRSZ) && (family == AF_INET6)) ||
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((rdlen != IN6ADDRSZ) && (rdlen != INADDRSZ) &&
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(family == AF_UNSPEC))) {
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return -EBADMSG;
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}
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bufpos += RR_RDLENGTH_LENGTH;
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if ((bufpos + addrlen) > buflim) {
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return -EBADMSG;
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}
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memcpy(addr_out, bufpos, addrlen);
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return addrlen;
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memcpy(addr_out, bufpos, rdlen);
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return rdlen;
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}
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return -EBADMSG;
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@ -20,6 +20,7 @@
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#include <string.h>
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#include <arpa/inet.h>
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#include <string.h>
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#include "net/dns.h"
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#include "net/dns/cache.h"
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@ -27,6 +28,9 @@
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#include "net/sock/udp.h"
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#include "net/sock/dns.h"
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#define ENABLE_DEBUG 0
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#include "debug.h"
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/* min domain name length is 1, so minimum record length is 7 */
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#define DNS_MIN_REPLY_LEN (unsigned)(sizeof(dns_hdr_t) + 7)
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@ -87,7 +91,7 @@ int sock_dns_query(const char *domain_name, void *addr_out, int family)
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res = sock_udp_create(&sock_dns, NULL, &sock_dns_server, 0);
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if (res) {
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goto out;
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return res;
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}
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uint16_t id = 0;
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@ -96,25 +100,30 @@ int sock_dns_query(const char *domain_name, void *addr_out, int family)
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res = sock_udp_send(&sock_dns, dns_buf, buflen, NULL);
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if (res <= 0) {
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DEBUG("sock_dns: can't send: %s\n", strerror(-res));
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continue;
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}
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res = sock_udp_recv(&sock_dns, dns_buf, sizeof(dns_buf), 1000000LU, NULL);
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if (res > 0) {
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if (res > (int)DNS_MIN_REPLY_LEN) {
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uint32_t ttl;
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if ((res = dns_msg_parse_reply(dns_buf, res, family,
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addr_out, &ttl)) > 0) {
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dns_cache_add(domain_name, addr_out, res, ttl);
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goto out;
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}
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}
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else {
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res = -EBADMSG;
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}
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if (res < 0) {
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DEBUG("sock_dns: can't receive: %s\n", strerror(-res));
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continue;
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}
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if (res < (int)DNS_MIN_REPLY_LEN) {
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DEBUG("sock_dns: reply too small (%d byte)\n", (int)res);
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res = -EBADMSG;
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continue;
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}
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uint32_t ttl;
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if ((res = dns_msg_parse_reply(dns_buf, res, family,
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addr_out, &ttl)) > 0) {
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dns_cache_add(domain_name, addr_out, res, ttl);
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break;
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} else {
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DEBUG("sock_dns: can't parse response\n");
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}
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}
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out:
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sock_udp_close(&sock_dns);
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return res;
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}
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1
tests/unittests/tests-dns_msg/Makefile
Normal file
1
tests/unittests/tests-dns_msg/Makefile
Normal file
@ -0,0 +1 @@
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include $(RIOTBASE)/Makefile.base
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5
tests/unittests/tests-dns_msg/Makefile.include
Normal file
5
tests/unittests/tests-dns_msg/Makefile.include
Normal file
@ -0,0 +1,5 @@
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USEMODULE += dns_msg
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USEMODULE += gnrc_ipv6
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USEMODULE += sock_udp
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USEMODULE += posix_inet
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159
tests/unittests/tests-dns_msg/tests-dns_msg.c
Normal file
159
tests/unittests/tests-dns_msg/tests-dns_msg.c
Normal file
@ -0,0 +1,159 @@
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/*
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* Copyright (C) 2024 ML!PA Consulting GmbH
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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#include <stdint.h>
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#include <string.h>
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#include "net/af.h"
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#include "net/ipv6.h"
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#include "ztimer.h"
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#include "net/dns/msg.h"
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#include "tests-dns_msg.h"
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static void test_dns_msg_valid_AAAA(void)
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{
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const uint8_t dns_msg[] = {
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/* in scapy notation:
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* <DNS id=0 qr=1 opcode=QUERY aa=0 tc=0 rd=1 ra=1 z=0 ad=0 cd=0 rcode=ok
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* qdcount=1 ancount=1 nscount=0 arcount=0
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* qd=<DNSQR qname='example.org.' qtype=AAAA qclass=IN |>
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* an=<DNSRR rrname='\\xc0\x0c' type=AAAA rclass=IN ttl=300
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* rdata=2001:db8:4005:80b::200e |>
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* ns=None ar=None |> */
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0x00, 0x00, 0x81, 0x80, 0x00, 0x01, 0x00, 0x01,
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0x00, 0x00, 0x00, 0x00, 0x07, 0x65, 0x78, 0x61,
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0x6d, 0x70, 0x6c, 0x65, 0x03, 0x6f, 0x72, 0x67,
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0x00, 0x00, 0x1c, 0x00, 0x01, 0xc0, 0x0c, 0x00,
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0x1c, 0x00, 0x01, 0x00, 0x00, 0x01, 0x2c, 0x00,
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0x10, 0x20, 0x01, 0x0d, 0xb8, 0x40, 0x05, 0x08,
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0x0b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20,
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0x0e
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};
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const uint8_t addr[] = {
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/* 2001:db8:4005:80b::200e */
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0x20, 0x01, 0x0d, 0xb8, 0x40, 0x05, 0x08, 0x0b,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x0e,
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};
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const uint32_t ttl = 300;
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uint8_t addr_out[16];
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uint32_t ttl_out;
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int res = dns_msg_parse_reply(dns_msg, sizeof(dns_msg), AF_INET6, &addr_out, &ttl_out);
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TEST_ASSERT_EQUAL_INT(16, res);
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TEST_ASSERT_EQUAL_INT(ttl, ttl_out);
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TEST_ASSERT_EQUAL_INT(0, memcmp(addr, addr_out, sizeof(addr)));
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}
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static void test_dns_msg_valid_dns64(void)
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{
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const uint8_t dns_msg[] = {
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/* in scapy notation:
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* <DNS id=0 qr=1 opcode=QUERY aa=0 tc=0 rd=1 ra=1 z=0 ad=0 cd=0 rcode=ok
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qdcount=1 ancount=1 nscount=0 arcount=0
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qd=<DNSQR qname='example.org.' qtype=AAAA qclass=IN |>
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an=<DNSRR rrname='\\xc0\x0c' type=AAAA rclass=IN ttl=60
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rdata=2001:db8:2b0:db32:0:1:8c52:7903 |>
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ns=None ar=None |> */
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0x00, 0x00, 0x81, 0x80, 0x00, 0x01, 0x00, 0x01,
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0x00, 0x00, 0x00, 0x00, 0x07, 0x65, 0x78, 0x61,
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0x6d, 0x70, 0x6c, 0x65, 0x03, 0x6f, 0x72, 0x67,
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0x00, 0x00, 0x1c, 0x00, 0x01, 0xc0, 0x0c, 0x00,
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0x1c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x3c, 0x00,
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0x10, 0x20, 0x01, 0x0d, 0xb8, 0x02, 0xb0, 0xdb,
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0x32, 0x00, 0x00, 0x00, 0x01, 0x8c, 0x52, 0x79,
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0x03
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};
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const uint8_t addr[] = {
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/* 2001:db8:2b0:db32:0:1:8c52:7903 */
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0x20, 0x01, 0x0d, 0xb8, 0x02, 0xb0, 0xdb, 0x32,
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0x00, 0x00, 0x00, 0x01, 0x8c, 0x52, 0x79, 0x03,
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};
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const uint32_t ttl = 60;
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uint8_t addr_out[16];
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uint32_t ttl_out;
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int res = dns_msg_parse_reply(dns_msg, sizeof(dns_msg), AF_INET6, &addr_out, &ttl_out);
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TEST_ASSERT_EQUAL_INT(16, res);
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TEST_ASSERT_EQUAL_INT(ttl, ttl_out);
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TEST_ASSERT_EQUAL_INT(0, memcmp(addr, addr_out, sizeof(addr)));
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}
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static void test_dns_msg_valid_dns64_w_long_cnames(void)
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{
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const uint8_t dns_msg[] = {
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/* in scapy notation:
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* <DNS id=0 qr=1 opcode=QUERY aa=0 tc=0 rd=1 ra=1 z=0 ad=0 cd=0 rcode=ok
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* qdcount=1 ancount=3 nscount=0 arcount=0
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* qd=<DNSQR qname='the.too.long.name.for.the.example.net.' qtype=AAAA qclass=IN |>
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* an=<DNSRR rrname='\\xc0\x0c' type=CNAME rclass=IN ttl=600
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* rdata='the.too.long.name.for.the.example.net.' |
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* <DNSRR rrname='\\xc0C' type=CNAME rclass=IN ttl=90
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* rdata='this-is-becoming-ridic.ulous.naming.cloud.example.com.' |
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* <DNSRR rrname='\\xc0p' type=AAAA rclass=IN ttl=10
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* rdata=2001:db8:2b0:db32:0:1:1432:418d |>>>
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* ns=None ar=None |>
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*/
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0x00, 0x00, 0x81, 0x80, 0x00, 0x01, 0x00, 0x03,
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0x00, 0x00, 0x00, 0x00, 0x03, 0x74, 0x68, 0x65,
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0x03, 0x74, 0x6f, 0x6f, 0x04, 0x6c, 0x6f, 0x6e,
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0x67, 0x04, 0x6e, 0x61, 0x6d, 0x65, 0x03, 0x66,
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0x6f, 0x72, 0x03, 0x74, 0x68, 0x65, 0x07, 0x65,
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0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x03, 0x6e,
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0x65, 0x74, 0x00, 0x00, 0x1c, 0x00, 0x01, 0xc0,
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0x0c, 0x00, 0x05, 0x00, 0x01, 0x00, 0x00, 0x02,
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0x58, 0x00, 0x21, 0x03, 0x74, 0x68, 0x65, 0x04,
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0x65, 0x76, 0x65, 0x6e, 0x10, 0x6c, 0x6f, 0x6f,
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0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
|
||||
0x6f, 0x6e, 0x67, 0x65, 0x72, 0x04, 0x6e, 0x61,
|
||||
0x6d, 0x65, 0xc0, 0x26, 0xc0, 0x43, 0x00, 0x05,
|
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0x00, 0x01, 0x00, 0x00, 0x00, 0x5a, 0x00, 0x37,
|
||||
0x16, 0x74, 0x68, 0x69, 0x73, 0x2d, 0x69, 0x73,
|
||||
0x2d, 0x62, 0x65, 0x63, 0x6f, 0x6d, 0x69, 0x6e,
|
||||
0x67, 0x2d, 0x72, 0x69, 0x64, 0x69, 0x63, 0x05,
|
||||
0x75, 0x6c, 0x6f, 0x75, 0x73, 0x06, 0x6e, 0x61,
|
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0x6d, 0x69, 0x6e, 0x67, 0x05, 0x63, 0x6c, 0x6f,
|
||||
0x75, 0x64, 0x07, 0x65, 0x78, 0x61, 0x6d, 0x70,
|
||||
0x6c, 0x65, 0x03, 0x63, 0x6f, 0x6d, 0x00, 0xc0,
|
||||
0x70, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x00,
|
||||
0x0a, 0x00, 0x10, 0x20, 0x01, 0x0d, 0xb8, 0x02,
|
||||
0xb0, 0xdb, 0x32, 0x00, 0x00, 0x00, 0x01, 0x14,
|
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0x32, 0x41, 0x8d
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};
|
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const uint8_t addr[] = {
|
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/* 2001:db8:2b0:db32:0:1:1432:418d */
|
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0x20, 0x01, 0x0d, 0xb8, 0x02, 0xb0, 0xdb, 0x32,
|
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0x00, 0x00, 0x00, 0x01, 0x14, 0x32, 0x41, 0x8d,
|
||||
};
|
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const uint32_t ttl = 10;
|
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|
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uint8_t addr_out[16];
|
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uint32_t ttl_out;
|
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int res = dns_msg_parse_reply(dns_msg, sizeof(dns_msg), AF_INET6, &addr_out, &ttl_out);
|
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TEST_ASSERT_EQUAL_INT(16, res);
|
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TEST_ASSERT_EQUAL_INT(ttl, ttl_out);
|
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TEST_ASSERT_EQUAL_INT(0, memcmp(addr, addr_out, sizeof(addr)));
|
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}
|
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|
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Test *tests_dns_msg_tests(void)
|
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{
|
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EMB_UNIT_TESTFIXTURES(fixtures) {
|
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new_TestFixture(test_dns_msg_valid_AAAA),
|
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new_TestFixture(test_dns_msg_valid_dns64),
|
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new_TestFixture(test_dns_msg_valid_dns64_w_long_cnames),
|
||||
};
|
||||
|
||||
EMB_UNIT_TESTCALLER(dns_msg_tests, NULL, NULL, fixtures);
|
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|
||||
return (Test *)&dns_msg_tests;
|
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}
|
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|
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void tests_dns_msg(void)
|
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{
|
||||
TESTS_RUN(tests_dns_msg_tests());
|
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}
|
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44
tests/unittests/tests-dns_msg/tests-dns_msg.h
Normal file
44
tests/unittests/tests-dns_msg/tests-dns_msg.h
Normal file
@ -0,0 +1,44 @@
|
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/*
|
||||
* Copyright (C) 2024 ML!PA Consulting GmbH
|
||||
*
|
||||
* This file is subject to the terms and conditions of the GNU Lesser
|
||||
* General Public License v2.1. See the file LICENSE in the top level
|
||||
* directory for more details.
|
||||
*/
|
||||
|
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/**
|
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* @addtogroup unittests
|
||||
* @{
|
||||
*
|
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* @file
|
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* @brief Unittests for the `dns_msg` module
|
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*
|
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* @author Benjamin Valentin <benjamin.valentin@ml-pa.com>
|
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*/
|
||||
#ifndef TESTS_DNS_MSG_H
|
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#define TESTS_DNS_MSG_H
|
||||
|
||||
#include "embUnit.h"
|
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|
||||
#ifdef __cplusplus
|
||||
extern "C" {
|
||||
#endif
|
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|
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/**
|
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* @brief The entry point of this test suite.
|
||||
*/
|
||||
void tests_dns_msg(void);
|
||||
|
||||
/**
|
||||
* @brief Generates tests for dns_msg
|
||||
*
|
||||
* @return embUnit tests if successful, NULL if not.
|
||||
*/
|
||||
Test *tests_dns_msg_tests(void);
|
||||
|
||||
#ifdef __cplusplus
|
||||
}
|
||||
#endif
|
||||
|
||||
#endif /* TESTS_DNS_MSG_H */
|
||||
/** @} */
|
||||
Loading…
Reference in New Issue
Block a user