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-rw-r--r--src/basic/in-addr-util.c15
-rw-r--r--src/basic/in-addr-util.h1
-rw-r--r--src/resolve/resolved-dns-packet.h8
-rw-r--r--src/resolve/resolved-dns-transaction.c3
-rw-r--r--src/resolve/resolved-resolv-conf.c31
5 files changed, 44 insertions, 14 deletions
diff --git a/src/basic/in-addr-util.c b/src/basic/in-addr-util.c
index f4e24121e7..1f61b68efd 100644
--- a/src/basic/in-addr-util.c
+++ b/src/basic/in-addr-util.c
@@ -44,7 +44,7 @@ int in_addr_is_link_local(int family, const union in_addr_union *u) {
assert(u);
if (family == AF_INET)
- return (be32toh(u->in.s_addr) & 0xFFFF0000) == (169U << 24 | 254U << 16);
+ return (be32toh(u->in.s_addr) & UINT32_C(0xFFFF0000)) == (UINT32_C(169) << 24 | UINT32_C(254) << 16);
if (family == AF_INET6)
return IN6_IS_ADDR_LINKLOCAL(&u->in6);
@@ -52,6 +52,19 @@ int in_addr_is_link_local(int family, const union in_addr_union *u) {
return -EAFNOSUPPORT;
}
+int in_addr_is_localhost(int family, const union in_addr_union *u) {
+ assert(u);
+
+ if (family == AF_INET)
+ /* All of 127.x.x.x is localhost. */
+ return (be32toh(u->in.s_addr) & UINT32_C(0xFF000000)) == UINT32_C(127) << 24;
+
+ if (family == AF_INET)
+ return IN6_IS_ADDR_LOOPBACK(&u->in6);
+
+ return -EAFNOSUPPORT;
+}
+
int in_addr_equal(int family, const union in_addr_union *a, const union in_addr_union *b) {
assert(a);
assert(b);
diff --git a/src/basic/in-addr-util.h b/src/basic/in-addr-util.h
index 51af08868c..58f55b3418 100644
--- a/src/basic/in-addr-util.h
+++ b/src/basic/in-addr-util.h
@@ -33,6 +33,7 @@ union in_addr_union {
int in_addr_is_null(int family, const union in_addr_union *u);
int in_addr_is_link_local(int family, const union in_addr_union *u);
+int in_addr_is_localhost(int family, const union in_addr_union *u);
int in_addr_equal(int family, const union in_addr_union *a, const union in_addr_union *b);
int in_addr_prefix_intersect(int family, const union in_addr_union *a, unsigned aprefixlen, const union in_addr_union *b, unsigned bprefixlen);
int in_addr_prefix_next(int family, union in_addr_union *u, unsigned prefixlen);
diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h
index 48df5dfc53..90b5a7c8bd 100644
--- a/src/resolve/resolved-dns-packet.h
+++ b/src/resolve/resolved-dns-packet.h
@@ -177,6 +177,14 @@ void dns_packet_rewind(DnsPacket *p, size_t idx);
int dns_packet_skip_question(DnsPacket *p);
int dns_packet_extract(DnsPacket *p);
+static inline bool DNS_PACKET_SHALL_CACHE(DnsPacket *p) {
+ /* Never cache data originating from localhost, under the
+ * assumption, that it's coming from a locally DNS forwarder
+ * or server, that is caching on its own. */
+
+ return in_addr_is_localhost(p->family, &p->sender) == 0;
+}
+
enum {
DNS_RCODE_SUCCESS = 0,
DNS_RCODE_FORMERR = 1,
diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index c65c9c9f49..8c4f23a4da 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -478,7 +478,8 @@ void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) {
}
/* According to RFC 4795, section 2.9. only the RRs from the answer section shall be cached */
- dns_cache_put(&t->scope->cache, t->key, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
+ if (DNS_PACKET_SHALL_CACHE(p))
+ dns_cache_put(&t->scope->cache, t->key, DNS_PACKET_RCODE(p), p->answer, DNS_PACKET_ANCOUNT(p), 0, p->family, &p->sender);
if (DNS_PACKET_RCODE(p) == DNS_RCODE_SUCCESS)
dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS);
diff --git a/src/resolve/resolved-resolv-conf.c b/src/resolve/resolved-resolv-conf.c
index 744969b745..956f380f3c 100644
--- a/src/resolve/resolved-resolv-conf.c
+++ b/src/resolve/resolved-resolv-conf.c
@@ -50,9 +50,9 @@ int manager_read_resolv_conf(Manager *m) {
r = stat("/etc/resolv.conf", &st);
if (r < 0) {
if (errno == ENOENT)
- r = 0;
- else
- r = log_warning_errno(errno, "Failed to stat /etc/resolv.conf: %m");
+ return 0;
+
+ r = log_warning_errno(errno, "Failed to stat /etc/resolv.conf: %m");
goto clear;
}
@@ -61,22 +61,18 @@ int manager_read_resolv_conf(Manager *m) {
if (t == m->resolv_conf_mtime)
return 0;
- m->resolv_conf_mtime = t;
-
/* Is it symlinked to our own file? */
if (stat("/run/systemd/resolve/resolv.conf", &own) >= 0 &&
st.st_dev == own.st_dev &&
- st.st_ino == own.st_ino) {
- r = 0;
- goto clear;
- }
+ st.st_ino == own.st_ino)
+ return 0;
f = fopen("/etc/resolv.conf", "re");
if (!f) {
if (errno == ENOENT)
- r = 0;
- else
- r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
+ return 0;
+
+ r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m");
goto clear;
}
@@ -115,6 +111,8 @@ int manager_read_resolv_conf(Manager *m) {
}
}
+ m->resolv_conf_mtime = t;
+
/* Flush out all servers and search domains that are still
* marked. Those are then ones that didn't appear in the new
* /etc/resolv.conf */
@@ -131,6 +129,15 @@ int manager_read_resolv_conf(Manager *m) {
* resolve VPN domains. */
manager_set_dns_server(m, m->dns_servers);
+ /* Unconditionally flush the cache when /etc/resolv.conf is
+ * modified, even if the data it contained was completely
+ * identical to the previous version we used. We do this
+ * because altering /etc/resolv.conf is typically done when
+ * the network configuration changes, and that should be
+ * enough to flush the global unicast DNS cache. */
+ if (m->unicast_scope)
+ dns_cache_flush(&m->unicast_scope->cache);
+
return 0;
clear:
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-09 01:31:56 +0000