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-rw-r--r--src/resolve/resolved-dns-cache.c18
-rw-r--r--src/resolve/resolved-dns-packet.c66
-rw-r--r--src/resolve/resolved-dns-packet.h5
-rw-r--r--src/resolve/resolved-dns-scope.c33
-rw-r--r--src/resolve/resolved-llmnr.c4
-rw-r--r--src/resolve/resolved-mdns.c4
6 files changed, 101 insertions, 29 deletions
diff --git a/src/resolve/resolved-dns-cache.c b/src/resolve/resolved-dns-cache.c
index 6124ff659c..1774ae6cb8 100644
--- a/src/resolve/resolved-dns-cache.c
+++ b/src/resolve/resolved-dns-cache.c
@@ -738,6 +738,7 @@ int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) {
int r;
assert(cache);
+ assert(p);
HASHMAP_FOREACH(i, cache->by_key, iterator) {
DnsCacheItem *j;
@@ -752,6 +753,23 @@ int dns_cache_export_shared_to_packet(DnsCache *cache, DnsPacket *p) {
continue;
r = dns_packet_append_rr(p, j->rr, NULL, NULL);
+ if (r == -EMSGSIZE && p->protocol == DNS_PROTOCOL_MDNS) {
+ /* For mDNS, if we're unable to stuff all known answers into the given packet,
+ * allocate a new one, push the RR into that one and link it to the current one.
+ */
+
+ DNS_PACKET_HEADER(p)->ancount = htobe16(ancount);
+ ancount = 0;
+
+ r = dns_packet_new_query(&p->more, p->protocol, 0, true);
+ if (r < 0)
+ return r;
+
+ /* continue with new packet */
+ p = p->more;
+ r = dns_packet_append_rr(p, j->rr, NULL, NULL);
+ }
+
if (r < 0)
return r;
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index 9bd08eeec2..f753b3522f 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -65,40 +65,44 @@ int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
return 0;
}
-int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled) {
- DnsPacket *p;
- DnsPacketHeader *h;
- int r;
+void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated) {
- assert(ret);
+ DnsPacketHeader *h;
- r = dns_packet_new(&p, protocol, mtu);
- if (r < 0)
- return r;
+ assert(p);
h = DNS_PACKET_HEADER(p);
- if (protocol == DNS_PROTOCOL_LLMNR)
+ switch(p->protocol) {
+ case DNS_PROTOCOL_LLMNR:
+ assert(!truncated);
+
h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
0 /* opcode */,
0 /* c */,
- 0 /* tc */,
+ 0/* tc */,
0 /* t */,
0 /* ra */,
0 /* ad */,
0 /* cd */,
0 /* rcode */));
- else if (protocol == DNS_PROTOCOL_MDNS)
- h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
- 0 /* opcode */,
- 0 /* aa */,
- 0 /* tc */,
- 0 /* rd (ask for recursion) */,
- 0 /* ra */,
- 0 /* ad */,
- 0 /* cd */,
- 0 /* rcode */));
- else
+ break;
+
+ case DNS_PROTOCOL_MDNS:
+ h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
+ 0 /* opcode */,
+ 0 /* aa */,
+ truncated /* tc */,
+ 0 /* rd (ask for recursion) */,
+ 0 /* ra */,
+ 0 /* ad */,
+ 0 /* cd */,
+ 0 /* rcode */));
+ break;
+
+ default:
+ assert(!truncated);
+
h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
0 /* opcode */,
0 /* aa */,
@@ -108,6 +112,23 @@ int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu, bool
0 /* ad */,
dnssec_checking_disabled /* cd */,
0 /* rcode */));
+ }
+}
+
+int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled) {
+ DnsPacket *p;
+ int r;
+
+ assert(ret);
+
+ r = dns_packet_new(&p, protocol, mtu);
+ if (r < 0)
+ return r;
+
+ /* Always set the TC bit to 0 initially.
+ * If there are multiple packets later, we'll update the bit shortly before sending.
+ */
+ dns_packet_set_flags(p, dnssec_checking_disabled, false);
*ret = p;
return 0;
@@ -149,6 +170,9 @@ DnsPacket *dns_packet_unref(DnsPacket *p) {
assert(p->n_ref > 0);
+ if (p->more)
+ dns_packet_unref(p->more);
+
if (p->n_ref == 1)
dns_packet_free(p);
else
diff --git a/src/resolve/resolved-dns-packet.h b/src/resolve/resolved-dns-packet.h
index 48b3572cb4..3d84cb622b 100644
--- a/src/resolve/resolved-dns-packet.h
+++ b/src/resolve/resolved-dns-packet.h
@@ -88,6 +88,9 @@ struct DnsPacket {
uint16_t sender_port, destination_port;
uint32_t ttl;
+ /* For support of truncated packets */
+ DnsPacket *more;
+
bool on_stack:1;
bool extracted:1;
bool refuse_compression:1;
@@ -146,6 +149,8 @@ static inline unsigned DNS_PACKET_RRCOUNT(DnsPacket *p) {
int dns_packet_new(DnsPacket **p, DnsProtocol protocol, size_t mtu);
int dns_packet_new_query(DnsPacket **p, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled);
+void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated);
+
DnsPacket *dns_packet_ref(DnsPacket *p);
DnsPacket *dns_packet_unref(DnsPacket *p);
diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c
index eae903526b..4d83ac597c 100644
--- a/src/resolve/resolved-dns-scope.c
+++ b/src/resolve/resolved-dns-scope.c
@@ -161,7 +161,7 @@ void dns_scope_packet_lost(DnsScope *s, usec_t usec) {
s->resend_timeout = MIN(s->resend_timeout * 2, MULTICAST_RESEND_TIMEOUT_MAX_USEC);
}
-int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
+static int dns_scope_emit_one(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
union in_addr_union addr;
int ifindex = 0, r;
int family;
@@ -278,6 +278,31 @@ int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
return 1;
}
+int dns_scope_emit(DnsScope *s, int fd, DnsServer *server, DnsPacket *p) {
+ int r;
+
+ assert(s);
+ assert(p);
+ assert(p->protocol == s->protocol);
+ assert((s->protocol == DNS_PROTOCOL_DNS) != (fd < 0));
+
+ do {
+ /* If there are multiple linked packets, set the TC bit in all but the last of them */
+ if (p->more) {
+ assert(p->protocol == DNS_PROTOCOL_MDNS);
+ dns_packet_set_flags(p, true, true);
+ }
+
+ r = dns_scope_emit_one(s, fd, server, p);
+ if (r < 0)
+ return r;
+
+ p = p->more;
+ } while(p);
+
+ return 0;
+}
+
static int dns_scope_socket(DnsScope *s, int type, int family, const union in_addr_union *address, uint16_t port, DnsServer **server) {
DnsServer *srv = NULL;
_cleanup_close_ int fd = -1;
@@ -433,7 +458,11 @@ DnsScopeMatch dns_scope_good_domain(DnsScope *s, int ifindex, uint64_t flags, co
dns_name_endswith(domain, "8.e.f.ip6.arpa") == 0 &&
dns_name_endswith(domain, "9.e.f.ip6.arpa") == 0 &&
dns_name_endswith(domain, "a.e.f.ip6.arpa") == 0 &&
- dns_name_endswith(domain, "b.e.f.ip6.arpa") == 0)
+ dns_name_endswith(domain, "b.e.f.ip6.arpa") == 0 &&
+ /* If networks use .local in their private setups, they are supposed to also add .local to their search
+ * domains, which we already checked above. Otherwise, we consider .local specific to mDNS and won't
+ * send such queries ordinary DNS servers. */
+ dns_name_endswith(domain, "local") == 0)
return DNS_SCOPE_MAYBE;
return DNS_SCOPE_NO;
diff --git a/src/resolve/resolved-llmnr.c b/src/resolve/resolved-llmnr.c
index 6a7ff9d245..ed754c3899 100644
--- a/src/resolve/resolved-llmnr.c
+++ b/src/resolve/resolved-llmnr.c
@@ -461,10 +461,8 @@ int manager_llmnr_ipv6_tcp_fd(Manager *m) {
}
r = sd_event_add_io(m->event, &m->llmnr_ipv6_tcp_event_source, m->llmnr_ipv6_tcp_fd, EPOLLIN, on_llmnr_stream, m);
- if (r < 0) {
- r = -errno;
+ if (r < 0)
goto fail;
- }
return m->llmnr_ipv6_tcp_fd;
diff --git a/src/resolve/resolved-mdns.c b/src/resolve/resolved-mdns.c
index 096a4b1fe5..abe63d58c1 100644
--- a/src/resolve/resolved-mdns.c
+++ b/src/resolve/resolved-mdns.c
@@ -275,10 +275,8 @@ int manager_mdns_ipv6_fd(Manager *m) {
}
r = sd_event_add_io(m->event, &m->mdns_ipv6_event_source, m->mdns_ipv6_fd, EPOLLIN, on_mdns_packet, m);
- if (r < 0) {
- r = -errno;
+ if (r < 0)
goto fail;
- }
return m->mdns_ipv6_fd;
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-16 11:49:18 +0000