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resolved: set LLMNR TCP and UDP TTLs to the values suggested by the RFC

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This commit is contained in:
Lennart Poettering 2014-07-29 23:51:34 +02:00
parent 088b6ba264
commit bf3f1271e2
2 changed files with 11 additions and 7 deletions
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2
src/resolve/resolved-dns-scope.c
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@ -254,7 +254,7 @@ int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *add
}
if (s->protocol == DNS_PROTOCOL_LLMNR) {
/* RFC 4795, section 2.5 suggests the TTL to be set to 1 */
/* RFC 4795, section 2.5 requires the TTL to be set to 1 */
if (sa.sa.sa_family == AF_INET) {
r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));

16
src/resolve/resolved-manager.c
View file

@ -1024,7 +1024,7 @@ int manager_llmnr_ipv4_udp_fd(Manager *m) {
.in.sin_family = AF_INET,
.in.sin_port = htobe16(5355),
};
static const int one = 1, pmtu = IP_PMTUDISC_DONT;
static const int one = 1, pmtu = IP_PMTUDISC_DONT, ttl = 255;
int r;
assert(m);
@ -1036,13 +1036,14 @@ int manager_llmnr_ipv4_udp_fd(Manager *m) {
if (m->llmnr_ipv4_udp_fd < 0)
return -errno;
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &one, sizeof(one));
r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
@ -1101,7 +1102,7 @@ int manager_llmnr_ipv6_udp_fd(Manager *m) {
.in6.sin6_family = AF_INET6,
.in6.sin6_port = htobe16(5355),
};
static const int one = 1;
static const int one = 1, ttl = 255;
int r;
assert(m);
@ -1113,13 +1114,14 @@ int manager_llmnr_ipv6_udp_fd(Manager *m) {
if (m->llmnr_ipv6_udp_fd < 0)
return -errno;
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
}
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &one, sizeof(one));
/* RFC 4795, section 2.5 recommends setting the TTL of UDP packets to 255. */
r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl));
if (r < 0) {
r = -errno;
goto fail;
@ -1243,6 +1245,7 @@ int manager_llmnr_ipv4_tcp_fd(Manager *m) {
if (m->llmnr_ipv4_tcp_fd < 0)
return -errno;
/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
r = setsockopt(m->llmnr_ipv4_tcp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
if (r < 0) {
r = -errno;
@ -1314,6 +1317,7 @@ int manager_llmnr_ipv6_tcp_fd(Manager *m) {
if (m->llmnr_ipv6_tcp_fd < 0)
return -errno;
/* RFC 4795, section 2.5. requires setting the TTL of TCP streams to 1 */
r = setsockopt(m->llmnr_ipv6_tcp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one));
if (r < 0) {
r = -errno;