summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--llmnr-query.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/llmnr-query.c b/llmnr-query.c
index 303961d..de3df26 100644
--- a/llmnr-query.c
+++ b/llmnr-query.c
@@ -1,7 +1,7 @@
/*
* Simple LLMNR query command.
*
- * Copyright (C) 2015 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2015-2016 Tobias Klauser <tklauser@distanz.ch>
*
* This file is part of llmnrd.
*
@@ -67,7 +67,7 @@ static void __noreturn usage_and_exit(int status)
static void __noreturn version_and_exit(void)
{
fprintf(stdout, "llmnr-query %s %s\n"
- "Copyright (C) 2015 Tobias Klauser <tklauser@distanz.ch>\n"
+ "Copyright (C) 2015-2016 Tobias Klauser <tklauser@distanz.ch>\n"
"Licensed under the GNU General Public License, version 2\n",
VERSION_STRING, GIT_VERSION);
exit(EXIT_SUCCESS);
@@ -96,6 +96,7 @@ int main(int argc, char **argv)
uint16_t qtype = LLMNR_QTYPE_A;
bool ipv6 = false;
struct pkt *p;
+ static const int TTL = 255;
while ((c = getopt_long(argc, argv, short_ops, long_opts, NULL)) != -1) {
switch (c) {
@@ -151,6 +152,30 @@ int main(int argc, char **argv)
return -1;
}
+ if (ipv6) {
+ /* RFC 4795, section 2.5 recommends to set TTL to 255 for UDP */
+ if (setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &TTL, sizeof(TTL)) < 0) {
+ log_err("Failed to set IPv6 unicast hops socket option: %s\n", strerror(errno));
+ goto err;
+ }
+
+ if (setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &TTL, sizeof(TTL)) < 0) {
+ log_err("Failed to set IPv6 multicast hops socket option: %s\n", strerror(errno));
+ goto err;
+ }
+ } else {
+ /* RFC 4795, section 2.5 recommends to set TTL to 255 for UDP */
+ if (setsockopt(sock, IPPROTO_IP, IP_TTL, &TTL, sizeof(TTL)) < 0) {
+ log_err("Failed to set IPv4 unicast TTL socket option: %s\n", strerror(errno));
+ goto err;
+ }
+
+ if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_TTL, &TTL, sizeof(TTL)) < 0) {
+ log_err("Failed to set IPv4 multicast TTL socket option: %s\n", strerror(errno));
+ goto err;
+ }
+ }
+
if (iface != NULL) {
unsigned int ifindex = if_nametoindex(iface);