diff options
| -rw-r--r-- | llmnr-query.c | 29 |
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); |