README.udp_relays

IPV6 udp relay:
===============

Name:
udp_redirect_pcap_ipv6.c

Build: 
# gcc udp_redirect_pcap_ipv6.c -lpcap -o udp_redirect_pcap_ipv6

Run:
# ./udp_redirect_pcap_ipv6 &


IPV4 udp relay:
===============
Getting IPV4 broadcast discovery to work

1. Download UDP Broadcast Packet Relay https://www.joachim-breitner.de/udp-broadcast-relay/

git clone https://github.com/nomeata/udp-broadcast-relay.git

2. Do following change

diff --git a/main.c b/main.c
index f3df27b..cd582bf 100644
--- a/main.c
+++ b/main.c
@@ -241,11 +241,13 @@ int main(int argc,char **argv)
                        exit(1);
                }
 
+#if 0
                /* Save the address for later use */
                bcopy(  (struct sockaddr_in *)&reqbuf.ifr_addr,
                        &ifs[maxifs].dstaddr,
                        sizeof(struct sockaddr_in) );
-
+#endif
+        ifs[maxifs].dstaddr.sin_addr.s_addr = inet_addr("255.255.255.255");
                DPRINT("%s: %i / %s\n",
                        reqbuf.ifr_name,
                        ifs[maxifs].ifindex,

3. Set the compiler and then Make

make

4. Start it as follows. Following command makes udp-broadcast relay to listen on port 4123 where we send out ipv4 discovery brodcast packet and then udp-broadcast-relay just forwards it to tap0

./udp-broadcast-relay -f 4123 tap0