From 16e1b731f69284b0c9992ac755f9278de4cdd5cc Mon Sep 17 00:00:00 2001
From: Chris Hellberg <chris@chrishellberg.com>
Date: Tue, 28 Dec 2021 03:14:05 +0000
Subject: [PATCH] Linux server interfaces populated with V6 addresses

---
 src/iodine.c  |  2 +-
 src/iodined.c | 16 +++++++++++-----
 src/tun.c     | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/src/iodine.c b/src/iodine.c
index 3f81495..2059779 100644
--- a/src/iodine.c
+++ b/src/iodine.c
@@ -372,7 +372,7 @@ int main(int argc, char **argv)
 	fprintf(stderr, "Sending DNS queries for %s to %s\n",
 		topdomain, format_addr(&nameservaddr, nameservaddr_len));
 
-	if (client_handshake(dns_fd, raw_mode, autodetect_frag_size, max_downstream_frag_size)) {
+	if (client_handshake(dns_fd, raw_mode, autodetect_frag_size, max_downstream_frag_size, forward_v6)) {
 		retval = 1;
 		goto cleanup2;
 	}
diff --git a/src/iodined.c b/src/iodined.c
index ff405a5..0a02632 100644
--- a/src/iodined.c
+++ b/src/iodined.c
@@ -2437,7 +2437,7 @@ main(int argc, char **argv)
 	srand(time(NULL));
 	fw_query_init();
 
-	while ((choice = getopt(argc, argv, "46vcsfhDu:t:d:m:l:L:p:n:b:P:z:F:i:")) != -1) {
+	while ((choice = getopt(argc, argv, "46vcsfhDuS:t:d:m:l:L:p:n:b:P:z:F:i:")) != -1) {
 		switch(choice) {
 		case '4':
 			addrfamily = AF_INET;
@@ -2678,11 +2678,17 @@ main(int argc, char **argv)
 	}
 	if (!skipipconfig) {
 		const char *other_ip = users_get_first_ip();
-		if (tun_setip(argv[0], other_ip, netmask, forward_v6) != 0 || tun_setmtu(mtu) != 0) {
-			retval = 1;
+		if (tun_setip(argv[0], other_ip, netmask, forward_v6) || tun_setmtu(mtu) != 0) {
+                        retval = 1; 
 			free((void*) other_ip);
-			goto cleanup;
-		}
+                        goto cleanup;
+			
+	        }
+		if ((mtu < 1280) && (forward_v6)) {
+                                warnx("Interface mtu of %d below the 1280 threshold needed for IPv6 tunneling.\n", mtu);         
+                                warnx("Proceeding without IPv6 tunneling\n");         
+		} 
+
 		free((void*) other_ip);
 	}
 
diff --git a/src/tun.c b/src/tun.c
index 804fad7..7c20404 100644
--- a/src/tun.c
+++ b/src/tun.c
@@ -595,9 +595,11 @@ int
 tun_setip(const char *ip, const char *other_ip, int netbits, int forward_v6)
 {
 	char cmdline[512];
+	char v6_cmdline[512];
 	int netmask;
 	struct in_addr net;
 	int i;
+	int v6_r;
 #ifndef LINUX
 	int r;
 #endif
@@ -630,6 +632,18 @@ tun_setip(const char *ip, const char *other_ip, int netbits, int forward_v6)
 # else
 	display_ip = ip;
 # endif
+        fprintf(stderr, "Setting IPv6 of %s to ::%s\n", if_name, ip);
+
+        snprintf(v6_cmdline, sizeof(cmdline),
+                        IFCONFIGPATH "ifconfig %s inet6 add ::%s/64",
+                        if_name,
+                        display_ip);
+
+	v6_r = system(v6_cmdline);
+
+        if (v6_r != 0) {
+            return v6_r;
+        } 
 	snprintf(cmdline, sizeof(cmdline),
 			IFCONFIGPATH "ifconfig %s %s %s netmask %s",
 			if_name,