From c52782ab32e0f0f46cad66c9c4a52ae30c5b3ec3 Mon Sep 17 00:00:00 2001
From: Jason Rhinelander <jason@imaginary.ca>
Date: Fri, 3 Sep 2021 15:35:09 -0300
Subject: [PATCH] Add IPv6 addr/routing for macos

---
 llarp/apple/PacketTunnelProvider.m | 15 +++++++++++++--
 llarp/apple/context_wrapper.cpp    | 12 ++++++++++--
 llarp/apple/context_wrapper.h      | 11 ++++++++---
 3 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/llarp/apple/PacketTunnelProvider.m b/llarp/apple/PacketTunnelProvider.m
index 38dae4a74..b340e56cb 100644
--- a/llarp/apple/PacketTunnelProvider.m
+++ b/llarp/apple/PacketTunnelProvider.m
@@ -8,6 +8,7 @@
   void* lokinet;
   @public NEPacketTunnelNetworkSettings* settings;
   @public NEIPv4Route* tun_route4;
+  @public NEIPv6Route* tun_route6;
   LLARPDNSTrampoline* dns_tramp;
 }
 
@@ -135,7 +136,7 @@ static void del_default_route(void* ctx) {
   LLARPPacketTunnel* t = (__bridge LLARPPacketTunnel*) ctx;
 
   t->settings.IPv4Settings.includedRoutes = @[t->tun_route4];
-  t->settings.IPv6Settings.includedRoutes = @[]; // No tun_route6 yet.
+  t->settings.IPv6Settings.includedRoutes = @[t->tun_route6];
 
   [t updateNetworkSettings];
 }
@@ -206,6 +207,7 @@ static void del_default_route(void* ctx) {
   dns.matchDomains = @[@""];
   dns.matchDomainsNoSearch = true;
   dns.searchDomains = @[];
+  settings.DNSSettings = dns;
 
   NWHostEndpoint* upstreamdns_ep;
   if (strlen(conf.upstream_dns))
@@ -216,7 +218,16 @@ static void del_default_route(void* ctx) {
   tun_route4 = [[NEIPv4Route alloc] initWithDestinationAddress:ip subnetMask: mask];
   ipv4.includedRoutes = @[tun_route4];
   settings.IPv4Settings = ipv4;
-  settings.DNSSettings = dns;
+
+  NSString* ip6 = [NSString stringWithUTF8String:conf.tunnel_ipv6_ip];
+  NSNumber* ip6_prefix = [NSNumber numberWithUnsignedInt:conf.tunnel_ipv6_prefix];
+  NEIPv6Settings* ipv6 = [[NEIPv6Settings alloc] initWithAddresses:@[ip6]
+                                              networkPrefixLengths:@[ip6_prefix]];
+  tun_route6 = [[NEIPv6Route alloc] initWithDestinationAddress:ip6
+                                           networkPrefixLength:ip6_prefix];
+  ipv6.includedRoutes = @[tun_route6];
+  settings.IPv6Settings = ipv6;
+
   __weak LLARPPacketTunnel* weakSelf = self;
   [self setTunnelNetworkSettings:settings completionHandler:^(NSError* err) {
     if (err) {
diff --git a/llarp/apple/context_wrapper.cpp b/llarp/apple/context_wrapper.cpp
index ce9354540..f2a655778 100644
--- a/llarp/apple/context_wrapper.cpp
+++ b/llarp/apple/context_wrapper.cpp
@@ -60,8 +60,16 @@ llarp_apple_init(llarp_apple_config* appleconf)
     auto mask = llarp::net::TruncateV6(range.netmask_bits).ToString();
     if (addr.size() > 15 || mask.size() > 15)
       throw std::runtime_error{"Unexpected non-IPv4 tunnel range configured"};
-    std::strcpy(appleconf->tunnel_ipv4_ip, addr.c_str());
-    std::strcpy(appleconf->tunnel_ipv4_netmask, mask.c_str());
+    std::strncpy(appleconf->tunnel_ipv4_ip, addr.c_str(), sizeof(appleconf->tunnel_ipv4_ip));
+    std::strncpy(appleconf->tunnel_ipv4_netmask, mask.c_str(), sizeof(appleconf->tunnel_ipv4_netmask));
+
+    // TODO: in the future we want to do this properly with our pubkey (see issue #1705), but that's
+    // going to take a bit more work because we currently can't *get* the (usually) ephemeral pubkey
+    // at this stage of lokinet configuration.  So for now we just stick our IPv4 address into it
+    // until #1705 gets implemented.
+    llarp::huint128_t ipv6{llarp::uint128_t{0xfd2e'6c6f'6b69'0000, llarp::net::TruncateV6(range.addr).h}};
+    std::strncpy(appleconf->tunnel_ipv6_ip, ipv6.ToString().c_str(), sizeof(appleconf->tunnel_ipv6_ip));
+    appleconf->tunnel_ipv6_prefix = 48;
 
     appleconf->upstream_dns[0] = '\0';
     for (auto& upstream : config->dns.m_upstreamDNS)
diff --git a/llarp/apple/context_wrapper.h b/llarp/apple/context_wrapper.h
index 914446741..37c8a5c7b 100644
--- a/llarp/apple/context_wrapper.h
+++ b/llarp/apple/context_wrapper.h
@@ -69,12 +69,17 @@ extern "C"
     const char* default_bootstrap;
     /// llarp_apple_init writes the IP address for the primary tunnel IP address here,
     /// null-terminated.
-    char tunnel_ipv4_ip[16];
+    char tunnel_ipv4_ip[INET_ADDRSTRLEN];
     /// llarp_apple_init writes the netmask of the tunnel address here, null-terminated.
-    char tunnel_ipv4_netmask[16];
+    char tunnel_ipv4_netmask[INET_ADDRSTRLEN];
+    /// Writes the IPv6 address for the tunnel here, null-terminated.
+    char tunnel_ipv6_ip[INET6_ADDRSTRLEN];
+    /// IPv6 address prefix.
+    uint16_t tunnel_ipv6_prefix;
+
     /// The first upstream DNS server's IPv4 address the OS should use when in exit mode.
     /// (Currently on mac in exit mode we only support querying the first such configured server).
-    char upstream_dns[16];
+    char upstream_dns[INET_ADDRSTRLEN];
     uint16_t upstream_dns_port;
 
     /// \defgroup callbacks Callbacks