From fc050b3a09fd652b84b19731e543b91144788e35 Mon Sep 17 00:00:00 2001
From: Jeff Becker <jeff@lokinet.io>
Date: Sat, 20 May 2023 18:18:40 -0400
Subject: [PATCH] fix issue #2179

when setting libunbound's upstream dns, we need to not pass in the square braces of an ipv6 address.
we also net udp handles have ipv6 address for the local ip.
---
 llarp/dns/server.cpp    |  5 +----
 llarp/ev/libuv.cpp      |  7 +++++--
 llarp/net/sock_addr.cpp | 26 +++++++++++---------------
 llarp/net/sock_addr.hpp |  2 +-
 4 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/llarp/dns/server.cpp b/llarp/dns/server.cpp
index ef1c01c03..10ed94476 100644
--- a/llarp/dns/server.cpp
+++ b/llarp/dns/server.cpp
@@ -177,10 +177,7 @@ namespace llarp::dns
       void
       AddUpstreamResolver(const SockAddr& dns)
       {
-        std::string str = dns.hostString();
-
-        if (const auto port = dns.getPort(); port != 53)
-          fmt::format_to(std::back_inserter(str), "@{}", port);
+        std::string str = fmt::format("{}@{}", dns.hostString(false), dns.getPort());
 
         if (auto err = ub_ctx_set_fwd(m_ctx, str.c_str()))
         {
diff --git a/llarp/ev/libuv.cpp b/llarp/ev/libuv.cpp
index 75e370522..ce9e573ed 100644
--- a/llarp/ev/libuv.cpp
+++ b/llarp/ev/libuv.cpp
@@ -75,8 +75,11 @@ namespace llarp::uv
     std::optional<SockAddr>
     LocalAddr() const override
     {
-      auto addr = handle->sock<uvw::IPv4>();
-      return SockAddr{addr.ip, huint16_t{static_cast<uint16_t>(addr.port)}};
+      if (auto addr = handle->sock<uvw::IPv4>(); not addr.ip.empty())
+        return SockAddr{addr.ip, huint16_t{static_cast<uint16_t>(addr.port)}};
+      if (auto addr = handle->sock<uvw::IPv6>(); not addr.ip.empty())
+        return SockAddr{addr.ip, huint16_t{static_cast<uint16_t>(addr.port)}};
+      return std::nullopt;
     }
 
     std::optional<int>
diff --git a/llarp/net/sock_addr.cpp b/llarp/net/sock_addr.cpp
index 8fdf457f1..84ccdc6e1 100644
--- a/llarp/net/sock_addr.cpp
+++ b/llarp/net/sock_addr.cpp
@@ -290,25 +290,21 @@ namespace llarp
   }
 
   std::string
-  SockAddr::hostString() const
+  SockAddr::hostString(bool add_braces) const
   {
-    std::string str;
-    char buf[INET6_ADDRSTRLEN] = {0x0};
+    std::array<char, 128> buf{};
     if (isIPv4())
     {
-      // handle IPv4 mapped addrs
-      inet_ntop(AF_INET, &m_addr4.sin_addr.s_addr, buf, sizeof(buf));
-      str = buf;
+      // IPv4 mapped addrs
+      inet_ntop(AF_INET, &m_addr4.sin_addr.s_addr, buf.data(), buf.size());
+      return buf.data();
     }
-    else
-    {
-      inet_ntop(AF_INET6, &m_addr.sin6_addr.s6_addr, buf, sizeof(buf));
-      str.reserve(std::strlen(buf) + 2);
-      str.append("[");
-      str.append(buf);
-      str.append("]");
-    }
-    return str;
+
+    inet_ntop(AF_INET6, &m_addr.sin6_addr.s6_addr, buf.data(), buf.size());
+    if (not add_braces)
+      return buf.data();
+
+    return fmt::format("[{}]", buf.data());
   }
 
   bool
diff --git a/llarp/net/sock_addr.hpp b/llarp/net/sock_addr.hpp
index 7634c6e23..448a8c6d5 100644
--- a/llarp/net/sock_addr.hpp
+++ b/llarp/net/sock_addr.hpp
@@ -87,7 +87,7 @@ namespace llarp
     ToString() const;
 
     std::string
-    hostString() const;
+    hostString(bool add_braces = true) const;
 
     inline int
     Family() const