5 files changed, 105 insertions, 6 deletions

diff --git a/src/main_gui.cpp b/src/main_gui.cpp
index 90a6050..bef8503 100644
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -138,6 +138,7 @@ static void PrintUsage()
     printf("Network:\n");
     printf("  /port=N                    (P2P listen port, default 8433)\n");
     printf("  /socks=HOST:PORT           (SOCKS5 proxy for outbound Nostr and .btf relay dials)\n");
+    printf("  /tor[=HOST:PORT]           (Tor mode; default SOCKS5 proxy is 127.0.0.1:9050)\n");
     printf("  /btfseed=ADDRESS:ENCHEX    (extra bootstrap peer, repeatable)\n");
     printf("\n");
     printf("Wallet:\n");
@@ -285,16 +286,35 @@ static void ParseStartupArguments(int argc, char* argv[])
     if (!announceRelay.empty())
         strBtfAnnounceRelay = announceRelay;
 
-    string socksProxy = argval2(argc, argv, "/socks", "-socks");
-    if (!socksProxy.empty())
+    bool fTorMode = arg(argc, argv, "/tor") || arg(argc, argv, "-tor");
+    if (fTorMode)
     {
+        string socksProxy = argval2(argc, argv, "/socks", "-socks");
+        if (!socksProxy.empty())
+            fprintf(stderr, "Warning: /tor takes precedence over /socks=%s\n",
+                    socksProxy.c_str());
+
+        string torProxy = argval2(argc, argv, "/tor", "-tor");
         string err;
-        if (!BtfSetSocks5Proxy(socksProxy, err))
-            fprintf(stderr, "Ignoring /socks=%s: %s\n", socksProxy.c_str(), err.c_str());
+        if (!BtfEnableTorProxy(torProxy, err))
+            fprintf(stderr, "Ignoring /tor=%s: %s\n", torProxy.c_str(), err.c_str());
         else
-            fprintf(stderr, "SOCKS5 proxy enabled for outbound discovery/relay dials: %s\n",
+            fprintf(stderr, "Tor mode enabled through SOCKS5 proxy %s\n",
                     BtfSocks5ProxyName().c_str());
     }
+    else
+    {
+        string socksProxy = argval2(argc, argv, "/socks", "-socks");
+        if (!socksProxy.empty())
+        {
+            string err;
+            if (!BtfSetSocks5Proxy(socksProxy, err))
+                fprintf(stderr, "Ignoring /socks=%s: %s\n", socksProxy.c_str(), err.c_str());
+            else
+                fprintf(stderr, "SOCKS5 proxy enabled for outbound discovery/relay dials: %s\n",
+                        BtfSocks5ProxyName().c_str());
+        }
+    }
 
     // /btfseed=ADDRESS:ENCHEX -- extra bootstrap peers, repeatable. Useful for
     // testing the seed path and for private networks that ship no compiled list.
diff --git a/src/proxy.cpp b/src/proxy.cpp
index d7dc324..7d30911 100644
--- a/src/proxy.cpp
+++ b/src/proxy.cpp
@@ -9,8 +9,10 @@
 
 static CCriticalSection cs_socks5;
 static bool g_fSocks5Proxy = false;
+static bool g_fTorProxy = false;
 static std::string g_socks5Host;
 static unsigned short g_socks5Port = 0;
+static const char* DEFAULT_TOR_SOCKS5_PROXY = "127.0.0.1:9050";
 
 static void SetSocketTimeout(SOCKET s, int nTimeoutSecs)
 {
@@ -67,6 +69,24 @@ static bool ValidProxyIpv6HostChar(char c)
     return isxdigit((unsigned char)c) || c == ':' || c == '.';
 }
 
+static std::string LowerProxyHost(std::string host)
+{
+    if (!host.empty() && host[host.size() - 1] == '.')
+        host.erase(host.size() - 1);
+    for (size_t i = 0; i < host.size(); i++)
+        host[i] = (char)tolower((unsigned char)host[i]);
+    return host;
+}
+
+bool BtfIsTorOnionHost(const std::string& host)
+{
+    std::string lower = LowerProxyHost(host);
+    static const char* suffix = ".onion";
+    size_t suffixLen = strlen(suffix);
+    return lower.size() > suffixLen &&
+           lower.compare(lower.size() - suffixLen, suffixLen, suffix) == 0;
+}
+
 static bool ParsePort(const std::string& port, unsigned short& portOut,
                       std::string& errOut)
 {
@@ -176,7 +196,8 @@ bool BtfParseSocks5Proxy(const std::string& spec, std::string& hostOut,
     return true;
 }
 
-bool BtfSetSocks5Proxy(const std::string& spec, std::string& errOut)
+static bool SetSocks5Proxy(const std::string& spec, bool fTorMode,
+                           std::string& errOut)
 {
     std::string host;
     unsigned short port = 0;
@@ -187,15 +208,27 @@ bool BtfSetSocks5Proxy(const std::string& spec, std::string& errOut)
         g_socks5Host = host;
         g_socks5Port = port;
         g_fSocks5Proxy = true;
+        g_fTorProxy = fTorMode;
     }
     return true;
 }
 
+bool BtfSetSocks5Proxy(const std::string& spec, std::string& errOut)
+{
+    return SetSocks5Proxy(spec, false, errOut);
+}
+
+bool BtfEnableTorProxy(const std::string& spec, std::string& errOut)
+{
+    return SetSocks5Proxy(spec.empty() ? DEFAULT_TOR_SOCKS5_PROXY : spec, true, errOut);
+}
+
 void BtfClearSocks5Proxy()
 {
     CRITICAL_BLOCK(cs_socks5)
     {
         g_fSocks5Proxy = false;
+        g_fTorProxy = false;
         g_socks5Host.clear();
         g_socks5Port = 0;
     }
@@ -208,6 +241,13 @@ bool BtfSocks5ProxyEnabled()
     return false;
 }
 
+bool BtfTorProxyEnabled()
+{
+    CRITICAL_BLOCK(cs_socks5)
+        return g_fSocks5Proxy && g_fTorProxy;
+    return false;
+}
+
 std::string BtfSocks5ProxyName()
 {
     CRITICAL_BLOCK(cs_socks5)
@@ -315,7 +355,15 @@ SOCKET BtfConnectSocket(const std::string& destHost, unsigned short destPort,
     }
 
     if (!fProxy)
+    {
+        if (BtfIsTorOnionHost(destHost))
+        {
+            error("Refusing direct .onion connection to %s:%u; use /tor or /socks\n",
+                  destHost.c_str(), (unsigned)destPort);
+            return INVALID_SOCKET;
+        }
         return ConnectDirect(destHost, destPort, nSockSite, nTimeoutSecs);
+    }
 
     SOCKET s = ConnectDirect(proxyHost, proxyPort, nSockSite, nTimeoutSecs);
     if (s == INVALID_SOCKET)
diff --git a/src/proxy.h b/src/proxy.h
index b5e69c8..6429cf2 100644
--- a/src/proxy.h
+++ b/src/proxy.h
@@ -21,8 +21,11 @@
 bool BtfParseSocks5Proxy(const std::string& spec, std::string& hostOut,
                          unsigned short& portOut, std::string& errOut);
 bool BtfSetSocks5Proxy(const std::string& spec, std::string& errOut);
+bool BtfEnableTorProxy(const std::string& spec, std::string& errOut);
 void BtfClearSocks5Proxy();
 bool BtfSocks5ProxyEnabled();
+bool BtfTorProxyEnabled();
+bool BtfIsTorOnionHost(const std::string& host);
 std::string BtfSocks5ProxyName();
 
 SOCKET BtfConnectSocket(const std::string& destHost, unsigned short destPort,
diff --git a/src/readme.txt b/src/readme.txt
index 1fa77df..794fe20 100644
--- a/src/readme.txt
+++ b/src/readme.txt
@@ -46,6 +46,9 @@ Command-line options (in addition to the original ones)
                  route outbound Nostr and .btf rendezvous dials through a
                  SOCKS5 proxy, e.g. /socks=127.0.0.1:9050 for local Tor
                  or /socks=[::1]:9050 for an IPv6 loopback proxy
+  /tor[=HOST:PORT]
+                 Tor mode for outbound Nostr and .btf rendezvous dials;
+                 defaults to the local Tor SOCKS5 proxy at 127.0.0.1:9050
   /solomine      mine without requiring a connected peer (local testing)
   /operator      operator mode (run pool server)
   /participant=ADDR
diff --git a/src/selftest.cpp b/src/selftest.cpp
index aa4e528..cca5335 100644
--- a/src/selftest.cpp
+++ b/src/selftest.cpp
@@ -1474,6 +1474,11 @@ static int RunSocks5ProxySelfTest()
                    "rejects overflowing port") ? 0 : 1;
     nFail += Check(!BtfParseSocks5Proxy("user:pass@localhost:9050", host, port, err),
                    "rejects unsupported authenticated proxy syntax") ? 0 : 1;
+    nFail += Check(BtfIsTorOnionHost("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd.onion") &&
+                   BtfIsTorOnionHost("Relay.Example.ONION.") &&
+                   !BtfIsTorOnionHost("relay.example") &&
+                   !BtfIsTorOnionHost(".onion"),
+                   "detects .onion hosts without accepting lookalikes") ? 0 : 1;
 
     BtfClearSocks5Proxy();
     nFail += Check(!BtfSocks5ProxyEnabled(), "starts disabled after clear") ? 0 : 1;
@@ -1490,6 +1495,26 @@ static int RunSocks5ProxySelfTest()
                    "enables bracketed IPv6 proxy endpoint") ? 0 : 1;
     BtfClearSocks5Proxy();
 
+    nFail += Check(BtfEnableTorProxy("", err) &&
+                   BtfSocks5ProxyEnabled() &&
+                   BtfTorProxyEnabled() &&
+                   BtfSocks5ProxyName() == "127.0.0.1:9050",
+                   "enables Tor mode on the default local SOCKS5 endpoint") ? 0 : 1;
+    BtfClearSocks5Proxy();
+
+    nFail += Check(BtfEnableTorProxy("[::1]:9050", err) &&
+                   BtfSocks5ProxyEnabled() &&
+                   BtfTorProxyEnabled() &&
+                   BtfSocks5ProxyName() == "[::1]:9050",
+                   "enables Tor mode on a custom IPv6 endpoint") ? 0 : 1;
+    BtfClearSocks5Proxy();
+
+    nFail += Check(BtfSetSocks5Proxy("127.0.0.1:9051", err) &&
+                   BtfSocks5ProxyEnabled() &&
+                   !BtfTorProxyEnabled(),
+                   "plain SOCKS5 mode is distinct from Tor mode") ? 0 : 1;
+    BtfClearSocks5Proxy();
+
     std::string handshakeErr;
     bool fHandshakeOk = RunSocks5HandshakeProbe(handshakeErr);
     nFail += Check(fHandshakeOk, handshakeErr.empty() ?