Add the ability to punch through multiple NATs in some situations

miss/tracer.cpp

@@ -1,5 +1,6 @@
 #define WIN32_LEAN_AND_MEAN
 #define _WINSOCK_DEPRECATED_NO_WARNINGS
+#define _CRT_SECURE_NO_WARNINGS
 #include <Windows.h>
 
 #include <WinSock2.h>
@@ -8,6 +9,131 @@
 #include <icmpapi.h>
 
 #include <stdio.h>
+#include <stdlib.h>
+
+#define MINIUPNP_STATICLIB
+#include <miniupnpc/miniupnpc.h>
+
+static const char* k_SsdpSearchFormatString =
+    "M-SEARCH * HTTP/1.1\r\n"
+    "HOST: %s:1900\r\n"
+    "ST: ssdp:all\r\n"
+    "MAN: \"ssdp:discover\"\r\n"
+    "MX: 5\r\n"
+    "\r\n";
+
+struct UPNPDev* getUPnPDevicesByAddress(IN_ADDR address)
+{
+    SOCKET s;
+    SOCKADDR_IN connAddr;
+    char searchBuffer[512];
+    int chars;
+
+    s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    if (s == INVALID_SOCKET) {
+        printf("socket() failed: %d\n", WSAGetLastError());
+        return nullptr;
+    }
+
+    connAddr = {};
+    connAddr.sin_family = AF_INET;
+    connAddr.sin_port = htons(1900);
+    connAddr.sin_addr = address;
+
+    // Use connect() to ensure we don't get responses from other devices
+    if (connect(s, (struct sockaddr*)&connAddr, sizeof(connAddr)) == SOCKET_ERROR) {
+        printf("connect() failed: %d\n", WSAGetLastError());
+        closesocket(s);
+        return nullptr;
+    }
+
+    // Send the first search message with HOST set properly
+    chars = snprintf(searchBuffer, ARRAYSIZE(searchBuffer), k_SsdpSearchFormatString, inet_ntoa(address));
+    if (send(s, searchBuffer, chars, 0) == SOCKET_ERROR) {
+        printf("send() failed: %d\n", WSAGetLastError());
+        closesocket(s);
+        return nullptr;
+    }
+
+    // Send another search message with HOST set to 239.255.255.250 to avoid issues
+    // on routers that explicitly check for that HOST value
+    chars = snprintf(searchBuffer, ARRAYSIZE(searchBuffer), k_SsdpSearchFormatString, "239.255.255.250");
+    if (send(s, searchBuffer, chars, 0) == SOCKET_ERROR) {
+        printf("send() failed: %d\n", WSAGetLastError());
+        closesocket(s);
+        return nullptr;
+    }
+
+    Sleep(5000);
+
+    // Switch to non-blocking mode to read the responses
+    u_long mode = 1;
+    ioctlsocket(s, FIONBIO, &mode);
+
+    char responseBuffer[1024];
+    struct UPNPDev* deviceList = nullptr;
+    for (;;) {
+        int bytesRead = recv(s, responseBuffer, sizeof(responseBuffer) - 1, 0);
+        if (bytesRead == SOCKET_ERROR) {
+            if (WSAGetLastError() != WSAEWOULDBLOCK) {
+                printf("recv() failed: %d\n", WSAGetLastError());
+            }
+            break;
+        }
+
+        // Null-terminate the buffer
+        responseBuffer[bytesRead] = 0;
+
+        // Parse the first status line:
+        // HTTP/1.1 200 OK
+        char* protocol = strtok(responseBuffer, " ");
+        char* statusCodeStr = strtok(nullptr, " ");
+        char* statusMessage = strtok(nullptr, "\r");
+        if (_stricmp(protocol, "HTTP/1.0") && _stricmp(protocol, "HTTP/1.1")) {
+            printf("Unexpected protocol: %s\n", protocol);
+            continue;
+        }
+        if (atoi(statusCodeStr) != 200) {
+            printf("Unexpected status: %s %s\n", statusCodeStr, statusMessage);
+            continue;
+        }
+
+        // Parse the header options
+        // SERVER: FreeBSD/11.2-RELEASE-p2 UPnP/1.1 MiniUPnPd/2.0\r\n
+        char* location = nullptr;
+        char* st = nullptr;
+        while (char* headerName = strtok(nullptr, "\r\n:")) {
+            char* headerValue = strtok(nullptr, "\r");
+
+            // Skip leading spaces
+            while (*headerValue == ' ') headerValue++;
+
+            if (!_stricmp(headerName, "LOCATION")) {
+                location = headerValue;
+            }
+            else if (!_stricmp(headerName, "ST")) {
+                st = headerValue;
+            }
+        }
+
+        if (!location || location[0] == 0 || !st || st[0] == 0) {
+            printf("Required value missing: \"%s\" \"%s\"\n", location, st);
+            continue;
+        }
+
+        struct UPNPDev* newDev = (struct UPNPDev*)malloc(sizeof(*newDev) + strlen(location) + strlen(st) + 2);
+        
+        newDev->pNext = deviceList;
+        newDev->usn = &newDev->buffer[0]; newDev->buffer[0] = 0;
+        newDev->descURL = strcpy(newDev->usn + strlen(newDev->usn) + 1, location);
+        newDev->st = strcpy(newDev->descURL + strlen(newDev->descURL) + 1, st);
+        newDev->scope_id = 0; // IPv6 only
+
+        deviceList = newDev;
+    }
+
+    return deviceList;
+}
 
 bool getHopsIP4(IN_ADDR* hopAddress, int* hopAddressCount)
 {
@@ -64,12 +190,13 @@ bool getHopsIP4(IN_ADDR* hopAddress, int* hopAddressCount)
         else {
             // Bail on anything else
             printf("Hop %d: %s (error %d)\n", ttl, inet_ntoa(*(IN_ADDR*)&replies[0].Address), replies[0].Status);
-            *hopAddressCount = ttl - 1;
             break;
         }
     }
 
     IcmpCloseHandle(icmpFile);
 
+    *hopAddressCount = ttl - 1;
     return true;
-}
+}
+