tlsproxy.c: Add -proxy command line option to use another TLS proxy.

diff --git a/tlsproxy.c b/tlsproxy.c
index a7b4157bf26e3c60d48dc101d16dce16718170b2..39b68df25632a98e153b1a4fbd2119cfe1b3cc50 100644 (file)
--- a/tlsproxy.c
+++ b/tlsproxy.c
@@ -40,6 +40,11 @@
 #define MAX_REQUEST_LINE 4096
 
 
+/* Proxy hostname and port if specified on the command line. */
+static char *use_proxy_host;
+static char *use_proxy_port;
+
+
 static void handle_connection(int socket);
 static int read_http_request(FILE *client_fd, char *request, size_t length);
 static void send_close_bad_request(FILE *client_fd);
@@ -59,19 +64,31 @@ int main(int argc, char **argv) {
     int client_socket, server_socket;
     struct sockaddr_in6 server_in;
 
-    if (2 != argc) {
-        printf("Usage: %s port\n", argv[0]);
+    if (2 != argc && 5 != argc) {
+        printf("Usage: %s [-proxy hostname port] port\n", argv[0]);
         return EXIT_FAILURE;
     }
 
-    port = atoi(argv[1]);
+    port = atoi(argv[5 == argc ? 4 : 1]);
     if (0 >= port || 0xffff < port) {
-        printf("Usage: %s port\n", argv[0]);
+        printf("Usage: %s [-proxy hostname port] port\n", argv[0]);
         printf("\n");
-        printf("Invalid port: %s!\n", argv[1]);
+        printf("Invalid port: %s!\n", argv[5 == argc ? 4 : 1]);
         return EXIT_FAILURE;
     }
 
+    if (5 == argc) {
+        use_proxy_host = strdup(argv[2]);
+        use_proxy_port = strdup(argv[3]);
+        if (NULL == use_proxy_host || NULL == use_proxy_port) {
+            perror("strdup()");
+            return EXIT_FAILURE;
+        }
+#ifdef DEBUG
+        printf("Using proxy: %s:%s.\n", use_proxy_host, use_proxy_port);
+#endif
+    }
+
     server_socket = socket(PF_INET6, SOCK_STREAM, 0);
     if (-1 == server_socket) {
         perror("socket()");
@@ -166,7 +183,13 @@ static void handle_connection(int client_socket) {
     printf("  %s:%s (HTTP 1.%d)\n", host, port, version_minor);
 #endif
 
-    server_socket = connect_to_host(host, port);
+    /* Connect to proxy server or directly to server. */
+    if (NULL != use_proxy_host && NULL != use_proxy_port) {
+        server_socket = connect_to_host(use_proxy_host, use_proxy_port);
+    } else {
+        server_socket = connect_to_host(host, port);
+    }
+
     if (-1 == server_socket) {
         send_close_forwarding_failure(client_fd);
         return;
@@ -177,6 +200,39 @@ static void handle_connection(int client_socket) {
         return;
     }
 
+    /* Connect to proxy if requested (command line option). */
+    if (NULL != use_proxy_host && NULL != use_proxy_port) {
+        fprintf(server_fd, "CONNECT %s:%s HTTP/1.0\r\n", host, port);
+        fprintf(server_fd, "\r\n");
+
+        /* Read response line from proxy server. */
+        result = read_http_request(server_fd, buffer, sizeof(buffer));
+        if (result == -1) {
+            /* Read error. */
+            send_close_forwarding_failure(client_fd);
+            return;
+        } else if (result == -2) {
+            /* EOF */
+            fclose(server_fd);
+            send_close_forwarding_failure(client_fd);
+            return;
+        }
+
+        /* Check response of proxy server. */
+        if (0 != strncmp(buffer, "HTTP/1.0 200", 12)) {
+#ifdef DEBUG
+            printf("  bad proxy response\n");
+#endif
+            fclose(server_fd);
+            send_close_forwarding_failure(client_fd);
+            return;
+        }
+    }
+
+#ifdef DEBUG
+    printf("  connection to server established\n");
+#endif
+
     /* We've established a connection, tell the client. */
     fprintf(client_fd, "HTTP/1.0 200 Connection established\r\n");
     fprintf(client_fd, "\r\n");