tlsproxy.c: Use getopt() to parse command line arguments.

[tlsproxy/tlsproxy.git] / tlsproxy.c

diff --git a/tlsproxy.c b/tlsproxy.c
index a7b4157bf26e3c60d48dc101d16dce16718170b2..2d16465c58678a5bb1139d4761dece8d7910a939 100644 (file)
--- a/tlsproxy.c
+++ b/tlsproxy.c
@@ -40,6 +40,13 @@
 #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 parse_arguments(int argc, char **argv);
+static void print_usage(const char *argv);
+
 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);
@@ -59,16 +66,12 @@ 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]);
-        return EXIT_FAILURE;
-    }
+    parse_arguments(argc, argv);
 
-    port = atoi(argv[1]);
+    port = atoi(argv[argc - 1]);
     if (0 >= port || 0xffff < port) {
-        printf("Usage: %s port\n", argv[0]);
-        printf("\n");
-        printf("Invalid port: %s!\n", argv[1]);
+        print_usage(argv[0]);
+        fprintf(stderr, "\ninvalid port");
         return EXIT_FAILURE;
     }
 
@@ -103,6 +106,14 @@ int main(int argc, char **argv) {
         return EXIT_FAILURE;
     }
 
+#ifdef DEBUG
+    printf("Listening for connections on port %d.\n", port);
+
+    if (NULL != use_proxy_host && NULL != use_proxy_port) {
+        printf("Using proxy: %s:%s.\n", use_proxy_host, use_proxy_port);
+    }
+#endif
+
     for (;;) {
         /* Accept new connection. */
         client_socket = accept(server_socket, NULL, NULL);
@@ -117,6 +128,59 @@ int main(int argc, char **argv) {
     return EXIT_SUCCESS;
 }
 
+static void parse_arguments(int argc, char **argv) {
+    int option;
+
+    while (-1 != (option = getopt(argc, argv, "p:h?"))) {
+        switch (option) {
+            case 'p': {
+                char *position;
+
+                /* -p must have the format host:port. */
+                if (NULL == (position = strchr(optarg, ':'))
+                        || position == optarg
+                        || 0 == strlen(position + 1)
+                        || 0 >= atoi(position + 1)
+                        || 0xffff < atoi(position + 1)) {
+                    fprintf(stderr, "-p host:port\n");
+                    exit(EXIT_FAILURE);
+                }
+
+                use_proxy_host = malloc((size_t)(position - optarg) + 1);
+                if (NULL == use_proxy_host) {
+                    perror("malloc()");
+                    exit(EXIT_FAILURE);
+                }
+                memcpy(use_proxy_host, optarg, (size_t)(position - optarg));
+                use_proxy_host[position - optarg] = '\0';
+
+                use_proxy_port = malloc(strlen(position + 1) + 1);
+                if (NULL == use_proxy_port) {
+                    perror("malloc()");
+                    exit(EXIT_FAILURE);
+                }
+                strcpy(use_proxy_port, position + 1);
+
+                break;
+            }
+            case 'h':
+            default: /* '?' */
+                print_usage(argv[0]);
+                exit(EXIT_FAILURE);
+        }
+    }
+
+    if (optind >= argc) {
+        print_usage(argv[0]);
+        exit(EXIT_FAILURE);
+    }
+}
+static void print_usage(const char *argv) {
+    fprintf(stderr, "Usage: %s [-p host:port] port\n", argv);
+    fprintf(stderr, "\n");
+    fprintf(stderr, "-p proxy hostname and port\n");
+}
+
 static void handle_connection(int client_socket) {
     int server_socket;
     FILE *client_fd, *server_fd;
@@ -166,7 +230,13 @@ 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 +247,39 @@ 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");