config: Move relay port parsing into the relay module

This commit:
* creates feature/relay/relay_config.[ch],
* moves relay port parsing into them,
* exposes some code from src/app/config.c
  (we'll refactor it later in 29211), and
* adds thin wrappers to make the moved code compile.

No functional changes: the moved code is still enabled,
even if the relay module is disabled.

Part of 32213.

1 files changed, 222 insertions, 0 deletions

diff --git a/src/feature/relay/relay_config.c b/src/feature/relay/relay_config.c
new file mode 100644
index 0000000000..6ec802fc5a
--- /dev/null
+++ b/src/feature/relay/relay_config.c
@@ -0,0 +1,222 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file relay_config.c
+ * @brief Code to interpret the user's configuration of Tor's relay module.
+ **/
+
+#include "orconfig.h"
+#include "feature/relay/relay_config.h"
+
+#include "lib/encoding/confline.h"
+#include "lib/confmgt/confmgt.h"
+
+#include "lib/container/smartlist.h"
+#include "lib/process/setuid.h"
+
+/* Required for dirinfo_type_t in or_options_t */
+#include "core/or/or.h"
+#include "app/config/config.h"
+
+#include "core/mainloop/connection.h"
+#include "core/or/port_cfg_st.h"
+
+#include "feature/relay/dns.h"
+#include "feature/relay/ext_orport.h"
+#include "feature/relay/routermode.h"
+
+/** Given a list of <b>port_cfg_t</b> in <b>ports</b>, check them for internal
+ * consistency and warn as appropriate.  On Unix-based OSes, set
+ * *<b>n_low_ports_out</b> to the number of sub-1024 ports we will be
+ * binding, and warn if we may be unable to re-bind after hibernation. */
+static int
+check_server_ports(const smartlist_t *ports,
+                   const or_options_t *options,
+                   int *n_low_ports_out)
+{
+  if (BUG(!ports))
+    return -1;
+
+  if (BUG(!options))
+    return -1;
+
+  if (BUG(!n_low_ports_out))
+    return -1;
+
+  int n_orport_advertised = 0;
+  int n_orport_advertised_ipv4 = 0;
+  int n_orport_listeners = 0;
+  int n_dirport_advertised = 0;
+  int n_dirport_listeners = 0;
+  int n_low_port = 0;
+  int r = 0;
+
+  SMARTLIST_FOREACH_BEGIN(ports, const port_cfg_t *, port) {
+    if (port->type == CONN_TYPE_DIR_LISTENER) {
+      if (! port->server_cfg.no_advertise)
+        ++n_dirport_advertised;
+      if (! port->server_cfg.no_listen)
+        ++n_dirport_listeners;
+    } else if (port->type == CONN_TYPE_OR_LISTENER) {
+      if (! port->server_cfg.no_advertise) {
+        ++n_orport_advertised;
+        if (port_binds_ipv4(port))
+          ++n_orport_advertised_ipv4;
+      }
+      if (! port->server_cfg.no_listen)
+        ++n_orport_listeners;
+    } else {
+      continue;
+    }
+#ifndef _WIN32
+    if (!port->server_cfg.no_listen && port->port < 1024)
+      ++n_low_port;
+#endif
+  } SMARTLIST_FOREACH_END(port);
+
+  if (n_orport_advertised && !n_orport_listeners) {
+    log_warn(LD_CONFIG, "We are advertising an ORPort, but not actually "
+             "listening on one.");
+    r = -1;
+  }
+  if (n_orport_listeners && !n_orport_advertised) {
+    log_warn(LD_CONFIG, "We are listening on an ORPort, but not advertising "
+             "any ORPorts. This will keep us from building a %s "
+             "descriptor, and make us impossible to use.",
+             options->BridgeRelay ? "bridge" : "router");
+    r = -1;
+  }
+  if (n_dirport_advertised && !n_dirport_listeners) {
+    log_warn(LD_CONFIG, "We are advertising a DirPort, but not actually "
+             "listening on one.");
+    r = -1;
+  }
+  if (n_dirport_advertised > 1) {
+    log_warn(LD_CONFIG, "Can't advertise more than one DirPort.");
+    r = -1;
+  }
+  if (n_orport_advertised && !n_orport_advertised_ipv4 &&
+      !options->BridgeRelay) {
+    log_warn(LD_CONFIG, "Configured public relay to listen only on an IPv6 "
+             "address. Tor needs to listen on an IPv4 address too.");
+    r = -1;
+  }
+
+  if (n_low_port && options->AccountingMax &&
+      (!have_capability_support() || options->KeepBindCapabilities == 0)) {
+    const char *extra = "";
+    if (options->KeepBindCapabilities == 0 && have_capability_support())
+      extra = ", and you have disabled KeepBindCapabilities.";
+    log_warn(LD_CONFIG,
+          "You have set AccountingMax to use hibernation. You have also "
+          "chosen a low DirPort or OrPort%s."
+          "This combination can make Tor stop "
+          "working when it tries to re-attach the port after a period of "
+          "hibernation. Please choose a different port or turn off "
+          "hibernation unless you know this combination will work on your "
+          "platform.", extra);
+  }
+
+  if (n_low_ports_out)
+    *n_low_ports_out = n_low_port;
+
+  return r;
+}
+
+/** Parse all relay ports from <b>options</b>. On success, add parsed ports to
+ * <b>ports</b>, and return 0.  On failure, set *<b>msg</b> to a description
+ * of the problem and return -1.
+ **/
+int
+parse_ports_relay(or_options_t *options,
+                  char **msg,
+                  smartlist_t *ports_out,
+                  int *have_low_ports_out)
+{
+  int retval = -1;
+  smartlist_t *ports = smartlist_new();
+
+  if (BUG(!options))
+    goto err;
+
+  if (BUG(!msg))
+    goto err;
+
+  if (BUG(!ports_out))
+    goto err;
+
+  if (BUG(!have_low_ports_out))
+    goto err;
+
+  if (! options->ClientOnly) {
+    if (parse_port_config(ports,
+                          options->ORPort_lines,
+                          "OR", CONN_TYPE_OR_LISTENER,
+                          "0.0.0.0", 0,
+                          CL_PORT_SERVER_OPTIONS) < 0) {
+      *msg = tor_strdup("Invalid ORPort configuration");
+      goto err;
+    }
+    if (parse_port_config(ports,
+                          options->ExtORPort_lines,
+                          "ExtOR", CONN_TYPE_EXT_OR_LISTENER,
+                          "127.0.0.1", 0,
+                          CL_PORT_SERVER_OPTIONS|CL_PORT_WARN_NONLOCAL) < 0) {
+      *msg = tor_strdup("Invalid ExtORPort configuration");
+      goto err;
+    }
+    if (parse_port_config(ports,
+                          options->DirPort_lines,
+                          "Dir", CONN_TYPE_DIR_LISTENER,
+                          "0.0.0.0", 0,
+                          CL_PORT_SERVER_OPTIONS) < 0) {
+      *msg = tor_strdup("Invalid DirPort configuration");
+      goto err;
+    }
+  }
+
+  int n_low_ports = 0;
+  if (check_server_ports(ports, options, &n_low_ports) < 0) {
+    *msg = tor_strdup("Misconfigured server ports");
+    goto err;
+  }
+  if (*have_low_ports_out < 0)
+    *have_low_ports_out = (n_low_ports > 0);
+
+  smartlist_add_all(ports_out, ports);
+  smartlist_free(ports);
+  ports = NULL;
+  retval = 0;
+
+ err:
+  if (ports) {
+    SMARTLIST_FOREACH(ports, port_cfg_t *, p, port_cfg_free(p));
+    smartlist_free(ports);
+  }
+  return retval;
+}
+
+/** Update the relay *Port_set values in <b>options</b> from <b>ports</b>. */
+void
+update_port_set_relay(or_options_t *options,
+                      const smartlist_t *ports)
+{
+  if (BUG(!options))
+    return;
+
+  if (BUG(!ports))
+    return;
+
+  /* Update the relay *Port_set options.  The !! here is to force a boolean
+   * out of an integer. */
+  options->ORPort_set =
+    !! count_real_listeners(ports, CONN_TYPE_OR_LISTENER, 0);
+  options->DirPort_set =
+    !! count_real_listeners(ports, CONN_TYPE_DIR_LISTENER, 0);
+  options->ExtORPort_set =
+    !! count_real_listeners(ports, CONN_TYPE_EXT_OR_LISTENER, 0);
+}