config: Move accounting/bandwidth config into the relay module

This commit:
* moves accounting and bandwidth checks into relay_config,
* moves testing options checks into relay_config,
* moves some other minor checks into relay_config,
* 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. (Some of the checks
are re-ordered, so the order of some warnings may change.)

Part of 32213.

1 files changed, 167 insertions, 0 deletions

diff --git a/src/feature/relay/relay_config.c b/src/feature/relay/relay_config.c
index 1d33f12b30..7f1f046653 100644
--- a/src/feature/relay/relay_config.c
+++ b/src/feature/relay/relay_config.c
@@ -27,6 +27,7 @@
 #include "core/mainloop/connection.h"
 #include "core/or/port_cfg_st.h"
 
+#include "feature/hibernate/hibernate.h"
 #include "feature/nodelist/nickname.h"
 
 #include "feature/relay/dns.h"
@@ -522,6 +523,29 @@ options_validate_relay_bandwidth(const or_options_t *old_options,
   if (BUG(!msg))
     return -1;
 
+  /* 31851: the tests expect us to validate bandwidths, even when we are not
+  * in relay mode. */
+  if (ensure_bandwidth_cap(&options->MaxAdvertisedBandwidth,
+                           "MaxAdvertisedBandwidth", msg) < 0)
+    return -1;
+  if (ensure_bandwidth_cap(&options->RelayBandwidthRate,
+                           "RelayBandwidthRate", msg) < 0)
+    return -1;
+  if (ensure_bandwidth_cap(&options->RelayBandwidthBurst,
+                           "RelayBandwidthBurst", msg) < 0)
+    return -1;
+  if (ensure_bandwidth_cap(&options->PerConnBWRate,
+                           "PerConnBWRate", msg) < 0)
+    return -1;
+  if (ensure_bandwidth_cap(&options->PerConnBWBurst,
+                           "PerConnBWBurst", msg) < 0)
+    return -1;
+
+  if (options->RelayBandwidthRate && !options->RelayBandwidthBurst)
+    options->RelayBandwidthBurst = options->RelayBandwidthRate;
+  if (options->RelayBandwidthBurst && !options->RelayBandwidthRate)
+    options->RelayBandwidthRate = options->RelayBandwidthBurst;
+
   if (server_mode(options)) {
     const unsigned required_min_bw =
       public_server_mode(options) ?
@@ -555,6 +579,101 @@ options_validate_relay_bandwidth(const or_options_t *old_options,
     }
   }
 
+  /* 31851: the tests expect us to validate bandwidths, even when we are not
+   * in relay mode. */
+  if (options->RelayBandwidthRate > options->RelayBandwidthBurst)
+    REJECT("RelayBandwidthBurst must be at least equal "
+           "to RelayBandwidthRate.");
+
+  /* if they set relaybandwidth* really high but left bandwidth*
+   * at the default, raise the defaults. */
+  if (options->RelayBandwidthRate > options->BandwidthRate)
+    options->BandwidthRate = options->RelayBandwidthRate;
+  if (options->RelayBandwidthBurst > options->BandwidthBurst)
+    options->BandwidthBurst = options->RelayBandwidthBurst;
+
+  return 0;
+}
+
+/** Return the bandwidthrate that we are going to report to the authorities
+ * based on the config options. */
+uint32_t
+get_effective_bwrate(const or_options_t *options)
+{
+  uint64_t bw = options->BandwidthRate;
+  if (bw > options->MaxAdvertisedBandwidth)
+    bw = options->MaxAdvertisedBandwidth;
+  if (options->RelayBandwidthRate > 0 && bw > options->RelayBandwidthRate)
+    bw = options->RelayBandwidthRate;
+  /* ensure_bandwidth_cap() makes sure that this cast can't overflow. */
+  return (uint32_t)bw;
+}
+
+/** Return the bandwidthburst that we are going to report to the authorities
+ * based on the config options. */
+uint32_t
+get_effective_bwburst(const or_options_t *options)
+{
+  uint64_t bw = options->BandwidthBurst;
+  if (options->RelayBandwidthBurst > 0 && bw > options->RelayBandwidthBurst)
+    bw = options->RelayBandwidthBurst;
+  /* ensure_bandwidth_cap() makes sure that this cast can't overflow. */
+  return (uint32_t)bw;
+}
+
+/**
+ * Legacy validation/normalization function for the relay bandwidth accounting
+ * options. Uses old_options as the previous options.
+ *
+ * Returns 0 on success, returns -1 and sets *msg to a newly allocated string
+ * on error.
+ */
+int
+options_validate_relay_accounting(const or_options_t *old_options,
+                                  or_options_t *options,
+                                  char **msg)
+{
+  (void)old_options;
+
+  if (BUG(!options))
+    return -1;
+
+  if (BUG(!msg))
+    return -1;
+
+  /* 31851: the tests expect us to validate accounting, even when we are not
+   * in relay mode. */
+  if (accounting_parse_options(options, 1)<0)
+    REJECT("Failed to parse accounting options. See logs for details.");
+
+  if (options->AccountingMax) {
+    if (options->RendConfigLines && server_mode(options)) {
+      log_warn(LD_CONFIG, "Using accounting with a hidden service and an "
+               "ORPort is risky: your hidden service(s) and your public "
+               "address will all turn off at the same time, which may alert "
+               "observers that they are being run by the same party.");
+    } else if (config_count_key(options->RendConfigLines,
+                                "HiddenServiceDir") > 1) {
+      log_warn(LD_CONFIG, "Using accounting with multiple hidden services is "
+               "risky: they will all turn off at the same time, which may "
+               "alert observers that they are being run by the same party.");
+    }
+  }
+
+  options->AccountingRule = ACCT_MAX;
+  if (options->AccountingRule_option) {
+    if (!strcmp(options->AccountingRule_option, "sum"))
+      options->AccountingRule = ACCT_SUM;
+    else if (!strcmp(options->AccountingRule_option, "max"))
+      options->AccountingRule = ACCT_MAX;
+    else if (!strcmp(options->AccountingRule_option, "in"))
+      options->AccountingRule = ACCT_IN;
+    else if (!strcmp(options->AccountingRule_option, "out"))
+      options->AccountingRule = ACCT_OUT;
+    else
+      REJECT("AccountingRule must be 'sum', 'max', 'in', or 'out'");
+  }
+
   return 0;
 }
 
@@ -703,6 +822,13 @@ options_validate_relay_mode(const or_options_t *old_options,
   if (BUG(!msg))
     return -1;
 
+  if (server_mode(options) && options->RendConfigLines)
+    log_warn(LD_CONFIG,
+        "Tor is currently configured as a relay and a hidden service. "
+        "That's not very secure: you should probably run your hidden service "
+        "in a separate Tor process, at least -- see "
+        "https://trac.torproject.org/8742");
+
   if (options->BridgeRelay && options->DirPort_set) {
     log_warn(LD_CONFIG, "Can't set a DirPort on a bridge relay; disabling "
              "DirPort");
@@ -747,5 +873,46 @@ options_validate_relay_mode(const or_options_t *old_options,
                               options->MyFamily_lines, "MyFamily", msg))
     return -1;
 
+  if (options->ConstrainedSockets) {
+    if (options->DirPort_set) {
+      /* Providing cached directory entries while system TCP buffers are scarce
+       * will exacerbate the socket errors.  Suggest that this be disabled. */
+      COMPLAIN("You have requested constrained socket buffers while also "
+               "serving directory entries via DirPort.  It is strongly "
+               "suggested that you disable serving directory requests when "
+               "system TCP buffer resources are scarce.");
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Legacy validation/normalization function for the relay testing options
+ * in options. Uses old_options as the previous options.
+ *
+ * Returns 0 on success, returns -1 and sets *msg to a newly allocated string
+ * on error.
+ */
+int
+options_validate_relay_testing(const or_options_t *old_options,
+                               or_options_t *options,
+                               char **msg)
+{
+  (void)old_options;
+
+  if (BUG(!options))
+    return -1;
+
+  if (BUG(!msg))
+    return -1;
+
+  if (options->SigningKeyLifetime < options->TestingSigningKeySlop*2)
+    REJECT("SigningKeyLifetime is too short.");
+  if (options->TestingLinkCertLifetime < options->TestingAuthKeySlop*2)
+    REJECT("LinkCertLifetime is too short.");
+  if (options->TestingAuthKeyLifetime < options->TestingLinkKeySlop*2)
+    REJECT("TestingAuthKeyLifetime is too short.");
+
   return 0;
 }