diff --git a/src/common/log.c b/src/common/log.c
index 9f4a8b2bc2..922e9dd38f 100644
--- a/src/common/log.c
+++ b/src/common/log.c
@@ -52,6 +52,13 @@
 
 #define raw_assert(x) assert(x) // assert OK
 
+/** Defining compile-time constants for Tor log levels (used by the Rust
+ * log wrapper at src/rust/tor_log) */
+const int LOG_WARN_ = LOG_WARN;
+const int LOG_NOTICE_ = LOG_NOTICE;
+const log_domain_mask_t LD_GENERAL_ = LD_GENERAL;
+const log_domain_mask_t LD_NET_ = LD_NET;
+
 /** Information for a single logfile; only used in log.c */
 typedef struct logfile_t {
   struct logfile_t *next; /**< Next logfile_t in the linked list. */
@@ -225,6 +232,30 @@ log_set_application_name(const char *name)
   appname = name ? tor_strdup(name) : NULL;
 }
 
+/** Return true if some of the running logs might be interested in a log
+ * message of the given severity in the given domains. If this function
+ * returns true, the log message might be ignored anyway, but if it returns
+ * false, it is definitely_ safe not to log the message. */
+int
+log_message_is_interesting(int severity, log_domain_mask_t domain)
+{
+  (void) domain;
+  return (severity <= log_global_min_severity_);
+}
+
+/**
+ * As tor_log, but takes an optional function name, and does not treat its
+ * <b>string</b> as a printf format.
+ *
+ * For use by Rust integration.
+ */
+void
+tor_log_string(int severity, log_domain_mask_t domain,
+               const char *function, const char *string)
+{
+  log_fn_(severity, domain, function, "%s", string);
+}
+
 /** Log time granularity in milliseconds. */
 static int log_time_granularity = 1;
 
diff --git a/src/common/torlog.h b/src/common/torlog.h
index cadfe3b879..a8b5604d84 100644
--- a/src/common/torlog.h
+++ b/src/common/torlog.h
@@ -31,6 +31,16 @@
  * "maximum severity" read "most severe" and "numerically *lowest* severity".
  */
 
+/** This defines log levels that are linked in the Rust log module, rather
+ * than re-defining these in both Rust and C.
+ *
+ * C_RUST_COUPLED src/rust/tor_log LogSeverity, LogDomain
+ */
+extern const int LOG_WARN_;
+extern const int LOG_NOTICE_;
+extern const log_domain_mask_t LD_NET_;
+extern const log_domain_mask_t LD_GENERAL_;
+
 /** Debug-level severity: for hyper-verbose messages of no interest to
  * anybody but developers. */
 #define LOG_DEBUG   7
@@ -191,6 +201,10 @@ void log_fn_ratelim_(struct ratelim_t *ratelim, int severity,
                      const char *format, ...)
   CHECK_PRINTF(5,6);
 
+int log_message_is_interesting(int severity, log_domain_mask_t domain);
+void tor_log_string(int severity, log_domain_mask_t domain,
+                    const char *function, const char *string);
+
 #if defined(__GNUC__) && __GNUC__ <= 3
 
 /* These are the GCC varidaic macros, so that older versions of GCC don't
diff --git a/src/or/main.c b/src/or/main.c
index 65340751ef..a0d2ae0757 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -133,7 +133,7 @@ void evdns_shutdown(int);
 #ifdef HAVE_RUST
 // helper function defined in Rust to output a log message indicating if tor is
 // running with Rust enabled. See src/rust/tor_util
-char *rust_welcome_string(void);
+void rust_log_welcome_string(void);
 #endif
 
 /********* PROTOTYPES **********/
@@ -3344,11 +3344,7 @@ tor_init(int argc, char *argv[])
   }
 
 #ifdef HAVE_RUST
-  char *rust_str = rust_welcome_string();
-  if (rust_str != NULL && strlen(rust_str) > 0) {
-    log_notice(LD_GENERAL, "%s", rust_str);
-  }
-  tor_free(rust_str);
+  rust_log_welcome_string();
 #endif /* defined(HAVE_RUST) */
 
   if (network_init()<0) {
diff --git a/src/rust/Cargo.lock b/src/rust/Cargo.lock
index 224d2135bf..116ef17f1c 100644
--- a/src/rust/Cargo.lock
+++ b/src/rust/Cargo.lock
@@ -4,6 +4,7 @@ version = "0.0.1"
 dependencies = [
  "libc 0.2.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "tor_allocate 0.0.1",
+ "tor_log 0.1.0",
 ]
 
 [[package]]
@@ -26,6 +27,7 @@ dependencies = [
  "libc 0.2.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "smartlist 0.0.1",
  "tor_allocate 0.0.1",
+ "tor_log 0.1.0",
  "tor_util 0.0.1",
 ]
 
@@ -43,6 +45,14 @@ dependencies = [
  "libc 0.2.22 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "tor_log"
+version = "0.1.0"
+dependencies = [
+ "libc 0.2.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tor_allocate 0.0.1",
+]
+
 [[package]]
 name = "tor_rust"
 version = "0.1.0"
diff --git a/src/rust/Cargo.toml b/src/rust/Cargo.toml
index 953c9b96b7..4ae8033eb3 100644
--- a/src/rust/Cargo.toml
+++ b/src/rust/Cargo.toml
@@ -1,5 +1,6 @@
 [workspace]
-members = ["tor_util", "protover", "smartlist", "external", "tor_allocate", "tor_rust"]
+members = ["tor_util", "protover", "smartlist", "external", "tor_allocate",
+"tor_rust", "tor_log"]
 
 [profile.release]
 debug = true
diff --git a/src/rust/protover/Cargo.toml b/src/rust/protover/Cargo.toml
index 04d2f2ed7d..3f70155ef8 100644
--- a/src/rust/protover/Cargo.toml
+++ b/src/rust/protover/Cargo.toml
@@ -3,6 +3,9 @@ authors = ["The Tor Project"]
 version = "0.0.1"
 name = "protover"
 
+[features]
+testing = ["tor_log/testing"]
+
 [dependencies]
 libc = "0.2.22"
 
@@ -18,6 +21,9 @@ path = "../tor_util"
 [dependencies.tor_allocate]
 path = "../tor_allocate"
 
+[dependencies.tor_log]
+path = "../tor_log"
+
 [lib]
 name = "protover"
 path = "lib.rs"
diff --git a/src/rust/protover/ffi.rs b/src/rust/protover/ffi.rs
index e4cf0a7e88..a9d5013c6d 100644
--- a/src/rust/protover/ffi.rs
+++ b/src/rust/protover/ffi.rs
@@ -127,9 +127,11 @@ pub extern "C" fn protocol_list_supports_protocol_or_later(
         Err(_) => return 0,
     };
 
-    let is_supported =
-        protover_string_supports_protocol_or_later(
-            protocol_list, protocol, version);
+    let is_supported = protover_string_supports_protocol_or_later(
+        protocol_list,
+        protocol,
+        version,
+    );
 
     return if is_supported { 1 } else { 0 };
 }
diff --git a/src/rust/protover/lib.rs b/src/rust/protover/lib.rs
index 8e80fcef4c..d1d49d2a59 100644
--- a/src/rust/protover/lib.rs
+++ b/src/rust/protover/lib.rs
@@ -29,6 +29,9 @@ extern crate tor_allocate;
 #[macro_use]
 extern crate tor_util;
 
+#[macro_use]
+extern crate tor_log;
+
 mod protover;
 pub mod ffi;
 
diff --git a/src/rust/protover/protover.rs b/src/rust/protover/protover.rs
index 03776411ca..fd1f41d780 100644
--- a/src/rust/protover/protover.rs
+++ b/src/rust/protover/protover.rs
@@ -1,8 +1,6 @@
 // Copyright (c) 2016-2017, The Tor Project, Inc. */
 // See LICENSE for licensing information */
 
-use external::c_tor_version_as_new_as;
-
 use std::str;
 use std::str::FromStr;
 use std::ffi::CStr;
@@ -12,6 +10,9 @@ use std::ops::Range;
 use std::string::String;
 use std::u32;
 
+use tor_log::{LogSeverity, LogDomain};
+use external::c_tor_version_as_new_as;
+
 /// The first version of Tor that included "proto" entries in its descriptors.
 /// Authorities should use this to decide whether to guess proto lines.
 ///
@@ -225,7 +226,6 @@ impl Versions {
     }
 }
 
-
 /// Parse the subprotocol type and its version numbers.
 ///
 /// # Inputs
@@ -279,6 +279,20 @@ fn get_proto_and_vers<'a>(
 fn contains_only_supported_protocols(proto_entry: &str) -> bool {
     let (name, mut vers) = match get_proto_and_vers(proto_entry) {
         Ok(n) => n,
+        Err("Too many versions to expand") => {
+            tor_log_msg!(
+                LogSeverity::Warn,
+                LogDomain::Net,
+                "get_versions",
+                "When expanding a protocol list from an authority, I \
+                got too many protocols. This is possibly an attack or a bug, \
+                unless the Tor network truly has expanded to support over {} \
+                different subprotocol versions. The offending string was: {}",
+                MAX_PROTOCOLS_TO_EXPAND,
+                proto_entry
+            );
+            return false;
+        }
         Err(_) => return false,
     };
 
diff --git a/src/rust/tor_allocate/tor_allocate.rs b/src/rust/tor_allocate/tor_allocate.rs
index 359df1cd7a..3c0037f139 100644
--- a/src/rust/tor_allocate/tor_allocate.rs
+++ b/src/rust/tor_allocate/tor_allocate.rs
@@ -1,12 +1,17 @@
 // Copyright (c) 2016-2017, The Tor Project, Inc. */
 // See LICENSE for licensing information */
+// No-op defined purely for testing at the module level
+use libc::c_char;
 
-use libc::{c_char, c_void};
+#[cfg(not(feature = "testing"))]
 use std::{ptr, slice, mem};
+use libc::c_void;
 
-#[cfg(not(test))]
-extern "C" {
-    fn tor_malloc_(size: usize) -> *mut c_void;
+// Define a no-op implementation for testing Rust modules without linking to C
+#[cfg(feature = "testing")]
+pub fn allocate_and_copy_string(s: &String) -> *mut c_char {
+    use std::ffi::CString;
+    CString::new(s.as_str()).unwrap().into_raw()
 }
 
 // Defined only for tests, used for testing purposes, so that we don't need
@@ -17,6 +22,11 @@ unsafe extern "C" fn tor_malloc_(size: usize) -> *mut c_void {
     malloc(size)
 }
 
+#[cfg(all(not(test), not(feature = "testing")))]
+extern "C" {
+    fn tor_malloc_(size: usize) -> *mut c_void;
+}
+
 /// Allocate memory using tor_malloc_ and copy an existing string into the
 /// allocated buffer, returning a pointer that can later be called in C.
 ///
@@ -28,6 +38,7 @@ unsafe extern "C" fn tor_malloc_(size: usize) -> *mut c_void {
 ///
 /// A `*mut c_char` that should be freed by tor_free in C
 ///
+#[cfg(not(feature = "testing"))]
 pub fn allocate_and_copy_string(src: &String) -> *mut c_char {
     let bytes: &[u8] = src.as_bytes();
 
diff --git a/src/rust/tor_log/Cargo.toml b/src/rust/tor_log/Cargo.toml
new file mode 100644
index 0000000000..f31d27b045
--- /dev/null
+++ b/src/rust/tor_log/Cargo.toml
@@ -0,0 +1,18 @@
+[package]
+name = "tor_log"
+version = "0.1.0"
+authors = ["The Tor Project"]
+
+[lib]
+name = "tor_log"
+path = "lib.rs"
+crate_type = ["rlib", "staticlib"]
+
+[features]
+testing = []
+
+[dependencies]
+libc = "0.2.22"
+
+[dependencies.tor_allocate]
+path = "../tor_allocate"
diff --git a/src/rust/tor_log/lib.rs b/src/rust/tor_log/lib.rs
new file mode 100644
index 0000000000..72f9e38339
--- /dev/null
+++ b/src/rust/tor_log/lib.rs
@@ -0,0 +1,16 @@
+//! Copyright (c) 2016-2017, The Tor Project, Inc. */
+//! See LICENSE for licensing information */
+
+//! Logging wrapper for Rust to utilize Tor's logger, found at
+//! src/common/log.c and src/common/torlog.h
+//!
+//! Exposes different interfaces depending on whether we are running in test
+//! or non-test mode. When testing, we use a no-op implementation,
+//! otherwise we link directly to C.
+
+extern crate libc;
+extern crate tor_allocate;
+
+mod tor_log;
+
+pub use tor_log::*;
diff --git a/src/rust/tor_log/tor_log.rs b/src/rust/tor_log/tor_log.rs
new file mode 100644
index 0000000000..1fdc0026bf
--- /dev/null
+++ b/src/rust/tor_log/tor_log.rs
@@ -0,0 +1,270 @@
+// Copyright (c) 2016-2017, The Tor Project, Inc. */
+// See LICENSE for licensing information */
+
+// Note that these functions are untested due to the fact that there are no
+// return variables to test and they are calling into a C API.
+
+/// The related domain which the logging message is relevant. For example,
+/// log messages relevant to networking would use LogDomain::LdNet, whereas
+/// general messages can use LdGeneral.
+#[derive(Eq, PartialEq)]
+pub enum LogDomain {
+    Net,
+    General,
+}
+
+/// The severity level at which to log messages.
+#[derive(Eq, PartialEq)]
+pub enum LogSeverity {
+    Notice,
+    Warn,
+}
+
+/// Main entry point for Rust modules to log messages.
+///
+/// # Inputs
+///
+/// * A `severity` of type LogSeverity, which defines the level of severity the
+/// message will be logged.
+/// * A `domain` of type LogDomain, which defines the domain the log message
+/// will be associated with.
+/// * A `function` of type &str, which defines the name of the function where
+/// the message is being logged. There is a current RFC for a macro that
+/// defines function names. When it is, we should use it. See
+/// https://github.com/rust-lang/rfcs/pull/1719
+/// * A `message` of type &str, which is the log message itself.
+#[macro_export]
+macro_rules! tor_log_msg {
+    ($severity: path,
+     $domain: path,
+     $function: expr,
+     $($message:tt)*) =>
+    {
+        {
+            let msg = format!($($message)*);
+            $crate::tor_log_msg_impl($severity, $domain, $function, msg)
+        }
+    };
+}
+
+#[inline]
+pub fn tor_log_msg_impl(
+    severity: LogSeverity,
+    domain: LogDomain,
+    function: &str,
+    message: String,
+) {
+    use std::ffi::CString;
+
+    /// Default function name to log in case of errors when converting
+    /// a function name to a CString
+    const ERR_LOG_FUNCTION: &str = "tor_log_msg";
+
+    /// Default message to log in case of errors when converting a log
+    /// message to a CString
+    const ERR_LOG_MSG: &str = "Unable to log message from Rust \
+            module due to error when converting to CString";
+
+    let func = match CString::new(function) {
+        Ok(n) => n,
+        Err(_) => CString::new(ERR_LOG_FUNCTION).unwrap(),
+    };
+
+    let msg = match CString::new(message) {
+        Ok(n) => n,
+        Err(_) => CString::new(ERR_LOG_MSG).unwrap(),
+    };
+
+    // Bind to a local variable to preserve ownership. This is essential so
+    // that ownership is guaranteed until these local variables go out of scope
+    let func_ptr = func.as_ptr();
+    let msg_ptr = msg.as_ptr();
+
+    let c_severity = unsafe { log::translate_severity(severity) };
+    let c_domain = unsafe { log::translate_domain(domain) };
+
+    unsafe { log::tor_log_string(c_severity, c_domain, func_ptr, msg_ptr) }
+}
+
+/// This implementation is used when compiling for actual use, as opposed to
+/// testing.
+#[cfg(all(not(test), not(feature = "testing")))]
+pub mod log {
+    use libc::{c_char, c_int};
+    use super::LogDomain;
+    use super::LogSeverity;
+
+    /// Severity log types. These mirror definitions in /src/common/torlog.h
+    /// C_RUST_COUPLED: src/common/log.c, log domain types
+    extern "C" {
+        static LOG_WARN_: c_int;
+        static LOG_NOTICE_: c_int;
+    }
+
+    /// Domain log types. These mirror definitions in /src/common/torlog.h
+    /// C_RUST_COUPLED: src/common/log.c, log severity types
+    extern "C" {
+        static LD_NET_: u32;
+        static LD_GENERAL_: u32;
+    }
+
+    /// Translate Rust defintions of log domain levels to C. This exposes a 1:1
+    /// mapping between types.
+    #[inline]
+    pub unsafe fn translate_domain(domain: LogDomain) -> u32 {
+        match domain {
+            LogDomain::Net => LD_NET_,
+            LogDomain::General => LD_GENERAL_,
+        }
+    }
+
+    /// Translate Rust defintions of log severity levels to C. This exposes a
+    /// 1:1 mapping between types.
+    #[inline]
+    pub unsafe fn translate_severity(severity: LogSeverity) -> c_int {
+        match severity {
+            LogSeverity::Warn => LOG_WARN_,
+            LogSeverity::Notice => LOG_NOTICE_,
+        }
+    }
+
+    /// The main entry point into Tor's logger. When in non-test mode, this
+    /// will link directly with `tor_log_string` in /src/or/log.c
+    extern "C" {
+        pub fn tor_log_string(
+            severity: c_int,
+            domain: u32,
+            function: *const c_char,
+            string: *const c_char,
+        );
+    }
+}
+
+/// This module exposes no-op functionality for testing other Rust modules
+/// without linking to C.
+#[cfg(any(test, feature = "testing"))]
+pub mod log {
+    use libc::{c_char, c_int};
+    use super::LogDomain;
+    use super::LogSeverity;
+
+    pub static mut LAST_LOGGED_FUNCTION: *mut String = 0 as *mut String;
+    pub static mut LAST_LOGGED_MESSAGE: *mut String = 0 as *mut String;
+
+    pub unsafe fn tor_log_string(
+        _severity: c_int,
+        _domain: u32,
+        function: *const c_char,
+        message: *const c_char,
+    ) {
+        use std::ffi::CStr;
+
+        let f = CStr::from_ptr(function);
+        let fct = match f.to_str() {
+            Ok(n) => n,
+            Err(_) => "",
+        };
+        LAST_LOGGED_FUNCTION = Box::into_raw(Box::new(String::from(fct)));
+
+        let m = CStr::from_ptr(message);
+        let msg = match m.to_str() {
+            Ok(n) => n,
+            Err(_) => "",
+        };
+        LAST_LOGGED_MESSAGE = Box::into_raw(Box::new(String::from(msg)));
+    }
+
+    pub unsafe fn translate_domain(_domain: LogDomain) -> u32 {
+        1
+    }
+
+    pub unsafe fn translate_severity(_severity: LogSeverity) -> c_int {
+        1
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use tor_log::*;
+    use tor_log::log::{LAST_LOGGED_FUNCTION, LAST_LOGGED_MESSAGE};
+
+    #[test]
+    fn test_get_log_message() {
+        {
+            fn test_macro() {
+                tor_log_msg!(
+                    LogSeverity::Warn,
+                    LogDomain::Net,
+                    "test_macro",
+                    "test log message {}",
+                    "a",
+                    );
+            }
+
+            test_macro();
+
+            let function = unsafe { Box::from_raw(LAST_LOGGED_FUNCTION) };
+            assert_eq!("test_macro", *function);
+
+            let message = unsafe { Box::from_raw(LAST_LOGGED_MESSAGE) };
+            assert_eq!("test log message a", *message);
+        }
+
+        // test multiple inputs into the log message
+        {
+            fn test_macro() {
+                tor_log_msg!(
+                    LogSeverity::Warn,
+                    LogDomain::Net,
+                    "next_test_macro",
+                    "test log message {} {} {} {} {}",
+                    1,
+                    2,
+                    3,
+                    4,
+                    5
+                );
+            }
+
+            test_macro();
+
+            let function = unsafe { Box::from_raw(LAST_LOGGED_FUNCTION) };
+            assert_eq!("next_test_macro", *function);
+
+            let message = unsafe { Box::from_raw(LAST_LOGGED_MESSAGE) };
+            assert_eq!("test log message 1 2 3 4 5", *message);
+        }
+
+        // test how a long log message will be formatted
+        {
+            fn test_macro() {
+                tor_log_msg!(
+                    LogSeverity::Warn,
+                    LogDomain::Net,
+                    "test_macro",
+                    "{}",
+                    "All the world's a stage, and all the men and women \
+                    merely players: they have their exits and their \
+                    entrances; and one man in his time plays many parts, his \
+                    acts being seven ages."
+                );
+            }
+
+            test_macro();
+
+            let expected_string = "All the world's a \
+                stage, and all the men \
+                and women merely players: \
+                they have their exits and \
+                their entrances; and one man \
+                in his time plays many parts, \
+                his acts being seven ages.";
+
+            let function = unsafe { Box::from_raw(LAST_LOGGED_FUNCTION) };
+            assert_eq!("test_macro", *function);
+
+            let message = unsafe { Box::from_raw(LAST_LOGGED_MESSAGE) };
+            assert_eq!(expected_string, *message);
+        }
+    }
+}
diff --git a/src/rust/tor_util/Cargo.toml b/src/rust/tor_util/Cargo.toml
index d7379a5988..adc3390b53 100644
--- a/src/rust/tor_util/Cargo.toml
+++ b/src/rust/tor_util/Cargo.toml
@@ -11,6 +11,9 @@ crate_type = ["rlib", "staticlib"]
 [dependencies.tor_allocate]
 path = "../tor_allocate"
 
+[dependencies.tor_log]
+path = "../tor_log"
+
 [dependencies]
 libc = "0.2.22"
 
diff --git a/src/rust/tor_util/ffi.rs b/src/rust/tor_util/ffi.rs
index 5c3cdba4be..32779ed476 100644
--- a/src/rust/tor_util/ffi.rs
+++ b/src/rust/tor_util/ffi.rs
@@ -5,8 +5,7 @@
 //! called from C.
 //!
 
-use libc::c_char;
-use tor_allocate::allocate_and_copy_string;
+use tor_log::{LogSeverity, LogDomain};
 
 /// Returns a short string to announce Rust support during startup.
 ///
@@ -17,10 +16,12 @@ use tor_allocate::allocate_and_copy_string;
 /// tor_free(rust_str);
 /// ```
 #[no_mangle]
-pub extern "C" fn rust_welcome_string() -> *mut c_char {
-    let rust_welcome = String::from(
+pub extern "C" fn rust_log_welcome_string() {
+    tor_log_msg!(
+        LogSeverity::Notice,
+        LogDomain::General,
+        "rust_log_welcome_string",
         "Tor is running with Rust integration. Please report \
-         any bugs you encounter.",
+        any bugs you encounter."
     );
-    allocate_and_copy_string(&rust_welcome)
 }
diff --git a/src/rust/tor_util/lib.rs b/src/rust/tor_util/lib.rs
index 12cb3896b6..94697b6069 100644
--- a/src/rust/tor_util/lib.rs
+++ b/src/rust/tor_util/lib.rs
@@ -7,5 +7,8 @@
 extern crate libc;
 extern crate tor_allocate;
 
+#[macro_use]
+extern crate tor_log;
+
 pub mod ffi;
 pub mod strings;
diff --git a/src/test/test_rust.sh b/src/test/test_rust.sh
index 133f2bb940..0268668b3d 100755
--- a/src/test/test_rust.sh
+++ b/src/test/test_rust.sh
@@ -11,7 +11,7 @@ for crate in $crates; do
     cd "${abs_top_builddir:-../../..}/src/rust"
     CARGO_TARGET_DIR="${abs_top_builddir:-../../..}/src/rust/target" \
       CARGO_HOME="${abs_top_builddir:-../../..}/src/rust" \
-      "${CARGO:-cargo}" test ${CARGO_ONLINE-"--frozen"} \
+      "${CARGO:-cargo}" test --all-features ${CARGO_ONLINE-"--frozen"} \
       --manifest-path "${abs_top_srcdir:-.}/src/rust/${crate}/Cargo.toml" \
 	|| exitcode=1
     cd -