diff --git a/include/libtorrent/alert_types.hpp b/include/libtorrent/alert_types.hpp
index 0a63445b9..c342d28cb 100644
--- a/include/libtorrent/alert_types.hpp
+++ b/include/libtorrent/alert_types.hpp
@@ -1436,8 +1436,6 @@ namespace libtorrent
 		int protocol;
 	};
 
-#ifndef TORRENT_DISABLE_LOGGING
-
 	// This alert is generated to log informational events related to either
 	// UPnP or NAT-PMP. They contain a log line and the type (0 = NAT-PMP
 	// and 1 = UPnP). Displaying these messages to an end user is only useful
@@ -1471,8 +1469,6 @@ namespace libtorrent
 		int m_log_idx;
 	};
 
-#endif
-
 	// This alert is generated when a fastresume file has been passed to
 	// add_torrent() but the files on disk did not match the fastresume file.
 	// The error_code explains the reason why the resume file was rejected.
@@ -2077,7 +2073,6 @@ namespace libtorrent
 		udp::endpoint ip;
 	};
 
-#ifndef TORRENT_DISABLE_LOGGING
 	// This alert is posted by some session wide event. Its main purpose is
 	// trouble shooting and debugging. It's not enabled by the default alert
 	// mask and is enabled by the ``alert::session_log_notification`` bit.
@@ -2164,8 +2159,6 @@ namespace libtorrent
 		int m_str_idx;
 	};
 
-#endif
-
 	// posted if the local service discovery socket fails to start properly.
 	// it's categorized as ``error_notification``.
 	struct TORRENT_EXPORT lsd_error_alert final : alert
@@ -2318,8 +2311,8 @@ namespace libtorrent
 		enum direction_t
 		{ incoming, outgoing };
 
-		dht_pkt_alert(aux::stack_allocator& alloc, char const* buf, int size
-			, dht_pkt_alert::direction_t d, udp::endpoint ep);
+		dht_pkt_alert(aux::stack_allocator& alloc, span<char const> buf
+			, dht_pkt_alert::direction_t d, udp::endpoint const& ep);
 
 		static const int static_category = alert::dht_log_notification;
 		TORRENT_DEFINE_ALERT(dht_pkt_alert, 86)
@@ -2330,20 +2323,19 @@ namespace libtorrent
 		// respectively. This buffer is only valid for as long as the alert itself
 		// is valid, which is owned by libtorrent and reclaimed whenever
 		// pop_alerts() is called on the session.
-		char const* pkt_buf() const;
-		int pkt_size() const;
+		span<char const> pkt_buf() const;
 
 		// whether this is an incoming or outgoing packet.
-		direction_t dir;
+		direction_t const dir;
 
 		// the DHT node we received this packet from, or sent this packet to
 		// (depending on ``dir``).
-		udp::endpoint node;
+		udp::endpoint const node;
 
 	private:
 		std::reference_wrapper<aux::stack_allocator> m_alloc;
-		int m_msg_idx;
-		int m_size;
+		int const m_msg_idx;
+		int const m_size;
 	};
 
 	struct TORRENT_EXPORT dht_get_peers_reply_alert final : alert {
@@ -2369,7 +2361,7 @@ namespace libtorrent
 
 	private:
 		std::reference_wrapper<aux::stack_allocator> m_alloc;
-		int m_num_peers;
+		int const m_num_peers;
 		int m_peers_idx;
 	};
 
@@ -2389,15 +2381,15 @@ namespace libtorrent
 		static const int static_category = alert::dht_notification;
 		virtual std::string message() const override;
 
-		void* userdata;
-		udp::endpoint addr;
+		void const* userdata;
+		udp::endpoint const addr;
 
 		bdecode_node response() const;
 
 	private:
 		std::reference_wrapper<aux::stack_allocator> m_alloc;
-		int m_response_idx;
-		int m_response_size;
+		int const m_response_idx;
+		int const m_response_size;
 	};
 
 	// this is posted when one or more blocks are picked by the piece picker,
@@ -2405,8 +2397,6 @@ namespace libtorrent
 	// picker_log_notification).
 	struct TORRENT_EXPORT picker_log_alert : peer_alert
 	{
-#ifndef TORRENT_DISABLE_LOGGING
-
 		// internal
 		picker_log_alert(aux::stack_allocator& alloc, torrent_handle const& h
 			, tcp::endpoint const& ep, peer_id const& peer_id, std::uint32_t flags
@@ -2417,8 +2407,6 @@ namespace libtorrent
 		static const int static_category = alert::picker_log_notification;
 		virtual std::string message() const override;
 
-#endif // TORRENT_DISABLE_LOGGING
-
 		enum picker_flags_t
 		{
 			// the ratio of partial pieces is too high. This forces a preference
@@ -2441,21 +2429,15 @@ namespace libtorrent
 			end_game               = 0x8000
 		};
 
-#ifndef TORRENT_DISABLE_LOGGING
-
 		// this is a bitmask of which features were enabled for this particular
 		// pick. The bits are defined in the picker_flags_t enum.
-		std::uint32_t picker_flags;
+		std::uint32_t const picker_flags;
 
 		std::vector<piece_block> blocks() const;
 
 	private:
-		int m_array_idx;
-		int m_num_blocks;
-#else
-	picker_log_alert(aux::stack_allocator& alloc)
-		: peer_alert(alloc, torrent_handle(), tcp::endpoint(), peer_id()) {}
-#endif // TORRENT_DISABLE_LOGGING
+		int const m_array_idx;
+		int const m_num_blocks;
 	};
 
 #undef TORRENT_DEFINE_ALERT_IMPL
diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index b0a184c81..d987bfe9c 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -624,7 +624,7 @@ namespace libtorrent
 			virtual bool should_log(module_t m) const override;
 			virtual void log(module_t m, char const* fmt, ...)
 				override TORRENT_FORMAT(3,4);
-			virtual void log_packet(message_direction_t dir, char const* pkt, int len
+			virtual void log_packet(message_direction_t dir, span<char const> pkt
 				, udp::endpoint const& node) override;
 
 			virtual bool should_log_portmap(aux::portmap_transport transport) const override;
diff --git a/include/libtorrent/block_cache.hpp b/include/libtorrent/block_cache.hpp
index 474df8e9f..43dc89b50 100644
--- a/include/libtorrent/block_cache.hpp
+++ b/include/libtorrent/block_cache.hpp
@@ -53,7 +53,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/disk_buffer_pool.hpp"
 #include "libtorrent/file.hpp" // for iovec_t
 
-#if TORRENT_USE_ASSERTS
+#if TORRENT_USE_ASSERTS || !defined TORRENT_DISABLE_LOGGING
 #include "libtorrent/disk_io_job.hpp"
 #endif
 
@@ -61,7 +61,6 @@ namespace libtorrent
 {
 	struct disk_io_job;
 	class piece_manager;
-	struct disk_buffer_pool;
 	struct cache_status;
 	struct block_cache_reference;
 	struct counters;
@@ -70,7 +69,8 @@ namespace libtorrent
 	class file_storage;
 #endif
 
-#if TORRENT_USE_ASSERTS
+#if TORRENT_USE_ASSERTS || !defined TORRENT_DISABLE_LOGGING
+
 	struct piece_log_t
 	{
 		piece_log_t(int j, int b= -1): job(j), block(b) {}
@@ -97,9 +97,11 @@ namespace libtorrent
 
 	char const* job_name(int j);
 
+#endif // TORRENT_DISABLE_LOGGING
+
+#if TORRENT_USE_ASSERTS
 	void print_piece_log(std::vector<piece_log_t> const& piece_log);
 	void assert_print_piece(cached_piece_entry const* pe);
-
 #endif
 
 	extern const char* const job_action_name[];
diff --git a/include/libtorrent/kademlia/dht_observer.hpp b/include/libtorrent/kademlia/dht_observer.hpp
index 4e71bd35d..03d12e524 100644
--- a/include/libtorrent/kademlia/dht_observer.hpp
+++ b/include/libtorrent/kademlia/dht_observer.hpp
@@ -59,7 +59,7 @@ namespace libtorrent { namespace dht
 
 		virtual bool should_log(module_t m) const = 0;
 		virtual void log(module_t m, char const* fmt, ...) TORRENT_FORMAT(3,4) = 0;
-		virtual void log_packet(message_direction_t dir, char const* pkt, int len
+		virtual void log_packet(message_direction_t dir, span<char const> pkt
 			, udp::endpoint const& node) = 0;
 #endif
 
diff --git a/include/libtorrent/kademlia/dht_tracker.hpp b/include/libtorrent/kademlia/dht_tracker.hpp
index 414534a52..744369057 100644
--- a/include/libtorrent/kademlia/dht_tracker.hpp
+++ b/include/libtorrent/kademlia/dht_tracker.hpp
@@ -138,7 +138,7 @@ namespace libtorrent { namespace dht
 
 		// implements udp_socket_interface
 		virtual bool has_quota() override;
-		virtual bool send_packet(libtorrent::entry& e, udp::endpoint const& addr) override;
+		virtual bool send_packet(entry& e, udp::endpoint const& addr) override;
 
 		// this is the bdecode_node DHT messages are parsed into. It's a member
 		// in order to avoid having to deallocate and re-allocate it for every
diff --git a/include/libtorrent/stack_allocator.hpp b/include/libtorrent/stack_allocator.hpp
index c956e7feb..29c59dad8 100644
--- a/include/libtorrent/stack_allocator.hpp
+++ b/include/libtorrent/stack_allocator.hpp
@@ -33,7 +33,9 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_STACK_ALLOCATOR
 
 #include "libtorrent/assert.hpp"
-#include "libtorrent/buffer.hpp"
+#include "libtorrent/span.hpp"
+
+#include <cstring>
 
 namespace libtorrent { namespace aux
 {
@@ -48,18 +50,18 @@ namespace libtorrent { namespace aux
 
 		int copy_string(std::string const& str)
 		{
-			int ret = int(m_storage.size());
+			int const ret = int(m_storage.size());
 			m_storage.resize(ret + str.length() + 1);
-			strcpy(&m_storage[ret], str.c_str());
+			std::strcpy(&m_storage[ret], str.c_str());
 			return ret;
 		}
 
 		int copy_string(char const* str)
 		{
-			int ret = int(m_storage.size());
-			int len = int(strlen(str));
+			int const ret = int(m_storage.size());
+			int const len = int(std::strlen(str));
 			m_storage.resize(ret + len + 1);
-			strcpy(&m_storage[ret], str);
+			std::strcpy(&m_storage[ret], str);
 			return ret;
 		}
 
@@ -84,19 +86,19 @@ namespace libtorrent { namespace aux
 			return ret;
 		}
 
-		// TODO: 3 use span<> here
-		int copy_buffer(char const* buf, int const size)
+		int copy_buffer(span<char const> buf)
 		{
 			int const ret = int(m_storage.size());
+			int const size = int(buf.size());
 			m_storage.resize(ret + size);
-			memcpy(&m_storage[ret], buf, size);
+			std::memcpy(&m_storage[ret], buf.data(), size);
 			return ret;
 		}
 
 		int allocate(int const bytes)
 		{
 			TORRENT_ASSERT(bytes >= 0);
-			int ret = int(m_storage.size());
+			int const ret = int(m_storage.size());
 			m_storage.resize(ret + bytes);
 			return ret;
 		}
@@ -133,4 +135,3 @@ namespace libtorrent { namespace aux
 } }
 
 #endif
-
diff --git a/simulation/test_dht_rate_limit.cpp b/simulation/test_dht_rate_limit.cpp
index 30942b2c1..52fc2ea4c 100644
--- a/simulation/test_dht_rate_limit.cpp
+++ b/simulation/test_dht_rate_limit.cpp
@@ -80,7 +80,7 @@ struct obs : dht::dht_observer
 		puts("\n");
 	}
 	void log_packet(message_direction_t /* dir */
-		, char const* /* pkt */, int /* len */
+		, span<char const> /* pkt */
 		, udp::endpoint const& /* node */) override {}
 	bool on_dht_request(string_view /* query */
 		, dht::msg const& /* request */, entry& /* response */) override
diff --git a/src/alert.cpp b/src/alert.cpp
index 307545bd6..cf560d508 100644
--- a/src/alert.cpp
+++ b/src/alert.cpp
@@ -1029,8 +1029,6 @@ namespace libtorrent {
 		return ret;
 	}
 
-#ifndef TORRENT_DISABLE_LOGGING
-
 	portmap_log_alert::portmap_log_alert(aux::stack_allocator& alloc, int t, const char* m)
 		: map_type(t)
 #ifndef TORRENT_NO_DEPRECATE
@@ -1057,8 +1055,6 @@ namespace libtorrent {
 		return ret;
 	}
 
-#endif
-
 	fastresume_rejected_alert::fastresume_rejected_alert(
 		aux::stack_allocator& alloc
 		, torrent_handle const& h
@@ -1649,8 +1645,6 @@ namespace libtorrent {
 		return msg;
 	}
 
-#ifndef TORRENT_DISABLE_LOGGING
-
 	log_alert::log_alert(aux::stack_allocator& alloc, char const* log)
 		: m_alloc(alloc)
 		, m_str_idx(alloc.copy_string(log))
@@ -1710,8 +1704,6 @@ namespace libtorrent {
 			+ mode[direction] + " " + event_type + " [ " + msg() + " ]";
 	}
 
-#endif
-
 	lsd_error_alert::lsd_error_alert(aux::stack_allocator&, error_code const& ec)
 		: alert()
 		, error(ec)
@@ -1881,24 +1873,19 @@ namespace libtorrent {
 		return ret;
 	}
 
-	// TODO: 3 use span<> here
 	dht_pkt_alert::dht_pkt_alert(aux::stack_allocator& alloc
-		, char const* buf, int size, dht_pkt_alert::direction_t d, udp::endpoint ep)
+		, span<char const> buf, dht_pkt_alert::direction_t d
+		, udp::endpoint const& ep)
 		: dir(d)
 		, node(std::move(ep))
 		, m_alloc(alloc)
-		, m_msg_idx(alloc.copy_buffer(buf, size))
-		, m_size(size)
+		, m_msg_idx(alloc.copy_buffer(buf))
+		, m_size(int(buf.size()))
 	{}
 
-	char const* dht_pkt_alert::pkt_buf() const
+	span<char const> dht_pkt_alert::pkt_buf() const
 	{
-		return m_alloc.get().ptr(m_msg_idx);
-	}
-
-	int dht_pkt_alert::pkt_size() const
-	{
-		return m_size;
+		return {m_alloc.get().ptr(m_msg_idx), size_t(m_size)};
 	}
 
 	std::string dht_pkt_alert::message() const
@@ -1908,7 +1895,8 @@ namespace libtorrent {
 
 		// ignore errors here. This is best-effort. It may be a broken encoding
 		// but at least we'll print the valid parts
-		bdecode(pkt_buf(), pkt_buf() + pkt_size(), print, ec, nullptr, 100, 100);
+		span<char const> pkt = pkt_buf();
+		bdecode(pkt.data(), pkt.data() + int(pkt.size()), print, ec, nullptr, 100, 100);
 
 		std::string msg = print_entry(print, true);
 
@@ -1940,7 +1928,7 @@ namespace libtorrent {
 			std::size_t size = endp.size();
 			TORRENT_ASSERT(size < 0x100);
 			detail::write_uint8(uint8_t(size), ptr);
-			memcpy(ptr, endp.data(), size);
+			std::memcpy(ptr, endp.data(), size);
 			ptr += size;
 		}
 	}
@@ -1972,7 +1960,7 @@ namespace libtorrent {
 		const char *ptr = m_alloc.get().ptr(m_peers_idx);
 		for (int i = 0; i < m_num_peers; i++) {
 			std::size_t size = detail::read_uint8(ptr);
-			memcpy(peers[i].data(), ptr, size);
+			std::memcpy(peers[i].data(), ptr, size);
 			ptr += size;
 		}
 
@@ -1983,8 +1971,7 @@ namespace libtorrent {
 		aux::stack_allocator& alloc, void* userdata_
 		, udp::endpoint const& addr_, bdecode_node const& response)
 		: userdata(userdata_), addr(addr_), m_alloc(alloc)
-		, m_response_idx(alloc.copy_buffer(response.data_section().data()
-				, int(response.data_section().size())))
+		, m_response_idx(alloc.copy_buffer(response.data_section()))
 		, m_response_size(int(response.data_section().size()))
 	{}
 
@@ -2017,27 +2004,25 @@ namespace libtorrent {
 		return ret;
 	}
 
-#ifndef TORRENT_DISABLE_LOGGING
-
 	picker_log_alert::picker_log_alert(aux::stack_allocator& alloc, torrent_handle const& h
 		, tcp::endpoint const& ep, peer_id const& peer_id, std::uint32_t flags
 		, piece_block const* blocks, int num_blocks)
 		: peer_alert(alloc, h, ep, peer_id)
 		, picker_flags(flags)
-		, m_array_idx(alloc.copy_buffer(reinterpret_cast<char const*>(blocks)
-			, num_blocks * sizeof(piece_block)))
+		, m_array_idx(alloc.copy_buffer({reinterpret_cast<char const*>(blocks)
+			, num_blocks * sizeof(piece_block)}))
 		, m_num_blocks(num_blocks)
 	{}
 
 	std::vector<piece_block> picker_log_alert::blocks() const
 	{
 		// we need to copy this array to make sure the structures are properly
-		// aigned, not just to have a nice API
+		// aligned, not just to have a nice API
 		std::vector<piece_block> ret;
 		ret.resize(m_num_blocks);
 
 		char const* start = m_alloc.get().ptr(m_array_idx);
-		memcpy(&ret[0], start, m_num_blocks * sizeof(piece_block));
+		std::memcpy(&ret[0], start, m_num_blocks * sizeof(piece_block));
 
 		return ret;
 	}
@@ -2088,6 +2073,4 @@ namespace libtorrent {
 		return ret;
 	}
 
-#endif // TORRENT_DISABLE_LOGGING
-
 } // namespace libtorrent
diff --git a/src/block_cache.cpp b/src/block_cache.cpp
index ad47c624e..7889b0f07 100644
--- a/src/block_cache.cpp
+++ b/src/block_cache.cpp
@@ -219,7 +219,7 @@ static_assert(sizeof(job_action_name)/sizeof(job_action_name[0])
 	== disk_io_job::num_job_ids, "disk-job-action and action-name-array mismatch");
 #endif
 
-#if TORRENT_USE_ASSERTS
+#if TORRENT_USE_ASSERTS || !defined TORRENT_DISABLE_LOGGING
 
 	char const* const piece_log_t::job_names[7] =
 	{
@@ -232,7 +232,7 @@ static_assert(sizeof(job_action_name)/sizeof(job_action_name[0])
 		"set_outstanding_jobs",
 	};
 
-	char const* job_name(int j)
+	char const* job_name(int const j)
 	{
 		if (j < 0 || j >= piece_log_t::last_job)
 			return "unknown";
@@ -242,6 +242,10 @@ static_assert(sizeof(job_action_name)/sizeof(job_action_name[0])
 		return piece_log_t::job_names[j - piece_log_t::flushing];
 	}
 
+#endif // TORRENT_DISABLE_LOGGING
+
+#if TORRENT_USE_ASSERTS
+
 	void print_piece_log(std::vector<piece_log_t> const& piece_log)
 	{
 		for (int i = 0; i < int(piece_log.size()); ++i)
diff --git a/src/kademlia/dht_tracker.cpp b/src/kademlia/dht_tracker.cpp
index 07b32e259..fe0a8332d 100644
--- a/src/kademlia/dht_tracker.cpp
+++ b/src/kademlia/dht_tracker.cpp
@@ -499,9 +499,6 @@ namespace libtorrent { namespace dht
 			return true;
 		}
 
-		using libtorrent::entry;
-		using libtorrent::bdecode;
-
 		TORRENT_ASSERT(buf_size > 0);
 
 		int pos;
@@ -511,7 +508,7 @@ namespace libtorrent { namespace dht
 		{
 			m_counters.inc_stats_counter(counters::dht_messages_in_dropped);
 #ifndef TORRENT_DISABLE_LOGGING
-			m_log->log_packet(dht_logger::incoming_message, buf.data(), buf_size, ep);
+			m_log->log_packet(dht_logger::incoming_message, buf, ep);
 #endif
 			return false;
 		}
@@ -519,14 +516,14 @@ namespace libtorrent { namespace dht
 		if (m_msg.type() != bdecode_node::dict_t)
 		{
 #ifndef TORRENT_DISABLE_LOGGING
-			m_log->log_packet(dht_logger::incoming_message, buf.data(), buf_size, ep);
+			m_log->log_packet(dht_logger::incoming_message, buf, ep);
 #endif
 			// it's not a good idea to send a response to an invalid messages
 			return false;
 		}
 
 #ifndef TORRENT_DISABLE_LOGGING
-		m_log->log_packet(dht_logger::incoming_message, buf.data(), buf_size, ep);
+		m_log->log_packet(dht_logger::incoming_message, buf, ep);
 #endif
 
 		libtorrent::dht::msg m(m_msg, ep);
@@ -605,10 +602,8 @@ namespace libtorrent { namespace dht
 		return m_send_quota > 0;
 	}
 
-	bool dht_tracker::send_packet(libtorrent::entry& e, udp::endpoint const& addr)
+	bool dht_tracker::send_packet(entry& e, udp::endpoint const& addr)
 	{
-		using libtorrent::bencode;
-
 		static char const version_str[] = {'L', 'T'
 			, LIBTORRENT_VERSION_MAJOR, LIBTORRENT_VERSION_MINOR};
 		e["v"] = std::string(version_str, version_str + 4);
@@ -627,8 +622,7 @@ namespace libtorrent { namespace dht
 		{
 			m_counters.inc_stats_counter(counters::dht_messages_out_dropped);
 #ifndef TORRENT_DISABLE_LOGGING
-			m_log->log_packet(dht_logger::outgoing_message, &m_send_buf[0]
-				, int(m_send_buf.size()), addr);
+			m_log->log_packet(dht_logger::outgoing_message, m_send_buf, addr);
 #endif
 			return false;
 		}
@@ -639,8 +633,7 @@ namespace libtorrent { namespace dht
 			, addr.address().is_v6() ? 48 : 28);
 		m_counters.inc_stats_counter(counters::dht_messages_out);
 #ifndef TORRENT_DISABLE_LOGGING
-		m_log->log_packet(dht_logger::outgoing_message, &m_send_buf[0]
-			, int(m_send_buf.size()), addr);
+		m_log->log_packet(dht_logger::outgoing_message, m_send_buf, addr);
 #endif
 		return true;
 	}
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 545f64e90..00139fa33 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -6671,7 +6671,7 @@ namespace aux {
 		va_end(v);
 	}
 
-	void session_impl::log_packet(message_direction_t dir, char const* pkt, int len
+	void session_impl::log_packet(message_direction_t dir, span<char const> pkt
 		, udp::endpoint const& node)
 	{
 		if (!m_alerts.should_post<dht_pkt_alert>()) return;
@@ -6679,7 +6679,7 @@ namespace aux {
 		dht_pkt_alert::direction_t d = dir == dht::dht_logger::incoming_message
 			? dht_pkt_alert::incoming : dht_pkt_alert::outgoing;
 
-		m_alerts.emplace_alert<dht_pkt_alert>(pkt, len, d, node);
+		m_alerts.emplace_alert<dht_pkt_alert>(pkt, d, node);
 	}
 
 	bool session_impl::should_log_portmap(aux::portmap_transport) const
diff --git a/test/test_dht.cpp b/test/test_dht.cpp
index 1e5363434..a89d20a9f 100644
--- a/test/test_dht.cpp
+++ b/test/test_dht.cpp
@@ -492,7 +492,7 @@ struct obs : dht::dht_observer
 		fprintf(stderr, "%s\n", buf);
 		m_log.push_back(buf);
 	}
-	void log_packet(message_direction_t dir, char const* pkt, int len
+	void log_packet(message_direction_t dir, span<char const> pkt
 		, udp::endpoint const& node) override {}
 #endif
 	bool on_dht_request(string_view query
diff --git a/test/test_dos_blocker.cpp b/test/test_dos_blocker.cpp
index 62d2a715a..5b6292755 100644
--- a/test/test_dos_blocker.cpp
+++ b/test/test_dos_blocker.cpp
@@ -56,12 +56,12 @@ struct log_t : libtorrent::dht::dht_logger
 		va_end(v);
 	}
 
-	void log_packet(message_direction_t dir, char const* pkt, int len
+	void log_packet(message_direction_t dir, span<char const> pkt
 		, udp::endpoint const& node) override
 	{
 		libtorrent::bdecode_node print;
 		libtorrent::error_code ec;
-		int ret = bdecode(pkt, pkt + len, print, ec, nullptr, 100, 100);
+		int ret = bdecode(pkt.data(), pkt.data() + int(pkt.size()), print, ec, nullptr, 100, 100);
 		TEST_EQUAL(ret, 0);
 
 		std::string msg = print_entry(print, true);