diff --git a/http2/frame.go b/http2/frame.go
index b95d6f2..96a7479 100644
--- a/http2/frame.go
+++ b/http2/frame.go
@@ -122,7 +122,7 @@
 // a frameParser parses a frame given its FrameHeader and payload
 // bytes. The length of payload will always equal fh.Length (which
 // might be 0).
-type frameParser func(fc *frameCache, fh FrameHeader, payload []byte) (Frame, error)
+type frameParser func(fc *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error)
 
 var frameParsers = map[FrameType]frameParser{
 	FrameData:         parseDataFrame,
@@ -267,6 +267,11 @@
 	lastFrame Frame
 	errDetail error
 
+	// countError is a non-nil func that's called on a frame parse
+	// error with some unique error path token. It's initialized
+	// from Transport.CountError or Server.CountError.
+	countError func(errToken string)
+
 	// lastHeaderStream is non-zero if the last frame was an
 	// unfinished HEADERS/CONTINUATION.
 	lastHeaderStream uint32
@@ -426,6 +431,7 @@
 	fr := &Framer{
 		w:                 w,
 		r:                 r,
+		countError:        func(string) {},
 		logReads:          logFrameReads,
 		logWrites:         logFrameWrites,
 		debugReadLoggerf:  log.Printf,
@@ -500,7 +506,7 @@
 	if _, err := io.ReadFull(fr.r, payload); err != nil {
 		return nil, err
 	}
-	f, err := typeFrameParser(fh.Type)(fr.frameCache, fh, payload)
+	f, err := typeFrameParser(fh.Type)(fr.frameCache, fh, fr.countError, payload)
 	if err != nil {
 		if ce, ok := err.(connError); ok {
 			return nil, fr.connError(ce.Code, ce.Reason)
@@ -588,13 +594,14 @@
 	return f.data
 }
 
-func parseDataFrame(fc *frameCache, fh FrameHeader, payload []byte) (Frame, error) {
+func parseDataFrame(fc *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error) {
 	if fh.StreamID == 0 {
 		// DATA frames MUST be associated with a stream. If a
 		// DATA frame is received whose stream identifier
 		// field is 0x0, the recipient MUST respond with a
 		// connection error (Section 5.4.1) of type
 		// PROTOCOL_ERROR.
+		countError("frame_data_stream_0")
 		return nil, connError{ErrCodeProtocol, "DATA frame with stream ID 0"}
 	}
 	f := fc.getDataFrame()
@@ -605,6 +612,7 @@
 		var err error
 		payload, padSize, err = readByte(payload)
 		if err != nil {
+			countError("frame_data_pad_byte_short")
 			return nil, err
 		}
 	}
@@ -613,6 +621,7 @@
 		// length of the frame payload, the recipient MUST
 		// treat this as a connection error.
 		// Filed: https://github.com/http2/http2-spec/issues/610
+		countError("frame_data_pad_too_big")
 		return nil, connError{ErrCodeProtocol, "pad size larger than data payload"}
 	}
 	f.data = payload[:len(payload)-int(padSize)]
@@ -695,7 +704,7 @@
 	p []byte
 }
 
-func parseSettingsFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
+func parseSettingsFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
 	if fh.Flags.Has(FlagSettingsAck) && fh.Length > 0 {
 		// When this (ACK 0x1) bit is set, the payload of the
 		// SETTINGS frame MUST be empty. Receipt of a
@@ -703,6 +712,7 @@
 		// field value other than 0 MUST be treated as a
 		// connection error (Section 5.4.1) of type
 		// FRAME_SIZE_ERROR.
+		countError("frame_settings_ack_with_length")
 		return nil, ConnectionError(ErrCodeFrameSize)
 	}
 	if fh.StreamID != 0 {
@@ -713,14 +723,17 @@
 		// field is anything other than 0x0, the endpoint MUST
 		// respond with a connection error (Section 5.4.1) of
 		// type PROTOCOL_ERROR.
+		countError("frame_settings_has_stream")
 		return nil, ConnectionError(ErrCodeProtocol)
 	}
 	if len(p)%6 != 0 {
+		countError("frame_settings_mod_6")
 		// Expecting even number of 6 byte settings.
 		return nil, ConnectionError(ErrCodeFrameSize)
 	}
 	f := &SettingsFrame{FrameHeader: fh, p: p}
 	if v, ok := f.Value(SettingInitialWindowSize); ok && v > (1<<31)-1 {
+		countError("frame_settings_window_size_too_big")
 		// Values above the maximum flow control window size of 2^31 - 1 MUST
 		// be treated as a connection error (Section 5.4.1) of type
 		// FLOW_CONTROL_ERROR.
@@ -832,11 +845,13 @@
 
 func (f *PingFrame) IsAck() bool { return f.Flags.Has(FlagPingAck) }
 
-func parsePingFrame(_ *frameCache, fh FrameHeader, payload []byte) (Frame, error) {
+func parsePingFrame(_ *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error) {
 	if len(payload) != 8 {
+		countError("frame_ping_length")
 		return nil, ConnectionError(ErrCodeFrameSize)
 	}
 	if fh.StreamID != 0 {
+		countError("frame_ping_has_stream")
 		return nil, ConnectionError(ErrCodeProtocol)
 	}
 	f := &PingFrame{FrameHeader: fh}
@@ -872,11 +887,13 @@
 	return f.debugData
 }
 
-func parseGoAwayFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
+func parseGoAwayFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
 	if fh.StreamID != 0 {
+		countError("frame_goaway_has_stream")
 		return nil, ConnectionError(ErrCodeProtocol)
 	}
 	if len(p) < 8 {
+		countError("frame_goaway_short")
 		return nil, ConnectionError(ErrCodeFrameSize)
 	}
 	return &GoAwayFrame{
@@ -912,7 +929,7 @@
 	return f.p
 }
 
-func parseUnknownFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
+func parseUnknownFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
 	return &UnknownFrame{fh, p}, nil
 }
 
@@ -923,8 +940,9 @@
 	Increment uint32 // never read with high bit set
 }
 
-func parseWindowUpdateFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
+func parseWindowUpdateFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
 	if len(p) != 4 {
+		countError("frame_windowupdate_bad_len")
 		return nil, ConnectionError(ErrCodeFrameSize)
 	}
 	inc := binary.BigEndian.Uint32(p[:4]) & 0x7fffffff // mask off high reserved bit
@@ -936,8 +954,10 @@
 		// control window MUST be treated as a connection
 		// error (Section 5.4.1).
 		if fh.StreamID == 0 {
+			countError("frame_windowupdate_zero_inc_conn")
 			return nil, ConnectionError(ErrCodeProtocol)
 		}
+		countError("frame_windowupdate_zero_inc_stream")
 		return nil, streamError(fh.StreamID, ErrCodeProtocol)
 	}
 	return &WindowUpdateFrame{
@@ -988,7 +1008,7 @@
 	return f.FrameHeader.Flags.Has(FlagHeadersPriority)
 }
 
-func parseHeadersFrame(_ *frameCache, fh FrameHeader, p []byte) (_ Frame, err error) {
+func parseHeadersFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (_ Frame, err error) {
 	hf := &HeadersFrame{
 		FrameHeader: fh,
 	}
@@ -997,11 +1017,13 @@
 		// is received whose stream identifier field is 0x0, the recipient MUST
 		// respond with a connection error (Section 5.4.1) of type
 		// PROTOCOL_ERROR.
+		countError("frame_headers_zero_stream")
 		return nil, connError{ErrCodeProtocol, "HEADERS frame with stream ID 0"}
 	}
 	var padLength uint8
 	if fh.Flags.Has(FlagHeadersPadded) {
 		if p, padLength, err = readByte(p); err != nil {
+			countError("frame_headers_pad_short")
 			return
 		}
 	}
@@ -1009,16 +1031,19 @@
 		var v uint32
 		p, v, err = readUint32(p)
 		if err != nil {
+			countError("frame_headers_prio_short")
 			return nil, err
 		}
 		hf.Priority.StreamDep = v & 0x7fffffff
 		hf.Priority.Exclusive = (v != hf.Priority.StreamDep) // high bit was set
 		p, hf.Priority.Weight, err = readByte(p)
 		if err != nil {
+			countError("frame_headers_prio_weight_short")
 			return nil, err
 		}
 	}
 	if len(p)-int(padLength) < 0 {
+		countError("frame_headers_pad_too_big")
 		return nil, streamError(fh.StreamID, ErrCodeProtocol)
 	}
 	hf.headerFragBuf = p[:len(p)-int(padLength)]
@@ -1125,11 +1150,13 @@
 	return p == PriorityParam{}
 }
 
-func parsePriorityFrame(_ *frameCache, fh FrameHeader, payload []byte) (Frame, error) {
+func parsePriorityFrame(_ *frameCache, fh FrameHeader, countError func(string), payload []byte) (Frame, error) {
 	if fh.StreamID == 0 {
+		countError("frame_priority_zero_stream")
 		return nil, connError{ErrCodeProtocol, "PRIORITY frame with stream ID 0"}
 	}
 	if len(payload) != 5 {
+		countError("frame_priority_bad_length")
 		return nil, connError{ErrCodeFrameSize, fmt.Sprintf("PRIORITY frame payload size was %d; want 5", len(payload))}
 	}
 	v := binary.BigEndian.Uint32(payload[:4])
@@ -1172,11 +1199,13 @@
 	ErrCode ErrCode
 }
 
-func parseRSTStreamFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
+func parseRSTStreamFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
 	if len(p) != 4 {
+		countError("frame_rststream_bad_len")
 		return nil, ConnectionError(ErrCodeFrameSize)
 	}
 	if fh.StreamID == 0 {
+		countError("frame_rststream_zero_stream")
 		return nil, ConnectionError(ErrCodeProtocol)
 	}
 	return &RSTStreamFrame{fh, ErrCode(binary.BigEndian.Uint32(p[:4]))}, nil
@@ -1202,8 +1231,9 @@
 	headerFragBuf []byte
 }
 
-func parseContinuationFrame(_ *frameCache, fh FrameHeader, p []byte) (Frame, error) {
+func parseContinuationFrame(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (Frame, error) {
 	if fh.StreamID == 0 {
+		countError("frame_continuation_zero_stream")
 		return nil, connError{ErrCodeProtocol, "CONTINUATION frame with stream ID 0"}
 	}
 	return &ContinuationFrame{fh, p}, nil
@@ -1252,7 +1282,7 @@
 	return f.FrameHeader.Flags.Has(FlagPushPromiseEndHeaders)
 }
 
-func parsePushPromise(_ *frameCache, fh FrameHeader, p []byte) (_ Frame, err error) {
+func parsePushPromise(_ *frameCache, fh FrameHeader, countError func(string), p []byte) (_ Frame, err error) {
 	pp := &PushPromiseFrame{
 		FrameHeader: fh,
 	}
@@ -1263,6 +1293,7 @@
 		// with. If the stream identifier field specifies the value
 		// 0x0, a recipient MUST respond with a connection error
 		// (Section 5.4.1) of type PROTOCOL_ERROR.
+		countError("frame_pushpromise_zero_stream")
 		return nil, ConnectionError(ErrCodeProtocol)
 	}
 	// The PUSH_PROMISE frame includes optional padding.
@@ -1270,18 +1301,21 @@
 	var padLength uint8
 	if fh.Flags.Has(FlagPushPromisePadded) {
 		if p, padLength, err = readByte(p); err != nil {
+			countError("frame_pushpromise_pad_short")
 			return
 		}
 	}
 
 	p, pp.PromiseID, err = readUint32(p)
 	if err != nil {
+		countError("frame_pushpromise_promiseid_short")
 		return
 	}
 	pp.PromiseID = pp.PromiseID & (1<<31 - 1)
 
 	if int(padLength) > len(p) {
 		// like the DATA frame, error out if padding is longer than the body.
+		countError("frame_pushpromise_pad_too_big")
 		return nil, ConnectionError(ErrCodeProtocol)
 	}
 	pp.headerFragBuf = p[:len(p)-int(padLength)]
diff --git a/http2/server.go b/http2/server.go
index d986655..1caab32 100644
--- a/http2/server.go
+++ b/http2/server.go
@@ -411,6 +411,9 @@
 	sc.hpackEncoder = hpack.NewEncoder(&sc.headerWriteBuf)
 
 	fr := NewFramer(sc.bw, c)
+	if s.CountError != nil {
+		fr.countError = s.CountError
+	}
 	fr.ReadMetaHeaders = hpack.NewDecoder(initialHeaderTableSize, nil)
 	fr.MaxHeaderListSize = sc.maxHeaderListSize()
 	fr.SetMaxReadFrameSize(s.maxReadFrameSize())
diff --git a/http2/transport.go b/http2/transport.go
index 1fb565f..94e0bef 100644
--- a/http2/transport.go
+++ b/http2/transport.go
@@ -699,6 +699,9 @@
 	cc.bw = bufio.NewWriter(stickyErrWriter{c, &cc.werr})
 	cc.br = bufio.NewReader(c)
 	cc.fr = NewFramer(cc.bw, cc.br)
+	if t.CountError != nil {
+		cc.fr.countError = t.CountError
+	}
 	cc.fr.ReadMetaHeaders = hpack.NewDecoder(initialHeaderTableSize, nil)
 	cc.fr.MaxHeaderListSize = t.maxHeaderListSize()