diff --git a/src/diag_log.c b/src/diag_log.c
new file mode 100644
index 0000000..1bb3a72
--- /dev/null
+++ b/src/diag_log.c
@@ -0,0 +1,143 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <osmocom/core/msgb.h>
+
+#include "diag_log.h"
+#include "protocol.h"
+#include "diagcmd.h"
+
+/***********************************************************************
+ * LOG Configuration / Protocol
+ ***********************************************************************/
+
+enum log_config_op {
+	LOG_CONFIG_DISABLE_OP			= 0,
+	LOG_CONFIG_RETRIEVE_ID_RANGES_OP	= 1,
+	LOG_CONFIG_RETRIEVE_VALID_MASK_OP	= 2,
+	LOG_CONFIG_SET_MASK_OP			= 3,
+	LOG_CONFIG_GET_LOGMASK_OP		= 4,
+};
+
+struct diag_log_config_req_hdr {
+	uint8_t		msg_type;
+	uint8_t		pad[3];
+	uint32_t	operation;
+} __attribute((packed));
+
+struct diag_log_config_set_mask {
+	struct diag_log_config_req_hdr hdr;
+	uint32_t	equip_id;
+	uint32_t	last_item;
+	uint8_t		data[0];
+} __attribute((packed));
+
+struct msgb *gen_log_config_set_mask(uint32_t equip_id, uint32_t last_item)
+{
+	struct msgb *msg = msgb_alloc(DIAG_MAX_REQ_SIZE, "Diag Tx");
+	struct diag_log_config_set_mask *dlcsm;
+
+	msg->l2h = msgb_put(msg, sizeof(*dlcsm));
+	dlcsm = (struct diag_log_config_set_mask *) msg->l2h;
+	dlcsm->hdr.msg_type = DIAG_LOG_CONFIG_F;
+	dlcsm->hdr.operation = LOG_CONFIG_SET_MASK_OP;
+	dlcsm->equip_id = equip_id;
+	dlcsm->last_item = last_item;
+	msg->l3h = msgb_put(msg, dlcsm->last_item/8);
+
+	return msg;
+}
+
+int log_config_set_mask_bit(struct msgb *msg, uint32_t bit_in)
+{
+	struct diag_log_config_set_mask *dlcsm;
+	dlcsm = (struct diag_log_config_set_mask *) msg->l2h;
+	uint8_t *mask = msg->l3h;
+	unsigned int byte = bit_in / 8;
+	unsigned int bit = bit_in % 8;
+
+	if (byte > dlcsm->last_item/8)
+		return -1;
+
+	mask[byte] |= (1 << bit);
+
+	return 0;
+}
+
+
+/***********************************************************************
+ * LOG Dispatch
+ ***********************************************************************/
+
+/* not particularly memory efficient, but welll, only 500kB on 64bit */
+static diag_log_handler *log_handlers[0xffff];
+
+/* called by individual modules to register their own decoders */
+void diag_log_reg_dispatch(const struct diag_log_dispatch_tbl *tbl, unsigned int size)
+{
+	unsigned int i;
+	for (i = 0; i < size; i++) {
+		printf("Registering dispatch for 0x%04x\n", tbl[i].code);
+		log_handlers[tbl[i].code] = tbl[i].handler;
+	}
+}
+
+void diag_log_enable_all_supported_family(struct diag_instance *di, uint8_t family)
+{
+	struct msgb *msg;
+	unsigned int i, size;
+	unsigned int family_base = (family & 0xf) << 12;
+	unsigned int max = 0;
+
+	for (i = family_base; i < family_base + 0x1000; i++) {
+		if (log_handlers[i]) {
+			if (max < i)
+				max = i;
+		}
+	}
+
+	if (!max)
+		return;
+
+	size = max - family_base;
+	printf("family %u: allocating log mask of size %u\n", family, size);
+	msg = gen_log_config_set_mask(family, size);
+	for (i = family_base; i < family_base + 0x1000; i++) {
+		if (log_handlers[i])
+			log_config_set_mask_bit(msg, i-family_base);
+	}
+
+	diag_transmit_msgb(di, msg);
+	diag_read(di);
+}
+
+void diag_log_enable_all_supported(struct diag_instance *di)
+{
+	unsigned int i;
+
+	for (i = 0; i < 0xF; i++) {
+		diag_log_enable_all_supported_family(di, i);
+	}
+}
+
+void diag_log_handle(struct diag_instance *di, struct msgb *msg)
+{
+	struct diag_log_hdr *dlh;
+	struct log_hdr *lh;
+
+	dlh = (struct diag_log_hdr *) msg->data;
+	/* FIXME: verify length */
+	msg->l3h = msgb_pull(msg, sizeof(*dlh));
+
+	lh = (struct log_hdr *) msg->l3h;
+	/* FIXME: verify length */
+	msgb_pull(msg, sizeof(*lh));
+
+	printf("LOG(0x%04x|%u|%u): ", lh->code,
+		diag_ts_to_epoch(lh->ts), diag_ts_to_fn(lh->ts));
+
+	if (log_handlers[lh->code])
+		log_handlers[lh->code](lh, msg);
+	else
+		printf("%s\n", osmo_hexdump(lh->data, lh->len));
+}