diff --git a/src/layer1.h b/src/layer1.h
index 252bdf1..949194b 100644
--- a/src/layer1.h
+++ b/src/layer1.h
@@ -1,3 +1,9 @@
+#pragma once
+
+struct v5x_link;
+struct v5x_timeslot;
+struct v5x_interface;
+struct msgb;
 
 enum l1_signal_prim {
 	L1_SIGNAL_LOS,
diff --git a/src/v52_le_bcc_fsm.h b/src/v52_le_bcc_fsm.h
index 1e9819a..31a46b0 100644
--- a/src/v52_le_bcc_fsm.h
+++ b/src/v52_le_bcc_fsm.h
@@ -1,3 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+
+struct v52_bcc_proc;
+struct tlv_parsed;
+struct v5x_interface;
+enum v5x_mgmt_prim;
 
 void v52_le_bcc_destroy(struct v52_bcc_proc *bcc);
 void v52_le_bcc_init(void);
diff --git a/src/v52_le_lcp_fsm.h b/src/v52_le_lcp_fsm.h
index 01430e2..4866952 100644
--- a/src/v52_le_lcp_fsm.h
+++ b/src/v52_le_lcp_fsm.h
@@ -1,3 +1,11 @@
+#pragma once
+
+#include <osmocom/core/fsm.h>
+
+struct v5x_link;
+enum v5x_mph_prim;
+enum v5x_mgmt_prim;
+enum v52_link_ctrl_func;
 
 struct osmo_fsm_inst *v52_le_lcp_create(void *ctx, struct v5x_link *v5l, uint8_t id);
 void v52_le_lcp_destroy(struct osmo_fsm_inst *fi);
diff --git a/src/v52_le_pp_fsm.h b/src/v52_le_pp_fsm.h
index bc3bcdb..19ac7fd 100644
--- a/src/v52_le_pp_fsm.h
+++ b/src/v52_le_pp_fsm.h
@@ -1,3 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+
+struct v52_pp_proto;
+struct v5x_interface;
+struct v5x_link;
+struct tlv_parsed;
 
 struct v52_pp_proto *v52_le_pp_create(struct v5x_interface *v5if);
 void v52_le_pp_destroy(struct v52_pp_proto *pp);
diff --git a/src/v5le_vty.h b/src/v5le_vty.h
index 19c7c74..569602d 100644
--- a/src/v5le_vty.h
+++ b/src/v5le_vty.h
@@ -1,4 +1,6 @@
 #pragma once
 
+#include <osmocom/vty/vty.h>
+
 extern struct vty_app_info vty_info;
 int v5le_vty_init(void);
diff --git a/src/v5x_l1_fsm.h b/src/v5x_l1_fsm.h
index 8f2bc3f..d931f1d 100644
--- a/src/v5x_l1_fsm.h
+++ b/src/v5x_l1_fsm.h
@@ -1,3 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+
+struct v5x_link;
+enum v5x_mph_prim;
+struct v5x_l1_proto;
+enum l1_signal_prim;
 
 void v5x_l1_mph_snd(struct v5x_link *v5i, enum v5x_mph_prim prim);
 struct v5x_l1_proto *v5x_l1_fsm_create(void *ctx, struct v5x_link *v5l, uint8_t id);
diff --git a/src/v5x_le_ctrl_fsm.h b/src/v5x_le_ctrl_fsm.h
index ae4f124..8aa698f 100644
--- a/src/v5x_le_ctrl_fsm.h
+++ b/src/v5x_le_ctrl_fsm.h
@@ -1,3 +1,15 @@
+#pragma once
+
+#include <stdint.h>
+
+struct v5x_ctrl_proto;
+struct v5x_interface;
+struct v5x_user_port;
+enum v5x_ctrl_type;
+enum v5x_ctrl_func_id;
+enum v5x_ctrl_func_el;
+enum v52_link_ctrl_func;
+struct tlv_parsed;
 
 void v5x_le_ctrl_init(void);
 struct v5x_ctrl_proto *v5x_le_ctrl_create(enum v5x_ctrl_type type, void *ctx, void *priv, uint16_t nr);
diff --git a/src/v5x_le_management.h b/src/v5x_le_management.h
index 8ec84f8..39b808b 100644
--- a/src/v5x_le_management.h
+++ b/src/v5x_le_management.h
@@ -1,3 +1,14 @@
+#pragma once
+
+#include <stdint.h>
+
+struct osmo_fsm_inst;
+struct v5x_interface;
+struct v5x_mgmt_proto;
+struct v5x_link;
+struct v5x_user_port;
+enum v5x_mgmt_prim;
+struct msgb;
 
 const char *v5x_le_system_fsm_state_name(struct osmo_fsm_inst *fi);
 const char *v5x_le_pstn_dl_fsm_state_name(struct osmo_fsm_inst *fi);
diff --git a/src/v5x_le_port_fsm.h b/src/v5x_le_port_fsm.h
index db068a8..40ed87c 100644
--- a/src/v5x_le_port_fsm.h
+++ b/src/v5x_le_port_fsm.h
@@ -1,3 +1,10 @@
+#pragma once
+
+#include <stdint.h>
+
+struct v5x_user_port;
+enum v5x_mph_prim;
+struct osmo_fsm_inst;
 
 void v5x_port_mph_snd(struct v5x_user_port *v5up, enum v5x_mph_prim prim);
 
diff --git a/src/v5x_le_pstn_fsm.h b/src/v5x_le_pstn_fsm.h
index a0df6bf..68be974 100644
--- a/src/v5x_le_pstn_fsm.h
+++ b/src/v5x_le_pstn_fsm.h
@@ -1,3 +1,15 @@
+#pragma once
+
+#include <stdint.h>
+
+struct v5x_pstn_proto;
+struct v5x_user_port;
+struct v5x_l1_proto;
+struct v5x_user_port;
+enum v5x_fe_prim;
+enum v5x_mgmt_prim;
+struct msgb;
+struct tlv_parsed;
 
 struct v5x_pstn_proto *v5x_le_pstn_create(struct v5x_user_port *v5up, uint16_t nr);
 void v5x_le_pstn_destroy(struct v5x_pstn_proto *pstn);