first commit

src/icmp.h

@@ -0,0 +1,14 @@
+#include <stddef.h>
+#include "defs.h"
+
+typedef struct {
+    void  *output_ptr;
+    size_t output_len;
+    void *send_data;
+    void (*send)(void *send_data, ip_address_t ip, size_t len);
+} icmp_state_t;
+
+void icmp_init(icmp_state_t *state, void *send_data, void (*send)(void*, ip_address_t, size_t));
+void icmp_free(icmp_state_t *state);
+void icmp_process_packet(icmp_state_t *state, ip_address_t ip, const void *src, size_t len);
+void icmp_change_output_buffer(icmp_state_t *state, void *ptr, size_t len);