struct ip_addr undefined

[myrashidi]

Hey everybody,
making the latest code, having some errors on `struct ip_addr'
seems some files are missing on my system (Linux Ubuntu 20.04) or some package need to be installed that is not on my Ubuntu.
some erros I got:
session.c:45:13: error: dereferencing pointer to incomplete type ‘const struct ip_addr’
45 | b = ipaddr->addr.a4b;
session.c:66:6: error: conflicting types for ‘AddressToString’
66 | void AddressToString( const struct ip_addr ipaddr, uint16_t port, char buff )
session.c:117:25: error: storage size of ‘ip_dst’ isn’t known
117 | struct ip_addr ip_src, ip_dst;
| ^~~~~~

Any help would be appreciated.