[lwip-members] wildcard IPv4 address compare issue

[leon . woestenberg]

According to this macro, the wildcard IPv4 address 0.0.0.0 may be
indicated by a NULL pointer.

#define ip_addr_isany(addr1) ((addr1) == NULL || (addr1)->addr == 0)


However, comparing wildcard addresses will not work:

#define ip_addr_cmp(addr1, addr2) ((addr1)->addr == (addr2)->addr)

in these three cases:

add1  addr2
-------------------
0             NULL
NULL       0
NULL   NULL (it will work, but they reference illegal memory in most OSs)


We might fix the ip_addr_cmp() macro, or disallow NULL pointers for
wildcard.

Leon.