str_ipproto
(*pr)("IP: protocol = %u(%s)\n", ip.ip_p, str_ipproto(ip.ip_p));
static const char *str_ipproto(const uint8_t);
(*pr)("IPv6: Next Header = %u(%s)\n", nxt, str_ipproto(nxt));
(*pr)("IPv6: Next Header = %u(%s)\n", nxt, str_ipproto(nxt));