void port_set(struct sockaddr *sa, uint16_t port);
void printfchars(char *prefixfmt, char *prefix, char *charfmt, char *chars, int len);
+void disable_DF_bit(int socket, struct addrinfo *res);
int bindtoaddr(struct addrinfo *addrinfo, int family, int reuse, int v6only);
int connecttcp(struct addrinfo *addrinfo, struct addrinfo *src, uint16_t timeout);