void err(const char *format, ...);
void warn(const char *format, ...);
void info(const char *format, ...);

#ifdef DEBUG
void debug(const char *format, ...);
#else
#define debug(...) { }
#endif

#define CHECK_SET_MIN_MAX(basename, fd)					\
	do {								\
		if ((fd) < basename##min)				\
			basename##min = (fd);				\
		if ((fd) > basename##max)				\
			basename##max = (fd);				\
	} while (0)

#define CHECK_SET_MIN_MAX_PROTO_FD(proto, ipproto, proto_ctx, fd)	\
	do {								\
		if ((proto) == (ipproto))				\
			CHECK_SET_MIN_MAX(c->proto_ctx.fd_, (fd));	\
	} while (0)

#define MIN(x, y)		(((x) < (y)) ? (x) : (y))

#define IN_INTERVAL(a, b, x)	((x) >= (a) && (x) <= (b))

#define FD_PROTO(x, proto)						\
	(IN_INTERVAL(c->proto.fd_min, c->proto.fd_max, (x)))

#define PORT_IS_EPHEMERAL(port) ((port) >= (1 << 15) + (1 << 14)) /* RFC 6335 */

uint16_t csum_fold(uint32_t sum);
uint16_t csum_ip4(void *buf, size_t len);
void csum_tcp4(struct iphdr *iph);
char *ipv6_l4hdr(struct ipv6hdr *ip6h, uint8_t *proto);
int sock_l4(struct ctx *c, int af, uint16_t proto, uint16_t port);
int timespec_diff_ms(struct timespec *a, struct timespec *b);