confirm.h

#ifndef __CONFIRM_H__
#define __CONFIRM_H__

/* the confirmation module receives queries to send packets toward
 * a destination with a given ttl, a given flow identifier, and
 * a maximum number of retransmissions.  when an answer is received
 * or after all retransmissions have timed out, a callback function
 * will be called informing the results. */

#include <inttypes.h>
#include "packet.h"

struct confirm_query {/*{{{*/
	int probe_type;

	/* query fields ******************/
	/* must be filled by the caller: */
	struct sockaddr_storage src; // check src.sa_family
	struct sockaddr_storage dst; // check dst.sa_family
	uint8_t ttl;

	union {
		/* `ip4_id` is not used to identify probes (in
		 * `confirm_query_cmp`) as it is not returned in
		 * `ECHO_REPLY` packets. */
		uint16_t ipid;
		struct {
			uint8_t traffic_class;
			uint32_t flow_label;
		};
	};

	union {
		struct {
			uint16_t src_port;
			uint16_t dst_port;
			uint32_t ack_number;
			uint8_t  control_flags;
			uint16_t window;
			uint16_t urgent_pointer;
		} tcp;

		uint16_t icmpid; /* icmpid == 0 fixes reverse flow id =revflow */
	};

	/*
	Note: for ICMP probes, the flowid goes into the checksum field
	      and it is in fact the flow identification of the probe,
	      for TCP probes, the flowid goes into the sequence number and it is
	      only the number of the probe used to match the response.
	*/
	uint8_t flowid;
	uint8_t revflow; /* reverse flow ID, ipv4 only, uses ipid */

	size_t padding; /* amount of zeroed bytes to append in the probe */

	int ntries;
	void (*cb)(struct confirm_query *query);
	void *data;

	/* answer fields *********************************/
	/* ip unset and trynum == ntries+1 if no answer: */
	int trynum;
	struct sockaddr_storage ip;

	struct timespec probetime;
	struct timespec timeout;
	struct timespec start;
	struct timespec lastpkt;
	struct timespec answertime;
	void *event;

	struct packet *probe;
	struct packet *response;
};/*}}}*/

struct confirm;
typedef void confirm_query_cb(struct confirm_query *query);

/* `confirm_create` will open a `libnet` sender on the given device
 * and wait for queries. */
struct confirm * confirm_create(const char *device);
void confirm_destroy(struct confirm *confirm);

void confirm_submit(struct confirm *confirm, struct confirm_query *query);

struct confirm_query * confirm_query_create4(
		const struct sockaddr_storage *src,
		const struct sockaddr_storage *dst,
		uint8_t ttl,
		uint16_t ipid,
		uint16_t icmpid, uint8_t flowid,
		uint8_t revflow,
		confirm_query_cb cb);

struct confirm_query * confirm_query_create6_icmp(
		const struct sockaddr_storage *src,
		const struct sockaddr_storage *dst,
		uint8_t ttl,
		uint8_t traffic_class, uint32_t flow_label,
		uint16_t icmpid, uint8_t flowid,
		confirm_query_cb cb);

struct confirm_query * confirm_query_create6_tcp(
		const struct sockaddr_storage *src,
		const struct sockaddr_storage *dst,
		uint8_t ttl,
		uint8_t traffic_class, uint32_t flow_label, uint8_t flowid,
		uint16_t src_port, uint16_t dst_port, uint32_t ack_number,
		uint8_t control_flags, uint16_t window, uint16_t urgent_pointer,
		confirm_query_cb cb);

void confirm_query_destroy(struct confirm_query *query);

#endif