comp/schemes/ip_id_offset.c File Reference

Offset IP-ID encoding. More...

#include "ip_id_offset.h"
#include "ip.h"

Include dependency graph for comp/schemes/ip_id_offset.c:

Functions
bool	is_ip_id_increasing (const uint16_t old_id, const uint16_t new_id, const uint16_t max_delta)
	Whether the new IP-ID is increasing. More...
rohc_ip_id_behavior_t	rohc_comp_detect_ip_id_behavior (const uint16_t last_ip_id, const uint16_t new_ip_id, const int32_t msn_offset, const uint16_t max_delta)
	Detect the behavior of the IPv4 Identification field. More...

Detailed Description

Offset IP-ID encoding.

Author

Didier Barvaux didie.nosp@m.r@ba.nosp@m.rvaux.nosp@m..org

Function Documentation

is_ip_id_increasing()

bool is_ip_id_increasing	(	const uint16_t	old_id,
		const uint16_t	new_id,
		const uint16_t	max_delta
	)

Whether the new IP-ID is increasing.

The new IP-ID is considered as increasing if the new value is greater by a small delta then the previous IP-ID. Wraparound shall be taken into account.

Parameters

old_id	The IP-ID of the previous IPv4 header
new_id	The IP-ID of the current IPv4 header
max_delta	The maximum allowed delta

Returns

Whether the IP-ID is increasing

rohc_comp_detect_ip_id_behavior()

rohc_ip_id_behavior_t rohc_comp_detect_ip_id_behavior	(	const uint16_t	last_ip_id,
		const uint16_t	new_ip_id,
		const int32_t	msn_offset,
		const uint16_t	max_delta
	)

Detect the behavior of the IPv4 Identification field.

Parameters

last_ip_id	The IP-ID value of the previous packet (in HBO)
new_ip_id	The IP-ID value of the current packet (in HBO)
msn_offset	The offset between the previous and current MSN
max_delta	The maximum allowed delta

Returns

The IP-ID behavior among: ROHC_IP_ID_BEHAVIOR_SEQ, ROHC_IP_ID_BEHAVIOR_SEQ_SWAP, ROHC_IP_ID_BEHAVIOR_ZERO, or ROHC_IP_ID_BEHAVIOR_RAND