class IpHeader4

IPv4 packet header. More...

 
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Detailed Description

The IPv4 packet header has the following content:

ip_vhl (1 byte): // IP ver/hdrlen (version << 4 | header length >> 2) ip_tos (1 byte): // Type of service ip_len (2 bytes): // Total length ip_id (2 bytes): // Identification ip_off (2 bytes): // Fragment offset field (least-significant 13 bits) ip_ttl (1 byte): // Time to live ip_p (1 byte): // Protocol ip_sum (2 bytes): // Checksum ip_src (4 bytes): // Source address ip_dst (4 bytes): // Destination address

 IpHeader4 (const uint8_t* data)

IpHeader4

static const size_t SIZE

SIZE

static const uint8_t IP_VERSION

IP_VERSION

size_t  size ()

size

[static]

Get the IPv4 packet header size.

Note that this is the header size only without any header options.

Returns: the IPv4 packet header size.

const uint8_t*  data ()

data

[const]

Get the buffer data.

Returns: the buffer data.

uint8_t  ip_vhl ()

ip_vhl

[const]

Methods to get various IP header fields.

uint8_t  ip_tos ()

ip_tos

[const]

uint16_t  ip_len ()

ip_len

[const]

uint16_t  ip_id ()

ip_id

[const]

uint16_t  ip_off ()

ip_off

[const]

uint8_t  ip_ttl ()

ip_ttl

[const]

uint8_t  ip_p ()

ip_p

[const]

uint16_t  ip_sum ()

ip_sum

[const]

IPv4  ip_src ()

ip_src

[const]

IPv4  ip_dst ()

ip_dst

[const]

uint16_t  ip_len_host ()

ip_len_host

[const]

uint8_t  ip_version ()

ip_version

[const]

Get the IP protocol version of the header.

Returns: the IP protocol version of the header.

uint8_t  ip_header_len ()

ip_header_len

[const]

Get the IPv4 packet header size (including any header options).

Returns: the IPv4 packet header size (including any header options).

uint16_t  ip_fragment_offset ()

ip_fragment_offset

[const]

Get the IPv4 fragment offset (excluding the fragment flags).

Returns: the IPv4 fragment offset (excluding the fragment flags).

uint16_t  ip_fragment_flags ()

ip_fragment_flags

[const]

Get the IPv4 fragment flags.

Returns: the IPv4 fragment flags.

bool  is_valid_version ()

is_valid_version

[const]

Test whether the IP header version is valid.

Returns: true if the IP header version is valid, otherwise false.

int  fragment (size_t mtu, list<vector<uint8_t> >& fragments, bool do_checksum, string& error_msg)

fragment

[const]

Fragment an IPv4 packet.

Note: If the original packet is not larger than the MTU, then the packet is not fragmented (i.e., fragments is empty), and the return value is XORP_OK.

Parameters:

mtuthe MTU for fragmenting the packet.
fragmentsthe return-by-reference fragments of the IPv4 packet.
do_checksumif true, compute and set the checksum in the IPv4 header, otherwise reset it to zero.
error_msgthe error message (if error).

Returns: XORP_OK on success, otherwise XORP_ERROR.

static const uint16_t FRAGMENT_OFFSET_MASK

FRAGMENT_OFFSET_MASK

[protected]

static const uint16_t FRAGMENT_FLAGS_MASK

FRAGMENT_FLAGS_MASK

[protected]

static const uint16_t FRAGMENT_FLAGS_IP_DF

FRAGMENT_FLAGS_IP_DF

[protected]

static const uint16_t FRAGMENT_FLAGS_IP_MF

FRAGMENT_FLAGS_IP_MF

[protected]

static const uint8_t OPTIONS_IPOPT_EOL

OPTIONS_IPOPT_EOL

[protected]

static const uint8_t OPTIONS_IPOPT_NOP

OPTIONS_IPOPT_NOP

[protected]

static const size_t OPTIONS_IPOPT_OLEN

OPTIONS_IPOPT_OLEN

[protected]

static const uint8_t OPTIONS_COPIED_FLAG

OPTIONS_COPIED_FLAG

[protected]

static const size_t _ip_vhl_sizeof

_ip_vhl_sizeof

[protected]

static const size_t _ip_tos_sizeof

_ip_tos_sizeof

[protected]

static const size_t _ip_len_sizeof

_ip_len_sizeof

[protected]

static const size_t _ip_id_sizeof

_ip_id_sizeof

[protected]

static const size_t _ip_off_sizeof

_ip_off_sizeof

[protected]

static const size_t _ip_ttl_sizeof

_ip_ttl_sizeof

[protected]

static const size_t _ip_p_sizeof

_ip_p_sizeof

[protected]

static const size_t _ip_sum_sizeof

_ip_sum_sizeof

[protected]

static const size_t _ip_src_sizeof

_ip_src_sizeof

[protected]

static const size_t _ip_dst_sizeof

_ip_dst_sizeof

[protected]

static const size_t _ip_vhl_offset

_ip_vhl_offset

[protected]

static const size_t _ip_tos_offset

_ip_tos_offset

[protected]

static const size_t _ip_len_offset

_ip_len_offset

[protected]

static const size_t _ip_id_offset

_ip_id_offset

[protected]

static const size_t _ip_off_offset

_ip_off_offset

[protected]

static const size_t _ip_ttl_offset

_ip_ttl_offset

[protected]

static const size_t _ip_p_offset

_ip_p_offset

[protected]

static const size_t _ip_sum_offset

_ip_sum_offset

[protected]

static const size_t _ip_src_offset

_ip_src_offset

[protected]

static const size_t _ip_dst_offset

_ip_dst_offset

[protected]


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