File syn_icmp.c

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Zero-Heap Native ICMP Protocol Engine Implementation.

• #include "syntropic/net/syn_icmp.h"
• #include <string.h>

Public Functions

Type	Name
SYN_Status	syn_icmp_build_echo_request (SYN_ICMP * icmp, SYN_ETH * eth, uint32_t dst_ip, const uint8_t dst_mac, uint16_t id, uint16_t seq, const uint8_t * payload, size_t payload_len, uint8_t * frame_out, size_t * frame_len) Construct an outbound ICMP Echo Request frame.
uint16_t	syn_icmp_checksum (const void * buf, size_t len) Compute RFC 1071 Ones-Complement Internet Checksum.
SYN_Status	syn_icmp_init (SYN_ICMP * icmp) Initialize ICMP Engine Context.
SYN_Status	syn_icmp_process_packet (SYN_ICMP * icmp, const uint8_t * ip_pkt, size_t len, uint8_t * frame_tx, size_t * tx_len) Process incoming ICMP packet inside IPv4 payload.

Public Functions Documentation

function syn_icmp_build_echo_request

Construct an outbound ICMP Echo Request frame.

SYN_Status syn_icmp_build_echo_request (
    SYN_ICMP * icmp,
    SYN_ETH * eth,
    uint32_t dst_ip,
    const uint8_t dst_mac,
    uint16_t id,
    uint16_t seq,
    const uint8_t * payload,
    size_t payload_len,
    uint8_t * frame_out,
    size_t * frame_len
) 

Parameters:

• icmp Pointer to ICMP context.
• eth Pointer to Ethernet context.
• dst_ip 32-bit IPv4 address of destination.
• dst_mac 6-byte MAC address of destination.
• id Identifier.
• seq Sequence number.
• payload Pointer to payload data.
• payload_len Payload length in bytes.
• frame_out Output frame buffer (must hold at least 60 bytes).
• frame_len Pointer to receive final Ethernet II frame length.

Returns:

SYN_OK on success.

---

function syn_icmp_checksum

Compute RFC 1071 Ones-Complement Internet Checksum.

uint16_t syn_icmp_checksum (
    const void * buf,
    size_t len
) 

Parameters:

• buf Pointer to buffer bytes.
• len Length in bytes.

Returns:

16-bit Ones-Complement checksum.

---

function syn_icmp_init

Initialize ICMP Engine Context.

SYN_Status syn_icmp_init (
    SYN_ICMP * icmp
) 

Parameters:

• icmp Pointer to ICMP context.

Returns:

SYN_OK on success.

---

function syn_icmp_process_packet

Process incoming ICMP packet inside IPv4 payload.

SYN_Status syn_icmp_process_packet (
    SYN_ICMP * icmp,
    const uint8_t * ip_pkt,
    size_t len,
    uint8_t * frame_tx,
    size_t * tx_len
) 

Automatically generates a matching Type 0 Echo Reply if a Type 8 Echo Request is received.

Parameters:

• icmp Pointer to ICMP context.
• ip_pkt Pointer to incoming IPv4 packet (starting at IP header).
• len IP packet byte length.
• frame_tx Output buffer to receive constructed Ethernet II reply frame (min 60 bytes).
• tx_len Pointer to receive byte length of constructed reply frame (0 if none generated).

Returns:

SYN_OK on success.

---

---

The documentation for this class was generated from the following file src/syntropic/net/syn_icmp.c