3.1 KiB
libicmp
Non-blocking ICMPv4 library for building ping, traceroute, and network diagnostic tools.
Dependencies
- libc
- GNU make
- clang
- POSIX-compliant OS
For tests only:
- criterion
Build
make # Build static and shared libraries
make BUILD_STATIC=yes BUILD_SHARED=no
make install PREFIX=/usr/local
make test
API
Handle lifecycle
icmp_handle_t *icmp_create(void);
void icmp_destroy(icmp_handle_t *h);
int icmp_get_fd(const icmp_handle_t *h);
icmp_create() opens a raw ICMP socket and returns an opaque handle.
icmp_get_fd() exposes the underlying file descriptor for use with
select() or poll(). Errors are retrieved via icmp_strerror().
Send
int icmp_send_echo(icmp_handle_t *h, struct in_addr dest, uint16_t id,
uint16_t seq, uint8_t ttl,
const void *payload, size_t payload_len);
int icmp_send_raw(icmp_handle_t *h, uint8_t type, uint8_t code,
uint32_t header_rest,
const void *payload, size_t len, struct in_addr dest,
uint8_t ttl);
icmp_send_echo() builds and sends an ICMP ECHO_REQUEST with the given
id, seq, and payload. icmp_send_raw() sends an arbitrary ICMP packet
by type and code.
Receive
typedef void (*icmp_callback_t)(const icmp_reply_t *reply, void *userdata);
int icmp_process(icmp_handle_t *h, icmp_callback_t cb, void *userdata,
size_t max_packets);
icmp_process() drains up to max_packets from the socket in a
non-blocking loop, invoking cb for each one. The icmp_reply_t passed
to the callback contains the ICMP type/code, source address, TTL,
timestamp, and payload. Returns the number of packets processed, or -1
on error.
Modules
handle/
Handle lifecycle: icmp_create(), icmp_destroy(), icmp_get_fd().
Owns the opaque icmp_handle_t struct and the error state attached to it.
socket/
Raw socket creation, non-blocking configuration, and the DF (Don't
Fragment) flag via IP_MTU_DISCOVER.
send/
Packet building and transmission. Assembles the ICMP header and payload, computes the checksum, and writes to the socket.
recv/
Non-blocking receive loop. Reads datagrams, timestamps each one on arrival, and dispatches them through the caller-supplied callback.
packet/
ICMP and IP packet parsing and building. Extracts fields from raw
datagrams, including nested packets inside ICMP error messages
(icmp_offending_packet_t).
error/
Error state storage and formatting. Wraps errno and library-specific
error codes into a single slot on the handle, exposed via
icmp_strerror() and icmp_should_retry().
utils/
RFC 1071 one's-complement checksum and nanosecond time helpers
(icmp_get_time(), icmp_time_diff_ns()).
License
This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.
Authors
- lohhiiccc - Git