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/* SPDX-License-Identifier: Unlicense */
#include "proto.h"
#include "proto_io.h"
#include "timespec/timespec.h"
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <netinet/in.h>
#include <poll.h>
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <time.h>
#include <unistd.h>
struct connection {
int fd;
uint16_t port;
uint32_t addr;
bool connected;
uint32_t connection_id;
struct timespec last_syn;
uint32_t server_roundtrip_prev;
uint32_t client_roundtrip_prev;
};
static volatile bool g_should_exit = false;
struct connection g_conn = { .fd = -1, };
static inline bool IsDigit(char c) { return c >= '0' && c <= '9'; }
static void HandleFrame(
struct connection *self,
struct frame const *frame,
struct timespec now)
{
if (frame->type == FT_HANDSHAKE_RESP) {
self->connection_id = frame->connection_id;
self->connected = true;
} else if (frame->type == FT_SYN && self->connected) {
printf("client_rt %5" PRIu32 "\n", self->client_roundtrip_prev);
struct frame outgoing = *frame;
outgoing.type = FT_SYNACK,
outgoing.syn = (struct frame_data_syn){
.tick = frame->syn.tick,
.roundtrip_prev = self->client_roundtrip_prev,
.prev_is_lost = false,
};
SendFrame(self->fd, &outgoing);
self->last_syn = now;
self->server_roundtrip_prev = frame->syn.roundtrip_prev;
} else if (frame->type == FT_ACK && self->connected) {
long const ms = timespec_to_ms(timespec_sub(now, self->last_syn));
assert(ms >= 0);
self->client_roundtrip_prev = ms;
} else if (frame->type == FT_RST) {
// TODO
}
}
static uint32_t ParseAddress(char const *str, FILE *log_stream)
{
uint32_t addr = 0;
unsigned byte_counter = 0, byte = 0, digits_counter = 0;
for (size_t i = 0;; i++) {
char const c = str[i];
if (c == '\0') {
if (byte_counter != 3) {
fprintf(log_stream, "Invalid address specified: %u bytes of 4 expected are specified\n", byte_counter + 1);
return INADDR_NONE;
}
if (digits_counter == 0) {
fprintf(log_stream, "Invalid address specified: no digits on byte %u\n", byte_counter + 1);
return INADDR_NONE;
}
addr |= byte << (8 * (3 - byte_counter));
break;
} else if (IsDigit(c)) {
digits_counter++;
if (digits_counter > 3) {
fprintf(log_stream, "Invalid address specified: too many digits for byte %u\n", byte_counter + 1);
return INADDR_NONE;
}
byte = byte * 10 + (c - '0');
if (byte > UINT8_MAX) {
fprintf(log_stream, "Invalid address specified: too big number for byte %u\n", byte_counter + 1);
return INADDR_NONE;
}
} else if (c == '.') {
if (digits_counter == 0) {
fprintf(log_stream, "Invalid address specified: no digits on byte %u\n", byte_counter + 1);
return INADDR_NONE;
}
digits_counter = 0;
addr |= byte << (8 * (3 - byte_counter));
byte = 0;
byte_counter++;
if (byte_counter > 3) {
fprintf(log_stream, "Invalid address specified: unexpected dot after 4th byte\n");
return INADDR_NONE;
}
} else {
fprintf(log_stream, "Invalid address specified: char '%c' (0x%02x) is not allowed\n", c, c);
return INADDR_NONE;
}
}
if (addr == INADDR_NONE) {
fprintf(log_stream, "Invalid address specified\n");
}
return addr;
}
static void sigintHandler(int a)
{
(void) a;
}
int main(int const argc, char *const argv[])
{
if (argc < 3) {
fprintf(stderr, "Usage: %s <address> <port>\n", argv[0]);
return 1;
}
unsigned const addr = ParseAddress(argv[1], stderr);
if (addr == INADDR_NONE) {
return 1;
}
int const port = atoi(argv[2]);
if (port <= 0 || port > UINT16_MAX) {
fprintf(stderr, "Invalid port specified\n");
return 1;
}
int const fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
perror("socket failed");
return 1;
}
fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);
g_conn.addr = addr;
g_conn.port = port;
g_conn.fd = fd;
struct frame const handshake = {
.addr = addr,
.port = port,
.type = FT_HANDSHAKE,
.handshake = {
.tick_period = 200,
},
};
SendFrame(fd, &handshake);
struct sigaction sa = { .sa_handler = sigintHandler, };
sigaction(SIGINT, &sa, NULL);
struct pollfd fds[1] = { { .fd = fd, .events = POLLIN, }, };
while (!g_should_exit) {
int const pollret = poll(fds, sizeof(fds)/sizeof(*fds), -1);
int const poll_err = errno;
struct timespec start;
if (-1 == clock_gettime(CLOCK_MONOTONIC, &start)) {
int const err = errno;
fprintf(stderr,
"clock_gettime(CLOCK_MONOTONIC, &start) failed (%d): \"%s\"",
err, strerror(err));
}
if (pollret > 0) {
if (fds[0].revents & POLLIN) {
while (1) {
struct frame frame = { .type = FT_NONE, };
int const ret = ReceiveFrame(fds[0].fd, &frame);
if (ret) {
break;
}
HandleFrame(&g_conn, &frame, start);
}
}
if (fds[0].revents & POLLRDNORM) {
fprintf(stderr, "POLLRDNORM, ignoring...\n");
}
if (fds[0].revents & POLLRDBAND) {
fprintf(stderr, "POLLRDBAND, ignoring...\n");
}
if (fds[0].revents & POLLPRI) {
fprintf(stderr, "POLLPRI, ignoring...\n");
}
if (fds[0].revents & POLLPRI) {
fprintf(stderr, "POLLPRI, ignoring...\n");
}
if (fds[0].revents & POLLHUP) {
fprintf(stderr, "POLLHUP, ignoring...\n");
}
if (fds[0].revents & POLLERR) {
fprintf(stderr, "POLLERR, ignoring...\n");
}
if (fds[0].revents & POLLNVAL) {
fprintf(stderr, "POLLNVAL, exiting...\n");
return 1;
}
} else if (pollret < 0) {
if (poll_err == EINTR) {
fprintf(stderr, "SIGINT received\n");
if (g_conn.connected) {
struct frame const rst = {
.addr = g_conn.addr,
.port = g_conn.port,
.type = FT_RST,
};
SendFrame(g_conn.fd, &rst);
}
break;
}
fprintf(stderr,
"poll() failed (%d): \"%s\"",
poll_err, strerror(poll_err));
}
}
close(fd);
}
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