forked from stupaq/mcast-radio
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nadajnik.c
266 lines (222 loc) · 7.13 KB
/
nadajnik.c
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#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <event2/event.h>
#include "err.h"
#include "common.h"
#include "proto.h"
#include "sendbuff.h"
#define MAX_PENDING_RET 1<<16
/* transmitter configuration */
static char mcast_dotted[ADDR_LEN] = "";
static in_port_t data_port = DATA_PORT;
static in_port_t ctrl_port = CTRL_PORT;
static int psize = PSIZE;
static int fsize = FSIZE;
static int rtime = RTIME;
static char name[NAME_LEN] = "Nienazwany Nadajnik";
static struct proto_ident pack_my_ident;
static struct proto_packet pack_ret_failed;
/* sockets */
static struct sockaddr_in mcast_addr;
static int mcast_sock;
static int ctrl_sock;
/* events */
static struct event_base *base;
static struct event *stdin_evt;
static struct event *ctrl_evt;
static struct event *rtime_evt;
/* transmitter state */
static seqno_t last_seqno = 0;
/* retransmit requests */
/* if packet in buffer needs to be retransmitted its PROTO_DORETR flag is set */
/* buffered packets */
static struct sendbuff packets;
/* callbacks */
void stdin_cb(evutil_socket_t sock, short ev, void *arg) {
UNUSED(ev);
UNUSED(arg);
static ssize_t len = 0, r = 0;
struct proto_packet *packet = sendbuff_back(&packets);
struct proto_header *header = &packet->header;
TRY_SYS(r = read(sock, packet->data + len, psize - len));
if (r) {
len += r;
if (len == psize) {
/* packet is full, init */
header_init(header, last_seqno++, len, PROTO_DATA);
ASSERT(psize + (int) sizeof(struct proto_header) == packets.hpsize);
ASSERT(packets.hpsize == (int) packet_length(packet));
/* send */
EXPECT(write(mcast_sock, packet, packets.hpsize) == packets.hpsize,
"Sending streming data failed.");
/* start new packet */
len = 0;
sendbuff_next(&packets);
}
} else {
if (len) {
/* end of input, init packet as is */
header_init(header, last_seqno++, len, PROTO_DATA);
/* send */
ASSERT(len + sizeof(struct proto_header));
len = packet_length(packet);
EXPECT(write(mcast_sock, packet, len) == len,
"Sending streaming data failed.");
/* everything sent */
len = 0;
}
/* end of input file, exit */
event_base_loopexit(base, NULL);
}
}
void ctrl_cb(evutil_socket_t sock, short ev, void *arg) {
UNUSED(ev);
UNUSED(arg);
struct proto_header header;
ssize_t r;
struct sockaddr_in addr;
socklen_t addr_len = sizeof(addr);
TRY_SYS(r = recvfrom(sock, &header, sizeof(header), 0,
(struct sockaddr *) &addr, &addr_len));
if (validate_packet((struct proto_packet *) &header, r) && header_isempty(&header)) {
if (header_flag_isset(&header, PROTO_RETQUERY)) {
/* mark packet in buffer with PROTO_DORETR flag */
seqno_t ask_seqno = header_seqno(&header);
struct proto_packet *pack = sendbuff_getseqno(&packets, ask_seqno);
if (pack) {
header_flag_set(&pack->header, PROTO_DORETR);
} else {
/* invalid retransmission request - response directly to requester */
header_init(&pack_ret_failed.header, ask_seqno, 0, PROTO_FAIL);
EXPECT(sendto(ctrl_sock, &pack_ret_failed, sizeof(pack_ret_failed), 0,
(struct sockaddr *) &addr, addr_len) == sizeof(pack_ret_failed),
"Sending invalid retransmission response failed.");
}
}
/* whatever we've done addr is still valid */
if (header_flag_isset(&header, PROTO_IDQUERY)) {
EXPECT(sendto(sock, &pack_my_ident, sizeof(pack_my_ident), 0, (struct sockaddr *)
&addr, addr_len) == sizeof(pack_my_ident),
"Sending id response failed.");
}
}
/* else: ignore packet */
}
void do_retr_cb(evutil_socket_t sock, short ev, void *arg) {
UNUSED(sock);
UNUSED(ev);
UNUSED(arg);
int i = 0;
struct proto_packet *packet;
while ((packet = sendbuff_getnth(&packets, i)) != NULL) {
if (header_flag_isset(&packet->header, PROTO_DORETR)) {
header_flag_clear(&packet->header, PROTO_DORETR);
EXPECT(write(mcast_sock, packet, packets.hpsize) == packets.hpsize,
"Sending retransmission response failed.");
}
/* next */
++i;
}
}
int main(int argc, char **argv) {
/* parse options */
int errflg = 0;
extern char *optarg;
extern int optind, optopt;
int c;
while ((c = getopt(argc, argv, "a:P:C:p:f:R:n:")) != -1) {
switch(c) {
case 'a':
strncpy(mcast_dotted, optarg, sizeof(mcast_dotted) - 1);
if (strlen(mcast_dotted) == 0)
errflg++;
break;
case 'P':
data_port = (in_port_t) atoi(optarg);
break;
case 'C':
ctrl_port = (in_port_t) atoi(optarg);
break;
case 'p':
psize = atoi(optarg);
if (psize <= 0 || psize > (int) PROTO_MAX_DATA)
errflg++;
break;
case 'f':
fsize = atoi(optarg);
if (fsize <= 0)
errflg++;
break;
case 'R':
rtime = atoi(optarg);
if (rtime <= 0)
errflg++;
break;
case 'n':
strncpy(name, optarg, sizeof(name) - 1);
break;
default:
errflg++;
break;
}
}
if (strlen(mcast_dotted) == 0)
errflg++;
if (errflg) {
fprintf(stderr, "Error parsing parameters.\n");
exit(EXIT_FAILURE);
}
/* initialize packets buffer */
sendbuff_init(&packets, fsize, psize);
{
struct sockaddr_in temp_addr;
temp_addr.sin_family = AF_INET;
temp_addr.sin_addr.s_addr = htonl(INADDR_ANY);
/* setup ctrl socket */
temp_addr.sin_port = htons(ctrl_port);
TRY_SYS(ctrl_sock = socket(PF_INET, SOCK_DGRAM, 0));
TRY_SYS(bind(ctrl_sock, (const struct sockaddr *) &temp_addr, sizeof(temp_addr)));
setup_multicast_sockopt(ctrl_sock, MCAST_TTL, MCAST_LOOPBACK);
/* setup mcast socket */
temp_addr.sin_port = htons(0);
TRY_TRUE(sockaddr_dotted(&mcast_addr, mcast_dotted, data_port));
TRY_SYS(mcast_sock = socket(PF_INET, SOCK_DGRAM, 0));
TRY_SYS(bind(mcast_sock, (const struct sockaddr *) &temp_addr, sizeof(temp_addr)));
setup_multicast_sockopt(mcast_sock, MCAST_TTL, MCAST_LOOPBACK);
TRY_SYS(connect(mcast_sock, (struct sockaddr *) &mcast_addr, sizeof(mcast_addr)));
/* better to keep such things precomputed due to no-copy policy */
socklen_t addr_len = sizeof(temp_addr);
TRY_SYS(getsockname(mcast_sock, (struct sockaddr *) &temp_addr, &addr_len));
ident_init(&pack_my_ident, &mcast_addr, &temp_addr, psize);
strncpy(pack_my_ident.tune_name, name, sizeof(pack_my_ident.tune_name) - 1);
strncpy(pack_my_ident.app_name, argv[0], sizeof(pack_my_ident.app_name) - 1);
}
/* NOTE: pack_ret_failed must be reinitialized before sending with proper seqno */
/* setup eventbase */
TRY_TRUE(base = event_base_new());
/* setup events */
TRY_TRUE(stdin_evt = event_new(base, 0, EV_READ|EV_PERSIST, stdin_cb, NULL));
TRY_SYS(event_add(stdin_evt, NULL));
TRY_TRUE(ctrl_evt = event_new(base, ctrl_sock, EV_READ|EV_PERSIST, ctrl_cb, NULL));
TRY_SYS(event_add(ctrl_evt, NULL));
TRY_TRUE(rtime_evt = event_new(base, -1, EV_TIMEOUT|EV_PERSIST, do_retr_cb, NULL));
struct timeval rtime_tv = {(rtime / 1000), 1000*(rtime % 1000)};
TRY_SYS(event_add(rtime_evt, &rtime_tv));
/* dispatcher loop */
TRY_SYS(event_base_dispatch(base));
/* clean exit */
event_free(stdin_evt);
event_free(ctrl_evt);
event_free(rtime_evt);
event_base_free(base);
close(mcast_sock);
sendbuff_free(&packets);
exit(EXIT_SUCCESS);
}