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#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
int fullread(int fd, void *_buf, int count)
{
char *buf = _buf;
int ret = 0;
int l;
while (count) {
l = read(fd, buf, count);
if (l <= 0) return -1;
count -= l;
buf += l;
ret += l;
}
return ret;
}
int fullwrite(int fd, void *_buf, int count)
{
char *buf = _buf;
int ret = 0;
int l;
while (count) {
l = write(fd, buf, count);
if (l <= 0) return -1;
count -= l;
buf += l;
ret += l;
}
return ret;
}
#include "common_lib.h"
typedef struct {
int sock;
int samples_per_subframe;
uint64_t timestamp;
uint64_t next_tx_timestamp;
int is_enb;
} tcp_bridge_state_t;
void verify_connection(int fd, int is_enb)
{
char c = is_enb;
if (fullwrite(fd, &c, 1) != 1) exit(1);
if (fullread(fd, &c, 1) != 1) exit(1);
if (c == is_enb) {
printf("\x1b[31mtcp_bridge: error: you have to run one UE and one eNB"
" (did you run 'export ENODEB=1' in the eNB terminal?)\x1b[m\n");
exit(1);
}
}
int tcp_bridge_start(openair0_device *device)
{
int port = 4043;
tcp_bridge_state_t *tcp_bridge = device->priv;
int try;
int max_try = 5;
int sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock == -1) { perror("tcp_bridge: socket"); exit(1); }
int enable = 1;
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)))
{ perror("tcp_bridge: SO_REUSEADDR"); exit(1); }
struct sockaddr_in addr = {
sin_family: AF_INET,
sin_port: htons(port),
sin_addr: { s_addr: INADDR_ANY }
};
if (bind(sock, (struct sockaddr *)&addr, sizeof(addr))) {
if (errno == EADDRINUSE) goto client_mode;
{ perror("tcp_bridge: bind"); exit(1); }
}
if (listen(sock, 5))
{ perror("tcp_bridge: listen"); exit(1); }
printf("tcp_bridge: wait for connection on port %d\n", port);
socklen_t len = sizeof(addr);
int sock2 = accept(sock, (struct sockaddr *)&addr, &len);
if (sock2 == -1)
{ perror("tcp_bridge: accept"); exit(1); }
close(sock);
tcp_bridge->sock = sock2;
printf("tcp_bridge: connection established\n");
verify_connection(sock2, tcp_bridge->is_enb);
return 0;
client_mode:
addr.sin_addr.s_addr = inet_addr("127.0.0.1");
for (try = 0; try < max_try; try++) {
if (try != 0) sleep(1);
printf("tcp_bridge: trying to connect to 127.0.0.1:%d (attempt %d/%d)\n",
port, try+1, max_try);
if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) {
printf("tcp_bridge: connection established\n");
tcp_bridge->sock = sock;
verify_connection(sock, tcp_bridge->is_enb);
return 0;
}
perror("tcp_bridge");
}
printf("tcp_bridge: connection failed\n");
exit(1);
}
int tcp_bridge_request(openair0_device *device, void *msg, ssize_t msg_len) { abort(); return 0; }
int tcp_bridge_reply(openair0_device *device, void *msg, ssize_t msg_len) { abort(); return 0; }
int tcp_bridge_get_stats(openair0_device* device) { return 0; }
int tcp_bridge_reset_stats(openair0_device* device) { return 0; }
void tcp_bridge_end(openair0_device *device) {}
int tcp_bridge_stop(openair0_device *device) { return 0; }
int tcp_bridge_set_freq(openair0_device* device, openair0_config_t *openair0_cfg,int exmimo_dump_config) { return 0; }
int tcp_bridge_set_gains(openair0_device* device, openair0_config_t *openair0_cfg) { return 0; }
int tcp_bridge_write(openair0_device *device, openair0_timestamp timestamp, void **buff, int nsamps, int cc, int flags)
{
if (cc != 1) { printf("tcp_bridge: only 1 antenna supported\n"); exit(1); }
tcp_bridge_state_t *t = device->priv;
/* deal with discontinuities in output (think: eNB in TDD mode) */
if (t->next_tx_timestamp && timestamp != t->next_tx_timestamp) {
uint32_t b[4096];
uint64_t to_send = timestamp - t->next_tx_timestamp;
memset(b, 0, 4096 * sizeof(uint32_t));
while (to_send) {
int len = to_send > 4096 ? 4096 : to_send;
int n = fullwrite(t->sock, b, len * 4);
if (n != len * 4) {
printf("tcp_bridge: write error ret %d error %s\n", n, strerror(errno));
abort();
}
to_send -= len;
}
}
int n = fullwrite(t->sock, buff[0], nsamps * 4);
if (n != nsamps * 4) {
printf("tcp_bridge: write error ret %d (wanted %d) error %s\n", n, nsamps*4, strerror(errno));
abort();
}
t->next_tx_timestamp = timestamp + nsamps;
return nsamps;
}
int tcp_bridge_read(openair0_device *device, openair0_timestamp *timestamp, void **buff, int nsamps, int cc)
{
if (cc != 1) { printf("tcp_bridge: only 1 antenna supported\n"); exit(1); }
tcp_bridge_state_t *t = device->priv;
int n = fullread(t->sock, buff[0], nsamps * 4);
if (n != nsamps * 4) {
printf("tcp_bridge: read error ret %d nsamps*4 %d error %s\n", n, nsamps * 4, strerror(errno));
abort();
}
*timestamp = t->timestamp;
t->timestamp += nsamps;
return nsamps;
}
int tcp_bridge_read_ue(openair0_device *device, openair0_timestamp *timestamp, void **buff, int nsamps, int cc)
{
if (cc != 1) { printf("tcp_bridge: only 1 antenna supported\n"); exit(1); }
tcp_bridge_state_t *t = device->priv;
int n;
/* In synch mode, UE does not write, but we need to
* send something to the eNodeB.
* We know that UE is in synch mode when it reads
* 10 subframes at a time.
*/
if (nsamps == t->samples_per_subframe * 10) {
uint32_t b[nsamps];
memset(b, 0, nsamps * 4);
n = fullwrite(t->sock, b, nsamps * 4);
if (n != nsamps * 4) {
printf("tcp_bridge: write error ret %d error %s\n", n, strerror(errno));
abort();
}
}
return tcp_bridge_read(device, timestamp, buff, nsamps, cc);
}
/* To startup proper communcation between eNB and UE,
* we need to understand that:
* - eNodeB starts reading subframe 0
* - then eNodeB starts sending subframe 4
* and then repeats read/write for each subframe.
* The UE:
* - reads 10 subframes at a time until it is synchronized
* - then reads subframe n and writes subframe n+2
* We also want to enforce that the subframe 0 is read
* at the beginning of the UE RX buffer, not in the middle
* of it.
* So it means:
* - for the eNodeB: let it run as in normal mode (as with a B210)
* - for the UE, on its very first read:
* - we want this read to get data from subframe 0
* but the first write of eNodeB is subframe 4
* so we first need to read and ignore 6 subframes
* - the UE will start its TX only at the subframe 2
* corresponding to the subframe 0 it just read,
* so we need to write 12 subframes before anything
* (the function tcp_bridge_read_ue takes care to
* insert dummy TX data during the synch phase)
*
* Here is a drawing of the beginning of things to make
* this logic clearer.
*
* We see that eNB starts RX at subframe 0, starts TX at subfram 4,
* and that UE starts RX at subframe 10 and TX at subframe 12.
*
* We understand that the UE has to transmit 12 empty
* subframes for the eNodeB to start its processing.
*
* And because the eNodeB starts its TX at subframe 4 and we
* want the UE to start its RX at subframe 10, we need to
* read and ignore 6 subframes in the UE.
*
* -------------------------------------------------------------------------
* eNB RX: | *0* | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 ...
* -------------------------------------------------------------------------
*
* -------------------------------------------------------------------------
* eNB TX: | 0 | 1 | 2 | 3 | *4* | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 ...
* -------------------------------------------------------------------------
*
* -------------------------------------------------------------------------
* UE RX: | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | *10* | 11 | 12 | 13 | 14 ...
* -------------------------------------------------------------------------
*
* -------------------------------------------------------------------------
* UE TX: | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | *12* | 13 | 14 ...
* -------------------------------------------------------------------------
*
* As a final note, we do TX before RX to ensure that the eNB will
* get some data and send us something so there is no deadlock
* at the beginning of things. Hopefully the kernel buffers for
* the sockets are big enough so that the first (big) TX can
* return to user mode before the buffers are full. If this
* is wrong in some environment, we will need to work by smaller
* units of data at a time.
*/
int tcp_bridge_ue_first_read(openair0_device *device, openair0_timestamp *timestamp, void **buff, int nsamps, int cc)
{
if (cc != 1) { printf("tcp_bridge: only 1 antenna supported\n"); exit(1); }
tcp_bridge_state_t *t = device->priv;
uint32_t b[t->samples_per_subframe * 12];
memset(b, 0, t->samples_per_subframe * 12 * 4);
int n = fullwrite(t->sock, b, t->samples_per_subframe * 12 * 4);
if (n != t->samples_per_subframe * 12 * 4) {
printf("tcp_bridge: write error ret %d error %s\n", n, strerror(errno));
abort();
}
n = fullread(t->sock, b, t->samples_per_subframe * 6 * 4);
if (n != t->samples_per_subframe * 6 * 4) {
printf("tcp_bridge: read error ret %d error %s\n", n, strerror(errno));
abort();
}
device->trx_read_func = tcp_bridge_read_ue;
return tcp_bridge_read_ue(device, timestamp, buff, nsamps, cc);
}
__attribute__((__visibility__("default")))
int device_init(openair0_device* device, openair0_config_t *openair0_cfg)
{
tcp_bridge_state_t *tcp_bridge = (tcp_bridge_state_t*)malloc(sizeof(tcp_bridge_state_t));
memset(tcp_bridge, 0, sizeof(tcp_bridge_state_t));
tcp_bridge->is_enb = getenv("ENODEB") != NULL;
printf("tcp_bridge: running as %s\n", tcp_bridge->is_enb ? "eNB" : "UE");
/* only 25, 50 or 100 PRBs handled for the moment */
if (openair0_cfg[0].sample_rate != 30720000 &&
openair0_cfg[0].sample_rate != 15360000 &&
openair0_cfg[0].sample_rate != 7680000) {
printf("tcp_bridge: ERROR: only 25, 50 or 100 PRBs supported\n");
exit(1);
}
device->trx_start_func = tcp_bridge_start;
device->trx_get_stats_func = tcp_bridge_get_stats;
device->trx_reset_stats_func = tcp_bridge_reset_stats;
device->trx_end_func = tcp_bridge_end;
device->trx_stop_func = tcp_bridge_stop;
device->trx_set_freq_func = tcp_bridge_set_freq;
device->trx_set_gains_func = tcp_bridge_set_gains;
device->trx_write_func = tcp_bridge_write;
if (tcp_bridge->is_enb) {
device->trx_read_func = tcp_bridge_read;
} else {
device->trx_read_func = tcp_bridge_ue_first_read;
}
device->priv = tcp_bridge;
switch ((int)openair0_cfg[0].sample_rate) {
case 30720000: tcp_bridge->samples_per_subframe = 30720; break;
case 15360000: tcp_bridge->samples_per_subframe = 15360; break;
case 7680000: tcp_bridge->samples_per_subframe = 7680; break;
}
/* let's pretend to be a b2x0 */
device->type = USRP_B200_DEV;
device->openair0_cfg=&openair0_cfg[0];
return 0;
}