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sslh-select: reduce CPU and memory usage in forked processes

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This commit is contained in:
Oleg Oshmyan 2017-09-09 02:04:03 +03:00
parent 2544f20bdf
commit 2a70470f13
1 changed files with 99 additions and 13 deletions
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112
sslh-select.c
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@ -182,6 +182,93 @@ void shovel(struct connection *cnx, int active_fd,
}
}
/* shovels data from one fd to the other and vice-versa
returns after one socket closed
*/
void shovel_single(struct connection *cnx)
{
fd_set fds_r, fds_w;
int res, i;
int max_fd = MAX(cnx->q[0].fd, cnx->q[1].fd) + 1;
FD_ZERO(&fds_r);
FD_ZERO(&fds_w);
while (1) {
for (i = 0; i < 2; i++) {
if (cnx->q[i].deferred_data_size) {
FD_SET(cnx->q[i].fd, &fds_w);
FD_CLR(cnx->q[1-i].fd, &fds_r);
} else {
FD_CLR(cnx->q[i].fd, &fds_w);
FD_SET(cnx->q[1-i].fd, &fds_r);
}
}
res = select(
max_fd,
&fds_r,
&fds_w,
NULL,
NULL
);
CHECK_RES_DIE(res, "select");
for (i = 0; i < 2; i++) {
if (FD_ISSET(cnx->q[i].fd, &fds_w)) {
res = flush_deferred(&cnx->q[i]);
if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
if (verbose)
fprintf(stderr, "%s socket closed\n", i ? "server" : "client");
return;
}
}
if (FD_ISSET(cnx->q[i].fd, &fds_r)) {
res = fd2fd(&cnx->q[1-i], &cnx->q[i]);
if (!res) {
if (verbose)
fprintf(stderr, "socket closed\n");
return;
}
}
}
}
}
/* Child process that makes internal connection and proxies
*/
void connect_proxy(struct connection *cnx)
{
int in_socket;
int out_socket;
/* Minimize the file descriptor value to help select() */
in_socket = dup(cnx->q[0].fd);
if (in_socket == -1) {
in_socket = cnx->q[0].fd;
} else {
close(cnx->q[0].fd);
cnx->q[0].fd = in_socket;
}
/* Connect the target socket */
out_socket = connect_addr(cnx, in_socket);
CHECK_RES_DIE(out_socket, "connect");
cnx->q[1].fd = out_socket;
log_connection(cnx);
shovel_single(cnx);
close(in_socket);
close(out_socket);
if (verbose)
fprintf(stderr, "connection closed down\n");
exit(0);
}
/* returns true if specified fd is initialised and present in fd_set */
int is_fd_active(int fd, fd_set* set)
{
@ -323,22 +410,21 @@ void main_loop(int listen_sockets[], int num_addr_listen)
res = -1;
} else if (cnx[i].proto->fork) {
if (!fork()) {
struct connection *cnx_i = &cnx[i];
for (i = 0; i < num_addr_listen; i++) {
FD_CLR(listen_sockets[i], &fds_r);
struct connection *pcnx_i = &cnx[i];
struct connection cnx_i = *pcnx_i;
for (i = 0; i < num_addr_listen; i++)
close(listen_sockets[i]);
}
num_addr_listen = 0;
for (i = 0; i < num_cnx; i++)
if (&cnx[i] != cnx_i)
tidy_connection(&cnx[i], &fds_r, &fds_w);
num_probing = 0;
res = connect_queue(cnx_i, &fds_r, &fds_w);
max_fd = MAX(cnx_i->q[0].fd, cnx_i->q[1].fd) + 1;
} else {
tidy_connection(&cnx[i], &fds_r, &fds_w);
res = -1;
if (&cnx[i] != pcnx_i)
for (j = 0; j < 2; j++)
if (cnx[i].q[j].fd != -1)
close(cnx[i].q[j].fd);
free(cnx);
connect_proxy(&cnx_i);
exit(0);
}
tidy_connection(&cnx[i], &fds_r, &fds_w);
res = -1;
} else {
res = connect_queue(&cnx[i], &fds_r, &fds_w);
}