telnetproxy/connection.c

233 lines
5.1 KiB
C
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#include <stdio.h>
#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <time.h>
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#include <netinet/ip.h>
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#include "connection.h"
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#include "event.h"
#include "list.h"
#include "logging.h"
#include "network.h"
struct connection {
struct list_head list;
struct sockaddr_in src_addr;
struct sockaddr_in dst_addr;
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struct event_fd *src_event;
struct event_fd *dst_event;
struct event_timeout *timeout;
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time_t login_time;
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};
static LIST_HEAD(connection_list);
static struct connection * create_connection()
{
struct connection *con = malloc(sizeof(struct connection));
if (con == NULL) {
log_print(LOG_WARN, "listen_handler(): out of memory");
return 0;
}
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memset(con, 0, sizeof(struct connection));
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con->login_time = time(NULL);
return con;
}
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static void destroy_connection(struct connection *con)
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{
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if (con->timeout != NULL)
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event_remove_timeout(con->timeout);
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int src_fd = event_get_fd(con->src_event);
if (src_fd != -1) {
close(src_fd);
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event_remove_fd(con->src_event);
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}
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int dst_fd = event_get_fd(con->dst_event);
if (dst_fd != -1) {
close(dst_fd);
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event_remove_fd(con->dst_event);
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}
free(con);
}
static int forward_handler(int fd, void *privdata)
{
struct connection *con = (struct connection *)privdata;
char buf[256];
int len = read(fd, buf, sizeof(buf));
if (len <= 0) {
list_del(&con->list);
destroy_connection(con);
return -1;
}
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int src_fd = event_get_fd(con->src_event);
int dst_fd = event_get_fd(con->dst_event);
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/* client -> device */
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if (src_fd == fd && dst_fd != -1)
write(dst_fd, buf, len);
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/* device -> client */
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if (dst_fd == fd && src_fd != -1)
write(src_fd, buf, len);
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return 0;
}
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static int connect_handler(int fd, void *privdata)
{
struct connection *con = (struct connection *)privdata;
if (tcp_connect_error(fd)) {
list_del(&con->list);
destroy_connection(con);
return -1;
}
log_print(LOG_INFO, "forwarding to %s", get_sockaddr_buf(&con->dst_addr));
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/* everything from dst will be forwarded */
event_add_readfd(con->dst_event, 0, forward_handler, con);
/* remove connect_handler */
event_add_writefd(con->dst_event, 0, NULL, NULL);
/* remove timeout */
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event_remove_timeout(con->timeout);
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con->timeout = NULL;
return 0;
}
static int connect_timeout(void *privdata)
{
struct connection *con = (struct connection *)privdata;
log_print(LOG_INFO, "connect to %s timed out", get_sockaddr_buf(&con->dst_addr));
list_del(&con->list);
destroy_connection(con);
/* singleshot timer */
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return -1;
}
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static int client_handler(int fd, void *privdata)
{
struct connection *con = (struct connection *)privdata;
char buf[256];
int len = read(fd, buf, sizeof(buf));
if (len <= 0) {
list_del(&con->list);
destroy_connection(con);
return -1;
}
if (parse_saddr(buf, &con->dst_addr) != 0) {
list_del(&con->list);
destroy_connection(con);
return -1;
}
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// TODO: check destination
int dst_fd = tcp_connect_socket(&con->dst_addr);
if (dst_fd < 0) {
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list_del(&con->list);
destroy_connection(con);
return -1;
}
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log_print(LOG_INFO, "connecting to %s", get_sockaddr_buf(&con->dst_addr));
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struct timeval tv;
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tv.tv_sec = 2;
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tv.tv_usec = 0;
con->timeout = event_add_timeout(&tv, connect_timeout, con);
/* wait for connect() (non-blocking) */
con->dst_event = event_add_writefd(NULL, dst_fd, connect_handler, con);
/* everything from src will be forwarded */
event_add_readfd(con->src_event, 0, forward_handler, con);
return 0;
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}
static int admin_handler(int fd, void *privdata)
{
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struct connection *con = (struct connection *)privdata;
char buf[256];
int len = read(fd, buf, sizeof(buf));
if (len <= 0) {
list_del(&con->list);
destroy_connection(con);
return -1;
}
if (strncmp(buf, "list", 4) == 0) {
struct connection *entry;
list_for_each_entry(entry, &connection_list, list) {
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len = snprintf(buf, sizeof(buf), "%d,", event_get_fd(entry->src_event));
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len += get_sockaddr(&entry->src_addr, buf + len, sizeof(buf) - len);
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len += snprintf(buf + len, sizeof(buf) - len, ",%d,", event_get_fd(entry->dst_event));
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len += get_sockaddr(&entry->dst_addr, buf + len, sizeof(buf) - len);
len += snprintf(buf + len, sizeof(buf) - len, ",%ld\n", (time(NULL) - entry->login_time));
write(fd, buf, len);
}
} else if (strncmp(buf, "kill", 4) == 0) {
} else if (strncmp(buf, "quit", 4) == 0) {
list_del(&con->list);
destroy_connection(con);
return -1;
}
return 0;
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}
int listen_handler(int fd, void *privdata)
{
int mode = (int)privdata;
struct connection *con = create_connection();
if (con == NULL) {
log_print(LOG_WARN, "listen_handler(): out of memory");
return 0;
}
unsigned int i = sizeof(con->src_addr);
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int src_fd = accept(fd, (struct sockaddr *)&con->src_addr, &i);
if (src_fd < 0) {
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free(con);
return 0;
}
log_print(LOG_INFO, "accepted connection from %s", get_sockaddr_buf(&con->src_addr));
list_add_tail(&con->list, &connection_list);
if (mode == CON_ADMIN)
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con->src_event = event_add_readfd(NULL, src_fd, admin_handler, con);
else if (mode == CON_NORMAL)
con->src_event = event_add_readfd(NULL, src_fd, client_handler, con);
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return 0;
}