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/* Implementation for netns_socket API
*
* This file is part of rsyslog.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
* -or-
* see COPYING.ASL20 in the source distribution
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "config.h"
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include "rsyslog.h"
#include "debug.h"
#include "errmsg.h"
#include "netns_socket.h"
/* Change to the given network namespace.
* This function based on previous implementation
* of tools/omfwd.c function changeToNs.
*/
rsRetVal netns_switch(const char *ns) {
DEFiRet;
#ifdef HAVE_SETNS
int ns_fd = -1;
char *nsPath = NULL;
if (ns && *ns) {
/* Build network namespace path */
if (asprintf(&nsPath, "/var/run/netns/%s", ns) == -1) {
// Some implementations say nsPath would be undefined on failure
nsPath = NULL;
LogError(0, RS_RET_OUT_OF_MEMORY, "%s: asprintf failed", __func__);
ABORT_FINALIZE(RS_RET_OUT_OF_MEMORY);
}
/* Open file descriptor of destination network namespace */
ns_fd = open(nsPath, O_RDONLY);
if (ns_fd < 0) {
LogError(errno, RS_RET_IO_ERROR, "%s: could not open namespace '%s'", __func__, ns);
ABORT_FINALIZE(RS_RET_IO_ERROR);
}
/* Change to the destination network namespace */
if (setns(ns_fd, CLONE_NEWNET) != 0) {
LogError(errno, RS_RET_IO_ERROR, "%s: could not change to namespace '%s'", __func__, ns);
ABORT_FINALIZE(RS_RET_IO_ERROR);
}
dbgprintf("%s: changed to network namespace '%s'\n", __func__, ns);
}
finalize_it:
free(nsPath);
if ((ns_fd >= 0) && (close(ns_fd) != 0)) {
LogError(errno, RS_RET_IO_ERROR, "%s: failed to close namespace '%s'", __func__, ns);
}
#else // ndef HAVE_SETNS
if (ns && *ns) {
LogError(ENOSYS, RS_RET_VALUE_NOT_SUPPORTED, "%s: could not change to namespace '%s'", __func__, ns);
ABORT_FINALIZE(RS_RET_VALUE_NOT_SUPPORTED);
}
finalize_it:
#endif // ndef HAVE_SETNS
RETiRet;
}
/* Return to the startup network namespace.
* This function based on code in tools/omfwd.c
*/
rsRetVal ATTR_NONNULL() netns_restore(int *fd) {
DEFiRet;
#ifdef HAVE_SETNS
if (*fd >= 0) {
if (setns(*fd, CLONE_NEWNET) != 0) {
LogError(errno, RS_RET_IO_ERROR, "%s: could not return to startup namespace", __func__);
ABORT_FINALIZE(RS_RET_IO_ERROR);
}
dbgprintf("%s: returned to startup network namespace\n", __func__);
}
finalize_it:
#endif // def HAVE_SETNS
if (*fd >= 0 && close(*fd) != 0) {
LogError(errno, RS_RET_IO_ERROR, "%s: could not close startup namespace fd", __func__);
}
*fd = -1;
RETiRet;
}
/* Save the current network namespace fd
*/
rsRetVal ATTR_NONNULL() netns_save(int *fd) {
DEFiRet;
/*
* The fd must always point to either a valid fd
* or to -1. We expect it to be -1 on entry here.
* To avoid bugs, or possible descriptor leaks,
* check that it is always -1 on entry.
*/
#ifdef HAVE_SETNS
if (*fd != -1) {
LogError(0, RS_RET_CODE_ERR, "%s: called with uninitialized descriptor", __func__);
ABORT_FINALIZE(RS_RET_CODE_ERR);
}
*fd = open("/proc/self/ns/net", O_RDONLY);
if (*fd == -1) {
LogError(errno, RS_RET_IO_ERROR, "%s: could not access startup namespace", __func__);
ABORT_FINALIZE(RS_RET_IO_ERROR);
}
dbgprintf("%s: saved startup network namespace\n", __func__);
finalize_it:
#endif // def HAVE_SETNS
RETiRet;
}
rsRetVal netns_socket(int *fdp, int domain, int type, int protocol, const char *ns) {
DEFiRet;
int fd = -1;
#ifndef HAVE_SETNS
if (ns && *ns) {
LogError(0, RS_RET_VALUE_NOT_SUPPORTED, "Network namespaces are not supported");
ABORT_FINALIZE(RS_RET_VALUE_NOT_SUPPORTED);
}
#else /* def HAVE_SETNS */
rsRetVal iRet_restore;
int ns_fd = -1;
if (ns && *ns) {
CHKiRet(netns_save(&ns_fd));
CHKiRet(netns_switch(ns));
}
#endif /* def HAVE_SETNS */
*fdp = fd = socket(domain, type, protocol);
if (fd == -1) {
LogError(errno, RS_RET_NO_SOCKET, "%s: socket(%d, %d, %d) failed", __func__, domain, type, protocol);
ABORT_FINALIZE(RS_RET_NO_SOCKET);
}
finalize_it:
#ifdef HAVE_SETNS
iRet_restore = netns_restore(&ns_fd);
if (iRet == RS_RET_OK) iRet = iRet_restore;
#endif /* def HAVE_SETNS */
if (iRet != RS_RET_OK && fd != -1) {
(void)close(fd);
*fdp = -1;
}
RETiRet;
}
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