libhydra: Move all kernel plugins to libcharon
This commit is contained in:
Tobias Brunner
@@ -0,0 +1,655 @@
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/*
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* Copyright (C) 2014 Martin Willi
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* Copyright (C) 2014 revosec AG
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* Copyright (C) 2008 Tobias Brunner
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <sys/socket.h>
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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#include <linux/xfrm.h>
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#include <errno.h>
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#include <unistd.h>
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#include "kernel_netlink_shared.h"
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#include <utils/debug.h>
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#include <threading/mutex.h>
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#include <threading/condvar.h>
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#include <collections/array.h>
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#include <collections/hashtable.h>
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typedef struct private_netlink_socket_t private_netlink_socket_t;
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/**
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* Private variables and functions of netlink_socket_t class.
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*/
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struct private_netlink_socket_t {
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/**
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* public part of the netlink_socket_t object.
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*/
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netlink_socket_t public;
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/**
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* mutex to lock access entries
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*/
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mutex_t *mutex;
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/**
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* Netlink request entries currently active, uintptr_t seq => entry_t
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*/
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hashtable_t *entries;
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/**
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* Current sequence number for Netlink requests
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*/
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refcount_t seq;
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/**
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* netlink socket
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*/
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int socket;
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/**
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* Netlink protocol
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*/
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int protocol;
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/**
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* Enum names for Netlink messages
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*/
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enum_name_t *names;
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/**
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* Timeout for Netlink replies, in ms
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*/
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u_int timeout;
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/**
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* Number of times to repeat timed out queries
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*/
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u_int retries;
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/**
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* Buffer size for received Netlink messages
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*/
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u_int buflen;
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/**
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* Use parallel netlink queries
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*/
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bool parallel;
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/**
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* Ignore errors potentially resulting from a retransmission
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*/
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bool ignore_retransmit_errors;
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};
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/**
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* #definable hook to simulate request message loss
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*/
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#ifdef NETLINK_MSG_LOSS_HOOK
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bool NETLINK_MSG_LOSS_HOOK(struct nlmsghdr *msg);
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#define msg_loss_hook(msg) NETLINK_MSG_LOSS_HOOK(msg)
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#else
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#define msg_loss_hook(msg) FALSE
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#endif
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/**
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* Request entry the answer for a waiting thread is collected in
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*/
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typedef struct {
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/** Condition variable thread is waiting */
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condvar_t *condvar;
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/** Array of hdrs in a multi-message response, as struct nlmsghdr* */
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array_t *hdrs;
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/** All response messages received? */
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bool complete;
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} entry_t;
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/**
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* Clean up a thread waiting entry
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*/
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static void destroy_entry(entry_t *entry)
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{
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entry->condvar->destroy(entry->condvar);
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array_destroy_function(entry->hdrs, (void*)free, NULL);
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free(entry);
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}
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/**
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* Write a Netlink message to socket
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*/
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static bool write_msg(private_netlink_socket_t *this, struct nlmsghdr *msg)
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{
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struct sockaddr_nl addr = {
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.nl_family = AF_NETLINK,
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};
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int len;
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if (msg_loss_hook(msg))
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{
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return TRUE;
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}
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while (TRUE)
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{
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len = sendto(this->socket, msg, msg->nlmsg_len, 0,
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(struct sockaddr*)&addr, sizeof(addr));
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if (len != msg->nlmsg_len)
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{
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if (errno == EINTR)
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{
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continue;
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}
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DBG1(DBG_KNL, "netlink write error: %s", strerror(errno));
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return FALSE;
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}
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return TRUE;
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}
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}
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/**
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* Read a single Netlink message from socket, return 0 on error, -1 on timeout
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*/
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static ssize_t read_msg(private_netlink_socket_t *this,
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char *buf, size_t buflen, bool block)
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{
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ssize_t len;
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if (block)
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{
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fd_set set;
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timeval_t tv = {};
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FD_ZERO(&set);
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FD_SET(this->socket, &set);
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timeval_add_ms(&tv, this->timeout);
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if (select(this->socket + 1, &set, NULL, NULL,
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this->timeout ? &tv : NULL) <= 0)
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{
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return -1;
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}
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}
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len = recv(this->socket, buf, buflen, MSG_TRUNC|(block ? 0 : MSG_DONTWAIT));
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if (len > buflen)
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{
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DBG1(DBG_KNL, "netlink response exceeds buffer size");
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return 0;
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}
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if (len < 0)
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{
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if (errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR)
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{
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DBG1(DBG_KNL, "netlink read error: %s", strerror(errno));
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}
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return 0;
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}
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return len;
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}
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/**
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* Queue received response message
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*/
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static bool queue(private_netlink_socket_t *this, struct nlmsghdr *buf)
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{
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struct nlmsghdr *hdr;
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entry_t *entry;
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uintptr_t seq;
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seq = (uintptr_t)buf->nlmsg_seq;
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this->mutex->lock(this->mutex);
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entry = this->entries->get(this->entries, (void*)seq);
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if (entry)
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{
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hdr = malloc(buf->nlmsg_len);
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memcpy(hdr, buf, buf->nlmsg_len);
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array_insert(entry->hdrs, ARRAY_TAIL, hdr);
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if (hdr->nlmsg_type == NLMSG_DONE || !(hdr->nlmsg_flags & NLM_F_MULTI))
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{
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entry->complete = TRUE;
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entry->condvar->signal(entry->condvar);
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}
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}
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else
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{
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DBG1(DBG_KNL, "received unknown netlink seq %u, ignored", seq);
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}
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this->mutex->unlock(this->mutex);
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return entry != NULL;
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}
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/**
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* Read and queue response message, optionally blocking, returns TRUE on timeout
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*/
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static bool read_and_queue(private_netlink_socket_t *this, bool block)
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{
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struct nlmsghdr *hdr;
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char buf[this->buflen];
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ssize_t len;
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len = read_msg(this, buf, sizeof(buf), block);
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if (len == -1)
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{
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return TRUE;
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}
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if (len)
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{
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hdr = (struct nlmsghdr*)buf;
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while (NLMSG_OK(hdr, len))
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{
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if (!queue(this, hdr))
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{
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break;
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}
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hdr = NLMSG_NEXT(hdr, len);
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}
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}
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return FALSE;
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}
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CALLBACK(watch, bool,
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private_netlink_socket_t *this, int fd, watcher_event_t event)
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{
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if (event == WATCHER_READ)
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{
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read_and_queue(this, FALSE);
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}
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return TRUE;
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}
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/**
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* Send a netlink request, try once
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*/
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static status_t send_once(private_netlink_socket_t *this, struct nlmsghdr *in,
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uintptr_t seq, struct nlmsghdr **out, size_t *out_len)
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{
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struct nlmsghdr *hdr;
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chunk_t result = {};
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entry_t *entry;
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in->nlmsg_seq = seq;
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in->nlmsg_pid = getpid();
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if (this->names)
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{
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DBG3(DBG_KNL, "sending %N %u: %b", this->names, in->nlmsg_type,
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(u_int)seq, in, in->nlmsg_len);
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}
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this->mutex->lock(this->mutex);
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if (!write_msg(this, in))
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{
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this->mutex->unlock(this->mutex);
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return FAILED;
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}
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INIT(entry,
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.condvar = condvar_create(CONDVAR_TYPE_DEFAULT),
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.hdrs = array_create(0, 0),
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);
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this->entries->put(this->entries, (void*)seq, entry);
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while (!entry->complete)
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{
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if (this->parallel &&
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lib->watcher->get_state(lib->watcher) == WATCHER_RUNNING)
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{
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if (this->timeout)
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{
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if (entry->condvar->timed_wait(entry->condvar, this->mutex,
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this->timeout))
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{
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break;
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}
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}
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else
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{
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entry->condvar->wait(entry->condvar, this->mutex);
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}
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}
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else
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{ /* During (de-)initialization, no watcher thread is active.
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* collect responses ourselves. */
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if (read_and_queue(this, TRUE))
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{
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break;
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}
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}
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}
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this->entries->remove(this->entries, (void*)seq);
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this->mutex->unlock(this->mutex);
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if (!entry->complete)
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{ /* timeout */
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destroy_entry(entry);
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return OUT_OF_RES;
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}
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while (array_remove(entry->hdrs, ARRAY_HEAD, &hdr))
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{
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if (this->names)
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{
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DBG3(DBG_KNL, "received %N %u: %b", this->names, hdr->nlmsg_type,
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hdr->nlmsg_seq, hdr, hdr->nlmsg_len);
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}
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result = chunk_cat("mm", result,
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chunk_create((char*)hdr, hdr->nlmsg_len));
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}
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destroy_entry(entry);
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*out_len = result.len;
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*out = (struct nlmsghdr*)result.ptr;
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return SUCCESS;
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}
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/**
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* Ignore errors for message types that might have completed previously
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*/
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static void ignore_retransmit_error(private_netlink_socket_t *this,
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struct nlmsgerr *err, int type)
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{
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switch (err->error)
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{
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case -EEXIST:
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switch (this->protocol)
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{
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case NETLINK_XFRM:
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switch (type)
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{
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case XFRM_MSG_NEWPOLICY:
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case XFRM_MSG_NEWSA:
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err->error = 0;
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break;
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}
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break;
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case NETLINK_ROUTE:
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switch (type)
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{
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case RTM_NEWADDR:
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case RTM_NEWLINK:
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case RTM_NEWNEIGH:
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case RTM_NEWROUTE:
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case RTM_NEWRULE:
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err->error = 0;
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break;
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}
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break;
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}
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break;
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case -ENOENT:
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switch (this->protocol)
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{
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case NETLINK_XFRM:
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switch (type)
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{
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case XFRM_MSG_DELPOLICY:
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case XFRM_MSG_DELSA:
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err->error = 0;
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break;
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}
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break;
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case NETLINK_ROUTE:
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switch (type)
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{
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case RTM_DELADDR:
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case RTM_DELLINK:
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case RTM_DELNEIGH:
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case RTM_DELROUTE:
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case RTM_DELRULE:
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err->error = 0;
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break;
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}
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break;
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}
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break;
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}
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}
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METHOD(netlink_socket_t, netlink_send, status_t,
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private_netlink_socket_t *this, struct nlmsghdr *in, struct nlmsghdr **out,
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size_t *out_len)
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{
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uintptr_t seq;
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u_int try;
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seq = ref_get(&this->seq);
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for (try = 0; try <= this->retries; ++try)
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{
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struct nlmsghdr *hdr;
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status_t status;
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size_t len;
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if (try > 0)
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{
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DBG1(DBG_KNL, "retransmitting Netlink request (%u/%u)",
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try, this->retries);
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}
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status = send_once(this, in, seq, &hdr, &len);
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switch (status)
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{
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case SUCCESS:
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break;
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case OUT_OF_RES:
|
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continue;
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default:
|
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return status;
|
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}
|
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if (hdr->nlmsg_type == NLMSG_ERROR)
|
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{
|
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struct nlmsgerr* err;
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err = NLMSG_DATA(hdr);
|
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if (err->error == -EBUSY)
|
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{
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free(hdr);
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try--;
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continue;
|
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}
|
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if (this->ignore_retransmit_errors && try > 0)
|
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{
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ignore_retransmit_error(this, err, in->nlmsg_type);
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}
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}
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*out = hdr;
|
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*out_len = len;
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return SUCCESS;
|
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}
|
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DBG1(DBG_KNL, "Netlink request timed out after %u retransmits",
|
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this->retries);
|
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return OUT_OF_RES;
|
||||
}
|
||||
|
||||
METHOD(netlink_socket_t, netlink_send_ack, status_t,
|
||||
private_netlink_socket_t *this, struct nlmsghdr *in)
|
||||
{
|
||||
struct nlmsghdr *out, *hdr;
|
||||
size_t len;
|
||||
|
||||
if (netlink_send(this, in, &out, &len) != SUCCESS)
|
||||
{
|
||||
return FAILED;
|
||||
}
|
||||
hdr = out;
|
||||
while (NLMSG_OK(hdr, len))
|
||||
{
|
||||
switch (hdr->nlmsg_type)
|
||||
{
|
||||
case NLMSG_ERROR:
|
||||
{
|
||||
struct nlmsgerr* err = NLMSG_DATA(hdr);
|
||||
|
||||
if (err->error)
|
||||
{
|
||||
if (-err->error == EEXIST)
|
||||
{ /* do not report existing routes */
|
||||
free(out);
|
||||
return ALREADY_DONE;
|
||||
}
|
||||
if (-err->error == ESRCH)
|
||||
{ /* do not report missing entries */
|
||||
free(out);
|
||||
return NOT_FOUND;
|
||||
}
|
||||
DBG1(DBG_KNL, "received netlink error: %s (%d)",
|
||||
strerror(-err->error), -err->error);
|
||||
free(out);
|
||||
return FAILED;
|
||||
}
|
||||
free(out);
|
||||
return SUCCESS;
|
||||
}
|
||||
default:
|
||||
hdr = NLMSG_NEXT(hdr, len);
|
||||
continue;
|
||||
case NLMSG_DONE:
|
||||
break;
|
||||
}
|
||||
break;
|
||||
}
|
||||
DBG1(DBG_KNL, "netlink request not acknowledged");
|
||||
free(out);
|
||||
return FAILED;
|
||||
}
|
||||
|
||||
METHOD(netlink_socket_t, destroy, void,
|
||||
private_netlink_socket_t *this)
|
||||
{
|
||||
if (this->socket != -1)
|
||||
{
|
||||
if (this->parallel)
|
||||
{
|
||||
lib->watcher->remove(lib->watcher, this->socket);
|
||||
}
|
||||
close(this->socket);
|
||||
}
|
||||
this->entries->destroy(this->entries);
|
||||
this->mutex->destroy(this->mutex);
|
||||
free(this);
|
||||
}
|
||||
|
||||
/**
|
||||
* Described in header.
|
||||
*/
|
||||
netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names,
|
||||
bool parallel)
|
||||
{
|
||||
private_netlink_socket_t *this;
|
||||
struct sockaddr_nl addr = {
|
||||
.nl_family = AF_NETLINK,
|
||||
};
|
||||
|
||||
INIT(this,
|
||||
.public = {
|
||||
.send = _netlink_send,
|
||||
.send_ack = _netlink_send_ack,
|
||||
.destroy = _destroy,
|
||||
},
|
||||
.seq = 200,
|
||||
.mutex = mutex_create(MUTEX_TYPE_RECURSIVE),
|
||||
.socket = socket(AF_NETLINK, SOCK_RAW, protocol),
|
||||
.entries = hashtable_create(hashtable_hash_ptr, hashtable_equals_ptr, 4),
|
||||
.protocol = protocol,
|
||||
.names = names,
|
||||
.buflen = lib->settings->get_int(lib->settings,
|
||||
"%s.plugins.kernel-netlink.buflen", 0, lib->ns),
|
||||
.timeout = lib->settings->get_int(lib->settings,
|
||||
"%s.plugins.kernel-netlink.timeout", 0, lib->ns),
|
||||
.retries = lib->settings->get_int(lib->settings,
|
||||
"%s.plugins.kernel-netlink.retries", 0, lib->ns),
|
||||
.ignore_retransmit_errors = lib->settings->get_bool(lib->settings,
|
||||
"%s.plugins.kernel-netlink.ignore_retransmit_errors",
|
||||
FALSE, lib->ns),
|
||||
.parallel = parallel,
|
||||
);
|
||||
|
||||
if (!this->buflen)
|
||||
{
|
||||
long pagesize = sysconf(_SC_PAGESIZE);
|
||||
if (pagesize == -1)
|
||||
{
|
||||
pagesize = 4096;
|
||||
}
|
||||
/* base this on NLMSG_GOODSIZE */
|
||||
this->buflen = min(pagesize, 8192);
|
||||
}
|
||||
if (this->socket == -1)
|
||||
{
|
||||
DBG1(DBG_KNL, "unable to create netlink socket");
|
||||
destroy(this);
|
||||
return NULL;
|
||||
}
|
||||
if (bind(this->socket, (struct sockaddr*)&addr, sizeof(addr)))
|
||||
{
|
||||
DBG1(DBG_KNL, "unable to bind netlink socket");
|
||||
destroy(this);
|
||||
return NULL;
|
||||
}
|
||||
if (this->parallel)
|
||||
{
|
||||
lib->watcher->add(lib->watcher, this->socket, WATCHER_READ, watch, this);
|
||||
}
|
||||
|
||||
return &this->public;
|
||||
}
|
||||
|
||||
/**
|
||||
* Described in header.
|
||||
*/
|
||||
void netlink_add_attribute(struct nlmsghdr *hdr, int rta_type, chunk_t data,
|
||||
size_t buflen)
|
||||
{
|
||||
struct rtattr *rta;
|
||||
|
||||
if (NLMSG_ALIGN(hdr->nlmsg_len) + RTA_LENGTH(data.len) > buflen)
|
||||
{
|
||||
DBG1(DBG_KNL, "unable to add attribute, buffer too small");
|
||||
return;
|
||||
}
|
||||
|
||||
rta = (struct rtattr*)(((char*)hdr) + NLMSG_ALIGN(hdr->nlmsg_len));
|
||||
rta->rta_type = rta_type;
|
||||
rta->rta_len = RTA_LENGTH(data.len);
|
||||
memcpy(RTA_DATA(rta), data.ptr, data.len);
|
||||
hdr->nlmsg_len = NLMSG_ALIGN(hdr->nlmsg_len) + rta->rta_len;
|
||||
}
|
||||
|
||||
/**
|
||||
* Described in header.
|
||||
*/
|
||||
void* netlink_reserve(struct nlmsghdr *hdr, int buflen, int type, int len)
|
||||
{
|
||||
struct rtattr *rta;
|
||||
|
||||
if (NLMSG_ALIGN(hdr->nlmsg_len) + RTA_LENGTH(len) > buflen)
|
||||
{
|
||||
DBG1(DBG_KNL, "unable to add attribute, buffer too small");
|
||||
return NULL;
|
||||
}
|
||||
|
||||
rta = ((void*)hdr) + NLMSG_ALIGN(hdr->nlmsg_len);
|
||||
rta->rta_type = type;
|
||||
rta->rta_len = RTA_LENGTH(len);
|
||||
hdr->nlmsg_len = NLMSG_ALIGN(hdr->nlmsg_len) + rta->rta_len;
|
||||
|
||||
return RTA_DATA(rta);
|
||||
}
|
||||
Reference in New Issue
Block a user