/*
* libipq.c
*
* IPQ userspace library.
*
* Please note that this library is still developmental, and there may
* be some API changes.
*
* Author: James Morris <jmorris@intercode.com.au>
*
* 07-11-2001 Modified by Fernando Anton to add support for IPv6.
*
* Copyright (c) 2000-2001 Netfilter Core Team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <libipq/libipq.h>
#include <netinet/in.h>
#include <linux/netfilter.h>
/****************************************************************************
*
* Private interface
*
****************************************************************************/
enum {
IPQ_ERR_NONE = 0,
IPQ_ERR_IMPL,
IPQ_ERR_HANDLE,
IPQ_ERR_SOCKET,
IPQ_ERR_BIND,
IPQ_ERR_BUFFER,
IPQ_ERR_RECV,
IPQ_ERR_NLEOF,
IPQ_ERR_ADDRLEN,
IPQ_ERR_STRUNC,
IPQ_ERR_RTRUNC,
IPQ_ERR_NLRECV,
IPQ_ERR_SEND,
IPQ_ERR_SUPP,
IPQ_ERR_RECVBUF,
IPQ_ERR_TIMEOUT,
IPQ_ERR_PROTOCOL
};
#define IPQ_MAXERR IPQ_ERR_PROTOCOL
struct ipq_errmap_t {
int errcode;
char *message;
} ipq_errmap[] = {
{ IPQ_ERR_NONE, "Unknown error" },
{ IPQ_ERR_IMPL, "Implementation error" },
{ IPQ_ERR_HANDLE, "Unable to create netlink handle" },
{ IPQ_ERR_SOCKET, "Unable to create netlink socket" },
{ IPQ_ERR_BIND, "Unable to bind netlink socket" },
{ IPQ_ERR_BUFFER, "Unable to allocate buffer" },
{ IPQ_ERR_RECV, "Failed to receive netlink message" },
{ IPQ_ERR_NLEOF, "Received EOF on netlink socket" },
{ IPQ_ERR_ADDRLEN, "Invalid peer address length" },
{ IPQ_ERR_STRUNC, "Sent message truncated" },
{ IPQ_ERR_RTRUNC, "Received message truncated" },
{ IPQ_ERR_NLRECV, "Received error from netlink" },
{ IPQ_ERR_SEND, "Failed to send netlink message" },
{ IPQ_ERR_SUPP, "Operation not supported" },
{ IPQ_ERR_RECVBUF, "Receive buffer size invalid" },
{ IPQ_ERR_TIMEOUT, "Timeout"},
{ IPQ_ERR_PROTOCOL, "Invalid protocol specified" }
};
static int ipq_errno = IPQ_ERR_NONE;
static ssize_t ipq_netlink_sendto(const struct ipq_handle *h,
const void *msg, size_t len);
static ssize_t ipq_netlink_recvfrom(const struct ipq_handle *h,
unsigned char *buf, size_t len,
int timeout);
static ssize_t ipq_netlink_sendmsg(const struct ipq_handle *h,
const struct msghdr *msg,
unsigned int flags);
static char *ipq_strerror(int errcode);
static ssize_t ipq_netlink_sendto(const struct ipq_handle *h,
const void *msg, size_t len)
{
int status = sendto(h->fd, msg, len, 0,
(struct sockaddr *)&h->peer, sizeof(h->peer));
if (status < 0)
ipq_errno = IPQ_ERR_SEND;
return status;
}
static ssize_t ipq_netlink_sendmsg(const struct ipq_handle *h,
const struct msghdr *msg,
unsigned int flags)
{
int status = sendmsg(h->fd, msg, flags);
if (status < 0)
ipq_errno = IPQ_ERR_SEND;
return status;
}
static ssize_t ipq_netlink_recvfrom(const struct ipq_handle *h,
unsigned char *buf, size_t len,
int timeout)
{
unsigned int addrlen;
int status;
struct nlmsghdr *nlh;
if (len < sizeof(struct nlmsgerr)) {
ipq_errno = IPQ_ERR_RECVBUF;
return -1;
}
addrlen = sizeof(h->peer);
if (timeout != 0) {
int ret;
struct timeval tv;
fd_set read_fds;
if (timeout < 0) {
/* non-block non-timeout */
tv.tv_sec = 0;
tv.tv_usec = 0;
} else {
tv.tv_sec = timeout / 1000000;
tv.tv_usec = timeout % 1000000;
}
FD_ZERO(&read_fds);
FD_SET(h->fd, &read_fds);
ret = select(h->fd+1, &read_fds, NULL, NULL, &tv);
if (ret < 0) {
if (errno == EINTR) {
return 0;
} else {
ipq_errno = IPQ_ERR_RECV;
return -1;
}
}
if (!FD_ISSET(h->fd, &read_fds)) {
ipq_errno = IPQ_ERR_TIMEOUT;
return 0;
}
}
status = recvfrom(h->fd, buf, len, 0,
(struct sockaddr *)&h->peer, &addrlen);
if (status < 0) {
ipq_errno = IPQ_ERR_RECV;
return status;
}
if (addrlen != sizeof(h->peer)) {
ipq_errno = IPQ_ERR_RECV;
return -1;
}
if (h->peer.nl_pid != 0) {
ipq_errno = IPQ_ERR_RECV;
return -1;
}
if (status == 0) {
ipq_errno = IPQ_ERR_NLEOF;
return -1;
}
nlh = (struct nlmsghdr *)buf;
if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > status) {
ipq_errno = IPQ_ERR_RTRUNC;
return -1;
}
return status;
}
static char *ipq_strerror(int errcode)
{
if (errcode < 0 || errcode > IPQ_MAXERR)
errcode = IPQ_ERR_IMPL;
return ipq_errmap[errcode].message;
}
/****************************************************************************
*
* Public interface
*
****************************************************************************/
/*
* Create and initialise an ipq handle.
*/
struct ipq_handle *ipq_create_handle(uint32_t flags, uint32_t protocol)
{
int status;
struct ipq_handle *h;
h = (struct ipq_handle *)malloc(sizeof(struct ipq_handle));
if (h == NULL) {
ipq_errno = IPQ_ERR_HANDLE;
return NULL;
}
memset(h, 0, sizeof(struct ipq_handle));
if (protocol == NFPROTO_IPV4)
h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_FIREWALL);
else if (protocol == NFPROTO_IPV6)
h->fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_IP6_FW);
else {
ipq_errno = IPQ_ERR_PROTOCOL;
free(h);
return NULL;
}
if (h->fd == -1) {
ipq_errno = IPQ_ERR_SOCKET;
free(h);
return NULL;
}
memset(&h->local, 0, sizeof(struct sockaddr_nl));
h->local.nl_family = AF_NETLINK;
h->local.nl_pid = getpid();
h->local.nl_groups = 0;
status = bind(h->fd, (struct sockaddr *)&h->local, sizeof(h->local));
if (status == -1) {
ipq_errno = IPQ_ERR_BIND;
close(h->fd);
free(h);
return NULL;
}
memset(&h->peer, 0, sizeof(struct sockaddr_nl));
h->peer.nl_family = AF_NETLINK;
h->peer.nl_pid = 0;
h->peer.nl_groups = 0;
return h;
}
/*
* No error condition is checked here at this stage, but it may happen
* if/when reliable messaging is implemented.
*/
int ipq_destroy_handle(struct ipq_handle *h)
{
if (h) {
close(h->fd);
free(h);
}
return 0;
}
int ipq_set_mode(const struct ipq_handle *h,
uint8_t mode, size_t range)
{
struct {
struct nlmsghdr nlh;
ipq_peer_msg_t pm;
} req;
memset(&req, 0, sizeof(req));
req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(req));
req.nlh.nlmsg_flags = NLM_F_REQUEST;
req.nlh.nlmsg_type = IPQM_MODE;
req.nlh.nlmsg_pid = h->local.nl_pid;
req.pm.msg.mode.value = mode;
req.pm.msg.mode.range = range;
return ipq_netlink_sendto(h, (void *)&req, req.nlh.nlmsg_len);
}
/*
* timeout is in microseconds (1 second is 1000000 (1 million) microseconds)
*
*/
ssize_t ipq_read(const struct ipq_handle *h,
unsigned char *buf, size_t len, int timeout)
{
return ipq_netlink_recvfrom(h, buf, len, timeout);
}
int ipq_message_type(const unsigned char *buf)
{
return ((struct nlmsghdr*)buf)->nlmsg_type;
}
int ipq_get_msgerr(const unsigned char *buf)
{
struct nlmsghdr *h = (struct nlmsghdr *)buf;
struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
return -err->error;
}
ipq_packet_msg_t *ipq_get_packet(const unsigned char *buf)
{
return NLMSG_DATA((struct nlmsghdr *)(buf));
}
int ipq_set_verdict(const struct ipq_handle *h,
ipq_id_t id,
unsigned int verdict,
size_t data_len,
unsigned char *buf)
{
unsigned char nvecs;
size_t tlen;
struct nlmsghdr nlh;
ipq_peer_msg_t pm;
struct iovec iov[3];
struct msghdr msg;
memset(&nlh, 0, sizeof(nlh));
nlh.nlmsg_flags = NLM_F_REQUEST;
nlh.nlmsg_type = IPQM_VERDICT;
nlh.nlmsg_pid = h->local.nl_pid;
memset(&pm, 0, sizeof(pm));
pm.msg.verdict.value = verdict;
pm.msg.verdict.id = id;
pm.msg.verdict.data_len = data_len;
iov[0].iov_base = &nlh;
iov[0].iov_len = sizeof(nlh);
iov[1].iov_base = ±
iov[1].iov_len = sizeof(pm);
tlen = sizeof(nlh) + sizeof(pm);
nvecs = 2;
if (data_len && buf) {
iov[2].iov_base = buf;
iov[2].iov_len = data_len;
tlen += data_len;
nvecs++;
}
msg.msg_name = (void *)&h->peer;
msg.msg_namelen = sizeof(h->peer);
msg.msg_iov = iov;
msg.msg_iovlen = nvecs;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
nlh.nlmsg_len = tlen;
return ipq_netlink_sendmsg(h, &msg, 0);
}
/* Not implemented yet */
int ipq_ctl(const struct ipq_handle *h, int request, ...)
{
return 1;
}
char *ipq_errstr(void)
{
return ipq_strerror(ipq_errno);
}
void ipq_perror(const char *s)
{
if (s)
fputs(s, stderr);
else
fputs("ERROR", stderr);
if (ipq_errno)
fprintf(stderr, ": %s", ipq_errstr());
if (errno)
fprintf(stderr, ": %s", strerror(errno));
fputc('\n', stderr);
}