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openggsn/ggsn/tun.c

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/*
* TUN interface functions.
* Copyright (C) 2002, 2003 Mondru AB.
*
* The contents of this file may be used under the terms of the GNU
* General Public License Version 2, provided that the above copyright
* notice and this permission notice is included in all copies or
* substantial portions of the software.
*
* The initial developer of the original code is
* Jens Jakobsen <jj@openggsn.org>
*
* Contributor(s):
*
*/
/*
* tun.c: Contains all TUN functionality. Is able to handle multiple
* tunnels in the same program. Each tunnel is identified by the struct,
* which is passed to functions.
*
*/
#include <syslog.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <errno.h>
#include <linux/if_tun.h>
#include <net/route.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include "tun.h"
#include "syserr.h"
int tun_nlattr(struct nlmsghdr *n, int nsize, int type, void *d, int dlen)
{
int len = RTA_LENGTH(dlen);
int alen = NLMSG_ALIGN(n->nlmsg_len);
struct rtattr *rta = (struct rtattr*) (((void*)n) + alen);
if (alen + len > nsize)
return -1;
rta->rta_len = len;
rta->rta_type = type;
memcpy(RTA_DATA(rta), d, dlen);
n->nlmsg_len = alen + len;
return 0;
}
int tun_gifindex(struct tun_t *this, int *index) {
struct ifreq ifr;
int fd;
memset (&ifr, '\0', sizeof (ifr));
ifr.ifr_addr.sa_family = AF_INET;
ifr.ifr_dstaddr.sa_family = AF_INET;
ifr.ifr_netmask.sa_family = AF_INET;
strncpy(ifr.ifr_name, this->devname, IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ-1] = 0; /* Make sure to terminate */
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"socket() failed");
}
if (ioctl(fd, SIOCGIFINDEX, &ifr)) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"ioctl() failed");
close(fd);
return -1;
}
close(fd);
*index = ifr.ifr_ifindex;
return 0;
}
int tun_sifflags(struct tun_t *this, int flags) {
struct ifreq ifr;
int fd;
memset (&ifr, '\0', sizeof (ifr));
ifr.ifr_flags = flags;
strncpy(ifr.ifr_name, this->devname, IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ-1] = 0; /* Make sure to terminate */
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"socket() failed");
}
if (ioctl(fd, SIOCSIFFLAGS, &ifr)) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"ioctl(SIOCSIFFLAGS) failed");
close(fd);
return -1;
}
close(fd);
return 0;
}
/* Currently unused */
int tun_addroute2(struct tun_t *this,
struct in_addr *dst,
struct in_addr *gateway,
struct in_addr *mask) {
struct {
struct nlmsghdr n;
struct rtmsg r;
char buf[TUN_NLBUFSIZE];
} req;
struct sockaddr_nl local;
int addr_len;
int fd;
int status;
struct sockaddr_nl nladdr;
struct iovec iov;
struct msghdr msg;
memset(&req, 0, sizeof(req));
req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
req.n.nlmsg_type = RTM_NEWROUTE;
req.r.rtm_family = AF_INET;
req.r.rtm_table = RT_TABLE_MAIN;
req.r.rtm_protocol = RTPROT_BOOT;
req.r.rtm_scope = RT_SCOPE_UNIVERSE;
req.r.rtm_type = RTN_UNICAST;
tun_nlattr(&req.n, sizeof(req), RTA_DST, dst, 4);
tun_nlattr(&req.n, sizeof(req), RTA_GATEWAY, gateway, 4);
if ((fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"socket() failed");
return -1;
}
memset(&local, 0, sizeof(local));
local.nl_family = AF_NETLINK;
local.nl_groups = 0;
if (bind(fd, (struct sockaddr*)&local, sizeof(local)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"bind() failed");
close(fd);
return -1;
}
addr_len = sizeof(local);
if (getsockname(fd, (struct sockaddr*)&local, &addr_len) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"getsockname() failed");
close(fd);
return -1;
}
if (addr_len != sizeof(local)) {
sys_err(LOG_ERR, __FILE__, __LINE__, 0,
"Wrong address length %d", addr_len);
close(fd);
return -1;
}
if (local.nl_family != AF_NETLINK) {
sys_err(LOG_ERR, __FILE__, __LINE__, 0,
"Wrong address family %d", local.nl_family);
close(fd);
return -1;
}
iov.iov_base = (void*)&req.n;
iov.iov_len = req.n.nlmsg_len;
msg.msg_name = (void*)&nladdr;
msg.msg_namelen = sizeof(nladdr),
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_pid = 0;
nladdr.nl_groups = 0;
req.n.nlmsg_seq = 0;
req.n.nlmsg_flags |= NLM_F_ACK;
status = sendmsg(fd, &msg, 0); /* TODO: Error check */
close(fd);
return 0;
}
int tun_addaddr(struct tun_t *this,
struct in_addr *addr,
struct in_addr *dstaddr,
struct in_addr *netmask) {
struct {
struct nlmsghdr n;
struct ifaddrmsg i;
char buf[TUN_NLBUFSIZE];
} req;
struct sockaddr_nl local;
int addr_len;
int fd;
int status;
struct sockaddr_nl nladdr;
struct iovec iov;
struct msghdr msg;
if (!this->addrs) /* Use ioctl for first addr to make ping work */
return tun_setaddr(this, addr, dstaddr, netmask);
memset(&req, 0, sizeof(req));
req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
req.n.nlmsg_type = RTM_NEWADDR;
req.i.ifa_family = AF_INET;
req.i.ifa_prefixlen = 32; /* 32 FOR IPv4 */
req.i.ifa_flags = 0;
req.i.ifa_scope = RT_SCOPE_HOST; /* TODO or 0 */
if (tun_gifindex(this, &req.i.ifa_index)) {
return -1;
}
tun_nlattr(&req.n, sizeof(req), IFA_ADDRESS, addr, sizeof(addr));
tun_nlattr(&req.n, sizeof(req), IFA_LOCAL, dstaddr, sizeof(dstaddr));
if ((fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"socket() failed");
return -1;
}
memset(&local, 0, sizeof(local));
local.nl_family = AF_NETLINK;
local.nl_groups = 0;
if (bind(fd, (struct sockaddr*)&local, sizeof(local)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"bind() failed");
close(fd);
return -1;
}
addr_len = sizeof(local);
if (getsockname(fd, (struct sockaddr*)&local, &addr_len) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"getsockname() failed");
close(fd);
return -1;
}
if (addr_len != sizeof(local)) {
sys_err(LOG_ERR, __FILE__, __LINE__, 0,
"Wrong address length %d", addr_len);
close(fd);
return -1;
}
if (local.nl_family != AF_NETLINK) {
sys_err(LOG_ERR, __FILE__, __LINE__, 0,
"Wrong address family %d", local.nl_family);
close(fd);
return -1;
}
iov.iov_base = (void*)&req.n;
iov.iov_len = req.n.nlmsg_len;
msg.msg_name = (void*)&nladdr;
msg.msg_namelen = sizeof(nladdr),
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
memset(&nladdr, 0, sizeof(nladdr));
nladdr.nl_family = AF_NETLINK;
nladdr.nl_pid = 0;
nladdr.nl_groups = 0;
req.n.nlmsg_seq = 0;
req.n.nlmsg_flags |= NLM_F_ACK;
status = sendmsg(fd, &msg, 0); /* TODO Error check */
tun_sifflags(this, IFF_UP | IFF_RUNNING);
close(fd);
this->addrs++;
return 0;
}
int tun_setaddr(struct tun_t *this,
struct in_addr *addr,
struct in_addr *dstaddr,
struct in_addr *netmask)
{
struct ifreq ifr;
int fd;
memset (&ifr, '\0', sizeof (ifr));
ifr.ifr_addr.sa_family = AF_INET;
ifr.ifr_dstaddr.sa_family = AF_INET;
ifr.ifr_netmask.sa_family = AF_INET;
strncpy(ifr.ifr_name, this->devname, IFNAMSIZ);
ifr.ifr_name[IFNAMSIZ-1] = 0; /* Make sure to terminate */
/* Create a channel to the NET kernel. */
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"socket() failed");
return -1;
}
if (addr) { /* Set the interface address */
this->addr.s_addr = addr->s_addr;
((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr.s_addr = addr->s_addr;
if (ioctl(fd, SIOCSIFADDR, (void *) &ifr) < 0) {
if (errno != EEXIST) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"ioctl(SIOCSIFADDR) failed");
}
else {
sys_err(LOG_WARNING, __FILE__, __LINE__, errno,
"ioctl(SIOCSIFADDR): Address already exists");
}
close(fd);
return -1;
}
}
if (dstaddr) { /* Set the destination address */
this->dstaddr.s_addr = dstaddr->s_addr;
((struct sockaddr_in *) &ifr.ifr_dstaddr)->sin_addr.s_addr =
dstaddr->s_addr;
if (ioctl(fd, SIOCSIFDSTADDR, (caddr_t) &ifr) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"ioctl(SIOCSIFDSTADDR) failed");
close(fd);
return -1;
}
}
if (netmask) { /* Set the netmask */
this->netmask.s_addr = netmask->s_addr;
((struct sockaddr_in *) &ifr.ifr_netmask)->sin_addr.s_addr =
netmask->s_addr;
if (ioctl(fd, SIOCSIFNETMASK, (void *) &ifr) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"ioctl(SIOCSIFNETMASK) failed");
close(fd);
return -1;
}
}
close(fd);
this->addrs++;
return tun_sifflags(this, IFF_UP | IFF_RUNNING);
}
int tun_addroute(struct tun_t *this,
struct in_addr *dst,
struct in_addr *gateway,
struct in_addr *mask)
{
struct rtentry r;
int fd;
memset (&r, '\0', sizeof (r));
r.rt_flags = RTF_UP | RTF_GATEWAY; /* RTF_HOST not set */
/* Create a channel to the NET kernel. */
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"socket() failed");
return -1;
}
r.rt_dst.sa_family = AF_INET;
r.rt_gateway.sa_family = AF_INET;
r.rt_genmask.sa_family = AF_INET;
((struct sockaddr_in *) &r.rt_dst)->sin_addr.s_addr = dst->s_addr;
((struct sockaddr_in *) &r.rt_gateway)->sin_addr.s_addr = gateway->s_addr;
((struct sockaddr_in *) &r.rt_genmask)->sin_addr.s_addr = mask->s_addr;
if (ioctl(fd, SIOCADDRT, (void *) &r) < 0) { /* SIOCDELRT */
sys_err(LOG_ERR, __FILE__, __LINE__, errno,
"ioctl(SIOCADDRT) failed");
close(fd);
return -1;
}
close(fd);
return 0;
}
int tun_new(struct tun_t **tun)
{
struct ifreq ifr;
if (!(*tun = calloc(1, sizeof(struct tun_t)))) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno, "calloc() failed");
return EOF;
}
(*tun)->cb_ind = NULL;
(*tun)->addrs = 0;
if (((*tun)->fd = open("/dev/net/tun", O_RDWR)) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno, "open() failed");
return -1;
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TUN | IFF_NO_PI; /* Tun device, no packet info */
strncpy(ifr.ifr_name, (*tun)->devname, IFNAMSIZ);
if (ioctl((*tun)->fd, TUNSETIFF, (void *) &ifr) < 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno, "ioctl() failed");
close((*tun)->fd);
return -1;
}
ioctl((*tun)->fd, TUNSETNOCSUM, 1); /* Disable checksums */
strncpy((*tun)->devname, ifr.ifr_name, IFNAMSIZ);
(*tun)->devname[IFNAMSIZ] = 0;
return 0;
}
int tun_free(struct tun_t *tun)
{
if (close(tun->fd)) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno, "close() failed");
}
free(tun);
return 0;
}
int tun_set_cb_ind(struct tun_t *this,
int (*cb_ind) (struct tun_t *tun, void *pack, unsigned len)) {
this->cb_ind = cb_ind;
return 0;
}
int tun_decaps(struct tun_t *this)
{
unsigned char buffer[PACKET_MAX];
int status;
if ((status = read(this->fd, buffer, sizeof(buffer))) <= 0) {
sys_err(LOG_ERR, __FILE__, __LINE__, errno, "read() failed");
return -1;
}
if (this->cb_ind)
return this->cb_ind(this, buffer, status);
return 0;
}
int tun_encaps(struct tun_t *tun, void *pack, unsigned len)
{
return write(tun->fd, pack, len);
}
int tun_runscript(struct tun_t *tun, char* script) {
char buf[TUN_SCRIPTSIZE];
char snet[TUN_ADDRSIZE];
char smask[TUN_ADDRSIZE];
strncpy(snet, inet_ntoa(tun->addr), sizeof(snet));
snet[sizeof(snet)-1] = 0;
strncpy(smask, inet_ntoa(tun->netmask), sizeof(smask));
smask[sizeof(smask)-1] = 0;
/* system("ipup /dev/tun0 192.168.0.10 255.255.255.0"); */
snprintf(buf, sizeof(buf), "%s %s %s %s",
script, tun->devname, snet, smask);
buf[sizeof(buf)-1] = 0;
system(buf);
return 0;
}
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