ndhc/ifchd/linux.c

339 lines
9.6 KiB
C
Raw Normal View History

2010-11-12 14:32:18 +05:30
/* linux.c - ifchd Linux-specific functions
*
* Copyright (c) 2004-2013 Nicholas J. Kain <njkain at gmail dot com>
* All rights reserved.
2010-11-12 14:32:18 +05:30
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
2010-11-12 14:32:18 +05:30
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
2010-11-12 14:32:18 +05:30
*
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
2010-11-12 14:32:18 +05:30
*/
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define __USE_GNU 1
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/route.h>
#include <net/if.h>
#include <netpacket/packet.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#include "ifchd-defines.h"
2010-11-12 14:32:18 +05:30
#include "log.h"
#include "ifch_proto.h"
2010-11-12 16:12:07 +05:30
#include "strl.h"
2010-11-12 14:32:18 +05:30
extern struct ifchd_client clients[SOCK_QUEUE];
static size_t numokif;
static char okif[MAX_IFACES][IFNAMSIZ];
2010-11-12 14:32:18 +05:30
/* Adds to the list of interface names ifchd clients are allowed to change. */
void add_permitted_if(char *s)
{
if (numokif >= MAX_IFACES)
return;
2013-05-06 16:37:54 +05:30
strnkcpy(okif[numokif++], s, IFNAMSIZ);
2010-11-12 14:32:18 +05:30
}
/* Checks if changes are permitted to a given interface. 1 == allowed */
static int is_permitted(char *name)
{
/* If empty, permit all. */
if (!numokif)
return 1;
2010-11-12 14:32:18 +05:30
if (!name || strlen(name) == 0)
return 0;
for (size_t i = 0; i < numokif; ++i) {
if (strcmp(name, okif[i]) == 0)
return 1;
2010-11-12 14:32:18 +05:30
}
log_line("attempt to modify interface %s denied", name);
2010-11-12 14:32:18 +05:30
return 0;
}
/* Verify that peer is authorized to connect (return 1 on success). */
int authorized_peer(int sk, pid_t pid, uid_t uid, gid_t gid)
{
int ret = 0;
unsigned int cl;
struct ucred cr;
/* No credentials to verify. */
if ( !(pid || uid || gid) )
return 1;
2010-11-12 14:32:18 +05:30
/* Verify that peer has authorized uid/gid/pid. */
cl = sizeof(struct ucred);
if (getsockopt(sk, SOL_SOCKET, SO_PEERCRED, &cr, &cl) != -1) {
if ((pid == 0 || cr.pid == pid) ||
(uid == 0 || cr.uid == uid) ||
(gid == 0 || cr.gid == gid))
ret = 1;
2010-11-12 14:32:18 +05:30
} else
log_line("getsockopt returned an error: %s", strerror(errno));
2010-11-12 14:32:18 +05:30
return ret;
}
void perform_interface(struct ifchd_client *cl, const char *str, size_t len)
2010-11-12 14:32:18 +05:30
{
if (!str)
return;
2010-11-12 14:32:18 +05:30
/* Update interface name. */
memset(cl->ifnam, '\0', IFNAMSIZ);
2013-05-06 16:37:54 +05:30
strnkcpy(cl->ifnam, str, IFNAMSIZ);
log_line("Subsequent commands alter interface: '%s'", str);
2010-11-12 14:32:18 +05:30
}
static int set_if_flag(struct ifchd_client *cl, short flag)
2010-11-12 14:32:18 +05:30
{
int fd, ret = -1;
struct ifreq ifrt;
if (!is_permitted(cl->ifnam))
goto out0;
2010-11-12 14:32:18 +05:30
fd = socket(AF_INET, SOCK_DGRAM, 0);
2010-11-12 14:32:18 +05:30
if (fd == -1) {
log_line("%s: (set_if_flag) failed to open interface socket: %s",
cl->ifnam, strerror(errno));
goto out0;
2010-11-12 14:32:18 +05:30
}
2013-05-06 16:37:54 +05:30
strnkcpy(ifrt.ifr_name, cl->ifnam, IFNAMSIZ);
2010-11-12 14:32:18 +05:30
if (ioctl(fd, SIOCGIFFLAGS, &ifrt) < 0) {
log_line("%s: unknown interface: %s", cl->ifnam, strerror(errno));
goto out1;
2010-11-12 14:32:18 +05:30
}
if (((ifrt.ifr_flags & flag ) ^ flag) & flag) {
2013-05-06 16:37:54 +05:30
strnkcpy(ifrt.ifr_name, cl->ifnam, IFNAMSIZ);
ifrt.ifr_flags |= flag;
if (ioctl(fd, SIOCSIFFLAGS, &ifrt) < 0) {
log_line("%s: failed to set interface flags: %s",
cl->ifnam, strerror(errno));
goto out1;
}
} else
ret = 0;
2010-11-12 14:32:18 +05:30
out1:
2010-11-12 14:32:18 +05:30
close(fd);
out0:
2010-11-12 14:32:18 +05:30
return ret;
}
/* Sets IP address on an interface and brings it up. */
void perform_ip(struct ifchd_client *cl, const char *str, size_t len)
2010-11-12 14:32:18 +05:30
{
int fd;
struct in_addr ipaddr;
struct ifreq ifrt;
struct sockaddr_in sin;
if (!str)
return;
if (!is_permitted(cl->ifnam))
return;
if (!inet_pton(AF_INET, str, &ipaddr))
return;
if (set_if_flag(cl, (IFF_UP | IFF_RUNNING)))
return;
2010-11-12 14:32:18 +05:30
2013-05-06 16:37:54 +05:30
strnkcpy(ifrt.ifr_name, cl->ifnam, IFNAMSIZ);
2010-11-12 14:32:18 +05:30
memset(&sin, 0, sizeof(struct sockaddr));
sin.sin_family = AF_INET;
sin.sin_addr = ipaddr;
memcpy(&ifrt.ifr_addr, &sin, sizeof(struct sockaddr));
fd = socket(AF_INET, SOCK_DGRAM, 0);
2010-11-12 14:32:18 +05:30
if (fd == -1) {
log_line("%s: (perform_ip) failed to open interface socket: %s",
cl->ifnam, strerror(errno));
return;
2010-11-12 14:32:18 +05:30
}
if (ioctl(fd, SIOCSIFADDR, &ifrt) < 0)
log_line("%s: failed to configure IP: %s",
cl->ifnam, strerror(errno));
else
log_line("Interface IP set to: '%s'", str);
2010-11-12 14:32:18 +05:30
close(fd);
}
/* Sets the subnet mask on an interface. */
void perform_subnet(struct ifchd_client *cl, const char *str, size_t len)
2010-11-12 14:32:18 +05:30
{
int fd;
struct in_addr subnet;
struct ifreq ifrt;
struct sockaddr_in sin;
if (!str)
return;
if (!is_permitted(cl->ifnam))
return;
if (!inet_pton(AF_INET, str, &subnet))
return;
2010-11-12 14:32:18 +05:30
2013-05-06 16:37:54 +05:30
strnkcpy(ifrt.ifr_name, cl->ifnam, IFNAMSIZ);
2010-11-12 14:32:18 +05:30
memset(&sin, 0, sizeof(struct sockaddr));
sin.sin_family = AF_INET;
sin.sin_addr = subnet;
memcpy(&ifrt.ifr_addr, &sin, sizeof(struct sockaddr));
fd = socket(AF_INET, SOCK_DGRAM, 0);
2010-11-12 14:32:18 +05:30
if (fd == -1) {
log_line("%s: (perform_ip) failed to open interface socket: %s",
cl->ifnam, strerror(errno));
return;
2010-11-12 14:32:18 +05:30
}
if (ioctl(fd, SIOCSIFNETMASK, &ifrt) < 0) {
sin.sin_addr.s_addr = 0xffffffff;
if (ioctl(fd, SIOCSIFNETMASK, &ifrt) < 0)
log_line("%s: failed to configure subnet: %s",
cl->ifnam, strerror(errno));
} else
log_line("Interface subnet set to: '%s'", str);
2010-11-12 14:32:18 +05:30
close(fd);
}
void perform_router(struct ifchd_client *cl, const char *str, size_t len)
2010-11-12 14:32:18 +05:30
{
struct rtentry rt;
struct sockaddr_in *dest;
struct sockaddr_in *gateway;
struct sockaddr_in *mask;
struct in_addr router;
int fd;
if (!str)
return;
if (!is_permitted(cl->ifnam))
return;
if (!inet_pton(AF_INET, str, &router))
return;
2010-11-12 14:32:18 +05:30
memset(&rt, 0, sizeof(struct rtentry));
dest = (struct sockaddr_in *) &rt.rt_dst;
dest->sin_family = AF_INET;
dest->sin_addr.s_addr = 0x00000000;
gateway = (struct sockaddr_in *) &rt.rt_gateway;
gateway->sin_family = AF_INET;
gateway->sin_addr = router;
mask = (struct sockaddr_in *) &rt.rt_genmask;
mask->sin_family = AF_INET;
mask->sin_addr.s_addr = 0x00000000;
rt.rt_flags = RTF_UP | RTF_GATEWAY;
if (mask->sin_addr.s_addr == 0xffffffff) rt.rt_flags |= RTF_HOST;
rt.rt_dev = cl->ifnam;
2010-11-12 14:32:18 +05:30
rt.rt_metric = 1;
fd = socket(AF_INET, SOCK_DGRAM, 0);
2010-11-12 14:32:18 +05:30
if (fd == -1) {
log_line("%s: (perform_router) failed to open interface socket: %s",
cl->ifnam, strerror(errno));
return;
2010-11-12 14:32:18 +05:30
}
if (ioctl(fd, SIOCADDRT, &rt)) {
if (errno != EEXIST)
log_line("%s: failed to set route: %s",
cl->ifnam, strerror(errno));
} else
log_line("Gateway router set to: '%s'", str);
2010-11-12 14:32:18 +05:30
close(fd);
}
void perform_mtu(struct ifchd_client *cl, const char *str, size_t len)
2010-11-12 14:32:18 +05:30
{
int fd;
unsigned int mtu;
struct ifreq ifrt;
if (!str)
return;
if (!is_permitted(cl->ifnam))
return;
2010-11-12 14:32:18 +05:30
mtu = strtol(str, NULL, 10);
// Minimum MTU for physical IPv4 links is 576 octets.
if (mtu < 576)
return;
2010-11-12 14:32:18 +05:30
ifrt.ifr_mtu = mtu;
2013-05-06 16:37:54 +05:30
strnkcpy(ifrt.ifr_name, cl->ifnam, IFNAMSIZ);
2010-11-12 14:32:18 +05:30
fd = socket(AF_INET, SOCK_DGRAM, 0);
2010-11-12 14:32:18 +05:30
if (fd == -1) {
log_line("%s: (perform_mtu) failed to open interface socket: %s",
cl->ifnam, strerror(errno));
return;
2010-11-12 14:32:18 +05:30
}
if (ioctl(fd, SIOCSIFMTU, &ifrt) < 0)
log_line("%s: failed to set MTU (%d): %s", cl->ifnam, mtu,
strerror(errno));
else
log_line("MTU set to: '%s'", str);
2010-11-12 14:32:18 +05:30
close(fd);
}
void perform_broadcast(struct ifchd_client *cl, const char *str, size_t len)
2010-11-12 14:32:18 +05:30
{
int fd;
struct in_addr broadcast;
struct ifreq ifrt;
struct sockaddr_in sin;
if (!str)
return;
if (!is_permitted(cl->ifnam))
return;
if (!inet_pton(AF_INET, str, &broadcast))
return;
2010-11-12 14:32:18 +05:30
2013-05-06 16:37:54 +05:30
strnkcpy(ifrt.ifr_name, cl->ifnam, IFNAMSIZ);
2010-11-12 14:32:18 +05:30
memset(&sin, 0, sizeof(struct sockaddr));
sin.sin_family = AF_INET;
sin.sin_addr = broadcast;
memcpy(&ifrt.ifr_addr, &sin, sizeof(struct sockaddr));
fd = socket(AF_INET, SOCK_DGRAM, 0);
2010-11-12 14:32:18 +05:30
if (fd == -1) {
log_line("%s: (perform_broadcast) failed to open interface socket: %s", cl->ifnam, strerror(errno));
return;
2010-11-12 14:32:18 +05:30
}
if (ioctl(fd, SIOCSIFBRDADDR, &ifrt) < 0)
log_line("%s: failed to set broadcast: %s",
cl->ifnam, strerror(errno));
else
log_line("Broadcast address set to: '%s'", str);
2010-11-12 14:32:18 +05:30
close(fd);
}