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// SPDX-License-Identifier: EUPL-1.2
// SPDX-FileCopyrightText: 2022 Alyssa Ross <hi@alyssa.is>
#include <err.h>
#include <fcntl.h>
#include <net/if.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/if_tun.h>
#include <linux/sockios.h>
// ifr_name doesn't have to be null terminated.
#pragma GCC diagnostic ignored "-Wstringop-truncation"
int if_up(const char *name)
{
struct ifreq req;
int fd, r = -1;
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
strncpy(req.ifr_name, name, IFNAMSIZ);
if (ioctl(fd, SIOCGIFFLAGS, &req) == -1)
goto out;
req.ifr_flags |= IFF_UP;
r = ioctl(fd, SIOCSIFFLAGS, &req);
out:
close(fd);
return r;
}
int if_rename(const char *name, const char *newname)
{
int fd, r;
struct ifreq ifr;
strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
strncpy(ifr.ifr_newname, newname, sizeof ifr.ifr_newname);
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
r = ioctl(fd, SIOCSIFNAME, &ifr);
close(fd);
return r;
}
int if_down(const char *name)
{
struct ifreq ifr;
int fd, r = -1;
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
strncpy(ifr.ifr_name, name, IFNAMSIZ);
if (ioctl(fd, SIOCGIFFLAGS, &ifr) == -1)
goto out;
ifr.ifr_flags &= ~IFF_UP;
r = ioctl(fd, SIOCSIFFLAGS, &ifr);
out:
close(fd);
return r;
}
int bridge_add(const char *name)
{
int fd, r;
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
r = ioctl(fd, SIOCBRADDBR, name);
close(fd);
return r;
}
int bridge_add_if(const char *brname, const char *ifname)
{
struct ifreq ifr;
int fd, r;
strncpy(ifr.ifr_name, brname, IFNAMSIZ);
if (!(ifr.ifr_ifindex = if_nametoindex(ifname)))
return -1;
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
r = ioctl(fd, SIOCBRADDIF, &ifr);
close(fd);
return r;
}
int bridge_remove_if(const char *brname, const char *ifname)
{
struct ifreq ifr;
int fd, r;
strncpy(ifr.ifr_name, brname, IFNAMSIZ);
if (!(ifr.ifr_ifindex = if_nametoindex(ifname)))
return -1;
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
r = ioctl(fd, SIOCBRDELIF, &ifr);
close(fd);
return r;
}
int bridge_delete(const char *name)
{
int fd, r;
if (if_down(name) == -1)
warn("setting %s down", name);
if ((fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0)) == -1)
return -1;
r = ioctl(fd, SIOCBRDELBR, name);
close(fd);
return r;
}
int tap_open(const char *name, int flags)
{
struct ifreq ifr;
int fd;
if ((fd = open("/dev/net/tun", O_RDWR)) == -1)
return -1;
strncpy(ifr.ifr_name, name, IFNAMSIZ);
ifr.ifr_flags = IFF_TAP|flags;
if (!ioctl(fd, TUNSETIFF, &ifr))
return fd;
close(fd);
return -1;
}
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