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/**
Copyright (C) 2015 clowwindy
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 3 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// Extracted from ShadowVPN project, with some minor modifications.
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <net/if_utun.h>
#include <netinet/ip.h>
#include <sys/ioctl.h>
#include <sys/kern_control.h>
#include <sys/sys_domain.h>
#include <sys/uio.h>
#include <unistd.h>
#include "tun.h"
int tun_alloc(const char *dev_name, int threads, int *fds) {
struct ctl_info ctlInfo;
struct sockaddr_ctl sc;
int fd, utun_num;
if (!dev_name || sscanf(dev_name, "utun%d", &utun_num) != 1)
return -1;
memset(&ctlInfo, 0, sizeof(ctlInfo));
if (strlcpy(ctlInfo.ctl_name,
UTUN_CONTROL_NAME,
sizeof(ctlInfo.ctl_name)) >= sizeof(ctlInfo.ctl_name)) {
return -1;
}
fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
if (fd < 0)
return -1;
if (ioctl(fd, CTLIOCGINFO, &ctlInfo) < 0) {
close(fd);
return -1;
}
sc.sc_id = ctlInfo.ctl_id;
sc.sc_len = sizeof(sc);
sc.sc_family = AF_SYSTEM;
sc.ss_sysaddr = AF_SYS_CONTROL;
sc.sc_unit = utun_num + 1;
if (connect(fd, (struct sockaddr*)&sc, sizeof(sc)) < 0) {
close(fd);
return -1;
}
*fds = fd;
return 1;
}
inline int utun_modified_len(int len) {
if (len > 0)
return (len > sizeof(u_int32_t)) ? len - sizeof(u_int32_t) : 0;
else
return len;
}
int utun_read(int fd, void *buf, size_t len) {
u_int32_t type;
struct iovec iv[2];
iv[0].iov_base = &type;
iv[0].iov_len = sizeof(type);
iv[1].iov_base = buf;
iv[1].iov_len = len;
return utun_modified_len(readv(fd, iv, 2));
}
int utun_write(int fd, void *buf, size_t len) {
u_int32_t type;
struct iovec iv[2];
struct ip *iph;
iph = (struct ip *) buf;
if (iph->ip_v == 6)
type = htonl(AF_INET6);
else
type = htonl(AF_INET);
iv[0].iov_base = &type;
iv[0].iov_len = sizeof(type);
iv[1].iov_base = buf;
iv[1].iov_len = len;
return utun_modified_len(writev(fd, iv, 2));
}
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