+++ /dev/null
-/*
- * tunemu - Tun device emulation for Darwin
- * Copyright (C) 2009 Friedrich Schöller <friedrich.schoeller@gmail.com>
- *
- * 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/>.
- *
- */
-
-#include "tunemu.h"
-
-#include <sys/socket.h>
-#include <unistd.h>
-#include <sys/ioctl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <memory.h>
-#include <util.h>
-#include <pcap.h>
-#include <stdarg.h>
-#include <errno.h>
-#include <stdint.h>
-#include <stdint.h>
-#include <ctype.h>
-#include <fcntl.h>
-
-#define PPPPROTO_CTL 1
-
-#define PPP_IP 0x21
-#define PPP_IPV6 0x57
-
-#define SC_LOOP_TRAFFIC 0x00000200
-
-#define PPPIOCNEWUNIT _IOWR('t', 62, int)
-#define PPPIOCSFLAGS _IOW('t', 89, int)
-#define PPPIOCSNPMODE _IOW('t', 75, struct npioctl)
-#define PPPIOCATTCHAN _IOW('t', 56, int)
-#define PPPIOCGCHAN _IOR('t', 55, int)
-#define PPPIOCCONNECT _IOW('t', 58, int)
-#define PPPIOCGUNIT _IOR('t', 86, int)
-
-struct sockaddr_ppp
-{
- u_int8_t ppp_len;
- u_int8_t ppp_family;
- u_int16_t ppp_proto;
- u_int32_t ppp_cookie;
-};
-
-enum NPmode
-{
- NPMODE_PASS,
- NPMODE_DROP,
- NPMODE_ERROR,
- NPMODE_QUEUE
-};
-
-struct npioctl
-{
- int protocol;
- enum NPmode mode;
-};
-
-#define PPP_KEXT_PATH "/System/Library/Extensions/PPP.kext"
-
-#define ERROR_BUFFER_SIZE 1024
-
-char tunemu_error[ERROR_BUFFER_SIZE];
-
-static int pcap_use_count = 0;
-static pcap_t *pcap = NULL;
-
-static int data_buffer_length = 0;
-static char *data_buffer = NULL;
-
-static void tun_error(char *format, ...)
-{
- va_list vl;
- va_start(vl, format);
- vsnprintf(tunemu_error, ERROR_BUFFER_SIZE, format, vl);
- va_end(vl);
-}
-
-static void tun_noerror()
-{
- *tunemu_error = 0;
-}
-
-static void closeall()
-{
- int fd = getdtablesize();
- while (fd--)
- close(fd);
-
- open("/dev/null", O_RDWR, 0);
- dup(0);
- dup(0);
-}
-
-static int ppp_load_kext()
-{
- int pid = fork();
- if (pid < 0)
- {
- tun_error("fork for ppp kext: %s", strerror(errno));
- return -1;
- }
-
- if (pid == 0)
- {
- closeall();
- execle("/sbin/kextload", "kextload", PPP_KEXT_PATH, NULL, NULL);
- exit(1);
- }
-
- int status;
- while (waitpid(pid, &status, 0) < 0)
- {
- if (errno == EINTR)
- continue;
-
- tun_error("waitpid for ppp kext: %s", strerror(errno));
- return -1;
- }
-
- if (WEXITSTATUS(status) != 0)
- {
- tun_error("could not load ppp kext \"%s\"", PPP_KEXT_PATH);
- return -1;
- }
-
- tun_noerror();
- return 0;
-}
-
-static int ppp_new_instance()
-{
- // create ppp socket
- int ppp_sockfd = socket(PF_PPP, SOCK_RAW, PPPPROTO_CTL);
- if (ppp_sockfd < 0)
- {
- if (ppp_load_kext() < 0)
- return -1;
-
- ppp_sockfd = socket(PF_PPP, SOCK_RAW, PPPPROTO_CTL);
- if (ppp_sockfd < 0)
- {
- tun_error("creating ppp socket: %s", strerror(errno));
- return -1;
- }
- }
-
- // connect to ppp procotol
- struct sockaddr_ppp pppaddr;
- pppaddr.ppp_len = sizeof(struct sockaddr_ppp);
- pppaddr.ppp_family = AF_PPP;
- pppaddr.ppp_proto = PPPPROTO_CTL;
- pppaddr.ppp_cookie = 0;
- if (connect(ppp_sockfd, (struct sockaddr *)&pppaddr, sizeof(struct sockaddr_ppp)) < 0)
- {
- tun_error("connecting ppp socket: %s", strerror(errno));
- close(ppp_sockfd);
- return -1;
- }
-
- tun_noerror();
- return ppp_sockfd;
-}
-
-static int ppp_new_unit(int *unit_number)
-{
- int fd = ppp_new_instance();
- if (fd < 0)
- return -1;
-
- // create ppp unit
- if (ioctl(fd, PPPIOCNEWUNIT, unit_number) < 0)
- {
- tun_error("creating ppp unit: %s", strerror(errno));
- close(fd);
- return -1;
- }
-
- tun_noerror();
- return fd;
-}
-
-static int ppp_setup_unit(int unit_fd)
-{
- // send traffic to program
- int flags = SC_LOOP_TRAFFIC;
- if (ioctl(unit_fd, PPPIOCSFLAGS, &flags) < 0)
- {
- tun_error("setting ppp loopback mode: %s", strerror(errno));
- return -1;
- }
-
- // allow packets
- struct npioctl npi;
- npi.protocol = PPP_IP;
- npi.mode = NPMODE_PASS;
- if (ioctl(unit_fd, PPPIOCSNPMODE, &npi) < 0)
- {
- tun_error("starting ppp unit: %s", strerror(errno));
- return -1;
- }
-
- tun_noerror();
- return 0;
-}
-
-static int open_pcap()
-{
- if (pcap != NULL)
- {
- pcap_use_count++;
- return 0;
- }
-
- char errbuf[PCAP_ERRBUF_SIZE];
- pcap = pcap_open_live("lo0", BUFSIZ, 0, 1, errbuf);
- pcap_use_count = 1;
-
- if (pcap == NULL)
- {
- tun_error("opening pcap: %s", errbuf);
- return -1;
- }
-
- tun_noerror();
- return 0;
-}
-
-static void close_pcap()
-{
- if (pcap == NULL)
- return;
-
- pcap_use_count--;
- if (pcap_use_count == 0)
- {
- pcap_close(pcap);
- pcap = NULL;
- }
-}
-
-static void allocate_data_buffer(int size)
-{
- if (data_buffer_length < size)
- {
- free(data_buffer);
- data_buffer_length = size;
- data_buffer = malloc(data_buffer_length);
- }
-}
-
-static void make_device_name(tunemu_device device, int unit_number)
-{
- snprintf(device, sizeof(tunemu_device), "ppp%d", unit_number);
-}
-
-static int check_device_name(tunemu_device device)
-{
- if (strlen(device) < 4)
- return -1;
-
- int unit_number = atoi(device + 3);
- if (unit_number < 0 || unit_number > 999)
- return -1;
-
- tunemu_device compare;
- make_device_name(compare, unit_number);
-
- if (strcmp(device, compare) != 0)
- return -1;
-
- return 0;
-}
-
-int tunemu_open(tunemu_device device)
-{
- int ppp_unit_number = -1;
- if (device[0] != 0)
- {
- if (check_device_name(device) < 0)
- {
- tun_error("invalid device name \"%s\"", device);
- return -1;
- }
-
- ppp_unit_number = atoi(device + 3);
- }
-
- int ppp_unit_fd = ppp_new_unit(&ppp_unit_number);
- if (ppp_unit_fd < 0)
- return -1;
-
- if (ppp_setup_unit(ppp_unit_fd) < 0)
- {
- close(ppp_unit_fd);
- return -1;
- }
-
- if (open_pcap() < 0)
- {
- close(ppp_unit_fd);
- return -1;
- }
-
- make_device_name(device, ppp_unit_number);
-
- return ppp_unit_fd;
-}
-
-int tunemu_close(int ppp_sockfd)
-{
- int ret = close(ppp_sockfd);
-
- if (ret == 0)
- close_pcap();
-
- return ret;
-}
-
-int tunemu_read(int ppp_sockfd, char *buffer, int length)
-{
- allocate_data_buffer(length + 2);
-
- length = read(ppp_sockfd, data_buffer, length + 2);
- if (length < 0)
- {
- tun_error("reading packet: %s", strerror(errno));
- return length;
- }
- tun_noerror();
-
- length -= 2;
- if (length < 0)
- return 0;
-
- memcpy(buffer, data_buffer + 2, length);
-
- return length;
-}
-
-int tunemu_write(int ppp_sockfd, char *buffer, int length)
-{
- allocate_data_buffer(length + 4);
-
- data_buffer[0] = 0x02;
- data_buffer[1] = 0x00;
- data_buffer[2] = 0x00;
- data_buffer[3] = 0x00;
-
- memcpy(data_buffer + 4, buffer, length);
-
- if (pcap == NULL)
- {
- tun_error("pcap not open");
- return -1;
- }
-
- length = pcap_inject(pcap, data_buffer, length + 4);
- if (length < 0)
- {
- tun_error("injecting packet: %s", pcap_geterr(pcap));
- return length;
- }
- tun_noerror();
-
- length -= 4;
- if (length < 0)
- return 0;
-
- return length;
-}
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