--- /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;
+}
projects / tinc / blobdiff