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comparison tunnel.c @ 0:17cb7cdbb8be draft default tip

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Working prototype
author Ivo Smits <Ivo@UCIS.nl>
date Fri, 07 Feb 2014 23:28:39 +0100
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1 /* Copyright 2014 Ivo Smits <Ivo@UCIS.nl>. All rights reserved.
2 Redistribution and use in source and binary forms, with or without modification, are
3 permitted provided that the following conditions are met:
4
5 1. Redistributions of source code must retain the above copyright notice, this list of
6 conditions and the following disclaimer.
7
8 2. Redistributions in binary form must reproduce the above copyright notice, this list
9 of conditions and the following disclaimer in the documentation and/or other materials
10 provided with the distribution.
11
12 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
13 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
14 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR
15 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
16 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
17 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
18 ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
19 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
20 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
21
22 The views and conclusions contained in the software and documentation are those of the
23 authors and should not be interpreted as representing official policies, either expressed
24 or implied, of Ivo Smits.*/
25
26 #include <stdio.h>
27 #include <stdbool.h>
28 #include <stdlib.h>
29 #include <unistd.h>
30 #include <sys/types.h>
31 #include <sys/uio.h>
32 #include <string.h>
33 #include <fcntl.h>
34 #include <sys/ioctl.h>
35 #include <net/if.h>
36 #ifdef linux
37 #include <linux/if_tun.h>
38 #include <linux/if_ether.h>
39 #else
40 #define ETH_FRAME_LEN 1514
41 #include <net/if_tun.h>
42 #ifdef SOLARIS
43 #include <sys/stropts.h>
44 #include <sys/sockio.h>
45 #endif
46 #endif
47 #include "include.h"
48
49 static unsigned char readbuffer[2000];
50
51 bool tunnel_write_data(tunnel_context* context, unsigned char* buffer, int len) {
52 if (context->fake_pi) {
53 if (len == 0) return true;
54 int ipver = (*buffer >> 4) & 0xf;
55 int pihdr = 0;
56 #if defined linux
57 if (ipver == 4) pihdr = 0x0000 | (0x0008 << 16); //little endian: flags and protocol are swapped
58 else if (ipver == 6) pihdr = 0x0000 | (0xdd86 << 16);
59 #else
60 if (ipver == 4) pihdr = htonl(AF_INET);
61 else if (ipver == 6) pihdr = htonl(AF_INET6);
62 #endif
63 struct iovec iov[2];
64 iov[0].iov_base = &pihdr;
65 iov[0].iov_len = sizeof(pihdr);
66 iov[1].iov_base = buffer;
67 iov[1].iov_len = len;
68 writev(context->fd, iov, 2);
69 } else {
70 write(context->fd, buffer, len);
71 }
72 return true;
73 }
74
75 bool tunnel_read(tunnel_context* context) {
76 int len = read(context->fd, readbuffer, sizeof(readbuffer));
77 if (len < 0) return errorexitp("read failure on tap device");
78 if (!context->connection) return true;
79 if (context->fake_pi) {
80 if (len < 4) return errorexit("short packet received from tap device");
81 connection_write_data(context->connection, readbuffer + 4, len - 4);
82 } else {
83 connection_write_data(context->connection, readbuffer, len);
84 }
85 return true;
86 }
87
88 bool tunnel_init(tunnel_context* context) {
89 memset(context, 0, sizeof(tunnel_context));
90 char* envval;
91 fprintf(stderr, "Initializing tun/tap device...\n");
92 int ttfd; //Tap device file descriptor
93 int tunmode = 0;
94 if ((envval = getconf("TUN_MODE"))) tunmode = atoi(envval);
95 #if defined(__linux__)
96 struct ifreq ifr; //required for tun/tap setup
97 memset(&ifr, 0, sizeof(ifr));
98 if ((ttfd = open("/dev/net/tun", O_RDWR)) < 0) return errorexitp("Could not open tun/tap device file");
99 if ((envval = getconf("INTERFACE"))) strcpy(ifr.ifr_name, envval);
100 ifr.ifr_flags = tunmode ? IFF_TUN : IFF_TAP;
101 ifr.ifr_flags |= IFF_NO_PI;
102 if (ioctl(ttfd, TUNSETIFF, (void *)&ifr) < 0) return errorexitp("TUNSETIFF ioctl failed");
103 #elif defined SOLARIS
104 int ip_fd = -1, if_fd = -1, ppa = 0;
105 if ((ttfd = open("/dev/tun", O_RDWR)) < 0) return errorexitp("Could not open tun device file");
106 if ((ip_fd = open("/dev/ip", O_RDWR, 0)) < 0) return errorexitp("Could not open /dev/ip");
107 if ((envval = getconf("INTERFACE"))) {
108 while (*envval && !isdigit((int)*envval)) envval++;
109 ppa = atoi(envval);
110 }
111 if ((ppa = ioctl(ttfd, TUNNEWPPA, ppa)) < 0) return errorexitp("Could not assign new PPA");
112 if ((if_fd = open("/dev/tun", O_RDWR, 0)) < 0) return errorexitp("Could not open tun device file again");
113 if (ioctl(if_fd, I_PUSH, "ip") < 0) return errorexitp("Could not push IP module");
114 if (ioctl(if_fd, IF_UNITSEL, (char *)&ppa) < 0) return errorexitp("Could not set PPA");
115 if (ioctl(ip_fd, I_LINK, if_fd) < 0) return errorexitp("Could not link TUN device to IP");
116 #else
117 if (!(envval = getconf("INTERFACE"))) envval = "/dev/tun0";
118 if ((ttfd = open(envval, O_RDWR)) < 0) return errorexitp("Could not open tun device file");
119 if (tunmode) {
120 int i = IFF_POINTOPOINT | IFF_MULTICAST;
121 ioctl(ttfd, TUNSIFMODE, &i);
122 #if defined(__OpenBSD__)
123 context->fake_pi = true;
124 #else
125 i = 1;
126 ioctl(ttfd, TUNSIFHEAD, &i);
127 #endif
128 }
129 #endif
130 if ((envval = getconf("TUN_UP_SCRIPT"))) system(envval);
131 context->fd = ttfd;
132 return true;
133 }
134