File: routing.c

package info (click to toggle)
pptp-linux 1.10.0-2
  • links: PTS
  • area: main
  • in suites: forky, sid, trixie
  • size: 640 kB
  • sloc: ansic: 3,689; makefile: 142; perl: 117
file content (195 lines) | stat: -rw-r--r-- 5,433 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
/*
    routing.c, manipulating routing table for PPTP Client
    Copyright (C) 2006  Free Software Foundation

    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 2 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, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    02110-1301, USA

*/

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include "routing.h"
#include "config.h"

#if defined (__SVR4) && defined (__sun) /* Solaris */
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <errno.h>
#include "util.h"
/* PF_ROUTE socket*/
int rts; 
/* Destination and gateway addresses */
struct sockaddr_in rdst, rgw;
/* Request sequence */
int rseq;
int dorouting;
#else /* Solaris */
/* route to the server */
char *route;
#endif /* Solaris */

/*

Design discussion.

The primary task of this module is to add a host route to the PPTP
server so that the kernel continues to deliver PPTP control and data
connection packets to the server despite the new PPP interface that is
created.  The flag --nohostroute is to disable this.

A secondary task may be to implement all-to-tunnel routing if the
appropriate flag is specified on the command line.  The flag
--route-all is to implement this (not yet implemented).

Caveat.

It is not possible from the "ip route" command to determine if a host
route already exists, so it isn't practical to put the routing table
back exactly as it was.

We have a choice of either leaving our route lying around, or
destroying a route that the user had pre-arranged.  Both are
unfortunate.  The flag --remove-host-route is to remove the route
regardless (not yet implemented).

*/

void routing_init(char *ip) {
#if defined (__SVR4) && defined (__sun) /* Solaris */
  rdst.sin_family = AF_INET;
  if ( ! inet_pton(AF_INET, ip, &rdst.sin_addr) ) {
    log("Cannot convert address: %s", strerror(errno));
    return;
  }

  if ( (rts = socket(PF_ROUTE, SOCK_RAW, AF_INET )) < 0 ) {
    log("Cannot open routing socket: %s", strerror(errno));
    return;
  }

  struct rt_msg rtm = {
    .hdr.rtm_msglen = sizeof(struct rt_msg),
    .hdr.rtm_version = RTM_VERSION,
    .hdr.rtm_type = RTM_GET,
    .hdr.rtm_addrs = RTA_DST,
    .hdr.rtm_pid = getpid(),
    .hdr.rtm_seq = ++rseq,
    .addrs[RTAX_DST] = rdst
  };

  if ( write(rts, &rtm, rtm.hdr.rtm_msglen) != rtm.hdr.rtm_msglen ) {
    log("Error writing to routing socket: %s", strerror(errno));
    close(rts);
    return;
  }

  while ( read(rts, &rtm, sizeof(struct rt_msg)) > 0 )
    if ( rtm.hdr.rtm_pid == getpid() && rtm.hdr.rtm_seq == rseq) {
      /* Check if host route already present */
      if ( ( rtm.hdr.rtm_flags & RTF_HOST ) != RTF_HOST ) {
        rgw = rtm.addrs[RTAX_GATEWAY];
        dorouting = 1;
      }
      break;
    }
#endif /* Solaris */ 
#if defined(__linux)
  char buf[256];
  char tbuf[256];
  const char *uid;
  FILE *p;

  snprintf(buf, 255, "%s route get %s", IP_BINARY, ip);
  p = popen(buf, "r");
  fgets(buf, 255, p);
  /* TODO: check for failure of fgets */
  uid = strstr(buf, " uid");
  if (uid) {
    snprintf(tbuf, uid - buf + 1, "%s", buf);
    route = strdup(tbuf);
  } else {
    route = strdup(buf);
  }
  pclose(p);
  /* TODO: check for failure of command */
#endif /* __linux__ */
}

void routing_start(void) {
#if defined (__SVR4) && defined (__sun) /* Solaris */
  if ( ! dorouting )
     return;

  struct rt_msg rtm = {
    .hdr.rtm_msglen = sizeof(struct rt_msg),
    .hdr.rtm_version = RTM_VERSION,
    .hdr.rtm_type = RTM_ADD,
    .hdr.rtm_flags = RTF_HOST | RTF_GATEWAY | RTF_STATIC,
    .hdr.rtm_addrs = RTA_DST | RTA_GATEWAY,
    .hdr.rtm_pid = getpid(),
    .hdr.rtm_seq = ++rseq,
    .addrs[RTAX_DST] = rdst,
    .addrs[RTAX_GATEWAY] = rgw
  };

  if ( write(rts, &rtm, rtm.hdr.rtm_msglen) != rtm.hdr.rtm_msglen ) {
    log("Error adding route: %s", strerror(errno));
  }
#endif
#if defined(__linux__)
  char buf[256];
  FILE *p;

  snprintf(buf, 255, "%s route replace %s", IP_BINARY, route);
  p = popen(buf, "r");
  pclose(p);
#endif /* __linux__ */
}

void routing_end(void) {
#if defined (__SVR4) && defined (__sun) /* Solaris */
  if ( ! dorouting)
    return;

  struct rt_msg rtm = {
    .hdr.rtm_msglen = sizeof(struct rt_msg),
    .hdr.rtm_version = RTM_VERSION,
    .hdr.rtm_type = RTM_DELETE,
    .hdr.rtm_flags = RTF_HOST | RTF_GATEWAY | RTF_STATIC,
    .hdr.rtm_addrs = RTA_DST | RTA_GATEWAY,
    .hdr.rtm_pid = getpid(),
    .hdr.rtm_seq = ++rseq,
    .addrs[RTAX_DST] = rdst,
    .addrs[RTAX_GATEWAY] = rgw
  };

  if ( write(rts, &rtm, rtm.hdr.rtm_msglen) != rtm.hdr.rtm_msglen ) {
    log("Error deleting route: %s", strerror(errno));
  }
#endif /* Solaris */
#if defined(__linux__)
  char buf[256];
  FILE *p;

  snprintf(buf, 255, "%s route delete %s", IP_BINARY, route);
  p = popen(buf, "r");
  pclose(p);
#endif /* __linux__ */
}