more DoS prevention: add packet_limit option to apply a hard limit to downstream...
[l2tpns.git] / garden.c
1 #include <string.h>
2 #include <malloc.h>
3 #include <stdlib.h>
4 #include <sys/wait.h>
5 #include <sys/types.h>
6 #include "l2tpns.h"
7 #include "plugin.h"
8 #include "control.h"
9
10 /* walled garden */
11
12 char const *cvs_id = "$Id: garden.c,v 1.20 2004/12/16 08:49:53 bodea Exp $";
13
14 int plugin_api_version = PLUGIN_API_VERSION;
15 static struct pluginfuncs *p = 0;
16
17 static int iam_master = 0; // We're all slaves! Slaves I tell you!
18
19 char *up_commands[] = {
20 "iptables -t nat -N garden >/dev/null 2>&1", // Create a chain that all gardened users will go through
21 "iptables -t nat -F garden",
22 ". " PLUGINCONF "/build-garden", // Populate with site-specific DNAT rules
23 "iptables -t nat -N garden_users >/dev/null 2>&1", // Empty chain, users added/removed by garden_session
24 "iptables -t nat -F garden_users",
25 "iptables -t nat -A PREROUTING -j garden_users", // DNAT any users on the garden_users chain
26 "sysctl -w net.ipv4.ip_conntrack_max=512000 >/dev/null", // lots of entries
27 NULL,
28 };
29
30 char *down_commands[] = {
31 "iptables -t nat -F PREROUTING",
32 "iptables -t nat -F garden_users",
33 "iptables -t nat -X garden_users",
34 "iptables -t nat -F garden",
35 "iptables -t nat -X garden",
36 "rmmod iptable_nat", // Should also remove ip_conntrack, but
37 // doing so can take hours... literally.
38 // If a master is re-started as a slave,
39 // either rmmod manually, or reboot.
40 NULL,
41 };
42
43 #define F_UNGARDEN 0
44 #define F_GARDEN 1
45 #define F_CLEANUP 2
46
47 int garden_session(sessiont *s, int flag);
48
49 int plugin_post_auth(struct param_post_auth *data)
50 {
51 // Ignore if user authentication was successful
52 if (data->auth_allowed) return PLUGIN_RET_OK;
53
54 p->log(3, p->get_id_by_session(data->s), data->s->tunnel, "Walled Garden allowing login\n");
55 data->auth_allowed = 1;
56 data->s->walled_garden = 1;
57 return PLUGIN_RET_OK;
58 }
59
60 int plugin_new_session(struct param_new_session *data)
61 {
62 if (!iam_master)
63 return PLUGIN_RET_OK; // Slaves don't do walled garden processing.
64
65 if (data->s->walled_garden)
66 garden_session(data->s, F_GARDEN);
67
68 return PLUGIN_RET_OK;
69 }
70
71 int plugin_kill_session(struct param_new_session *data)
72 {
73 if (!iam_master)
74 return PLUGIN_RET_OK; // Slaves don't do walled garden processing.
75
76 if (data->s->walled_garden)
77 garden_session(data->s, F_CLEANUP);
78
79 return PLUGIN_RET_OK;
80 }
81
82 char *plugin_control_help[] = {
83 " garden USER|SID Put user into the walled garden",
84 " ungarden SID Release session from garden",
85 0
86 };
87
88 int plugin_control(struct param_control *data)
89 {
90 sessionidt session;
91 sessiont *s = 0;
92 int flag;
93 char *end;
94
95 if (data->argc < 1)
96 return PLUGIN_RET_OK;
97
98 if (strcmp(data->argv[0], "garden") && strcmp(data->argv[0], "ungarden"))
99 return PLUGIN_RET_OK; // not for us
100
101 if (!iam_master)
102 return PLUGIN_RET_NOTMASTER;
103
104 flag = data->argv[0][0] == 'g' ? F_GARDEN : F_UNGARDEN;
105
106 if (data->argc != 2)
107 {
108 data->response = NSCTL_RES_ERR;
109 data->additional = "one argument required: username or session id";
110 return PLUGIN_RET_STOP;
111 }
112
113 if (!(session = strtol(data->argv[1], &end, 10)) || *end)
114 {
115 if (flag)
116 session = p->get_session_by_username(data->argv[1]);
117 else
118 session = 0; // can't ungarden by username
119 }
120
121 if (session)
122 s = p->get_session_by_id(session);
123
124 if (!s || !s->ip)
125 {
126 data->response = NSCTL_RES_ERR;
127 data->additional = "session not found";
128 return PLUGIN_RET_STOP;
129 }
130
131 if (s->walled_garden == flag)
132 {
133 data->response = NSCTL_RES_ERR;
134 data->additional = flag ? "already in walled garden" : "not in walled garden";
135 return PLUGIN_RET_STOP;
136 }
137
138 garden_session(s, flag);
139 p->session_changed(session);
140
141 data->response = NSCTL_RES_OK;
142 data->additional = 0;
143
144 return PLUGIN_RET_STOP;
145 }
146
147 int plugin_become_master(void)
148 {
149 int i;
150 iam_master = 1; // We just became the master. Wow!
151
152 for (i = 0; up_commands[i] && *up_commands[i]; i++)
153 {
154 p->log(3, 0, 0, "Running %s\n", up_commands[i]);
155 system(up_commands[i]);
156 }
157
158 return PLUGIN_RET_OK;
159 }
160
161 // Called for each active session after becoming master
162 int plugin_new_session_master(sessiont *s)
163 {
164 if (s->walled_garden)
165 garden_session(s, F_GARDEN);
166
167 return PLUGIN_RET_OK;
168 }
169
170 int garden_session(sessiont *s, int flag)
171 {
172 char cmd[2048];
173 sessionidt sess;
174
175 if (!s) return 0;
176 if (!s->opened) return 0;
177
178 sess = p->get_id_by_session(s);
179 if (flag == F_GARDEN)
180 {
181 p->log(2, sess, s->tunnel, "Garden user %s (%s)\n", s->user, p->fmtaddr(htonl(s->ip), 0));
182 snprintf(cmd, sizeof(cmd), "iptables -t nat -A garden_users -s %s -j garden", p->fmtaddr(htonl(s->ip), 0));
183 p->log(3, sess, s->tunnel, "%s\n", cmd);
184 system(cmd);
185 s->walled_garden = 1;
186 }
187 else
188 {
189 sessionidt other;
190 int count = 40;
191
192 // Normal User
193 p->log(2, sess, s->tunnel, "Un-Garden user %s (%s)\n", s->user, p->fmtaddr(htonl(s->ip), 0));
194 // Kick off any duplicate usernames
195 // but make sure not to kick off ourself
196 if (s->ip && !s->die && (other = p->get_session_by_username(s->user)) && s != p->get_session_by_id(other)) {
197 p->sessionkill(other, "Duplicate session when user released from walled garden");
198 }
199 /* Clean up counters */
200 s->cin = s->cout = 0;
201 s->pin = s->pout = 0;
202
203 snprintf(cmd, sizeof(cmd), "iptables -t nat -D garden_users -s %s -j garden", p->fmtaddr(htonl(s->ip), 0));
204 p->log(3, sess, s->tunnel, "%s\n", cmd);
205 while (--count)
206 {
207 int status = system(cmd);
208 if (WEXITSTATUS(status) != 0) break;
209 }
210
211 s->walled_garden = 0;
212
213 if (flag != F_CLEANUP)
214 {
215 /* OK, we're up! */
216 uint16_t r = p->radiusnew(p->get_id_by_session(s));
217 p->radiussend(r, RADIUSSTART);
218 }
219 }
220
221 return 1;
222 }
223
224 int plugin_init(struct pluginfuncs *funcs)
225 {
226 FILE *tables;
227 int found_nat = 0;
228
229 if (!funcs)
230 return 0;
231
232 p = funcs;
233
234 if ((tables = fopen("/proc/net/ip_tables_names", "r")))
235 {
236 char buf[1024];
237 while (fgets(buf, sizeof(buf), tables) && !found_nat)
238 found_nat = !strcmp(buf, "nat\n");
239
240 fclose(tables);
241 }
242
243 /* master killed/crashed? */
244 if (found_nat)
245 {
246 int i;
247 for (i = 0; down_commands[i] && *down_commands[i]; i++)
248 {
249 p->log(3, 0, 0, "Running %s\n", down_commands[i]);
250 system(down_commands[i]);
251 }
252 }
253
254 return 1;
255 }
256
257 void plugin_done()
258 {
259 int i;
260
261 if (!iam_master) // Never became master. nothing to do.
262 return;
263
264 for (i = 0; down_commands[i] && *down_commands[i]; i++)
265 {
266 p->log(3, 0, 0, "Running %s\n", down_commands[i]);
267 system(down_commands[i]);
268 }
269 }
270