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25#define KMSG_COMPONENT "IPVS"
26#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
27
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/kernel.h>
31#include <linux/skbuff.h>
32#include <linux/in.h>
33#include <linux/ip.h>
34#include <linux/netfilter.h>
35#include <net/protocol.h>
36#include <net/tcp.h>
37#include <asm/unaligned.h>
38
39#include <net/ip_vs.h>
40
41
42#define SERVER_STRING "227 Entering Passive Mode ("
43#define CLIENT_STRING "PORT "
44
45
46
47
48
49
50static unsigned short ports[IP_VS_APP_MAX_PORTS] = {21, 0};
51module_param_array(ports, ushort, NULL, 0);
52MODULE_PARM_DESC(ports, "Ports to monitor for FTP control commands");
53
54
55
56static int ip_vs_ftp_pasv;
57
58
59static int
60ip_vs_ftp_init_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
61{
62 return 0;
63}
64
65
66static int
67ip_vs_ftp_done_conn(struct ip_vs_app *app, struct ip_vs_conn *cp)
68{
69 return 0;
70}
71
72
73
74
75
76
77
78static int ip_vs_ftp_get_addrport(char *data, char *data_limit,
79 const char *pattern, size_t plen, char term,
80 __be32 *addr, __be16 *port,
81 char **start, char **end)
82{
83 unsigned char p[6];
84 int i = 0;
85
86 if (data_limit - data < plen) {
87
88 if (strnicmp(data, pattern, data_limit - data) == 0)
89 return -1;
90 else
91 return 0;
92 }
93
94 if (strnicmp(data, pattern, plen) != 0) {
95 return 0;
96 }
97 *start = data + plen;
98
99 for (data = *start; *data != term; data++) {
100 if (data == data_limit)
101 return -1;
102 }
103 *end = data;
104
105 memset(p, 0, sizeof(p));
106 for (data = *start; data != *end; data++) {
107 if (*data >= '0' && *data <= '9') {
108 p[i] = p[i]*10 + *data - '0';
109 } else if (*data == ',' && i < 5) {
110 i++;
111 } else {
112
113 return -1;
114 }
115 }
116
117 if (i != 5)
118 return -1;
119
120 *addr = get_unaligned((__be32 *)p);
121 *port = get_unaligned((__be16 *)(p + 4));
122 return 1;
123}
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
140 struct sk_buff *skb, int *diff)
141{
142 struct iphdr *iph;
143 struct tcphdr *th;
144 char *data, *data_limit;
145 char *start, *end;
146 union nf_inet_addr from;
147 __be16 port;
148 struct ip_vs_conn *n_cp;
149 char buf[24];
150 unsigned buf_len;
151 int ret;
152
153#ifdef CONFIG_IP_VS_IPV6
154
155
156
157 if (cp->af == AF_INET6)
158 return 1;
159#endif
160
161 *diff = 0;
162
163
164 if (cp->state != IP_VS_TCP_S_ESTABLISHED)
165 return 1;
166
167
168 if (!skb_make_writable(skb, skb->len))
169 return 0;
170
171 if (cp->app_data == &ip_vs_ftp_pasv) {
172 iph = ip_hdr(skb);
173 th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
174 data = (char *)th + (th->doff << 2);
175 data_limit = skb_tail_pointer(skb);
176
177 if (ip_vs_ftp_get_addrport(data, data_limit,
178 SERVER_STRING,
179 sizeof(SERVER_STRING)-1, ')',
180 &from.ip, &port,
181 &start, &end) != 1)
182 return 1;
183
184 IP_VS_DBG(7, "PASV response (%pI4:%d) -> %pI4:%d detected\n",
185 &from.ip, ntohs(port), &cp->caddr.ip, 0);
186
187
188
189
190 n_cp = ip_vs_conn_out_get(AF_INET, iph->protocol, &from, port,
191 &cp->caddr, 0);
192 if (!n_cp) {
193 n_cp = ip_vs_conn_new(AF_INET, IPPROTO_TCP,
194 &cp->caddr, 0,
195 &cp->vaddr, port,
196 &from, port,
197 IP_VS_CONN_F_NO_CPORT,
198 cp->dest);
199 if (!n_cp)
200 return 0;
201
202
203 ip_vs_control_add(n_cp, cp);
204 }
205
206
207
208
209 from.ip = n_cp->vaddr.ip;
210 port = n_cp->vport;
211 sprintf(buf, "%d,%d,%d,%d,%d,%d", NIPQUAD(from.ip),
212 (ntohs(port)>>8)&255, ntohs(port)&255);
213 buf_len = strlen(buf);
214
215
216
217
218 *diff = buf_len - (end-start);
219
220 if (*diff == 0) {
221
222 memcpy(start, buf, buf_len);
223 ret = 1;
224 } else {
225 ret = !ip_vs_skb_replace(skb, GFP_ATOMIC, start,
226 end-start, buf, buf_len);
227 }
228
229 cp->app_data = NULL;
230 ip_vs_tcp_conn_listen(n_cp);
231 ip_vs_conn_put(n_cp);
232 return ret;
233 }
234 return 1;
235}
236
237
238
239
240
241
242
243
244
245
246
247
248
249static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
250 struct sk_buff *skb, int *diff)
251{
252 struct iphdr *iph;
253 struct tcphdr *th;
254 char *data, *data_start, *data_limit;
255 char *start, *end;
256 union nf_inet_addr to;
257 __be16 port;
258 struct ip_vs_conn *n_cp;
259
260#ifdef CONFIG_IP_VS_IPV6
261
262
263
264 if (cp->af == AF_INET6)
265 return 1;
266#endif
267
268
269 *diff = 0;
270
271
272 if (cp->state != IP_VS_TCP_S_ESTABLISHED)
273 return 1;
274
275
276 if (!skb_make_writable(skb, skb->len))
277 return 0;
278
279
280
281
282 iph = ip_hdr(skb);
283 th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
284
285
286
287
288 data = data_start = (char *)th + (th->doff << 2);
289 data_limit = skb_tail_pointer(skb);
290
291 while (data <= data_limit - 6) {
292 if (strnicmp(data, "PASV\r\n", 6) == 0) {
293
294 IP_VS_DBG(7, "got PASV at %td of %td\n",
295 data - data_start,
296 data_limit - data_start);
297 cp->app_data = &ip_vs_ftp_pasv;
298 return 1;
299 }
300 data++;
301 }
302
303
304
305
306
307
308
309
310 if (ip_vs_ftp_get_addrport(data_start, data_limit,
311 CLIENT_STRING, sizeof(CLIENT_STRING)-1,
312 '\r', &to.ip, &port,
313 &start, &end) != 1)
314 return 1;
315
316 IP_VS_DBG(7, "PORT %pI4:%d detected\n", &to.ip, ntohs(port));
317
318
319 cp->app_data = NULL;
320
321
322
323
324 IP_VS_DBG(7, "protocol %s %pI4:%d %pI4:%d\n",
325 ip_vs_proto_name(iph->protocol),
326 &to.ip, ntohs(port), &cp->vaddr.ip, 0);
327
328 n_cp = ip_vs_conn_in_get(AF_INET, iph->protocol,
329 &to, port,
330 &cp->vaddr, htons(ntohs(cp->vport)-1));
331 if (!n_cp) {
332 n_cp = ip_vs_conn_new(AF_INET, IPPROTO_TCP,
333 &to, port,
334 &cp->vaddr, htons(ntohs(cp->vport)-1),
335 &cp->daddr, htons(ntohs(cp->dport)-1),
336 0,
337 cp->dest);
338 if (!n_cp)
339 return 0;
340
341
342 ip_vs_control_add(n_cp, cp);
343 }
344
345
346
347
348 ip_vs_tcp_conn_listen(n_cp);
349 ip_vs_conn_put(n_cp);
350
351 return 1;
352}
353
354
355static struct ip_vs_app ip_vs_ftp = {
356 .name = "ftp",
357 .type = IP_VS_APP_TYPE_FTP,
358 .protocol = IPPROTO_TCP,
359 .module = THIS_MODULE,
360 .incs_list = LIST_HEAD_INIT(ip_vs_ftp.incs_list),
361 .init_conn = ip_vs_ftp_init_conn,
362 .done_conn = ip_vs_ftp_done_conn,
363 .bind_conn = NULL,
364 .unbind_conn = NULL,
365 .pkt_out = ip_vs_ftp_out,
366 .pkt_in = ip_vs_ftp_in,
367};
368
369
370
371
372
373static int __init ip_vs_ftp_init(void)
374{
375 int i, ret;
376 struct ip_vs_app *app = &ip_vs_ftp;
377
378 ret = register_ip_vs_app(app);
379 if (ret)
380 return ret;
381
382 for (i=0; i<IP_VS_APP_MAX_PORTS; i++) {
383 if (!ports[i])
384 continue;
385 ret = register_ip_vs_app_inc(app, app->protocol, ports[i]);
386 if (ret)
387 break;
388 pr_info("%s: loaded support on port[%d] = %d\n",
389 app->name, i, ports[i]);
390 }
391
392 if (ret)
393 unregister_ip_vs_app(app);
394
395 return ret;
396}
397
398
399
400
401
402static void __exit ip_vs_ftp_exit(void)
403{
404 unregister_ip_vs_app(&ip_vs_ftp);
405}
406
407
408module_init(ip_vs_ftp_init);
409module_exit(ip_vs_ftp_exit);
410MODULE_LICENSE("GPL");
411