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source: vbox/trunk/src/VBox/NetworkServices/NAT/proxy_rtadvd.c@ 49016

Last change on this file since 49016 was 49016, checked in by vboxsync, 11 years ago

Change vestigial names proxytest.* to proxy.*
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id Revision
File size: 10.5 KB
Line 
1/* -*- indent-tabs-mode: nil; -*- */
2#include "winutils.h"
3
4#include "proxy.h"
5
6#include "lwip/opt.h"
7#include "lwip/sys.h"
8#include "lwip/stats.h"
9#include "lwip/timers.h"
10
11#include "lwip/inet_chksum.h"
12#include "lwip/icmp6.h"
13#include "lwip/nd6.h"
14
15#include "lwip/raw.h"
16
17#include <string.h>
18
19
20static void proxy_rtadvd_timer(void *);
21static void proxy_rtadvd_send_multicast(struct netif *);
22static void proxy_rtadvd_fill_payload(struct netif *, int);
23
24static u8_t rtadvd_recv(void *, struct raw_pcb *, struct pbuf *, ip6_addr_t *);
25
26
27/* ff02::1 - link-local all nodes multicast address */
28static ip6_addr_t allnodes_linklocal = {
29 { PP_HTONL(0xff020000UL), 0, 0, PP_HTONL(0x00000001UL) }
30};
31
32
33/*
34 * Unsolicited Router Advertisement payload.
35 *
36 * NB: Since ICMP checksum covers pseudo-header with destination
37 * address (link-local allnodes multicast in this case) this payload
38 * cannot be used for solicited replies to unicast addresses.
39 */
40static unsigned int unsolicited_ra_payload_length;
41static u8_t unsolicited_ra_payload[
42 sizeof(struct ra_header)
43 /* reserves enough space for NETIF_MAX_HWADDR_LEN */
44 + sizeof(struct lladdr_option)
45 /* we only announce one prefix */
46 + sizeof(struct prefix_option) * 1
47];
48
49
50static int ndefaults = 0;
51
52static struct raw_pcb *rtadvd_pcb;
53
54
55void
56proxy_rtadvd_start(struct netif *proxy_netif)
57{
58
59 ndefaults = rtmon_get_defaults();
60 if (ndefaults < 0) {
61 DPRINTF0(("rtadvd: failed to read IPv6 routing table, aborting\n"));
62 return;
63 }
64
65 proxy_rtadvd_fill_payload(proxy_netif, ndefaults > 0);
66
67 rtadvd_pcb = raw_new_ip6(IP6_NEXTH_ICMP6);
68 if (rtadvd_pcb == NULL) {
69 DPRINTF0(("rtadvd: failed to allocate pcb, aborting\n"));
70 return;
71 }
72
73 /*
74 * We cannot use raw_bind_ip6() since raw_input() doesn't grok
75 * multicasts. We are going to use ip6_output_if() directly.
76 */
77 raw_recv_ip6(rtadvd_pcb, rtadvd_recv, proxy_netif);
78
79 sys_timeout(3 * 1000, proxy_rtadvd_timer, proxy_netif);
80}
81
82
83static int quick_ras = 2;
84
85static void
86proxy_rtadvd_timer(void *arg)
87{
88 struct netif *proxy_netif = (struct netif *)arg;
89 int newdefs;
90 u32_t delay;
91
92 newdefs = rtmon_get_defaults();
93 if (newdefs != ndefaults && newdefs != -1) {
94 ndefaults = newdefs;
95 proxy_rtadvd_fill_payload(proxy_netif, ndefaults > 0);
96 }
97
98 proxy_rtadvd_send_multicast(proxy_netif);
99
100 if (quick_ras > 0) {
101 --quick_ras;
102 delay = 16 * 1000;
103 }
104 else {
105 delay = 600 * 1000;
106 }
107
108 sys_timeout(delay, proxy_rtadvd_timer, proxy_netif);
109}
110
111
112/*
113 * This should be folded into icmp6/nd6 input, but I don't want to
114 * solve this in general, making it configurable, etc.
115 *
116 * Cf. RFC 4861:
117 * 6.1.1. Validation of Router Solicitation Messages
118 */
119static u8_t
120rtadvd_recv(void *arg, struct raw_pcb *pcb, struct pbuf *p, ip6_addr_t *addr)
121{
122 enum raw_recv_status { RAW_RECV_CONTINUE = 0, RAW_RECV_CONSUMED = 1 };
123
124 struct netif *proxy_netif = (struct netif *)arg;
125 struct ip6_hdr *ip6_hdr;
126 struct icmp6_hdr *icmp6_hdr;
127 struct lladdr_option *lladdr_opt;
128 void *option;
129 u8_t opttype, optlen8;
130
131 LWIP_UNUSED_ARG(pcb);
132 LWIP_UNUSED_ARG(addr);
133
134 /* save a pointer to IP6 header and skip to ICMP6 payload */
135 ip6_hdr = (struct ip6_hdr *)p->payload;
136 pbuf_header(p, -ip_current_header_tot_len());
137
138 if (p->len < sizeof(struct icmp6_hdr)) {
139 ICMP6_STATS_INC(icmp6.lenerr);
140 goto drop;
141 }
142
143 if (ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->tot_len,
144 ip6_current_src_addr(),
145 ip6_current_dest_addr()) != 0)
146 {
147 ICMP6_STATS_INC(icmp6.chkerr);
148 goto drop;
149 }
150
151 icmp6_hdr = (struct icmp6_hdr *)p->payload;
152 if (icmp6_hdr->type != ICMP6_TYPE_RS) {
153 pbuf_header(p, ip_current_header_tot_len()); /* restore payload ptr */
154 return RAW_RECV_CONTINUE; /* not interested */
155 }
156
157 /* only now that we know it's ICMP6_TYPE_RS we can check IP6 hop limit */
158 if (IP6H_HOPLIM(ip6_hdr) != 255) {
159 ICMP6_STATS_INC(icmp6.proterr);
160 goto drop;
161 }
162
163 /* future, backward-incompatible changes may use different Code values. */
164 if (icmp6_hdr->code != 0) {
165 ICMP6_STATS_INC(icmp6.proterr);
166 goto drop;
167 }
168
169 /* skip past rs_header, nothing interesting in it */
170 if (p->len < sizeof(struct rs_header)) {
171 ICMP6_STATS_INC(icmp6.lenerr);
172 goto drop;
173 }
174 pbuf_header(p, -(s16_t)sizeof(struct rs_header));
175
176 lladdr_opt = NULL;
177 while (p->len > 0) {
178 unsigned int optlen;
179
180 if (p->len < 8) {
181 ICMP6_STATS_INC(icmp6.lenerr);
182 goto drop;
183 }
184
185 option = p->payload;
186 opttype = ((u8_t *)option)[0];
187 optlen8 = ((u8_t *)option)[1]; /* in units of 8 octets */
188
189 if (optlen8 == 0) {
190 ICMP6_STATS_INC(icmp6.proterr);
191 goto drop;
192 }
193
194 optlen = (unsigned int)optlen8 << 3;
195 if (p->len < optlen) {
196 ICMP6_STATS_INC(icmp6.lenerr);
197 goto drop;
198 }
199
200 if (opttype == ND6_OPTION_TYPE_SOURCE_LLADDR) {
201 if (lladdr_opt != NULL) { /* duplicate */
202 ICMP6_STATS_INC(icmp6.proterr);
203 goto drop;
204 }
205 lladdr_opt = (struct lladdr_option *)option;
206 }
207
208 pbuf_header(p, -optlen);
209 }
210
211 if (ip6_addr_isany(ip6_current_src_addr())) {
212 if (lladdr_opt != NULL) {
213 ICMP6_STATS_INC(icmp6.proterr);
214 goto drop;
215 }
216
217 /* reply with multicast RA */
218 }
219 else {
220 /*
221 * XXX: Router is supposed to update its Neighbor Cache (6.2.6),
222 * but it's hidden inside nd6.c.
223 */
224
225 /* may reply with either unicast or multicast RA */
226 }
227 /* we just always reply with multicast RA */
228
229 pbuf_free(p); /* NB: this invalidates lladdr_option */
230
231 sys_untimeout(proxy_rtadvd_timer, proxy_netif);
232 proxy_rtadvd_timer(proxy_netif); /* sends and re-arms */
233
234 return RAW_RECV_CONSUMED;
235
236 drop:
237 pbuf_free(p);
238 ICMP6_STATS_INC(icmp6.drop);
239 return RAW_RECV_CONSUMED;
240}
241
242
243static void
244proxy_rtadvd_send_multicast(struct netif *proxy_netif)
245{
246 struct pbuf *ph, *pp;
247 err_t error;
248
249 ph = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
250 if (ph == NULL) {
251 DPRINTF0(("%s: failed to allocate RA header pbuf", __func__));
252 return;
253 }
254
255 pp = pbuf_alloc(PBUF_RAW, unsolicited_ra_payload_length, PBUF_ROM);
256 if (pp == NULL) {
257 DPRINTF0(("%s: failed to allocate RA payload pbuf", __func__));
258 pbuf_free(ph);
259 return;
260 }
261 pp->payload = unsolicited_ra_payload;
262 pbuf_chain(ph, pp);
263
264 error = ip6_output_if(ph,
265 netif_ip6_addr(proxy_netif, 0), /* src: link-local */
266 &allnodes_linklocal, /* dst */
267 255, /* hop limit */
268 0, /* traffic class */
269 IP6_NEXTH_ICMP6,
270 proxy_netif);
271 if (error != ERR_OK) {
272 DPRINTF0(("%s: failed to send RA (err=%d)", __func__, error));
273 }
274
275 pbuf_free(pp);
276 pbuf_free(ph);
277}
278
279
280/*
281 * XXX: TODO: Only ra_header::router_lifetime (and hence
282 * ra_header::chksum) need to be changed, so we can precompute it once
283 * and then only update these two fields.
284 */
285static void
286proxy_rtadvd_fill_payload(struct netif *proxy_netif, int is_default)
287{
288 struct pbuf *p;
289 struct ra_header *ra_hdr;
290 struct lladdr_option *lladdr_opt;
291 struct prefix_option *pfx_opt;
292 unsigned int lladdr_optlen;
293
294 LWIP_ASSERT("netif hwaddr too long",
295 proxy_netif->hwaddr_len <= NETIF_MAX_HWADDR_LEN);
296
297 /* type + length + ll addr + round up to 8 octets */
298 lladdr_optlen = (2 + proxy_netif->hwaddr_len + 7) & ~0x7;
299
300 /* actual payload length */
301 unsolicited_ra_payload_length =
302 sizeof(struct ra_header)
303 + lladdr_optlen
304 + sizeof(struct prefix_option) * 1;
305
306 /* Set fields. */
307 ra_hdr = (struct ra_header *)unsolicited_ra_payload;
308 lladdr_opt = (struct lladdr_option *)((u8_t *)ra_hdr + sizeof(struct ra_header));
309 pfx_opt = (struct prefix_option *)((u8_t *)lladdr_opt + lladdr_optlen);
310
311 memset(unsolicited_ra_payload, 0, sizeof(unsolicited_ra_payload));
312
313 ra_hdr->type = ICMP6_TYPE_RA;
314
315#if 0
316 /*
317 * "M" flag. Tell guests to use stateful DHCP6. Disabled here
318 * since we don't provide stateful server.
319 */
320 ra_hdr->flags |= ND6_RA_FLAG_MANAGED_ADDR_CONFIG;
321#endif
322 /*
323 * XXX: TODO: Disable "O" flag for now to match disabled stateless
324 * server. We don't yet get IPv6 nameserver addresses from
325 * HostDnsService, so we have nothing to say, don't tell guests to
326 * come asking.
327 */
328#if 0
329 /*
330 * "O" flag. Tell guests to use DHCP6 for DNS and the like. This
331 * is served by simple stateless server (RFC 3736).
332 *
333 * XXX: "STATEFUL" in the flag name was probably a bug in RFC2461.
334 * It's present in the text, but not in the router configuration
335 * variable name. It's dropped in the text in RFC4861.
336 */
337 ra_hdr->flags |= ND6_RA_FLAG_OTHER_STATEFUL_CONFIG;
338#endif
339
340 if (is_default) {
341 ra_hdr->router_lifetime = PP_HTONS(1200); /* seconds */
342 }
343 else {
344 ra_hdr->router_lifetime = 0;
345 }
346
347 lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR;
348 lladdr_opt->length = lladdr_optlen >> 3; /* in units of 8 octets */
349 memcpy(lladdr_opt->addr, proxy_netif->hwaddr, proxy_netif->hwaddr_len);
350
351 pfx_opt->type = ND6_OPTION_TYPE_PREFIX_INFO;
352 pfx_opt->length = 4;
353 pfx_opt->prefix_length = 64;
354 pfx_opt->flags = ND6_PREFIX_FLAG_ON_LINK
355 | ND6_PREFIX_FLAG_AUTONOMOUS;
356 pfx_opt->valid_lifetime = ~0U; /* infinite */
357 pfx_opt->preferred_lifetime = ~0U; /* infinite */
358 pfx_opt->prefix.addr[0] = netif_ip6_addr(proxy_netif, 1)->addr[0];
359 pfx_opt->prefix.addr[1] = netif_ip6_addr(proxy_netif, 1)->addr[1];
360
361
362 /* we need a temp pbuf to calculate the checksum */
363 p = pbuf_alloc(PBUF_IP, unsolicited_ra_payload_length, PBUF_ROM);
364 if (p == NULL) {
365 DPRINTF0(("rtadvd: failed to allocate RA pbuf\n"));
366 return;
367 }
368 p->payload = unsolicited_ra_payload;
369
370 ra_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len,
371 /* src addr: netif's link-local */
372 netif_ip6_addr(proxy_netif, 0),
373 /* dst addr */
374 &allnodes_linklocal);
375 pbuf_free(p);
376}
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