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source: vbox/trunk/src/VBox/NetworkServices/NAT/proxy_rtadvd.c@ 49099

Last change on this file since 49099 was 49099, checked in by vboxsync, 11 years ago

Use proxy_options::ipv6_defroute instead of rtmon_get_defaults() to
decide whether to advertise ourselves as default router.
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id Revision
File size: 10.6 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#if 0 /* XXX */
59 ndefaults = rtmon_get_defaults();
60#else
61 ndefaults = g_proxy_options->ipv6_defroute;
62#endif
63 if (ndefaults < 0) {
64 DPRINTF0(("rtadvd: failed to read IPv6 routing table, aborting\n"));
65 return;
66 }
67
68 proxy_rtadvd_fill_payload(proxy_netif, ndefaults > 0);
69
70 rtadvd_pcb = raw_new_ip6(IP6_NEXTH_ICMP6);
71 if (rtadvd_pcb == NULL) {
72 DPRINTF0(("rtadvd: failed to allocate pcb, aborting\n"));
73 return;
74 }
75
76 /*
77 * We cannot use raw_bind_ip6() since raw_input() doesn't grok
78 * multicasts. We are going to use ip6_output_if() directly.
79 */
80 raw_recv_ip6(rtadvd_pcb, rtadvd_recv, proxy_netif);
81
82 sys_timeout(3 * 1000, proxy_rtadvd_timer, proxy_netif);
83}
84
85
86static int quick_ras = 2;
87
88static void
89proxy_rtadvd_timer(void *arg)
90{
91 struct netif *proxy_netif = (struct netif *)arg;
92 int newdefs;
93 u32_t delay;
94
95#if 0 /* XXX */
96 newdefs = rtmon_get_defaults();
97#else
98 newdefs = g_proxy_options->ipv6_defroute;
99#endif
100 if (newdefs != ndefaults && newdefs != -1) {
101 ndefaults = newdefs;
102 proxy_rtadvd_fill_payload(proxy_netif, ndefaults > 0);
103 }
104
105 proxy_rtadvd_send_multicast(proxy_netif);
106
107 if (quick_ras > 0) {
108 --quick_ras;
109 delay = 16 * 1000;
110 }
111 else {
112 delay = 600 * 1000;
113 }
114
115 sys_timeout(delay, proxy_rtadvd_timer, proxy_netif);
116}
117
118
119/*
120 * This should be folded into icmp6/nd6 input, but I don't want to
121 * solve this in general, making it configurable, etc.
122 *
123 * Cf. RFC 4861:
124 * 6.1.1. Validation of Router Solicitation Messages
125 */
126static u8_t
127rtadvd_recv(void *arg, struct raw_pcb *pcb, struct pbuf *p, ip6_addr_t *addr)
128{
129 enum raw_recv_status { RAW_RECV_CONTINUE = 0, RAW_RECV_CONSUMED = 1 };
130
131 struct netif *proxy_netif = (struct netif *)arg;
132 struct ip6_hdr *ip6_hdr;
133 struct icmp6_hdr *icmp6_hdr;
134 struct lladdr_option *lladdr_opt;
135 void *option;
136 u8_t opttype, optlen8;
137
138 LWIP_UNUSED_ARG(pcb);
139 LWIP_UNUSED_ARG(addr);
140
141 /* save a pointer to IP6 header and skip to ICMP6 payload */
142 ip6_hdr = (struct ip6_hdr *)p->payload;
143 pbuf_header(p, -ip_current_header_tot_len());
144
145 if (p->len < sizeof(struct icmp6_hdr)) {
146 ICMP6_STATS_INC(icmp6.lenerr);
147 goto drop;
148 }
149
150 if (ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->tot_len,
151 ip6_current_src_addr(),
152 ip6_current_dest_addr()) != 0)
153 {
154 ICMP6_STATS_INC(icmp6.chkerr);
155 goto drop;
156 }
157
158 icmp6_hdr = (struct icmp6_hdr *)p->payload;
159 if (icmp6_hdr->type != ICMP6_TYPE_RS) {
160 pbuf_header(p, ip_current_header_tot_len()); /* restore payload ptr */
161 return RAW_RECV_CONTINUE; /* not interested */
162 }
163
164 /* only now that we know it's ICMP6_TYPE_RS we can check IP6 hop limit */
165 if (IP6H_HOPLIM(ip6_hdr) != 255) {
166 ICMP6_STATS_INC(icmp6.proterr);
167 goto drop;
168 }
169
170 /* future, backward-incompatible changes may use different Code values. */
171 if (icmp6_hdr->code != 0) {
172 ICMP6_STATS_INC(icmp6.proterr);
173 goto drop;
174 }
175
176 /* skip past rs_header, nothing interesting in it */
177 if (p->len < sizeof(struct rs_header)) {
178 ICMP6_STATS_INC(icmp6.lenerr);
179 goto drop;
180 }
181 pbuf_header(p, -(s16_t)sizeof(struct rs_header));
182
183 lladdr_opt = NULL;
184 while (p->len > 0) {
185 unsigned int optlen;
186
187 if (p->len < 8) {
188 ICMP6_STATS_INC(icmp6.lenerr);
189 goto drop;
190 }
191
192 option = p->payload;
193 opttype = ((u8_t *)option)[0];
194 optlen8 = ((u8_t *)option)[1]; /* in units of 8 octets */
195
196 if (optlen8 == 0) {
197 ICMP6_STATS_INC(icmp6.proterr);
198 goto drop;
199 }
200
201 optlen = (unsigned int)optlen8 << 3;
202 if (p->len < optlen) {
203 ICMP6_STATS_INC(icmp6.lenerr);
204 goto drop;
205 }
206
207 if (opttype == ND6_OPTION_TYPE_SOURCE_LLADDR) {
208 if (lladdr_opt != NULL) { /* duplicate */
209 ICMP6_STATS_INC(icmp6.proterr);
210 goto drop;
211 }
212 lladdr_opt = (struct lladdr_option *)option;
213 }
214
215 pbuf_header(p, -optlen);
216 }
217
218 if (ip6_addr_isany(ip6_current_src_addr())) {
219 if (lladdr_opt != NULL) {
220 ICMP6_STATS_INC(icmp6.proterr);
221 goto drop;
222 }
223
224 /* reply with multicast RA */
225 }
226 else {
227 /*
228 * XXX: Router is supposed to update its Neighbor Cache (6.2.6),
229 * but it's hidden inside nd6.c.
230 */
231
232 /* may reply with either unicast or multicast RA */
233 }
234 /* we just always reply with multicast RA */
235
236 pbuf_free(p); /* NB: this invalidates lladdr_option */
237
238 sys_untimeout(proxy_rtadvd_timer, proxy_netif);
239 proxy_rtadvd_timer(proxy_netif); /* sends and re-arms */
240
241 return RAW_RECV_CONSUMED;
242
243 drop:
244 pbuf_free(p);
245 ICMP6_STATS_INC(icmp6.drop);
246 return RAW_RECV_CONSUMED;
247}
248
249
250static void
251proxy_rtadvd_send_multicast(struct netif *proxy_netif)
252{
253 struct pbuf *ph, *pp;
254 err_t error;
255
256 ph = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
257 if (ph == NULL) {
258 DPRINTF0(("%s: failed to allocate RA header pbuf", __func__));
259 return;
260 }
261
262 pp = pbuf_alloc(PBUF_RAW, unsolicited_ra_payload_length, PBUF_ROM);
263 if (pp == NULL) {
264 DPRINTF0(("%s: failed to allocate RA payload pbuf", __func__));
265 pbuf_free(ph);
266 return;
267 }
268 pp->payload = unsolicited_ra_payload;
269 pbuf_chain(ph, pp);
270
271 error = ip6_output_if(ph,
272 netif_ip6_addr(proxy_netif, 0), /* src: link-local */
273 &allnodes_linklocal, /* dst */
274 255, /* hop limit */
275 0, /* traffic class */
276 IP6_NEXTH_ICMP6,
277 proxy_netif);
278 if (error != ERR_OK) {
279 DPRINTF0(("%s: failed to send RA (err=%d)", __func__, error));
280 }
281
282 pbuf_free(pp);
283 pbuf_free(ph);
284}
285
286
287/*
288 * XXX: TODO: Only ra_header::router_lifetime (and hence
289 * ra_header::chksum) need to be changed, so we can precompute it once
290 * and then only update these two fields.
291 */
292static void
293proxy_rtadvd_fill_payload(struct netif *proxy_netif, int is_default)
294{
295 struct pbuf *p;
296 struct ra_header *ra_hdr;
297 struct lladdr_option *lladdr_opt;
298 struct prefix_option *pfx_opt;
299 unsigned int lladdr_optlen;
300
301 LWIP_ASSERT("netif hwaddr too long",
302 proxy_netif->hwaddr_len <= NETIF_MAX_HWADDR_LEN);
303
304 /* type + length + ll addr + round up to 8 octets */
305 lladdr_optlen = (2 + proxy_netif->hwaddr_len + 7) & ~0x7;
306
307 /* actual payload length */
308 unsolicited_ra_payload_length =
309 sizeof(struct ra_header)
310 + lladdr_optlen
311 + sizeof(struct prefix_option) * 1;
312
313 /* Set fields. */
314 ra_hdr = (struct ra_header *)unsolicited_ra_payload;
315 lladdr_opt = (struct lladdr_option *)((u8_t *)ra_hdr + sizeof(struct ra_header));
316 pfx_opt = (struct prefix_option *)((u8_t *)lladdr_opt + lladdr_optlen);
317
318 memset(unsolicited_ra_payload, 0, sizeof(unsolicited_ra_payload));
319
320 ra_hdr->type = ICMP6_TYPE_RA;
321
322#if 0
323 /*
324 * "M" flag. Tell guests to use stateful DHCP6. Disabled here
325 * since we don't provide stateful server.
326 */
327 ra_hdr->flags |= ND6_RA_FLAG_MANAGED_ADDR_CONFIG;
328#endif
329 /*
330 * XXX: TODO: Disable "O" flag for now to match disabled stateless
331 * server. We don't yet get IPv6 nameserver addresses from
332 * HostDnsService, so we have nothing to say, don't tell guests to
333 * come asking.
334 */
335#if 0
336 /*
337 * "O" flag. Tell guests to use DHCP6 for DNS and the like. This
338 * is served by simple stateless server (RFC 3736).
339 *
340 * XXX: "STATEFUL" in the flag name was probably a bug in RFC2461.
341 * It's present in the text, but not in the router configuration
342 * variable name. It's dropped in the text in RFC4861.
343 */
344 ra_hdr->flags |= ND6_RA_FLAG_OTHER_STATEFUL_CONFIG;
345#endif
346
347 if (is_default) {
348 ra_hdr->router_lifetime = PP_HTONS(1200); /* seconds */
349 }
350 else {
351 ra_hdr->router_lifetime = 0;
352 }
353
354 lladdr_opt->type = ND6_OPTION_TYPE_SOURCE_LLADDR;
355 lladdr_opt->length = lladdr_optlen >> 3; /* in units of 8 octets */
356 memcpy(lladdr_opt->addr, proxy_netif->hwaddr, proxy_netif->hwaddr_len);
357
358 pfx_opt->type = ND6_OPTION_TYPE_PREFIX_INFO;
359 pfx_opt->length = 4;
360 pfx_opt->prefix_length = 64;
361 pfx_opt->flags = ND6_PREFIX_FLAG_ON_LINK
362 | ND6_PREFIX_FLAG_AUTONOMOUS;
363 pfx_opt->valid_lifetime = ~0U; /* infinite */
364 pfx_opt->preferred_lifetime = ~0U; /* infinite */
365 pfx_opt->prefix.addr[0] = netif_ip6_addr(proxy_netif, 1)->addr[0];
366 pfx_opt->prefix.addr[1] = netif_ip6_addr(proxy_netif, 1)->addr[1];
367
368
369 /* we need a temp pbuf to calculate the checksum */
370 p = pbuf_alloc(PBUF_IP, unsolicited_ra_payload_length, PBUF_ROM);
371 if (p == NULL) {
372 DPRINTF0(("rtadvd: failed to allocate RA pbuf\n"));
373 return;
374 }
375 p->payload = unsolicited_ra_payload;
376
377 ra_hdr->chksum = ip6_chksum_pseudo(p, IP6_NEXTH_ICMP6, p->len,
378 /* src addr: netif's link-local */
379 netif_ip6_addr(proxy_netif, 0),
380 /* dst addr */
381 &allnodes_linklocal);
382 pbuf_free(p);
383}
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