| 1 | /* -*- indent-tabs-mode: nil; -*- */
|
|---|
| 2 | /**
|
|---|
| 3 | * Simple stateless DHCPv6 (RFC 3736) server.
|
|---|
| 4 | */
|
|---|
| 5 | #define LOG_GROUP LOG_GROUP_NAT_SERVICE
|
|---|
| 6 |
|
|---|
| 7 | #include "winutils.h"
|
|---|
| 8 | #include "dhcp6.h"
|
|---|
| 9 | #include "proxy.h"
|
|---|
| 10 |
|
|---|
| 11 | #include <string.h>
|
|---|
| 12 |
|
|---|
| 13 | #include "lwip/opt.h"
|
|---|
| 14 | #include "lwip/mld6.h"
|
|---|
| 15 | #include "lwip/udp.h"
|
|---|
| 16 |
|
|---|
| 17 |
|
|---|
| 18 | static void dhcp6ds_recv(void *, struct udp_pcb *, struct pbuf *, ip6_addr_t *, u16_t);
|
|---|
| 19 |
|
|---|
| 20 |
|
|---|
| 21 | /* ff02::1:2 - "All_DHCP_Relay_Agents_and_Servers" link-scoped multicast */
|
|---|
| 22 | static /* const */ ip6_addr_t all_dhcp_relays_and_servers = {
|
|---|
| 23 | { PP_HTONL(0xff020000UL), 0, 0, PP_HTONL(0x00010002UL) }
|
|---|
| 24 | };
|
|---|
| 25 |
|
|---|
| 26 | /* ff05::1:3 - "All_DHCP_Servers" site-scoped multicast */
|
|---|
| 27 | static /* const */ ip6_addr_t all_dhcp_servers = {
|
|---|
| 28 | { PP_HTONL(0xff050000UL), 0, 0, PP_HTONL(0x00010003UL) }
|
|---|
| 29 | };
|
|---|
| 30 |
|
|---|
| 31 |
|
|---|
| 32 | static struct udp_pcb *dhcp6ds_pcb;
|
|---|
| 33 |
|
|---|
| 34 | /* prebuilt Server ID option */
|
|---|
| 35 | #define DUID_LL_LEN (/* duid type */ 2 + /* hw type */ 2 + /* ether addr */ 6)
|
|---|
| 36 | static u8_t dhcp6ds_serverid[/* opt */ 2 + /* optlen */ 2 + DUID_LL_LEN];
|
|---|
| 37 |
|
|---|
| 38 | /* prebuilt DNS Servers option */
|
|---|
| 39 | static u8_t dhcp6ds_dns[/* opt */ 2 + /* optlen */ 2 + /* IPv6 addr */ 16];
|
|---|
| 40 |
|
|---|
| 41 |
|
|---|
| 42 | /**
|
|---|
| 43 | * Initialize DHCP6 server.
|
|---|
| 44 | *
|
|---|
| 45 | * Join DHCP6 multicast groups.
|
|---|
| 46 | * Create and bind server pcb.
|
|---|
| 47 | * Prebuild fixed parts of reply.
|
|---|
| 48 | */
|
|---|
| 49 | err_t
|
|---|
| 50 | dhcp6ds_init(struct netif *proxy_netif)
|
|---|
| 51 | {
|
|---|
| 52 | ip6_addr_t *pxaddr, *pxaddr_nonlocal;
|
|---|
| 53 | int i;
|
|---|
| 54 | err_t error;
|
|---|
| 55 |
|
|---|
| 56 | LWIP_ASSERT1(proxy_netif != NULL);
|
|---|
| 57 | LWIP_ASSERT1(proxy_netif->hwaddr_len == 6); /* ethernet */
|
|---|
| 58 |
|
|---|
| 59 | pxaddr = netif_ip6_addr(proxy_netif, 0); /* link local */
|
|---|
| 60 |
|
|---|
| 61 | /*
|
|---|
| 62 | * XXX: TODO: This is a leftover from testing with IPv6 mapped
|
|---|
| 63 | * loopback with a special IPv6->IPv4 mapping hack in pxudp.c
|
|---|
| 64 | */
|
|---|
| 65 | /* advertise ourself as DNS resolver - will be proxied to host */
|
|---|
| 66 | pxaddr_nonlocal = NULL;
|
|---|
| 67 | for (i = 1; i < LWIP_IPV6_NUM_ADDRESSES; ++i) {
|
|---|
| 68 | if (ip6_addr_ispreferred(netif_ip6_addr_state(proxy_netif, i))
|
|---|
| 69 | && !ip6_addr_islinklocal(netif_ip6_addr(proxy_netif, i)))
|
|---|
| 70 | {
|
|---|
| 71 | pxaddr_nonlocal = netif_ip6_addr(proxy_netif, i);
|
|---|
| 72 | break;
|
|---|
| 73 | }
|
|---|
| 74 | }
|
|---|
| 75 | LWIP_ASSERT1(pxaddr_nonlocal != NULL); /* must be configured on the netif */
|
|---|
| 76 |
|
|---|
| 77 |
|
|---|
| 78 | error = mld6_joingroup(pxaddr, &all_dhcp_relays_and_servers);
|
|---|
| 79 | if (error != ERR_OK) {
|
|---|
| 80 | DPRINTF0(("%s: failed to join All_DHCP_Relay_Agents_and_Servers: %s\n",
|
|---|
| 81 | __func__, proxy_lwip_strerr(error)));
|
|---|
| 82 | goto err;
|
|---|
| 83 | }
|
|---|
| 84 |
|
|---|
| 85 | error = mld6_joingroup(pxaddr, &all_dhcp_servers);
|
|---|
| 86 | if (error != ERR_OK) {
|
|---|
| 87 | DPRINTF0(("%s: failed to join All_DHCP_Servers: %s\n",
|
|---|
| 88 | __func__, proxy_lwip_strerr(error)));
|
|---|
| 89 | goto err1;
|
|---|
| 90 | }
|
|---|
| 91 |
|
|---|
| 92 |
|
|---|
| 93 | dhcp6ds_pcb = udp_new_ip6();
|
|---|
| 94 | if (dhcp6ds_pcb == NULL) {
|
|---|
| 95 | DPRINTF0(("%s: failed to allocate PCB\n", __func__));
|
|---|
| 96 | error = ERR_MEM;
|
|---|
| 97 | goto err2;
|
|---|
| 98 | }
|
|---|
| 99 |
|
|---|
| 100 | udp_recv_ip6(dhcp6ds_pcb, dhcp6ds_recv, NULL);
|
|---|
| 101 |
|
|---|
| 102 | error = udp_bind_ip6(dhcp6ds_pcb, pxaddr, DHCP6_SERVER_PORT);
|
|---|
| 103 | if (error != ERR_OK) {
|
|---|
| 104 | DPRINTF0(("%s: failed to bind PCB\n", __func__));
|
|---|
| 105 | goto err3;
|
|---|
| 106 | }
|
|---|
| 107 |
|
|---|
| 108 |
|
|---|
| 109 | #define OPT_SET(buf, off, c) do { \
|
|---|
| 110 | u16_t _s = PP_HTONS(c); \
|
|---|
| 111 | memcpy(&(buf)[off], &_s, sizeof(u16_t)); \
|
|---|
| 112 | } while (0)
|
|---|
| 113 |
|
|---|
| 114 | #define SERVERID_SET(off, c) OPT_SET(dhcp6ds_serverid, (off), (c))
|
|---|
| 115 | #define DNSSRV_SET(off, c) OPT_SET(dhcp6ds_dns, (off), (c))
|
|---|
| 116 |
|
|---|
| 117 | SERVERID_SET(0, DHCP6_OPTION_SERVERID);
|
|---|
| 118 | SERVERID_SET(2, DUID_LL_LEN);
|
|---|
| 119 | SERVERID_SET(4, DHCP6_DUID_LL);
|
|---|
| 120 | SERVERID_SET(6, ARES_HRD_ETHERNET);
|
|---|
| 121 | memcpy(&dhcp6ds_serverid[8], proxy_netif->hwaddr, 6);
|
|---|
| 122 |
|
|---|
| 123 | DNSSRV_SET(0, DHCP6_OPTION_DNS_SERVERS);
|
|---|
| 124 | DNSSRV_SET(2, 16); /* one IPv6 address */
|
|---|
| 125 | /*
|
|---|
| 126 | * XXX: TODO: This is a leftover from testing with IPv6 mapped
|
|---|
| 127 | * loopback with a special IPv6->IPv4 mapping hack in pxudp.c
|
|---|
| 128 | */
|
|---|
| 129 | memcpy(&dhcp6ds_dns[4], pxaddr_nonlocal, sizeof(ip6_addr_t));
|
|---|
| 130 |
|
|---|
| 131 | #undef SERVERID_SET
|
|---|
| 132 | #undef DNSSRV_SET
|
|---|
| 133 |
|
|---|
| 134 | return ERR_OK;
|
|---|
| 135 |
|
|---|
| 136 |
|
|---|
| 137 | err3:
|
|---|
| 138 | udp_remove(dhcp6ds_pcb);
|
|---|
| 139 | dhcp6ds_pcb = NULL;
|
|---|
| 140 | err2:
|
|---|
| 141 | mld6_leavegroup(pxaddr, &all_dhcp_servers);
|
|---|
| 142 | err1:
|
|---|
| 143 | mld6_leavegroup(pxaddr, &all_dhcp_relays_and_servers);
|
|---|
| 144 | err:
|
|---|
| 145 | return error;
|
|---|
| 146 | }
|
|---|
| 147 |
|
|---|
| 148 |
|
|---|
| 149 | static u8_t dhcp6ds_reply_buf[1024];
|
|---|
| 150 |
|
|---|
| 151 | static void
|
|---|
| 152 | dhcp6ds_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p,
|
|---|
| 153 | ip6_addr_t *addr, u16_t port)
|
|---|
| 154 | {
|
|---|
| 155 | u8_t msg_header[4];
|
|---|
| 156 | unsigned int msg_type, msg_tid;
|
|---|
| 157 | int copied;
|
|---|
| 158 | size_t roff;
|
|---|
| 159 | struct pbuf *q;
|
|---|
| 160 | err_t error;
|
|---|
| 161 |
|
|---|
| 162 | LWIP_UNUSED_ARG(arg);
|
|---|
| 163 | LWIP_ASSERT1(p != NULL);
|
|---|
| 164 |
|
|---|
| 165 | copied = pbuf_copy_partial(p, msg_header, sizeof(msg_header), 0);
|
|---|
| 166 | if (copied != sizeof(msg_header)) {
|
|---|
| 167 | DPRINTF(("%s: message header truncated\n", __func__));
|
|---|
| 168 | pbuf_free(p);
|
|---|
| 169 | return;
|
|---|
| 170 | }
|
|---|
| 171 | pbuf_header(p, -(s16_t)sizeof(msg_header));
|
|---|
| 172 |
|
|---|
| 173 | msg_type = msg_header[0];
|
|---|
| 174 | msg_tid = (msg_header[1] << 16) | (msg_header[2] << 8) | msg_header[3];
|
|---|
| 175 | DPRINTF(("%s: type %u, tid 0x%6x\n", __func__, msg_type, msg_tid));
|
|---|
| 176 | if (msg_type != DHCP6_INFORMATION_REQUEST) { /* TODO:? RELAY_FORW */
|
|---|
| 177 | pbuf_free(p);
|
|---|
| 178 | return;
|
|---|
| 179 | }
|
|---|
| 180 |
|
|---|
| 181 | roff = 0;
|
|---|
| 182 |
|
|---|
| 183 | msg_header[0] = DHCP6_REPLY;
|
|---|
| 184 | memcpy(dhcp6ds_reply_buf + roff, msg_header, sizeof(msg_header));
|
|---|
| 185 | roff += sizeof(msg_header);
|
|---|
| 186 |
|
|---|
| 187 |
|
|---|
| 188 | /* loop over options */
|
|---|
| 189 | while (p->tot_len > 0) {
|
|---|
| 190 | u16_t opt, optlen;
|
|---|
| 191 |
|
|---|
| 192 | /* fetch option code */
|
|---|
| 193 | copied = pbuf_copy_partial(p, &opt, sizeof(opt), 0);
|
|---|
| 194 | if (copied != sizeof(opt)) {
|
|---|
| 195 | DPRINTF(("%s: option header truncated\n", __func__));
|
|---|
| 196 | pbuf_free(p);
|
|---|
| 197 | return;
|
|---|
| 198 | }
|
|---|
| 199 | pbuf_header(p, -(s16_t)sizeof(opt));
|
|---|
| 200 | opt = ntohs(opt);
|
|---|
| 201 |
|
|---|
| 202 | /* fetch option length */
|
|---|
| 203 | copied = pbuf_copy_partial(p, &optlen, sizeof(optlen), 0);
|
|---|
| 204 | if (copied != sizeof(optlen)) {
|
|---|
| 205 | DPRINTF(("%s: option %u length truncated\n", __func__, opt));
|
|---|
| 206 | pbuf_free(p);
|
|---|
| 207 | return;
|
|---|
| 208 | }
|
|---|
| 209 | pbuf_header(p, -(s16_t)sizeof(optlen));
|
|---|
| 210 | optlen = ntohs(optlen);
|
|---|
| 211 |
|
|---|
| 212 | /* enough data? */
|
|---|
| 213 | if (optlen > p->tot_len) {
|
|---|
| 214 | DPRINTF(("%s: option %u truncated: expect %u, got %u\n",
|
|---|
| 215 | __func__, opt, optlen, p->tot_len));
|
|---|
| 216 | pbuf_free(p);
|
|---|
| 217 | return;
|
|---|
| 218 | }
|
|---|
| 219 |
|
|---|
| 220 | DPRINTF2(("%s: option %u length %u\n", __func__, opt, optlen));
|
|---|
| 221 |
|
|---|
| 222 | if (opt == DHCP6_OPTION_CLIENTID) {
|
|---|
| 223 | u16_t s;
|
|---|
| 224 |
|
|---|
| 225 | /* "A DUID can be no more than 128 octets long (not
|
|---|
| 226 | including the type code)." */
|
|---|
| 227 | if (optlen > 130) {
|
|---|
| 228 | DPRINTF(("%s: client DUID too long: %u\n", __func__, optlen));
|
|---|
| 229 | pbuf_free(p);
|
|---|
| 230 | return;
|
|---|
| 231 | }
|
|---|
| 232 |
|
|---|
| 233 | s = PP_HTONS(DHCP6_OPTION_CLIENTID);
|
|---|
| 234 | memcpy(dhcp6ds_reply_buf + roff, &s, sizeof(s));
|
|---|
| 235 | roff += sizeof(s);
|
|---|
| 236 |
|
|---|
| 237 | s = ntohs(optlen);
|
|---|
| 238 | memcpy(dhcp6ds_reply_buf + roff, &s, sizeof(s));
|
|---|
| 239 | roff += sizeof(s);
|
|---|
| 240 |
|
|---|
| 241 | pbuf_copy_partial(p, dhcp6ds_reply_buf + roff, optlen, 0);
|
|---|
| 242 | roff += optlen;
|
|---|
| 243 | }
|
|---|
| 244 | else if (opt == DHCP6_OPTION_ORO) {
|
|---|
| 245 | u16_t *opts;
|
|---|
| 246 | int i, nopts;
|
|---|
| 247 |
|
|---|
| 248 | if (optlen % 2 != 0) {
|
|---|
| 249 | DPRINTF2(("%s: Option Request of odd length\n", __func__));
|
|---|
| 250 | goto bad_oro;
|
|---|
| 251 | }
|
|---|
| 252 | nopts = optlen / 2;
|
|---|
| 253 |
|
|---|
| 254 | opts = (u16_t *)malloc(optlen);
|
|---|
| 255 | if (opts == NULL) {
|
|---|
| 256 | DPRINTF2(("%s: failed to allocate space for Option Request\n",
|
|---|
| 257 | __func__));
|
|---|
| 258 | goto bad_oro;
|
|---|
| 259 | }
|
|---|
| 260 |
|
|---|
| 261 | pbuf_copy_partial(p, opts, optlen, 0);
|
|---|
| 262 | for (i = 0; i < nopts; ++i) {
|
|---|
| 263 | opt = ntohs(opts[i]);
|
|---|
| 264 | DPRINTF2(("> request option %u\n", opt));
|
|---|
| 265 | };
|
|---|
| 266 | free(opts);
|
|---|
| 267 |
|
|---|
| 268 | bad_oro: /* empty */;
|
|---|
| 269 | }
|
|---|
| 270 |
|
|---|
| 271 | pbuf_header(p, -optlen); /* go to next option */
|
|---|
| 272 | }
|
|---|
| 273 | pbuf_free(p); /* done */
|
|---|
| 274 |
|
|---|
| 275 |
|
|---|
| 276 | memcpy(dhcp6ds_reply_buf + roff, dhcp6ds_serverid, sizeof(dhcp6ds_serverid));
|
|---|
| 277 | roff += sizeof(dhcp6ds_serverid);
|
|---|
| 278 |
|
|---|
| 279 | memcpy(dhcp6ds_reply_buf + roff, dhcp6ds_dns, sizeof(dhcp6ds_dns));
|
|---|
| 280 | roff += sizeof(dhcp6ds_dns);
|
|---|
| 281 |
|
|---|
| 282 | q = pbuf_alloc(PBUF_RAW, roff, PBUF_RAM);
|
|---|
| 283 | if (q == NULL) {
|
|---|
| 284 | DPRINTF(("%s: pbuf_alloc(%d) failed\n", __func__, (int)roff));
|
|---|
| 285 | return;
|
|---|
| 286 | }
|
|---|
| 287 |
|
|---|
| 288 | error = pbuf_take(q, dhcp6ds_reply_buf, roff);
|
|---|
| 289 | if (error != ERR_OK) {
|
|---|
| 290 | DPRINTF(("%s: pbuf_take(%d) failed: %s\n",
|
|---|
| 291 | __func__, (int)roff, proxy_lwip_strerr(error)));
|
|---|
| 292 | pbuf_free(q);
|
|---|
| 293 | return;
|
|---|
| 294 | }
|
|---|
| 295 |
|
|---|
| 296 | error = udp_sendto_ip6(pcb, q, addr, port);
|
|---|
| 297 | if (error != ERR_OK) {
|
|---|
| 298 | DPRINTF(("%s: udp_sendto failed: %s\n",
|
|---|
| 299 | __func__, proxy_lwip_strerr(error)));
|
|---|
| 300 | }
|
|---|
| 301 |
|
|---|
| 302 | pbuf_free(q);
|
|---|
| 303 | }
|
|---|
