/**
- * Copyright (C) 2012 Steven Barth <steven@midlink.org>
+ * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2 as published by
#include <time.h>
#include <fcntl.h>
#include <errno.h>
+#include <stdlib.h>
#include <signal.h>
#include <limits.h>
#include <resolv.h>
#include <net/ethernet.h>
#include "odhcp6c.h"
+#include "md5.h"
#define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE;
static bool accept_reconfig = false;
+// Reconfigure key
+static uint8_t reconf_key[16];
+
int init_dhcpv6(const char *ifname, int request_pd)
htons(DHCPV6_OPT_DNS_DOMAIN),
htons(DHCPV6_OPT_NTP_SERVER),
htons(DHCPV6_OPT_SIP_SERVER_A),
- htons(DHCPV6_OPT_SIP_SERVER_D)};
+ htons(DHCPV6_OPT_SIP_SERVER_D),
+ htons(DHCPV6_OPT_PD_EXCLUDE)};
odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
// Build IA_PDs
size_t ia_pd_entries, ia_pd_len = 0;
- void *ia_pd = NULL;
struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
ia_pd_entries /= sizeof(*e);
struct dhcpv6_ia_hdr hdr_ia_pd = {
1, 0, 0
};
- struct dhcpv6_ia_prefix pref = {
- .type = htons(DHCPV6_OPT_IA_PREFIX),
- .len = htons(25), .prefix = request_prefix
- };
-
- struct dhcpv6_ia_prefix p[ia_pd_entries];
+ uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
for (size_t i = 0; i < ia_pd_entries; ++i) {
- p[i].type = htons(DHCPV6_OPT_IA_PREFIX);
- p[i].len = htons(sizeof(p[i]) - 4U);
- p[i].preferred = 0;
- p[i].valid = 0;
- p[i].prefix = e[i].length;
- p[i].addr = e[i].target;
+ uint8_t ex_len = 0;
+ if (e[i].priority > 0)
+ ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
+
+ struct dhcpv6_ia_prefix p = {
+ .type = htons(DHCPV6_OPT_IA_PREFIX),
+ .len = htons(sizeof(p) - 4U + ex_len),
+ .prefix = e[i].length,
+ .addr = e[i].target
+ };
+
+ memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
+ ia_pd_len += sizeof(p);
+
+ if (ex_len) {
+ ia_pd[ia_pd_len++] = 0;
+ ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
+ ia_pd[ia_pd_len++] = 0;
+ ia_pd[ia_pd_len++] = ex_len - 4;
+ ia_pd[ia_pd_len++] = e[i].priority;
+
+ uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
+ excl >>= (64 - e[i].priority);
+ excl <<= 8 - ((e[i].priority - e[i].length) % 8);
+
+ for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
+ ia_pd[ia_pd_len + i] = excl & 0xff;
+ ia_pd_len += ex_len - 5;
+ }
}
- ia_pd = p;
- ia_pd_len = sizeof(p);
- hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
- if (request_prefix > 0 &&
+ struct dhcpv6_ia_prefix pref = {
+ .type = htons(DHCPV6_OPT_IA_PREFIX),
+ .len = htons(25), .prefix = request_prefix
+ };
+ if (request_prefix > 0 && ia_pd_len == 0 &&
(type == DHCPV6_MSG_SOLICIT ||
type == DHCPV6_MSG_REQUEST)) {
- ia_pd = &pref;
+ ia_pd = (uint8_t*)&pref;
ia_pd_len = sizeof(pref);
- hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
}
+ hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
// Build IA_NAs
size_t ia_na_entries, ia_na_len = 0;
uint8_t *end = ((uint8_t*)buf) + len, *odata;
uint16_t otype, olen;
- bool clientid_ok = false, serverid_ok = false;
+ bool clientid_ok = false, serverid_ok = false, rcauth_ok = false;
size_t client_id_len, server_id_len;
void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
- dhcpv6_for_each_option(&rep[1], end, otype, olen, odata)
- if (otype == DHCPV6_OPT_CLIENTID)
+ dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
+ if (otype == DHCPV6_OPT_CLIENTID) {
clientid_ok = (olen + 4U == client_id_len) && !memcmp(
&odata[-4], client_id, client_id_len);
- else if (otype == DHCPV6_OPT_SERVERID)
+ } else if (otype == DHCPV6_OPT_SERVERID) {
serverid_ok = (olen + 4U == server_id_len) && !memcmp(
&odata[-4], server_id, server_id_len);
+ } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
+ sizeof(struct dhcpv6_auth_reconfigure)) {
+ struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
+ if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
+ continue;
+
+ md5_state_t md5;
+ uint8_t serverhash[16], secretbytes[16], hash[16];
+ memcpy(serverhash, r->key, sizeof(serverhash));
+ memset(r->key, 0, sizeof(r->key));
+ memcpy(secretbytes, reconf_key, sizeof(secretbytes));
+
+ for (size_t i = 0; i < sizeof(secretbytes); ++i)
+ secretbytes[i] ^= 0x36;
+
+ md5_init(&md5);
+ md5_append(&md5, secretbytes, sizeof(secretbytes));
+ md5_append(&md5, buf, len);
+ md5_finish(&md5, hash);
+
+ for (size_t i = 0; i < sizeof(secretbytes); ++i) {
+ secretbytes[i] ^= 0x36;
+ secretbytes[i] ^= 0x5c;
+ }
+
+ md5_init(&md5);
+ md5_append(&md5, secretbytes, sizeof(secretbytes));
+ md5_append(&md5, hash, 16);
+ md5_finish(&md5, hash);
+
+ rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
+ }
+ }
+
+ if (rep->msg_type == DHCPV6_MSG_RECONF && !rcauth_ok)
+ return false;
return clientid_ok && (serverid_ok || server_id_len == 0);
}
uint32_t refresh = ntohl(*((uint32_t*)odata));
if (refresh < (uint32_t)t1)
t1 = refresh;
+ } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
+ sizeof(struct dhcpv6_auth_reconfigure)) {
+ struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
+ if (r->protocol == 3 && r->algorithm == 1 &&
+ r->reconf_type == 1)
+ memcpy(reconf_key, r->key, sizeof(r->key));
} else if (otype != DHCPV6_OPT_CLIENTID &&
otype != DHCPV6_OPT_SERVERID) {
odhcp6c_add_state(STATE_CUSTOM_OPTS,
entry.length = prefix->prefix;
entry.target = prefix->addr;
- odhcp6c_update_entry(STATE_IA_PD, &entry);
+ // Parse PD-exclude
+ bool ok = true;
+ uint16_t stype, slen;
+ uint8_t *sdata;
+ dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
+ odata + olen, stype, slen, sdata) {
+ if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
+ continue;
+
+ uint8_t elen = sdata[0];
+ if (elen > 64)
+ elen = 64;
+
+ if (elen <= 32 || elen <= entry.length) {
+ ok = false;
+ continue;
+ }
+
+
+ uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
+ if (slen <= bytes) {
+ ok = false;
+ continue;
+ }
+
+ uint32_t exclude = 0;
+ do {
+ exclude = exclude << 8 | sdata[bytes];
+ } while (--bytes);
+
+ exclude >>= 8 - ((elen - entry.length) % 8);
+ exclude <<= 64 - elen;
+
+ // Abusing router & priority fields for exclusion
+ entry.router = entry.target;
+ entry.router.s6_addr32[1] |= htonl(exclude);
+ entry.priority = elen;
+ }
+
+ if (ok)
+ odhcp6c_update_entry(STATE_IA_PD, &entry);
+
+ entry.priority = 0;
+ memset(&entry.router, 0, sizeof(entry.router));
} else if (otype == DHCPV6_OPT_IA_ADDR) {
struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
if (olen + 4U < sizeof(*addr))