diff options
Diffstat (limited to 'src/dhcpv6-ia.c')
| -rw-r--r-- | src/dhcpv6-ia.c | 893 |
1 files changed, 893 insertions, 0 deletions
diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c new file mode 100644 index 0000000..89d3a15 --- /dev/null +++ b/src/dhcpv6-ia.c @@ -0,0 +1,893 @@ +/** + * Copyright (C) 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 + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include "odhcpd.h" +#include "dhcpv6.h" +#include "dhcpv4.h" +#include "md5.h" + +#include <time.h> +#include <errno.h> +#include <fcntl.h> +#include <alloca.h> +#include <resolv.h> +#include <limits.h> +#include <stdlib.h> +#include <unistd.h> +#include <arpa/inet.h> +#include <sys/timerfd.h> + + +static void update(struct interface *iface); +static void reconf_timer(struct uloop_timeout *event); +static struct uloop_timeout reconf_event = {.cb = reconf_timer}; +static int socket_fd = -1; +static uint32_t serial = 0; + + +int dhcpv6_ia_init(int dhcpv6_socket) +{ + socket_fd = dhcpv6_socket; + uloop_timeout_set(&reconf_event, 2000); + return 0; +} + + +int setup_dhcpv6_ia_interface(struct interface *iface, bool enable) +{ + if (!enable && iface->ia_assignments.next) { + struct dhcpv6_assignment *c; + while (!list_empty(&iface->ia_assignments)) { + c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head); + list_del(&c->head); + free(c); + } + } + + if (iface->dhcpv6 == RELAYD_SERVER) { + if (!iface->ia_assignments.next) + INIT_LIST_HEAD(&iface->ia_assignments); + + if (list_empty(&iface->ia_assignments)) { + struct dhcpv6_assignment *border = calloc(1, sizeof(*border)); + border->length = 64; + list_add(&border->head, &iface->ia_assignments); + } + + update(iface); + + // Parse static entries + struct lease *lease; + list_for_each_entry(lease, &leases, head) { + // Construct entry + struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len); + a->clid_len = lease->duid_len; + a->length = 128; + a->assigned = lease->hostid; + odhcpd_urandom(a->key, sizeof(a->key)); + memcpy(a->clid_data, lease->duid, a->clid_len); + memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac)); + + // Assign to all interfaces + struct dhcpv6_assignment *c; + list_for_each_entry(c, &iface->ia_assignments, head) { + if (c->length != 128 || c->assigned > a->assigned) { + list_add_tail(&a->head, &c->head); + } else if (c->assigned == a->assigned) { + // Already an assignment with that number + break; + } + } + + if (a->head.next) { + if (lease->hostname[0]) { + free(a->hostname); + a->hostname = strdup(lease->hostname); + } + } else { + free(a); + } + } + } + return 0; +} + + +static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign) +{ + struct { + struct dhcpv6_client_header hdr; + uint16_t srvid_type; + uint16_t srvid_len; + uint16_t duid_type; + uint16_t hardware_type; + uint8_t mac[6]; + uint16_t msg_type; + uint16_t msg_len; + uint8_t msg_id; + struct dhcpv6_auth_reconfigure auth; + uint16_t clid_type; + uint16_t clid_len; + uint8_t clid_data[128]; + } __attribute__((packed)) reconf_msg = { + .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}}, + .srvid_type = htons(DHCPV6_OPT_SERVERID), + .srvid_len = htons(10), + .duid_type = htons(3), + .hardware_type = htons(1), + .msg_type = htons(DHCPV6_OPT_RECONF_MSG), + .msg_len = htons(1), + .msg_id = DHCPV6_MSG_RENEW, + .auth = {htons(DHCPV6_OPT_AUTH), + htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0, + {htonl(time(NULL)), htonl(++serial)}, 2, {0}}, + .clid_type = htons(DHCPV6_OPT_CLIENTID), + .clid_len = htons(assign->clid_len), + .clid_data = {0}, + }; + + odhcpd_get_mac(iface, reconf_msg.mac); + memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len); + struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len}; + + md5_ctx_t md5; + uint8_t secretbytes[16]; + memcpy(secretbytes, assign->key, sizeof(secretbytes)); + + for (size_t i = 0; i < sizeof(secretbytes); ++i) + secretbytes[i] ^= 0x36; + + md5_begin(&md5); + md5_hash(secretbytes, sizeof(secretbytes), &md5); + md5_hash(iov.iov_base, iov.iov_len, &md5); + md5_end(reconf_msg.auth.key, &md5); + + for (size_t i = 0; i < sizeof(secretbytes); ++i) { + secretbytes[i] ^= 0x36; + secretbytes[i] ^= 0x5c; + } + + md5_begin(&md5); + md5_hash(secretbytes, sizeof(secretbytes), &md5); + md5_hash(reconf_msg.auth.key, 16, &md5); + md5_end(reconf_msg.auth.key, &md5); + + return odhcpd_send(socket_fd, &assign->peer, &iov, 1, iface); +} + + +void dhcpv6_write_statefile(void) +{ + if (config.dhcp_statefile) { + time_t now = odhcpd_time(), wall_time = time(NULL); + int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644); + if (fd < 0) + return; + + lockf(fd, F_LOCK, 0); + ftruncate(fd, 0); + + FILE *fp = fdopen(fd, "w"); + if (!fp) { + close(fd); + return; + } + + struct interface *iface; + list_for_each_entry(iface, &interfaces, head) { + if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER) + continue; + + if (iface->dhcpv6 == RELAYD_SERVER) { + struct dhcpv6_assignment *c; + list_for_each_entry(c, &iface->ia_assignments, head) { + if (c->clid_len == 0) + continue; + + char ipbuf[INET6_ADDRSTRLEN]; + char leasebuf[512]; + char duidbuf[264]; + odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len); + + // iface DUID iaid hostname lifetime assigned length [addrs...] + int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ", + iface->ifname, duidbuf, ntohl(c->iaid), + (c->hostname ? c->hostname : "-"), + (unsigned)(c->valid_until > now ? + (c->valid_until - now + wall_time) : 0), + c->assigned, (unsigned)c->length); + + struct in6_addr addr; + for (size_t i = 0; i < iface->ia_addr_len; ++i) { + if (iface->ia_addr[i].prefix > 64) + continue; + + addr = iface->ia_addr[i].addr; + if (c->length == 128) + addr.s6_addr32[3] = htonl(c->assigned); + else + addr.s6_addr32[1] |= htonl(c->assigned); + inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1); + + if (c->length == 128 && c->hostname && i == 0) + fprintf(fp, "%s\t%s\n", ipbuf, c->hostname); + + l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length); + } + leasebuf[l - 1] = '\n'; + fwrite(leasebuf, 1, l, fp); + } + } + + if (iface->dhcpv4 == RELAYD_SERVER) { + struct dhcpv4_assignment *c; + list_for_each_entry(c, &iface->dhcpv4_assignments, head) { + char ipbuf[INET6_ADDRSTRLEN]; + char leasebuf[512]; + char duidbuf[16]; + odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr)); + + // iface DUID iaid hostname lifetime assigned length [addrs...] + int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ", + iface->ifname, duidbuf, + (c->hostname ? c->hostname : "-"), + (unsigned)(c->valid_until > now ? + (c->valid_until - now + wall_time) : 0), + c->addr); + + struct in_addr addr = {htonl(c->addr)}; + inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1); + + if (c->hostname[0]) + fprintf(fp, "%s\t%s\n", ipbuf, c->hostname); + + l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf); + leasebuf[l - 1] = '\n'; + fwrite(leasebuf, 1, l, fp); + } + } + } + + fclose(fp); + } + + if (config.dhcp_cb) { + char *argv[2] = {config.dhcp_cb, NULL}; + if (!vfork()) { + execv(argv[0], argv); + _exit(128); + } + } +} + + +static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add) +{ + if (a->length > 64) + return; + + for (size_t i = 0; i < iface->ia_addr_len; ++i) { + struct in6_addr prefix = iface->ia_addr[i].addr; + prefix.s6_addr32[1] |= htonl(a->assigned); + odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add); + } +} + + +static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign) +{ + struct dhcpv6_assignment *c; + if (iface->ia_addr_len < 1) + return false; + + // Try honoring the hint first + uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1; + if (assign->assigned) { + list_for_each_entry(c, &iface->ia_assignments, head) { + if (c->length == 128) + continue; + + if (assign->assigned >= current && assign->assigned + asize < c->assigned) { + list_add_tail(&assign->head, &c->head); + apply_lease(iface, assign, true); + return true; + } + + if (c->assigned != 0) + current = (c->assigned + (1 << (64 - c->length))); + } + } + + // Fallback to a variable assignment + current = 1; + list_for_each_entry(c, &iface->ia_assignments, head) { + if (c->length == 128) + continue; + + current = (current + asize) & (~asize); + if (current + asize < c->assigned) { + assign->assigned = current; + list_add_tail(&assign->head, &c->head); + apply_lease(iface, assign, true); + return true; + } + + if (c->assigned != 0) + current = (c->assigned + (1 << (64 - c->length))); + } + + return false; +} + + +static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign) +{ + if (iface->ia_addr_len < 1) + return false; + + // Seed RNG with checksum of DUID + uint32_t seed = 0; + for (size_t i = 0; i < assign->clid_len; ++i) + seed += assign->clid_data[i]; + srand(seed); + + // Try to assign up to 100x + for (size_t i = 0; i < 100; ++i) { + uint32_t try; + do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100); + + struct dhcpv6_assignment *c; + list_for_each_entry(c, &iface->ia_assignments, head) { + if (c->assigned > try || c->length != 128) { + assign->assigned = try; + list_add_tail(&assign->head, &c->head); + return true; + } else if (c->assigned == try) { + break; + } + } + } + + return false; +} + + +static int prefixcmp(const void *va, const void *vb) +{ + const struct odhcpd_ipaddr *a = va, *b = vb; + uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1; + uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1; + return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0; +} + + +static void update(struct interface *iface) +{ + struct odhcpd_ipaddr addr[8]; + memset(addr, 0, sizeof(addr)); + int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8); + + if (len < 0) + return; + + qsort(addr, len, sizeof(*addr), prefixcmp); + + time_t now = odhcpd_time(); + int minprefix = -1; + + for (int i = 0; i < len; ++i) { + if (addr[i].prefix > minprefix) + minprefix = addr[i].prefix; + + addr[i].addr.s6_addr32[2] = 0; + addr[i].addr.s6_addr32[3] = 0; + + if (addr[i].preferred < UINT32_MAX - now) + addr[i].preferred += now; + + if (addr[i].valid < UINT32_MAX - now) + addr[i].valid += now; + } + + struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head); + border->assigned = 1 << (64 - minprefix); + + bool change = len != (int)iface->ia_addr_len; + for (int i = 0; !change && i < len; ++i) + if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] || + addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] || + (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) || + (addr[i].valid > now + 7200) != (iface->ia_addr[i].valid > now + 7200)) + change = true; + + if (change) { + struct dhcpv6_assignment *c; + list_for_each_entry(c, &iface->ia_assignments, head) + if (c != border) + apply_lease(iface, c, false); + } + + memcpy(iface->ia_addr, addr, len * sizeof(*addr)); + iface->ia_addr_len = len; + + if (change) { // Addresses / prefixes have changed + struct list_head reassign = LIST_HEAD_INIT(reassign); + struct dhcpv6_assignment *c, *d; + list_for_each_entry_safe(c, d, &iface->ia_assignments, head) { + if (c->clid_len == 0 || c->valid_until < now) + continue; + + if (c->length < 128 && c->assigned >= border->assigned && c != border) + list_move(&c->head, &reassign); + else if (c != border) + apply_lease(iface, c, true); + + if (c->accept_reconf && c->reconf_cnt == 0) { + c->reconf_cnt = 1; + c->reconf_sent = now; + send_reconf(iface, c); + + // Leave all other assignments of that client alone + struct dhcpv6_assignment *a; + list_for_each_entry(a, &iface->ia_assignments, head) + if (a != c && a->clid_len == c->clid_len && + !memcmp(a->clid_data, c->clid_data, a->clid_len)) + c->reconf_cnt = INT_MAX; + } + } + + while (!list_empty(&reassign)) { + c = list_first_entry(&reassign, struct dhcpv6_assignment, head); + list_del(&c->head); + if (!assign_pd(iface, c)) { + c->assigned = 0; + list_add(&c->head, &iface->ia_assignments); + } + } + + dhcpv6_write_statefile(); + } +} + + +static void reconf_timer(struct uloop_timeout *event) +{ + time_t now = odhcpd_time(); + struct interface *iface; + list_for_each_entry(iface, &interfaces, head) { + if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL) + continue; + + struct dhcpv6_assignment *a, *n; + list_for_each_entry_safe(a, n, &iface->ia_assignments, head) { + if (a->valid_until < now) { + if ((a->length < 128 && a->clid_len > 0) || + (a->length == 128 && a->clid_len == 0)) { + list_del(&a->head); + free(a->hostname); + free(a); + } + } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 && + now > a->reconf_sent + (1 << a->reconf_cnt)) { + ++a->reconf_cnt; + a->reconf_sent = now; + send_reconf(iface, a); + } + } + + if (iface->ia_reconf) { + update(iface); + iface->ia_reconf = false; + } + } + + uloop_timeout_set(event, 2000); +} + + +static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status, + const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a, + struct interface *iface, bool request) +{ + if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix)) + return 0; + + struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0}; + size_t datalen = sizeof(out); + time_t now = odhcpd_time(); + + if (status) { + struct __attribute__((packed)) { + uint16_t type; + uint16_t len; + uint16_t value; + } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4), + htons(status)}; + + memcpy(buf + datalen, &stat, sizeof(stat)); + datalen += sizeof(stat); + } else { + if (a) { + uint32_t pref = 3600; + uint32_t valid = 3600; + bool have_non_ula = false; + for (size_t i = 0; i < iface->ia_addr_len; ++i) + if ((iface->ia_addr[i].addr.s6_addr[0] & 0xfe) != 0xfc) + have_non_ula = true; + + for (size_t i = 0; i < iface->ia_addr_len; ++i) { + uint32_t prefix_pref = iface->ia_addr[i].preferred - now; + uint32_t prefix_valid = iface->ia_addr[i].valid - now; + + if (iface->ia_addr[i].prefix > 64 || + iface->ia_addr[i].preferred <= (uint32_t)now) + continue; + + // ULA-deprecation compatibility workaround + if ((iface->ia_addr[i].addr.s6_addr[0] & 0xfe) == 0xfc && + a->length == 128 && have_non_ula && + iface->deprecate_ula_if_public_avail) + continue; + + if (prefix_pref > 86400) + prefix_pref = 86400; + + if (prefix_valid > 86400) + prefix_valid = 86400; + + if (a->length < 128) { + struct dhcpv6_ia_prefix p = { + .type = htons(DHCPV6_OPT_IA_PREFIX), + .len = htons(sizeof(p) - 4), + .preferred = htonl(prefix_pref), + .valid = htonl(prefix_valid), + .prefix = a->length, + .addr = iface->ia_addr[i].addr + }; + p.addr.s6_addr32[1] |= htonl(a->assigned); + + if (datalen + sizeof(p) > buflen || a->assigned == 0) + continue; + + memcpy(buf + datalen, &p, sizeof(p)); + datalen += sizeof(p); + } else { + struct dhcpv6_ia_addr n = { + .type = htons(DHCPV6_OPT_IA_ADDR), + .len = htons(sizeof(n) - 4), + .addr = iface->ia_addr[i].addr, + .preferred = htonl(prefix_pref), + .valid = htonl(prefix_valid) + }; + n.addr.s6_addr32[3] = htonl(a->assigned); + + if (datalen + sizeof(n) > buflen || a->assigned == 0) + continue; + + memcpy(buf + datalen, &n, sizeof(n)); + datalen += sizeof(n); + } + + // Calculate T1 / T2 based on non-deprecated addresses + if (prefix_pref > 0) { + if (prefix_pref < pref) + pref = prefix_pref; + + if (prefix_valid < valid) + valid = prefix_valid; + } + } + + a->valid_until = valid + now; + out.t1 = htonl(pref * 5 / 10); + out.t2 = htonl(pref * 8 / 10); + + if (!out.t1) + out.t1 = htonl(1); + + if (!out.t2) + out.t2 = htonl(1); + } + + if (!request) { + uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4; + uint16_t otype, olen; + dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) { + struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4]; + struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4]; + if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) && + (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4)) + continue; + + bool found = false; + if (a) { + for (size_t i = 0; i < iface->ia_addr_len; ++i) { + if (iface->ia_addr[i].prefix > 64 || + iface->ia_addr[i].preferred <= (uint32_t)now) + continue; + + struct in6_addr addr = iface->ia_addr[i].addr; + if (ia->type == htons(DHCPV6_OPT_IA_PD)) { + addr.s6_addr32[1] |= htonl(a->assigned); + + if (IN6_ARE_ADDR_EQUAL(&p->addr, &addr) && + p->prefix == a->length) + found = true; + } else { + addr.s6_addr32[3] = htonl(a->assigned); + + if (IN6_ARE_ADDR_EQUAL(&n->addr, &addr)) + found = true; + } + } + } + + if (!found) { + if (otype == DHCPV6_OPT_IA_PREFIX) { + struct dhcpv6_ia_prefix inv = { + .type = htons(DHCPV6_OPT_IA_PREFIX), + .len = htons(sizeof(inv) - 4), + .preferred = 0, + .valid = 0, + .prefix = p->prefix, + .addr = p->addr + }; + + if (datalen + sizeof(inv) > buflen) + continue; + + memcpy(buf + datalen, &inv, sizeof(inv)); + datalen += sizeof(inv); + } else { + struct dhcpv6_ia_addr inv = { + .type = htons(DHCPV6_OPT_IA_ADDR), + .len = htons(sizeof(inv) - 4), + .addr = n->addr, + .preferred = 0, + .valid = 0 + }; + + if (datalen + sizeof(inv) > buflen) + continue; + + memcpy(buf + datalen, &inv, sizeof(inv)); + datalen += sizeof(inv); + } + } + } + } + } + + out.len = htons(datalen - 4); + memcpy(buf, &out, sizeof(out)); + return datalen; +} + + +size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface, + const struct sockaddr_in6 *addr, const void *data, const uint8_t *end) +{ + time_t now = odhcpd_time(); + size_t response_len = 0; + const struct dhcpv6_client_header *hdr = data; + uint8_t *start = (uint8_t*)&hdr[1], *odata; + uint16_t otype, olen; + + // Find and parse client-id and hostname + bool accept_reconf = false; + uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; + char hostname[256]; + size_t hostname_len = 0; + dhcpv6_for_each_option(start, end, otype, olen, odata) { + if (otype == DHCPV6_OPT_CLIENTID) { + clid_data = odata; + clid_len = olen; + + if (olen == 14 && odata[0] == 0 && odata[1] == 1) + memcpy(mac, &odata[8], sizeof(mac)); + else if (olen == 10 && odata[0] == 0 && odata[1] == 3) + memcpy(mac, &odata[4], sizeof(mac)); + } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) { + uint8_t fqdn_buf[256]; + memcpy(fqdn_buf, odata, olen); + fqdn_buf[olen++] = 0; + + if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0) + hostname_len = strcspn(hostname, "."); + } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) { + accept_reconf = true; + } + } + + if (!clid_data || !clid_len || clid_len > 130) + goto out; + + update(iface); + bool update_state = false; + + struct dhcpv6_assignment *first = NULL; + dhcpv6_for_each_option(start, end, otype, olen, odata) { + bool is_pd = (otype == DHCPV6_OPT_IA_PD); + bool is_na = (otype == DHCPV6_OPT_IA_NA); + if (!is_pd && !is_na) + continue; + + struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4]; + size_t ia_response_len = 0; + uint8_t reqlen = (is_pd) ? 62 : 128; + uint32_t reqhint = 0; + + // Parse request hint for IA-PD + if (is_pd) { + uint8_t *sdata; + uint16_t stype, slen; + dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) { + if (stype == DHCPV6_OPT_IA_PREFIX && slen >= sizeof(struct dhcpv6_ia_prefix) - 4) { + struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4]; + if (p->prefix) { + reqlen = p->prefix; + reqhint = ntohl(p->addr.s6_addr32[1]); + if (reqlen > 32 && reqlen <= 64) + reqhint &= (1U << (64 - reqlen)) - 1; + } + break; + } + } + + if (reqlen > 64) + reqlen = 64; + } + + // Find assignment + struct dhcpv6_assignment *c, *a = NULL; + list_for_each_entry(c, &iface->ia_assignments, head) { + if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) || + (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1] + && !memcmp(c->mac, mac, sizeof(mac)))) && + (c->iaid == ia->iaid || c->valid_until < now) && + ((is_pd && c->length <= 64) || (is_na && c->length == 128))) { + a = c; + + // Reset state + apply_lease(iface, a, false); + memcpy(a->clid_data, clid_data, clid_len); + a->clid_len = clid_len; + a->iaid = ia->iaid; + a->peer = *addr; + a->reconf_cnt = 0; + a->reconf_sent = 0; + break; + } + } + + // Generic message handling + uint16_t status = DHCPV6_STATUS_OK; + if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) { + bool assigned = !!a; + + if (!a && !iface->no_dynamic_dhcp) { // Create new binding + a = calloc(1, sizeof(*a) + clid_len); + a->clid_len = clid_len; + a->iaid = ia->iaid; + a->length = reqlen; + a->peer = *addr; + a->assigned = reqhint; + if (first) + memcpy(a->key, first->key, sizeof(a->key)); + else + odhcpd_urandom(a->key, sizeof(a->key)); + memcpy(a->clid_data, clid_data, clid_len); + + if (is_pd) + while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64); + else + assigned = assign_na(iface, a); + } + + if (!assigned || iface->ia_addr_len == 0) { // Set error status + status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL; + } else if (assigned && !first) { // + size_t handshake_len = 4; + buf[0] = 0; + buf[1] = DHCPV6_OPT_RECONF_ACCEPT; + buf[2] = 0; + buf[3] = 0; + + if (hdr->msg_type == DHCPV6_MSG_REQUEST) { + struct dhcpv6_auth_reconfigure auth = { + htons(DHCPV6_OPT_AUTH), + htons(sizeof(auth) - 4), + 3, 1, 0, + {htonl(time(NULL)), htonl(++serial)}, + 1, + {0} + }; + memcpy(auth.key, a->key, sizeof(a->key)); + memcpy(buf + handshake_len, &auth, sizeof(auth)); + handshake_len += sizeof(auth); + } + + buf += handshake_len; + buflen -= handshake_len; + response_len += handshake_len; + + first = a; + } + + ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true); + + // Was only a solicitation: mark binding for removal + if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) { + a->valid_until = 0; + } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) { + if (hostname_len > 0) { + a->hostname = realloc(a->hostname, hostname_len + 1); + memcpy(a->hostname, hostname, hostname_len); + a->hostname[hostname_len] = 0; + } + a->accept_reconf = accept_reconf; + apply_lease(iface, a, true); + update_state = true; + } else if (!assigned && a) { // Cleanup failed assignment + free(a->hostname); + free(a); + } + } else if (hdr->msg_type == DHCPV6_MSG_RENEW || + hdr->msg_type == DHCPV6_MSG_RELEASE || + hdr->msg_type == DHCPV6_MSG_REBIND || + hdr->msg_type == DHCPV6_MSG_DECLINE) { + if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) { + status = DHCPV6_STATUS_NOBINDING; + ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false); + } else if (hdr->msg_type == DHCPV6_MSG_RENEW || + hdr->msg_type == DHCPV6_MSG_REBIND) { + ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false); + if (a) + apply_lease(iface, a, true); + } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) { + a->valid_until = 0; + apply_lease(iface, a, false); + update_state = true; + } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) { + a->clid_len = 0; + a->valid_until = now + 3600; // Block address for 1h + update_state = true; + } + } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) { + // Always send NOTONLINK for CONFIRM so that clients restart connection + status = DHCPV6_STATUS_NOTONLINK; + ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true); + } + + buf += ia_response_len; + buflen -= ia_response_len; + response_len += ia_response_len; + } + + if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) { + buf[0] = 0; + buf[1] = DHCPV6_OPT_STATUS; + buf[2] = 0; + buf[3] = 2; + buf[4] = 0; + buf[5] = DHCPV6_STATUS_OK; + response_len += 6; + } + + if (update_state) + dhcpv6_write_statefile(); + +out: + return response_len; +} |