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- /**
- * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
- * Copyright (C) 2018 Hans Dedecker <dedeckeh@gmail.com>
- *
- * 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 <errno.h>
- #include <unistd.h>
- #include <stddef.h>
- #include <resolv.h>
- #include <sys/timerfd.h>
- #include <arpa/inet.h>
- #include <libubox/utils.h>
- #include "odhcpd.h"
- #include "dhcpv6.h"
- #ifdef DHCPV4_SUPPORT
- #include "dhcpv4.h"
- #endif
- static void relay_client_request(struct sockaddr_in6 *source,
- const void *data, size_t len, struct interface *iface);
- static void relay_server_response(uint8_t *data, size_t len);
- static void handle_dhcpv6(void *addr, void *data, size_t len,
- struct interface *iface, void *dest);
- static void handle_client_request(void *addr, void *data, size_t len,
- struct interface *iface, void *dest_addr);
- /* Create socket and register events */
- int dhcpv6_init(void)
- {
- return dhcpv6_ia_init();
- }
- int dhcpv6_setup_interface(struct interface *iface, bool enable)
- {
- int ret = 0;
- enable = enable && (iface->dhcpv6 != MODE_DISABLED);
- if (iface->dhcpv6_event.uloop.fd >= 0) {
- uloop_fd_delete(&iface->dhcpv6_event.uloop);
- close(iface->dhcpv6_event.uloop.fd);
- iface->dhcpv6_event.uloop.fd = -1;
- }
- /* Configure multicast settings */
- if (enable) {
- struct sockaddr_in6 bind_addr = {AF_INET6, htons(DHCPV6_SERVER_PORT),
- 0, IN6ADDR_ANY_INIT, 0};
- struct ipv6_mreq mreq;
- int val = 1;
- iface->dhcpv6_event.uloop.fd = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
- if (iface->dhcpv6_event.uloop.fd < 0) {
- syslog(LOG_ERR, "socket(AF_INET6): %m");
- ret = -1;
- goto out;
- }
- /* Basic IPv6 configuration */
- if (setsockopt(iface->dhcpv6_event.uloop.fd, SOL_SOCKET, SO_BINDTODEVICE,
- iface->ifname, strlen(iface->ifname)) < 0) {
- syslog(LOG_ERR, "setsockopt(SO_BINDTODEVICE): %m");
- ret = -1;
- goto out;
- }
- if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_V6ONLY,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IPV6_V6ONLY): %m");
- ret = -1;
- goto out;
- }
- if (setsockopt(iface->dhcpv6_event.uloop.fd, SOL_SOCKET, SO_REUSEADDR,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
- ret = -1;
- goto out;
- }
- if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IPV6_RECVPKTINFO): %m");
- ret = -1;
- goto out;
- }
- val = DHCPV6_HOP_COUNT_LIMIT;
- if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_HOPS): %m");
- ret = -1;
- goto out;
- }
- val = 0;
- if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IPV6_MULTICAST_LOOP): %m");
- ret = -1;
- goto out;
- }
- if (bind(iface->dhcpv6_event.uloop.fd, (struct sockaddr*)&bind_addr,
- sizeof(bind_addr)) < 0) {
- syslog(LOG_ERR, "bind(): %m");
- ret = -1;
- goto out;
- }
- memset(&mreq, 0, sizeof(mreq));
- inet_pton(AF_INET6, ALL_DHCPV6_RELAYS, &mreq.ipv6mr_multiaddr);
- mreq.ipv6mr_interface = iface->ifindex;
- if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP,
- &mreq, sizeof(mreq)) < 0) {
- syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m");
- ret = -1;
- goto out;
- }
- if (iface->dhcpv6 == MODE_SERVER) {
- memset(&mreq, 0, sizeof(mreq));
- inet_pton(AF_INET6, ALL_DHCPV6_SERVERS, &mreq.ipv6mr_multiaddr);
- mreq.ipv6mr_interface = iface->ifindex;
- if (setsockopt(iface->dhcpv6_event.uloop.fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP,
- &mreq, sizeof(mreq)) < 0) {
- syslog(LOG_ERR, "setsockopt(IPV6_ADD_MEMBERSHIP): %m");
- ret = -1;
- goto out;
- }
- }
- iface->dhcpv6_event.handle_dgram = handle_dhcpv6;
- odhcpd_register(&iface->dhcpv6_event);
- }
- ret = dhcpv6_ia_setup_interface(iface, enable);
- out:
- if (ret < 0 && iface->dhcpv6_event.uloop.fd >= 0) {
- close(iface->dhcpv6_event.uloop.fd);
- iface->dhcpv6_event.uloop.fd = -1;
- }
- return ret;
- }
- enum {
- IOV_NESTED = 0,
- IOV_DEST,
- IOV_MAXRT,
- #define IOV_STAT IOV_MAXRT
- IOV_RAPID_COMMIT,
- IOV_DNS,
- IOV_DNS_ADDR,
- IOV_SEARCH,
- IOV_SEARCH_DOMAIN,
- IOV_PDBUF,
- #define IOV_REFRESH IOV_PDBUF
- IOV_CERID,
- IOV_DHCPV6_RAW,
- IOV_NTP,
- IOV_NTP_ADDR,
- IOV_SNTP,
- IOV_SNTP_ADDR,
- IOV_RELAY_MSG,
- IOV_DHCPV4O6_SERVER,
- IOV_TOTAL
- };
- static void handle_nested_message(uint8_t *data, size_t len,
- struct dhcpv6_client_header **c_hdr, uint8_t **opts,
- uint8_t **end, struct iovec iov[IOV_TOTAL])
- {
- struct dhcpv6_relay_header *r_hdr = (struct dhcpv6_relay_header *)data;
- uint16_t otype, olen;
- uint8_t *odata;
- if (iov[IOV_NESTED].iov_base == NULL) {
- iov[IOV_NESTED].iov_base = data;
- iov[IOV_NESTED].iov_len = len;
- }
- if (len < sizeof(struct dhcpv6_client_header))
- return;
- if (r_hdr->msg_type != DHCPV6_MSG_RELAY_FORW) {
- iov[IOV_NESTED].iov_len = data - (uint8_t *)iov[IOV_NESTED].iov_base;
- *c_hdr = (void *)data;
- *opts = (uint8_t *)&(*c_hdr)[1];
- *end = data + len;
- return;
- }
- dhcpv6_for_each_option(r_hdr->options, data + len, otype, olen, odata) {
- if (otype == DHCPV6_OPT_RELAY_MSG) {
- iov[IOV_RELAY_MSG].iov_base = odata + olen;
- iov[IOV_RELAY_MSG].iov_len = (((uint8_t *)iov[IOV_NESTED].iov_base) +
- iov[IOV_NESTED].iov_len) - (odata + olen);
- handle_nested_message(odata, olen, c_hdr, opts, end, iov);
- return;
- }
- }
- }
- static void update_nested_message(uint8_t *data, size_t len, ssize_t pdiff)
- {
- struct dhcpv6_relay_header *hdr = (struct dhcpv6_relay_header*)data;
- if (hdr->msg_type != DHCPV6_MSG_RELAY_FORW)
- return;
- hdr->msg_type = DHCPV6_MSG_RELAY_REPL;
- uint16_t otype, olen;
- uint8_t *odata;
- dhcpv6_for_each_option(hdr->options, data + len, otype, olen, odata) {
- if (otype == DHCPV6_OPT_RELAY_MSG) {
- olen += pdiff;
- odata[-2] = (olen >> 8) & 0xff;
- odata[-1] = olen & 0xff;
- update_nested_message(odata, olen - pdiff, pdiff);
- return;
- }
- }
- }
- #ifdef DHCPV4_SUPPORT
- struct dhcpv4_msg_data {
- uint8_t *msg;
- size_t maxsize;
- ssize_t len;
- };
- static int send_reply(_unused const void *buf, size_t len,
- _unused const struct sockaddr *dest, _unused socklen_t dest_len,
- _unused void *opaque)
- {
- struct dhcpv4_msg_data *reply = opaque;
- if (len > reply->maxsize) {
- syslog(LOG_ERR, "4o6: reply too large, %zu > %zu", len, reply->maxsize);
- reply->len = -1;
- } else {
- memcpy(reply->msg, buf, len);
- reply->len = len;
- }
- return reply->len;
- }
- static ssize_t dhcpv6_4o6_query(uint8_t *buf, size_t buflen,
- struct interface *iface,
- const struct sockaddr_in6 *addr,
- const void *data, const uint8_t *end)
- {
- const struct dhcpv6_client_header *hdr = data;
- uint16_t otype, olen, msgv4_len = 0;
- uint8_t *msgv4_data = NULL;
- uint8_t *start = (uint8_t *)&hdr[1], *odata;
- struct sockaddr_in addrv4;
- struct dhcpv4_msg_data reply = { .msg = buf, .maxsize = buflen, .len = -1 };
- dhcpv6_for_each_option(start, end, otype, olen, odata) {
- if (otype == DHCPV6_OPT_DHCPV4_MSG) {
- msgv4_data = odata;
- msgv4_len = olen;
- }
- }
- if (!msgv4_data || msgv4_len == 0) {
- syslog(LOG_ERR, "4o6: missing DHCPv4 message option (%d)", DHCPV6_OPT_DHCPV4_MSG);
- return -1;
- }
- // Dummy IPv4 address
- memset(&addrv4, 0, sizeof(addrv4));
- addrv4.sin_family = AF_INET;
- addrv4.sin_addr.s_addr = INADDR_ANY;
- addrv4.sin_port = htons(DHCPV4_CLIENT_PORT);
- dhcpv4_handle_msg(&addrv4, msgv4_data, msgv4_len,
- iface, NULL, send_reply, &reply);
- return reply.len;
- }
- #endif /* DHCPV4_SUPPORT */
- /* Simple DHCPv6-server for information requests */
- static void handle_client_request(void *addr, void *data, size_t len,
- struct interface *iface, void *dest_addr)
- {
- struct dhcpv6_client_header *hdr = data;
- uint8_t *opts = (uint8_t *)&hdr[1], *opts_end = (uint8_t *)data + len;
- bool o_rapid_commit = false;
- if (len < sizeof(*hdr))
- return;
- syslog(LOG_DEBUG, "Got a DHCPv6-request on %s", iface->name);
- /* Construct reply message */
- struct __attribute__((packed)) {
- uint8_t msg_type;
- uint8_t tr_id[3];
- uint16_t serverid_type;
- uint16_t serverid_length;
- uint16_t duid_type;
- uint16_t hardware_type;
- uint8_t mac[6];
- uint16_t clientid_type;
- uint16_t clientid_length;
- uint8_t clientid_buf[130];
- } dest = {
- .msg_type = DHCPV6_MSG_REPLY,
- .serverid_type = htons(DHCPV6_OPT_SERVERID),
- .serverid_length = htons(10),
- .duid_type = htons(3),
- .hardware_type = htons(1),
- .clientid_type = htons(DHCPV6_OPT_CLIENTID),
- .clientid_buf = {0}
- };
- odhcpd_get_mac(iface, dest.mac);
- struct __attribute__((packed)) {
- uint16_t type;
- uint16_t len;
- uint32_t value;
- } maxrt = {htons(DHCPV6_OPT_SOL_MAX_RT), htons(sizeof(maxrt) - 4),
- htonl(60)};
- struct __attribute__((packed)) {
- uint16_t type;
- uint16_t len;
- } rapid_commit = {htons(DHCPV6_OPT_RAPID_COMMIT), 0};
- struct __attribute__((packed)) {
- uint16_t type;
- uint16_t len;
- uint16_t value;
- } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
- htons(DHCPV6_STATUS_USEMULTICAST)};
- struct __attribute__((packed)) {
- uint16_t type;
- uint16_t len;
- uint32_t value;
- } refresh = {htons(DHCPV6_OPT_INFO_REFRESH), htons(sizeof(uint32_t)),
- htonl(600)};
- struct in6_addr dns_addr, *dns_addr_ptr = iface->dns;
- size_t dns_cnt = iface->dns_cnt;
- if ((dns_cnt == 0) &&
- !odhcpd_get_interface_dns_addr(iface, &dns_addr)) {
- dns_addr_ptr = &dns_addr;
- dns_cnt = 1;
- }
- struct {
- uint16_t type;
- uint16_t len;
- } dns = {htons(DHCPV6_OPT_DNS_SERVERS), htons(dns_cnt * sizeof(*dns_addr_ptr))};
- /* SNTP */
- struct in6_addr *sntp_addr_ptr = iface->dhcpv6_sntp;
- size_t sntp_cnt = 0;
- struct {
- uint16_t type;
- uint16_t len;
- } dhcpv6_sntp;
- /* NTP */
- uint8_t *ntp_ptr = iface->dhcpv6_ntp;
- uint16_t ntp_len = iface->dhcpv6_ntp_len;
- size_t ntp_cnt = 0;
- struct {
- uint16_t type;
- uint16_t len;
- } ntp;
- uint16_t otype, olen;
- uint16_t *reqopts = NULL;
- uint8_t *odata;
- size_t reqopts_len = 0;
- dhcpv6_for_each_option(opts, opts_end, otype, olen, odata) {
- if (otype == DHCPV6_OPT_ORO) {
- reqopts_len = olen;
- reqopts = (uint16_t *)odata;
- }
- }
- for(size_t opt = 0; opt < reqopts_len/2; opt++) {
- if (iface->dhcpv6_sntp_cnt != 0 &&
- DHCPV6_OPT_SNTP_SERVERS == ntohs(reqopts[opt])) {
- sntp_cnt = iface->dhcpv6_sntp_cnt;
- dhcpv6_sntp.type = htons(DHCPV6_OPT_SNTP_SERVERS);
- dhcpv6_sntp.len = htons(sntp_cnt * sizeof(*sntp_addr_ptr));
- } else if (iface->dhcpv6_ntp_cnt != 0 &&
- DHCPV6_OPT_NTP_SERVERS == ntohs(reqopts[opt])) {
- ntp_cnt = iface->dhcpv6_ntp_cnt;
- ntp.type = htons(DHCPV6_OPT_NTP_SERVERS);
- ntp.len = htons(ntp_len);
- }
- }
- /* DNS Search options */
- uint8_t search_buf[256], *search_domain = iface->search;
- size_t search_len = iface->search_len;
- if (!search_domain && !res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
- int len = dn_comp(_res.dnsrch[0], search_buf,
- sizeof(search_buf), NULL, NULL);
- if (len > 0) {
- search_domain = search_buf;
- search_len = len;
- }
- }
- struct {
- uint16_t type;
- uint16_t len;
- } search = {htons(DHCPV6_OPT_DNS_DOMAIN), htons(search_len)};
- struct __attribute__((packed)) dhcpv4o6_server {
- uint16_t type;
- uint16_t len;
- struct in6_addr addr;
- } dhcpv4o6_server = {htons(DHCPV6_OPT_4O6_SERVER), htons(sizeof(struct in6_addr)),
- IN6ADDR_ANY_INIT};
- struct dhcpv6_cer_id cerid = {
- #ifdef EXT_CER_ID
- .type = htons(EXT_CER_ID),
- #endif
- .len = htons(36),
- .addr = iface->dhcpv6_pd_cer,
- };
- uint8_t pdbuf[512];
- struct iovec iov[IOV_TOTAL] = {
- [IOV_NESTED] = {NULL, 0},
- [IOV_DEST] = {&dest, (uint8_t*)&dest.clientid_type - (uint8_t*)&dest},
- [IOV_MAXRT] = {&maxrt, sizeof(maxrt)},
- [IOV_RAPID_COMMIT] = {&rapid_commit, 0},
- [IOV_DNS] = {&dns, (dns_cnt) ? sizeof(dns) : 0},
- [IOV_DNS_ADDR] = {dns_addr_ptr, dns_cnt * sizeof(*dns_addr_ptr)},
- [IOV_SEARCH] = {&search, (search_len) ? sizeof(search) : 0},
- [IOV_SEARCH_DOMAIN] = {search_domain, search_len},
- [IOV_PDBUF] = {pdbuf, 0},
- [IOV_CERID] = {&cerid, 0},
- [IOV_DHCPV6_RAW] = {iface->dhcpv6_raw, iface->dhcpv6_raw_len},
- [IOV_NTP] = {&ntp, (ntp_cnt) ? sizeof(ntp) : 0},
- [IOV_NTP_ADDR] = {ntp_ptr, (ntp_cnt) ? ntp_len : 0},
- [IOV_SNTP] = {&dhcpv6_sntp, (sntp_cnt) ? sizeof(dhcpv6_sntp) : 0},
- [IOV_SNTP_ADDR] = {sntp_addr_ptr, sntp_cnt * sizeof(*sntp_addr_ptr)},
- [IOV_RELAY_MSG] = {NULL, 0},
- [IOV_DHCPV4O6_SERVER] = {&dhcpv4o6_server, 0},
- };
- if (hdr->msg_type == DHCPV6_MSG_RELAY_FORW)
- handle_nested_message(data, len, &hdr, &opts, &opts_end, iov);
- switch (hdr->msg_type) {
- case DHCPV6_MSG_SOLICIT:
- case DHCPV6_MSG_REQUEST:
- case DHCPV6_MSG_CONFIRM:
- case DHCPV6_MSG_RENEW:
- case DHCPV6_MSG_REBIND:
- case DHCPV6_MSG_RELEASE:
- case DHCPV6_MSG_DECLINE:
- case DHCPV6_MSG_INFORMATION_REQUEST:
- case DHCPV6_MSG_RELAY_FORW:
- #ifdef DHCPV4_SUPPORT
- case DHCPV6_MSG_DHCPV4_QUERY:
- #endif
- break; /* Valid message types for clients */
- case DHCPV6_MSG_ADVERTISE:
- case DHCPV6_MSG_REPLY:
- case DHCPV6_MSG_RECONFIGURE:
- case DHCPV6_MSG_RELAY_REPL:
- case DHCPV6_MSG_DHCPV4_RESPONSE:
- #ifndef DHCPV4_SUPPORT
- case DHCPV6_MSG_DHCPV4_QUERY:
- #endif
- default:
- return; /* Invalid message types for clients */
- }
- if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 &&
- (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_CONFIRM ||
- hdr->msg_type == DHCPV6_MSG_REBIND || hdr->msg_type == DHCPV6_MSG_INFORMATION_REQUEST))
- return;
- memcpy(dest.tr_id, hdr->transaction_id, sizeof(dest.tr_id));
- /* Go through options and find what we need */
- dhcpv6_for_each_option(opts, opts_end, otype, olen, odata) {
- if (otype == DHCPV6_OPT_CLIENTID && olen <= 130) {
- dest.clientid_length = htons(olen);
- memcpy(dest.clientid_buf, odata, olen);
- iov[IOV_DEST].iov_len += 4 + olen;
- } else if (otype == DHCPV6_OPT_SERVERID) {
- if (olen != ntohs(dest.serverid_length) ||
- memcmp(odata, &dest.duid_type, olen))
- return; /* Not for us */
- } else if (iface->filter_class && otype == DHCPV6_OPT_USER_CLASS) {
- uint8_t *c = odata, *cend = &odata[olen];
- for (; &c[2] <= cend && &c[2 + (c[0] << 8) + c[1]] <= cend; c = &c[2 + (c[0] << 8) + c[1]]) {
- size_t elen = strlen(iface->filter_class);
- if (((((size_t)c[0]) << 8) | c[1]) == elen && !memcmp(&c[2], iface->filter_class, elen))
- return; /* Ignore from homenet */
- }
- } else if (otype == DHCPV6_OPT_IA_PD) {
- #ifdef EXT_CER_ID
- iov[IOV_CERID].iov_len = sizeof(cerid);
- if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)) {
- struct odhcpd_ipaddr *addrs;
- ssize_t len = netlink_get_interface_addrs(0, true, &addrs);
- for (ssize_t i = 0; i < len; ++i)
- if (IN6_IS_ADDR_UNSPECIFIED(&cerid.addr)
- || memcmp(&addrs[i].addr, &cerid.addr, sizeof(cerid.addr)) < 0)
- cerid.addr = addrs[i].addr.in6;
- free(addrs);
- }
- #endif
- } else if (otype == DHCPV6_OPT_RAPID_COMMIT && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
- iov[IOV_RAPID_COMMIT].iov_len = sizeof(rapid_commit);
- o_rapid_commit = true;
- } else if (otype == DHCPV6_OPT_ORO) {
- for (int i=0; i < olen/2; i++) {
- uint16_t option = ntohs(((uint16_t *)odata)[i]);
- switch (option) {
- #ifdef DHCPV4_SUPPORT
- case DHCPV6_OPT_4O6_SERVER:
- if (iface->dhcpv4) {
- /* According to RFC 7341, 7.2. DHCP 4o6 Server Address Option Format:
- * This option may also carry no IPv6 addresses, which instructs the
- * client to use the All_DHCP_Relay_Agents_and_Servers multicast address
- * as the destination address.
- *
- * The ISC dhclient logs a missing IPv6 address as an error but seems to
- * work anyway:
- * dhcp4-o-dhcp6-server: expecting at least 16 bytes; got 0
- *
- * Include the All_DHCP_Relay_Agents_and_Servers multicast address
- * to make it explicit which address to use. */
- struct dhcpv4o6_server *server = iov[IOV_DHCPV4O6_SERVER].iov_base;
- inet_pton(AF_INET6, ALL_DHCPV6_RELAYS, &server->addr);
- iov[IOV_DHCPV4O6_SERVER].iov_len = sizeof(dhcpv4o6_server);
- }
- break;
- #endif /* DHCPV4_SUPPORT */
- default:
- break;
- }
- }
- }
- }
- if (!IN6_IS_ADDR_MULTICAST((struct in6_addr *)dest_addr) && iov[IOV_NESTED].iov_len == 0 &&
- (hdr->msg_type == DHCPV6_MSG_REQUEST || hdr->msg_type == DHCPV6_MSG_RENEW ||
- hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE)) {
- iov[IOV_STAT].iov_base = &stat;
- iov[IOV_STAT].iov_len = sizeof(stat);
- for (ssize_t i = IOV_STAT + 1; i < IOV_TOTAL; ++i)
- iov[i].iov_len = 0;
- odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface);
- return;
- }
- if (hdr->msg_type == DHCPV6_MSG_SOLICIT && !o_rapid_commit) {
- dest.msg_type = DHCPV6_MSG_ADVERTISE;
- } else if (hdr->msg_type == DHCPV6_MSG_INFORMATION_REQUEST) {
- iov[IOV_REFRESH].iov_base = &refresh;
- iov[IOV_REFRESH].iov_len = sizeof(refresh);
- /* Return inf max rt option in reply to information request */
- maxrt.type = htons(DHCPV6_OPT_INF_MAX_RT);
- }
- #ifdef DHCPV4_SUPPORT
- if (hdr->msg_type == DHCPV6_MSG_DHCPV4_QUERY) {
- struct _packed dhcpv4_msg_data {
- uint16_t type;
- uint16_t len;
- uint8_t msg[1];
- } *msg_opt = (struct dhcpv4_msg_data*)pdbuf;
- ssize_t msglen;
- memset(pdbuf, 0, sizeof(pdbuf));
- msglen = dhcpv6_4o6_query(msg_opt->msg, sizeof(pdbuf) - sizeof(*msg_opt) + 1,
- iface, addr, (const void *)hdr, opts_end);
- if (msglen <= 0) {
- syslog(LOG_ERR, "4o6: query failed");
- return;
- }
- msg_opt->type = htons(DHCPV6_OPT_DHCPV4_MSG);
- msg_opt->len = htons(msglen);
- iov[IOV_PDBUF].iov_len = sizeof(*msg_opt) - 1 + msglen;
- dest.msg_type = DHCPV6_MSG_DHCPV4_RESPONSE;
- } else
- #endif /* DHCPV4_SUPPORT */
- if (hdr->msg_type != DHCPV6_MSG_INFORMATION_REQUEST) {
- ssize_t ialen = dhcpv6_ia_handle_IAs(pdbuf, sizeof(pdbuf), iface, addr, (const void *)hdr, opts_end);
- iov[IOV_PDBUF].iov_len = ialen;
- if (ialen < 0 ||
- (ialen == 0 && (hdr->msg_type == DHCPV6_MSG_REBIND || hdr->msg_type == DHCPV6_MSG_CONFIRM)))
- return;
- }
- if (iov[IOV_NESTED].iov_len > 0) /* Update length */
- update_nested_message(data, len, iov[IOV_DEST].iov_len + iov[IOV_MAXRT].iov_len +
- iov[IOV_RAPID_COMMIT].iov_len + iov[IOV_DNS].iov_len +
- iov[IOV_DNS_ADDR].iov_len + iov[IOV_SEARCH].iov_len +
- iov[IOV_SEARCH_DOMAIN].iov_len + iov[IOV_PDBUF].iov_len +
- iov[IOV_DHCPV4O6_SERVER].iov_len +
- iov[IOV_CERID].iov_len + iov[IOV_DHCPV6_RAW].iov_len +
- iov[IOV_NTP].iov_len + iov[IOV_NTP_ADDR].iov_len +
- iov[IOV_SNTP].iov_len + iov[IOV_SNTP_ADDR].iov_len -
- (4 + opts_end - opts));
- syslog(LOG_DEBUG, "Sending a DHCPv6-%s on %s", iov[IOV_NESTED].iov_len ? "relay-reply" : "reply", iface->name);
- odhcpd_send(iface->dhcpv6_event.uloop.fd, addr, iov, ARRAY_SIZE(iov), iface);
- }
- /* Central DHCPv6-relay handler */
- static void handle_dhcpv6(void *addr, void *data, size_t len,
- struct interface *iface, void *dest_addr)
- {
- if (iface->dhcpv6 == MODE_SERVER) {
- handle_client_request(addr, data, len, iface, dest_addr);
- } else if (iface->dhcpv6 == MODE_RELAY) {
- if (iface->master)
- relay_server_response(data, len);
- else
- relay_client_request(addr, data, len, iface);
- }
- }
- /* Relay server response (regular relay server handling) */
- static void relay_server_response(uint8_t *data, size_t len)
- {
- /* Information we need to gather */
- uint8_t *payload_data = NULL;
- size_t payload_len = 0;
- int32_t ifaceidx = 0;
- struct sockaddr_in6 target = {AF_INET6, htons(DHCPV6_CLIENT_PORT),
- 0, IN6ADDR_ANY_INIT, 0};
- int otype, olen;
- uint8_t *odata, *end = data + len;
- /* Relay DHCPv6 reply from server to client */
- struct dhcpv6_relay_header *h = (void*)data;
- syslog(LOG_DEBUG, "Got a DHCPv6-relay-reply");
- if (len < sizeof(*h) || h->msg_type != DHCPV6_MSG_RELAY_REPL)
- return;
- memcpy(&target.sin6_addr, &h->peer_address, sizeof(struct in6_addr));
- /* Go through options and find what we need */
- dhcpv6_for_each_option(h->options, end, otype, olen, odata) {
- if (otype == DHCPV6_OPT_INTERFACE_ID
- && olen == sizeof(ifaceidx)) {
- memcpy(&ifaceidx, odata, sizeof(ifaceidx));
- } else if (otype == DHCPV6_OPT_RELAY_MSG) {
- payload_data = odata;
- payload_len = olen;
- }
- }
- /* Invalid interface-id or basic payload */
- struct interface *iface = odhcpd_get_interface_by_index(ifaceidx);
- if (!iface || iface->master || !payload_data || payload_len < 4)
- return;
- bool is_authenticated = false;
- struct in6_addr *dns_ptr = NULL;
- size_t dns_count = 0;
- /* If the payload is relay-reply we have to send to the server port */
- if (payload_data[0] == DHCPV6_MSG_RELAY_REPL) {
- target.sin6_port = htons(DHCPV6_SERVER_PORT);
- } else { /* Go through the payload data */
- struct dhcpv6_client_header *h = (void*)payload_data;
- end = payload_data + payload_len;
- dhcpv6_for_each_option(&h[1], end, otype, olen, odata) {
- if (otype == DHCPV6_OPT_DNS_SERVERS && olen >= 16) {
- dns_ptr = (struct in6_addr*)odata;
- dns_count = olen / 16;
- } else if (otype == DHCPV6_OPT_AUTH) {
- is_authenticated = true;
- }
- }
- }
- /* Rewrite DNS servers if requested */
- if (iface->always_rewrite_dns && dns_ptr && dns_count > 0) {
- if (is_authenticated)
- return; /* Impossible to rewrite */
- const struct in6_addr *rewrite = iface->dns;
- struct in6_addr addr;
- size_t rewrite_cnt = iface->dns_cnt;
- if (rewrite_cnt == 0) {
- if (odhcpd_get_interface_dns_addr(iface, &addr))
- return; /* Unable to get interface address */
- rewrite = &addr;
- rewrite_cnt = 1;
- }
- /* Copy over any other addresses */
- for (size_t i = 0; i < dns_count; ++i) {
- size_t j = (i < rewrite_cnt) ? i : rewrite_cnt - 1;
- memcpy(&dns_ptr[i], &rewrite[j], sizeof(*rewrite));
- }
- }
- struct iovec iov = {payload_data, payload_len};
- syslog(LOG_DEBUG, "Sending a DHCPv6-reply on %s", iface->name);
- odhcpd_send(iface->dhcpv6_event.uloop.fd, &target, &iov, 1, iface);
- }
- static struct odhcpd_ipaddr *relay_link_address(struct interface *iface)
- {
- struct odhcpd_ipaddr *addr = NULL;
- time_t now = odhcpd_time();
- for (size_t i = 0; i < iface->addr6_len; i++) {
- if (iface->addr6[i].valid_lt <= (uint32_t)now)
- continue;
- if (iface->addr6[i].preferred_lt > (uint32_t)now) {
- addr = &iface->addr6[i];
- break;
- }
- if (!addr || (iface->addr6[i].valid_lt > addr->valid_lt))
- addr = &iface->addr6[i];
- }
- return addr;
- }
- /* Relay client request (regular DHCPv6-relay) */
- static void relay_client_request(struct sockaddr_in6 *source,
- const void *data, size_t len, struct interface *iface)
- {
- const struct dhcpv6_relay_header *h = data;
- /* Construct our forwarding envelope */
- struct dhcpv6_relay_forward_envelope hdr = {
- .msg_type = DHCPV6_MSG_RELAY_FORW,
- .hop_count = 0,
- .interface_id_type = htons(DHCPV6_OPT_INTERFACE_ID),
- .interface_id_len = htons(sizeof(uint32_t)),
- .relay_message_type = htons(DHCPV6_OPT_RELAY_MSG),
- .relay_message_len = htons(len),
- };
- struct iovec iov[2] = {{&hdr, sizeof(hdr)}, {(void *)data, len}};
- struct interface *c;
- struct odhcpd_ipaddr *ip;
- struct sockaddr_in6 s;
- if (h->msg_type == DHCPV6_MSG_RELAY_REPL ||
- h->msg_type == DHCPV6_MSG_RECONFIGURE ||
- h->msg_type == DHCPV6_MSG_REPLY ||
- h->msg_type == DHCPV6_MSG_ADVERTISE)
- return; /* Invalid message types for client */
- syslog(LOG_DEBUG, "Got a DHCPv6-request on %s", iface->name);
- if (h->msg_type == DHCPV6_MSG_RELAY_FORW) { /* handle relay-forward */
- if (h->hop_count >= DHCPV6_HOP_COUNT_LIMIT)
- return; /* Invalid hop count */
- hdr.hop_count = h->hop_count + 1;
- }
- /* use memcpy here as the destination fields are unaligned */
- memcpy(&hdr.peer_address, &source->sin6_addr, sizeof(struct in6_addr));
- memcpy(&hdr.interface_id_data, &iface->ifindex, sizeof(iface->ifindex));
- /* Detect public IP of slave interface to use as link-address */
- ip = relay_link_address(iface);
- if (ip)
- memcpy(&hdr.link_address, &ip->addr.in6, sizeof(hdr.link_address));
- memset(&s, 0, sizeof(s));
- s.sin6_family = AF_INET6;
- s.sin6_port = htons(DHCPV6_SERVER_PORT);
- inet_pton(AF_INET6, ALL_DHCPV6_SERVERS, &s.sin6_addr);
- avl_for_each_element(&interfaces, c, avl) {
- if (!c->master || c->dhcpv6 != MODE_RELAY)
- continue;
- if (!ip) {
- /* No suitable address! Is the slave not configured yet?
- * Detect public IP of master interface and use it instead
- * This is WRONG and probably violates the RFC. However
- * otherwise we have a hen and egg problem because the
- * slave-interface cannot be auto-configured. */
- ip = relay_link_address(c);
- if (!ip)
- continue; /* Could not obtain a suitable address */
- memcpy(&hdr.link_address, &ip->addr.in6, sizeof(hdr.link_address));
- ip = NULL;
- }
- syslog(LOG_DEBUG, "Sending a DHCPv6-relay-forward on %s", c->name);
- odhcpd_send(c->dhcpv6_event.uloop.fd, &s, iov, 2, c);
- }
- }
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