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- /**
- * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
- * Copyright (C) 2016 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 <time.h>
- #include <errno.h>
- #include <fcntl.h>
- #include <unistd.h>
- #include <stddef.h>
- #include <stdlib.h>
- #include <resolv.h>
- #include <limits.h>
- #include <net/if.h>
- #include <net/if_arp.h>
- #include <netinet/ip.h>
- #include <sys/ioctl.h>
- #include <sys/timerfd.h>
- #include <arpa/inet.h>
- #include <libubox/md5.h>
- #include "odhcpd.h"
- #include "dhcpv4.h"
- #include "dhcpv6.h"
- static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info);
- static int setup_dhcpv4_addresses(struct interface *iface);
- static void update_static_assignments(struct interface *iface);
- static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr);
- static void valid_until_cb(struct uloop_timeout *event);
- static void handle_addrlist_change(struct interface *iface);
- static void free_dhcpv4_assignment(struct dhcpv4_assignment *a);
- static void dhcpv4_fr_start(struct dhcpv4_assignment *a);
- static void dhcpv4_fr_rand_delay(struct dhcpv4_assignment *a);
- static void dhcpv4_fr_stop(struct dhcpv4_assignment *a);
- static void handle_dhcpv4(void *addr, void *data, size_t len,
- struct interface *iface, void *dest_addr);
- static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
- enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
- uint32_t *leasetime, const char *hostname, const size_t hostname_len,
- const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid);
- static struct netevent_handler dhcpv4_netevent_handler = { .cb = dhcpv4_netevent_cb, };
- static struct uloop_timeout valid_until_timeout = {.cb = valid_until_cb};
- static uint32_t serial = 0;
- struct odhcpd_ref_ip {
- struct list_head head;
- int ref_cnt;
- struct odhcpd_ipaddr addr;
- };
- /* Create socket and register events */
- int dhcpv4_init(void)
- {
- uloop_timeout_set(&valid_until_timeout, 1000);
- netlink_add_netevent_handler(&dhcpv4_netevent_handler);
- return 0;
- }
- int dhcpv4_setup_interface(struct interface *iface, bool enable)
- {
- int ret = 0;
- if (iface->dhcpv4_event.uloop.fd > 0) {
- uloop_fd_delete(&iface->dhcpv4_event.uloop);
- close(iface->dhcpv4_event.uloop.fd);
- iface->dhcpv4_event.uloop.fd = -1;
- }
- if (iface->dhcpv4 && enable) {
- struct sockaddr_in bind_addr = {AF_INET, htons(DHCPV4_SERVER_PORT),
- {INADDR_ANY}, {0}};
- int val = 1;
- if (!iface->dhcpv4_assignments.next)
- INIT_LIST_HEAD(&iface->dhcpv4_assignments);
- if (!iface->dhcpv4_fr_ips.next)
- INIT_LIST_HEAD(&iface->dhcpv4_fr_ips);
- iface->dhcpv4_event.uloop.fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
- if (iface->dhcpv4_event.uloop.fd < 0) {
- syslog(LOG_ERR, "socket(AF_INET): %m");
- ret = -1;
- goto out;
- }
- /* Basic IPv4 configuration */
- if (setsockopt(iface->dhcpv4_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->dhcpv4_event.uloop.fd, SOL_SOCKET, SO_BROADCAST,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(SO_BROADCAST): %m");
- ret = -1;
- goto out;
- }
- if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_PKTINFO,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IP_PKTINFO): %m");
- ret = -1;
- goto out;
- }
- val = IPTOS_PREC_INTERNETCONTROL;
- if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_TOS,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IP_TOS): %m");
- ret = -1;
- goto out;
- }
- val = IP_PMTUDISC_DONT;
- if (setsockopt(iface->dhcpv4_event.uloop.fd, IPPROTO_IP, IP_MTU_DISCOVER,
- &val, sizeof(val)) < 0) {
- syslog(LOG_ERR, "setsockopt(IP_MTU_DISCOVER): %m");
- ret = -1;
- goto out;
- }
- if (setsockopt(iface->dhcpv4_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 (bind(iface->dhcpv4_event.uloop.fd, (struct sockaddr*)&bind_addr,
- sizeof(bind_addr)) < 0) {
- syslog(LOG_ERR, "bind(): %m");
- ret = -1;
- goto out;
- }
- if (setup_dhcpv4_addresses(iface) < 0) {
- ret = -1;
- goto out;
- }
- iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
- odhcpd_register(&iface->dhcpv4_event);
- update_static_assignments(iface);
- } else if (iface->dhcpv4_assignments.next) {
- while (!list_empty(&iface->dhcpv4_assignments))
- free_dhcpv4_assignment(list_first_entry(&iface->dhcpv4_assignments,
- struct dhcpv4_assignment, head));
- }
- out:
- if (ret < 0 && iface->dhcpv4_event.uloop.fd > 0) {
- close(iface->dhcpv4_event.uloop.fd);
- iface->dhcpv4_event.uloop.fd = -1;
- }
- return ret;
- }
- static void dhcpv4_netevent_cb(unsigned long event, struct netevent_handler_info *info)
- {
- struct interface *iface = info->iface;
- if (!iface || iface->dhcpv4 == MODE_DISABLED)
- return;
- switch (event) {
- case NETEV_IFINDEX_CHANGE:
- dhcpv4_setup_interface(iface, true);
- break;
- case NETEV_ADDRLIST_CHANGE:
- handle_addrlist_change(iface);
- break;
- default:
- break;
- }
- }
- static struct dhcpv4_assignment *find_assignment_by_hwaddr(struct interface *iface, const uint8_t *hwaddr)
- {
- struct dhcpv4_assignment *a;
- list_for_each_entry(a, &iface->dhcpv4_assignments, head)
- if (!memcmp(a->hwaddr, hwaddr, 6))
- return a;
- return NULL;
- }
- static struct dhcpv4_assignment *find_assignment_by_addr(struct interface *iface, const uint32_t addr)
- {
- struct dhcpv4_assignment *a;
- list_for_each_entry(a, &iface->dhcpv4_assignments, head)
- if (a->addr == addr)
- return a;
- return NULL;
- }
- static int setup_dhcpv4_addresses(struct interface *iface)
- {
- iface->dhcpv4_start_ip.s_addr = INADDR_ANY;
- iface->dhcpv4_end_ip.s_addr = INADDR_ANY;
- iface->dhcpv4_local.s_addr = INADDR_ANY;
- iface->dhcpv4_bcast.s_addr = INADDR_ANY;
- iface->dhcpv4_mask.s_addr = INADDR_ANY;
- /* Sanity checks */
- if (iface->dhcpv4_start.s_addr & htonl(0xffff0000) ||
- iface->dhcpv4_end.s_addr & htonl(0xffff0000) ||
- ntohl(iface->dhcpv4_start.s_addr) > ntohl(iface->dhcpv4_end.s_addr)) {
- syslog(LOG_ERR, "Invalid DHCP range for %s", iface->name);
- return -1;
- }
- if (!iface->addr4_len) {
- syslog(LOG_WARNING, "No network(s) available on %s", iface->name);
- return -1;
- }
- uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
- uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
- for (size_t i = 0; i < iface->addr4_len && start && end; i++) {
- struct in_addr *addr = &iface->addr4[i].addr.in;
- struct in_addr mask;
- if (addr_is_fr_ip(iface, addr))
- continue;
- odhcpd_bitlen2netmask(false, iface->addr4[i].prefix, &mask);
- if ((start & ntohl(~mask.s_addr)) == start &&
- (end & ntohl(~mask.s_addr)) == end) {
- iface->dhcpv4_start_ip.s_addr = htonl(start) |
- (addr->s_addr & mask.s_addr);
- iface->dhcpv4_end_ip.s_addr = htonl(end) |
- (addr->s_addr & mask.s_addr);
- iface->dhcpv4_local = *addr;
- iface->dhcpv4_bcast = iface->addr4[i].broadcast;
- iface->dhcpv4_mask = mask;
- return 0;
- }
- }
- /* Don't allocate IP range for subnets bigger than 28 */
- if (iface->addr4[0].prefix > 28) {
- syslog(LOG_WARNING, "Auto allocation of DHCP range fails on %s", iface->name);
- return -1;
- }
- iface->dhcpv4_local = iface->addr4[0].addr.in;
- iface->dhcpv4_bcast = iface->addr4[0].broadcast;
- odhcpd_bitlen2netmask(false, iface->addr4[0].prefix, &iface->dhcpv4_mask);
- end = start = iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr;
- /* Auto allocate ranges */
- if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffff00) {
- iface->dhcpv4_start_ip.s_addr = start | htonl(100);
- iface->dhcpv4_end_ip.s_addr = end | htonl(250);
- } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffc0) {
- iface->dhcpv4_start_ip.s_addr = start | htonl(10);
- iface->dhcpv4_end_ip.s_addr = end | htonl(60);
- } else if (ntohl(iface->dhcpv4_mask.s_addr) <= 0xffffffe0) {
- iface->dhcpv4_start_ip.s_addr = start | htonl(10);
- iface->dhcpv4_end_ip.s_addr = end | htonl(30);
- } else {
- iface->dhcpv4_start_ip.s_addr = start | htonl(3);
- iface->dhcpv4_end_ip.s_addr = end | htonl(12);
- }
- return 0;
- }
- static void update_static_assignments(struct interface *iface)
- {
- struct dhcpv4_assignment *a, *c;
- /* Cleanup static entries not belonging to the network */
- list_for_each_entry_safe(a, c, &iface->dhcpv4_assignments, head) {
- if ((a->flags & OAF_STATIC) &&
- ((a->addr & iface->dhcpv4_mask.s_addr) !=
- (iface->dhcpv4_start.s_addr & iface->dhcpv4_mask.s_addr)))
- free_dhcpv4_assignment(a);
- }
- /* Parse static entries */
- struct lease *lease;
- list_for_each_entry(lease, &leases, head) {
- if ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
- (lease->ipaddr.s_addr & iface->dhcpv4_mask.s_addr)) {
- continue;
- }
- a = find_assignment_by_hwaddr(iface, lease->mac.ether_addr_octet);
- if (!a) {
- /* Check if there's an assignment with the specified IP address */
- if (find_assignment_by_addr(iface, lease->ipaddr.s_addr))
- continue;
- /* Construct entry */
- a = calloc(1, sizeof(*a));
- if (!a) {
- syslog(LOG_ERR, "Calloc failed for static lease on %s", iface->name);
- continue;
- }
- memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
- }
- a->leasetime = lease->dhcpv4_leasetime;
- a->addr = lease->ipaddr.s_addr;
- /* Static assignment */
- a->flags |= OAF_STATIC;
- /* Infinite valid */
- a->valid_until = 0;
- a->iface = iface;
- if (lease->hostname[0]) {
- free(a->hostname);
- a->hostname = strdup(lease->hostname);
- }
- /* Assign to all interfaces */
- list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
- if (ntohl(c->addr) > ntohl(a->addr)) {
- list_add_tail(&a->head, &c->head);
- break;
- }
- }
- if (&c->head == &iface->dhcpv4_assignments)
- list_add(&a->head, &iface->dhcpv4_assignments);
- }
- }
- static void inc_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct odhcpd_ref_ip *ip)
- {
- *ptr = ip;
- ip->ref_cnt++;
- }
- static void decr_ref_cnt_ip(struct odhcpd_ref_ip **ptr, struct interface *iface)
- {
- struct odhcpd_ref_ip *ip = *ptr;
- if (--ip->ref_cnt == 0) {
- netlink_setup_addr(&ip->addr, iface->ifindex, false, false);
- list_del(&ip->head);
- free(ip);
- }
- *ptr = NULL;
- }
- static bool addr_is_fr_ip(struct interface *iface, struct in_addr *addr)
- {
- struct odhcpd_ref_ip *p;
- list_for_each_entry(p, &iface->dhcpv4_fr_ips, head) {
- if (addr->s_addr == p->addr.addr.in.s_addr)
- return true;
- }
- return false;
- }
- static bool leases_require_fr(struct interface *iface, struct odhcpd_ipaddr *addr,
- uint32_t mask)
- {
- struct dhcpv4_assignment *a = NULL;
- struct odhcpd_ref_ip *fr_ip = NULL;
- list_for_each_entry(a, &iface->dhcpv4_assignments, head) {
- if ((a->accept_fr_nonce || iface->dhcpv4_forcereconf) &&
- !a->fr_ip &&
- ((a->addr & mask) == (addr->addr.in.s_addr & mask))) {
- if (!fr_ip) {
- fr_ip = calloc(1, sizeof(*fr_ip));
- if (!fr_ip)
- break;
- list_add(&fr_ip->head, &iface->dhcpv4_fr_ips);
- fr_ip->addr = *addr;
- }
- inc_ref_cnt_ip(&a->fr_ip, fr_ip);
- }
- }
- return fr_ip ? true : false;
- }
- static void valid_until_cb(struct uloop_timeout *event)
- {
- struct interface *iface;
- time_t now = odhcpd_time();
- avl_for_each_element(&interfaces, iface, avl) {
- if (iface->dhcpv4 != MODE_SERVER || iface->dhcpv4_assignments.next == NULL)
- continue;
- struct dhcpv4_assignment *a, *n;
- list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
- if (!INFINITE_VALID(a->valid_until) && a->valid_until < now)
- free_dhcpv4_assignment(a);
- }
- }
- uloop_timeout_set(event, 1000);
- }
- static void handle_addrlist_change(struct interface *iface)
- {
- struct odhcpd_ipaddr ip;
- struct odhcpd_ref_ip *a;
- struct dhcpv4_assignment *c;
- uint32_t mask = iface->dhcpv4_mask.s_addr;
- memset(&ip, 0, sizeof(ip));
- ip.addr.in = iface->dhcpv4_local;
- ip.prefix = odhcpd_netmask2bitlen(false, &iface->dhcpv4_mask);
- ip.broadcast = iface->dhcpv4_bcast;
- setup_dhcpv4_addresses(iface);
- if ((ip.addr.in.s_addr & mask) ==
- (iface->dhcpv4_local.s_addr & iface->dhcpv4_mask.s_addr))
- return;
- if (ip.addr.in.s_addr && !leases_require_fr(iface, &ip, mask))
- return;
- if (iface->dhcpv4_local.s_addr == INADDR_ANY || list_empty(&iface->dhcpv4_fr_ips))
- return;
- a = list_first_entry(&iface->dhcpv4_fr_ips, struct odhcpd_ref_ip, head);
- if (netlink_setup_addr(&a->addr, iface->ifindex, false, true)) {
- syslog(LOG_ERR, "Failed to add ip address on %s", iface->name);
- return;
- }
- list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
- if ((c->flags & OAF_BOUND) && c->fr_ip && !c->fr_cnt) {
- if (c->accept_fr_nonce || iface->dhcpv4_forcereconf)
- dhcpv4_fr_rand_delay(c);
- else
- dhcpv4_fr_stop(c);
- }
- }
- }
- static char *dhcpv4_msg_to_string(uint8_t reqmsg)
- {
- switch (reqmsg) {
- case (DHCPV4_MSG_DISCOVER):
- return "DHCPV4_MSG_DISCOVER";
- case (DHCPV4_MSG_OFFER):
- return "DHCPV4_MSG_OFFER";
- case (DHCPV4_MSG_REQUEST):
- return "DHCPV4_MSG_REQUEST";
- case (DHCPV4_MSG_DECLINE):
- return "DHCPV4_MSG_DECLINE";
- case (DHCPV4_MSG_ACK):
- return "DHCPV4_MSG_ACK";
- case (DHCPV4_MSG_NAK):
- return "DHCPV4_MSG_NAK";
- case (DHCPV4_MSG_RELEASE):
- return "DHCPV4_MSG_RELEASE";
- case (DHCPV4_MSG_INFORM):
- return "DHCPV4_MSG_INFORM";
- case (DHCPV4_MSG_FORCERENEW):
- return "DHCPV4_MSG_FORCERENEW";
- default:
- return "UNKNOWN";
- }
- }
- static void free_dhcpv4_assignment(struct dhcpv4_assignment *a)
- {
- if (a->head.next)
- list_del(&a->head);
- if (a->fr_ip)
- dhcpv4_fr_stop(a);
- free(a->hostname);
- free(a);
- }
- static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
- uint8_t type, uint8_t len, const void *data)
- {
- uint8_t *c = *cookie;
- uint8_t *end = (uint8_t *)msg + sizeof(*msg);
- if (*cookie + 2 + len > end)
- return;
- *c++ = type;
- *c++ = len;
- memcpy(c, data, len);
- *cookie = c + len;
- }
- static void dhcpv4_fr_send(struct dhcpv4_assignment *a)
- {
- struct dhcpv4_message fr_msg = {
- .op = DHCPV4_BOOTREPLY,
- .htype = 1,
- .hlen = 6,
- .hops = 0,
- .secs = 0,
- .flags = 0,
- .ciaddr = {INADDR_ANY},
- .yiaddr = {INADDR_ANY},
- .siaddr = {INADDR_ANY},
- .giaddr = {INADDR_ANY},
- .chaddr = {0},
- .sname = {0},
- .file = {0},
- };
- struct dhcpv4_auth_forcerenew *auth_o, auth = {
- .protocol = 3,
- .algorithm = 1,
- .rdm = 0,
- .replay = {htonl(time(NULL)), htonl(++serial)},
- .type = 2,
- .key = {0},
- };
- struct interface *iface = a->iface;
- odhcpd_urandom(&fr_msg.xid, sizeof(fr_msg.xid));
- memcpy(fr_msg.chaddr, a->hwaddr, fr_msg.hlen);
- fr_msg.options[0] = 0x63;
- fr_msg.options[1] = 0x82;
- fr_msg.options[2] = 0x53;
- fr_msg.options[3] = 0x63;
- uint8_t *cookie = &fr_msg.options[4];
- uint8_t msg = DHCPV4_MSG_FORCERENEW;
- dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
- if (a->accept_fr_nonce) {
- dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
- auth_o = (struct dhcpv4_auth_forcerenew *)(cookie - sizeof(auth));
- dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
- md5_ctx_t md5;
- uint8_t secretbytes[64];
- memset(secretbytes, 0, sizeof(secretbytes));
- memcpy(secretbytes, a->key, sizeof(a->key));
- for (size_t i = 0; i < sizeof(secretbytes); ++i)
- secretbytes[i] ^= 0x36;
- md5_begin(&md5);
- md5_hash(secretbytes, sizeof(secretbytes), &md5);
- md5_hash(&fr_msg, sizeof(fr_msg), &md5);
- md5_end(auth_o->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(auth_o->key, sizeof(auth_o->key), &md5);
- md5_end(auth_o->key, &md5);
- } else {
- dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_SERVERID, 4,
- &a->fr_ip->addr.addr.in.s_addr);
- dhcpv4_put(&fr_msg, &cookie, DHCPV4_OPT_END, 0, NULL);
- }
- struct sockaddr_in dest;
- memset(&dest, 0, sizeof(dest));
- dest.sin_family = AF_INET;
- dest.sin_port = htons(DHCPV4_CLIENT_PORT);
- dest.sin_addr.s_addr = a->addr;
- if (sendto(iface->dhcpv4_event.uloop.fd, &fr_msg, sizeof(fr_msg),
- MSG_DONTWAIT, (struct sockaddr*)&dest, sizeof(dest)) < 0)
- syslog(LOG_ERR, "Failed to send %s to %s - %s: %m", dhcpv4_msg_to_string(msg),
- odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
- else
- syslog(LOG_WARNING, "Sent %s to %s - %s", dhcpv4_msg_to_string(msg),
- odhcpd_print_mac(a->hwaddr, sizeof(a->hwaddr)), inet_ntoa(dest.sin_addr));
- }
- static void dhcpv4_fr_timer(struct uloop_timeout *event)
- {
- struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
- if (a->fr_cnt > 0 && a->fr_cnt < 8) {
- dhcpv4_fr_send(a);
- uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
- a->fr_cnt++;
- } else
- dhcpv4_fr_stop(a);
- }
- static void dhcpv4_fr_start(struct dhcpv4_assignment *a)
- {
- uloop_timeout_set(&a->fr_timer, 1000 << a->fr_cnt);
- a->fr_timer.cb = dhcpv4_fr_timer;
- a->fr_cnt++;
- dhcpv4_fr_send(a);
- }
- static void dhcpv4_fr_delay_timer(struct uloop_timeout *event)
- {
- struct dhcpv4_assignment *a = container_of(event, struct dhcpv4_assignment, fr_timer);
- struct interface *iface = a->iface;
- (iface->dhcpv4_event.uloop.fd == -1 ? dhcpv4_fr_rand_delay(a) : dhcpv4_fr_start(a));
- }
- static void dhcpv4_fr_rand_delay(struct dhcpv4_assignment *a)
- {
- #define MIN_DELAY 500
- #define MAX_FUZZ 500
- int msecs;
- odhcpd_urandom(&msecs, sizeof(msecs));
- msecs = labs(msecs)%MAX_FUZZ + MIN_DELAY;
- uloop_timeout_set(&a->fr_timer, msecs);
- a->fr_timer.cb = dhcpv4_fr_delay_timer;
- }
- static void dhcpv4_fr_stop(struct dhcpv4_assignment *a)
- {
- uloop_timeout_cancel(&a->fr_timer);
- decr_ref_cnt_ip(&a->fr_ip, a->iface);
- a->fr_cnt = 0;
- a->fr_timer.cb = NULL;
- }
- /* Handler for DHCPv4 messages */
- static void handle_dhcpv4(void *addr, void *data, size_t len,
- struct interface *iface, _unused void *dest_addr)
- {
- if (!iface->dhcpv4)
- return;
- struct dhcpv4_message *req = data;
- if (len < offsetof(struct dhcpv4_message, options) + 4 ||
- req->op != DHCPV4_BOOTREQUEST || req->hlen != 6)
- return;
- syslog(LOG_NOTICE, "Got DHCPv4 request on %s", iface->name);
- if (!iface->dhcpv4_start_ip.s_addr && !iface->dhcpv4_end_ip.s_addr) {
- syslog(LOG_WARNING, "No DHCP range available on %s", iface->name);
- return;
- }
- int sock = iface->dhcpv4_event.uloop.fd;
- struct dhcpv4_message reply = {
- .op = DHCPV4_BOOTREPLY,
- .htype = req->htype,
- .hlen = req->hlen,
- .hops = 0,
- .xid = req->xid,
- .secs = 0,
- .flags = req->flags,
- .ciaddr = {INADDR_ANY},
- .giaddr = req->giaddr,
- .siaddr = iface->dhcpv4_local,
- };
- memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
- reply.options[0] = 0x63;
- reply.options[1] = 0x82;
- reply.options[2] = 0x53;
- reply.options[3] = 0x63;
- uint8_t *cookie = &reply.options[4];
- uint8_t reqmsg = DHCPV4_MSG_REQUEST;
- uint8_t msg = DHCPV4_MSG_ACK;
- uint32_t reqaddr = INADDR_ANY;
- uint32_t leasetime = 0;
- size_t hostname_len = 0;
- char hostname[256];
- bool accept_fr_nonce = false;
- bool incl_fr_opt = false;
- uint8_t *start = &req->options[4];
- uint8_t *end = ((uint8_t*)data) + len;
- struct dhcpv4_option *opt;
- dhcpv4_for_each_option(start, end, opt) {
- if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
- reqmsg = opt->data[0];
- else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
- hostname_len = opt->len;
- memcpy(hostname, opt->data, hostname_len);
- hostname[hostname_len] = 0;
- } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4)
- memcpy(&reqaddr, opt->data, 4);
- else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
- if (memcmp(opt->data, &iface->dhcpv4_local, 4))
- return;
- } else if (iface->filter_class && opt->type == DHCPV4_OPT_USER_CLASS) {
- uint8_t *c = opt->data, *cend = &opt->data[opt->len];
- for (; c < cend && &c[*c] < cend; c = &c[1 + *c]) {
- size_t elen = strlen(iface->filter_class);
- if (*c == elen && !memcmp(&c[1], iface->filter_class, elen))
- return; // Ignore from homenet
- }
- } else if (opt->type == DHCPV4_OPT_LEASETIME && opt->len == 4)
- memcpy(&leasetime, opt->data, 4);
- else if (opt->type == DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE && opt->len > 0) {
- for (uint8_t i = 0; i < opt->len; i++) {
- if (opt->data[i] == 1) {
- accept_fr_nonce = true;
- break;
- }
- }
- }
- }
- if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
- reqmsg != DHCPV4_MSG_INFORM && reqmsg != DHCPV4_MSG_DECLINE &&
- reqmsg != DHCPV4_MSG_RELEASE)
- return;
- struct dhcpv4_assignment *lease = NULL;
- uint32_t serverid = iface->dhcpv4_local.s_addr;
- uint32_t fr_serverid = INADDR_ANY;
- if (reqmsg != DHCPV4_MSG_INFORM)
- lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
- &leasetime, hostname, hostname_len,
- accept_fr_nonce, &incl_fr_opt, &fr_serverid);
- if (!lease) {
- if (reqmsg == DHCPV4_MSG_REQUEST)
- msg = DHCPV4_MSG_NAK;
- else if (reqmsg == DHCPV4_MSG_DISCOVER)
- return;
- } else if (reqmsg == DHCPV4_MSG_DISCOVER)
- msg = DHCPV4_MSG_OFFER;
- else if (reqmsg == DHCPV4_MSG_REQUEST &&
- ((reqaddr && reqaddr != lease->addr) ||
- (req->ciaddr.s_addr && req->ciaddr.s_addr != lease->addr))) {
- msg = DHCPV4_MSG_NAK;
- /*
- * DHCP client requested an IP which we can't offer to him. Probably the
- * client changed the network or the network has been changed. The reply
- * type is set to DHCPV4_MSG_NAK, because the client should not use that IP.
- *
- * For modern devices we build an answer that includes a valid IP, like
- * a DHCPV4_MSG_ACK. The client will use that IP and doesn't need to
- * perform additional DHCP round trips.
- *
- */
- /*
- *
- * Buggy clients do serverid checking in nack messages; therefore set the
- * serverid in nack messages triggered by a previous force renew equal to
- * the server id in use at that time by the server
- *
- */
- if (fr_serverid)
- serverid = fr_serverid;
- if (req->ciaddr.s_addr &&
- ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
- (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
- req->ciaddr.s_addr = INADDR_ANY;
- }
- syslog(LOG_WARNING, "Received %s from %s on %s", dhcpv4_msg_to_string(reqmsg),
- odhcpd_print_mac(req->chaddr, req->hlen), iface->name);
- #ifdef WITH_UBUS
- if (reqmsg == DHCPV4_MSG_RELEASE)
- ubus_bcast_dhcp_event("dhcp.release", req->chaddr, req->hlen,
- &req->ciaddr, hostname, iface->ifname);
- #endif
- if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
- return;
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MESSAGE, 1, &msg);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &serverid);
- if (lease) {
- uint32_t val;
- reply.yiaddr.s_addr = lease->addr;
- val = htonl(leasetime);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
- if (leasetime != UINT32_MAX) {
- val = htonl(500 * leasetime / 1000);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
- val = htonl(875 * leasetime / 1000);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
- }
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4,
- &iface->dhcpv4_mask.s_addr);
- if (lease->hostname)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
- strlen(lease->hostname), lease->hostname);
- if (iface->dhcpv4_bcast.s_addr != INADDR_ANY)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_BROADCAST, 4, &iface->dhcpv4_bcast);
- if (incl_fr_opt) {
- if (reqmsg == DHCPV4_MSG_REQUEST) {
- struct dhcpv4_auth_forcerenew auth = {
- .protocol = 3,
- .algorithm = 1,
- .rdm = 0,
- .replay = {htonl(time(NULL)), htonl(++serial)},
- .type = 1,
- .key = {0},
- };
- memcpy(auth.key, lease->key, sizeof(auth.key));
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_AUTHENTICATION, sizeof(auth), &auth);
- } else {
- uint8_t one = 1;
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE,
- sizeof(one), &one);
- }
- }
- }
- struct ifreq ifr;
- memset(&ifr, 0, sizeof(ifr));
- strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
- if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
- uint16_t mtu = htons(ifr.ifr_mtu);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
- }
- if (iface->search && iface->search_len <= 255)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
- iface->search_len, iface->search);
- else if (!res_init() && _res.dnsrch[0] && _res.dnsrch[0][0]) {
- uint8_t search_buf[256];
- int len = dn_comp(_res.dnsrch[0], search_buf,
- sizeof(search_buf), NULL, NULL);
- if (len > 0)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SEARCH_DOMAIN,
- len, search_buf);
- }
- if (iface->dhcpv4_router_cnt == 0)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &iface->dhcpv4_local);
- else
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
- 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
- if (iface->dhcpv4_dns_cnt == 0)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER, 4, &iface->dhcpv4_local);
- else
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DNSSERVER,
- 4 * iface->dhcpv4_dns_cnt, iface->dhcpv4_dns);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_END, 0, NULL);
- struct sockaddr_in dest = *((struct sockaddr_in*)addr);
- if (req->giaddr.s_addr) {
- /*
- * relay agent is configured, send reply to the agent
- */
- dest.sin_addr = req->giaddr;
- dest.sin_port = htons(DHCPV4_SERVER_PORT);
- } else if (req->ciaddr.s_addr && req->ciaddr.s_addr != dest.sin_addr.s_addr) {
- /*
- * client has existing configuration (ciaddr is set) AND this address is
- * not the address it used for the dhcp message
- */
- dest.sin_addr = req->ciaddr;
- dest.sin_port = htons(DHCPV4_CLIENT_PORT);
- } else if ((ntohs(req->flags) & DHCPV4_FLAG_BROADCAST) ||
- req->hlen != reply.hlen || !reply.yiaddr.s_addr) {
- /*
- * client requests a broadcast reply OR we can't offer an IP
- */
- dest.sin_addr.s_addr = INADDR_BROADCAST;
- dest.sin_port = htons(DHCPV4_CLIENT_PORT);
- } else if (!req->ciaddr.s_addr && msg == DHCPV4_MSG_NAK) {
- /*
- * client has no previous configuration -> no IP, so we need to reply
- * with a broadcast packet
- */
- dest.sin_addr.s_addr = INADDR_BROADCAST;
- dest.sin_port = htons(DHCPV4_CLIENT_PORT);
- } else {
- struct arpreq arp = {.arp_flags = ATF_COM};
- /*
- * send reply to the newly (in this proccess) allocated IP
- */
- dest.sin_addr = reply.yiaddr;
- dest.sin_port = htons(DHCPV4_CLIENT_PORT);
- memcpy(arp.arp_ha.sa_data, req->chaddr, 6);
- memcpy(&arp.arp_pa, &dest, sizeof(arp.arp_pa));
- memcpy(arp.arp_dev, iface->ifname, sizeof(arp.arp_dev));
- if (ioctl(sock, SIOCSARP, &arp) < 0)
- syslog(LOG_ERR, "ioctl(SIOCSARP): %m");
- }
- if (sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
- (struct sockaddr*)&dest, sizeof(dest)) < 0)
- syslog(LOG_ERR, "Failed to send %s to %s - %s: %m",
- dhcpv4_msg_to_string(msg),
- dest.sin_addr.s_addr == INADDR_BROADCAST ?
- "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
- inet_ntoa(dest.sin_addr));
- else
- syslog(LOG_ERR, "Sent %s to %s - %s",
- dhcpv4_msg_to_string(msg),
- dest.sin_addr.s_addr == INADDR_BROADCAST ?
- "ff:ff:ff:ff:ff:ff": odhcpd_print_mac(req->chaddr, req->hlen),
- inet_ntoa(dest.sin_addr));
- #ifdef WITH_UBUS
- if (msg == DHCPV4_MSG_ACK)
- ubus_bcast_dhcp_event("dhcp.ack", req->chaddr, req->hlen, &reply.yiaddr,
- hostname, iface->ifname);
- #endif
- }
- static bool dhcpv4_assign(struct interface *iface,
- struct dhcpv4_assignment *assign, uint32_t raddr)
- {
- uint32_t start = ntohl(iface->dhcpv4_start_ip.s_addr);
- uint32_t end = ntohl(iface->dhcpv4_end_ip.s_addr);
- uint32_t count = end - start + 1;
- /* try to assign the IP the client asked for */
- if (start <= ntohl(raddr) && ntohl(raddr) <= end &&
- !find_assignment_by_addr(iface, raddr)) {
- assign->addr = raddr;
- syslog(LOG_INFO, "Assigning the IP the client asked for: %u.%u.%u.%u",
- ((uint8_t *)&assign->addr)[0],
- ((uint8_t *)&assign->addr)[1],
- ((uint8_t *)&assign->addr)[2],
- ((uint8_t *)&assign->addr)[3]);
- return true;
- }
- /* Seed RNG with checksum of hwaddress */
- uint32_t seed = 0;
- for (size_t i = 0; i < sizeof(assign->hwaddr); ++i) {
- /* Knuth's multiplicative method */
- uint8_t o = assign->hwaddr[i];
- seed += (o*2654435761) % UINT32_MAX;
- }
- srand(seed);
- uint32_t try = (((uint32_t)rand()) % count) + start;
- if (list_empty(&iface->dhcpv4_assignments)) {
- assign->addr = htonl(try);
- syslog(LOG_INFO, "Assigning mapped IP (empty list): %u.%u.%u.%u",
- ((uint8_t *)&assign->addr)[0],
- ((uint8_t *)&assign->addr)[1],
- ((uint8_t *)&assign->addr)[2],
- ((uint8_t *)&assign->addr)[3]);
- return true;
- }
- for (uint32_t i = 0; i < count; ++i) {
- if (!find_assignment_by_addr(iface, htonl(try))) {
- /* test was successful: IP address is not assigned, assign it */
- assign->addr = htonl(try);
- syslog(LOG_DEBUG, "Assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
- ((uint8_t *)&assign->addr)[0],
- ((uint8_t *)&assign->addr)[1],
- ((uint8_t *)&assign->addr)[2],
- ((uint8_t *)&assign->addr)[3],
- i, count);
- return true;
- }
- try = (((try - start) + 1) % count) + start;
- }
- syslog(LOG_WARNING, "Can't assign any IP address -> address space is full");
- return false;
- }
- static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
- enum dhcpv4_msg msg, const uint8_t *mac, const uint32_t reqaddr,
- uint32_t *leasetime, const char *hostname, const size_t hostname_len,
- const bool accept_fr_nonce, bool *incl_fr_opt, uint32_t *fr_serverid)
- {
- struct dhcpv4_assignment *a = find_assignment_by_hwaddr(iface, mac);
- struct dhcpv4_assignment *lease = NULL;
- time_t now = odhcpd_time();
- if (a && (a->flags & OAF_BOUND) && a->fr_ip) {
- *fr_serverid = a->fr_ip->addr.addr.in.s_addr;
- dhcpv4_fr_stop(a);
- }
- if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
- bool assigned = !!a;
- if (!a) {
- if (!iface->no_dynamic_dhcp) {
- /* Create new binding */
- a = calloc(1, sizeof(*a));
- if (!a) {
- syslog(LOG_ERR, "Failed to calloc binding on interface %s",
- iface->ifname);
- return NULL;
- }
- memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
- /* Don't consider new assignment as infinite */
- a->valid_until = now;
- assigned = dhcpv4_assign(iface, a, reqaddr);
- if (assigned) {
- a->iface = iface;
- list_add(&a->head, &iface->dhcpv4_assignments);
- }
- }
- } else if ((a->addr & iface->dhcpv4_mask.s_addr) !=
- (iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr)) {
- list_del(&a->head);
- assigned = dhcpv4_assign(iface, a, reqaddr);
- if (assigned)
- list_add(&a->head, &iface->dhcpv4_assignments);
- }
- if (assigned) {
- uint32_t my_leasetime;
- if (a->leasetime)
- my_leasetime = a->leasetime;
- else
- my_leasetime = iface->dhcpv4_leasetime;
- if ((*leasetime == 0) || (my_leasetime < *leasetime))
- *leasetime = my_leasetime;
- if (msg == DHCPV4_MSG_DISCOVER) {
- a->flags &= ~OAF_BOUND;
- *incl_fr_opt = accept_fr_nonce;
- if (!(a->flags & OAF_STATIC))
- a->valid_until = now;
- } else {
- if (hostname_len > 0) {
- a->hostname = realloc(a->hostname, hostname_len + 1);
- if (a->hostname) {
- memcpy(a->hostname, hostname, hostname_len);
- a->hostname[hostname_len] = 0;
- if (odhcpd_valid_hostname(a->hostname))
- a->flags &= ~OAF_BROKEN_HOSTNAME;
- else
- a->flags |= OAF_BROKEN_HOSTNAME;
- }
- }
- if (!(a->flags & OAF_BOUND)) {
- a->accept_fr_nonce = accept_fr_nonce;
- *incl_fr_opt = accept_fr_nonce;
- odhcpd_urandom(a->key, sizeof(a->key));
- a->flags |= OAF_BOUND;
- } else
- *incl_fr_opt = false;
- if (!(a->flags & OAF_STATIC))
- a->valid_until = ((*leasetime == UINT32_MAX) ? 0 : (time_t)(now + *leasetime));
- }
- } else if (!assigned && a) {
- /* Cleanup failed assignment */
- free_dhcpv4_assignment(a);
- a = NULL;
- }
- if (assigned && a)
- lease = a;
- } else if (msg == DHCPV4_MSG_RELEASE && a) {
- a->flags &= ~OAF_BOUND;
- if (!(a->flags & OAF_STATIC))
- a->valid_until = now - 1;
- } else if (msg == DHCPV4_MSG_DECLINE && a) {
- a->flags &= ~OAF_BOUND;
- if (!(a->flags & OAF_STATIC)) {
- memset(a->hwaddr, 0, sizeof(a->hwaddr));
- a->valid_until = now + 3600; /* Block address for 1h */
- }
- }
- dhcpv6_write_statefile();
- return lease;
- }
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