#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>
static void handle_dhcpv4(void *addr, void *data, size_t len,
- struct interface *iface);
+ struct interface *iface, void *dest_addr);
static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
enum dhcpv4_msg msg, const uint8_t *mac, struct in_addr reqaddr,
const char *hostname);
-
// Create socket and register events
int init_dhcpv4(void)
{
return 0;
}
+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";
+ default:
+ return "UNKNOWN";
+ }
+}
int setup_dhcpv4_interface(struct interface *iface, bool enable)
{
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;
}
INIT_LIST_HEAD(&iface->dhcpv4_assignments);
int sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
+ if (sock < 0) {
+ syslog(LOG_ERR, "Failed to create DHCPv4 server socket: %s",
+ strerror(errno));
+ return -1;
+ }
// Basic IPv6 configuration
int val = 1;
setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
setsockopt(sock, IPPROTO_IP, IP_PKTINFO, &val, sizeof(val));
- val = IPTOS_CLASS_CS6;
+ val = IPTOS_PREC_INTERNETCONTROL;
setsockopt(sock, IPPROTO_IP, IP_TOS, &val, sizeof(val));
val = IP_PMTUDISC_DONT;
if (start && end && start < end &&
start > ntohl(addr.s_addr & ~mask.s_addr) &&
- (start & ntohl(mask.s_addr)) == start &&
- (end & ntohl(mask.s_addr)) == end) {
+ (start & ntohl(~mask.s_addr)) == start &&
+ (end & ntohl(~mask.s_addr)) == end) {
iface->dhcpv4_start.s_addr = htonl(start) |
(addr.s_addr & mask.s_addr);
iface->dhcpv4_end.s_addr = htonl(end) |
(addr.s_addr & mask.s_addr);
- } else if (ntohl(mask.s_addr) <= 0xffffffc0) {
+ } else if (ntohl(mask.s_addr) <= 0xfffffff0) {
start = addr.s_addr & mask.s_addr;
end = addr.s_addr & mask.s_addr;
if (ntohl(mask.s_addr) <= 0xffffff00) {
- iface->dhcpv4_start.s_addr = start | htonl(20);
- iface->dhcpv4_end.s_addr = end | htonl(199);
- } else {
+ iface->dhcpv4_start.s_addr = start | htonl(100);
+ iface->dhcpv4_end.s_addr = end | htonl(250);
+ } else if (ntohl(mask.s_addr) <= 0xffffffc0) {
iface->dhcpv4_start.s_addr = start | htonl(10);
- iface->dhcpv4_end.s_addr = end | htonl(59);
+ iface->dhcpv4_end.s_addr = end | htonl(60);
+ } else if (ntohl(mask.s_addr) <= 0xffffffe0) {
+ iface->dhcpv4_start.s_addr = start | htonl(10);
+ iface->dhcpv4_end.s_addr = end | htonl(30);
+ } else {
+ iface->dhcpv4_start.s_addr = start | htonl(3);
+ iface->dhcpv4_end.s_addr = end | htonl(12);
}
}
// Construct entry
size_t hostlen = strlen(lease->hostname) + 1;
struct dhcpv4_assignment *a = calloc(1, sizeof(*a) + hostlen);
-
+ if (!a) {
+ syslog(LOG_ERR, "Calloc failed for static lease on interface %s",
+ iface->ifname);
+ return -1;
+ }
a->addr = ntohl(lease->ipaddr.s_addr);
memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
memcpy(a->hostname, lease->hostname, hostlen);
+ a->valid_until = LONG_MAX;
// Assign to all interfaces
struct dhcpv4_assignment *c;
list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
if (c->addr > a->addr) {
list_add_tail(&a->head, &c->head);
+ break;
} else if (c->addr == a->addr) {
// Already an assignment with that number
break;
}
}
+ if (&c->head == &iface->dhcpv4_assignments) {
+ list_add(&a->head, &iface->dhcpv4_assignments);
+ }
if (!a->head.next)
free(a);
struct dhcpv4_assignment *a, *n;
list_for_each_entry_safe(a, n, &iface->dhcpv4_assignments, head) {
if ((htonl(a->addr) & smask->sin_addr.s_addr) !=
- (saddr->sin_addr.s_addr & smask->sin_addr.s_addr)) {
+ (iface->dhcpv4_start.s_addr & smask->sin_addr.s_addr)) {
list_del(&a->head);
free(a);
}
if (iface->dhcpv4_leasetime < 60)
- iface->dhcpv4_leasetime = 1800;
+ iface->dhcpv4_leasetime = 43200;
iface->dhcpv4_event.uloop.fd = sock;
iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
struct dhcpv4_assignment *a = list_first_entry(&iface->dhcpv4_assignments,
struct dhcpv4_assignment, head);
list_del(&a->head);
- free(a->hostname);
free(a);
}
// Simple DHCPv6-server for information requests
static void handle_dhcpv4(void *addr, void *data, size_t len,
- struct interface *iface)
+ struct interface *iface, _unused void *dest_addr)
{
if (!iface->dhcpv4)
return;
} else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
if (memcmp(opt->data, &ifaddr.sin_addr, 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
+ }
}
}
return;
} else if (reqmsg == DHCPV4_MSG_DISCOVER) {
msg = DHCPV4_MSG_OFFER;
+ } else if (reqmsg == DHCPV4_MSG_REQUEST && reqaddr.s_addr &&
+ reqaddr.s_addr != htonl(lease->addr)) {
+ msg = DHCPV4_MSG_NAK;
+ /*
+ * DHCP client requested an IP which we can't offer to him. Probably the
+ * client changed the network. 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.
+ *
+ */
}
+ syslog(LOG_WARNING, "received %s from %x:%x:%x:%x:%x:%x",
+ dhcpv4_msg_to_string(reqmsg),
+ req->chaddr[0],req->chaddr[1],req->chaddr[2],
+ req->chaddr[3],req->chaddr[4],req->chaddr[5]);
+
if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
return;
dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
}
- if (iface->search) {
- char b[256];
- if (dn_expand(iface->search, iface->search + iface->search_len,
- iface->search, b, sizeof(b)) > 0)
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DOMAIN, strlen(b), b);
+ 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]) {
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_DOMAIN,
- strlen(_res.dnsrch[0]), _res.dnsrch[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);
}
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &ifaddr.sin_addr);
-
+ if (iface->dhcpv4_router_cnt == 0)
+ dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER, 4, &ifaddr.sin_addr);
+ else
+ dhcpv4_put(&reply, &cookie, DHCPV4_OPT_ROUTER,
+ 4 * iface->dhcpv4_router_cnt, iface->dhcpv4_router);
if (iface->dhcpv4_dns_cnt == 0)
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) {
+ 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 {
+ /*
+ * send reply to the newly (in this proccess) allocated IP
+ */
dest.sin_addr = reply.yiaddr;
dest.sin_port = htons(DHCPV4_CLIENT_PORT);
ioctl(sock, SIOCSARP, &arp);
}
+ if (dest.sin_addr.s_addr == INADDR_BROADCAST) {
+ /*
+ * reply goes to IP broadcast -> MAC broadcast
+ */
+ syslog(LOG_WARNING, "sending %s to ff:ff:ff:ff:ff:ff - %s",
+ dhcpv4_msg_to_string(msg),
+ inet_ntoa(dest.sin_addr));
+ } else {
+ /*
+ * reply is send directly to IP,
+ * MAC is assumed to be the same as the request
+ */
+ syslog(LOG_WARNING, "sending %s to %x:%x:%x:%x:%x:%x - %s",
+ dhcpv4_msg_to_string(msg),
+ req->chaddr[0],req->chaddr[1],req->chaddr[2],
+ req->chaddr[3],req->chaddr[4],req->chaddr[5],
+ inet_ntoa(dest.sin_addr));
+ }
+
sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
(struct sockaddr*)&dest, sizeof(dest));
}
+static bool dhcpv4_test(struct interface *iface, uint32_t try)
+{
+ struct dhcpv4_assignment *c;
+ list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
+ if (c->addr == try) {
+ return false;
+ }
+ }
+ return true;
+}
static bool dhcpv4_assign(struct interface *iface,
struct dhcpv4_assignment *assign, uint32_t raddr)
{
- const unsigned tries = 10;
uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
uint32_t count = end - start + 1;
- // Seed RNG with checksum of DUID
+ // try to assign the IP the client asked for
+ if (start <= raddr && raddr <= end && dhcpv4_test(iface, raddr)) {
+ assign->addr = raddr;
+ list_add(&assign->head, &iface->dhcpv4_assignments);
+ syslog(LOG_DEBUG, "assigning the IP the client asked for: %u.%u.%u.%u",
+ (assign->addr & 0xff000000) >> 24,
+ (assign->addr & 0x00ff0000) >> 16,
+ (assign->addr & 0x0000ff00) >> 8,
+ (assign->addr & 0x000000ff));
+ return true;
+ }
+
+ // Seed RNG with checksum of hwaddress
uint32_t seed = 0;
- for (size_t i = 0; i < sizeof(assign->hwaddr); ++i)
- seed += assign->hwaddr[i];
+ 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);
- // Try to assign up to 100x
- for (unsigned i = 0; i < tries; ++i) {
- uint32_t try = (((uint32_t)rand()) % count) + start;
- if (i == 0 && raddr >= start && raddr <= end)
- try = raddr;
- else if (i == tries - 1)
- try = start;
+ uint32_t try = (((uint32_t)rand()) % count) + start;
+
+ if (list_empty(&iface->dhcpv4_assignments)) {
+ assign->addr = try;
+ list_add(&assign->head, &iface->dhcpv4_assignments);
+ syslog(LOG_DEBUG, "assigning mapped IP (empty list): %u.%u.%u.%u",
+ (assign->addr & 0xff000000) >> 24,
+ (assign->addr & 0x00ff0000) >> 16,
+ (assign->addr & 0x0000ff00) >> 8,
+ (assign->addr & 0x000000ff));
+ return true;
+ }
- if (list_empty(&iface->dhcpv4_assignments)) {
+ for (uint32_t i = 0; i < count; ++i) {
+ if (dhcpv4_test(iface, try)) {
+ /* test was successful: IP address is not assigned, assign it */
assign->addr = try;
list_add(&assign->head, &iface->dhcpv4_assignments);
+ syslog(LOG_DEBUG, "assigning mapped IP: %u.%u.%u.%u (try %u of %u)",
+ (assign->addr & 0xff000000) >> 24,
+ (assign->addr & 0x00ff0000) >> 16,
+ (assign->addr & 0x0000ff00) >> 8,
+ (assign->addr & 0x000000ff), i, count);
return true;
}
-
- struct dhcpv4_assignment *c;
- list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
- if (c->addr > try) {
- assign->addr = try;
- list_add_tail(&assign->head, &c->head);
- return true;
- } else if (c->addr == try) {
- if (i < tries - 1)
- break;
- else
- ++try;
- }
- }
+ try = (((try - start) + 1) % count) + start;
}
+ syslog(LOG_DEBUG, "can't assign any IP address -> address space is full");
return false;
}
struct dhcpv4_assignment *c, *n, *a = NULL;
list_for_each_entry_safe(c, n, &iface->dhcpv4_assignments, head) {
- if (c->addr == raddr && !memcmp(c->hwaddr, mac, 6)) {
+ if (!memcmp(c->hwaddr, mac, 6)) {
a = c;
- break;
+ if (c->addr == raddr)
+ break;
} else if (c->valid_until < now) {
list_del(&c->head);
free(c);
}
}
- bool update_state = false;
if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
bool assigned = !!a;
size_t hostlen = strlen(hostname) + 1;
if (!a && !iface->no_dynamic_dhcp) { // Create new binding
a = calloc(1, sizeof(*a) + hostlen);
+ if (!a) {
+ syslog(LOG_ERR, "Failed to calloc binding on interface %s", iface->ifname);
+ return NULL;
+ }
memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
memcpy(a->hostname, hostname, hostlen);
if (assigned && !a->hostname[0] && hostname) {
a = realloc(a, sizeof(*a) + hostlen);
+ if (!a) {
+ syslog(LOG_ERR, "Failed to realloc binding on interface %s", iface->ifname);
+ return NULL;
+ }
memcpy(a->hostname, hostname, hostlen);
// Fixup list
if (assigned && a)
lease = a;
} else if (msg == DHCPV4_MSG_RELEASE) {
- if (a) {
+ if (a && a->valid_until != LONG_MAX)
a->valid_until = 0;
- update_state = true;
- }
- } else if (msg == DHCPV4_MSG_DECLINE) {
+ } else if (msg == DHCPV4_MSG_DECLINE && a && a->valid_until != LONG_MAX) {
memset(a->hwaddr, 0, sizeof(a->hwaddr));
a->valid_until = now + 3600; // Block address for 1h
- update_state = true;
}
- if (update_state)
- dhcpv6_write_statefile();
+ dhcpv6_write_statefile();
return lease;
}
projects / project / odhcpd.git / blobdiff