iface->ifname);
return -1;
}
+ if (lease->dhcpv4_leasetime >= 60)
+ a->leasetime = lease->dhcpv4_leasetime;
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;
+ /* Infinite valid */
+ a->valid_until = 0;
// Assign to all interfaces
struct dhcpv4_assignment *c;
struct dhcpv4_assignment *a = list_first_entry(&iface->dhcpv4_assignments,
struct dhcpv4_assignment, head);
list_del(&a->head);
- free(a->hostname);
free(a);
}
*cookie = c + len;
}
-
-// Simple DHCPv6-server for information requests
+// Handler for DHCPv4 messages
static void handle_dhcpv4(void *addr, void *data, size_t len,
struct interface *iface, _unused void *dest_addr)
{
if (lease) {
reply.yiaddr.s_addr = htonl(lease->addr);
- uint32_t val = htonl(iface->dhcpv4_leasetime);
+ uint32_t val;
+ uint32_t leasetime;
+
+ if (lease->leasetime >= 60) {
+ leasetime = lease->leasetime;
+ } else {
+ leasetime = iface->dhcpv4_leasetime;
+ }
+
+ val = htonl(leasetime);
dhcpv4_put(&reply, &cookie, DHCPV4_OPT_LEASETIME, 4, &val);
- val = htonl(500 * iface->dhcpv4_leasetime / 1000);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
+ if (leasetime != UINT32_MAX) {
+ val = htonl(500 * leasetime / 1000);
+ dhcpv4_put(&reply, &cookie, DHCPV4_OPT_RENEW, 4, &val);
- val = htonl(875 * iface->dhcpv4_leasetime / 1000);
- dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
+ val = htonl(875 * leasetime / 1000);
+ dhcpv4_put(&reply, &cookie, DHCPV4_OPT_REBIND, 4, &val);
+ }
dhcpv4_put(&reply, &cookie, DHCPV4_OPT_NETMASK, 4, &ifnetmask.sin_addr);
(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 = 100;
uint32_t start = ntohl(iface->dhcpv4_start.s_addr);
uint32_t end = ntohl(iface->dhcpv4_end.s_addr);
uint32_t count = end - start + 1;
+ // 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;
}
a = c;
if (c->addr == raddr)
break;
- } else if (c->valid_until < now) {
+ } else if (!INFINITE_VALID(c->valid_until) && c->valid_until < now) {
list_del(&c->head);
free(c);
}
}
memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
memcpy(a->hostname, hostname, hostlen);
+ // Don't consider new assignment as infinite
+ a->valid_until = now;
assigned = dhcpv4_assign(iface, a, raddr);
}
a->head.prev->next = &a->head;
}
- // Was only a solicitation: mark binding for removal
- if (assigned && a->valid_until < now) {
- a->valid_until = (msg == DHCPV4_MSG_DISCOVER) ? 0 :
- (now + iface->dhcpv4_leasetime);
+ uint32_t leasetime;
+ if (a->leasetime) {
+ leasetime = a->leasetime;
+ } else {
+ leasetime = iface->dhcpv4_leasetime;
+ }
+
+ if (assigned) {
+ if (!INFINITE_VALID(a->valid_until))
+ // Was only a discover; mark binding for removal
+ a->valid_until = ((msg == DHCPV4_MSG_DISCOVER) ? now : ((leasetime == UINT32_MAX) ?
+ 0 : (time_t)(now + leasetime)));
} else if (!assigned && a) { // Cleanup failed assignment
free(a);
a = NULL;
if (assigned && a)
lease = a;
} else if (msg == DHCPV4_MSG_RELEASE) {
- if (a && a->valid_until != LONG_MAX)
- a->valid_until = 0;
- } else if (msg == DHCPV4_MSG_DECLINE && a->valid_until != LONG_MAX) {
+ if (a && !INFINITE_VALID(a->valid_until))
+ a->valid_until = now - 1;
+ } else if (msg == DHCPV4_MSG_DECLINE && a && !INFINITE_VALID(a->valid_until)) {
memset(a->hwaddr, 0, sizeof(a->hwaddr));
a->valid_until = now + 3600; // Block address for 1h
}