/**
* 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
#include "dhcpv4.h"
#include "dhcpv6.h"
-
+static void free_dhcpv4_assignment(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, struct in_addr reqaddr,
- const char *hostname);
+ uint32_t *leasetime, const char *hostname, const size_t hostname_len);
-// Create socket and register events
+/* 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) {
return -1;
}
- // Basic IPv6 configuration
+ /* Basic IPv4 configuration */
int val = 1;
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
return -1;
}
- // Create a range if not specified
+ /* Create a range if not specified */
struct ifreq ifreq;
strncpy(ifreq.ifr_name, iface->ifname, sizeof(ifreq.ifr_name));
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) |
}
- // Parse static entries
+ /* Parse static entries */
struct lease *lease;
list_for_each_entry(lease, &leases, head) {
- // Construct entry
- size_t hostlen = strlen(lease->hostname) + 1;
- struct dhcpv4_assignment *a = calloc(1, sizeof(*a) + hostlen);
+ /* Construct entry */
+ struct dhcpv4_assignment *a = calloc(1, sizeof(*a));
if (!a) {
syslog(LOG_ERR, "Calloc failed for static lease on interface %s",
iface->ifname);
return -1;
}
+
+ 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;
+ /* Static assignment */
+ a->flags |= OAF_STATIC;
+ /* Infinite valid */
+ a->valid_until = 0;
- // Assign to all interfaces
+ /* 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
+ } else if (c->addr == a->addr)
+ /* Already an assignment with that number */
break;
- }
}
- if (&c->head == &iface->dhcpv4_assignments) {
+
+ if (&c->head == &iface->dhcpv4_assignments)
list_add(&a->head, &iface->dhcpv4_assignments);
- }
- if (!a->head.next)
- free(a);
+ if (a->head.next) {
+ if (lease->hostname[0]) {
+ free(a->hostname);
+ a->hostname = strdup(lease->hostname);
+ }
+ } else
+ free_dhcpv4_assignment(a);
}
// Clean invalid assignments
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) !=
- (iface->dhcpv4_start.s_addr & smask->sin_addr.s_addr)) {
- list_del(&a->head);
- free(a);
- }
+ (iface->dhcpv4_start.s_addr & smask->sin_addr.s_addr))
+ free_dhcpv4_assignment(a);
}
-
- if (iface->dhcpv4_leasetime < 60)
- iface->dhcpv4_leasetime = 43200;
-
iface->dhcpv4_event.uloop.fd = sock;
iface->dhcpv4_event.handle_dgram = handle_dhcpv4;
odhcpd_register(&iface->dhcpv4_event);
} else if (iface->dhcpv4_assignments.next) {
- while (!list_empty(&iface->dhcpv4_assignments)) {
- struct dhcpv4_assignment *a = list_first_entry(&iface->dhcpv4_assignments,
- struct dhcpv4_assignment, head);
- list_del(&a->head);
- free(a->hostname);
- free(a);
- }
-
+ while (!list_empty(&iface->dhcpv4_assignments))
+ free_dhcpv4_assignment(list_first_entry(&iface->dhcpv4_assignments,
+ struct dhcpv4_assignment, head));
}
return 0;
}
+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";
+ default:
+ return "UNKNOWN";
+ }
+}
+
+static void free_dhcpv4_assignment(struct dhcpv4_assignment *a)
+{
+ if (a->head.next)
+ list_del(&a->head);
+
+ 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)
*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)
{
uint8_t msg = DHCPV4_MSG_ACK;
struct in_addr reqaddr = {INADDR_ANY};
+ uint32_t leasetime = 0;
+ size_t hostname_len = 0;
char hostname[256];
- hostname[0] = 0;
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) {
+ if (opt->type == DHCPV4_OPT_MESSAGE && opt->len == 1)
reqmsg = opt->data[0];
- } else if (opt->type == DHCPV4_OPT_HOSTNAME && opt->len > 0) {
- memcpy(hostname, opt->data, opt->len);
- hostname[opt->len] = 0;
- } else if (opt->type == DHCPV4_OPT_IPADDRESS && opt->len == 4) {
+ 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) {
+ 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) {
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);
}
if (reqmsg != DHCPV4_MSG_DISCOVER && reqmsg != DHCPV4_MSG_REQUEST &&
struct dhcpv4_assignment *lease = NULL;
if (reqmsg != DHCPV4_MSG_INFORM)
- lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr, hostname);
+ lease = dhcpv4_lease(iface, reqmsg, req->chaddr, reqaddr,
+ &leasetime, hostname, hostname_len);
if (!lease) {
if (reqmsg == DHCPV4_MSG_REQUEST)
msg = DHCPV4_MSG_NAK;
else if (reqmsg == DHCPV4_MSG_DISCOVER)
return;
- } else if (reqmsg == DHCPV4_MSG_DISCOVER) {
+ } else if (reqmsg == DHCPV4_MSG_DISCOVER)
msg = DHCPV4_MSG_OFFER;
- } else if (reqmsg == DHCPV4_MSG_REQUEST && reqaddr.s_addr &&
+ else if (reqmsg == DHCPV4_MSG_REQUEST && reqaddr.s_addr &&
reqaddr.s_addr != htonl(lease->addr)) {
msg = DHCPV4_MSG_NAK;
/*
*/
}
- syslog(LOG_WARNING, "received %s from %x:%x:%x:%x:%x:%x",
+ syslog(LOG_WARNING, "received %s from %02x:%02x:%02x:%02x:%02x:%02x",
dhcpv4_msg_to_string(reqmsg),
req->chaddr[0],req->chaddr[1],req->chaddr[2],
req->chaddr[3],req->chaddr[4],req->chaddr[5]);
dhcpv4_put(&reply, &cookie, DHCPV4_OPT_SERVERID, 4, &ifaddr.sin_addr);
if (lease) {
+ uint32_t val;
+
reply.yiaddr.s_addr = htonl(lease->addr);
- uint32_t val = htonl(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);
- if (lease->hostname[0])
+ if (lease->hostname)
dhcpv4_put(&reply, &cookie, DHCPV4_OPT_HOSTNAME,
strlen(lease->hostname), lease->hostname);
dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
}
- if (iface->search && iface->search_len <= 255) {
+ 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]) {
+ 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);
ioctl(sock, SIOCSARP, &arp);
}
- if (dest.sin_addr.s_addr == INADDR_BROADCAST) {
- /*
- * reply goes to IP broadcast -> MAC broadcast
- */
+ 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 {
+ 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",
+ syslog(LOG_WARNING, "sending %s to %02x:%02x:%02x:%02x:%02x:%02x - %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_INFO, "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_INFO, "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_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, struct in_addr reqaddr,
- const char *hostname)
+ uint32_t *leasetime, const char *hostname, const size_t hostname_len)
{
struct dhcpv4_assignment *lease = NULL;
uint32_t raddr = ntohl(reqaddr.s_addr);
a = c;
if (c->addr == raddr)
break;
- } else if (c->valid_until < now) {
- list_del(&c->head);
- free(c);
- }
+ } else if (!INFINITE_VALID(c->valid_until) && c->valid_until < now)
+ free_dhcpv4_assignment(c);
}
if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
bool assigned = !!a;
- size_t hostlen = strlen(hostname) + 1;
+ uint32_t my_leasetime;
- if (!a && !iface->no_dynamic_dhcp) { // Create new binding
- a = calloc(1, sizeof(*a) + hostlen);
+ if (!a && !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));
- memcpy(a->hostname, hostname, hostlen);
+ /* Don't consider new assignment as infinite */
+ a->valid_until = now;
assigned = dhcpv4_assign(iface, a, raddr);
}
- 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);
+ if (a->leasetime)
+ my_leasetime = a->leasetime;
+ else
+ my_leasetime = iface->dhcpv4_leasetime;
+
+ if ((*leasetime == 0) || (my_leasetime < *leasetime))
+ *leasetime = my_leasetime;
+
+ if (assigned) {
+ if (msg == DHCPV4_MSG_DISCOVER) {
+ a->flags &= ~OAF_BOUND;
+
+ 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;
+ }
+ }
- // Fixup list
- a->head.next->prev = &a->head;
- a->head.prev->next = &a->head;
- }
+ a->flags |= OAF_BOUND;
- // 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);
- } else if (!assigned && a) { // Cleanup failed assignment
- free(a);
+ 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) {
- if (a) {
- a->valid_until = 0;
+ } 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 */
}
- } else if (msg == DHCPV4_MSG_DECLINE) {
- 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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