Merge pull request #30 from dedeckeh/bugfixes

[project/odhcpd.git] / src / dhcpv4.c

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 7a68f66..1807c68 100644 (file)
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -20,6 +20,7 @@
 #include <stddef.h>
 #include <stdlib.h>
 #include <resolv.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 <net/if.h>
 #include <net/if_arp.h>
 #include <netinet/ip.h>


@@ -33,22 +34,45 @@
 
 
 static void handle_dhcpv4(void *addr, void *data, size_t len,
 
 
 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);
 
 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;
 }
 
 // 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) {
 
 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;
        }
                close(iface->dhcpv4_event.uloop.fd);
                iface->dhcpv4_event.uloop.fd = -1;
        }


@@ -58,6 +82,11 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
                        INIT_LIST_HEAD(&iface->dhcpv4_assignments);
 
                int sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
                        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;
 
                // Basic IPv6 configuration
                int val = 1;


@@ -65,7 +94,7 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
                setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
                setsockopt(sock, IPPROTO_IP, IP_PKTINFO, &val, sizeof(val));
 
                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;
                setsockopt(sock, IPPROTO_IP, IP_TOS, &val, sizeof(val));
 
                val = IP_PMTUDISC_DONT;


@@ -108,22 +137,28 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
 
                        if (start && end && start < end &&
                                        start > ntohl(addr.s_addr & ~mask.s_addr) &&
 
                        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);
                                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(100);
                                        iface->dhcpv4_end.s_addr = end | htonl(250);
                                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(100);
                                        iface->dhcpv4_end.s_addr = end | htonl(250);

-                               } else {
+                               } else if (ntohl(mask.s_addr) <= 0xffffffc0) {
+                                       iface->dhcpv4_start.s_addr = start | htonl(10);
+                                       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_start.s_addr = start | htonl(10);

-                                       iface->dhcpv4_end.s_addr = end | htonl(59);
+                                       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);

                                }
                        }
 
                                }
                        }
 


@@ -136,21 +171,30 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
                        // Construct entry
                        size_t hostlen = strlen(lease->hostname) + 1;
                        struct dhcpv4_assignment *a = calloc(1, sizeof(*a) + hostlen);
                        // 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->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);
 
                        // 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;
                                }
                        }
                                } 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);
 
                        if (!a->head.next)
                                free(a);


@@ -160,7 +204,7 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
                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) !=
                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);
                        }
                                list_del(&a->head);
                                free(a);
                        }


@@ -204,7 +248,7 @@ static void dhcpv4_put(struct dhcpv4_message *msg, uint8_t **cookie,
 
 // Simple DHCPv6-server for information requests
 static void handle_dhcpv4(void *addr, void *data, size_t len,
 
 // 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;
 {
        if (!iface->dhcpv4)
                return;


@@ -284,6 +328,13 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                } else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
                        if (memcmp(opt->data, &ifaddr.sin_addr, 4))
                                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
+                       }

                }
        }
 
                }
        }
 


@@ -303,8 +354,26 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                        return;
        } else if (reqmsg == DHCPV4_MSG_DISCOVER) {
                msg = DHCPV4_MSG_OFFER;
                        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;
 
        if (reqmsg == DHCPV4_MSG_DECLINE || reqmsg == DHCPV4_MSG_RELEASE)
                return;
 


@@ -340,18 +409,23 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                dhcpv4_put(&reply, &cookie, DHCPV4_OPT_MTU, 2, &mtu);
        }
 
                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]) {
        } 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)
 
 
        if (iface->dhcpv4_dns_cnt == 0)


@@ -365,16 +439,36 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 
        struct sockaddr_in dest = *((struct sockaddr_in*)addr);
        if (req->giaddr.s_addr) {
 
        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) {
                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) ||
                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 {
                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);
 
                dest.sin_addr = reply.yiaddr;
                dest.sin_port = htons(DHCPV4_CLIENT_PORT);
 


@@ -385,6 +479,25 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                ioctl(sock, SIOCSARP, &arp);
        }
 
                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));
 }
        sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
                        (struct sockaddr*)&dest, sizeof(dest));
 }


@@ -393,12 +506,12 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 static bool dhcpv4_assign(struct interface *iface,
                struct dhcpv4_assignment *assign, uint32_t raddr)
 {
 static bool dhcpv4_assign(struct interface *iface,
                struct dhcpv4_assignment *assign, uint32_t raddr)
 {

-       const unsigned tries = 10;
+       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;
 
        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
+       // Seed RNG with checksum of hwaddress

        uint32_t seed = 0;
        for (size_t i = 0; i < sizeof(assign->hwaddr); ++i)
                seed += assign->hwaddr[i];
        uint32_t seed = 0;
        for (size_t i = 0; i < sizeof(assign->hwaddr); ++i)
                seed += assign->hwaddr[i];


@@ -447,22 +560,26 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 
        struct dhcpv4_assignment *c, *n, *a = NULL;
        list_for_each_entry_safe(c, n, &iface->dhcpv4_assignments, head) {
 
        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;
                        a = c;

-                       break;
+                       if (c->addr == raddr)
+                               break;

                } else if (c->valid_until < now) {
                        list_del(&c->head);
                        free(c);
                }
        }
 
                } 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 (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);
 
                        memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
                        memcpy(a->hostname, hostname, hostlen);
 


@@ -471,6 +588,10 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 
                if (assigned && !a->hostname[0] && hostname) {
                        a = realloc(a, sizeof(*a) + 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
                        memcpy(a->hostname, hostname, hostlen);
 
                        // Fixup list


@@ -490,18 +611,14 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
                if (assigned && a)
                        lease = a;
        } else if (msg == DHCPV4_MSG_RELEASE) {
                if (assigned && a)
                        lease = a;
        } else if (msg == DHCPV4_MSG_RELEASE) {

-               if (a) {
+               if (a && a->valid_until != LONG_MAX)

                        a->valid_until = 0;
                        a->valid_until = 0;

-                       update_state = true;
-               }
-       } else if (msg == DHCPV4_MSG_DECLINE) {
+       } else if (msg == DHCPV4_MSG_DECLINE && a->valid_until != LONG_MAX) {

                memset(a->hwaddr, 0, sizeof(a->hwaddr));
                a->valid_until = now + 3600; // Block address for 1h
                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;
 }
 
        return lease;
 }