Merge pull request #22 from mehlis/log-dhcp4-events

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

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 9746aa2..9b9b528 100644 (file)
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -45,6 +45,29 @@ 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)
 {
@@ -334,9 +357,23 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
        } else if (reqmsg == DHCPV4_MSG_REQUEST && reqaddr.s_addr &&
                        reqaddr.s_addr != htonl(lease->addr)) {
                msg = DHCPV4_MSG_NAK;
-               lease = NULL;
+               /*
+                * 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;
 
@@ -384,8 +421,11 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                                        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)
@@ -419,6 +459,11 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                ioctl(sock, SIOCSARP, &arp);
        }
 
+       syslog(LOG_WARNING, "sending %s to %x:%x:%x:%x:%x:%x",
+                       dhcpv4_msg_to_string(msg),
+                       req->chaddr[0],req->chaddr[1],req->chaddr[2],
+                       req->chaddr[3],req->chaddr[4],req->chaddr[5]);
+
        sendto(sock, &reply, sizeof(reply), MSG_DONTWAIT,
                        (struct sockaddr*)&dest, sizeof(dest));
 }
@@ -491,7 +536,6 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
                }
        }
 
-       bool update_state = false;
        if (msg == DHCPV4_MSG_DISCOVER || msg == DHCPV4_MSG_REQUEST) {
                bool assigned = !!a;
                size_t hostlen = strlen(hostname) + 1;
@@ -530,24 +574,18 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
                        a = NULL;
                }
 
-               if (a)
-                       update_state = true;
-
                if (assigned && a)
                        lease = a;
        } else if (msg == DHCPV4_MSG_RELEASE) {
                if (a) {
                        a->valid_until = 0;
-                       update_state = true;
                }
        } else if (msg == DHCPV4_MSG_DECLINE) {
                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;
 }