X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fodhcpd.git;a=blobdiff_plain;f=src%2Fdhcpv4.c;h=fdf5f685189346fa99b703f7336a642a6fa29744;hp=7b200cded2b5e70725a8427c0c51b71abd98fa5a;hb=cf90f5ab2d5b4b6cece7d0096df12eb29e7d1568;hpb=de90ff1b27ef8e41c819d40d80f0fd6d8be86ded

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 7b200cd..fdf5f68 100644
--- 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)
 {
@@ -114,8 +137,8 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
 
 			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) |
@@ -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;
 
@@ -402,16 +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) {
+		/*
+		 * 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 || !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);
 
@@ -422,6 +479,25 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 		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));
 }
@@ -535,10 +611,9 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 		if (assigned && a)
 			lease = a;
 	} else if (msg == DHCPV4_MSG_RELEASE) {
-		if (a) {
+		if (a && a->valid_until != LONG_MAX)
 			a->valid_until = 0;
-		}
-	} 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
 	}