dhcpv4_assign: try 100 times to find a IP

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

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 9b9b528..1807c68 100644 (file)
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -137,8 +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) |
@@ -439,16 +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);
 
@@ -459,10 +479,24 @@ 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]);
+       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));
@@ -472,12 +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)
 {
-       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;
 
-       // 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];
@@ -577,10 +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
        }