Hide details of the listen mode implementation in packet.c.

ndhc/arp.c

@@ -186,7 +186,7 @@ static void arp_failed(struct client_state_t *cs)
     cs->requestedIP = 0;
     cs->timeout = 0;
     cs->packetNum = 0;
-    change_listen_mode(cs, LM_RAW);
+    set_listen_raw(cs);
 }
 
 void arp_gw_failed(struct client_state_t *cs)
@@ -200,7 +200,7 @@ void arp_gw_failed(struct client_state_t *cs)
     cs->timeout = 0;
     cs->requestedIP = 0;
     cs->packetNum = 0;
-    change_listen_mode(cs, LM_RAW);
+    set_listen_raw(cs);
 }
 
 void arp_success(struct client_state_t *cs)
@@ -218,7 +218,7 @@ void arp_success(struct client_state_t *cs)
              ((cs->arpPrevState == DS_RENEWING ||
                cs->arpPrevState == DS_REBINDING)
               ? IFCHANGE_RENEW : IFCHANGE_BOUND));
-    change_listen_mode(cs, LM_NONE);
+    set_listen_none(cs);
     write_leasefile(temp_addr);
     if (client_config.quit_after_lease)
         exit(EXIT_SUCCESS);

ndhc/config.h

@@ -23,12 +23,6 @@
 
 #include <stdint.h>
 
-enum {
-    LM_NONE = 0,
-    LM_KERNEL,
-    LM_RAW
-};
-
 enum {
     IFS_NONE = 0,
     IFS_UP,

ndhc/ndhc.c

@@ -63,7 +63,7 @@ struct client_state_t cs = {
     .dhcpState = DS_SELECTING,
     .arpPrevState = DS_SELECTING,
     .ifsPrevState = IFS_NONE,
-    .listenMode = LM_NONE,
+    .listenMode = 0,
     .packetNum = 0,
     .xid = 0,
     .timeout = 0,
@@ -161,7 +161,7 @@ static void do_work(void)
         suicide("epoll_create1 failed");
     setup_signals(&cs);
     epoll_add(&cs, cs.nlFd);
-    change_listen_mode(&cs, LM_RAW);
+    set_listen_raw(&cs);
     timeout_action(&cs);
 
     for (;;) {

ndhc/netlink.c

@@ -117,7 +117,7 @@ static void takedown_if(struct client_state_t *cs)
     cs->timeout = 0;
     cs->requestedIP = 0;
     cs->packetNum = 0;
-    change_listen_mode(cs, LM_RAW);
+    set_listen_raw(cs);
 }
 
 // Decode netlink messages and process them

ndhc/packet.c

@@ -49,6 +49,12 @@
 #include "strl.h"
 #include "random.h"
 
+typedef enum {
+    LM_NONE = 0,
+    LM_COOKED,
+    LM_RAW
+} listen_mode_t;
+
 // Returns fd of new udp socket bound on success, or -1 on failure.
 static int create_udp_socket(uint32_t ip, uint16_t port, char *iface)
 {
@@ -433,7 +439,7 @@ static int send_dhcp_raw(struct dhcpmsg *payload)
 }
 
 // Switch listen socket between raw (if-bound), kernel (ip-bound), and none
-void change_listen_mode(struct client_state_t *cs, int new_mode)
+static void change_listen_mode(struct client_state_t *cs, int new_mode)
 {
     cs->listenMode = new_mode;
     if (cs->listenFd >= 0) {
@@ -441,7 +447,7 @@ void change_listen_mode(struct client_state_t *cs, int new_mode)
         close(cs->listenFd);
         cs->listenFd = -1;
     }
-    if (new_mode != (LM_RAW || LM_KERNEL)) {
+    if (new_mode != (LM_RAW || LM_COOKED)) {
         log_line("Stopped listening for DHCP packets.");
         return;
     }
@@ -457,6 +463,21 @@ void change_listen_mode(struct client_state_t *cs, int new_mode)
              new_mode == LM_RAW ? "raw" : "cooked");
 }
 
+void set_listen_raw(struct client_state_t *cs)
+{
+    change_listen_mode(cs, LM_RAW);
+}
+
+void set_listen_cooked(struct client_state_t *cs)
+{
+    change_listen_mode(cs, LM_COOKED);
+}
+
+void set_listen_none(struct client_state_t *cs)
+{
+    change_listen_mode(cs, LM_NONE);
+}
+
 void handle_packet(struct client_state_t *cs)
 {
     uint8_t *message = NULL;
@@ -464,7 +485,7 @@ void handle_packet(struct client_state_t *cs)
     struct dhcpmsg packet;
     ssize_t optlen;
 
-    if (cs->listenMode == LM_KERNEL)
+    if (cs->listenMode == LM_COOKED)
         len = get_cooked_packet(&packet, cs->listenFd);
     else if (cs->listenMode == LM_RAW)
         len = get_raw_packet(&packet, cs->listenFd);

ndhc/packet.h

@@ -75,7 +75,9 @@ struct udp_dhcp_packet {
     struct dhcpmsg data;
 };
 
-void change_listen_mode(struct client_state_t *cs, int new_mode);
+void set_listen_raw(struct client_state_t *cs);
+void set_listen_cooked(struct client_state_t *cs);
+void set_listen_none(struct client_state_t *cs);
 void handle_packet(struct client_state_t *cs);
 int send_discover(uint32_t xid, uint32_t requested);
 int send_selecting(uint32_t xid, uint32_t server, uint32_t requested);

ndhc/state.c

@@ -70,7 +70,7 @@ static void requesting_timeout(struct client_state_t *cs)
         cs->dhcpState = DS_SELECTING;
         cs->timeout = 0;
         cs->packetNum = 0;
-        change_listen_mode(cs, LM_RAW);
+        set_listen_raw(cs);
     }
 }
 
@@ -79,7 +79,7 @@ static void requesting_timeout(struct client_state_t *cs)
 static void bound_timeout(struct client_state_t *cs)
 {
     cs->dhcpState = DS_RENEWING;
-    change_listen_mode(cs, LM_KERNEL);
+    set_listen_cooked(cs);
     log_line("Entering renew state.");
     renewing_timeout(cs);
 }
@@ -91,7 +91,7 @@ static void lease_timedout(struct client_state_t *cs)
     ifchange(NULL, IFCHANGE_DECONFIG);
     cs->timeout = 0;
     cs->packetNum = 0;
-    change_listen_mode(cs, LM_RAW);
+    set_listen_raw(cs);
 }
 
 // Triggered when a DHCP renew request has been sent and no reply has been
@@ -178,7 +178,7 @@ static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
             cs->timeout = 30000;
             cs->requestedIP = 0;
             cs->packetNum = 0;
-            change_listen_mode(cs, LM_RAW);
+            set_listen_raw(cs);
         }
 
     } else if (*message == DHCPNAK) {
@@ -190,7 +190,7 @@ static void an_packet(struct client_state_t *cs, struct dhcpmsg *packet,
         cs->timeout = 3000;
         cs->requestedIP = 0;
         cs->packetNum = 0;
-        change_listen_mode(cs, LM_RAW);
+        set_listen_raw(cs);
     }
 }
 
@@ -255,7 +255,7 @@ static void nfrelease(struct client_state_t *cs)
 static void frelease(struct client_state_t *cs)
 {
     log_line("Entering released state.");
-    change_listen_mode(cs, LM_NONE);
+    set_listen_none(cs);
     cs->dhcpState = DS_RELEASED;
     cs->timeout = -1;
 }
@@ -269,7 +269,7 @@ static void frenew(struct client_state_t *cs)
         case DS_BOUND_GW_CHECK:
             arp_close_fd(cs);
             cs->dhcpState = DS_RENEWING;
-            change_listen_mode(cs, LM_KERNEL);
+            set_listen_cooked(cs);
             send_renew(cs->xid, cs->serverAddr, cs->requestedIP);
             break;
         case DS_ARP_CHECK:
@@ -278,7 +278,7 @@ static void frenew(struct client_state_t *cs)
                 cs->dhcpState = cs->arpPrevState;
             goto retry;
         case DS_RELEASED:
-            change_listen_mode(cs, LM_RAW);
+            set_listen_raw(cs);
             cs->dhcpState = DS_SELECTING;
             break;
         case DS_RENEWING: