Move dhcp packet reply code to packet.c.

ndhc/config.h

@@ -1,6 +1,9 @@
 #ifndef DHCPC_H_
 #define DHCPC_H_
 
+#define NUMPACKETS 3 /* number of packets to send before delay */
+#define RETRY_DELAY 30 /* time in seconds to delay after sending NUMPACKETS */
+
 enum {
 	DS_NULL = 0,
 	DS_INIT_SELECTING,

ndhc/ndhc.c

@@ -59,8 +59,6 @@
 #include "io.h"
 
 #define VERSION "1.0"
-#define NUMPACKETS 3 /* number of packets to send before delay */
-#define RETRY_DELAY 30 /* time in seconds to delay after sending NUMPACKETS */
 
 struct client_state_t cs = {
     .dhcpState = DS_INIT_SELECTING,
@@ -150,7 +148,7 @@ static void show_usage(void)
 }
 
 /* Switch listen socket between raw (if-bound), kernel (ip-bound), and none */
-static void change_listen_mode(int new_mode)
+void change_listen_mode(int new_mode)
 {
     log_line("entering %s listen mode",
              new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
@@ -260,6 +258,19 @@ static struct arpMsg arpreply;
 static int arpreply_offset;
 static struct dhcpMessage arp_dhcp_packet;
 
+void arp_check(struct dhcpMessage *packet)
+{
+    cs.arpPrevState = cs.dhcpState;
+    cs.dhcpState = DS_ARP_CHECK;
+    memcpy(&arp_dhcp_packet, packet, sizeof (struct dhcpMessage));
+    cs.arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0,
+                        client_config.arp, client_config.interface);
+    epoll_add(cs.arpFd);
+    cs.timeout = 2000;
+    memset(&arpreply, 0, sizeof arpreply);
+    arpreply_offset = 0;
+}
+
 static void arp_failed(void)
 {
     log_line("Offered address is in use: declining.");
@@ -426,127 +437,6 @@ static void handle_timeout(void)
     }
 }
 
-static void init_selecting_packet(struct dhcpMessage *packet,
-                                  unsigned char *message)
-{
-    unsigned char *temp = NULL;
-    /* Must be a DHCPOFFER to one of our xid's */
-    if (*message == DHCPOFFER) {
-        if ((temp = get_option(packet, DHCP_SERVER_ID))) {
-            /* Memcpy to a temp buffer to force alignment */
-            memcpy(&cs.serverAddr, temp, 4);
-            cs.xid = packet->xid;
-            cs.requestedIP = packet->yiaddr;
-
-            /* enter requesting state */
-            cs.dhcpState = DS_REQUESTING;
-            cs.timeout = 0;
-            cs.packetNum = 0;
-        } else {
-            log_line("No server ID in message");
-        }
-    }
-}
-
-static void dhcp_ack_or_nak_packet(struct dhcpMessage *packet,
-                                   unsigned char *message)
-{
-    unsigned char *temp = NULL;
-    if (*message == DHCPACK) {
-        if (!(temp = get_option(packet, DHCP_LEASE_TIME))) {
-            log_line("No lease time received, assuming 1h.");
-            cs.lease = 60 * 60;
-        } else {
-            /* Memcpy to a temp buffer to force alignment */
-            memcpy(&cs.lease, temp, 4);
-            cs.lease = ntohl(cs.lease);
-            /* Enforce upper and lower bounds on lease. */
-            cs.lease &= 0x0fffffff;
-            if (cs.lease < RETRY_DELAY)
-                cs.lease = RETRY_DELAY;
-        }
-
-        cs.arpPrevState = cs.dhcpState;
-        cs.dhcpState = DS_ARP_CHECK;
-        memcpy(&arp_dhcp_packet, packet, sizeof (struct dhcpMessage));
-        cs.arpFd = arpping(arp_dhcp_packet.yiaddr, NULL, 0,
-                        client_config.arp, client_config.interface);
-        epoll_add(cs.arpFd);
-        cs.timeout = 2000;
-        memset(&arpreply, 0, sizeof arpreply);
-        arpreply_offset = 0;
-        // Can transition to DS_BOUND or DS_INIT_SELECTING.
-
-    } else if (*message == DHCPNAK) {
-        /* return to init state */
-        log_line("Received DHCP NAK.");
-        run_script(packet, SCRIPT_NAK);
-        if (cs.dhcpState != DS_REQUESTING)
-            run_script(NULL, SCRIPT_DECONFIG);
-        cs.dhcpState = DS_INIT_SELECTING;
-        cs.timeout = 0;
-        cs.requestedIP = 0;
-        cs.packetNum = 0;
-        change_listen_mode(LM_RAW);
-        // XXX: this isn't rfc compliant: should be exp backoff
-        sleep(3); /* avoid excessive network traffic */
-    }
-}
-
-static void handle_packet(void)
-{
-    unsigned char *message = NULL;
-    int len;
-    struct dhcpMessage packet;
-
-    if (cs.listenMode == LM_KERNEL)
-        len = get_packet(&packet, cs.listenFd);
-    else if (cs.listenMode == LM_RAW)
-        len = get_raw_packet(&packet, cs.listenFd);
-    else /* LM_NONE */
-        return;
-
-    if (len == -1 && errno != EINTR) {
-        log_error("reopening socket.");
-        change_listen_mode(cs.listenMode); /* just close and reopen */
-    }
-
-    if (len < 0)
-        return;
-
-    if (packet.xid != cs.xid) {
-        log_line("Ignoring XID %lx (our xid is %lx).",
-                 (uint32_t) packet.xid, cs.xid);
-        return;
-    }
-
-    if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
-        log_line("couldnt get option from packet -- ignoring");
-        return;
-    }
-
-    switch (cs.dhcpState) {
-        case DS_INIT_SELECTING:
-            init_selecting_packet(&packet, message);
-            break;
-        case DS_ARP_CHECK:
-            /* We ignore dhcp packets for now.  This state will
-             * be changed by the callback for arp ping.
-             */
-            break;
-        case DS_RENEW_REQUESTED:
-        case DS_REQUESTING:
-        case DS_RENEWING:
-        case DS_REBINDING:
-            dhcp_ack_or_nak_packet(&packet, message);
-            break;
-        case DS_BOUND:
-        case DS_RELEASED:
-        default:
-            break;
-    }
-}
-
 typedef uint32_t aliased_uint32_t __attribute__((__may_alias__));
 static void handle_arp_response(void)
 {
@@ -655,7 +545,7 @@ static void do_work(void)
             if (fd == cs.signalFd)
                 signal_dispatch();
             else if (fd == cs.listenFd)
-                handle_packet();
+                handle_packet(&cs);
             else if (fd == cs.arpFd)
                 handle_arp_response();
             else

ndhc/packet.c

@@ -10,6 +10,8 @@
 #include <errno.h>
 
 #include "packet.h"
+#include "clientpacket.h"
+#include "script.h"
 #include "log.h"
 #include "io.h"
 #include "dhcpd.h"
@@ -65,8 +67,8 @@ uint16_t checksum(void *addr, int count)
 /* Constuct a ip/udp header for a packet, and specify the source and dest
  * hardware address */
 int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
-	       int source_port, uint32_t dest_ip, int dest_port,
+               int source_port, uint32_t dest_ip, int dest_port,
-	       unsigned char *dest_arp, int ifindex)
+               unsigned char *dest_arp, int ifindex)
 {
     struct sockaddr_ll dest;
     struct ip_udp_dhcp_packet packet;
@@ -169,3 +171,122 @@ int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
   out:
     return result;
 }
+
+static void init_selecting_packet(struct client_state_t *cs,
+                                  struct dhcpMessage *packet,
+                                  unsigned char *message)
+{
+    unsigned char *temp = NULL;
+    /* Must be a DHCPOFFER to one of our xid's */
+    if (*message == DHCPOFFER) {
+        if ((temp = get_option(packet, DHCP_SERVER_ID))) {
+            /* Memcpy to a temp buffer to force alignment */
+            memcpy(&cs->serverAddr, temp, 4);
+            cs->xid = packet->xid;
+            cs->requestedIP = packet->yiaddr;
+
+            /* enter requesting state */
+            cs->dhcpState = DS_REQUESTING;
+            cs->timeout = 0;
+            cs->packetNum = 0;
+        } else {
+            log_line("No server ID in message");
+        }
+    }
+}
+
+// from ndhc.c
+void change_listen_mode(int new_mode);
+void arp_check(struct dhcpMessage *packet);
+
+static void dhcp_ack_or_nak_packet(struct client_state_t *cs,
+                                   struct dhcpMessage *packet,
+                                   unsigned char *message)
+{
+    unsigned char *temp = NULL;
+    if (*message == DHCPACK) {
+        if (!(temp = get_option(packet, DHCP_LEASE_TIME))) {
+            log_line("No lease time received, assuming 1h.");
+            cs->lease = 60 * 60;
+        } else {
+            /* Memcpy to a temp buffer to force alignment */
+            memcpy(&cs->lease, temp, 4);
+            cs->lease = ntohl(cs->lease);
+            /* Enforce upper and lower bounds on lease. */
+            cs->lease &= 0x0fffffff;
+            if (cs->lease < RETRY_DELAY)
+                cs->lease = RETRY_DELAY;
+        }
+
+        arp_check(packet);
+        // Can transition from DS_ARP_CHECK to DS_BOUND or DS_INIT_SELECTING.
+
+    } else if (*message == DHCPNAK) {
+        /* return to init state */
+        log_line("Received DHCP NAK.");
+        run_script(packet, SCRIPT_NAK);
+        if (cs->dhcpState != DS_REQUESTING)
+            run_script(NULL, SCRIPT_DECONFIG);
+        cs->dhcpState = DS_INIT_SELECTING;
+        cs->timeout = 0;
+        cs->requestedIP = 0;
+        cs->packetNum = 0;
+        change_listen_mode(LM_RAW);
+        // XXX: this isn't rfc compliant: should be exp backoff
+        sleep(3); /* avoid excessive network traffic */
+    }
+}
+
+void handle_packet(struct client_state_t *cs)
+{
+    unsigned char *message = NULL;
+    int len;
+    struct dhcpMessage packet;
+
+    if (cs->listenMode == LM_KERNEL)
+        len = get_packet(&packet, cs->listenFd);
+    else if (cs->listenMode == LM_RAW)
+        len = get_raw_packet(&packet, cs->listenFd);
+    else /* LM_NONE */
+        return;
+
+    if (len == -1 && errno != EINTR) {
+        log_error("reopening socket.");
+        change_listen_mode(cs->listenMode); /* just close and reopen */
+    }
+
+    if (len < 0)
+        return;
+
+    if (packet.xid != cs->xid) {
+        log_line("Ignoring XID %lx (our xid is %lx).",
+                 (uint32_t) packet.xid, cs->xid);
+        return;
+    }
+
+    if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
+        log_line("couldnt get option from packet -- ignoring");
+        return;
+    }
+
+    switch (cs->dhcpState) {
+        case DS_INIT_SELECTING:
+            init_selecting_packet(cs, &packet, message);
+            break;
+        case DS_ARP_CHECK:
+            /* We ignore dhcp packets for now.  This state will
+             * be changed by the callback for arp ping.
+             */
+            break;
+        case DS_RENEW_REQUESTED:
+        case DS_REQUESTING:
+        case DS_RENEWING:
+        case DS_REBINDING:
+            dhcp_ack_or_nak_packet(cs, &packet, message);
+            break;
+        case DS_BOUND:
+        case DS_RELEASED:
+        default:
+            break;
+    }
+}

ndhc/packet.h

@@ -4,6 +4,8 @@
 #include <netinet/udp.h>
 #include <netinet/ip.h>
 
+#include "config.h"
+
 struct dhcpMessage {
     uint8_t op;
     uint8_t htype;
@@ -52,5 +54,5 @@ int raw_packet(struct dhcpMessage *payload, uint32_t source_ip,
                unsigned char *dest_arp, int ifindex);
 int kernel_packet(struct dhcpMessage *payload, uint32_t source_ip,
                   int source_port, uint32_t dest_ip, int dest_port);
-
+void handle_packet(struct client_state_t *cs);
 #endif