Various user-provided patches

Makefile

@@ -8,12 +8,15 @@ all:	dhcpd dhclient
 
 .include <bsd.prog.mk>
 
-CFLAGS += -g -Wall -Wstrict-prototypes -Wno-unused \
+DEBUG=-g
+
+CFLAGS += $(DEBUG) -Wall -Wstrict-prototypes -Wno-unused \
+	  -Wno-implicit -Wno-comment \
 	  -Wno-uninitialized -Werror
 
 dhclient:	dhclient.o confpars.o alloc.o memory.o options.o \
 		hash.o tables.o inet.o convert.o conflex.o errwarn.o \
 		tree.o print.o db.o
-	cc -o dhclient dhclient.o confpars.o alloc.o memory.o options.o \
+	$(CC) -o dhclient dhclient.o confpars.o alloc.o memory.o options.o \
 		hash.o tables.o inet.o convert.o conflex.o errwarn.o \
 		print.o tree.o db.o

Makefile.std

@@ -11,7 +11,7 @@ DEBUG=-g
 CFLAGS=$(DEBUG)
 
 dhcpd:	$(OBJS) $(COBJ)
-	cc -o dhcpd $(OBJS) $(COBJ)
+	$(CC) -o dhcpd $(OBJS) $(COBJ)
 
 dhclient:	dhclient.o $(COBJ)
-	cc -o dhclient dhclient.o $(COBJ)
+	$(CC) -o dhclient dhclient.o $(COBJ)

README

@@ -32,6 +32,26 @@ Bakeoff participants at Connectathon who tried their clients against
 dhcpd and told me where it was busted, or, later on, that it wasn't
 busted anymore.
 
+			      DEBUGGING
+
+dhcpd logs to LOG_DAEMON.   Depending on the logging level that you
+choose with syslog, you can get quite a bit of information about what
+dhcpd is doing.   To get the most logging, put the following in your
+/etc/syslog.conf file and restart syslog:
+
+daemon.debug:	/var/log/daemon.log
+
+(obviously, change the filename to suit your taste).
+
+This change may have the unfortunate side effect of capturing a lot of
+information from daemons other than dhcpd that you don't want to look
+at.
+
+You can also compile dhcpd with ``make DEBUG="-g -DDEBUG"''.  If you
+do this, dhcpd will run in the foreground rather than as a daemon, and
+will print its log messages to standard error.  It will also dump the
+contents of all packets it receives and sends.
+
 				 BUGS
 
 Currently, ISC dhcpd supports the DHCP protocol strictly the standard

bootp.c

@@ -151,8 +151,11 @@ void bootp (packet)
 #endif
 	memset (to.sin_zero, 0, sizeof to.sin_zero);
 
-	note ("Sending bootp reply to %s, port %d",
-	      inet_ntoa (to.sin_addr), to.sin_port);
+	note ("Sending BOOTREPLY to %s, address %s",
+	      print_hw_addr (packet -> raw -> htype,
+			     packet -> raw -> hlen,
+			     packet -> raw -> chaddr),
+	      inet_ntoa (packet -> raw -> yiaddr));
 
 	errno = 0;
 	result = sendto (packet -> client_sock, &raw, outgoing.packet_length,

cf/bsdos.h

@@ -1,6 +1,6 @@
-/* netbsd.h
+/* bsdos.h
 
-   System dependencies for NetBSD... */
+   System dependencies for BSDI BSD/OS... */
 
 /*
  * Copyright (c) 1996 The Internet Software Consortium.  All rights reserved.

common/conflex.c

@@ -106,7 +106,7 @@ static int get_token (cfile)
 			ttok = read_string (cfile);
 			break;
 		}
-		if (isascii (c) && isdigit (c)) {
+		if ((isascii (c) && isdigit (c)) || c == '-') {
 			ttok = read_number (c, cfile);
 			break;
 		} else if (isascii (c) && isalpha (c)) {

common/options.c

@@ -173,12 +173,15 @@ void cons_options (inpacket, outpacket, options, overload)
 	/* XXX Maybe it would be safe to assume that we can send a packet
 	   to the client that's as big as the one it sent us, even if it
 	   didn't specify a large MTU. */
-	if (inpacket && inpacket -> options [DHO_DHCP_MAX_MESSAGE_SIZE].data)
+	if (inpacket && inpacket -> options [DHO_DHCP_MAX_MESSAGE_SIZE].data) {
 		main_buffer_size =
 			(getUShort (inpacket -> options
 				    [DHO_DHCP_MAX_MESSAGE_SIZE].data)
 			 - DHCP_FIXED_LEN);
-	else
+		/* Enforce a minimum packet size... */
+		if (main_buffer_size < (576 - DHCP_FIXED_LEN))
+			main_buffer_size = 576 - DHCP_FIXED_LEN;
+	} else
 		main_buffer_size = 576 - DHCP_FIXED_LEN;
 
 	/* Preload the option priority list with mandatory options. */

common/socket.c

@@ -48,6 +48,27 @@ static char copyright[] =
 #include "dhcpd.h"
 #include <sys/ioctl.h>
 
+#ifdef USE_BPF
+
+#include <net/bpf.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <net/if_dl.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+#include <netinet/if_ether.h>
+
+struct interface {
+	struct in_addr	address;
+	int		bpf;
+};
+
+static struct interface *if_list;
+static int num_ifaces;
+
+#endif
+
 /* List of sockets we're accepting packets on... */
 struct socklist {
 	struct socklist *next;
@@ -86,17 +107,48 @@ u_int32_t *get_interface_list (count)
 	   second time to copy them into an array of addresses. */
 	for (i = 0; i < ic.ifc_len;) {
 		struct ifreq *ifp = (struct ifreq *)((caddr_t)ic.ifc_req + i);
+#ifdef HAVE_SIN_LEN
 		i += (sizeof ifp -> ifr_name) + ifp -> ifr_addr.sa_len;
+#else
+		i += sizeof *ifp;
+#endif
 		if (ifp -> ifr_addr.sa_family == AF_INET) {
 			struct sockaddr_in *foo =
 				(struct sockaddr_in *)(&ifp -> ifr_addr);
 			/* We don't want the loopback interface. */
 			if (foo -> sin_addr.s_addr == INADDR_LOOPBACK)
 				continue;
-			if (intbuf)
-				intbuf [ifix++] = foo -> sin_addr.s_addr;
-			else
+			if (intbuf) {
+				intbuf [ifix] = foo -> sin_addr.s_addr;
+#ifdef USE_BPF
+				/* Open a bpf device for this interface */
+				{
+				  int b;
+				  char filename[50];
+
+				  for (b = 0; 1; b++)
+				  {
+				    snprintf(filename, sizeof(filename),
+				      "/dev/bpf%d", b);
+				    if ((if_list[ifix].bpf =
+					open(filename, O_RDWR, 0)) < 0)
+				      if (errno == EBUSY)
+					continue;
+				      else
+					error ("Can't find free bpf: %m");
+				    else
+				      break;
+				  }
+				  if (ioctl(if_list[ifix].bpf,
+				      BIOCSETIF, ifp) < 0)
+				    error ("Can't BIOCSETIF on bpf: %m");
+				}
+				if_list[ifix].address = foo->sin_addr;
+#endif
+				ifix++;
+			} else {
 				++ifcount;
+			}
 		}
 	}
 	/* If we haven't already filled our array, allocate it and go
@@ -107,6 +159,13 @@ u_int32_t *get_interface_list (count)
 					       "get_interface_list");
 		if (!intbuf)
 			return intbuf;
+#ifdef USE_BPF
+		num_ifaces = ifcount;
+		if (!(if_list = (struct interface *)dmalloc
+					(num_ifaces * sizeof(*if_list),
+					"get_interface_list")))
+			error ("Can't allocate memory for if_list");
+#endif
 		goto again;
 	}
 	*count = ifcount;
@@ -215,3 +274,198 @@ void dispatch ()
 	} while (1);
 }
 
+#ifndef USE_BPF
+
+int sendpkt (packet, raw, len, to, tolen)
+	struct packet *packet;
+	struct dhcp_packet *raw;
+	size_t len;
+	struct sockaddr *to;
+	int tolen;
+{
+	return(sendto(packet->client_sock, raw, len, 0, to, tolen));
+}
+
+#else
+
+static void		IpChecksum(struct ip *ip);
+static void		UdpChecksum(struct ip *ip);
+static u_int32_t	Checksum(u_int16_t *buf, int nwords);
+
+struct raw_packet
+{
+  u_int16_t space;
+  struct ether_header en_hdr;
+  struct ip ip;
+  struct udphdr udp;
+  struct dhcp_packet dhcp;
+};
+
+int sendpkt (in_packet, raw, len, to, tolen)
+  struct packet *in_packet;
+  struct dhcp_packet *raw;
+  size_t len;
+  struct sockaddr *to;
+  int tolen;
+{
+  int			i, k;
+  struct iaddr		dest;
+  struct subnet		*subnet;
+  struct raw_packet	out_packet;
+  struct raw_packet	*const pkt = &out_packet;
+
+/* Find local subnet, or else forward to gateway */
+
+  dest.len = 4;
+  memcpy(&dest.iabuf, &((struct sockaddr_in *) to)->sin_addr, dest.len);
+  if ((subnet = find_subnet(dest)) == NULL)
+    return(sendto(in_packet->client_sock, raw, len, 0, to, tolen));
+
+/* Find interface corresponding to subnet */
+
+  for (i = 0; i < num_ifaces; i++)
+  {
+    for (k = 0; k < subnet->net.len
+      && (dest.iabuf[k] & subnet->netmask.iabuf[k])
+	== (subnet->net.iabuf[k] & subnet->netmask.iabuf[k]);
+    k++);
+    if (k == subnet->net.len)
+      break;
+  }
+  if (i == num_ifaces)
+    return(sendto(in_packet->client_sock, raw, len, 0, to, tolen));
+
+/* EtherNet header */
+
+  memset(pkt->en_hdr.ether_dhost, 0xff, sizeof(pkt->en_hdr.ether_dhost));
+  memset(pkt->en_hdr.ether_shost, 0x00, sizeof(pkt->en_hdr.ether_shost));
+  pkt->en_hdr.ether_type = ETHERTYPE_IP;
+
+/* IP header (except for checksum) */
+
+  pkt->ip.ip_v = 4;
+  pkt->ip.ip_hl = 5;
+  pkt->ip.ip_tos = IPTOS_LOWDELAY;
+  pkt->ip.ip_len = htons(sizeof(pkt->ip) + sizeof(pkt->udp) + len);
+  pkt->ip.ip_id = 0;
+  pkt->ip.ip_off = 0;
+  pkt->ip.ip_ttl = 16;
+  pkt->ip.ip_p = IPPROTO_UDP;
+  pkt->ip.ip_sum = 0;
+  pkt->ip.ip_src = if_list[i].address;
+  inet_aton("255.255.255.255", &pkt->ip.ip_dst);
+
+/* UDP header */
+
+  pkt->udp.uh_sport = htons(67);		/* XXX! */
+  pkt->udp.uh_dport = in_packet->client_port;
+  pkt->udp.uh_ulen = htons(sizeof(pkt->udp) + len);
+  pkt->udp.uh_sum = 0;
+
+/* DHCP packet */
+
+  pkt->dhcp = *raw;
+
+/* Compute checksums */
+
+  UdpChecksum(&pkt->ip);
+  IpChecksum(&pkt->ip);
+
+/* Fire it off */
+
+  if (write(if_list[i].bpf, &pkt->en_hdr,
+      ntohs(pkt->ip.ip_len) + sizeof(pkt->en_hdr)) < 0)
+    warn ("Can't deliver packet: write: %m");
+  return(0);
+}
+
+/*
+ * UdpChecksum()
+ *
+ * Recompute a UDP checksum on a packet
+ *
+ * UDP pseudo-header (prot = IPPROTO_UDP = 17):
+ *
+ *  | source IP address	       |
+ *  | dest.  IP address	       |
+ *  | zero | prot | UDP leng   |
+ *
+ */
+
+static void
+UdpChecksum(struct ip *ip)
+{
+  struct udphdr	*udp = (struct udphdr *) ((long *) ip + ip->ip_hl);
+  u_int32_t	sum;
+
+/* Pad with zero */
+
+  if (ntohs(udp->uh_ulen) & 0x1)
+    *((u_char *) udp + ntohs(udp->uh_ulen)) = 0;
+
+/* Do pseudo-header first */
+
+  sum = Checksum((u_int16_t *) &ip->ip_src, 4);
+  sum += (u_int16_t) IPPROTO_UDP;
+  sum += (u_int16_t) ntohs(udp->uh_ulen);
+
+/* Now do UDP packet itself */
+
+  udp->uh_sum = 0;
+  sum += Checksum((u_int16_t *) udp,
+	  ((u_int16_t) ntohs(udp->uh_ulen) + 1) >> 1);
+
+/* Flip it & stick it */
+
+  sum = (sum >> 16) + (sum & 0xFFFF);
+  sum += (sum >> 16);
+  sum = ~sum;
+
+  udp->uh_sum = htons(sum);
+}
+
+/*
+ * IpChecksum()
+ *
+ * Recompute an IP header checksum
+ *
+ */
+
+static void
+IpChecksum(struct ip *ip)
+{
+  u_int32_t	sum;
+
+/* Sum up IP header words */
+
+  ip->ip_sum = 0;
+  sum = Checksum((u_int16_t *) ip, ip->ip_hl * 2);
+
+/* Flip it & stick it */
+
+  sum = (sum >> 16) + (sum & 0xFFFF);
+  sum += (sum >> 16);
+  sum = ~sum;
+
+  ip->ip_sum = htons(sum);
+}
+
+/*
+ * Checksum()
+ *
+ * Do the one's complement sum thing over a range of words
+ * Ideally, this should get replaced by an assembly version.
+ */
+
+static u_int32_t
+Checksum(u_int16_t *buf, int nwords)
+{
+  u_int32_t	sum = 0;
+
+  while (nwords--)
+    sum += (u_int16_t) ntohs(*buf++);
+  return(sum);
+}
+
+#endif
+

conflex.c

@@ -106,7 +106,7 @@ static int get_token (cfile)
 			ttok = read_string (cfile);
 			break;
 		}
-		if (isascii (c) && isdigit (c)) {
+		if ((isascii (c) && isdigit (c)) || c == '-') {
 			ttok = read_number (c, cfile);
 			break;
 		} else if (isascii (c) && isalpha (c)) {

confpars.c

@@ -1024,7 +1024,7 @@ TIME parse_date (cfile, bc)
 			skip_to_semi (cfile);
 		longjmp (*bc, 1);
 	}
-	tm.tm_mon = atoi (val);
+	tm.tm_mon = atoi (val) - 1;
 
 	/* Slash seperating month from day... */
 	token = next_token (&val, cfile);
@@ -1093,9 +1093,12 @@ TIME parse_date (cfile, bc)
 	}
 	tm.tm_sec = atoi (val);
 
+#ifndef BROKEN_TM_GMT
+	/* linux does not implement these yet */
 	tm.tm_zone = "GMT";
-	tm.tm_isdst = 0;
 	tm.tm_gmtoff = 0;
+#endif
+	tm.tm_isdst = 0;
 
 	/* XXX */ /* We assume that mktime does not use tm_yday. */
 	tm.tm_yday = 0;

db.c

@@ -117,7 +117,7 @@ void new_lease_file ()
 
 	/* Make a temporary lease file... */
 	time (&t);
-	sprintf (newfname, "%s.%d", _PATH_DHCPD_DB, t & 32767);
+	sprintf (newfname, "%s.%d", _PATH_DHCPD_DB, (int) (t & 32767));
 	if ((db_file = fopen (newfname, "w")) == NULL) {
 		error ("Can't start new lease file: %m");
 	}

dhcp.c

@@ -83,6 +83,11 @@ void dhcpdiscover (packet)
 {
 	struct lease *lease = find_lease (packet);
 
+	debug ("Received DHCPDISCOVER from %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr));
+
 	/* If we didn't find a lease, try to allocate one... */
 	if (!lease) {
 		lease = packet -> subnet -> last_lease;
@@ -106,17 +111,29 @@ void dhcprequest (packet)
 	struct lease *lease = find_lease (packet);
 	struct iaddr cip;
 
-	/* If a client on our local network wants to renew a lease on
-	   an address off our local network, NAK it. */
 	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
 		cip.len = 4;
 		memcpy (cip.iabuf,
 			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
 			4);
+	} else {
+		cip.len = 4;
+		memcpy (cip.iabuf, &packet -> raw -> ciaddr.s_addr, 4);
+	}
+
+	debug ("Received DHCPREQUEST from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       piaddr (cip));
+
+	/* If a client on our local network wants to renew a lease on
+	   an address off our local network, NAK it. */
+	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
 		if (!addr_eq (packet -> subnet -> net,
 			      subnet_number (cip,
 					     packet -> subnet -> netmask))) {
-			nak_lease (packet);
+			nak_lease (packet, &cip);
 			return;
 		}
 	}
@@ -127,7 +144,7 @@ void dhcprequest (packet)
 		if (!addr_eq (packet -> subnet -> net,
 			      subnet_number (cip,
 					     packet -> subnet -> netmask))) {
-			nak_lease (packet);
+			nak_lease (packet, &cip);
 			return;
 		}
 	}
@@ -149,7 +166,7 @@ void dhcprequest (packet)
 
 	/* If we didn't find a lease, don't try to allocate one... */
 	if (!lease) {
-		nak_lease (packet);
+		nak_lease (packet, &cip);
 		return;
 	}
 
@@ -161,6 +178,12 @@ void dhcprelease (packet)
 {
 	struct lease *lease = find_lease (packet);
 
+	debug ("Received DHCPRELEASE from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       inet_ntoa (packet -> raw -> ciaddr));
+
 	/* If we found a lease, release it. */
 	if (lease) {
 		release_lease (lease);
@@ -171,6 +194,22 @@ void dhcpdecline (packet)
 	struct packet *packet;
 {
 	struct lease *lease = find_lease (packet);
+	struct iaddr cip;
+
+	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
+		cip.len = 4;
+		memcpy (cip.iabuf,
+			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
+			4);
+	} else {
+		cip.len = 0;
+	}
+
+	debug ("Received DHCPDECLINE from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       piaddr (cip));
 
 	/* If we found a lease, mark it as unusable and complain. */
 	if (lease) {
@@ -181,10 +220,17 @@ void dhcpdecline (packet)
 void dhcpinform (packet)
 	struct packet *packet;
 {
+	debug ("Received DHCPINFORM from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       inet_ntoa (packet -> raw -> ciaddr));
+
 }
 
-void nak_lease (packet)
+void nak_lease (packet, cip)
 	struct packet *packet;
+	struct iaddr *cip;
 {
 	struct sockaddr_in to;
 	int result;
@@ -244,8 +290,8 @@ void nak_lease (packet)
 		to.sin_addr = raw.giaddr;
 		to.sin_port = server_port;
 	} else {
-		to.sin_addr.s_addr = INADDR_BROADCAST;
-		to.sin_port = htons (ntohs (server_port) + 1); /* XXX */
+		memcpy (&to.sin_addr.s_addr, cip->iabuf, 4);
+		to.sin_port = packet->client_port;
 	}
 
 	to.sin_family = AF_INET;
@@ -254,14 +300,17 @@ void nak_lease (packet)
 #endif
 	memset (to.sin_zero, 0, sizeof to.sin_zero);
 
-	note ("Sending dhcp NAK to %s, port %d",
+	note ("Sending DHCPNAK to %s at IP address %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
 	      inet_ntoa (to.sin_addr), htons (to.sin_port));
 
 	errno = 0;
-	result = sendto (packet -> client_sock, &raw, outgoing.packet_length,
-			 0, (struct sockaddr *)&to, sizeof to);
+	result = sendpkt (packet, &raw, outgoing.packet_length,
+				(struct sockaddr *) &to, sizeof(to));
 	if (result < 0)
-		warn ("sendto: %m");
+		warn ("sendpkt: %m");
 
 #ifdef DEBUG
 	dump_packet (packet);
@@ -471,6 +520,15 @@ void ack_lease (packet, lease, offer, when)
 		options [DHO_DHCP_USER_CLASS_ID] -> tree = (struct tree *)0;
 	}
 
+	/* Sanity check the lease time. */
+ 	if ((lease->offered_expiry - cur_time) < 0)
+ 		putULong(lease_time_buf, packet->subnet->default_lease_time);
+ 	else if (lease -> offered_expiry - cur_time >
+		 packet -> subnet -> max_lease_time) 
+ 		putULong (lease_time_buf, packet -> subnet -> max_lease_time);
+	else 
+		putULong(lease_time_buf, lease -> offered_expiry - cur_time);
+
 	putULong (lease_time_buf, lease -> offered_expiry - cur_time);
 	options [DHO_DHCP_LEASE_TIME] = &lease_time_tree;
 	options [DHO_DHCP_LEASE_TIME] -> value = lease_time_buf;
@@ -508,7 +566,7 @@ void ack_lease (packet, lease, offer, when)
 
 	/* Otherwise, broadcast it on the local network. */
 	} else {
-		to.sin_addr.s_addr = INADDR_BROADCAST;
+		memcpy (&to.sin_addr.s_addr, lease -> ip_addr.iabuf, 4);
 		to.sin_port = htons (ntohs (server_port) + 1); /* XXX */
 	}
 
@@ -518,14 +576,18 @@ void ack_lease (packet, lease, offer, when)
 #endif
 	memset (to.sin_zero, 0, sizeof to.sin_zero);
 
-	note ("Sending dhcp reply to %s, port %d",
+	note ("Sending %s to %s at IP address %s",
+	      offer == DHCPACK ? "DHCPACK" : "DHCPOFFER",
+	      print_hw_addr (packet -> raw -> htype,
+			     packet -> raw -> hlen,
+			     packet -> raw -> chaddr),
 	      inet_ntoa (to.sin_addr), htons (to.sin_port));
 
 	errno = 0;
-	result = sendto (packet -> client_sock, &raw, outgoing.packet_length,
-			 0, (struct sockaddr *)&to, sizeof to);
+	result = sendpkt (packet, &raw, outgoing.packet_length,
+				(struct sockaddr *) &to, sizeof(to));
 	if (result < 0)
-		warn ("sendto: %m");
+		warn ("sendpkt: %m");
 
 #ifdef DEBUG
 	dump_packet (packet);

dhcpd.c

@@ -179,9 +179,9 @@ int main (argc, argv, envp)
 	}
 
 	/* Write a pid file. */
-	if ((i = open (_PATH_DHCPD_PID, O_WRONLY | O_CREAT)) >= 0) {
+	if ((i = open (_PATH_DHCPD_PID, O_WRONLY | O_CREAT, 0640)) >= 0) {
 		char obuf [20];
-		sprintf (obuf, "%d\n", getpid ());
+		sprintf (obuf, "%d\n", (int)getpid ());
 		write (i, obuf, strlen (obuf));
 		close (i);
 	}

dhcpd.h

@@ -54,9 +54,9 @@
 #include <ctype.h>
 #include <time.h>
 
+#include "osdep.h"
 #include "dhcp.h"
 #include "cdefs.h"
-#include "osdep.h"
 #include "tree.h"
 #include "hash.h"
 #include "inet.h"
@@ -150,14 +150,21 @@ typedef unsigned char option_mask [16];
 #define OPTION_SPACE(x)		((x) + 2 * ((x) / 255 + 1))
 
 /* Default path to dhcpd config file. */
-#ifndef _PATH_DHCPD_CONF
 #ifdef DEBUG
 #define _PATH_DHCPD_CONF	"dhcpd.conf"
 #define _PATH_DHCPD_DB		"dhcpd.leases"
 #else
+#ifndef _PATH_DHCPD_CONF
 #define _PATH_DHCPD_CONF	"/etc/dhcpd.conf"
+#endif
+
+#ifndef _PATH_DHCPD_DB
 #define _PATH_DHCPD_DB		"/etc/dhcpd.leases"
 #endif
+
+#ifndef _PATH_DHCPD_PID
+#define _PATH_DHCPD_PID		"/var/run/dhcpd.pid"
+#endif
 #endif
 
 #define MAX_TIME 0x7fffffff
@@ -252,7 +259,7 @@ void dhcprequest PROTO ((struct packet *));
 void dhcprelease PROTO ((struct packet *));
 void dhcpdecline PROTO ((struct packet *));
 void dhcpinform PROTO ((struct packet *));
-void nak_lease PROTO ((struct packet *));
+void nak_lease PROTO ((struct packet *, struct iaddr *cip));
 void ack_lease PROTO ((struct packet *, struct lease *, unsigned char, TIME));
 struct lease *find_lease PROTO ((struct packet *));
 
@@ -309,8 +316,11 @@ void dump_raw PROTO ((unsigned char *, int));
 
 /* socket.c */
 u_int32_t *get_interface_list PROTO ((int *));
+char *get_interface PROTO ((u_int32_t));
 void listen_on PROTO ((u_int16_t, u_int32_t));
 void dispatch PROTO ((void));
+int sendpkt PROTO ((struct packet *, struct dhcp_packet *,
+			size_t, struct sockaddr *, int));
 
 /* hash.c */
 struct hash_table *new_hash PROTO ((void));

includes/cf/bsdos.h

@@ -1,6 +1,6 @@
-/* netbsd.h
+/* bsdos.h
 
-   System dependencies for NetBSD... */
+   System dependencies for BSDI BSD/OS... */
 
 /*
  * Copyright (c) 1996 The Internet Software Consortium.  All rights reserved.

includes/dhcpd.h

@@ -54,9 +54,9 @@
 #include <ctype.h>
 #include <time.h>
 
+#include "osdep.h"
 #include "dhcp.h"
 #include "cdefs.h"
-#include "osdep.h"
 #include "tree.h"
 #include "hash.h"
 #include "inet.h"
@@ -150,14 +150,21 @@ typedef unsigned char option_mask [16];
 #define OPTION_SPACE(x)		((x) + 2 * ((x) / 255 + 1))
 
 /* Default path to dhcpd config file. */
-#ifndef _PATH_DHCPD_CONF
 #ifdef DEBUG
 #define _PATH_DHCPD_CONF	"dhcpd.conf"
 #define _PATH_DHCPD_DB		"dhcpd.leases"
 #else
+#ifndef _PATH_DHCPD_CONF
 #define _PATH_DHCPD_CONF	"/etc/dhcpd.conf"
+#endif
+
+#ifndef _PATH_DHCPD_DB
 #define _PATH_DHCPD_DB		"/etc/dhcpd.leases"
 #endif
+
+#ifndef _PATH_DHCPD_PID
+#define _PATH_DHCPD_PID		"/var/run/dhcpd.pid"
+#endif
 #endif
 
 #define MAX_TIME 0x7fffffff
@@ -252,7 +259,7 @@ void dhcprequest PROTO ((struct packet *));
 void dhcprelease PROTO ((struct packet *));
 void dhcpdecline PROTO ((struct packet *));
 void dhcpinform PROTO ((struct packet *));
-void nak_lease PROTO ((struct packet *));
+void nak_lease PROTO ((struct packet *, struct iaddr *cip));
 void ack_lease PROTO ((struct packet *, struct lease *, unsigned char, TIME));
 struct lease *find_lease PROTO ((struct packet *));
 
@@ -309,8 +316,11 @@ void dump_raw PROTO ((unsigned char *, int));
 
 /* socket.c */
 u_int32_t *get_interface_list PROTO ((int *));
+char *get_interface PROTO ((u_int32_t));
 void listen_on PROTO ((u_int16_t, u_int32_t));
 void dispatch PROTO ((void));
+int sendpkt PROTO ((struct packet *, struct dhcp_packet *,
+			size_t, struct sockaddr *, int));
 
 /* hash.c */
 struct hash_table *new_hash PROTO ((void));

includes/osdep.h

@@ -48,3 +48,19 @@
 #include "cf/netbsd.h"
 #endif
 
+#ifdef __FreeBSD__
+#include "cf/freebsd.h"
+#endif
+
+#ifdef sun
+#include "cf/sunos4.h"
+#endif
+
+
+#ifdef ultrix
+#include "cf/ultrix.h"
+#endif
+
+#ifdef linux
+#include "cf/linux.h"
+#endif

options.c

@@ -173,12 +173,15 @@ void cons_options (inpacket, outpacket, options, overload)
 	/* XXX Maybe it would be safe to assume that we can send a packet
 	   to the client that's as big as the one it sent us, even if it
 	   didn't specify a large MTU. */
-	if (inpacket && inpacket -> options [DHO_DHCP_MAX_MESSAGE_SIZE].data)
+	if (inpacket && inpacket -> options [DHO_DHCP_MAX_MESSAGE_SIZE].data) {
 		main_buffer_size =
 			(getUShort (inpacket -> options
 				    [DHO_DHCP_MAX_MESSAGE_SIZE].data)
 			 - DHCP_FIXED_LEN);
-	else
+		/* Enforce a minimum packet size... */
+		if (main_buffer_size < (576 - DHCP_FIXED_LEN))
+			main_buffer_size = 576 - DHCP_FIXED_LEN;
+	} else
 		main_buffer_size = 576 - DHCP_FIXED_LEN;
 
 	/* Preload the option priority list with mandatory options. */

osdep.h

@@ -48,3 +48,19 @@
 #include "cf/netbsd.h"
 #endif
 
+#ifdef __FreeBSD__
+#include "cf/freebsd.h"
+#endif
+
+#ifdef sun
+#include "cf/sunos4.h"
+#endif
+
+
+#ifdef ultrix
+#include "cf/ultrix.h"
+#endif
+
+#ifdef linux
+#include "cf/linux.h"
+#endif

server/bootp.c

@@ -151,8 +151,11 @@ void bootp (packet)
 #endif
 	memset (to.sin_zero, 0, sizeof to.sin_zero);
 
-	note ("Sending bootp reply to %s, port %d",
-	      inet_ntoa (to.sin_addr), to.sin_port);
+	note ("Sending BOOTREPLY to %s, address %s",
+	      print_hw_addr (packet -> raw -> htype,
+			     packet -> raw -> hlen,
+			     packet -> raw -> chaddr),
+	      inet_ntoa (packet -> raw -> yiaddr));
 
 	errno = 0;
 	result = sendto (packet -> client_sock, &raw, outgoing.packet_length,

server/confpars.c

@@ -1024,7 +1024,7 @@ TIME parse_date (cfile, bc)
 			skip_to_semi (cfile);
 		longjmp (*bc, 1);
 	}
-	tm.tm_mon = atoi (val);
+	tm.tm_mon = atoi (val) - 1;
 
 	/* Slash seperating month from day... */
 	token = next_token (&val, cfile);
@@ -1093,9 +1093,12 @@ TIME parse_date (cfile, bc)
 	}
 	tm.tm_sec = atoi (val);
 
+#ifndef BROKEN_TM_GMT
+	/* linux does not implement these yet */
 	tm.tm_zone = "GMT";
-	tm.tm_isdst = 0;
 	tm.tm_gmtoff = 0;
+#endif
+	tm.tm_isdst = 0;
 
 	/* XXX */ /* We assume that mktime does not use tm_yday. */
 	tm.tm_yday = 0;

server/db.c

@@ -117,7 +117,7 @@ void new_lease_file ()
 
 	/* Make a temporary lease file... */
 	time (&t);
-	sprintf (newfname, "%s.%d", _PATH_DHCPD_DB, t & 32767);
+	sprintf (newfname, "%s.%d", _PATH_DHCPD_DB, (int) (t & 32767));
 	if ((db_file = fopen (newfname, "w")) == NULL) {
 		error ("Can't start new lease file: %m");
 	}

server/dhcp.c

@@ -83,6 +83,11 @@ void dhcpdiscover (packet)
 {
 	struct lease *lease = find_lease (packet);
 
+	debug ("Received DHCPDISCOVER from %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr));
+
 	/* If we didn't find a lease, try to allocate one... */
 	if (!lease) {
 		lease = packet -> subnet -> last_lease;
@@ -106,17 +111,29 @@ void dhcprequest (packet)
 	struct lease *lease = find_lease (packet);
 	struct iaddr cip;
 
-	/* If a client on our local network wants to renew a lease on
-	   an address off our local network, NAK it. */
 	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
 		cip.len = 4;
 		memcpy (cip.iabuf,
 			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
 			4);
+	} else {
+		cip.len = 4;
+		memcpy (cip.iabuf, &packet -> raw -> ciaddr.s_addr, 4);
+	}
+
+	debug ("Received DHCPREQUEST from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       piaddr (cip));
+
+	/* If a client on our local network wants to renew a lease on
+	   an address off our local network, NAK it. */
+	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
 		if (!addr_eq (packet -> subnet -> net,
 			      subnet_number (cip,
 					     packet -> subnet -> netmask))) {
-			nak_lease (packet);
+			nak_lease (packet, &cip);
 			return;
 		}
 	}
@@ -127,7 +144,7 @@ void dhcprequest (packet)
 		if (!addr_eq (packet -> subnet -> net,
 			      subnet_number (cip,
 					     packet -> subnet -> netmask))) {
-			nak_lease (packet);
+			nak_lease (packet, &cip);
 			return;
 		}
 	}
@@ -149,7 +166,7 @@ void dhcprequest (packet)
 
 	/* If we didn't find a lease, don't try to allocate one... */
 	if (!lease) {
-		nak_lease (packet);
+		nak_lease (packet, &cip);
 		return;
 	}
 
@@ -161,6 +178,12 @@ void dhcprelease (packet)
 {
 	struct lease *lease = find_lease (packet);
 
+	debug ("Received DHCPRELEASE from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       inet_ntoa (packet -> raw -> ciaddr));
+
 	/* If we found a lease, release it. */
 	if (lease) {
 		release_lease (lease);
@@ -171,6 +194,22 @@ void dhcpdecline (packet)
 	struct packet *packet;
 {
 	struct lease *lease = find_lease (packet);
+	struct iaddr cip;
+
+	if (packet -> options [DHO_DHCP_REQUESTED_ADDRESS].len) {
+		cip.len = 4;
+		memcpy (cip.iabuf,
+			packet -> options [DHO_DHCP_REQUESTED_ADDRESS].data,
+			4);
+	} else {
+		cip.len = 0;
+	}
+
+	debug ("Received DHCPDECLINE from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       piaddr (cip));
 
 	/* If we found a lease, mark it as unusable and complain. */
 	if (lease) {
@@ -181,10 +220,17 @@ void dhcpdecline (packet)
 void dhcpinform (packet)
 	struct packet *packet;
 {
+	debug ("Received DHCPINFORM from %s for %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
+	       inet_ntoa (packet -> raw -> ciaddr));
+
 }
 
-void nak_lease (packet)
+void nak_lease (packet, cip)
 	struct packet *packet;
+	struct iaddr *cip;
 {
 	struct sockaddr_in to;
 	int result;
@@ -244,8 +290,8 @@ void nak_lease (packet)
 		to.sin_addr = raw.giaddr;
 		to.sin_port = server_port;
 	} else {
-		to.sin_addr.s_addr = INADDR_BROADCAST;
-		to.sin_port = htons (ntohs (server_port) + 1); /* XXX */
+		memcpy (&to.sin_addr.s_addr, cip->iabuf, 4);
+		to.sin_port = packet->client_port;
 	}
 
 	to.sin_family = AF_INET;
@@ -254,14 +300,17 @@ void nak_lease (packet)
 #endif
 	memset (to.sin_zero, 0, sizeof to.sin_zero);
 
-	note ("Sending dhcp NAK to %s, port %d",
+	note ("Sending DHCPNAK to %s at IP address %s",
+	       print_hw_addr (packet -> raw -> htype,
+			      packet -> raw -> hlen,
+			      packet -> raw -> chaddr),
 	      inet_ntoa (to.sin_addr), htons (to.sin_port));
 
 	errno = 0;
-	result = sendto (packet -> client_sock, &raw, outgoing.packet_length,
-			 0, (struct sockaddr *)&to, sizeof to);
+	result = sendpkt (packet, &raw, outgoing.packet_length,
+				(struct sockaddr *) &to, sizeof(to));
 	if (result < 0)
-		warn ("sendto: %m");
+		warn ("sendpkt: %m");
 
 #ifdef DEBUG
 	dump_packet (packet);
@@ -471,6 +520,15 @@ void ack_lease (packet, lease, offer, when)
 		options [DHO_DHCP_USER_CLASS_ID] -> tree = (struct tree *)0;
 	}
 
+	/* Sanity check the lease time. */
+ 	if ((lease->offered_expiry - cur_time) < 0)
+ 		putULong(lease_time_buf, packet->subnet->default_lease_time);
+ 	else if (lease -> offered_expiry - cur_time >
+		 packet -> subnet -> max_lease_time) 
+ 		putULong (lease_time_buf, packet -> subnet -> max_lease_time);
+	else 
+		putULong(lease_time_buf, lease -> offered_expiry - cur_time);
+
 	putULong (lease_time_buf, lease -> offered_expiry - cur_time);
 	options [DHO_DHCP_LEASE_TIME] = &lease_time_tree;
 	options [DHO_DHCP_LEASE_TIME] -> value = lease_time_buf;
@@ -508,7 +566,7 @@ void ack_lease (packet, lease, offer, when)
 
 	/* Otherwise, broadcast it on the local network. */
 	} else {
-		to.sin_addr.s_addr = INADDR_BROADCAST;
+		memcpy (&to.sin_addr.s_addr, lease -> ip_addr.iabuf, 4);
 		to.sin_port = htons (ntohs (server_port) + 1); /* XXX */
 	}
 
@@ -518,14 +576,18 @@ void ack_lease (packet, lease, offer, when)
 #endif
 	memset (to.sin_zero, 0, sizeof to.sin_zero);
 
-	note ("Sending dhcp reply to %s, port %d",
+	note ("Sending %s to %s at IP address %s",
+	      offer == DHCPACK ? "DHCPACK" : "DHCPOFFER",
+	      print_hw_addr (packet -> raw -> htype,
+			     packet -> raw -> hlen,
+			     packet -> raw -> chaddr),
 	      inet_ntoa (to.sin_addr), htons (to.sin_port));
 
 	errno = 0;
-	result = sendto (packet -> client_sock, &raw, outgoing.packet_length,
-			 0, (struct sockaddr *)&to, sizeof to);
+	result = sendpkt (packet, &raw, outgoing.packet_length,
+				(struct sockaddr *) &to, sizeof(to));
 	if (result < 0)
-		warn ("sendto: %m");
+		warn ("sendpkt: %m");
 
 #ifdef DEBUG
 	dump_packet (packet);

server/dhcpd.c

@@ -179,9 +179,9 @@ int main (argc, argv, envp)
 	}
 
 	/* Write a pid file. */
-	if ((i = open (_PATH_DHCPD_PID, O_WRONLY | O_CREAT)) >= 0) {
+	if ((i = open (_PATH_DHCPD_PID, O_WRONLY | O_CREAT, 0640)) >= 0) {
 		char obuf [20];
-		sprintf (obuf, "%d\n", getpid ());
+		sprintf (obuf, "%d\n", (int)getpid ());
 		write (i, obuf, strlen (obuf));
 		close (i);
 	}

socket.c

@@ -48,6 +48,27 @@ static char copyright[] =
 #include "dhcpd.h"
 #include <sys/ioctl.h>
 
+#ifdef USE_BPF
+
+#include <net/bpf.h>
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <net/if_dl.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+#include <netinet/if_ether.h>
+
+struct interface {
+	struct in_addr	address;
+	int		bpf;
+};
+
+static struct interface *if_list;
+static int num_ifaces;
+
+#endif
+
 /* List of sockets we're accepting packets on... */
 struct socklist {
 	struct socklist *next;
@@ -86,17 +107,48 @@ u_int32_t *get_interface_list (count)
 	   second time to copy them into an array of addresses. */
 	for (i = 0; i < ic.ifc_len;) {
 		struct ifreq *ifp = (struct ifreq *)((caddr_t)ic.ifc_req + i);
+#ifdef HAVE_SIN_LEN
 		i += (sizeof ifp -> ifr_name) + ifp -> ifr_addr.sa_len;
+#else
+		i += sizeof *ifp;
+#endif
 		if (ifp -> ifr_addr.sa_family == AF_INET) {
 			struct sockaddr_in *foo =
 				(struct sockaddr_in *)(&ifp -> ifr_addr);
 			/* We don't want the loopback interface. */
 			if (foo -> sin_addr.s_addr == INADDR_LOOPBACK)
 				continue;
-			if (intbuf)
-				intbuf [ifix++] = foo -> sin_addr.s_addr;
-			else
+			if (intbuf) {
+				intbuf [ifix] = foo -> sin_addr.s_addr;
+#ifdef USE_BPF
+				/* Open a bpf device for this interface */
+				{
+				  int b;
+				  char filename[50];
+
+				  for (b = 0; 1; b++)
+				  {
+				    snprintf(filename, sizeof(filename),
+				      "/dev/bpf%d", b);
+				    if ((if_list[ifix].bpf =
+					open(filename, O_RDWR, 0)) < 0)
+				      if (errno == EBUSY)
+					continue;
+				      else
+					error ("Can't find free bpf: %m");
+				    else
+				      break;
+				  }
+				  if (ioctl(if_list[ifix].bpf,
+				      BIOCSETIF, ifp) < 0)
+				    error ("Can't BIOCSETIF on bpf: %m");
+				}
+				if_list[ifix].address = foo->sin_addr;
+#endif
+				ifix++;
+			} else {
 				++ifcount;
+			}
 		}
 	}
 	/* If we haven't already filled our array, allocate it and go
@@ -107,6 +159,13 @@ u_int32_t *get_interface_list (count)
 					       "get_interface_list");
 		if (!intbuf)
 			return intbuf;
+#ifdef USE_BPF
+		num_ifaces = ifcount;
+		if (!(if_list = (struct interface *)dmalloc
+					(num_ifaces * sizeof(*if_list),
+					"get_interface_list")))
+			error ("Can't allocate memory for if_list");
+#endif
 		goto again;
 	}
 	*count = ifcount;
@@ -215,3 +274,198 @@ void dispatch ()
 	} while (1);
 }
 
+#ifndef USE_BPF
+
+int sendpkt (packet, raw, len, to, tolen)
+	struct packet *packet;
+	struct dhcp_packet *raw;
+	size_t len;
+	struct sockaddr *to;
+	int tolen;
+{
+	return(sendto(packet->client_sock, raw, len, 0, to, tolen));
+}
+
+#else
+
+static void		IpChecksum(struct ip *ip);
+static void		UdpChecksum(struct ip *ip);
+static u_int32_t	Checksum(u_int16_t *buf, int nwords);
+
+struct raw_packet
+{
+  u_int16_t space;
+  struct ether_header en_hdr;
+  struct ip ip;
+  struct udphdr udp;
+  struct dhcp_packet dhcp;
+};
+
+int sendpkt (in_packet, raw, len, to, tolen)
+  struct packet *in_packet;
+  struct dhcp_packet *raw;
+  size_t len;
+  struct sockaddr *to;
+  int tolen;
+{
+  int			i, k;
+  struct iaddr		dest;
+  struct subnet		*subnet;
+  struct raw_packet	out_packet;
+  struct raw_packet	*const pkt = &out_packet;
+
+/* Find local subnet, or else forward to gateway */
+
+  dest.len = 4;
+  memcpy(&dest.iabuf, &((struct sockaddr_in *) to)->sin_addr, dest.len);
+  if ((subnet = find_subnet(dest)) == NULL)
+    return(sendto(in_packet->client_sock, raw, len, 0, to, tolen));
+
+/* Find interface corresponding to subnet */
+
+  for (i = 0; i < num_ifaces; i++)
+  {
+    for (k = 0; k < subnet->net.len
+      && (dest.iabuf[k] & subnet->netmask.iabuf[k])
+	== (subnet->net.iabuf[k] & subnet->netmask.iabuf[k]);
+    k++);
+    if (k == subnet->net.len)
+      break;
+  }
+  if (i == num_ifaces)
+    return(sendto(in_packet->client_sock, raw, len, 0, to, tolen));
+
+/* EtherNet header */
+
+  memset(pkt->en_hdr.ether_dhost, 0xff, sizeof(pkt->en_hdr.ether_dhost));
+  memset(pkt->en_hdr.ether_shost, 0x00, sizeof(pkt->en_hdr.ether_shost));
+  pkt->en_hdr.ether_type = ETHERTYPE_IP;
+
+/* IP header (except for checksum) */
+
+  pkt->ip.ip_v = 4;
+  pkt->ip.ip_hl = 5;
+  pkt->ip.ip_tos = IPTOS_LOWDELAY;
+  pkt->ip.ip_len = htons(sizeof(pkt->ip) + sizeof(pkt->udp) + len);
+  pkt->ip.ip_id = 0;
+  pkt->ip.ip_off = 0;
+  pkt->ip.ip_ttl = 16;
+  pkt->ip.ip_p = IPPROTO_UDP;
+  pkt->ip.ip_sum = 0;
+  pkt->ip.ip_src = if_list[i].address;
+  inet_aton("255.255.255.255", &pkt->ip.ip_dst);
+
+/* UDP header */
+
+  pkt->udp.uh_sport = htons(67);		/* XXX! */
+  pkt->udp.uh_dport = in_packet->client_port;
+  pkt->udp.uh_ulen = htons(sizeof(pkt->udp) + len);
+  pkt->udp.uh_sum = 0;
+
+/* DHCP packet */
+
+  pkt->dhcp = *raw;
+
+/* Compute checksums */
+
+  UdpChecksum(&pkt->ip);
+  IpChecksum(&pkt->ip);
+
+/* Fire it off */
+
+  if (write(if_list[i].bpf, &pkt->en_hdr,
+      ntohs(pkt->ip.ip_len) + sizeof(pkt->en_hdr)) < 0)
+    warn ("Can't deliver packet: write: %m");
+  return(0);
+}
+
+/*
+ * UdpChecksum()
+ *
+ * Recompute a UDP checksum on a packet
+ *
+ * UDP pseudo-header (prot = IPPROTO_UDP = 17):
+ *
+ *  | source IP address	       |
+ *  | dest.  IP address	       |
+ *  | zero | prot | UDP leng   |
+ *
+ */
+
+static void
+UdpChecksum(struct ip *ip)
+{
+  struct udphdr	*udp = (struct udphdr *) ((long *) ip + ip->ip_hl);
+  u_int32_t	sum;
+
+/* Pad with zero */
+
+  if (ntohs(udp->uh_ulen) & 0x1)
+    *((u_char *) udp + ntohs(udp->uh_ulen)) = 0;
+
+/* Do pseudo-header first */
+
+  sum = Checksum((u_int16_t *) &ip->ip_src, 4);
+  sum += (u_int16_t) IPPROTO_UDP;
+  sum += (u_int16_t) ntohs(udp->uh_ulen);
+
+/* Now do UDP packet itself */
+
+  udp->uh_sum = 0;
+  sum += Checksum((u_int16_t *) udp,
+	  ((u_int16_t) ntohs(udp->uh_ulen) + 1) >> 1);
+
+/* Flip it & stick it */
+
+  sum = (sum >> 16) + (sum & 0xFFFF);
+  sum += (sum >> 16);
+  sum = ~sum;
+
+  udp->uh_sum = htons(sum);
+}
+
+/*
+ * IpChecksum()
+ *
+ * Recompute an IP header checksum
+ *
+ */
+
+static void
+IpChecksum(struct ip *ip)
+{
+  u_int32_t	sum;
+
+/* Sum up IP header words */
+
+  ip->ip_sum = 0;
+  sum = Checksum((u_int16_t *) ip, ip->ip_hl * 2);
+
+/* Flip it & stick it */
+
+  sum = (sum >> 16) + (sum & 0xFFFF);
+  sum += (sum >> 16);
+  sum = ~sum;
+
+  ip->ip_sum = htons(sum);
+}
+
+/*
+ * Checksum()
+ *
+ * Do the one's complement sum thing over a range of words
+ * Ideally, this should get replaced by an assembly version.
+ */
+
+static u_int32_t
+Checksum(u_int16_t *buf, int nwords)
+{
+  u_int32_t	sum = 0;
+
+  while (nwords--)
+    sum += (u_int16_t) ntohs(*buf++);
+  return(sum);
+}
+
+#endif
+