import of dnsmasq-2.40.tar.gz

contrib/wrt/Makefile

@@ -1,7 +1,6 @@
-CFLAGS?= -O2
+CFLAGS?= -O2 -Wall -W
 
-all: dhcp_release.c
-	$(CC) $(CFLAGS) $(RPM_OPT_FLAGS) -Wall -W dhcp_release.c -o dhcp_release
+all: dhcp_release dhcp_lease_time
 
 clean:
-	rm -f *~ *.o core dhcp_release
+	rm -f *~ *.o core dhcp_release dhcp_lease_time

contrib/wrt/dhcp_lease_time.c

@@ -0,0 +1,214 @@
+/* Copyright (c) 2007 Simon Kelley
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 dated June, 1991.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+*/
+
+/* dhcp_lease_time <address> */
+
+/* Send a DHCPINFORM message to a dnsmasq server running on the local host
+   and print (to stdout) the time remaining in any lease for the given
+   address. The time is given as string printed to stdout.
+
+   If an error occurs or no lease exists for the given address, 
+   nothing is sent to stdout a message is sent to stderr and a
+   non-zero error code is returned.
+
+   Requires dnsmasq 2.40 or later. 
+*/
+
+#include <sys/types.h> 
+#include <netinet/in.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <net/if_arp.h>
+#include <sys/ioctl.h>
+#include <linux/types.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <errno.h>
+
+#define DHCP_CHADDR_MAX          16
+#define BOOTREQUEST              1
+#define DHCP_COOKIE              0x63825363
+#define OPTION_PAD               0
+#define OPTION_LEASE_TIME        51
+#define OPTION_OVERLOAD          52
+#define OPTION_MESSAGE_TYPE      53
+#define OPTION_END               255
+#define DHCPINFORM               8
+#define DHCP_SERVER_PORT         67
+
+#define option_len(opt) ((int)(((unsigned char *)(opt))[1]))
+#define option_ptr(opt) ((void *)&(((unsigned char *)(opt))[2]))
+
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+
+struct dhcp_packet {
+  u8 op, htype, hlen, hops;
+  u32 xid;
+  u16 secs, flags;
+  struct in_addr ciaddr, yiaddr, siaddr, giaddr;
+  u8 chaddr[DHCP_CHADDR_MAX], sname[64], file[128];
+  u32 cookie;
+  unsigned char options[308];
+};
+
+static unsigned char *option_find1(unsigned char *p, unsigned char *end, int opt, int minsize)
+{
+  while (*p != OPTION_END) 
+    {
+      if (p >= end)
+        return NULL; /* malformed packet */
+      else if (*p == OPTION_PAD)
+        p++;
+      else 
+        { 
+          int opt_len;
+          if (p >= end - 2)
+            return NULL; /* malformed packet */
+          opt_len = option_len(p);
+          if (p >= end - (2 + opt_len))
+            return NULL; /* malformed packet */
+          if (*p == opt && opt_len >= minsize)
+            return p;
+          p += opt_len + 2;
+        }
+    }
+  
+  return opt == OPTION_END ? p : NULL;
+}
+ 
+static unsigned char *option_find(struct dhcp_packet *mess, size_t size, int opt_type, int minsize)
+{
+  unsigned char *ret, *overload;
+  
+  /* skip over DHCP cookie; */
+  if ((ret = option_find1(&mess->options[0], ((unsigned char *)mess) + size, opt_type, minsize)))
+    return ret;
+
+  /* look for overload option. */
+  if (!(overload = option_find1(&mess->options[0], ((unsigned char *)mess) + size, OPTION_OVERLOAD, 1)))
+    return NULL;
+  
+  /* Can we look in filename area ? */
+  if ((overload[2] & 1) &&
+      (ret = option_find1(&mess->file[0], &mess->file[128], opt_type, minsize)))
+    return ret;
+
+  /* finally try sname area */
+  if ((overload[2] & 2) &&
+      (ret = option_find1(&mess->sname[0], &mess->sname[64], opt_type, minsize)))
+    return ret;
+
+  return NULL;
+}
+
+static unsigned int option_uint(unsigned char *opt, int size)
+{
+  /* this worries about unaligned data and byte order */
+  unsigned int ret = 0;
+  int i;
+  unsigned char *p = option_ptr(opt);
+  
+  for (i = 0; i < size; i++)
+    ret = (ret << 8) | *p++;
+
+  return ret;
+}
+
+int main(int argc, char **argv)
+{ 
+  struct in_addr lease;
+  struct dhcp_packet packet;
+  unsigned char *p = packet.options;
+  struct sockaddr_in dest;
+  int fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+  ssize_t rc;
+  
+  if (argc < 2)
+    { 
+      fprintf(stderr, "usage: dhcp_lease_time <address>\n");
+      exit(1);
+    }
+
+  if (fd == -1)
+    {
+      perror("cannot create socket");
+      exit(1);
+    }
+ 
+  lease.s_addr = inet_addr(argv[1]);
+   
+  memset(&packet, 0, sizeof(packet));
+ 
+  packet.hlen = 0;
+  packet.htype = 0;
+
+  packet.op = BOOTREQUEST;
+  packet.ciaddr = lease;
+  packet.cookie = htonl(DHCP_COOKIE);
+
+  *(p++) = OPTION_MESSAGE_TYPE;
+  *(p++) = 1;
+  *(p++) = DHCPINFORM;
+
+  *(p++) = OPTION_END;
+ 
+  dest.sin_family = AF_INET; 
+  dest.sin_addr.s_addr = inet_addr("127.0.0.1");
+  dest.sin_port = ntohs(DHCP_SERVER_PORT);
+  
+  if (sendto(fd, &packet, sizeof(packet), 0, 
+	     (struct sockaddr *)&dest, sizeof(dest)) == -1)
+    {
+      perror("sendto failed");
+      exit(1);
+    }
+
+  alarm(3); /* noddy timeout. */
+
+  rc = recv(fd, &packet, sizeof(packet), 0);
+  
+  if (rc < (ssize_t)(sizeof(packet) - sizeof(packet.options)))
+    {
+      perror("recv failed");
+      exit(1);
+    }
+
+  if ((p = option_find(&packet, (size_t)rc, OPTION_LEASE_TIME, 4)))
+    {
+      unsigned int t = option_uint(p, 4);
+      if (t == 0xffffffff)
+	printf("infinite");
+      else
+	{
+	  unsigned int x;
+	  if ((x = t/86400))
+	    printf("%dd", x);
+	  if ((x = (t/3600)%24))
+	    printf("%dh", x);
+	  if ((x = (t/60)%60))
+	    printf("%dm", x);
+	  if ((x = t%60))
+	    printf("%ds", x);
+	}
+      return 0;
+    }
+
+  return 1; /* no lease */
+}