1 files changed, 105 insertions, 0 deletions
diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
new file mode 100644
index 0000000..d71cd10
--- /dev/null
+++ b/networking/udhcp/arpping.c
@@ -0,0 +1,105 @@
+/*
+ * arpping.c
+ *
+ * Mostly stolen from: dhcpcd - DHCP client daemon
+ * by Yoichi Hariguchi <yoichi@fore.com>
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/if_ether.h>
+#include <net/if_arp.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "dhcpd.h"
+#include "debug.h"
+#include "arpping.h"
+
+/* args:	yiaddr - what IP to ping
+ *		ip - our ip
+ *		mac - our arp address
+ *		interface - interface to use
+ * retn: 	1 addr free
+ *		0 addr used
+ *		-1 error 
+ */  
+
+/* FIXME: match response against chaddr */
+int arpping(u_int32_t yiaddr, u_int32_t ip, unsigned char *mac, char *interface)
+{
+
+	int	timeout = 2;
+	int 	optval = 1;
+	int	s;			/* socket */
+	int	rv = 1;			/* return value */
+	struct sockaddr addr;		/* for interface name */
+	struct arpMsg	arp;
+	fd_set		fdset;
+	struct timeval	tm;
+	time_t		prevTime;
+
+
+	if ((s = socket (PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP))) == -1) {
+		LOG(LOG_ERR, "Could not open raw socket");
+		return -1;
+	}
+	
+	if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &optval, sizeof(optval)) == -1) {
+		LOG(LOG_ERR, "Could not setsocketopt on raw socket");
+		close(s);
+		return -1;
+	}
+
+	/* send arp request */
+	memset(&arp, 0, sizeof(arp));
+	memcpy(arp.ethhdr.h_dest, MAC_BCAST_ADDR, 6);	/* MAC DA */
+	memcpy(arp.ethhdr.h_source, mac, 6);		/* MAC SA */
+	arp.ethhdr.h_proto = htons(ETH_P_ARP);		/* protocol type (Ethernet) */
+	arp.htype = htons(ARPHRD_ETHER);		/* hardware type */
+	arp.ptype = htons(ETH_P_IP);			/* protocol type (ARP message) */
+	arp.hlen = 6;					/* hardware address length */
+	arp.plen = 4;					/* protocol address length */
+	arp.operation = htons(ARPOP_REQUEST);		/* ARP op code */
+	*((u_int *) arp.sInaddr) = ip;			/* source IP address */
+	memcpy(arp.sHaddr, mac, 6);			/* source hardware address */
+	*((u_int *) arp.tInaddr) = yiaddr;		/* target IP address */
+	
+	memset(&addr, 0, sizeof(addr));
+	strcpy(addr.sa_data, interface);
+	if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
+		rv = 0;
+	
+	/* wait arp reply, and check it */
+	tm.tv_usec = 0;
+	time(&prevTime);
+	while (timeout > 0) {
+		FD_ZERO(&fdset);
+		FD_SET(s, &fdset);
+		tm.tv_sec = timeout;
+		if (select(s + 1, &fdset, (fd_set *) NULL, (fd_set *) NULL, &tm) < 0) {
+			DEBUG(LOG_ERR, "Error on ARPING request: %s", strerror(errno));
+			if (errno != EINTR) rv = 0;
+		} else if (FD_ISSET(s, &fdset)) {
+			if (recv(s, &arp, sizeof(arp), 0) < 0 ) rv = 0;
+			if (arp.operation == htons(ARPOP_REPLY) && 
+			    bcmp(arp.tHaddr, mac, 6) == 0 && 
+			    *((u_int *) arp.sInaddr) == yiaddr) {
+				DEBUG(LOG_INFO, "Valid arp reply receved for this address");
+				rv = 0;
+				break;
+			}
+		}
+		timeout -= time(NULL) - prevTime;
+		time(&prevTime);
+	}
+	close(s);
+	DEBUG(LOG_INFO, "%salid arp replies for this address", rv ? "No v" : "V");	 
+	return rv;
+}