1 files changed, 105 insertions, 0 deletions

diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
new file mode 100644
index 000000000..d71cd10f4
--- /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;
+}