From a050f74bce84922f013d2e6363357373196ae8e6 Mon Sep 17 00:00:00 2001
From: "Joseph C. Lehner" <joseph.c.lehner@gmail.com>
Date: Tue, 9 Aug 2016 11:41:50 +0200
Subject: [PATCH] Create static ARP entry for device

---
 ethsock.c | 20 ++++++++++++--------
 nmrp.c    | 18 ++++++++++++++++++
 nmrpd.h   |  2 ++
 3 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/ethsock.c b/ethsock.c
index 232d84f..61e9759 100644
--- a/ethsock.c
+++ b/ethsock.c
@@ -453,7 +453,7 @@ int ethsock_arp_del(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipadd
 	return 0;
 }
 #else
-static int ethsock_arp(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipaddr, int add, int nofail)
+static int ethsock_arp(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipaddr, int add)
 {
 	DWORD ret;
 	MIB_IPNETROW arp = {
@@ -465,10 +465,14 @@ static int ethsock_arp(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ip
 	
 	memcpy(arp.bPhysAddr, hwaddr, 6);
 	
-	ret = add ? CreateIpNetEntry(&arp) : DeleteIpNetEntry(&arp);
-	if (ret != NO_ERROR && !nofail) {
-		win_perror2(add ? "CreateIpNetEntry" : "DeleteIpNetEntry", ret);
-		return -1;
+	if (add) {
+		ret = CreateIpNetEntry(&arp);
+		if (ret != NO_ERROR) {
+			win_perror2("CreateIpNetEntry", ret);
+			return -1;
+		}
+	} else {
+		DeleteIpNetEntry(&arp);
 	}
 	
 	return 0;
@@ -476,13 +480,13 @@ static int ethsock_arp(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ip
 
 int ethsock_arp_add(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipaddr)
 {
-	ethsock_arp(sock, hwaddr, ipaddr, 0, 1);
-	return ethsock_arp(sock, hwaddr, ipaddr, 1, 0);
+	ethsock_arp_del(sock, hwaddr, ipaddr);
+	return ethsock_arp(sock, hwaddr, ipaddr, 1);
 }
 
 int ethsock_arp_del(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipaddr)
 {
-	return ethsock_arp(sock, hwaddr, ipaddr, 0, 0);
+	return ethsock_arp(sock, hwaddr, ipaddr, 0);
 }
 #endif
 
diff --git a/nmrp.c b/nmrp.c
index 7995d42..fbb4cea 100644
--- a/nmrp.c
+++ b/nmrp.c
@@ -377,12 +377,19 @@ static int is_valid_ip(struct ethsock *sock, struct in_addr *ipaddr,
 }
 
 static struct ethsock *gsock = NULL;
+static int garp = 0;
+static struct in_addr arpip = { 0 };
+static uint8_t arpmac[6] = { 0 };
 
 static void sigh(int sig)
 {
 	printf("\n");
 	if (gsock) {
+		if (garp) {
+			ethsock_arp_del(gsock, arpmac, &arpip);
+		}
 		ethsock_close(gsock);
+		gsock = NULL;
 	}
 
 	exit(1);
@@ -465,6 +472,7 @@ int nmrp_do(struct nmrpd_args *args)
 	}
 
 	gsock = sock;
+	garp = 0;
 	sigh_orig = signal(SIGINT, sigh);
 
 	if (ethsock_set_timeout(sock, args->rx_timeout)) {
@@ -556,6 +564,15 @@ int nmrp_do(struct nmrpd_args *args)
 				printf("Sending configuration: ip %s, mask %s.\n",
 						args->ipaddr, args->ipmask);
 
+				memcpy(arpmac, rx.eh.ether_shost, 6);
+				memcpy(&arpip, &ipconf.addr, sizeof(ipconf.addr));
+
+				if (ethsock_arp_add(sock, arpmac, &arpip) != 0) {
+					goto out;
+				}
+
+				garp = 1;
+
 				break;
 			case NMRP_C_TFTP_UL_REQ:
 				if (!upload_ok) {
@@ -693,6 +710,7 @@ int nmrp_do(struct nmrpd_args *args)
 out:
 	signal(SIGINT, sigh_orig);
 	gsock = NULL;
+	ethsock_arp_del(sock, arpmac, &arpip);
 	ethsock_close(sock);
 	return status;
 }
diff --git a/nmrpd.h b/nmrpd.h
index 841b4f3..ef25a69 100644
--- a/nmrpd.h
+++ b/nmrpd.h
@@ -100,6 +100,8 @@ int ethsock_send(struct ethsock *sock, void *buf, size_t len);
 ssize_t ethsock_recv(struct ethsock *sock, void *buf, size_t len);
 int ethsock_set_timeout(struct ethsock *sock, unsigned msec);
 uint8_t *ethsock_get_hwaddr(struct ethsock *sock);
+int ethsock_arp_add(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipaddr);
+int ethsock_arp_del(struct ethsock *sock, uint8_t *hwaddr, struct in_addr *ipaddr);
 int ethsock_list_all(void);
 
 struct ethsock_ip_callback_args
-- 
2.25.1