From: Martin Schwenke <mschwenke@ddn.com>
Date: Mon, 8 Dec 2025 08:24:33 +0000 (+1100)
Subject: ctdb-common: Pass hardware address to arp_build()
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=dce91dd4d28fef6c6f5eb7ed8a598dddfeaa15d8;p=thirdparty%2Fsamba.git

ctdb-common: Pass hardware address to arp_build()

Use the address, length and hardware type.  arp_build() now works for
any supported hardware address length.

Update the test code to construct the required sockaddr_ll structure.

Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
Reviewed-by: Vinit Agnihotri <vagnihot@redhat.com>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>
---

diff --git a/ctdb/common/system_socket.c b/ctdb/common/system_socket.c
index 7fac07452a9..051455ddb2b 100644
--- a/ctdb/common/system_socket.c
+++ b/ctdb/common/system_socket.c
@@ -460,7 +460,7 @@ done:
 static int arp_build(uint8_t *buffer,
 		     size_t buflen,
 		     const struct sockaddr_in *addr,
-		     const struct ether_addr *hwaddr,
+		     const struct sockaddr_ll *hardware_addr,
 		     uint16_t arpop,
 		     size_t *len)
 {
@@ -488,9 +488,9 @@ static int arp_build(uint8_t *buffer,
 	 * standard.
 	 */
 	l = sizeof(struct arphdr) +
-		ETH_ALEN +
+		hardware_addr->sll_halen +
 		sizeof(addr->sin_addr) +
-		ETH_ALEN +
+		hardware_addr->sll_halen +
 		sizeof(addr->sin_addr);
 	if (buflen < l) {
 		return EMSGSIZE;
@@ -500,23 +500,23 @@ static int arp_build(uint8_t *buffer,
 
 	p = buffer;
 	ah = (struct arphdr *)p;
-	ah->ar_hrd = htons(ARPHRD_ETHER);
+	ah->ar_hrd = htons(hardware_addr->sll_hatype);
 	ah->ar_pro = htons(ETH_P_IP);
-	ah->ar_hln = ETH_ALEN;
+	ah->ar_hln = hardware_addr->sll_halen;
 	ah->ar_pln = sizeof(addr->sin_addr);
 	ah->ar_op = htons(arpop);
 	p += sizeof(struct arphdr);
 
-	memcpy(p, hwaddr, ETH_ALEN);
-	p += ETH_ALEN;
+	memcpy(p, &hardware_addr->sll_addr, hardware_addr->sll_halen);
+	p += hardware_addr->sll_halen;
 	memcpy(p, &addr->sin_addr, sizeof(addr->sin_addr));
 	p += sizeof(addr->sin_addr);
 	if (arpop == ARPOP_REQUEST) {
 		/* Field must be all 0s - already done by memset() above */
 	} else {
-		memcpy(p, hwaddr, ETH_ALEN);
+		memcpy(p, hardware_addr->sll_addr, hardware_addr->sll_halen);
 	}
-	p += ETH_ALEN;
+	p += hardware_addr->sll_halen;
 	memcpy(p, &addr->sin_addr, sizeof(addr->sin_addr));
 
 	*len = l;
@@ -794,6 +794,7 @@ int ctdb_sys_send_arp(const ctdb_sock_addr *addr, const char *iface)
 	switch (addr->ip.sin_family) {
 	case AF_INET:
 		/* Send gratuitous ARP */
+		hardware_addr_ll->sll_protocol = htons(ETH_P_ARP);
 		broadcast_addr_ll->sll_protocol = htons(ETH_P_ARP);
 		/*
 		 * Unlikely to be different to previous dest_len
@@ -804,7 +805,7 @@ int ctdb_sys_send_arp(const ctdb_sock_addr *addr, const char *iface)
 		ret = arp_build(buffer,
 				sizeof(buffer),
 				&addr->ip,
-				hwaddr,
+				hardware_addr_ll,
 				ARPOP_REQUEST,
 				&len);
 		if (ret != 0) {
@@ -828,7 +829,7 @@ int ctdb_sys_send_arp(const ctdb_sock_addr *addr, const char *iface)
 		ret = arp_build(buffer,
 				sizeof(buffer),
 				&addr->ip,
-				hwaddr,
+				hardware_addr_ll,
 				ARPOP_REPLY,
 				&len);
 		if (ret != 0) {
diff --git a/ctdb/tests/src/system_socket_test.c b/ctdb/tests/src/system_socket_test.c
index edaf1c78a38..58c01ddd148 100644
--- a/ctdb/tests/src/system_socket_test.c
+++ b/ctdb/tests/src/system_socket_test.c
@@ -71,12 +71,34 @@ static void test_types(void)
 
 #ifdef CTDB_CAN_SEND_ARPS
 
+static void hwaddr_to_sockaddr_ll(const char *asc, struct sockaddr_ll *sall)
+{
+	struct ether_addr *hw = NULL;
+
+	*sall = (struct sockaddr_ll) {
+		.sll_family = AF_PACKET,
+		.sll_protocol = htons(ETH_P_ALL),
+		.sll_ifindex = 2,
+		.sll_pkttype = PACKET_HOST,
+		.sll_hatype = ARPHRD_ETHER,
+		.sll_halen = ETH_ALEN,
+	};
+
+	hw = ether_aton(asc);
+	assert(hw != NULL);
+
+	memcpy(&sall->sll_addr[0], hw, ETH_ALEN);
+}
+
 static void test_arp(const char *addr_str,
 		     const char *hwaddr_str,
 		     uint16_t arpop)
 {
 	ctdb_sock_addr addr;
-	struct ether_addr *hw = NULL;
+	struct sockaddr_storage hardware_addr = {};
+	struct sockaddr_ll *sall = (struct sockaddr_ll *)&hardware_addr;
+	/* Temporarily used for IPv6 - it still takes an ethernet address */
+	struct ether_addr *hw = (struct ether_addr *)&sall->sll_addr[0];
 	uint8_t buf[512];
 	size_t buflen = sizeof(buf);
 	size_t len;
@@ -85,12 +107,11 @@ static void test_arp(const char *addr_str,
 	ret = ctdb_sock_addr_from_string(addr_str, &addr, false);
 	assert(ret == 0);
 
-	hw = ether_aton(hwaddr_str);
-	assert(hw != NULL);
+	hwaddr_to_sockaddr_ll(hwaddr_str, sall);
 
 	switch (addr.ip.sin_family) {
 	case AF_INET:
-		ret = arp_build(buf, buflen, &addr.ip, hw, arpop, &len);
+		ret = arp_build(buf, buflen, &addr.ip, sall, arpop, &len);
 		break;
 	case AF_INET6:
 		ret = ip6_na_build(buf, buflen, &addr.ip6, hw, &len);