From: David Härdeman <david@hardeman.nu>
Date: Mon, 6 Oct 2025 14:45:38 +0000 (+0200)
Subject: dhcpv4: some minor cleanups post-iovec
X-Git-Url: http://git.openwrt.org/%22https:/collectd.org//%22/%22https:/collectd.org/%22?a=commitdiff_plain;h=be68f423c528233111dfec13456c46077ee489fb;p=project%2Fodhcpd.git

dhcpv4: some minor cleanups post-iovec

Do some cleanups, remove some magic numbers, make sure structs are defined with
the members in their actual order and without missing members.

Signed-off-by: David Härdeman <david@hardeman.nu>
Link: https://github.com/openwrt/odhcpd/pull/278
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 70b36be..8d127e0 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -161,6 +161,7 @@ static void dhcpv4_fr_send(struct dhcp_assignment *a)
 		.htype = ARPHRD_ETHER,
 		.hlen = ETH_ALEN,
 		.hops = 0,
+		.xid = 0,
 		.secs = 0,
 		.flags = 0,
 		.ciaddr = { INADDR_ANY },
@@ -664,15 +665,19 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 	/* Reply variables */
 	struct dhcpv4_message reply = {
 		.op = DHCPV4_OP_BOOTREPLY,
-		.htype = req->htype,
-		.hlen = req->hlen,
+		.htype = ARPHRD_ETHER,
+		.hlen = ETH_ALEN,
 		.hops = 0,
 		.xid = req->xid,
 		.secs = 0,
 		.flags = req->flags,
 		.ciaddr = { INADDR_ANY },
-		.giaddr = req->giaddr,
+		.yiaddr = { INADDR_ANY },
 		.siaddr = iface->dhcpv4_local,
+		.giaddr = req->giaddr,
+		.chaddr = { 0 },
+		.sname = { 0 },
+		.file = { 0 },
 		.cookie = htonl(DHCPV4_MAGIC_COOKIE),
 	};
 	struct dhcpv4_option_u8 reply_msg = {
@@ -788,7 +793,9 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 	/* FIXME: would checking the magic cookie value here break any clients? */
 
 	if (len < offsetof(struct dhcpv4_message, options) ||
-	    req->op != DHCPV4_OP_BOOTREQUEST || req->hlen != ETH_ALEN)
+	    req->op != DHCPV4_OP_BOOTREQUEST ||
+	    req->htype != ARPHRD_ETHER ||
+	    req->hlen != ETH_ALEN)
 		return;
 
 	debug("Got DHCPv4 request on %s", iface->name);
@@ -798,8 +805,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 		return;
 	}
 
-	memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
-
 	struct dhcpv4_option *opt;
 	dhcpv4_for_each_option(req->options, (uint8_t *)data + len, opt) {
 		switch (opt->code) {
@@ -855,6 +860,8 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 	}
 
 	switch (req_msg) {
+	case DHCPV4_MSG_INFORM:
+		break;
 	case DHCPV4_MSG_DISCOVER:
 		_fallthrough;
 	case DHCPV4_MSG_REQUEST:
@@ -866,8 +873,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 				 &req_leasetime, req_hostname, req_hostname_len,
 				 req_accept_fr, &incl_fr_opt, &fr_serverid);
 		break;
-	case DHCPV4_MSG_INFORM:
-		break;
 	default:
 		return;
 	}
@@ -909,8 +914,8 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 				reply_serverid.data = fr_serverid;
 
 			if (req->ciaddr.s_addr &&
-					((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
-					 (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
+			    ((iface->dhcpv4_start_ip.s_addr & iface->dhcpv4_mask.s_addr) !=
+			     (req->ciaddr.s_addr & iface->dhcpv4_mask.s_addr)))
 				req->ciaddr.s_addr = INADDR_ANY;
 		}
 		break;
@@ -934,10 +939,6 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 	reply_opts[reply_opts_len++] = DHCPV4_OPT_AUTHENTICATION;
 	reply_opts[reply_opts_len++] = DHCPV4_OPT_SEARCH_DOMAIN;
 	reply_opts[reply_opts_len++] = DHCPV4_OPT_FORCERENEW_NONCE_CAPABLE;
-
-	if (a)
-		reply.yiaddr.s_addr = a->addr;
-
 	memcpy(&reply_opts[reply_opts_len], req_opts, req_opts_len);
 	reply_opts_len += req_opts_len;
 
@@ -1148,6 +1149,11 @@ void dhcpv4_handle_msg(void *src_addr, void *data, size_t len,
 		}
 	}
 
+	if (a)
+		reply.yiaddr.s_addr = a->addr;
+
+	memcpy(reply.chaddr, req->chaddr, sizeof(reply.chaddr));
+
 	dhcpv4_set_dest_addr(iface, reply_msg.data, req, &reply, src_addr, &dest_addr);
 
 	/* FIXME: check for DHCPV4_MIN_PACKET_SIZE */