From fca3fee38ea48843f277e26624e9555d8b74edc5 Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20H=C3=A4rdeman?= <david@hardeman.nu>
Date: Tue, 18 Nov 2025 08:55:41 +0100
Subject: [PATCH] netlink: add netmask for IPv4
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Add a netmask member to struct odhcpd_ipaddr, this is mostly for
convenience.

Signed-off-by: David Härdeman <david@hardeman.nu>
Link: https://github.com/openwrt/odhcpd/pull/320
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 src/netlink.c | 3 +++
 src/odhcpd.h  | 1 +
 2 files changed, 4 insertions(+)

diff --git a/src/netlink.c b/src/netlink.c
index d09e3f8..c07a9e4 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -571,6 +571,9 @@ static int cb_addr_valid(struct nl_msg *msg, void *arg)
 	memset(&oaddrs[ctxt->ret], 0, sizeof(oaddrs[ctxt->ret]));
 	oaddrs[ctxt->ret].prefix_len = ifa->ifa_prefixlen;
 
+	if (ifa->ifa_family == AF_INET)
+		oaddrs[ctxt->ret].netmask = htonl(~((1U << (32 - ifa->ifa_prefixlen)) - 1));
+
 	nla_memcpy(&oaddrs[ctxt->ret].addr, nla_addr, sizeof(oaddrs[ctxt->ret].addr));
 
 	if (nla[IFA_BROADCAST])
diff --git a/src/odhcpd.h b/src/odhcpd.h
index e708f34..88135f1 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -176,6 +176,7 @@ struct odhcpd_ipaddr {
 		/* IPv4 only */
 		struct {
 			struct in_addr broadcast;
+			in_addr_t netmask;
 		};
 	};
 };
-- 
2.30.2