From 08cda4004491d3971a8b9df937426c43800d15b1 Mon Sep 17 00:00:00 2001
From: Jian Liang <jianliang@tycoint.com>
Date: Thu, 5 Oct 2017 09:37:06 +0100
Subject: [PATCH 2/4] inet: Implement subnet route creation/deletion in
 iproute_default_modify
To: connman@lists.01.org
Cc: wagi@monom.org

- Calculate subnet address base on gateway address and prefixlen
- Differentiate creation of routes to gateway and subnet

Signed-off-by: Jian Liang <jianliang@tycoint.com>

---
Upstream-Status: Backport [https://git.kernel.org/pub/scm/network/connman/connman.git/commit/?id=ff7dcf91f12a2a237feebc6e606d0a8e92975528]
Signed-off-by: André Draszik <andre.draszik@jci.com>
 src/inet.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/inet.c b/src/inet.c
index ab8aec8..0ddb030 100644
--- a/src/inet.c
+++ b/src/inet.c
@@ -2802,6 +2802,9 @@ static int iproute_default_modify(int cmd, uint32_t table_id, int ifindex,
 	unsigned char buf[sizeof(struct in6_addr)];
 	int ret, len;
 	int family = connman_inet_check_ipaddress(gateway);
+	char *dst = NULL;
+
+	DBG("gateway %s/%u table %u", gateway, prefixlen, table_id);
 
 	switch (family) {
 	case AF_INET:
@@ -2814,7 +2817,19 @@ static int iproute_default_modify(int cmd, uint32_t table_id, int ifindex,
 		return -EINVAL;
 	}
 
-	ret = inet_pton(family, gateway, buf);
+	if (prefixlen) {
+		struct in_addr ipv4_subnet_addr, ipv4_mask;
+
+		memset(&ipv4_subnet_addr, 0, sizeof(ipv4_subnet_addr));
+		ipv4_mask.s_addr = htonl((0xffffffff << (32 - prefixlen)) & 0xffffffff);
+		ipv4_subnet_addr.s_addr = inet_addr(gateway);
+		ipv4_subnet_addr.s_addr &= ipv4_mask.s_addr;
+
+		dst = g_strdup(inet_ntoa(ipv4_subnet_addr));
+	}
+
+	ret = inet_pton(family, dst ? dst : gateway, buf);
+	g_free(dst);
 	if (ret <= 0)
 		return -EINVAL;
 
@@ -2831,8 +2846,9 @@ static int iproute_default_modify(int cmd, uint32_t table_id, int ifindex,
 	rth.req.u.r.rt.rtm_type = RTN_UNICAST;
 	rth.req.u.r.rt.rtm_dst_len = prefixlen;
 
-	__connman_inet_rtnl_addattr_l(&rth.req.n, sizeof(rth.req), RTA_GATEWAY,
-								buf, len);
+	__connman_inet_rtnl_addattr_l(&rth.req.n, sizeof(rth.req),
+		prefixlen > 0 ? RTA_DST : RTA_GATEWAY, buf, len);
+
 	if (table_id < 256) {
 		rth.req.u.r.rt.rtm_table = table_id;
 	} else {
-- 
2.7.4