[Dnsmasq-discuss] [PATCH] fix entries in /etc/hosts disabling static leases

[Steven Siloti]

It is possible for a config entry to have one address family specified by a
dhcp-host directive and the other added from /etc/hosts. This is especially
common on OpenWrt because it uses odhcpd for DHCPv6 and IPv6 leases are
imported into dnsmasq via a hosts file.

To handle this case there need to be separate *_HOSTS flags for IPv4 and IPv6.
Otherwise when the hosts file is reloaded it will clear the CONFIG_ADDR(6) flag
which was set by the dhcp-host directive.
---
 src/dhcp-common.c | 8 ++++++--
 src/dnsmasq.h     | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/dhcp-common.c b/src/dhcp-common.c
index d1254d9..7eb3761 100644
--- a/src/dhcp-common.c
+++ b/src/dhcp-common.c
@@ -372,7 +372,11 @@ void dhcp_update_configs(struct dhcp_config *configs)
 
   for (config = configs; config; config = config->next)
     if (config->flags & CONFIG_ADDR_HOSTS)
-      config->flags &= ~(CONFIG_ADDR | CONFIG_ADDR6 | CONFIG_ADDR_HOSTS);
+      config->flags &= ~(CONFIG_ADDR | CONFIG_ADDR_HOSTS);
+#ifdef HAVE_DHCP6
+    if (config->flags & CONFIG_ADDR6_HOSTS)
+      config->flags &= ~(CONFIG_ADDR6 | CONFIG_ADDR6_HOSTS);
+#endif
 
 #ifdef HAVE_DHCP6 
  again:  
@@ -421,7 +425,7 @@ void dhcp_update_configs(struct dhcp_config *configs)
 		(!(conf_tmp = config_find_by_address6(configs, &crec->addr.addr6, 128, 0)) || conf_tmp == config))
 	      {
 		memcpy(&config->addr6, &crec->addr.addr6, IN6ADDRSZ);
-		config->flags |= CONFIG_ADDR6 | CONFIG_ADDR_HOSTS;
+		config->flags |= CONFIG_ADDR6 | CONFIG_ADDR6_HOSTS;
 		continue;
 	      }
 #endif
diff --git a/src/dnsmasq.h b/src/dnsmasq.h
index 95559c7..0dc1de9 100644
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -789,6 +789,7 @@ struct dhcp_config {
 #define CONFIG_BANK           2048    /* from dhcp hosts file */
 #define CONFIG_ADDR6          4096
 #define CONFIG_WILDCARD       8192
+#define CONFIG_ADDR6_HOSTS   16384    /* address added by from /etc/hosts */
 
 struct dhcp_opt {
   int opt, len, flags;
-- 
2.20.1