dhcp-network: enable IP_FREEBIND for UDP sockets

This allows the sockets to be bound to a specific address before it is configured,
also enable SO_REUSEADDR to allow multiple DHCP clients to run at the same time.

diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c
index 16411cc41a384aa082d29047d7a9f517cb1bf42b..29276c0559b07a90213a95da9cb5395ff26d5b41 100644 (file)
--- a/src/libsystemd-network/dhcp-network.c
+++ b/src/libsystemd-network/dhcp-network.c
@@ -126,7 +126,7 @@ int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) {
                 .in.sin_addr.s_addr = address,
         };
         _cleanup_close_ int s = -1;
-        int r, tos = IPTOS_CLASS_CS6;
+        int r, on = 1, tos = IPTOS_CLASS_CS6;
 
         s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0);
         if (s < 0)
@@ -136,13 +136,11 @@ int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) {
         if (r < 0)
                 return -errno;
 
-        if (address == INADDR_ANY) {
-                int on = 1;
-
-                r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
-                if (r < 0)
-                        return -errno;
+        r = setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+        if (r < 0)
+                return -errno;
 
+        if (address == INADDR_ANY) {
                 r = setsockopt(s, IPPROTO_IP, IP_PKTINFO, &on, sizeof(on));
                 if (r < 0)
                         return -errno;
@@ -150,6 +148,10 @@ int dhcp_network_bind_udp_socket(be32_t address, uint16_t port) {
                 r = setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on));
                 if (r < 0)
                         return -errno;
+        } else {
+                r = setsockopt(s, IPPROTO_IP, IP_FREEBIND, &on, sizeof(on));
+                if (r < 0)
+                        return -errno;
         }
 
         r = bind(s, &src.sa, sizeof(src.in));