platform/netlink: add flags argument to nl_socket_new()

The real purpose is that we set the socket options before bind().
For that, we need to be able to specify the flag during nl_socket_new().

Another reason is that these are common questions to ponder while
creating a netlink socket. There shouldn't be several setter functions,
just specify the flag right away. These parameters are not going to
change afterwards (at least, we don't need/use that and we don't have
API for that either).

src/libnm-platform/nm-linux-platform.c

@@ -9747,7 +9747,7 @@ constructed(GObject *_object)
 
     /*************************************************************************/
 
-    nle = nl_socket_new(&priv->sk_genl_sync, NETLINK_GENERIC, TRUE, 0, 0);
+    nle = nl_socket_new(&priv->sk_genl_sync, NETLINK_GENERIC, NL_SOCKET_FLAGS_NONE, 0, 0);
     g_assert(!nle);
 
     _LOGD("genl: generic netlink socket for sync operations created: port=%u, fd=%d",
@@ -9756,18 +9756,15 @@ constructed(GObject *_object)
 
     /*************************************************************************/
 
-    nle = nl_socket_new(&priv->sk_rtnl, NETLINK_ROUTE, FALSE, 8 * 1024 * 1024, 0);
+    /* disable MSG_PEEK, we will handle lost messages ourselves. */
+    nle = nl_socket_new(&priv->sk_rtnl,
+                        NETLINK_ROUTE,
+                        NL_SOCKET_FLAGS_NONBLOCK | NL_SOCKET_FLAGS_PASSCRED
+                            | NL_SOCKET_FLAGS_DISABLE_MSG_PEEK,
+                        8 * 1024 * 1024,
+                        0);
     g_assert(!nle);
 
-    nle = nl_socket_set_passcred(priv->sk_rtnl, 1);
-    g_assert(!nle);
-
-    /* explicitly set the msg buffer size and disable MSG_PEEK.
-     * We use our own receive buffer priv->netlink_recv_buf.
-     * If we encounter NME_NL_MSG_TRUNC, we will increase the buffer
-     * and resync (as we would have lost the message without NL_MSG_PEEK). */
-    nl_socket_disable_msg_peek(priv->sk_rtnl);
-
     nle = nl_socket_add_memberships(priv->sk_rtnl,
                                     RTNLGRP_IPV4_IFADDR,
                                     RTNLGRP_IPV4_ROUTE,

src/libnm-platform/nm-netlink.c

@@ -1061,7 +1061,11 @@ nl_socket_disable_msg_peek(struct nl_sock *sk)
 /*****************************************************************************/
 
 int
-nl_socket_new(struct nl_sock **out_sk, int protocol, bool blocking, int bufsize_rx, int bufsize_tx)
+nl_socket_new(struct nl_sock **out_sk,
+              int              protocol,
+              NLSocketFlags    flags,
+              int              bufsize_rx,
+              int              bufsize_tx)
 {
     nm_auto_nlsock struct nl_sock *sk = NULL;
     nm_auto_close int              fd = -1;
@@ -1073,7 +1077,10 @@ nl_socket_new(struct nl_sock **out_sk, int protocol, bool blocking, int bufsize_
 
     nm_assert(out_sk && !*out_sk);
 
-    fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC | (blocking ? 0 : SOCK_NONBLOCK), protocol);
+    fd = socket(AF_NETLINK,
+                SOCK_RAW | SOCK_CLOEXEC
+                    | (NM_FLAGS_HAS(flags, NL_SOCKET_FLAGS_NONBLOCK) ? SOCK_NONBLOCK : 0),
+                protocol);
     if (fd < 0)
         return -nm_errno_from_native(errno);
 
@@ -1096,12 +1103,27 @@ nl_socket_new(struct nl_sock **out_sk, int protocol, bool blocking, int bufsize_
             },
         .s_seq_expect = t,
         .s_seq_next   = t,
+        .s_flags      = NM_FLAGS_HAS(flags, NL_SOCKET_FLAGS_DISABLE_MSG_PEEK) ? 0 : NL_MSG_PEEK,
     };
 
     nmerr = nl_socket_set_buffer_size(sk, bufsize_rx, bufsize_tx);
     if (nmerr < 0)
         return nmerr;
 
+    (void) nl_socket_set_ext_ack(sk, TRUE);
+
+    if (NM_FLAGS_HAS(flags, NL_SOCKET_FLAGS_PASSCRED)) {
+        err = nl_socket_set_passcred(sk, 1);
+        if (err < 0)
+            return err;
+    }
+
+    if (NM_FLAGS_HAS(flags, NL_SOCKET_FLAGS_PKTINFO)) {
+        err = nl_socket_set_pktinfo(sk, 1);
+        if (err < 0)
+            return err;
+    }
+
     err = bind(sk->s_fd, (struct sockaddr *) &sk->s_local, sizeof(sk->s_local));
     if (err != 0)
         return -nm_errno_from_native(errno);
@@ -1117,8 +1139,6 @@ nl_socket_new(struct nl_sock **out_sk, int protocol, bool blocking, int bufsize_
     if (local.nl_family != AF_NETLINK)
         return -NME_UNSPEC;
 
-    (void) nl_socket_set_ext_ack(sk, TRUE);
-
     sk->s_local = local;
     sk->s_proto = protocol;
 

src/libnm-platform/nm-netlink.h

@@ -507,13 +507,26 @@ nlmsg_put(struct nl_msg *n, uint32_t pid, uint32_t seq, int type, int payload, i
 
 /*****************************************************************************/
 
+typedef enum {
+    NL_SOCKET_FLAGS_NONE             = 0,
+    NL_SOCKET_FLAGS_NONBLOCK         = 0x1,
+    NL_SOCKET_FLAGS_PASSCRED         = 0x2,
+    NL_SOCKET_FLAGS_PKTINFO          = 0x4,
+    NL_SOCKET_FLAGS_DISABLE_MSG_PEEK = 0x8,
+
+    _NL_SOCKET_FLAGS_ALL = (NL_SOCKET_FLAGS_DISABLE_MSG_PEEK << 1) - 1,
+} NLSocketFlags;
+
 #define NL_AUTO_PORT 0
 #define NL_AUTO_SEQ  0
 
 struct nl_sock;
 
-int
+int nl_socket_new(struct nl_sock **out_sk,
-nl_socket_new(struct nl_sock **out_sk, int protocol, bool blocking, int bufsize_rx, int bufsize_tx);
+                  int              protocol,
+                  NLSocketFlags    flags,
+                  int              bufsize_rx,
+                  int              bufsize_tx);
 
 void nl_socket_free(struct nl_sock *sk);