Linux network stats (#44)

* Add libnl-3 and libnl-route-3 dependency if Linux (libnl-3-dev on ubuntu)
* Add libnl-3 flags, refactor stats/dune

Use dune-configurtator to get C flags. In the dune-configurator script,
we detect whether we're running on Linux or FreeBSD.

albatross.opam

@@ -9,6 +9,7 @@ license: "ISC"
 depends: [
   "ocaml" {>= "4.08.0"}
   "dune"
+  "dune-configurator"
   "lwt" {>= "3.0.0"}
   "ipaddr" {>= "4.0.0"}
   "hex"
@@ -37,4 +38,8 @@ build: [
   ["dune" "subst"] {pinned}
   ["dune" "build" "-p" name "-j" jobs]
 ]
+depexts: [
+  ["libnl-3-dev" "libnl-route-3-dev"] {os-family = "debian"}
+  ["libnl3" "libnl3-devel"] {os-family = "centos"}
+]
 synopsis: "Albatross - orchestrate and manage MirageOS unikernels with Solo5"

stats/albatross_stats_stubs.c

@@ -211,7 +211,100 @@ CAMLprim value vmmanage_sysctl_ifdata (value num) {
 
   CAMLreturn(res);
 }
-#else /* FreeBSD */
+#elif __linux__ /* FreeBSD */
+#include <netlink/netlink.h>
+#include <netlink/socket.h>
+#include <netlink/route/link.h>
+
+#define get_stat(link, stat) rtnl_link_get_stat(link, RTNL_LINK_##stat)
+
+CAMLprim value vmmanage_sysctl_ifcount(value unit) {
+  CAMLparam1(unit);
+  int err;
+  struct nl_sock *nl_sock;
+  struct nl_cache *link_cache;
+
+  nl_sock = nl_socket_alloc();
+  if (nl_sock == 0)
+    uerror("nl_socket_alloc", Nothing);
+  err = nl_connect(nl_sock, NETLINK_ROUTE);
+  if (err < 0)
+    uerror("nl_connect", Nothing);
+  err = rtnl_link_alloc_cache(nl_sock, AF_UNSPEC, &link_cache);
+  if (err < 0)
+    uerror("rtnl_link_alloc_cache", Nothing);
+
+  CAMLreturn(Val_long(nl_cache_nitems(link_cache)));
+}
+
+CAMLprim value vmmanage_sysctl_ifdata(value num) {
+  CAMLparam1(num);
+  CAMLlocal1(res);
+  int err;
+  struct nl_sock *nl_sock;
+  struct nl_cache *link_cache;
+  struct rtnl_link *link;
+
+  nl_sock = nl_socket_alloc();
+  if (nl_sock == 0)
+    uerror("nl_socket_alloc", Nothing);
+  err = nl_connect(nl_sock, NETLINK_ROUTE);
+  if (err < 0)
+    uerror("nl_connect", Nothing);
+  err = rtnl_link_alloc_cache(nl_sock, AF_UNSPEC, &link_cache);
+  if (err < 0)
+    uerror("rtnl_link_alloc_cache", Nothing);
+  link = rtnl_link_get(link_cache, Int_val(num));
+  if (link == NULL)
+    uerror("rtnl_link_get", Nothing);
+  res = caml_alloc(18, 0);
+  Store_field(res, 0, caml_copy_string(rtnl_link_get_name(link)));
+  Store_field(res, 1, Val32(rtnl_link_get_flags(link)));
+  Store_field(res, 2, Val32(0)); /* send_length */
+  Store_field(res, 3, Val32(0)); /* max_send_length */
+  Store_field(res, 4, Val32(0)); /* send_drops */
+  Store_field(res, 5, Val32(rtnl_link_get_mtu(link)));
+  Store_field(res, 6, Val64(0)); /* baudrate */
+  Store_field(res, 7, Val64(get_stat(link, RX_PACKETS)));
+  Store_field(res, 8, Val64(get_stat(link, RX_ERRORS)));
+  Store_field(res, 9, Val64(get_stat(link, TX_PACKETS)));
+  Store_field(res, 10, Val64(get_stat(link, TX_ERRORS)));
+  Store_field(res, 11, Val64(get_stat(link, COLLISIONS)));
+  Store_field(res, 12, Val64(get_stat(link, RX_BYTES)));
+  Store_field(res, 13, Val64(get_stat(link, TX_BYTES)));
+  Store_field(res, 14, Val64(get_stat(link, MULTICAST)));
+  Store_field(res, 15, Val64(0));
+  Store_field(res, 16, Val64(get_stat(link, RX_DROPPED)));
+  Store_field(res, 17, Val64(get_stat(link, TX_DROPPED)));
+  CAMLreturn(res);
+}
+
+CAMLprim value vmmanage_sysctl_kinfo_proc (value pid_r) {
+  CAMLparam1(pid_r);
+  uerror("sysctl_kinfo_proc", Nothing);
+}
+
+CAMLprim value vmmanage_vmmapi_open (value name) {
+  CAMLparam1(name);
+  uerror("vmmapi_open", Nothing);
+}
+
+CAMLprim value vmmanage_vmmapi_close (value name) {
+  CAMLparam1(name);
+  uerror("vmmapi_close", Nothing);
+}
+
+CAMLprim value vmmanage_vmmapi_stats (value name) {
+  CAMLparam1(name);
+  uerror("vmmapi_stats", Nothing);
+}
+
+CAMLprim value vmmanage_vmmapi_statnames (value name) {
+  CAMLparam1(name);
+  uerror("vmmapi_statnames", Nothing);
+}
+
+#else /* Linux */
 
 /* stub symbols for OS currently not supported */
 

stats/config/discover.ml

@@ -0,0 +1,39 @@
+module C = Configurator.V1
+
+let write_sexp (conf : C.Pkg_config.package_conf) =
+  C.Flags.write_sexp "c_flags.sexp" conf.cflags;
+  C.Flags.write_sexp "c_library_flags.sexp" conf.libs
+
+let pkg_config_combine ~default deps =
+  let deps =
+    List.map (Result.fold ~ok:(fun x -> x) ~error:(fun e -> C.die "pkg-config: %s" e))
+      deps in
+  List.fold_left (fun conf dep ->
+      C.Pkg_config.{ libs = conf.libs @ dep.libs;
+                     cflags = conf.cflags @ dep.cflags })
+    default deps
+
+let freebsd _c =
+  let conf = { C.Pkg_config.libs = ["-lvmmapi"]; cflags = [] } in
+  write_sexp conf
+
+let linux c =
+  (* FIXME: cflags -I *)
+  let default = { C.Pkg_config.libs = ["-lnl-3"; "-lnl-route-3"]; cflags = [] } in
+  let conf =
+    match C.Pkg_config.get c with
+    | None -> default
+    | Some pc ->
+      pkg_config_combine ~default [
+        C.Pkg_config.query_expr_err pc ~package:"libnl-3.0" ~expr:"libnl-3.0";
+        C.Pkg_config.query_expr_err pc ~package:"libnl-route-3.0" ~expr:"libnl-route-3.0";
+      ]
+  in
+  write_sexp conf
+
+let () =
+  C.main ~name:"libnl-3-pkg-config" (fun c ->
+      match C.ocaml_config_var_exn c "system" with
+      | "freebsd" -> freebsd c
+      | "linux" -> linux c
+      | os -> failwith ("Unsupported platform: "^os))

stats/config/dune

@@ -0,0 +1,3 @@
+(executable
+ (name discover)
+ (libraries dune.configurator))

stats/dune

@@ -1,15 +1,11 @@
-(* -*- tuareg -*- *)
-
-let freebsd = try Sys.command "uname -s | grep -c FreeBSD > /dev/null" = 0 with _ -> false
-
-let () =
-  Jbuild_plugin.V1.send @@ Printf.sprintf {|
 (library
   (name albatross_stats)
   (public_name albatross.stats)
   (libraries albatross)
   (wrapped false)
   (c_names albatross_stats_stubs)
+  (c_flags (:include c_flags.sexp))
+  (c_library_flags (:include c_library_flags.sexp))
   (modules albatross_stats_pure))
 
 (executable
@@ -17,7 +13,6 @@ let () =
   (public_name albatross-stats)
   (package albatross)
   (modules albatross_stats)
-  %s
   (libraries albatross.cli albatross.stats albatross))
 
 (executable
@@ -25,9 +20,8 @@ let () =
   (public_name albatross-stat-client)
   (package albatross)
   (modules albatross_stat_client)
-  %s
   (libraries albatross.cli albatross.stats albatross))
- |}
-  (if freebsd then "(link_flags (-ccopt \"-lvmmapi\"))" else "")
-  (if freebsd then "(link_flags (-ccopt \"-lvmmapi\"))" else "")
 
+(rule
+  (targets c_flags.sexp c_library_flags.sexp)
+  (action (run ./config/discover.exe)))