1 files changed, 90 insertions, 0 deletions
diff --git a/utilities/nlmon.c b/utilities/nlmon.c
new file mode 100644
index 000000000..eb1be60a7
--- /dev/null
+++ b/utilities/nlmon.c
@@ -0,0 +1,90 @@
+#include <config.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <net/if.h>
+#include <poll.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <stddef.h>
+#include <linux/rtnetlink.h>
+#include "netlink.h"
+#include "ofpbuf.h"
+#include "poll-loop.h"
+#include "timeval.h"
+#include "util.h"
+#include "vlog.h"
+
+static const struct nl_policy rtnlgrp_link_policy[] = {
+    [IFLA_IFNAME] = { .type = NL_A_STRING, .optional = false },
+    [IFLA_MASTER] = { .type = NL_A_U32, .optional = true },
+};
+
+int
+main(int argc UNUSED, char *argv[])
+{
+    struct nl_sock *sock;
+    int error;
+
+    set_program_name(argv[0]);
+    time_init();
+    vlog_init();
+    vlog_set_levels(VLM_ANY_MODULE, VLF_ANY_FACILITY, VLL_DBG);
+
+    error = nl_sock_create(NETLINK_ROUTE, RTNLGRP_LINK, 0, 0, &sock);
+    if (error) {
+        ovs_fatal(error, "could not create rtnetlink socket");
+    }
+
+    for (;;) {
+        struct ofpbuf *buf;
+
+        error = nl_sock_recv(sock, &buf, false);
+        if (error == EAGAIN) {
+            /* Nothing to do. */
+        } else if (error == ENOBUFS) {
+            ovs_error(0, "network monitor socket overflowed");
+        } else if (error) {
+            ovs_fatal(error, "error on network monitor socket");
+        } else {
+            struct nlattr *attrs[ARRAY_SIZE(rtnlgrp_link_policy)];
+            struct nlmsghdr *nlh;
+            struct ifinfomsg *iim;
+
+            nlh = ofpbuf_at(buf, 0, NLMSG_HDRLEN);
+            iim = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *iim);
+            if (!iim) {
+                ovs_error(0, "received bad rtnl message (no ifinfomsg)");
+                ofpbuf_delete(buf);
+                continue;
+            }
+
+            if (!nl_policy_parse(buf, NLMSG_HDRLEN + sizeof(struct ifinfomsg),
+                                 rtnlgrp_link_policy,
+                                 attrs, ARRAY_SIZE(rtnlgrp_link_policy))) {
+                ovs_error(0, "received bad rtnl message (policy)");
+                ofpbuf_delete(buf);
+                continue;
+            }
+            printf("netdev %s changed (%s):\n",
+                   nl_attr_get_string(attrs[IFLA_IFNAME]),
+                   (nlh->nlmsg_type == RTM_NEWLINK ? "RTM_NEWLINK"
+                    : nlh->nlmsg_type == RTM_DELLINK ? "RTM_DELLINK"
+                    : nlh->nlmsg_type == RTM_GETLINK ? "RTM_GETLINK"
+                    : nlh->nlmsg_type == RTM_SETLINK ? "RTM_SETLINK"
+                    : "other"));
+            if (attrs[IFLA_MASTER]) {
+                uint32_t idx = nl_attr_get_u32(attrs[IFLA_MASTER]);
+                char ifname[IFNAMSIZ];
+                if (!if_indextoname(idx, ifname)) {
+                    strcpy(ifname, "unknown");
+                }
+                printf("\tmaster=%"PRIu32" (%s)\n", idx, ifname);
+            }
+            ofpbuf_delete(buf);
+        }
+
+        nl_sock_wait(sock, POLLIN);
+        poll_block();
+    }
+}
+