X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fdpif-linux.c;h=8e584ea5de051a012a823994495ba7ff1a67c3a8;hb=ea7bd5973fb426f3a6ea66b0953c6000980e77ec;hp=5c2c755031d665246c84333cbc2ca36871dda94c;hpb=856081f683d3e7d5b5fa07af4233d285eb205c47;p=openvswitch

diff --git a/lib/dpif-linux.c b/lib/dpif-linux.c
index 5c2c7550..8e584ea5 100644
--- a/lib/dpif-linux.c
+++ b/lib/dpif-linux.c
@@ -15,7 +15,8 @@
  */
 
 #include <config.h>
-#include "dpif.h"
+
+#include "dpif-linux.h"
 
 #include <assert.h>
 #include <ctype.h>
@@ -69,11 +70,11 @@ struct dpif_linux {
 static struct vlog_rate_limit error_rl = VLOG_RATE_LIMIT_INIT(9999, 5);
 
 static int do_ioctl(const struct dpif *, int cmd, const void *arg);
-static int lookup_minor(const char *name, int *minor);
-static int finish_open(struct dpif *, const char *local_ifname);
+static int open_dpif(const struct dpif_linux_vport *local_vport,
+                     struct dpif **);
 static int get_openvswitch_major(void);
-static int create_minor(const char *name, int minor, struct dpif **dpifp);
-static int open_minor(int minor, struct dpif **dpifp);
+static int create_minor(const char *name, int minor);
+static int open_minor(int minor, int *fdp);
 static int make_openvswitch_device(int minor, char **fnp);
 static void dpif_linux_port_changed(const struct rtnetlink_link_change *,
                                     void *dpif);
@@ -120,60 +121,103 @@ static int
 dpif_linux_open(const struct dpif_class *class OVS_UNUSED, const char *name,
                 bool create, struct dpif **dpifp)
 {
+    struct dpif_linux_vport request, reply;
+    struct ofpbuf *buf;
     int minor;
+    int error;
 
     minor = !strncmp(name, "dp", 2)
             && isdigit((unsigned char)name[2]) ? atoi(name + 2) : -1;
     if (create) {
         if (minor >= 0) {
-            return create_minor(name, minor, dpifp);
+            error = create_minor(name, minor);
+            if (error) {
+                return error;
+            }
         } else {
             /* Scan for unused minor number. */
-            for (minor = 0; minor < ODP_MAX; minor++) {
-                int error = create_minor(name, minor, dpifp);
-                if (error != EBUSY) {
+            for (minor = 0; ; minor++) {
+                if (minor >= ODP_MAX) {
+                    /* All datapath numbers in use. */
+                    return ENOBUFS;
+                }
+
+                error = create_minor(name, minor);
+                if (!error) {
+                    break;
+                } else if (error != EBUSY) {
                     return error;
                 }
             }
-
-            /* All datapath numbers in use. */
-            return ENOBUFS;
         }
+    }
+
+    dpif_linux_vport_init(&request);
+    request.cmd = ODP_VPORT_GET;
+    request.port_no = ODPP_LOCAL;
+    if (minor >= 0) {
+        request.dp_idx = minor;
     } else {
-        struct dpif_linux *dpif;
-        struct odp_port port;
-        int error;
+        request.name = name;
+    }
 
-        if (minor < 0) {
-            error = lookup_minor(name, &minor);
-            if (error) {
-                return error;
-            }
-        }
+    error = dpif_linux_vport_transact(&request, &reply, &buf);
+    if (error) {
+        return error;
+    } else if (reply.port_no != ODPP_LOCAL) {
+        /* This is an Open vSwitch device but not the local port.  We
+         * intentionally support only using the name of the local port as the
+         * name of a datapath; otherwise, it would be too difficult to
+         * enumerate all the names of a datapath. */
+        error = EOPNOTSUPP;
+    } else {
+        error = open_dpif(&reply, dpifp);
+    }
 
-        error = open_minor(minor, dpifp);
-        if (error) {
-            return error;
-        }
-        dpif = dpif_linux_cast(*dpifp);
-
-        /* We need the local port's ifindex for the poll function.  Start by
-         * getting the local port's name. */
-        memset(&port, 0, sizeof port);
-        port.port = ODPP_LOCAL;
-        if (ioctl(dpif->fd, ODP_VPORT_QUERY, &port)) {
-            error = errno;
-            if (error != ENODEV) {
-                VLOG_WARN("%s: probe returned unexpected error: %s",
-                          dpif_name(*dpifp), strerror(error));
-            }
-            dpif_uninit(*dpifp, true);
-            return error;
-        }
+    ofpbuf_delete(buf);
+    return error;
+}
+
+static int
+open_dpif(const struct dpif_linux_vport *local_vport, struct dpif **dpifp)
+{
+    int dp_idx = local_vport->dp_idx;
+    struct dpif_linux *dpif;
+    char *name;
+    int error;
+    int fd;
 
-        /* Then use that to finish up opening. */
-        return finish_open(&dpif->dpif, port.devname);
+    error = open_minor(dp_idx, &fd);
+    if (error) {
+        goto error;
     }
+
+    dpif = xmalloc(sizeof *dpif);
+    error = rtnetlink_link_notifier_register(&dpif->port_notifier,
+                                             dpif_linux_port_changed, dpif);
+    if (error) {
+        goto error_free;
+    }
+
+    name = xasprintf("dp%d", dp_idx);
+    dpif_init(&dpif->dpif, &dpif_linux_class, name, dp_idx, dp_idx);
+    free(name);
+
+    dpif->fd = fd;
+    dpif->local_ifname = xstrdup(local_vport->name);
+    dpif->local_ifindex = local_vport->ifindex;
+    dpif->minor = dp_idx;
+    shash_init(&dpif->changed_ports);
+    dpif->change_error = false;
+    *dpifp = &dpif->dpif;
+
+    return 0;
+
+error_free:
+    free(dpif);
+    close(fd);
+error:
+    return error;
 }
 
 static void
@@ -230,91 +274,95 @@ dpif_linux_set_drop_frags(struct dpif *dpif_, bool drop_frags)
     return do_ioctl(dpif_, ODP_SET_DROP_FRAGS, &drop_frags_int);
 }
 
-static void
-translate_vport_type_to_netdev_type(struct odp_port *port)
-{
-    char *type = port->type;
-
-    if (!strcmp(type, "netdev")) {
-        ovs_strlcpy(type, "system", sizeof port->type);
-    } else if (!strcmp(type, "gre")) {
-        const struct tnl_port_config *config;
-
-        config = (struct tnl_port_config *)port->config;
-        if (config->flags & TNL_F_IPSEC) {
-            ovs_strlcpy(type, "ipsec_gre", sizeof port->type);
-        }
-    }
-}
-
-static void
-translate_netdev_type_to_vport_type(struct odp_port *port)
-{
-    char *type = port->type;
-
-    if (!strcmp(type, "system")) {
-        ovs_strlcpy(type, "netdev", sizeof port->type);
-    } else if (!strcmp(type, "ipsec_gre")) {
-        ovs_strlcpy(type, "gre", sizeof port->type);
-    }
-}
-
 static int
-dpif_linux_port_add(struct dpif *dpif, struct netdev *netdev,
+dpif_linux_port_add(struct dpif *dpif_, struct netdev *netdev,
                     uint16_t *port_nop)
 {
+    struct dpif_linux *dpif = dpif_linux_cast(dpif_);
     const char *name = netdev_get_name(netdev);
     const char *type = netdev_get_type(netdev);
-    struct odp_port port;
+    struct dpif_linux_vport request, reply;
+    const struct ofpbuf *options;
+    struct ofpbuf *buf;
     int error;
 
-    memset(&port, 0, sizeof port);
-    strncpy(port.devname, name, sizeof port.devname);
-    strncpy(port.type, type, sizeof port.type);
-    netdev_vport_get_config(netdev, port.config);
-    translate_netdev_type_to_vport_type(&port);
+    dpif_linux_vport_init(&request);
+    request.cmd = ODP_VPORT_NEW;
+    request.dp_idx = dpif->minor;
+    request.type = netdev_vport_get_vport_type(netdev);
+    if (request.type == ODP_VPORT_TYPE_UNSPEC) {
+        VLOG_WARN_RL(&error_rl, "%s: cannot create port `%s' because it has "
+                     "unsupported type `%s'",
+                     dpif_name(dpif_), name, type);
+        return EINVAL;
+    }
+    request.name = name;
+
+    options = netdev_vport_get_options(netdev);
+    if (options && options->size) {
+        request.options = options->data;
+        request.options_len = options->size;
+    }
 
-    error = do_ioctl(dpif, ODP_VPORT_ATTACH, &port);
+    error = dpif_linux_vport_transact(&request, &reply, &buf);
     if (!error) {
-        *port_nop = port.port;
+        *port_nop = reply.port_no;
+        ofpbuf_delete(buf);
     }
 
     return error;
 }
 
 static int
-dpif_linux_port_del(struct dpif *dpif_, uint16_t port_no_)
+dpif_linux_port_del(struct dpif *dpif_, uint16_t port_no)
 {
-    int port_no = port_no_;     /* Kernel expects an "int". */
-    return do_ioctl(dpif_, ODP_VPORT_DETACH, &port_no);
+    struct dpif_linux *dpif = dpif_linux_cast(dpif_);
+    struct dpif_linux_vport vport;
+
+    dpif_linux_vport_init(&vport);
+    vport.cmd = ODP_VPORT_DEL;
+    vport.dp_idx = dpif->minor;
+    vport.port_no = port_no;
+    return dpif_linux_vport_transact(&vport, NULL, NULL);
 }
 
 static int
-dpif_linux_port_query__(const struct dpif *dpif, struct odp_port *port)
+dpif_linux_port_query__(const struct dpif *dpif, uint32_t port_no,
+                        const char *port_name, struct dpif_port *dpif_port)
 {
-    int error = do_ioctl(dpif, ODP_VPORT_QUERY, port);
+    struct dpif_linux_vport request;
+    struct dpif_linux_vport reply;
+    struct ofpbuf *buf;
+    int error;
+
+    dpif_linux_vport_init(&request);
+    request.cmd = ODP_VPORT_GET;
+    request.dp_idx = dpif_linux_cast(dpif)->minor;
+    request.port_no = port_no;
+    request.name = port_name;
+
+    error = dpif_linux_vport_transact(&request, &reply, &buf);
     if (!error) {
-        translate_vport_type_to_netdev_type(port);
+        dpif_port->name = xstrdup(reply.name);
+        dpif_port->type = xstrdup(netdev_vport_get_netdev_type(&reply));
+        dpif_port->port_no = reply.port_no;
+        ofpbuf_delete(buf);
     }
     return error;
 }
 
 static int
 dpif_linux_port_query_by_number(const struct dpif *dpif, uint16_t port_no,
-                                struct odp_port *port)
+                                struct dpif_port *dpif_port)
 {
-    memset(port, 0, sizeof *port);
-    port->port = port_no;
-    return dpif_linux_port_query__(dpif, port);
+    return dpif_linux_port_query__(dpif, port_no, NULL, dpif_port);
 }
 
 static int
 dpif_linux_port_query_by_name(const struct dpif *dpif, const char *devname,
-                              struct odp_port *port)
+                              struct dpif_port *dpif_port)
 {
-    memset(port, 0, sizeof *port);
-    strncpy(port->devname, devname, sizeof port->devname);
-    return dpif_linux_port_query__(dpif, port);
+    return dpif_linux_port_query__(dpif, 0, devname, dpif_port);
 }
 
 static int
@@ -323,26 +371,54 @@ dpif_linux_flow_flush(struct dpif *dpif_)
     return do_ioctl(dpif_, ODP_FLOW_FLUSH, NULL);
 }
 
+struct dpif_linux_port_state {
+    struct ofpbuf *buf;
+    uint32_t next;
+};
+
+static int
+dpif_linux_port_dump_start(const struct dpif *dpif OVS_UNUSED, void **statep)
+{
+    *statep = xzalloc(sizeof(struct dpif_linux_port_state));
+    return 0;
+}
+
 static int
-dpif_linux_port_list(const struct dpif *dpif_, struct odp_port *ports, int n)
+dpif_linux_port_dump_next(const struct dpif *dpif, void *state_,
+                          struct dpif_port *dpif_port)
 {
-    struct odp_portvec pv;
-    unsigned int i;
+    struct dpif_linux_port_state *state = state_;
+    struct dpif_linux_vport request, reply;
+    struct ofpbuf *buf;
     int error;
 
-    pv.ports = ports;
-    pv.n_ports = n;
-    error = do_ioctl(dpif_, ODP_VPORT_LIST, &pv);
+    ofpbuf_delete(state->buf);
+    state->buf = NULL;
+
+    dpif_linux_vport_init(&request);
+    request.cmd = ODP_VPORT_DUMP;
+    request.dp_idx = dpif_linux_cast(dpif)->minor;
+    request.port_no = state->next;
+    error = dpif_linux_vport_transact(&request, &reply, &buf);
     if (error) {
-        return -error;
+        return error == ENODEV ? EOF : error;
+    } else {
+        dpif_port->name = (char *) reply.name;
+        dpif_port->type = (char *) netdev_vport_get_netdev_type(&reply);
+        dpif_port->port_no = reply.port_no;
+        state->buf = buf;
+        state->next = reply.port_no + 1;
+        return 0;
     }
+}
 
-    for (i = 0; i < pv.n_ports; i++) {
-        struct odp_port *port = &pv.ports[i];
-
-        translate_vport_type_to_netdev_type(port);
-    }
-    return pv.n_ports;
+static int
+dpif_linux_port_dump_done(const struct dpif *dpif OVS_UNUSED, void *state_)
+{
+    struct dpif_linux_port_state *state = state_;
+    ofpbuf_delete(state->buf);
+    free(state);
+    return 0;
 }
 
 static int
@@ -585,7 +661,9 @@ const struct dpif_class dpif_linux_class = {
     dpif_linux_port_del,
     dpif_linux_port_query_by_number,
     dpif_linux_port_query_by_name,
-    dpif_linux_port_list,
+    dpif_linux_port_dump_start,
+    dpif_linux_port_dump_next,
+    dpif_linux_port_dump_done,
     dpif_linux_port_poll,
     dpif_linux_port_poll_wait,
     dpif_linux_flow_get,
@@ -615,61 +693,22 @@ do_ioctl(const struct dpif *dpif_, int cmd, const void *arg)
     return ioctl(dpif->fd, cmd, arg) ? errno : 0;
 }
 
-static int
-lookup_minor(const char *name, int *minorp)
+bool
+dpif_linux_is_internal_device(const char *name)
 {
-    struct ethtool_drvinfo drvinfo;
-    int minor, port_no;
-    struct ifreq ifr;
+    struct dpif_linux_vport reply;
+    struct ofpbuf *buf;
     int error;
-    int sock;
-
-    sock = socket(AF_INET, SOCK_DGRAM, 0);
-    if (sock < 0) {
-        VLOG_WARN("socket(AF_INET) failed: %s", strerror(errno));
-        error = errno;
-        goto error;
-    }
-
-    memset(&ifr, 0, sizeof ifr);
-    strncpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
-    ifr.ifr_data = (caddr_t) &drvinfo;
-
-    memset(&drvinfo, 0, sizeof drvinfo);
-    drvinfo.cmd = ETHTOOL_GDRVINFO;
-    if (ioctl(sock, SIOCETHTOOL, &ifr)) {
-        VLOG_WARN("ioctl(SIOCETHTOOL) failed: %s", strerror(errno));
-        error = errno;
-        goto error_close_sock;
-    }
-
-    if (strcmp(drvinfo.driver, "openvswitch")) {
-        VLOG_WARN("%s is not an openvswitch device", name);
-        error = EOPNOTSUPP;
-        goto error_close_sock;
-    }
 
-    if (sscanf(drvinfo.bus_info, "%d.%d", &minor, &port_no) != 2) {
-        VLOG_WARN("%s ethtool bus_info has unexpected format", name);
-        error = EPROTOTYPE;
-        goto error_close_sock;
-    } else if (port_no != ODPP_LOCAL) {
-        /* This is an Open vSwitch device but not the local port.  We
-         * intentionally support only using the name of the local port as the
-         * name of a datapath; otherwise, it would be too difficult to
-         * enumerate all the names of a datapath. */
-        error = EOPNOTSUPP;
-        goto error_close_sock;
+    error = dpif_linux_vport_get(name, &reply, &buf);
+    if (!error) {
+        ofpbuf_delete(buf);
+    } else if (error != ENODEV) {
+        VLOG_WARN_RL(&error_rl, "%s: vport query failed (%s)",
+                     name, strerror(error));
     }
 
-    *minorp = minor;
-    close(sock);
-    return 0;
-
-error_close_sock:
-    close(sock);
-error:
-    return error;
+    return reply.type == ODP_VPORT_TYPE_INTERNAL;
 }
 
 static int
@@ -791,78 +830,41 @@ get_major(const char *target)
 }
 
 static int
-finish_open(struct dpif *dpif_, const char *local_ifname)
+create_minor(const char *name, int minor)
 {
-    struct dpif_linux *dpif = dpif_linux_cast(dpif_);
-    dpif->local_ifname = xstrdup(local_ifname);
-    dpif->local_ifindex = if_nametoindex(local_ifname);
-    if (!dpif->local_ifindex) {
-        int error = errno;
-        dpif_uninit(dpif_, true);
-        VLOG_WARN("could not get ifindex of %s device: %s",
-                  local_ifname, strerror(errno));
+    int error;
+    int fd;
+
+    error = open_minor(minor, &fd);
+    if (error) {
         return error;
     }
-    return 0;
-}
 
-static int
-create_minor(const char *name, int minor, struct dpif **dpifp)
-{
-    int error = open_minor(minor, dpifp);
-    if (!error) {
-        error = do_ioctl(*dpifp, ODP_DP_CREATE, name);
-        if (!error) {
-            error = finish_open(*dpifp, name);
-        } else {
-            dpif_uninit(*dpifp, true);
-        }
-    }
+    error = ioctl(fd, ODP_DP_CREATE, name) ? errno : 0;
+    close(fd);
     return error;
 }
 
 static int
-open_minor(int minor, struct dpif **dpifp)
+open_minor(int minor, int *fdp)
 {
     int error;
     char *fn;
-    int fd;
 
     error = make_openvswitch_device(minor, &fn);
     if (error) {
         return error;
     }
 
-    fd = open(fn, O_RDONLY | O_NONBLOCK);
-    if (fd >= 0) {
-        struct dpif_linux *dpif = xmalloc(sizeof *dpif);
-        error = rtnetlink_link_notifier_register(&dpif->port_notifier,
-                                                 dpif_linux_port_changed,
-                                                 dpif);
-        if (!error) {
-            char *name;
-
-            name = xasprintf("dp%d", minor);
-            dpif_init(&dpif->dpif, &dpif_linux_class, name, minor, minor);
-            free(name);
-
-            dpif->fd = fd;
-            dpif->local_ifname = NULL;
-            dpif->minor = minor;
-            dpif->local_ifindex = 0;
-            shash_init(&dpif->changed_ports);
-            dpif->change_error = false;
-            *dpifp = &dpif->dpif;
-        } else {
-            free(dpif);
-        }
-    } else {
+    *fdp = open(fn, O_RDONLY | O_NONBLOCK);
+    if (*fdp < 0) {
         error = errno;
         VLOG_WARN("%s: open failed (%s)", fn, strerror(error));
+        free(fn);
+        return error;
     }
     free(fn);
-
-    return error;
+    return 0;
 }
 
 static void
@@ -884,3 +886,204 @@ dpif_linux_port_changed(const struct rtnetlink_link_change *change,
         dpif->change_error = true;
     }
 }
+
+/* Parses the contents of 'buf', which contains a "struct odp_vport" followed
+ * by Netlink attributes, into 'vport'.  Returns 0 if successful, otherwise a
+ * positive errno value.
+ *
+ * 'vport' will contain pointers into 'buf', so the caller should not free
+ * 'buf' while 'vport' is still in use. */
+static int
+dpif_linux_vport_from_ofpbuf(struct dpif_linux_vport *vport,
+                             const struct ofpbuf *buf)
+{
+    static const struct nl_policy odp_vport_policy[] = {
+        [ODP_VPORT_ATTR_PORT_NO] = { .type = NL_A_U32 },
+        [ODP_VPORT_ATTR_TYPE] = { .type = NL_A_U32 },
+        [ODP_VPORT_ATTR_NAME] = { .type = NL_A_STRING, .max_len = IFNAMSIZ },
+        [ODP_VPORT_ATTR_STATS] = { .type = NL_A_UNSPEC,
+                                   .min_len = sizeof(struct rtnl_link_stats64),
+                                   .max_len = sizeof(struct rtnl_link_stats64),
+                                   .optional = true },
+        [ODP_VPORT_ATTR_ADDRESS] = { .type = NL_A_UNSPEC,
+                                     .min_len = ETH_ADDR_LEN,
+                                     .max_len = ETH_ADDR_LEN,
+                                     .optional = true },
+        [ODP_VPORT_ATTR_MTU] = { .type = NL_A_U32, .optional = true },
+        [ODP_VPORT_ATTR_OPTIONS] = { .type = NL_A_NESTED, .optional = true },
+        [ODP_VPORT_ATTR_IFINDEX] = { .type = NL_A_U32, .optional = true },
+        [ODP_VPORT_ATTR_IFLINK] = { .type = NL_A_U32, .optional = true },
+    };
+
+    struct odp_vport *odp_vport;
+    struct nlattr *a[ARRAY_SIZE(odp_vport_policy)];
+
+    dpif_linux_vport_init(vport);
+
+    if (!nl_policy_parse(buf, sizeof *odp_vport, odp_vport_policy,
+                         a, ARRAY_SIZE(odp_vport_policy))) {
+        return EINVAL;
+    }
+    odp_vport = buf->data;
+
+    vport->dp_idx = odp_vport->dp_idx;
+    vport->port_no = nl_attr_get_u32(a[ODP_VPORT_ATTR_PORT_NO]);
+    vport->type = nl_attr_get_u32(a[ODP_VPORT_ATTR_TYPE]);
+    vport->name = nl_attr_get_string(a[ODP_VPORT_ATTR_NAME]);
+    if (a[ODP_VPORT_ATTR_STATS]) {
+        vport->stats = nl_attr_get(a[ODP_VPORT_ATTR_STATS]);
+    }
+    if (a[ODP_VPORT_ATTR_ADDRESS]) {
+        vport->address = nl_attr_get(a[ODP_VPORT_ATTR_ADDRESS]);
+    }
+    if (a[ODP_VPORT_ATTR_MTU]) {
+        vport->mtu = nl_attr_get_u32(a[ODP_VPORT_ATTR_MTU]);
+    }
+    if (a[ODP_VPORT_ATTR_OPTIONS]) {
+        vport->options = nl_attr_get(a[ODP_VPORT_ATTR_OPTIONS]);
+        vport->options_len = nl_attr_get_size(a[ODP_VPORT_ATTR_OPTIONS]);
+    }
+    if (a[ODP_VPORT_ATTR_IFINDEX]) {
+        vport->ifindex = nl_attr_get_u32(a[ODP_VPORT_ATTR_IFINDEX]);
+    }
+    if (a[ODP_VPORT_ATTR_IFLINK]) {
+        vport->iflink = nl_attr_get_u32(a[ODP_VPORT_ATTR_IFLINK]);
+    }
+    return 0;
+}
+
+/* Appends to 'buf' (which must initially be empty) a "struct odp_vport"
+ * followed by Netlink attributes corresponding to 'vport'. */
+static void
+dpif_linux_vport_to_ofpbuf(const struct dpif_linux_vport *vport,
+                           struct ofpbuf *buf)
+{
+    struct odp_vport *odp_vport;
+
+    ofpbuf_reserve(buf, sizeof odp_vport);
+
+    if (vport->port_no != UINT32_MAX) {
+        nl_msg_put_u32(buf, ODP_VPORT_ATTR_PORT_NO, vport->port_no);
+    }
+
+    if (vport->type != ODP_VPORT_TYPE_UNSPEC) {
+        nl_msg_put_u32(buf, ODP_VPORT_ATTR_TYPE, vport->type);
+    }
+
+    if (vport->name) {
+        nl_msg_put_string(buf, ODP_VPORT_ATTR_NAME, vport->name);
+    }
+
+    if (vport->stats) {
+        nl_msg_put_unspec(buf, ODP_VPORT_ATTR_STATS,
+                          vport->stats, sizeof *vport->stats);
+    }
+
+    if (vport->address) {
+        nl_msg_put_unspec(buf, ODP_VPORT_ATTR_ADDRESS,
+                          vport->address, ETH_ADDR_LEN);
+    }
+
+    if (vport->mtu) {
+        nl_msg_put_u32(buf, ODP_VPORT_ATTR_MTU, vport->mtu);
+    }
+
+    if (vport->options) {
+        nl_msg_put_nested(buf, ODP_VPORT_ATTR_OPTIONS,
+                          vport->options, vport->options_len);
+    }
+
+    if (vport->ifindex) {
+        nl_msg_put_u32(buf, ODP_VPORT_ATTR_IFINDEX, vport->ifindex);
+    }
+
+    if (vport->iflink) {
+        nl_msg_put_u32(buf, ODP_VPORT_ATTR_IFLINK, vport->iflink);
+    }
+
+    odp_vport = ofpbuf_push_uninit(buf, sizeof *odp_vport);
+    odp_vport->dp_idx = vport->dp_idx;
+    odp_vport->len = buf->size;
+    odp_vport->total_len = (char *) ofpbuf_end(buf) - (char *) buf->data;
+}
+
+/* Clears 'vport' to "empty" values. */
+void
+dpif_linux_vport_init(struct dpif_linux_vport *vport)
+{
+    memset(vport, 0, sizeof *vport);
+    vport->dp_idx = UINT32_MAX;
+    vport->port_no = UINT32_MAX;
+}
+
+/* Executes 'request' in the kernel datapath.  If the command fails, returns a
+ * positive errno value.  Otherwise, if 'reply' and 'bufp' are null, returns 0
+ * without doing anything else.  If 'reply' and 'bufp' are nonnull, then the
+ * result of the command is expected to be an odp_vport also, which is decoded
+ * and stored in '*reply' and '*bufp'.  The caller must free '*bufp' when the
+ * reply is no longer needed ('reply' will contain pointers into '*bufp'). */
+int
+dpif_linux_vport_transact(const struct dpif_linux_vport *request,
+                          struct dpif_linux_vport *reply,
+                          struct ofpbuf **bufp)
+{
+    static int dp0_fd = -1;
+    struct ofpbuf *buf = NULL;
+    int error;
+
+    assert((reply != NULL) == (bufp != NULL));
+    if (dp0_fd < 0) {
+        int fd;
+
+        error = open_minor(0, &fd);
+        if (error) {
+            goto error;
+        }
+        dp0_fd = fd;
+    }
+
+    buf = ofpbuf_new(1024);
+    dpif_linux_vport_to_ofpbuf(request, buf);
+
+    error = ioctl(dp0_fd, request->cmd, buf->data) ? errno : 0;
+    if (error) {
+        goto error;
+    }
+
+    if (bufp) {
+        buf->size = ((struct odp_vport *) buf->data)->len;
+        error = dpif_linux_vport_from_ofpbuf(reply, buf);
+        if (error) {
+            goto error;
+        }
+        *bufp = buf;
+    } else {
+        ofpbuf_delete(buf);
+    }
+    return 0;
+
+error:
+    ofpbuf_delete(buf);
+    if (bufp) {
+        memset(reply, 0, sizeof *reply);
+        *bufp = NULL;
+    }
+    return error;
+}
+
+/* Obtains information about the kernel vport named 'name' and stores it into
+ * '*reply' and '*bufp'.  The caller must free '*bufp' when the reply is no
+ * longer needed ('reply' will contain pointers into '*bufp').  */
+int
+dpif_linux_vport_get(const char *name, struct dpif_linux_vport *reply,
+                     struct ofpbuf **bufp)
+{
+    struct dpif_linux_vport request;
+
+    dpif_linux_vport_init(&request);
+    request.cmd = ODP_VPORT_GET;
+    request.name = name;
+
+    return dpif_linux_vport_transact(&request, reply, bufp);
+}
+