ovs/lib/dpif-netlink-rtnl.c

/*
 * Copyright (c) 2017 Red Hat, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <config.h>

#include "dpif-netlink-rtnl.h"

#include <net/if.h>
#include <linux/ip.h>
#include <linux/rtnetlink.h>

#include "dpif-netlink.h"
#include "netdev-vport.h"
#include "netlink-socket.h"
#include "openvswitch/vlog.h"

VLOG_DEFINE_THIS_MODULE(dpif_netlink_rtnl);

/* On some older systems, these enums are not defined. */
#ifndef IFLA_VXLAN_MAX
#define IFLA_VXLAN_MAX 0
#endif
#if IFLA_VXLAN_MAX < 25
#define IFLA_VXLAN_LEARNING 7
#define IFLA_VXLAN_PORT 15
#define IFLA_VXLAN_UDP_ZERO_CSUM6_RX 20
#define IFLA_VXLAN_GBP 23
#define IFLA_VXLAN_COLLECT_METADATA 25
#endif

static const struct nl_policy rtlink_policy[] = {
    [IFLA_LINKINFO] = { .type = NL_A_NESTED },
};
static const struct nl_policy linkinfo_policy[] = {
    [IFLA_INFO_KIND] = { .type = NL_A_STRING },
    [IFLA_INFO_DATA] = { .type = NL_A_NESTED },
};
static const struct nl_policy vxlan_policy[] = {
    [IFLA_VXLAN_COLLECT_METADATA] = { .type = NL_A_U8 },
    [IFLA_VXLAN_LEARNING] = { .type = NL_A_U8 },
    [IFLA_VXLAN_UDP_ZERO_CSUM6_RX] = { .type = NL_A_U8 },
    [IFLA_VXLAN_PORT] = { .type = NL_A_U16 },
};

static const char *
vport_type_to_kind(enum ovs_vport_type type)
{
    switch (type) {
    case OVS_VPORT_TYPE_VXLAN:
        return "vxlan";
    case OVS_VPORT_TYPE_GRE:
        return "gretap";
    case OVS_VPORT_TYPE_GENEVE:
        return "geneve";
    case OVS_VPORT_TYPE_NETDEV:
    case OVS_VPORT_TYPE_INTERNAL:
    case OVS_VPORT_TYPE_LISP:
    case OVS_VPORT_TYPE_STT:
    case OVS_VPORT_TYPE_UNSPEC:
    case __OVS_VPORT_TYPE_MAX:
    default:
        break;
    }

    return NULL;
}

static int
rtnl_transact(uint32_t type, uint32_t flags, const char *name,
              struct ofpbuf **reply)
{
    struct ofpbuf request;
    int err;

    ofpbuf_init(&request, 0);
    nl_msg_put_nlmsghdr(&request, 0, type, flags);
    ofpbuf_put_zeros(&request, sizeof(struct ifinfomsg));
    nl_msg_put_string(&request, IFLA_IFNAME, name);

    err = nl_transact(NETLINK_ROUTE, &request, reply);
    ofpbuf_uninit(&request);

    return err;
}

static int
dpif_netlink_rtnl_destroy(const char *name)
{
    return rtnl_transact(RTM_DELLINK, NLM_F_REQUEST | NLM_F_ACK, name, NULL);
}

static int
dpif_netlink_rtnl_getlink(const char *name, struct ofpbuf **reply)
{
    return rtnl_transact(RTM_GETLINK, NLM_F_REQUEST, name, reply);
}

static int
rtnl_policy_parse(const char *kind, struct ofpbuf *reply,
                  const struct nl_policy *policy,
                  struct nlattr *tnl_info[],
                  size_t policy_size)
{
    struct nlattr *linkinfo[ARRAY_SIZE(linkinfo_policy)];
    struct nlattr *rtlink[ARRAY_SIZE(rtlink_policy)];
    struct ifinfomsg *ifmsg;
    int error = 0;

    ifmsg = ofpbuf_at(reply, NLMSG_HDRLEN, sizeof *ifmsg);
    if (!nl_policy_parse(reply, NLMSG_HDRLEN + sizeof *ifmsg,
                         rtlink_policy, rtlink, ARRAY_SIZE(rtlink_policy))
        || !nl_parse_nested(rtlink[IFLA_LINKINFO], linkinfo_policy,
                            linkinfo, ARRAY_SIZE(linkinfo_policy))
        || strcmp(nl_attr_get_string(linkinfo[IFLA_INFO_KIND]), kind)
        || !nl_parse_nested(linkinfo[IFLA_INFO_DATA], policy,
                            tnl_info, policy_size)) {
        error = EINVAL;
    }

    return error;
}

static int
dpif_netlink_rtnl_vxlan_verify(const struct netdev_tunnel_config *tnl_cfg,
                               const char *name, const char *kind)
{
    struct ofpbuf *reply;
    int err;

    err = dpif_netlink_rtnl_getlink(name, &reply);

    if (!err) {
        struct nlattr *vxlan[ARRAY_SIZE(vxlan_policy)];

        err = rtnl_policy_parse(kind, reply, vxlan_policy, vxlan,
                                ARRAY_SIZE(vxlan_policy));
        if (!err) {
            if (0 != nl_attr_get_u8(vxlan[IFLA_VXLAN_LEARNING])
                || 1 != nl_attr_get_u8(vxlan[IFLA_VXLAN_COLLECT_METADATA])
                || 1 != nl_attr_get_u8(vxlan[IFLA_VXLAN_UDP_ZERO_CSUM6_RX])
                || (tnl_cfg->dst_port
                    != nl_attr_get_be16(vxlan[IFLA_VXLAN_PORT]))) {
                err = EINVAL;
            }
        }
        if (!err) {
            if (tnl_cfg->exts & (1 << OVS_VXLAN_EXT_GBP)
                && !nl_attr_get_flag(vxlan[IFLA_VXLAN_GBP])) {
                err = EINVAL;
            }
        }
        ofpbuf_delete(reply);
    }

    return err;
}


static int
dpif_netlink_rtnl_verify(const struct netdev_tunnel_config *tnl_cfg,
                         enum ovs_vport_type type, const char *name)
{
    const char *kind;

    kind = vport_type_to_kind(type);
    if (!kind) {
        return EOPNOTSUPP;
    }

    switch (type) {
    case OVS_VPORT_TYPE_VXLAN:
        return dpif_netlink_rtnl_vxlan_verify(tnl_cfg, name, kind);
    case OVS_VPORT_TYPE_GRE:
    case OVS_VPORT_TYPE_GENEVE:
    case OVS_VPORT_TYPE_NETDEV:
    case OVS_VPORT_TYPE_INTERNAL:
    case OVS_VPORT_TYPE_LISP:
    case OVS_VPORT_TYPE_STT:
    case OVS_VPORT_TYPE_UNSPEC:
    case __OVS_VPORT_TYPE_MAX:
    default:
        return EOPNOTSUPP;
    }

    return 0;
}

static int
dpif_netlink_rtnl_create(const struct netdev_tunnel_config *tnl_cfg,
                         const char *name, enum ovs_vport_type type,
                         const char *kind, uint32_t flags)
{
    size_t linkinfo_off, infodata_off;
    struct ifinfomsg *ifinfo;
    struct ofpbuf request;
    int err;

    ofpbuf_init(&request, 0);
    nl_msg_put_nlmsghdr(&request, 0, RTM_NEWLINK, flags);
    ifinfo = ofpbuf_put_zeros(&request, sizeof(struct ifinfomsg));
    ifinfo->ifi_change = ifinfo->ifi_flags = IFF_UP;
    nl_msg_put_string(&request, IFLA_IFNAME, name);
    nl_msg_put_u32(&request, IFLA_MTU, UINT16_MAX);
    linkinfo_off = nl_msg_start_nested(&request, IFLA_LINKINFO);
    nl_msg_put_string(&request, IFLA_INFO_KIND, kind);
    infodata_off = nl_msg_start_nested(&request, IFLA_INFO_DATA);

    /* tunnel unique info */
    switch (type) {
    case OVS_VPORT_TYPE_VXLAN:
        nl_msg_put_u8(&request, IFLA_VXLAN_LEARNING, 0);
        nl_msg_put_u8(&request, IFLA_VXLAN_COLLECT_METADATA, 1);
        nl_msg_put_u8(&request, IFLA_VXLAN_UDP_ZERO_CSUM6_RX, 1);
        if (tnl_cfg->exts & (1 << OVS_VXLAN_EXT_GBP)) {
            nl_msg_put_flag(&request, IFLA_VXLAN_GBP);
        }
        nl_msg_put_be16(&request, IFLA_VXLAN_PORT, tnl_cfg->dst_port);
        break;
    case OVS_VPORT_TYPE_GRE:
    case OVS_VPORT_TYPE_GENEVE:
    case OVS_VPORT_TYPE_NETDEV:
    case OVS_VPORT_TYPE_INTERNAL:
    case OVS_VPORT_TYPE_LISP:
    case OVS_VPORT_TYPE_STT:
    case OVS_VPORT_TYPE_UNSPEC:
    case __OVS_VPORT_TYPE_MAX:
    default:
        err = EOPNOTSUPP;
        goto exit;
    }

    nl_msg_end_nested(&request, infodata_off);
    nl_msg_end_nested(&request, linkinfo_off);

    err = nl_transact(NETLINK_ROUTE, &request, NULL);

exit:
    ofpbuf_uninit(&request);

    return err;
}

int
dpif_netlink_rtnl_port_create(struct netdev *netdev)
{
    const struct netdev_tunnel_config *tnl_cfg;
    char namebuf[NETDEV_VPORT_NAME_BUFSIZE];
    enum ovs_vport_type type;
    const char *name;
    const char *kind;
    uint32_t flags;
    int err;

    type = netdev_to_ovs_vport_type(netdev_get_type(netdev));
    kind = vport_type_to_kind(type);
    if (!kind) {
        return EOPNOTSUPP;
    }

    tnl_cfg = netdev_get_tunnel_config(netdev);
    if (!tnl_cfg) {
        return EINVAL;
    }

    name = netdev_vport_get_dpif_port(netdev, namebuf, sizeof namebuf);
    flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | NLM_F_EXCL;

    err = dpif_netlink_rtnl_create(tnl_cfg, name, type, kind, flags);

    /* If the device exists, validate and/or attempt to recreate it. */
    if (err == EEXIST) {
        err = dpif_netlink_rtnl_verify(tnl_cfg, type, name);
        if (!err) {
            return 0;
        } else {
            err = dpif_netlink_rtnl_destroy(name);
            if (err) {
                static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);

                VLOG_WARN_RL(&rl, "RTNL device %s exists and cannot be "
                             "deleted: %s", name, ovs_strerror(err));
                return err;
            }
            err = dpif_netlink_rtnl_create(tnl_cfg, name, type, kind, flags);
        }
    }
    if (err) {
        return err;
    }

    err = dpif_netlink_rtnl_verify(tnl_cfg, type, name);
    if (err) {
        int err2 = dpif_netlink_rtnl_destroy(name);

        if (err2) {
            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);

            VLOG_WARN_RL(&rl, "Failed to delete device %s during rtnl port "
                         "creation: %s", name, ovs_strerror(err2));
        }
    }

    return err;
}

int
dpif_netlink_rtnl_port_destroy(const char *name, const char *type)
{
    switch (netdev_to_ovs_vport_type(type)) {
    case OVS_VPORT_TYPE_VXLAN:
        return dpif_netlink_rtnl_destroy(name);
    case OVS_VPORT_TYPE_GRE:
    case OVS_VPORT_TYPE_GENEVE:
    case OVS_VPORT_TYPE_NETDEV:
    case OVS_VPORT_TYPE_INTERNAL:
    case OVS_VPORT_TYPE_LISP:
    case OVS_VPORT_TYPE_STT:
    case OVS_VPORT_TYPE_UNSPEC:
    case __OVS_VPORT_TYPE_MAX:
    default:
        return EOPNOTSUPP;
    }
    return 0;
}