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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* netconf_netlink.c - netconf interaction with the kernel using
* netlink
* Copyright (C) 2021 Nvidia, Inc.
* Donald Sharp
*/
#include <zebra.h>
#include <fcntl.h>
#ifdef HAVE_NETLINK /* Netlink OSes only */
#include <ns.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include "linux/netconf.h"
#include "lib/lib_errors.h"
#include "zebra/zebra_ns.h"
#include "zebra/zebra_dplane.h"
#include "zebra/kernel_netlink.h"
#include "zebra/netconf_netlink.h"
#include "zebra/debug.h"
static struct rtattr *netconf_rta(struct netconfmsg *ncm)
{
return (struct rtattr *)((char *)ncm +
NLMSG_ALIGN(sizeof(struct netconfmsg)));
}
/*
* Handle netconf update about a single interface: create dplane
* context, and enqueue for processing in the main zebra pthread.
*/
static int
netlink_netconf_dplane_update(ns_id_t ns_id, afi_t afi, ifindex_t ifindex,
enum dplane_netconf_status_e mpls_on,
enum dplane_netconf_status_e mcast_on,
enum dplane_netconf_status_e linkdown_on)
{
struct zebra_dplane_ctx *ctx;
ctx = dplane_ctx_alloc();
dplane_ctx_set_op(ctx, DPLANE_OP_INTF_NETCONFIG);
dplane_ctx_set_ns_id(ctx, ns_id);
dplane_ctx_set_afi(ctx, afi);
dplane_ctx_set_ifindex(ctx, ifindex);
dplane_ctx_set_netconf_mpls(ctx, mpls_on);
dplane_ctx_set_netconf_mcast(ctx, mcast_on);
dplane_ctx_set_netconf_linkdown(ctx, linkdown_on);
/* Enqueue ctx for main pthread to process */
dplane_provider_enqueue_to_zebra(ctx);
return 0;
}
/*
* Parse and process an incoming netlink netconf update.
*/
int netlink_netconf_change(struct nlmsghdr *h, ns_id_t ns_id, int startup)
{
struct netconfmsg *ncm;
struct rtattr *tb[NETCONFA_MAX + 1] = {};
int len;
ifindex_t ifindex;
uint32_t ival;
afi_t afi;
enum dplane_netconf_status_e mpls_on = DPLANE_NETCONF_STATUS_UNKNOWN;
enum dplane_netconf_status_e mcast_on = DPLANE_NETCONF_STATUS_UNKNOWN;
enum dplane_netconf_status_e linkdown_on =
DPLANE_NETCONF_STATUS_UNKNOWN;
if (h->nlmsg_type != RTM_NEWNETCONF && h->nlmsg_type != RTM_DELNETCONF)
return 0;
len = h->nlmsg_len - NLMSG_LENGTH(sizeof(struct netconfmsg));
if (len < 0) {
zlog_err("%s: Message received from netlink is of a broken size: %d, min %zu",
__func__, h->nlmsg_len,
(size_t)NLMSG_LENGTH(sizeof(struct netconfmsg)));
return -1;
}
ncm = NLMSG_DATA(h);
/*
* FRR does not have an internal representation of afi_t for
* the MPLS Address Family that the kernel has. So let's
* just call it v4. This is ok because the kernel appears
* to do a good job of not sending data that is mixed/matched
* across families
*/
#ifdef AF_MPLS
if (ncm->ncm_family == AF_MPLS)
afi = AFI_IP;
else
#endif /* AF_MPLS */
afi = family2afi(ncm->ncm_family);
netlink_parse_rtattr(tb, NETCONFA_MAX, netconf_rta(ncm), len);
if (!tb[NETCONFA_IFINDEX]) {
zlog_err("NETCONF message received from netlink without an ifindex");
return 0;
}
ifindex = *(ifindex_t *)RTA_DATA(tb[NETCONFA_IFINDEX]);
if (tb[NETCONFA_INPUT]) {
ival = *(uint32_t *)RTA_DATA(tb[NETCONFA_INPUT]);
if (ival != 0)
mpls_on = DPLANE_NETCONF_STATUS_ENABLED;
else
mpls_on = DPLANE_NETCONF_STATUS_DISABLED;
}
if (tb[NETCONFA_MC_FORWARDING]) {
ival = *(uint32_t *)RTA_DATA(tb[NETCONFA_MC_FORWARDING]);
if (ival != 0)
mcast_on = DPLANE_NETCONF_STATUS_ENABLED;
else
mcast_on = DPLANE_NETCONF_STATUS_DISABLED;
}
if (tb[NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]) {
ival = *(uint32_t *)RTA_DATA(
tb[NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN]);
if (ival != 0)
linkdown_on = DPLANE_NETCONF_STATUS_ENABLED;
else
linkdown_on = DPLANE_NETCONF_STATUS_DISABLED;
}
if (IS_ZEBRA_DEBUG_KERNEL)
zlog_debug(
"%s: interface %u is mpls on: %d multicast on: %d linkdown: %d",
__func__, ifindex, mpls_on, mcast_on, linkdown_on);
/* Create a dplane context and pass it along for processing */
netlink_netconf_dplane_update(ns_id, afi, ifindex, mpls_on, mcast_on,
linkdown_on);
return 0;
}
/*
* Request info from the host OS. This only sends the request; any replies
* are processed asynchronously.
*/
int netlink_request_netconf(int sockfd)
{
struct nlsock *nls;
struct {
struct nlmsghdr n;
struct netconfmsg ncm;
char buf[1024];
} req = {};
nls = kernel_netlink_nlsock_lookup(sockfd);
if (IS_ZEBRA_DEBUG_KERNEL)
zlog_debug("%s: nlsock %s", __func__, nls ? nls->name : "NULL");
if (nls == NULL)
return -1;
req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct netconfmsg));
req.n.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
req.n.nlmsg_type = RTM_GETNETCONF;
req.ncm.ncm_family = AF_UNSPEC;
return netlink_request(nls, &req);
}
extern struct zebra_privs_t zserv_privs;
/*
* Currently netconf has no ability to set from netlink.
* So we've received a request to do this work in the data plane.
* as such we need to set the value via the /proc system
*/
enum netlink_msg_status netlink_put_intf_netconfig(struct nl_batch *bth,
struct zebra_dplane_ctx *ctx)
{
const char *ifname = dplane_ctx_get_ifname(ctx);
enum dplane_netconf_status_e mpls_on = dplane_ctx_get_netconf_mpls(ctx);
char set[64];
char mpls_proc[PATH_MAX];
int fd, ret = FRR_NETLINK_ERROR;
snprintf(mpls_proc, sizeof(mpls_proc),
"/proc/sys/net/mpls/conf/%s/input", ifname);
if (mpls_on == DPLANE_NETCONF_STATUS_ENABLED)
snprintf(set, sizeof(set), "1\n");
else if (mpls_on == DPLANE_NETCONF_STATUS_DISABLED)
snprintf(set, sizeof(set), "0\n");
else {
flog_err_sys(
EC_LIB_DEVELOPMENT,
"%s: Expected interface %s to be set to ENABLED or DISABLED was %d",
__func__, ifname, mpls_on);
return ret;
}
frr_with_privs (&zserv_privs) {
fd = open(mpls_proc, O_WRONLY);
if (fd < 0) {
flog_err_sys(
EC_LIB_SOCKET,
"%s: Unable to open %s for writing: %s(%d)",
__func__, mpls_proc, safe_strerror(errno),
errno);
return ret;
}
if (write(fd, set, 2) == 2)
ret = FRR_NETLINK_SUCCESS;
else
flog_err_sys(EC_LIB_SOCKET,
"%s: Unsuccessful write to %s: %s(%d)",
__func__, mpls_proc, safe_strerror(errno),
errno);
close(fd);
}
return ret;
}
#endif /* HAVE_NETLINK */
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