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sys/netlink/route/nexthop.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2022 Alexander V. Chernikov
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/rmlock.h>
#include <sys/socket.h>
#include <sys/ck.h>
#include <net/if.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/route/nhop_utils.h>
#include <net/route/route_ctl.h>
#include <net/route/route_var.h>
#include <netinet6/scope6_var.h>
#include <netlink/netlink.h>
#include <netlink/netlink_ctl.h>
#include <netlink/netlink_var.h>
#include <netlink/netlink_route.h>
#include <netlink/route/route_var.h>
#define DEBUG_MOD_NAME nl_nhop
#define DEBUG_MAX_LEVEL LOG_DEBUG3
#include <netlink/netlink_debug.h>
_DECLARE_DEBUG(LOG_DEBUG3);
/*
* This file contains the logic to maintain kernel nexthops and
* nexhop groups based om the data provided by the user.
*
* Kernel stores (nearly) all of the routing data in the nexthops,
* including the prefix-specific flags (NHF_HOST and NHF_DEFAULT).
*
* Netlink API provides higher-level abstraction for the user. Each
* user-created nexthop may map to multiple kernel nexthops.
*
* The following variations require separate kernel nexthop to be
* created:
* * prefix flags (NHF_HOST, NHF_DEFAULT)
* * using IPv6 gateway for IPv4 routes
* * different fibnum
*
* These kernel nexthops have the lifetime bound to the lifetime of
* the user_nhop object. They are not collected until user requests
* to delete the created user_nhop.
*
*/
struct user_nhop {
uint32_t un_idx; /* Userland-provided index */
uint32_t un_fibfam; /* fibnum+af(as highest byte) */
uint8_t un_protocol; /* protocol that install the record */
struct nhop_object *un_nhop; /* "production" nexthop */
struct nhop_object *un_nhop_src; /* nexthop to copy from */
struct weightened_nhop *un_nhgrp_src; /* nexthops for nhg */
uint32_t un_nhgrp_count; /* number of nexthops */
struct user_nhop *un_next; /* next item in hash chain */
struct user_nhop *un_nextchild; /* master -> children */
struct epoch_context un_epoch_ctx; /* epoch ctl helper */
};
/* produce hash value for an object */
#define unhop_hash_obj(_obj) (hash_unhop(_obj))
/* compare two objects */
#define unhop_cmp(_one, _two) (cmp_unhop(_one, _two))
/* next object accessor */
#define unhop_next(_obj) (_obj)->un_next
CHT_SLIST_DEFINE(unhop, struct user_nhop);
struct unhop_ctl {
struct unhop_head un_head;
struct rmlock un_lock;
};
#define UN_LOCK_INIT(_ctl) rm_init(&(_ctl)->un_lock, "unhop_ctl")
#define UN_TRACKER struct rm_priotracker un_tracker
#define UN_RLOCK(_ctl) rm_rlock(&((_ctl)->un_lock), &un_tracker)
#define UN_RUNLOCK(_ctl) rm_runlock(&((_ctl)->un_lock), &un_tracker)
#define UN_WLOCK(_ctl) rm_wlock(&(_ctl)->un_lock);
#define UN_WUNLOCK(_ctl) rm_wunlock(&(_ctl)->un_lock);
VNET_DEFINE_STATIC(struct unhop_ctl *, un_ctl) = NULL;
#define V_un_ctl VNET(un_ctl)
static void consider_resize(struct unhop_ctl *ctl, uint32_t new_size);
static int cmp_unhop(const struct user_nhop *a, const struct user_nhop *b);
static unsigned int hash_unhop(const struct user_nhop *obj);
static void destroy_unhop(struct user_nhop *unhop);
static struct nhop_object *clone_unhop(const struct user_nhop *unhop,
uint32_t fibnum, int family, int nh_flags);
static int
cmp_unhop(const struct user_nhop *a, const struct user_nhop *b)
{
return (a->un_idx == b->un_idx && a->un_fibfam == b->un_fibfam);
}
/*
* Hash callback: calculate hash of an object
*/
static unsigned int
hash_unhop(const struct user_nhop *obj)
{
return (obj->un_idx ^ obj->un_fibfam);
}
#define UNHOP_IS_MASTER(_unhop) ((_unhop)->un_fibfam == 0)
/*
* Factory interface for creating matching kernel nexthops/nexthop groups
*
* @uidx: userland nexhop index used to create the nexthop
* @fibnum: fibnum nexthop will be used in
* @family: upper family nexthop will be used in
* @nh_flags: desired nexthop prefix flags
* @perror: pointer to store error to
*
* Returns referenced nexthop linked to @fibnum/@family rib on success.
*/
struct nhop_object *
nl_find_nhop(uint32_t fibnum, int family, uint32_t uidx,
int nh_flags, int *perror)
{
struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
UN_TRACKER;
if (__predict_false(ctl == NULL))
return (NULL);
struct user_nhop key= {
.un_idx = uidx,
.un_fibfam = fibnum | ((uint32_t)family) << 24,
};
struct user_nhop *unhop;
nh_flags = nh_flags & (NHF_HOST | NHF_DEFAULT);
if (__predict_false(family == 0))
return (NULL);
UN_RLOCK(ctl);
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
if (unhop != NULL) {
struct nhop_object *nh = unhop->un_nhop;
UN_RLOCK(ctl);
*perror = 0;
nhop_ref_any(nh);
return (nh);
}
/*
* Exact nexthop not found. Search for template nexthop to clone from.
*/
key.un_fibfam = 0;
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
if (unhop == NULL) {
UN_RUNLOCK(ctl);
*perror = ESRCH;
return (NULL);
}
UN_RUNLOCK(ctl);
/* Create entry to insert first */
struct user_nhop *un_new, *un_tmp;
un_new = malloc(sizeof(struct user_nhop), M_NETLINK, M_NOWAIT | M_ZERO);
if (un_new == NULL) {
*perror = ENOMEM;
return (NULL);
}
un_new->un_idx = uidx;
un_new->un_fibfam = fibnum | ((uint32_t)family) << 24;
/* Relying on epoch to protect unhop here */
un_new->un_nhop = clone_unhop(unhop, fibnum, family, nh_flags);
if (un_new->un_nhop == NULL) {
free(un_new, M_NETLINK);
*perror = ENOMEM;
return (NULL);
}
/* Insert back and report */
UN_WLOCK(ctl);
/* First, find template record once again */
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
if (unhop == NULL) {
/* Someone deleted the nexthop during the call */
UN_WUNLOCK(ctl);
*perror = ESRCH;
destroy_unhop(un_new);
return (NULL);
}
/* Second, check the direct match */
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, un_new, un_tmp);
struct nhop_object *nh;
if (un_tmp != NULL) {
/* Another thread already created the desired nextop, use it */
nh = un_tmp->un_nhop;
} else {
/* Finally, insert the new nexthop and link it to the primary */
nh = un_new->un_nhop;
CHT_SLIST_INSERT_HEAD(&ctl->un_head, unhop, un_new);
un_new->un_nextchild = unhop->un_nextchild;
unhop->un_nextchild = un_new;
un_new = NULL;
NL_LOG(LOG_DEBUG2, "linked cloned nexthop %p", nh);
}
UN_WUNLOCK(ctl);
if (un_new != NULL)
destroy_unhop(un_new);
*perror = 0;
nhop_ref_any(nh);
return (nh);
}
static struct user_nhop *
nl_find_base_unhop(struct unhop_ctl *ctl, uint32_t uidx)
{
struct user_nhop key= { .un_idx = uidx };
struct user_nhop *unhop = NULL;
UN_TRACKER;
UN_RLOCK(ctl);
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
UN_RUNLOCK(ctl);
return (unhop);
}
#define MAX_STACK_NHOPS 4
static struct nhop_object *
clone_unhop(const struct user_nhop *unhop, uint32_t fibnum, int family, int nh_flags)
{
const struct weightened_nhop *wn;
struct weightened_nhop *wn_new, wn_base[MAX_STACK_NHOPS];
struct nhop_object *nh = NULL;
uint32_t num_nhops;
int error;
if (unhop->un_nhop_src != NULL) {
IF_DEBUG_LEVEL(LOG_DEBUG2) {
char nhbuf[NHOP_PRINT_BUFSIZE];
nhop_print_buf_any(unhop->un_nhop_src, nhbuf, sizeof(nhbuf));
FIB_NH_LOG(LOG_DEBUG2, unhop->un_nhop_src,
"cloning nhop %s -> %u.%u flags 0x%X", nhbuf, fibnum,
family, nh_flags);
}
struct nhop_object *nh;
nh = nhop_alloc(fibnum, AF_UNSPEC);
if (nh == NULL)
return (NULL);
nhop_copy(nh, unhop->un_nhop_src);
/* Check that nexthop gateway is compatible with the new family */
if (!nhop_set_upper_family(nh, family)) {
nhop_free(nh);
return (NULL);
}
nhop_set_uidx(nh, unhop->un_idx);
nhop_set_pxtype_flag(nh, nh_flags);
return (nhop_get_nhop(nh, &error));
}
wn = unhop->un_nhgrp_src;
num_nhops = unhop->un_nhgrp_count;
if (num_nhops > MAX_STACK_NHOPS) {
wn_new = malloc(num_nhops * sizeof(struct weightened_nhop), M_TEMP, M_NOWAIT);
if (wn_new == NULL)
return (NULL);
} else
wn_new = wn_base;
for (int i = 0; i < num_nhops; i++) {
uint32_t uidx = nhop_get_uidx(wn[i].nh);
MPASS(uidx != 0);
wn_new[i].nh = nl_find_nhop(fibnum, family, uidx, nh_flags, &error);
if (error != 0)
break;
wn_new[i].weight = wn[i].weight;
}
if (error == 0) {
struct rib_head *rh = nhop_get_rh(wn_new[0].nh);
struct nhgrp_object *nhg;
error = nhgrp_get_group(rh, wn_new, num_nhops, unhop->un_idx, &nhg);
nh = (struct nhop_object *)nhg;
}
if (wn_new != wn_base)
free(wn_new, M_TEMP);
return (nh);
}
static void
destroy_unhop(struct user_nhop *unhop)
{
if (unhop->un_nhop != NULL)
nhop_free_any(unhop->un_nhop);
if (unhop->un_nhop_src != NULL)
nhop_free_any(unhop->un_nhop_src);
free(unhop, M_NETLINK);
}
static void
destroy_unhop_epoch(epoch_context_t ctx)
{
struct user_nhop *unhop;
unhop = __containerof(ctx, struct user_nhop, un_epoch_ctx);
destroy_unhop(unhop);
}
static uint32_t
find_spare_uidx(struct unhop_ctl *ctl)
{
struct user_nhop *unhop, key = {};
uint32_t uidx = 0;
UN_TRACKER;
UN_RLOCK(ctl);
/* This should return spare uid with 75% of 65k used in ~99/100 cases */
for (int i = 0; i < 16; i++) {
key.un_idx = (arc4random() % 65536) + 65536 * 4;
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
if (unhop == NULL) {
uidx = key.un_idx;
break;
}
}
UN_RUNLOCK(ctl);
return (uidx);
}
/*
* Actual netlink code
*/
struct netlink_walkargs {
struct nlmsg_state *ns;
struct nlmsghdr hdr;
struct nlpcb *so;
int family;
int error;
int count;
int dumped;
};
#define ENOMEM_IF_NULL(_v) if ((_v) == NULL) goto enomem
static bool
dump_nhgrp(const struct user_nhop *unhop, struct nlmsghdr *hdr,
struct nlmsg_state *ns)
{
if (!nlmsg_reply(ns, hdr, sizeof(struct nhmsg)))
goto enomem;
struct nhmsg *nhm = nlmsg_reserve_object(ns, struct nhmsg);
nhm->nh_family = AF_UNSPEC;
nhm->nh_scope = 0;
nhm->nh_protocol = unhop->un_protocol;
nhm->nh_flags = 0;
nlattr_add_u32(ns, NHA_ID, unhop->un_idx);
nlattr_add_u16(ns, NHA_GROUP_TYPE, NEXTHOP_GRP_TYPE_MPATH);
struct weightened_nhop *wn = unhop->un_nhgrp_src;
uint32_t num_nhops = unhop->un_nhgrp_count;
/* TODO: a better API? */
int nla_len = sizeof(struct nlattr);
nla_len += NETLINK_ALIGN(num_nhops * sizeof(struct nexthop_grp));
struct nlattr *nla = nlmsg_reserve_data(ns, nla_len, struct nlattr);
if (nla == NULL)
goto enomem;
nla->nla_type = NHA_GROUP;
nla->nla_len = nla_len;
for (int i = 0; i < num_nhops; i++) {
struct nexthop_grp *grp = &((struct nexthop_grp *)(nla + 1))[i];
grp->id = nhop_get_uidx(wn[i].nh);
grp->weight = wn[i].weight;
grp->resvd1 = 0;
grp->resvd2 = 0;
}
if (nlmsg_end(ns))
return (true);
enomem:
NL_LOG(LOG_DEBUG, "error: unable to allocate attribute memory");
nlmsg_abort(ns);
return (false);
}
static bool
dump_nhop(const struct user_nhop *unhop, struct nlmsghdr *hdr,
struct nlmsg_state *ns)
{
struct nhop_object *nh = unhop->un_nhop_src;
if (!nlmsg_reply(ns, hdr, sizeof(struct nhmsg)))
goto enomem;
struct nhmsg *nhm = nlmsg_reserve_object(ns, struct nhmsg);
ENOMEM_IF_NULL(nhm);
nhm->nh_family = nhop_get_neigh_family(nh);
nhm->nh_scope = 0; // XXX: what's that?
nhm->nh_protocol = unhop->un_protocol;
nhm->nh_flags = 0;
nlattr_add_u32(ns, NHA_ID, unhop->un_idx);
if (nh->nh_flags & NHF_BLACKHOLE) {
nlattr_add_flag(ns, NHA_BLACKHOLE);
goto done;
}
nlattr_add_u32(ns, NHA_OIF, nh->nh_ifp->if_index);
switch (nh->gw_sa.sa_family) {
#ifdef INET
case AF_INET:
nlattr_add(ns, NHA_GATEWAY, 4, &nh->gw4_sa.sin_addr);
break;
#endif
#ifdef INET6
case AF_INET6:
{
struct in6_addr addr = nh->gw6_sa.sin6_addr;
in6_clearscope(&addr);
nlattr_add(ns, NHA_GATEWAY, 16, &addr);
break;
}
#endif
}
done:
if (nlmsg_end(ns))
return (true);
enomem:
nlmsg_abort(ns);
return (false);
}
static void
dump_unhop(const struct user_nhop *unhop, struct nlmsghdr *hdr,
struct nlmsg_state *ns)
{
if (unhop->un_nhop_src != NULL)
dump_nhop(unhop, hdr, ns);
else
dump_nhgrp(unhop, hdr, ns);
}
static int
delete_unhop(struct unhop_ctl *ctl, struct nlmsghdr *hdr, uint32_t uidx)
{
struct user_nhop *unhop_ret, *unhop_base, *unhop_chain;
struct user_nhop key = { .un_idx = uidx };
UN_WLOCK(ctl);
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop_base);
if (unhop_base != NULL) {
CHT_SLIST_REMOVE(&ctl->un_head, unhop, unhop_base, unhop_ret);
IF_DEBUG_LEVEL(LOG_DEBUG2) {
char nhbuf[NHOP_PRINT_BUFSIZE];
nhop_print_buf_any(unhop_base->un_nhop, nhbuf, sizeof(nhbuf));
FIB_NH_LOG(LOG_DEBUG3, unhop_base->un_nhop,
"removed base nhop %u: %s", uidx, nhbuf);
}
/* Unlink all child nexhops as well, keeping the chain intact */
unhop_chain = unhop_base->un_nextchild;
while (unhop_chain != NULL) {
CHT_SLIST_REMOVE(&ctl->un_head, unhop, unhop_chain,
unhop_ret);
MPASS(unhop_chain == unhop_ret);
IF_DEBUG_LEVEL(LOG_DEBUG3) {
char nhbuf[NHOP_PRINT_BUFSIZE];
nhop_print_buf_any(unhop_chain->un_nhop,
nhbuf, sizeof(nhbuf));
FIB_NH_LOG(LOG_DEBUG3, unhop_chain->un_nhop,
"removed child nhop %u: %s", uidx, nhbuf);
}
unhop_chain = unhop_chain->un_nextchild;
}
}
UN_WUNLOCK(ctl);
if (unhop_base == NULL) {
NL_LOG(LOG_DEBUG, "unable to find unhop %u", uidx);
return (ENOENT);
}
/* Report nexthop deletion */
struct netlink_walkargs wa = {
.hdr.nlmsg_pid = hdr->nlmsg_pid,
.hdr.nlmsg_seq = hdr->nlmsg_seq,
.hdr.nlmsg_flags = hdr->nlmsg_flags,
.hdr.nlmsg_type = NL_RTM_DELNEXTHOP,
};
struct nlmsg_state ns = {};
if (!nlmsg_get_group_writer(NLMSG_SMALL, NETLINK_ROUTE, RTNLGRP_NEXTHOP, &ns)) {
NL_LOG(LOG_DEBUG, "error allocating message writer");
return (ENOMEM);
}
dump_unhop(unhop_base, &wa.hdr, &ns);
nlmsg_flush(&ns);
while (unhop_base != NULL) {
unhop_chain = unhop_base->un_nextchild;
epoch_call(net_epoch_preempt, destroy_unhop_epoch,
&unhop_base->un_epoch_ctx);
unhop_base = unhop_chain;
}
return (0);
}
static void
consider_resize(struct unhop_ctl *ctl, uint32_t new_size)
{
void *new_ptr = NULL;
size_t alloc_size;
if (new_size == 0)
return;
if (new_size != 0) {
alloc_size = CHT_SLIST_GET_RESIZE_SIZE(new_size);
new_ptr = malloc(alloc_size, M_NETLINK, M_NOWAIT | M_ZERO);
if (new_ptr == NULL)
return;
}
NL_LOG(LOG_DEBUG, "resizing hash: %u -> %u", ctl->un_head.hash_size, new_size);
UN_WLOCK(ctl);
if (new_ptr != NULL) {
CHT_SLIST_RESIZE(&ctl->un_head, unhop, new_ptr, new_size);
}
UN_WUNLOCK(ctl);
if (new_ptr != NULL)
free(new_ptr, M_NETLINK);
}
static bool __noinline
vnet_init_unhops()
{
uint32_t num_buckets = 16;
size_t alloc_size = CHT_SLIST_GET_RESIZE_SIZE(num_buckets);
struct unhop_ctl *ctl = malloc(sizeof(struct unhop_ctl), M_NETLINK,
M_NOWAIT | M_ZERO);
if (ctl == NULL)
return (false);
void *ptr = malloc(alloc_size, M_NETLINK, M_NOWAIT | M_ZERO);
if (ptr == NULL) {
free(ctl, M_NETLINK);
return (false);
}
CHT_SLIST_INIT(&ctl->un_head, ptr, num_buckets);
UN_LOCK_INIT(ctl);
if (!atomic_cmpset_ptr((uintptr_t *)&V_un_ctl, (uintptr_t)NULL, (uintptr_t)ctl)) {
free(ptr, M_NETLINK);
free(ctl, M_NETLINK);
}
if (atomic_load_ptr(&V_un_ctl) == NULL)
return (false);
NL_LOG(LOG_NOTICE, "UNHOPS init done");
return (true);
}
static void
vnet_destroy_unhops(const void *unused __unused)
{
struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
struct user_nhop *unhop, *tmp;
if (ctl == NULL)
return;
V_un_ctl = NULL;
/* Wait till all unhop users finish their reads */
epoch_wait_preempt(net_epoch_preempt);
UN_WLOCK(ctl);
CHT_SLIST_FOREACH_SAFE(&ctl->un_head, unhop, unhop, tmp) {
destroy_unhop(unhop);
} CHT_SLIST_FOREACH_SAFE_END;
UN_WUNLOCK(ctl);
free(ctl->un_head.ptr, M_NETLINK);
free(ctl, M_NETLINK);
}
VNET_SYSUNINIT(vnet_destroy_unhops, SI_SUB_PROTO_IF, SI_ORDER_ANY,
vnet_destroy_unhops, NULL);
static int
nlattr_get_nhg(struct nlattr *nla, struct netlink_parse_tracker *npt, void *target)
{
int error = 0;
/* Verify attribute correctness */
struct nexthop_grp *grp = NLA_DATA(nla);
int data_len = NLA_DATA_LEN(nla);
int count = data_len / sizeof(*grp);
if (count == 0 || (count * sizeof(*grp) != data_len)) {
NL_LOG(LOG_DEBUG, "Invalid length for RTA_GROUP: %d", data_len);
return (EINVAL);
}
*((struct nlattr **)target) = nla;
return (error);
}
struct nl_parsed_nhop {
uint32_t nha_id;
uint8_t nha_blackhole;
uint8_t nha_groups;
struct ifnet *nha_oif;
struct sockaddr *nha_gw;
struct nlattr *nha_group;
int nh_family;
};
#define _OFF_S(_field) offsetof(struct nl_parsed_nhop, _field)
static struct nlattr_parser ps[] = {
{ .type = NHA_ID, .off = _OFF_S(nha_id), .cb = nlattr_get_uint32 },
{ .type = NHA_GROUP, .off = _OFF_S(nha_group), .cb = nlattr_get_nhg },
{ .type = NHA_BLACKHOLE, .off = _OFF_S(nha_blackhole), .cb = nlattr_get_flag },
{ .type = NHA_OIF, .off = _OFF_S(nha_oif), .cb = nlattr_get_ifp },
{ .type = NHA_GATEWAY, .off = _OFF_S(nha_gw), .cb = nlattr_get_ip },
{ .type = NHA_GROUPS, .off = _OFF_S(nha_groups), .cb = nlattr_get_flag },
};
static bool
eligible_nhg(const struct nhop_object *nh)
{
return (nh->nh_flags & NHF_GATEWAY);
}
static int
newnhg(struct unhop_ctl *ctl, struct nl_parsed_nhop *attrs, struct user_nhop *unhop)
{
struct nexthop_grp *grp = NLA_DATA(attrs->nha_group);
int count = NLA_DATA_LEN(attrs->nha_group) / sizeof(*grp);
struct weightened_nhop *wn;
wn = malloc(sizeof(*wn) * count, M_NETLINK, M_NOWAIT | M_ZERO);
if (wn == NULL)
return (ENOMEM);
for (int i = 0; i < count; i++) {
struct user_nhop *unhop;
unhop = nl_find_base_unhop(ctl, grp[i].id);
if (unhop == NULL) {
NL_LOG(LOG_DEBUG, "unable to find uidx %u", grp[i].id);
free(wn, M_NETLINK);
return (ESRCH);
} else if (unhop->un_nhop_src == NULL) {
NL_LOG(LOG_DEBUG, "uidx %u is a group, nested group unsupported",
grp[i].id);
free(wn, M_NETLINK);
return (ENOTSUP);
} else if (!eligible_nhg(unhop->un_nhop_src)) {
NL_LOG(LOG_DEBUG, "uidx %u nhop is not mpath-eligible",
grp[i].id);
free(wn, M_NETLINK);
return (ENOTSUP);
}
/*
* TODO: consider more rigid eligibility checks:
* restrict nexthops with the same gateway
*/
wn[i].nh = unhop->un_nhop_src;
wn[i].weight = grp[i].weight;
}
unhop->un_nhgrp_src = wn;
unhop->un_nhgrp_count = count;
return (0);
}
static int
newnhop(struct nl_parsed_nhop *attrs, struct user_nhop *unhop)
{
struct ifaddr *ifa = NULL;
struct nhop_object *nh;
int error;
if (!attrs->nha_blackhole) {
if (attrs->nha_gw == NULL) {
NL_LOG(LOG_DEBUG, "missing NHA_GATEWAY");
return (EINVAL);
}
if (attrs->nha_oif == NULL) {
NL_LOG(LOG_DEBUG, "missing NHA_OIF");
return (EINVAL);
}
if (ifa == NULL)
ifa = ifaof_ifpforaddr(attrs->nha_gw, attrs->nha_oif);
if (ifa == NULL) {
NL_LOG(LOG_DEBUG, "Unable to determine default source IP");
return (EINVAL);
}
}
int family = attrs->nha_gw != NULL ? attrs->nha_gw->sa_family : attrs->nh_family;
nh = nhop_alloc(RT_DEFAULT_FIB, family);
if (nh == NULL) {
NL_LOG(LOG_DEBUG, "Unable to allocate nexthop");
return (ENOMEM);
}
nhop_set_uidx(nh, attrs->nha_id);
if (attrs->nha_blackhole)
nhop_set_blackhole(nh, NHF_BLACKHOLE);
else {
nhop_set_gw(nh, attrs->nha_gw, true);
nhop_set_transmit_ifp(nh, attrs->nha_oif);
nhop_set_src(nh, ifa);
}
error = nhop_get_unlinked(nh);
if (error != 0) {
NL_LOG(LOG_DEBUG, "unable to finalize nexthop");
return (error);
}
IF_DEBUG_LEVEL(LOG_DEBUG2) {
char nhbuf[NHOP_PRINT_BUFSIZE];
nhop_print_buf(nh, nhbuf, sizeof(nhbuf));
NL_LOG(LOG_DEBUG2, "Adding unhop %u: %s", attrs->nha_id, nhbuf);
}
unhop->un_nhop_src = nh;
return (0);
}
static int
rtnl_handle_newnhop(struct nlmsghdr *hdr, struct nlpcb *nlp,
struct netlink_parse_tracker *npt)
{
struct user_nhop *unhop;
int error;
error = nlp_has_priv_route(nlp);
if (error != 0)
return (error);
if ((__predict_false(V_un_ctl == NULL)) && (!vnet_init_unhops()))
return (ENOMEM);
struct unhop_ctl *ctl = V_un_ctl;
struct nhmsg *nhm = (struct nhmsg *)nlmsg_data(hdr);
struct nl_parsed_nhop attrs = { .nh_family = nhm->nh_family };
error = nl_parse_attrs(hdr, sizeof(*nhm), ps, sizeof(ps)/sizeof(ps[0]), npt, &attrs);
if (error != 0)
return (error);
/*
* Get valid nha_id. Treat nha_id == 0 (auto-assignment) as a second-class
* citizen.
*/
if (attrs.nha_id == 0) {
attrs.nha_id = find_spare_uidx(ctl);
if (attrs.nha_id == 0) {
NL_LOG(LOG_DEBUG, "Unable to get spare uidx");
return (ENOSPC);
}
}
NL_LOG(LOG_DEBUG, "IFINDEX %d", attrs.nha_oif ? attrs.nha_oif->if_index : 0);
unhop = malloc(sizeof(struct user_nhop), M_NETLINK, M_NOWAIT | M_ZERO);
if (unhop == NULL) {
NL_LOG(LOG_DEBUG, "Unable to allocate user_nhop");
return (ENOMEM);
}
unhop->un_idx = attrs.nha_id;
unhop->un_protocol = nhm->nh_protocol;
if (attrs.nha_group)
error = newnhg(ctl, &attrs, unhop);
else
error = newnhop(&attrs, unhop);
if (error != 0) {
free(unhop, M_NETLINK);
return (error);
}
UN_WLOCK(ctl);
/* Check if uidx already exists */
struct user_nhop *tmp = NULL;
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, unhop, tmp);
if (tmp != NULL) {
UN_WUNLOCK(ctl);
NL_LOG(LOG_DEBUG, "nhop idx %u already exists", attrs.nha_id);
destroy_unhop(unhop);
return (EEXIST);
}
CHT_SLIST_INSERT_HEAD(&ctl->un_head, unhop, unhop);
uint32_t num_buckets_new = CHT_SLIST_GET_RESIZE_BUCKETS(&ctl->un_head);
UN_WUNLOCK(ctl);
/* Report addition of the next nexhop */
struct netlink_walkargs wa = {
.hdr.nlmsg_pid = hdr->nlmsg_pid,
.hdr.nlmsg_seq = hdr->nlmsg_seq,
.hdr.nlmsg_flags = hdr->nlmsg_flags,
.hdr.nlmsg_type = NL_RTM_NEWNEXTHOP,
};
struct nlmsg_state ns = {};
if (!nlmsg_get_group_writer(NLMSG_SMALL, NETLINK_ROUTE, RTNLGRP_NEXTHOP, &ns)) {
NL_LOG(LOG_DEBUG, "error allocating message writer");
return (ENOMEM);
}
dump_unhop(unhop, &wa.hdr, &ns);
nlmsg_flush(&ns);
consider_resize(ctl, num_buckets_new);
return (0);
}
static int
rtnl_handle_delnhop(struct nlmsghdr *hdr, struct nlpcb *nlp,
struct netlink_parse_tracker *npt)
{
struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
int error;
error = nlp_has_priv_route(nlp);
if (error != 0)
return (error);
if (__predict_false(ctl == NULL))
return (ESRCH);
struct nhmsg *nhm = (struct nhmsg *)nlmsg_data(hdr);
struct nl_parsed_nhop attrs = {};
error = nl_parse_attrs(hdr, sizeof(*nhm), ps, sizeof(ps)/sizeof(ps[0]), npt, &attrs);
if (error != 0)
return (error);
if (attrs.nha_id == 0) {
NL_LOG(LOG_DEBUG, "NHA_ID not set");
return (EINVAL);
}
error = delete_unhop(ctl, hdr, attrs.nha_id);
return (error);
}
static bool
match_unhop(const struct nl_parsed_nhop *attrs, struct user_nhop *unhop)
{
if (attrs->nha_id != 0 && unhop->un_idx != attrs->nha_id)
return (false);
if (attrs->nha_groups != 0 && unhop->un_nhgrp_src == NULL)
return (false);
if (attrs->nha_oif != NULL &&
(unhop->un_nhop_src == NULL || unhop->un_nhop_src->nh_ifp != attrs->nha_oif))
return (false);
return (true);
}
static int
rtnl_handle_getnhop(struct nlmsghdr *hdr, struct nlpcb *nlp,
struct netlink_parse_tracker *npt)
{
struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
struct user_nhop *unhop;
UN_TRACKER;
int error;
if (__predict_false(ctl == NULL))
return (ESRCH);
struct nhmsg *nhm = (struct nhmsg *)nlmsg_data(hdr);
struct nl_parsed_nhop attrs = {};
error = nl_parse_attrs(hdr, sizeof(*nhm), ps, sizeof(ps)/sizeof(ps[0]), npt, &attrs);
if (error != 0)
return (error);
struct netlink_walkargs wa = {
.ns = npt->ns,
.hdr.nlmsg_pid = hdr->nlmsg_pid,
.hdr.nlmsg_seq = hdr->nlmsg_seq,
.hdr.nlmsg_flags = hdr->nlmsg_flags,
.hdr.nlmsg_type = NL_RTM_NEWNEXTHOP,
};
if (attrs.nha_id != 0) {
NL_LOG(LOG_DEBUG2, "searching for uidx %u", attrs.nha_id);
struct user_nhop key= { .un_idx = attrs.nha_id };
UN_RLOCK(ctl);
CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
UN_RUNLOCK(ctl);
if (unhop == NULL)
return (ESRCH);
dump_unhop(unhop, &wa.hdr, wa.ns);
return (0);
}
UN_RLOCK(ctl);
wa.hdr.nlmsg_flags |= NLM_F_MULTI;
CHT_SLIST_FOREACH(&ctl->un_head, unhop, unhop) {
if (UNHOP_IS_MASTER(unhop) && match_unhop(&attrs, unhop))
dump_unhop(unhop, &wa.hdr, wa.ns);
} CHT_SLIST_FOREACH_END;
UN_RUNLOCK(ctl);
if (wa.error == 0) {
if (!nlmsg_end_dump(wa.ns, wa.error, &wa.hdr))
return (ENOMEM);
}
return (0);
}
static struct rtnl_cmd_handler cmd_handlers[] = {
{ NL_RTM_GETNEXTHOP, "RTM_GETNEXTHOP", &rtnl_handle_getnhop, sizeof(struct nhmsg)},
{ NL_RTM_DELNEXTHOP, "RTM_DELNEXTHOP", &rtnl_handle_delnhop, sizeof(struct nhmsg)},
{ NL_RTM_NEWNEXTHOP, "RTM_NEWNEXTHOP", &rtnl_handle_newnhop, sizeof(struct nhmsg)},
};
void
rtnl_nexthops_init()
{
rtnl_register_messages(cmd_handlers, NL_ARRAY_LEN(cmd_handlers));
}