--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Generic nexthop implementation
+ *
+ * Copyright (c) 2017-19 Cumulus Networks
+ * Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
+ */
+
+#include <linux/nexthop.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+#include <net/nexthop.h>
+#include <net/sock.h>
+
+static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = {
+ [NHA_UNSPEC] = { .strict_start_type = NHA_UNSPEC + 1 },
+ [NHA_ID] = { .type = NLA_U32 },
+ [NHA_GROUP] = { .type = NLA_BINARY },
+ [NHA_GROUP_TYPE] = { .type = NLA_U16 },
+ [NHA_BLACKHOLE] = { .type = NLA_FLAG },
+ [NHA_OIF] = { .type = NLA_U32 },
+ [NHA_GATEWAY] = { .type = NLA_BINARY },
+ [NHA_ENCAP_TYPE] = { .type = NLA_U16 },
+ [NHA_ENCAP] = { .type = NLA_NESTED },
+ [NHA_GROUPS] = { .type = NLA_FLAG },
+ [NHA_MASTER] = { .type = NLA_U32 },
+};
+
+void nexthop_free_rcu(struct rcu_head *head)
+{
+ struct nexthop *nh = container_of(head, struct nexthop, rcu);
+ struct nh_info *nhi;
+
+ nhi = rcu_dereference_raw(nh->nh_info);
+ kfree(nhi);
+
+ kfree(nh);
+}
+EXPORT_SYMBOL_GPL(nexthop_free_rcu);
+
+static struct nexthop *nexthop_alloc(void)
+{
+ struct nexthop *nh;
+
+ nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);
+ return nh;
+}
+
+static void nh_base_seq_inc(struct net *net)
+{
+ while (++net->nexthop.seq == 0)
+ ;
+}
+
+/* no reference taken; rcu lock or rtnl must be held */
+struct nexthop *nexthop_find_by_id(struct net *net, u32 id)
+{
+ struct rb_node **pp, *parent = NULL, *next;
+
+ pp = &net->nexthop.rb_root.rb_node;
+ while (1) {
+ struct nexthop *nh;
+
+ next = rcu_dereference_raw(*pp);
+ if (!next)
+ break;
+ parent = next;
+
+ nh = rb_entry(parent, struct nexthop, rb_node);
+ if (id < nh->id)
+ pp = &next->rb_left;
+ else if (id > nh->id)
+ pp = &next->rb_right;
+ else
+ return nh;
+ }
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(nexthop_find_by_id);
+
+/* used for auto id allocation; called with rtnl held */
+static u32 nh_find_unused_id(struct net *net)
+{
+ u32 id_start = net->nexthop.last_id_allocated;
+
+ while (1) {
+ net->nexthop.last_id_allocated++;
+ if (net->nexthop.last_id_allocated == id_start)
+ break;
+
+ if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated))
+ return net->nexthop.last_id_allocated;
+ }
+ return 0;
+}
+
+static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
+ int event, u32 portid, u32 seq, unsigned int nlflags)
+{
+ struct nlmsghdr *nlh;
+ struct nh_info *nhi;
+ struct nhmsg *nhm;
+
+ nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
+ if (!nlh)
+ return -EMSGSIZE;
+
+ nhm = nlmsg_data(nlh);
+ nhm->nh_family = AF_UNSPEC;
+ nhm->nh_flags = nh->nh_flags;
+ nhm->nh_protocol = nh->protocol;
+ nhm->nh_scope = 0;
+ nhm->resvd = 0;
+
+ if (nla_put_u32(skb, NHA_ID, nh->id))
+ goto nla_put_failure;
+
+ nhi = rtnl_dereference(nh->nh_info);
+ nhm->nh_family = nhi->family;
+ if (nhi->reject_nh) {
+ if (nla_put_flag(skb, NHA_BLACKHOLE))
+ goto nla_put_failure;
+ goto out;
+ }
+
+out:
+ nlmsg_end(skb, nlh);
+ return 0;
+
+nla_put_failure:
+ return -EMSGSIZE;
+}
+
+static size_t nh_nlmsg_size(struct nexthop *nh)
+{
+ size_t sz = nla_total_size(4); /* NHA_ID */
+
+ /* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE
+ * are mutually exclusive
+ */
+ sz += nla_total_size(4); /* NHA_OIF */
+
+ return sz;
+}
+
+static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info)
+{
+ unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0;
+ u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
+ struct sk_buff *skb;
+ int err = -ENOBUFS;
+
+ skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any());
+ if (!skb)
+ goto errout;
+
+ err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags);
+ if (err < 0) {
+ /* -EMSGSIZE implies BUG in nh_nlmsg_size() */
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(skb);
+ goto errout;
+ }
+
+ rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP,
+ info->nlh, gfp_any());
+ return;
+errout:
+ if (err < 0)
+ rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err);
+}
+
+static void remove_nexthop(struct net *net, struct nexthop *nh,
+ bool skip_fib, struct nl_info *nlinfo)
+{
+ /* remove from the tree */
+ rb_erase(&nh->rb_node, &net->nexthop.rb_root);
+
+ if (nlinfo)
+ nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo);
+
+ nh_base_seq_inc(net);
+
+ nexthop_put(nh);
+}
+
+static int replace_nexthop(struct net *net, struct nexthop *old,
+ struct nexthop *new, struct netlink_ext_ack *extack)
+{
+ return -EEXIST;
+}
+
+/* called with rtnl_lock held */
+static int insert_nexthop(struct net *net, struct nexthop *new_nh,
+ struct nh_config *cfg, struct netlink_ext_ack *extack)
+{
+ struct rb_node **pp, *parent = NULL, *next;
+ struct rb_root *root = &net->nexthop.rb_root;
+ bool replace = !!(cfg->nlflags & NLM_F_REPLACE);
+ bool create = !!(cfg->nlflags & NLM_F_CREATE);
+ u32 new_id = new_nh->id;
+ int rc = -EEXIST;
+
+ pp = &root->rb_node;
+ while (1) {
+ struct nexthop *nh;
+
+ next = rtnl_dereference(*pp);
+ if (!next)
+ break;
+
+ parent = next;
+
+ nh = rb_entry(parent, struct nexthop, rb_node);
+ if (new_id < nh->id) {
+ pp = &next->rb_left;
+ } else if (new_id > nh->id) {
+ pp = &next->rb_right;
+ } else if (replace) {
+ rc = replace_nexthop(net, nh, new_nh, extack);
+ if (!rc)
+ new_nh = nh; /* send notification with old nh */
+ goto out;
+ } else {
+ /* id already exists and not a replace */
+ goto out;
+ }
+ }
+
+ if (replace && !create) {
+ NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists");
+ rc = -ENOENT;
+ goto out;
+ }
+
+ rb_link_node_rcu(&new_nh->rb_node, parent, pp);
+ rb_insert_color(&new_nh->rb_node, root);
+ rc = 0;
+out:
+ if (!rc) {
+ nh_base_seq_inc(net);
+ nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
+ }
+
+ return rc;
+}
+
+/* rtnl; called when net namespace is deleted */
+static void flush_all_nexthops(struct net *net)
+{
+ struct rb_root *root = &net->nexthop.rb_root;
+ struct rb_node *node;
+ struct nexthop *nh;
+
+ while ((node = rb_first(root))) {
+ nh = rb_entry(node, struct nexthop, rb_node);
+ remove_nexthop(net, nh, false, NULL);
+ cond_resched();
+ }
+}
+
+static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg,
+ struct netlink_ext_ack *extack)
+{
+ struct nh_info *nhi;
+ struct nexthop *nh;
+ int err = 0;
+
+ nh = nexthop_alloc();
+ if (!nh)
+ return ERR_PTR(-ENOMEM);
+
+ nhi = kzalloc(sizeof(*nhi), GFP_KERNEL);
+ if (!nhi) {
+ kfree(nh);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ nh->nh_flags = cfg->nh_flags;
+ nh->net = net;
+
+ nhi->nh_parent = nh;
+ nhi->family = cfg->nh_family;
+ nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK;
+
+ if (cfg->nh_blackhole) {
+ nhi->reject_nh = 1;
+ cfg->nh_ifindex = net->loopback_dev->ifindex;
+ }
+
+ if (err) {
+ kfree(nhi);
+ kfree(nh);
+ return ERR_PTR(err);
+ }
+
+ rcu_assign_pointer(nh->nh_info, nhi);
+
+ return nh;
+}
+
+/* called with rtnl lock held */
+static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg,
+ struct netlink_ext_ack *extack)
+{
+ struct nexthop *nh;
+ int err;
+
+ if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) {
+ NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
+ return ERR_PTR(-EINVAL);
+ }
+
+ if (!cfg->nh_id) {
+ cfg->nh_id = nh_find_unused_id(net);
+ if (!cfg->nh_id) {
+ NL_SET_ERR_MSG(extack, "No unused id");
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
+ nh = nexthop_create(net, cfg, extack);
+ if (IS_ERR(nh))
+ return nh;
+
+ refcount_set(&nh->refcnt, 1);
+ nh->id = cfg->nh_id;
+ nh->protocol = cfg->nh_protocol;
+ nh->net = net;
+
+ err = insert_nexthop(net, nh, cfg, extack);
+ if (err) {
+ nexthop_put(nh);
+ nh = ERR_PTR(err);
+ }
+
+ return nh;
+}
+
+static int rtm_to_nh_config(struct net *net, struct sk_buff *skb,
+ struct nlmsghdr *nlh, struct nh_config *cfg,
+ struct netlink_ext_ack *extack)
+{
+ struct nhmsg *nhm = nlmsg_data(nlh);
+ struct nlattr *tb[NHA_MAX + 1];
+ int err;
+
+ err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
+ extack);
+ if (err < 0)
+ return err;
+
+ err = -EINVAL;
+ if (nhm->resvd || nhm->nh_scope) {
+ NL_SET_ERR_MSG(extack, "Invalid values in ancillary header");
+ goto out;
+ }
+ if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) {
+ NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header");
+ goto out;
+ }
+
+ switch (nhm->nh_family) {
+ default:
+ NL_SET_ERR_MSG(extack, "Invalid address family");
+ goto out;
+ }
+
+ if (tb[NHA_GROUPS] || tb[NHA_MASTER]) {
+ NL_SET_ERR_MSG(extack, "Invalid attributes in request");
+ goto out;
+ }
+
+ memset(cfg, 0, sizeof(*cfg));
+ cfg->nlflags = nlh->nlmsg_flags;
+ cfg->nlinfo.portid = NETLINK_CB(skb).portid;
+ cfg->nlinfo.nlh = nlh;
+ cfg->nlinfo.nl_net = net;
+
+ cfg->nh_family = nhm->nh_family;
+ cfg->nh_protocol = nhm->nh_protocol;
+ cfg->nh_flags = nhm->nh_flags;
+
+ if (tb[NHA_ID])
+ cfg->nh_id = nla_get_u32(tb[NHA_ID]);
+
+ if (tb[NHA_BLACKHOLE]) {
+ if (tb[NHA_GATEWAY] || tb[NHA_OIF]) {
+ NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway or oif");
+ goto out;
+ }
+
+ cfg->nh_blackhole = 1;
+ err = 0;
+ goto out;
+ }
+
+ if (!tb[NHA_OIF]) {
+ NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole nexthops");
+ goto out;
+ }
+
+ cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]);
+ if (cfg->nh_ifindex)
+ cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex);
+
+ if (!cfg->dev) {
+ NL_SET_ERR_MSG(extack, "Invalid device index");
+ goto out;
+ } else if (!(cfg->dev->flags & IFF_UP)) {
+ NL_SET_ERR_MSG(extack, "Nexthop device is not up");
+ err = -ENETDOWN;
+ goto out;
+ } else if (!netif_carrier_ok(cfg->dev)) {
+ NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down");
+ err = -ENETDOWN;
+ goto out;
+ }
+
+ err = 0;
+out:
+ return err;
+}
+
+/* rtnl */
+static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(skb->sk);
+ struct nh_config cfg;
+ struct nexthop *nh;
+ int err;
+
+ err = rtm_to_nh_config(net, skb, nlh, &cfg, extack);
+ if (!err) {
+ nh = nexthop_add(net, &cfg, extack);
+ if (IS_ERR(nh))
+ err = PTR_ERR(nh);
+ }
+
+ return err;
+}
+
+static int nh_valid_get_del_req(struct nlmsghdr *nlh, u32 *id,
+ struct netlink_ext_ack *extack)
+{
+ struct nhmsg *nhm = nlmsg_data(nlh);
+ struct nlattr *tb[NHA_MAX + 1];
+ int err, i;
+
+ err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
+ extack);
+ if (err < 0)
+ return err;
+
+ err = -EINVAL;
+ for (i = 0; i < __NHA_MAX; ++i) {
+ if (!tb[i])
+ continue;
+
+ switch (i) {
+ case NHA_ID:
+ break;
+ default:
+ NL_SET_ERR_MSG_ATTR(extack, tb[i],
+ "Unexpected attribute in request");
+ goto out;
+ }
+ }
+ if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
+ NL_SET_ERR_MSG(extack, "Invalid values in header");
+ goto out;
+ }
+
+ if (!tb[NHA_ID]) {
+ NL_SET_ERR_MSG(extack, "Nexthop id is missing");
+ goto out;
+ }
+
+ *id = nla_get_u32(tb[NHA_ID]);
+ if (!(*id))
+ NL_SET_ERR_MSG(extack, "Invalid nexthop id");
+ else
+ err = 0;
+out:
+ return err;
+}
+
+/* rtnl */
+static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(skb->sk);
+ struct nl_info nlinfo = {
+ .nlh = nlh,
+ .nl_net = net,
+ .portid = NETLINK_CB(skb).portid,
+ };
+ struct nexthop *nh;
+ int err;
+ u32 id;
+
+ err = nh_valid_get_del_req(nlh, &id, extack);
+ if (err)
+ return err;
+
+ nh = nexthop_find_by_id(net, id);
+ if (!nh)
+ return -ENOENT;
+
+ remove_nexthop(net, nh, false, &nlinfo);
+
+ return 0;
+}
+
+/* rtnl */
+static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(in_skb->sk);
+ struct sk_buff *skb = NULL;
+ struct nexthop *nh;
+ int err;
+ u32 id;
+
+ err = nh_valid_get_del_req(nlh, &id, extack);
+ if (err)
+ return err;
+
+ err = -ENOBUFS;
+ skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
+ if (!skb)
+ goto out;
+
+ err = -ENOENT;
+ nh = nexthop_find_by_id(net, id);
+ if (!nh)
+ goto errout_free;
+
+ err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid,
+ nlh->nlmsg_seq, 0);
+ if (err < 0) {
+ WARN_ON(err == -EMSGSIZE);
+ goto errout_free;
+ }
+
+ err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
+out:
+ return err;
+errout_free:
+ kfree_skb(skb);
+ goto out;
+}
+
+static bool nh_dump_filtered(struct nexthop *nh, int dev_idx,
+ int master_idx, u8 family)
+{
+ const struct net_device *dev;
+ const struct nh_info *nhi;
+
+ if (!dev_idx && !master_idx && !family)
+ return false;
+
+ nhi = rtnl_dereference(nh->nh_info);
+ if (family && nhi->family != family)
+ return true;
+
+ dev = nhi->fib_nhc.nhc_dev;
+ if (dev_idx && (!dev || dev->ifindex != dev_idx))
+ return true;
+
+ if (master_idx) {
+ struct net_device *master;
+
+ if (!dev)
+ return true;
+
+ master = netdev_master_upper_dev_get((struct net_device *)dev);
+ if (!master || master->ifindex != master_idx)
+ return true;
+ }
+
+ return false;
+}
+
+static int nh_valid_dump_req(const struct nlmsghdr *nlh,
+ int *dev_idx, int *master_idx,
+ struct netlink_callback *cb)
+{
+ struct netlink_ext_ack *extack = cb->extack;
+ struct nlattr *tb[NHA_MAX + 1];
+ struct nhmsg *nhm;
+ int err, i;
+ u32 idx;
+
+ err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
+ NULL);
+ if (err < 0)
+ return err;
+
+ for (i = 0; i <= NHA_MAX; ++i) {
+ if (!tb[i])
+ continue;
+
+ switch (i) {
+ case NHA_OIF:
+ idx = nla_get_u32(tb[i]);
+ if (idx > INT_MAX) {
+ NL_SET_ERR_MSG(extack, "Invalid device index");
+ return -EINVAL;
+ }
+ *dev_idx = idx;
+ break;
+ case NHA_MASTER:
+ idx = nla_get_u32(tb[i]);
+ if (idx > INT_MAX) {
+ NL_SET_ERR_MSG(extack, "Invalid master device index");
+ return -EINVAL;
+ }
+ *master_idx = idx;
+ break;
+ default:
+ NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
+ return -EINVAL;
+ }
+ }
+
+ nhm = nlmsg_data(nlh);
+ if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
+ NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* rtnl */
+static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct nhmsg *nhm = nlmsg_data(cb->nlh);
+ int dev_filter_idx = 0, master_idx = 0;
+ struct net *net = sock_net(skb->sk);
+ struct rb_root *root = &net->nexthop.rb_root;
+ struct rb_node *node;
+ int idx = 0, s_idx;
+ int err;
+
+ err = nh_valid_dump_req(cb->nlh, &dev_filter_idx, &master_idx, cb);
+ if (err < 0)
+ return err;
+
+ s_idx = cb->args[0];
+ for (node = rb_first(root); node; node = rb_next(node)) {
+ struct nexthop *nh;
+
+ if (idx < s_idx)
+ goto cont;
+
+ nh = rb_entry(node, struct nexthop, rb_node);
+ if (nh_dump_filtered(nh, dev_filter_idx, master_idx,
+ nhm->nh_family))
+ goto cont;
+
+ err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP,
+ NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, NLM_F_MULTI);
+ if (err < 0) {
+ if (likely(skb->len))
+ goto out;
+
+ goto out_err;
+ }
+cont:
+ idx++;
+ }
+
+out:
+ err = skb->len;
+out_err:
+ cb->args[0] = idx;
+ cb->seq = net->nexthop.seq;
+ nl_dump_check_consistent(cb, nlmsg_hdr(skb));
+
+ return err;
+}
+
+static void __net_exit nexthop_net_exit(struct net *net)
+{
+ rtnl_lock();
+ flush_all_nexthops(net);
+ rtnl_unlock();
+}
+
+static int __net_init nexthop_net_init(struct net *net)
+{
+ net->nexthop.rb_root = RB_ROOT;
+
+ return 0;
+}
+
+static struct pernet_operations nexthop_net_ops = {
+ .init = nexthop_net_init,
+ .exit = nexthop_net_exit,
+};
+
+static int __init nexthop_init(void)
+{
+ register_pernet_subsys(&nexthop_net_ops);
+
+ rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
+ rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0);
+ rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop,
+ rtm_dump_nexthop, 0);
+
+ rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
+ rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
+
+ rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
+ rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
+
+ return 0;
+}
+subsys_initcall(nexthop_init);
projects / mirror_ubuntu-kernels.git / commitdiff