diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/Makefile | 2 | ||||
| -rw-r--r-- | net/ipv4/nexthop.c | 722 |
2 files changed, 723 insertions, 1 deletions
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index 000a61994c8f..d57ecfaf89d4 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -14,7 +14,7 @@ obj-y := route.o inetpeer.o protocol.o \ udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \ fib_frontend.o fib_semantics.o fib_trie.o fib_notifier.o \ inet_fragment.o ping.o ip_tunnel_core.o gre_offload.o \ - metrics.o netlink.o + metrics.o netlink.o nexthop.o obj-$(CONFIG_BPFILTER) += bpfilter/ diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c new file mode 100644 index 000000000000..ec0ccf2ed873 --- /dev/null +++ b/net/ipv4/nexthop.c @@ -0,0 +1,722 @@ +// 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); |