From 597cfe4fc3390a055f42546c254e48601b37009f Mon Sep 17 00:00:00 2001 From: David Ahern Date: Fri, 24 May 2019 14:43:05 -0700 Subject: [PATCH] nexthop: Add support for IPv4 nexthops Add support for IPv4 nexthops. If nh_family is set to AF_INET, then NHA_GATEWAY is expected to be an IPv4 address. Register for netdev events to be notified of admin up/down changes as well as deletes. A hash table is used to track nexthop per devices to quickly convert device events to the affected nexthops. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- include/net/nexthop.h | 5 + net/ipv4/nexthop.c | 208 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 213 insertions(+) diff --git a/include/net/nexthop.h b/include/net/nexthop.h index 18e1f512f866..c0e4b0d92c39 100644 --- a/include/net/nexthop.h +++ b/include/net/nexthop.h @@ -29,6 +29,10 @@ struct nh_config { int nh_ifindex; struct net_device *dev; + union { + __be32 ipv4; + } gw; + u32 nlflags; struct nl_info nlinfo; }; @@ -42,6 +46,7 @@ struct nh_info { union { struct fib_nh_common fib_nhc; + struct fib_nh fib_nh; }; }; diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c index ec0ccf2ed873..79c7b3461e19 100644 --- a/net/ipv4/nexthop.c +++ b/net/ipv4/nexthop.c @@ -9,8 +9,12 @@ #include #include #include +#include #include +#define NH_DEV_HASHBITS 8 +#define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS) + static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = { [NHA_UNSPEC] = { .strict_start_type = NHA_UNSPEC + 1 }, [NHA_ID] = { .type = NLA_U32 }, @@ -25,12 +29,39 @@ static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = { [NHA_MASTER] = { .type = NLA_U32 }, }; +static unsigned int nh_dev_hashfn(unsigned int val) +{ + unsigned int mask = NH_DEV_HASHSIZE - 1; + + return (val ^ + (val >> NH_DEV_HASHBITS) ^ + (val >> (NH_DEV_HASHBITS * 2))) & mask; +} + +static void nexthop_devhash_add(struct net *net, struct nh_info *nhi) +{ + struct net_device *dev = nhi->fib_nhc.nhc_dev; + struct hlist_head *head; + unsigned int hash; + + WARN_ON(!dev); + + hash = nh_dev_hashfn(dev->ifindex); + head = &net->nexthop.devhash[hash]; + hlist_add_head(&nhi->dev_hash, head); +} + 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); + switch (nhi->family) { + case AF_INET: + fib_nh_release(nh->net, &nhi->fib_nh); + break; + } kfree(nhi); kfree(nh); @@ -96,6 +127,7 @@ static u32 nh_find_unused_id(struct net *net) static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh, int event, u32 portid, u32 seq, unsigned int nlflags) { + struct fib_nh *fib_nh; struct nlmsghdr *nlh; struct nh_info *nhi; struct nhmsg *nhm; @@ -120,6 +152,22 @@ static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh, if (nla_put_flag(skb, NHA_BLACKHOLE)) goto nla_put_failure; goto out; + } else { + const struct net_device *dev; + + dev = nhi->fib_nhc.nhc_dev; + if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex)) + goto nla_put_failure; + } + + nhm->nh_scope = nhi->fib_nhc.nhc_scope; + switch (nhi->family) { + case AF_INET: + fib_nh = &nhi->fib_nh; + if (fib_nh->fib_nh_gw_family && + nla_put_u32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4)) + goto nla_put_failure; + break; } out: @@ -132,6 +180,7 @@ static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh, static size_t nh_nlmsg_size(struct nexthop *nh) { + struct nh_info *nhi = rtnl_dereference(nh->nh_info); size_t sz = nla_total_size(4); /* NHA_ID */ /* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE @@ -139,6 +188,13 @@ static size_t nh_nlmsg_size(struct nexthop *nh) */ sz += nla_total_size(4); /* NHA_OIF */ + switch (nhi->family) { + case AF_INET: + if (nhi->fib_nh.fib_nh_gw_family) + sz += nla_total_size(4); /* NHA_GATEWAY */ + break; + } + return sz; } @@ -169,6 +225,15 @@ static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info) rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err); } +static void __remove_nexthop(struct net *net, struct nexthop *nh) +{ + struct nh_info *nhi; + + nhi = rtnl_dereference(nh->nh_info); + if (nhi->fib_nhc.nhc_dev) + hlist_del(&nhi->dev_hash); +} + static void remove_nexthop(struct net *net, struct nexthop *nh, bool skip_fib, struct nl_info *nlinfo) { @@ -178,6 +243,7 @@ static void remove_nexthop(struct net *net, struct nexthop *nh, if (nlinfo) nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo); + __remove_nexthop(net, nh); nh_base_seq_inc(net); nexthop_put(nh); @@ -244,6 +310,24 @@ static int insert_nexthop(struct net *net, struct nexthop *new_nh, return rc; } +/* rtnl */ +/* remove all nexthops tied to a device being deleted */ +static void nexthop_flush_dev(struct net_device *dev) +{ + unsigned int hash = nh_dev_hashfn(dev->ifindex); + struct net *net = dev_net(dev); + struct hlist_head *head = &net->nexthop.devhash[hash]; + struct hlist_node *n; + struct nh_info *nhi; + + hlist_for_each_entry_safe(nhi, n, head, dev_hash) { + if (nhi->fib_nhc.nhc_dev != dev) + continue; + + remove_nexthop(net, nhi->nh_parent, false, NULL); + } +} + /* rtnl; called when net namespace is deleted */ static void flush_all_nexthops(struct net *net) { @@ -258,6 +342,38 @@ static void flush_all_nexthops(struct net *net) } } +static int nh_create_ipv4(struct net *net, struct nexthop *nh, + struct nh_info *nhi, struct nh_config *cfg, + struct netlink_ext_ack *extack) +{ + struct fib_nh *fib_nh = &nhi->fib_nh; + struct fib_config fib_cfg = { + .fc_oif = cfg->nh_ifindex, + .fc_gw4 = cfg->gw.ipv4, + .fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0, + .fc_flags = cfg->nh_flags, + }; + u32 tb_id = l3mdev_fib_table(cfg->dev); + int err = -EINVAL; + + err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack); + if (err) { + fib_nh_release(net, fib_nh); + goto out; + } + + /* sets nh_dev if successful */ + err = fib_check_nh(net, fib_nh, tb_id, 0, extack); + if (!err) { + nh->nh_flags = fib_nh->fib_nh_flags; + fib_info_update_nh_saddr(net, fib_nh, fib_nh->fib_nh_scope); + } else { + fib_nh_release(net, fib_nh); + } +out: + return err; +} + static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg, struct netlink_ext_ack *extack) { @@ -287,12 +403,21 @@ static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg, cfg->nh_ifindex = net->loopback_dev->ifindex; } + switch (cfg->nh_family) { + case AF_INET: + err = nh_create_ipv4(net, nh, nhi, cfg, extack); + break; + } + if (err) { kfree(nhi); kfree(nh); return ERR_PTR(err); } + /* add the entry to the device based hash */ + nexthop_devhash_add(net, nhi); + rcu_assign_pointer(nh->nh_info, nhi); return nh; @@ -329,6 +454,7 @@ static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg, err = insert_nexthop(net, nh, cfg, extack); if (err) { + __remove_nexthop(net, nh); nexthop_put(nh); nh = ERR_PTR(err); } @@ -360,6 +486,8 @@ static int rtm_to_nh_config(struct net *net, struct sk_buff *skb, } switch (nhm->nh_family) { + case AF_INET: + break; default: NL_SET_ERR_MSG(extack, "Invalid address family"); goto out; @@ -416,6 +544,32 @@ static int rtm_to_nh_config(struct net *net, struct sk_buff *skb, goto out; } + err = -EINVAL; + if (tb[NHA_GATEWAY]) { + struct nlattr *gwa = tb[NHA_GATEWAY]; + + switch (cfg->nh_family) { + case AF_INET: + if (nla_len(gwa) != sizeof(u32)) { + NL_SET_ERR_MSG(extack, "Invalid gateway"); + goto out; + } + cfg->gw.ipv4 = nla_get_be32(gwa); + break; + default: + NL_SET_ERR_MSG(extack, + "Unknown address family for gateway"); + goto out; + } + } else { + /* device only nexthop (no gateway) */ + if (cfg->nh_flags & RTNH_F_ONLINK) { + NL_SET_ERR_MSG(extack, + "ONLINK flag can not be set for nexthop without a gateway"); + goto out; + } + } + err = 0; out: return err; @@ -683,16 +837,68 @@ static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb) return err; } +static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu) +{ + unsigned int hash = nh_dev_hashfn(dev->ifindex); + struct net *net = dev_net(dev); + struct hlist_head *head = &net->nexthop.devhash[hash]; + struct hlist_node *n; + struct nh_info *nhi; + + hlist_for_each_entry_safe(nhi, n, head, dev_hash) { + if (nhi->fib_nhc.nhc_dev == dev) { + if (nhi->family == AF_INET) + fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu, + orig_mtu); + } + } +} + +/* rtnl */ +static int nh_netdev_event(struct notifier_block *this, + unsigned long event, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct netdev_notifier_info_ext *info_ext; + + switch (event) { + case NETDEV_DOWN: + case NETDEV_UNREGISTER: + nexthop_flush_dev(dev); + break; + case NETDEV_CHANGE: + if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP))) + nexthop_flush_dev(dev); + break; + case NETDEV_CHANGEMTU: + info_ext = ptr; + nexthop_sync_mtu(dev, info_ext->ext.mtu); + rt_cache_flush(dev_net(dev)); + break; + } + return NOTIFY_DONE; +} + +static struct notifier_block nh_netdev_notifier = { + .notifier_call = nh_netdev_event, +}; + static void __net_exit nexthop_net_exit(struct net *net) { rtnl_lock(); flush_all_nexthops(net); rtnl_unlock(); + kfree(net->nexthop.devhash); } static int __net_init nexthop_net_init(struct net *net) { + size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE; + net->nexthop.rb_root = RB_ROOT; + net->nexthop.devhash = kzalloc(sz, GFP_KERNEL); + if (!net->nexthop.devhash) + return -ENOMEM; return 0; } @@ -706,6 +912,8 @@ static int __init nexthop_init(void) { register_pernet_subsys(&nexthop_net_ops); + register_netdevice_notifier(&nh_netdev_notifier); + 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, -- 2.45.2