--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/* net/sched/act_ctinfo.c  netfilter ctinfo connmark actions
+ *
+ * Copyright (c) 2019 Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/pkt_cls.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/act_api.h>
+#include <net/pkt_cls.h>
+#include <uapi/linux/tc_act/tc_ctinfo.h>
+#include <net/tc_act/tc_ctinfo.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_ecache.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+
+static struct tc_action_ops act_ctinfo_ops;
+static unsigned int ctinfo_net_id;
+
+static void tcf_ctinfo_dscp_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
+                               struct tcf_ctinfo_params *cp,
+                               struct sk_buff *skb, int wlen, int proto)
+{
+       u8 dscp, newdscp;
+
+       newdscp = (((ct->mark & cp->dscpmask) >> cp->dscpmaskshift) << 2) &
+                    ~INET_ECN_MASK;
+
+       switch (proto) {
+       case NFPROTO_IPV4:
+               dscp = ipv4_get_dsfield(ip_hdr(skb)) & ~INET_ECN_MASK;
+               if (dscp != newdscp) {
+                       if (likely(!skb_try_make_writable(skb, wlen))) {
+                               ipv4_change_dsfield(ip_hdr(skb),
+                                                   INET_ECN_MASK,
+                                                   newdscp);
+                               ca->stats_dscp_set++;
+                       } else {
+                               ca->stats_dscp_error++;
+                       }
+               }
+               break;
+       case NFPROTO_IPV6:
+               dscp = ipv6_get_dsfield(ipv6_hdr(skb)) & ~INET_ECN_MASK;
+               if (dscp != newdscp) {
+                       if (likely(!skb_try_make_writable(skb, wlen))) {
+                               ipv6_change_dsfield(ipv6_hdr(skb),
+                                                   INET_ECN_MASK,
+                                                   newdscp);
+                               ca->stats_dscp_set++;
+                       } else {
+                               ca->stats_dscp_error++;
+                       }
+               }
+               break;
+       default:
+               break;
+       }
+}
+
+static void tcf_ctinfo_cpmark_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
+                                 struct tcf_ctinfo_params *cp,
+                                 struct sk_buff *skb)
+{
+       ca->stats_cpmark_set++;
+       skb->mark = ct->mark & cp->cpmarkmask;
+}
+
+static int tcf_ctinfo_act(struct sk_buff *skb, const struct tc_action *a,
+                         struct tcf_result *res)
+{
+       const struct nf_conntrack_tuple_hash *thash = NULL;
+       struct tcf_ctinfo *ca = to_ctinfo(a);
+       struct nf_conntrack_tuple tuple;
+       struct nf_conntrack_zone zone;
+       enum ip_conntrack_info ctinfo;
+       struct tcf_ctinfo_params *cp;
+       struct nf_conn *ct;
+       int proto, wlen;
+       int action;
+
+       cp = rcu_dereference_bh(ca->params);
+
+       tcf_lastuse_update(&ca->tcf_tm);
+       bstats_update(&ca->tcf_bstats, skb);
+       action = READ_ONCE(ca->tcf_action);
+
+       wlen = skb_network_offset(skb);
+       if (tc_skb_protocol(skb) == htons(ETH_P_IP)) {
+               wlen += sizeof(struct iphdr);
+               if (!pskb_may_pull(skb, wlen))
+                       goto out;
+
+               proto = NFPROTO_IPV4;
+       } else if (tc_skb_protocol(skb) == htons(ETH_P_IPV6)) {
+               wlen += sizeof(struct ipv6hdr);
+               if (!pskb_may_pull(skb, wlen))
+                       goto out;
+
+               proto = NFPROTO_IPV6;
+       } else {
+               goto out;
+       }
+
+       ct = nf_ct_get(skb, &ctinfo);
+       if (!ct) { /* look harder, usually ingress */
+               if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
+                                      proto, cp->net, &tuple))
+                       goto out;
+               zone.id = cp->zone;
+               zone.dir = NF_CT_DEFAULT_ZONE_DIR;
+
+               thash = nf_conntrack_find_get(cp->net, &zone, &tuple);
+               if (!thash)
+                       goto out;
+
+               ct = nf_ct_tuplehash_to_ctrack(thash);
+       }
+
+       if (cp->mode & CTINFO_MODE_DSCP)
+               if (!cp->dscpstatemask || (ct->mark & cp->dscpstatemask))
+                       tcf_ctinfo_dscp_set(ct, ca, cp, skb, wlen, proto);
+
+       if (cp->mode & CTINFO_MODE_CPMARK)
+               tcf_ctinfo_cpmark_set(ct, ca, cp, skb);
+
+       if (thash)
+               nf_ct_put(ct);
+out:
+       return action;
+}
+
+static const struct nla_policy ctinfo_policy[TCA_CTINFO_MAX + 1] = {
+       [TCA_CTINFO_ACT]                  = { .len = sizeof(struct
+                                                           tc_ctinfo) },
+       [TCA_CTINFO_ZONE]                 = { .type = NLA_U16 },
+       [TCA_CTINFO_PARMS_DSCP_MASK]      = { .type = NLA_U32 },
+       [TCA_CTINFO_PARMS_DSCP_STATEMASK] = { .type = NLA_U32 },
+       [TCA_CTINFO_PARMS_CPMARK_MASK]    = { .type = NLA_U32 },
+};
+
+static int tcf_ctinfo_init(struct net *net, struct nlattr *nla,
+                          struct nlattr *est, struct tc_action **a,
+                          int ovr, int bind, bool rtnl_held,
+                          struct tcf_proto *tp,
+                          struct netlink_ext_ack *extack)
+{
+       struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
+       struct nlattr *tb[TCA_CTINFO_MAX + 1];
+       struct tcf_ctinfo_params *cp_new;
+       struct tcf_chain *goto_ch = NULL;
+       u32 dscpmask = 0, dscpstatemask;
+       struct tc_ctinfo *actparm;
+       struct tcf_ctinfo *ci;
+       u8 dscpmaskshift;
+       int ret = 0, err;
+
+       if (!nla)
+               return -EINVAL;
+
+       err = nla_parse_nested(tb, TCA_CTINFO_MAX, nla, ctinfo_policy, NULL);
+       if (err < 0)
+               return err;
+
+       if (!tb[TCA_CTINFO_ACT])
+               return -EINVAL;
+       actparm = nla_data(tb[TCA_CTINFO_ACT]);
+
+       /* do some basic validation here before dynamically allocating things */
+       /* that we would otherwise have to clean up.                          */
+       if (tb[TCA_CTINFO_PARMS_DSCP_MASK]) {
+               dscpmask = nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_MASK]);
+               /* need contiguous 6 bit mask */
+               dscpmaskshift = dscpmask ? __ffs(dscpmask) : 0;
+               if ((~0 & (dscpmask >> dscpmaskshift)) != 0x3f)
+                       return -EINVAL;
+               dscpstatemask = tb[TCA_CTINFO_PARMS_DSCP_STATEMASK] ?
+                       nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_STATEMASK]) : 0;
+               /* mask & statemask must not overlap */
+               if (dscpmask & dscpstatemask)
+                       return -EINVAL;
+       }
+
+       /* done the validation:now to the actual action allocation */
+       err = tcf_idr_check_alloc(tn, &actparm->index, a, bind);
+       if (!err) {
+               ret = tcf_idr_create(tn, actparm->index, est, a,
+                                    &act_ctinfo_ops, bind, false);
+               if (ret) {
+                       tcf_idr_cleanup(tn, actparm->index);
+                       return ret;
+               }
+       } else if (err > 0) {
+               if (bind) /* don't override defaults */
+                       return 0;
+               if (!ovr) {
+                       tcf_idr_release(*a, bind);
+                       return -EEXIST;
+               }
+       } else {
+               return err;
+       }
+
+       err = tcf_action_check_ctrlact(actparm->action, tp, &goto_ch, extack);
+       if (err < 0)
+               goto release_idr;
+
+       ci = to_ctinfo(*a);
+
+       cp_new = kzalloc(sizeof(*cp_new), GFP_KERNEL);
+       if (unlikely(!cp_new)) {
+               err = -ENOMEM;
+               goto put_chain;
+       }
+
+       cp_new->net = net;
+       cp_new->zone = tb[TCA_CTINFO_ZONE] ?
+                       nla_get_u16(tb[TCA_CTINFO_ZONE]) : 0;
+       if (dscpmask) {
+               cp_new->dscpmask = dscpmask;
+               cp_new->dscpmaskshift = dscpmaskshift;
+               cp_new->dscpstatemask = dscpstatemask;
+               cp_new->mode |= CTINFO_MODE_DSCP;
+       } else {
+               cp_new->mode &= ~CTINFO_MODE_DSCP;
+       }
+
+       if (tb[TCA_CTINFO_PARMS_CPMARK_MASK]) {
+               cp_new->cpmarkmask =
+                               nla_get_u32(tb[TCA_CTINFO_PARMS_CPMARK_MASK]);
+               cp_new->mode |= CTINFO_MODE_CPMARK;
+       } else {
+               cp_new->mode &= ~CTINFO_MODE_CPMARK;
+       }
+
+       spin_lock_bh(&ci->tcf_lock);
+       goto_ch = tcf_action_set_ctrlact(*a, actparm->action, goto_ch);
+       rcu_swap_protected(ci->params, cp_new,
+                          lockdep_is_held(&ci->tcf_lock));
+       spin_unlock_bh(&ci->tcf_lock);
+
+       if (goto_ch)
+               tcf_chain_put_by_act(goto_ch);
+       if (cp_new)
+               kfree_rcu(cp_new, rcu);
+
+       if (ret == ACT_P_CREATED)
+               tcf_idr_insert(tn, *a);
+
+       return ret;
+
+put_chain:
+       if (goto_ch)
+               tcf_chain_put_by_act(goto_ch);
+release_idr:
+       tcf_idr_release(*a, bind);
+       return err;
+}
+
+static int tcf_ctinfo_dump(struct sk_buff *skb, struct tc_action *a,
+                          int bind, int ref)
+{
+       struct tcf_ctinfo *ci = to_ctinfo(a);
+       struct tc_ctinfo opt = {
+               .index   = ci->tcf_index,
+               .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
+               .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
+       };
+       unsigned char *b = skb_tail_pointer(skb);
+       struct tcf_ctinfo_params *cp;
+       struct tcf_t t;
+
+       spin_lock_bh(&ci->tcf_lock);
+       cp = rcu_dereference_protected(ci->params,
+                                      lockdep_is_held(&ci->tcf_lock));
+
+       tcf_tm_dump(&t, &ci->tcf_tm);
+       if (nla_put_64bit(skb, TCA_CTINFO_TM, sizeof(t), &t, TCA_CTINFO_PAD))
+               goto nla_put_failure;
+
+       opt.action = ci->tcf_action;
+       if (nla_put(skb, TCA_CTINFO_ACT, sizeof(opt), &opt))
+               goto nla_put_failure;
+
+       if (nla_put_u16(skb, TCA_CTINFO_ZONE, cp->zone))
+               goto nla_put_failure;
+
+       if (cp->mode & CTINFO_MODE_DSCP) {
+               if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_MASK,
+                               cp->dscpmask))
+                       goto nla_put_failure;
+               if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_STATEMASK,
+                               cp->dscpstatemask))
+                       goto nla_put_failure;
+       }
+
+       if (cp->mode & CTINFO_MODE_CPMARK) {
+               if (nla_put_u32(skb, TCA_CTINFO_PARMS_CPMARK_MASK,
+                               cp->cpmarkmask))
+                       goto nla_put_failure;
+       }
+
+       if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_SET,
+                             ci->stats_dscp_set, TCA_CTINFO_PAD))
+               goto nla_put_failure;
+
+       if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_ERROR,
+                             ci->stats_dscp_error, TCA_CTINFO_PAD))
+               goto nla_put_failure;
+
+       if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_CPMARK_SET,
+                             ci->stats_cpmark_set, TCA_CTINFO_PAD))
+               goto nla_put_failure;
+
+       spin_unlock_bh(&ci->tcf_lock);
+       return skb->len;
+
+nla_put_failure:
+       spin_unlock_bh(&ci->tcf_lock);
+       nlmsg_trim(skb, b);
+       return -1;
+}
+
+static int tcf_ctinfo_walker(struct net *net, struct sk_buff *skb,
+                            struct netlink_callback *cb, int type,
+                            const struct tc_action_ops *ops,
+                            struct netlink_ext_ack *extack)
+{
+       struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
+
+       return tcf_generic_walker(tn, skb, cb, type, ops, extack);
+}
+
+static int tcf_ctinfo_search(struct net *net, struct tc_action **a, u32 index)
+{
+       struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
+
+       return tcf_idr_search(tn, a, index);
+}
+
+static struct tc_action_ops act_ctinfo_ops = {
+       .kind   = "ctinfo",
+       .id     = TCA_ID_CTINFO,
+       .owner  = THIS_MODULE,
+       .act    = tcf_ctinfo_act,
+       .dump   = tcf_ctinfo_dump,
+       .init   = tcf_ctinfo_init,
+       .walk   = tcf_ctinfo_walker,
+       .lookup = tcf_ctinfo_search,
+       .size   = sizeof(struct tcf_ctinfo),
+};
+
+static __net_init int ctinfo_init_net(struct net *net)
+{
+       struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
+
+       return tc_action_net_init(tn, &act_ctinfo_ops);
+}
+
+static void __net_exit ctinfo_exit_net(struct list_head *net_list)
+{
+       tc_action_net_exit(net_list, ctinfo_net_id);
+}
+
+static struct pernet_operations ctinfo_net_ops = {
+       .init           = ctinfo_init_net,
+       .exit_batch     = ctinfo_exit_net,
+       .id             = &ctinfo_net_id,
+       .size           = sizeof(struct tc_action_net),
+};
+
+static int __init ctinfo_init_module(void)
+{
+       return tcf_register_action(&act_ctinfo_ops, &ctinfo_net_ops);
+}
+
+static void __exit ctinfo_cleanup_module(void)
+{
+       tcf_unregister_action(&act_ctinfo_ops, &ctinfo_net_ops);
+}
+
+module_init(ctinfo_init_module);
+module_exit(ctinfo_cleanup_module);
+MODULE_AUTHOR("Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>");
+MODULE_DESCRIPTION("Connection tracking mark actions");
+MODULE_LICENSE("GPL");