From 24ec483cec981618f8a4782a36d1e3f319d42cad Mon Sep 17 00:00:00 2001 From: Kevin 'ldir' Darbyshire-Bryant Date: Tue, 28 May 2019 17:03:50 +0000 Subject: net: sched: Introduce act_ctinfo action MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ctinfo is a new tc filter action module. It is designed to restore information contained in firewall conntrack marks to other packet fields and is typically used on packet ingress paths. At present it has two independent sub-functions or operating modes, DSCP restoration mode & skb mark restoration mode. The DSCP restore mode: This mode copies DSCP values that have been placed in the firewall conntrack mark back into the IPv4/v6 diffserv fields of relevant packets. The DSCP restoration is intended for use and has been found useful for restoring ingress classifications based on egress classifications across links that bleach or otherwise change DSCP, typically home ISP Internet links. Restoring DSCP on ingress on the WAN link allows qdiscs such as but by no means limited to CAKE to shape inbound packets according to policies that are easier to set & mark on egress. Ingress classification is traditionally a challenging task since iptables rules haven't yet run and tc filter/eBPF programs are pre-NAT lookups, hence are unable to see internal IPv4 addresses as used on the typical home masquerading gateway. Thus marking the connection in some manner on egress for later restoration of classification on ingress is easier to implement. Parameters related to DSCP restore mode: dscpmask - a 32 bit mask of 6 contiguous bits and indicate bits of the conntrack mark field contain the DSCP value to be restored. statemask - a 32 bit mask of (usually) 1 bit length, outside the area specified by dscpmask. This represents a conditional operation flag whereby the DSCP is only restored if the flag is set. This is useful to implement a 'one shot' iptables based classification where the 'complicated' iptables rules are only run once to classify the connection on initial (egress) packet and subsequent packets are all marked/restored with the same DSCP. A mask of zero disables the conditional behaviour ie. the conntrack mark DSCP bits are always restored to the ip diffserv field (assuming the conntrack entry is found & the skb is an ipv4/ipv6 type) e.g. dscpmask 0xfc000000 statemask 0x01000000 |----0xFC----conntrack mark----000000---| | Bits 31-26 | bit 25 | bit24 |~~~ Bit 0| | DSCP | unused | flag |unused | |-----------------------0x01---000000---| | | | | ---| Conditional flag v only restore if set |-ip diffserv-| | 6 bits | |-------------| The skb mark restore mode (cpmark): This mode copies the firewall conntrack mark to the skb's mark field. It is completely the functional equivalent of the existing act_connmark action with the additional feature of being able to apply a mask to the restored value. Parameters related to skb mark restore mode: mask - a 32 bit mask applied to the firewall conntrack mark to mask out bits unwanted for restoration. This can be useful where the conntrack mark is being used for different purposes by different applications. If not specified and by default the whole mark field is copied (i.e. default mask of 0xffffffff) e.g. mask 0x00ffffff to mask out the top 8 bits being used by the aforementioned DSCP restore mode. |----0x00----conntrack mark----ffffff---| | Bits 31-24 | | | DSCP & flag| some value here | |---------------------------------------| | | v |------------skb mark-------------------| | | | | zeroed | | |---------------------------------------| Overall parameters: zone - conntrack zone control - action related control (reclassify | pipe | drop | continue | ok | goto chain ) Signed-off-by: Kevin Darbyshire-Bryant Reviewed-by: Toke Høiland-Jørgensen Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/act_ctinfo.c | 396 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 396 insertions(+) create mode 100644 net/sched/act_ctinfo.c (limited to 'net/sched/act_ctinfo.c') diff --git a/net/sched/act_ctinfo.c b/net/sched/act_ctinfo.c new file mode 100644 index 000000000000..926109139a81 --- /dev/null +++ b/net/sched/act_ctinfo.c @@ -0,0 +1,396 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* net/sched/act_ctinfo.c netfilter ctinfo connmark actions + * + * Copyright (c) 2019 Kevin Darbyshire-Bryant + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +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 "); +MODULE_DESCRIPTION("Connection tracking mark actions"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3