ctinfo is a new tc filter action module. It is designed to restore information contained in conntrack marks to other places. At present it can restore DSCP values to IPv4/6 diffserv fields and also copy conntrack marks to skb marks. As such the 2nd function effectively replaces the existing act_connmark module
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 CAKE to shape inbound packets according to policies that are easier to indicate 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.
ctinfo understands the following parameters:
dscp dscpmask[/statemask]
dscpmask - a 32 bit mask of at least 6 contiguous bits and indicates where ctinfo will find the DSCP bits stored in the conntrack mark.
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)
mark [mask]
mark - enables copying the conntrack connmark value to the skb mark
mask - a 32 bit mask applied to the mark to mask out bit unwanted for restoration. The CAKE qdisc for example understands both DSCP and 'tin' classification stored the mark, thus act_ctinfo may be used to restore both aspects of classification for CAKE in one action. A default mask of 0xffffffff is applied if not specified.
zone - conntrack zone
control - action related control (reclassify | pipe | drop | continue | ok | goto chain <CHAIN_INDEX>)
e.g. dscp 0xfc000000/0x01000000
|----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 | |-------------|
e.g. mark 0x00ffffff
|----0x00----conntrack mark----ffffff---| | Bits 31-24 | | | DSCP & flag| | |---------------------------------------| | | v |------------skb mark-------------------| | | | | |---------------------------------------|
Signed-off-by: Kevin Darbyshire-Bryant ldir@darbyshire-bryant.me.uk --- v2 - add equivalent connmark functionality with an enhancement to accept a mask pass statistics for each sub-function as individual netlink attributes and stop (ab)using overlimits, drops update the testing config correctly v3 - fix a licensing silly & tidy up GPL boilerplate
include/net/tc_act/tc_ctinfo.h | 28 ++ include/uapi/linux/pkt_cls.h | 1 + include/uapi/linux/tc_act/tc_ctinfo.h | 43 +++ net/sched/Kconfig | 17 + net/sched/Makefile | 1 + net/sched/act_ctinfo.c | 402 ++++++++++++++++++++++ tools/testing/selftests/tc-testing/config | 1 + 7 files changed, 493 insertions(+) create mode 100644 include/net/tc_act/tc_ctinfo.h create mode 100644 include/uapi/linux/tc_act/tc_ctinfo.h create mode 100644 net/sched/act_ctinfo.c
diff --git a/include/net/tc_act/tc_ctinfo.h b/include/net/tc_act/tc_ctinfo.h new file mode 100644 index 000000000000..87334120dcb6 --- /dev/null +++ b/include/net/tc_act/tc_ctinfo.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __NET_TC_CTINFO_H +#define __NET_TC_CTINFO_H + +#include <net/act_api.h> + +struct tcf_ctinfo_params { + struct net *net; + u32 dscpmask; + u32 dscpstatemask; + u32 markmask; + u16 zone; + u8 mode; + u8 dscpmaskshift; + struct rcu_head rcu; +}; + +struct tcf_ctinfo { + struct tc_action common; + struct tcf_ctinfo_params __rcu *params; + u64 stats_dscp_set; + u64 stats_dscp_error; + u64 stats_mark_set; +}; + +#define to_ctinfo(a) ((struct tcf_ctinfo *)a) + +#endif /* __NET_TC_CTINFO_H */ diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h index 51a0496f78ea..a93680fc4bfa 100644 --- a/include/uapi/linux/pkt_cls.h +++ b/include/uapi/linux/pkt_cls.h @@ -105,6 +105,7 @@ enum tca_id { TCA_ID_IFE = TCA_ACT_IFE, TCA_ID_SAMPLE = TCA_ACT_SAMPLE, /* other actions go here */ + TCA_ID_CTINFO, __TCA_ID_MAX = 255 };
diff --git a/include/uapi/linux/tc_act/tc_ctinfo.h b/include/uapi/linux/tc_act/tc_ctinfo.h new file mode 100644 index 000000000000..8d254b82151c --- /dev/null +++ b/include/uapi/linux/tc_act/tc_ctinfo.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __UAPI_TC_CTINFO_H +#define __UAPI_TC_CTINFO_H + +#include <linux/types.h> +#include <linux/pkt_cls.h> + +struct tc_ctinfo { + tc_gen; +}; + +struct tc_ctinfo_dscp { + __u32 mask; + __u32 statemask; +}; + +struct tc_ctinfo_stats_dscp { + __u64 set; + __u64 error; +}; + +enum { + TCA_CTINFO_UNSPEC, + TCA_CTINFO_ACT, + TCA_CTINFO_ZONE, + TCA_CTINFO_DSCP_PARMS, + TCA_CTINFO_MARK_MASK, + TCA_CTINFO_MODE_DSCP, + TCA_CTINFO_MODE_MARK, + TCA_CTINFO_STATS_DSCP, + TCA_CTINFO_STATS_MARK, + TCA_CTINFO_TM, + TCA_CTINFO_PAD, + __TCA_CTINFO_MAX +}; +#define TCA_CTINFO_MAX (__TCA_CTINFO_MAX - 1) + +enum { + CTINFO_MODE_SETDSCP = BIT(0), + CTINFO_MODE_SETMARK = BIT(1) +}; + +#endif diff --git a/net/sched/Kconfig b/net/sched/Kconfig index 5c02ad97ef23..f5773effcfdc 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -876,6 +876,23 @@ config NET_ACT_CONNMARK To compile this code as a module, choose M here: the module will be called act_connmark.
+config NET_ACT_CTINFO + tristate "Netfilter Connection Mark Actions" + depends on NET_CLS_ACT && NETFILTER && IP_NF_IPTABLES + depends on NF_CONNTRACK && NF_CONNTRACK_MARK + help + Say Y here to allow transfer of a connmark stored information. + Current actions transfer connmark stored DSCP into + ipv4/v6 diffserv and/or to transfer connmark to packet + mark. Both are useful for restoring egress based marks + back onto ingress connections for qdisc priority mapping + purposes. + + If unsure, say N. + + To compile this code as a module, choose M here: the + module will be called act_ctinfo. + config NET_ACT_SKBMOD tristate "skb data modification action" depends on NET_CLS_ACT diff --git a/net/sched/Makefile b/net/sched/Makefile index 8a40431d7b5c..d54bfcbd7981 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -21,6 +21,7 @@ obj-$(CONFIG_NET_ACT_CSUM) += act_csum.o obj-$(CONFIG_NET_ACT_VLAN) += act_vlan.o obj-$(CONFIG_NET_ACT_BPF) += act_bpf.o obj-$(CONFIG_NET_ACT_CONNMARK) += act_connmark.o +obj-$(CONFIG_NET_ACT_CTINFO) += act_ctinfo.o obj-$(CONFIG_NET_ACT_SKBMOD) += act_skbmod.o obj-$(CONFIG_NET_ACT_IFE) += act_ife.o obj-$(CONFIG_NET_IFE_SKBMARK) += act_meta_mark.o diff --git a/net/sched/act_ctinfo.c b/net/sched/act_ctinfo.c new file mode 100644 index 000000000000..261807b222ca --- /dev/null +++ b/net/sched/act_ctinfo.c @@ -0,0 +1,402 @@ +// 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 unsigned int ctinfo_net_id; +static struct tc_action_ops act_ctinfo_ops; + +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_mark_set(struct nf_conn *ct, struct tcf_ctinfo *ca, + struct tcf_ctinfo_params *cp, + struct sk_buff *skb) +{ + ca->stats_mark_set++; + skb->mark = ct->mark & cp->markmask; +} + +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 nf_conntrack_tuple tuple; + enum ip_conntrack_info ctinfo; + struct tcf_ctinfo *ca = to_ctinfo(a); + struct tcf_ctinfo_params *cp; + struct nf_conntrack_zone zone; + 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_SETDSCP) + if (!cp->dscpstatemask || (ct->mark & cp->dscpstatemask)) + tcf_ctinfo_dscp_set(ct, ca, cp, skb, wlen, proto); + + if (cp->mode & CTINFO_MODE_SETMARK) + tcf_ctinfo_mark_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_MODE_DSCP] = { .type = NLA_FLAG }, + [TCA_CTINFO_MODE_MARK] = { .type = NLA_FLAG }, + [TCA_CTINFO_DSCP_PARMS] = { .len = sizeof(struct tc_ctinfo_dscp) }, +}; + +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 tcf_ctinfo_params *cp_new; + struct nlattr *tb[TCA_CTINFO_MAX + 1]; + struct tcf_chain *goto_ch = NULL; + struct tcf_ctinfo *ci; + struct tc_ctinfo *actparm; + struct tc_ctinfo_dscp *dscpparm; + int ret = 0, err, i; + + 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; + + if (tb[TCA_CTINFO_MODE_DSCP] && !tb[TCA_CTINFO_DSCP_PARMS]) + return -EINVAL; + + actparm = nla_data(tb[TCA_CTINFO_ACT]); + dscpparm = nla_data(tb[TCA_CTINFO_DSCP_PARMS]); + + if (dscpparm) { + /* need at least contiguous 6 bit mask */ + i = dscpparm->mask ? __ffs(dscpparm->mask) : 0; + if ((0x3f & (dscpparm->mask >> i)) != 0x3f) + return -EINVAL; + /* mask & statemask must not overlap */ + if (dscpparm->mask & dscpparm->statemask) + 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 (dscpparm) { + cp_new->dscpmask = dscpparm->mask; + cp_new->dscpmaskshift = cp_new->dscpmask ? + __ffs(cp_new->dscpmask) : 0; + cp_new->dscpstatemask = dscpparm->statemask; + } + cp_new->markmask = tb[TCA_CTINFO_MARK_MASK] ? + nla_get_u32(tb[TCA_CTINFO_MARK_MASK]) : ~0; + + if (tb[TCA_CTINFO_MODE_DSCP]) + cp_new->mode |= CTINFO_MODE_SETDSCP; + else + cp_new->mode &= ~CTINFO_MODE_SETDSCP; + + if (tb[TCA_CTINFO_MODE_MARK]) + cp_new->mode |= CTINFO_MODE_SETMARK; + else + cp_new->mode &= ~CTINFO_MODE_SETMARK; + + 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 inline int tcf_ctinfo_dump(struct sk_buff *skb, struct tc_action *a, + int bind, int ref) +{ + unsigned char *b = skb_tail_pointer(skb); + struct tcf_ctinfo *ci = to_ctinfo(a); + struct tcf_ctinfo_params *cp; + struct tc_ctinfo opt = { + .index = ci->tcf_index, + .refcnt = refcount_read(&ci->tcf_refcnt) - ref, + .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind, + }; + struct tcf_t t; + struct tc_ctinfo_dscp dscpparm; + struct tc_ctinfo_stats_dscp dscpstats; + + spin_lock_bh(&ci->tcf_lock); + cp = rcu_dereference_protected(ci->params, + lockdep_is_held(&ci->tcf_lock)); + opt.action = ci->tcf_action; + + if (nla_put(skb, TCA_CTINFO_ACT, sizeof(opt), &opt)) + goto nla_put_failure; + + if (cp->mode & CTINFO_MODE_SETDSCP) { + dscpparm.mask = cp->dscpmask; + dscpparm.statemask = cp->dscpstatemask; + if (nla_put(skb, TCA_CTINFO_DSCP_PARMS, sizeof(dscpparm), + &dscpparm)) + goto nla_put_failure; + + if (nla_put_flag(skb, TCA_CTINFO_MODE_DSCP)) + goto nla_put_failure; + + dscpstats.set = ci->stats_dscp_set; + dscpstats.error = ci->stats_dscp_error; + if (nla_put(skb, TCA_CTINFO_STATS_DSCP, sizeof(dscpstats), + &dscpstats)) + goto nla_put_failure; + } + + if (cp->mode & CTINFO_MODE_SETMARK) { + if (nla_put_u32(skb, TCA_CTINFO_MARK_MASK, cp->markmask)) + goto nla_put_failure; + + if (nla_put_flag(skb, TCA_CTINFO_MODE_MARK)) + goto nla_put_failure; + + if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_MARK, + ci->stats_mark_set, TCA_CTINFO_PAD)) + goto nla_put_failure; + } + + if (cp->zone) { + if (nla_put_u16(skb, TCA_CTINFO_ZONE, cp->zone)) + goto nla_put_failure; + } + + 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; + + 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"); diff --git a/tools/testing/selftests/tc-testing/config b/tools/testing/selftests/tc-testing/config index 203302065458..b235efd55367 100644 --- a/tools/testing/selftests/tc-testing/config +++ b/tools/testing/selftests/tc-testing/config @@ -38,6 +38,7 @@ CONFIG_NET_ACT_CSUM=m CONFIG_NET_ACT_VLAN=m CONFIG_NET_ACT_BPF=m CONFIG_NET_ACT_CONNMARK=m +CONFIG_NET_ACT_CTINFO=m CONFIG_NET_ACT_SKBMOD=m CONFIG_NET_ACT_IFE=m CONFIG_NET_ACT_TUNNEL_KEY=m