diff options
Diffstat (limited to 'net/sched/act_skbmod.c')
| -rw-r--r-- | net/sched/act_skbmod.c | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c new file mode 100644 index 000000000..d98758a63 --- /dev/null +++ b/net/sched/act_skbmod.c @@ -0,0 +1,323 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * net/sched/act_skbmod.c skb data modifier + * + * Copyright (c) 2016 Jamal Hadi Salim <jhs@mojatatu.com> +*/ + +#include <linux/module.h> +#include <linux/if_arp.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/skbuff.h> +#include <linux/rtnetlink.h> +#include <net/inet_ecn.h> +#include <net/netlink.h> +#include <net/pkt_sched.h> +#include <net/pkt_cls.h> + +#include <linux/tc_act/tc_skbmod.h> +#include <net/tc_act/tc_skbmod.h> + +static struct tc_action_ops act_skbmod_ops; + +static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a, + struct tcf_result *res) +{ + struct tcf_skbmod *d = to_skbmod(a); + int action, max_edit_len, err; + struct tcf_skbmod_params *p; + u64 flags; + + tcf_lastuse_update(&d->tcf_tm); + bstats_update(this_cpu_ptr(d->common.cpu_bstats), skb); + + action = READ_ONCE(d->tcf_action); + if (unlikely(action == TC_ACT_SHOT)) + goto drop; + + max_edit_len = skb_mac_header_len(skb); + p = rcu_dereference_bh(d->skbmod_p); + flags = p->flags; + + /* tcf_skbmod_init() guarantees "flags" to be one of the following: + * 1. a combination of SKBMOD_F_{DMAC,SMAC,ETYPE} + * 2. SKBMOD_F_SWAPMAC + * 3. SKBMOD_F_ECN + * SKBMOD_F_ECN only works with IP packets; all other flags only work with Ethernet + * packets. + */ + if (flags == SKBMOD_F_ECN) { + switch (skb_protocol(skb, true)) { + case cpu_to_be16(ETH_P_IP): + case cpu_to_be16(ETH_P_IPV6): + max_edit_len += skb_network_header_len(skb); + break; + default: + goto out; + } + } else if (!skb->dev || skb->dev->type != ARPHRD_ETHER) { + goto out; + } + + err = skb_ensure_writable(skb, max_edit_len); + if (unlikely(err)) /* best policy is to drop on the floor */ + goto drop; + + if (flags & SKBMOD_F_DMAC) + ether_addr_copy(eth_hdr(skb)->h_dest, p->eth_dst); + if (flags & SKBMOD_F_SMAC) + ether_addr_copy(eth_hdr(skb)->h_source, p->eth_src); + if (flags & SKBMOD_F_ETYPE) + eth_hdr(skb)->h_proto = p->eth_type; + + if (flags & SKBMOD_F_SWAPMAC) { + u16 tmpaddr[ETH_ALEN / 2]; /* ether_addr_copy() requirement */ + /*XXX: I am sure we can come up with more efficient swapping*/ + ether_addr_copy((u8 *)tmpaddr, eth_hdr(skb)->h_dest); + ether_addr_copy(eth_hdr(skb)->h_dest, eth_hdr(skb)->h_source); + ether_addr_copy(eth_hdr(skb)->h_source, (u8 *)tmpaddr); + } + + if (flags & SKBMOD_F_ECN) + INET_ECN_set_ce(skb); + +out: + return action; + +drop: + qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats)); + return TC_ACT_SHOT; +} + +static const struct nla_policy skbmod_policy[TCA_SKBMOD_MAX + 1] = { + [TCA_SKBMOD_PARMS] = { .len = sizeof(struct tc_skbmod) }, + [TCA_SKBMOD_DMAC] = { .len = ETH_ALEN }, + [TCA_SKBMOD_SMAC] = { .len = ETH_ALEN }, + [TCA_SKBMOD_ETYPE] = { .type = NLA_U16 }, +}; + +static int tcf_skbmod_init(struct net *net, struct nlattr *nla, + struct nlattr *est, struct tc_action **a, + struct tcf_proto *tp, u32 flags, + struct netlink_ext_ack *extack) +{ + struct tc_action_net *tn = net_generic(net, act_skbmod_ops.net_id); + bool ovr = flags & TCA_ACT_FLAGS_REPLACE; + bool bind = flags & TCA_ACT_FLAGS_BIND; + struct nlattr *tb[TCA_SKBMOD_MAX + 1]; + struct tcf_skbmod_params *p, *p_old; + struct tcf_chain *goto_ch = NULL; + struct tc_skbmod *parm; + u32 lflags = 0, index; + struct tcf_skbmod *d; + bool exists = false; + u8 *daddr = NULL; + u8 *saddr = NULL; + u16 eth_type = 0; + int ret = 0, err; + + if (!nla) + return -EINVAL; + + err = nla_parse_nested_deprecated(tb, TCA_SKBMOD_MAX, nla, + skbmod_policy, NULL); + if (err < 0) + return err; + + if (!tb[TCA_SKBMOD_PARMS]) + return -EINVAL; + + if (tb[TCA_SKBMOD_DMAC]) { + daddr = nla_data(tb[TCA_SKBMOD_DMAC]); + lflags |= SKBMOD_F_DMAC; + } + + if (tb[TCA_SKBMOD_SMAC]) { + saddr = nla_data(tb[TCA_SKBMOD_SMAC]); + lflags |= SKBMOD_F_SMAC; + } + + if (tb[TCA_SKBMOD_ETYPE]) { + eth_type = nla_get_u16(tb[TCA_SKBMOD_ETYPE]); + lflags |= SKBMOD_F_ETYPE; + } + + parm = nla_data(tb[TCA_SKBMOD_PARMS]); + index = parm->index; + if (parm->flags & SKBMOD_F_SWAPMAC) + lflags = SKBMOD_F_SWAPMAC; + if (parm->flags & SKBMOD_F_ECN) + lflags = SKBMOD_F_ECN; + + err = tcf_idr_check_alloc(tn, &index, a, bind); + if (err < 0) + return err; + exists = err; + if (exists && bind) + return 0; + + if (!lflags) { + if (exists) + tcf_idr_release(*a, bind); + else + tcf_idr_cleanup(tn, index); + return -EINVAL; + } + + if (!exists) { + ret = tcf_idr_create(tn, index, est, a, + &act_skbmod_ops, bind, true, flags); + if (ret) { + tcf_idr_cleanup(tn, index); + return ret; + } + + ret = ACT_P_CREATED; + } else if (!ovr) { + tcf_idr_release(*a, bind); + return -EEXIST; + } + err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); + if (err < 0) + goto release_idr; + + d = to_skbmod(*a); + + p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL); + if (unlikely(!p)) { + err = -ENOMEM; + goto put_chain; + } + + p->flags = lflags; + + if (ovr) + spin_lock_bh(&d->tcf_lock); + /* Protected by tcf_lock if overwriting existing action. */ + goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); + p_old = rcu_dereference_protected(d->skbmod_p, 1); + + if (lflags & SKBMOD_F_DMAC) + ether_addr_copy(p->eth_dst, daddr); + if (lflags & SKBMOD_F_SMAC) + ether_addr_copy(p->eth_src, saddr); + if (lflags & SKBMOD_F_ETYPE) + p->eth_type = htons(eth_type); + + rcu_assign_pointer(d->skbmod_p, p); + if (ovr) + spin_unlock_bh(&d->tcf_lock); + + if (p_old) + kfree_rcu(p_old, rcu); + if (goto_ch) + tcf_chain_put_by_act(goto_ch); + + return ret; +put_chain: + if (goto_ch) + tcf_chain_put_by_act(goto_ch); +release_idr: + tcf_idr_release(*a, bind); + return err; +} + +static void tcf_skbmod_cleanup(struct tc_action *a) +{ + struct tcf_skbmod *d = to_skbmod(a); + struct tcf_skbmod_params *p; + + p = rcu_dereference_protected(d->skbmod_p, 1); + if (p) + kfree_rcu(p, rcu); +} + +static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a, + int bind, int ref) +{ + struct tcf_skbmod *d = to_skbmod(a); + unsigned char *b = skb_tail_pointer(skb); + struct tcf_skbmod_params *p; + struct tc_skbmod opt = { + .index = d->tcf_index, + .refcnt = refcount_read(&d->tcf_refcnt) - ref, + .bindcnt = atomic_read(&d->tcf_bindcnt) - bind, + }; + struct tcf_t t; + + spin_lock_bh(&d->tcf_lock); + opt.action = d->tcf_action; + p = rcu_dereference_protected(d->skbmod_p, + lockdep_is_held(&d->tcf_lock)); + opt.flags = p->flags; + if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt)) + goto nla_put_failure; + if ((p->flags & SKBMOD_F_DMAC) && + nla_put(skb, TCA_SKBMOD_DMAC, ETH_ALEN, p->eth_dst)) + goto nla_put_failure; + if ((p->flags & SKBMOD_F_SMAC) && + nla_put(skb, TCA_SKBMOD_SMAC, ETH_ALEN, p->eth_src)) + goto nla_put_failure; + if ((p->flags & SKBMOD_F_ETYPE) && + nla_put_u16(skb, TCA_SKBMOD_ETYPE, ntohs(p->eth_type))) + goto nla_put_failure; + + tcf_tm_dump(&t, &d->tcf_tm); + if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD)) + goto nla_put_failure; + + spin_unlock_bh(&d->tcf_lock); + return skb->len; +nla_put_failure: + spin_unlock_bh(&d->tcf_lock); + nlmsg_trim(skb, b); + return -1; +} + +static struct tc_action_ops act_skbmod_ops = { + .kind = "skbmod", + .id = TCA_ACT_SKBMOD, + .owner = THIS_MODULE, + .act = tcf_skbmod_act, + .dump = tcf_skbmod_dump, + .init = tcf_skbmod_init, + .cleanup = tcf_skbmod_cleanup, + .size = sizeof(struct tcf_skbmod), +}; + +static __net_init int skbmod_init_net(struct net *net) +{ + struct tc_action_net *tn = net_generic(net, act_skbmod_ops.net_id); + + return tc_action_net_init(net, tn, &act_skbmod_ops); +} + +static void __net_exit skbmod_exit_net(struct list_head *net_list) +{ + tc_action_net_exit(net_list, act_skbmod_ops.net_id); +} + +static struct pernet_operations skbmod_net_ops = { + .init = skbmod_init_net, + .exit_batch = skbmod_exit_net, + .id = &act_skbmod_ops.net_id, + .size = sizeof(struct tc_action_net), +}; + +MODULE_AUTHOR("Jamal Hadi Salim, <jhs@mojatatu.com>"); +MODULE_DESCRIPTION("SKB data mod-ing"); +MODULE_LICENSE("GPL"); + +static int __init skbmod_init_module(void) +{ + return tcf_register_action(&act_skbmod_ops, &skbmod_net_ops); +} + +static void __exit skbmod_cleanup_module(void) +{ + tcf_unregister_action(&act_skbmod_ops, &skbmod_net_ops); +} + +module_init(skbmod_init_module); +module_exit(skbmod_cleanup_module); |