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