| /* |
| * net/sched/act_skbmod.c skb data modifier |
| * |
| * Copyright (c) 2016 Jamal Hadi Salim <jhs@mojatatu.com> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/skbuff.h> |
| #include <linux/rtnetlink.h> |
| #include <net/netlink.h> |
| #include <net/pkt_sched.h> |
| |
| #include <linux/tc_act/tc_skbmod.h> |
| #include <net/tc_act/tc_skbmod.h> |
| |
| static unsigned int skbmod_net_id; |
| static struct tc_action_ops act_skbmod_ops; |
| |
| #define MAX_EDIT_LEN ETH_HLEN |
| static int tcf_skbmod_run(struct sk_buff *skb, const struct tc_action *a, |
| struct tcf_result *res) |
| { |
| struct tcf_skbmod *d = to_skbmod(a); |
| int action; |
| struct tcf_skbmod_params *p; |
| u64 flags; |
| int err; |
| |
| tcf_lastuse_update(&d->tcf_tm); |
| bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb); |
| |
| /* XXX: if you are going to edit more fields beyond ethernet header |
| * (example when you add IP header replacement or vlan swap) |
| * then MAX_EDIT_LEN needs to change appropriately |
| */ |
| err = skb_ensure_writable(skb, MAX_EDIT_LEN); |
| if (unlikely(err)) { /* best policy is to drop on the floor */ |
| qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats)); |
| return TC_ACT_SHOT; |
| } |
| |
| rcu_read_lock(); |
| action = READ_ONCE(d->tcf_action); |
| if (unlikely(action == TC_ACT_SHOT)) { |
| qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats)); |
| rcu_read_unlock(); |
| return action; |
| } |
| |
| p = rcu_dereference(d->skbmod_p); |
| flags = p->flags; |
| 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; |
| rcu_read_unlock(); |
| |
| 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); |
| } |
| |
| return action; |
| } |
| |
| 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, |
| int ovr, int bind) |
| { |
| struct tc_action_net *tn = net_generic(net, skbmod_net_id); |
| struct nlattr *tb[TCA_SKBMOD_MAX + 1]; |
| struct tcf_skbmod_params *p, *p_old; |
| struct tc_skbmod *parm; |
| struct tcf_skbmod *d; |
| bool exists = false; |
| u8 *daddr = NULL; |
| u8 *saddr = NULL; |
| u16 eth_type = 0; |
| u32 lflags = 0; |
| int ret = 0, err; |
| |
| if (!nla) |
| return -EINVAL; |
| |
| err = nla_parse_nested(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]); |
| if (parm->flags & SKBMOD_F_SWAPMAC) |
| lflags = SKBMOD_F_SWAPMAC; |
| |
| exists = tcf_idr_check(tn, parm->index, a, bind); |
| if (exists && bind) |
| return 0; |
| |
| if (!lflags) |
| return -EINVAL; |
| |
| if (!exists) { |
| ret = tcf_idr_create(tn, parm->index, est, a, |
| &act_skbmod_ops, bind, true); |
| if (ret) |
| return ret; |
| |
| ret = ACT_P_CREATED; |
| } else { |
| tcf_idr_release(*a, bind); |
| if (!ovr) |
| return -EEXIST; |
| } |
| |
| d = to_skbmod(*a); |
| |
| ASSERT_RTNL(); |
| p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL); |
| if (unlikely(!p)) { |
| if (ovr) |
| tcf_idr_release(*a, bind); |
| return -ENOMEM; |
| } |
| |
| p->flags = lflags; |
| d->tcf_action = parm->action; |
| |
| p_old = rtnl_dereference(d->skbmod_p); |
| |
| if (ovr) |
| spin_lock_bh(&d->tcf_lock); |
| |
| 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 (ret == ACT_P_CREATED) |
| tcf_idr_insert(tn, *a); |
| return ret; |
| } |
| |
| static void tcf_skbmod_cleanup(struct tc_action *a, int bind) |
| { |
| 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 = rtnl_dereference(d->skbmod_p); |
| struct tc_skbmod opt = { |
| .index = d->tcf_index, |
| .refcnt = d->tcf_refcnt - ref, |
| .bindcnt = d->tcf_bindcnt - bind, |
| .action = d->tcf_action, |
| }; |
| struct tcf_t t; |
| |
| 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; |
| |
| return skb->len; |
| nla_put_failure: |
| nlmsg_trim(skb, b); |
| return -1; |
| } |
| |
| static int tcf_skbmod_walker(struct net *net, struct sk_buff *skb, |
| struct netlink_callback *cb, int type, |
| const struct tc_action_ops *ops) |
| { |
| struct tc_action_net *tn = net_generic(net, skbmod_net_id); |
| |
| return tcf_generic_walker(tn, skb, cb, type, ops); |
| } |
| |
| static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index) |
| { |
| struct tc_action_net *tn = net_generic(net, skbmod_net_id); |
| |
| return tcf_idr_search(tn, a, index); |
| } |
| |
| static struct tc_action_ops act_skbmod_ops = { |
| .kind = "skbmod", |
| .type = TCA_ACT_SKBMOD, |
| .owner = THIS_MODULE, |
| .act = tcf_skbmod_run, |
| .dump = tcf_skbmod_dump, |
| .init = tcf_skbmod_init, |
| .cleanup = tcf_skbmod_cleanup, |
| .walk = tcf_skbmod_walker, |
| .lookup = tcf_skbmod_search, |
| .size = sizeof(struct tcf_skbmod), |
| }; |
| |
| static __net_init int skbmod_init_net(struct net *net) |
| { |
| struct tc_action_net *tn = net_generic(net, skbmod_net_id); |
| |
| return tc_action_net_init(tn, &act_skbmod_ops); |
| } |
| |
| static void __net_exit skbmod_exit_net(struct net *net) |
| { |
| struct tc_action_net *tn = net_generic(net, skbmod_net_id); |
| |
| tc_action_net_exit(tn); |
| } |
| |
| static struct pernet_operations skbmod_net_ops = { |
| .init = skbmod_init_net, |
| .exit = skbmod_exit_net, |
| .id = &skbmod_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); |