--- /dev/null
+/*
+ * 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>
+
+#define SKBMOD_TAB_MASK 15
+
+static 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);
+ 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_hash_check(tn, parm->index, a, bind);
+ if (exists && bind)
+ return 0;
+
+ if (!lflags)
+ return -EINVAL;
+
+ if (!exists) {
+ ret = tcf_hash_create(tn, parm->index, est, a,
+ &act_skbmod_ops, bind, true);
+ if (ret)
+ return ret;
+
+ ret = ACT_P_CREATED;
+ } else {
+ tcf_hash_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_hash_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_hash_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);
+ 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:
+ rcu_read_unlock();
+ 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_hash_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, SKBMOD_TAB_MASK);
+}
+
+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);
projects / GitHub / MotorolaMobilityLLC / kernel-slsi.git / commitdiff