![Davide Caratti](/assets/img/avatar_default.png)
the following script: # tc qdisc add dev crash0 clsact # tc filter add dev crash0 egress matchall \ > action vlan pop pass index 90 # tc actions replace action vlan \ > pop goto chain 42 index 90 cookie c1a0c1a0 # tc actions show action vlan had the following output: Error: Failed to init TC action chain. We have an error talking to the kernel total acts 1 action order 0: vlan pop goto chain 42 index 90 ref 2 bind 1 cookie c1a0c1a0 Then, the first packet transmitted by crash0 made the kernel crash: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [normal kernel read fault] PGD 800000007974f067 P4D 800000007974f067 PUD 79638067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.0.0-rc4.gotochain_crash+ #536 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:tcf_action_exec+0xb8/0x100 Code: 00 00 00 20 74 1d 83 f8 03 75 09 49 83 c4 08 4d 39 ec 75 bc 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 49 8b 97 a8 00 00 00 <48> 8b 12 48 89 55 00 48 83 c4 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 RSP: 0018:ffff982dfdb83be0 EFLAGS: 00010246 RAX: 000000002000002a RBX: ffff982dfc55db00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff982df97099c0 RDI: ffff982dfc55db00 RBP: ffff982dfdb83c80 R08: ffff982df983fec8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff982df5aacd00 R13: ffff982df5aacd08 R14: 0000000000000001 R15: ffff982df97099c0 FS: 0000000000000000(0000) GS:ffff982dfdb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000796d0005 CR4: 00000000001606e0 Call Trace: <IRQ> tcf_classify+0x58/0x120 __dev_queue_xmit+0x40a/0x890 ? ip6_finish_output2+0x369/0x590 ip6_finish_output2+0x369/0x590 ? ip6_output+0x68/0x110 ip6_output+0x68/0x110 ? nf_hook.constprop.35+0x79/0xc0 mld_sendpack+0x16f/0x220 mld_ifc_timer_expire+0x195/0x2c0 ? igmp6_timer_handler+0x70/0x70 call_timer_fn+0x2b/0x130 run_timer_softirq+0x3e8/0x440 ? enqueue_hrtimer+0x39/0x90 __do_softirq+0xe3/0x2f5 irq_exit+0xf0/0x100 smp_apic_timer_interrupt+0x6c/0x130 apic_timer_interrupt+0xf/0x20 </IRQ> RIP: 0010:native_safe_halt+0x2/0x10 Code: 7b ff ff ff 7f f3 c3 65 48 8b 04 25 00 5c 01 00 f0 80 48 02 20 48 8b 00 a8 08 74 8b eb c1 90 90 90 90 90 90 90 90 90 90 fb f4 <c3> 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f4 c3 90 90 90 90 90 90 RSP: 0018:ffffa4714038feb8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff840184f0 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000001e57d3f387 RBP: 0000000000000003 R08: 001125d9ca39e1eb R09: 0000000000000000 R10: 000000000000027d R11: 000000000009f400 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ? __sched_text_end+0x1/0x1 default_idle+0x1c/0x140 do_idle+0x1c4/0x280 cpu_startup_entry+0x19/0x20 start_secondary+0x1a7/0x200 secondary_startup_64+0xa4/0xb0 Modules linked in: act_vlan veth ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 snd_hda_codec_generic mbcache crct10dif_pclmul jbd2 snd_hda_intel crc32_pclmul snd_hda_codec ghash_clmulni_intel snd_hwdep snd_hda_core snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd cryptd glue_helper joydev snd_timer virtio_balloon snd pcspkr soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt virtio_net fb_sys_fops virtio_blk ttm net_failover virtio_console failover ata_piix drm libata crc32c_intel virtio_pci serio_raw virtio_ring virtio floppy dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000000 Validating the control action within tcf_vlan_init() proved to fix the above issue. A TDC selftest is added to verify the correct behavior. Fixes:db50514f9a
("net: sched: add termination action to allow goto chain") Fixes:97763dc0f4
("net_sched: reject unknown tcfa_action values") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
360 lines
8.6 KiB
C
360 lines
8.6 KiB
C
/*
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* Copyright (c) 2014 Jiri Pirko <jiri@resnulli.us>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/module.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 <linux/if_vlan.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_vlan.h>
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#include <net/tc_act/tc_vlan.h>
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static unsigned int vlan_net_id;
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static struct tc_action_ops act_vlan_ops;
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static int tcf_vlan_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_vlan *v = to_vlan(a);
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struct tcf_vlan_params *p;
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int action;
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int err;
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u16 tci;
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tcf_lastuse_update(&v->tcf_tm);
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bstats_cpu_update(this_cpu_ptr(v->common.cpu_bstats), skb);
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/* Ensure 'data' points at mac_header prior calling vlan manipulating
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* functions.
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*/
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if (skb_at_tc_ingress(skb))
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skb_push_rcsum(skb, skb->mac_len);
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action = READ_ONCE(v->tcf_action);
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p = rcu_dereference_bh(v->vlan_p);
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switch (p->tcfv_action) {
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case TCA_VLAN_ACT_POP:
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err = skb_vlan_pop(skb);
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if (err)
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goto drop;
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break;
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case TCA_VLAN_ACT_PUSH:
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err = skb_vlan_push(skb, p->tcfv_push_proto, p->tcfv_push_vid |
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(p->tcfv_push_prio << VLAN_PRIO_SHIFT));
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if (err)
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goto drop;
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break;
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case TCA_VLAN_ACT_MODIFY:
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/* No-op if no vlan tag (either hw-accel or in-payload) */
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if (!skb_vlan_tagged(skb))
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goto out;
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/* extract existing tag (and guarantee no hw-accel tag) */
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if (skb_vlan_tag_present(skb)) {
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tci = skb_vlan_tag_get(skb);
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__vlan_hwaccel_clear_tag(skb);
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} else {
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/* in-payload vlan tag, pop it */
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err = __skb_vlan_pop(skb, &tci);
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if (err)
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goto drop;
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}
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/* replace the vid */
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tci = (tci & ~VLAN_VID_MASK) | p->tcfv_push_vid;
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/* replace prio bits, if tcfv_push_prio specified */
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if (p->tcfv_push_prio) {
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tci &= ~VLAN_PRIO_MASK;
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tci |= p->tcfv_push_prio << VLAN_PRIO_SHIFT;
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}
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/* put updated tci as hwaccel tag */
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__vlan_hwaccel_put_tag(skb, p->tcfv_push_proto, tci);
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break;
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default:
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BUG();
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}
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out:
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if (skb_at_tc_ingress(skb))
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skb_pull_rcsum(skb, skb->mac_len);
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return action;
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drop:
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qstats_drop_inc(this_cpu_ptr(v->common.cpu_qstats));
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return TC_ACT_SHOT;
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}
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static const struct nla_policy vlan_policy[TCA_VLAN_MAX + 1] = {
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[TCA_VLAN_PARMS] = { .len = sizeof(struct tc_vlan) },
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[TCA_VLAN_PUSH_VLAN_ID] = { .type = NLA_U16 },
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[TCA_VLAN_PUSH_VLAN_PROTOCOL] = { .type = NLA_U16 },
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[TCA_VLAN_PUSH_VLAN_PRIORITY] = { .type = NLA_U8 },
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};
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static int tcf_vlan_init(struct net *net, struct nlattr *nla,
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struct nlattr *est, struct tc_action **a,
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int ovr, int bind, bool rtnl_held,
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struct tcf_proto *tp, struct netlink_ext_ack *extack)
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{
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struct tc_action_net *tn = net_generic(net, vlan_net_id);
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struct nlattr *tb[TCA_VLAN_MAX + 1];
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struct tcf_chain *goto_ch = NULL;
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struct tcf_vlan_params *p;
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struct tc_vlan *parm;
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struct tcf_vlan *v;
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int action;
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u16 push_vid = 0;
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__be16 push_proto = 0;
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u8 push_prio = 0;
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bool exists = false;
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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(tb, TCA_VLAN_MAX, nla, vlan_policy, NULL);
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if (err < 0)
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return err;
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if (!tb[TCA_VLAN_PARMS])
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return -EINVAL;
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parm = nla_data(tb[TCA_VLAN_PARMS]);
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err = tcf_idr_check_alloc(tn, &parm->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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switch (parm->v_action) {
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case TCA_VLAN_ACT_POP:
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break;
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case TCA_VLAN_ACT_PUSH:
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case TCA_VLAN_ACT_MODIFY:
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if (!tb[TCA_VLAN_PUSH_VLAN_ID]) {
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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, parm->index);
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return -EINVAL;
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}
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push_vid = nla_get_u16(tb[TCA_VLAN_PUSH_VLAN_ID]);
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if (push_vid >= VLAN_VID_MASK) {
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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, parm->index);
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return -ERANGE;
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}
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if (tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]) {
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push_proto = nla_get_be16(tb[TCA_VLAN_PUSH_VLAN_PROTOCOL]);
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switch (push_proto) {
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case htons(ETH_P_8021Q):
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case htons(ETH_P_8021AD):
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break;
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default:
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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, parm->index);
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return -EPROTONOSUPPORT;
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}
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} else {
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push_proto = htons(ETH_P_8021Q);
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}
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if (tb[TCA_VLAN_PUSH_VLAN_PRIORITY])
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push_prio = nla_get_u8(tb[TCA_VLAN_PUSH_VLAN_PRIORITY]);
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break;
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default:
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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, parm->index);
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return -EINVAL;
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}
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action = parm->v_action;
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if (!exists) {
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ret = tcf_idr_create(tn, parm->index, est, a,
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&act_vlan_ops, bind, true);
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if (ret) {
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tcf_idr_cleanup(tn, parm->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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v = to_vlan(*a);
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p = kzalloc(sizeof(*p), GFP_KERNEL);
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if (!p) {
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err = -ENOMEM;
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goto put_chain;
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}
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p->tcfv_action = action;
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p->tcfv_push_vid = push_vid;
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p->tcfv_push_prio = push_prio;
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p->tcfv_push_proto = push_proto;
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spin_lock_bh(&v->tcf_lock);
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
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rcu_swap_protected(v->vlan_p, p, lockdep_is_held(&v->tcf_lock));
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spin_unlock_bh(&v->tcf_lock);
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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if (p)
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kfree_rcu(p, rcu);
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if (ret == ACT_P_CREATED)
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tcf_idr_insert(tn, *a);
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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_vlan_cleanup(struct tc_action *a)
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{
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struct tcf_vlan *v = to_vlan(a);
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struct tcf_vlan_params *p;
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p = rcu_dereference_protected(v->vlan_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_vlan_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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unsigned char *b = skb_tail_pointer(skb);
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struct tcf_vlan *v = to_vlan(a);
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struct tcf_vlan_params *p;
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struct tc_vlan opt = {
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.index = v->tcf_index,
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.refcnt = refcount_read(&v->tcf_refcnt) - ref,
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.bindcnt = atomic_read(&v->tcf_bindcnt) - bind,
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};
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struct tcf_t t;
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spin_lock_bh(&v->tcf_lock);
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opt.action = v->tcf_action;
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p = rcu_dereference_protected(v->vlan_p, lockdep_is_held(&v->tcf_lock));
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opt.v_action = p->tcfv_action;
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if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
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goto nla_put_failure;
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if ((p->tcfv_action == TCA_VLAN_ACT_PUSH ||
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p->tcfv_action == TCA_VLAN_ACT_MODIFY) &&
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(nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, p->tcfv_push_vid) ||
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nla_put_be16(skb, TCA_VLAN_PUSH_VLAN_PROTOCOL,
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p->tcfv_push_proto) ||
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(nla_put_u8(skb, TCA_VLAN_PUSH_VLAN_PRIORITY,
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p->tcfv_push_prio))))
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goto nla_put_failure;
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tcf_tm_dump(&t, &v->tcf_tm);
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if (nla_put_64bit(skb, TCA_VLAN_TM, sizeof(t), &t, TCA_VLAN_PAD))
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goto nla_put_failure;
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spin_unlock_bh(&v->tcf_lock);
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return skb->len;
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nla_put_failure:
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spin_unlock_bh(&v->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_vlan_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, vlan_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_vlan_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, vlan_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_vlan_ops = {
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.kind = "vlan",
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.id = TCA_ID_VLAN,
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.owner = THIS_MODULE,
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.act = tcf_vlan_act,
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.dump = tcf_vlan_dump,
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.init = tcf_vlan_init,
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.cleanup = tcf_vlan_cleanup,
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.walk = tcf_vlan_walker,
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.lookup = tcf_vlan_search,
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.size = sizeof(struct tcf_vlan),
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};
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static __net_init int vlan_init_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, vlan_net_id);
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return tc_action_net_init(tn, &act_vlan_ops);
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}
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static void __net_exit vlan_exit_net(struct list_head *net_list)
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{
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tc_action_net_exit(net_list, vlan_net_id);
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}
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static struct pernet_operations vlan_net_ops = {
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.init = vlan_init_net,
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.exit_batch = vlan_exit_net,
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.id = &vlan_net_id,
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.size = sizeof(struct tc_action_net),
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};
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static int __init vlan_init_module(void)
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{
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return tcf_register_action(&act_vlan_ops, &vlan_net_ops);
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}
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static void __exit vlan_cleanup_module(void)
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{
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tcf_unregister_action(&act_vlan_ops, &vlan_net_ops);
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}
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module_init(vlan_init_module);
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module_exit(vlan_cleanup_module);
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MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
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MODULE_DESCRIPTION("vlan manipulation actions");
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MODULE_LICENSE("GPL v2");
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