openvswitch: add TTL decrement action
New action to decrement TTL instead of setting it to a fixed value.
This action will decrement the TTL and, in case of expired TTL, drop it
or execute an action passed via a nested attribute.
The default TTL expired action is to drop the packet.
Supports both IPv4 and IPv6 via the ttl and hop_limit fields, respectively.
Tested with a corresponding change in the userspace:
# ovs-dpctl dump-flows
in_port(2),eth(),eth_type(0x0800), packets:0, bytes:0, used:never, actions:dec_ttl{ttl<=1 action:(drop)},1
in_port(1),eth(),eth_type(0x0800), packets:0, bytes:0, used:never, actions:dec_ttl{ttl<=1 action:(drop)},2
in_port(1),eth(),eth_type(0x0806), packets:0, bytes:0, used:never, actions:2
in_port(2),eth(),eth_type(0x0806), packets:0, bytes:0, used:never, actions:1
# ping -c1 192.168.0.2 -t 42
IP (tos 0x0, ttl 41, id 61647, offset 0, flags [DF], proto ICMP (1), length 84)
192.168.0.1 > 192.168.0.2: ICMP echo request, id 386, seq 1, length 64
# ping -c1 192.168.0.2 -t 120
IP (tos 0x0, ttl 119, id 62070, offset 0, flags [DF], proto ICMP (1), length 84)
192.168.0.1 > 192.168.0.2: ICMP echo request, id 388, seq 1, length 64
# ping -c1 192.168.0.2 -t 1
#
Co-developed-by: Bindiya Kurle <bindiyakurle@gmail.com>
Signed-off-by: Bindiya Kurle <bindiyakurle@gmail.com>
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matteo Croce
David S. Miller
Родитель
7458bd540f
Коммит
744676e777
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@ -958,6 +958,7 @@ enum ovs_action_attr {
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OVS_ACTION_ATTR_CLONE, /* Nested OVS_CLONE_ATTR_*. */
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OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested OVS_CHECK_PKT_LEN_ATTR_*. */
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OVS_ACTION_ATTR_ADD_MPLS, /* struct ovs_action_add_mpls. */
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OVS_ACTION_ATTR_DEC_TTL, /* Nested OVS_DEC_TTL_ATTR_*. */
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__OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted
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* from userspace. */
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@ -1050,4 +1051,10 @@ struct ovs_zone_limit {
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__u32 count;
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};
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enum ovs_dec_ttl_attr {
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OVS_DEC_TTL_ATTR_UNSPEC,
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OVS_DEC_TTL_ATTR_ACTION, /* Nested struct nlattr */
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__OVS_DEC_TTL_ATTR_MAX
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};
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#endif /* _LINUX_OPENVSWITCH_H */
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@ -964,6 +964,25 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb,
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return ovs_dp_upcall(dp, skb, key, &upcall, cutlen);
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}
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static int dec_ttl_exception_handler(struct datapath *dp, struct sk_buff *skb,
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struct sw_flow_key *key,
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const struct nlattr *attr, bool last)
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{
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/* The first action is always 'OVS_DEC_TTL_ATTR_ARG'. */
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struct nlattr *dec_ttl_arg = nla_data(attr);
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int rem = nla_len(attr);
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if (nla_len(dec_ttl_arg)) {
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struct nlattr *actions = nla_next(dec_ttl_arg, &rem);
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if (actions)
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return clone_execute(dp, skb, key, 0, actions, rem,
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last, false);
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}
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consume_skb(skb);
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return 0;
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}
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/* When 'last' is true, sample() should always consume the 'skb'.
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* Otherwise, sample() should keep 'skb' intact regardless what
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* actions are executed within sample().
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@ -1180,6 +1199,45 @@ static int execute_check_pkt_len(struct datapath *dp, struct sk_buff *skb,
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nla_len(actions), last, clone_flow_key);
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}
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static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key)
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{
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int err;
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if (skb->protocol == htons(ETH_P_IPV6)) {
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struct ipv6hdr *nh;
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err = skb_ensure_writable(skb, skb_network_offset(skb) +
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sizeof(*nh));
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if (unlikely(err))
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return err;
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nh = ipv6_hdr(skb);
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if (nh->hop_limit <= 1)
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return -EHOSTUNREACH;
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key->ip.ttl = --nh->hop_limit;
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} else {
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struct iphdr *nh;
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u8 old_ttl;
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err = skb_ensure_writable(skb, skb_network_offset(skb) +
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sizeof(*nh));
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if (unlikely(err))
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return err;
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nh = ip_hdr(skb);
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if (nh->ttl <= 1)
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return -EHOSTUNREACH;
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old_ttl = nh->ttl--;
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csum_replace2(&nh->check, htons(old_ttl << 8),
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htons(nh->ttl << 8));
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key->ip.ttl = nh->ttl;
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}
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return 0;
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}
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/* Execute a list of actions against 'skb'. */
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static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
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struct sw_flow_key *key,
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@ -1365,6 +1423,15 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
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break;
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}
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case OVS_ACTION_ATTR_DEC_TTL:
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err = execute_dec_ttl(skb, key);
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if (err == -EHOSTUNREACH) {
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err = dec_ttl_exception_handler(dp, skb, key,
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a, true);
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return err;
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}
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break;
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}
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if (unlikely(err)) {
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@ -80,6 +80,7 @@ static bool actions_may_change_flow(const struct nlattr *actions)
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case OVS_ACTION_ATTR_METER:
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case OVS_ACTION_ATTR_CHECK_PKT_LEN:
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case OVS_ACTION_ATTR_ADD_MPLS:
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case OVS_ACTION_ATTR_DEC_TTL:
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default:
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return true;
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}
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@ -2495,6 +2496,39 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
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return 0;
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}
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static int validate_and_copy_dec_ttl(struct net *net,
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const struct nlattr *attr,
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const struct sw_flow_key *key,
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struct sw_flow_actions **sfa,
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__be16 eth_type, __be16 vlan_tci,
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u32 mpls_label_count, bool log)
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{
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int start, err;
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u32 nested = true;
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if (!nla_len(attr))
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return ovs_nla_add_action(sfa, OVS_ACTION_ATTR_DEC_TTL,
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NULL, 0, log);
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start = add_nested_action_start(sfa, OVS_ACTION_ATTR_DEC_TTL, log);
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if (start < 0)
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return start;
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err = ovs_nla_add_action(sfa, OVS_DEC_TTL_ATTR_ACTION, &nested,
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sizeof(nested), log);
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if (err)
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return err;
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err = __ovs_nla_copy_actions(net, attr, key, sfa, eth_type,
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vlan_tci, mpls_label_count, log);
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if (err)
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return err;
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add_nested_action_end(*sfa, start);
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return 0;
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}
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static int validate_and_copy_clone(struct net *net,
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const struct nlattr *attr,
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const struct sw_flow_key *key,
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@ -3007,6 +3041,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
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[OVS_ACTION_ATTR_CLONE] = (u32)-1,
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[OVS_ACTION_ATTR_CHECK_PKT_LEN] = (u32)-1,
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[OVS_ACTION_ATTR_ADD_MPLS] = sizeof(struct ovs_action_add_mpls),
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[OVS_ACTION_ATTR_DEC_TTL] = (u32)-1,
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};
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const struct ovs_action_push_vlan *vlan;
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int type = nla_type(a);
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@ -3267,6 +3302,15 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
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break;
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}
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case OVS_ACTION_ATTR_DEC_TTL:
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err = validate_and_copy_dec_ttl(net, a, key, sfa,
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eth_type, vlan_tci,
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mpls_label_count, log);
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if (err)
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return err;
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skip_copy = true;
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break;
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default:
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OVS_NLERR(log, "Unknown Action type %d", type);
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return -EINVAL;
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@ -3438,6 +3482,26 @@ out:
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return err;
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}
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static int dec_ttl_action_to_attr(const struct nlattr *attr,
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struct sk_buff *skb)
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{
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int err = 0, rem = nla_len(attr);
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struct nlattr *start;
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start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_DEC_TTL);
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if (!start)
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return -EMSGSIZE;
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err = ovs_nla_put_actions(nla_data(attr), rem, skb);
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if (err)
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nla_nest_cancel(skb, start);
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else
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nla_nest_end(skb, start);
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return err;
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}
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static int set_action_to_attr(const struct nlattr *a, struct sk_buff *skb)
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{
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const struct nlattr *ovs_key = nla_data(a);
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@ -3538,6 +3602,12 @@ int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
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return err;
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break;
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case OVS_ACTION_ATTR_DEC_TTL:
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err = dec_ttl_action_to_attr(a, skb);
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if (err)
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return err;
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break;
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default:
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if (nla_put(skb, type, nla_len(a), nla_data(a)))
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return -EMSGSIZE;
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