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authorMatteo Croce <mcroce@redhat.com>2020-02-15 14:20:56 +0100
committerDavid S. Miller <davem@davemloft.net>2020-02-16 19:34:44 -0800
commit744676e777207f4992ba4cc728a8a71352963c5b (patch)
tree6e5ebfb7f6a28103ae554e949fefe2eba5ab8ff9 /net/openvswitch
parent7458bd540fa0a90220b9e8c349d910d9dde9caf8 (diff)
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>
Diffstat (limited to 'net/openvswitch')
-rw-r--r--net/openvswitch/actions.c67
-rw-r--r--net/openvswitch/flow_netlink.c70
2 files changed, 137 insertions, 0 deletions
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 7fbfe2adfffa..fc0efd8833c8 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -964,6 +964,25 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb,
return ovs_dp_upcall(dp, skb, key, &upcall, cutlen);
}
+static int dec_ttl_exception_handler(struct datapath *dp, struct sk_buff *skb,
+ struct sw_flow_key *key,
+ const struct nlattr *attr, bool last)
+{
+ /* The first action is always 'OVS_DEC_TTL_ATTR_ARG'. */
+ struct nlattr *dec_ttl_arg = nla_data(attr);
+ int rem = nla_len(attr);
+
+ if (nla_len(dec_ttl_arg)) {
+ struct nlattr *actions = nla_next(dec_ttl_arg, &rem);
+
+ if (actions)
+ return clone_execute(dp, skb, key, 0, actions, rem,
+ last, false);
+ }
+ consume_skb(skb);
+ return 0;
+}
+
/* When 'last' is true, sample() should always consume the 'skb'.
* Otherwise, sample() should keep 'skb' intact regardless what
* actions are executed within sample().
@@ -1180,6 +1199,45 @@ static int execute_check_pkt_len(struct datapath *dp, struct sk_buff *skb,
nla_len(actions), last, clone_flow_key);
}
+static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key)
+{
+ int err;
+
+ if (skb->protocol == htons(ETH_P_IPV6)) {
+ struct ipv6hdr *nh;
+
+ err = skb_ensure_writable(skb, skb_network_offset(skb) +
+ sizeof(*nh));
+ if (unlikely(err))
+ return err;
+
+ nh = ipv6_hdr(skb);
+
+ if (nh->hop_limit <= 1)
+ return -EHOSTUNREACH;
+
+ key->ip.ttl = --nh->hop_limit;
+ } else {
+ struct iphdr *nh;
+ u8 old_ttl;
+
+ err = skb_ensure_writable(skb, skb_network_offset(skb) +
+ sizeof(*nh));
+ if (unlikely(err))
+ return err;
+
+ nh = ip_hdr(skb);
+ if (nh->ttl <= 1)
+ return -EHOSTUNREACH;
+
+ old_ttl = nh->ttl--;
+ csum_replace2(&nh->check, htons(old_ttl << 8),
+ htons(nh->ttl << 8));
+ key->ip.ttl = nh->ttl;
+ }
+ return 0;
+}
+
/* Execute a list of actions against 'skb'. */
static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key,
@@ -1365,6 +1423,15 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
break;
}
+
+ case OVS_ACTION_ATTR_DEC_TTL:
+ err = execute_dec_ttl(skb, key);
+ if (err == -EHOSTUNREACH) {
+ err = dec_ttl_exception_handler(dp, skb, key,
+ a, true);
+ return err;
+ }
+ break;
}
if (unlikely(err)) {
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index 7da4230627f5..1ccd5e092bca 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -80,6 +80,7 @@ static bool actions_may_change_flow(const struct nlattr *actions)
case OVS_ACTION_ATTR_METER:
case OVS_ACTION_ATTR_CHECK_PKT_LEN:
case OVS_ACTION_ATTR_ADD_MPLS:
+ case OVS_ACTION_ATTR_DEC_TTL:
default:
return true;
}
@@ -2495,6 +2496,39 @@ static int validate_and_copy_sample(struct net *net, const struct nlattr *attr,
return 0;
}
+static int validate_and_copy_dec_ttl(struct net *net,
+ const struct nlattr *attr,
+ const struct sw_flow_key *key,
+ struct sw_flow_actions **sfa,
+ __be16 eth_type, __be16 vlan_tci,
+ u32 mpls_label_count, bool log)
+{
+ int start, err;
+ u32 nested = true;
+
+ if (!nla_len(attr))
+ return ovs_nla_add_action(sfa, OVS_ACTION_ATTR_DEC_TTL,
+ NULL, 0, log);
+
+ start = add_nested_action_start(sfa, OVS_ACTION_ATTR_DEC_TTL, log);
+ if (start < 0)
+ return start;
+
+ err = ovs_nla_add_action(sfa, OVS_DEC_TTL_ATTR_ACTION, &nested,
+ sizeof(nested), log);
+
+ if (err)
+ return err;
+
+ err = __ovs_nla_copy_actions(net, attr, key, sfa, eth_type,
+ vlan_tci, mpls_label_count, log);
+ if (err)
+ return err;
+
+ add_nested_action_end(*sfa, start);
+ return 0;
+}
+
static int validate_and_copy_clone(struct net *net,
const struct nlattr *attr,
const struct sw_flow_key *key,
@@ -3007,6 +3041,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
[OVS_ACTION_ATTR_CLONE] = (u32)-1,
[OVS_ACTION_ATTR_CHECK_PKT_LEN] = (u32)-1,
[OVS_ACTION_ATTR_ADD_MPLS] = sizeof(struct ovs_action_add_mpls),
+ [OVS_ACTION_ATTR_DEC_TTL] = (u32)-1,
};
const struct ovs_action_push_vlan *vlan;
int type = nla_type(a);
@@ -3267,6 +3302,15 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
break;
}
+ case OVS_ACTION_ATTR_DEC_TTL:
+ err = validate_and_copy_dec_ttl(net, a, key, sfa,
+ eth_type, vlan_tci,
+ mpls_label_count, log);
+ if (err)
+ return err;
+ skip_copy = true;
+ break;
+
default:
OVS_NLERR(log, "Unknown Action type %d", type);
return -EINVAL;
@@ -3438,6 +3482,26 @@ out:
return err;
}
+static int dec_ttl_action_to_attr(const struct nlattr *attr,
+ struct sk_buff *skb)
+{
+ int err = 0, rem = nla_len(attr);
+ struct nlattr *start;
+
+ start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_DEC_TTL);
+
+ if (!start)
+ return -EMSGSIZE;
+
+ err = ovs_nla_put_actions(nla_data(attr), rem, skb);
+ if (err)
+ nla_nest_cancel(skb, start);
+ else
+ nla_nest_end(skb, start);
+
+ return err;
+}
+
static int set_action_to_attr(const struct nlattr *a, struct sk_buff *skb)
{
const struct nlattr *ovs_key = nla_data(a);
@@ -3538,6 +3602,12 @@ int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
return err;
break;
+ case OVS_ACTION_ATTR_DEC_TTL:
+ err = dec_ttl_action_to_attr(a, skb);
+ if (err)
+ return err;
+ break;
+
default:
if (nla_put(skb, type, nla_len(a), nla_data(a)))
return -EMSGSIZE;