Messages in this thread Patch in this message | | | From | Matteo Croce <> | Subject | [PATCH net-next v2] openvswitch: add TTL decrement action | Date | Tue, 17 Dec 2019 16:51:02 +0100 |
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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)},1,1 in_port(1),eth(),eth_type(0x0800), packets:0, bytes:0, used:never, actions:dec_ttl{ttl<=1 action:(drop)},1,2 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-authored-by: Bindiya Kurle <bindiyakurle@gmail.com> Signed-off-by: Bindiya Kurle <bindiyakurle@gmail.com> Signed-off-by: Matteo Croce <mcroce@redhat.com> --- include/uapi/linux/openvswitch.h | 22 +++++++ net/openvswitch/actions.c | 71 +++++++++++++++++++++ net/openvswitch/flow_netlink.c | 105 +++++++++++++++++++++++++++++++ 3 files changed, 198 insertions(+)
diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index a87b44cd5590..b6684bc04883 100644 --- a/include/uapi/linux/openvswitch.h +++ b/include/uapi/linux/openvswitch.h @@ -927,6 +927,7 @@ enum ovs_action_attr { OVS_ACTION_ATTR_METER, /* u32 meter ID. */ OVS_ACTION_ATTR_CLONE, /* Nested OVS_CLONE_ATTR_*. */ OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested OVS_CHECK_PKT_LEN_ATTR_*. */ + OVS_ACTION_ATTR_DEC_TTL, /* Nested OVS_DEC_TTL_ATTR_*. */ __OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted * from userspace. */ @@ -939,6 +940,23 @@ enum ovs_action_attr { }; #define OVS_ACTION_ATTR_MAX (__OVS_ACTION_ATTR_MAX - 1) +enum ovs_dec_ttl_attr { + OVS_DEC_TTL_ATTR_UNSPEC, + OVS_DEC_TTL_ATTR_ACTION_TYPE, /* Action Type u32 */ + OVS_DEC_TTL_ATTR_ACTION, /* nested action */ + __OVS_DEC_TTL_ATTR_MAX, +#ifdef __KERNEL__ + OVS_DEC_TTL_ATTR_ARG /* struct sample_arg */ +#endif +}; + +#ifdef __KERNEL__ +struct dec_ttl_arg { + u32 action_type; /* dec_ttl action type.*/ +}; +#endif + +#define OVS_DEC_TTL_ATTR_MAX (__OVS_DEC_TTL_ATTR_MAX - 1) /* Meters. */ #define OVS_METER_FAMILY "ovs_meter" @@ -1009,6 +1027,10 @@ enum ovs_ct_limit_attr { __OVS_CT_LIMIT_ATTR_MAX }; +enum ovs_dec_ttl_action { /*Actions supported by dec_ttl */ + OVS_DEC_TTL_ACTION_DROP, + OVS_DEC_TTL_ACTION_USER_SPACE +}; #define OVS_CT_LIMIT_ATTR_MAX (__OVS_CT_LIMIT_ATTR_MAX - 1) #define OVS_ZONE_LIMIT_DEFAULT_ZONE -1 diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 4c8395462303..5329668732b1 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -960,6 +960,31 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb, return ovs_dp_upcall(dp, skb, key, &upcall, cutlen); } +static int dec_ttl(struct datapath *dp, struct sk_buff *skb, + struct sw_flow_key *fk, const struct nlattr *attr, bool last) +{ + struct nlattr *actions; + struct nlattr *dec_ttl_arg; + int rem = nla_len(attr); + const struct dec_ttl_arg *arg; + + /* The first action is always OVS_DEC_TTL_ATTR_ARG. */ + dec_ttl_arg = nla_data(attr); + arg = nla_data(dec_ttl_arg); + actions = nla_next(dec_ttl_arg, &rem); + + switch (arg->action_type) { + case OVS_DEC_TTL_ACTION_DROP: + consume_skb(skb); + break; + + case OVS_DEC_TTL_ACTION_USER_SPACE: + return clone_execute(dp, skb, fk, 0, actions, rem, last, false); + } + + 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(). @@ -1176,6 +1201,44 @@ 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 = ipv6_hdr(skb); + + err = skb_ensure_writable(skb, skb_network_offset(skb) + + sizeof(*nh)); + if (unlikely(err)) + return err; + + if (nh->hop_limit <= 1) + return -EHOSTUNREACH; + + key->ip.ttl = --nh->hop_limit; + } else { + struct iphdr *nh = ip_hdr(skb); + 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, @@ -1347,6 +1410,14 @@ 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(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 65c2e3458ff5..a9eea2ffb8b0 100644 --- a/net/openvswitch/flow_netlink.c +++ b/net/openvswitch/flow_netlink.c @@ -61,6 +61,7 @@ static bool actions_may_change_flow(const struct nlattr *actions) case OVS_ACTION_ATTR_RECIRC: case OVS_ACTION_ATTR_TRUNC: case OVS_ACTION_ATTR_USERSPACE: + case OVS_ACTION_ATTR_DEC_TTL: break; case OVS_ACTION_ATTR_CT: @@ -2494,6 +2495,59 @@ 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) +{ + struct nlattr *attrs[OVS_DEC_TTL_ATTR_MAX + 1] = { 0 }; + const struct nlattr *action_type, *action; + struct nlattr *a; + int rem, start, err; + struct dec_ttl_arg arg; + + nla_for_each_nested(a, attr, rem) { + int type = nla_type(a); + + if (!type || type > OVS_DEC_TTL_ATTR_MAX || attrs[type]) + return -EINVAL; + + attrs[type] = a; + } + if (rem) + return -EINVAL; + + action_type = attrs[OVS_DEC_TTL_ATTR_ACTION_TYPE]; + if (!action_type || nla_len(action_type) != sizeof(u32)) + return -EINVAL; + + start = add_nested_action_start(sfa, OVS_ACTION_ATTR_DEC_TTL, log); + if (start < 0) + return start; + + arg.action_type = nla_get_u32(action_type); + err = ovs_nla_add_action(sfa, OVS_DEC_TTL_ATTR_ARG, + &arg, sizeof(arg), log); + if (err) + return err; + + if (arg.action_type == OVS_DEC_TTL_ACTION_USER_SPACE) { + action = attrs[OVS_DEC_TTL_ATTR_ACTION]; + if (!action || (nla_len(action) && nla_len(action) < NLA_HDRLEN)) + return -EINVAL; + + err = __ovs_nla_copy_actions(net, action, 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, @@ -3005,6 +3059,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr, [OVS_ACTION_ATTR_METER] = sizeof(u32), [OVS_ACTION_ATTR_CLONE] = (u32)-1, [OVS_ACTION_ATTR_CHECK_PKT_LEN] = (u32)-1, + [OVS_ACTION_ATTR_DEC_TTL] = (u32)-1, }; const struct ovs_action_push_vlan *vlan; int type = nla_type(a); @@ -3233,6 +3288,15 @@ 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; @@ -3404,6 +3468,41 @@ static int check_pkt_len_action_to_attr(const struct nlattr *attr, return err; } +static int dec_ttl_action_to_attr(const struct nlattr *att, struct sk_buff *skb) +{ + struct nlattr *start, *ac_start = NULL, *dec_ttl; + int err = 0, rem = nla_len(att); + const struct dec_ttl_arg *arg; + struct nlattr *actions; + + start = nla_nest_start_noflag(skb, OVS_ACTION_ATTR_DEC_TTL); + if (!start) + return -EMSGSIZE; + + dec_ttl = nla_data(att); + arg = nla_data(dec_ttl); + actions = nla_next(dec_ttl, &rem); + + if (nla_put_u32(skb, OVS_DEC_TTL_ATTR_ACTION_TYPE, arg->action_type)) { + nla_nest_cancel(skb, start); + return -EMSGSIZE; + } + + if (arg->action_type == OVS_DEC_TTL_ACTION_USER_SPACE) { + ac_start = nla_nest_start_noflag(skb, OVS_DEC_TTL_ATTR_ACTION); + if (!ac_start) { + nla_nest_cancel(skb, ac_start); + nla_nest_cancel(skb, start); + return -EMSGSIZE; + } + err = ovs_nla_put_actions(actions, rem, skb); + nla_nest_end(skb, ac_start); + } + 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); @@ -3504,6 +3603,12 @@ 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; -- 2.23.0
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