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[149.6.153.186]) by smtp.gmail.com with ESMTPSA id x5sm2290277wmj.7.2019.11.12.02.25.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Nov 2019 02:25:21 -0800 (PST) From: Matteo Croce To: netdev@vger.kernel.org, dev@openvswitch.org Cc: linux-kernel@vger.kernel.org, Pravin B Shelar , "David S. Miller" , Bindiya Kurle Subject: [PATCH net-next] openvswitch: add TTL decrement action Date: Tue, 12 Nov 2019 11:25:18 +0100 Message-Id: <20191112102518.4406-1-mcroce@redhat.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 X-MC-Unique: g_h4dZ5zPmKHvtgE92CvGQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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, send the packet to userspace via output_userspace() to take care of it. 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, acti= ons:dec_ttl,1 in_port(1),eth(),eth_type(0x0800), packets:0, bytes:0, used:never, acti= ons:dec_ttl,2 in_port(1),eth(),eth_type(0x0806), packets:0, bytes:0, used:never, acti= ons:2 in_port(2),eth(),eth_type(0x0806), packets:0, bytes:0, used:never, acti= ons:1 # ping -c1 192.168.0.2 -t 42 IP (tos 0x0, ttl 41, id 61647, offset 0, flags [DF], proto ICMP (1), le= ngth 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), l= ength 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 Signed-off-by: Bindiya Kurle Signed-off-by: Matteo Croce --- include/uapi/linux/openvswitch.h | 2 ++ net/openvswitch/actions.c | 46 ++++++++++++++++++++++++++++++++ net/openvswitch/flow_netlink.c | 6 +++++ 3 files changed, 54 insertions(+) diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswi= tch.h index 1887a451c388..a3bdb1ecd1e7 100644 --- a/include/uapi/linux/openvswitch.h +++ b/include/uapi/linux/openvswitch.h @@ -890,6 +890,7 @@ struct check_pkt_len_arg { * @OVS_ACTION_ATTR_CHECK_PKT_LEN: Check the packet length and execute a s= et * of actions if greater than the specified packet length, else execute * another set of actions. + * @OVS_ACTION_ATTR_DEC_TTL: Decrement the IP TTL. * * Only a single header can be set with a single %OVS_ACTION_ATTR_SET. No= t all * fields within a header are modifiable, e.g. the IPv4 protocol and fragm= ent @@ -925,6 +926,7 @@ enum ovs_action_attr { =09OVS_ACTION_ATTR_METER, /* u32 meter ID. */ =09OVS_ACTION_ATTR_CLONE, /* Nested OVS_CLONE_ATTR_*. */ =09OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested OVS_CHECK_PKT_LEN_ATTR_*. */ +=09OVS_ACTION_ATTR_DEC_TTL, /* Decrement ttl action */ =20 =09__OVS_ACTION_ATTR_MAX,=09 /* Nothing past this will be accepted =09=09=09=09 * from userspace. */ diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 12936c151cc0..077b7f309c93 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -1174,6 +1174,43 @@ static int execute_check_pkt_len(struct datapath *dp= , struct sk_buff *skb, =09=09=09 nla_len(actions), last, clone_flow_key); } =20 +static int execute_dec_ttl(struct sk_buff *skb, struct sw_flow_key *key) +{ +=09int err; + +=09if (skb->protocol =3D=3D htons(ETH_P_IPV6)) { +=09=09struct ipv6hdr *nh =3D ipv6_hdr(skb); + +=09=09err =3D skb_ensure_writable(skb, skb_network_offset(skb) + +=09=09=09=09=09 sizeof(*nh)); +=09=09if (unlikely(err)) +=09=09=09return err; + +=09=09if (nh->hop_limit <=3D 1) +=09=09=09return -EHOSTUNREACH; + +=09=09key->ip.ttl =3D --nh->hop_limit; +=09} else { +=09=09struct iphdr *nh =3D ip_hdr(skb); +=09=09u8 old_ttl; + +=09=09err =3D skb_ensure_writable(skb, skb_network_offset(skb) + +=09=09=09=09=09 sizeof(*nh)); +=09=09if (unlikely(err)) +=09=09=09return err; + +=09=09if (nh->ttl <=3D 1) +=09=09=09return -EHOSTUNREACH; + +=09=09old_ttl =3D nh->ttl--; +=09=09csum_replace2(&nh->check, htons(old_ttl << 8), +=09=09=09 htons(nh->ttl << 8)); +=09=09key->ip.ttl =3D nh->ttl; +=09} + +=09return 0; +} + /* Execute a list of actions against 'skb'. */ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, =09=09=09 struct sw_flow_key *key, @@ -1345,6 +1382,15 @@ static int do_execute_actions(struct datapath *dp, s= truct sk_buff *skb, =20 =09=09=09break; =09=09} + +=09=09case OVS_ACTION_ATTR_DEC_TTL: +=09=09=09err =3D execute_dec_ttl(skb, key); +=09=09=09if (err =3D=3D -EHOSTUNREACH) { +=09=09=09=09output_userspace(dp, skb, key, a, attr, +=09=09=09=09=09=09 len, OVS_CB(skb)->cutlen); +=09=09=09=09OVS_CB(skb)->cutlen =3D 0; +=09=09=09} +=09=09=09break; =09=09} =20 =09=09if (unlikely(err)) { diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.= c index 65c2e3458ff5..d17f2d4b420f 100644 --- a/net/openvswitch/flow_netlink.c +++ b/net/openvswitch/flow_netlink.c @@ -79,6 +79,7 @@ static bool actions_may_change_flow(const struct nlattr *= actions) =09=09case OVS_ACTION_ATTR_SET_MASKED: =09=09case OVS_ACTION_ATTR_METER: =09=09case OVS_ACTION_ATTR_CHECK_PKT_LEN: +=09=09case OVS_ACTION_ATTR_DEC_TTL: =09=09default: =09=09=09return true; =09=09} @@ -3005,6 +3006,7 @@ static int __ovs_nla_copy_actions(struct net *net, co= nst struct nlattr *attr, =09=09=09[OVS_ACTION_ATTR_METER] =3D sizeof(u32), =09=09=09[OVS_ACTION_ATTR_CLONE] =3D (u32)-1, =09=09=09[OVS_ACTION_ATTR_CHECK_PKT_LEN] =3D (u32)-1, +=09=09=09[OVS_ACTION_ATTR_DEC_TTL] =3D 0, =09=09}; =09=09const struct ovs_action_push_vlan *vlan; =09=09int type =3D nla_type(a); @@ -3233,6 +3235,10 @@ static int __ovs_nla_copy_actions(struct net *net, c= onst struct nlattr *attr, =09=09=09break; =09=09} =20 +=09=09case OVS_ACTION_ATTR_DEC_TTL: +=09=09=09/* Nothing to do. */ +=09=09=09break; + =09=09default: =09=09=09OVS_NLERR(log, "Unknown Action type %d", type); =09=09=09return -EINVAL; --=20 2.23.0