From f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 Mon Sep 17 00:00:00 2001 From: William Tu Date: Fri, 10 Jun 2016 11:49:33 -0700 Subject: [PATCH] openvswitch: Add packet truncation support. The patch adds a new OVS action, OVS_ACTION_ATTR_TRUNC, in order to truncate packets. A 'max_len' is added for setting up the maximum packet size, and a 'cutlen' field is to record the number of bytes to trim the packet when the packet is outputting to a port, or when the packet is sent to userspace. Signed-off-by: William Tu Cc: Pravin Shelar Acked-by: Pravin B Shelar Signed-off-by: David S. Miller --- include/uapi/linux/openvswitch.h | 6 +++++ net/openvswitch/actions.c | 40 ++++++++++++++++++++++++++++---- net/openvswitch/datapath.c | 29 +++++++++++++---------- net/openvswitch/datapath.h | 5 +++- net/openvswitch/flow_netlink.c | 9 +++++++ net/openvswitch/vport.c | 1 + 6 files changed, 73 insertions(+), 17 deletions(-) diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h index bb0d515b7654..8274675ba9a3 100644 --- a/include/uapi/linux/openvswitch.h +++ b/include/uapi/linux/openvswitch.h @@ -580,6 +580,10 @@ enum ovs_userspace_attr { #define OVS_USERSPACE_ATTR_MAX (__OVS_USERSPACE_ATTR_MAX - 1) +struct ovs_action_trunc { + uint32_t max_len; /* Max packet size in bytes. */ +}; + /** * struct ovs_action_push_mpls - %OVS_ACTION_ATTR_PUSH_MPLS action argument. * @mpls_lse: MPLS label stack entry to push. @@ -703,6 +707,7 @@ enum ovs_nat_attr { * enum ovs_action_attr - Action types. * * @OVS_ACTION_ATTR_OUTPUT: Output packet to port. + * @OVS_ACTION_ATTR_TRUNC: Output packet to port with truncated packet size. * @OVS_ACTION_ATTR_USERSPACE: Send packet to userspace according to nested * %OVS_USERSPACE_ATTR_* attributes. * @OVS_ACTION_ATTR_SET: Replaces the contents of an existing header. The @@ -756,6 +761,7 @@ enum ovs_action_attr { * The data must be zero for the unmasked * bits. */ OVS_ACTION_ATTR_CT, /* Nested OVS_CT_ATTR_* . */ + OVS_ACTION_ATTR_TRUNC, /* u32 struct ovs_action_trunc. */ __OVS_ACTION_ATTR_MAX, /* Nothing past this will be accepted * from userspace. */ diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index 9a3eb7a0ebf4..1ecbd7715f6d 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -750,6 +750,14 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port, if (likely(vport)) { u16 mru = OVS_CB(skb)->mru; + u32 cutlen = OVS_CB(skb)->cutlen; + + if (unlikely(cutlen > 0)) { + if (skb->len - cutlen > ETH_HLEN) + pskb_trim(skb, skb->len - cutlen); + else + pskb_trim(skb, ETH_HLEN); + } if (likely(!mru || (skb->len <= mru + ETH_HLEN))) { ovs_vport_send(vport, skb); @@ -775,7 +783,8 @@ static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port, static int output_userspace(struct datapath *dp, struct sk_buff *skb, struct sw_flow_key *key, const struct nlattr *attr, - const struct nlattr *actions, int actions_len) + const struct nlattr *actions, int actions_len, + uint32_t cutlen) { struct dp_upcall_info upcall; const struct nlattr *a; @@ -822,7 +831,7 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb, } /* End of switch. */ } - return ovs_dp_upcall(dp, skb, key, &upcall); + return ovs_dp_upcall(dp, skb, key, &upcall, cutlen); } static int sample(struct datapath *dp, struct sk_buff *skb, @@ -832,6 +841,7 @@ static int sample(struct datapath *dp, struct sk_buff *skb, const struct nlattr *acts_list = NULL; const struct nlattr *a; int rem; + u32 cutlen = 0; for (a = nla_data(attr), rem = nla_len(attr); rem > 0; a = nla_next(a, &rem)) { @@ -858,13 +868,24 @@ static int sample(struct datapath *dp, struct sk_buff *skb, return 0; /* The only known usage of sample action is having a single user-space + * action, or having a truncate action followed by a single user-space * action. Treat this usage as a special case. * The output_userspace() should clone the skb to be sent to the * user space. This skb will be consumed by its caller. */ + if (unlikely(nla_type(a) == OVS_ACTION_ATTR_TRUNC)) { + struct ovs_action_trunc *trunc = nla_data(a); + + if (skb->len > trunc->max_len) + cutlen = skb->len - trunc->max_len; + + a = nla_next(a, &rem); + } + if (likely(nla_type(a) == OVS_ACTION_ATTR_USERSPACE && nla_is_last(a, rem))) - return output_userspace(dp, skb, key, a, actions, actions_len); + return output_userspace(dp, skb, key, a, actions, + actions_len, cutlen); skb = skb_clone(skb, GFP_ATOMIC); if (!skb) @@ -1051,6 +1072,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, if (out_skb) do_output(dp, out_skb, prev_port, key); + OVS_CB(skb)->cutlen = 0; prev_port = -1; } @@ -1059,8 +1081,18 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, prev_port = nla_get_u32(a); break; + case OVS_ACTION_ATTR_TRUNC: { + struct ovs_action_trunc *trunc = nla_data(a); + + if (skb->len > trunc->max_len) + OVS_CB(skb)->cutlen = skb->len - trunc->max_len; + break; + } + case OVS_ACTION_ATTR_USERSPACE: - output_userspace(dp, skb, key, a, attr, len); + output_userspace(dp, skb, key, a, attr, + len, OVS_CB(skb)->cutlen); + OVS_CB(skb)->cutlen = 0; break; case OVS_ACTION_ATTR_HASH: diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 856bd8dba676..673934295333 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -137,10 +137,12 @@ EXPORT_SYMBOL_GPL(lockdep_ovsl_is_held); static struct vport *new_vport(const struct vport_parms *); static int queue_gso_packets(struct datapath *dp, struct sk_buff *, const struct sw_flow_key *, - const struct dp_upcall_info *); + const struct dp_upcall_info *, + uint32_t cutlen); static int queue_userspace_packet(struct datapath *dp, struct sk_buff *, const struct sw_flow_key *, - const struct dp_upcall_info *); + const struct dp_upcall_info *, + uint32_t cutlen); /* Must be called with rcu_read_lock. */ static struct datapath *get_dp_rcu(struct net *net, int dp_ifindex) @@ -275,7 +277,7 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key) upcall.cmd = OVS_PACKET_CMD_MISS; upcall.portid = ovs_vport_find_upcall_portid(p, skb); upcall.mru = OVS_CB(skb)->mru; - error = ovs_dp_upcall(dp, skb, key, &upcall); + error = ovs_dp_upcall(dp, skb, key, &upcall, 0); if (unlikely(error)) kfree_skb(skb); else @@ -300,7 +302,8 @@ out: int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb, const struct sw_flow_key *key, - const struct dp_upcall_info *upcall_info) + const struct dp_upcall_info *upcall_info, + uint32_t cutlen) { struct dp_stats_percpu *stats; int err; @@ -311,9 +314,9 @@ int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb, } if (!skb_is_gso(skb)) - err = queue_userspace_packet(dp, skb, key, upcall_info); + err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen); else - err = queue_gso_packets(dp, skb, key, upcall_info); + err = queue_gso_packets(dp, skb, key, upcall_info, cutlen); if (err) goto err; @@ -331,7 +334,8 @@ err: static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb, const struct sw_flow_key *key, - const struct dp_upcall_info *upcall_info) + const struct dp_upcall_info *upcall_info, + uint32_t cutlen) { unsigned short gso_type = skb_shinfo(skb)->gso_type; struct sw_flow_key later_key; @@ -360,7 +364,7 @@ static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb, if (gso_type & SKB_GSO_UDP && skb != segs) key = &later_key; - err = queue_userspace_packet(dp, skb, key, upcall_info); + err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen); if (err) break; @@ -416,7 +420,8 @@ static void pad_packet(struct datapath *dp, struct sk_buff *skb) static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, const struct sw_flow_key *key, - const struct dp_upcall_info *upcall_info) + const struct dp_upcall_info *upcall_info, + uint32_t cutlen) { struct ovs_header *upcall; struct sk_buff *nskb = NULL; @@ -461,7 +466,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, else hlen = skb->len; - len = upcall_msg_size(upcall_info, hlen); + len = upcall_msg_size(upcall_info, hlen - cutlen); user_skb = genlmsg_new(len, GFP_ATOMIC); if (!user_skb) { err = -ENOMEM; @@ -515,9 +520,9 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, err = -ENOBUFS; goto out; } - nla->nla_len = nla_attr_size(skb->len); + nla->nla_len = nla_attr_size(skb->len - cutlen); - err = skb_zerocopy(user_skb, skb, skb->len, hlen); + err = skb_zerocopy(user_skb, skb, skb->len - cutlen, hlen); if (err) goto out; diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h index 427e39a045cf..ab85c1cae255 100644 --- a/net/openvswitch/datapath.h +++ b/net/openvswitch/datapath.h @@ -100,11 +100,13 @@ struct datapath { * @input_vport: The original vport packet came in on. This value is cached * when a packet is received by OVS. * @mru: The maximum received fragement size; 0 if the packet is not + * @cutlen: The number of bytes from the packet end to be removed. * fragmented. */ struct ovs_skb_cb { struct vport *input_vport; u16 mru; + u32 cutlen; }; #define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb) @@ -194,7 +196,8 @@ extern struct genl_family dp_vport_genl_family; void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key); void ovs_dp_detach_port(struct vport *); int ovs_dp_upcall(struct datapath *, struct sk_buff *, - const struct sw_flow_key *, const struct dp_upcall_info *); + const struct sw_flow_key *, const struct dp_upcall_info *, + uint32_t cutlen); const char *ovs_dp_name(const struct datapath *dp); struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 pid, u32 seq, diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c index 0bb650f4f219..c78a6a1476fb 100644 --- a/net/openvswitch/flow_netlink.c +++ b/net/openvswitch/flow_netlink.c @@ -2229,6 +2229,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr, [OVS_ACTION_ATTR_SAMPLE] = (u32)-1, [OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash), [OVS_ACTION_ATTR_CT] = (u32)-1, + [OVS_ACTION_ATTR_TRUNC] = sizeof(struct ovs_action_trunc), }; const struct ovs_action_push_vlan *vlan; int type = nla_type(a); @@ -2255,6 +2256,14 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr, return -EINVAL; break; + case OVS_ACTION_ATTR_TRUNC: { + const struct ovs_action_trunc *trunc = nla_data(a); + + if (trunc->max_len < ETH_HLEN) + return -EINVAL; + break; + } + case OVS_ACTION_ATTR_HASH: { const struct ovs_action_hash *act_hash = nla_data(a); diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c index 31cbc8c5c7db..6b21fd068d87 100644 --- a/net/openvswitch/vport.c +++ b/net/openvswitch/vport.c @@ -444,6 +444,7 @@ int ovs_vport_receive(struct vport *vport, struct sk_buff *skb, OVS_CB(skb)->input_vport = vport; OVS_CB(skb)->mru = 0; + OVS_CB(skb)->cutlen = 0; if (unlikely(dev_net(skb->dev) != ovs_dp_get_net(vport->dp))) { u32 mark; -- 2.20.1