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![Tonghao Zhang](/assets/img/avatar_default.png)
When using the kernel datapath, the upcall don't include skb hash info relatived. That will introduce some problem, because the hash of skb is important in kernel stack. For example, VXLAN module uses it to select UDP src port. The tx queue selection may also use the hash in stack. Hash is computed in different ways. Hash is random for a TCP socket, and hash may be computed in hardware, or software stack. Recalculation hash is not easy. Hash of TCP socket is computed: tcp_v4_connect -> sk_set_txhash (is random) __tcp_transmit_skb -> skb_set_hash_from_sk There will be one upcall, without information of skb hash, to ovs-vswitchd, for the first packet of a TCP session. The rest packets will be processed in Open vSwitch modules, hash kept. If this tcp session is forward to VXLAN module, then the UDP src port of first tcp packet is different from rest packets. TCP packets may come from the host or dockers, to Open vSwitch. To fix it, we store the hash info to upcall, and restore hash when packets sent back. +---------------+ +-------------------------+ | Docker/VMs | | ovs-vswitchd | +----+----------+ +-+--------------------+--+ | ^ | | | | | | upcall v restore packet hash (not recalculate) | +-+--------------------+--+ | tap netdev | | vxlan module +---------------> +--> Open vSwitch ko +--> or internal type | | +-------------------------+ Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2019-October/364062.html Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
262 lines
7.3 KiB
C
262 lines
7.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (c) 2007-2014 Nicira, Inc.
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*/
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#ifndef DATAPATH_H
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#define DATAPATH_H 1
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#include <asm/page.h>
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#include <linux/kernel.h>
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#include <linux/mutex.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/u64_stats_sync.h>
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#include <net/ip_tunnels.h>
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#include "conntrack.h"
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#include "flow.h"
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#include "flow_table.h"
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#include "meter.h"
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#include "vport-internal_dev.h"
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#define DP_MAX_PORTS USHRT_MAX
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#define DP_VPORT_HASH_BUCKETS 1024
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/**
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* struct dp_stats_percpu - per-cpu packet processing statistics for a given
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* datapath.
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* @n_hit: Number of received packets for which a matching flow was found in
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* the flow table.
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* @n_miss: Number of received packets that had no matching flow in the flow
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* table. The sum of @n_hit and @n_miss is the number of packets that have
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* been received by the datapath.
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* @n_lost: Number of received packets that had no matching flow in the flow
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* table that could not be sent to userspace (normally due to an overflow in
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* one of the datapath's queues).
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* @n_mask_hit: Number of masks looked up for flow match.
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* @n_mask_hit / (@n_hit + @n_missed) will be the average masks looked
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* up per packet.
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*/
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struct dp_stats_percpu {
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u64 n_hit;
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u64 n_missed;
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u64 n_lost;
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u64 n_mask_hit;
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struct u64_stats_sync syncp;
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};
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/**
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* struct datapath - datapath for flow-based packet switching
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* @rcu: RCU callback head for deferred destruction.
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* @list_node: Element in global 'dps' list.
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* @table: flow table.
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* @ports: Hash table for ports. %OVSP_LOCAL port always exists. Protected by
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* ovs_mutex and RCU.
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* @stats_percpu: Per-CPU datapath statistics.
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* @net: Reference to net namespace.
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* @max_headroom: the maximum headroom of all vports in this datapath; it will
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* be used by all the internal vports in this dp.
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*
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* Context: See the comment on locking at the top of datapath.c for additional
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* locking information.
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*/
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struct datapath {
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struct rcu_head rcu;
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struct list_head list_node;
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/* Flow table. */
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struct flow_table table;
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/* Switch ports. */
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struct hlist_head *ports;
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/* Stats. */
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struct dp_stats_percpu __percpu *stats_percpu;
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/* Network namespace ref. */
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possible_net_t net;
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u32 user_features;
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u32 max_headroom;
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/* Switch meters. */
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struct hlist_head *meters;
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};
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/**
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* struct ovs_skb_cb - OVS data in skb CB
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* @input_vport: The original vport packet came in on. This value is cached
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* when a packet is received by OVS.
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* @mru: The maximum received fragement size; 0 if the packet is not
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* fragmented.
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* @acts_origlen: The netlink size of the flow actions applied to this skb.
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* @cutlen: The number of bytes from the packet end to be removed.
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*/
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struct ovs_skb_cb {
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struct vport *input_vport;
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u16 mru;
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u16 acts_origlen;
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u32 cutlen;
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};
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#define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb)
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/**
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* struct dp_upcall - metadata to include with a packet to send to userspace
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* @cmd: One of %OVS_PACKET_CMD_*.
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* @userdata: If nonnull, its variable-length value is passed to userspace as
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* %OVS_PACKET_ATTR_USERDATA.
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* @portid: Netlink portid to which packet should be sent. If @portid is 0
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* then no packet is sent and the packet is accounted in the datapath's @n_lost
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* counter.
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* @egress_tun_info: If nonnull, becomes %OVS_PACKET_ATTR_EGRESS_TUN_KEY.
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* @mru: If not zero, Maximum received IP fragment size.
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*/
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struct dp_upcall_info {
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struct ip_tunnel_info *egress_tun_info;
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const struct nlattr *userdata;
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const struct nlattr *actions;
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int actions_len;
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u32 portid;
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u8 cmd;
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u16 mru;
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};
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/**
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* struct ovs_net - Per net-namespace data for ovs.
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* @dps: List of datapaths to enable dumping them all out.
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* Protected by genl_mutex.
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*/
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struct ovs_net {
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struct list_head dps;
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struct work_struct dp_notify_work;
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#if IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
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struct ovs_ct_limit_info *ct_limit_info;
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#endif
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/* Module reference for configuring conntrack. */
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bool xt_label;
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};
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/**
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* enum ovs_pkt_hash_types - hash info to include with a packet
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* to send to userspace.
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* @OVS_PACKET_HASH_SW_BIT: indicates hash was computed in software stack.
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* @OVS_PACKET_HASH_L4_BIT: indicates hash is a canonical 4-tuple hash
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* over transport ports.
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*/
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enum ovs_pkt_hash_types {
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OVS_PACKET_HASH_SW_BIT = (1ULL << 32),
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OVS_PACKET_HASH_L4_BIT = (1ULL << 33),
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};
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extern unsigned int ovs_net_id;
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void ovs_lock(void);
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void ovs_unlock(void);
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#ifdef CONFIG_LOCKDEP
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int lockdep_ovsl_is_held(void);
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#else
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#define lockdep_ovsl_is_held() 1
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#endif
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#define ASSERT_OVSL() WARN_ON(!lockdep_ovsl_is_held())
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#define ovsl_dereference(p) \
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rcu_dereference_protected(p, lockdep_ovsl_is_held())
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#define rcu_dereference_ovsl(p) \
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rcu_dereference_check(p, lockdep_ovsl_is_held())
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static inline struct net *ovs_dp_get_net(const struct datapath *dp)
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{
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return read_pnet(&dp->net);
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}
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static inline void ovs_dp_set_net(struct datapath *dp, struct net *net)
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{
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write_pnet(&dp->net, net);
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}
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struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no);
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static inline struct vport *ovs_vport_rcu(const struct datapath *dp, int port_no)
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{
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WARN_ON_ONCE(!rcu_read_lock_held());
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return ovs_lookup_vport(dp, port_no);
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}
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static inline struct vport *ovs_vport_ovsl_rcu(const struct datapath *dp, int port_no)
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{
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WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
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return ovs_lookup_vport(dp, port_no);
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}
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static inline struct vport *ovs_vport_ovsl(const struct datapath *dp, int port_no)
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{
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ASSERT_OVSL();
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return ovs_lookup_vport(dp, port_no);
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}
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/* Must be called with rcu_read_lock. */
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static inline struct datapath *get_dp_rcu(struct net *net, int dp_ifindex)
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{
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struct net_device *dev = dev_get_by_index_rcu(net, dp_ifindex);
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if (dev) {
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struct vport *vport = ovs_internal_dev_get_vport(dev);
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if (vport)
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return vport->dp;
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}
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return NULL;
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}
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/* The caller must hold either ovs_mutex or rcu_read_lock to keep the
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* returned dp pointer valid.
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*/
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static inline struct datapath *get_dp(struct net *net, int dp_ifindex)
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{
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struct datapath *dp;
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WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
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rcu_read_lock();
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dp = get_dp_rcu(net, dp_ifindex);
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rcu_read_unlock();
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return dp;
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}
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extern struct notifier_block ovs_dp_device_notifier;
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extern struct genl_family dp_vport_genl_family;
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DECLARE_STATIC_KEY_FALSE(tc_recirc_sharing_support);
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void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key);
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void ovs_dp_detach_port(struct vport *);
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int ovs_dp_upcall(struct datapath *, struct sk_buff *,
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const struct sw_flow_key *, const struct dp_upcall_info *,
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uint32_t cutlen);
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const char *ovs_dp_name(const struct datapath *dp);
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struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, struct net *net,
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u32 portid, u32 seq, u8 cmd);
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int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
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const struct sw_flow_actions *, struct sw_flow_key *);
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void ovs_dp_notify_wq(struct work_struct *work);
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int action_fifos_init(void);
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void action_fifos_exit(void);
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/* 'KEY' must not have any bits set outside of the 'MASK' */
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#define OVS_MASKED(OLD, KEY, MASK) ((KEY) | ((OLD) & ~(MASK)))
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#define OVS_SET_MASKED(OLD, KEY, MASK) ((OLD) = OVS_MASKED(OLD, KEY, MASK))
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#define OVS_NLERR(logging_allowed, fmt, ...) \
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do { \
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if (logging_allowed && net_ratelimit()) \
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pr_info("netlink: " fmt "\n", ##__VA_ARGS__); \
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} while (0)
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#endif /* datapath.h */
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