[ovs-dev] [PATCH 1/2] datapath: Add support for tun_key to Open vSwitch datapath

Pravin Shelar pshelar at nicira.com
Thu Oct 11 21:32:59 UTC 2012


On Thu, Oct 11, 2012 at 1:52 PM, Kyle Mestery (kmestery)
<kmestery at cisco.com> wrote:
>
> On Oct 10, 2012, at 6:23 PM, Pravin Shelar <pshelar at nicira.com> wrote:
>
>> Patch looks good, I have few comments inlined.
>>
>>
>> On Tue, Oct 9, 2012 at 11:49 AM, Kyle Mestery <kmestery at cisco.com> wrote:
>>> This is a first pass at providing a tun_key which can be
>>> used as the basis for flow-based tunnelling. The
>>> tun_key includes and replaces the tun_id in both struct
>>> ovs_skb_cb and struct sw_tun_key.
>>>
>>> This patch allows all existing tun_id behaviour to still work. Existing
>>> users of tun_id are redirected to tun_key->tun_id to retain compatibility.
>>> However, when the userspace code is updated to make use of the new tun_key,
>>> the old behaviour will be deprecated and removed.
>>>
>>> NOTE: With these changes, the tunneling code no longer assumes input and
>>> output keys are symmetric.  If they are not, PMTUD needs to be disabled
>>> for tunneling to work.
>>>
>>> Signed-off-by: Kyle Mestery <kmestery at cisco.com>
>>> Cc: Simon Horman <horms at verge.net.au>
>>> Cc: Jesse Gross <jesse at nicira.com>
>>> ---
>>> V6:
>>> - Fix more comments addressed from Jesse.
>>> V5:
>>> - Address another round of comments from Jesse.
>>> V4:
>>> - Address 2 comments from Jesse:
>>>  - When processing actions, if OVS_CB(skb)->tun_key is NULL, point it at one
>>>    on the stack temporarily. This goes away when we remove the ability to set
>>>    tun_id outside the scope of tun_key.
>>>  - Move tun_key to the end of struct sw_flow_key.
>>> V3:
>>> - Fix issues found during review by Jesse.
>>> - Add a NEWS entry around tunnel code no longer assuming symmetric input and
>>>  output tunnel keys.
>>>
>>> V2:
>>> - Fix blank line addition/removal found by Simon.
>>> - Fix hex printing output found by Simon.
>>> ---
>>> NEWS                        |   3 ++
>>> datapath/actions.c          |  38 +++++++++++++----
>>> datapath/datapath.c         |  10 ++++-
>>> datapath/datapath.h         |   5 ++-
>>> datapath/flow.c             |  64 ++++++++++++++++++++++++----
>>> datapath/flow.h             |  12 ++++--
>>> datapath/tunnel.c           | 101 ++++++++++++++++++++++++++++----------------
>>> datapath/tunnel.h           |  15 ++++++-
>>> datapath/vport-capwap.c     |  12 +++---
>>> datapath/vport-gre.c        |  15 ++++---
>>> datapath/vport.c            |   2 +-
>>> include/linux/openvswitch.h |  18 +++++++-
>>> lib/dpif-netdev.c           |   1 +
>>> lib/odp-util.c              |  15 ++++++-
>>> lib/odp-util.h              |   3 +-
>>> 15 files changed, 235 insertions(+), 79 deletions(-)
>>>
>>> diff --git a/NEWS b/NEWS
>>> index 29fd9f3..ae831e3 100644
>>> --- a/NEWS
>>> +++ b/NEWS
>>> @@ -1,5 +1,8 @@
>>> post-v1.8.0
>>> ------------------------
>>> +    - The tunneling code no longer assumes input and output keys are symmetric.
>>> +      If they are not, PMTUD needs to be disabled for tunneling to work. Note
>>> +      this only applies to flow-based keys.
>>>     - FreeBSD is now a supported platform, thanks to code contributions from
>>>       Gaetano Catalli, Ed Maste, and Giuseppe Lettieri.
>>>     - ovs-bugtool: New --ovs option to report only OVS related information.
>>> diff --git a/datapath/actions.c b/datapath/actions.c
>>> index ec9b595..fa8c10d 100644
>>> --- a/datapath/actions.c
>>> +++ b/datapath/actions.c
>>> @@ -37,7 +37,8 @@
>>> #include "vport.h"
>>>
>>> static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>>> -                       const struct nlattr *attr, int len, bool keep_skb);
>>> +                       const struct nlattr *attr, int len,
>>> +                       struct ovs_key_ipv4_tunnel *tun_key, bool keep_skb);
>>>
>>> static int make_writable(struct sk_buff *skb, int write_len)
>>> {
>>> @@ -329,11 +330,14 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
>>>        }
>>>
>>>        return do_execute_actions(dp, skb, nla_data(acts_list),
>>> -                                                nla_len(acts_list), true);
>>> +                                                nla_len(acts_list),
>>> +                                                OVS_CB(skb)->tun_key,
>>> +                                                true);
>>> }
>>>
>>> static int execute_set_action(struct sk_buff *skb,
>>> -                                const struct nlattr *nested_attr)
>>> +                                const struct nlattr *nested_attr,
>>> +                                struct ovs_key_ipv4_tunnel *tun_key)
>>> {
>>>        int err = 0;
>>>
>>> @@ -343,7 +347,21 @@ static int execute_set_action(struct sk_buff *skb,
>>>                break;
>>>
>>>        case OVS_KEY_ATTR_TUN_ID:
>>> -               OVS_CB(skb)->tun_id = nla_get_be64(nested_attr);
>>> +               if (OVS_CB(skb)->tun_key == NULL) {
>>> +                       /* If tun_key is NULL for this skb, assign it to
>>> +                        * a value the caller passed in for action processing
>>> +                        * and output. This can disappear once we drop support
>>> +                        * for setting tun_id outside of tun_key.
>>> +                        */
>>> +                       memset(tun_key, 0, sizeof(struct ovs_key_ipv4_tunnel));
>>> +                       OVS_CB(skb)->tun_key = tun_key;
>>> +               }
>>> +
>>> +               OVS_CB(skb)->tun_key->tun_id = nla_get_be64(nested_attr);
>>> +               break;
>>> +
>>> +       case OVS_KEY_ATTR_IPV4_TUNNEL:
>>> +               OVS_CB(skb)->tun_key = nla_data(nested_attr);
>>>                break;
>>>
>>>        case OVS_KEY_ATTR_ETHERNET:
>>> @@ -368,7 +386,8 @@ static int execute_set_action(struct sk_buff *skb,
>>>
>>> /* Execute a list of actions against 'skb'. */
>>> static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>>> -                       const struct nlattr *attr, int len, bool keep_skb)
>>> +                       const struct nlattr *attr, int len,
>>> +                       struct ovs_key_ipv4_tunnel *tun_key, bool keep_skb)
>>> {
>>>        /* Every output action needs a separate clone of 'skb', but the common
>>>         * case is just a single output action, so that doing a clone and
>>> @@ -407,7 +426,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>>>                        break;
>>>
>>>                case OVS_ACTION_ATTR_SET:
>>> -                       err = execute_set_action(skb, nla_data(a));
>>> +                       err = execute_set_action(skb, nla_data(a), tun_key);
>>>                        break;
>>>
>>>                case OVS_ACTION_ATTR_SAMPLE:
>>> @@ -458,6 +477,9 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
>>>        struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
>>>        struct loop_counter *loop;
>>>        int error;
>>> +       struct ovs_key_ipv4_tunnel tun_key;
>>> +
>>> +        memset(&tun_key, 0, sizeof(tun_key));
>>>
>> tun key will zeroed while executing tunnel set action, Do we still
>> need to zero it here?
>>
>>>        /* Check whether we've looped too much. */
>>>        loop = &__get_cpu_var(loop_counters);
>>> @@ -469,9 +491,9 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
>>>                goto out_loop;
>>>        }
>>>
>>> -       OVS_CB(skb)->tun_id = 0;
>>> +       OVS_CB(skb)->tun_key = NULL;
>>>        error = do_execute_actions(dp, skb, acts->actions,
>>> -                                        acts->actions_len, false);
>>> +                                        acts->actions_len, &tun_key, false);
>>>
>>>        /* Check whether sub-actions looped too much. */
>>>        if (unlikely(loop->looping))
>>> diff --git a/datapath/datapath.c b/datapath/datapath.c
>>> index a6915fb..d8a198e 100644
>>> --- a/datapath/datapath.c
>>> +++ b/datapath/datapath.c
>>> @@ -587,12 +587,20 @@ static int validate_set(const struct nlattr *a,
>>>
>>>        switch (key_type) {
>>>        const struct ovs_key_ipv4 *ipv4_key;
>>> +       const struct ovs_key_ipv4_tunnel *tun_key;
>>>
>>>        case OVS_KEY_ATTR_PRIORITY:
>>>        case OVS_KEY_ATTR_TUN_ID:
>>>        case OVS_KEY_ATTR_ETHERNET:
>>>                break;
>>>
>>> +       case OVS_KEY_ATTR_IPV4_TUNNEL:
>>> +               tun_key = nla_data(ovs_key);
>>> +               if (!tun_key->ipv4_dst) {
>>> +                       return -EINVAL;
>>> +               }
>>> +               break;
>>> +
>>>        case OVS_KEY_ATTR_IPV4:
>>>                if (flow_key->eth.type != htons(ETH_P_IP))
>>>                        return -EINVAL;
>>> @@ -785,7 +793,7 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
>>>
>>>        err = ovs_flow_metadata_from_nlattrs(&flow->key.phy.priority,
>>>                                             &flow->key.phy.in_port,
>>> -                                            &flow->key.phy.tun_id,
>>> +                                            &flow->key.tun.tun_key,
>>>                                             a[OVS_PACKET_ATTR_KEY]);
>>>        if (err)
>>>                goto err_flow_put;
>>> diff --git a/datapath/datapath.h b/datapath/datapath.h
>>> index affbf0e..c5df12d 100644
>>> --- a/datapath/datapath.h
>>> +++ b/datapath/datapath.h
>>> @@ -96,7 +96,8 @@ struct datapath {
>>> /**
>>>  * struct ovs_skb_cb - OVS data in skb CB
>>>  * @flow: The flow associated with this packet.  May be %NULL if no flow.
>>> - * @tun_id: ID of the tunnel that encapsulated this packet.  It is 0 if the
>>> + * @tun_key: Key for the tunnel that encapsulated this packet. NULL if the
>>> + * packet is not being tunneled.
>>>  * @ip_summed: Consistently stores L4 checksumming status across different
>>>  * kernel versions.
>>>  * @csum_start: Stores the offset from which to start checksumming independent
>>> @@ -107,7 +108,7 @@ struct datapath {
>>>  */
>>> struct ovs_skb_cb {
>>>        struct sw_flow          *flow;
>>> -       __be64                  tun_id;
>>> +       struct ovs_key_ipv4_tunnel  *tun_key;
>>> #ifdef NEED_CSUM_NORMALIZE
>>>        enum csum_type          ip_summed;
>>>        u16                     csum_start;
>>> diff --git a/datapath/flow.c b/datapath/flow.c
>>> index d07337c..376f4be 100644
>>> --- a/datapath/flow.c
>>> +++ b/datapath/flow.c
>>> @@ -629,7 +629,8 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key,
>>>        memset(key, 0, sizeof(*key));
>>>
>>>        key->phy.priority = skb->priority;
>>> -       key->phy.tun_id = OVS_CB(skb)->tun_id;
>>> +       if (OVS_CB(skb)->tun_key)
>>> +               key->tun.tun_key = *OVS_CB(skb)->tun_key;
>>>        key->phy.in_port = in_port;
>>>
>>>        skb_reset_mac_header(skb);
>>> @@ -847,6 +848,7 @@ const int ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
>>>
>>>        /* Not upstream. */
>>>        [OVS_KEY_ATTR_TUN_ID] = sizeof(__be64),
>>> +       [OVS_KEY_ATTR_IPV4_TUNNEL] = sizeof(struct ovs_key_ipv4_tunnel),
>>> };
>>>
>>> static int ipv4_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_len,
>>> @@ -1022,9 +1024,30 @@ int ovs_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_lenp,
>>>                swkey->phy.in_port = DP_MAX_PORTS;
>>>        }
>>>
>>> -       if (attrs & (1ULL << OVS_KEY_ATTR_TUN_ID)) {
>>> -               swkey->phy.tun_id = nla_get_be64(a[OVS_KEY_ATTR_TUN_ID]);
>>> +       /* OVS_KEY_ATTR_TUN_ID and OVS_KEY_ATTR_IPV4_TUNEL must both arrive
>>> +        * together.
>>> +        */
>>> +       if (attrs & (1ULL << OVS_KEY_ATTR_TUN_ID) &&
>>> +           attrs & (1ULL << OVS_KEY_ATTR_IPV4_TUNNEL)) {
>>> +               struct ovs_key_ipv4_tunnel *tun_key;
>>> +               __be64 tun_id = 0;
>>> +               tun_key = nla_data(a[OVS_KEY_ATTR_IPV4_TUNNEL]);
>>> +               tun_id = nla_get_be64(a[OVS_KEY_ATTR_TUN_ID]);
>>> +
>>> +               if (tun_id != tun_key->tun_id)
>>> +                       return -EINVAL;
>>> +
>>> +               swkey->tun.tun_key = *tun_key;
>>>                attrs &= ~(1ULL << OVS_KEY_ATTR_TUN_ID);
>>> +               attrs &= ~(1ULL << OVS_KEY_ATTR_IPV4_TUNNEL);
>>> +       } else if (attrs & (1ULL << OVS_KEY_ATTR_TUN_ID)) {
>>> +               swkey->tun.tun_key.tun_id = nla_get_be64(a[OVS_KEY_ATTR_TUN_ID]);
>>> +               attrs &= ~(1ULL << OVS_KEY_ATTR_TUN_ID);
>>> +       } else if (attrs & (1ULL << OVS_KEY_ATTR_IPV4_TUNNEL)) {
>>> +               struct ovs_key_ipv4_tunnel *tun_key;
>>> +               tun_key = nla_data(a[OVS_KEY_ATTR_IPV4_TUNNEL]);
>>> +               swkey->tun.tun_key = *tun_key;
>>> +               attrs &= ~(1ULL << OVS_KEY_ATTR_IPV4_TUNNEL);
>>>        }
>>
>> While validating set action OVS_KEY_ATTR_IPV4_TUNNEL, we are checking
>> for ipv4_dst, I think we need similar check here.
>>
>>>
>>>        /* Data attributes. */
>>> @@ -1162,14 +1185,16 @@ int ovs_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_lenp,
>>>  * get the metadata, that is, the parts of the flow key that cannot be
>>>  * extracted from the packet itself.
>>>  */
>>> -int ovs_flow_metadata_from_nlattrs(u32 *priority, u16 *in_port, __be64 *tun_id,
>>> +int ovs_flow_metadata_from_nlattrs(u32 *priority, u16 *in_port,
>>> +                                  struct ovs_key_ipv4_tunnel *tun_key,
>>>                                   const struct nlattr *attr)
>>> {
>>>        const struct nlattr *nla;
>>>        int rem;
>>> +       __be64 tun_id = 0;
>>>
>>>        *in_port = DP_MAX_PORTS;
>>> -       *tun_id = 0;
>>> +       memset(tun_key, 0, sizeof(*tun_key));
>>>        *priority = 0;
>>>
>>>        nla_for_each_nested(nla, attr, rem) {
>>> @@ -1185,7 +1210,20 @@ int ovs_flow_metadata_from_nlattrs(u32 *priority, u16 *in_port, __be64 *tun_id,
>>>                                break;
>>>
>>>                        case OVS_KEY_ATTR_TUN_ID:
>>> -                               *tun_id = nla_get_be64(nla);
>>> +                               tun_id = nla_get_be64(nla);
>>> +                               if ((tun_key->tun_flags & FLOW_TNL_F_KEY) &&
>>> +                                   tun_key->tun_id != tun_id)
>>> +                                       return -EINVAL;
>>> +                               break;
>>> +
>>> +                       case OVS_KEY_ATTR_IPV4_TUNNEL:
>>> +                               if (tun_key->tun_flags & FLOW_TNL_F_KEY)
>>> +                                       tun_id = tun_key->tun_id;
>>> +                               memcpy(tun_key, nla_data(nla),
>>> +                                      sizeof(*tun_key));
>>> +                               if ((tun_key->tun_flags & FLOW_TNL_F_KEY) &&
>>> +                                   tun_id != tun_key->tun_id)
>>> +                                       return -EINVAL;
>>>                                break;
>>>
>>>                        case OVS_KEY_ATTR_IN_PORT:
>>> @@ -1210,10 +1248,20 @@ int ovs_flow_to_nlattrs(const struct sw_flow_key *swkey, struct sk_buff *skb)
>>>            nla_put_u32(skb, OVS_KEY_ATTR_PRIORITY, swkey->phy.priority))
>>>                goto nla_put_failure;
>>>
>>> -       if (swkey->phy.tun_id != cpu_to_be64(0) &&
>>> -           nla_put_be64(skb, OVS_KEY_ATTR_TUN_ID, swkey->phy.tun_id))
>>> +        if ((swkey->tun.tun_key.tun_flags & FLOW_TNL_F_KEY) &&
>>> +           nla_put_be64(skb, OVS_KEY_ATTR_TUN_ID, swkey->tun.tun_key.tun_id))
>>>                goto nla_put_failure;
>>>
>>> +       if (swkey->tun.tun_key.ipv4_dst) {
>>> +               struct ovs_key_ipv4_tunnel *tun_key;
>>> +               nla = nla_reserve(skb, OVS_KEY_ATTR_IPV4_TUNNEL,
>>> +                                 sizeof(*tun_key));
>>> +               if (!nla)
>>> +                       goto nla_put_failure;
>>> +               tun_key = nla_data(nla);
>>> +               *tun_key = swkey->tun.tun_key;
>>> +       }
>>> +
>>
>> Why are we sending both OVS_KEY_ATTR_TUN_ID and
>> OVS_KEY_ATTR_IPV4_TUNNEL attributed here?
>> we could first check for ipv4_dst else for FLOW_TNL_F_KEY in flow key.
>>
>>>        if (swkey->phy.in_port != DP_MAX_PORTS &&
>>>            nla_put_u32(skb, OVS_KEY_ATTR_IN_PORT, swkey->phy.in_port))
>>>                goto nla_put_failure;
>>> diff --git a/datapath/flow.h b/datapath/flow.h
>>> index 02c563a..4430b32 100644
>>> --- a/datapath/flow.h
>>> +++ b/datapath/flow.h
>>> @@ -42,10 +42,12 @@ struct sw_flow_actions {
>>>
>>> struct sw_flow_key {
>>>        struct {
>>> -               __be64  tun_id;         /* Encapsulating tunnel ID. */
>>>                u32     priority;       /* Packet QoS priority. */
>>>                u16     in_port;        /* Input switch port (or DP_MAX_PORTS). */
>>>        } phy;
>>> +        struct {
>>> +               struct ovs_key_ipv4_tunnel tun_key;  /* Encapsulating tunnel key. */
>>> +       } tun;
>>>        struct {
>>>                u8     src[ETH_ALEN];   /* Ethernet source address. */
>>>                u8     dst[ETH_ALEN];   /* Ethernet destination address. */
>>> @@ -150,6 +152,7 @@ u64 ovs_flow_used_time(unsigned long flow_jiffies);
>>>  *                         ------  ---  ------  -----
>>>  *  OVS_KEY_ATTR_PRIORITY      4    --     4      8
>>>  *  OVS_KEY_ATTR_TUN_ID        8    --     4     12
>>> + *  OVS_KEY_ATTR_IPV4_TUNNEL  24    --     4     28
>>>  *  OVS_KEY_ATTR_IN_PORT       4    --     4      8
>>>  *  OVS_KEY_ATTR_ETHERNET     12    --     4     16
>>>  *  OVS_KEY_ATTR_ETHERTYPE     2     2     4      8  (outer VLAN ethertype)
>>> @@ -160,14 +163,15 @@ u64 ovs_flow_used_time(unsigned long flow_jiffies);
>>>  *  OVS_KEY_ATTR_ICMPV6        2     2     4      8
>>>  *  OVS_KEY_ATTR_ND           28    --     4     32
>>>  *  -------------------------------------------------
>>> - *  total                                       156
>>> + *  total                                       184
>>>  */
>>> -#define FLOW_BUFSIZE 156
>>> +#define FLOW_BUFSIZE 184
>>>
>>> int ovs_flow_to_nlattrs(const struct sw_flow_key *, struct sk_buff *);
>>> int ovs_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_lenp,
>>>                      const struct nlattr *);
>>> -int ovs_flow_metadata_from_nlattrs(u32 *priority, u16 *in_port, __be64 *tun_id,
>>> +int ovs_flow_metadata_from_nlattrs(u32 *priority, u16 *in_port,
>>> +                                  struct ovs_key_ipv4_tunnel *tun_key,
>>>                                   const struct nlattr *);
>>>
>>> #define MAX_ACTIONS_BUFSIZE    (16 * 1024)
>>> diff --git a/datapath/tunnel.c b/datapath/tunnel.c
>>> index d651c11..739f098 100644
>>> --- a/datapath/tunnel.c
>>> +++ b/datapath/tunnel.c
>>> @@ -367,9 +367,9 @@ struct vport *ovs_tnl_find_port(struct net *net, __be32 saddr, __be32 daddr,
>>>        return NULL;
>> ñ>  }
>>>
>>> -static void ecn_decapsulate(struct sk_buff *skb, u8 tos)
>>> +static void ecn_decapsulate(struct sk_buff *skb)
>>> {
>>> -       if (unlikely(INET_ECN_is_ce(tos))) {
>>> +       if (unlikely(INET_ECN_is_ce(OVS_CB(skb)->tun_key->ipv4_tos))) {
>>>                __be16 protocol = skb->protocol;
>>>
>>>                skb_set_network_header(skb, ETH_HLEN);
>>> @@ -416,7 +416,7 @@ static void ecn_decapsulate(struct sk_buff *skb, u8 tos)
>>>  * - skb->csum does not include the inner Ethernet header.
>>>  * - The layer pointers are undefined.
>>>  */
>>> -void ovs_tnl_rcv(struct vport *vport, struct sk_buff *skb, u8 tos)
>>> +void ovs_tnl_rcv(struct vport *vport, struct sk_buff *skb)
>>> {
>>>        struct ethhdr *eh;
>>>
>>> @@ -433,7 +433,7 @@ void ovs_tnl_rcv(struct vport *vport, struct sk_buff *skb, u8 tos)
>>>        skb_clear_rxhash(skb);
>>>        secpath_reset(skb);
>>>
>>> -       ecn_decapsulate(skb, tos);
>>> +       ecn_decapsulate(skb);
>>>        vlan_set_tci(skb, 0);
>>>
>>>        if (unlikely(compute_ip_summed(skb, false))) {
>>> @@ -613,7 +613,7 @@ static void ipv6_build_icmp(struct sk_buff *skb, struct sk_buff *nskb,
>>>
>>> bool ovs_tnl_frag_needed(struct vport *vport,
>>>                         const struct tnl_mutable_config *mutable,
>>> -                        struct sk_buff *skb, unsigned int mtu, __be64 flow_key)
>>> +                        struct sk_buff *skb, unsigned int mtu)
>>> {
>>>        unsigned int eth_hdr_len = ETH_HLEN;
>>>        unsigned int total_length = 0, header_length = 0, payload_length;
>>> @@ -697,17 +697,6 @@ bool ovs_tnl_frag_needed(struct vport *vport,
>>>                ipv6_build_icmp(skb, nskb, mtu, payload_length);
>>> #endif
>>>
>>> -       /*
>>> -        * Assume that flow based keys are symmetric with respect to input
>>> -        * and output and use the key that we were going to put on the
>>> -        * outgoing packet for the fake received packet.  If the keys are
>>> -        * not symmetric then PMTUD needs to be disabled since we won't have
>>> -        * any way of synthesizing packets.
>>> -        */
>>> -       if ((mutable->flags & (TNL_F_IN_KEY_MATCH | TNL_F_OUT_KEY_ACTION)) ==
>>> -           (TNL_F_IN_KEY_MATCH | TNL_F_OUT_KEY_ACTION))
>>> -               OVS_CB(nskb)->tun_id = flow_key;
>>> -
>>>        if (unlikely(compute_ip_summed(nskb, false))) {
>>>                kfree_skb(nskb);
>>>                return false;
>>> @@ -723,12 +712,20 @@ static bool check_mtu(struct sk_buff *skb,
>>>                      const struct tnl_mutable_config *mutable,
>>>                      const struct rtable *rt, __be16 *frag_offp)
>>> {
>>> -       bool df_inherit = mutable->flags & TNL_F_DF_INHERIT;
>>> +       bool df_inherit;
>>>        bool pmtud = mutable->flags & TNL_F_PMTUD;
>>> -       __be16 frag_off = mutable->flags & TNL_F_DF_DEFAULT ? htons(IP_DF) : 0;
>>> +       __be16 frag_off;
>>>        int mtu = 0;
>>>        unsigned int packet_length = skb->len - ETH_HLEN;
>>>
>>> +       if (OVS_CB(skb)->tun_key->ipv4_dst != 0) {
>>> +               df_inherit = false;
>>> +               frag_off = OVS_CB(skb)->tun_key->tun_flags & FLOW_TNL_F_DONT_FRAGMENT;
>>> +       } else {
>>> +               df_inherit = mutable->flags & TNL_F_DF_INHERIT;
>>> +               frag_off = mutable->flags & TNL_F_DF_DEFAULT ? htons(IP_DF) : 0;
>>> +        }
>>> +
>> Why not set pmtud to false incase of flow-based tunneling like you did
>> it for df_inherit?
>>
>>>        /* Allow for one level of tagging in the packet length. */
>>>        if (!vlan_tx_tag_present(skb) &&
>>>            eth_hdr(skb)->h_proto == htons(ETH_P_8021Q))
>>> @@ -760,8 +757,7 @@ static bool check_mtu(struct sk_buff *skb,
>>>                        mtu = max(mtu, IP_MIN_MTU);
>>>
>>>                        if (packet_length > mtu &&
>>> -                           ovs_tnl_frag_needed(vport, mutable, skb, mtu,
>>> -                                               OVS_CB(skb)->tun_id))
>>> +                           ovs_tnl_frag_needed(vport, mutable, skb, mtu))
>>>                                return false;
>>>                }
>>>        }
>>> @@ -777,8 +773,7 @@ static bool check_mtu(struct sk_buff *skb,
>>>                        mtu = max(mtu, IPV6_MIN_MTU);
>>>
>>>                        if (packet_length > mtu &&
>>> -                           ovs_tnl_frag_needed(vport, mutable, skb, mtu,
>>> -                                               OVS_CB(skb)->tun_id))
>>> +                           ovs_tnl_frag_needed(vport, mutable, skb, mtu))
>>>                                return false;
>>>                }
>>>        }
>>> @@ -1000,15 +995,16 @@ unlock:
>>> }
>>>
>>> static struct rtable *__find_route(const struct tnl_mutable_config *mutable,
>>> -                                  u8 ipproto, u8 tos)
>>> +                                  __be32 saddr, __be32 daddr, u8 ipproto,
>>> +                                  u8 tos)
>>> {
>>>        /* Tunnel configuration keeps DSCP part of TOS bits, But Linux
>>>         * router expect RT_TOS bits only. */
>>>
>>> #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,39)
>>>        struct flowi fl = { .nl_u = { .ip4_u = {
>>> -                                       .daddr = mutable->key.daddr,
>>> -                                       .saddr = mutable->key.saddr,
>>> +                                       .daddr = daddr,
>>> +                                       .saddr = saddr,
>>>                                        .tos   = RT_TOS(tos) } },
>>>                                        .proto = ipproto };
>>>        struct rtable *rt;
>>> @@ -1018,8 +1014,8 @@ static struct rtable *__find_route(const struct tnl_mutable_config *mutable,
>>>
>>>        return rt;
>>> #else
>>> -       struct flowi4 fl = { .daddr = mutable->key.daddr,
>>> -                            .saddr = mutable->key.saddr,
>>> +       struct flowi4 fl = { .daddr = daddr,
>>> +                            .saddr = saddr,
>>>                             .flowi4_tos = RT_TOS(tos),
>>>                             .flowi4_proto = ipproto };
>>>
>>> @@ -1029,7 +1025,8 @@ static struct rtable *__find_route(const struct tnl_mutable_config *mutable,
>>>
>>> static struct rtable *find_route(struct vport *vport,
>>>                                 const struct tnl_mutable_config *mutable,
>>> -                                u8 tos, struct tnl_cache **cache)
>>> +                                __be32 saddr, __be32 daddr, u8 tos,
>>> +                                struct tnl_cache **cache)
>>> {
>>>        struct tnl_vport *tnl_vport = tnl_vport_priv(vport);
>>>        struct tnl_cache *cur_cache = rcu_dereference(tnl_vport->cache);
>>> @@ -1037,18 +1034,21 @@ static struct rtable *find_route(struct vport *vport,
>>>        *cache = NULL;
>>>        tos = RT_TOS(tos);
>>>
>>> -       if (likely(tos == RT_TOS(mutable->tos) &&
>>> -           check_cache_valid(cur_cache, mutable))) {
>>> +       if (daddr == mutable->key.daddr && saddr == mutable->key.saddr &&
>>> +           tos == RT_TOS(mutable->tos) &&
>>> +           check_cache_valid(cur_cache, mutable)) {
>>>                *cache = cur_cache;
>>>                return cur_cache->rt;
>>>        } else {
>>>                struct rtable *rt;
>>>
>>> -               rt = __find_route(mutable, tnl_vport->tnl_ops->ipproto, tos);
>>> +               rt = __find_route(mutable, saddr, daddr,
>>> +                                 tnl_vport->tnl_ops->ipproto, tos);
>>>                if (IS_ERR(rt))
>>>                        return NULL;
>>>
>>> -               if (likely(tos == RT_TOS(mutable->tos)))
>>> +               if (daddr == mutable->key.daddr && saddr == mutable->key.saddr &&
>>> +                   tos == RT_TOS(mutable->tos))
>>>                        *cache = build_cache(vport, mutable, rt);
>>>
>> I am not sure why checks are added on saddr and daddr here?
>> header caching is not set in case of flow based tunneling to
>> build_cache call is no-op anyways.
>>
>>>                return rt;
>>> @@ -1178,8 +1178,11 @@ int ovs_tnl_send(struct vport *vport, struct sk_buff *skb)
>>>        struct rtable *rt;
>>>        struct dst_entry *unattached_dst = NULL;
>>>        struct tnl_cache *cache;
>>> +       struct ovs_key_ipv4_tunnel tun_key;
>>>        int sent_len = 0;
>>>        __be16 frag_off = 0;
>>> +       __be32 daddr;
>>> +       __be32 saddr;
>>>        u8 ttl;
>>>        u8 inner_tos;
>>>        u8 tos;
>>> @@ -1207,6 +1210,13 @@ int ovs_tnl_send(struct vport *vport, struct sk_buff *skb)
>>>        }
>>> #endif
>>>
>>> +       /* If OVS_CB(skb)->tun_key is NULL, point it at the local tun_key here,
>>> +        * and zero it out.
>>> +        */
>>> +       if (OVS_CB(skb)->tun_key == NULL) {
>>> +               memset(&tun_key, 0, sizeof(tun_key));
>>> +               OVS_CB(skb)->tun_key = &tun_key;
>>> +       }
>>>        /* ToS */
>>>        if (skb->protocol == htons(ETH_P_IP))
>>>                inner_tos = ip_hdr(skb)->tos;
>>> @@ -1219,11 +1229,23 @@ int ovs_tnl_send(struct vport *vport, struct sk_buff *skb)
>>>
>>>        if (mutable->flags & TNL_F_TOS_INHERIT)
>>>                tos = inner_tos;
>>> +       else if (OVS_CB(skb)->tun_key->ipv4_dst != 0)
>>> +               tos = OVS_CB(skb)->tun_key->ipv4_tos;
>>>        else
>>>                tos = mutable->tos;
>>>
>>> +       if (OVS_CB(skb)->tun_key->ipv4_dst != 0)
>>> +               daddr = OVS_CB(skb)->tun_key->ipv4_dst;
>>> +       else
>>> +               daddr = mutable->key.daddr;
>>> +
>>> +       if (OVS_CB(skb)->tun_key->ipv4_dst != 0)
>>> +               saddr = OVS_CB(skb)->tun_key->ipv4_src;
>>> +       else
>>> +               saddr = mutable->key.saddr;
>>> +
>>
>> It will be easier to read if we have one if check on
>> OVS_CB(skb)->tun_key->ipv4_dst which is retrieve all tunnel parameter
>> for flow-based tunning and else block for campat code.
>>
>>>        /* Route lookup */
>>> -       rt = find_route(vport, mutable, tos, &cache);
>>> +       rt = find_route(vport, mutable, saddr, daddr, tos, &cache);
>>>        if (unlikely(!rt))
>>>                goto error_free;
>>>        if (unlikely(!cache))
>>> @@ -1260,9 +1282,13 @@ int ovs_tnl_send(struct vport *vport, struct sk_buff *skb)
>>>        }
>>>
>>>        /* TTL */
>>> -       ttl = mutable->ttl;
>>> -       if (!ttl)
>>> -               ttl = ip4_dst_hoplimit(&rt_dst(rt));
>>> +       if (OVS_CB(skb)->tun_key->ipv4_dst != 0)
>>> +               ttl = OVS_CB(skb)->tun_key->ipv4_ttl;
>>> +       else {
>>> +               ttl = mutable->ttl;
>>> +               if (!ttl)
>>> +                       ttl = ip4_dst_hoplimit(&rt_dst(rt));
>>> +       }
>>>
>>>        if (mutable->flags & TNL_F_TTL_INHERIT) {
>>
>> This check could be in the compat code block, so it is less confusing.
>>
>>>                if (skb->protocol == htons(ETH_P_IP))
>>> @@ -1442,7 +1468,8 @@ static int tnl_set_config(struct net *net, struct nlattr *options,
>>>                struct net_device *dev;
>>>                struct rtable *rt;
>>>
>>> -               rt = __find_route(mutable, tnl_ops->ipproto, mutable->tos);
>>> +               rt = __find_route(mutable, mutable->key.saddr, mutable->key.daddr,
>>> +                                 tnl_ops->ipproto, mutable->tos);
>>>                if (IS_ERR(rt))
>>>                        return -EADDRNOTAVAIL;
>>>                dev = rt_dst(rt).dev;
>>> diff --git a/datapath/tunnel.h b/datapath/tunnel.h
>>> index 1924017..b7858d3 100644
>>> --- a/datapath/tunnel.h
>>> +++ b/datapath/tunnel.h
>>> @@ -269,14 +269,14 @@ int ovs_tnl_set_addr(struct vport *vport, const unsigned char *addr);
>>> const char *ovs_tnl_get_name(const struct vport *vport);
>>> const unsigned char *ovs_tnl_get_addr(const struct vport *vport);
>>> int ovs_tnl_send(struct vport *vport, struct sk_buff *skb);
>>> -void ovs_tnl_rcv(struct vport *vport, struct sk_buff *skb, u8 tos);
>>> +void ovs_tnl_rcv(struct vport *vport, struct sk_buff *skb);
>>>
>>> struct vport *ovs_tnl_find_port(struct net *net, __be32 saddr, __be32 daddr,
>>>                                __be64 key, int tunnel_type,
>>>                                const struct tnl_mutable_config **mutable);
>>> bool ovs_tnl_frag_needed(struct vport *vport,
>>>                         const struct tnl_mutable_config *mutable,
>>> -                        struct sk_buff *skb, unsigned int mtu, __be64 flow_key);
>>> +                        struct sk_buff *skb, unsigned int mtu);
>>> void ovs_tnl_free_linked_skbs(struct sk_buff *skb);
>>>
>>> int ovs_tnl_init(void);
>>> @@ -286,4 +286,15 @@ static inline struct tnl_vport *tnl_vport_priv(const struct vport *vport)
>>>        return vport_priv(vport);
>>> }
>>>
>>> +static inline void tnl_tun_key_init(struct ovs_key_ipv4_tunnel *tun_key,
>>> +                                   const struct iphdr *iph, __be64 tun_id)
>>> +{
>>> +       tun_key->tun_id = tun_id;
>>> +       tun_key->ipv4_src = iph->saddr;
>>> +       tun_key->ipv4_dst = iph->daddr;
>>> +       tun_key->ipv4_tos = iph->tos;
>>> +       tun_key->ipv4_ttl = iph->ttl;
>>> +       tun_key->tun_flags = 0;
>>> +}
>>> +
>>> #endif /* tunnel.h */
>>> diff --git a/datapath/vport-capwap.c b/datapath/vport-capwap.c
>>> index 05a099d..fbf50d9 100644
>>> --- a/datapath/vport-capwap.c
>>> +++ b/datapath/vport-capwap.c
>>> @@ -220,7 +220,7 @@ static struct sk_buff *capwap_update_header(const struct vport *vport,
>>>                struct capwaphdr_wsi *wsi = (struct capwaphdr_wsi *)(cwh + 1);
>>>                struct capwaphdr_wsi_key *opt = (struct capwaphdr_wsi_key *)(wsi + 1);
>>>
>>> -               opt->key = OVS_CB(skb)->tun_id;
>>> +               opt->key = OVS_CB(skb)->tun_key->tun_id;
>>>        }
>>>
>>>        udph->len = htons(skb->len - skb_transport_offset(skb));
>>> @@ -316,6 +316,7 @@ static int capwap_rcv(struct sock *sk, struct sk_buff *skb)
>>>        struct vport *vport;
>>>        const struct tnl_mutable_config *mutable;
>>>        struct iphdr *iph;
>>> +       struct ovs_key_ipv4_tunnel tun_key;
>>>        __be64 key = 0;
>>>
>>>        if (unlikely(!pskb_may_pull(skb, CAPWAP_MIN_HLEN + ETH_HLEN)))
>>> @@ -333,12 +334,11 @@ static int capwap_rcv(struct sock *sk, struct sk_buff *skb)
>>>                goto error;
>>>        }
>>>
>>> -       if (mutable->flags & TNL_F_IN_KEY_MATCH)
>>> -               OVS_CB(skb)->tun_id = key;
>>> -       else
>>> -               OVS_CB(skb)->tun_id = 0;
>>> +       tnl_tun_key_init(&tun_key, iph,
>>> +                    mutable->flags & TNL_F_IN_KEY_MATCH ? key : 0);
>>> +       OVS_CB(skb)->tun_key = &tun_key;
>>>
>>> -       ovs_tnl_rcv(vport, skb, iph->tos);
>>> +       ovs_tnl_rcv(vport, skb);
>>>        goto out;
>>>
>>> error:
>>> diff --git a/datapath/vport-gre.c b/datapath/vport-gre.c
>>> index ab89c5b..8076b1d 100644
>>> --- a/datapath/vport-gre.c
>>> +++ b/datapath/vport-gre.c
>>> @@ -103,7 +103,7 @@ static struct sk_buff *gre_update_header(const struct vport *vport,
>>>
>>>        /* Work backwards over the options so the checksum is last. */
>>>        if (mutable->flags & TNL_F_OUT_KEY_ACTION)
>>> -               *options = be64_get_low32(OVS_CB(skb)->tun_id);
>>> +               *options = be64_get_low32(OVS_CB(skb)->tun_key->tun_id);
>>>
>> Here we do need check if we doing flow-based tunneling. in case of
>> flow-based tunneling mutable is shared between all tunnels, so there
>> is no-way to we can do port specific flags check from mutable. about
>> GRE checksum, we need to check for FLOW_TNL_F_CSUM flag for doing
>> checksum on a packet.
>>
>>>        if (mutable->out_key || mutable->flags & TNL_F_OUT_KEY_ACTION)
>>>                options--;
>>> @@ -285,7 +285,7 @@ static void gre_err(struct sk_buff *skb, u32 info)
>>> #endif
>>>
>>>        __skb_pull(skb, tunnel_hdr_len);
>>> -       ovs_tnl_frag_needed(vport, mutable, skb, mtu, key);
>>> +       ovs_tnl_frag_needed(vport, mutable, skb, mtu);
>>>        __skb_push(skb, tunnel_hdr_len);
>>>
>> same here, tunnel_hdr_len is stored in mutable which is going to be
>> shared for all tunnels for a type in flow based tunneling, so we need
>> to calculate it on packet send.
>>
> I looked, and in the context of this function, tunnel_hdr_len is actually calculated
> by the static function parse_header(), which actually is looking at the packet to
> find it. Now, in the broader context, mutable does have a tunnel header as a part
> of it, and if that's the tunnel header length you are concerned about, I agree we
> need to address that. Can you confirm?
>

Right, I misplaced this comment. While rcv is tunnel_hlen is right, on
send side tunnel_hlen needs fix.

Thanks,
Pravin.



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