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Date: Fri, 25 Sep 2015 18:35:27 -0400
From: Thomas F Herbert <thomasfherbert@...il.com>
To: Pravin Shelar <pshelar@...ira.com>
Cc: netdev <netdev@...r.kernel.org>, therbert@...hat.com,
"dev@...nvswitch.org" <dev@...nvswitch.org>
Subject: Re: [PATCH 3/3] 802.1AD: Flow handling, actions, vlan parsing and
netlink attributes
Pravin,
Another comment and question. Please seen inline below.
Thanks,
--Tom
On 9/24/15 7:42 PM, Pravin Shelar wrote:
> On Thu, Sep 24, 2015 at 10:58 AM, Thomas F Herbert
> <thomasfherbert@...il.com> wrote:
>> Add support for 802.1ad including the ability to push and pop double
>> tagged vlans. Add support for 802.1ad to netlink parsing and flow
>> conversion. Uses double nested encap attributes to represent double
>> tagged vlan. Inner TPID encoded along with ctci in nested attributes.
>>
>> Signed-off-by: Thomas F Herbert <thomasfherbert@...il.com>
>> ---
>> net/openvswitch/flow.c | 83 +++++++++++++++++----
>> net/openvswitch/flow.h | 5 ++
>> net/openvswitch/flow_netlink.c | 166 ++++++++++++++++++++++++++++++++++++++---
>> 3 files changed, 230 insertions(+), 24 deletions(-)
>>
>> diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
>> index c8db44a..db58e47 100644
>> --- a/net/openvswitch/flow.c
>> +++ b/net/openvswitch/flow.c
>> @@ -305,21 +305,77 @@ static bool icmp6hdr_ok(struct sk_buff *skb)
>> static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
>> {
>> struct qtag_prefix {
>> - __be16 eth_type; /* ETH_P_8021Q */
>> + __be16 eth_type; /* ETH_P_8021Q or ETH_P_8021AD */
>> __be16 tci;
>> };
>> - struct qtag_prefix *qp;
>> + struct qtag_prefix *qp = (struct qtag_prefix *)skb->data;
>>
>> - if (unlikely(skb->len < sizeof(struct qtag_prefix) + sizeof(__be16)))
>> + struct qinqtag_prefix {
>> + __be16 eth_type; /* ETH_P_8021Q or ETH_P_8021AD */
>> + __be16 tci;
>> + __be16 inner_tpid; /* ETH_P_8021Q */
>> + __be16 ctci;
>> + };
>> +
>> + if (likely(skb_vlan_tag_present(skb))) {
>> + key->eth.tci = htons(skb->vlan_tci);
>> +
>> + /* Case where upstream
>> + * processing has already stripped the outer vlan tag.
>> + */
>> + if (unlikely(skb->vlan_proto == htons(ETH_P_8021AD))) {
>> + if (unlikely(skb->len < sizeof(struct qtag_prefix) +
>> + sizeof(__be16))) {
>> + key->eth.tci = 0;
>> + return 0;
>> + }
>> +
>> + if (unlikely(!pskb_may_pull(skb,
>> + sizeof(struct qtag_prefix) +
>> + sizeof(__be16))))
>> + return -ENOMEM;
>> +
> qp pointer is no longer valid after pskb_may_pull() call.
>
>> + key->eth.cvlan.ctci =
>> + qp->tci | htons(VLAN_TAG_PRESENT);
>> + key->eth.cvlan.c_tpid = qp->eth_type;
>> +
>> + __skb_pull(skb, sizeof(struct qtag_prefix));
>> + }
>> return 0;
>> + }
>>
>> - if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
>> - sizeof(__be16))))
>> - return -ENOMEM;
>>
>> - qp = (struct qtag_prefix *) skb->data;
>> - key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
>> - __skb_pull(skb, sizeof(struct qtag_prefix));
>
> qp access is done without skb_may_pull() call.
>> + if (qp->eth_type == htons(ETH_P_8021AD)) {
>> + struct qinqtag_prefix *qinqp =
>> + (struct qinqtag_prefix *)skb->data;
>> +
>> + if (unlikely(skb->len < sizeof(struct qinqtag_prefix) +
>> + sizeof(__be16)))
>> + return 0;
>> +
>> + if (unlikely(!pskb_may_pull(skb, sizeof(struct qinqtag_prefix) +
>> + sizeof(__be16))))
>> + return -ENOMEM;
>
> same as above qinqp pointer is not valid after psk_may_pull().
>
>> + key->eth.tci = qinqp->tci | htons(VLAN_TAG_PRESENT);
>> + key->eth.cvlan.ctci = qinqp->ctci | htons(VLAN_TAG_PRESENT);
>> + key->eth.cvlan.c_tpid = qinqp->inner_tpid;
>> +
>> + __skb_pull(skb, sizeof(struct qinqtag_prefix));
>> +
>> + return 0;
>> + }
>> + if (qp->eth_type == htons(ETH_P_8021Q)) {
>> + if (unlikely(skb->len < sizeof(struct qtag_prefix) +
>> + sizeof(__be16)))
>> + return -ENOMEM;
>> +
>> + if (unlikely(!pskb_may_pull(skb, sizeof(struct qtag_prefix) +
>> + sizeof(__be16))))
>> + return 0;
> same issue as above.
>
>> + key->eth.tci = qp->tci | htons(VLAN_TAG_PRESENT);
>> +
>> + __skb_pull(skb, sizeof(struct qtag_prefix));
>> + }
>>
>> return 0;
>> }
> ...
>
>> diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
>> index fe527d2..2c491e8 100644
>> --- a/net/openvswitch/flow.h
>> +++ b/net/openvswitch/flow.h
>> @@ -69,6 +69,11 @@ struct sw_flow_key {
>> u8 src[ETH_ALEN]; /* Ethernet source address. */
>> u8 dst[ETH_ALEN]; /* Ethernet destination address. */
>> __be16 tci; /* 0 if no VLAN, VLAN_TAG_PRESENT set otherwise. */
Do you think I should I also add tpid here with tci for the outer vlan
as a struct? Please see comment below.
>> + struct {
>> + __be16 c_tpid; /* Vlan DL_type 802.1q or 802.1ad */
>> + __be16 ctci; /* 0 if no CVLAN, VLAN_TAG_PRESENT */
> Lets call c_tpid type and ctci tci, to keep naming consistent with outer vlan.
>> + /* set otherwise. */
>> + } cvlan;
>> __be16 type; /* Ethernet frame type. */
>> } eth;
>> union {
>> diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
>> index c92d6a2..5fe415d 100644
>> --- a/net/openvswitch/flow_netlink.c
>> +++ b/net/openvswitch/flow_netlink.c
> ...
>
>> @@ -1064,6 +1085,80 @@ static void mask_set_nlattr(struct nlattr *attr, u8 val)
>> nlattr_set(attr, val, ovs_key_lens);
>> }
>>
>> +static int parse_vlan_from_nlattrs(const struct nlattr **nla,
>> + struct sw_flow_match *match,
>> + u64 *key_attrs, bool *ie_valid,
>> + const struct nlattr **a, bool is_mask,
>> + bool log)
>> +{
>> + int err;
>> + const struct nlattr *encap;
>> +
>> + *ie_valid = false;
>> + if (!is_mask) {
>> + u64 v_attrs = 0;
>> +
>> + err = parse_flow_nlattrs(*nla, a, &v_attrs, log);
>> + if (err)
>> + return err;
>> + /* Another encap attribute here indicates
>> + * the presence of a double tagged vlan.
>> + */
>> + if ((v_attrs & (1 << OVS_KEY_ATTR_ETHERTYPE)) &&
>> + eth_type_vlan(nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]))) {
>> + if (!((v_attrs & (1ULL << OVS_KEY_ATTR_VLAN)) &&
>> + (v_attrs & (1ULL << OVS_KEY_ATTR_ENCAP)))) {
>> + OVS_NLERR(log, "Invalid Inner VLAN frame");
>> + return -EINVAL;
>> + }
>> + encap = a[OVS_KEY_ATTR_ENCAP];
>> + v_attrs &= ~(1 << OVS_KEY_ATTR_ENCAP);
>> +
>> + err = cust_vlan_from_nlattrs(match, a, is_mask, log);
>> + if (err)
>> + return err;
>> + *ie_valid = true;
>> + *nla = encap;
>> +
>> + /* Insure that tci key attribute isn't
>> + * overwritten by encapsulated customer tci.
>> + * Ethertype is cleared because it is c_tpid.
>> + */
>> + v_attrs &= ~(1 << OVS_KEY_ATTR_VLAN);
>> + v_attrs &= ~(1 << OVS_KEY_ATTR_ETHERTYPE);
>> + }
>> + *key_attrs |= v_attrs;
>> +
>> + } else {
>> + u64 mask_v_attrs = 0;
>> +
>> + err = parse_flow_mask_nlattrs(*nla, a, &mask_v_attrs, log);
>> + if (err)
>> + return err;
>> +
>> + if (mask_v_attrs & 1 << OVS_KEY_ATTR_ENCAP) {
>> + if (!*ie_valid) {
>> + OVS_NLERR(log, "Encap mask attribute is set for non-CVLAN frame.");
>> + err = -EINVAL;
> No need to set err it is not read again.
>
>> + return err;
>> + }
> At the beginning of this same function ie_valid is set to false. So
> this case always return error resulting failure in flow install. This
> make me wonder if you ever tested this code with multiple encap
> traffic.
>
>> + encap = a[OVS_KEY_ATTR_ENCAP];
>> + mask_v_attrs &= ~(1 << OVS_KEY_ATTR_ENCAP);
>> +
>> + err = cust_vlan_from_nlattrs(match, a, is_mask, log);
>> + if (err)
>> + return err;
>> + *nla = encap;
>> +
>> + mask_v_attrs &= ~(1ULL << OVS_KEY_ATTR_VLAN);
>> + mask_v_attrs &= ~(1ULL << OVS_KEY_ATTR_ETHERTYPE);
>> + }
>> +
>> + *key_attrs |= mask_v_attrs;
>> + }
>> + return 0;
>> +}
>> +
>> /**
>> * ovs_nla_get_match - parses Netlink attributes into a flow key and
>> * mask. In case the 'mask' is NULL, the flow is treated as exact match
>> @@ -1091,6 +1186,7 @@ int ovs_nla_get_match(struct net *net, struct sw_flow_match *match,
>> u64 key_attrs = 0;
>> u64 mask_attrs = 0;
>> bool encap_valid = false;
>> + bool i_encap_valid = false;
>> int err;
>>
>> err = parse_flow_nlattrs(nla_key, a, &key_attrs, log);
>> @@ -1099,11 +1195,11 @@ int ovs_nla_get_match(struct net *net, struct sw_flow_match *match,
>>
>> if ((key_attrs & (1 << OVS_KEY_ATTR_ETHERNET)) &&
>> (key_attrs & (1 << OVS_KEY_ATTR_ETHERTYPE)) &&
>> - (nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]) == htons(ETH_P_8021Q))) {
>> + eth_type_vlan(nla_get_be16(a[OVS_KEY_ATTR_ETHERTYPE]))) {
>> __be16 tci;
>>
>> - if (!((key_attrs & (1 << OVS_KEY_ATTR_VLAN)) &&
>> - (key_attrs & (1 << OVS_KEY_ATTR_ENCAP)))) {
>> + if (!((key_attrs & (1ULL << OVS_KEY_ATTR_VLAN)) &&
>> + (key_attrs & (1ULL << OVS_KEY_ATTR_ENCAP)))) {
>> OVS_NLERR(log, "Invalid Vlan frame.");
>> return -EINVAL;
>> }
>> @@ -1115,9 +1211,19 @@ int ovs_nla_get_match(struct net *net, struct sw_flow_match *match,
>> encap_valid = true;
>>
>> if (tci & htons(VLAN_TAG_PRESENT)) {
>> - err = parse_flow_nlattrs(encap, a, &key_attrs, log);
>> + err = parse_vlan_from_nlattrs(&encap, match, &key_attrs,
>> + &i_encap_valid, a, false,
>> + log);
>> if (err)
>> return err;
>> +
>> + if (i_encap_valid) {
>> + err = parse_flow_nlattrs(encap, a,
>> + &key_attrs,
>> + log);
>> + if (err)
>> + return err;
>> + }
> Can you call this function from parse_vlan_from_nlattrs()? This will
> eliminate following call site too.
>
>> } else if (!tci) {
>> /* Corner case for truncated 802.1Q header. */
>> if (nla_len(encap)) {
>> @@ -1188,10 +1294,21 @@ int ovs_nla_get_match(struct net *net, struct sw_flow_match *match,
>> if (eth_type == htons(0xffff)) {
>> mask_attrs &= ~(1 << OVS_KEY_ATTR_ETHERTYPE);
>> encap = a[OVS_KEY_ATTR_ENCAP];
>> - err = parse_flow_mask_nlattrs(encap, a,
>> - &mask_attrs, log);
>> + err = parse_vlan_from_nlattrs(&encap, match,
>> + &mask_attrs,
>> + &i_encap_valid,
>> + a, true, log);
>> if (err)
>> goto free_newmask;
>> +
>> + if (i_encap_valid) {
>> + err =
>> + parse_flow_mask_nlattrs(encap, a,
>> + &mask_attrs,
>> + log);
>> + if (err)
>> + goto free_newmask;
>> + }
>> } else {
>> OVS_NLERR(log, "VLAN frames must have an exact match on the TPID (mask=%x).",
>> ntohs(eth_type));
>> @@ -1320,6 +1437,7 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
>> {
>> struct ovs_key_ethernet *eth_key;
>> struct nlattr *nla, *encap;
>> + struct nlattr *in_encap = NULL;
>>
>> if (nla_put_u32(skb, OVS_KEY_ATTR_RECIRC_ID, output->recirc_id))
>> goto nla_put_failure;
>> @@ -1368,17 +1486,42 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
>> ether_addr_copy(eth_key->eth_src, output->eth.src);
>> ether_addr_copy(eth_key->eth_dst, output->eth.dst);
>>
>> - if (swkey->eth.tci || swkey->eth.type == htons(ETH_P_8021Q)) {
>> + if (swkey->eth.tci || eth_type_vlan(swkey->eth.type)) {
>> __be16 eth_type;
>> - eth_type = !is_mask ? htons(ETH_P_8021Q) : htons(0xffff);
>> +
>> + if (swkey->eth.cvlan.ctci ||
>> + eth_type_vlan(swkey->eth.cvlan.c_tpid))
>> + eth_type = !is_mask ? htons(ETH_P_8021AD) :
>> + htons(0xffff);
>> + else
>> + eth_type = !is_mask ? htons(ETH_P_8021Q) :
>> + htons(0xffff);
>> +
> Here we can directly dump output->eth.type to netlink. No need to
> check for inner encap.
The eth.type is set to the inner encapsulated protocol not to the tpid.
We don't "know" what the outer tpid so I assume it is 802.1Q. To address
this situation, do you think I should add the outer tpid to sw_flow_key?
Also see comment above in flow.h.
>
>> if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE, eth_type) ||
>> nla_put_be16(skb, OVS_KEY_ATTR_VLAN, output->eth.tci))
>> goto nla_put_failure;
>> encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
>> if (!swkey->eth.tci)
>> goto unencap;
>> - } else
>> + if (swkey->eth.cvlan.ctci || eth_type_vlan(swkey->eth.type)) {
>> + __be16 eth_type;
>> +
>> + /* Customer tci is nested but uses same key attribute.
>> + */
>> + eth_type = !is_mask ? htons(ETH_P_8021Q) :
>> + htons(0xffff);
>
> We can just dump eth_type from output key into netlink attribute
> rather than deriving it from other values.
>
>> + if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE,
>> + eth_type) ||
>> + nla_put_be16(skb, OVS_KEY_ATTR_VLAN,
>> + output->eth.cvlan.ctci))
>> + goto nla_put_failure;
>> + in_encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
>> + if (!swkey->eth.cvlan.ctci)
>> + goto unencap;
>> + }
>> + } else {
>> encap = NULL;
>> + }
>>
>> if (swkey->eth.type == htons(ETH_P_802_2)) {
>> /*
>> @@ -1525,6 +1668,8 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
>> unencap:
>> if (encap)
>> nla_nest_end(skb, encap);
>> + if (in_encap)
>> + nla_nest_end(skb, in_encap);
>>
>> return 0;
>>
>> @@ -2174,7 +2319,8 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
>>
>> case OVS_ACTION_ATTR_PUSH_VLAN:
>> vlan = nla_data(a);
>> - if (vlan->vlan_tpid != htons(ETH_P_8021Q))
>> + if ((vlan->vlan_tpid != htons(ETH_P_8021Q)) &&
>> + (vlan->vlan_tpid != htons(ETH_P_8021AD)))
>> return -EINVAL;
>
> This is open coded negative eth_type_vlan() function.
>
> You also need to update packet_length() in vport-netdev.c
>
--
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