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Date: Fri, 21 Nov 2014 19:05:53 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: Pravin Shelar <pshelar@...ira.com>
Cc: netdev <netdev@...r.kernel.org>,
David Miller <davem@...emloft.net>,
Jamal Hadi Salim <jhs@...atatu.com>,
Tom Herbert <therbert@...gle.com>,
Eric Dumazet <edumazet@...gle.com>,
Willem de Bruijn <willemb@...gle.com>,
Daniel Borkmann <dborkman@...hat.com>, mst@...hat.com,
fw@...len.de, Paul.Durrant@...rix.com, Thomas Graf <tgraf@...g.ch>,
Cong Wang <cwang@...pensource.com>
Subject: Re: [patch net-next v4 8/9] net: move vlan pop/push functions into
common code
Fri, Nov 21, 2014 at 05:11:39PM CET, pshelar@...ira.com wrote:
>On Wed, Nov 19, 2014 at 5:05 AM, Jiri Pirko <jiri@...nulli.us> wrote:
>> So it can be used from out of openvswitch code.
>> Did couple of cosmetic changes on the way, namely variable naming and
>> adding support for 8021AD proto.
>>
>> Signed-off-by: Jiri Pirko <jiri@...nulli.us>
>> ---
>>
>> v3->v4:
>> - don't try to be smart and copy skb->mac_len manipulation as it is. It can be
>> adjusted later on.
>
>I am fine with moving this code to generic library, as long as we can
>adjust the mac_len as offset for MPLS header, otherwise this breaks
>MPLS support.
Pravin, I'm just moving the code without changing it in this aspect.
Maybe I'm missing something but can you tell me what you see wrong?
Thanks.
>
>> - fix error path in do_execute_actions as suggested by Pravin
>> v2->v3:
>> - used previously introduced __vlan_insert_tag helper
>> - used skb_push/pull to get skb->data into needed point
>> - fixed skb->mac_len computation in skb_vlan_push pointed out by Pravin
>> v1->v2:
>> - adjusted to fix recent ovs changes
>> - included change to use make_writable suggested by Eric
>>
>> include/linux/skbuff.h | 2 +
>> net/core/skbuff.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++
>> net/openvswitch/actions.c | 86 +++++-------------------------------------
>> 3 files changed, 106 insertions(+), 77 deletions(-)
>>
>> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
>> index e045516..78c299f 100644
>> --- a/include/linux/skbuff.h
>> +++ b/include/linux/skbuff.h
>> @@ -2679,6 +2679,8 @@ unsigned int skb_gso_transport_seglen(const struct sk_buff *skb);
>> struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
>> struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
>> int skb_ensure_writable(struct sk_buff *skb, int write_len);
>> +int skb_vlan_pop(struct sk_buff *skb);
>> +int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
>>
>> struct skb_checksum_ops {
>> __wsum (*update)(const void *mem, int len, __wsum wsum);
>> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
>> index d11bbe0..c906c5f 100644
>> --- a/net/core/skbuff.c
>> +++ b/net/core/skbuff.c
>> @@ -4163,6 +4163,101 @@ int skb_ensure_writable(struct sk_buff *skb, int write_len)
>> }
>> EXPORT_SYMBOL(skb_ensure_writable);
>>
>> +/* remove VLAN header from packet and update csum accordingly. */
>> +static int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci)
>> +{
>> + struct vlan_hdr *vhdr;
>> + unsigned int offset = skb->data - skb_mac_header(skb);
>> + int err;
>> +
>> + __skb_push(skb, offset);
>> + err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
>> + if (unlikely(err))
>> + goto pull;
>> +
>> + skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
>> +
>> + vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
>> + *vlan_tci = ntohs(vhdr->h_vlan_TCI);
>> +
>> + memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
>> + __skb_pull(skb, VLAN_HLEN);
>> +
>> + vlan_set_encap_proto(skb, vhdr);
>> + skb->mac_header += VLAN_HLEN;
>> +
>> + if (skb_network_offset(skb) < ETH_HLEN)
>> + skb_set_network_header(skb, ETH_HLEN);
>> +
>> + skb_reset_mac_len(skb);
>> +pull:
>> + __skb_pull(skb, offset);
>> +
>> + return err;
>> +}
>> +
>> +int skb_vlan_pop(struct sk_buff *skb)
>> +{
>> + u16 vlan_tci;
>> + __be16 vlan_proto;
>> + int err;
>> +
>> + if (likely(vlan_tx_tag_present(skb))) {
>> + skb->vlan_tci = 0;
>> + } else {
>> + if (unlikely((skb->protocol != htons(ETH_P_8021Q) &&
>> + skb->protocol != htons(ETH_P_8021AD)) ||
>> + skb->len < VLAN_ETH_HLEN))
>> + return 0;
>> +
>> + err = __skb_vlan_pop(skb, &vlan_tci);
>> + if (err)
>> + return err;
>> + }
>> + /* move next vlan tag to hw accel tag */
>> + if (likely((skb->protocol != htons(ETH_P_8021Q) &&
>> + skb->protocol != htons(ETH_P_8021AD)) ||
>> + skb->len < VLAN_ETH_HLEN))
>> + return 0;
>> +
>> + vlan_proto = skb->protocol;
>> + err = __skb_vlan_pop(skb, &vlan_tci);
>> + if (unlikely(err))
>> + return err;
>> +
>> + __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
>> + return 0;
>> +}
>> +EXPORT_SYMBOL(skb_vlan_pop);
>> +
>> +int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
>> +{
>> + if (vlan_tx_tag_present(skb)) {
>> + unsigned int offset = skb->data - skb_mac_header(skb);
>> + int err;
>> +
>> + /* __vlan_insert_tag expect skb->data pointing to mac header.
>> + * So change skb->data before calling it and change back to
>> + * original position later
>> + */
>> + __skb_push(skb, offset);
>> + err = __vlan_insert_tag(skb, skb->vlan_proto,
>> + vlan_tx_tag_get(skb));
>> + if (err)
>> + return err;
>> + skb->protocol = skb->vlan_proto;
>> + skb->mac_len += VLAN_HLEN;
>> + __skb_pull(skb, offset);
>> +
>> + if (skb->ip_summed == CHECKSUM_COMPLETE)
>> + skb->csum = csum_add(skb->csum, csum_partial(skb->data
>> + + (2 * ETH_ALEN), VLAN_HLEN, 0));
>> + }
>> + __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
>> + return 0;
>> +}
>> +EXPORT_SYMBOL(skb_vlan_push);
>> +
>> /**
>> * alloc_skb_with_frags - allocate skb with page frags
>> *
>> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
>> index 7ffa377..4e05ea1 100644
>> --- a/net/openvswitch/actions.c
>> +++ b/net/openvswitch/actions.c
>> @@ -206,93 +206,27 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *key,
>> return 0;
>> }
>>
>> -/* remove VLAN header from packet and update csum accordingly. */
>> -static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
>> -{
>> - struct vlan_hdr *vhdr;
>> - int err;
>> -
>> - err = skb_ensure_writable(skb, VLAN_ETH_HLEN);
>> - if (unlikely(err))
>> - return err;
>> -
>> - skb_postpull_rcsum(skb, skb->data + (2 * ETH_ALEN), VLAN_HLEN);
>> -
>> - vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
>> - *current_tci = vhdr->h_vlan_TCI;
>> -
>> - memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
>> - __skb_pull(skb, VLAN_HLEN);
>> -
>> - vlan_set_encap_proto(skb, vhdr);
>> - skb->mac_header += VLAN_HLEN;
>> -
>> - if (skb_network_offset(skb) < ETH_HLEN)
>> - skb_set_network_header(skb, ETH_HLEN);
>> -
>> - /* Update mac_len for subsequent MPLS actions */
>> - skb_reset_mac_len(skb);
>> - return 0;
>> -}
>> -
>> static int pop_vlan(struct sk_buff *skb, struct sw_flow_key *key)
>> {
>> - __be16 tci;
>> int err;
>>
>> - if (likely(vlan_tx_tag_present(skb))) {
>> - skb->vlan_tci = 0;
>> - } else {
>> - if (unlikely(skb->protocol != htons(ETH_P_8021Q) ||
>> - skb->len < VLAN_ETH_HLEN))
>> - return 0;
>> -
>> - err = __pop_vlan_tci(skb, &tci);
>> - if (err)
>> - return err;
>> - }
>> - /* move next vlan tag to hw accel tag */
>> - if (likely(skb->protocol != htons(ETH_P_8021Q) ||
>> - skb->len < VLAN_ETH_HLEN)) {
>> + err = skb_vlan_pop(skb);
>> + if (vlan_tx_tag_present(skb))
>> + invalidate_flow_key(key);
>> + else
>> key->eth.tci = 0;
>> - return 0;
>> - }
>> -
>> - invalidate_flow_key(key);
>> - err = __pop_vlan_tci(skb, &tci);
>> - if (unlikely(err))
>> - return err;
>> -
>> - __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), ntohs(tci));
>> - return 0;
>> + return err;
>> }
>>
>> static int push_vlan(struct sk_buff *skb, struct sw_flow_key *key,
>> const struct ovs_action_push_vlan *vlan)
>> {
>> - if (unlikely(vlan_tx_tag_present(skb))) {
>> - u16 current_tag;
>> -
>> - /* push down current VLAN tag */
>> - current_tag = vlan_tx_tag_get(skb);
>> -
>> - skb = vlan_insert_tag_set_proto(skb, skb->vlan_proto,
>> - current_tag);
>> - if (!skb)
>> - return -ENOMEM;
>> - /* Update mac_len for subsequent MPLS actions */
>> - skb->mac_len += VLAN_HLEN;
>> -
>> - if (skb->ip_summed == CHECKSUM_COMPLETE)
>> - skb->csum = csum_add(skb->csum, csum_partial(skb->data
>> - + (2 * ETH_ALEN), VLAN_HLEN, 0));
>> -
>> + if (vlan_tx_tag_present(skb))
>> invalidate_flow_key(key);
>> - } else {
>> + else
>> key->eth.tci = vlan->vlan_tci;
>> - }
>> - __vlan_hwaccel_put_tag(skb, vlan->vlan_tpid, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
>> - return 0;
>> + return skb_vlan_push(skb, vlan->vlan_tpid,
>> + ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
>> }
>>
>> static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *key,
>> @@ -858,8 +792,6 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>>
>> case OVS_ACTION_ATTR_PUSH_VLAN:
>> err = push_vlan(skb, key, nla_data(a));
>> - if (unlikely(err)) /* skb already freed. */
>> - return err;
>> break;
>>
>> case OVS_ACTION_ATTR_POP_VLAN:
>> --
>> 1.9.3
>>
--
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