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Message-ID: <20191025023400.GA2564@martin-VirtualBox>
Date: Fri, 25 Oct 2019 08:04:00 +0530
From: Martin Varghese <martinvarghesenokia@...il.com>
To: William Tu <u9012063@...il.com>
Cc: netdev@...r.kernel.org, pshelar@....org, davem@...emloft.net,
scott.drennan@...ia.com, jbenc@...hat.com,
martin.varghese@...ia.com
Subject: Re: [PATCH v2] Change in Openvswitch to support MPLS label depth of
3 in ingress direction
On Thu, Oct 24, 2019 at 01:47:40PM -0700, William Tu wrote:
> On Sun, Oct 20, 2019 at 07:41:42PM +0530, Martin Varghese wrote:
> > From: Martin Varghese <martin.varghese@...ia.com>
> >
> > The openvswitch was supporting a MPLS label depth of 1 in the ingress
> > direction though the userspace OVS supports a max depth of 3 labels.
> > This change enables openvswitch module to support a max depth of
> > 3 labels in the ingress.
> >
>
> Hi Martin,
> Thanks for the patch. I have one comment below.
>
> > Signed-off-by: Martin Varghese <martin.varghese@...ia.com>
> > ---
> > Changes in v2
> > - Moved MPLS count validation from datapath to configuration.
> > - Fixed set mpls function.
> >
> > net/openvswitch/actions.c | 2 +-
> > net/openvswitch/flow.c | 20 ++++++++++-----
> > net/openvswitch/flow.h | 9 ++++---
> > net/openvswitch/flow_netlink.c | 57 +++++++++++++++++++++++++++++++++---------
> > 4 files changed, 66 insertions(+), 22 deletions(-)
> >
> > diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
> > index 3572e11..f3125d7 100644
> > --- a/net/openvswitch/actions.c
> > +++ b/net/openvswitch/actions.c
> > @@ -199,7 +199,7 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key,
> > if (err)
> > return err;
> >
> > - flow_key->mpls.top_lse = lse;
> > + flow_key->mpls.lse[0] = lse;
> > return 0;
> > }
> >
> > diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
> > index dca3b1e..c101355 100644
> > --- a/net/openvswitch/flow.c
> > +++ b/net/openvswitch/flow.c
> > @@ -699,27 +699,35 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
> > memset(&key->ipv4, 0, sizeof(key->ipv4));
> > }
> > } else if (eth_p_mpls(key->eth.type)) {
> > - size_t stack_len = MPLS_HLEN;
> > + u8 label_count = 1;
> >
> > + memset(&key->mpls, 0, sizeof(key->mpls));
> > skb_set_inner_network_header(skb, skb->mac_len);
> > while (1) {
> > __be32 lse;
> >
> > - error = check_header(skb, skb->mac_len + stack_len);
> > + error = check_header(skb, skb->mac_len +
> > + label_count * MPLS_HLEN);
> > if (unlikely(error))
> > return 0;
> >
> > memcpy(&lse, skb_inner_network_header(skb), MPLS_HLEN);
> >
> > - if (stack_len == MPLS_HLEN)
> > - memcpy(&key->mpls.top_lse, &lse, MPLS_HLEN);
> > + if (label_count <= MPLS_LABEL_DEPTH)
> > + memcpy(&key->mpls.lse[label_count - 1], &lse,
> > + MPLS_HLEN);
> >
> > - skb_set_inner_network_header(skb, skb->mac_len + stack_len);
> > + skb_set_inner_network_header(skb, skb->mac_len +
> > + label_count * MPLS_HLEN);
> > if (lse & htonl(MPLS_LS_S_MASK))
> > break;
> >
> > - stack_len += MPLS_HLEN;
> > + label_count++;
> > }
> > + if (label_count > MPLS_LABEL_DEPTH)
> > + label_count = MPLS_LABEL_DEPTH;
> > +
> > + key->mpls.num_labels_mask = GENMASK(label_count - 1, 0);
>
> > } else if (key->eth.type == htons(ETH_P_IPV6)) {
> > int nh_len; /* IPv6 Header + Extensions */
> >
> > diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
> > index 3e2cc22..d9eccbe 100644
> > --- a/net/openvswitch/flow.h
> > +++ b/net/openvswitch/flow.h
> > @@ -30,6 +30,7 @@ enum sw_flow_mac_proto {
> > MAC_PROTO_ETHERNET,
> > };
> > #define SW_FLOW_KEY_INVALID 0x80
> > +#define MPLS_LABEL_DEPTH 3
> >
> > /* Store options at the end of the array if they are less than the
> > * maximum size. This allows us to get the benefits of variable length
> > @@ -85,9 +86,6 @@ struct sw_flow_key {
> > */
> > union {
> > struct {
> > - __be32 top_lse; /* top label stack entry */
> > - } mpls;
> > - struct {
> > u8 proto; /* IP protocol or lower 8 bits of ARP opcode. */
> > u8 tos; /* IP ToS. */
> > u8 ttl; /* IP TTL/hop limit. */
> > @@ -135,6 +133,11 @@ struct sw_flow_key {
> > } nd;
> > };
> > } ipv6;
> > + struct {
> > + u32 num_labels_mask; /* labels present bitmap of effective length MPLS_LABEL_DEPTH */
>
> Why using a bitmap here? why not just num_labels?
> I saw that you have to convert it using hweight_long()
> to num_labels a couple places below.
>
num_labels will not work when used in flow_key for flow match.
Assume a case where a packet with 3 labels are received and the configured
flow has a match condition for the top most label only.Num_labels cannot be
used in that case
My original patch was with num_labels.And we found that it will not work for
the above case.
Jbenc@...hat.com proposed the idea of num_labels_mask.
Thanks for checking the patch.
> Regards,
> William
>
> > + __be32 lse[MPLS_LABEL_DEPTH]; /* label stack entry */
> > + } mpls;
> > +
> > struct ovs_key_nsh nsh; /* network service header */
> > };
> > struct {
> > diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
> > index d7559c6..21de061 100644
> > --- a/net/openvswitch/flow_netlink.c
> > +++ b/net/openvswitch/flow_netlink.c
> > @@ -424,7 +424,7 @@ size_t ovs_key_attr_size(void)
> > [OVS_KEY_ATTR_DP_HASH] = { .len = sizeof(u32) },
> > [OVS_KEY_ATTR_TUNNEL] = { .len = OVS_ATTR_NESTED,
> > .next = ovs_tunnel_key_lens, },
> > - [OVS_KEY_ATTR_MPLS] = { .len = sizeof(struct ovs_key_mpls) },
> > + [OVS_KEY_ATTR_MPLS] = { .len = OVS_ATTR_VARIABLE },
> > [OVS_KEY_ATTR_CT_STATE] = { .len = sizeof(u32) },
> > [OVS_KEY_ATTR_CT_ZONE] = { .len = sizeof(u16) },
> > [OVS_KEY_ATTR_CT_MARK] = { .len = sizeof(u32) },
> > @@ -1628,10 +1628,25 @@ static int ovs_key_from_nlattrs(struct net *net, struct sw_flow_match *match,
> >
> > if (attrs & (1 << OVS_KEY_ATTR_MPLS)) {
> > const struct ovs_key_mpls *mpls_key;
> > + u32 hdr_len;
> > + u32 label_count, label_count_mask, i;
> >
> > mpls_key = nla_data(a[OVS_KEY_ATTR_MPLS]);
> > - SW_FLOW_KEY_PUT(match, mpls.top_lse,
> > - mpls_key->mpls_lse, is_mask);
> > + hdr_len = nla_len(a[OVS_KEY_ATTR_MPLS]);
> > + label_count = hdr_len / sizeof(struct ovs_key_mpls);
> > +
> > + if (label_count == 0 || label_count > MPLS_LABEL_DEPTH ||
> > + hdr_len % sizeof(struct ovs_key_mpls))
> > + return -EINVAL;
> > +
> > + label_count_mask = GENMASK(label_count - 1, 0);
> > +
> > + for (i = 0 ; i < label_count; i++)
> > + SW_FLOW_KEY_PUT(match, mpls.lse[i],
> > + mpls_key[i].mpls_lse, is_mask);
> > +
> > + SW_FLOW_KEY_PUT(match, mpls.num_labels_mask,
> > + label_count_mask, is_mask);
> >
> > attrs &= ~(1 << OVS_KEY_ATTR_MPLS);
> > }
> > @@ -2114,13 +2129,18 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
> > ether_addr_copy(arp_key->arp_sha, output->ipv4.arp.sha);
> > ether_addr_copy(arp_key->arp_tha, output->ipv4.arp.tha);
> > } else if (eth_p_mpls(swkey->eth.type)) {
> > + u8 i, num_labels;
> > struct ovs_key_mpls *mpls_key;
> >
> > - nla = nla_reserve(skb, OVS_KEY_ATTR_MPLS, sizeof(*mpls_key));
> > + num_labels = hweight_long(output->mpls.num_labels_mask);
> > + nla = nla_reserve(skb, OVS_KEY_ATTR_MPLS,
> > + num_labels * sizeof(*mpls_key));
> > if (!nla)
> > goto nla_put_failure;
> > +
> > mpls_key = nla_data(nla);
> > - mpls_key->mpls_lse = output->mpls.top_lse;
> > + for (i = 0; i < num_labels; i++)
> > + mpls_key[i].mpls_lse = output->mpls.lse[i];
> > }
> >
> > if ((swkey->eth.type == htons(ETH_P_IP) ||
> > @@ -2957,6 +2977,10 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
> > u8 mac_proto = ovs_key_mac_proto(key);
> > const struct nlattr *a;
> > int rem, err;
> > + u32 mpls_label_count = 0;
> > +
> > + if (eth_p_mpls(eth_type))
> > + mpls_label_count = hweight_long(key->mpls.num_labels_mask);
> >
> > nla_for_each_nested(a, attr, rem) {
> > /* Expected argument lengths, (u32)-1 for variable length. */
> > @@ -3065,25 +3089,34 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
> > !eth_p_mpls(eth_type)))
> > return -EINVAL;
> > eth_type = mpls->mpls_ethertype;
> > + mpls_label_count++;
> > break;
> > }
> >
> > - case OVS_ACTION_ATTR_POP_MPLS:
> > + case OVS_ACTION_ATTR_POP_MPLS: {
> > + __be16 proto;
> > if (vlan_tci & htons(VLAN_CFI_MASK) ||
> > !eth_p_mpls(eth_type))
> > return -EINVAL;
> >
> > - /* Disallow subsequent L2.5+ set and mpls_pop actions
> > - * as there is no check here to ensure that the new
> > - * eth_type is valid and thus set actions could
> > - * write off the end of the packet or otherwise
> > - * corrupt it.
> > + /* Disallow subsequent L2.5+ set actions as there is
> > + * no check here to ensure that the new eth type is
> > + * valid and thus set actions could write off the
> > + * end of the packet or otherwise corrupt it.
> > *
> > * Support for these actions is planned using packet
> > * recirculation.
> > */
> > - eth_type = htons(0);
> > + proto = nla_get_be16(a);
> > + mpls_label_count--;
> > +
> > + if (!eth_p_mpls(proto) || !mpls_label_count)
> > + eth_type = htons(0);
> > + else
> > + eth_type = proto;
> > +
> > break;
> > + }
> >
> > case OVS_ACTION_ATTR_SET:
> > err = validate_set(a, key, sfa,
> > --
> > 1.8.3.1
> >
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