On Wed, Oct 03, 2012 at 12:17:16PM -0700, Jesse Gross wrote:
> From: Leo Alterman <[email protected]>
>
> Allow datapath to recognize and extract MPLS labels into flow keys
> and execute actions which push, pop, and set labels on packets.
Hi,
I now have this code working in conjunction with a modified
version of Ravi's user-space code. I will post a patchset which
works under for my light testing shortly.
What follows are details of changes I made to this patch in
order for it to work in my setup.
Firstly,
I needed the following to unsure that
diff --git a/datapath/datapath.c b/datapath/datapath.c
index 79c50af..8ff244c 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -861,6 +864,8 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb,
struct genl_info *info)
OVS_CB(packet)->flow = flow;
packet->priority = flow->key.phy.priority;
+ skb_cb_set_mpls_stack(packet);
+
rcu_read_lock();
dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
err = -ENODEV;
The rest of my proposed changes are inline below.
>
> Signed-off-by: Leo Alterman <[email protected]>
> --
> I haven't reviewed this but hopefully it can be used a good starting point.
> ---
> datapath/actions.c | 81
> +++++++++++++++++++++++++++++++++++++++++++
> datapath/datapath.c | 56 ++++++++++++++++++++++++++++++
> datapath/datapath.h | 8 +++++
> datapath/flow.c | 30 ++++++++++++++++
> datapath/flow.h | 7 ++++
> datapath/vport.c | 2 ++
> include/linux/openvswitch.h | 32 +++++++++++++++++
> 7 files changed, 216 insertions(+)
>
> diff --git a/datapath/actions.c b/datapath/actions.c
> index 208f260..a199125 100644
> --- a/datapath/actions.c
> +++ b/datapath/actions.c
> @@ -47,6 +47,67 @@ static int make_writable(struct sk_buff *skb, int
> write_len)
> return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
> }
>
> +static __be16 get_ethertype(const struct sk_buff *skb)
> +{
> + struct ethhdr *hdr = (struct ethhdr *)(skb_cb_mpls_stack(skb) -
> ETH_HLEN);
> + return hdr->h_proto;
> +}
> +
> +static void set_ethertype(struct sk_buff *skb, const __be16 ethertype)
> +{
> + struct ethhdr *hdr = (struct ethhdr *)(skb_cb_mpls_stack(skb) -
> ETH_HLEN);
> + hdr->h_proto = ethertype;
> +}
> +
> +static int push_mpls(struct sk_buff *skb, const struct ovs_action_push_mpls
> *mpls)
> +{
> + u32 l2_size;
> + __be32 *new_mpls_label;
> +
> + if (skb_cow_head(skb, MPLS_HLEN) < 0) {
> + kfree_skb(skb);
> + return -ENOMEM;
> + }
> +
> + l2_size = skb_cb_mpls_stack_offset(skb);
> + skb_push(skb, MPLS_HLEN);
> + memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb), l2_size);
> + skb_reset_mac_header(skb);
> +
> + new_mpls_label = (__be32 *)(skb_mac_header(skb) + l2_size);
> + *new_mpls_label = mpls->mpls_label;
> +
> + set_ethertype(skb, mpls->mpls_ethertype);
> + return 0;
> +}
> +
> +static int pop_mpls(struct sk_buff *skb, const __be16 *ethertype)
> +{
> + __be16 current_ethertype = get_ethertype(skb);
> + if (current_ethertype == htons(ETH_P_MPLS_UC) ||
> + current_ethertype == htons(ETH_P_MPLS_MC)) {
> + u32 l2_size = skb_cb_mpls_stack_offset(skb);
> +
> + memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
> l2_size);
> +
> + skb_pull(skb, MPLS_HLEN);
> + skb_reset_mac_header(skb);
> +
> + set_ethertype(skb, *ethertype);
> + }
> + return 0;
> +}
> +
> +static int set_mpls(struct sk_buff *skb, const __be32 *mpls_label)
> +{
> + __be16 current_ethertype = get_ethertype(skb);
> + if (current_ethertype == htons(ETH_P_MPLS_UC) ||
> + current_ethertype == htons(ETH_P_MPLS_MC)) {
> + memcpy(skb_cb_mpls_stack(skb), mpls_label, sizeof(__be32));
> + }
> + return 0;
> +}
> +
> /* remove VLAN header from packet and update csum accrodingly. */
> static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
> {
> @@ -100,6 +161,9 @@ static int pop_vlan(struct sk_buff *skb)
> return err;
>
> __vlan_hwaccel_put_tag(skb, ntohs(tci));
> +
> + /* update pointer to MPLS label stack */
> + skb_cb_set_mpls_stack(skb);
> return 0;
> }
>
> @@ -120,6 +184,9 @@ static int push_vlan(struct sk_buff *skb, const struct
> ovs_action_push_vlan *vla
>
> }
> __vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
> +
> + /* update pointer to MPLS label stack */
> + skb_cb_set_mpls_stack(skb);
> return 0;
> }
>
> @@ -396,6 +463,20 @@ static int do_execute_actions(struct datapath *dp,
> struct sk_buff *skb,
> output_userspace(dp, skb, a);
> break;
>
> + case OVS_ACTION_ATTR_PUSH_MPLS:
> + err = push_mpls(skb, nla_data(a));
> + if (unlikely(err)) /* skb already freed. */
> + return err;
> + break;
> +
> + case OVS_ACTION_ATTR_POP_MPLS:
> + err = pop_mpls(skb, nla_data(a));
> + break;
> +
> + case OVS_ACTION_ATTR_SET_MPLS:
> + err = set_mpls(skb, nla_data(a));
> + break;
> +
> case OVS_ACTION_ATTR_PUSH_VLAN:
> err = push_vlan(skb, nla_data(a));
> if (unlikely(err)) /* skb already freed. */
> diff --git a/datapath/datapath.c b/datapath/datapath.c
> index c83ce16..91b70bb 100644
> --- a/datapath/datapath.c
> +++ b/datapath/datapath.c
> @@ -74,6 +74,41 @@ int ovs_net_id __read_mostly;
> int (*ovs_dp_ioctl_hook)(struct net_device *dev, struct ifreq *rq, int cmd);
> EXPORT_SYMBOL(ovs_dp_ioctl_hook);
>
> +void skb_cb_set_mpls_stack(struct sk_buff *skb)
> +{
> + struct ethhdr *eth;
> + int nh_ofs;
> + __be16 dl_type = 0;
> +
> + eth = eth_hdr(skb);
> + nh_ofs = sizeof(struct ethhdr);
> + if (likely(eth->h_proto >= htons(ETH_TYPE_MIN))) {
> + dl_type = eth->h_proto;
> +
> + while (dl_type == htons(ETH_P_8021Q) &&
> + skb->len >= nh_ofs + sizeof(struct vlan_hdr)) {
> + struct vlan_hdr *vh = (struct vlan_hdr*)(skb->data +
> nh_ofs);
> + dl_type = vh->h_vlan_encapsulated_proto;
> + nh_ofs += sizeof(struct vlan_hdr);
> + }
> +
> + OVS_CB(skb)->mpls_stack = nh_ofs;
> + } else {
> + OVS_CB(skb)->mpls_stack = 0;
> + }
> +}
> +
> +unsigned char *skb_cb_mpls_stack(const struct sk_buff *skb)
> +{
> + return OVS_CB(skb)->mpls_stack ?
> + skb_mac_header(skb) +
> OVS_CB(skb)->mpls_stack : 0;
The indentation on the line above is suboptimal.
> +}
> +
> +ptrdiff_t skb_cb_mpls_stack_offset(const struct sk_buff *skb)
> +{
> + return OVS_CB(skb)->mpls_stack;
> +}
> +
> /**
> * DOC: Locking:
> *
> @@ -663,12 +698,17 @@ static int validate_actions(const struct nlattr *attr,
> static const u32 action_lens[OVS_ACTION_ATTR_MAX + 1] = {
> [OVS_ACTION_ATTR_OUTPUT] = sizeof(u32),
> [OVS_ACTION_ATTR_USERSPACE] = (u32)-1,
> + [OVS_ACTION_ATTR_PUSH_MPLS] = sizeof(struct
> ovs_action_push_mpls),
> + [OVS_ACTION_ATTR_POP_MPLS] = sizeof(__be16),
> + [OVS_ACTION_ATTR_SET_MPLS] = sizeof(__be32),
> [OVS_ACTION_ATTR_PUSH_VLAN] = sizeof(struct
> ovs_action_push_vlan),
> [OVS_ACTION_ATTR_POP_VLAN] = 0,
> [OVS_ACTION_ATTR_SET] = (u32)-1,
> [OVS_ACTION_ATTR_SAMPLE] = (u32)-1
> };
> const struct ovs_action_push_vlan *vlan;
> + __be16 mpls_ethertype;
> + __be32 mpls_label;
> int type = nla_type(a);
>
> if (type > OVS_ACTION_ATTR_MAX ||
> @@ -691,6 +731,22 @@ static int validate_actions(const struct nlattr *attr,
> return -EINVAL;
> break;
>
> + case OVS_ACTION_ATTR_PUSH_MPLS:
> + mpls_ethertype = nla_get_be16(a);
> + if (mpls_ethertype != htons(ETH_P_MPLS_UC) &&
> + mpls_ethertype != htons(ETH_P_MPLS_MC))
> + return -EINVAL;
> + break;
The case above does not seem to function because the attribute
is a struct struct ovs_action_push_mpls where the ether_type is
preceded by a 32bit label.
The following seems to work for me:
case OVS_ACTION_ATTR_PUSH_MPLS: {
const struct ovs_action_push_mpls *mpls = nla_data(a);
if (mpls->mpls_ethertype != htons(ETH_P_MPLS_UC) &&
mpls->mpls_ethertype != htons(ETH_P_MPLS_MC))
return -EINVAL;
break;
}
> +
> + case OVS_ACTION_ATTR_POP_MPLS:
> + break;
> +
> + case OVS_ACTION_ATTR_SET_MPLS:
> + mpls_label = nla_get_be32(a);
> + if (mpls_label == htonl(0)) {
> + return -EINVAL;
> + }
> + break;
>
> case OVS_ACTION_ATTR_POP_VLAN:
> break;
> diff --git a/datapath/datapath.h b/datapath/datapath.h
> index affbf0e..1801ccd 100644
> --- a/datapath/datapath.h
> +++ b/datapath/datapath.h
> @@ -97,6 +97,9 @@ 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
> + * packet is not being tunneled.
> + * @mpls_stack: Offset of the packet's MPLS stack from the beginning of the
> + * ethernet frame. It is 0 if no MPLS stack is present.
> * @ip_summed: Consistently stores L4 checksumming status across different
> * kernel versions.
> * @csum_start: Stores the offset from which to start checksumming
> independent
> @@ -108,6 +111,7 @@ struct datapath {
> struct ovs_skb_cb {
> struct sw_flow *flow;
> __be64 tun_id;
> + ptrdiff_t mpls_stack;
> #ifdef NEED_CSUM_NORMALIZE
> enum csum_type ip_summed;
> u16 csum_start;
> @@ -192,4 +196,8 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *,
> u32 pid, u32 seq,
> u8 cmd);
>
> int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb);
> +
> +void skb_cb_set_mpls_stack(struct sk_buff *skb);
> +unsigned char *skb_cb_mpls_stack(const struct sk_buff *skb);
> +ptrdiff_t skb_cb_mpls_stack_offset(const struct sk_buff *skb);
> #endif /* datapath.h */
> diff --git a/datapath/flow.c b/datapath/flow.c
> index d07337c..40df8ff 100644
> --- a/datapath/flow.c
> +++ b/datapath/flow.c
> @@ -739,6 +739,14 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port,
> struct sw_flow_key *key,
> key_len = SW_FLOW_KEY_OFFSET(ipv4.arp);
> }
> }
> + } else if (key->eth.type == htons(ETH_P_MPLS_UC) ||
> + key->eth.type == htons(ETH_P_MPLS_MC)) {
> + error = check_header(skb, MPLS_HLEN);
> + if (unlikely(error))
> + goto out;
> +
> + key_len = SW_FLOW_KEY_OFFSET(mpls.top_label);
> + memcpy(&key->mpls.top_label, skb_network_header(skb),
> MPLS_HLEN);
> } else if (key->eth.type == htons(ETH_P_IPV6)) {
> int nh_len; /* IPv6 Header + Extensions */
>
> @@ -836,6 +844,7 @@ const int ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
> [OVS_KEY_ATTR_ETHERNET] = sizeof(struct ovs_key_ethernet),
> [OVS_KEY_ATTR_VLAN] = sizeof(__be16),
> [OVS_KEY_ATTR_ETHERTYPE] = sizeof(__be16),
> + [OVS_KEY_ATTR_MPLS] = sizeof(struct ovs_key_mpls),
> [OVS_KEY_ATTR_IPV4] = sizeof(struct ovs_key_ipv4),
> [OVS_KEY_ATTR_IPV6] = sizeof(struct ovs_key_ipv6),
> [OVS_KEY_ATTR_TCP] = sizeof(struct ovs_key_tcp),
> @@ -1141,6 +1150,17 @@ int ovs_flow_from_nlattrs(struct sw_flow_key *swkey,
> int *key_lenp,
> swkey->ip.proto = ntohs(arp_key->arp_op);
> memcpy(swkey->ipv4.arp.sha, arp_key->arp_sha, ETH_ALEN);
> memcpy(swkey->ipv4.arp.tha, arp_key->arp_tha, ETH_ALEN);
> + } else if (swkey->eth.type == htons(ETH_P_MPLS_UC) ||
> + swkey->eth.type == htons(ETH_P_MPLS_MC)) {
> + const struct ovs_key_mpls *mpls_key;
> +
> + if (!(attrs & (1 << OVS_KEY_ATTR_MPLS)))
> + return -EINVAL;
> + attrs &= ~(1 << OVS_KEY_ATTR_MPLS);
> +
> + key_len = SW_FLOW_KEY_OFFSET(mpls.top_label);
> + mpls_key = nla_data(a[OVS_KEY_ATTR_MPLS]);
> + swkey->mpls.top_label = mpls_key->mpls_top_label;
> }
>
> if (attrs)
> @@ -1284,6 +1304,16 @@ int ovs_flow_to_nlattrs(const struct sw_flow_key
> *swkey, struct sk_buff *skb)
> arp_key->arp_op = htons(swkey->ip.proto);
> memcpy(arp_key->arp_sha, swkey->ipv4.arp.sha, ETH_ALEN);
> memcpy(arp_key->arp_tha, swkey->ipv4.arp.tha, ETH_ALEN);
> + } else if (swkey->eth.type == htons(ETH_P_MPLS_UC) ||
> + swkey->eth.type == htons(ETH_P_MPLS_MC)) {
> + struct ovs_key_mpls *mpls_key;
> +
> + nla = nla_reserve(skb, OVS_KEY_ATTR_MPLS, sizeof(*mpls_key));
> + if (!nla)
> + goto nla_put_failure;
> + mpls_key = nla_data(nla);
> + memset(mpls_key, 0, sizeof(struct ovs_key_mpls));
> + mpls_key->mpls_top_label = swkey->mpls.top_label;
> }
>
> if ((swkey->eth.type == htons(ETH_P_IP) ||
> diff --git a/datapath/flow.h b/datapath/flow.h
> index 5be481e..c18183b 100644
> --- a/datapath/flow.h
> +++ b/datapath/flow.h
> @@ -53,6 +53,9 @@ struct sw_flow_key {
> __be16 type; /* Ethernet frame type. */
> } eth;
> struct {
> + __be32 top_label; /* 0 if no MPLS, top label from stack
> otherwise */
> + } mpls;
> + struct {
> u8 proto; /* IP protocol or lower 8 bits of ARP
> opcode. */
> u8 tos; /* IP ToS. */
> u8 ttl; /* IP TTL/hop limit. */
> @@ -126,6 +129,10 @@ struct arp_eth_header {
> unsigned char ar_tip[4]; /* target IP address */
> } __packed;
>
> +#define ETH_TYPE_MIN 0x600
> +
> +#define MPLS_HLEN 4
> +
> int ovs_flow_init(void);
> void ovs_flow_exit(void);
>
> diff --git a/datapath/vport.c b/datapath/vport.c
> index 172261a..0664e4c 100644
> --- a/datapath/vport.c
> +++ b/datapath/vport.c
> @@ -464,6 +464,8 @@ void ovs_vport_receive(struct vport *vport, struct
> sk_buff *skb)
> if (!(vport->ops->flags & VPORT_F_TUN_ID))
> OVS_CB(skb)->tun_id = 0;
I have encountered situations where skb_cb_set_mpls_stack() panics
because eth_hdr(skb) returns NULL.
I'm unsure if this is the best fix, but adding the following here
seems to resolve the problem that I observed.
skb_cb_set_mpls_stack(skb);
>
> + skb_cb_set_mpls_stack(skb);
> +
> ovs_dp_process_received_packet(vport, skb);
> }
>
> diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
> index f5c9cca..78960d1 100644
> --- a/include/linux/openvswitch.h
> +++ b/include/linux/openvswitch.h
> @@ -278,6 +278,7 @@ enum ovs_key_attr {
> OVS_KEY_ATTR_ICMPV6, /* struct ovs_key_icmpv6 */
> OVS_KEY_ATTR_ARP, /* struct ovs_key_arp */
> OVS_KEY_ATTR_ND, /* struct ovs_key_nd */
> + OVS_KEY_ATTR_MPLS, /* struct ovs_key_mpls */
> OVS_KEY_ATTR_TUN_ID = 63, /* be64 tunnel ID */
> __OVS_KEY_ATTR_MAX
> };
> @@ -307,6 +308,10 @@ struct ovs_key_ethernet {
> __u8 eth_dst[6];
> };
>
> +struct ovs_key_mpls {
> + __be32 mpls_top_label;
> +};
> +
> struct ovs_key_ipv4 {
> __be32 ipv4_src;
> __be32 ipv4_dst;
> @@ -437,6 +442,20 @@ enum ovs_userspace_attr {
> #define OVS_USERSPACE_ATTR_MAX (__OVS_USERSPACE_ATTR_MAX - 1)
>
> /**
> + * struct ovs_action_push_mpls - %OVS_ACTION_ATTR_PUSH_MPLS action argument.
> + * @mpls_label: MPLS label to push.
> + * @mpls_ethertype: Ethertype to set in the encapsulating ethernet frame.
> + *
> + * The only values @mpls_ethertype should ever be given are %ETH_P_MPLS_UC
> and
> + * %ETH_P_MPLS_MC, indicating MPLS unicast or multicast. Any other values
> would
> + * produce a corrupt packet.
> + */
> +struct ovs_action_push_mpls {
> + __be32 mpls_label;
> + __be16 mpls_ethertype; /* Either %ETH_P_MPLS_UC or %ETH_P_MPLS_MC */
I believe that this structure will be padded out to be 64 bytes
so perhaps it would be worth adding a pad or zero element value
to make it clear that some care needs to be taken there?
__be16 zero;
> +};
> +
> +/**
> * struct ovs_action_push_vlan - %OVS_ACTION_ATTR_PUSH_VLAN action argument.
> * @vlan_tpid: Tag protocol identifier (TPID) to push.
> * @vlan_tci: Tag control identifier (TCI) to push. The CFI bit must be set
> @@ -461,6 +480,16 @@ struct ovs_action_push_vlan {
> * @OVS_ACTION_ATTR_SET: Replaces the contents of an existing header. The
> * single nested %OVS_KEY_ATTR_* attribute specifies a header to modify and
> its
> * value.
> + * @OVS_ACTION_ATTR_PUSH_MPLS: Push a new MPLS label onto the top of the
> packet
> + * MPLS stack. Set the ethertype of the encapsulating frame to either
> + * %ETH_P_MPLS_UC or %ETH_P_MPLS_MC to indicate the new packet contents.
> + * @OVS_ACTION_ATTR_POP_MPLS: Pop an MPLS label off of the packet's MPLS
> stack.
> + * Set the encapsulating frame's ethertype to indicate the new packet
> contents
> + * (this could potentially still be %ETH_P_MPLS_* if there are remaining MPLS
> + * labels). If there are no MPLS labels as determined by ethertype, no
> action
> + * is taken.
> + * @OVS_ACTION_ATTR_SET_MPLS: Set the value of the top-most label in the MPLS
> + * label stack. If there are no MPLS labels in the packet, no action is
> taken.
> * @OVS_ACTION_ATTR_PUSH_VLAN: Push a new outermost 802.1Q header onto the
> * packet.
> * @OVS_ACTION_ATTR_POP_VLAN: Pop the outermost 802.1Q header off the packet.
> @@ -477,6 +506,9 @@ enum ovs_action_attr {
> OVS_ACTION_ATTR_OUTPUT, /* u32 port number. */
> OVS_ACTION_ATTR_USERSPACE, /* Nested OVS_USERSPACE_ATTR_*. */
> OVS_ACTION_ATTR_SET, /* One nested OVS_KEY_ATTR_*. */
> + OVS_ACTION_ATTR_PUSH_MPLS, /* struct ovs_action_push_mpls. */
> + OVS_ACTION_ATTR_POP_MPLS, /* __be16 ethertype. */
> + OVS_ACTION_ATTR_SET_MPLS, /* __be32 MPLS label */
> OVS_ACTION_ATTR_PUSH_VLAN, /* struct ovs_action_push_vlan. */
> OVS_ACTION_ATTR_POP_VLAN, /* No argument. */
> OVS_ACTION_ATTR_SAMPLE, /* Nested OVS_SAMPLE_ATTR_*. */
> --
> 1.7.9.5
>
> _______________________________________________
> dev mailing list
> [email protected]
> http://openvswitch.org/mailman/listinfo/dev
>
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