Allow datapath to recognize and extract MPLS labels into flow keys
and execute actions which push, pop, and set labels on packets.
Based heavily on work by Leo Alterman.
Cc: Leo Alterman <lalter...@nicira.com>
Signed-off-by: Simon Horman <ho...@verge.net.au>
---
v2.2
* Call skb_reset_mac_header() in skb_cb_set_mpls_stack()
eth_hdr(skb) is non-NULL when called in skb_cb_set_mpls_stack().
* Add a call to skb_cb_set_mpls_stack() in ovs_packet_cmd_execute().
I apologise that I have mislaid my notes on this but
it avoids a kernel panic. I can investigate again if necessary.
* Use struct ovs_action_push_mpls instead of
__be16 to decode OVS_ACTION_ATTR_PUSH_MPLS in validate_actions(). This is
consistent with the data format for the attribute.
* Indentation fix in skb_cb_mpls_stack(). [cosmetic]
v2.1
* Manual rebase
Previous version(s) by Leo Alterman
---
datapath/actions.c | 81 +++++++++++++++++++++++++++++++++++++++++++
datapath/datapath.c | 61 ++++++++++++++++++++++++++++++++
datapath/datapath.h | 8 +++++
datapath/flow.c | 30 ++++++++++++++++
datapath/flow.h | 7 ++++
datapath/vport.c | 2 ++
include/linux/openvswitch.h | 32 +++++++++++++++++
7 files changed, 221 insertions(+)
diff --git a/datapath/actions.c b/datapath/actions.c
index ec9b595..c1d1a7f 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 accordingly. */
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 a6915fb..8ff244c 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -74,6 +74,43 @@ 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;
+
+ skb_reset_mac_header(skb);
+
+ 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;
+}
+
+ptrdiff_t skb_cb_mpls_stack_offset(const struct sk_buff *skb)
+{
+ return OVS_CB(skb)->mpls_stack;
+}
+
/**
* DOC: Locking:
*
@@ -663,12 +700,17 @@ 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 +733,23 @@ static int validate_actions(const struct nlattr *attr,
return -EINVAL;
break;
+ 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;
@@ -805,6 +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;
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 02c563a..eb3fe49 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 dc7adfa..0ae4801 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;
+ 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 */
+};
+
+/**
* 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_*. */
--
1.7.10.4
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