net: Add Open vSwitch kernel components.

Open vSwitch is a multilayer Ethernet switch targeted at virtualized
environments.  In addition to supporting a variety of features
expected in a traditional hardware switch, it enables fine-grained
programmatic extension and flow-based control of the network.
This control is useful in a wide variety of applications but is
particularly important in multi-server virtualization deployments,
which are often characterized by highly dynamic endpoints and the need
to maintain logical abstractions for multiple tenants.

The Open vSwitch datapath provides an in-kernel fast path for packet
forwarding.  It is complemented by a userspace daemon, ovs-vswitchd,
which is able to accept configuration from a variety of sources and
translate it into packet processing rules.

See http://openvswitch.org for more information and userspace
utilities.

Signed-off-by: Jesse Gross <jesse@nicira.com>

1 files changed, 415 insertions, 0 deletions

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
new file mode 100644
index 000000000000..2725d1bdf291
--- /dev/null
+++ b/net/openvswitch/actions.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright (c) 2007-2011 Nicira Networks.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/openvswitch.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/in6.h>
+#include <linux/if_arp.h>
+#include <linux/if_vlan.h>
+#include <net/ip.h>
+#include <net/checksum.h>
+#include <net/dsfield.h>
+
+#include "datapath.h"
+#include "vport.h"
+
+static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
+                        const struct nlattr *attr, int len, bool keep_skb);
+
+static int make_writable(struct sk_buff *skb, int write_len)
+{
+        if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
+                return 0;
+
+        return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
+}
+
+/* remove VLAN header from packet and update csum accrodingly. */
+static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
+{
+        struct vlan_hdr *vhdr;
+        int err;
+
+        err = make_writable(skb, VLAN_ETH_HLEN);
+        if (unlikely(err))
+                return err;
+
+        if (skb->ip_summed == CHECKSUM_COMPLETE)
+                skb->csum = csum_sub(skb->csum, csum_partial(skb->data
+                                        + ETH_HLEN, VLAN_HLEN, 0));
+
+        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;
+        skb_reset_mac_len(skb);
+
+        return 0;
+}
+
+static int pop_vlan(struct sk_buff *skb)
+{
+        __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))
+                return 0;
+
+        err = __pop_vlan_tci(skb, &tci);
+        if (unlikely(err))
+                return err;
+
+        __vlan_hwaccel_put_tag(skb, ntohs(tci));
+        return 0;
+}
+
+static int push_vlan(struct sk_buff *skb, 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);
+
+                if (!__vlan_put_tag(skb, current_tag))
+                        return -ENOMEM;
+
+                if (skb->ip_summed == CHECKSUM_COMPLETE)
+                        skb->csum = csum_add(skb->csum, csum_partial(skb->data
+                                        + ETH_HLEN, VLAN_HLEN, 0));
+
+        }
+        __vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
+        return 0;
+}
+
+static int set_eth_addr(struct sk_buff *skb,
+                        const struct ovs_key_ethernet *eth_key)
+{
+        int err;
+        err = make_writable(skb, ETH_HLEN);
+        if (unlikely(err))
+                return err;
+
+        memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN);
+        memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN);
+
+        return 0;
+}
+
+static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
+                                __be32 *addr, __be32 new_addr)
+{
+        int transport_len = skb->len - skb_transport_offset(skb);
+
+        if (nh->protocol == IPPROTO_TCP) {
+                if (likely(transport_len >= sizeof(struct tcphdr)))
+                        inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
+                                                 *addr, new_addr, 1);
+        } else if (nh->protocol == IPPROTO_UDP) {
+                if (likely(transport_len >= sizeof(struct udphdr)))
+                        inet_proto_csum_replace4(&udp_hdr(skb)->check, skb,
+                                                 *addr, new_addr, 1);
+        }
+
+        csum_replace4(&nh->check, *addr, new_addr);
+        skb->rxhash = 0;
+        *addr = new_addr;
+}
+
+static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
+{
+        csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
+        nh->ttl = new_ttl;
+}
+
+static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
+{
+        struct iphdr *nh;
+        int err;
+
+        err = make_writable(skb, skb_network_offset(skb) +
+                                 sizeof(struct iphdr));
+        if (unlikely(err))
+                return err;
+
+        nh = ip_hdr(skb);
+
+        if (ipv4_key->ipv4_src != nh->saddr)
+                set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
+
+        if (ipv4_key->ipv4_dst != nh->daddr)
+                set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
+
+        if (ipv4_key->ipv4_tos != nh->tos)
+                ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
+
+        if (ipv4_key->ipv4_ttl != nh->ttl)
+                set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
+
+        return 0;
+}
+
+/* Must follow make_writable() since that can move the skb data. */
+static void set_tp_port(struct sk_buff *skb, __be16 *port,
+                         __be16 new_port, __sum16 *check)
+{
+        inet_proto_csum_replace2(check, skb, *port, new_port, 0);
+        *port = new_port;
+        skb->rxhash = 0;
+}
+
+static int set_udp_port(struct sk_buff *skb,
+                        const struct ovs_key_udp *udp_port_key)
+{
+        struct udphdr *uh;
+        int err;
+
+        err = make_writable(skb, skb_transport_offset(skb) +
+                                 sizeof(struct udphdr));
+        if (unlikely(err))
+                return err;
+
+        uh = udp_hdr(skb);
+        if (udp_port_key->udp_src != uh->source)
+                set_tp_port(skb, &uh->source, udp_port_key->udp_src, &uh->check);
+
+        if (udp_port_key->udp_dst != uh->dest)
+                set_tp_port(skb, &uh->dest, udp_port_key->udp_dst, &uh->check);
+
+        return 0;
+}
+
+static int set_tcp_port(struct sk_buff *skb,
+                        const struct ovs_key_tcp *tcp_port_key)
+{
+        struct tcphdr *th;
+        int err;
+
+        err = make_writable(skb, skb_transport_offset(skb) +
+                                 sizeof(struct tcphdr));
+        if (unlikely(err))
+                return err;
+
+        th = tcp_hdr(skb);
+        if (tcp_port_key->tcp_src != th->source)
+                set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
+
+        if (tcp_port_key->tcp_dst != th->dest)
+                set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
+
+        return 0;
+}
+
+static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
+{
+        struct vport *vport;
+
+        if (unlikely(!skb))
+                return -ENOMEM;
+
+        vport = rcu_dereference(dp->ports[out_port]);
+        if (unlikely(!vport)) {
+                kfree_skb(skb);
+                return -ENODEV;
+        }
+
+        ovs_vport_send(vport, skb);
+        return 0;
+}
+
+static int output_userspace(struct datapath *dp, struct sk_buff *skb,
+                            const struct nlattr *attr)
+{
+        struct dp_upcall_info upcall;
+        const struct nlattr *a;
+        int rem;
+
+        upcall.cmd = OVS_PACKET_CMD_ACTION;
+        upcall.key = &OVS_CB(skb)->flow->key;
+        upcall.userdata = NULL;
+        upcall.pid = 0;
+
+        for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
+                 a = nla_next(a, &rem)) {
+                switch (nla_type(a)) {
+                case OVS_USERSPACE_ATTR_USERDATA:
+                        upcall.userdata = a;
+                        break;
+
+                case OVS_USERSPACE_ATTR_PID:
+                        upcall.pid = nla_get_u32(a);
+                        break;
+                }
+        }
+
+        return ovs_dp_upcall(dp, skb, &upcall);
+}
+
+static int sample(struct datapath *dp, struct sk_buff *skb,
+                  const struct nlattr *attr)
+{
+        const struct nlattr *acts_list = NULL;
+        const struct nlattr *a;
+        int rem;
+
+        for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
+                 a = nla_next(a, &rem)) {
+                switch (nla_type(a)) {
+                case OVS_SAMPLE_ATTR_PROBABILITY:
+                        if (net_random() >= nla_get_u32(a))
+                                return 0;
+                        break;
+
+                case OVS_SAMPLE_ATTR_ACTIONS:
+                        acts_list = a;
+                        break;
+                }
+        }
+
+        return do_execute_actions(dp, skb, nla_data(acts_list),
+                                                 nla_len(acts_list), true);
+}
+
+static int execute_set_action(struct sk_buff *skb,
+                                 const struct nlattr *nested_attr)
+{
+        int err = 0;
+
+        switch (nla_type(nested_attr)) {
+        case OVS_KEY_ATTR_PRIORITY:
+                skb->priority = nla_get_u32(nested_attr);
+                break;
+
+        case OVS_KEY_ATTR_ETHERNET:
+                err = set_eth_addr(skb, nla_data(nested_attr));
+                break;
+
+        case OVS_KEY_ATTR_IPV4:
+                err = set_ipv4(skb, nla_data(nested_attr));
+                break;
+
+        case OVS_KEY_ATTR_TCP:
+                err = set_tcp_port(skb, nla_data(nested_attr));
+                break;
+
+        case OVS_KEY_ATTR_UDP:
+                err = set_udp_port(skb, nla_data(nested_attr));
+                break;
+        }
+
+        return err;
+}
+
+/* Execute a list of actions against 'skb'. */
+static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
+                        const struct nlattr *attr, int len, bool keep_skb)
+{
+        /* Every output action needs a separate clone of 'skb', but the common
+         * case is just a single output action, so that doing a clone and
+         * then freeing the original skbuff is wasteful.  So the following code
+         * is slightly obscure just to avoid that. */
+        int prev_port = -1;
+        const struct nlattr *a;
+        int rem;
+
+        for (a = attr, rem = len; rem > 0;
+             a = nla_next(a, &rem)) {
+                int err = 0;
+
+                if (prev_port != -1) {
+                        do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
+                        prev_port = -1;
+                }
+
+                switch (nla_type(a)) {
+                case OVS_ACTION_ATTR_OUTPUT:
+                        prev_port = nla_get_u32(a);
+                        break;
+
+                case OVS_ACTION_ATTR_USERSPACE:
+                        output_userspace(dp, skb, a);
+                        break;
+
+                case OVS_ACTION_ATTR_PUSH_VLAN:
+                        err = push_vlan(skb, nla_data(a));
+                        if (unlikely(err)) /* skb already freed. */
+                                return err;
+                        break;
+
+                case OVS_ACTION_ATTR_POP_VLAN:
+                        err = pop_vlan(skb);
+                        break;
+
+                case OVS_ACTION_ATTR_SET:
+                        err = execute_set_action(skb, nla_data(a));
+                        break;
+
+                case OVS_ACTION_ATTR_SAMPLE:
+                        err = sample(dp, skb, a);
+                        break;
+                }
+
+                if (unlikely(err)) {
+                        kfree_skb(skb);
+                        return err;
+                }
+        }
+
+        if (prev_port != -1) {
+                if (keep_skb)
+                        skb = skb_clone(skb, GFP_ATOMIC);
+
+                do_output(dp, skb, prev_port);
+        } else if (!keep_skb)
+                consume_skb(skb);
+
+        return 0;
+}
+
+/* Execute a list of actions against 'skb'. */
+int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
+{
+        struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
+
+        return do_execute_actions(dp, skb, acts->actions,
+                                         acts->actions_len, false);
+}