xen-netback: add control protocol implementation
My recent patch to include/xen/interface/io/netif.h defines a new shared
ring (in addition to the rx and tx rings) for passing control messages
from a VM frontend driver to a backend driver.
A previous patch added the necessary boilerplate for mapping the control
ring from the frontend, should it be created. This patch adds
implementations for each of the defined protocol messages.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
new file mode 100644
index 0000000..392e392
--- /dev/null
+++ b/drivers/net/xen-netback/hash.c
@@ -0,0 +1,384 @@
+/*
+ * Copyright (c) 2016 Citrix Systems Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Softare Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define XEN_NETIF_DEFINE_TOEPLITZ
+
+#include "common.h"
+#include <linux/vmalloc.h>
+#include <linux/rculist.h>
+
+static void xenvif_del_hash(struct rcu_head *rcu)
+{
+ struct xenvif_hash_cache_entry *entry;
+
+ entry = container_of(rcu, struct xenvif_hash_cache_entry, rcu);
+
+ kfree(entry);
+}
+
+static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,
+ unsigned int len, u32 val)
+{
+ struct xenvif_hash_cache_entry *new, *entry, *oldest;
+ unsigned long flags;
+ bool found;
+
+ new = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (!new)
+ return;
+
+ memcpy(new->tag, tag, len);
+ new->len = len;
+ new->val = val;
+
+ spin_lock_irqsave(&vif->hash.cache.lock, flags);
+
+ found = false;
+ oldest = NULL;
+ list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
+ /* Make sure we don't add duplicate entries */
+ if (entry->len == len &&
+ memcmp(entry->tag, tag, len) == 0)
+ found = true;
+ if (!oldest || entry->seq < oldest->seq)
+ oldest = entry;
+ }
+
+ if (!found) {
+ new->seq = atomic_inc_return(&vif->hash.cache.seq);
+ list_add_rcu(&new->link, &vif->hash.cache.list);
+
+ if (++vif->hash.cache.count > xenvif_hash_cache_size) {
+ list_del_rcu(&oldest->link);
+ vif->hash.cache.count--;
+ call_rcu(&oldest->rcu, xenvif_del_hash);
+ }
+ }
+
+ spin_unlock_irqrestore(&vif->hash.cache.lock, flags);
+
+ if (found)
+ kfree(new);
+}
+
+static u32 xenvif_new_hash(struct xenvif *vif, const u8 *data,
+ unsigned int len)
+{
+ u32 val;
+
+ val = xen_netif_toeplitz_hash(vif->hash.key,
+ sizeof(vif->hash.key),
+ data, len);
+
+ if (xenvif_hash_cache_size != 0)
+ xenvif_add_hash(vif, data, len, val);
+
+ return val;
+}
+
+static void xenvif_flush_hash(struct xenvif *vif)
+{
+ struct xenvif_hash_cache_entry *entry;
+ unsigned long flags;
+
+ if (xenvif_hash_cache_size == 0)
+ return;
+
+ spin_lock_irqsave(&vif->hash.cache.lock, flags);
+
+ list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
+ list_del_rcu(&entry->link);
+ vif->hash.cache.count--;
+ call_rcu(&entry->rcu, xenvif_del_hash);
+ }
+
+ spin_unlock_irqrestore(&vif->hash.cache.lock, flags);
+}
+
+static u32 xenvif_find_hash(struct xenvif *vif, const u8 *data,
+ unsigned int len)
+{
+ struct xenvif_hash_cache_entry *entry;
+ u32 val;
+ bool found;
+
+ if (len >= XEN_NETBK_HASH_TAG_SIZE)
+ return 0;
+
+ if (xenvif_hash_cache_size == 0)
+ return xenvif_new_hash(vif, data, len);
+
+ rcu_read_lock();
+
+ found = false;
+
+ list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
+ if (entry->len == len &&
+ memcmp(entry->tag, data, len) == 0) {
+ val = entry->val;
+ entry->seq = atomic_inc_return(&vif->hash.cache.seq);
+ found = true;
+ break;
+ }
+ }
+
+ rcu_read_unlock();
+
+ if (!found)
+ val = xenvif_new_hash(vif, data, len);
+
+ return val;
+}
+
+void xenvif_set_skb_hash(struct xenvif *vif, struct sk_buff *skb)
+{
+ struct flow_keys flow;
+ u32 hash = 0;
+ enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
+ u32 flags = vif->hash.flags;
+ bool has_tcp_hdr;
+
+ /* Quick rejection test: If the network protocol doesn't
+ * correspond to any enabled hash type then there's no point
+ * in parsing the packet header.
+ */
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV4))
+ break;
+
+ goto done;
+
+ case htons(ETH_P_IPV6):
+ if (flags & (XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV6))
+ break;
+
+ goto done;
+
+ default:
+ goto done;
+ }
+
+ memset(&flow, 0, sizeof(flow));
+ if (!skb_flow_dissect_flow_keys(skb, &flow, 0))
+ goto done;
+
+ has_tcp_hdr = (flow.basic.ip_proto == IPPROTO_TCP) &&
+ !(flow.control.flags & FLOW_DIS_IS_FRAGMENT);
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ if (has_tcp_hdr &&
+ (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP)) {
+ u8 data[12];
+
+ memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
+ memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
+ memcpy(&data[8], &flow.ports.src, 2);
+ memcpy(&data[10], &flow.ports.dst, 2);
+
+ hash = xenvif_find_hash(vif, data, sizeof(data));
+ type = PKT_HASH_TYPE_L4;
+ } else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV4) {
+ u8 data[8];
+
+ memcpy(&data[0], &flow.addrs.v4addrs.src, 4);
+ memcpy(&data[4], &flow.addrs.v4addrs.dst, 4);
+
+ hash = xenvif_find_hash(vif, data, sizeof(data));
+ type = PKT_HASH_TYPE_L3;
+ }
+
+ break;
+
+ case htons(ETH_P_IPV6):
+ if (has_tcp_hdr &&
+ (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP)) {
+ u8 data[36];
+
+ memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
+ memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
+ memcpy(&data[32], &flow.ports.src, 2);
+ memcpy(&data[34], &flow.ports.dst, 2);
+
+ hash = xenvif_find_hash(vif, data, sizeof(data));
+ type = PKT_HASH_TYPE_L4;
+ } else if (flags & XEN_NETIF_CTRL_HASH_TYPE_IPV6) {
+ u8 data[32];
+
+ memcpy(&data[0], &flow.addrs.v6addrs.src, 16);
+ memcpy(&data[16], &flow.addrs.v6addrs.dst, 16);
+
+ hash = xenvif_find_hash(vif, data, sizeof(data));
+ type = PKT_HASH_TYPE_L3;
+ }
+
+ break;
+ }
+
+done:
+ if (type == PKT_HASH_TYPE_NONE)
+ skb_clear_hash(skb);
+ else
+ __skb_set_sw_hash(skb, hash, type == PKT_HASH_TYPE_L4);
+}
+
+u32 xenvif_set_hash_alg(struct xenvif *vif, u32 alg)
+{
+ switch (alg) {
+ case XEN_NETIF_CTRL_HASH_ALGORITHM_NONE:
+ case XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ:
+ break;
+
+ default:
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+ }
+
+ vif->hash.alg = alg;
+
+ return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+u32 xenvif_get_hash_flags(struct xenvif *vif, u32 *flags)
+{
+ if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
+ return XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
+
+ *flags = XEN_NETIF_CTRL_HASH_TYPE_IPV4 |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV6 |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
+
+ return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+u32 xenvif_set_hash_flags(struct xenvif *vif, u32 flags)
+{
+ if (flags & ~(XEN_NETIF_CTRL_HASH_TYPE_IPV4 |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV6 |
+ XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP))
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+ if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+ vif->hash.flags = flags;
+
+ return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+u32 xenvif_set_hash_key(struct xenvif *vif, u32 gref, u32 len)
+{
+ u8 *key = vif->hash.key;
+ struct gnttab_copy copy_op = {
+ .source.u.ref = gref,
+ .source.domid = vif->domid,
+ .dest.u.gmfn = virt_to_gfn(key),
+ .dest.domid = DOMID_SELF,
+ .dest.offset = xen_offset_in_page(key),
+ .len = len,
+ .flags = GNTCOPY_source_gref
+ };
+
+ if (len > XEN_NETBK_MAX_HASH_KEY_SIZE)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+ if (len != 0) {
+ gnttab_batch_copy(©_op, 1);
+
+ if (copy_op.status != GNTST_okay)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+ }
+
+ /* Clear any remaining key octets */
+ if (len < XEN_NETBK_MAX_HASH_KEY_SIZE)
+ memset(key + len, 0, XEN_NETBK_MAX_HASH_KEY_SIZE - len);
+
+ xenvif_flush_hash(vif);
+
+ return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+u32 xenvif_set_hash_mapping_size(struct xenvif *vif, u32 size)
+{
+ if (size > XEN_NETBK_MAX_HASH_MAPPING_SIZE)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+ vif->hash.size = size;
+ memset(vif->hash.mapping, 0, sizeof(u32) * size);
+
+ return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+u32 xenvif_set_hash_mapping(struct xenvif *vif, u32 gref, u32 len,
+ u32 off)
+{
+ u32 *mapping = &vif->hash.mapping[off];
+ struct gnttab_copy copy_op = {
+ .source.u.ref = gref,
+ .source.domid = vif->domid,
+ .dest.u.gmfn = virt_to_gfn(mapping),
+ .dest.domid = DOMID_SELF,
+ .dest.offset = xen_offset_in_page(mapping),
+ .len = len * sizeof(u32),
+ .flags = GNTCOPY_source_gref
+ };
+
+ if ((off + len > vif->hash.size) || copy_op.len > XEN_PAGE_SIZE)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+ while (len-- != 0)
+ if (mapping[off++] >= vif->num_queues)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+
+ if (len != 0) {
+ gnttab_batch_copy(©_op, 1);
+
+ if (copy_op.status != GNTST_okay)
+ return XEN_NETIF_CTRL_STATUS_INVALID_PARAMETER;
+ }
+
+ return XEN_NETIF_CTRL_STATUS_SUCCESS;
+}
+
+void xenvif_init_hash(struct xenvif *vif)
+{
+ if (xenvif_hash_cache_size == 0)
+ return;
+
+ spin_lock_init(&vif->hash.cache.lock);
+ INIT_LIST_HEAD(&vif->hash.cache.list);
+}
+
+void xenvif_deinit_hash(struct xenvif *vif)
+{
+ xenvif_flush_hash(vif);
+}