+++ /dev/null
-/*
- * Copyright (c) 2007-2011 Nicira, Inc.
- *
- * 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/in.h>
-#include <linux/ip.h>
-#include <linux/tcp.h>
-#include <linux/udp.h>
-
-#include "checksum.h"
-#include "datapath.h"
-
-#ifdef NEED_CSUM_NORMALIZE
-
-#if defined(CONFIG_XEN) && defined(HAVE_PROTO_DATA_VALID)
-/* This code is based on skb_checksum_setup() from Xen's net/dev/core.c. We
- * can't call this function directly because it isn't exported in all
- * versions. */
-static int vswitch_skb_checksum_setup(struct sk_buff *skb)
-{
- struct iphdr *iph;
- unsigned char *th;
- int err = -EPROTO;
- __u16 csum_start, csum_offset;
-
- if (!skb->proto_csum_blank)
- return 0;
-
- if (skb->protocol != htons(ETH_P_IP))
- goto out;
-
- if (!pskb_may_pull(skb, skb_network_header(skb) + sizeof(struct iphdr) - skb->data))
- goto out;
-
- iph = ip_hdr(skb);
- th = skb_network_header(skb) + 4 * iph->ihl;
-
- csum_start = th - skb->head;
- switch (iph->protocol) {
- case IPPROTO_TCP:
- csum_offset = offsetof(struct tcphdr, check);
- break;
- case IPPROTO_UDP:
- csum_offset = offsetof(struct udphdr, check);
- break;
- default:
- if (net_ratelimit())
- pr_err("Attempting to checksum a non-TCP/UDP packet, "
- "dropping a protocol %d packet",
- iph->protocol);
- goto out;
- }
-
- if (!pskb_may_pull(skb, th + csum_offset + 2 - skb->data))
- goto out;
-
- skb->proto_csum_blank = 0;
- set_ip_summed(skb, OVS_CSUM_PARTIAL);
- set_skb_csum_pointers(skb, csum_start, csum_offset);
-
- err = 0;
-
-out:
- return err;
-}
-#else
-static int vswitch_skb_checksum_setup(struct sk_buff *skb)
-{
- return 0;
-}
-#endif /* not Xen old style checksums */
-
-/*
- * compute_ip_summed - map external checksum state onto OVS representation
- *
- * @skb: Packet to manipulate.
- * @xmit: Whether we were on transmit path of network stack. For example,
- * this is true for the internal dev vport because it receives skbs
- * that passed through dev_queue_xmit() but false for the netdev vport
- * because its packets come from netif_receive_skb().
- *
- * Older kernels (and various versions of Xen) were not explicit enough about
- * checksum offload parameters and rely on a combination of context and
- * non standard fields. This deals with all those variations so that we
- * can internally manipulate checksum offloads without worrying about kernel
- * version.
- *
- * Types of checksums that we can receive (these all refer to L4 checksums):
- * 1. CHECKSUM_NONE: Device that did not compute checksum, contains full
- * (though not verified) checksum in packet but not in skb->csum. Packets
- * from the bridge local port will also have this type.
- * 2. CHECKSUM_COMPLETE (CHECKSUM_HW): Good device that computes checksums,
- * also the GRE module. This is the same as CHECKSUM_NONE, except it has
- * a valid skb->csum. Importantly, both contain a full checksum (not
- * verified) in the packet itself. The only difference is that if the
- * packet gets to L4 processing on this machine (not in DomU) we won't
- * have to recompute the checksum to verify. Most hardware devices do not
- * produce packets with this type, even if they support receive checksum
- * offloading (they produce type #5).
- * 3. CHECKSUM_PARTIAL (CHECKSUM_HW): Packet without full checksum and needs to
- * be computed if it is sent off box. Unfortunately on earlier kernels,
- * this case is impossible to distinguish from #2, despite having opposite
- * meanings. Xen adds an extra field on earlier kernels (see #4) in order
- * to distinguish the different states.
- * 4. CHECKSUM_UNNECESSARY (with proto_csum_blank true): This packet was
- * generated locally by a Xen DomU and has a partial checksum. If it is
- * handled on this machine (Dom0 or DomU), then the checksum will not be
- * computed. If it goes off box, the checksum in the packet needs to be
- * completed. Calling skb_checksum_setup converts this to CHECKSUM_HW
- * (CHECKSUM_PARTIAL) so that the checksum can be completed. In later
- * kernels, this combination is replaced with CHECKSUM_PARTIAL.
- * 5. CHECKSUM_UNNECESSARY (with proto_csum_blank false): Packet with a correct
- * full checksum or using a protocol without a checksum. skb->csum is
- * undefined. This is common from devices with receive checksum
- * offloading. This is somewhat similar to CHECKSUM_NONE, except that
- * nobody will try to verify the checksum with CHECKSUM_UNNECESSARY.
- *
- * Note that on earlier kernels, CHECKSUM_COMPLETE and CHECKSUM_PARTIAL are
- * both defined as CHECKSUM_HW. Normally the meaning of CHECKSUM_HW is clear
- * based on whether it is on the transmit or receive path. After the datapath
- * it will be intepreted as CHECKSUM_PARTIAL. If the packet already has a
- * checksum, we will panic. Since we can receive packets with checksums, we
- * assume that all CHECKSUM_HW packets have checksums and map them to
- * CHECKSUM_NONE, which has a similar meaning (the it is only different if the
- * packet is processed by the local IP stack, in which case it will need to
- * be reverified). If we receive a packet with CHECKSUM_HW that really means
- * CHECKSUM_PARTIAL, it will be sent with the wrong checksum. However, there
- * shouldn't be any devices that do this with bridging.
- */
-int compute_ip_summed(struct sk_buff *skb, bool xmit)
-{
- /* For our convenience these defines change repeatedly between kernel
- * versions, so we can't just copy them over...
- */
- switch (skb->ip_summed) {
- case CHECKSUM_NONE:
- set_ip_summed(skb, OVS_CSUM_NONE);
- break;
- case CHECKSUM_UNNECESSARY:
- set_ip_summed(skb, OVS_CSUM_UNNECESSARY);
- break;
-#ifdef CHECKSUM_HW
- /* In theory this could be either CHECKSUM_PARTIAL or CHECKSUM_COMPLETE.
- * However, on the receive side we should only get CHECKSUM_PARTIAL
- * packets from Xen, which uses some special fields to represent this
- * (see vswitch_skb_checksum_setup()). Since we can only make one type
- * work, pick the one that actually happens in practice.
- *
- * On the transmit side (basically after skb_checksum_setup()
- * has been run or on internal dev transmit), packets with
- * CHECKSUM_COMPLETE aren't generated, so assume CHECKSUM_PARTIAL.
- */
- case CHECKSUM_HW:
- if (!xmit)
- set_ip_summed(skb, OVS_CSUM_COMPLETE);
- else
- set_ip_summed(skb, OVS_CSUM_PARTIAL);
- break;
-#else
- case CHECKSUM_COMPLETE:
- set_ip_summed(skb, OVS_CSUM_COMPLETE);
- break;
- case CHECKSUM_PARTIAL:
- set_ip_summed(skb, OVS_CSUM_PARTIAL);
- break;
-#endif
- }
-
- OVS_CB(skb)->csum_start = skb_headroom(skb) + skb_transport_offset(skb);
-
- return vswitch_skb_checksum_setup(skb);
-}
-
-/*
- * forward_ip_summed - map internal checksum state back onto native
- * kernel fields.
- *
- * @skb: Packet to manipulate.
- * @xmit: Whether we are about send on the transmit path the network stack.
- * This follows the same logic as the @xmit field in compute_ip_summed().
- * Generally, a given vport will have opposite values for @xmit passed to
- * these two functions.
- *
- * When a packet is about to egress from OVS take our internal fields (including
- * any modifications we have made) and recreate the correct representation for
- * this kernel. This may do things like change the transport header offset.
- */
-void forward_ip_summed(struct sk_buff *skb, bool xmit)
-{
- switch (get_ip_summed(skb)) {
- case OVS_CSUM_NONE:
- skb->ip_summed = CHECKSUM_NONE;
- break;
- case OVS_CSUM_UNNECESSARY:
- skb->ip_summed = CHECKSUM_UNNECESSARY;
-#if defined(CONFIG_XEN) && defined(HAVE_PROTO_DATA_VALID)
- skb->proto_data_valid = 1;
-#endif
- break;
-#ifdef CHECKSUM_HW
- case OVS_CSUM_COMPLETE:
- if (!xmit)
- skb->ip_summed = CHECKSUM_HW;
- else
- skb->ip_summed = CHECKSUM_NONE;
- break;
- case OVS_CSUM_PARTIAL:
- if (!xmit) {
- skb->ip_summed = CHECKSUM_UNNECESSARY;
-#if defined(CONFIG_XEN) && defined(HAVE_PROTO_DATA_VALID)
- skb->proto_csum_blank = 1;
-#endif
- } else {
- skb->ip_summed = CHECKSUM_HW;
- }
- break;
-#else
- case OVS_CSUM_COMPLETE:
- skb->ip_summed = CHECKSUM_COMPLETE;
- break;
- case OVS_CSUM_PARTIAL:
- skb->ip_summed = CHECKSUM_PARTIAL;
- break;
-#endif
- }
-
- if (get_ip_summed(skb) == OVS_CSUM_PARTIAL)
- skb_set_transport_header(skb, OVS_CB(skb)->csum_start -
- skb_headroom(skb));
-}
-
-u8 get_ip_summed(struct sk_buff *skb)
-{
- return OVS_CB(skb)->ip_summed;
-}
-
-void set_ip_summed(struct sk_buff *skb, u8 ip_summed)
-{
- OVS_CB(skb)->ip_summed = ip_summed;
-}
-
-void get_skb_csum_pointers(const struct sk_buff *skb, u16 *csum_start,
- u16 *csum_offset)
-{
- *csum_start = OVS_CB(skb)->csum_start;
- *csum_offset = skb->csum;
-}
-
-void set_skb_csum_pointers(struct sk_buff *skb, u16 csum_start,
- u16 csum_offset)
-{
- OVS_CB(skb)->csum_start = csum_start;
- skb->csum = csum_offset;
-}
-#endif /* NEED_CSUM_NORMALIZE */
git://git.onelab.eu / sliver-openvswitch.git / blobdiff