datapath: Support CHECKSUM_PARTIAL on older kernels.

[sliver-openvswitch.git] / datapath / actions.c

diff --git a/datapath/actions.c b/datapath/actions.c
index 1526328..b059cc0 100644 (file)
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -1,6 +1,6 @@
 /*
  * Distributed under the terms of the GNU GPL version 2.
- * Copyright (c) 2007, 2008, 2009 Nicira Networks.
+ * Copyright (c) 2007, 2008, 2009, 2010 Nicira Networks.
  *
  * Significant portions of this file may be copied from parts of the Linux
  * kernel, by Linus Torvalds and others.
@@ -37,7 +37,7 @@ make_writable(struct sk_buff *skb, unsigned min_headroom, gfp_t gfp)
                        nskb->ip_summed = skb->ip_summed;
                        nskb->csum = skb->csum;
 #endif
-#if defined(CONFIG_XEN) && LINUX_VERSION_CODE == KERNEL_VERSION(2,6,18)
+#if defined(CONFIG_XEN) && defined(HAVE_PROTO_DATA_VALID)
                        /* These fields are copied in skb_clone but not in
                         * skb_copy or related functions.  We need to manually
                         * copy them over here. */
@@ -112,7 +112,7 @@ modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                 * when we send the packet out on the wire, and it will fail at
                 * that point because skb_checksum_setup() will not look inside
                 * an 802.1Q header. */
-               skb_checksum_setup(skb);
+               vswitch_skb_checksum_setup(skb);
 
                /* GSO is not implemented for packets with an 802.1Q header, so
                 * we have to do segmentation before we add that header.
@@ -213,10 +213,43 @@ static void update_csum(__sum16 *sum, struct sk_buff *skb,
                        __be32 from, __be32 to, int pseudohdr)
 {
        __be32 diff[] = { ~from, to };
-       if (skb->ip_summed != CHECKSUM_PARTIAL) {
+
+/* On older kernels, CHECKSUM_PARTIAL and CHECKSUM_COMPLETE are both defined
+ * as CHECKSUM_HW.  However, we can make some inferences so that we can update
+ * the checksums appropriately. */
+       enum {
+               CSUM_PARTIAL,   /* Partial checksum, skb->csum undefined. */
+               CSUM_PACKET,    /* In-packet checksum, skb->csum undefined. */
+               CSUM_COMPLETE,  /* In-packet checksum, skb->csum valid. */
+       } csum_type;
+
+       csum_type = CSUM_PACKET;
+#ifndef CHECKSUM_HW
+       /* Newer kernel, just map between kernel types and ours. */
+       if (skb->ip_summed == CHECKSUM_PARTIAL)
+               csum_type = CSUM_PARTIAL;
+       else if (skb->ip_summed == CHECKSUM_COMPLETE)
+               csum_type = CSUM_COMPLETE;
+#else
+       /* In theory this could be either CHECKSUM_PARTIAL or CHECKSUM_COMPLETE.
+        * However, we should only get CHECKSUM_PARTIAL packets from Xen, which
+        * uses some special fields to represent this (see below).  Since we
+        * can only make one type work, pick the one that actually happens in
+        * practice. */
+       if (skb->ip_summed == CHECKSUM_HW)
+               csum_type = CSUM_COMPLETE;
+#endif
+#if defined(CONFIG_XEN) && defined(HAVE_PROTO_DATA_VALID)
+       /* Xen has a special way of representing CHECKSUM_PARTIAL on older
+        * kernels. */
+       if (skb->proto_csum_blank)
+               csum_type = CSUM_PARTIAL;
+#endif
+
+       if (csum_type != CSUM_PARTIAL) {
                *sum = csum_fold(csum_partial((char *)diff, sizeof(diff),
                                ~csum_unfold(*sum)));
-               if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
+               if (csum_type == CSUM_COMPLETE && pseudohdr)
                        skb->csum = ~csum_partial((char *)diff, sizeof(diff),
                                                ~skb->csum);
        } else if (pseudohdr)
@@ -275,8 +308,8 @@ set_tp_port(struct sk_buff *skb, struct odp_flow_key *key,
                u16 *f = a->type == ODPAT_SET_TP_SRC ? &th->source : &th->dest;
                u16 old = *f;
                u16 new = a->tp_port;
-               update_csum((u16*)((u8*)skb->data + check_ofs),
-                           skb, old, new, 1);
+               update_csum((u16*)(skb_transport_header(skb) + check_ofs), 
+                               skb, old, new, 0);
                *f = new;
        }
        return skb;
@@ -302,6 +335,7 @@ int dp_xmit_skb(struct sk_buff *skb)
                return -E2BIG;
        }
 
+       forward_ip_summed(skb);
        dev_queue_xmit(skb);
 
        return len;
@@ -323,7 +357,7 @@ do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
        dev = skb->dev = p->dev;
        if (is_dp_dev(dev))
                dp_dev_recv(dev, skb);
-        else
+       else
                dp_xmit_skb(skb);
        return;
 
@@ -377,7 +411,7 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
         * then freeing the original skbuff is wasteful.  So the following code
         * is slightly obscure just to avoid that. */
        int prev_port = -1;
-       int err = 0;
+       int err;
        for (; n_actions > 0; a++, n_actions--) {
                WARN_ON_ONCE(skb_shared(skb));
                if (prev_port != -1) {
@@ -436,5 +470,5 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                do_output(dp, skb, prev_port);
        else
                kfree_skb(skb);
-       return err;
+       return 0;
 }