This prevents using an older datapath from breaking forwarding.
CC: Romain Lenglet <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>
---
v1->v2: Check for variable-length data support in the correct place
(see Romain's comments in http://patchwork.openvswitch.org/patch/1627/).
ofproto/ofproto-dpif-xlate.c | 18 ++++++++-
ofproto/ofproto-dpif-xlate.h | 2 +-
ofproto/ofproto-dpif.c | 92 +++++++++++++++++++++++++++++++++++++++++-
3 files changed, 109 insertions(+), 3 deletions(-)
diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
index 848c778..558598c 100644
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -87,6 +87,11 @@ struct xbridge {
enum ofp_config_flags frag; /* Fragmentation handling. */
bool has_in_band; /* Bridge has in band control? */
bool forward_bpdu; /* Bridge forwards STP BPDUs? */
+
+ /* True if the datapath supports variable-length
+ * OVS_USERSPACE_ATTR_USERDATA in OVS_ACTION_ATTR_USERSPACE actions.
+ * False if the datapath supports only 8-byte (or shorter) userdata. */
+ bool variable_length_userdata;
};
struct xbundle {
@@ -249,7 +254,8 @@ xlate_ofproto_set(struct ofproto_dpif *ofproto, const char
*name,
const struct dpif_sflow *sflow,
const struct dpif_ipfix *ipfix,
const struct netflow *netflow, enum ofp_config_flags frag,
- bool forward_bpdu, bool has_in_band)
+ bool forward_bpdu, bool has_in_band,
+ bool variable_length_userdata)
{
struct xbridge *xbridge = xbridge_lookup(ofproto);
@@ -301,6 +307,7 @@ xlate_ofproto_set(struct ofproto_dpif *ofproto, const char
*name,
xbridge->frag = frag;
xbridge->miss_rule = miss_rule;
xbridge->no_packet_in_rule = no_packet_in_rule;
+ xbridge->variable_length_userdata = variable_length_userdata;
}
void
@@ -2521,6 +2528,15 @@ xlate_sample_action(struct xlate_ctx *ctx,
* the same percentage. */
uint32_t probability = (os->probability << 16) | os->probability;
+ if (!ctx->xbridge->variable_length_userdata) {
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
+
+ VLOG_ERR_RL(&rl, "ignoring NXAST_SAMPLE action because datapath "
+ "lacks support (needs Linux 3.10+ or kernel module from "
+ "OVS 1.11+)");
+ return;
+ }
+
ctx->xout->slow |= commit_odp_actions(&ctx->xin->flow, &ctx->base_flow,
&ctx->xout->odp_actions,
&ctx->xout->wc,
diff --git a/ofproto/ofproto-dpif-xlate.h b/ofproto/ofproto-dpif-xlate.h
index 68076ca..982f1a4 100644
--- a/ofproto/ofproto-dpif-xlate.h
+++ b/ofproto/ofproto-dpif-xlate.h
@@ -129,7 +129,7 @@ void xlate_ofproto_set(struct ofproto_dpif *, const char
*name,
const struct mbridge *, const struct dpif_sflow *,
const struct dpif_ipfix *, const struct netflow *,
enum ofp_config_flags, bool forward_bpdu,
- bool has_in_band)
+ bool has_in_band, bool variable_length_userdata)
OVS_REQ_WRLOCK(xlate_rwlock);
void xlate_remove_ofproto(struct ofproto_dpif *) OVS_REQ_WRLOCK(xlate_rwlock);
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 52759b5..e48cc00 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -42,6 +42,7 @@
#include "netdev-vport.h"
#include "netdev.h"
#include "netlink.h"
+#include "netlink-socket.h"
#include "nx-match.h"
#include "odp-util.h"
#include "odp-execute.h"
@@ -251,6 +252,11 @@ struct dpif_backer {
enum revalidate_reason need_revalidate; /* Revalidate all flows. */
bool recv_set_enable; /* Enables or disables receiving packets. */
+
+ /* True if the datapath supports variable-length
+ * OVS_USERSPACE_ATTR_USERDATA in OVS_ACTION_ATTR_USERSPACE actions.
+ * False if the datapath supports only 8-byte (or shorter) userdata. */
+ bool variable_length_userdata;
};
/* All existing ofproto_backer instances, indexed by ofproto->up.type. */
@@ -552,7 +558,8 @@ type_run(const char *type)
ofproto->sflow, ofproto->ipfix,
ofproto->netflow, ofproto->up.frag_handling,
ofproto->up.forward_bpdu,
- connmgr_has_in_band(ofproto->up.connmgr));
+ connmgr_has_in_band(ofproto->up.connmgr),
+ ofproto->backer->variable_length_userdata);
HMAP_FOR_EACH (bundle, hmap_node, &ofproto->bundles) {
xlate_bundle_set(ofproto, bundle, bundle->name,
@@ -774,6 +781,8 @@ struct odp_garbage {
odp_port_t odp_port;
};
+static bool check_variable_length_userdata(struct dpif_backer *backer);
+
static int
open_dpif_backer(const char *type, struct dpif_backer **backerp)
{
@@ -872,6 +881,7 @@ open_dpif_backer(const char *type, struct dpif_backer
**backerp)
close_dpif_backer(backer);
return error;
}
+ backer->variable_length_userdata = check_variable_length_userdata(backer);
if (backer->recv_set_enable) {
udpif_set_threads(backer->udpif, n_handlers, n_revalidators);
@@ -880,6 +890,86 @@ open_dpif_backer(const char *type, struct dpif_backer
**backerp)
return error;
}
+/* Tests whether 'backer''s datapath supports variable-length
+ * OVS_USERSPACE_ATTR_USERDATA in OVS_ACTION_ATTR_USERSPACE actions. We need
+ * to disable some features on older datapaths that don't support this
+ * feature.
+ *
+ * Returns false if 'backer' definitely does not support variable-length
+ * userdata, true if it seems to support them or if at least the error we get
+ * is ambiguous. */
+static bool
+check_variable_length_userdata(struct dpif_backer *backer)
+{
+ struct eth_header *eth;
+ struct ofpbuf actions;
+ struct ofpbuf key;
+ struct ofpbuf packet;
+ size_t start;
+ int error;
+
+ /* Compose a userspace action that will cause an ERANGE error on older
+ * datapaths that don't support variable-length userdata.
+ *
+ * We really test for using userdata longer than 8 bytes, but older
+ * datapaths accepted these, silently truncating the userdata to 8 bytes.
+ * The same older datapaths rejected userdata shorter than 8 bytes, so we
+ * test for that instead as a proxy for longer userdata support. */
+ ofpbuf_init(&actions, 64);
+ start = nl_msg_start_nested(&actions, OVS_ACTION_ATTR_USERSPACE);
+ nl_msg_put_u32(&actions, OVS_USERSPACE_ATTR_PID,
+ dpif_port_get_pid(backer->dpif, ODPP_NONE));
+ nl_msg_put_unspec_zero(&actions, OVS_USERSPACE_ATTR_USERDATA, 4);
+ nl_msg_end_nested(&actions, start);
+
+ /* Compose an ODP flow key. The key is arbitrary but it must match the
+ * packet that we compose later. */
+ ofpbuf_init(&key, 64);
+ nl_msg_put_u32(&key, OVS_KEY_ATTR_IN_PORT, 0);
+ nl_msg_put_unspec_zero(&key, OVS_KEY_ATTR_ETHERNET,
+ sizeof(struct ovs_key_ethernet));
+ nl_msg_put_be16(&key, OVS_KEY_ATTR_ETHERTYPE, htons(0x1234));
+
+ /* Compose a packet that matches the key. */
+ ofpbuf_init(&packet, ETH_HEADER_LEN);
+ eth = ofpbuf_put_zeros(&packet, ETH_HEADER_LEN);
+ eth->eth_type = htons(0x1234);
+
+ /* Execute the actions. On older datapaths this fails with -ERANGE, on
+ * newer datapaths it succeeds. */
+ error = dpif_execute(backer->dpif, key.data, key.size,
+ actions.data, actions.size, &packet, false);
+
+ ofpbuf_uninit(&packet);
+ ofpbuf_uninit(&key);
+ ofpbuf_uninit(&actions);
+
+ switch (error) {
+ case 0:
+ /* Variable-length userdata is supported.
+ *
+ * Purge received packets to avoid processing the nonsense packet we
+ * sent to userspace, then report success. */
+ dpif_recv_purge(backer->dpif);
+ return true;
+
+ case ERANGE:
+ /* Variable-length userdata is not supported. */
+ VLOG_WARN("%s: datapath does not support variable-length userdata "
+ "feature (needs Linux 3.10+ or kernel module from OVS "
+ "1..11+). The NXAST_SAMPLE action will be ignored.",
+ dpif_name(backer->dpif));
+ return false;
+
+ default:
+ /* Something odd happened. We're not sure whether variable-length
+ * userdata is supported. Default to "yes". */
+ VLOG_WARN("%s: variable-length userdata feature probe failed (%s)",
+ dpif_name(backer->dpif), ovs_strerror(error));
+ return true;
+ }
+}
+
static int
construct(struct ofproto *ofproto_)
{
--
1.7.10.4
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