From: Ethan Jackson <ethan@nicira.com>
Date: Wed, 20 Jul 2011 22:07:46 +0000 (-0700)
Subject: bundle: New action "bundle_load".
X-Git-Tag: v1.2.0~54
X-Git-Url: http://git.onelab.eu/?a=commitdiff_plain;ds=sidebyside;h=a368bb53d9769ae42042e122775672ac9546e3f9;p=sliver-openvswitch.git

bundle: New action "bundle_load".

The bundle_load action behaves the same as the bundle action,
except instead of outputting, it writes its result to a register.
---

diff --git a/include/openflow/nicira-ext.h b/include/openflow/nicira-ext.h
index 09f4ee392..b97cd4fcb 100644
--- a/include/openflow/nicira-ext.h
+++ b/include/openflow/nicira-ext.h
@@ -278,7 +278,8 @@ enum nx_action_subtype {
     NXAST_SET_TUNNEL64,         /* struct nx_action_set_tunnel64 */
     NXAST_MULTIPATH,            /* struct nx_action_multipath */
     NXAST_AUTOPATH,             /* struct nx_action_autopath */
-    NXAST_BUNDLE                /* struct nx_action_bundle */
+    NXAST_BUNDLE,               /* struct nx_action_bundle */
+    NXAST_BUNDLE_LOAD           /* struct nx_action_bundle */
 };
 
 /* Header for Nicira-defined actions. */
@@ -664,10 +665,11 @@ struct nx_action_autopath {
 };
 OFP_ASSERT(sizeof(struct nx_action_autopath) == 24);
 
-/* Action structure for NXAST_BUNDLE.
+/* Action structure for NXAST_BUNDLE and NXAST_BUNDLE_LOAD.
  *
- * NXAST_BUNDLE chooses a slave from a supplied list of options, and outputs to
- * its selection.
+ * The bundle actions choose a slave from a supplied list of options.
+ * NXAST_BUNDLE outputs to its selection.  NXAST_BUNDLE_LOAD writes its
+ * selection to a register.
  *
  * The list of possible slaves follows the nx_action_bundle structure. The size
  * of each slave is governed by its type as indicated by the 'slave_type'
@@ -693,7 +695,14 @@ OFP_ASSERT(sizeof(struct nx_action_autopath) == 24);
  *
  * The 'zero' parameter at the end of the action structure is reserved for
  * future use.  Switches are required to reject actions which have nonzero
- * bytes in the 'zero' field. */
+ * bytes in the 'zero' field.
+ *
+ * NXAST_BUNDLE actions should have 'ofs_nbits' and 'dst' zeroed.  Switches
+ * should reject actions which have nonzero bytes in either of these fields.
+ *
+ * NXAST_BUNDLE_LOAD stores the OpenFlow port number of the selected slave in
+ * dst[ofs:ofs+n_bits].  The format and semantics of 'dst' and 'ofs_nbits' are
+ * similar to those for the NXAST_REG_LOAD action. */
 struct nx_action_bundle {
     ovs_be16 type;              /* OFPAT_VENDOR. */
     ovs_be16 len;               /* Length including slaves. */
@@ -710,7 +719,10 @@ struct nx_action_bundle {
     ovs_be32 slave_type;        /* NXM_OF_IN_PORT. */
     ovs_be16 n_slaves;          /* Number of slaves. */
 
-    uint8_t zero[10];           /* Reserved. Must be zero. */
+    ovs_be16 ofs_nbits;         /* (ofs << 6) | (n_bits - 1). */
+    ovs_be32 dst;               /* Destination. */
+
+    uint8_t zero[4];            /* Reserved. Must be zero. */
 };
 OFP_ASSERT(sizeof(struct nx_action_bundle) == 32);
 
diff --git a/lib/bundle.c b/lib/bundle.c
index 593bd87d9..227d3597c 100644
--- a/lib/bundle.c
+++ b/lib/bundle.c
@@ -88,12 +88,22 @@ bundle_execute(const struct nx_action_bundle *nab, const struct flow *flow,
     }
 }
 
+void
+bundle_execute_load(const struct nx_action_bundle *nab, struct flow *flow,
+                    bool (*slave_enabled)(uint16_t ofp_port, void *aux),
+                    void *aux)
+{
+    nxm_reg_load(nab->dst, nab->ofs_nbits,
+                 bundle_execute(nab, flow, slave_enabled, aux), flow);
+}
+
 /* Checks that 'nab' specifies a bundle action which is supported by this
  * bundle module.  Uses the 'max_ports' parameter to validate each port using
  * ofputil_check_output_port().  Returns 0 if 'nab' is supported, otherwise an
  * OpenFlow error code (as returned by ofp_mkerr()). */
 int
-bundle_check(const struct nx_action_bundle *nab, int max_ports)
+bundle_check(const struct nx_action_bundle *nab, int max_ports,
+             const struct flow *flow)
 {
     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
     uint16_t n_slaves, fields, algorithm, subtype;
@@ -129,6 +139,15 @@ bundle_check(const struct nx_action_bundle *nab, int max_ports)
         }
     }
 
+    if (subtype == NXAST_BUNDLE && (nab->ofs_nbits || nab->dst)) {
+        VLOG_WARN_RL(&rl, "bundle action has nonzero reserved fields");
+        error = ofp_mkerr(OFPET_BAD_ACTION, OFPBAC_BAD_ARGUMENT);
+    }
+
+    if (subtype == NXAST_BUNDLE_LOAD) {
+        error = nxm_dst_check(nab->dst, nab->ofs_nbits, 16, flow) || error;
+    }
+
     if (slaves_size < n_slaves * sizeof(ovs_be16)) {
         VLOG_WARN_RL(&rl, "Nicira action %"PRIu16" only has %zu bytes "
                      "allocated for slaves.  %zu bytes are required for "
@@ -158,24 +177,16 @@ bundle_check(const struct nx_action_bundle *nab, int max_ports)
     return error;
 }
 
-/* Converts a bundle action string contained in 's' to an nx_action_bundle and
- * stores it in 'b'.  Sets 'b''s l2 pointer to NULL. */
-void
-bundle_parse(struct ofpbuf *b, const char *s)
+/* Helper for bundle_parse and bundle_parse_load. */
+static void
+bundle_parse__(struct ofpbuf *b, const char *s, char **save_ptr,
+               const char *fields, const char *basis, const char *algorithm,
+               const char *slave_type, const char *dst,
+               const char *slave_delim)
 {
-    char *fields, *basis, *algorithm, *slave_type, *slave_delim;
     struct nx_action_bundle *nab;
-    char *tokstr, *save_ptr;
     uint16_t n_slaves;
 
-    save_ptr = NULL;
-    tokstr = xstrdup(s);
-    fields = strtok_r(tokstr, ", ", &save_ptr);
-    basis = strtok_r(NULL, ", ", &save_ptr);
-    algorithm = strtok_r(NULL, ", ", &save_ptr);
-    slave_type = strtok_r(NULL, ", ", &save_ptr);
-    slave_delim = strtok_r(NULL, ": ", &save_ptr);
-
     if (!slave_delim) {
         ovs_fatal(0, "%s: not enough arguments to bundle action", s);
     }
@@ -192,7 +203,7 @@ bundle_parse(struct ofpbuf *b, const char *s)
         ovs_be16 slave_be;
         char *slave;
 
-        slave = strtok_r(NULL, ", ", &save_ptr);
+        slave = strtok_r(NULL, ", ", save_ptr);
         if (!slave || n_slaves >= BUNDLE_MAX_SLAVES) {
             break;
         }
@@ -212,7 +223,7 @@ bundle_parse(struct ofpbuf *b, const char *s)
     nab->type = htons(OFPAT_VENDOR);
     nab->len = htons(b->size - ((char *) b->l2 - (char *) b->data));
     nab->vendor = htonl(NX_VENDOR_ID);
-    nab->subtype = htons(NXAST_BUNDLE);
+    nab->subtype = htons(dst ? NXAST_BUNDLE_LOAD: NXAST_BUNDLE);
     nab->n_slaves = htons(n_slaves);
     nab->basis = htons(atoi(basis));
 
@@ -238,7 +249,60 @@ bundle_parse(struct ofpbuf *b, const char *s)
         ovs_fatal(0, "%s: unknown slave_type `%s'", s, slave_type);
     }
 
+    if (dst) {
+        uint32_t reg;
+        int ofs, n_bits;
+
+        nxm_parse_field_bits(dst, &reg, &ofs, &n_bits);
+
+        nab->dst = htonl(reg);
+        nab->ofs_nbits = nxm_encode_ofs_nbits(ofs, n_bits);
+    }
+
     b->l2 = NULL;
+}
+
+/* Converts a bundle action string contained in 's' to an nx_action_bundle and
+ * stores it in 'b'.  Sets 'b''s l2 pointer to NULL. */
+void
+bundle_parse(struct ofpbuf *b, const char *s)
+{
+    char *fields, *basis, *algorithm, *slave_type, *slave_delim;
+    char *tokstr, *save_ptr;
+
+    save_ptr = NULL;
+    tokstr = xstrdup(s);
+    fields = strtok_r(tokstr, ", ", &save_ptr);
+    basis = strtok_r(NULL, ", ", &save_ptr);
+    algorithm = strtok_r(NULL, ", ", &save_ptr);
+    slave_type = strtok_r(NULL, ", ", &save_ptr);
+    slave_delim = strtok_r(NULL, ": ", &save_ptr);
+
+    bundle_parse__(b, s, &save_ptr, fields, basis, algorithm, slave_type, NULL,
+                   slave_delim);
+    free(tokstr);
+}
+
+/* Converts a bundle_load action string contained in 's' to an nx_action_bundle
+ * and stores it in 'b'.  Sets 'b''s l2 pointer to NULL. */
+void
+bundle_parse_load(struct ofpbuf *b, const char *s)
+{
+    char *fields, *basis, *algorithm, *slave_type, *dst, *slave_delim;
+    char *tokstr, *save_ptr;
+
+    save_ptr = NULL;
+    tokstr = xstrdup(s);
+    fields = strtok_r(tokstr, ", ", &save_ptr);
+    basis = strtok_r(NULL, ", ", &save_ptr);
+    algorithm = strtok_r(NULL, ", ", &save_ptr);
+    slave_type = strtok_r(NULL, ", ", &save_ptr);
+    dst = strtok_r(NULL, ", ", &save_ptr);
+    slave_delim = strtok_r(NULL, ": ", &save_ptr);
+
+    bundle_parse__(b, s, &save_ptr, fields, basis, algorithm, slave_type, dst,
+                   slave_delim);
+
     free(tokstr);
 }
 
@@ -246,7 +310,7 @@ bundle_parse(struct ofpbuf *b, const char *s)
 void
 bundle_format(const struct nx_action_bundle *nab, struct ds *s)
 {
-    const char *fields, *algorithm, *slave_type;
+    const char *action, *fields, *algorithm, *slave_type;
     size_t i;
 
     fields = flow_hash_fields_to_str(ntohs(nab->fields));
@@ -270,9 +334,28 @@ bundle_format(const struct nx_action_bundle *nab, struct ds *s)
         slave_type = "<unknown>";
     }
 
-    ds_put_format(s, "bundle(%s,%"PRIu16",%s,%s,slaves:", fields,
+    switch (ntohs(nab->subtype)) {
+    case NXAST_BUNDLE:
+        action = "bundle";
+        break;
+    case NXAST_BUNDLE_LOAD:
+        action = "bundle_load";
+        break;
+    default:
+        NOT_REACHED();
+    }
+
+    ds_put_format(s, "%s(%s,%"PRIu16",%s,%s,", action, fields,
                   ntohs(nab->basis), algorithm, slave_type);
 
+    if (nab->subtype == htons(NXAST_BUNDLE_LOAD)) {
+        nxm_format_field_bits(s, ntohl(nab->dst),
+                              nxm_decode_ofs(nab->ofs_nbits),
+                              nxm_decode_n_bits(nab->ofs_nbits));
+        ds_put_cstr(s, ",");
+    }
+
+    ds_put_cstr(s, "slaves:");
     for (i = 0; i < ntohs(nab->n_slaves); i++) {
         if (i) {
             ds_put_cstr(s, ",");
diff --git a/lib/bundle.h b/lib/bundle.h
index a202ade49..12497f788 100644
--- a/lib/bundle.h
+++ b/lib/bundle.h
@@ -35,8 +35,13 @@ struct ofpbuf;
 uint16_t bundle_execute(const struct nx_action_bundle *, const struct flow *,
                         bool (*slave_enabled)(uint16_t ofp_port, void *aux),
                         void *aux);
-int bundle_check(const struct nx_action_bundle *, int max_ports);
+void bundle_execute_load(const struct nx_action_bundle *, struct flow *,
+                         bool (*slave_enabled)(uint16_t ofp_port, void *aux),
+                         void *aux);
+int bundle_check(const struct nx_action_bundle *, int max_ports,
+                 const struct flow *);
 void bundle_parse(struct ofpbuf *, const char *);
+void bundle_parse_load(struct ofpbuf *b, const char *);
 void bundle_format(const struct nx_action_bundle *, struct ds *);
 
 /* Returns the 'i'th slave in 'nab'. */
diff --git a/lib/ofp-parse.c b/lib/ofp-parse.c
index 25056e7f3..58b0da1ea 100644
--- a/lib/ofp-parse.c
+++ b/lib/ofp-parse.c
@@ -507,6 +507,8 @@ str_to_action(char *str, struct ofpbuf *b)
             autopath_parse(naa, arg);
         } else if (!strcasecmp(act, "bundle")) {
             bundle_parse(b, arg);
+        } else if (!strcasecmp(act, "bundle_load")) {
+            bundle_parse_load(b, arg);
         } else if (!strcasecmp(act, "output")) {
             put_output_action(b, str_to_u32(arg));
         } else if (!strcasecmp(act, "enqueue")) {
diff --git a/lib/ofp-print.c b/lib/ofp-print.c
index aa3ff542e..cb361a633 100644
--- a/lib/ofp-print.c
+++ b/lib/ofp-print.c
@@ -344,6 +344,7 @@ ofp_print_action(struct ds *s, const union ofp_action *a,
         break;
 
     case OFPUTIL_NXAST_BUNDLE:
+    case OFPUTIL_NXAST_BUNDLE_LOAD:
         bundle_format((const struct nx_action_bundle *) a, s);
         break;
 
diff --git a/lib/ofp-util.c b/lib/ofp-util.c
index 2e62b9188..df3377ae9 100644
--- a/lib/ofp-util.c
+++ b/lib/ofp-util.c
@@ -2039,8 +2039,9 @@ validate_actions(const union ofp_action *actions, size_t n_actions,
             break;
 
         case OFPUTIL_NXAST_BUNDLE:
+        case OFPUTIL_NXAST_BUNDLE_LOAD:
             error = bundle_check((const struct nx_action_bundle *) a,
-                                 max_ports);
+                                 max_ports, flow);
             break;
 
         case OFPUTIL_OFPAT_STRIP_VLAN:
@@ -2116,6 +2117,7 @@ static const struct ofputil_nxast_action nxast_actions[] = {
     { OFPUTIL_NXAST_MULTIPATH,    32, 32 },
     { OFPUTIL_NXAST_AUTOPATH,     24, 24 },
     { OFPUTIL_NXAST_BUNDLE,       32, UINT_MAX },
+    { OFPUTIL_NXAST_BUNDLE_LOAD,  32, UINT_MAX },
 };
 
 static int
diff --git a/lib/ofp-util.h b/lib/ofp-util.h
index 7938aa0c2..7ee3e69f7 100644
--- a/lib/ofp-util.h
+++ b/lib/ofp-util.h
@@ -302,7 +302,8 @@ enum ofputil_action_code {
     OFPUTIL_NXAST_SET_TUNNEL64,
     OFPUTIL_NXAST_MULTIPATH,
     OFPUTIL_NXAST_AUTOPATH,
-    OFPUTIL_NXAST_BUNDLE
+    OFPUTIL_NXAST_BUNDLE,
+    OFPUTIL_NXAST_BUNDLE_LOAD,
 };
 
 int ofputil_decode_action(const union ofp_action *);
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index c88569cf3..61685b726 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -3228,6 +3228,13 @@ do_xlate_actions(const union ofp_action *in, size_t n_in,
                                                       slave_enabled_cb,
                                                       ctx->ofproto), 0);
             break;
+
+        case OFPUTIL_NXAST_BUNDLE_LOAD:
+            ctx->ofproto->has_bundle_action = true;
+            nab = (const struct nx_action_bundle *) ia;
+            bundle_execute_load(nab, &ctx->flow, slave_enabled_cb,
+                                ctx->ofproto);
+            break;
         }
     }
 }
diff --git a/tests/bundle.at b/tests/bundle.at
index 8a8cb4f2f..8a3c29193 100644
--- a/tests/bundle.at
+++ b/tests/bundle.at
@@ -8,7 +8,7 @@ AT_BANNER([bundle link selection])
 # if the test does fail.
 
 AT_SETUP([hrw bundle link selection])
-AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,slaves:1,2,3,4,5,6']],
+AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,NXM_NX_REG0[],slaves:1,2,3,4,5']],
   [0], [ignore])
 # 100000: disruption=1.00 (perfect=1.00) 1.00 0.00 0.00 0.00 0.00 0.00
 # 110000: disruption=0.50 (perfect=0.50) 0.50 0.50 0.00 0.00 0.00 0.00
@@ -78,7 +78,7 @@ AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,slaves:1,2,3,4,5,6']],
 AT_CLEANUP
 
 AT_SETUP([active_backup bundle link selection])
-AT_CHECK([[test-bundle 'symmetric_l4,60,active_backup,ofport,slaves:1,2,3,4,5,6']],
+AT_CHECK([[test-bundle 'symmetric_l4,60,active_backup,ofport,NXM_NX_REG0[],slaves:1,2,3,4,5,6']],
   [0],
 [100000: disruption=1.00 (perfect=1.00) 1.00 0.00 0.00 0.00 0.00 0.00
 110000: disruption=0.00 (perfect=0.00) 1.00 0.00 0.00 0.00 0.00 0.00
@@ -149,7 +149,7 @@ AT_CHECK([[test-bundle 'symmetric_l4,60,active_backup,ofport,slaves:1,2,3,4,5,6'
 AT_CLEANUP
 
 AT_SETUP([hrw bundle single link selection])
-AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,slaves:1']],
+AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,NXM_NX_REG0[],slaves:1']],
   [0], [ignore])
 # 1: disruption=1.00 (perfect=1.00) 1.00
 # 0: disruption=1.00 (perfect=1.00) 0.00
@@ -157,7 +157,7 @@ AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,slaves:1']],
 AT_CLEANUP
 
 AT_SETUP([hrw bundle no link selection])
-AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,slaves:']],
+AT_CHECK([[test-bundle 'symmetric_l4,60,hrw,ofport,NXM_NX_REG0[],slaves:']],
   [0], [ignore])
 AT_CLEANUP
 #: disruption=0.00 (perfect=0.00)
diff --git a/tests/ovs-ofctl.at b/tests/ovs-ofctl.at
index 63292dbb4..1b4cfd90e 100644
--- a/tests/ovs-ofctl.at
+++ b/tests/ovs-ofctl.at
@@ -19,6 +19,10 @@ actions=bundle(eth_src,50,active_backup,ofport,slaves:1)
 actions=bundle(symmetric_l4,60,hrw,ofport,slaves:2,3)
 actions=bundle(symmetric_l4,60,hrw,ofport,slaves:)
 actions=output:1,bundle(eth_src,0,hrw,ofport,slaves:1),output:2
+actions=bundle_load(eth_src,50,active_backup,ofport,NXM_NX_REG0[],slaves:1)
+actions=bundle_load(symmetric_l4,60,hrw,ofport,NXM_NX_REG0[0..15],slaves:2,3)
+actions=bundle_load(symmetric_l4,60,hrw,ofport,NXM_NX_REG0[0..30],slaves:)
+actions=output:1,bundle_load(eth_src,0,hrw,ofport,NXM_NX_REG0[16..31],slaves:1),output:2
 ]])
 AT_CHECK([ovs-ofctl parse-flows flows.txt
 ], [0], [stdout])
@@ -41,6 +45,10 @@ NXT_FLOW_MOD: ADD table:255 actions=bundle(eth_src,50,active_backup,ofport,slave
 NXT_FLOW_MOD: ADD table:255 actions=bundle(symmetric_l4,60,hrw,ofport,slaves:2,3)
 NXT_FLOW_MOD: ADD table:255 actions=bundle(symmetric_l4,60,hrw,ofport,slaves:)
 NXT_FLOW_MOD: ADD table:255 actions=output:1,bundle(eth_src,0,hrw,ofport,slaves:1),output:2
+NXT_FLOW_MOD: ADD table:255 actions=bundle_load(eth_src,50,active_backup,ofport,NXM_NX_REG0[],slaves:1)
+NXT_FLOW_MOD: ADD table:255 actions=bundle_load(symmetric_l4,60,hrw,ofport,NXM_NX_REG0[0..15],slaves:2,3)
+NXT_FLOW_MOD: ADD table:255 actions=bundle_load(symmetric_l4,60,hrw,ofport,NXM_NX_REG0[0..30],slaves:)
+NXT_FLOW_MOD: ADD table:255 actions=output:1,bundle_load(eth_src,0,hrw,ofport,NXM_NX_REG0[16..31],slaves:1),output:2
 ]])
 AT_CLEANUP
 
diff --git a/tests/test-bundle.c b/tests/test-bundle.c
index fb15faf98..16e264d2b 100644
--- a/tests/test-bundle.c
+++ b/tests/test-bundle.c
@@ -71,7 +71,7 @@ parse_bundle_actions(char *actions)
     struct ofpbuf b;
 
     ofpbuf_init(&b, 0);
-    bundle_parse(&b, actions);
+    bundle_parse_load(&b, actions);
     nab = ofpbuf_steal_data(&b);
     ofpbuf_uninit(&b);
 
@@ -136,7 +136,7 @@ main(int argc, char *argv[])
         flows[i].regs[0] = OFPP_NONE;
     }
 
-    if (bundle_check(nab, 1024)) {
+    if (bundle_check(nab, 1024, flows)) {
         ovs_fatal(0, "Bundle action fails to check.");
     }
 
@@ -185,10 +185,15 @@ main(int argc, char *argv[])
         changed = 0;
         for (j = 0; j < N_FLOWS; j++) {
             struct flow *flow = &flows[j];
-            uint16_t old_slave_id;
+            uint16_t old_slave_id, ofp_port;
 
             old_slave_id = flow->regs[0];
-            flow->regs[0] = bundle_execute(nab, flow, slave_enabled_cb, &sg);
+            ofp_port = bundle_execute(nab, flow, slave_enabled_cb, &sg);
+            bundle_execute_load(nab, flow, slave_enabled_cb, &sg);
+            if (flow->regs[0] != ofp_port) {
+                ovs_fatal(0, "bundle_execute_load() and bundle_execute() "
+                          "disagree");
+            }
 
             if (flow->regs[0] != OFPP_NONE) {
                 slave_lookup(&sg, flow->regs[0])->flow_count++;
diff --git a/utilities/ovs-ofctl.8.in b/utilities/ovs-ofctl.8.in
index b45f01c6d..bb52be22e 100644
--- a/utilities/ovs-ofctl.8.in
+++ b/utilities/ovs-ofctl.8.in
@@ -743,6 +743,19 @@ hash with basis 0, to select between OpenFlow ports 4 and 8 using the Highest
 Random Weight algorithm.
 .IP
 Refer to \fBnicira\-ext.h\fR for more details.
+.
+.IP "\fBbundle_load(\fIfields\fB, \fIbasis\fB, \fIalgorithm\fB, \fIslave_type\fB, \fIdst\fB[\fIstart\fB..\fIend\fB], slaves:[\fIs1\fB, \fIs2\fB, ...])\fR"
+Has the same behavior as the \fBbundle\fR action, with one exception.  Instead
+of outputting to the selected slave, it writes its selection to
+\fIdst\fB[\fIstart\fB..\fIend\fB]\fR, which must be an NXM field as described
+above.
+.IP
+Example: \fBbundle_load(eth_src,0,hrw,ofport,NXM_NX_REG0[],slaves:4,8)\fR uses
+an Ethernet source hash with basis 0, to select between OpenFlow ports 4 and 8
+using the Highest Random Weight algorithm, and writes the selection to
+\fBNXM_NX_REG0[]\fR.
+.IP
+Refer to \fBnicira\-ext.h\fR for more details.
 .RE
 .
 .IP