ovn-trace: Implement DHCP option support.

The put_dhcp_opts(v6) logical action didn't really work because ovn-trace
didn't handle DHCP options.  This fixes the problem.

This also makes the put_dhcp_opts(v6) logical provide useful tracing output
showing what's happening and the assumptions.

Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Numan Siddique <nusiddiq@redhat.com>

1 files changed, 59 insertions, 4 deletions

diff --git a/ovn/utilities/ovn-trace.c b/ovn/utilities/ovn-trace.c
index 04aa5326d..71798f8b8 100644
--- a/ovn/utilities/ovn-trace.c
+++ b/ovn/utilities/ovn-trace.c
@@ -33,6 +33,7 @@
 #include "ovn/lex.h"
 #include "ovn/lib/logical-fields.h"
 #include "ovn/lib/ovn-sb-idl.h"
+#include "ovn/lib/ovn-dhcp.h"
 #include "ovn/lib/ovn-util.h"
 #include "ovsdb-idl.h"
 #include "poll-loop.h"
@@ -338,6 +339,10 @@ static struct shash symtab;
 /* Address sets. */
 static struct shash address_sets;
 
+/* DHCP options. */
+static struct hmap dhcp_opts;   /* Contains "struct dhcp_opts_map"s. */
+static struct hmap dhcpv6_opts; /* Contains "struct dhcp_opts_map"s. */
+
 static struct ovntrace_datapath *
 ovntrace_datapath_find_by_sb_uuid(const struct uuid *sb_uuid)
 {
@@ -608,7 +613,8 @@ read_flows(void)
 
         struct ovnact_parse_params pp = {
             .symtab = &symtab,
-            .dhcp_opts = NULL /* XXX */,
+            .dhcp_opts = &dhcp_opts,
+            .dhcpv6_opts = &dhcpv6_opts,
             .n_tables = 16,
             .cur_ltable = sblf->table_id,
         };
@@ -666,6 +672,23 @@ read_flows(void)
 }
 
 static void
+read_dhcp_opts(void)
+{
+    hmap_init(&dhcp_opts);
+    const struct sbrec_dhcp_options *sdo;
+    SBREC_DHCP_OPTIONS_FOR_EACH (sdo, ovnsb_idl) {
+        dhcp_opt_add(&dhcp_opts, sdo->name, sdo->code, sdo->type);
+    }
+
+
+    hmap_init(&dhcpv6_opts);
+    const struct sbrec_dhcpv6_options *sdo6;
+    SBREC_DHCPV6_OPTIONS_FOR_EACH(sdo6, ovnsb_idl) {
+       dhcp_opt_add(&dhcpv6_opts, sdo6->name, sdo6->code, sdo6->type);
+    }
+}
+
+static void
 read_mac_bindings(void)
 {
     const struct sbrec_mac_binding *sbmb;
@@ -713,6 +736,7 @@ read_db(void)
     read_ports();
     read_mcgroups();
     read_address_sets();
+    read_dhcp_opts();
     read_flows();
     read_mac_bindings();
 }
@@ -1209,8 +1233,37 @@ execute_get_mac_bind(const struct ovnact_get_mac_bind *bind,
 
 static void
 execute_put_dhcp_opts(const struct ovnact_put_dhcp_opts *pdo,
-                      struct flow *uflow)
+                      const char *name, struct flow *uflow,
+                      struct ovs_list *super)
 {
+    ovntrace_node_append(
+        super, OVNTRACE_NODE_ERROR,
+        "/* We assume that this packet is DHCPDISCOVER or DHCPREQUEST. */");
+
+    /* Format the put_dhcp_opts action. */
+    struct ds s = DS_EMPTY_INITIALIZER;
+    for (const struct ovnact_dhcp_option *o = pdo->options;
+         o < &pdo->options[pdo->n_options]; o++) {
+        if (o != pdo->options) {
+            ds_put_cstr(&s, ", ");
+        }
+        ds_put_format(&s, "%s = ", o->option->name);
+        expr_constant_set_format(&o->value, &s);
+    }
+    ovntrace_node_append(super, OVNTRACE_NODE_MODIFY, "%s(%s)",
+                         name, ds_cstr(&s));
+    ds_destroy(&s);
+
+    struct mf_subfield dst = expr_resolve_field(&pdo->dst);
+    if (!mf_is_register(dst.field->id)) {
+        /* Format assignment. */
+        struct ds s = DS_EMPTY_INITIALIZER;
+        expr_field_format(&pdo->dst, &s);
+        ovntrace_node_append(super, OVNTRACE_NODE_MODIFY,
+                             "%s = 1", ds_cstr(&s));
+        ds_destroy(&s);
+    }
+
     struct mf_subfield sf = expr_resolve_field(&pdo->dst);
     union mf_subvalue sv = { .u8_val = 1 };
     mf_write_subfield_flow(&sf, &sv, uflow);
@@ -1304,11 +1357,13 @@ trace_actions(const struct ovnact *ovnacts, size_t ovnacts_len,
             break;
 
         case OVNACT_PUT_DHCPV4_OPTS:
-            execute_put_dhcp_opts(ovnact_get_PUT_DHCPV4_OPTS(a), uflow);
+            execute_put_dhcp_opts(ovnact_get_PUT_DHCPV4_OPTS(a),
+                                  "put_dhcp_opts", uflow, super);
             break;
 
         case OVNACT_PUT_DHCPV6_OPTS:
-            execute_put_dhcp_opts(ovnact_get_PUT_DHCPV6_OPTS(a), uflow);
+            execute_put_dhcp_opts(ovnact_get_PUT_DHCPV6_OPTS(a),
+                                  "put_dhcpv6_opts", uflow, super);
             break;
 
         case OVNACT_SET_QUEUE: