add 'iif' key to routing-policy entry

It's now possible to specify the incoming interface for a routing
policy entry.

Example:

  network:
    version: 2
    ethernets:
      if0: {}
      eth0:
        dhcp4: true
        routing-policy:
          - table: 101
            iif: if0

Signed-off-by: Emanuele Altomare <emanuele@common-net.org>

doc/netplan-yaml.md

@@ -865,6 +865,10 @@ network:
 
     > Match on traffic going to the specified destination.
 
+  - **`iif`** (scalar)
+
+    > Set an incoming interface to match traffic for this policy rule.
+
   - **`table`** (scalar)
 
     > The table number to match for the route. In some scenarios, it may be

src/netplan.c

@@ -641,6 +641,7 @@ write_routes(yaml_event_t* event, yaml_emitter_t* emitter, const NetplanNetDefin
             YAML_UINT_DEFAULT(def, event, emitter, "mark", r->fwmark, NETPLAN_IP_RULE_FW_MARK_UNSPEC);
             YAML_STRING(def, event, emitter, "from", r->from);
             YAML_STRING(def, event, emitter, "to", r->to);
+            YAML_STRING(def, event, emitter, "iif", r->iif);
             YAML_MAPPING_CLOSE(event, emitter);
         }
         YAML_SEQUENCE_CLOSE(event, emitter);

src/networkd.c

@@ -749,6 +749,9 @@ write_ip_rule(NetplanIPRule* r, GString* s)
         g_string_append_printf(s, "From=%s\n", r->from);
     if (r->to)
         g_string_append_printf(s, "To=%s\n", r->to);
+    if (r->iif)
+        g_string_append_printf(s, "IncomingInterface=%s\n", r->iif);
+
 
     if (r->table != NETPLAN_ROUTE_TABLE_UNSPEC)
         g_string_append_printf(s, "Table=%d\n", r->table);

src/nm.c

@@ -297,6 +297,8 @@ write_ip_rules_nm(const NetplanNetDefinition* def, GKeyFile *kf, gint family, GE
                 g_string_append_printf(tmp_val, " from %s", cur_rule->from);
             if (cur_rule->to)
                 g_string_append_printf(tmp_val, " to %s", cur_rule->to);
+            if (cur_rule->iif)
+                g_string_append_printf(tmp_val, " iif %s", cur_rule->iif);
             if (cur_rule->tos != NETPLAN_IP_RULE_TOS_UNSPEC)
                 g_string_append_printf(tmp_val, " tos %u", cur_rule->tos);
             if (cur_rule->fwmark != NETPLAN_IP_RULE_FW_MARK_UNSPEC)

src/parse.c

@@ -386,6 +386,21 @@ handle_generic_str(NetplanParser* npp, yaml_node_t* node, void* entryptr, const
     return TRUE;
 }
 
+/**
+ * Handler for setting a string ID field from a scalar node, inside a given struct
+ * @entryptr: pointer to the beginning of the to-be-modified data structure
+ * @data: offset into entryptr struct where the const char* field to write is
+ *        located
+ */
+STATIC gboolean
+handle_generic_id(NetplanParser* npp, yaml_node_t* node, void* entryptr, const void* data, GError** error)
+{
+    if (!assert_valid_id(npp, node, error))
+        return FALSE;
+
+    return handle_generic_str(npp, node, entryptr, data, error);
+}
+
 STATIC gboolean
 handle_special_macaddress_option(NetplanParser* npp, yaml_node_t* node, void* entryptr, const void* data, GError** error)
 {
@@ -2048,6 +2063,12 @@ handle_ip_rule_ip(NetplanParser* npp, yaml_node_t* node, const void* data, GErro
     return TRUE;
 }
 
+STATIC gboolean
+handle_ip_rule_iif(NetplanParser* npp, yaml_node_t* node, const void* data, GError** error)
+{
+    return handle_generic_id(npp, node, npp->current.ip_rule, (void *) data, error);
+}
+
 STATIC gboolean
 handle_ip_rule_guint(NetplanParser* npp, yaml_node_t* node, const void* data, GError** error)
 {
@@ -2295,6 +2316,7 @@ static const mapping_entry_handler ip_rules_handlers[] = {
     {"table", YAML_SCALAR_NODE, {.generic=handle_ip_rule_guint}, ip_rule_offset(table)},
     {"to", YAML_SCALAR_NODE, {.generic=handle_ip_rule_ip}, ip_rule_offset(to)},
     {"type-of-service", YAML_SCALAR_NODE, {.generic=handle_ip_rule_tos}, ip_rule_offset(tos)},
+    {"iif", YAML_SCALAR_NODE, {.generic=handle_ip_rule_iif}, ip_rule_offset(iif)},
     {NULL}
 };
 
@@ -2309,11 +2331,12 @@ handle_ip_rules(NetplanParser* npp, yaml_node_t* node, __unused const void* _, G
         reset_ip_rule(ip_rule);
 
         npp->current.ip_rule = ip_rule;
+
         ret = process_mapping(npp, entry, NULL, ip_rules_handlers, NULL, error);
         npp->current.ip_rule = NULL;
 
-        if (ret && !ip_rule->from && !ip_rule->to)
-            ret = yaml_error(npp, node, error, "IP routing policy must include either a 'from' or 'to' IP");
+        if (ret && !ip_rule->from && !ip_rule->to && !ip_rule->iif)
+            ret = yaml_error(npp, node, error, "IP routing policy must include at least one of the following fields: 'from', 'to', 'iif'");
 
         if (!ret) {
             ip_rule_clear(&ip_rule);

src/types-internal.h

@@ -168,6 +168,9 @@ typedef struct {
     guint fwmark;
     /* type-of-service: between 0 and 255 */
     guint tos;
+
+    /* incoming interface */
+    char* iif;
 } NetplanIPRule;
 
 struct netplan_vxlan {

src/types.c

@@ -87,6 +87,7 @@ free_ip_rules(void* ptr)
     NetplanIPRule* rule = ptr;
     g_free(rule->to);
     g_free(rule->from);
+    g_free(rule->iif);
     g_free(rule);
 }
 

src/util.c

@@ -1210,7 +1210,8 @@ is_route_rule_present(const NetplanNetDefinition* netdef, const NetplanIPRule* r
                 entry->table == rule->table &&
                 entry->priority == rule->priority &&
                 entry->fwmark == rule->fwmark &&
-                entry->tos == rule->tos
+                entry->tos == rule->tos &&
+                g_strcmp0(entry->iif, rule->iif) == 0
            )
             return TRUE;
     }

tests/generator/test_errors.py

@@ -916,6 +916,18 @@ def test_device_ip_rule_invalid_address(self):
         - 192.168.14.2/24
         - 2001:FFfe::1/64''', expect_fail=True)
 
+    def test_device_ip_rule_invalid_iif(self):
+        self.generate('''network:
+  version: 2
+  ethernets:
+    engreen:
+      routing-policy:
+        - from: 10.10.10.0/24
+          iif: not valid iface name
+      addresses:
+        - 192.168.14.2/24
+        - 2001:FFfe::1/64''', expect_fail=True)
+
     def test_invalid_dhcp_identifier(self):
         self.generate('''network:
   version: 2

tests/generator/test_routing.py

@@ -654,6 +654,31 @@ def test_ip_rule_tos(self):
 [RoutingPolicyRule]
 To=10.10.10.0/24
 TypeOfService=250
+'''})
+
+    def test_ip_rule_iif(self):
+        self.generate('''network:
+  version: 2
+  ethernets:
+    engreen:
+      addresses: ["192.168.14.2/24"]
+      routing-policy:
+        - to: 10.10.10.0/24
+          table: 100
+          iif: if0
+          ''')
+
+        self.assert_networkd({'engreen.network': '''[Match]
+Name=engreen
+
+[Network]
+LinkLocalAddressing=ipv6
+Address=192.168.14.2/24
+
+[RoutingPolicyRule]
+To=10.10.10.0/24
+IncomingInterface=if0
+Table=100
 '''})
 
     def test_use_routes(self):
@@ -1185,6 +1210,37 @@ def test_ip_rule_tos(self):
 address1=192.168.14.2/24
 routing-rule1=priority 99 to 10.10.10.0/24 tos 250
 
+[ipv6]
+method=ignore
+'''})
+
+    def test_ip_rule_iif(self):
+        self.generate('''network:
+  version: 2
+  renderer: NetworkManager
+  ethernets:
+    engreen:
+      addresses: ["192.168.14.2/24"]
+      routing-policy:
+        - to: 10.10.10.0/24
+          table: 100
+          priority: 99
+          iif: if0
+          ''')
+
+        self.assert_nm({'engreen': '''[connection]
+id=netplan-engreen
+type=ethernet
+interface-name=engreen
+
+[ethernet]
+wake-on-lan=0
+
+[ipv4]
+method=manual
+address1=192.168.14.2/24
+routing-rule1=priority 99 to 10.10.10.0/24 iif if0 table 100
+
 [ipv6]
 method=ignore
 '''})