Merge pull request #1269 from zonque/netcls

cgroup: add support for net_cls controllers

man/systemd.unit.xml

@@ -1044,6 +1044,20 @@
         files. This functionality should not be used in normal
         units.</para></listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><varname>NetClass=</varname></term>
+        <listitem><para>Configures a network class number to assign to the
+        unit. This value will be set to the
+        <literal>net_cls.class_id</literal> property of the
+        <literal>net_cls</literal> cgroup of the unit. The directive
+        accepts a numerical value (for fixed number assignment) and the keyword
+        <literal>auto</literal> (for dynamic allocation). Network traffic of
+        all processes inside the unit will have the network class ID assigned
+        by the kernel. Also see
+        <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+        .</para></listitem>
+      </varlistentry>
     </variablelist>
 
   </refsect1>

src/basic/cgroup-util.c

@@ -2254,6 +2254,7 @@ static const char *cgroup_controller_table[_CGROUP_CONTROLLER_MAX] = {
         [CGROUP_CONTROLLER_MEMORY] = "memory",
         [CGROUP_CONTROLLER_DEVICES] = "devices",
         [CGROUP_CONTROLLER_PIDS] = "pids",
+        [CGROUP_CONTROLLER_NET_CLS] = "net_cls",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(cgroup_controller, CGroupController);

src/basic/cgroup-util.h

@@ -36,6 +36,7 @@ typedef enum CGroupController {
         CGROUP_CONTROLLER_MEMORY,
         CGROUP_CONTROLLER_DEVICES,
         CGROUP_CONTROLLER_PIDS,
+        CGROUP_CONTROLLER_NET_CLS,
         _CGROUP_CONTROLLER_MAX,
         _CGROUP_CONTROLLER_INVALID = -1,
 } CGroupController;
@@ -50,6 +51,7 @@ typedef enum CGroupMask {
         CGROUP_MASK_MEMORY = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_MEMORY),
         CGROUP_MASK_DEVICES = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_DEVICES),
         CGROUP_MASK_PIDS = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_PIDS),
+        CGROUP_MASK_NET_CLS = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_NET_CLS),
         _CGROUP_MASK_ALL = CGROUP_CONTROLLER_TO_MASK(_CGROUP_CONTROLLER_MAX) - 1
 } CGroupMask;
 

src/core/cgroup.c

@@ -47,6 +47,8 @@ void cgroup_context_init(CGroupContext *c) {
         c->startup_blockio_weight = CGROUP_BLKIO_WEIGHT_INVALID;
 
         c->tasks_max = (uint64_t) -1;
+
+        c->netclass_type = CGROUP_NETCLASS_TYPE_NONE;
 }
 
 void cgroup_context_free_device_allow(CGroupContext *c, CGroupDeviceAllow *a) {
@@ -291,7 +293,7 @@ fail:
         return -errno;
 }
 
-void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, ManagerState state) {
+void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, uint32_t netclass, ManagerState state) {
         bool is_root;
         int r;
 
@@ -489,6 +491,17 @@ void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, M
                         log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
                                        "Failed to set pids.max on %s: %m", path);
         }
+
+        if (mask & CGROUP_MASK_NET_CLS) {
+                char buf[DECIMAL_STR_MAX(uint32_t)];
+
+                sprintf(buf, "%" PRIu32, netclass);
+
+                r = cg_set_attribute("net_cls", path, "net_cls.classid", buf);
+                if (r < 0)
+                        log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
+                                       "Failed to set net_cls.classid on %s: %m", path);
+        }
 }
 
 CGroupMask cgroup_context_get_mask(CGroupContext *c) {
@@ -521,6 +534,9 @@ CGroupMask cgroup_context_get_mask(CGroupContext *c) {
             c->tasks_max != (uint64_t) -1)
                 mask |= CGROUP_MASK_PIDS;
 
+        if (c->netclass_type != CGROUP_NETCLASS_TYPE_NONE)
+                mask |= CGROUP_MASK_NET_CLS;
+
         return mask;
 }
 
@@ -888,6 +904,103 @@ static bool unit_has_mask_realized(Unit *u, CGroupMask target_mask) {
         return u->cgroup_realized && u->cgroup_realized_mask == target_mask;
 }
 
+static int unit_find_free_netclass_cgroup(Unit *u, uint32_t *ret) {
+
+        uint32_t start, i;
+        Manager *m;
+
+        assert(u);
+
+        m = u->manager;
+
+        i = start = m->cgroup_netclass_registry_last;
+
+        do {
+                i++;
+
+                if (!hashmap_get(m->cgroup_netclass_registry, UINT_TO_PTR(i))) {
+                        m->cgroup_netclass_registry_last = i;
+                        *ret = i;
+                        return 0;
+                }
+
+                if (i == UINT32_MAX)
+                        i = CGROUP_NETCLASS_FIXED_MAX;
+
+        } while (i != start);
+
+        return -ENOBUFS;
+}
+
+int unit_add_to_netclass_cgroup(Unit *u) {
+
+        CGroupContext *cc;
+        Unit *first;
+        void *key;
+        int r;
+
+        assert(u);
+
+        cc = unit_get_cgroup_context(u);
+        if (!cc)
+                return 0;
+
+        switch (cc->netclass_type) {
+        case CGROUP_NETCLASS_TYPE_NONE:
+                return 0;
+
+        case CGROUP_NETCLASS_TYPE_FIXED:
+                u->cgroup_netclass_id = cc->netclass_id;
+                break;
+
+        case CGROUP_NETCLASS_TYPE_AUTO:
+                /* Allocate a new ID in case it was requested and not done yet */
+                if (u->cgroup_netclass_id == 0) {
+                        r = unit_find_free_netclass_cgroup(u, &u->cgroup_netclass_id);
+                        if (r < 0)
+                                return r;
+
+                        log_debug("Dynamically assigned netclass cgroup id %" PRIu32 " to %s", u->cgroup_netclass_id, u->id);
+                }
+
+                break;
+        }
+
+        r = hashmap_ensure_allocated(&u->manager->cgroup_netclass_registry, &trivial_hash_ops);
+        if (r < 0)
+                return r;
+
+        key = UINT32_TO_PTR(u->cgroup_netclass_id);
+        first = hashmap_get(u->manager->cgroup_netclass_registry, key);
+
+        if (first) {
+                LIST_PREPEND(cgroup_netclass, first, u);
+                return hashmap_replace(u->manager->cgroup_netclass_registry, key, u);
+        }
+
+        return hashmap_put(u->manager->cgroup_netclass_registry, key, u);
+}
+
+int unit_remove_from_netclass_cgroup(Unit *u) {
+
+        Unit *head;
+        void *key;
+
+        assert(u);
+
+        key = UINT32_TO_PTR(u->cgroup_netclass_id);
+
+        LIST_FIND_HEAD(cgroup_netclass, u, head);
+        LIST_REMOVE(cgroup_netclass, head, u);
+
+        if (head)
+                return hashmap_replace(u->manager->cgroup_netclass_registry, key, head);
+
+        hashmap_remove(u->manager->cgroup_netclass_registry, key);
+
+        return 0;
+}
+
 /* Check if necessary controllers and attributes for a unit are in place.
  *
  * If so, do nothing.
@@ -923,7 +1036,7 @@ static int unit_realize_cgroup_now(Unit *u, ManagerState state) {
                 return r;
 
         /* Finally, apply the necessary attributes. */
-        cgroup_context_apply(unit_get_cgroup_context(u), target_mask, u->cgroup_path, state);
+        cgroup_context_apply(unit_get_cgroup_context(u), target_mask, u->cgroup_path, u->cgroup_netclass_id, state);
 
         return 0;
 }

src/core/cgroup.h

@@ -26,6 +26,11 @@
 #include "list.h"
 #include "time-util.h"
 
+/* Maximum value for fixed (manual) net class ID assignment,
+ * and also the value at which the range of automatic assignments starts
+ */
+#define CGROUP_NETCLASS_FIXED_MAX UINT32_C(65535)
+
 typedef struct CGroupContext CGroupContext;
 typedef struct CGroupDeviceAllow CGroupDeviceAllow;
 typedef struct CGroupBlockIODeviceWeight CGroupBlockIODeviceWeight;
@@ -47,6 +52,17 @@ typedef enum CGroupDevicePolicy {
         _CGROUP_DEVICE_POLICY_INVALID = -1
 } CGroupDevicePolicy;
 
+typedef enum CGroupNetClassType {
+        /* Default - do not assign a net class */
+        CGROUP_NETCLASS_TYPE_NONE,
+
+        /* Automatically assign a net class */
+        CGROUP_NETCLASS_TYPE_AUTO,
+
+        /* Assign the net class that was provided by the user */
+        CGROUP_NETCLASS_TYPE_FIXED,
+} CGroupNetClassType;
+
 struct CGroupDeviceAllow {
         LIST_FIELDS(CGroupDeviceAllow, device_allow);
         char *path;
@@ -88,6 +104,9 @@ struct CGroupContext {
         CGroupDevicePolicy device_policy;
         LIST_HEAD(CGroupDeviceAllow, device_allow);
 
+        CGroupNetClassType netclass_type;
+        uint32_t netclass_id;
+
         uint64_t tasks_max;
 
         bool delegate;
@@ -99,7 +118,7 @@ struct CGroupContext {
 void cgroup_context_init(CGroupContext *c);
 void cgroup_context_done(CGroupContext *c);
 void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix);
-void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, ManagerState state);
+void cgroup_context_apply(CGroupContext *c, CGroupMask mask, const char *path, uint32_t netclass_id, ManagerState state);
 
 CGroupMask cgroup_context_get_mask(CGroupContext *c);
 
@@ -127,6 +146,9 @@ int unit_watch_cgroup(Unit *u);
 
 int unit_attach_pids_to_cgroup(Unit *u);
 
+int unit_add_to_netclass_cgroup(Unit *u);
+int unit_remove_from_netclass_cgroup(Unit *u);
+
 int manager_setup_cgroup(Manager *m);
 void manager_shutdown_cgroup(Manager *m, bool delete);
 

src/core/dbus-unit.c

@@ -679,6 +679,7 @@ const sd_bus_vtable bus_unit_vtable[] = {
         SD_BUS_PROPERTY("Asserts", "a(sbbsi)", property_get_conditions, offsetof(Unit, asserts), 0),
         SD_BUS_PROPERTY("LoadError", "(ss)", property_get_load_error, 0, SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("Transient", "b", bus_property_get_bool, offsetof(Unit, transient), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("NetClass", "u", bus_property_get_unsigned, offsetof(Unit, cgroup_netclass_id), 0),
 
         SD_BUS_METHOD("Start", "s", "o", method_start, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("Stop", "s", "o", method_stop, SD_BUS_VTABLE_UNPRIVILEGED),

src/core/load-fragment-gperf.gperf.m4

@@ -126,7 +126,8 @@ $1.BlockIOReadBandwidth,         config_parse_blockio_bandwidth,     0,
 $1.BlockIOWriteBandwidth,        config_parse_blockio_bandwidth,     0,                             offsetof($1, cgroup_context)
 $1.TasksAccounting,              config_parse_bool,                  0,                             offsetof($1, cgroup_context.tasks_accounting)
 $1.TasksMax,                     config_parse_tasks_max,             0,                             offsetof($1, cgroup_context)
-$1.Delegate,                     config_parse_bool,                  0,                             offsetof($1, cgroup_context.delegate)'
+$1.Delegate,                     config_parse_bool,                  0,                             offsetof($1, cgroup_context.delegate)
+$1.NetClass,                     config_parse_netclass,              0,                             offsetof($1, cgroup_context)'
 )m4_dnl
 Unit.Description,                config_parse_unit_string_printf,    0,                             offsetof(Unit, description)
 Unit.Documentation,              config_parse_documentation,         0,                             offsetof(Unit, documentation)

src/core/load-fragment.c

@@ -2962,6 +2962,48 @@ int config_parse_blockio_bandwidth(
         return 0;
 }
 
+int config_parse_netclass(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        CGroupContext *c = data;
+        unsigned v;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        if (streq(rvalue, "auto")) {
+                c->netclass_type = CGROUP_NETCLASS_TYPE_AUTO;
+                return 0;
+        }
+
+        r = safe_atou32(rvalue, &v);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL,
+                           "Netclass '%s' invalid. Ignoring.", rvalue);
+                return 0;
+        }
+
+        if (v > CGROUP_NETCLASS_FIXED_MAX)
+                log_syntax(unit, LOG_ERR, filename, line, EINVAL,
+                           "Fixed netclass %" PRIu32 " out of allowed range (0-%d). Applying anyway.", v, (uint32_t) CGROUP_NETCLASS_FIXED_MAX);
+
+        c->netclass_id = v;
+        c->netclass_type = CGROUP_NETCLASS_TYPE_FIXED;
+
+        return 0;
+}
+
 DEFINE_CONFIG_PARSE_ENUM(config_parse_job_mode, job_mode, JobMode, "Failed to parse job mode");
 
 int config_parse_job_mode_isolate(

src/core/load-fragment.h

@@ -90,6 +90,7 @@ int config_parse_device_allow(const char *unit, const char *filename, unsigned l
 int config_parse_blockio_weight(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_blockio_device_weight(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_blockio_bandwidth(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_netclass(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_job_mode(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_job_mode_isolate(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_exec_selinux_context(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);

src/core/manager.c

@@ -579,6 +579,8 @@ int manager_new(ManagerRunningAs running_as, bool test_run, Manager **_m) {
         m->have_ask_password = -EINVAL; /* we don't know */
         m->first_boot = -1;
 
+        m->cgroup_netclass_registry_last = CGROUP_NETCLASS_FIXED_MAX;
+
         m->test_run = test_run;
 
         /* Reboot immediately if the user hits C-A-D more often than 7x per 2s */
@@ -960,6 +962,8 @@ Manager* manager_free(Manager *m) {
         hashmap_free(m->cgroup_unit);
         set_free_free(m->unit_path_cache);
 
+        hashmap_free(m->cgroup_netclass_registry);
+
         free(m->switch_root);
         free(m->switch_root_init);
 

src/core/manager.h

@@ -303,6 +303,10 @@ struct Manager {
         const char *unit_log_format_string;
 
         int first_boot;
+
+        /* Used for NetClass=auto units */
+        Hashmap *cgroup_netclass_registry;
+        uint32_t cgroup_netclass_registry_last;
 };
 
 int manager_new(ManagerRunningAs running_as, bool test_run, Manager **m);

src/core/unit.c

@@ -452,6 +452,7 @@ static void unit_free_requires_mounts_for(Unit *u) {
 static void unit_done(Unit *u) {
         ExecContext *ec;
         CGroupContext *cc;
+        int r;
 
         assert(u);
 
@@ -468,6 +469,10 @@ static void unit_done(Unit *u) {
         cc = unit_get_cgroup_context(u);
         if (cc)
                 cgroup_context_done(cc);
+
+        r = unit_remove_from_netclass_cgroup(u);
+        if (r < 0)
+                log_warning_errno(r, "Unable to remove unit from netclass group: %m");
 }
 
 void unit_free(Unit *u) {
@@ -1241,6 +1246,14 @@ int unit_load(Unit *u) {
                 }
 
                 unit_update_cgroup_members_masks(u);
+
+                /* If we are reloading, we need to wait for the deserializer
+                 * to restore the net_cls ids that have been set previously */
+                if (u->manager->n_reloading <= 0) {
+                        r = unit_add_to_netclass_cgroup(u);
+                        if (r < 0)
+                                return r;
+                }
         }
 
         assert((u->load_state != UNIT_MERGED) == !u->merged_into);
@@ -2591,6 +2604,9 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
                 unit_serialize_item(u, f, "cgroup", u->cgroup_path);
         unit_serialize_item(u, f, "cgroup-realized", yes_no(u->cgroup_realized));
 
+        if (u->cgroup_netclass_id)
+                unit_serialize_item_format(u, f, "netclass-id", "%" PRIu32, u->cgroup_netclass_id);
+
         if (serialize_jobs) {
                 if (u->job) {
                         fprintf(f, "job\n");
@@ -2777,6 +2793,17 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
                         else
                                 u->cgroup_realized = b;
 
+                        continue;
+                } else if (streq(l, "netclass-id")) {
+                        r = safe_atou32(v, &u->cgroup_netclass_id);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to parse netclass ID %s, ignoring.", v);
+                        else {
+                                r = unit_add_to_netclass_cgroup(u);
+                                if (r < 0)
+                                        log_unit_debug_errno(u, r, "Failed to add unit to netclass cgroup, ignoring: %m");
+                        }
+
                         continue;
                 }
 

src/core/unit.h

@@ -161,6 +161,9 @@ struct Unit {
         /* CGroup realize members queue */
         LIST_FIELDS(Unit, cgroup_queue);
 
+        /* Units with the same CGroup netclass */
+        LIST_FIELDS(Unit, cgroup_netclass);
+
         /* PIDs we keep an eye on. Note that a unit might have many
          * more, but these are the ones we care enough about to
          * process SIGCHLD for */
@@ -189,6 +192,8 @@ struct Unit {
         CGroupMask cgroup_members_mask;
         int cgroup_inotify_wd;
 
+        uint32_t cgroup_netclass_id;
+
         /* How to start OnFailure units */
         JobMode on_failure_job_mode;