netlink: rework containers

Instead of representing containers as several arrays, make a new
netlink_container struct and keep one array of these structs. We
also introduce netlink_attribute structs that in the future will
hold meta-information about each atribute.

2 files changed, 69 insertions, 63 deletions

diff --git a/src/libsystemd/sd-netlink/netlink-internal.h b/src/libsystemd/sd-netlink/netlink-internal.h
index 31bc1d3fbd..5773f61165 100644
--- a/src/libsystemd/sd-netlink/netlink-internal.h
+++ b/src/libsystemd/sd-netlink/netlink-internal.h
@@ -92,18 +92,26 @@ struct sd_netlink {
         sd_event *event;
 };
 
+struct netlink_attribute {
+        size_t offset; /* offset from hdr to attirubte */
+};
+
+struct netlink_container {
+        const struct NLTypeSystem *type_system; /* the type system of the container */
+        size_t offset; /* offset from hdr to the start of the container */
+        struct netlink_attribute *attributes;
+        unsigned short n_attributes; /* number of attributes in container */
+};
+
 struct sd_netlink_message {
         RefCount n_ref;
 
         sd_netlink *rtnl;
 
         struct nlmsghdr *hdr;
-        const struct NLTypeSystem *(container_type_system[RTNL_CONTAINER_DEPTH]); /* the type of the container and all its parents */
-        size_t container_offsets[RTNL_CONTAINER_DEPTH]; /* offset from hdr to each container's start */
+        struct netlink_container containers[RTNL_CONTAINER_DEPTH];
         unsigned n_containers; /* number of containers */
         size_t next_rta_offset; /* offset from hdr to next rta */
-        size_t *rta_offset_tb[RTNL_CONTAINER_DEPTH];
-        unsigned short rta_tb_size[RTNL_CONTAINER_DEPTH];
         bool sealed:1;
         bool broadcast:1;
 
diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c
index 23f369c576..13573dcea8 100644
--- a/src/libsystemd/sd-netlink/netlink-message.c
+++ b/src/libsystemd/sd-netlink/netlink-message.c
@@ -34,7 +34,7 @@
 #include "netlink-internal.h"
 #include "netlink-types.h"
 
-#define GET_CONTAINER(m, i) ((i) < (m)->n_containers ? (struct rtattr*)((uint8_t*)(m)->hdr + (m)->container_offsets[i]) : NULL)
+#define GET_CONTAINER(m, i) ((i) < (m)->n_containers ? (struct rtattr*)((uint8_t*)(m)->hdr + (m)->containers[i].offset) : NULL)
 #define PUSH_CONTAINER(m, new) (m)->container_offsets[(m)->n_containers ++] = (uint8_t*)(new) - (uint8_t*)(m)->hdr;
 
 #define RTA_TYPE(rta) ((rta)->rta_type & NLA_TYPE_MASK)
@@ -88,7 +88,7 @@ int message_new(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t type) {
 
         m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
 
-        type_get_type_system(nl_type, &m->container_type_system[0]);
+        type_get_type_system(nl_type, &m->containers[0].type_system);
         m->hdr->nlmsg_len = size;
         m->hdr->nlmsg_type = type;
 
@@ -129,7 +129,7 @@ sd_netlink_message *sd_netlink_message_unref(sd_netlink_message *m) {
                 free(m->hdr);
 
                 for (i = 0; i <= m->n_containers; i++)
-                        free(m->rta_offset_tb[i]);
+                        free(m->containers[i].attributes);
 
                 sd_netlink_message_unref(m->next);
 
@@ -223,7 +223,7 @@ static int message_attribute_has_type(sd_netlink_message *m, size_t *out_size, u
 
         assert(m);
 
-        r = type_system_get_type(m->container_type_system[m->n_containers], &type, attribute_type);
+        r = type_system_get_type(m->containers[m->n_containers].type_system, &type, attribute_type);
         if (r < 0)
                 return r;
 
@@ -406,18 +406,18 @@ int sd_netlink_message_open_container(sd_netlink_message *m, unsigned short type
                 if (r < 0)
                         return r;
 
-                r = type_system_get_type_system_union(m->container_type_system[m->n_containers], &type_system_union, type);
+                r = type_system_get_type_system_union(m->containers[m->n_containers].type_system, &type_system_union, type);
                 if (r < 0)
                         return r;
 
                 r = type_system_union_protocol_get_type_system(type_system_union,
-                                                               &m->container_type_system[m->n_containers + 1],
+                                                               &m->containers[m->n_containers + 1].type_system,
                                                                family);
                 if (r < 0)
                         return r;
         } else {
-                r = type_system_get_type_system(m->container_type_system[m->n_containers],
-                                                &m->container_type_system[m->n_containers + 1],
+                r = type_system_get_type_system(m->containers[m->n_containers].type_system,
+                                                &m->containers[m->n_containers + 1].type_system,
                                                 type);
                 if (r < 0)
                         return r;
@@ -427,7 +427,7 @@ int sd_netlink_message_open_container(sd_netlink_message *m, unsigned short type
         if (r < 0)
                 return r;
 
-        m->container_offsets[m->n_containers ++] = r;
+        m->containers[m->n_containers ++].offset = r;
 
         return 0;
 }
@@ -439,12 +439,12 @@ int sd_netlink_message_open_container_union(sd_netlink_message *m, unsigned shor
         assert_return(m, -EINVAL);
         assert_return(!m->sealed, -EPERM);
 
-        r = type_system_get_type_system_union(m->container_type_system[m->n_containers], &type_system_union, type);
+        r = type_system_get_type_system_union(m->containers[m->n_containers].type_system, &type_system_union, type);
         if (r < 0)
                 return r;
 
         r = type_system_union_get_type_system(type_system_union,
-                                              &m->container_type_system[m->n_containers + 1],
+                                              &m->containers[m->n_containers + 1].type_system,
                                               key);
         if (r < 0)
                 return r;
@@ -458,7 +458,7 @@ int sd_netlink_message_open_container_union(sd_netlink_message *m, unsigned shor
         if (r < 0)
                 return r;
 
-        m->container_offsets[m->n_containers ++] = r;
+        m->containers[m->n_containers ++].offset = r;
 
         return 0;
 }
@@ -469,26 +469,29 @@ int sd_netlink_message_close_container(sd_netlink_message *m) {
         assert_return(!m->sealed, -EPERM);
         assert_return(m->n_containers > 0, -EINVAL);
 
-        m->container_type_system[m->n_containers] = NULL;
+        m->containers[m->n_containers].type_system = NULL;
         m->n_containers --;
 
         return 0;
 }
 
 static int netlink_message_read_internal(sd_netlink_message *m, unsigned short type, void **data) {
+        struct netlink_attribute *attribute;
         struct rtattr *rta;
 
         assert_return(m, -EINVAL);
         assert_return(m->sealed, -EPERM);
         assert_return(data, -EINVAL);
         assert(m->n_containers <= RTNL_CONTAINER_DEPTH);
-        assert(m->rta_offset_tb[m->n_containers]);
-        assert(type < m->rta_tb_size[m->n_containers]);
+        assert(m->containers[m->n_containers].attributes);
+        assert(type < m->containers[m->n_containers].n_attributes);
 
-        if(!m->rta_offset_tb[m->n_containers][type])
+        attribute = &m->containers[m->n_containers].attributes[type];
+
+        if(!attribute->offset)
                 return -ENODATA;
 
-        rta = (struct rtattr*)((uint8_t *) m->hdr + m->rta_offset_tb[m->n_containers][type]);
+        rta = (struct rtattr*)((uint8_t *) m->hdr + attribute->offset);
 
         *data = RTA_DATA(rta);
 
@@ -671,37 +674,36 @@ int sd_netlink_message_read_in6_addr(sd_netlink_message *m, unsigned short type,
         return 0;
 }
 
-static int netlink_message_parse(sd_netlink_message *m,
-                       size_t **rta_offset_tb,
-                       unsigned short *rta_tb_size,
-                       int count,
-                       struct rtattr *rta,
-                       unsigned int rt_len) {
-        unsigned short type;
-        size_t *tb;
+static int netlink_container_parse(sd_netlink_message *m,
+                                   struct netlink_container *container,
+                                   int count,
+                                   struct rtattr *rta,
+                                   unsigned int rt_len) {
+        _cleanup_free_ struct netlink_attribute *attributes = NULL;
 
-        tb = new0(size_t, count);
-        if(!tb)
+        attributes = new0(struct netlink_attribute, count);
+        if(!attributes)
                 return -ENOMEM;
 
-        *rta_tb_size = count;
-
         for (; RTA_OK(rta, rt_len); rta = RTA_NEXT(rta, rt_len)) {
+                unsigned short type;
+
                 type = RTA_TYPE(rta);
 
                 /* if the kernel is newer than the headers we used
-                   when building, we ignore out-of-range attributes
-                 */
+                   when building, we ignore out-of-range attributes */
                 if (type >= count)
                         continue;
 
-                if (tb[type])
+                if (attributes[type].offset)
                         log_debug("rtnl: message parse - overwriting repeated attribute");
 
-                tb[type] = (uint8_t *) rta - (uint8_t *) m->hdr;
+                attributes[type].offset = (uint8_t *) rta - (uint8_t *) m->hdr;
         }
 
-        *rta_offset_tb = tb;
+        container->attributes = attributes;
+        attributes = NULL;
+        container->n_attributes = count;
 
         return 0;
 }
@@ -717,7 +719,7 @@ int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short typ
         assert_return(m, -EINVAL);
         assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -EINVAL);
 
-        r = type_system_get_type(m->container_type_system[m->n_containers],
+        r = type_system_get_type(m->containers[m->n_containers].type_system,
                                  &nl_type,
                                  type_id);
         if (r < 0)
@@ -726,7 +728,7 @@ int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short typ
         type = type_get_type(nl_type);
 
         if (type == NETLINK_TYPE_NESTED) {
-                r = type_system_get_type_system(m->container_type_system[m->n_containers],
+                r = type_system_get_type_system(m->containers[m->n_containers].type_system,
                                                 &type_system,
                                                 type_id);
                 if (r < 0)
@@ -734,7 +736,7 @@ int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short typ
         } else if (type == NETLINK_TYPE_UNION) {
                 const NLTypeSystemUnion *type_system_union;
 
-                r = type_system_get_type_system_union(m->container_type_system[m->n_containers],
+                r = type_system_get_type_system_union(m->containers[m->n_containers].type_system,
                                                       &type_system_union,
                                                       type_id);
                 if (r < 0)
@@ -787,18 +789,17 @@ int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short typ
 
         m->n_containers ++;
 
-        r = netlink_message_parse(m,
-                                  &m->rta_offset_tb[m->n_containers],
-                                  &m->rta_tb_size[m->n_containers],
-                                  type_system_get_count(type_system),
-                                  container,
-                                  size);
+        r = netlink_container_parse(m,
+                                    &m->containers[m->n_containers],
+                                    type_system_get_count(type_system),
+                                    container,
+                                    size);
         if (r < 0) {
                 m->n_containers --;
                 return r;
         }
 
-        m->container_type_system[m->n_containers] = type_system;
+        m->containers[m->n_containers].type_system = type_system;
 
         return 0;
 }
@@ -808,9 +809,9 @@ int sd_netlink_message_exit_container(sd_netlink_message *m) {
         assert_return(m->sealed, -EINVAL);
         assert_return(m->n_containers > 0, -EINVAL);
 
-        free(m->rta_offset_tb[m->n_containers]);
-        m->rta_offset_tb[m->n_containers] = NULL;
-        m->container_type_system[m->n_containers] = NULL;
+        free(m->containers[m->n_containers].attributes);
+        m->containers[m->n_containers].attributes = NULL;
+        m->containers[m->n_containers].type_system = NULL;
 
         m->n_containers --;
 
@@ -859,15 +860,13 @@ int sd_netlink_message_rewind(sd_netlink_message *m) {
                 rtnl_message_seal(m);
 
         for (i = 1; i <= m->n_containers; i++) {
-                free(m->rta_offset_tb[i]);
-                m->rta_offset_tb[i] = NULL;
-                m->rta_tb_size[i] = 0;
-                m->container_type_system[i] = NULL;
+                free(m->containers[i].attributes);
+                m->containers[i].attributes = NULL;
         }
 
         m->n_containers = 0;
 
-        if (m->rta_offset_tb[0]) {
+        if (m->containers[0].attributes) {
                 /* top-level attributes have already been parsed */
                 return 0;
         }
@@ -886,14 +885,13 @@ int sd_netlink_message_rewind(sd_netlink_message *m) {
 
                 type_get_type_system(nl_type, &type_system);
 
-                m->container_type_system[0] = type_system;
+                m->containers[0].type_system = type_system;
 
-                r = netlink_message_parse(m,
-                                          &m->rta_offset_tb[m->n_containers],
-                                          &m->rta_tb_size[m->n_containers],
-                                          type_system_get_count(type_system),
-                                          (struct rtattr*)((uint8_t*)NLMSG_DATA(m->hdr) + NLMSG_ALIGN(size)),
-                                          NLMSG_PAYLOAD(m->hdr, size));
+                r = netlink_container_parse(m,
+                                            &m->containers[m->n_containers],
+                                            type_system_get_count(type_system),
+                                            (struct rtattr*)((uint8_t*)NLMSG_DATA(m->hdr) + NLMSG_ALIGN(size)),
+                                            NLMSG_PAYLOAD(m->hdr, size));
                 if (r < 0)
                         return r;
         }