datapath: Refine Netlink message size calculation and kill FLOW_BUFSIZE

Kills the FLOW_BUFSIZE constant which needs to be calculated manually
and replaces it with key_attr_size() based on nla_total_size().
Calculates the size of datapath messages instead of relying on
NLMSG_DEFAULT_SIZE and moves the existing message size calculations
into own functions for clarity.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Jesse Gross <jesse@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index aae507d..40b25e5 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -338,6 +338,43 @@ static int queue_gso_packets(struct net *net, int dp_ifindex,
        return err;
 }
 
+static size_t key_attr_size(void)
+{
+       return    nla_total_size(4)   /* OVS_KEY_ATTR_PRIORITY */
+               + nla_total_size(0)   /* OVS_KEY_ATTR_TUNNEL */
+                 + nla_total_size(8)   /* OVS_TUNNEL_KEY_ATTR_ID */
+                 + nla_total_size(4)   /* OVS_TUNNEL_KEY_ATTR_IPV4_SRC */
+                 + nla_total_size(4)   /* OVS_TUNNEL_KEY_ATTR_IPV4_DST */
+                 + nla_total_size(1)   /* OVS_TUNNEL_KEY_ATTR_TOS */
+                 + nla_total_size(1)   /* OVS_TUNNEL_KEY_ATTR_TTL */
+                 + nla_total_size(0)   /* OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT */
+                 + nla_total_size(0)   /* OVS_TUNNEL_KEY_ATTR_CSUM */
+               + nla_total_size(4)   /* OVS_KEY_ATTR_IN_PORT */
+               + nla_total_size(4)   /* OVS_KEY_ATTR_SKB_MARK */
+               + nla_total_size(12)  /* OVS_KEY_ATTR_ETHERNET */
+               + nla_total_size(2)   /* OVS_KEY_ATTR_ETHERTYPE */
+               + nla_total_size(4)   /* OVS_KEY_ATTR_8021Q */
+               + nla_total_size(0)   /* OVS_KEY_ATTR_ENCAP */
+               + nla_total_size(2)   /* OVS_KEY_ATTR_ETHERTYPE */
+               + nla_total_size(40)  /* OVS_KEY_ATTR_IPV6 */
+               + nla_total_size(2)   /* OVS_KEY_ATTR_ICMPV6 */
+               + nla_total_size(28); /* OVS_KEY_ATTR_ND */
+}
+
+static size_t upcall_msg_size(const struct sk_buff *skb,
+                             const struct nlattr *userdata)
+{
+       size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
+               + nla_total_size(skb->len) /* OVS_PACKET_ATTR_PACKET */
+               + nla_total_size(key_attr_size()); /* OVS_PACKET_ATTR_KEY */
+
+       /* OVS_PACKET_ATTR_USERDATA */
+       if (userdata)
+               size += NLA_ALIGN(userdata->nla_len);
+
+       return size;
+}
+
 static int queue_userspace_packet(struct net *net, int dp_ifindex,
                                  struct sk_buff *skb,
                                  const struct dp_upcall_info *upcall_info)
@@ -346,7 +383,6 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex,
        struct sk_buff *nskb = NULL;
        struct sk_buff *user_skb; /* to be queued to userspace */
        struct nlattr *nla;
-       unsigned int len;
        int err;
 
        if (vlan_tx_tag_present(skb)) {
@@ -366,13 +402,7 @@ static int queue_userspace_packet(struct net *net, int dp_ifindex,
                goto out;
        }
 
-       len = sizeof(struct ovs_header);
-       len += nla_total_size(skb->len);
-       len += nla_total_size(FLOW_BUFSIZE);
-       if (upcall_info->userdata)
-               len += NLA_ALIGN(upcall_info->userdata->nla_len);
-
-       user_skb = genlmsg_new(len, GFP_ATOMIC);
+       user_skb = genlmsg_new(upcall_msg_size(skb, upcall_info->userdata), GFP_ATOMIC);
        if (!user_skb) {
                err = -ENOMEM;
                goto out;
@@ -1045,6 +1075,16 @@ static int actions_to_attr(const struct nlattr *attr, int len, struct sk_buff *s
        return 0;
 }
 
+static size_t ovs_flow_cmd_msg_size(const struct sw_flow_actions *acts)
+{
+       return NLMSG_ALIGN(sizeof(struct ovs_header))
+               + nla_total_size(key_attr_size()) /* OVS_FLOW_ATTR_KEY */
+               + nla_total_size(sizeof(struct ovs_flow_stats)) /* OVS_FLOW_ATTR_STATS */
+               + nla_total_size(1) /* OVS_FLOW_ATTR_TCP_FLAGS */
+               + nla_total_size(8) /* OVS_FLOW_ATTR_USED */
+               + nla_total_size(acts->actions_len); /* OVS_FLOW_ATTR_ACTIONS */
+}
+
 /* Called with genl_lock. */
 static int ovs_flow_cmd_fill_info(struct sw_flow *flow, struct datapath *dp,
                                  struct sk_buff *skb, u32 portid,
@@ -1133,25 +1173,11 @@ error:
 static struct sk_buff *ovs_flow_cmd_alloc_info(struct sw_flow *flow)
 {
        const struct sw_flow_actions *sf_acts;
-       int len;
 
        sf_acts = rcu_dereference_protected(flow->sf_acts,
                                            lockdep_genl_is_held());
 
-       /* OVS_FLOW_ATTR_KEY */
-       len = nla_total_size(FLOW_BUFSIZE);
-       /* OVS_FLOW_ATTR_ACTIONS */
-       len += nla_total_size(sf_acts->actions_len);
-       /* OVS_FLOW_ATTR_STATS */
-       len += nla_total_size(sizeof(struct ovs_flow_stats));
-       /* OVS_FLOW_ATTR_TCP_FLAGS */
-       len += nla_total_size(1);
-       /* OVS_FLOW_ATTR_USED */
-       len += nla_total_size(8);
-
-       len += NLMSG_ALIGN(sizeof(struct ovs_header));
-
-       return genlmsg_new(len, GFP_KERNEL);
+       return genlmsg_new(ovs_flow_cmd_msg_size(sf_acts), GFP_KERNEL);
 }
 
 static struct sk_buff *ovs_flow_cmd_build_info(struct sw_flow *flow,
@@ -1452,6 +1478,16 @@ static struct genl_multicast_group ovs_dp_datapath_multicast_group = {
        .name = OVS_DATAPATH_MCGROUP
 };
 
+static size_t ovs_dp_cmd_msg_size(void)
+{
+       size_t msgsize = NLMSG_ALIGN(sizeof(struct ovs_header));
+
+       msgsize += nla_total_size(IFNAMSIZ);
+       msgsize += nla_total_size(sizeof(struct ovs_dp_stats));
+
+       return msgsize;
+}
+
 static int ovs_dp_cmd_fill_info(struct datapath *dp, struct sk_buff *skb,
                                u32 portid, u32 seq, u32 flags, u8 cmd)
 {
@@ -1490,7 +1526,7 @@ static struct sk_buff *ovs_dp_cmd_build_info(struct datapath *dp, u32 portid,
        struct sk_buff *skb;
        int retval;
 
-       skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+       skb = genlmsg_new(ovs_dp_cmd_msg_size(), GFP_KERNEL);
        if (!skb)
                return ERR_PTR(-ENOMEM);
 

diff --git a/datapath/flow.h b/datapath/flow.h
index c4b9c4f..dba66cf 100644 (file)
--- a/datapath/flow.h
+++ b/datapath/flow.h
@@ -158,35 +158,6 @@ int ovs_flow_extract(struct sk_buff *, u16 in_port, struct sw_flow_key *,
 void ovs_flow_used(struct sw_flow *, struct sk_buff *);
 u64 ovs_flow_used_time(unsigned long flow_jiffies);
 
-/* Upper bound on the length of a nlattr-formatted flow key.  The longest
- * nlattr-formatted flow key would be:
- *
- *                                     struct  pad  nl hdr  total
- *                                     ------  ---  ------  -----
- *  OVS_KEY_ATTR_PRIORITY                4    --     4      8
- *  OVS_KEY_ATTR_TUNNEL                  0    --     4      4
- *  - OVS_TUNNEL_KEY_ATTR_ID             8    --     4     12
- *  - OVS_TUNNEL_KEY_ATTR_IPV4_SRC       4    --     4      8
- *  - OVS_TUNNEL_KEY_ATTR_IPV4_DST       4    --     4      8
- *  - OVS_TUNNEL_KEY_ATTR_TOS            1    3      4      8
- *  - OVS_TUNNEL_KEY_ATTR_TTL            1    3      4      8
- *  - OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT  0    --     4      4
- *  - OVS_TUNNEL_KEY_ATTR_CSUM           0    --     4      4
- *  OVS_KEY_ATTR_IN_PORT                 4    --     4      8
- *  OVS_KEY_ATTR_SKB_MARK                4    --     4      8
- *  OVS_KEY_ATTR_ETHERNET               12    --     4     16
- *  OVS_KEY_ATTR_ETHERTYPE               2     2     4      8  (outer VLAN ethertype)
- *  OVS_KEY_ATTR_8021Q                   4    --     4      8
- *  OVS_KEY_ATTR_ENCAP                   0    --     4      4  (VLAN encapsulation)
- *  OVS_KEY_ATTR_ETHERTYPE               2     2     4      8  (inner VLAN ethertype)
- *  OVS_KEY_ATTR_IPV6                   40    --     4     44
- *  OVS_KEY_ATTR_ICMPV6                  2     2     4      8
- *  OVS_KEY_ATTR_ND                     28    --     4     32
- *  ----------------------------------------------------------
- *  total                                                 208
- */
-#define FLOW_BUFSIZE 208
-
 int ovs_flow_to_nlattrs(const struct sw_flow_key *, struct sk_buff *);
 int ovs_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_lenp,
                      const struct nlattr *);