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datapath: Refine Netlink message size calculation and kill FLOW_BUFSIZE
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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 <[email protected]>
Signed-off-by: Jesse Gross <[email protected]>
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@tgraf @jessegross
tgraf authored and jessegross committed Mar 30, 2013
1 parent bf3d6fc commit 0afa237
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Showing 2 changed files with 60 additions and 53 deletions.
84 changes: 60 additions & 24 deletions datapath/datapath.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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)) {
Expand All @@ -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;
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -1133,25 +1173,11 @@ static int ovs_flow_cmd_fill_info(struct sw_flow *flow, struct datapath *dp,
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,
Expand Down Expand Up @@ -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)
{
Expand Down Expand Up @@ -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);

Expand Down
29 changes: 0 additions & 29 deletions datapath/flow.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 *);
Expand Down

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