[ovs-dev] [PATCH] datapath: Avoid NULL mask check while building mask

Pravin Shelar pshelar at nicira.com
Fri Aug 8 22:58:02 UTC 2014


On Fri, Aug 8, 2014 at 1:56 PM, Andy Zhou <azhou at nicira.com> wrote:
> I agree with Daniele's comments.
>
> Acked-by: Andy Zhou <azhou at nicira.com>
>
Thanks I pushed patch to master.

> mask_set_nlattr() seems to have a single user. may be we cna remove
> this function and
> call set_nlattr() directly?
>
> Not part of this patch, but set_nlattr() does not look correct in
> handling nested attributes.
>
can you elaborate on that? It should handle ovs key attributes.

>
> On Fri, Aug 8, 2014 at 9:25 AM, Daniele Di Proietto
> <ddiproietto at vmware.com> wrote:
>> Hi Pravin,
>>
>> couple of comments:
>>
>> - I would remove also the check for match->mask in update_range__().
>> - I think braces are not necessary for if/else statements in the macros.
>>
>> Of course I would wait for review by Jesse or Andy, but other than that,
>> LGTM.
>>
>> Acked-by: Daniele Di Proietto <ddiproietto at vmware.com>
>>
>>
>> On 8/7/14, 9:26 PM, "Pravin B Shelar" <pshelar at nicira.com> wrote:
>>
>>>OVS does mask validation even if it does not need to convert
>>>netlink mask attributes to mask structure.  ovs_nla_get_match()
>>>caller can pass NULL mask structure pointer if the caller does
>>>not need mask.  Therefore NULL check is required in SW_FLOW_KEY*
>>>macros.  Following patch does not convert mask netlink attributes
>>>if mask pointer is NULL, so we do not need these checks in
>>>SW_FLOW_KEY* macro.
>>>
>>>Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
>>>---
>>> datapath/flow_netlink.c | 74
>>>++++++++++++++++++++++++++-----------------------
>>> 1 file changed, 39 insertions(+), 35 deletions(-)
>>>
>>>diff --git a/datapath/flow_netlink.c b/datapath/flow_netlink.c
>>>index 75172de..63ab7a6 100644
>>>--- a/datapath/flow_netlink.c
>>>+++ b/datapath/flow_netlink.c
>>>@@ -84,8 +84,7 @@ static void update_range__(struct sw_flow_match *match,
>>>               update_range__(match, offsetof(struct sw_flow_key, field),  \
>>>                                    sizeof((match)->key->field), is_mask); \
>>>               if (is_mask) {                                              \
>>>-                      if ((match)->mask)                                  \
>>>-                              (match)->mask->key.field = value;           \
>>>+                      (match)->mask->key.field = value;                   \
>>>               } else {                                                    \
>>>                       (match)->key->field = value;                        \
>>>               }                                                           \
>>>@@ -95,10 +94,9 @@ static void update_range__(struct sw_flow_match *match,
>>>       do { \
>>>               update_range__(match, offset, len, is_mask);                \
>>>               if (is_mask) {                                              \
>>>-                      if ((match)->mask)                                  \
>>>-                              memcpy((u8 *)&(match)->mask->key + offset, value_p, len);\
>>>+                      memcpy((u8 *)&(match)->mask->key + offset, value_p, len);\
>>>               } else {                                                    \
>>>-                      memcpy((u8 *)(match)->key + offset, value_p, len);         \
>>>+                      memcpy((u8 *)(match)->key + offset, value_p, len);  \
>>>               }                                                           \
>>>       } while (0)
>>>
>>>@@ -111,9 +109,8 @@ static void update_range__(struct sw_flow_match
>>>*match,
>>>               update_range__(match, offsetof(struct sw_flow_key, field),  \
>>>                                    sizeof((match)->key->field), is_mask); \
>>>               if (is_mask) {                                              \
>>>-                      if ((match)->mask)                                  \
>>>-                              memset((u8 *)&(match)->mask->key.field, value,\
>>>-                                     sizeof((match)->mask->key.field));   \
>>>+                      memset((u8 *)&(match)->mask->key.field, value,\
>>>+                             sizeof((match)->mask->key.field));   \
>>>               } else {                                                    \
>>>                       memset((u8 *)&(match)->key->field, value,           \
>>>                              sizeof((match)->key->field));                \
>>>@@ -633,8 +630,7 @@ static int ovs_key_from_nlattrs(struct sw_flow_match
>>>*match, u64 attrs,
>>>
>>>               SW_FLOW_KEY_PUT(match, eth.tci, tci, is_mask);
>>>               attrs &= ~(1ULL << OVS_KEY_ATTR_VLAN);
>>>-      } else if (!is_mask)
>>>-              SW_FLOW_KEY_PUT(match, eth.tci, htons(0xffff), true);
>>>+      }
>>>
>>>       if (attrs & (1ULL << OVS_KEY_ATTR_ETHERTYPE)) {
>>>               __be16 eth_type;
>>>@@ -859,8 +855,8 @@ static void mask_set_nlattr(struct nlattr *attr, u8
>>>val)
>>>  * attribute specifies the mask field of the wildcarded flow.
>>>  */
>>> int ovs_nla_get_match(struct sw_flow_match *match,
>>>-                    const struct nlattr *key,
>>>-                    const struct nlattr *mask)
>>>+                    const struct nlattr *nla_key,
>>>+                    const struct nlattr *nla_mask)
>>> {
>>>       const struct nlattr *a[OVS_KEY_ATTR_MAX + 1];
>>>       const struct nlattr *encap;
>>>@@ -870,7 +866,7 @@ int ovs_nla_get_match(struct sw_flow_match *match,
>>>       bool encap_valid = false;
>>>       int err;
>>>
>>>-      err = parse_flow_nlattrs(key, a, &key_attrs);
>>>+      err = parse_flow_nlattrs(nla_key, a, &key_attrs);
>>>       if (err)
>>>               return err;
>>>
>>>@@ -911,35 +907,43 @@ int ovs_nla_get_match(struct sw_flow_match *match,
>>>       if (err)
>>>               return err;
>>>
>>>-      if (match->mask && !mask) {
>>>-              /* Create an exact match mask. We need to set to 0xff all the
>>>-               * 'match->mask' fields that have been touched in 'match->key'.
>>>-               * We cannot simply memset 'match->mask', because padding bytes
>>>-               * and fields not specified in 'match->key' should be left to 0.
>>>-               * Instead, we use a stream of netlink attributes, copied from
>>>-               * 'key' and set to 0xff: ovs_key_from_nlattrs() will take care
>>>-               * of filling 'match->mask' appropriately.
>>>-               */
>>>-              newmask = kmemdup(key, nla_total_size(nla_len(key)),
>>>-                                GFP_KERNEL);
>>>-              if (!newmask)
>>>-                      return -ENOMEM;
>>>+      if (match->mask) {
>>>+
>>>+              if (!nla_mask) {
>>>+                      /* Create an exact match mask. We need to set to 0xff
>>>+                       * all the 'match->mask' fields that have been touched
>>>+                       * in 'match->key'. We cannot simply memset
>>>+                       * 'match->mask', because padding bytes and fields not
>>>+                       * specified in 'match->key' should be left to 0.
>>>+                       * Instead, we use a stream of netlink attributes,
>>>+                       * copied from 'key' and set to 0xff: ovs_key_from_nlattrs()
>>>+                       * will take care of filling 'match->mask' appropriately.
>>>+                       */
>>>+                      newmask = kmemdup(nla_key,
>>>+                                        nla_total_size(nla_len(nla_key)),
>>>+                                        GFP_KERNEL);
>>>+                      if (!newmask)
>>>+                              return -ENOMEM;
>>>
>>>-              mask_set_nlattr(newmask, 0xff);
>>>+                      mask_set_nlattr(newmask, 0xff);
>>>
>>>-              /* The userspace does not send tunnel attributes that are 0,
>>>-               * but we should not wildcard them nonetheless. */
>>>-              if (match->key->tun_key.ipv4_dst)
>>>-                      SW_FLOW_KEY_MEMSET_FIELD(match, tun_key, 0xff, true);
>>>+                      /* The userspace does not send tunnel attributes that
>>>+                       * are 0, but we should not wildcard them nonetheless.
>>>+                       */
>>>+                      if (match->key->tun_key.ipv4_dst)
>>>+                              SW_FLOW_KEY_MEMSET_FIELD(match, tun_key,
>>>+                                                       0xff, true);
>>>
>>>-              mask = newmask;
>>>-      }
>>>+                      nla_mask = newmask;
>>>+              }
>>>
>>>-      if (mask) {
>>>-              err = parse_flow_mask_nlattrs(mask, a, &mask_attrs);
>>>+              err = parse_flow_mask_nlattrs(nla_mask, a, &mask_attrs);
>>>               if (err)
>>>                       goto free_newmask;
>>>
>>>+              /* Always match on tci. */
>>>+              SW_FLOW_KEY_PUT(match, eth.tci, htons(0xffff), true);
>>>+
>>>               if (mask_attrs & 1ULL << OVS_KEY_ATTR_ENCAP) {
>>>                       __be16 eth_type = 0;
>>>                       __be16 tci = 0;
>>>--
>>>1.9.3
>>>
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>>
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