[ovs-dev] [PATCH net-next v11] openvswitch: enable NSH support
Yang, Yi
yi.y.yang at intel.com
Mon Oct 9 08:05:29 UTC 2017
On Tue, Oct 03, 2017 at 03:13:08AM +0800, Jiri Benc wrote:
> On Fri, 29 Sep 2017 15:03:30 +0800, Yi Yang wrote:
> > --- a/include/net/nsh.h
> > +++ b/include/net/nsh.h
> > @@ -304,4 +304,7 @@ static inline void nsh_set_flags_ttl_len(struct nshhdr *nsh, u8 flags,
> > NSH_FLAGS_MASK | NSH_TTL_MASK | NSH_LEN_MASK);
> > }
> >
> > +int skb_push_nsh(struct sk_buff *skb, const struct nshhdr *nh);
>
> [...]
> > +int skb_push_nsh(struct sk_buff *skb, const struct nshhdr *src_nsh_hdr)
>
> This is minor but since this patch will need a respin anyway, please
> name the variables in the forward declaration and here the same.
Sorry for late reply, I was taking vacation from Oct. 1 to Oct. 8. I will
change "nh" and "src_nsh_hdr" to "pushed_nsh" because there is
another nh inside of skb_push_nsh.
>
> > +int skb_pop_nsh(struct sk_buff *skb)
> > +{
> > + int err;
> > + struct nshhdr *nsh_hdr = (struct nshhdr *)(skb->data);
>
> Bad name of the variable, clashes with the nsh_hdr function. I pointed
> that out already.
Sorry for missing this, I just did change in one .c file, forgot to do
the same thing in other .c files.
>
> > + size_t length;
> > + __be16 inner_proto;
> > +
> > + err = skb_ensure_writable(skb, skb_network_offset(skb) +
> > + sizeof(struct nshhdr));
>
> You assume that the skb starts at the NSH header, thus the
> skb_network_offset is completely unnecessary and introduces just
> another assumption on the caller. Also, the sizeof(struct nshhdr) is
> wrong: there's no guarantee that the header is not smaller or larger
> than that.
>
> More importantly though, why do you need skb_ensure_writable? You don't
> write into the header. pkskb_may_pull is enough.
>
> if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN))
> return -ENOMEM;
> length = nsh_hdr_len(nsh_hdr);
> if (!pskb_may_pull(skb, length))
> return -ENOMEM;
>
Thank you for pointing out this, your version is the best one.
> > +static int set_nsh(struct sk_buff *skb, struct sw_flow_key *flow_key,
> > + const struct nlattr *a)
> > +{
> > + struct nshhdr *nh;
> > + int err;
> > + u8 flags;
> > + u8 ttl;
> > + int i;
> > +
> > + struct ovs_key_nsh key;
> > + struct ovs_key_nsh mask;
> > +
> > + err = nsh_key_from_nlattr(a, &key, &mask);
> > + if (err)
> > + return err;
> > +
> > + err = skb_ensure_writable(skb, skb_network_offset(skb) +
> > + sizeof(struct nshhdr));
>
> I missed this before: this is wrong, too. You need to use the real
> header size, not sizeof(struct nshhdr). It should be computable from
> the flow key.
It will be better to use code you provided above.
>
> > + case OVS_ACTION_ATTR_PUSH_NSH: {
> > + u8 buffer[NSH_HDR_MAX_LEN];
> > + struct nshhdr *nh = (struct nshhdr *)buffer;
> > +
> > + nsh_hdr_from_nlattr(nla_data(a), nh,
> > + NSH_HDR_MAX_LEN);
> > + err = push_nsh(skb, key, (const struct nshhdr *)nh);
>
> Is the cast to const really needed? It looks suspicious. If you added it
> because a compiler complained, it's even more suspicious.
You're right, it is ok after I remove "(const struct nshhdr *)".
>
> > +static int parse_nsh(struct sk_buff *skb, struct sw_flow_key *key)
> > +{
> > + struct nshhdr *nh;
> > + unsigned int nh_ofs = skb_network_offset(skb);
> > + u8 version, length;
> > + int err;
> > +
> > + err = check_header(skb, nh_ofs + NSH_BASE_HDR_LEN);
> > + if (unlikely(err))
> > + return err;
> > +
> > + nh = nsh_hdr(skb);
> > + version = nsh_get_ver(nh);
> > + length = nsh_hdr_len(nh);
> > +
> > + if (version != 0)
> > + return -EINVAL;
> > +
> > + err = check_header(skb, nh_ofs + length);
> > + if (unlikely(err))
> > + return err;
> > +
> > + nh = (struct nshhdr *)skb_network_header(skb);
>
> I really really really hate this. This is the third time I'm telling
> you to use the nsh_hdr function. Every time, you change only part of
> the places. And this one I even explicitly pointed out in the previous
> review.
>
> I'm not supposed to look at my previous review to verify that you
> addressed everything. That's your responsibility. Yet I need to do it
> because every time, some of my comments remain unaddressed.
Sorry, it is a missing change, accumulated comments overwhelmed this.
>
> > +int nsh_hdr_from_nlattr(const struct nlattr *attr,
> > + struct nshhdr *nh, size_t size)
> > +{
> > + struct nlattr *a;
> > + int rem;
> > + u8 flags = 0;
> > + u8 ttl = 0;
> > + int mdlen = 0;
> > +
> > + /* validate_nsh has check this, so we needn't do duplicate check here
> > + */
> > + nla_for_each_nested(a, attr, rem) {
> > + int type = nla_type(a);
> > +
> > + switch (type) {
> > + case OVS_NSH_KEY_ATTR_BASE: {
> > + const struct ovs_nsh_key_base *base = nla_data(a);
> > +
> > + flags = base->flags;
> > + ttl = base->ttl;
> > + nh->np = base->np;
> > + nh->mdtype = base->mdtype;
> > + nh->path_hdr = base->path_hdr;
> > + break;
> > + }
> > + case OVS_NSH_KEY_ATTR_MD1: {
> > + const struct ovs_nsh_key_md1 *md1 = nla_data(a);
> > +
> > + mdlen = nla_len(a);
> > + memcpy(&nh->md1, md1, mdlen);
> > + break;
>
> Looks better. Why not simplify it even more?
>
> case OVS_NSH_KEY_ATTR_MD1:
> mdlen = nla_len(a);
> memcpy(&nh->md1, nla_data(a), mdlen);
> break;
>
> It's still perfectly readable this way and there's no need for the
> braces.
>
> > + }
> > + case OVS_NSH_KEY_ATTR_MD2: {
> > + const struct u8 *md2 = nla_data(a);
> > +
> > + mdlen = nla_len(a);
> > + memcpy(&nh->md2, md2, mdlen);
>
> And here, too.
Yes, the code you provided is better.
>
> > +int nsh_key_from_nlattr(const struct nlattr *attr,
> > + struct ovs_key_nsh *nsh, struct ovs_key_nsh *nsh_mask)
> > +{
> > + struct nlattr *a;
> > + int rem;
> > +
> > + /* validate_nsh has check this, so we needn't do duplicate check here
> > + */
> > + nla_for_each_nested(a, attr, rem) {
> > + int type = nla_type(a);
> > +
> > + switch (type) {
> > + case OVS_NSH_KEY_ATTR_BASE: {
> > + const struct ovs_nsh_key_base *base = nla_data(a);
> > + const struct ovs_nsh_key_base *base_mask = base + 1;
> > +
> > + nsh->base = *base;
> > + nsh_mask->base = *base_mask;
> > + break;
> > + }
> > + case OVS_NSH_KEY_ATTR_MD1: {
> > + const struct ovs_nsh_key_md1 *md1 =
> > + (struct ovs_nsh_key_md1 *)nla_data(a);
>
> I'm speechless.
>
> Yes, I don't like the line above. For a reason that I already pointed
> out.
>
> I expected more of this version.
Sorry, these are also missing changes, I remember I did global change
about this comment, it is my bad.
Here is incremental patch against v11, I'll send out v12 if you haven't
more comments about this.
diff -u b/include/net/nsh.h b/include/net/nsh.h
--- b/include/net/nsh.h
+++ b/include/net/nsh.h
@@ -304,7 +304,7 @@
NSH_FLAGS_MASK | NSH_TTL_MASK | NSH_LEN_MASK);
}
-int skb_push_nsh(struct sk_buff *skb, const struct nshhdr *nh);
+int skb_push_nsh(struct sk_buff *skb, const struct nshhdr *pushed_nh);
int skb_pop_nsh(struct sk_buff *skb);
#endif /* __NET_NSH_H */
diff -u b/net/nsh/nsh.c b/net/nsh/nsh.c
--- b/net/nsh/nsh.c
+++ b/net/nsh/nsh.c
@@ -14,10 +14,10 @@
#include <net/nsh.h>
#include <net/tun_proto.h>
-int skb_push_nsh(struct sk_buff *skb, const struct nshhdr *src_nsh_hdr)
+int skb_push_nsh(struct sk_buff *skb, const struct nshhdr *pushed_nh)
{
- struct nshhdr *nsh_hdr;
- size_t length = nsh_hdr_len(src_nsh_hdr);
+ struct nshhdr *nh;
+ size_t length = nsh_hdr_len(pushed_nh);
u8 next_proto;
if (skb->mac_len) {
@@ -33,9 +33,9 @@
return -ENOMEM;
skb_push(skb, length);
- nsh_hdr = (struct nshhdr *)(skb->data);
- memcpy(nsh_hdr, src_nsh_hdr, length);
- nsh_hdr->np = next_proto;
+ nh = (struct nshhdr *)(skb->data);
+ memcpy(nh, pushed_nh, length);
+ nh->np = next_proto;
skb->protocol = htons(ETH_P_NSH);
skb_reset_mac_header(skb);
@@ -48,21 +48,23 @@
int skb_pop_nsh(struct sk_buff *skb)
{
- int err;
- struct nshhdr *nsh_hdr = (struct nshhdr *)(skb->data);
+ struct nshhdr *nh;
size_t length;
__be16 inner_proto;
- err = skb_ensure_writable(skb, skb_network_offset(skb) +
- sizeof(struct nshhdr));
- if (unlikely(err))
- return err;
+ if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN))
+ return -ENOMEM;
+ nh = (struct nshhdr *)(skb->data);
+ length = nsh_hdr_len(nh);
+ if (!pskb_may_pull(skb, length))
+ return -ENOMEM;
- inner_proto = tun_p_to_eth_p(nsh_hdr->np);
+ nh = (struct nshhdr *)(skb->data);
+ inner_proto = tun_p_to_eth_p(nh->np);
if (!inner_proto)
return -EAFNOSUPPORT;
- length = nsh_hdr_len(nsh_hdr);
+ length = nsh_hdr_len(nh);
skb_pull(skb, length);
skb_reset_mac_header(skb);
skb_reset_network_header(skb);
diff -u b/net/openvswitch/actions.c b/net/openvswitch/actions.c
--- b/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -644,6 +644,7 @@
const struct nlattr *a)
{
struct nshhdr *nh;
+ size_t length;
int err;
u8 flags;
u8 ttl;
@@ -656,13 +657,22 @@
if (err)
return err;
+ /* Make sure the NSH base header is there */
err = skb_ensure_writable(skb, skb_network_offset(skb) +
- sizeof(struct nshhdr));
+ NSH_BASE_HDR_LEN);
if (unlikely(err))
return err;
nh = nsh_hdr(skb);
+ length = nsh_hdr_len(nh);
+ /* Make sure the whole NSH header is there */
+ err = skb_ensure_writable(skb, skb_network_offset(skb) +
+ length);
+ if (unlikely(err))
+ return err;
+
+ nh = nsh_hdr(skb);
flags = nsh_get_flags(nh);
flags = OVS_MASKED(flags, key.base.flags, mask.base.flags);
flow_key->nsh.base.flags = flags;
@@ -1312,7 +1322,7 @@
nsh_hdr_from_nlattr(nla_data(a), nh,
NSH_HDR_MAX_LEN);
- err = push_nsh(skb, key, (const struct nshhdr *)nh);
+ err = push_nsh(skb, key, nh);
break;
}
diff -u b/net/openvswitch/flow.c b/net/openvswitch/flow.c
--- b/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -513,7 +513,7 @@
if (unlikely(err))
return err;
- nh = (struct nshhdr *)skb_network_header(skb);
+ nh = nsh_hdr(skb);
key->nsh.base.flags = nsh_get_flags(nh);
key->nsh.base.ttl = nsh_get_ttl(nh);
key->nsh.base.mdtype = nh->mdtype;
diff -u b/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
--- b/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -1233,20 +1233,16 @@
nh->path_hdr = base->path_hdr;
break;
}
- case OVS_NSH_KEY_ATTR_MD1: {
- const struct ovs_nsh_key_md1 *md1 = nla_data(a);
-
+ case OVS_NSH_KEY_ATTR_MD1:
mdlen = nla_len(a);
- memcpy(&nh->md1, md1, mdlen);
+ memcpy(&nh->md1, nla_data(a), mdlen);
break;
- }
- case OVS_NSH_KEY_ATTR_MD2: {
- const struct u8 *md2 = nla_data(a);
+ case OVS_NSH_KEY_ATTR_MD2:
mdlen = nla_len(a);
- memcpy(&nh->md2, md2, mdlen);
+ memcpy(&nh->md2, nla_data(a), mdlen);
break;
- }
+
default:
return -EINVAL;
}
@@ -1280,8 +1276,7 @@
break;
}
case OVS_NSH_KEY_ATTR_MD1: {
- const struct ovs_nsh_key_md1 *md1 =
- (struct ovs_nsh_key_md1 *)nla_data(a);
+ const struct ovs_nsh_key_md1 *md1 = nla_data(a);
const struct ovs_nsh_key_md1 *md1_mask = md1 + 1;
memcpy(nsh->context, md1->context, sizeof(*md1));
@@ -1339,8 +1334,7 @@
switch (type) {
case OVS_NSH_KEY_ATTR_BASE: {
- const struct ovs_nsh_key_base *base =
- (struct ovs_nsh_key_base *)nla_data(a);
+ const struct ovs_nsh_key_base *base = nla_data(a);
has_base = true;
mdtype = base->mdtype;
@@ -1357,8 +1351,7 @@
break;
}
case OVS_NSH_KEY_ATTR_MD1: {
- const struct ovs_nsh_key_md1 *md1 =
- (struct ovs_nsh_key_md1 *)nla_data(a);
+ const struct ovs_nsh_key_md1 *md1 = nla_data(a);
has_md1 = true;
for (i = 0; i < NSH_MD1_CONTEXT_SIZE; i++)
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