Re: [PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[Feng Gao]

Sorry, I forget to modify the title.
I will sent another update.

On Sat, Aug 20, 2016 at 2:28 AM, Guillaume Nault  wrote:
> On Fri, Aug 19, 2016 at 05:55:26PM +0800, f...@ikuai8.com wrote:
>> From: Gao Feng 
>>
>> 1. Use PPP_ALLSTATIONS/PPP_UI instead of literal 0xff/0x03;
>> 2. Use one static const global fixed_ppphdr instead of two same
>> static variable ppph in two different functions;
>> 3. Use SEND_SHUTDOWN instead of literal 2;
>>
>> Signed-off-by: Gao Feng 
>> ---
>>  v1: Initial patch
>>
> v1 again?
>
> BTW, no need to number your patch for a single patch series.
> But you have to tell which tree is the series for.
>
> So instead of [PATCH v1 1/1], you should send [PATCH v2 net-next].

Re: [PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[David Miller]

From: f...@ikuai8.com
Date: Thu, 18 Aug 2016 15:05:19 +0800

> @@ -138,6 +138,8 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = {
>  
>  static const struct proto_ops pppol2tp_ops;
>  
> +static const unsigned char fixed_ppphdr[2] = {PPP_ALLSTATIONS, PPP_UI};
> +
>  /* Helpers to obtain tunnel/session contexts from sockets.
>   */
>  static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)

Same problem as the pptp patch, I'm not applying this.

Re: [PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[Guillaume Nault]

On Fri, Aug 19, 2016 at 05:55:26PM +0800, f...@ikuai8.com wrote:
> From: Gao Feng 
> 
> 1. Use PPP_ALLSTATIONS/PPP_UI instead of literal 0xff/0x03;
> 2. Use one static const global fixed_ppphdr instead of two same
> static variable ppph in two different functions;
> 3. Use SEND_SHUTDOWN instead of literal 2;
> 
> Signed-off-by: Gao Feng 
> ---
>  v1: Initial patch
> 
v1 again?

BTW, no need to number your patch for a single patch series.
But you have to tell which tree is the series for.

So instead of [PATCH v1 1/1], you should send [PATCH v2 net-next].

[PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[fgao]

From: Gao Feng 

1. Use PPP_ALLSTATIONS/PPP_UI instead of literal 0xff/0x03;
2. Use one static const global fixed_ppphdr instead of two same
static variable ppph in two different functions;
3. Use SEND_SHUTDOWN instead of literal 2;

Signed-off-by: Gao Feng 
---
 v1: Initial patch

 net/l2tp/l2tp_ppp.c | 28 ++--
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index d9560aa..0e69eb4 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -138,6 +138,8 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = {
 
 static const struct proto_ops pppol2tp_ops;
 
+static const unsigned char fixed_ppphdr[2] = {PPP_ALLSTATIONS, PPP_UI};
+
 /* Helpers to obtain tunnel/session contexts from sockets.
  */
 static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
@@ -174,11 +176,11 @@ static int pppol2tp_recv_payload_hook(struct sk_buff *skb)
 * Note that skb->data[] isn't dereferenced from a u16 ptr here since
 * the field may be unaligned.
 */
-   if (!pskb_may_pull(skb, 2))
+   if (!pskb_may_pull(skb, sizeof(fixed_ppphdr)))
return 1;
 
-   if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
-   skb_pull(skb, 2);
+   if ((PPP_ADDRESS(skb->data) == PPP_ALLSTATIONS) && 
(PPP_CONTROL(skb->data) == PPP_UI))
+   skb_pull(skb, sizeof(fixed_ppphdr));
 
return 0;
 }
@@ -282,7 +284,6 @@ static void pppol2tp_session_sock_put(struct l2tp_session 
*session)
 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
size_t total_len)
 {
-   static const unsigned char ppph[2] = { 0xff, 0x03 };
struct sock *sk = sock->sk;
struct sk_buff *skb;
int error;
@@ -312,7 +313,7 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
msghdr *m,
error = -ENOMEM;
skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
   uhlen + session->hdr_len +
-  sizeof(ppph) + total_len,
+  sizeof(fixed_ppphdr) + total_len,
   0, GFP_KERNEL);
if (!skb)
goto error_put_sess_tun;
@@ -325,9 +326,9 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
msghdr *m,
skb_reserve(skb, uhlen);
 
/* Add PPP header */
-   skb->data[0] = ppph[0];
-   skb->data[1] = ppph[1];
-   skb_put(skb, 2);
+   PPP_ADDRESS(skb->data) = fixed_ppphdr[0];
+   PPP_CONTROL(skb->data) = fixed_ppphdr[1];
+   skb_put(skb, sizeof(fixed_ppphdr));
 
/* Copy user data into skb */
error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
@@ -369,7 +370,6 @@ error:
  */
 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 {
-   static const u8 ppph[2] = { 0xff, 0x03 };
struct sock *sk = (struct sock *) chan->private;
struct sock *sk_tun;
struct l2tp_session *session;
@@ -398,14 +398,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct 
sk_buff *skb)
   sizeof(struct iphdr) + /* IP header */
   uhlen +  /* UDP header (if L2TP_ENCAPTYPE_UDP) */
   session->hdr_len +   /* L2TP header */
-  sizeof(ppph);/* PPP header */
+  sizeof(fixed_ppphdr); /* PPP header */
if (skb_cow_head(skb, headroom))
goto abort_put_sess_tun;
 
/* Setup PPP header */
-   __skb_push(skb, sizeof(ppph));
-   skb->data[0] = ppph[0];
-   skb->data[1] = ppph[1];
+   __skb_push(skb, sizeof(fixed_ppphdr));
+   skb->data[0] = fixed_ppphdr[0];
+   skb->data[1] = fixed_ppphdr[1];
 
local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
@@ -440,7 +440,7 @@ static void pppol2tp_session_close(struct l2tp_session 
*session)
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 
if (sock) {
-   inet_shutdown(sock, 2);
+   inet_shutdown(sock, SEND_SHUTDOWN);
/* Don't let the session go away before our socket does */
l2tp_session_inc_refcount(session);
}
-- 
1.9.1

Re: [PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[Guillaume Nault]

On Thu, Aug 18, 2016 at 03:05:19PM +0800, f...@ikuai8.com wrote:
> From: Gao Feng 
> 
> 1. Use PPP_ALLSTATIONS/PPP_UI instead of literal 0xff/0x03;
> 2. Use one static const global fixed_ppphdr instead of two same
> static variable ppph in two different functions;
> 3. Use SEND_SHUTDOWN instead of literal 2;
> 
> Signed-off-by: Gao Feng 
> ---
>  v1: Initial patch
No need to send 'v1' for the initial series.

> --- a/net/l2tp/l2tp_ppp.c
> +++ b/net/l2tp/l2tp_ppp.c
> @@ -138,6 +138,8 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = {
>  
>  static const struct proto_ops pppol2tp_ops;
>  
> +static const unsigned char fixed_ppphdr[2] = {PPP_ALLSTATIONS, PPP_UI};
> +
>  /* Helpers to obtain tunnel/session contexts from sockets.
>   */
>  static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
> @@ -174,11 +176,11 @@ static int pppol2tp_recv_payload_hook(struct sk_buff 
> *skb)
>* Note that skb->data[] isn't dereferenced from a u16 ptr here since
>* the field may be unaligned.
>*/
> - if (!pskb_may_pull(skb, 2))
> + if (!pskb_may_pull(skb, sizeof(fixed_ppphdr)))
>   return 1;
>  
> - if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
> - skb_pull(skb, 2);
> + if ((PPP_ADDRESS(skb->data) == PPP_ALLSTATIONS) && 
> (PPP_CONTROL(skb->data) == PPP_UI))
> + skb_pull(skb, sizeof(fixed_ppphdr));
>
Sorry, but I find the original code clearer. It's important to be
explicit about what's done with the sk_buff. Hiding skb->data[x] behind
macros certainly doesn't help.

Same thing for the use of sizeof(fixed_ppphdr) in pskb_may_pull(). The
size of fixed_ppphdr isn't used aftewards, so it's unclear why its size
was pulled. 2 was not a magic number here, it was directly related with
the operations done on the skb (i.e. accessing skb->data[0] and
skb->data[1]). So pskb_may_pull(skb, 2) makes perfect sense.

OTOH, replacing 0xff and 0x03 with PPP_ALLSTATIONS and PPP_UI is fine.

> @@ -312,7 +313,7 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
> msghdr *m,
>   error = -ENOMEM;
>   skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
>  uhlen + session->hdr_len +
> -sizeof(ppph) + total_len,
> +sizeof(fixed_ppphdr) + total_len,
>  0, GFP_KERNEL);
>   if (!skb)
>   goto error_put_sess_tun;
> @@ -325,9 +326,9 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
> msghdr *m,
>   skb_reserve(skb, uhlen);
>  
>   /* Add PPP header */
> - skb->data[0] = ppph[0];
> - skb->data[1] = ppph[1];
> - skb_put(skb, 2);
> + PPP_ADDRESS(skb->data) = fixed_ppphdr[0];
> + PPP_CONTROL(skb->data) = fixed_ppphdr[1];
> + skb_put(skb, sizeof(fixed_ppphdr));
>
Same here. What about
+ skb->data[0] = PPP_ALLSTATIONS;
+ skb->data[1] = PPP_UI;
+ skb_put(skb, 2);
and removing ppph entirely?

>   /* Copy user data into skb */
>   error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
> @@ -369,7 +370,6 @@ error:
>   */
>  static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
>  {
> - static const u8 ppph[2] = { 0xff, 0x03 };
>   struct sock *sk = (struct sock *) chan->private;
>   struct sock *sk_tun;
>   struct l2tp_session *session;
> @@ -398,14 +398,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, 
> struct sk_buff *skb)
>  sizeof(struct iphdr) + /* IP header */
>  uhlen +  /* UDP header (if L2TP_ENCAPTYPE_UDP) */
>  session->hdr_len +   /* L2TP header */
> -sizeof(ppph);/* PPP header */
> +sizeof(fixed_ppphdr); /* PPP header */
>   if (skb_cow_head(skb, headroom))
>   goto abort_put_sess_tun;
>  
>   /* Setup PPP header */
> - __skb_push(skb, sizeof(ppph));
> - skb->data[0] = ppph[0];
> - skb->data[1] = ppph[1];
> + __skb_push(skb, sizeof(fixed_ppphdr));
> + skb->data[0] = fixed_ppphdr[0];
> + skb->data[1] = fixed_ppphdr[1];
> 
Same as for pppol2tp_sendmsg().

> @@ -440,7 +440,7 @@ static void pppol2tp_session_close(struct l2tp_session 
> *session)
>   BUG_ON(session->magic != L2TP_SESSION_MAGIC);
>  
>   if (sock) {
> - inet_shutdown(sock, 2);
> + inet_shutdown(sock, SEND_SHUTDOWN);
> 
Ok.

Re: [PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[Feng Gao]

On Fri, Aug 19, 2016 at 2:41 AM, Guillaume Nault  wrote:
> On Thu, Aug 18, 2016 at 03:05:19PM +0800, f...@ikuai8.com wrote:
>> From: Gao Feng 
>>
>> 1. Use PPP_ALLSTATIONS/PPP_UI instead of literal 0xff/0x03;
>> 2. Use one static const global fixed_ppphdr instead of two same
>> static variable ppph in two different functions;
>> 3. Use SEND_SHUTDOWN instead of literal 2;
>>
>> Signed-off-by: Gao Feng 
>> ---
>>  v1: Initial patch
> No need to send 'v1' for the initial series.

OK, I get it.

>
>> --- a/net/l2tp/l2tp_ppp.c
>> +++ b/net/l2tp/l2tp_ppp.c
>> @@ -138,6 +138,8 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = {
>>
>>  static const struct proto_ops pppol2tp_ops;
>>
>> +static const unsigned char fixed_ppphdr[2] = {PPP_ALLSTATIONS, PPP_UI};
>> +
>>  /* Helpers to obtain tunnel/session contexts from sockets.
>>   */
>>  static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
>> @@ -174,11 +176,11 @@ static int pppol2tp_recv_payload_hook(struct sk_buff 
>> *skb)
>>* Note that skb->data[] isn't dereferenced from a u16 ptr here since
>>* the field may be unaligned.
>>*/
>> - if (!pskb_may_pull(skb, 2))
>> + if (!pskb_may_pull(skb, sizeof(fixed_ppphdr)))
>>   return 1;
>>
>> - if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
>> - skb_pull(skb, 2);
>> + if ((PPP_ADDRESS(skb->data) == PPP_ALLSTATIONS) && 
>> (PPP_CONTROL(skb->data) == PPP_UI))
>> + skb_pull(skb, sizeof(fixed_ppphdr));
>>
> Sorry, but I find the original code clearer. It's important to be
> explicit about what's done with the sk_buff. Hiding skb->data[x] behind
> macros certainly doesn't help.
>
> Same thing for the use of sizeof(fixed_ppphdr) in pskb_may_pull(). The
> size of fixed_ppphdr isn't used aftewards, so it's unclear why its size
> was pulled. 2 was not a magic number here, it was directly related with
> the operations done on the skb (i.e. accessing skb->data[0] and
> skb->data[1]). So pskb_may_pull(skb, 2) makes perfect sense.

Agree now because of detail explanation.
Thanks.

>
> OTOH, replacing 0xff and 0x03 with PPP_ALLSTATIONS and PPP_UI is fine.

OK. get it.

>
>> @@ -312,7 +313,7 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
>> msghdr *m,
>>   error = -ENOMEM;
>>   skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
>>  uhlen + session->hdr_len +
>> -sizeof(ppph) + total_len,
>> +sizeof(fixed_ppphdr) + total_len,
>>  0, GFP_KERNEL);
>>   if (!skb)
>>   goto error_put_sess_tun;
>> @@ -325,9 +326,9 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
>> msghdr *m,
>>   skb_reserve(skb, uhlen);
>>
>>   /* Add PPP header */
>> - skb->data[0] = ppph[0];
>> - skb->data[1] = ppph[1];
>> - skb_put(skb, 2);
>> + PPP_ADDRESS(skb->data) = fixed_ppphdr[0];
>> + PPP_CONTROL(skb->data) = fixed_ppphdr[1];
>> + skb_put(skb, sizeof(fixed_ppphdr));
>>
> Same here. What about
> + skb->data[0] = PPP_ALLSTATIONS;
> + skb->data[1] = PPP_UI;
> + skb_put(skb, 2);
> and removing ppph entirely?

Agree with you.

>
>>   /* Copy user data into skb */
>>   error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
>> @@ -369,7 +370,6 @@ error:
>>   */
>>  static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
>>  {
>> - static const u8 ppph[2] = { 0xff, 0x03 };
>>   struct sock *sk = (struct sock *) chan->private;
>>   struct sock *sk_tun;
>>   struct l2tp_session *session;
>> @@ -398,14 +398,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, 
>> struct sk_buff *skb)
>>  sizeof(struct iphdr) + /* IP header */
>>  uhlen +  /* UDP header (if L2TP_ENCAPTYPE_UDP) 
>> */
>>  session->hdr_len +   /* L2TP header */
>> -sizeof(ppph);/* PPP header */
>> +sizeof(fixed_ppphdr); /* PPP header */
>>   if (skb_cow_head(skb, headroom))
>>   goto abort_put_sess_tun;
>>
>>   /* Setup PPP header */
>> - __skb_push(skb, sizeof(ppph));
>> - skb->data[0] = ppph[0];
>> - skb->data[1] = ppph[1];
>> + __skb_push(skb, sizeof(fixed_ppphdr));
>> + skb->data[0] = fixed_ppphdr[0];
>> + skb->data[1] = fixed_ppphdr[1];
>>
> Same as for pppol2tp_sendmsg().
>
>> @@ -440,7 +440,7 @@ static void pppol2tp_session_close(struct l2tp_session 
>> *session)
>>   BUG_ON(session->magic != L2TP_SESSION_MAGIC);
>>
>>   if (sock) {
>> - inet_shutdown(sock, 2);
>> + inet_shutdown(sock, SEND_SHUTDOWN);
>>
> Ok.

Regards
Feng

[PATCH v1 1/1] l2tp: Use existing macros instead of literal number

[fgao]

From: Gao Feng 

1. Use PPP_ALLSTATIONS/PPP_UI instead of literal 0xff/0x03;
2. Use one static const global fixed_ppphdr instead of two same
static variable ppph in two different functions;
3. Use SEND_SHUTDOWN instead of literal 2;

Signed-off-by: Gao Feng 
---
 v1: Initial patch

 net/l2tp/l2tp_ppp.c | 28 ++--
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index d9560aa..0e69eb4 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -138,6 +138,8 @@ static const struct ppp_channel_ops pppol2tp_chan_ops = {
 
 static const struct proto_ops pppol2tp_ops;
 
+static const unsigned char fixed_ppphdr[2] = {PPP_ALLSTATIONS, PPP_UI};
+
 /* Helpers to obtain tunnel/session contexts from sockets.
  */
 static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
@@ -174,11 +176,11 @@ static int pppol2tp_recv_payload_hook(struct sk_buff *skb)
 * Note that skb->data[] isn't dereferenced from a u16 ptr here since
 * the field may be unaligned.
 */
-   if (!pskb_may_pull(skb, 2))
+   if (!pskb_may_pull(skb, sizeof(fixed_ppphdr)))
return 1;
 
-   if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03))
-   skb_pull(skb, 2);
+   if ((PPP_ADDRESS(skb->data) == PPP_ALLSTATIONS) && 
(PPP_CONTROL(skb->data) == PPP_UI))
+   skb_pull(skb, sizeof(fixed_ppphdr));
 
return 0;
 }
@@ -282,7 +284,6 @@ static void pppol2tp_session_sock_put(struct l2tp_session 
*session)
 static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
size_t total_len)
 {
-   static const unsigned char ppph[2] = { 0xff, 0x03 };
struct sock *sk = sock->sk;
struct sk_buff *skb;
int error;
@@ -312,7 +313,7 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
msghdr *m,
error = -ENOMEM;
skb = sock_wmalloc(sk, NET_SKB_PAD + sizeof(struct iphdr) +
   uhlen + session->hdr_len +
-  sizeof(ppph) + total_len,
+  sizeof(fixed_ppphdr) + total_len,
   0, GFP_KERNEL);
if (!skb)
goto error_put_sess_tun;
@@ -325,9 +326,9 @@ static int pppol2tp_sendmsg(struct socket *sock, struct 
msghdr *m,
skb_reserve(skb, uhlen);
 
/* Add PPP header */
-   skb->data[0] = ppph[0];
-   skb->data[1] = ppph[1];
-   skb_put(skb, 2);
+   PPP_ADDRESS(skb->data) = fixed_ppphdr[0];
+   PPP_CONTROL(skb->data) = fixed_ppphdr[1];
+   skb_put(skb, sizeof(fixed_ppphdr));
 
/* Copy user data into skb */
error = memcpy_from_msg(skb_put(skb, total_len), m, total_len);
@@ -369,7 +370,6 @@ error:
  */
 static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 {
-   static const u8 ppph[2] = { 0xff, 0x03 };
struct sock *sk = (struct sock *) chan->private;
struct sock *sk_tun;
struct l2tp_session *session;
@@ -398,14 +398,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct 
sk_buff *skb)
   sizeof(struct iphdr) + /* IP header */
   uhlen +  /* UDP header (if L2TP_ENCAPTYPE_UDP) */
   session->hdr_len +   /* L2TP header */
-  sizeof(ppph);/* PPP header */
+  sizeof(fixed_ppphdr); /* PPP header */
if (skb_cow_head(skb, headroom))
goto abort_put_sess_tun;
 
/* Setup PPP header */
-   __skb_push(skb, sizeof(ppph));
-   skb->data[0] = ppph[0];
-   skb->data[1] = ppph[1];
+   __skb_push(skb, sizeof(fixed_ppphdr));
+   skb->data[0] = fixed_ppphdr[0];
+   skb->data[1] = fixed_ppphdr[1];
 
local_bh_disable();
l2tp_xmit_skb(session, skb, session->hdr_len);
@@ -440,7 +440,7 @@ static void pppol2tp_session_close(struct l2tp_session 
*session)
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
 
if (sock) {
-   inet_shutdown(sock, 2);
+   inet_shutdown(sock, SEND_SHUTDOWN);
/* Don't let the session go away before our socket does */
l2tp_session_inc_refcount(session);
}
-- 
1.9.1