[nf,v2] netfilter: flowtable: add nf_flowtable_time_stamp

This patch adds nf_flowtable_time_stamp and updates the existing code to
use it.

This patch is also implicitly fixing up hardware statistic fetching via
nf_flow_offload_stats() where casting to u32 is missing. Use
nf_flow_timeout_delta() to fix this.

Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v2: use nf_flow_timeout_delta()

 include/net/netfilter/nf_flow_table.h | 6 ++++++
 net/netfilter/nf_flow_table_core.c    | 7 +------
 net/netfilter/nf_flow_table_ip.c      | 4 ++--
 net/netfilter/nf_flow_table_offload.c | 4 ++--
 4 files changed, 11 insertions(+), 10 deletions(-)

On 1/6/2020 3:10 AM, Pablo Neira Ayuso wrote:
> This patch adds nf_flowtable_time_stamp and updates the existing code to
> use it.
>
> This patch is also implicitly fixing up hardware statistic fetching via
> nf_flow_offload_stats() where casting to u32 is missing. Use
> nf_flow_timeout_delta() to fix this.
>
> Fixes: c29f74e0df7a ("netfilter: nf_flow_table: hardware offload support")
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
> v2: use nf_flow_timeout_delta()
>
>  include/net/netfilter/nf_flow_table.h | 6 ++++++
>  net/netfilter/nf_flow_table_core.c    | 7 +------
>  net/netfilter/nf_flow_table_ip.c      | 4 ++--
>  net/netfilter/nf_flow_table_offload.c | 4 ++--
>  4 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/include/net/netfilter/nf_flow_table.h b/include/net/netfilter/nf_flow_table.h
> index f0897b3c97fb..03cc74bb2598 100644
> --- a/include/net/netfilter/nf_flow_table.h
> +++ b/include/net/netfilter/nf_flow_table.h
> @@ -106,6 +106,12 @@ struct flow_offload {
>  };
>  
>  #define NF_FLOW_TIMEOUT (30 * HZ)
> +#define nf_flowtable_time_stamp	(u32)jiffies
> +
> +static inline __s32 nf_flow_timeout_delta(unsigned int timeout)
> +{
> +	return (__s32)(timeout - (u32)jiffies);
Maybe this also can replace (u32)jiffies to nf_flowtable_time_stamp.
> +}
>  
>  struct nf_flow_route {
>  	struct {
> diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
> index 9889d52eda82..e33a73cb1f42 100644
> --- a/net/netfilter/nf_flow_table_core.c
> +++ b/net/netfilter/nf_flow_table_core.c
> @@ -134,11 +134,6 @@ static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
>  #define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT	(120 * HZ)
>  #define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT	(30 * HZ)
>  
> -static inline __s32 nf_flow_timeout_delta(unsigned int timeout)
> -{
> -	return (__s32)(timeout - (u32)jiffies);
> -}
> -
>  static void flow_offload_fixup_ct_timeout(struct nf_conn *ct)
>  {
>  	const struct nf_conntrack_l4proto *l4proto;
> @@ -232,7 +227,7 @@ int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
>  {
>  	int err;
>  
> -	flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
> +	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
>  
>  	err = rhashtable_insert_fast(&flow_table->rhashtable,
>  				     &flow->tuplehash[0].node,
> diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
> index b9e7dd6e60ce..7ea2ddc2aa93 100644
> --- a/net/netfilter/nf_flow_table_ip.c
> +++ b/net/netfilter/nf_flow_table_ip.c
> @@ -280,7 +280,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
>  	if (nf_flow_nat_ip(flow, skb, thoff, dir) < 0)
>  		return NF_DROP;
>  
> -	flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
> +	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
>  	iph = ip_hdr(skb);
>  	ip_decrease_ttl(iph);
>  	skb->tstamp = 0;
> @@ -509,7 +509,7 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
>  	if (nf_flow_nat_ipv6(flow, skb, dir) < 0)
>  		return NF_DROP;
>  
> -	flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
> +	flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
>  	ip6h = ipv6_hdr(skb);
>  	ip6h->hop_limit--;
>  	skb->tstamp = 0;
> diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
> index 6c162c954c4f..d06969af1085 100644
> --- a/net/netfilter/nf_flow_table_offload.c
> +++ b/net/netfilter/nf_flow_table_offload.c
> @@ -781,9 +781,9 @@ void nf_flow_offload_stats(struct nf_flowtable *flowtable,
>  			   struct flow_offload *flow)
>  {
>  	struct flow_offload_work *offload;
> -	s64 delta;
> +	__s32 delta;
>  
> -	delta = flow->timeout - jiffies;
> +	delta = nf_flow_timeout_delta(flow->timeout);
>  	if ((delta >= (9 * NF_FLOW_TIMEOUT) / 10) ||
>  	    flow->flags & FLOW_OFFLOAD_HW_DYING)
>  		return;