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tuntap: split out XDP logic 

This patch split out XDP logic into a single function. This make it to
be reused by XDP batching path in the following patch.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2018-09-12 11:17:04 +08:00 committed by David S. Miller
parent ac1f1f6c5a
commit 8ae1aff0b3
1 changed files with 51 additions and 37 deletions
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88
drivers/net/tun.c
View File

@ -1636,14 +1636,14 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile,
}
static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf,
int buflen, int len, int pad, int delta)
int buflen, int len, int pad)
{
struct sk_buff *skb = build_skb(buf, buflen);
if (!skb)
return ERR_PTR(-ENOMEM);
skb_reserve(skb, pad - delta);
skb_reserve(skb, pad);
skb_put(skb, len);
get_page(alloc_frag->page);
@ -1652,6 +1652,39 @@ static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf,
return skb;
}
static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,
struct xdp_buff *xdp, u32 act)
{
int err;
switch (act) {
case XDP_REDIRECT:
err = xdp_do_redirect(tun->dev, xdp, xdp_prog);
xdp_do_flush_map();
if (err)
return err;
break;
case XDP_TX:
err = tun_xdp_tx(tun->dev, xdp);
if (err < 0)
return err;
break;
case XDP_PASS:
break;
default:
bpf_warn_invalid_xdp_action(act);
/* fall through */
case XDP_ABORTED:
trace_xdp_exception(tun->dev, xdp_prog, act);
/* fall through */
case XDP_DROP:
this_cpu_inc(tun->pcpu_stats->rx_dropped);
break;
}
return act;
}
static struct sk_buff *tun_build_skb(struct tun_struct *tun,
struct tun_file *tfile,
struct iov_iter *from,
@ -1661,10 +1694,10 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
struct page_frag *alloc_frag = &current->task_frag;
struct bpf_prog *xdp_prog;
int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
unsigned int delta = 0;
char *buf;
size_t copied;
int err, pad = TUN_RX_PAD;
int pad = TUN_RX_PAD;
int err = 0;
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
@ -1690,7 +1723,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
*/
if (hdr->gso_type || !xdp_prog) {
*skb_xdp = 1;
return __tun_build_skb(alloc_frag, buf, buflen, len, pad, delta);
return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
}
*skb_xdp = 0;
@ -1698,9 +1731,8 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
local_bh_disable();
rcu_read_lock();
xdp_prog = rcu_dereference(tun->xdp_prog);
if (xdp_prog && !*skb_xdp) {
if (xdp_prog) {
struct xdp_buff xdp;
void *orig_data;
u32 act;
xdp.data_hard_start = buf;
@ -1708,49 +1740,31 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
xdp_set_data_meta_invalid(&xdp);
xdp.data_end = xdp.data + len;
xdp.rxq = &tfile->xdp_rxq;
orig_data = xdp.data;
act = bpf_prog_run_xdp(xdp_prog, &xdp);
switch (act) {
case XDP_REDIRECT:
act = bpf_prog_run_xdp(xdp_prog, &xdp);
if (act == XDP_REDIRECT || act == XDP_TX) {
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
xdp_do_flush_map();
if (err)
goto err_redirect;
goto out;
case XDP_TX:
get_page(alloc_frag->page);
alloc_frag->offset += buflen;
if (tun_xdp_tx(tun->dev, &xdp) < 0)
goto err_redirect;
goto out;
case XDP_PASS:
delta = orig_data - xdp.data;
len = xdp.data_end - xdp.data;
break;
default:
bpf_warn_invalid_xdp_action(act);
/* fall through */
case XDP_ABORTED:
trace_xdp_exception(tun->dev, xdp_prog, act);
/* fall through */
case XDP_DROP:
goto out;
}
err = tun_xdp_act(tun, xdp_prog, &xdp, act);
if (err < 0)
goto err_xdp;
if (err != XDP_PASS)
goto out;
pad = xdp.data - xdp.data_hard_start;
len = xdp.data_end - xdp.data;
}
rcu_read_unlock();
local_bh_enable();
return __tun_build_skb(alloc_frag, buf, buflen, len, pad, delta);
return __tun_build_skb(alloc_frag, buf, buflen, len, pad);
err_redirect:
err_xdp:
put_page(alloc_frag->page);
out:
rcu_read_unlock();
local_bh_enable();
this_cpu_inc(tun->pcpu_stats->rx_dropped);
return NULL;
}