From 8ae1aff0b331ab154c39910f2e0ed239bf942d56 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 12 Sep 2018 11:17:04 +0800 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- drivers/net/tun.c | 88 ++++++++++++++++++++++++++++++++----------------------- 1 file changed, 51 insertions(+), 37 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 946c6148ed75..14fe94098180 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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 = ¤t->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: - 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: + act = bpf_prog_run_xdp(xdp_prog, &xdp); + if (act == XDP_REDIRECT || act == 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; } -- 2.11.0