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Date: Wed, 3 Feb 2016 18:02:16 -0500
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, daniel@...earbox.net, mst@...hat.com,
sri@...ibm.com, Willem de Bruijn <willemb@...gle.com>
Subject: [PATCH net-next v2 3/4] packet: parse tpacket header before skb alloc
From: Willem de Bruijn <willemb@...gle.com>
GSO packet headers must be stored in the linear skb segment.
Move tpacket header parsing before sock_alloc_send_skb. The GSO
follow-on patch will later increase the skb linear argument to
sock_alloc_send_skb if needed for large packets.
The header parsing code does not require an allocated skb, so is
safe to move. Later pass to tpacket_fill_skb the computed data
start and length.
Signed-off-by: Willem de Bruijn <willemb@...gle.com>
---
net/packet/af_packet.c | 111 +++++++++++++++++++++++++++++--------------------
1 file changed, 65 insertions(+), 46 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index b26df32..89377bf 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2494,14 +2494,13 @@ static int packet_snd_vnet_gso(struct sk_buff *skb,
}
static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
- void *frame, struct net_device *dev, int size_max,
+ void *frame, struct net_device *dev, void *data, int tp_len,
__be16 proto, unsigned char *addr, int hlen)
{
union tpacket_uhdr ph;
- int to_write, offset, len, tp_len, nr_frags, len_max;
+ int to_write, offset, len, nr_frags, len_max;
struct socket *sock = po->sk.sk_socket;
struct page *page;
- void *data;
int err;
ph.raw = frame;
@@ -2513,51 +2512,9 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
sock_tx_timestamp(&po->sk, &skb_shinfo(skb)->tx_flags);
skb_shinfo(skb)->destructor_arg = ph.raw;
- switch (po->tp_version) {
- case TPACKET_V2:
- tp_len = ph.h2->tp_len;
- break;
- default:
- tp_len = ph.h1->tp_len;
- break;
- }
- if (unlikely(tp_len > size_max)) {
- pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
- return -EMSGSIZE;
- }
-
skb_reserve(skb, hlen);
skb_reset_network_header(skb);
- if (unlikely(po->tp_tx_has_off)) {
- int off_min, off_max, off;
- off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
- off_max = po->tx_ring.frame_size - tp_len;
- if (sock->type == SOCK_DGRAM) {
- switch (po->tp_version) {
- case TPACKET_V2:
- off = ph.h2->tp_net;
- break;
- default:
- off = ph.h1->tp_net;
- break;
- }
- } else {
- switch (po->tp_version) {
- case TPACKET_V2:
- off = ph.h2->tp_mac;
- break;
- default:
- off = ph.h1->tp_mac;
- break;
- }
- }
- if (unlikely((off < off_min) || (off_max < off)))
- return -EINVAL;
- data = ph.raw + off;
- } else {
- data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll);
- }
to_write = tp_len;
if (sock->type == SOCK_DGRAM) {
@@ -2615,6 +2572,61 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
return tp_len;
}
+static int tpacket_parse_header(struct packet_sock *po, void *frame,
+ int size_max, void **data)
+{
+ union tpacket_uhdr ph;
+ int tp_len, off;
+
+ ph.raw = frame;
+
+ switch (po->tp_version) {
+ case TPACKET_V2:
+ tp_len = ph.h2->tp_len;
+ break;
+ default:
+ tp_len = ph.h1->tp_len;
+ break;
+ }
+ if (unlikely(tp_len > size_max)) {
+ pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
+ return -EMSGSIZE;
+ }
+
+ if (unlikely(po->tp_tx_has_off)) {
+ int off_min, off_max;
+
+ off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
+ off_max = po->tx_ring.frame_size - tp_len;
+ if (po->sk.sk_type == SOCK_DGRAM) {
+ switch (po->tp_version) {
+ case TPACKET_V2:
+ off = ph.h2->tp_net;
+ break;
+ default:
+ off = ph.h1->tp_net;
+ break;
+ }
+ } else {
+ switch (po->tp_version) {
+ case TPACKET_V2:
+ off = ph.h2->tp_mac;
+ break;
+ default:
+ off = ph.h1->tp_mac;
+ break;
+ }
+ }
+ if (unlikely((off < off_min) || (off_max < off)))
+ return -EINVAL;
+ } else {
+ off = po->tp_hdrlen - sizeof(struct sockaddr_ll);
+ }
+
+ *data = frame + off;
+ return tp_len;
+}
+
static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
{
struct sk_buff *skb;
@@ -2626,6 +2638,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
bool need_wait = !(msg->msg_flags & MSG_DONTWAIT);
int tp_len, size_max;
unsigned char *addr;
+ void *data;
int len_sum = 0;
int status = TP_STATUS_AVAILABLE;
int hlen, tlen;
@@ -2673,6 +2686,11 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
continue;
}
+ skb = NULL;
+ tp_len = tpacket_parse_header(po, ph, size_max, &data);
+ if (tp_len < 0)
+ goto tpacket_error;
+
status = TP_STATUS_SEND_REQUEST;
hlen = LL_RESERVED_SPACE(dev);
tlen = dev->needed_tailroom;
@@ -2686,7 +2704,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
err = len_sum;
goto out_status;
}
- tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
+ tp_len = tpacket_fill_skb(po, skb, ph, dev, data, tp_len, proto,
addr, hlen);
if (likely(tp_len >= 0) &&
tp_len > dev->mtu + reserve &&
@@ -2694,6 +2712,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
tp_len = -EMSGSIZE;
if (unlikely(tp_len < 0)) {
+tpacket_error:
if (po->tp_loss) {
__packet_set_status(po, ph,
TP_STATUS_AVAILABLE);
--
2.7.0.rc3.207.g0ac5344
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