af_packet: TX_RING support for TPACKET_V3
Although TPACKET_V3 Rx has some benefits over TPACKET_V2 Rx, *_v3
does not currently have TX_RING support. As a result an application
that wants the best perf for Tx and Rx (e.g. to handle request/response
transacations) ends up needing 2 sockets, one with *_v2 for Tx and
another with *_v3 for Rx.
This patch enables TPACKET_V2 compatible Tx features in TPACKET_V3
so that an application can use a single descriptor to get the benefits
of _v3 RX_RING and _v2 TX_RING. An application may do a block-send by
first filling up multiple frames in the Tx ring and then triggering a
transmit. This patch only support fixed size Tx frames for TPACKET_V3,
and requires that tp_next_offset must be zero.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index b9e1a13..7e39087d 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -409,6 +409,9 @@ static void __packet_set_status(struct packet_sock *po, void *frame, int status)
flush_dcache_page(pgv_to_page(&h.h2->tp_status));
break;
case TPACKET_V3:
+ h.h3->tp_status = status;
+ flush_dcache_page(pgv_to_page(&h.h3->tp_status));
+ break;
default:
WARN(1, "TPACKET version not supported.\n");
BUG();
@@ -432,6 +435,8 @@ static int __packet_get_status(struct packet_sock *po, void *frame)
flush_dcache_page(pgv_to_page(&h.h2->tp_status));
return h.h2->tp_status;
case TPACKET_V3:
+ flush_dcache_page(pgv_to_page(&h.h3->tp_status));
+ return h.h3->tp_status;
default:
WARN(1, "TPACKET version not supported.\n");
BUG();
@@ -2497,6 +2502,13 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame,
ph.raw = frame;
switch (po->tp_version) {
+ case TPACKET_V3:
+ if (ph.h3->tp_next_offset != 0) {
+ pr_warn_once("variable sized slot not supported");
+ return -EINVAL;
+ }
+ tp_len = ph.h3->tp_len;
+ break;
case TPACKET_V2:
tp_len = ph.h2->tp_len;
break;
@@ -2516,6 +2528,9 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame,
off_max = po->tx_ring.frame_size - tp_len;
if (po->sk.sk_type == SOCK_DGRAM) {
switch (po->tp_version) {
+ case TPACKET_V3:
+ off = ph.h3->tp_net;
+ break;
case TPACKET_V2:
off = ph.h2->tp_net;
break;
@@ -2525,6 +2540,9 @@ static int tpacket_parse_header(struct packet_sock *po, void *frame,
}
} else {
switch (po->tp_version) {
+ case TPACKET_V3:
+ off = ph.h3->tp_mac;
+ break;
case TPACKET_V2:
off = ph.h2->tp_mac;
break;
@@ -4113,11 +4131,6 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
struct tpacket_req *req = &req_u->req;
lock_sock(sk);
- /* Opening a Tx-ring is NOT supported in TPACKET_V3 */
- if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) {
- net_warn_ratelimited("Tx-ring is not supported.\n");
- goto out;
- }
rb = tx_ring ? &po->tx_ring : &po->rx_ring;
rb_queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
@@ -4177,11 +4190,19 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
goto out;
switch (po->tp_version) {
case TPACKET_V3:
- /* Transmit path is not supported. We checked
- * it above but just being paranoid
- */
- if (!tx_ring)
+ /* Block transmit is not supported yet */
+ if (!tx_ring) {
init_prb_bdqc(po, rb, pg_vec, req_u);
+ } else {
+ struct tpacket_req3 *req3 = &req_u->req3;
+
+ if (req3->tp_retire_blk_tov ||
+ req3->tp_sizeof_priv ||
+ req3->tp_feature_req_word) {
+ err = -EINVAL;
+ goto out;
+ }
+ }
break;
default:
break;
