From 7f953ab2ba46e8649537942c0a64668ca2ce5cc5 Mon Sep 17 00:00:00 2001 From: Sowmini Varadhan Date: Tue, 3 Jan 2017 06:31:47 -0800 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- Documentation/networking/packet_mmap.txt | 9 ++++-- net/packet/af_packet.c | 39 ++++++++++++++++++------ 2 files changed, 37 insertions(+), 11 deletions(-) diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index daa015af16a0..f3b9e507ab05 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -565,7 +565,7 @@ TPACKET_V1 --> TPACKET_V2: (void *)hdr + TPACKET_ALIGN(sizeof(struct tpacket_hdr)) TPACKET_V2 --> TPACKET_V3: - - Flexible buffer implementation: + - Flexible buffer implementation for RX_RING: 1. Blocks can be configured with non-static frame-size 2. Read/poll is at a block-level (as opposed to packet-level) 3. Added poll timeout to avoid indefinite user-space wait @@ -574,7 +574,12 @@ TPACKET_V2 --> TPACKET_V3: 4.1 block::timeout 4.2 tpkt_hdr::sk_rxhash - RX Hash data available in user space - - Currently only RX_RING available + - TX_RING semantics are conceptually similar to TPACKET_V2; + use tpacket3_hdr instead of tpacket2_hdr, and TPACKET3_HDRLEN + instead of TPACKET2_HDRLEN. In the current implementation, + the tp_next_offset field in the tpacket3_hdr MUST be set to + zero, indicating that the ring does not hold variable sized frames. + Packets with non-zero values of tp_next_offset will be dropped. ------------------------------------------------------------------------------- + AF_PACKET fanout mode diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index b9e1a13b4ba3..7e39087d519b 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; -- 2.20.1