This commit implements TCP segmentation offload in TAP.
librte_gso library is used to segment large TCP payloads (e.g. packets
of 64K bytes size) into smaller MTU size buffers.
By supporting TSO offload capability in software a TAP device can be used
as a failsafe sub device and be paired with another PCI device which
supports TSO capability in HW.
For more details on librte_gso implementation please refer to dpdk
documentation.
The number of newly generated TCP TSO segments is limited to 64.
Reviewed-by: Raslan Darawsheh <rasl...@mellanox.com>
Signed-off-by: Ophir Munk <ophi...@mellanox.com>
---
drivers/net/tap/Makefile | 2 +-
drivers/net/tap/rte_eth_tap.c | 158 +++++++++++++++++++++++++++++++++++-------
drivers/net/tap/rte_eth_tap.h | 4 ++
mk/rte.app.mk | 4 +-
4 files changed, 139 insertions(+), 29 deletions(-)
diff --git a/drivers/net/tap/Makefile b/drivers/net/tap/Makefile
index ccc5c5f..3243365 100644
--- a/drivers/net/tap/Makefile
+++ b/drivers/net/tap/Makefile
@@ -24,7 +24,7 @@ CFLAGS += -I.
CFLAGS += $(WERROR_FLAGS)
LDLIBS += -lrte_eal -lrte_mbuf -lrte_mempool -lrte_ring
LDLIBS += -lrte_ethdev -lrte_net -lrte_kvargs -lrte_hash
-LDLIBS += -lrte_bus_vdev
+LDLIBS += -lrte_bus_vdev -lrte_gso
CFLAGS += -DTAP_MAX_QUEUES=$(TAP_MAX_QUEUES)
diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 538acae..c535418 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -17,6 +17,7 @@
#include <rte_ip.h>
#include <rte_string_fns.h>
+#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
@@ -54,6 +55,9 @@
#define ETH_TAP_CMP_MAC_FMT "0123456789ABCDEFabcdef"
#define ETH_TAP_MAC_ARG_FMT ETH_TAP_MAC_FIXED "|" ETH_TAP_USR_MAC_FMT
+#define TAP_GSO_MBUFS_NUM 128
+#define TAP_GSO_MBUF_SEG_SIZE 128
+
static struct rte_vdev_driver pmd_tap_drv;
static struct rte_vdev_driver pmd_tun_drv;
@@ -405,7 +409,8 @@ tap_tx_offload_get_queue_capa(void)
return DEV_TX_OFFLOAD_MULTI_SEGS |
DEV_TX_OFFLOAD_IPV4_CKSUM |
DEV_TX_OFFLOAD_UDP_CKSUM |
- DEV_TX_OFFLOAD_TCP_CKSUM;
+ DEV_TX_OFFLOAD_TCP_CKSUM |
+ DEV_TX_OFFLOAD_TCP_TSO;
}
static bool
@@ -488,23 +493,15 @@ tap_tx_l3_cksum(char *packet, uint64_t ol_flags, unsigned
int l2_len,
}
}
-/* Callback to handle sending packets from the tap interface
- */
-static uint16_t
-pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
+static inline void
+tap_write_mbufs(struct tx_queue *txq, uint16_t num_mbufs,
+ struct rte_mbuf **pmbufs, uint16_t l234_hlen,
+ uint16_t *num_packets, unsigned long *num_tx_bytes)
{
- struct tx_queue *txq = queue;
- uint16_t num_tx = 0;
- unsigned long num_tx_bytes = 0;
- uint32_t max_size;
int i;
- if (unlikely(nb_pkts == 0))
- return 0;
-
- max_size = *txq->mtu + (ETHER_HDR_LEN + ETHER_CRC_LEN + 4);
- for (i = 0; i < nb_pkts; i++) {
- struct rte_mbuf *mbuf = bufs[num_tx];
+ for (i = 0; i < num_mbufs; i++) {
+ struct rte_mbuf *mbuf = pmbufs[i];
struct iovec iovecs[mbuf->nb_segs + 2];
struct tun_pi pi = { .flags = 0, .proto = 0x00 };
struct rte_mbuf *seg = mbuf;
@@ -512,8 +509,7 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t
nb_pkts)
int proto;
int n;
int j;
- int k; /* first index in iovecs for copying segments */
- uint16_t l234_hlen; /* length of layers 2,3,4 headers */
+ int k; /* current index in iovecs for copying segments */
uint16_t seg_len; /* length of first segment */
uint16_t nb_segs;
uint16_t *l4_cksum; /* l4 checksum (pseudo header + payload) */
@@ -521,9 +517,6 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t
nb_pkts)
uint16_t l4_phdr_cksum = 0; /* TCP/UDP pseudo header checksum */
uint16_t is_cksum = 0; /* in case cksum should be offloaded */
- /* stats.errs will be incremented */
- if (rte_pktmbuf_pkt_len(mbuf) > max_size)
- break;
l4_cksum = NULL;
/*
* TUN and TAP are created with IFF_NO_PI disabled.
@@ -557,9 +550,8 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t
nb_pkts)
l234_hlen = mbuf->l2_len + mbuf->l3_len + mbuf->l4_len;
if (seg_len < l234_hlen)
break;
-
- /* To change checksums, work on a
- * copy of l2, l3 l4 headers.
+ /* To change checksums, work on a * copy of l2, l3
+ * headers + l4 pseudo header
*/
rte_memcpy(m_copy, rte_pktmbuf_mtod(mbuf, void *),
l234_hlen);
@@ -601,13 +593,80 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs,
uint16_t nb_pkts)
n = writev(txq->fd, iovecs, j);
if (n <= 0)
break;
+ (*num_packets)++;
+ (*num_tx_bytes) += rte_pktmbuf_pkt_len(mbuf);
+ }
+}
+/* Callback to handle sending packets from the tap interface
+ */
+static uint16_t
+pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
+{
+ struct tx_queue *txq = queue;
+ uint16_t num_tx = 0;
+ uint16_t num_packets = 0;
+ unsigned long num_tx_bytes = 0;
+ uint16_t tso_segsz = 0;
+ uint16_t hdrs_len;
+ uint32_t max_size;
+ int i;
+ uint64_t tso;
+ int ret;
+
+ if (unlikely(nb_pkts == 0))
+ return 0;
+
+ struct rte_mbuf *gso_mbufs[MAX_GSO_MBUFS];
+ max_size = *txq->mtu + (ETHER_HDR_LEN + ETHER_CRC_LEN + 4);
+ for (i = 0; i < nb_pkts; i++) {
+ struct rte_mbuf *mbuf_in = bufs[num_tx];
+ struct rte_mbuf **mbuf;
+ uint16_t num_mbufs;
+
+ tso = mbuf_in->ol_flags & PKT_TX_TCP_SEG;
+ if (tso) {
+ struct rte_gso_ctx *gso_ctx = &txq->gso_ctx;
+ assert(gso_ctx != NULL);
+ /* TCP segmentation implies TCP checksum offload */
+ mbuf_in->ol_flags |= PKT_TX_TCP_CKSUM;
+ /* gso size is calculated without ETHER_CRC_LEN */
+ hdrs_len = mbuf_in->l2_len + mbuf_in->l3_len +
+ mbuf_in->l4_len;
+ tso_segsz = mbuf_in->tso_segsz + hdrs_len;
+ if (unlikely(tso_segsz == hdrs_len) ||
+ tso_segsz > *txq->mtu) {
+ txq->stats.errs++;
+ break;
+ }
+ gso_ctx->gso_size = tso_segsz;
+ ret = rte_gso_segment(mbuf_in, /* packet to segment */
+ gso_ctx, /* gso control block */
+ (struct rte_mbuf **)&gso_mbufs, /* out mbufs */
+ RTE_DIM(gso_mbufs)); /* max tso mbufs */
+
+ /* ret contains the number of new created mbufs */
+ if (ret < 0)
+ break;
+
+ mbuf = gso_mbufs;
+ num_mbufs = ret;
+ } else {
+ /* stats.errs will be incremented */
+ if (rte_pktmbuf_pkt_len(mbuf_in) > max_size)
+ break;
+
+ mbuf = &mbuf_in;
+ num_mbufs = 1;
+ }
+
+ tap_write_mbufs(txq, num_mbufs, mbuf, hdrs_len,
+ &num_packets, &num_tx_bytes);
num_tx++;
- num_tx_bytes += mbuf->pkt_len;
- rte_pktmbuf_free(mbuf);
+ rte_pktmbuf_free(mbuf_in);
}
- txq->stats.opackets += num_tx;
+ txq->stats.opackets += num_packets;
txq->stats.errs += nb_pkts - num_tx;
txq->stats.obytes += num_tx_bytes;
@@ -1060,31 +1119,73 @@ tap_mac_set(struct rte_eth_dev *dev, struct ether_addr
*mac_addr)
}
static int
+tap_gso_ctx_setup(struct rte_gso_ctx *gso_ctx, struct rte_eth_dev *dev)
+{
+ uint32_t gso_types;
+ char pool_name[64];
+
+ /*
+ * Create private mbuf pool with TAP_GSO_MBUF_SEG_SIZE bytes
+ * size per mbuf use this pool for both direct and indirect mbufs
+ */
+
+ struct rte_mempool *mp; /* Mempool for GSO packets */
+ /* initialize GSO context */
+ gso_types = DEV_TX_OFFLOAD_TCP_TSO;
+ snprintf(pool_name, sizeof(pool_name), "mp_%s", dev->device->name);
+ mp = rte_mempool_lookup((const char *)pool_name);
+ if (!mp) {
+ mp = rte_pktmbuf_pool_create(pool_name, TAP_GSO_MBUFS_NUM,
+ 0, 0, RTE_PKTMBUF_HEADROOM + TAP_GSO_MBUF_SEG_SIZE,
+ SOCKET_ID_ANY);
+ if (!mp) {
+ struct pmd_internals *pmd = dev->data->dev_private;
+ RTE_LOG(DEBUG, PMD, "%s: failed to create mbuf pool for
device %s\n",
+ pmd->name, dev->device->name);
+ return -1;
+ }
+ }
+
+ gso_ctx->direct_pool = mp;
+ gso_ctx->indirect_pool = mp;
+ gso_ctx->gso_types = gso_types;
+ gso_ctx->gso_size = 0; /* gso_size is set in tx_burst() per packet */
+ gso_ctx->flag = 0;
+
+ return 0;
+}
+
+static int
tap_setup_queue(struct rte_eth_dev *dev,
struct pmd_internals *internals,
uint16_t qid,
int is_rx)
{
+ int ret;
int *fd;
int *other_fd;
const char *dir;
struct pmd_internals *pmd = dev->data->dev_private;
struct rx_queue *rx = &internals->rxq[qid];
struct tx_queue *tx = &internals->txq[qid];
+ struct rte_gso_ctx *gso_ctx;
if (is_rx) {
fd = &rx->fd;
other_fd = &tx->fd;
dir = "rx";
+ gso_ctx = NULL;
} else {
fd = &tx->fd;
other_fd = &rx->fd;
dir = "tx";
+ gso_ctx = &tx->gso_ctx;
}
if (*fd != -1) {
/* fd for this queue already exists */
TAP_LOG(DEBUG, "%s: fd %d for %s queue qid %d exists",
pmd->name, *fd, dir, qid);
+ gso_ctx = NULL;
} else if (*other_fd != -1) {
/* Only other_fd exists. dup it */
*fd = dup(*other_fd);
@@ -1109,6 +1210,11 @@ tap_setup_queue(struct rte_eth_dev *dev,
tx->mtu = &dev->data->mtu;
rx->rxmode = &dev->data->dev_conf.rxmode;
+ if (gso_ctx) {
+ ret = tap_gso_ctx_setup(gso_ctx, dev);
+ if (ret)
+ return -1;
+ }
return *fd;
}
diff --git a/drivers/net/tap/rte_eth_tap.h b/drivers/net/tap/rte_eth_tap.h
index 67c9d4b..babe42d 100644
--- a/drivers/net/tap/rte_eth_tap.h
+++ b/drivers/net/tap/rte_eth_tap.h
@@ -15,6 +15,7 @@
#include <rte_ethdev_driver.h>
#include <rte_ether.h>
+#include <rte_gso.h>
#include "tap_log.h"
#ifdef IFF_MULTI_QUEUE
@@ -23,6 +24,8 @@
#define RTE_PMD_TAP_MAX_QUEUES 1
#endif
+#define MAX_GSO_MBUFS 64
+
struct pkt_stats {
uint64_t opackets; /* Number of output packets */
uint64_t ipackets; /* Number of input packets */
@@ -51,6 +54,7 @@ struct tx_queue {
uint16_t *mtu; /* Pointer to MTU from dev_data */
uint16_t csum:1; /* Enable checksum offloading */
struct pkt_stats stats; /* Stats for this TX queue */
+ struct rte_gso_ctx gso_ctx; /* GSO context */
};
struct pmd_internals {
diff --git a/mk/rte.app.mk b/mk/rte.app.mk
index 29a2a60..62819a4 100644
--- a/mk/rte.app.mk
+++ b/mk/rte.app.mk
@@ -66,8 +66,6 @@ _LDLIBS-$(CONFIG_RTE_LIBRTE_PORT) += -lrte_port
_LDLIBS-$(CONFIG_RTE_LIBRTE_PDUMP) += -lrte_pdump
_LDLIBS-$(CONFIG_RTE_LIBRTE_DISTRIBUTOR) += -lrte_distributor
_LDLIBS-$(CONFIG_RTE_LIBRTE_IP_FRAG) += -lrte_ip_frag
-_LDLIBS-$(CONFIG_RTE_LIBRTE_GRO) += -lrte_gro
-_LDLIBS-$(CONFIG_RTE_LIBRTE_GSO) += -lrte_gso
_LDLIBS-$(CONFIG_RTE_LIBRTE_METER) += -lrte_meter
_LDLIBS-$(CONFIG_RTE_LIBRTE_LPM) += -lrte_lpm
# librte_acl needs --whole-archive because of weak functions
@@ -85,6 +83,8 @@ _LDLIBS-$(CONFIG_RTE_LIBRTE_EFD) += -lrte_efd
_LDLIBS-y += --whole-archive
_LDLIBS-$(CONFIG_RTE_LIBRTE_CFGFILE) += -lrte_cfgfile
+_LDLIBS-$(CONFIG_RTE_LIBRTE_GRO) += -lrte_gro
+_LDLIBS-$(CONFIG_RTE_LIBRTE_GSO) += -lrte_gso
_LDLIBS-$(CONFIG_RTE_LIBRTE_HASH) += -lrte_hash
_LDLIBS-$(CONFIG_RTE_LIBRTE_MEMBER) += -lrte_member
_LDLIBS-$(CONFIG_RTE_LIBRTE_VHOST) += -lrte_vhost
--
2.7.4
