A typical topology is shown below:
veth<--------veth-peer
1 |
|2
|
bridge<------->eth0(such as mlnx5 NIC)
If you use af_xdp to send packets from veth to a physical NIC,
it needs to go through some software paths, so we can refer to
the implementation of kernel GSO. When af_xdp sends packets out
from veth, consider aggregating packets and send a large packet
from the veth virtual NIC to the physical NIC.
performance:(test weth libxdp lib)
AF_XDP without batch : 480 Kpps (with ksoftirqd 100% cpu)
AF_XDP with batch : 1.5 Mpps (with ksoftirqd 15% cpu)
With af_xdp batch, the libxdp user-space program reaches a bottleneck.
Therefore, the softirq did not reach the limit.
Signed-off-by: huangjie.albert <huangjie.albert@xxxxxxxxxxxxx>
---
drivers/net/veth.c | 264 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 249 insertions(+), 15 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index e4f1a8345f42..b0dbd21089c8 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -29,6 +29,7 @@
#include <net/page_pool.h>
#include <net/xdp_sock_drv.h>
#include <net/xdp.h>
+#include <net/udp.h>
#define DRV_NAME "veth"
#define DRV_VERSION "1.0"
@@ -103,6 +104,18 @@ struct veth_xdp_tx_bq {
unsigned int count;
};
+struct veth_gso_tuple {
+ __u8 protocol;
+ __be32 saddr;
+ __be32 daddr;
+ __be16 source;
+ __be16 dest;
+ __be16 gso_size;
+ __be16 gso_segs;
+ bool gso_enable;
+ bool gso_flush;
+};
+
struct veth_seg_info {
u32 segs;
u64 desc[] ____cacheline_aligned_in_smp;
@@ -650,6 +663,84 @@ static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
return 0;
}
+static struct sk_buff *veth_build_gso_head_skb(struct net_device *dev, char *buff, u32 tot_len, u32 headroom, u32 iph_len, u32 th_len)
+{
+ struct sk_buff *skb = NULL;
+ int err = 0;
+
+ skb = alloc_skb(tot_len, GFP_KERNEL);
+ if (unlikely(!skb))
+ return NULL;
+
+ /* header room contains the eth header */
+ skb_reserve(skb, headroom - ETH_HLEN);
+
+ skb_put(skb, ETH_HLEN + iph_len + th_len);
+
+ skb_shinfo(skb)->gso_segs = 0;
+
+ err = skb_store_bits(skb, 0, buff, ETH_HLEN + iph_len + th_len);
+ if (unlikely(err)) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ skb->protocol = eth_type_trans(skb, dev);
+ skb->network_header = skb->mac_header + ETH_HLEN;
+ skb->transport_header = skb->network_header + iph_len;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+
+ return skb;
+}
+
+static inline bool gso_segment_match(struct veth_gso_tuple *gso_tuple, struct iphdr *iph, struct udphdr *udph)
+{
+ if (gso_tuple->protocol == iph->protocol &&
+ gso_tuple->saddr == iph->saddr &&
+ gso_tuple->daddr == iph->daddr &&
+ gso_tuple->source == udph->source &&
+ gso_tuple->dest == udph->dest &&
+ gso_tuple->gso_size == ntohs(udph->len))
+ {
+ gso_tuple->gso_flush = false;
+ return true;
+ } else {
+ gso_tuple->gso_flush = true;
+ return false;
+ }
+}
+
+static inline void gso_tuple_init(struct veth_gso_tuple *gso_tuple, struct iphdr *iph, struct udphdr *udph)
+{
+ gso_tuple->protocol = iph->protocol;
+ gso_tuple->saddr = iph->saddr;
+ gso_tuple->daddr = iph->daddr;
+ gso_tuple->source = udph->source;
+ gso_tuple->dest = udph->dest;
+ gso_tuple->gso_flush = false;
+ gso_tuple->gso_size = ntohs(udph->len);
+ gso_tuple->gso_segs = 0;
+}
+
+/* only ipv4 udp support gso now */
+static inline bool ip_hdr_gso_check(unsigned char *buff, u32 len)
+{
+ struct iphdr *iph;
+
+ if (len <= (ETH_HLEN + sizeof(*iph)))
+ return false;
+
+ iph = (struct iphdr *)(buff + ETH_HLEN);
+
+ /*
+ * check for ip headers, if the data support gso
+ */
+ if (iph->ihl < 5 || iph->version != 4 || len < (iph->ihl * 4 + ETH_HLEN) || iph->protocol != IPPROTO_UDP)
+ return false;
+
+ return true;
+}
+
static struct sk_buff *veth_build_skb(void *head, int headroom, int len,
int buflen)
{
@@ -686,8 +777,8 @@ static void veth_xsk_destruct_skb(struct sk_buff *skb)
skb_shinfo(skb)->destructor_arg_xsk_pool = NULL;
}
-static struct sk_buff *veth_build_skb_zerocopy(struct net_device *dev, struct xsk_buff_pool *pool,
- struct xdp_desc *desc)
+static struct sk_buff *veth_build_skb_zerocopy_normal(struct net_device *dev,
+ struct xsk_buff_pool *pool, struct xdp_desc *desc)
{
struct veth_seg_info *seg_info;
struct sk_buff *skb;
@@ -698,45 +789,133 @@ static struct sk_buff *veth_build_skb_zerocopy(struct net_device *dev, struct xs
int headroom;
u64 addr;
u32 index;
-
addr = desc->addr;
len = desc->len;
buffer = xsk_buff_raw_get_data(pool, addr);
ts = pool->unaligned ? len : pool->chunk_size;
-
headroom = offset_in_page(buffer);
-
/* offset in umem pool buffer */
addr = buffer - pool->addrs;
-
/* get the page of the desc */
page = pool->umem->pgs[addr >> PAGE_SHIFT];
-
/* in order to avoid to get freed by kfree_skb */
get_page(page);
-
hard_start = page_to_virt(page);
-
skb = veth_build_skb(hard_start, headroom, len, ts);
seg_info = (struct veth_seg_info *)kmalloc(struct_size(seg_info, desc, MAX_SKB_FRAGS), GFP_KERNEL);
if (!seg_info)
{
printk("here must to deal with\n");
}
-
/* later we will support gso for this */
index = skb_shinfo(skb)->gso_segs;
seg_info->desc[index] = desc->addr;
seg_info->segs = ++index;
-
skb->truesize += ts;
skb->dev = dev;
skb_shinfo(skb)->destructor_arg = (void *)(long)seg_info;
skb_shinfo(skb)->destructor_arg_xsk_pool = (void *)(long)pool;
skb->destructor = veth_xsk_destruct_skb;
-
/* set the mac header */
skb->protocol = eth_type_trans(skb, dev);
+ /* to do, add skb to sock. may be there is no need to do for this
+ * refcount_add(ts, &xs->sk.sk_wmem_alloc);
+ */
+ return skb;
+}
+
+static struct sk_buff *veth_build_skb_zerocopy_gso(struct net_device *dev, struct xsk_buff_pool *pool,
+ struct xdp_desc *desc, struct veth_gso_tuple *gso_tuple, struct sk_buff *prev_skb)
+{
+ u32 hr, len, ts, index, iph_len, th_len, data_offset, data_len, tot_len;
+ struct veth_seg_info *seg_info;
+ void *buffer;
+ struct udphdr *udph;
+ struct iphdr *iph;
+ struct sk_buff *skb;
+ struct page *page;
+ int hh_len = 0;
+ u64 addr;
+
+ addr = desc->addr;
+ len = desc->len;
+
+ /* l2 reserved len */
+ hh_len = LL_RESERVED_SPACE(dev);
+ hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(hh_len));
+
+ /* data points to eth header */
+ buffer = (unsigned char *)xsk_buff_raw_get_data(pool, addr);
+
+ iph = (struct iphdr *)(buffer + ETH_HLEN);
+ iph_len = iph->ihl * 4;
+
+ udph = (struct udphdr *)(buffer + ETH_HLEN + iph_len);
+ th_len = sizeof(struct udphdr);
+
+ if (gso_tuple->gso_flush)
+ gso_tuple_init(gso_tuple, iph, udph);
+
+ ts = pool->unaligned ? len : pool->chunk_size;
+
+ data_offset = offset_in_page(buffer) + ETH_HLEN + iph_len + th_len;
+ data_len = len - (ETH_HLEN + iph_len + th_len);
+
+ /* head is null or this is a new 5 tuple */
+ if (NULL == prev_skb || !gso_segment_match(gso_tuple, iph, udph)) {
+ tot_len = hr + iph_len + th_len;
+ skb = veth_build_gso_head_skb(dev, buffer, tot_len, hr, iph_len, th_len);
+ if (!skb) {
+ /* to do: handle here for skb */
+ return NULL;
+ }
+
+ /* store information for gso */
+ seg_info = (struct veth_seg_info *)kmalloc(struct_size(seg_info, desc, MAX_SKB_FRAGS), GFP_KERNEL);
+ if (!seg_info) {
+ /* to do */
+ kfree_skb(skb);
+ return NULL;
+ }
+ } else {
+ skb = prev_skb;
+ skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4 | SKB_GSO_PARTIAL;
+ skb_shinfo(skb)->gso_size = data_len;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+
+ /* max segment is MAX_SKB_FRAGS */
+ if(skb_shinfo(skb)->gso_segs >= MAX_SKB_FRAGS - 1) {
+ gso_tuple->gso_flush = true;
+ }
+ seg_info = (struct veth_seg_info *)skb_shinfo(skb)->destructor_arg;
+ }
+
+ /* offset in umem pool buffer */
+ addr = buffer - pool->addrs;
+
+ /* get the page of the desc */
+ page = pool->umem->pgs[addr >> PAGE_SHIFT];
+
+ /* in order to avoid to get freed by kfree_skb */
+ get_page(page);
+
+ /* desc.data can not hold in two */
+ skb_fill_page_desc(skb, skb_shinfo(skb)->gso_segs, page, data_offset, data_len);
+
+ skb->len += data_len;
+ skb->data_len += data_len;
+ skb->truesize += ts;
+ skb->dev = dev;
+
+ /* later we will support gso for this */
+ index = skb_shinfo(skb)->gso_segs;
+ seg_info->desc[index] = desc->addr;
+ seg_info->segs = ++index;
+ skb_shinfo(skb)->gso_segs++;
+
+ skb_shinfo(skb)->destructor_arg = (void *)(long)seg_info;
+ skb_shinfo(skb)->destructor_arg_xsk_pool = (void *)(long)pool;
+ skb->destructor = veth_xsk_destruct_skb;
/* to do, add skb to sock. may be there is no need to do for this
* refcount_add(ts, &xs->sk.sk_wmem_alloc);
@@ -744,6 +923,22 @@ static struct sk_buff *veth_build_skb_zerocopy(struct net_device *dev, struct xs
return skb;
}
+static inline struct sk_buff *veth_build_skb_zerocopy(struct net_device *dev, struct xsk_buff_pool *pool,
+ struct xdp_desc *desc, struct veth_gso_tuple *gso_tuple, struct sk_buff *prev_skb)
+{
+ void *buffer;
+
+ buffer = xsk_buff_raw_get_data(pool, desc->addr);
+ if (ip_hdr_gso_check(buffer, desc->len)) {
+ gso_tuple->gso_enable = true;
+ return veth_build_skb_zerocopy_gso(dev, pool, desc, gso_tuple, prev_skb);
+ } else {
+ gso_tuple->gso_flush = false;
+ gso_tuple->gso_enable = false;
+ return veth_build_skb_zerocopy_normal(dev, pool, desc);
+ }
+}
+
static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
struct xdp_frame *frame,
struct veth_xdp_tx_bq *bq,
@@ -1176,16 +1371,33 @@ static inline bool buffer_in_page(void *buffer, u32 len)
}
}
+static inline void veth_skb_gso_check_update(struct sk_buff *skb)
+{
+ struct iphdr *iph = ip_hdr(skb);
+ struct udphdr *uh = udp_hdr(skb);
+ int ip_tot_len = skb->len;
+ int udp_len = skb->len - (skb->transport_header - skb->network_header);
+ iph->tot_len = htons(ip_tot_len);
+ ip_send_check(iph);
+ uh->len = htons(udp_len);
+ uh->check = 0;
+
+ /* udp4 checksum update */
+ udp4_hwcsum(skb, iph->saddr, iph->daddr);
+}
+
static int veth_xsk_tx_xmit(struct veth_sq *sq, struct xsk_buff_pool *xsk_pool, int budget)
{
struct veth_priv *priv, *peer_priv;
struct net_device *dev, *peer_dev;
+ struct veth_gso_tuple gso_tuple;
struct veth_rq *peer_rq;
struct veth_stats peer_stats = {};
struct veth_stats stats = {};
struct veth_xdp_tx_bq bq;
struct xdp_desc desc;
void *xdpf;
+ struct sk_buff *prev_skb = NULL;
struct sk_buff *skb = NULL;
bool zc = xsk_pool->umem->zc;
u32 xsk_headroom = xsk_pool->headroom;
@@ -1200,6 +1412,8 @@ static int veth_xsk_tx_xmit(struct veth_sq *sq, struct xsk_buff_pool *xsk_pool,
/* todo: queue index must set before this */
peer_rq = &peer_priv->rq[sq->queue_index];
+ memset(&gso_tuple, 0, sizeof(gso_tuple));
+
/* set xsk wake up flag, to do: where to disable */
if (xsk_uses_need_wakeup(xsk_pool))
xsk_set_tx_need_wakeup(xsk_pool);
@@ -1279,12 +1493,26 @@ static int veth_xsk_tx_xmit(struct veth_sq *sq, struct xsk_buff_pool *xsk_pool,
/* no need to copy address for af+xdp */
p_frame = veth_xdp_rcv_one(peer_rq, p_frame, &bq, &peer_stats);
if (p_frame) {
- skb = veth_build_skb_zerocopy(peer_dev, xsk_pool, &desc);
- if (skb) {
+ skb = veth_build_skb_zerocopy(peer_dev, xsk_pool, &desc, &gso_tuple, prev_skb);
+ if (!gso_tuple.gso_enable) {
napi_gro_receive(&peer_rq->xdp_napi, skb);
skb = NULL;
} else {
- xsk_tx_completed_addr(xsk_pool, desc.addr);
+ if (prev_skb && gso_tuple.gso_flush) {
+ veth_skb_gso_check_update(prev_skb);
+ napi_gro_receive(&peer_rq->xdp_napi, prev_skb);
+
+ if (prev_skb == skb) {
+ skb = NULL;
+ prev_skb = NULL;
+ } else {
+ prev_skb = skb;
+ }
+ } else if (NULL == skb){
+ xsk_tx_completed_addr(xsk_pool, desc.addr);
+ } else {
+ prev_skb = skb;
+ }
}
}
} else {
@@ -1308,6 +1536,12 @@ static int veth_xsk_tx_xmit(struct veth_sq *sq, struct xsk_buff_pool *xsk_pool,
done++;
}
+ /* gso skb */
+ if (NULL!=skb) {
+ veth_skb_gso_check_update(skb);
+ napi_gro_receive(&peer_rq->xdp_napi, skb);
+ }
+
/* release, move consumer，and wakeup the producer */
if (done) {
napi_schedule(&peer_rq->xdp_napi);
--
2.20.1
