2024-03-09 15:26:55

by Richard Gobert

[permalink] [raw]
Subject: [PATCH net-next v3 0/4] net: gro: encapsulation bug fix and flush checks improvements

This series fixes a bug in the complete phase of UDP in GRO, in which
socket lookup fails due to using network_header when parsing encapsulated
packets. The fix is to pass p_off parameter in *_gro_complete.

Next, the fields network_offset and inner_network_offset are added to
napi_gro_cb, and are both set during the receive phase of GRO. This is then
leveraged in the next commit to remove flush_id state from napi_gro_cb, and
stateful code in {ipv6,inet}_gro_receive which may be unnecessarily
complicated due to encapsulation support in GRO.

In addition, udpgro_fwd selftest is adjusted to include the socket lookup
case for vxlan. This selftest will test its supposed functionality once
local bind support is merged (https://lore.kernel.org/netdev/[email protected]/).

v2 -> v3:
- Use napi_gro_cb instead of skb->{offset}
- v2:
https://lore.kernel.org/netdev/[email protected]/

v1 -> v2:
- Pass p_off in *_gro_complete to fix UDP bug
- Remove more conditionals and memory fetches from inet_gro_flush
- v1:
https://lore.kernel.org/netdev/[email protected]/

Richard Gobert (4):
net: gro: add p_off param in *_gro_complete
selftests/net: add local address bind in vxlan selftest
net: gro: add {inner_}network_offset to napi_gro_cb
net: gro: move L3 flush checks to tcp_gro_receive

drivers/net/geneve.c | 7 +-
drivers/net/vxlan/vxlan_core.c | 11 ++--
include/linux/etherdevice.h | 2 +-
include/linux/netdevice.h | 3 +-
include/linux/udp.h | 2 +-
include/net/gro.h | 36 +++++++----
include/net/inet_common.h | 2 +-
include/net/tcp.h | 6 +-
include/net/udp.h | 8 +--
include/net/udp_tunnel.h | 2 +-
net/8021q/vlan_core.c | 6 +-
net/core/gro.c | 6 +-
net/ethernet/eth.c | 5 +-
net/ipv4/af_inet.c | 49 ++------------
net/ipv4/fou_core.c | 9 +--
net/ipv4/gre_offload.c | 6 +-
net/ipv4/tcp_offload.c | 79 ++++++++++++++++++-----
net/ipv4/udp.c | 3 +-
net/ipv4/udp_offload.c | 26 ++++----
net/ipv6/ip6_offload.c | 41 +++++-------
net/ipv6/tcpv6_offload.c | 7 +-
net/ipv6/udp.c | 3 +-
net/ipv6/udp_offload.c | 13 ++--
tools/testing/selftests/net/udpgro_fwd.sh | 10 ++-
24 files changed, 187 insertions(+), 155 deletions(-)

--
2.36.1



2024-03-09 15:29:38

by Richard Gobert

[permalink] [raw]
Subject: [PATCH net-next v3 1/4] net: gro: add p_off param in *_gro_complete

Commits a602456 ("udp: Add GRO functions to UDP socket") and 57c67ff ("udp:
additional GRO support") introduce incorrect usage of {ip,ipv6}_hdr in the
complete phase of gro. The functions always return skb->network_header,
which in the case of encapsulated packets at the gro complete phase, is
always set to the innermost L3 of the packet. That means that calling
{ip,ipv6}_hdr for skbs which completed the GRO receive phase (both in
gro_list and *_gro_complete) when parsing an encapsulated packet's _outer_
L3/L4 may return an unexpected value.

This incorrect usage leads to a bug in GRO's UDP socket lookup.
udp{4,6}_lib_lookup_skb functions use ip_hdr/ipv6_hdr respectively. These
*_hdr functions return network_header which will point to the innermost L3,
resulting in the wrong offset being used in __udp{4,6}_lib_lookup with
encapsulated packets.

To fix this issue p_off param is used in *_gro_complete to pass off the
offset of the previous layer.

Reproduction example:

Endpoint configuration example (fou + local address bind)

# ip fou add port 6666 ipproto 4
# ip link add name tun1 type ipip remote 2.2.2.1 local 2.2.2.2 encap fou encap-dport 5555 encap-sport 6666 mode ipip
# ip link set tun1 up
# ip a add 1.1.1.2/24 dev tun1

Netperf TCP_STREAM result on net-next before patch is applied:

net-next main, GRO enabled:
$ netperf -H 1.1.1.2 -t TCP_STREAM -l 5
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

131072 16384 16384 5.28 2.37

net-next main, GRO disabled:
$ netperf -H 1.1.1.2 -t TCP_STREAM -l 5
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

131072 16384 16384 5.01 2745.06

patch applied, GRO enabled:
$ netperf -H 1.1.1.2 -t TCP_STREAM -l 5
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

131072 16384 16384 5.01 2877.38

Fixes: 57c67ff4bd92 ("udp: additional GRO support")
Suggested-by: Eric Dumazet <[email protected]>
Signed-off-by: Richard Gobert <[email protected]>
---
drivers/net/geneve.c | 7 ++++---
drivers/net/vxlan/vxlan_core.c | 11 +++++++----
include/linux/etherdevice.h | 2 +-
include/linux/netdevice.h | 3 ++-
include/linux/udp.h | 2 +-
include/net/gro.h | 11 ++++++-----
include/net/inet_common.h | 2 +-
include/net/tcp.h | 6 ++++--
include/net/udp.h | 8 ++++----
include/net/udp_tunnel.h | 2 +-
net/8021q/vlan_core.c | 4 ++--
net/core/gro.c | 2 +-
net/ethernet/eth.c | 4 ++--
net/ipv4/af_inet.c | 8 ++++----
net/ipv4/fou_core.c | 9 +++++----
net/ipv4/gre_offload.c | 5 +++--
net/ipv4/tcp_offload.c | 7 ++++---
net/ipv4/udp.c | 3 ++-
net/ipv4/udp_offload.c | 26 ++++++++++++++------------
net/ipv6/ip6_offload.c | 22 ++++++++++++----------
net/ipv6/tcpv6_offload.c | 7 ++++---
net/ipv6/udp.c | 3 ++-
net/ipv6/udp_offload.c | 13 +++++++------
23 files changed, 93 insertions(+), 74 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index e25e0a31126c..75837b3fb2d3 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -546,7 +546,7 @@ static struct sk_buff *geneve_gro_receive(struct sock *sk,
}

static int geneve_gro_complete(struct sock *sk, struct sk_buff *skb,
- int nhoff)
+ int p_off, int nhoff)
{
struct genevehdr *gh;
struct packet_offload *ptype;
@@ -560,11 +560,12 @@ static int geneve_gro_complete(struct sock *sk, struct sk_buff *skb,

/* since skb->encapsulation is set, eth_gro_complete() sets the inner mac header */
if (likely(type == htons(ETH_P_TEB)))
- return eth_gro_complete(skb, nhoff + gh_len);
+ return eth_gro_complete(skb, p_off, nhoff + gh_len);

ptype = gro_find_complete_by_type(type);
if (ptype)
- err = ptype->callbacks.gro_complete(skb, nhoff + gh_len);
+ err = ptype->callbacks.gro_complete(skb, p_off,
+ nhoff + gh_len);

skb_set_inner_mac_header(skb, nhoff + gh_len);

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 386cbe4d3327..84c123405b70 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -767,15 +767,17 @@ static struct sk_buff *vxlan_gpe_gro_receive(struct sock *sk,
return pp;
}

-static int vxlan_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
+static int vxlan_gro_complete(struct sock *sk, struct sk_buff *skb,
+ int p_off, int nhoff)
{
/* Sets 'skb->inner_mac_header' since we are always called with
* 'skb->encapsulation' set.
*/
- return eth_gro_complete(skb, nhoff + sizeof(struct vxlanhdr));
+ return eth_gro_complete(skb, p_off, nhoff + sizeof(struct vxlanhdr));
}

-static int vxlan_gpe_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
+static int vxlan_gpe_gro_complete(struct sock *sk, struct sk_buff *skb,
+ int p_off, int nhoff)
{
struct vxlanhdr *vh = (struct vxlanhdr *)(skb->data + nhoff);
const struct packet_offload *ptype;
@@ -786,7 +788,8 @@ static int vxlan_gpe_gro_complete(struct sock *sk, struct sk_buff *skb, int nhof
return err;
ptype = gro_find_complete_by_type(protocol);
if (ptype)
- err = ptype->callbacks.gro_complete(skb, nhoff + sizeof(struct vxlanhdr));
+ err = ptype->callbacks.gro_complete(skb, p_off, nhoff +
+ sizeof(struct vxlanhdr));
return err;
}

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 224645f17c33..b081b43d9686 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -64,7 +64,7 @@ struct net_device *devm_alloc_etherdev_mqs(struct device *dev, int sizeof_priv,
#define devm_alloc_etherdev(dev, sizeof_priv) devm_alloc_etherdev_mqs(dev, sizeof_priv, 1, 1)

struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb);
-int eth_gro_complete(struct sk_buff *skb, int nhoff);
+int eth_gro_complete(struct sk_buff *skb, int p_off, int nhoff);

/* Reserved Ethernet Addresses per IEEE 802.1Q */
static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c41019f34179..5a7049f83e41 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2788,7 +2788,8 @@ struct offload_callbacks {
netdev_features_t features);
struct sk_buff *(*gro_receive)(struct list_head *head,
struct sk_buff *skb);
- int (*gro_complete)(struct sk_buff *skb, int nhoff);
+ int (*gro_complete)(struct sk_buff *skb, int nhoff,
+ int thoff);
};

struct packet_offload {
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 3748e82b627b..a04d94a3b42f 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -82,7 +82,7 @@ struct udp_sock {
struct sk_buff *skb);
int (*gro_complete)(struct sock *sk,
struct sk_buff *skb,
- int nhoff);
+ int nhoff, int thoff);

/* udp_recvmsg try to use this before splicing sk_receive_queue */
struct sk_buff_head reader_queue ____cacheline_aligned_in_smp;
diff --git a/include/net/gro.h b/include/net/gro.h
index 2b58671a6549..cb7282bf3d63 100644
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -382,18 +382,18 @@ static inline void skb_gro_flush_final_remcsum(struct sk_buff *skb,

INDIRECT_CALLABLE_DECLARE(struct sk_buff *ipv6_gro_receive(struct list_head *,
struct sk_buff *));
-INDIRECT_CALLABLE_DECLARE(int ipv6_gro_complete(struct sk_buff *, int));
+INDIRECT_CALLABLE_DECLARE(int ipv6_gro_complete(struct sk_buff *, int, int));
INDIRECT_CALLABLE_DECLARE(struct sk_buff *inet_gro_receive(struct list_head *,
struct sk_buff *));
-INDIRECT_CALLABLE_DECLARE(int inet_gro_complete(struct sk_buff *, int));
+INDIRECT_CALLABLE_DECLARE(int inet_gro_complete(struct sk_buff *, int, int));

INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *,
struct sk_buff *));
-INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int));
+INDIRECT_CALLABLE_DECLARE(int udp4_gro_complete(struct sk_buff *, int, int));

INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp6_gro_receive(struct list_head *,
struct sk_buff *));
-INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));
+INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int, int));

#define indirect_call_gro_receive_inet(cb, f2, f1, head, skb) \
({ \
@@ -404,7 +404,8 @@ INDIRECT_CALLABLE_DECLARE(int udp6_gro_complete(struct sk_buff *, int));

struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
struct udphdr *uh, struct sock *sk);
-int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
+int udp_gro_complete(struct sk_buff *skb, int nhoff, int thoff,
+ udp_lookup_t lookup);

static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
{
diff --git a/include/net/inet_common.h b/include/net/inet_common.h
index f50a644d87a9..605f917c830c 100644
--- a/include/net/inet_common.h
+++ b/include/net/inet_common.h
@@ -64,7 +64,7 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len,
int *addr_len);

struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb);
-int inet_gro_complete(struct sk_buff *skb, int nhoff);
+int inet_gro_complete(struct sk_buff *skb, int nhoff, int thoff);
struct sk_buff *inet_gso_segment(struct sk_buff *skb,
netdev_features_t features);

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 6ae35199d3b3..f36f15b6fb49 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -2196,9 +2196,11 @@ void tcp_v4_destroy_sock(struct sock *sk);
struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
netdev_features_t features);
struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb);
-INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int thoff));
+INDIRECT_CALLABLE_DECLARE(int tcp4_gro_complete(struct sk_buff *skb, int nhoff,
+ int thoff));
INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb));
-INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int thoff));
+INDIRECT_CALLABLE_DECLARE(int tcp6_gro_complete(struct sk_buff *skb, int nhoff,
+ int thoff));
INDIRECT_CALLABLE_DECLARE(struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb));
#ifdef CONFIG_INET
void tcp_gro_complete(struct sk_buff *skb);
diff --git a/include/net/udp.h b/include/net/udp.h
index 488a6d2babcc..601d1c3b677a 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -166,8 +166,8 @@ static inline void udp_csum_pull_header(struct sk_buff *skb)
UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
}

-typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
- __be16 dport);
+typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, int nhoff,
+ __be16 sport, __be16 dport);

void udp_v6_early_demux(struct sk_buff *skb);
INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
@@ -301,7 +301,7 @@ struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
__be32 daddr, __be16 dport, int dif, int sdif,
struct udp_table *tbl, struct sk_buff *skb);
-struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
+struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, int nhoff,
__be16 sport, __be16 dport);
struct sock *udp6_lib_lookup(struct net *net,
const struct in6_addr *saddr, __be16 sport,
@@ -312,7 +312,7 @@ struct sock *__udp6_lib_lookup(struct net *net,
const struct in6_addr *daddr, __be16 dport,
int dif, int sdif, struct udp_table *tbl,
struct sk_buff *skb);
-struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
+struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, int nhoff,
__be16 sport, __be16 dport);
int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);

diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index d716214fe03d..a641392e70b0 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -75,7 +75,7 @@ typedef struct sk_buff *(*udp_tunnel_gro_receive_t)(struct sock *sk,
struct list_head *head,
struct sk_buff *skb);
typedef int (*udp_tunnel_gro_complete_t)(struct sock *sk, struct sk_buff *skb,
- int nhoff);
+ int nhoff, int thoff);

struct udp_tunnel_sock_cfg {
void *sk_user_data; /* user data used by encap_rcv call back */
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index f00158234505..247704cf70af 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -510,7 +510,7 @@ static struct sk_buff *vlan_gro_receive(struct list_head *head,
return pp;
}

-static int vlan_gro_complete(struct sk_buff *skb, int nhoff)
+static int vlan_gro_complete(struct sk_buff *skb, int p_off, int nhoff)
{
struct vlan_hdr *vhdr = (struct vlan_hdr *)(skb->data + nhoff);
__be16 type = vhdr->h_vlan_encapsulated_proto;
@@ -521,7 +521,7 @@ static int vlan_gro_complete(struct sk_buff *skb, int nhoff)
if (ptype)
err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
ipv6_gro_complete, inet_gro_complete,
- skb, nhoff + sizeof(*vhdr));
+ skb, p_off, nhoff + sizeof(*vhdr));

return err;
}
diff --git a/net/core/gro.c b/net/core/gro.c
index 6a0edbd826a1..7da3df2c634f 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -254,7 +254,7 @@ static void napi_gro_complete(struct napi_struct *napi, struct sk_buff *skb)

err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
ipv6_gro_complete, inet_gro_complete,
- skb, 0);
+ skb, 0, 0);
break;
}
rcu_read_unlock();
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 2edc8b796a4e..7515e6bcbb7d 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -453,7 +453,7 @@ struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
}
EXPORT_SYMBOL(eth_gro_receive);

-int eth_gro_complete(struct sk_buff *skb, int nhoff)
+int eth_gro_complete(struct sk_buff *skb, int p_off, int nhoff)
{
struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
__be16 type = eh->h_proto;
@@ -467,7 +467,7 @@ int eth_gro_complete(struct sk_buff *skb, int nhoff)
if (ptype != NULL)
err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
ipv6_gro_complete, inet_gro_complete,
- skb, nhoff + sizeof(*eh));
+ skb, p_off, nhoff + sizeof(*eh));

return err;
}
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 5daebdcbca32..9334b563a88b 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1640,7 +1640,7 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
}
EXPORT_SYMBOL(inet_recv_error);

-int inet_gro_complete(struct sk_buff *skb, int nhoff)
+int inet_gro_complete(struct sk_buff *skb, int prior_off, int nhoff)
{
struct iphdr *iph = (struct iphdr *)(skb->data + nhoff);
const struct net_offload *ops;
@@ -1666,17 +1666,17 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff)
*/
err = INDIRECT_CALL_2(ops->callbacks.gro_complete,
tcp4_gro_complete, udp4_gro_complete,
- skb, nhoff + sizeof(*iph));
+ skb, nhoff, nhoff + sizeof(*iph));

out:
return err;
}

-static int ipip_gro_complete(struct sk_buff *skb, int nhoff)
+static int ipip_gro_complete(struct sk_buff *skb, int prior_off, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
- return inet_gro_complete(skb, nhoff);
+ return inet_gro_complete(skb, prior_off, nhoff);
}

int inet_ctl_sock_create(struct sock **sk, unsigned short family,
diff --git a/net/ipv4/fou_core.c b/net/ipv4/fou_core.c
index a8494f796dca..7cf214d0b96d 100644
--- a/net/ipv4/fou_core.c
+++ b/net/ipv4/fou_core.c
@@ -260,7 +260,7 @@ static struct sk_buff *fou_gro_receive(struct sock *sk,
}

static int fou_gro_complete(struct sock *sk, struct sk_buff *skb,
- int nhoff)
+ int p_off, int nhoff)
{
const struct net_offload __rcu **offloads;
u8 proto = fou_from_sock(sk)->protocol;
@@ -272,7 +272,7 @@ static int fou_gro_complete(struct sock *sk, struct sk_buff *skb,
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out;

- err = ops->callbacks.gro_complete(skb, nhoff);
+ err = ops->callbacks.gro_complete(skb, p_off, nhoff);

skb_set_inner_mac_header(skb, nhoff);

@@ -445,7 +445,8 @@ static struct sk_buff *gue_gro_receive(struct sock *sk,
return pp;
}

-static int gue_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
+static int gue_gro_complete(struct sock *sk, struct sk_buff *skb,
+ int p_off, int nhoff)
{
struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
const struct net_offload __rcu **offloads;
@@ -480,7 +481,7 @@ static int gue_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
if (WARN_ON(!ops || !ops->callbacks.gro_complete))
goto out;

- err = ops->callbacks.gro_complete(skb, nhoff + guehlen);
+ err = ops->callbacks.gro_complete(skb, p_off, nhoff + guehlen);

skb_set_inner_mac_header(skb, nhoff + guehlen);

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 5028c72d494a..d4520c3f7c09 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -233,7 +233,7 @@ static struct sk_buff *gre_gro_receive(struct list_head *head,
return pp;
}

-static int gre_gro_complete(struct sk_buff *skb, int nhoff)
+static int gre_gro_complete(struct sk_buff *skb, int p_off, int nhoff)
{
struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff);
struct packet_offload *ptype;
@@ -253,7 +253,8 @@ static int gre_gro_complete(struct sk_buff *skb, int nhoff)

ptype = gro_find_complete_by_type(type);
if (ptype)
- err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
+ err = ptype->callbacks.gro_complete(skb, p_off,
+ nhoff + grehlen);

skb_set_inner_mac_header(skb, nhoff + grehlen);

diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index b955ab3b236d..fde800179b2e 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -330,10 +330,11 @@ struct sk_buff *tcp4_gro_receive(struct list_head *head, struct sk_buff *skb)
return tcp_gro_receive(head, skb);
}

-INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
+INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int nhoff,
+ int thoff)
{
- const struct iphdr *iph = ip_hdr(skb);
- struct tcphdr *th = tcp_hdr(skb);
+ const struct iphdr *iph = (const struct iphdr *)(skb->data + nhoff);
+ struct tcphdr *th = (struct tcphdr *)(skb->data + thoff);

th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
iph->daddr, 0);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index a8acea17b4e5..70a6d174855f 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -532,9 +532,10 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
}

struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
+ int nhoff,
__be16 sport, __be16 dport)
{
- const struct iphdr *iph = ip_hdr(skb);
+ const struct iphdr *iph = (const struct iphdr *)(skb->data + nhoff);
struct net *net = dev_net(skb->dev);
int iif, sdif;

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 6c95d28d0c4a..cba615d52300 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -669,18 +669,19 @@ static int udp_gro_complete_segment(struct sk_buff *skb)
return 0;
}

-int udp_gro_complete(struct sk_buff *skb, int nhoff,
+int udp_gro_complete(struct sk_buff *skb, int nhoff, int thoff,
udp_lookup_t lookup)
{
- __be16 newlen = htons(skb->len - nhoff);
- struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
+ struct udphdr *uh = (struct udphdr *)(skb->data + thoff);
+ __be16 newlen = htons(skb->len - thoff);
struct sock *sk;
int err;

uh->len = newlen;

sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb,
- udp4_lib_lookup_skb, skb, uh->source, uh->dest);
+ udp4_lib_lookup_skb, skb, nhoff, uh->source,
+ uh->dest);
if (sk && udp_sk(sk)->gro_complete) {
skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
: SKB_GSO_UDP_TUNNEL;
@@ -694,8 +695,8 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
* functions to make them set up the inner offsets.
*/
skb->encapsulation = 1;
- err = udp_sk(sk)->gro_complete(sk, skb,
- nhoff + sizeof(struct udphdr));
+ err = udp_sk(sk)->gro_complete(sk, skb, nhoff,
+ thoff + sizeof(struct udphdr));
} else {
err = udp_gro_complete_segment(skb);
}
@@ -707,14 +708,15 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
}
EXPORT_SYMBOL(udp_gro_complete);

-INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
+INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff,
+ int thoff)
{
- const struct iphdr *iph = ip_hdr(skb);
- struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
+ const struct iphdr *iph = (const struct iphdr *)(skb->data + nhoff);
+ struct udphdr *uh = (struct udphdr *)(skb->data + thoff);

/* do fraglist only if there is no outer UDP encap (or we already processed it) */
if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
- uh->len = htons(skb->len - nhoff);
+ uh->len = htons(skb->len - thoff);

skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
@@ -731,10 +733,10 @@ INDIRECT_CALLABLE_SCOPE int udp4_gro_complete(struct sk_buff *skb, int nhoff)
}

if (uh->check)
- uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
+ uh->check = ~udp_v4_check(skb->len - thoff, iph->saddr,
iph->daddr, 0);

- return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
+ return udp_gro_complete(skb, nhoff, thoff, udp4_lib_lookup_skb);
}

static const struct net_offload udpv4_offload = {
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index cca64c7809be..e3a05b84c76a 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -346,12 +346,14 @@ static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
return inet_gro_receive(head, skb);
}

-INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
+INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb,
+ int p_off, int nhoff)
{
const struct net_offload *ops;
struct ipv6hdr *iph;
int err = -ENOSYS;
u32 payload_len;
+ int nhlen;

if (skb->encapsulation) {
skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
@@ -387,36 +389,36 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
iph->payload_len = htons(payload_len);
}

- nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
- if (WARN_ON(!ops || !ops->callbacks.gro_complete))
+ nhlen = sizeof(*iph) + ipv6_exthdrs_len(iph, &ops);
+ if (WARN_ON_ONCE(!ops || !ops->callbacks.gro_complete))
goto out;

err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete,
- udp6_gro_complete, skb, nhoff);
+ udp6_gro_complete, skb, nhoff, nhoff + nhlen);

out:
return err;
}

-static int sit_gro_complete(struct sk_buff *skb, int nhoff)
+static int sit_gro_complete(struct sk_buff *skb, int p_off, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
- return ipv6_gro_complete(skb, nhoff);
+ return ipv6_gro_complete(skb, p_off, nhoff);
}

-static int ip6ip6_gro_complete(struct sk_buff *skb, int nhoff)
+static int ip6ip6_gro_complete(struct sk_buff *skb, int p_off, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
- return ipv6_gro_complete(skb, nhoff);
+ return ipv6_gro_complete(skb, p_off, nhoff);
}

-static int ip4ip6_gro_complete(struct sk_buff *skb, int nhoff)
+static int ip4ip6_gro_complete(struct sk_buff *skb, int p_off, int nhoff)
{
skb->encapsulation = 1;
skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP6;
- return inet_gro_complete(skb, nhoff);
+ return inet_gro_complete(skb, p_off, nhoff);
}

static struct packet_offload ipv6_packet_offload __read_mostly = {
diff --git a/net/ipv6/tcpv6_offload.c b/net/ipv6/tcpv6_offload.c
index bf0c957e4b5e..5043d2ff34eb 100644
--- a/net/ipv6/tcpv6_offload.c
+++ b/net/ipv6/tcpv6_offload.c
@@ -27,10 +27,11 @@ struct sk_buff *tcp6_gro_receive(struct list_head *head, struct sk_buff *skb)
return tcp_gro_receive(head, skb);
}

-INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb, int thoff)
+INDIRECT_CALLABLE_SCOPE int tcp6_gro_complete(struct sk_buff *skb,
+ int nhoff, int thoff)
{
- const struct ipv6hdr *iph = ipv6_hdr(skb);
- struct tcphdr *th = tcp_hdr(skb);
+ const struct ipv6hdr *iph = (const struct ipv6hdr *)(skb->data + nhoff);
+ struct tcphdr *th = (struct tcphdr *)(skb->data + thoff);

th->check = ~tcp_v6_check(skb->len - thoff, &iph->saddr,
&iph->daddr, 0);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 3f2249b4cd5f..400243c89d82 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -273,9 +273,10 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
}

struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
+ int nhoff,
__be16 sport, __be16 dport)
{
- const struct ipv6hdr *iph = ipv6_hdr(skb);
+ const struct ipv6hdr *iph = (const struct ipv6hdr *)(skb->data + nhoff);
struct net *net = dev_net(skb->dev);
int iif, sdif;

diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 6b95ba241ebe..f930efd27180 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -162,14 +162,15 @@ struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb)
return NULL;
}

-INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
+INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff,
+ int thoff)
{
- const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
- struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
+ const struct ipv6hdr *ipv6h = (const struct ipv6hdr *)(skb->data + nhoff);
+ struct udphdr *uh = (struct udphdr *)(skb->data + thoff);

/* do fraglist only if there is no outer UDP encap (or we already processed it) */
if (NAPI_GRO_CB(skb)->is_flist && !NAPI_GRO_CB(skb)->encap_mark) {
- uh->len = htons(skb->len - nhoff);
+ uh->len = htons(skb->len - thoff);

skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
@@ -186,10 +187,10 @@ INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff)
}

if (uh->check)
- uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
+ uh->check = ~udp_v6_check(skb->len - thoff, &ipv6h->saddr,
&ipv6h->daddr, 0);

- return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
+ return udp_gro_complete(skb, nhoff, thoff, udp6_lib_lookup_skb);
}

static const struct net_offload udpv6_offload = {
--
2.36.1

2024-03-09 15:31:00

by Richard Gobert

[permalink] [raw]
Subject: [PATCH net-next v3 2/4] selftests/net: add local address bind in vxlan selftest

Add local address bind support to existing udpgro_fwd.sh vxlan selftest, to
ensure UDP socket lookup in GRO is working.

Signed-off-by: Richard Gobert <[email protected]>
---
tools/testing/selftests/net/udpgro_fwd.sh | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/udpgro_fwd.sh b/tools/testing/selftests/net/udpgro_fwd.sh
index 9cd5e885e91f..ed66365a2fc5 100755
--- a/tools/testing/selftests/net/udpgro_fwd.sh
+++ b/tools/testing/selftests/net/udpgro_fwd.sh
@@ -62,11 +62,13 @@ create_vxlan_endpoint() {
local -r bm_rem_addr=$3
local -r vxlan_dev=$4
local -r vxlan_id=$5
+ local -r bm_local_addr=$6
local -r vxlan_port=4789

ip -n $netns link set dev $bm_dev up
ip -n $netns link add dev $vxlan_dev type vxlan id $vxlan_id \
- dstport $vxlan_port remote $bm_rem_addr
+ dstport $vxlan_port local $bm_local_addr \
+ remote $bm_rem_addr
ip -n $netns link set dev $vxlan_dev up
}

@@ -77,11 +79,13 @@ create_vxlan_pair() {

for ns in $SRC $DST; do
# note that 3 - $SRC == $DST and 3 - $DST == $SRC
- create_vxlan_endpoint $BASE$ns veth$ns $BM_NET_V4$((3 - $ns)) vxlan$ns 4
+ create_vxlan_endpoint $BASE$ns veth$ns $BM_NET_V4$((3 - $ns)) \
+ vxlan$ns 4 $BM_NET_V4$ns
ip -n $BASE$ns addr add dev vxlan$ns $OL_NET_V4$ns/24
done
for ns in $SRC $DST; do
- create_vxlan_endpoint $BASE$ns veth$ns $BM_NET_V6$((3 - $ns)) vxlan6$ns 6
+ create_vxlan_endpoint $BASE$ns veth$ns $BM_NET_V6$((3 - $ns)) \
+ vxlan6$ns 6 $BM_NET_V6$ns
ip -n $BASE$ns addr add dev vxlan6$ns $OL_NET_V6$ns/24 nodad
done

--
2.36.1

2024-03-09 15:33:33

by Richard Gobert

[permalink] [raw]
Subject: [PATCH net-next v3 3/4] net: gro: add {inner_}network_offset to napi_gro_cb

This patch adds network_offset and inner_network_offset to napi_gro_cb, and
makes sure both are set correctly. In the common path there's only one
write (skb_gro_reset_offset).

Signed-off-by: Richard Gobert <[email protected]>
---
include/net/gro.h | 18 ++++++++++++++++--
net/8021q/vlan_core.c | 2 ++
net/core/gro.c | 1 +
net/ethernet/eth.c | 1 +
net/ipv4/af_inet.c | 5 +----
net/ipv4/gre_offload.c | 1 +
net/ipv6/ip6_offload.c | 8 ++++----
7 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/include/net/gro.h b/include/net/gro.h
index cb7282bf3d63..9d1389269509 100644
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -86,6 +86,15 @@ struct napi_gro_cb {

/* used to support CHECKSUM_COMPLETE for tunneling protocols */
__wsum csum;
+
+ /* L3 offsets */
+ union {
+ struct {
+ u16 network_offset;
+ u16 inner_network_offset;
+ };
+ u16 network_offsets[2];
+ };
};

#define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb)
@@ -171,12 +180,17 @@ static inline void *skb_gro_header(struct sk_buff *skb, unsigned int hlen,
return ptr;
}

+static inline int skb_gro_network_offset(const struct sk_buff *skb)
+{
+ return NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark];
+}
+
static inline void *skb_gro_network_header(const struct sk_buff *skb)
{
if (skb_gro_may_pull(skb, skb_gro_offset(skb)))
- return skb_gro_header_fast(skb, skb_network_offset(skb));
+ return skb_gro_header_fast(skb, skb_gro_network_offset(skb));

- return skb_network_header(skb);
+ return skb->data + skb_gro_network_offset(skb);
}

static inline __wsum inet_gro_compute_pseudo(const struct sk_buff *skb,
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 247704cf70af..355cafe23329 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -478,6 +478,8 @@ static struct sk_buff *vlan_gro_receive(struct list_head *head,
if (unlikely(!vhdr))
goto out;

+ NAPI_GRO_CB(skb)->network_offsets[NAPI_GRO_CB(skb)->encap_mark] = hlen;
+
type = vhdr->h_vlan_encapsulated_proto;

ptype = gro_find_receive_by_type(type);
diff --git a/net/core/gro.c b/net/core/gro.c
index 7da3df2c634f..2b42138f816c 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -373,6 +373,7 @@ static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff)
const skb_frag_t *frag0;
unsigned int headlen;

+ NAPI_GRO_CB(skb)->network_offset = 0;
NAPI_GRO_CB(skb)->data_offset = 0;
headlen = skb_headlen(skb);
NAPI_GRO_CB(skb)->frag0 = skb->data;
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 7515e6bcbb7d..e3eca605bcc7 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -441,6 +441,7 @@ struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)

skb_gro_pull(skb, sizeof(*eh));
skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
+ NAPI_GRO_CB(skb)->inner_network_offset = hlen;

pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
ipv6_gro_receive, inet_gro_receive,
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 9334b563a88b..c6bb21c27aee 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1567,10 +1567,6 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)

NAPI_GRO_CB(skb)->is_atomic = !!(iph->frag_off & htons(IP_DF));
NAPI_GRO_CB(skb)->flush |= flush;
- skb_set_network_header(skb, off);
- /* The above will be needed by the transport layer if there is one
- * immediately following this IP hdr.
- */

/* Note : No need to call skb_gro_postpull_rcsum() here,
* as we already checked checksum over ipv4 header was 0
@@ -1596,6 +1592,7 @@ static struct sk_buff *ipip_gro_receive(struct list_head *head,
}

NAPI_GRO_CB(skb)->encap_mark = 1;
+ NAPI_GRO_CB(skb)->inner_network_offset = skb_gro_offset(skb);

return inet_gro_receive(head, skb);
}
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index d4520c3f7c09..ae596285d78c 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -224,6 +224,7 @@ static struct sk_buff *gre_gro_receive(struct list_head *head,
/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
skb_gro_postpull_rcsum(skb, greh, grehlen);

+ NAPI_GRO_CB(skb)->inner_network_offset = hlen;
pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
flush = 0;

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index e3a05b84c76a..d9d3a6bed510 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -67,7 +67,7 @@ static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)
off += len;
}

- skb_gro_pull(skb, off - skb_network_offset(skb));
+ skb_gro_pull(skb, off - skb_gro_network_offset(skb));
return proto;
}

@@ -236,8 +236,6 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
if (unlikely(!iph))
goto out;

- skb_set_network_header(skb, off);
-
flush += ntohs(iph->payload_len) != skb->len - hlen;

proto = iph->nexthdr;
@@ -259,7 +257,7 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
NAPI_GRO_CB(skb)->proto = proto;

flush--;
- nlen = skb_network_header_len(skb);
+ nlen = skb_gro_offset(skb) - off;

list_for_each_entry(p, head, list) {
const struct ipv6hdr *iph2;
@@ -327,6 +325,7 @@ static struct sk_buff *sit_ip6ip6_gro_receive(struct list_head *head,
}

NAPI_GRO_CB(skb)->encap_mark = 1;
+ NAPI_GRO_CB(skb)->inner_network_offset = skb_gro_offset(skb);

return ipv6_gro_receive(head, skb);
}
@@ -342,6 +341,7 @@ static struct sk_buff *ip4ip6_gro_receive(struct list_head *head,
}

NAPI_GRO_CB(skb)->encap_mark = 1;
+ NAPI_GRO_CB(skb)->inner_network_offset = skb_gro_offset(skb);

return inet_gro_receive(head, skb);
}
--
2.36.1

2024-03-09 15:35:28

by Richard Gobert

[permalink] [raw]
Subject: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

{inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
iph->id, ...) against all packets in a loop. These flush checks are
relevant only to tcp flows, and as such they're used to determine whether
the packets can be merged later in tcp_gro_receive.

These checks are not relevant to UDP packets. Furthermore, they need to be
done only once in tcp_gro_receive and only against the found p skb, since
they only affect flush and not same_flow.

Levaraging the previous commit in the series, in which correct network
header offsets are saved for both outer and inner network headers -
allowing these checks to be done only once, in tcp_gro_receive. As a
result, NAPI_GRO_CB(p)->flush is not used at all. In addition - flush_id
checks are more declerative and contained in inet_gro_flush, thus removing
the need for flush_id in napi_gro_cb.

This results in less parsing code for UDP flows and non-loop flush tests
for TCP flows.

For example, running 40 IP/UDP netperf connections:
/super_netperf.sh 40 -H 1.1.1.2 -t UDP_STREAM -l 120

Running perf top for 90s we can see that relatively less time is spent
on inet_gro_receive when GRO is not coalescing UDP:

net-next:
1.26% [kernel] [k] inet_gro_receive

patch applied:
0.85% [kernel] [k] inet_gro_receive

udpgro_bench.sh single connection GRO improvement:
net-next:
0.76% [kernel] [k] inet_gro_receive

patch applied:
0.61% [kernel] [k] inet_gro_receive

Signed-off-by: Richard Gobert <[email protected]>
---
include/net/gro.h | 9 ++----
net/core/gro.c | 3 --
net/ipv4/af_inet.c | 36 ---------------------
net/ipv4/tcp_offload.c | 72 ++++++++++++++++++++++++++++++++++--------
net/ipv6/ip6_offload.c | 11 -------
5 files changed, 62 insertions(+), 69 deletions(-)

diff --git a/include/net/gro.h b/include/net/gro.h
index 9d1389269509..34e50f77f744 100644
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -35,15 +35,15 @@ struct napi_gro_cb {
/* This is non-zero if the packet cannot be merged with the new skb. */
u16 flush;

- /* Save the IP ID here and check when we get to the transport layer */
- u16 flush_id;
-
/* Number of segments aggregated. */
u16 count;

/* Used in ipv6_gro_receive() and foo-over-udp and esp-in-udp */
u16 proto;

+ /* used to support CHECKSUM_COMPLETE for tunneling protocols */
+ __wsum csum;
+
/* Used in napi_gro_cb::free */
#define NAPI_GRO_FREE 1
#define NAPI_GRO_FREE_STOLEN_HEAD 2
@@ -84,9 +84,6 @@ struct napi_gro_cb {
u8 is_flist:1;
);

- /* used to support CHECKSUM_COMPLETE for tunneling protocols */
- __wsum csum;
-
/* L3 offsets */
union {
struct {
diff --git a/net/core/gro.c b/net/core/gro.c
index 2b42138f816c..128d7b9c8dfb 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -332,8 +332,6 @@ static void gro_list_prepare(const struct list_head *head,
list_for_each_entry(p, head, list) {
unsigned long diffs;

- NAPI_GRO_CB(p)->flush = 0;
-
if (hash != skb_get_hash_raw(p)) {
NAPI_GRO_CB(p)->same_flow = 0;
continue;
@@ -473,7 +471,6 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
sizeof(u32))); /* Avoid slow unaligned acc */
*(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
NAPI_GRO_CB(skb)->flush = skb_has_frag_list(skb);
- NAPI_GRO_CB(skb)->is_atomic = 1;
NAPI_GRO_CB(skb)->count = 1;
if (unlikely(skb_is_gso(skb))) {
NAPI_GRO_CB(skb)->count = skb_shinfo(skb)->gso_segs;
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index c6bb21c27aee..5b74c6d2ed8b 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1512,7 +1512,6 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)

list_for_each_entry(p, head, list) {
struct iphdr *iph2;
- u16 flush_id;

if (!NAPI_GRO_CB(p)->same_flow)
continue;
@@ -1529,43 +1528,8 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)
NAPI_GRO_CB(p)->same_flow = 0;
continue;
}
-
- /* All fields must match except length and checksum. */
- NAPI_GRO_CB(p)->flush |=
- (iph->ttl ^ iph2->ttl) |
- (iph->tos ^ iph2->tos) |
- ((iph->frag_off ^ iph2->frag_off) & htons(IP_DF));
-
- NAPI_GRO_CB(p)->flush |= flush;
-
- /* We need to store of the IP ID check to be included later
- * when we can verify that this packet does in fact belong
- * to a given flow.
- */
- flush_id = (u16)(id - ntohs(iph2->id));
-
- /* This bit of code makes it much easier for us to identify
- * the cases where we are doing atomic vs non-atomic IP ID
- * checks. Specifically an atomic check can return IP ID
- * values 0 - 0xFFFF, while a non-atomic check can only
- * return 0 or 0xFFFF.
- */
- if (!NAPI_GRO_CB(p)->is_atomic ||
- !(iph->frag_off & htons(IP_DF))) {
- flush_id ^= NAPI_GRO_CB(p)->count;
- flush_id = flush_id ? 0xFFFF : 0;
- }
-
- /* If the previous IP ID value was based on an atomic
- * datagram we can overwrite the value and ignore it.
- */
- if (NAPI_GRO_CB(skb)->is_atomic)
- NAPI_GRO_CB(p)->flush_id = flush_id;
- else
- NAPI_GRO_CB(p)->flush_id |= flush_id;
}

- NAPI_GRO_CB(skb)->is_atomic = !!(iph->frag_off & htons(IP_DF));
NAPI_GRO_CB(skb)->flush |= flush;

/* Note : No need to call skb_gro_postpull_rcsum() here,
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index fde800179b2e..c165e72555e1 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -178,6 +178,55 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
return segs;
}

+static int inet_gro_flush(const struct iphdr *iph, const struct iphdr *iph2,
+ struct sk_buff *p, u32 outer)
+{
+ const u32 id = ntohl(*(__be32 *)&iph->id);
+ const u32 id2 = ntohl(*(__be32 *)&iph2->id);
+ const int flush_id = ntohs(id >> 16) - ntohs(id2 >> 16);
+ const u16 count = NAPI_GRO_CB(p)->count;
+ const u32 df = id & IP_DF;
+ u32 is_atomic;
+ int flush;
+
+ /* All fields must match except length and checksum. */
+ flush = (iph->ttl ^ iph2->ttl) | (iph->tos ^ iph2->tos) | (df ^ (id2 & IP_DF));
+
+ /* When we receive our second frame we can make a decision on if we
+ * continue this flow as an atomic flow with a fixed ID or if we use
+ * an incremdfenting ID.
+ */
+ if (count == 1) {
+ is_atomic = df && flush_id == 0;
+ NAPI_GRO_CB(p)->is_atomic = is_atomic;
+ } else {
+ is_atomic = df && NAPI_GRO_CB(p)->is_atomic;
+ }
+
+ /* Ignore outer IP ID value if based on atomic datagram. */
+ outer = (outer && df) - 1;
+ is_atomic--;
+
+ return flush | ((flush_id ^ (count & is_atomic)) & outer);
+}
+
+static int ipv6_gro_flush(const struct ipv6hdr *iph, const struct ipv6hdr *iph2)
+{
+ /* <Version:4><Traffic_Class:8><Flow_Label:20> */
+ __be32 first_word = *(__be32 *)iph ^ *(__be32 *)iph2;
+
+ /* Flush if Traffic Class fields are different. */
+ return (first_word & htonl(0x0FF00000)) |
+ (__force __be32)(iph->hop_limit ^ iph2->hop_limit);
+}
+
+static int gro_network_flush(const void *nh, const void *nh2,
+ struct sk_buff *p, u32 outer)
+{
+ return (((struct iphdr *)nh)->version == 6) ? ipv6_gro_flush(nh, nh2) :
+ inet_gro_flush(nh, nh2, p, outer);
+}
+
struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
{
struct sk_buff *pp = NULL;
@@ -190,6 +239,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
unsigned int mss = 1;
unsigned int hlen;
unsigned int off;
+ bool encap_mark;
int flush = 1;
int i;

@@ -232,9 +282,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
goto out_check_final;

found:
- /* Include the IP ID check below from the inner most IP hdr */
- flush = NAPI_GRO_CB(p)->flush;
- flush |= (__force int)(flags & TCP_FLAG_CWR);
+ flush = (__force int)(flags & TCP_FLAG_CWR);
flush |= (__force int)((flags ^ tcp_flag_word(th2)) &
~(TCP_FLAG_CWR | TCP_FLAG_FIN | TCP_FLAG_PSH));
flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
@@ -242,16 +290,14 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
flush |= *(u32 *)((u8 *)th + i) ^
*(u32 *)((u8 *)th2 + i);

- /* When we receive our second frame we can made a decision on if we
- * continue this flow as an atomic flow with a fixed ID or if we use
- * an incrementing ID.
- */
- if (NAPI_GRO_CB(p)->flush_id != 1 ||
- NAPI_GRO_CB(p)->count != 1 ||
- !NAPI_GRO_CB(p)->is_atomic)
- flush |= NAPI_GRO_CB(p)->flush_id;
- else
- NAPI_GRO_CB(p)->is_atomic = false;
+ encap_mark = NAPI_GRO_CB(skb)->encap_mark;
+ for (i = 0; i <= encap_mark; i++) {
+ const u16 diff = off - NAPI_GRO_CB(skb)->network_offsets[i];
+
+ flush |= gro_network_flush((void *)th - diff,
+ (void *)th2 - diff,
+ p, i != encap_mark);
+ }

mss = skb_shinfo(p)->gso_size;

diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index d9d3a6bed510..b1850c20d799 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -288,19 +288,8 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
nlen - sizeof(struct ipv6hdr)))
goto not_same_flow;
}
- /* flush if Traffic Class fields are different */
- NAPI_GRO_CB(p)->flush |= !!((first_word & htonl(0x0FF00000)) |
- (__force __be32)(iph->hop_limit ^ iph2->hop_limit));
- NAPI_GRO_CB(p)->flush |= flush;
-
- /* If the previous IP ID value was based on an atomic
- * datagram we can overwrite the value and ignore it.
- */
- if (NAPI_GRO_CB(skb)->is_atomic)
- NAPI_GRO_CB(p)->flush_id = 0;
}

- NAPI_GRO_CB(skb)->is_atomic = true;
NAPI_GRO_CB(skb)->flush |= flush;

skb_gro_postpull_rcsum(skb, iph, nlen);
--
2.36.1

2024-03-10 10:34:21

by Willem de Bruijn

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

Richard Gobert wrote:
> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
> iph->id, ...) against all packets in a loop. These flush checks are
> relevant only to tcp flows, and as such they're used to determine whether
> the packets can be merged later in tcp_gro_receive.
>
> These checks are not relevant to UDP packets.

These are network protocol coalescing invariants. Why would they be
limited to certain transport protocols only?

> Furthermore, they need to be
> done only once in tcp_gro_receive and only against the found p skb, since
> they only affect flush and not same_flow.
>
> Levaraging the previous commit in the series, in which correct network
> header offsets are saved for both outer and inner network headers -
> allowing these checks to be done only once, in tcp_gro_receive. As a
> result, NAPI_GRO_CB(p)->flush is not used at all. In addition - flush_id
> checks are more declerative and contained in inet_gro_flush, thus removing

declarative

> the need for flush_id in napi_gro_cb.
>
> Signed-off-by: Richard Gobert <[email protected]>
> ---
> +static int inet_gro_flush(const struct iphdr *iph, const struct iphdr *iph2,
> + struct sk_buff *p, u32 outer)
> +{
> + const u32 id = ntohl(*(__be32 *)&iph->id);
> + const u32 id2 = ntohl(*(__be32 *)&iph2->id);
> + const int flush_id = ntohs(id >> 16) - ntohs(id2 >> 16);
> + const u16 count = NAPI_GRO_CB(p)->count;
> + const u32 df = id & IP_DF;
> + u32 is_atomic;
> + int flush;
> +
> + /* All fields must match except length and checksum. */
> + flush = (iph->ttl ^ iph2->ttl) | (iph->tos ^ iph2->tos) | (df ^ (id2 & IP_DF));
> +
> + /* When we receive our second frame we can make a decision on if we
> + * continue this flow as an atomic flow with a fixed ID or if we use
> + * an incremdfenting ID.
> + */

Comment became garbled on move: incrementing

> + if (count == 1) {
> + is_atomic = df && flush_id == 0;
> + NAPI_GRO_CB(p)->is_atomic = is_atomic;
> + } else {
> + is_atomic = df && NAPI_GRO_CB(p)->is_atomic;
> + }
> +
> + /* Ignore outer IP ID value if based on atomic datagram. */
> + outer = (outer && df) - 1;
> + is_atomic--;
> +
> + return flush | ((flush_id ^ (count & is_atomic)) & outer);
> +}

2024-03-11 09:18:47

by Richard Gobert

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

Eric Dumazet wrote:
> On Sat, Mar 9, 2024 at 4:35 PM Richard Gobert <[email protected]> wrote:
>>
>> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
>> iph->id, ...) against all packets in a loop. These flush checks are
>> relevant only to tcp flows, and as such they're used to determine whether
>> the packets can be merged later in tcp_gro_receive.
>>
>> These checks are not relevant to UDP packets.
>
> I do not think this claim is true.
>
> Incoming packets -> GRO -> GSO -> forwarded packets
>
> The {GRO,GSO} step must be transparent, GRO is not LRO.

Sorry, I should rephrase myself. The patch preserves the
current logic in GRO. These L3 checks (ttl, flags, etc.) are written to
NAPI_GRO_CB(p)->{flush,flush_id}, and NAPI_GRO_CB(skb)->is_atomic - and
all of these are currently used only in tcp_gro_receive.

2024-03-11 09:22:17

by Richard Gobert

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

Willem de Bruijn wrote:
> Richard Gobert wrote:
>> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
>> iph->id, ...) against all packets in a loop. These flush checks are
>> relevant only to tcp flows, and as such they're used to determine whether
>> the packets can be merged later in tcp_gro_receive.
>>
>> These checks are not relevant to UDP packets.
>
> These are network protocol coalescing invariants. Why would they be
> limited to certain transport protocols only?

Thanks for the review, I'll fix the typos.
I replied to Eric's comment about the relevancy of these checks for UDP.

2024-03-11 12:14:30

by Willem de Bruijn

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

Richard Gobert wrote:
> Eric Dumazet wrote:
> > On Sat, Mar 9, 2024 at 4:35 PM Richard Gobert <[email protected]> wrote:
> >>
> >> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
> >> iph->id, ...) against all packets in a loop. These flush checks are
> >> relevant only to tcp flows, and as such they're used to determine whether
> >> the packets can be merged later in tcp_gro_receive.
> >>
> >> These checks are not relevant to UDP packets.
> >
> > I do not think this claim is true.
> >
> > Incoming packets -> GRO -> GSO -> forwarded packets
> >
> > The {GRO,GSO} step must be transparent, GRO is not LRO.
>
> Sorry, I should rephrase myself. The patch preserves the
> current logic in GRO. These L3 checks (ttl, flags, etc.) are written to
> NAPI_GRO_CB(p)->{flush,flush_id}, and NAPI_GRO_CB(skb)->is_atomic - and
> all of these are currently used only in tcp_gro_receive.

That was perhaps an oversight when adding UDP GRO?

Simply because the flush is determined in the innermost callback.

2024-03-11 13:08:47

by Richard Gobert

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

Willem de Bruijn wrote:
> Richard Gobert wrote:
>> Eric Dumazet wrote:
>>> On Sat, Mar 9, 2024 at 4:35 PM Richard Gobert <[email protected]> wrote:
>>>>
>>>> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
>>>> iph->id, ...) against all packets in a loop. These flush checks are
>>>> relevant only to tcp flows, and as such they're used to determine whether
>>>> the packets can be merged later in tcp_gro_receive.
>>>>
>>>> These checks are not relevant to UDP packets.
>>>
>>> I do not think this claim is true.
>>>
>>> Incoming packets -> GRO -> GSO -> forwarded packets
>>>
>>> The {GRO,GSO} step must be transparent, GRO is not LRO.
>>
>> Sorry, I should rephrase myself. The patch preserves the
>> current logic in GRO. These L3 checks (ttl, flags, etc.) are written to
>> NAPI_GRO_CB(p)->{flush,flush_id}, and NAPI_GRO_CB(skb)->is_atomic - and
>> all of these are currently used only in tcp_gro_receive.
>
> That was perhaps an oversight when adding UDP GRO?
>
> Simply because the flush is determined in the innermost callback.

It might have been an oversight. From what I have seen it's only relevant
to GRO's UDP fraglist path (it was added in 9fd1ff5d ("udp: Support UDP
fraglist GRO/GSO.")). That's the only UDP path that calls skb_gro_receive -
which may alter the forwarded packets and make GRO/GSO not transparent.

AFAIU NAPI_GRO_CB(p)->flush value is not overwritten in encapsulation - it
is determined by both outer and inner callbacks.

I tried to preserve the current behaviour in GRO - if we want to change
this behaviour I'll gladly do it, although I'd prefer to address it in a
different patch series. What do you think?

Thanks

2024-03-11 13:14:25

by Willem de Bruijn

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

Richard Gobert wrote:
> Willem de Bruijn wrote:
> > Richard Gobert wrote:
> >> Eric Dumazet wrote:
> >>> On Sat, Mar 9, 2024 at 4:35 PM Richard Gobert <[email protected]> wrote:
> >>>>
> >>>> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
> >>>> iph->id, ...) against all packets in a loop. These flush checks are
> >>>> relevant only to tcp flows, and as such they're used to determine whether
> >>>> the packets can be merged later in tcp_gro_receive.
> >>>>
> >>>> These checks are not relevant to UDP packets.
> >>>
> >>> I do not think this claim is true.
> >>>
> >>> Incoming packets -> GRO -> GSO -> forwarded packets
> >>>
> >>> The {GRO,GSO} step must be transparent, GRO is not LRO.
> >>
> >> Sorry, I should rephrase myself. The patch preserves the
> >> current logic in GRO. These L3 checks (ttl, flags, etc.) are written to
> >> NAPI_GRO_CB(p)->{flush,flush_id}, and NAPI_GRO_CB(skb)->is_atomic - and
> >> all of these are currently used only in tcp_gro_receive.
> >
> > That was perhaps an oversight when adding UDP GRO?
> >
> > Simply because the flush is determined in the innermost callback.
>
> It might have been an oversight. From what I have seen it's only relevant
> to GRO's UDP fraglist path (it was added in 9fd1ff5d ("udp: Support UDP
> fraglist GRO/GSO.")). That's the only UDP path that calls skb_gro_receive -
> which may alter the forwarded packets and make GRO/GSO not transparent.
>
> AFAIU NAPI_GRO_CB(p)->flush value is not overwritten in encapsulation - it
> is determined by both outer and inner callbacks.

Thanks for the context

> I tried to preserve the current behaviour in GRO - if we want to change
> this behaviour I'll gladly do it, although I'd prefer to address it in a
> different patch series. What do you think?

Yes, it's entirely reasonable to leave that out of this series.


2024-03-09 15:42:10

by Eric Dumazet

[permalink] [raw]
Subject: Re: [PATCH net-next v3 4/4] net: gro: move L3 flush checks to tcp_gro_receive

On Sat, Mar 9, 2024 at 4:35 PM Richard Gobert <richardbgobert@gmailcom> wrote:
>
> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
> iph->id, ...) against all packets in a loop. These flush checks are
> relevant only to tcp flows, and as such they're used to determine whether
> the packets can be merged later in tcp_gro_receive.
>
> These checks are not relevant to UDP packets.

I do not think this claim is true.

Incoming packets -> GRO -> GSO -> forwarded packets

The {GRO,GSO} step must be transparent, GRO is not LRO.