[PATCH v4 net-next 01/14] net: add netdev->tso_ipv6_max_size attribute

[Eric Dumazet <eric.dumazet@gmail.com>]

From: Eric Dumazet <edumazet@google.com>

Some NIC (or virtual devices) are LSOv2 compatible.

BIG TCP plans using the large LSOv2 feature for IPv6.

New netlink attribute IFLA_TSO_IPV6_MAX_SIZE is defined.

Drivers should use netif_set_tso_ipv6_max_size() to advertize their limit.

Unchanged drivers are not allowing big TSO packets to be sent.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/linux/netdevice.h          | 10 ++++++++++
 include/uapi/linux/if_link.h       |  1 +
 net/core/dev.c                     |  2 ++
 net/core/rtnetlink.c               |  3 +++
 tools/include/uapi/linux/if_link.h |  1 +
 5 files changed, 17 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 29a850a8d4604bb2ac43b582595f301aaa96a0bc..61db67222c47664c179b6a5d3b6f15fdf8a02bdd 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1951,6 +1951,7 @@ enum netdev_ml_priv_type {
  *	@dev_registered_tracker:	tracker for reference held while
  *					registered
  *	@offload_xstats_l3:	L3 HW stats for this netdevice.
+ *	@tso_ipv6_max_size:	Maximum size of IPv6 TSO packets (driver/NIC limit)
  *
  *	FIXME: cleanup struct net_device such that network protocol info
  *	moves out.
@@ -2289,6 +2290,7 @@ struct net_device {
 	netdevice_tracker	watchdog_dev_tracker;
 	netdevice_tracker	dev_registered_tracker;
 	struct rtnl_hw_stats64	*offload_xstats_l3;
+	unsigned int		tso_ipv6_max_size;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
@@ -4888,6 +4890,14 @@ static inline void netif_set_gro_max_size(struct net_device *dev,
 	WRITE_ONCE(dev->gro_max_size, size);
 }
 
+/* Used by drivers to give their hardware/firmware limit for LSOv2 packets */
+static inline void netif_set_tso_ipv6_max_size(struct net_device *dev,
+					       unsigned int size)
+{
+	dev->tso_ipv6_max_size = size;
+}
+
+
 static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol,
 					int pulled_hlen, u16 mac_offset,
 					int mac_len)
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index ddca20357e7e89b5f204b3117ff3838735535470..c8af031b692e52690a2760e9d79c9462185e2fc9 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -363,6 +363,7 @@ enum {
 	IFLA_PARENT_DEV_NAME,
 	IFLA_PARENT_DEV_BUS_NAME,
 	IFLA_GRO_MAX_SIZE,
+	IFLA_TSO_IPV6_MAX_SIZE,
 
 	__IFLA_MAX
 };
diff --git a/net/core/dev.c b/net/core/dev.c
index ba69ddf85af6b4543caa91f314caf54794a3a02a..de28f634c18a65d1948a96db5678d38e9c871b1f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10467,6 +10467,8 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	dev->gso_max_size = GSO_MAX_SIZE;
 	dev->gso_max_segs = GSO_MAX_SEGS;
 	dev->gro_max_size = GRO_MAX_SIZE;
+	dev->tso_ipv6_max_size = GSO_MAX_SIZE;
+
 	dev->upper_level = 1;
 	dev->lower_level = 1;
 #ifdef CONFIG_LOCKDEP
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a759f9e0a8476538fb41311113daed998a7193fd..ab51b18cdb5d46b87d4a11d2f66a68968ba737d6 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1027,6 +1027,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(4) /* IFLA_GSO_MAX_SEGS */
 	       + nla_total_size(4) /* IFLA_GSO_MAX_SIZE */
 	       + nla_total_size(4) /* IFLA_GRO_MAX_SIZE */
+	       + nla_total_size(4) /* IFLA_TSO_IPV6_MAX_SIZE */
 	       + nla_total_size(1) /* IFLA_OPERSTATE */
 	       + nla_total_size(1) /* IFLA_LINKMODE */
 	       + nla_total_size(4) /* IFLA_CARRIER_CHANGES */
@@ -1732,6 +1733,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
 	    nla_put_u32(skb, IFLA_GSO_MAX_SEGS, dev->gso_max_segs) ||
 	    nla_put_u32(skb, IFLA_GSO_MAX_SIZE, dev->gso_max_size) ||
 	    nla_put_u32(skb, IFLA_GRO_MAX_SIZE, dev->gro_max_size) ||
+	    nla_put_u32(skb, IFLA_TSO_IPV6_MAX_SIZE, dev->tso_ipv6_max_size) ||
 #ifdef CONFIG_RPS
 	    nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
 #endif
@@ -1885,6 +1887,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_NEW_IFINDEX]	= NLA_POLICY_MIN(NLA_S32, 1),
 	[IFLA_PARENT_DEV_NAME]	= { .type = NLA_NUL_STRING },
 	[IFLA_GRO_MAX_SIZE]	= { .type = NLA_U32 },
+	[IFLA_TSO_IPV6_MAX_SIZE]	= { .type = NLA_U32 },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index e1ba2d51b717b7ac7f06e94ac9791cf4c8a5ab6f..441615c39f0a24eeeb6e27b4ca88031bcc234cf8 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -348,6 +348,7 @@ enum {
 	IFLA_PARENT_DEV_NAME,
 	IFLA_PARENT_DEV_BUS_NAME,
 	IFLA_GRO_MAX_SIZE,
+	IFLA_TSO_IPV6_MAX_SIZE,
 
 	__IFLA_MAX
 };
-- 
2.35.1.616.g0bdcbb4464-goog