[PATCH v6 net-next 08/13] net: allow gro_max_size to exceed 65536
From: Eric Dumazet <hidden>
Date: 2022-05-10 03:32:59
Subsystem:
mellanox ethernet driver (mlx5e), mellanox mlx5 core vpi driver, networking drivers, networking [general], networking [ipv4/ipv6], the rest · Maintainers:
Saeed Mahameed, Tariq Toukan, Mark Bloch, Leon Romanovsky, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Alexander Duyck <alexanderduyck@fb.com> Allow the gro_max_size to exceed a value larger than 65536. There weren't really any external limitations that prevented this other than the fact that IPv4 only supports a 16 bit length field. Since we have the option of adding a hop-by-hop header for IPv6 we can allow IPv6 to exceed this value and for IPv4 and non-TCP flows we can cap things at 65536 via a constant rather than relying on gro_max_size. [edumazet] limit GRO_MAX_SIZE to (8 * 65535) to avoid overflows. Signed-off-by: Alexander Duyck <alexanderduyck@fb.com> Signed-off-by: Eric Dumazet <edumazet@google.com> --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 2 +- include/linux/netdevice.h | 6 +++++- include/net/ipv6.h | 2 +- net/core/dev.c | 2 +- net/core/gro.c | 8 ++++++++ net/core/rtnetlink.c | 8 -------- 6 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 838870bc6dbd6e3a3d8c9443ff4675a0e411006b..24de37b79f5a917b304c011fcebcd09748ee5c6a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c@@ -2038,7 +2038,7 @@ mlx5e_hw_gro_skb_has_enough_space(struct sk_buff *skb, u16 data_bcnt) { int nr_frags = skb_shinfo(skb)->nr_frags; - return PAGE_SIZE * nr_frags + data_bcnt <= GRO_MAX_SIZE; + return PAGE_SIZE * nr_frags + data_bcnt <= GRO_LEGACY_MAX_SIZE; } static void
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 673c444aae874428b117df45dffcaf702ac72a47..69743188f639c5afd20f06a5e301edca00aedaef 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -2151,7 +2151,11 @@ struct net_device { struct bpf_prog __rcu *xdp_prog; unsigned long gro_flush_timeout; int napi_defer_hard_irqs; -#define GRO_MAX_SIZE 65536 +#define GRO_LEGACY_MAX_SIZE 65536u +/* TCP minimal MSS is 8 (TCP_MIN_GSO_SIZE), + * and shinfo->gso_segs is a 16bit field. + */ +#define GRO_MAX_SIZE (8 * 65535u) unsigned int gro_max_size; rx_handler_func_t __rcu *rx_handler; void __rcu *rx_handler_data;
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index b6df0314aa02dd1c4094620145ccb24da7195b2b..5b38bf1a586b9da55f43db30d140d364a70f6c11 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h@@ -477,7 +477,7 @@ static inline int ipv6_has_hopopt_jumbo(const struct sk_buff *skb) const struct hop_jumbo_hdr *jhdr; const struct ipv6hdr *nhdr; - if (likely(skb->len <= GRO_MAX_SIZE)) + if (likely(skb->len <= GRO_LEGACY_MAX_SIZE)) return 0; if (skb->protocol != htons(ETH_P_IPV6))
diff --git a/net/core/dev.c b/net/core/dev.c
index 68b76b45a5ac5f2ea705bd3db5d1732b79034609..4be3695846520af18a687cdcaa70c5f327ba94e8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -10605,7 +10605,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, dev->gso_max_size = GSO_LEGACY_MAX_SIZE; dev->gso_max_segs = GSO_MAX_SEGS; - dev->gro_max_size = GRO_MAX_SIZE; + dev->gro_max_size = GRO_LEGACY_MAX_SIZE; dev->tso_max_size = TSO_LEGACY_MAX_SIZE; dev->tso_max_segs = TSO_MAX_SEGS; dev->upper_level = 1;
diff --git a/net/core/gro.c b/net/core/gro.c
index 78110edf5d4b36d2fa6f8a2676096efe0112aa0e..b4190eb084672fb4f2be8b437eccb4e8507ff63f 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c@@ -167,6 +167,14 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush)) return -E2BIG; + if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { + if (p->protocol != htons(ETH_P_IPV6) || + skb_headroom(p) < sizeof(struct hop_jumbo_hdr) || + ipv6_hdr(p)->nexthdr != IPPROTO_TCP || + p->encapsulation) + return -E2BIG; + } + lp = NAPI_GRO_CB(p)->last; pinfo = skb_shinfo(lp);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 823db8999a2c1d5959042393783492dbecf1352c..5d7d7fe1e63a972bbcbd5eed1404b2643c74cfcb 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -2347,14 +2347,6 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[], } } - if (tb[IFLA_GRO_MAX_SIZE]) { - u32 gro_max_size = nla_get_u32(tb[IFLA_GRO_MAX_SIZE]); - - if (gro_max_size > GRO_MAX_SIZE) { - NL_SET_ERR_MSG(extack, "too big gro_max_size"); - return -EINVAL; - } - } return 0; }
--
2.36.0.512.ge40c2bad7a-goog