Commit 0fe79f28 authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
Browse files

net: allow gro_max_size to exceed 65536 



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: default avatarAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 81fbc812

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

+1 −1
Original line number Diff line number Diff line
@@ -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

include/linux/netdevice.h

+5 −1
Original line number Diff line number Diff line
@@ -2161,7 +2161,11 @@ 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;

include/net/ipv6.h

+1 −1
Original line number Diff line number Diff line
@@ -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))

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -10598,7 +10598,7 @@ 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;

net/core/gro.c

+8 −0
Original line number Diff line number Diff line
@@ -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);