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Commit 3347c960 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv4: gso: make inet_gso_segment() stackable 



In order to support GSO on IPIP, we need to make
inet_gso_segment() stackable.

It should not assume network header starts right after mac
header.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2d26f0a3

include/linux/skbuff.h

+5 −2
Original line number Diff line number Diff line
@@ -2722,9 +2722,12 @@ static inline struct sec_path *skb_sec_path(struct sk_buff *skb) 
/* Keeps track of mac header offset relative to skb->head.

 * It is useful for TSO of Tunneling protocol. e.g. GRE.

 * For non-tunnel skb it points to skb_mac_header() and for

 * tunnel skb it points to outer mac header. */

 * tunnel skb it points to outer mac header.

 * Keeps track of level of encapsulation of network headers.

 */

struct skb_gso_cb {

	int	mac_offset;

	int	encap_level;

};

#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)

net/core/dev.c

+2 −0
Original line number Diff line number Diff line
@@ -2377,6 +2377,8 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb, 
	}



	SKB_GSO_CB(skb)->mac_offset = skb_headroom(skb);

	SKB_GSO_CB(skb)->encap_level = 0;



	skb_reset_mac_header(skb);

	skb_reset_mac_len(skb);

net/ipv4/af_inet.c

+18 −7
Original line number Diff line number Diff line
@@ -1277,12 +1277,13 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, 
{

	struct sk_buff *segs = ERR_PTR(-EINVAL);

	const struct net_offload *ops;

	unsigned int offset = 0;

	struct iphdr *iph;

	bool tunnel;

	int proto;

	int nhoff;

	int ihl;

	int id;

	unsigned int offset = 0;

	bool tunnel;



	if (unlikely(skb_shinfo(skb)->gso_type &

		     ~(SKB_GSO_TCPV4 |
@@ -1296,6 +1297,8 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, 
		       0)))

		goto out;



	skb_reset_network_header(skb);

	nhoff = skb_network_header(skb) - skb_mac_header(skb);

	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))

		goto out;
@@ -1312,7 +1315,10 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, 
		goto out;

	__skb_pull(skb, ihl);



	tunnel = !!skb->encapsulation;

	tunnel = SKB_GSO_CB(skb)->encap_level > 0;

	if (tunnel)

		features = skb->dev->hw_enc_features & netif_skb_features(skb);

	SKB_GSO_CB(skb)->encap_level += ihl;



	skb_reset_transport_header(skb);
@@ -1327,18 +1333,23 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, 


	skb = segs;

	do {

		iph = ip_hdr(skb);

		iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);

		if (!tunnel && proto == IPPROTO_UDP) {

			iph->id = htons(id);

			iph->frag_off = htons(offset >> 3);

			if (skb->next != NULL)

				iph->frag_off |= htons(IP_MF);

			offset += (skb->len - skb->mac_len - iph->ihl * 4);

			offset += skb->len - nhoff - ihl;

		} else  {

			iph->id = htons(id++);

		}

		iph->tot_len = htons(skb->len - skb->mac_len);

		iph->tot_len = htons(skb->len - nhoff);

		ip_send_check(iph);

		if (tunnel) {

			skb_reset_inner_headers(skb);

			skb->encapsulation = 1;

		}

		skb->network_header = (u8 *)iph - skb->head;

	} while ((skb = skb->next));



out: