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authorCoco Li <lixiaoyan@google.com>2022-05-13 11:34:04 -0700
committerDavid S. Miller <davem@davemloft.net>2022-05-16 10:18:56 +0100
commit80e425b613421911f89664663a7060216abcaed2 (patch)
tree6e31830a826091a89ce2bc08e396e9a9851f1116 /net/ipv6
parent0fe79f28bfaf73b66b7b1562d2468f94aa03bd12 (diff)
ipv6: Add hop-by-hop header to jumbograms in ip6_output
Instead of simply forcing a 0 payload_len in IPv6 header, implement RFC 2675 and insert a custom extension header. Note that only TCP stack is currently potentially generating jumbograms, and that this extension header is purely local, it wont be sent on a physical link. This is needed so that packet capture (tcpdump and friends) can properly dissect these large packets. Signed-off-by: Coco Li <lixiaoyan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Alexander Duyck <alexanderduyck@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_output.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index afa5bd4ad167..4081b12a01ff 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -182,7 +182,9 @@ static int __ip6_finish_output(struct net *net, struct sock *sk, struct sk_buff
#endif
mtu = ip6_skb_dst_mtu(skb);
- if (skb_is_gso(skb) && !skb_gso_validate_network_len(skb, mtu))
+ if (skb_is_gso(skb) &&
+ !(IP6CB(skb)->flags & IP6SKB_FAKEJUMBO) &&
+ !skb_gso_validate_network_len(skb, mtu))
return ip6_finish_output_gso_slowpath_drop(net, sk, skb, mtu);
if ((skb->len > mtu && !skb_is_gso(skb)) ||
@@ -252,6 +254,8 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
struct dst_entry *dst = skb_dst(skb);
struct net_device *dev = dst->dev;
struct inet6_dev *idev = ip6_dst_idev(dst);
+ struct hop_jumbo_hdr *hop_jumbo;
+ int hoplen = sizeof(*hop_jumbo);
unsigned int head_room;
struct ipv6hdr *hdr;
u8 proto = fl6->flowi6_proto;
@@ -259,7 +263,7 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
int hlimit = -1;
u32 mtu;
- head_room = sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dev);
+ head_room = sizeof(struct ipv6hdr) + hoplen + LL_RESERVED_SPACE(dev);
if (opt)
head_room += opt->opt_nflen + opt->opt_flen;
@@ -282,6 +286,20 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
&fl6->saddr);
}
+ if (unlikely(seg_len > IPV6_MAXPLEN)) {
+ hop_jumbo = skb_push(skb, hoplen);
+
+ hop_jumbo->nexthdr = proto;
+ hop_jumbo->hdrlen = 0;
+ hop_jumbo->tlv_type = IPV6_TLV_JUMBO;
+ hop_jumbo->tlv_len = 4;
+ hop_jumbo->jumbo_payload_len = htonl(seg_len + hoplen);
+
+ proto = IPPROTO_HOPOPTS;
+ seg_len = 0;
+ IP6CB(skb)->flags |= IP6SKB_FAKEJUMBO;
+ }
+
skb_push(skb, sizeof(struct ipv6hdr));
skb_reset_network_header(skb);
hdr = ipv6_hdr(skb);