Messages in this thread |  | | From | Michael Chan <> | Date | Sun, 4 Dec 2022 18:23:35 -0800 | Subject | Re: [RFC net-next v4 1/2] IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver |
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On Fri, Dec 2, 2022 at 2:12 PM Coco Li <lixiaoyan@google.com> wrote: > > IPv6/TCP and GRO stacks can build big TCP packets with an added > temporary Hop By Hop header. > > Is GSO is not involved, then the temporary header needs to be removed in > the driver. This patch provides a generic helper for drivers that need > to modify their headers in place. > > Signed-off-by: Coco Li <lixiaoyan@google.com> > --- > include/net/ipv6.h | 35 +++++++++++++++++++++++++++++++++++ > net/ipv6/ip6_offload.c | 27 ++++----------------------- > 2 files changed, 39 insertions(+), 23 deletions(-) > > diff --git a/include/net/ipv6.h b/include/net/ipv6.h > index d383c895592a..08adec74f067 100644 > --- a/include/net/ipv6.h > +++ b/include/net/ipv6.h > @@ -500,6 +500,41 @@ static inline int ipv6_has_hopopt_jumbo(const struct sk_buff *skb) > return jhdr->nexthdr; > } > > +/* Return 0 if HBH header is successfully removed > + * Or if HBH removal is unnecessary (packet is not big TCP) > + * Return error to indicate dropping the packet > + */ > +static inline int ipv6_hopopt_jumbo_remove(struct sk_buff *skb) > +{ > + const int hophdr_len = sizeof(struct hop_jumbo_hdr); > + int nexthdr = ipv6_has_hopopt_jumbo(skb); > + struct ipv6hdr *h6; > + > + if (!nexthdr) > + return 0; > + > + if (skb_cow_head(skb, 0)) > + return -1; > + > + /* Remove the HBH header. > + * Layout: [Ethernet header][IPv6 header][HBH][L4 Header] > + */ > + memmove(skb_mac_header(skb) + hophdr_len, skb_mac_header(skb), > + skb_network_header(skb) - skb_mac_header(skb) + > + sizeof(struct ipv6hdr)); > + > + if (unlikely(!pskb_may_pull(skb, hophdr_len))) > + return -1; > +
This version doesn't seem to work. I think you need to add hophdr_len to skb->data and subtract it from skb->len.
> + skb->network_header += hophdr_len; > + skb->mac_header += hophdr_len; > + > + h6 = ipv6_hdr(skb); > + h6->nexthdr = nexthdr; > + > + return 0; > +} > + > static inline bool ipv6_accept_ra(struct inet6_dev *idev) > { > /* If forwarding is enabled, RA are not accepted unless the special > diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c > index 3ee345672849..00dc2e3b0184 100644 > --- a/net/ipv6/ip6_offload.c > +++ b/net/ipv6/ip6_offload.c > @@ -77,7 +77,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, > struct sk_buff *segs = ERR_PTR(-EINVAL); > struct ipv6hdr *ipv6h; > const struct net_offload *ops; > - int proto, nexthdr; > + int proto, err; > struct frag_hdr *fptr; > unsigned int payload_len; > u8 *prevhdr; > @@ -87,28 +87,9 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, > bool gso_partial; > > skb_reset_network_header(skb); > - nexthdr = ipv6_has_hopopt_jumbo(skb); > - if (nexthdr) { > - const int hophdr_len = sizeof(struct hop_jumbo_hdr); > - int err; > - > - err = skb_cow_head(skb, 0); > - if (err < 0) > - return ERR_PTR(err); > - > - /* remove the HBH header. > - * Layout: [Ethernet header][IPv6 header][HBH][TCP header] > - */ > - memmove(skb_mac_header(skb) + hophdr_len, > - skb_mac_header(skb), > - ETH_HLEN + sizeof(struct ipv6hdr)); > - skb->data += hophdr_len; > - skb->len -= hophdr_len; > - skb->network_header += hophdr_len; > - skb->mac_header += hophdr_len; > - ipv6h = (struct ipv6hdr *)skb->data; > - ipv6h->nexthdr = nexthdr; > - } > + err = ipv6_hopopt_jumbo_remove(skb); > + if (err) > + return ERR_PTR(err); > nhoff = skb_network_header(skb) - skb_mac_header(skb); > if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) > goto out; > -- > 2.39.0.rc0.267.gcb52ba06e7-goog > [unhandled content-type:application/pkcs7-signature] |  |