| Message ID | 20220203015140.3022854-7-eric.dumazet@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | tcp: BIG TCP implementation | expand |
On Wed, 2022-02-02 at 17:51 -0800, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > Following patch will add GRO_IPV6_MAX_SIZE, allowing gro to build > BIG TCP ipv6 packets (bigger than 64K). > > This patch changes ipv6_gro_complete() to insert a HBH/jumbo header > so that resulting packet can go through IPv6/TCP stacks. > > Signed-off-by: Eric Dumazet <edumazet@google.com> > --- > net/ipv6/ip6_offload.c | 32 ++++++++++++++++++++++++++++++-- > 1 file changed, 30 insertions(+), 2 deletions(-) > > diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c > index d37a79a8554e92a1dcaa6fd023cafe2114841ece..dac6f60436e167a3d979fef02f25fc039c6ed37d 100644 > --- a/net/ipv6/ip6_offload.c > +++ b/net/ipv6/ip6_offload.c > @@ -318,15 +318,43 @@ static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, > INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) > { > const struct net_offload *ops; > - struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); > + struct ipv6hdr *iph; > int err = -ENOSYS; > + u32 payload_len; > > if (skb->encapsulation) { > skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); > skb_set_inner_network_header(skb, nhoff); > } > > - iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); > + payload_len = skb->len - nhoff - sizeof(*iph); > + if (unlikely(payload_len > IPV6_MAXPLEN)) { > + struct hop_jumbo_hdr *hop_jumbo; > + int hoplen = sizeof(*hop_jumbo); > + > + /* Move network header left */ > + memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb), > + skb->transport_header - skb->mac_header); I was wondering if we should check for enough headroom and what about TCP over UDP tunnel, then I read the next patch ;) I think a comment here referring to the constraint enforced by skb_gro_receive() could help, or perhaps squashing the 2 patches?!? Thanks! Paolo
On Thu, Feb 3, 2022 at 1:20 AM Paolo Abeni <pabeni@redhat.com> wrote: > > On Wed, 2022-02-02 at 17:51 -0800, Eric Dumazet wrote: > > From: Eric Dumazet <edumazet@google.com> > > > > Following patch will add GRO_IPV6_MAX_SIZE, allowing gro to build > > BIG TCP ipv6 packets (bigger than 64K). > > > > This patch changes ipv6_gro_complete() to insert a HBH/jumbo header > > so that resulting packet can go through IPv6/TCP stacks. > > > > Signed-off-by: Eric Dumazet <edumazet@google.com> > > --- > > net/ipv6/ip6_offload.c | 32 ++++++++++++++++++++++++++++++-- > > 1 file changed, 30 insertions(+), 2 deletions(-) > > > > diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c > > index d37a79a8554e92a1dcaa6fd023cafe2114841ece..dac6f60436e167a3d979fef02f25fc039c6ed37d 100644 > > --- a/net/ipv6/ip6_offload.c > > +++ b/net/ipv6/ip6_offload.c > > @@ -318,15 +318,43 @@ static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, > > INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) > > { > > const struct net_offload *ops; > > - struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); > > + struct ipv6hdr *iph; > > int err = -ENOSYS; > > + u32 payload_len; > > > > if (skb->encapsulation) { > > skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); > > skb_set_inner_network_header(skb, nhoff); > > } > > > > - iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); > > + payload_len = skb->len - nhoff - sizeof(*iph); > > + if (unlikely(payload_len > IPV6_MAXPLEN)) { > > + struct hop_jumbo_hdr *hop_jumbo; > > + int hoplen = sizeof(*hop_jumbo); > > + > > + /* Move network header left */ > > + memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb), > > + skb->transport_header - skb->mac_header); > > I was wondering if we should check for enough headroom and what about > TCP over UDP tunnel, then I read the next patch ;) The check about headroom is provided in the following patch (ipv6: add GRO_IPV6_MAX_SIZE), which allows GRO stack to build packets bigger than 64KB, if drivers provided enough headroom (8 bytes). They usually provide NET_SKB_PAD (64 bytes or more) Before the next patch, this code is dead. Also current patch set does not cook BIG TCP packets for tunneled traffic (look at skb_gro_receive() changes in following patch) > > I think a comment here referring to the constraint enforced by > skb_gro_receive() could help, or perhaps squashing the 2 patches?!? Well no, we spent time making small patches to ease review, and these patches have different authors anyway. > > Thanks! > > Paolo >
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index d37a79a8554e92a1dcaa6fd023cafe2114841ece..dac6f60436e167a3d979fef02f25fc039c6ed37d 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -318,15 +318,43 @@ static struct sk_buff *ip4ip6_gro_receive(struct list_head *head, INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) { const struct net_offload *ops; - struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); + struct ipv6hdr *iph; int err = -ENOSYS; + u32 payload_len; if (skb->encapsulation) { skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6)); skb_set_inner_network_header(skb, nhoff); } - iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); + payload_len = skb->len - nhoff - sizeof(*iph); + if (unlikely(payload_len > IPV6_MAXPLEN)) { + struct hop_jumbo_hdr *hop_jumbo; + int hoplen = sizeof(*hop_jumbo); + + /* Move network header left */ + memmove(skb_mac_header(skb) - hoplen, skb_mac_header(skb), + skb->transport_header - skb->mac_header); + skb->data -= hoplen; + skb->len += hoplen; + skb->mac_header -= hoplen; + skb->network_header -= hoplen; + iph = (struct ipv6hdr *)(skb->data + nhoff); + hop_jumbo = (struct hop_jumbo_hdr *)(iph + 1); + + /* Build hop-by-hop options */ + hop_jumbo->nexthdr = iph->nexthdr; + hop_jumbo->hdrlen = 0; + hop_jumbo->tlv_type = IPV6_TLV_JUMBO; + hop_jumbo->tlv_len = 4; + hop_jumbo->jumbo_payload_len = htonl(payload_len + hoplen); + + iph->nexthdr = NEXTHDR_HOP; + iph->payload_len = 0; + } else { + iph = (struct ipv6hdr *)(skb->data + nhoff); + iph->payload_len = htons(payload_len); + } nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); if (WARN_ON(!ops || !ops->callbacks.gro_complete))