From 09f3d1a3a52c696208008618a67e2c7c3fb16d41 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 13 May 2022 11:34:01 -0700 Subject: ipv6/gso: remove temporary HBH/jumbo header ipv6 tcp and gro stacks will soon be able to build big TCP packets, with an added temporary Hop By Hop header. If GSO is involved for these large packets, we need to remove the temporary HBH header before segmentation happens. v2: perform HBH removal from ipv6_gso_segment() instead of skb_segment() (Alexander feedback) Signed-off-by: Eric Dumazet Acked-by: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv6/ip6_offload.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'net/ipv6') diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index c4fc03c1ac99..a6a6c1539c28 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; + int proto, nexthdr; struct frag_hdr *fptr; unsigned int payload_len; u8 *prevhdr; @@ -87,6 +87,28 @@ 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; + } nhoff = skb_network_header(skb) - skb_mac_header(skb); if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) goto out; -- cgit v1.2.3 From 81fbc812132cbc72a0f933b19bfd3a829bd946e4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 13 May 2022 11:34:02 -0700 Subject: ipv6/gro: insert temporary HBH/jumbo header 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 Acked-by: Alexander Duyck Signed-off-by: David S. Miller --- net/ipv6/ip6_offload.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index a6a6c1539c28..d12dba2dd535 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -342,15 +342,43 @@ 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)) -- cgit v1.2.3 From 80e425b613421911f89664663a7060216abcaed2 Mon Sep 17 00:00:00 2001 From: Coco Li Date: Fri, 13 May 2022 11:34:04 -0700 Subject: 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 Signed-off-by: Eric Dumazet Acked-by: Alexander Duyck Signed-off-by: David S. Miller --- include/linux/ipv6.h | 1 + net/ipv6/ip6_output.c | 22 ++++++++++++++++++++-- 2 files changed, 21 insertions(+), 2 deletions(-) (limited to 'net/ipv6') diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index ec5ca392eaa3..38c8203d52cb 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -145,6 +145,7 @@ struct inet6_skb_parm { #define IP6SKB_L3SLAVE 64 #define IP6SKB_JUMBOGRAM 128 #define IP6SKB_SEG6 256 +#define IP6SKB_FAKEJUMBO 512 }; #if defined(CONFIG_NET_L3_MASTER_DEV) 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); -- cgit v1.2.3