net: add support for ipv4 big tcp
Similar to Eric's IPv6 BIG TCP, this patch is to enable IPv4 BIG TCP. Firstly, allow sk->sk_gso_max_size to be set to a value greater than GSO_LEGACY_MAX_SIZE by not trimming gso_max_size in sk_trim_gso_size() for IPv4 TCP sockets. Then on TX path, set IP header tot_len to 0 when skb->len > IP_MAX_MTU in __ip_local_out() to allow to send BIG TCP packets, and this implies that skb->len is the length of a IPv4 packet; On RX path, use skb->len as the length of the IPv4 packet when the IP header tot_len is 0 and skb->len > IP_MAX_MTU in ip_rcv_core(). As the API iph_set_totlen() and skb_ip_totlen() are used in __ip_local_out() and ip_rcv_core(), we only need to update these APIs. Also in GRO receive, add the check for ETH_P_IP/IPPROTO_TCP, and allows the merged packet size >= GRO_LEGACY_MAX_SIZE in skb_gro_receive(). In GRO complete, set IP header tot_len to 0 when the merged packet size greater than IP_MAX_MTU in iph_set_totlen() so that it can be processed on RX path. Note that by checking skb_is_gso_tcp() in API iph_totlen(), it makes this implementation safe to use iph->len == 0 indicates IPv4 BIG TCP packets. Signed-off-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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@ -162,16 +162,18 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb)
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struct sk_buff *lp;
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int segs;
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/* pairs with WRITE_ONCE() in netif_set_gro_max_size() */
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gro_max_size = READ_ONCE(p->dev->gro_max_size);
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/* pairs with WRITE_ONCE() in netif_set_gro(_ipv4)_max_size() */
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gro_max_size = p->protocol == htons(ETH_P_IPV6) ?
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READ_ONCE(p->dev->gro_max_size) :
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READ_ONCE(p->dev->gro_ipv4_max_size);
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if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush))
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return -E2BIG;
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if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) {
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if (p->protocol != htons(ETH_P_IPV6) ||
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skb_headroom(p) < sizeof(struct hop_jumbo_hdr) ||
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ipv6_hdr(p)->nexthdr != IPPROTO_TCP ||
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if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP ||
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(p->protocol == htons(ETH_P_IPV6) &&
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skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) ||
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p->encapsulation)
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return -E2BIG;
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}
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@ -2373,17 +2373,22 @@ void sk_free_unlock_clone(struct sock *sk)
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}
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EXPORT_SYMBOL_GPL(sk_free_unlock_clone);
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static void sk_trim_gso_size(struct sock *sk)
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static u32 sk_dst_gso_max_size(struct sock *sk, struct dst_entry *dst)
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{
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if (sk->sk_gso_max_size <= GSO_LEGACY_MAX_SIZE)
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return;
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bool is_ipv6 = false;
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u32 max_size;
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#if IS_ENABLED(CONFIG_IPV6)
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if (sk->sk_family == AF_INET6 &&
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sk_is_tcp(sk) &&
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!ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))
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return;
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is_ipv6 = (sk->sk_family == AF_INET6 &&
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!ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr));
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#endif
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sk->sk_gso_max_size = GSO_LEGACY_MAX_SIZE;
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/* pairs with the WRITE_ONCE() in netif_set_gso(_ipv4)_max_size() */
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max_size = is_ipv6 ? READ_ONCE(dst->dev->gso_max_size) :
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READ_ONCE(dst->dev->gso_ipv4_max_size);
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if (max_size > GSO_LEGACY_MAX_SIZE && !sk_is_tcp(sk))
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max_size = GSO_LEGACY_MAX_SIZE;
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return max_size - (MAX_TCP_HEADER + 1);
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}
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void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
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@ -2403,10 +2408,7 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
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sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
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} else {
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sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
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/* pairs with the WRITE_ONCE() in netif_set_gso_max_size() */
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sk->sk_gso_max_size = READ_ONCE(dst->dev->gso_max_size);
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sk_trim_gso_size(sk);
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sk->sk_gso_max_size -= (MAX_TCP_HEADER + 1);
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sk->sk_gso_max_size = sk_dst_gso_max_size(sk, dst);
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/* pairs with the WRITE_ONCE() in netif_set_gso_max_segs() */
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max_segs = max_t(u32, READ_ONCE(dst->dev->gso_max_segs), 1);
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}
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@ -1485,6 +1485,7 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)
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if (unlikely(ip_fast_csum((u8 *)iph, 5)))
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goto out;
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NAPI_GRO_CB(skb)->proto = proto;
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id = ntohl(*(__be32 *)&iph->id);
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flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF));
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id >>= 16;
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@ -1618,9 +1619,9 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
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int inet_gro_complete(struct sk_buff *skb, int nhoff)
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{
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__be16 newlen = htons(skb->len - nhoff);
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struct iphdr *iph = (struct iphdr *)(skb->data + nhoff);
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const struct net_offload *ops;
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__be16 totlen = iph->tot_len;
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int proto = iph->protocol;
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int err = -ENOSYS;
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@ -1629,8 +1630,8 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff)
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skb_set_inner_network_header(skb, nhoff);
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}
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csum_replace2(&iph->check, iph->tot_len, newlen);
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iph->tot_len = newlen;
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iph_set_totlen(iph, skb->len - nhoff);
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csum_replace2(&iph->check, totlen, iph->tot_len);
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ops = rcu_dereference(inet_offloads[proto]);
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if (WARN_ON(!ops || !ops->callbacks.gro_complete))
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@ -511,7 +511,7 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net)
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if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
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goto csum_error;
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len = ntohs(iph->tot_len);
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len = iph_totlen(skb, iph);
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if (skb->len < len) {
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drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL;
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__IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS);
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@ -100,7 +100,7 @@ int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct iphdr *iph = ip_hdr(skb);
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iph->tot_len = htons(skb->len);
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iph_set_totlen(iph, skb->len);
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ip_send_check(iph);
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/* if egress device is enslaved to an L3 master device pass the
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