| Message ID | 637aa55b8dbf0c85c2ee8892df26a8bbbf9f2ef5.1674921359.git.lucien.xin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | b1a78b9b98862cda167b643690e43662ea060625 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: support ipv4 big tcp | expand |
On 1/28/23 8:58 AM, Xin Long wrote: > 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> > --- > net/core/gro.c | 12 +++++++----- > net/core/sock.c | 26 ++++++++++++++------------ > net/ipv4/af_inet.c | 7 ++++--- > net/ipv4/ip_input.c | 2 +- > net/ipv4/ip_output.c | 2 +- > 5 files changed, 27 insertions(+), 22 deletions(-) > Reviewed-by: David Ahern <dsahern@kernel.org>
Hello, (I reduced the Cc list to the maintainers of the files modified by this patch) On 28/01/2023 16:58, Xin Long wrote: > 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. (...) > diff --git a/net/core/gro.c b/net/core/gro.c > index 506f83d715f8..b15f85546bdd 100644 > --- a/net/core/gro.c > +++ b/net/core/gro.c > @@ -162,16 +162,18 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) > struct sk_buff *lp; > int segs; > > - /* pairs with WRITE_ONCE() in netif_set_gro_max_size() */ > - gro_max_size = READ_ONCE(p->dev->gro_max_size); > + /* pairs with WRITE_ONCE() in netif_set_gro(_ipv4)_max_size() */ > + gro_max_size = p->protocol == htons(ETH_P_IPV6) ? > + READ_ONCE(p->dev->gro_max_size) : > + READ_ONCE(p->dev->gro_ipv4_max_size); > FYI, we got a small conflict when merging -net in net-next in the MPTCP tree due to another patch from -net: 7d2c89b32587 ("skb: Do mix page pool and page referenced frags in GRO") and this one applied in net-next: b1a78b9b9886 ("net: add support for ipv4 big tcp") The conflict has been resolved on our side[1] by keeping the modifications from both sides and the resolution we suggest is attached to this email. Cheers, Matt [1] https://github.com/multipath-tcp/mptcp_net-next/commit/56e08652439a
diff --git a/net/core/gro.c b/net/core/gro.c index 506f83d715f8..b15f85546bdd 100644 --- a/net/core/gro.c +++ b/net/core/gro.c @@ -162,16 +162,18 @@ int skb_gro_receive(struct sk_buff *p, struct sk_buff *skb) struct sk_buff *lp; int segs; - /* pairs with WRITE_ONCE() in netif_set_gro_max_size() */ - gro_max_size = READ_ONCE(p->dev->gro_max_size); + /* pairs with WRITE_ONCE() in netif_set_gro(_ipv4)_max_size() */ + gro_max_size = p->protocol == htons(ETH_P_IPV6) ? + READ_ONCE(p->dev->gro_max_size) : + READ_ONCE(p->dev->gro_ipv4_max_size); if (unlikely(p->len + len >= gro_max_size || NAPI_GRO_CB(skb)->flush)) return -E2BIG; if (unlikely(p->len + len >= GRO_LEGACY_MAX_SIZE)) { - if (p->protocol != htons(ETH_P_IPV6) || - skb_headroom(p) < sizeof(struct hop_jumbo_hdr) || - ipv6_hdr(p)->nexthdr != IPPROTO_TCP || + if (NAPI_GRO_CB(skb)->proto != IPPROTO_TCP || + (p->protocol == htons(ETH_P_IPV6) && + skb_headroom(p) < sizeof(struct hop_jumbo_hdr)) || p->encapsulation) return -E2BIG; } diff --git a/net/core/sock.c b/net/core/sock.c index 7ba4891460ad..f08b76acde9b 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2373,17 +2373,22 @@ void sk_free_unlock_clone(struct sock *sk) } EXPORT_SYMBOL_GPL(sk_free_unlock_clone); -static void sk_trim_gso_size(struct sock *sk) +static u32 sk_dst_gso_max_size(struct sock *sk, struct dst_entry *dst) { - if (sk->sk_gso_max_size <= GSO_LEGACY_MAX_SIZE) - return; + bool is_ipv6 = false; + u32 max_size; + #if IS_ENABLED(CONFIG_IPV6) - if (sk->sk_family == AF_INET6 && - sk_is_tcp(sk) && - !ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)) - return; + is_ipv6 = (sk->sk_family == AF_INET6 && + !ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr)); #endif - sk->sk_gso_max_size = GSO_LEGACY_MAX_SIZE; + /* pairs with the WRITE_ONCE() in netif_set_gso(_ipv4)_max_size() */ + max_size = is_ipv6 ? READ_ONCE(dst->dev->gso_max_size) : + READ_ONCE(dst->dev->gso_ipv4_max_size); + if (max_size > GSO_LEGACY_MAX_SIZE && !sk_is_tcp(sk)) + max_size = GSO_LEGACY_MAX_SIZE; + + return max_size - (MAX_TCP_HEADER + 1); } void sk_setup_caps(struct sock *sk, struct dst_entry *dst) @@ -2403,10 +2408,7 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst) sk->sk_route_caps &= ~NETIF_F_GSO_MASK; } else { sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM; - /* pairs with the WRITE_ONCE() in netif_set_gso_max_size() */ - sk->sk_gso_max_size = READ_ONCE(dst->dev->gso_max_size); - sk_trim_gso_size(sk); - sk->sk_gso_max_size -= (MAX_TCP_HEADER + 1); + sk->sk_gso_max_size = sk_dst_gso_max_size(sk, dst); /* pairs with the WRITE_ONCE() in netif_set_gso_max_segs() */ max_segs = max_t(u32, READ_ONCE(dst->dev->gso_max_segs), 1); } diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 6c0ec2789943..2f992a323b95 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1485,6 +1485,7 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) if (unlikely(ip_fast_csum((u8 *)iph, 5))) goto out; + NAPI_GRO_CB(skb)->proto = proto; id = ntohl(*(__be32 *)&iph->id); flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF)); id >>= 16; @@ -1618,9 +1619,9 @@ int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len) int inet_gro_complete(struct sk_buff *skb, int nhoff) { - __be16 newlen = htons(skb->len - nhoff); struct iphdr *iph = (struct iphdr *)(skb->data + nhoff); const struct net_offload *ops; + __be16 totlen = iph->tot_len; int proto = iph->protocol; int err = -ENOSYS; @@ -1629,8 +1630,8 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff) skb_set_inner_network_header(skb, nhoff); } - csum_replace2(&iph->check, iph->tot_len, newlen); - iph->tot_len = newlen; + iph_set_totlen(iph, skb->len - nhoff); + csum_replace2(&iph->check, totlen, iph->tot_len); ops = rcu_dereference(inet_offloads[proto]); if (WARN_ON(!ops || !ops->callbacks.gro_complete)) diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index e880ce77322a..fe9ead9ee863 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -511,7 +511,7 @@ static struct sk_buff *ip_rcv_core(struct sk_buff *skb, struct net *net) if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl))) goto csum_error; - len = ntohs(iph->tot_len); + len = iph_totlen(skb, iph); if (skb->len < len) { drop_reason = SKB_DROP_REASON_PKT_TOO_SMALL; __IP_INC_STATS(net, IPSTATS_MIB_INTRUNCATEDPKTS); diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 922c87ef1ab5..4e4e308c3230 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -100,7 +100,7 @@ int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb) { struct iphdr *iph = ip_hdr(skb); - iph->tot_len = htons(skb->len); + iph_set_totlen(iph, skb->len); ip_send_check(iph); /* if egress device is enslaved to an L3 master device pass the
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> --- net/core/gro.c | 12 +++++++----- net/core/sock.c | 26 ++++++++++++++------------ net/ipv4/af_inet.c | 7 ++++--- net/ipv4/ip_input.c | 2 +- net/ipv4/ip_output.c | 2 +- 5 files changed, 27 insertions(+), 22 deletions(-)