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Re: [PATCH v4] ipvs: add checksum support for gue encapsulation

To: Jacky Hu <hengqing.hu@xxxxxxxxx>
Subject: Re: [PATCH v4] ipvs: add checksum support for gue encapsulation
Cc: jacky.hu@xxxxxxxxxxx, jason.niesz@xxxxxxxxxxx, Wensong Zhang <wensong@xxxxxxxxxxxx>, Simon Horman <horms@xxxxxxxxxxxx>, "David S. Miller" <davem@xxxxxxxxxxxxx>, Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>, Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>, Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxxxxxx>, Florian Westphal <fw@xxxxxxxxx>, netdev@xxxxxxxxxxxxxxx, lvs-devel@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, netfilter-devel@xxxxxxxxxxxxxxx, coreteam@xxxxxxxxxxxxx
From: Julian Anastasov <ja@xxxxxx>
Date: Thu, 30 May 2019 10:10:15 +0300 (EEST)
        Hello,

On Thu, 30 May 2019, Jacky Hu wrote:

> Add checksum support for gue encapsulation with the tun_flags parameter,
> which could be one of the values below:
> IP_VS_TUNNEL_ENCAP_FLAG_NOCSUM
> IP_VS_TUNNEL_ENCAP_FLAG_CSUM
> IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM
> 
> Signed-off-by: Jacky Hu <hengqing.hu@xxxxxxxxx>

        Looks good to me, thanks!

Signed-off-by: Julian Anastasov <ja@xxxxxx>

> ---
> v4->v3:
>   1) defer pd assignment after data += GUE_LEN_PRIV
> 
> v3->v2:
>   1) fixed CHECK: spaces preferred around that '<<' (ctx:VxV)
> 
> v2->v1:
>   1) removed unnecessary changes to ip_vs_core.c
>   2) use correct nla_get/put function for tun_flags
>   3) use correct gue hdrlen for skb_push in ipvs_gue_encap
>   4) moved declaration of gue_hdrlen and gue_optlen
> 
>  include/net/ip_vs.h             |   2 +
>  include/uapi/linux/ip_vs.h      |   7 ++
>  net/netfilter/ipvs/ip_vs_ctl.c  |  11 ++-
>  net/netfilter/ipvs/ip_vs_xmit.c | 143 ++++++++++++++++++++++++++++----
>  4 files changed, 146 insertions(+), 17 deletions(-)
> 
> diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
> index b01a94ebfc0e..cb1ad0cc5c7b 100644
> --- a/include/net/ip_vs.h
> +++ b/include/net/ip_vs.h
> @@ -603,6 +603,7 @@ struct ip_vs_dest_user_kern {
>  
>       u16                     tun_type;       /* tunnel type */
>       __be16                  tun_port;       /* tunnel port */
> +     u16                     tun_flags;      /* tunnel flags */
>  };
>  
>  
> @@ -665,6 +666,7 @@ struct ip_vs_dest {
>       atomic_t                last_weight;    /* server latest weight */
>       __u16                   tun_type;       /* tunnel type */
>       __be16                  tun_port;       /* tunnel port */
> +     __u16                   tun_flags;      /* tunnel flags */
>  
>       refcount_t              refcnt;         /* reference counter */
>       struct ip_vs_stats      stats;          /* statistics */
> diff --git a/include/uapi/linux/ip_vs.h b/include/uapi/linux/ip_vs.h
> index e34f436fc79d..e4f18061a4fd 100644
> --- a/include/uapi/linux/ip_vs.h
> +++ b/include/uapi/linux/ip_vs.h
> @@ -131,6 +131,11 @@ enum {
>       IP_VS_CONN_F_TUNNEL_TYPE_MAX,
>  };
>  
> +/* Tunnel encapsulation flags */
> +#define IP_VS_TUNNEL_ENCAP_FLAG_NOCSUM               (0)
> +#define IP_VS_TUNNEL_ENCAP_FLAG_CSUM         (1 << 0)
> +#define IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM              (1 << 1)
> +
>  /*
>   *   The struct ip_vs_service_user and struct ip_vs_dest_user are
>   *   used to set IPVS rules through setsockopt.
> @@ -403,6 +408,8 @@ enum {
>  
>       IPVS_DEST_ATTR_TUN_PORT,        /* tunnel port */
>  
> +     IPVS_DEST_ATTR_TUN_FLAGS,       /* tunnel flags */
> +
>       __IPVS_DEST_ATTR_MAX,
>  };
>  
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index d5847e06350f..ad19ac08622f 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -893,6 +893,7 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct 
> ip_vs_dest *dest,
>       /* set the tunnel info */
>       dest->tun_type = udest->tun_type;
>       dest->tun_port = udest->tun_port;
> +     dest->tun_flags = udest->tun_flags;
>  
>       /* set the IP_VS_CONN_F_NOOUTPUT flag if not masquerading/NAT */
>       if ((conn_flags & IP_VS_CONN_F_FWD_MASK) != IP_VS_CONN_F_MASQ) {
> @@ -2967,6 +2968,7 @@ static const struct nla_policy 
> ip_vs_dest_policy[IPVS_DEST_ATTR_MAX + 1] = {
>       [IPVS_DEST_ATTR_ADDR_FAMILY]    = { .type = NLA_U16 },
>       [IPVS_DEST_ATTR_TUN_TYPE]       = { .type = NLA_U8 },
>       [IPVS_DEST_ATTR_TUN_PORT]       = { .type = NLA_U16 },
> +     [IPVS_DEST_ATTR_TUN_FLAGS]      = { .type = NLA_U16 },
>  };
>  
>  static int ip_vs_genl_fill_stats(struct sk_buff *skb, int container_type,
> @@ -3273,6 +3275,8 @@ static int ip_vs_genl_fill_dest(struct sk_buff *skb, 
> struct ip_vs_dest *dest)
>                      dest->tun_type) ||
>           nla_put_be16(skb, IPVS_DEST_ATTR_TUN_PORT,
>                        dest->tun_port) ||
> +         nla_put_u16(skb, IPVS_DEST_ATTR_TUN_FLAGS,
> +                     dest->tun_flags) ||
>           nla_put_u32(skb, IPVS_DEST_ATTR_U_THRESH, dest->u_threshold) ||
>           nla_put_u32(skb, IPVS_DEST_ATTR_L_THRESH, dest->l_threshold) ||
>           nla_put_u32(skb, IPVS_DEST_ATTR_ACTIVE_CONNS,
> @@ -3393,7 +3397,8 @@ static int ip_vs_genl_parse_dest(struct 
> ip_vs_dest_user_kern *udest,
>       /* If a full entry was requested, check for the additional fields */
>       if (full_entry) {
>               struct nlattr *nla_fwd, *nla_weight, *nla_u_thresh,
> -                           *nla_l_thresh, *nla_tun_type, *nla_tun_port;
> +                           *nla_l_thresh, *nla_tun_type, *nla_tun_port,
> +                           *nla_tun_flags;
>  
>               nla_fwd         = attrs[IPVS_DEST_ATTR_FWD_METHOD];
>               nla_weight      = attrs[IPVS_DEST_ATTR_WEIGHT];
> @@ -3401,6 +3406,7 @@ static int ip_vs_genl_parse_dest(struct 
> ip_vs_dest_user_kern *udest,
>               nla_l_thresh    = attrs[IPVS_DEST_ATTR_L_THRESH];
>               nla_tun_type    = attrs[IPVS_DEST_ATTR_TUN_TYPE];
>               nla_tun_port    = attrs[IPVS_DEST_ATTR_TUN_PORT];
> +             nla_tun_flags   = attrs[IPVS_DEST_ATTR_TUN_FLAGS];
>  
>               if (!(nla_fwd && nla_weight && nla_u_thresh && nla_l_thresh))
>                       return -EINVAL;
> @@ -3416,6 +3422,9 @@ static int ip_vs_genl_parse_dest(struct 
> ip_vs_dest_user_kern *udest,
>  
>               if (nla_tun_port)
>                       udest->tun_port = nla_get_be16(nla_tun_port);
> +
> +             if (nla_tun_flags)
> +                     udest->tun_flags = nla_get_u16(nla_tun_flags);
>       }
>  
>       return 0;
> diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
> index 8d6f94b67772..4b76557ab4ad 100644
> --- a/net/netfilter/ipvs/ip_vs_xmit.c
> +++ b/net/netfilter/ipvs/ip_vs_xmit.c
> @@ -40,6 +40,7 @@
>  #include <net/ipv6.h>
>  #include <net/ip6_route.h>
>  #include <net/ip_tunnels.h>
> +#include <net/ip6_checksum.h>
>  #include <net/addrconf.h>
>  #include <linux/icmpv6.h>
>  #include <linux/netfilter.h>
> @@ -385,8 +386,13 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, 
> struct sk_buff *skb,
>               mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
>               if (!dest)
>                       goto err_put;
> -             if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> +             if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
>                       mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
> +                     if ((dest->tun_flags &
> +                          IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +                         skb->ip_summed == CHECKSUM_PARTIAL)
> +                             mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
> +             }
>               if (mtu < 68) {
>                       IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
>                       goto err_put;
> @@ -540,8 +546,13 @@ __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int 
> skb_af, struct sk_buff *skb,
>               mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
>               if (!dest)
>                       goto err_put;
> -             if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> +             if (dest->tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
>                       mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
> +                     if ((dest->tun_flags &
> +                          IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +                         skb->ip_summed == CHECKSUM_PARTIAL)
> +                             mtu -= GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
> +             }
>               if (mtu < IPV6_MIN_MTU) {
>                       IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
>                                    IPV6_MIN_MTU);
> @@ -1006,17 +1017,56 @@ ipvs_gue_encap(struct net *net, struct sk_buff *skb,
>       __be16 sport = udp_flow_src_port(net, skb, 0, 0, false);
>       struct udphdr  *udph;   /* Our new UDP header */
>       struct guehdr  *gueh;   /* Our new GUE header */
> +     size_t hdrlen, optlen = 0;
> +     void *data;
> +     bool need_priv = false;
> +
> +     if ((cp->dest->tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +         skb->ip_summed == CHECKSUM_PARTIAL) {
> +             optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
> +             need_priv = true;
> +     }
>  
> -     skb_push(skb, sizeof(struct guehdr));
> +     hdrlen = sizeof(struct guehdr) + optlen;
> +
> +     skb_push(skb, hdrlen);
>  
>       gueh = (struct guehdr *)skb->data;
>  
>       gueh->control = 0;
>       gueh->version = 0;
> -     gueh->hlen = 0;
> +     gueh->hlen = optlen >> 2;
>       gueh->flags = 0;
>       gueh->proto_ctype = *next_protocol;
>  
> +     data = &gueh[1];
> +
> +     if (need_priv) {
> +             __be32 *flags = data;
> +             u16 csum_start = skb_checksum_start_offset(skb);
> +             __be16 *pd;
> +
> +             gueh->flags |= GUE_FLAG_PRIV;
> +             *flags = 0;
> +             data += GUE_LEN_PRIV;
> +
> +             if (csum_start < hdrlen)
> +                     return -EINVAL;
> +
> +             csum_start -= hdrlen;
> +             pd = data;
> +             pd[0] = htons(csum_start);
> +             pd[1] = htons(csum_start + skb->csum_offset);
> +
> +             if (!skb_is_gso(skb)) {
> +                     skb->ip_summed = CHECKSUM_NONE;
> +                     skb->encapsulation = 0;
> +             }
> +
> +             *flags |= GUE_PFLAG_REMCSUM;
> +             data += GUE_PLEN_REMCSUM;
> +     }
> +
>       skb_push(skb, sizeof(struct udphdr));
>       skb_reset_transport_header(skb);
>  
> @@ -1070,6 +1120,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>       unsigned int max_headroom;              /* The extra header space 
> needed */
>       int ret, local;
>       int tun_type, gso_type;
> +     int tun_flags;
>  
>       EnterFunction(10);
>  
> @@ -1092,9 +1143,19 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>       max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr);
>  
>       tun_type = cp->dest->tun_type;
> +     tun_flags = cp->dest->tun_flags;
>  
> -     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> -             max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
> +     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
> +             size_t gue_hdrlen, gue_optlen = 0;
> +
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +                 skb->ip_summed == CHECKSUM_PARTIAL) {
> +                     gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
> +             }
> +             gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
> +
> +             max_headroom += sizeof(struct udphdr) + gue_hdrlen;
> +     }
>  
>       /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
>       dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
> @@ -1105,8 +1166,17 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>               goto tx_error;
>  
>       gso_type = __tun_gso_type_mask(AF_INET, cp->af);
> -     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> -             gso_type |= SKB_GSO_UDP_TUNNEL;
> +     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
> +                 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
> +                     gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
> +             else
> +                     gso_type |= SKB_GSO_UDP_TUNNEL;
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +                 skb->ip_summed == CHECKSUM_PARTIAL) {
> +                     gso_type |= SKB_GSO_TUNNEL_REMCSUM;
> +             }
> +     }
>  
>       if (iptunnel_handle_offloads(skb, gso_type))
>               goto tx_error;
> @@ -1115,8 +1185,19 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>  
>       skb_set_inner_ipproto(skb, next_protocol);
>  
> -     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> -             ipvs_gue_encap(net, skb, cp, &next_protocol);
> +     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
> +             bool check = false;
> +
> +             if (ipvs_gue_encap(net, skb, cp, &next_protocol))
> +                     goto tx_error;
> +
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
> +                 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
> +                     check = true;
> +
> +             udp_set_csum(!check, skb, saddr, cp->daddr.ip, skb->len);
> +     }
> +
>  
>       skb_push(skb, sizeof(struct iphdr));
>       skb_reset_network_header(skb);
> @@ -1174,6 +1255,7 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>       unsigned int max_headroom;      /* The extra header space needed */
>       int ret, local;
>       int tun_type, gso_type;
> +     int tun_flags;
>  
>       EnterFunction(10);
>  
> @@ -1197,9 +1279,19 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>       max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr);
>  
>       tun_type = cp->dest->tun_type;
> +     tun_flags = cp->dest->tun_flags;
>  
> -     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> -             max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
> +     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
> +             size_t gue_hdrlen, gue_optlen = 0;
> +
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +                 skb->ip_summed == CHECKSUM_PARTIAL) {
> +                     gue_optlen += GUE_PLEN_REMCSUM + GUE_LEN_PRIV;
> +             }
> +             gue_hdrlen = sizeof(struct guehdr) + gue_optlen;
> +
> +             max_headroom += sizeof(struct udphdr) + gue_hdrlen;
> +     }
>  
>       skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
>                                        &next_protocol, &payload_len,
> @@ -1208,8 +1300,17 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>               goto tx_error;
>  
>       gso_type = __tun_gso_type_mask(AF_INET6, cp->af);
> -     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> -             gso_type |= SKB_GSO_UDP_TUNNEL;
> +     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
> +                 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
> +                     gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
> +             else
> +                     gso_type |= SKB_GSO_UDP_TUNNEL;
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM) &&
> +                 skb->ip_summed == CHECKSUM_PARTIAL) {
> +                     gso_type |= SKB_GSO_TUNNEL_REMCSUM;
> +             }
> +     }
>  
>       if (iptunnel_handle_offloads(skb, gso_type))
>               goto tx_error;
> @@ -1218,8 +1319,18 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct 
> ip_vs_conn *cp,
>  
>       skb_set_inner_ipproto(skb, next_protocol);
>  
> -     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE)
> -             ipvs_gue_encap(net, skb, cp, &next_protocol);
> +     if (tun_type == IP_VS_CONN_F_TUNNEL_TYPE_GUE) {
> +             bool check = false;
> +
> +             if (ipvs_gue_encap(net, skb, cp, &next_protocol))
> +                     goto tx_error;
> +
> +             if ((tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_CSUM) ||
> +                 (tun_flags & IP_VS_TUNNEL_ENCAP_FLAG_REMCSUM))
> +                     check = true;
> +
> +             udp6_set_csum(!check, skb, &saddr, &cp->daddr.in6, skb->len);
> +     }
>  
>       skb_push(skb, sizeof(struct ipv6hdr));
>       skb_reset_network_header(skb);
> -- 
> 2.21.0

Regards

--
Julian Anastasov <ja@xxxxxx>

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