Re: [PATCH v5] ipvs: allow tunneling with gue encapsulation

Julian Anastasov
2019-03-21T20:29:57Z

Hello,

On Tue, 19 Mar 2019, Jacky Hu wrote:

> ipip packets are blocked in some public cloud environments, this patch
> allows gue encapsulation with the tunneling method, which would make
> tunneling working in those environments.
>
> Signed-off-by: Jacky Hu <hengqing.hu@gmail.com>

The patch looks good to me, thanks!

Acked-by: Julian Anastasov <ja@ssi.bg>

I plan to add the needed ICMP-error support for the new tunnel
type in the following days, as a followup patch.

> ---
> include/net/ip_vs.h | 5 ++
> include/uapi/linux/ip_vs.h | 11 +++
> net/netfilter/ipvs/ip_vs_ctl.c | 43 ++++++++++-
> net/netfilter/ipvs/ip_vs_xmit.c | 124 ++++++++++++++++++++++++++++++--
> 4 files changed, 178 insertions(+), 5 deletions(-)
>
> diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
> index a0d2e0bb9a94..cdc7b621930d 100644
> --- a/include/net/ip_vs.h
> +++ b/include/net/ip_vs.h
> @@ -603,6 +603,9 @@ struct ip_vs_dest_user_kern {
>
> /* Address family of addr */
> u16 af;
> +
> + u16 tun_type; /* tunnel type */
> + __be16 tun_port; /* tunnel port */
> };
>
>
> @@ -663,6 +666,8 @@ struct ip_vs_dest {
> atomic_t conn_flags; /* flags to copy to conn */
> atomic_t weight; /* server weight */
> atomic_t last_weight; /* server latest weight */
> + __u16 tun_type; /* tunnel type */
> + __be16 tun_port; /* tunnel port */
>
> 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 1c916b2f89dc..e34f436fc79d 100644
> --- a/include/uapi/linux/ip_vs.h
> +++ b/include/uapi/linux/ip_vs.h
> @@ -124,6 +124,13 @@
>
> #define IP_VS_PEDATA_MAXLEN 255
>
> +/* Tunnel types */
> +enum {
> + IP_VS_CONN_F_TUNNEL_TYPE_IPIP = 0, /* IPIP */
> + IP_VS_CONN_F_TUNNEL_TYPE_GUE, /* GUE */
> + IP_VS_CONN_F_TUNNEL_TYPE_MAX,
> +};
> +
> /*
> * The struct ip_vs_service_user and struct ip_vs_dest_user are
> * used to set IPVS rules through setsockopt.
> @@ -392,6 +399,10 @@ enum {
>
> IPVS_DEST_ATTR_STATS64, /* nested attribute for dest stats */
>
> + IPVS_DEST_ATTR_TUN_TYPE, /* tunnel type */
> +
> + IPVS_DEST_ATTR_TUN_PORT, /* tunnel port */
> +
> __IPVS_DEST_ATTR_MAX,
> };
>
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 432141f04af3..ddee6266b78b 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -830,6 +830,10 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
> conn_flags = udest->conn_flags & IP_VS_CONN_F_DEST_MASK;
> conn_flags |= IP_VS_CONN_F_INACTIVE;
>
> + /* set the tunnel info */
> + dest->tun_type = udest->tun_type;
> + dest->tun_port = udest->tun_port;
> +
> /* 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) {
> conn_flags |= IP_VS_CONN_F_NOOUTPUT;
> @@ -980,6 +984,17 @@ ip_vs_add_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
> return -ERANGE;
> }
>
> + switch (udest->tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + if (udest->tun_port == 0) {
> + pr_err("%s(): tunnel port is zero\n", __func__);
> + return -EINVAL;
> + }
> + break;
> + default:
> + break;
> + }
> +
> ip_vs_addr_copy(udest->af, &daddr, &udest->addr);
>
> /* We use function that requires RCU lock */
> @@ -1044,6 +1059,17 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest)
> return -ERANGE;
> }
>
> + switch (udest->tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + if (udest->tun_port == 0) {
> + pr_err("%s(): tunnel port is zero\n", __func__);
> + return -EINVAL;
> + }
> + break;
> + default:
> + break;
> + }
> +
> ip_vs_addr_copy(udest->af, &daddr, &udest->addr);
>
> /* We use function that requires RCU lock */
> @@ -2310,6 +2336,7 @@ static void ip_vs_copy_udest_compat(struct ip_vs_dest_user_kern *udest,
> udest->u_threshold = udest_compat->u_threshold;
> udest->l_threshold = udest_compat->l_threshold;
> udest->af = AF_INET;
> + udest->tun_type = IP_VS_CONN_F_TUNNEL_TYPE_IPIP;
> }
>
> static int
> @@ -2869,6 +2896,8 @@ static const struct nla_policy ip_vs_dest_policy[IPVS_DEST_ATTR_MAX + 1] = {
> [IPVS_DEST_ATTR_PERSIST_CONNS] = { .type = NLA_U32 },
> [IPVS_DEST_ATTR_STATS] = { .type = NLA_NESTED },
> [IPVS_DEST_ATTR_ADDR_FAMILY] = { .type = NLA_U16 },
> + [IPVS_DEST_ATTR_TUN_TYPE] = { .type = NLA_U8 },
> + [IPVS_DEST_ATTR_TUN_PORT] = { .type = NLA_U16 },
> };
>
> static int ip_vs_genl_fill_stats(struct sk_buff *skb, int container_type,
> @@ -3172,6 +3201,10 @@ static int ip_vs_genl_fill_dest(struct sk_buff *skb, struct ip_vs_dest *dest)
> IP_VS_CONN_F_FWD_MASK)) ||
> nla_put_u32(skb, IPVS_DEST_ATTR_WEIGHT,
> atomic_read(&dest->weight)) ||
> + nla_put_u8(skb, IPVS_DEST_ATTR_TUN_TYPE,
> + dest->tun_type) ||
> + nla_put_be16(skb, IPVS_DEST_ATTR_TUN_PORT,
> + dest->tun_port) ||
> 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,
> @@ -3294,12 +3327,14 @@ 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_l_thresh, *nla_tun_type, *nla_tun_port;
>
> nla_fwd = attrs[IPVS_DEST_ATTR_FWD_METHOD];
> nla_weight = attrs[IPVS_DEST_ATTR_WEIGHT];
> nla_u_thresh = attrs[IPVS_DEST_ATTR_U_THRESH];
> 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];
>
> if (!(nla_fwd && nla_weight && nla_u_thresh && nla_l_thresh))
> return -EINVAL;
> @@ -3309,6 +3344,12 @@ static int ip_vs_genl_parse_dest(struct ip_vs_dest_user_kern *udest,
> udest->weight = nla_get_u32(nla_weight);
> udest->u_threshold = nla_get_u32(nla_u_thresh);
> udest->l_threshold = nla_get_u32(nla_l_thresh);
> +
> + if (nla_tun_type)
> + udest->tun_type = nla_get_u8(nla_tun_type);
> +
> + if (nla_tun_port)
> + udest->tun_port = nla_get_be16(nla_tun_port);
> }
>
> return 0;
> diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
> index 473cce2a5231..730e108b9f36 100644
> --- a/net/netfilter/ipvs/ip_vs_xmit.c
> +++ b/net/netfilter/ipvs/ip_vs_xmit.c
> @@ -32,6 +32,7 @@
> #include <linux/slab.h>
> #include <linux/tcp.h> /* for tcphdr */
> #include <net/ip.h>
> +#include <net/gue.h>
> #include <net/tcp.h> /* for csum_tcpudp_magic */
> #include <net/udp.h>
> #include <net/icmp.h> /* for icmp_send */
> @@ -382,6 +383,15 @@ __ip_vs_get_out_rt(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
> mtu = dst_mtu(&rt->dst);
> } else {
> mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
> + if (!dest)
> + goto err_put;
> + switch (dest->tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
> + break;
> + default:
> + break;
> + }
> if (mtu < 68) {
> IP_VS_DBG_RL("%s(): mtu less than 68\n", __func__);
> goto err_put;
> @@ -533,6 +543,15 @@ __ip_vs_get_out_rt_v6(struct netns_ipvs *ipvs, int skb_af, struct sk_buff *skb,
> mtu = dst_mtu(&rt->dst);
> else {
> mtu = dst_mtu(&rt->dst) - sizeof(struct ipv6hdr);
> + if (!dest)
> + goto err_put;
> + switch (dest->tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + mtu -= sizeof(struct udphdr) + sizeof(struct guehdr);
> + break;
> + default:
> + break;
> + }
> if (mtu < IPV6_MIN_MTU) {
> IP_VS_DBG_RL("%s(): mtu less than %d\n", __func__,
> IPV6_MIN_MTU);
> @@ -989,6 +1008,41 @@ static inline int __tun_gso_type_mask(int encaps_af, int orig_af)
> }
> }
>
> +static int
> +ipvs_gue_encap(struct net *net, struct sk_buff *skb,
> + struct ip_vs_conn *cp, __u8 *next_protocol)
> +{
> + __be16 dport;
> + __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 */
> +
> + skb_push(skb, sizeof(struct guehdr));
> +
> + gueh = (struct guehdr *)skb->data;
> +
> + gueh->control = 0;
> + gueh->version = 0;
> + gueh->hlen = 0;
> + gueh->flags = 0;
> + gueh->proto_ctype = *next_protocol;
> +
> + skb_push(skb, sizeof(struct udphdr));
> + skb_reset_transport_header(skb);
> +
> + udph = udp_hdr(skb);
> +
> + dport = cp->dest->tun_port;
> + udph->dest = dport;
> + udph->source = sport;
> + udph->len = htons(skb->len);
> + udph->check = 0;
> +
> + *next_protocol = IPPROTO_UDP;
> +
> + return 0;
> +}
> +
> /*
> * IP Tunneling transmitter
> *
> @@ -1025,6 +1079,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
> struct iphdr *iph; /* Our new IP header */
> unsigned int max_headroom; /* The extra header space needed */
> int ret, local;
> + int tun_type, gso_type;
>
> EnterFunction(10);
>
> @@ -1046,6 +1101,16 @@ 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;
> +
> + switch (tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
> + break;
> + default:
> + break;
> + }
> +
> /* We only care about the df field if sysctl_pmtu_disc(ipvs) is set */
> dfp = sysctl_pmtu_disc(ipvs) ? &df : NULL;
> skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
> @@ -1054,11 +1119,30 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
> if (IS_ERR(skb))
> goto tx_error;
>
> - if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET, cp->af)))
> + switch (tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + gso_type = SKB_GSO_UDP_TUNNEL;
> + break;
> + default:
> + gso_type = __tun_gso_type_mask(AF_INET, cp->af);
> + break;
> + }
> +
> + if (iptunnel_handle_offloads(skb, gso_type))
> goto tx_error;
>
> skb->transport_header = skb->network_header;
>
> + skb_set_inner_ipproto(skb, next_protocol);
> +
> + switch (tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + ipvs_gue_encap(net, skb, cp, &next_protocol);
> + break;
> + default:
> + break;
> + }
> +
> skb_push(skb, sizeof(struct iphdr));
> skb_reset_network_header(skb);
> memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
> @@ -1102,6 +1186,8 @@ int
> ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
> struct ip_vs_protocol *pp, struct ip_vs_iphdr *ipvsh)
> {
> + struct netns_ipvs *ipvs = cp->ipvs;
> + struct net *net = ipvs->net;
> struct rt6_info *rt; /* Route to the other host */
> struct in6_addr saddr; /* Source for tunnel */
> struct net_device *tdev; /* Device to other host */
> @@ -1112,10 +1198,11 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
> struct ipv6hdr *iph; /* Our new IP header */
> unsigned int max_headroom; /* The extra header space needed */
> int ret, local;
> + int tun_type, gso_type;
>
> EnterFunction(10);
>
> - local = __ip_vs_get_out_rt_v6(cp->ipvs, cp->af, skb, cp->dest,
> + local = __ip_vs_get_out_rt_v6(ipvs, cp->af, skb, cp->dest,
> &cp->daddr.in6,
> &saddr, ipvsh, 1,
> IP_VS_RT_MODE_LOCAL |
> @@ -1134,17 +1221,46 @@ 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;
> +
> + switch (tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + max_headroom += sizeof(struct udphdr) + sizeof(struct guehdr);
> + break;
> + default:
> + break;
> + }
> +
> skb = ip_vs_prepare_tunneled_skb(skb, cp->af, max_headroom,
> &next_protocol, &payload_len,
> &dsfield, &ttl, NULL);
> if (IS_ERR(skb))
> goto tx_error;
>
> - if (iptunnel_handle_offloads(skb, __tun_gso_type_mask(AF_INET6, cp->af)))
> + switch (tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + gso_type = SKB_GSO_UDP_TUNNEL;
> + break;
> + default:
> + gso_type = __tun_gso_type_mask(AF_INET6, cp->af);
> + break;
> + }
> +
> + if (iptunnel_handle_offloads(skb, gso_type))
> goto tx_error;
>
> skb->transport_header = skb->network_header;
>
> + skb_set_inner_ipproto(skb, next_protocol);
> +
> + switch (tun_type) {
> + case IP_VS_CONN_F_TUNNEL_TYPE_GUE:
> + ipvs_gue_encap(net, skb, cp, &next_protocol);
> + break;
> + default:
> + break;
> + }
> +
> skb_push(skb, sizeof(struct ipv6hdr));
> skb_reset_network_header(skb);
> memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
> @@ -1167,7 +1283,7 @@ ip_vs_tunnel_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
>
> ret = ip_vs_tunnel_xmit_prepare(skb, cp);
> if (ret == NF_ACCEPT)
> - ip6_local_out(cp->ipvs->net, skb->sk, skb);
> + ip6_local_out(net, skb->sk, skb);
> else if (ret == NF_DROP)
> kfree_skb(skb);
>
> --
> 2.21.0

Regards

--
Julian Anastasov <ja@ssi.bg>